| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Peter Zijlstra | 20656 | 39.27% | 411 | 37.78% |
| Alexander Shishkin | 4530 | 8.61% | 36 | 3.31% |
| Stéphane Eranian | 2832 | 5.38% | 40 | 3.68% |
| Frédéric Weisbecker | 2528 | 4.81% | 42 | 3.86% |
| Kyle Huey | 2487 | 4.73% | 5 | 0.46% |
| Jiri Olsa | 1730 | 3.29% | 36 | 3.31% |
| Paul Mackerras | 1646 | 3.13% | 25 | 2.30% |
| Ingo Molnar | 1435 | 2.73% | 37 | 3.40% |
| Kan Liang | 1383 | 2.63% | 25 | 2.30% |
| Song Liu | 1353 | 2.57% | 19 | 1.75% |
| Namhyung Kim | 1223 | 2.33% | 21 | 1.93% |
| Adrian Hunter | 1046 | 1.99% | 7 | 0.64% |
| Thomas Gleixner | 827 | 1.57% | 13 | 1.19% |
| Arnaldo Carvalho de Melo | 667 | 1.27% | 7 | 0.64% |
| Ian Rogers | 650 | 1.24% | 7 | 0.64% |
| Marco Elver | 562 | 1.07% | 10 | 0.92% |
| Hari Bathini | 531 | 1.01% | 1 | 0.09% |
| Alexei Starovoitov | 414 | 0.79% | 12 | 1.10% |
| Alexey Budankov | 376 | 0.71% | 5 | 0.46% |
| Yan Zheng | 288 | 0.55% | 9 | 0.83% |
| Markus Metzger | 227 | 0.43% | 1 | 0.09% |
| Ravi Bangoria | 216 | 0.41% | 6 | 0.55% |
| Sukadev Bhattiprolu | 212 | 0.40% | 4 | 0.37% |
| David Carrillo-Cisneros | 211 | 0.40% | 8 | 0.74% |
| Al Viro | 205 | 0.39% | 9 | 0.83% |
| Oleg Nesterov | 192 | 0.37% | 6 | 0.55% |
| Wang Nan | 186 | 0.35% | 3 | 0.28% |
| Li Zefan | 171 | 0.33% | 5 | 0.46% |
| Arjan van de Ven | 161 | 0.31% | 2 | 0.18% |
| Dave Hansen | 153 | 0.29% | 1 | 0.09% |
| Like Xu | 152 | 0.29% | 2 | 0.18% |
| Sebastian Andrzej Siewior | 149 | 0.28% | 8 | 0.74% |
| Sean Christopherson | 142 | 0.27% | 4 | 0.37% |
| Joel A Fernandes | 132 | 0.25% | 1 | 0.09% |
| Mark Rutland | 130 | 0.25% | 10 | 0.92% |
| Xia Kaixu | 130 | 0.25% | 1 | 0.09% |
| Milind Chabbi | 124 | 0.24% | 1 | 0.09% |
| Greg Kroah-Hartman | 118 | 0.22% | 2 | 0.18% |
| Yonghong Song | 105 | 0.20% | 9 | 0.83% |
| Daniel Borkmann | 99 | 0.19% | 6 | 0.55% |
| Pawel Moll | 96 | 0.18% | 1 | 0.09% |
| Tejun Heo | 94 | 0.18% | 13 | 1.19% |
| Chengming Zhou | 78 | 0.15% | 5 | 0.46% |
| Andrii Nakryiko | 76 | 0.14% | 3 | 0.28% |
| Andrew Lutomirski | 75 | 0.14% | 4 | 0.37% |
| Cody P Schafer | 72 | 0.14% | 1 | 0.09% |
| Andi Kleen | 66 | 0.13% | 3 | 0.28% |
| leilei.lin | 64 | 0.12% | 2 | 0.18% |
| James Clark | 59 | 0.11% | 2 | 0.18% |
| Matt Helsley | 55 | 0.10% | 2 | 0.18% |
| Eric B Munson | 50 | 0.10% | 3 | 0.28% |
| Lin Ming | 48 | 0.09% | 2 | 0.18% |
| Tero Kristo | 44 | 0.08% | 1 | 0.09% |
| Avi Kivity | 43 | 0.08% | 2 | 0.18% |
| Delyan Kratunov | 41 | 0.08% | 1 | 0.09% |
| Linus Torvalds (pre-git) | 41 | 0.08% | 10 | 0.92% |
| Matt Fleming | 41 | 0.08% | 4 | 0.37% |
| Mathieu J. Poirier | 39 | 0.07% | 3 | 0.28% |
| Robert Richter | 38 | 0.07% | 4 | 0.37% |
| Anton Blanchard | 36 | 0.07% | 2 | 0.18% |
| Paul E. McKenney | 35 | 0.07% | 3 | 0.28% |
| Vince Weaver | 34 | 0.06% | 2 | 0.18% |
| Thomas Richter | 34 | 0.06% | 2 | 0.18% |
| Soeren Sandmann Pedersen | 34 | 0.06% | 2 | 0.18% |
| Andrew Murray | 33 | 0.06% | 1 | 0.09% |
| Eric W. Biedermann | 33 | 0.06% | 8 | 0.74% |
| Kuan-Wei Chiu | 33 | 0.06% | 4 | 0.37% |
| haifeng.xu | 32 | 0.06% | 1 | 0.09% |
| Andrey Vagin | 32 | 0.06% | 2 | 0.18% |
| Steven Rostedt | 32 | 0.06% | 2 | 0.18% |
| Rob Herring | 30 | 0.06% | 1 | 0.09% |
| Yang Jihong | 28 | 0.05% | 4 | 0.37% |
| Davidlohr Bueso A | 24 | 0.05% | 1 | 0.09% |
| Reinette Chatre | 23 | 0.04% | 1 | 0.09% |
| Prashant Bhole | 23 | 0.04% | 1 | 0.09% |
| Aleksa Sarai | 21 | 0.04% | 2 | 0.18% |
| Yann Droneaud | 20 | 0.04% | 1 | 0.09% |
| K.Prasad | 19 | 0.04% | 2 | 0.18% |
| Andrew Morton | 17 | 0.03% | 4 | 0.37% |
| Jason Wessel | 17 | 0.03% | 1 | 0.09% |
| Madhavan Srinivasan | 17 | 0.03% | 2 | 0.18% |
| Franck Bui-Huu | 17 | 0.03% | 3 | 0.28% |
| Matthew Wilcox | 17 | 0.03% | 2 | 0.18% |
| Paul Menage | 17 | 0.03% | 2 | 0.18% |
| Will Deacon | 16 | 0.03% | 5 | 0.46% |
| Hideaki Yoshifuji / 吉藤英明 | 16 | 0.03% | 2 | 0.18% |
| David Howells | 15 | 0.03% | 2 | 0.18% |
| Hugh Dickins | 15 | 0.03% | 2 | 0.18% |
| Barret Rhoden | 14 | 0.03% | 1 | 0.09% |
| Kefeng Wang | 14 | 0.03% | 1 | 0.09% |
| Josef Bacik | 13 | 0.02% | 1 | 0.09% |
| kiyin(尹亮) | 13 | 0.02% | 1 | 0.09% |
| Linus Torvalds | 13 | 0.02% | 5 | 0.46% |
| Xiao Guangrong | 13 | 0.02% | 2 | 0.18% |
| Eugene Syromiatnikov | 12 | 0.02% | 1 | 0.09% |
| Greg Thelen | 11 | 0.02% | 1 | 0.09% |
| Ondrej Mosnáček | 11 | 0.02% | 1 | 0.09% |
| Shaohua Li | 11 | 0.02% | 1 | 0.09% |
| Arnd Bergmann | 10 | 0.02% | 1 | 0.09% |
| Jonathan Cameron | 10 | 0.02% | 1 | 0.09% |
| Kamezawa Hiroyuki | 10 | 0.02% | 1 | 0.09% |
| Christoph Lameter | 9 | 0.02% | 3 | 0.28% |
| Borislav Petkov | 9 | 0.02% | 1 | 0.09% |
| Vikas Shivappa | 8 | 0.02% | 1 | 0.09% |
| Dan Carpenter | 7 | 0.01% | 1 | 0.09% |
| Elena Reshetova | 7 | 0.01% | 3 | 0.28% |
| Tobias Tefke | 7 | 0.01% | 1 | 0.09% |
| Balbir Singh | 7 | 0.01% | 1 | 0.09% |
| Rusty Russell | 6 | 0.01% | 2 | 0.18% |
| Kajol Jain | 6 | 0.01% | 1 | 0.09% |
| Meng Xu | 6 | 0.01% | 1 | 0.09% |
| Vasily Averin | 6 | 0.01% | 1 | 0.09% |
| Benjamin Thiel | 6 | 0.01% | 1 | 0.09% |
| Gleb Natapov | 6 | 0.01% | 1 | 0.09% |
| Geliang Tang | 5 | 0.01% | 1 | 0.09% |
| Suzuki K. Poulose | 5 | 0.01% | 1 | 0.09% |
| Wei Yongjun | 5 | 0.01% | 1 | 0.09% |
| Mike Leach | 5 | 0.01% | 1 | 0.09% |
| Sandipan Das | 4 | 0.01% | 1 | 0.09% |
| Anshuman Khandual | 4 | 0.01% | 2 | 0.18% |
| Souptick Joarder | 4 | 0.01% | 2 | 0.18% |
| Haocheng Xie | 4 | 0.01% | 2 | 0.18% |
| Michel Lespinasse | 4 | 0.01% | 2 | 0.18% |
| Steven Whitehouse | 4 | 0.01% | 1 | 0.09% |
| Budimir Markovic | 4 | 0.01% | 1 | 0.09% |
| Suren Baghdasaryan | 4 | 0.01% | 1 | 0.09% |
| Dave Jiang | 4 | 0.01% | 1 | 0.09% |
| Christophe Leroy | 3 | 0.01% | 1 | 0.09% |
| Azeem Shaikh | 3 | 0.01% | 1 | 0.09% |
| Cui GaoSheng | 3 | 0.01% | 1 | 0.09% |
| Irenge Jules Bashizi | 3 | 0.01% | 1 | 0.09% |
| Tim Blechmann | 3 | 0.01% | 1 | 0.09% |
| Ian Schram | 3 | 0.01% | 1 | 0.09% |
| Kristian Högsberg | 3 | 0.01% | 1 | 0.09% |
| Zhipeng Xie | 3 | 0.01% | 1 | 0.09% |
| Cédric Le Goater | 3 | 0.01% | 1 | 0.09% |
| Alexander Graf | 3 | 0.01% | 1 | 0.09% |
| Paul Gortmaker | 3 | 0.01% | 1 | 0.09% |
| Konstantin Khlebnikov | 3 | 0.01% | 1 | 0.09% |
| Jason Baron | 2 | 0.00% | 1 | 0.09% |
| Hendrik Brueckner | 2 | 0.00% | 1 | 0.09% |
| David Hildenbrand | 2 | 0.00% | 1 | 0.09% |
| Hou Tao | 2 | 0.00% | 2 | 0.18% |
| Dmitry Torokhov | 2 | 0.00% | 1 | 0.09% |
| Leonard Crestez | 2 | 0.00% | 1 | 0.09% |
| Randy Dunlap | 2 | 0.00% | 1 | 0.09% |
| Jesper Juhl | 2 | 0.00% | 1 | 0.09% |
| Joel Granados | 2 | 0.00% | 1 | 0.09% |
| Paul Jackson | 2 | 0.00% | 1 | 0.09% |
| Mischa Jonker | 2 | 0.00% | 1 | 0.09% |
| Roy Ben Shlomo | 2 | 0.00% | 1 | 0.09% |
| Gustavo A. R. Silva | 2 | 0.00% | 1 | 0.09% |
| Jason A. Donenfeld | 2 | 0.00% | 1 | 0.09% |
| Américo Wang | 1 | 0.00% | 1 | 0.09% |
| Lai Jiangshan | 1 | 0.00% | 1 | 0.09% |
| Yinghai Lu | 1 | 0.00% | 1 | 0.09% |
| Valdis Kletnieks | 1 | 0.00% | 1 | 0.09% |
| Florian Lehner | 1 | 0.00% | 1 | 0.09% |
| Tan Xiaojun | 1 | 0.00% | 1 | 0.09% |
| Vineet Gupta | 1 | 0.00% | 1 | 0.09% |
| Xiu Jianfeng | 1 | 0.00% | 1 | 0.09% |
| David Ahern | 1 | 0.00% | 1 | 0.09% |
| Knut Petersen | 1 | 0.00% | 1 | 0.09% |
| Yanmin Zhang | 1 | 0.00% | 1 | 0.09% |
| Dave Young | 1 | 0.00% | 1 | 0.09% |
| Michael O'Farrell | 1 | 0.00% | 1 | 0.09% |
| Török Edwin | 1 | 0.00% | 1 | 0.09% |
| Octavian Purdila | 1 | 0.00% | 1 | 0.09% |
| Masahiro Yamada | 1 | 0.00% | 1 | 0.09% |
| Miklos Szeredi | 1 | 0.00% | 1 | 0.09% |
| Mike Galbraith | 1 | 0.00% | 1 | 0.09% |
| Total | 52602 | 1088 |
// SPDX-License-Identifier: GPL-2.0 /* * Performance events core code: * * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> */ #include <linux/fs.h> #include <linux/mm.h> #include <linux/cpu.h> #include <linux/smp.h> #include <linux/idr.h> #include <linux/file.h> #include <linux/poll.h> #include <linux/slab.h> #include <linux/hash.h> #include <linux/tick.h> #include <linux/sysfs.h> #include <linux/dcache.h> #include <linux/percpu.h> #include <linux/ptrace.h> #include <linux/reboot.h> #include <linux/vmstat.h> #include <linux/device.h> #include <linux/export.h> #include <linux/vmalloc.h> #include <linux/hardirq.h> #include <linux/hugetlb.h> #include <linux/rculist.h> #include <linux/uaccess.h> #include <linux/syscalls.h> #include <linux/anon_inodes.h> #include <linux/kernel_stat.h> #include <linux/cgroup.h> #include <linux/perf_event.h> #include <linux/trace_events.h> #include <linux/hw_breakpoint.h> #include <linux/mm_types.h> #include <linux/module.h> #include <linux/mman.h> #include <linux/compat.h> #include <linux/bpf.h> #include <linux/filter.h> #include <linux/namei.h> #include <linux/parser.h> #include <linux/sched/clock.h> #include <linux/sched/mm.h> #include <linux/proc_ns.h> #include <linux/mount.h> #include <linux/min_heap.h> #include <linux/highmem.h> #include <linux/pgtable.h> #include <linux/buildid.h> #include <linux/task_work.h> #include "internal.h" #include <asm/irq_regs.h> typedef int (*remote_function_f)(void *); struct remote_function_call { struct task_struct *p; remote_function_f func; void *info; int ret; }; static void remote_function(void *data) { struct remote_function_call *tfc = data; struct task_struct *p = tfc->p; if (p) { /* -EAGAIN */ if (task_cpu(p) != smp_processor_id()) return; /* * Now that we're on right CPU with IRQs disabled, we can test * if we hit the right task without races. */ tfc->ret = -ESRCH; /* No such (running) process */ if (p != current) return; } tfc->ret = tfc->func(tfc->info); } /** * task_function_call - call a function on the cpu on which a task runs * @p: the task to evaluate * @func: the function to be called * @info: the function call argument * * Calls the function @func when the task is currently running. This might * be on the current CPU, which just calls the function directly. This will * retry due to any failures in smp_call_function_single(), such as if the * task_cpu() goes offline concurrently. * * returns @func return value or -ESRCH or -ENXIO when the process isn't running */ static int task_function_call(struct task_struct *p, remote_function_f func, void *info) { struct remote_function_call data = { .p = p, .func = func, .info = info, .ret = -EAGAIN, }; int ret; for (;;) { ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); if (!ret) ret = data.ret; if (ret != -EAGAIN) break; cond_resched(); } return ret; } /** * cpu_function_call - call a function on the cpu * @cpu: target cpu to queue this function * @func: the function to be called * @info: the function call argument * * Calls the function @func on the remote cpu. * * returns: @func return value or -ENXIO when the cpu is offline */ static int cpu_function_call(int cpu, remote_function_f func, void *info) { struct remote_function_call data = { .p = NULL, .func = func, .info = info, .ret = -ENXIO, /* No such CPU */ }; smp_call_function_single(cpu, remote_function, &data, 1); return data.ret; } static void perf_ctx_lock(struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { raw_spin_lock(&cpuctx->ctx.lock); if (ctx) raw_spin_lock(&ctx->lock); } static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { if (ctx) raw_spin_unlock(&ctx->lock); raw_spin_unlock(&cpuctx->ctx.lock); } #define TASK_TOMBSTONE ((void *)-1L) static bool is_kernel_event(struct perf_event *event) { return READ_ONCE(event->owner) == TASK_TOMBSTONE; } static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context); struct perf_event_context *perf_cpu_task_ctx(void) { lockdep_assert_irqs_disabled(); return this_cpu_ptr(&perf_cpu_context)->task_ctx; } /* * On task ctx scheduling... * * When !ctx->nr_events a task context will not be scheduled. This means * we can disable the scheduler hooks (for performance) without leaving * pending task ctx state. * * This however results in two special cases: * * - removing the last event from a task ctx; this is relatively straight * forward and is done in __perf_remove_from_context. * * - adding the first event to a task ctx; this is tricky because we cannot * rely on ctx->is_active and therefore cannot use event_function_call(). * See perf_install_in_context(). * * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. */ typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, struct perf_event_context *, void *); struct event_function_struct { struct perf_event *event; event_f func; void *data; }; static int event_function(void *info) { struct event_function_struct *efs = info; struct perf_event *event = efs->event; struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_context *task_ctx = cpuctx->task_ctx; int ret = 0; lockdep_assert_irqs_disabled(); perf_ctx_lock(cpuctx, task_ctx); /* * Since we do the IPI call without holding ctx->lock things can have * changed, double check we hit the task we set out to hit. */ if (ctx->task) { if (ctx->task != current) { ret = -ESRCH; goto unlock; } /* * We only use event_function_call() on established contexts, * and event_function() is only ever called when active (or * rather, we'll have bailed in task_function_call() or the * above ctx->task != current test), therefore we must have * ctx->is_active here. */ WARN_ON_ONCE(!ctx->is_active); /* * And since we have ctx->is_active, cpuctx->task_ctx must * match. */ WARN_ON_ONCE(task_ctx != ctx); } else { WARN_ON_ONCE(&cpuctx->ctx != ctx); } efs->func(event, cpuctx, ctx, efs->data); unlock: perf_ctx_unlock(cpuctx, task_ctx); return ret; } static void event_function_call(struct perf_event *event, event_f func, void *data) { struct perf_event_context *ctx = event->ctx; struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ struct event_function_struct efs = { .event = event, .func = func, .data = data, }; if (!event->parent) { /* * If this is a !child event, we must hold ctx::mutex to * stabilize the event->ctx relation. See * perf_event_ctx_lock(). */ lockdep_assert_held(&ctx->mutex); } if (!task) { cpu_function_call(event->cpu, event_function, &efs); return; } if (task == TASK_TOMBSTONE) return; again: if (!task_function_call(task, event_function, &efs)) return; raw_spin_lock_irq(&ctx->lock); /* * Reload the task pointer, it might have been changed by * a concurrent perf_event_context_sched_out(). */ task = ctx->task; if (task == TASK_TOMBSTONE) { raw_spin_unlock_irq(&ctx->lock); return; } if (ctx->is_active) { raw_spin_unlock_irq(&ctx->lock); goto again; } func(event, NULL, ctx, data); raw_spin_unlock_irq(&ctx->lock); } /* * Similar to event_function_call() + event_function(), but hard assumes IRQs * are already disabled and we're on the right CPU. */ static void event_function_local(struct perf_event *event, event_f func, void *data) { struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct task_struct *task = READ_ONCE(ctx->task); struct perf_event_context *task_ctx = NULL; lockdep_assert_irqs_disabled(); if (task) { if (task == TASK_TOMBSTONE) return; task_ctx = ctx; } perf_ctx_lock(cpuctx, task_ctx); task = ctx->task; if (task == TASK_TOMBSTONE) goto unlock; if (task) { /* * We must be either inactive or active and the right task, * otherwise we're screwed, since we cannot IPI to somewhere * else. */ if (ctx->is_active) { if (WARN_ON_ONCE(task != current)) goto unlock; if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) goto unlock; } } else { WARN_ON_ONCE(&cpuctx->ctx != ctx); } func(event, cpuctx, ctx, data); unlock: perf_ctx_unlock(cpuctx, task_ctx); } #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ PERF_FLAG_FD_OUTPUT |\ PERF_FLAG_PID_CGROUP |\ PERF_FLAG_FD_CLOEXEC) /* * branch priv levels that need permission checks */ #define PERF_SAMPLE_BRANCH_PERM_PLM \ (PERF_SAMPLE_BRANCH_KERNEL |\ PERF_SAMPLE_BRANCH_HV) enum event_type_t { EVENT_FLEXIBLE = 0x1, EVENT_PINNED = 0x2, EVENT_TIME = 0x4, /* see ctx_resched() for details */ EVENT_CPU = 0x8, EVENT_CGROUP = 0x10, EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, }; /* * perf_sched_events : >0 events exist */ static void perf_sched_delayed(struct work_struct *work); DEFINE_STATIC_KEY_FALSE(perf_sched_events); static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); static DEFINE_MUTEX(perf_sched_mutex); static atomic_t perf_sched_count; static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); static atomic_t nr_mmap_events __read_mostly; static atomic_t nr_comm_events __read_mostly; static atomic_t nr_namespaces_events __read_mostly; static atomic_t nr_task_events __read_mostly; static atomic_t nr_freq_events __read_mostly; static atomic_t nr_switch_events __read_mostly; static atomic_t nr_ksymbol_events __read_mostly; static atomic_t nr_bpf_events __read_mostly; static atomic_t nr_cgroup_events __read_mostly; static atomic_t nr_text_poke_events __read_mostly; static atomic_t nr_build_id_events __read_mostly; static LIST_HEAD(pmus); static DEFINE_MUTEX(pmus_lock); static struct srcu_struct pmus_srcu; static cpumask_var_t perf_online_mask; static struct kmem_cache *perf_event_cache; /* * perf event paranoia level: * -1 - not paranoid at all * 0 - disallow raw tracepoint access for unpriv * 1 - disallow cpu events for unpriv * 2 - disallow kernel profiling for unpriv */ int sysctl_perf_event_paranoid __read_mostly = 2; /* Minimum for 512 kiB + 1 user control page */ int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ /* * max perf event sample rate */ #define DEFAULT_MAX_SAMPLE_RATE 100000 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) #define DEFAULT_CPU_TIME_MAX_PERCENT 25 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; static int perf_sample_allowed_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; static void update_perf_cpu_limits(void) { u64 tmp = perf_sample_period_ns; tmp *= sysctl_perf_cpu_time_max_percent; tmp = div_u64(tmp, 100); if (!tmp) tmp = 1; WRITE_ONCE(perf_sample_allowed_ns, tmp); } static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc); int perf_event_max_sample_rate_handler(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { int ret; int perf_cpu = sysctl_perf_cpu_time_max_percent; /* * If throttling is disabled don't allow the write: */ if (write && (perf_cpu == 100 || perf_cpu == 0)) return -EINVAL; ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (ret || !write) return ret; max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; update_perf_cpu_limits(); return 0; } int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; int perf_cpu_time_max_percent_handler(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (ret || !write) return ret; if (sysctl_perf_cpu_time_max_percent == 100 || sysctl_perf_cpu_time_max_percent == 0) { printk(KERN_WARNING "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); WRITE_ONCE(perf_sample_allowed_ns, 0); } else { update_perf_cpu_limits(); } return 0; } /* * perf samples are done in some very critical code paths (NMIs). * If they take too much CPU time, the system can lock up and not * get any real work done. This will drop the sample rate when * we detect that events are taking too long. */ #define NR_ACCUMULATED_SAMPLES 128 static DEFINE_PER_CPU(u64, running_sample_length); static u64 __report_avg; static u64 __report_allowed; static void perf_duration_warn(struct irq_work *w) { printk_ratelimited(KERN_INFO "perf: interrupt took too long (%lld > %lld), lowering " "kernel.perf_event_max_sample_rate to %d\n", __report_avg, __report_allowed, sysctl_perf_event_sample_rate); } static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); void perf_sample_event_took(u64 sample_len_ns) { u64 max_len = READ_ONCE(perf_sample_allowed_ns); u64 running_len; u64 avg_len; u32 max; if (max_len == 0) return; /* Decay the counter by 1 average sample. */ running_len = __this_cpu_read(running_sample_length); running_len -= running_len/NR_ACCUMULATED_SAMPLES; running_len += sample_len_ns; __this_cpu_write(running_sample_length, running_len); /* * Note: this will be biased artificially low until we have * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us * from having to maintain a count. */ avg_len = running_len/NR_ACCUMULATED_SAMPLES; if (avg_len <= max_len) return; __report_avg = avg_len; __report_allowed = max_len; /* * Compute a throttle threshold 25% below the current duration. */ avg_len += avg_len / 4; max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; if (avg_len < max) max /= (u32)avg_len; else max = 1; WRITE_ONCE(perf_sample_allowed_ns, avg_len); WRITE_ONCE(max_samples_per_tick, max); sysctl_perf_event_sample_rate = max * HZ; perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; if (!irq_work_queue(&perf_duration_work)) { early_printk("perf: interrupt took too long (%lld > %lld), lowering " "kernel.perf_event_max_sample_rate to %d\n", __report_avg, __report_allowed, sysctl_perf_event_sample_rate); } } static atomic64_t perf_event_id; static void update_context_time(struct perf_event_context *ctx); static u64 perf_event_time(struct perf_event *event); void __weak perf_event_print_debug(void) { } static inline u64 perf_clock(void) { return local_clock(); } static inline u64 perf_event_clock(struct perf_event *event) { return event->clock(); } /* * State based event timekeeping... * * The basic idea is to use event->state to determine which (if any) time * fields to increment with the current delta. This means we only need to * update timestamps when we change state or when they are explicitly requested * (read). * * Event groups make things a little more complicated, but not terribly so. The * rules for a group are that if the group leader is OFF the entire group is * OFF, irrespective of what the group member states are. This results in * __perf_effective_state(). * * A further ramification is that when a group leader flips between OFF and * !OFF, we need to update all group member times. * * * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we * need to make sure the relevant context time is updated before we try and * update our timestamps. */ static __always_inline enum perf_event_state __perf_effective_state(struct perf_event *event) { struct perf_event *leader = event->group_leader; if (leader->state <= PERF_EVENT_STATE_OFF) return leader->state; return event->state; } static __always_inline void __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running) { enum perf_event_state state = __perf_effective_state(event); u64 delta = now - event->tstamp; *enabled = event->total_time_enabled; if (state >= PERF_EVENT_STATE_INACTIVE) *enabled += delta; *running = event->total_time_running; if (state >= PERF_EVENT_STATE_ACTIVE) *running += delta; } static void perf_event_update_time(struct perf_event *event) { u64 now = perf_event_time(event); __perf_update_times(event, now, &event->total_time_enabled, &event->total_time_running); event->tstamp = now; } static void perf_event_update_sibling_time(struct perf_event *leader) { struct perf_event *sibling; for_each_sibling_event(sibling, leader) perf_event_update_time(sibling); } static void perf_event_set_state(struct perf_event *event, enum perf_event_state state) { if (event->state == state) return; perf_event_update_time(event); /* * If a group leader gets enabled/disabled all its siblings * are affected too. */ if ((event->state < 0) ^ (state < 0)) perf_event_update_sibling_time(event); WRITE_ONCE(event->state, state); } /* * UP store-release, load-acquire */ #define __store_release(ptr, val) \ do { \ barrier(); \ WRITE_ONCE(*(ptr), (val)); \ } while (0) #define __load_acquire(ptr) \ ({ \ __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \ barrier(); \ ___p; \ }) static void perf_ctx_disable(struct perf_event_context *ctx, bool cgroup) { struct perf_event_pmu_context *pmu_ctx; list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { if (cgroup && !pmu_ctx->nr_cgroups) continue; perf_pmu_disable(pmu_ctx->pmu); } } static void perf_ctx_enable(struct perf_event_context *ctx, bool cgroup) { struct perf_event_pmu_context *pmu_ctx; list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { if (cgroup && !pmu_ctx->nr_cgroups) continue; perf_pmu_enable(pmu_ctx->pmu); } } static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type); static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type); #ifdef CONFIG_CGROUP_PERF static inline bool perf_cgroup_match(struct perf_event *event) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); /* @event doesn't care about cgroup */ if (!event->cgrp) return true; /* wants specific cgroup scope but @cpuctx isn't associated with any */ if (!cpuctx->cgrp) return false; /* * Cgroup scoping is recursive. An event enabled for a cgroup is * also enabled for all its descendant cgroups. If @cpuctx's * cgroup is a descendant of @event's (the test covers identity * case), it's a match. */ return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, event->cgrp->css.cgroup); } static inline void perf_detach_cgroup(struct perf_event *event) { css_put(&event->cgrp->css); event->cgrp = NULL; } static inline int is_cgroup_event(struct perf_event *event) { return event->cgrp != NULL; } static inline u64 perf_cgroup_event_time(struct perf_event *event) { struct perf_cgroup_info *t; t = per_cpu_ptr(event->cgrp->info, event->cpu); return t->time; } static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) { struct perf_cgroup_info *t; t = per_cpu_ptr(event->cgrp->info, event->cpu); if (!__load_acquire(&t->active)) return t->time; now += READ_ONCE(t->timeoffset); return now; } static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv) { if (adv) info->time += now - info->timestamp; info->timestamp = now; /* * see update_context_time() */ WRITE_ONCE(info->timeoffset, info->time - info->timestamp); } static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final) { struct perf_cgroup *cgrp = cpuctx->cgrp; struct cgroup_subsys_state *css; struct perf_cgroup_info *info; if (cgrp) { u64 now = perf_clock(); for (css = &cgrp->css; css; css = css->parent) { cgrp = container_of(css, struct perf_cgroup, css); info = this_cpu_ptr(cgrp->info); __update_cgrp_time(info, now, true); if (final) __store_release(&info->active, 0); } } } static inline void update_cgrp_time_from_event(struct perf_event *event) { struct perf_cgroup_info *info; /* * ensure we access cgroup data only when needed and * when we know the cgroup is pinned (css_get) */ if (!is_cgroup_event(event)) return; info = this_cpu_ptr(event->cgrp->info); /* * Do not update time when cgroup is not active */ if (info->active) __update_cgrp_time(info, perf_clock(), true); } static inline void perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx) { struct perf_event_context *ctx = &cpuctx->ctx; struct perf_cgroup *cgrp = cpuctx->cgrp; struct perf_cgroup_info *info; struct cgroup_subsys_state *css; /* * ctx->lock held by caller * ensure we do not access cgroup data * unless we have the cgroup pinned (css_get) */ if (!cgrp) return; WARN_ON_ONCE(!ctx->nr_cgroups); for (css = &cgrp->css; css; css = css->parent) { cgrp = container_of(css, struct perf_cgroup, css); info = this_cpu_ptr(cgrp->info); __update_cgrp_time(info, ctx->timestamp, false); __store_release(&info->active, 1); } } /* * reschedule events based on the cgroup constraint of task. */ static void perf_cgroup_switch(struct task_struct *task) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_cgroup *cgrp; /* * cpuctx->cgrp is set when the first cgroup event enabled, * and is cleared when the last cgroup event disabled. */ if (READ_ONCE(cpuctx->cgrp) == NULL) return; WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); cgrp = perf_cgroup_from_task(task, NULL); if (READ_ONCE(cpuctx->cgrp) == cgrp) return; perf_ctx_lock(cpuctx, cpuctx->task_ctx); perf_ctx_disable(&cpuctx->ctx, true); ctx_sched_out(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP); /* * must not be done before ctxswout due * to update_cgrp_time_from_cpuctx() in * ctx_sched_out() */ cpuctx->cgrp = cgrp; /* * set cgrp before ctxsw in to allow * perf_cgroup_set_timestamp() in ctx_sched_in() * to not have to pass task around */ ctx_sched_in(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP); perf_ctx_enable(&cpuctx->ctx, true); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); } static int perf_cgroup_ensure_storage(struct perf_event *event, struct cgroup_subsys_state *css) { struct perf_cpu_context *cpuctx; struct perf_event **storage; int cpu, heap_size, ret = 0; /* * Allow storage to have sufficient space for an iterator for each * possibly nested cgroup plus an iterator for events with no cgroup. */ for (heap_size = 1; css; css = css->parent) heap_size++; for_each_possible_cpu(cpu) { cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); if (heap_size <= cpuctx->heap_size) continue; storage = kmalloc_node(heap_size * sizeof(struct perf_event *), GFP_KERNEL, cpu_to_node(cpu)); if (!storage) { ret = -ENOMEM; break; } raw_spin_lock_irq(&cpuctx->ctx.lock); if (cpuctx->heap_size < heap_size) { swap(cpuctx->heap, storage); if (storage == cpuctx->heap_default) storage = NULL; cpuctx->heap_size = heap_size; } raw_spin_unlock_irq(&cpuctx->ctx.lock); kfree(storage); } return ret; } static inline int perf_cgroup_connect(int fd, struct perf_event *event, struct perf_event_attr *attr, struct perf_event *group_leader) { struct perf_cgroup *cgrp; struct cgroup_subsys_state *css; struct fd f = fdget(fd); int ret = 0; if (!f.file) return -EBADF; css = css_tryget_online_from_dir(f.file->f_path.dentry, &perf_event_cgrp_subsys); if (IS_ERR(css)) { ret = PTR_ERR(css); goto out; } ret = perf_cgroup_ensure_storage(event, css); if (ret) goto out; cgrp = container_of(css, struct perf_cgroup, css); event->cgrp = cgrp; /* * all events in a group must monitor * the same cgroup because a task belongs * to only one perf cgroup at a time */ if (group_leader && group_leader->cgrp != cgrp) { perf_detach_cgroup(event); ret = -EINVAL; } out: fdput(f); return ret; } static inline void perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) { struct perf_cpu_context *cpuctx; if (!is_cgroup_event(event)) return; event->pmu_ctx->nr_cgroups++; /* * Because cgroup events are always per-cpu events, * @ctx == &cpuctx->ctx. */ cpuctx = container_of(ctx, struct perf_cpu_context, ctx); if (ctx->nr_cgroups++) return; cpuctx->cgrp = perf_cgroup_from_task(current, ctx); } static inline void perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) { struct perf_cpu_context *cpuctx; if (!is_cgroup_event(event)) return; event->pmu_ctx->nr_cgroups--; /* * Because cgroup events are always per-cpu events, * @ctx == &cpuctx->ctx. */ cpuctx = container_of(ctx, struct perf_cpu_context, ctx); if (--ctx->nr_cgroups) return; cpuctx->cgrp = NULL; } #else /* !CONFIG_CGROUP_PERF */ static inline bool perf_cgroup_match(struct perf_event *event) { return true; } static inline void perf_detach_cgroup(struct perf_event *event) {} static inline int is_cgroup_event(struct perf_event *event) { return 0; } static inline void update_cgrp_time_from_event(struct perf_event *event) { } static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final) { } static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, struct perf_event_attr *attr, struct perf_event *group_leader) { return -EINVAL; } static inline void perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx) { } static inline u64 perf_cgroup_event_time(struct perf_event *event) { return 0; } static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) { return 0; } static inline void perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) { } static inline void perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) { } static void perf_cgroup_switch(struct task_struct *task) { } #endif /* * set default to be dependent on timer tick just * like original code */ #define PERF_CPU_HRTIMER (1000 / HZ) /* * function must be called with interrupts disabled */ static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) { struct perf_cpu_pmu_context *cpc; bool rotations; lockdep_assert_irqs_disabled(); cpc = container_of(hr, struct perf_cpu_pmu_context, hrtimer); rotations = perf_rotate_context(cpc); raw_spin_lock(&cpc->hrtimer_lock); if (rotations) hrtimer_forward_now(hr, cpc->hrtimer_interval); else cpc->hrtimer_active = 0; raw_spin_unlock(&cpc->hrtimer_lock); return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; } static void __perf_mux_hrtimer_init(struct perf_cpu_pmu_context *cpc, int cpu) { struct hrtimer *timer = &cpc->hrtimer; struct pmu *pmu = cpc->epc.pmu; u64 interval; /* * check default is sane, if not set then force to * default interval (1/tick) */ interval = pmu->hrtimer_interval_ms; if (interval < 1) interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); raw_spin_lock_init(&cpc->hrtimer_lock); hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); timer->function = perf_mux_hrtimer_handler; } static int perf_mux_hrtimer_restart(struct perf_cpu_pmu_context *cpc) { struct hrtimer *timer = &cpc->hrtimer; unsigned long flags; raw_spin_lock_irqsave(&cpc->hrtimer_lock, flags); if (!cpc->hrtimer_active) { cpc->hrtimer_active = 1; hrtimer_forward_now(timer, cpc->hrtimer_interval); hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD); } raw_spin_unlock_irqrestore(&cpc->hrtimer_lock, flags); return 0; } static int perf_mux_hrtimer_restart_ipi(void *arg) { return perf_mux_hrtimer_restart(arg); } void perf_pmu_disable(struct pmu *pmu) { int *count = this_cpu_ptr(pmu->pmu_disable_count); if (!(*count)++) pmu->pmu_disable(pmu); } void perf_pmu_enable(struct pmu *pmu) { int *count = this_cpu_ptr(pmu->pmu_disable_count); if (!--(*count)) pmu->pmu_enable(pmu); } static void perf_assert_pmu_disabled(struct pmu *pmu) { WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0); } static void get_ctx(struct perf_event_context *ctx) { refcount_inc(&ctx->refcount); } static void *alloc_task_ctx_data(struct pmu *pmu) { if (pmu->task_ctx_cache) return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL); return NULL; } static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data) { if (pmu->task_ctx_cache && task_ctx_data) kmem_cache_free(pmu->task_ctx_cache, task_ctx_data); } static void free_ctx(struct rcu_head *head) { struct perf_event_context *ctx; ctx = container_of(head, struct perf_event_context, rcu_head); kfree(ctx); } static void put_ctx(struct perf_event_context *ctx) { if (refcount_dec_and_test(&ctx->refcount)) { if (ctx->parent_ctx) put_ctx(ctx->parent_ctx); if (ctx->task && ctx->task != TASK_TOMBSTONE) put_task_struct(ctx->task); call_rcu(&ctx->rcu_head, free_ctx); } } /* * Because of perf_event::ctx migration in sys_perf_event_open::move_group and * perf_pmu_migrate_context() we need some magic. * * Those places that change perf_event::ctx will hold both * perf_event_ctx::mutex of the 'old' and 'new' ctx value. * * Lock ordering is by mutex address. There are two other sites where * perf_event_context::mutex nests and those are: * * - perf_event_exit_task_context() [ child , 0 ] * perf_event_exit_event() * put_event() [ parent, 1 ] * * - perf_event_init_context() [ parent, 0 ] * inherit_task_group() * inherit_group() * inherit_event() * perf_event_alloc() * perf_init_event() * perf_try_init_event() [ child , 1 ] * * While it appears there is an obvious deadlock here -- the parent and child * nesting levels are inverted between the two. This is in fact safe because * life-time rules separate them. That is an exiting task cannot fork, and a * spawning task cannot (yet) exit. * * But remember that these are parent<->child context relations, and * migration does not affect children, therefore these two orderings should not * interact. * * The change in perf_event::ctx does not affect children (as claimed above) * because the sys_perf_event_open() case will install a new event and break * the ctx parent<->child relation, and perf_pmu_migrate_context() is only * concerned with cpuctx and that doesn't have children. * * The places that change perf_event::ctx will issue: * * perf_remove_from_context(); * synchronize_rcu(); * perf_install_in_context(); * * to affect the change. The remove_from_context() + synchronize_rcu() should * quiesce the event, after which we can install it in the new location. This * means that only external vectors (perf_fops, prctl) can perturb the event * while in transit. Therefore all such accessors should also acquire * perf_event_context::mutex to serialize against this. * * However; because event->ctx can change while we're waiting to acquire * ctx->mutex we must be careful and use the below perf_event_ctx_lock() * function. * * Lock order: * exec_update_lock * task_struct::perf_event_mutex * perf_event_context::mutex * perf_event::child_mutex; * perf_event_context::lock * mmap_lock * perf_event::mmap_mutex * perf_buffer::aux_mutex * perf_addr_filters_head::lock * * cpu_hotplug_lock * pmus_lock * cpuctx->mutex / perf_event_context::mutex */ static struct perf_event_context * perf_event_ctx_lock_nested(struct perf_event *event, int nesting) { struct perf_event_context *ctx; again: rcu_read_lock(); ctx = READ_ONCE(event->ctx); if (!refcount_inc_not_zero(&ctx->refcount)) { rcu_read_unlock(); goto again; } rcu_read_unlock(); mutex_lock_nested(&ctx->mutex, nesting); if (event->ctx != ctx) { mutex_unlock(&ctx->mutex); put_ctx(ctx); goto again; } return ctx; } static inline struct perf_event_context * perf_event_ctx_lock(struct perf_event *event) { return perf_event_ctx_lock_nested(event, 0); } static void perf_event_ctx_unlock(struct perf_event *event, struct perf_event_context *ctx) { mutex_unlock(&ctx->mutex); put_ctx(ctx); } /* * This must be done under the ctx->lock, such as to serialize against * context_equiv(), therefore we cannot call put_ctx() since that might end up * calling scheduler related locks and ctx->lock nests inside those. */ static __must_check struct perf_event_context * unclone_ctx(struct perf_event_context *ctx) { struct perf_event_context *parent_ctx = ctx->parent_ctx; lockdep_assert_held(&ctx->lock); if (parent_ctx) ctx->parent_ctx = NULL; ctx->generation++; return parent_ctx; } static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, enum pid_type type) { u32 nr; /* * only top level events have the pid namespace they were created in */ if (event->parent) event = event->parent; nr = __task_pid_nr_ns(p, type, event->ns); /* avoid -1 if it is idle thread or runs in another ns */ if (!nr && !pid_alive(p)) nr = -1; return nr; } static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) { return perf_event_pid_type(event, p, PIDTYPE_TGID); } static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) { return perf_event_pid_type(event, p, PIDTYPE_PID); } /* * If we inherit events we want to return the parent event id * to userspace. */ static u64 primary_event_id(struct perf_event *event) { u64 id = event->id; if (event->parent) id = event->parent->id; return id; } /* * Get the perf_event_context for a task and lock it. * * This has to cope with the fact that until it is locked, * the context could get moved to another task. */ static struct perf_event_context * perf_lock_task_context(struct task_struct *task, unsigned long *flags) { struct perf_event_context *ctx; retry: /* * One of the few rules of preemptible RCU is that one cannot do * rcu_read_unlock() while holding a scheduler (or nested) lock when * part of the read side critical section was irqs-enabled -- see * rcu_read_unlock_special(). * * Since ctx->lock nests under rq->lock we must ensure the entire read * side critical section has interrupts disabled. */ local_irq_save(*flags); rcu_read_lock(); ctx = rcu_dereference(task->perf_event_ctxp); if (ctx) { /* * If this context is a clone of another, it might * get swapped for another underneath us by * perf_event_task_sched_out, though the * rcu_read_lock() protects us from any context * getting freed. Lock the context and check if it * got swapped before we could get the lock, and retry * if so. If we locked the right context, then it * can't get swapped on us any more. */ raw_spin_lock(&ctx->lock); if (ctx != rcu_dereference(task->perf_event_ctxp)) { raw_spin_unlock(&ctx->lock); rcu_read_unlock(); local_irq_restore(*flags); goto retry; } if (ctx->task == TASK_TOMBSTONE || !refcount_inc_not_zero(&ctx->refcount)) { raw_spin_unlock(&ctx->lock); ctx = NULL; } else { WARN_ON_ONCE(ctx->task != task); } } rcu_read_unlock(); if (!ctx) local_irq_restore(*flags); return ctx; } /* * Get the context for a task and increment its pin_count so it * can't get swapped to another task. This also increments its * reference count so that the context can't get freed. */ static struct perf_event_context * perf_pin_task_context(struct task_struct *task) { struct perf_event_context *ctx; unsigned long flags; ctx = perf_lock_task_context(task, &flags); if (ctx) { ++ctx->pin_count; raw_spin_unlock_irqrestore(&ctx->lock, flags); } return ctx; } static void perf_unpin_context(struct perf_event_context *ctx) { unsigned long flags; raw_spin_lock_irqsave(&ctx->lock, flags); --ctx->pin_count; raw_spin_unlock_irqrestore(&ctx->lock, flags); } /* * Update the record of the current time in a context. */ static void __update_context_time(struct perf_event_context *ctx, bool adv) { u64 now = perf_clock(); lockdep_assert_held(&ctx->lock); if (adv) ctx->time += now - ctx->timestamp; ctx->timestamp = now; /* * The above: time' = time + (now - timestamp), can be re-arranged * into: time` = now + (time - timestamp), which gives a single value * offset to compute future time without locks on. * * See perf_event_time_now(), which can be used from NMI context where * it's (obviously) not possible to acquire ctx->lock in order to read * both the above values in a consistent manner. */ WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp); } static void update_context_time(struct perf_event_context *ctx) { __update_context_time(ctx, true); } static u64 perf_event_time(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; if (unlikely(!ctx)) return 0; if (is_cgroup_event(event)) return perf_cgroup_event_time(event); return ctx->time; } static u64 perf_event_time_now(struct perf_event *event, u64 now) { struct perf_event_context *ctx = event->ctx; if (unlikely(!ctx)) return 0; if (is_cgroup_event(event)) return perf_cgroup_event_time_now(event, now); if (!(__load_acquire(&ctx->is_active) & EVENT_TIME)) return ctx->time; now += READ_ONCE(ctx->timeoffset); return now; } static enum event_type_t get_event_type(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; enum event_type_t event_type; lockdep_assert_held(&ctx->lock); /* * It's 'group type', really, because if our group leader is * pinned, so are we. */ if (event->group_leader != event) event = event->group_leader; event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; if (!ctx->task) event_type |= EVENT_CPU; return event_type; } /* * Helper function to initialize event group nodes. */ static void init_event_group(struct perf_event *event) { RB_CLEAR_NODE(&event->group_node); event->group_index = 0; } /* * Extract pinned or flexible groups from the context * based on event attrs bits. */ static struct perf_event_groups * get_event_groups(struct perf_event *event, struct perf_event_context *ctx) { if (event->attr.pinned) return &ctx->pinned_groups; else return &ctx->flexible_groups; } /* * Helper function to initializes perf_event_group trees. */ static void perf_event_groups_init(struct perf_event_groups *groups) { groups->tree = RB_ROOT; groups->index = 0; } static inline struct cgroup *event_cgroup(const struct perf_event *event) { struct cgroup *cgroup = NULL; #ifdef CONFIG_CGROUP_PERF if (event->cgrp) cgroup = event->cgrp->css.cgroup; #endif return cgroup; } /* * Compare function for event groups; * * Implements complex key that first sorts by CPU and then by virtual index * which provides ordering when rotating groups for the same CPU. */ static __always_inline int perf_event_groups_cmp(const int left_cpu, const struct pmu *left_pmu, const struct cgroup *left_cgroup, const u64 left_group_index, const struct perf_event *right) { if (left_cpu < right->cpu) return -1; if (left_cpu > right->cpu) return 1; if (left_pmu) { if (left_pmu < right->pmu_ctx->pmu) return -1; if (left_pmu > right->pmu_ctx->pmu) return 1; } #ifdef CONFIG_CGROUP_PERF { const struct cgroup *right_cgroup = event_cgroup(right); if (left_cgroup != right_cgroup) { if (!left_cgroup) { /* * Left has no cgroup but right does, no * cgroups come first. */ return -1; } if (!right_cgroup) { /* * Right has no cgroup but left does, no * cgroups come first. */ return 1; } /* Two dissimilar cgroups, order by id. */ if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup)) return -1; return 1; } } #endif if (left_group_index < right->group_index) return -1; if (left_group_index > right->group_index) return 1; return 0; } #define __node_2_pe(node) \ rb_entry((node), struct perf_event, group_node) static inline bool __group_less(struct rb_node *a, const struct rb_node *b) { struct perf_event *e = __node_2_pe(a); return perf_event_groups_cmp(e->cpu, e->pmu_ctx->pmu, event_cgroup(e), e->group_index, __node_2_pe(b)) < 0; } struct __group_key { int cpu; struct pmu *pmu; struct cgroup *cgroup; }; static inline int __group_cmp(const void *key, const struct rb_node *node) { const struct __group_key *a = key; const struct perf_event *b = __node_2_pe(node); /* partial/subtree match: @cpu, @pmu, @cgroup; ignore: @group_index */ return perf_event_groups_cmp(a->cpu, a->pmu, a->cgroup, b->group_index, b); } static inline int __group_cmp_ignore_cgroup(const void *key, const struct rb_node *node) { const struct __group_key *a = key; const struct perf_event *b = __node_2_pe(node); /* partial/subtree match: @cpu, @pmu, ignore: @cgroup, @group_index */ return perf_event_groups_cmp(a->cpu, a->pmu, event_cgroup(b), b->group_index, b); } /* * Insert @event into @groups' tree; using * {@event->cpu, @event->pmu_ctx->pmu, event_cgroup(@event), ++@groups->index} * as key. This places it last inside the {cpu,pmu,cgroup} subtree. */ static void perf_event_groups_insert(struct perf_event_groups *groups, struct perf_event *event) { event->group_index = ++groups->index; rb_add(&event->group_node, &groups->tree, __group_less); } /* * Helper function to insert event into the pinned or flexible groups. */ static void add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event_groups *groups; groups = get_event_groups(event, ctx); perf_event_groups_insert(groups, event); } /* * Delete a group from a tree. */ static void perf_event_groups_delete(struct perf_event_groups *groups, struct perf_event *event) { WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) || RB_EMPTY_ROOT(&groups->tree)); rb_erase(&event->group_node, &groups->tree); init_event_group(event); } /* * Helper function to delete event from its groups. */ static void del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event_groups *groups; groups = get_event_groups(event, ctx); perf_event_groups_delete(groups, event); } /* * Get the leftmost event in the {cpu,pmu,cgroup} subtree. */ static struct perf_event * perf_event_groups_first(struct perf_event_groups *groups, int cpu, struct pmu *pmu, struct cgroup *cgrp) { struct __group_key key = { .cpu = cpu, .pmu = pmu, .cgroup = cgrp, }; struct rb_node *node; node = rb_find_first(&key, &groups->tree, __group_cmp); if (node) return __node_2_pe(node); return NULL; } static struct perf_event * perf_event_groups_next(struct perf_event *event, struct pmu *pmu) { struct __group_key key = { .cpu = event->cpu, .pmu = pmu, .cgroup = event_cgroup(event), }; struct rb_node *next; next = rb_next_match(&key, &event->group_node, __group_cmp); if (next) return __node_2_pe(next); return NULL; } #define perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) \ for (event = perf_event_groups_first(groups, cpu, pmu, NULL); \ event; event = perf_event_groups_next(event, pmu)) /* * Iterate through the whole groups tree. */ #define perf_event_groups_for_each(event, groups) \ for (event = rb_entry_safe(rb_first(&((groups)->tree)), \ typeof(*event), group_node); event; \ event = rb_entry_safe(rb_next(&event->group_node), \ typeof(*event), group_node)) /* * Add an event from the lists for its context. * Must be called with ctx->mutex and ctx->lock held. */ static void list_add_event(struct perf_event *event, struct perf_event_context *ctx) { lockdep_assert_held(&ctx->lock); WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); event->attach_state |= PERF_ATTACH_CONTEXT; event->tstamp = perf_event_time(event); /* * If we're a stand alone event or group leader, we go to the context * list, group events are kept attached to the group so that * perf_group_detach can, at all times, locate all siblings. */ if (event->group_leader == event) { event->group_caps = event->event_caps; add_event_to_groups(event, ctx); } list_add_rcu(&event->event_entry, &ctx->event_list); ctx->nr_events++; if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) ctx->nr_user++; if (event->attr.inherit_stat) ctx->nr_stat++; if (event->state > PERF_EVENT_STATE_OFF) perf_cgroup_event_enable(event, ctx); ctx->generation++; event->pmu_ctx->nr_events++; } /* * Initialize event state based on the perf_event_attr::disabled. */ static inline void perf_event__state_init(struct perf_event *event) { event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : PERF_EVENT_STATE_INACTIVE; } static int __perf_event_read_size(u64 read_format, int nr_siblings) { int entry = sizeof(u64); /* value */ int size = 0; int nr = 1; if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) size += sizeof(u64); if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) size += sizeof(u64); if (read_format & PERF_FORMAT_ID) entry += sizeof(u64); if (read_format & PERF_FORMAT_LOST) entry += sizeof(u64); if (read_format & PERF_FORMAT_GROUP) { nr += nr_siblings; size += sizeof(u64); } /* * Since perf_event_validate_size() limits this to 16k and inhibits * adding more siblings, this will never overflow. */ return size + nr * entry; } static void __perf_event_header_size(struct perf_event *event, u64 sample_type) { struct perf_sample_data *data; u16 size = 0; if (sample_type & PERF_SAMPLE_IP) size += sizeof(data->ip); if (sample_type & PERF_SAMPLE_ADDR) size += sizeof(data->addr); if (sample_type & PERF_SAMPLE_PERIOD) size += sizeof(data->period); if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) size += sizeof(data->weight.full); if (sample_type & PERF_SAMPLE_READ) size += event->read_size; if (sample_type & PERF_SAMPLE_DATA_SRC) size += sizeof(data->data_src.val); if (sample_type & PERF_SAMPLE_TRANSACTION) size += sizeof(data->txn); if (sample_type & PERF_SAMPLE_PHYS_ADDR) size += sizeof(data->phys_addr); if (sample_type & PERF_SAMPLE_CGROUP) size += sizeof(data->cgroup); if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) size += sizeof(data->data_page_size); if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) size += sizeof(data->code_page_size); event->header_size = size; } /* * Called at perf_event creation and when events are attached/detached from a * group. */ static void perf_event__header_size(struct perf_event *event) { event->read_size = __perf_event_read_size(event->attr.read_format, event->group_leader->nr_siblings); __perf_event_header_size(event, event->attr.sample_type); } static void perf_event__id_header_size(struct perf_event *event) { struct perf_sample_data *data; u64 sample_type = event->attr.sample_type; u16 size = 0; if (sample_type & PERF_SAMPLE_TID) size += sizeof(data->tid_entry); if (sample_type & PERF_SAMPLE_TIME) size += sizeof(data->time); if (sample_type & PERF_SAMPLE_IDENTIFIER) size += sizeof(data->id); if (sample_type & PERF_SAMPLE_ID) size += sizeof(data->id); if (sample_type & PERF_SAMPLE_STREAM_ID) size += sizeof(data->stream_id); if (sample_type & PERF_SAMPLE_CPU) size += sizeof(data->cpu_entry); event->id_header_size = size; } /* * Check that adding an event to the group does not result in anybody * overflowing the 64k event limit imposed by the output buffer. * * Specifically, check that the read_size for the event does not exceed 16k, * read_size being the one term that grows with groups size. Since read_size * depends on per-event read_format, also (re)check the existing events. * * This leaves 48k for the constant size fields and things like callchains, * branch stacks and register sets. */ static bool perf_event_validate_size(struct perf_event *event) { struct perf_event *sibling, *group_leader = event->group_leader; if (__perf_event_read_size(event->attr.read_format, group_leader->nr_siblings + 1) > 16*1024) return false; if (__perf_event_read_size(group_leader->attr.read_format, group_leader->nr_siblings + 1) > 16*1024) return false; /* * When creating a new group leader, group_leader->ctx is initialized * after the size has been validated, but we cannot safely use * for_each_sibling_event() until group_leader->ctx is set. A new group * leader cannot have any siblings yet, so we can safely skip checking * the non-existent siblings. */ if (event == group_leader) return true; for_each_sibling_event(sibling, group_leader) { if (__perf_event_read_size(sibling->attr.read_format, group_leader->nr_siblings + 1) > 16*1024) return false; } return true; } static void perf_group_attach(struct perf_event *event) { struct perf_event *group_leader = event->group_leader, *pos; lockdep_assert_held(&event->ctx->lock); /* * We can have double attach due to group movement (move_group) in * perf_event_open(). */ if (event->attach_state & PERF_ATTACH_GROUP) return; event->attach_state |= PERF_ATTACH_GROUP; if (group_leader == event) return; WARN_ON_ONCE(group_leader->ctx != event->ctx); group_leader->group_caps &= event->event_caps; list_add_tail(&event->sibling_list, &group_leader->sibling_list); group_leader->nr_siblings++; group_leader->group_generation++; perf_event__header_size(group_leader); for_each_sibling_event(pos, group_leader) perf_event__header_size(pos); } /* * Remove an event from the lists for its context. * Must be called with ctx->mutex and ctx->lock held. */ static void list_del_event(struct perf_event *event, struct perf_event_context *ctx) { WARN_ON_ONCE(event->ctx != ctx); lockdep_assert_held(&ctx->lock); /* * We can have double detach due to exit/hot-unplug + close. */ if (!(event->attach_state & PERF_ATTACH_CONTEXT)) return; event->attach_state &= ~PERF_ATTACH_CONTEXT; ctx->nr_events--; if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) ctx->nr_user--; if (event->attr.inherit_stat) ctx->nr_stat--; list_del_rcu(&event->event_entry); if (event->group_leader == event) del_event_from_groups(event, ctx); /* * If event was in error state, then keep it * that way, otherwise bogus counts will be * returned on read(). The only way to get out * of error state is by explicit re-enabling * of the event */ if (event->state > PERF_EVENT_STATE_OFF) { perf_cgroup_event_disable(event, ctx); perf_event_set_state(event, PERF_EVENT_STATE_OFF); } ctx->generation++; event->pmu_ctx->nr_events--; } static int perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event) { if (!has_aux(aux_event)) return 0; if (!event->pmu->aux_output_match) return 0; return event->pmu->aux_output_match(aux_event); } static void put_event(struct perf_event *event); static void event_sched_out(struct perf_event *event, struct perf_event_context *ctx); static void perf_put_aux_event(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; struct perf_event *iter; /* * If event uses aux_event tear down the link */ if (event->aux_event) { iter = event->aux_event; event->aux_event = NULL; put_event(iter); return; } /* * If the event is an aux_event, tear down all links to * it from other events. */ for_each_sibling_event(iter, event->group_leader) { if (iter->aux_event != event) continue; iter->aux_event = NULL; put_event(event); /* * If it's ACTIVE, schedule it out and put it into ERROR * state so that we don't try to schedule it again. Note * that perf_event_enable() will clear the ERROR status. */ event_sched_out(iter, ctx); perf_event_set_state(event, PERF_EVENT_STATE_ERROR); } } static bool perf_need_aux_event(struct perf_event *event) { return !!event->attr.aux_output || !!event->attr.aux_sample_size; } static int perf_get_aux_event(struct perf_event *event, struct perf_event *group_leader) { /* * Our group leader must be an aux event if we want to be * an aux_output. This way, the aux event will precede its * aux_output events in the group, and therefore will always * schedule first. */ if (!group_leader) return 0; /* * aux_output and aux_sample_size are mutually exclusive. */ if (event->attr.aux_output && event->attr.aux_sample_size) return 0; if (event->attr.aux_output && !perf_aux_output_match(event, group_leader)) return 0; if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux) return 0; if (!atomic_long_inc_not_zero(&group_leader->refcount)) return 0; /* * Link aux_outputs to their aux event; this is undone in * perf_group_detach() by perf_put_aux_event(). When the * group in torn down, the aux_output events loose their * link to the aux_event and can't schedule any more. */ event->aux_event = group_leader; return 1; } static inline struct list_head *get_event_list(struct perf_event *event) { return event->attr.pinned ? &event->pmu_ctx->pinned_active : &event->pmu_ctx->flexible_active; } /* * Events that have PERF_EV_CAP_SIBLING require being part of a group and * cannot exist on their own, schedule them out and move them into the ERROR * state. Also see _perf_event_enable(), it will not be able to recover * this ERROR state. */ static inline void perf_remove_sibling_event(struct perf_event *event) { event_sched_out(event, event->ctx); perf_event_set_state(event, PERF_EVENT_STATE_ERROR); } static void perf_group_detach(struct perf_event *event) { struct perf_event *leader = event->group_leader; struct perf_event *sibling, *tmp; struct perf_event_context *ctx = event->ctx; lockdep_assert_held(&ctx->lock); /* * We can have double detach due to exit/hot-unplug + close. */ if (!(event->attach_state & PERF_ATTACH_GROUP)) return; event->attach_state &= ~PERF_ATTACH_GROUP; perf_put_aux_event(event); /* * If this is a sibling, remove it from its group. */ if (leader != event) { list_del_init(&event->sibling_list); event->group_leader->nr_siblings--; event->group_leader->group_generation++; goto out; } /* * If this was a group event with sibling events then * upgrade the siblings to singleton events by adding them * to whatever list we are on. */ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) { if (sibling->event_caps & PERF_EV_CAP_SIBLING) perf_remove_sibling_event(sibling); sibling->group_leader = sibling; list_del_init(&sibling->sibling_list); /* Inherit group flags from the previous leader */ sibling->group_caps = event->group_caps; if (sibling->attach_state & PERF_ATTACH_CONTEXT) { add_event_to_groups(sibling, event->ctx); if (sibling->state == PERF_EVENT_STATE_ACTIVE) list_add_tail(&sibling->active_list, get_event_list(sibling)); } WARN_ON_ONCE(sibling->ctx != event->ctx); } out: for_each_sibling_event(tmp, leader) perf_event__header_size(tmp); perf_event__header_size(leader); } static void sync_child_event(struct perf_event *child_event); static void perf_child_detach(struct perf_event *event) { struct perf_event *parent_event = event->parent; if (!(event->attach_state & PERF_ATTACH_CHILD)) return; event->attach_state &= ~PERF_ATTACH_CHILD; if (WARN_ON_ONCE(!parent_event)) return; lockdep_assert_held(&parent_event->child_mutex); sync_child_event(event); list_del_init(&event->child_list); } static bool is_orphaned_event(struct perf_event *event) { return event->state == PERF_EVENT_STATE_DEAD; } static inline int event_filter_match(struct perf_event *event) { return (event->cpu == -1 || event->cpu == smp_processor_id()) && perf_cgroup_match(event); } static void event_sched_out(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event_pmu_context *epc = event->pmu_ctx; struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; // XXX cpc serialization, probably per-cpu IRQ disabled WARN_ON_ONCE(event->ctx != ctx); lockdep_assert_held(&ctx->lock); if (event->state != PERF_EVENT_STATE_ACTIVE) return; /* * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but * we can schedule events _OUT_ individually through things like * __perf_remove_from_context(). */ list_del_init(&event->active_list); perf_pmu_disable(event->pmu); event->pmu->del(event, 0); event->oncpu = -1; if (event->pending_disable) { event->pending_disable = 0; perf_cgroup_event_disable(event, ctx); state = PERF_EVENT_STATE_OFF; } perf_event_set_state(event, state); if (!is_software_event(event)) cpc->active_oncpu--; if (event->attr.freq && event->attr.sample_freq) { ctx->nr_freq--; epc->nr_freq--; } if (event->attr.exclusive || !cpc->active_oncpu) cpc->exclusive = 0; perf_pmu_enable(event->pmu); } static void group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx) { struct perf_event *event; if (group_event->state != PERF_EVENT_STATE_ACTIVE) return; perf_assert_pmu_disabled(group_event->pmu_ctx->pmu); event_sched_out(group_event, ctx); /* * Schedule out siblings (if any): */ for_each_sibling_event(event, group_event) event_sched_out(event, ctx); } #define DETACH_GROUP 0x01UL #define DETACH_CHILD 0x02UL #define DETACH_DEAD 0x04UL /* * Cross CPU call to remove a performance event * * We disable the event on the hardware level first. After that we * remove it from the context list. */ static void __perf_remove_from_context(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx, void *info) { struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx; unsigned long flags = (unsigned long)info; if (ctx->is_active & EVENT_TIME) { update_context_time(ctx); update_cgrp_time_from_cpuctx(cpuctx, false); } /* * Ensure event_sched_out() switches to OFF, at the very least * this avoids raising perf_pending_task() at this time. */ if (flags & DETACH_DEAD) event->pending_disable = 1; event_sched_out(event, ctx); if (flags & DETACH_GROUP) perf_group_detach(event); if (flags & DETACH_CHILD) perf_child_detach(event); list_del_event(event, ctx); if (flags & DETACH_DEAD) event->state = PERF_EVENT_STATE_DEAD; if (!pmu_ctx->nr_events) { pmu_ctx->rotate_necessary = 0; if (ctx->task && ctx->is_active) { struct perf_cpu_pmu_context *cpc; cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); cpc->task_epc = NULL; } } if (!ctx->nr_events && ctx->is_active) { if (ctx == &cpuctx->ctx) update_cgrp_time_from_cpuctx(cpuctx, true); ctx->is_active = 0; if (ctx->task) { WARN_ON_ONCE(cpuctx->task_ctx != ctx); cpuctx->task_ctx = NULL; } } } /* * Remove the event from a task's (or a CPU's) list of events. * * If event->ctx is a cloned context, callers must make sure that * every task struct that event->ctx->task could possibly point to * remains valid. This is OK when called from perf_release since * that only calls us on the top-level context, which can't be a clone. * When called from perf_event_exit_task, it's OK because the * context has been detached from its task. */ static void perf_remove_from_context(struct perf_event *event, unsigned long flags) { struct perf_event_context *ctx = event->ctx; lockdep_assert_held(&ctx->mutex); /* * Because of perf_event_exit_task(), perf_remove_from_context() ought * to work in the face of TASK_TOMBSTONE, unlike every other * event_function_call() user. */ raw_spin_lock_irq(&ctx->lock); if (!ctx->is_active) { __perf_remove_from_context(event, this_cpu_ptr(&perf_cpu_context), ctx, (void *)flags); raw_spin_unlock_irq(&ctx->lock); return; } raw_spin_unlock_irq(&ctx->lock); event_function_call(event, __perf_remove_from_context, (void *)flags); } /* * Cross CPU call to disable a performance event */ static void __perf_event_disable(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx, void *info) { if (event->state < PERF_EVENT_STATE_INACTIVE) return; if (ctx->is_active & EVENT_TIME) { update_context_time(ctx); update_cgrp_time_from_event(event); } perf_pmu_disable(event->pmu_ctx->pmu); if (event == event->group_leader) group_sched_out(event, ctx); else event_sched_out(event, ctx); perf_event_set_state(event, PERF_EVENT_STATE_OFF); perf_cgroup_event_disable(event, ctx); perf_pmu_enable(event->pmu_ctx->pmu); } /* * Disable an event. * * If event->ctx is a cloned context, callers must make sure that * every task struct that event->ctx->task could possibly point to * remains valid. This condition is satisfied when called through * perf_event_for_each_child or perf_event_for_each because they * hold the top-level event's child_mutex, so any descendant that * goes to exit will block in perf_event_exit_event(). * * When called from perf_pending_disable it's OK because event->ctx * is the current context on this CPU and preemption is disabled, * hence we can't get into perf_event_task_sched_out for this context. */ static void _perf_event_disable(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; raw_spin_lock_irq(&ctx->lock); if (event->state <= PERF_EVENT_STATE_OFF) { raw_spin_unlock_irq(&ctx->lock); return; } raw_spin_unlock_irq(&ctx->lock); event_function_call(event, __perf_event_disable, NULL); } void perf_event_disable_local(struct perf_event *event) { event_function_local(event, __perf_event_disable, NULL); } /* * Strictly speaking kernel users cannot create groups and therefore this * interface does not need the perf_event_ctx_lock() magic. */ void perf_event_disable(struct perf_event *event) { struct perf_event_context *ctx; ctx = perf_event_ctx_lock(event); _perf_event_disable(event); perf_event_ctx_unlock(event, ctx); } EXPORT_SYMBOL_GPL(perf_event_disable); void perf_event_disable_inatomic(struct perf_event *event) { event->pending_disable = 1; irq_work_queue(&event->pending_disable_irq); } #define MAX_INTERRUPTS (~0ULL) static void perf_log_throttle(struct perf_event *event, int enable); static void perf_log_itrace_start(struct perf_event *event); static int event_sched_in(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event_pmu_context *epc = event->pmu_ctx; struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); int ret = 0; WARN_ON_ONCE(event->ctx != ctx); lockdep_assert_held(&ctx->lock); if (event->state <= PERF_EVENT_STATE_OFF) return 0; WRITE_ONCE(event->oncpu, smp_processor_id()); /* * Order event::oncpu write to happen before the ACTIVE state is * visible. This allows perf_event_{stop,read}() to observe the correct * ->oncpu if it sees ACTIVE. */ smp_wmb(); perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE); /* * Unthrottle events, since we scheduled we might have missed several * ticks already, also for a heavily scheduling task there is little * guarantee it'll get a tick in a timely manner. */ if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { perf_log_throttle(event, 1); event->hw.interrupts = 0; } perf_pmu_disable(event->pmu); perf_log_itrace_start(event); if (event->pmu->add(event, PERF_EF_START)) { perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); event->oncpu = -1; ret = -EAGAIN; goto out; } if (!is_software_event(event)) cpc->active_oncpu++; if (event->attr.freq && event->attr.sample_freq) { ctx->nr_freq++; epc->nr_freq++; } if (event->attr.exclusive) cpc->exclusive = 1; out: perf_pmu_enable(event->pmu); return ret; } static int group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx) { struct perf_event *event, *partial_group = NULL; struct pmu *pmu = group_event->pmu_ctx->pmu; if (group_event->state == PERF_EVENT_STATE_OFF) return 0; pmu->start_txn(pmu, PERF_PMU_TXN_ADD); if (event_sched_in(group_event, ctx)) goto error; /* * Schedule in siblings as one group (if any): */ for_each_sibling_event(event, group_event) { if (event_sched_in(event, ctx)) { partial_group = event; goto group_error; } } if (!pmu->commit_txn(pmu)) return 0; group_error: /* * Groups can be scheduled in as one unit only, so undo any * partial group before returning: * The events up to the failed event are scheduled out normally. */ for_each_sibling_event(event, group_event) { if (event == partial_group) break; event_sched_out(event, ctx); } event_sched_out(group_event, ctx); error: pmu->cancel_txn(pmu); return -EAGAIN; } /* * Work out whether we can put this event group on the CPU now. */ static int group_can_go_on(struct perf_event *event, int can_add_hw) { struct perf_event_pmu_context *epc = event->pmu_ctx; struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); /* * Groups consisting entirely of software events can always go on. */ if (event->group_caps & PERF_EV_CAP_SOFTWARE) return 1; /* * If an exclusive group is already on, no other hardware * events can go on. */ if (cpc->exclusive) return 0; /* * If this group is exclusive and there are already * events on the CPU, it can't go on. */ if (event->attr.exclusive && !list_empty(get_event_list(event))) return 0; /* * Otherwise, try to add it if all previous groups were able * to go on. */ return can_add_hw; } static void add_event_to_ctx(struct perf_event *event, struct perf_event_context *ctx) { list_add_event(event, ctx); perf_group_attach(event); } static void task_ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); if (!cpuctx->task_ctx) return; if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) return; ctx_sched_out(ctx, event_type); } static void perf_event_sched_in(struct perf_cpu_context *cpuctx, struct perf_event_context *ctx) { ctx_sched_in(&cpuctx->ctx, EVENT_PINNED); if (ctx) ctx_sched_in(ctx, EVENT_PINNED); ctx_sched_in(&cpuctx->ctx, EVENT_FLEXIBLE); if (ctx) ctx_sched_in(ctx, EVENT_FLEXIBLE); } /* * We want to maintain the following priority of scheduling: * - CPU pinned (EVENT_CPU | EVENT_PINNED) * - task pinned (EVENT_PINNED) * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) * - task flexible (EVENT_FLEXIBLE). * * In order to avoid unscheduling and scheduling back in everything every * time an event is added, only do it for the groups of equal priority and * below. * * This can be called after a batch operation on task events, in which case * event_type is a bit mask of the types of events involved. For CPU events, * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. */ /* * XXX: ctx_resched() reschedule entire perf_event_context while adding new * event to the context or enabling existing event in the context. We can * probably optimize it by rescheduling only affected pmu_ctx. */ static void ctx_resched(struct perf_cpu_context *cpuctx, struct perf_event_context *task_ctx, enum event_type_t event_type) { bool cpu_event = !!(event_type & EVENT_CPU); /* * If pinned groups are involved, flexible groups also need to be * scheduled out. */ if (event_type & EVENT_PINNED) event_type |= EVENT_FLEXIBLE; event_type &= EVENT_ALL; perf_ctx_disable(&cpuctx->ctx, false); if (task_ctx) { perf_ctx_disable(task_ctx, false); task_ctx_sched_out(task_ctx, event_type); } /* * Decide which cpu ctx groups to schedule out based on the types * of events that caused rescheduling: * - EVENT_CPU: schedule out corresponding groups; * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; * - otherwise, do nothing more. */ if (cpu_event) ctx_sched_out(&cpuctx->ctx, event_type); else if (event_type & EVENT_PINNED) ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE); perf_event_sched_in(cpuctx, task_ctx); perf_ctx_enable(&cpuctx->ctx, false); if (task_ctx) perf_ctx_enable(task_ctx, false); } void perf_pmu_resched(struct pmu *pmu) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_context *task_ctx = cpuctx->task_ctx; perf_ctx_lock(cpuctx, task_ctx); ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU); perf_ctx_unlock(cpuctx, task_ctx); } /* * Cross CPU call to install and enable a performance event * * Very similar to remote_function() + event_function() but cannot assume that * things like ctx->is_active and cpuctx->task_ctx are set. */ static int __perf_install_in_context(void *info) { struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_context *task_ctx = cpuctx->task_ctx; bool reprogram = true; int ret = 0; raw_spin_lock(&cpuctx->ctx.lock); if (ctx->task) { raw_spin_lock(&ctx->lock); task_ctx = ctx; reprogram = (ctx->task == current); /* * If the task is running, it must be running on this CPU, * otherwise we cannot reprogram things. * * If its not running, we don't care, ctx->lock will * serialize against it becoming runnable. */ if (task_curr(ctx->task) && !reprogram) { ret = -ESRCH; goto unlock; } WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); } else if (task_ctx) { raw_spin_lock(&task_ctx->lock); } #ifdef CONFIG_CGROUP_PERF if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) { /* * If the current cgroup doesn't match the event's * cgroup, we should not try to schedule it. */ struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); reprogram = cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup); } #endif if (reprogram) { ctx_sched_out(ctx, EVENT_TIME); add_event_to_ctx(event, ctx); ctx_resched(cpuctx, task_ctx, get_event_type(event)); } else { add_event_to_ctx(event, ctx); } unlock: perf_ctx_unlock(cpuctx, task_ctx); return ret; } static bool exclusive_event_installable(struct perf_event *event, struct perf_event_context *ctx); /* * Attach a performance event to a context. * * Very similar to event_function_call, see comment there. */ static void perf_install_in_context(struct perf_event_context *ctx, struct perf_event *event, int cpu) { struct task_struct *task = READ_ONCE(ctx->task); lockdep_assert_held(&ctx->mutex); WARN_ON_ONCE(!exclusive_event_installable(event, ctx)); if (event->cpu != -1) WARN_ON_ONCE(event->cpu != cpu); /* * Ensures that if we can observe event->ctx, both the event and ctx * will be 'complete'. See perf_iterate_sb_cpu(). */ smp_store_release(&event->ctx, ctx); /* * perf_event_attr::disabled events will not run and can be initialized * without IPI. Except when this is the first event for the context, in * that case we need the magic of the IPI to set ctx->is_active. * * The IOC_ENABLE that is sure to follow the creation of a disabled * event will issue the IPI and reprogram the hardware. */ if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events && !is_cgroup_event(event)) { raw_spin_lock_irq(&ctx->lock); if (ctx->task == TASK_TOMBSTONE) { raw_spin_unlock_irq(&ctx->lock); return; } add_event_to_ctx(event, ctx); raw_spin_unlock_irq(&ctx->lock); return; } if (!task) { cpu_function_call(cpu, __perf_install_in_context, event); return; } /* * Should not happen, we validate the ctx is still alive before calling. */ if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) return; /* * Installing events is tricky because we cannot rely on ctx->is_active * to be set in case this is the nr_events 0 -> 1 transition. * * Instead we use task_curr(), which tells us if the task is running. * However, since we use task_curr() outside of rq::lock, we can race * against the actual state. This means the result can be wrong. * * If we get a false positive, we retry, this is harmless. * * If we get a false negative, things are complicated. If we are after * perf_event_context_sched_in() ctx::lock will serialize us, and the * value must be correct. If we're before, it doesn't matter since * perf_event_context_sched_in() will program the counter. * * However, this hinges on the remote context switch having observed * our task->perf_event_ctxp[] store, such that it will in fact take * ctx::lock in perf_event_context_sched_in(). * * We do this by task_function_call(), if the IPI fails to hit the task * we know any future context switch of task must see the * perf_event_ctpx[] store. */ /* * This smp_mb() orders the task->perf_event_ctxp[] store with the * task_cpu() load, such that if the IPI then does not find the task * running, a future context switch of that task must observe the * store. */ smp_mb(); again: if (!task_function_call(task, __perf_install_in_context, event)) return; raw_spin_lock_irq(&ctx->lock); task = ctx->task; if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { /* * Cannot happen because we already checked above (which also * cannot happen), and we hold ctx->mutex, which serializes us * against perf_event_exit_task_context(). */ raw_spin_unlock_irq(&ctx->lock); return; } /* * If the task is not running, ctx->lock will avoid it becoming so, * thus we can safely install the event. */ if (task_curr(task)) { raw_spin_unlock_irq(&ctx->lock); goto again; } add_event_to_ctx(event, ctx); raw_spin_unlock_irq(&ctx->lock); } /* * Cross CPU call to enable a performance event */ static void __perf_event_enable(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx, void *info) { struct perf_event *leader = event->group_leader; struct perf_event_context *task_ctx; if (event->state >= PERF_EVENT_STATE_INACTIVE || event->state <= PERF_EVENT_STATE_ERROR) return; if (ctx->is_active) ctx_sched_out(ctx, EVENT_TIME); perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); perf_cgroup_event_enable(event, ctx); if (!ctx->is_active) return; if (!event_filter_match(event)) { ctx_sched_in(ctx, EVENT_TIME); return; } /* * If the event is in a group and isn't the group leader, * then don't put it on unless the group is on. */ if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { ctx_sched_in(ctx, EVENT_TIME); return; } task_ctx = cpuctx->task_ctx; if (ctx->task) WARN_ON_ONCE(task_ctx != ctx); ctx_resched(cpuctx, task_ctx, get_event_type(event)); } /* * Enable an event. * * If event->ctx is a cloned context, callers must make sure that * every task struct that event->ctx->task could possibly point to * remains valid. This condition is satisfied when called through * perf_event_for_each_child or perf_event_for_each as described * for perf_event_disable. */ static void _perf_event_enable(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; raw_spin_lock_irq(&ctx->lock); if (event->state >= PERF_EVENT_STATE_INACTIVE || event->state < PERF_EVENT_STATE_ERROR) { out: raw_spin_unlock_irq(&ctx->lock); return; } /* * If the event is in error state, clear that first. * * That way, if we see the event in error state below, we know that it * has gone back into error state, as distinct from the task having * been scheduled away before the cross-call arrived. */ if (event->state == PERF_EVENT_STATE_ERROR) { /* * Detached SIBLING events cannot leave ERROR state. */ if (event->event_caps & PERF_EV_CAP_SIBLING && event->group_leader == event) goto out; event->state = PERF_EVENT_STATE_OFF; } raw_spin_unlock_irq(&ctx->lock); event_function_call(event, __perf_event_enable, NULL); } /* * See perf_event_disable(); */ void perf_event_enable(struct perf_event *event) { struct perf_event_context *ctx; ctx = perf_event_ctx_lock(event); _perf_event_enable(event); perf_event_ctx_unlock(event, ctx); } EXPORT_SYMBOL_GPL(perf_event_enable); struct stop_event_data { struct perf_event *event; unsigned int restart; }; static int __perf_event_stop(void *info) { struct stop_event_data *sd = info; struct perf_event *event = sd->event; /* if it's already INACTIVE, do nothing */ if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) return 0; /* matches smp_wmb() in event_sched_in() */ smp_rmb(); /* * There is a window with interrupts enabled before we get here, * so we need to check again lest we try to stop another CPU's event. */ if (READ_ONCE(event->oncpu) != smp_processor_id()) return -EAGAIN; event->pmu->stop(event, PERF_EF_UPDATE); /* * May race with the actual stop (through perf_pmu_output_stop()), * but it is only used for events with AUX ring buffer, and such * events will refuse to restart because of rb::aux_mmap_count==0, * see comments in perf_aux_output_begin(). * * Since this is happening on an event-local CPU, no trace is lost * while restarting. */ if (sd->restart) event->pmu->start(event, 0); return 0; } static int perf_event_stop(struct perf_event *event, int restart) { struct stop_event_data sd = { .event = event, .restart = restart, }; int ret = 0; do { if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) return 0; /* matches smp_wmb() in event_sched_in() */ smp_rmb(); /* * We only want to restart ACTIVE events, so if the event goes * inactive here (event->oncpu==-1), there's nothing more to do; * fall through with ret==-ENXIO. */ ret = cpu_function_call(READ_ONCE(event->oncpu), __perf_event_stop, &sd); } while (ret == -EAGAIN); return ret; } /* * In order to contain the amount of racy and tricky in the address filter * configuration management, it is a two part process: * * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, * we update the addresses of corresponding vmas in * event::addr_filter_ranges array and bump the event::addr_filters_gen; * (p2) when an event is scheduled in (pmu::add), it calls * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() * if the generation has changed since the previous call. * * If (p1) happens while the event is active, we restart it to force (p2). * * (1) perf_addr_filters_apply(): adjusting filters' offsets based on * pre-existing mappings, called once when new filters arrive via SET_FILTER * ioctl; * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly * registered mapping, called for every new mmap(), with mm::mmap_lock down * for reading; * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process * of exec. */ void perf_event_addr_filters_sync(struct perf_event *event) { struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); if (!has_addr_filter(event)) return; raw_spin_lock(&ifh->lock); if (event->addr_filters_gen != event->hw.addr_filters_gen) { event->pmu->addr_filters_sync(event); event->hw.addr_filters_gen = event->addr_filters_gen; } raw_spin_unlock(&ifh->lock); } EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); static int _perf_event_refresh(struct perf_event *event, int refresh) { /* * not supported on inherited events */ if (event->attr.inherit || !is_sampling_event(event)) return -EINVAL; atomic_add(refresh, &event->event_limit); _perf_event_enable(event); return 0; } /* * See perf_event_disable() */ int perf_event_refresh(struct perf_event *event, int refresh) { struct perf_event_context *ctx; int ret; ctx = perf_event_ctx_lock(event); ret = _perf_event_refresh(event, refresh); perf_event_ctx_unlock(event, ctx); return ret; } EXPORT_SYMBOL_GPL(perf_event_refresh); static int perf_event_modify_breakpoint(struct perf_event *bp, struct perf_event_attr *attr) { int err; _perf_event_disable(bp); err = modify_user_hw_breakpoint_check(bp, attr, true); if (!bp->attr.disabled) _perf_event_enable(bp); return err; } /* * Copy event-type-independent attributes that may be modified. */ static void perf_event_modify_copy_attr(struct perf_event_attr *to, const struct perf_event_attr *from) { to->sig_data = from->sig_data; } static int perf_event_modify_attr(struct perf_event *event, struct perf_event_attr *attr) { int (*func)(struct perf_event *, struct perf_event_attr *); struct perf_event *child; int err; if (event->attr.type != attr->type) return -EINVAL; switch (event->attr.type) { case PERF_TYPE_BREAKPOINT: func = perf_event_modify_breakpoint; break; default: /* Place holder for future additions. */ return -EOPNOTSUPP; } WARN_ON_ONCE(event->ctx->parent_ctx); mutex_lock(&event->child_mutex); /* * Event-type-independent attributes must be copied before event-type * modification, which will validate that final attributes match the * source attributes after all relevant attributes have been copied. */ perf_event_modify_copy_attr(&event->attr, attr); err = func(event, attr); if (err) goto out; list_for_each_entry(child, &event->child_list, child_list) { perf_event_modify_copy_attr(&child->attr, attr); err = func(child, attr); if (err) goto out; } out: mutex_unlock(&event->child_mutex); return err; } static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx, enum event_type_t event_type) { struct perf_event_context *ctx = pmu_ctx->ctx; struct perf_event *event, *tmp; struct pmu *pmu = pmu_ctx->pmu; if (ctx->task && !ctx->is_active) { struct perf_cpu_pmu_context *cpc; cpc = this_cpu_ptr(pmu->cpu_pmu_context); WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); cpc->task_epc = NULL; } if (!event_type) return; perf_pmu_disable(pmu); if (event_type & EVENT_PINNED) { list_for_each_entry_safe(event, tmp, &pmu_ctx->pinned_active, active_list) group_sched_out(event, ctx); } if (event_type & EVENT_FLEXIBLE) { list_for_each_entry_safe(event, tmp, &pmu_ctx->flexible_active, active_list) group_sched_out(event, ctx); /* * Since we cleared EVENT_FLEXIBLE, also clear * rotate_necessary, is will be reset by * ctx_flexible_sched_in() when needed. */ pmu_ctx->rotate_necessary = 0; } perf_pmu_enable(pmu); } static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_pmu_context *pmu_ctx; int is_active = ctx->is_active; bool cgroup = event_type & EVENT_CGROUP; event_type &= ~EVENT_CGROUP; lockdep_assert_held(&ctx->lock); if (likely(!ctx->nr_events)) { /* * See __perf_remove_from_context(). */ WARN_ON_ONCE(ctx->is_active); if (ctx->task) WARN_ON_ONCE(cpuctx->task_ctx); return; } /* * Always update time if it was set; not only when it changes. * Otherwise we can 'forget' to update time for any but the last * context we sched out. For example: * * ctx_sched_out(.event_type = EVENT_FLEXIBLE) * ctx_sched_out(.event_type = EVENT_PINNED) * * would only update time for the pinned events. */ if (is_active & EVENT_TIME) { /* update (and stop) ctx time */ update_context_time(ctx); update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx); /* * CPU-release for the below ->is_active store, * see __load_acquire() in perf_event_time_now() */ barrier(); } ctx->is_active &= ~event_type; if (!(ctx->is_active & EVENT_ALL)) ctx->is_active = 0; if (ctx->task) { WARN_ON_ONCE(cpuctx->task_ctx != ctx); if (!ctx->is_active) cpuctx->task_ctx = NULL; } is_active ^= ctx->is_active; /* changed bits */ list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { if (cgroup && !pmu_ctx->nr_cgroups) continue; __pmu_ctx_sched_out(pmu_ctx, is_active); } } /* * Test whether two contexts are equivalent, i.e. whether they have both been * cloned from the same version of the same context. * * Equivalence is measured using a generation number in the context that is * incremented on each modification to it; see unclone_ctx(), list_add_event() * and list_del_event(). */ static int context_equiv(struct perf_event_context *ctx1, struct perf_event_context *ctx2) { lockdep_assert_held(&ctx1->lock); lockdep_assert_held(&ctx2->lock); /* Pinning disables the swap optimization */ if (ctx1->pin_count || ctx2->pin_count) return 0; /* If ctx1 is the parent of ctx2 */ if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) return 1; /* If ctx2 is the parent of ctx1 */ if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) return 1; /* * If ctx1 and ctx2 have the same parent; we flatten the parent * hierarchy, see perf_event_init_context(). */ if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && ctx1->parent_gen == ctx2->parent_gen) return 1; /* Unmatched */ return 0; } static void __perf_event_sync_stat(struct perf_event *event, struct perf_event *next_event) { u64 value; if (!event->attr.inherit_stat) return; /* * Update the event value, we cannot use perf_event_read() * because we're in the middle of a context switch and have IRQs * disabled, which upsets smp_call_function_single(), however * we know the event must be on the current CPU, therefore we * don't need to use it. */ if (event->state == PERF_EVENT_STATE_ACTIVE) event->pmu->read(event); perf_event_update_time(event); /* * In order to keep per-task stats reliable we need to flip the event * values when we flip the contexts. */ value = local64_read(&next_event->count); value = local64_xchg(&event->count, value); local64_set(&next_event->count, value); swap(event->total_time_enabled, next_event->total_time_enabled); swap(event->total_time_running, next_event->total_time_running); /* * Since we swizzled the values, update the user visible data too. */ perf_event_update_userpage(event); perf_event_update_userpage(next_event); } static void perf_event_sync_stat(struct perf_event_context *ctx, struct perf_event_context *next_ctx) { struct perf_event *event, *next_event; if (!ctx->nr_stat) return; update_context_time(ctx); event = list_first_entry(&ctx->event_list, struct perf_event, event_entry); next_event = list_first_entry(&next_ctx->event_list, struct perf_event, event_entry); while (&event->event_entry != &ctx->event_list && &next_event->event_entry != &next_ctx->event_list) { __perf_event_sync_stat(event, next_event); event = list_next_entry(event, event_entry); next_event = list_next_entry(next_event, event_entry); } } #define double_list_for_each_entry(pos1, pos2, head1, head2, member) \ for (pos1 = list_first_entry(head1, typeof(*pos1), member), \ pos2 = list_first_entry(head2, typeof(*pos2), member); \ !list_entry_is_head(pos1, head1, member) && \ !list_entry_is_head(pos2, head2, member); \ pos1 = list_next_entry(pos1, member), \ pos2 = list_next_entry(pos2, member)) static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx, struct perf_event_context *next_ctx) { struct perf_event_pmu_context *prev_epc, *next_epc; if (!prev_ctx->nr_task_data) return; double_list_for_each_entry(prev_epc, next_epc, &prev_ctx->pmu_ctx_list, &next_ctx->pmu_ctx_list, pmu_ctx_entry) { if (WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu)) continue; /* * PMU specific parts of task perf context can require * additional synchronization. As an example of such * synchronization see implementation details of Intel * LBR call stack data profiling; */ if (prev_epc->pmu->swap_task_ctx) prev_epc->pmu->swap_task_ctx(prev_epc, next_epc); else swap(prev_epc->task_ctx_data, next_epc->task_ctx_data); } } static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in) { struct perf_event_pmu_context *pmu_ctx; struct perf_cpu_pmu_context *cpc; list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task) pmu_ctx->pmu->sched_task(pmu_ctx, sched_in); } } static void perf_event_context_sched_out(struct task_struct *task, struct task_struct *next) { struct perf_event_context *ctx = task->perf_event_ctxp; struct perf_event_context *next_ctx; struct perf_event_context *parent, *next_parent; int do_switch = 1; if (likely(!ctx)) return; rcu_read_lock(); next_ctx = rcu_dereference(next->perf_event_ctxp); if (!next_ctx) goto unlock; parent = rcu_dereference(ctx->parent_ctx); next_parent = rcu_dereference(next_ctx->parent_ctx); /* If neither context have a parent context; they cannot be clones. */ if (!parent && !next_parent) goto unlock; if (next_parent == ctx || next_ctx == parent || next_parent == parent) { /* * Looks like the two contexts are clones, so we might be * able to optimize the context switch. We lock both * contexts and check that they are clones under the * lock (including re-checking that neither has been * uncloned in the meantime). It doesn't matter which * order we take the locks because no other cpu could * be trying to lock both of these tasks. */ raw_spin_lock(&ctx->lock); raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); if (context_equiv(ctx, next_ctx)) { perf_ctx_disable(ctx, false); /* PMIs are disabled; ctx->nr_pending is stable. */ if (local_read(&ctx->nr_pending) || local_read(&next_ctx->nr_pending)) { /* * Must not swap out ctx when there's pending * events that rely on the ctx->task relation. */ raw_spin_unlock(&next_ctx->lock); rcu_read_unlock(); goto inside_switch; } WRITE_ONCE(ctx->task, next); WRITE_ONCE(next_ctx->task, task); perf_ctx_sched_task_cb(ctx, false); perf_event_swap_task_ctx_data(ctx, next_ctx); perf_ctx_enable(ctx, false); /* * RCU_INIT_POINTER here is safe because we've not * modified the ctx and the above modification of * ctx->task and ctx->task_ctx_data are immaterial * since those values are always verified under * ctx->lock which we're now holding. */ RCU_INIT_POINTER(task->perf_event_ctxp, next_ctx); RCU_INIT_POINTER(next->perf_event_ctxp, ctx); do_switch = 0; perf_event_sync_stat(ctx, next_ctx); } raw_spin_unlock(&next_ctx->lock); raw_spin_unlock(&ctx->lock); } unlock: rcu_read_unlock(); if (do_switch) { raw_spin_lock(&ctx->lock); perf_ctx_disable(ctx, false); inside_switch: perf_ctx_sched_task_cb(ctx, false); task_ctx_sched_out(ctx, EVENT_ALL); perf_ctx_enable(ctx, false); raw_spin_unlock(&ctx->lock); } } static DEFINE_PER_CPU(struct list_head, sched_cb_list); static DEFINE_PER_CPU(int, perf_sched_cb_usages); void perf_sched_cb_dec(struct pmu *pmu) { struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context); this_cpu_dec(perf_sched_cb_usages); barrier(); if (!--cpc->sched_cb_usage) list_del(&cpc->sched_cb_entry); } void perf_sched_cb_inc(struct pmu *pmu) { struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context); if (!cpc->sched_cb_usage++) list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); barrier(); this_cpu_inc(perf_sched_cb_usages); } /* * This function provides the context switch callback to the lower code * layer. It is invoked ONLY when the context switch callback is enabled. * * This callback is relevant even to per-cpu events; for example multi event * PEBS requires this to provide PID/TID information. This requires we flush * all queued PEBS records before we context switch to a new task. */ static void __perf_pmu_sched_task(struct perf_cpu_pmu_context *cpc, bool sched_in) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct pmu *pmu; pmu = cpc->epc.pmu; /* software PMUs will not have sched_task */ if (WARN_ON_ONCE(!pmu->sched_task)) return; perf_ctx_lock(cpuctx, cpuctx->task_ctx); perf_pmu_disable(pmu); pmu->sched_task(cpc->task_epc, sched_in); perf_pmu_enable(pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); } static void perf_pmu_sched_task(struct task_struct *prev, struct task_struct *next, bool sched_in) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_cpu_pmu_context *cpc; /* cpuctx->task_ctx will be handled in perf_event_context_sched_in/out */ if (prev == next || cpuctx->task_ctx) return; list_for_each_entry(cpc, this_cpu_ptr(&sched_cb_list), sched_cb_entry) __perf_pmu_sched_task(cpc, sched_in); } static void perf_event_switch(struct task_struct *task, struct task_struct *next_prev, bool sched_in); /* * Called from scheduler to remove the events of the current task, * with interrupts disabled. * * We stop each event and update the event value in event->count. * * This does not protect us against NMI, but disable() * sets the disabled bit in the control field of event _before_ * accessing the event control register. If a NMI hits, then it will * not restart the event. */ void __perf_event_task_sched_out(struct task_struct *task, struct task_struct *next) { if (__this_cpu_read(perf_sched_cb_usages)) perf_pmu_sched_task(task, next, false); if (atomic_read(&nr_switch_events)) perf_event_switch(task, next, false); perf_event_context_sched_out(task, next); /* * if cgroup events exist on this CPU, then we need * to check if we have to switch out PMU state. * cgroup event are system-wide mode only */ perf_cgroup_switch(next); } static bool perf_less_group_idx(const void *l, const void *r, void __always_unused *args) { const struct perf_event *le = *(const struct perf_event **)l; const struct perf_event *re = *(const struct perf_event **)r; return le->group_index < re->group_index; } static void swap_ptr(void *l, void *r, void __always_unused *args) { void **lp = l, **rp = r; swap(*lp, *rp); } DEFINE_MIN_HEAP(struct perf_event *, perf_event_min_heap); static const struct min_heap_callbacks perf_min_heap = { .less = perf_less_group_idx, .swp = swap_ptr, }; static void __heap_add(struct perf_event_min_heap *heap, struct perf_event *event) { struct perf_event **itrs = heap->data; if (event) { itrs[heap->nr] = event; heap->nr++; } } static void __link_epc(struct perf_event_pmu_context *pmu_ctx) { struct perf_cpu_pmu_context *cpc; if (!pmu_ctx->ctx->task) return; cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); cpc->task_epc = pmu_ctx; } static noinline int visit_groups_merge(struct perf_event_context *ctx, struct perf_event_groups *groups, int cpu, struct pmu *pmu, int (*func)(struct perf_event *, void *), void *data) { #ifdef CONFIG_CGROUP_PERF struct cgroup_subsys_state *css = NULL; #endif struct perf_cpu_context *cpuctx = NULL; /* Space for per CPU and/or any CPU event iterators. */ struct perf_event *itrs[2]; struct perf_event_min_heap event_heap; struct perf_event **evt; int ret; if (pmu->filter && pmu->filter(pmu, cpu)) return 0; if (!ctx->task) { cpuctx = this_cpu_ptr(&perf_cpu_context); event_heap = (struct perf_event_min_heap){ .data = cpuctx->heap, .nr = 0, .size = cpuctx->heap_size, }; lockdep_assert_held(&cpuctx->ctx.lock); #ifdef CONFIG_CGROUP_PERF if (cpuctx->cgrp) css = &cpuctx->cgrp->css; #endif } else { event_heap = (struct perf_event_min_heap){ .data = itrs, .nr = 0, .size = ARRAY_SIZE(itrs), }; /* Events not within a CPU context may be on any CPU. */ __heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL)); } evt = event_heap.data; __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL)); #ifdef CONFIG_CGROUP_PERF for (; css; css = css->parent) __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup)); #endif if (event_heap.nr) { __link_epc((*evt)->pmu_ctx); perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu); } min_heapify_all(&event_heap, &perf_min_heap, NULL); while (event_heap.nr) { ret = func(*evt, data); if (ret) return ret; *evt = perf_event_groups_next(*evt, pmu); if (*evt) min_heap_sift_down(&event_heap, 0, &perf_min_heap, NULL); else min_heap_pop(&event_heap, &perf_min_heap, NULL); } return 0; } /* * Because the userpage is strictly per-event (there is no concept of context, * so there cannot be a context indirection), every userpage must be updated * when context time starts :-( * * IOW, we must not miss EVENT_TIME edges. */ static inline bool event_update_userpage(struct perf_event *event) { if (likely(!atomic_read(&event->mmap_count))) return false; perf_event_update_time(event); perf_event_update_userpage(event); return true; } static inline void group_update_userpage(struct perf_event *group_event) { struct perf_event *event; if (!event_update_userpage(group_event)) return; for_each_sibling_event(event, group_event) event_update_userpage(event); } static int merge_sched_in(struct perf_event *event, void *data) { struct perf_event_context *ctx = event->ctx; int *can_add_hw = data; if (event->state <= PERF_EVENT_STATE_OFF) return 0; if (!event_filter_match(event)) return 0; if (group_can_go_on(event, *can_add_hw)) { if (!group_sched_in(event, ctx)) list_add_tail(&event->active_list, get_event_list(event)); } if (event->state == PERF_EVENT_STATE_INACTIVE) { *can_add_hw = 0; if (event->attr.pinned) { perf_cgroup_event_disable(event, ctx); perf_event_set_state(event, PERF_EVENT_STATE_ERROR); } else { struct perf_cpu_pmu_context *cpc; event->pmu_ctx->rotate_necessary = 1; cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context); perf_mux_hrtimer_restart(cpc); group_update_userpage(event); } } return 0; } static void pmu_groups_sched_in(struct perf_event_context *ctx, struct perf_event_groups *groups, struct pmu *pmu) { int can_add_hw = 1; visit_groups_merge(ctx, groups, smp_processor_id(), pmu, merge_sched_in, &can_add_hw); } static void ctx_groups_sched_in(struct perf_event_context *ctx, struct perf_event_groups *groups, bool cgroup) { struct perf_event_pmu_context *pmu_ctx; list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { if (cgroup && !pmu_ctx->nr_cgroups) continue; pmu_groups_sched_in(ctx, groups, pmu_ctx->pmu); } } static void __pmu_ctx_sched_in(struct perf_event_context *ctx, struct pmu *pmu) { pmu_groups_sched_in(ctx, &ctx->flexible_groups, pmu); } static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); int is_active = ctx->is_active; bool cgroup = event_type & EVENT_CGROUP; event_type &= ~EVENT_CGROUP; lockdep_assert_held(&ctx->lock); if (likely(!ctx->nr_events)) return; if (!(is_active & EVENT_TIME)) { /* start ctx time */ __update_context_time(ctx, false); perf_cgroup_set_timestamp(cpuctx); /* * CPU-release for the below ->is_active store, * see __load_acquire() in perf_event_time_now() */ barrier(); } ctx->is_active |= (event_type | EVENT_TIME); if (ctx->task) { if (!is_active) cpuctx->task_ctx = ctx; else WARN_ON_ONCE(cpuctx->task_ctx != ctx); } is_active ^= ctx->is_active; /* changed bits */ /* * First go through the list and put on any pinned groups * in order to give them the best chance of going on. */ if (is_active & EVENT_PINNED) ctx_groups_sched_in(ctx, &ctx->pinned_groups, cgroup); /* Then walk through the lower prio flexible groups */ if (is_active & EVENT_FLEXIBLE) ctx_groups_sched_in(ctx, &ctx->flexible_groups, cgroup); } static void perf_event_context_sched_in(struct task_struct *task) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_context *ctx; rcu_read_lock(); ctx = rcu_dereference(task->perf_event_ctxp); if (!ctx) goto rcu_unlock; if (cpuctx->task_ctx == ctx) { perf_ctx_lock(cpuctx, ctx); perf_ctx_disable(ctx, false); perf_ctx_sched_task_cb(ctx, true); perf_ctx_enable(ctx, false); perf_ctx_unlock(cpuctx, ctx); goto rcu_unlock; } perf_ctx_lock(cpuctx, ctx); /* * We must check ctx->nr_events while holding ctx->lock, such * that we serialize against perf_install_in_context(). */ if (!ctx->nr_events) goto unlock; perf_ctx_disable(ctx, false); /* * We want to keep the following priority order: * cpu pinned (that don't need to move), task pinned, * cpu flexible, task flexible. * * However, if task's ctx is not carrying any pinned * events, no need to flip the cpuctx's events around. */ if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) { perf_ctx_disable(&cpuctx->ctx, false); ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE); } perf_event_sched_in(cpuctx, ctx); perf_ctx_sched_task_cb(cpuctx->task_ctx, true); if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) perf_ctx_enable(&cpuctx->ctx, false); perf_ctx_enable(ctx, false); unlock: perf_ctx_unlock(cpuctx, ctx); rcu_unlock: rcu_read_unlock(); } /* * Called from scheduler to add the events of the current task * with interrupts disabled. * * We restore the event value and then enable it. * * This does not protect us against NMI, but enable() * sets the enabled bit in the control field of event _before_ * accessing the event control register. If a NMI hits, then it will * keep the event running. */ void __perf_event_task_sched_in(struct task_struct *prev, struct task_struct *task) { perf_event_context_sched_in(task); if (atomic_read(&nr_switch_events)) perf_event_switch(task, prev, true); if (__this_cpu_read(perf_sched_cb_usages)) perf_pmu_sched_task(prev, task, true); } static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) { u64 frequency = event->attr.sample_freq; u64 sec = NSEC_PER_SEC; u64 divisor, dividend; int count_fls, nsec_fls, frequency_fls, sec_fls; count_fls = fls64(count); nsec_fls = fls64(nsec); frequency_fls = fls64(frequency); sec_fls = 30; /* * We got @count in @nsec, with a target of sample_freq HZ * the target period becomes: * * @count * 10^9 * period = ------------------- * @nsec * sample_freq * */ /* * Reduce accuracy by one bit such that @a and @b converge * to a similar magnitude. */ #define REDUCE_FLS(a, b) \ do { \ if (a##_fls > b##_fls) { \ a >>= 1; \ a##_fls--; \ } else { \ b >>= 1; \ b##_fls--; \ } \ } while (0) /* * Reduce accuracy until either term fits in a u64, then proceed with * the other, so that finally we can do a u64/u64 division. */ while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { REDUCE_FLS(nsec, frequency); REDUCE_FLS(sec, count); } if (count_fls + sec_fls > 64) { divisor = nsec * frequency; while (count_fls + sec_fls > 64) { REDUCE_FLS(count, sec); divisor >>= 1; } dividend = count * sec; } else { dividend = count * sec; while (nsec_fls + frequency_fls > 64) { REDUCE_FLS(nsec, frequency); dividend >>= 1; } divisor = nsec * frequency; } if (!divisor) return dividend; return div64_u64(dividend, divisor); } static DEFINE_PER_CPU(int, perf_throttled_count); static DEFINE_PER_CPU(u64, perf_throttled_seq); static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) { struct hw_perf_event *hwc = &event->hw; s64 period, sample_period; s64 delta; period = perf_calculate_period(event, nsec, count); delta = (s64)(period - hwc->sample_period); delta = (delta + 7) / 8; /* low pass filter */ sample_period = hwc->sample_period + delta; if (!sample_period) sample_period = 1; hwc->sample_period = sample_period; if (local64_read(&hwc->period_left) > 8*sample_period) { if (disable) event->pmu->stop(event, PERF_EF_UPDATE); local64_set(&hwc->period_left, 0); if (disable) event->pmu->start(event, PERF_EF_RELOAD); } } static void perf_adjust_freq_unthr_events(struct list_head *event_list) { struct perf_event *event; struct hw_perf_event *hwc; u64 now, period = TICK_NSEC; s64 delta; list_for_each_entry(event, event_list, active_list) { if (event->state != PERF_EVENT_STATE_ACTIVE) continue; // XXX use visit thingy to avoid the -1,cpu match if (!event_filter_match(event)) continue; hwc = &event->hw; if (hwc->interrupts == MAX_INTERRUPTS) { hwc->interrupts = 0; perf_log_throttle(event, 1); if (!event->attr.freq || !event->attr.sample_freq) event->pmu->start(event, 0); } if (!event->attr.freq || !event->attr.sample_freq) continue; /* * stop the event and update event->count */ event->pmu->stop(event, PERF_EF_UPDATE); now = local64_read(&event->count); delta = now - hwc->freq_count_stamp; hwc->freq_count_stamp = now; /* * restart the event * reload only if value has changed * we have stopped the event so tell that * to perf_adjust_period() to avoid stopping it * twice. */ if (delta > 0) perf_adjust_period(event, period, delta, false); event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); } } /* * combine freq adjustment with unthrottling to avoid two passes over the * events. At the same time, make sure, having freq events does not change * the rate of unthrottling as that would introduce bias. */ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, bool unthrottle) { struct perf_event_pmu_context *pmu_ctx; /* * only need to iterate over all events iff: * - context have events in frequency mode (needs freq adjust) * - there are events to unthrottle on this cpu */ if (!(ctx->nr_freq || unthrottle)) return; raw_spin_lock(&ctx->lock); list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { if (!(pmu_ctx->nr_freq || unthrottle)) continue; if (!perf_pmu_ctx_is_active(pmu_ctx)) continue; if (pmu_ctx->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) continue; perf_pmu_disable(pmu_ctx->pmu); perf_adjust_freq_unthr_events(&pmu_ctx->pinned_active); perf_adjust_freq_unthr_events(&pmu_ctx->flexible_active); perf_pmu_enable(pmu_ctx->pmu); } raw_spin_unlock(&ctx->lock); } /* * Move @event to the tail of the @ctx's elegible events. */ static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) { /* * Rotate the first entry last of non-pinned groups. Rotation might be * disabled by the inheritance code. */ if (ctx->rotate_disable) return; perf_event_groups_delete(&ctx->flexible_groups, event); perf_event_groups_insert(&ctx->flexible_groups, event); } /* pick an event from the flexible_groups to rotate */ static inline struct perf_event * ctx_event_to_rotate(struct perf_event_pmu_context *pmu_ctx) { struct perf_event *event; struct rb_node *node; struct rb_root *tree; struct __group_key key = { .pmu = pmu_ctx->pmu, }; /* pick the first active flexible event */ event = list_first_entry_or_null(&pmu_ctx->flexible_active, struct perf_event, active_list); if (event) goto out; /* if no active flexible event, pick the first event */ tree = &pmu_ctx->ctx->flexible_groups.tree; if (!pmu_ctx->ctx->task) { key.cpu = smp_processor_id(); node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup); if (node) event = __node_2_pe(node); goto out; } key.cpu = -1; node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup); if (node) { event = __node_2_pe(node); goto out; } key.cpu = smp_processor_id(); node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup); if (node) event = __node_2_pe(node); out: /* * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in() * finds there are unschedulable events, it will set it again. */ pmu_ctx->rotate_necessary = 0; return event; } static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_pmu_context *cpu_epc, *task_epc = NULL; struct perf_event *cpu_event = NULL, *task_event = NULL; int cpu_rotate, task_rotate; struct pmu *pmu; /* * Since we run this from IRQ context, nobody can install new * events, thus the event count values are stable. */ cpu_epc = &cpc->epc; pmu = cpu_epc->pmu; task_epc = cpc->task_epc; cpu_rotate = cpu_epc->rotate_necessary; task_rotate = task_epc ? task_epc->rotate_necessary : 0; if (!(cpu_rotate || task_rotate)) return false; perf_ctx_lock(cpuctx, cpuctx->task_ctx); perf_pmu_disable(pmu); if (task_rotate) task_event = ctx_event_to_rotate(task_epc); if (cpu_rotate) cpu_event = ctx_event_to_rotate(cpu_epc); /* * As per the order given at ctx_resched() first 'pop' task flexible * and then, if needed CPU flexible. */ if (task_event || (task_epc && cpu_event)) { update_context_time(task_epc->ctx); __pmu_ctx_sched_out(task_epc, EVENT_FLEXIBLE); } if (cpu_event) { update_context_time(&cpuctx->ctx); __pmu_ctx_sched_out(cpu_epc, EVENT_FLEXIBLE); rotate_ctx(&cpuctx->ctx, cpu_event); __pmu_ctx_sched_in(&cpuctx->ctx, pmu); } if (task_event) rotate_ctx(task_epc->ctx, task_event); if (task_event || (task_epc && cpu_event)) __pmu_ctx_sched_in(task_epc->ctx, pmu); perf_pmu_enable(pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); return true; } void perf_event_task_tick(void) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_context *ctx; int throttled; lockdep_assert_irqs_disabled(); __this_cpu_inc(perf_throttled_seq); throttled = __this_cpu_xchg(perf_throttled_count, 0); tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); perf_adjust_freq_unthr_context(&cpuctx->ctx, !!throttled); rcu_read_lock(); ctx = rcu_dereference(current->perf_event_ctxp); if (ctx) perf_adjust_freq_unthr_context(ctx, !!throttled); rcu_read_unlock(); } static int event_enable_on_exec(struct perf_event *event, struct perf_event_context *ctx) { if (!event->attr.enable_on_exec) return 0; event->attr.enable_on_exec = 0; if (event->state >= PERF_EVENT_STATE_INACTIVE) return 0; perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); return 1; } /* * Enable all of a task's events that have been marked enable-on-exec. * This expects task == current. */ static void perf_event_enable_on_exec(struct perf_event_context *ctx) { struct perf_event_context *clone_ctx = NULL; enum event_type_t event_type = 0; struct perf_cpu_context *cpuctx; struct perf_event *event; unsigned long flags; int enabled = 0; local_irq_save(flags); if (WARN_ON_ONCE(current->perf_event_ctxp != ctx)) goto out; if (!ctx->nr_events) goto out; cpuctx = this_cpu_ptr(&perf_cpu_context); perf_ctx_lock(cpuctx, ctx); ctx_sched_out(ctx, EVENT_TIME); list_for_each_entry(event, &ctx->event_list, event_entry) { enabled |= event_enable_on_exec(event, ctx); event_type |= get_event_type(event); } /* * Unclone and reschedule this context if we enabled any event. */ if (enabled) { clone_ctx = unclone_ctx(ctx); ctx_resched(cpuctx, ctx, event_type); } else { ctx_sched_in(ctx, EVENT_TIME); } perf_ctx_unlock(cpuctx, ctx); out: local_irq_restore(flags); if (clone_ctx) put_ctx(clone_ctx); } static void perf_remove_from_owner(struct perf_event *event); static void perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx); /* * Removes all events from the current task that have been marked * remove-on-exec, and feeds their values back to parent events. */ static void perf_event_remove_on_exec(struct perf_event_context *ctx) { struct perf_event_context *clone_ctx = NULL; struct perf_event *event, *next; unsigned long flags; bool modified = false; mutex_lock(&ctx->mutex); if (WARN_ON_ONCE(ctx->task != current)) goto unlock; list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) { if (!event->attr.remove_on_exec) continue; if (!is_kernel_event(event)) perf_remove_from_owner(event); modified = true; perf_event_exit_event(event, ctx); } raw_spin_lock_irqsave(&ctx->lock, flags); if (modified) clone_ctx = unclone_ctx(ctx); raw_spin_unlock_irqrestore(&ctx->lock, flags); unlock: mutex_unlock(&ctx->mutex); if (clone_ctx) put_ctx(clone_ctx); } struct perf_read_data { struct perf_event *event; bool group; int ret; }; static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) { u16 local_pkg, event_pkg; if ((unsigned)event_cpu >= nr_cpu_ids) return event_cpu; if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { int local_cpu = smp_processor_id(); event_pkg = topology_physical_package_id(event_cpu); local_pkg = topology_physical_package_id(local_cpu); if (event_pkg == local_pkg) return local_cpu; } return event_cpu; } /* * Cross CPU call to read the hardware event */ static void __perf_event_read(void *info) { struct perf_read_data *data = info; struct perf_event *sub, *event = data->event; struct perf_event_context *ctx = event->ctx; struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct pmu *pmu = event->pmu; /* * If this is a task context, we need to check whether it is * the current task context of this cpu. If not it has been * scheduled out before the smp call arrived. In that case * event->count would have been updated to a recent sample * when the event was scheduled out. */ if (ctx->task && cpuctx->task_ctx != ctx) return; raw_spin_lock(&ctx->lock); if (ctx->is_active & EVENT_TIME) { update_context_time(ctx); update_cgrp_time_from_event(event); } perf_event_update_time(event); if (data->group) perf_event_update_sibling_time(event); if (event->state != PERF_EVENT_STATE_ACTIVE) goto unlock; if (!data->group) { pmu->read(event); data->ret = 0; goto unlock; } pmu->start_txn(pmu, PERF_PMU_TXN_READ); pmu->read(event); for_each_sibling_event(sub, event) { if (sub->state == PERF_EVENT_STATE_ACTIVE) { /* * Use sibling's PMU rather than @event's since * sibling could be on different (eg: software) PMU. */ sub->pmu->read(sub); } } data->ret = pmu->commit_txn(pmu); unlock: raw_spin_unlock(&ctx->lock); } static inline u64 perf_event_count(struct perf_event *event) { return local64_read(&event->count) + atomic64_read(&event->child_count); } static void calc_timer_values(struct perf_event *event, u64 *now, u64 *enabled, u64 *running) { u64 ctx_time; *now = perf_clock(); ctx_time = perf_event_time_now(event, *now); __perf_update_times(event, ctx_time, enabled, running); } /* * NMI-safe method to read a local event, that is an event that * is: * - either for the current task, or for this CPU * - does not have inherit set, for inherited task events * will not be local and we cannot read them atomically * - must not have a pmu::count method */ int perf_event_read_local(struct perf_event *event, u64 *value, u64 *enabled, u64 *running) { unsigned long flags; int event_oncpu; int event_cpu; int ret = 0; /* * Disabling interrupts avoids all counter scheduling (context * switches, timer based rotation and IPIs). */ local_irq_save(flags); /* * It must not be an event with inherit set, we cannot read * all child counters from atomic context. */ if (event->attr.inherit) { ret = -EOPNOTSUPP; goto out; } /* If this is a per-task event, it must be for current */ if ((event->attach_state & PERF_ATTACH_TASK) && event->hw.target != current) { ret = -EINVAL; goto out; } /* * Get the event CPU numbers, and adjust them to local if the event is * a per-package event that can be read locally */ event_oncpu = __perf_event_read_cpu(event, event->oncpu); event_cpu = __perf_event_read_cpu(event, event->cpu); /* If this is a per-CPU event, it must be for this CPU */ if (!(event->attach_state & PERF_ATTACH_TASK) && event_cpu != smp_processor_id()) { ret = -EINVAL; goto out; } /* If this is a pinned event it must be running on this CPU */ if (event->attr.pinned && event_oncpu != smp_processor_id()) { ret = -EBUSY; goto out; } /* * If the event is currently on this CPU, its either a per-task event, * or local to this CPU. Furthermore it means its ACTIVE (otherwise * oncpu == -1). */ if (event_oncpu == smp_processor_id()) event->pmu->read(event); *value = local64_read(&event->count); if (enabled || running) { u64 __enabled, __running, __now; calc_timer_values(event, &__now, &__enabled, &__running); if (enabled) *enabled = __enabled; if (running) *running = __running; } out: local_irq_restore(flags); return ret; } static int perf_event_read(struct perf_event *event, bool group) { enum perf_event_state state = READ_ONCE(event->state); int event_cpu, ret = 0; /* * If event is enabled and currently active on a CPU, update the * value in the event structure: */ again: if (state == PERF_EVENT_STATE_ACTIVE) { struct perf_read_data data; /* * Orders the ->state and ->oncpu loads such that if we see * ACTIVE we must also see the right ->oncpu. * * Matches the smp_wmb() from event_sched_in(). */ smp_rmb(); event_cpu = READ_ONCE(event->oncpu); if ((unsigned)event_cpu >= nr_cpu_ids) return 0; data = (struct perf_read_data){ .event = event, .group = group, .ret = 0, }; preempt_disable(); event_cpu = __perf_event_read_cpu(event, event_cpu); /* * Purposely ignore the smp_call_function_single() return * value. * * If event_cpu isn't a valid CPU it means the event got * scheduled out and that will have updated the event count. * * Therefore, either way, we'll have an up-to-date event count * after this. */ (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); preempt_enable(); ret = data.ret; } else if (state == PERF_EVENT_STATE_INACTIVE) { struct perf_event_context *ctx = event->ctx; unsigned long flags; raw_spin_lock_irqsave(&ctx->lock, flags); state = event->state; if (state != PERF_EVENT_STATE_INACTIVE) { raw_spin_unlock_irqrestore(&ctx->lock, flags); goto again; } /* * May read while context is not active (e.g., thread is * blocked), in that case we cannot update context time */ if (ctx->is_active & EVENT_TIME) { update_context_time(ctx); update_cgrp_time_from_event(event); } perf_event_update_time(event); if (group) perf_event_update_sibling_time(event); raw_spin_unlock_irqrestore(&ctx->lock, flags); } return ret; } /* * Initialize the perf_event context in a task_struct: */ static void __perf_event_init_context(struct perf_event_context *ctx) { raw_spin_lock_init(&ctx->lock); mutex_init(&ctx->mutex); INIT_LIST_HEAD(&ctx->pmu_ctx_list); perf_event_groups_init(&ctx->pinned_groups); perf_event_groups_init(&ctx->flexible_groups); INIT_LIST_HEAD(&ctx->event_list); refcount_set(&ctx->refcount, 1); } static void __perf_init_event_pmu_context(struct perf_event_pmu_context *epc, struct pmu *pmu) { epc->pmu = pmu; INIT_LIST_HEAD(&epc->pmu_ctx_entry); INIT_LIST_HEAD(&epc->pinned_active); INIT_LIST_HEAD(&epc->flexible_active); atomic_set(&epc->refcount, 1); } static struct perf_event_context * alloc_perf_context(struct task_struct *task) { struct perf_event_context *ctx; ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); if (!ctx) return NULL; __perf_event_init_context(ctx); if (task) ctx->task = get_task_struct(task); return ctx; } static struct task_struct * find_lively_task_by_vpid(pid_t vpid) { struct task_struct *task; rcu_read_lock(); if (!vpid) task = current; else task = find_task_by_vpid(vpid); if (task) get_task_struct(task); rcu_read_unlock(); if (!task) return ERR_PTR(-ESRCH); return task; } /* * Returns a matching context with refcount and pincount. */ static struct perf_event_context * find_get_context(struct task_struct *task, struct perf_event *event) { struct perf_event_context *ctx, *clone_ctx = NULL; struct perf_cpu_context *cpuctx; unsigned long flags; int err; if (!task) { /* Must be root to operate on a CPU event: */ err = perf_allow_cpu(&event->attr); if (err) return ERR_PTR(err); cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu); ctx = &cpuctx->ctx; get_ctx(ctx); raw_spin_lock_irqsave(&ctx->lock, flags); ++ctx->pin_count; raw_spin_unlock_irqrestore(&ctx->lock, flags); return ctx; } err = -EINVAL; retry: ctx = perf_lock_task_context(task, &flags); if (ctx) { clone_ctx = unclone_ctx(ctx); ++ctx->pin_count; raw_spin_unlock_irqrestore(&ctx->lock, flags); if (clone_ctx) put_ctx(clone_ctx); } else { ctx = alloc_perf_context(task); err = -ENOMEM; if (!ctx) goto errout; err = 0; mutex_lock(&task->perf_event_mutex); /* * If it has already passed perf_event_exit_task(). * we must see PF_EXITING, it takes this mutex too. */ if (task->flags & PF_EXITING) err = -ESRCH; else if (task->perf_event_ctxp) err = -EAGAIN; else { get_ctx(ctx); ++ctx->pin_count; rcu_assign_pointer(task->perf_event_ctxp, ctx); } mutex_unlock(&task->perf_event_mutex); if (unlikely(err)) { put_ctx(ctx); if (err == -EAGAIN) goto retry; goto errout; } } return ctx; errout: return ERR_PTR(err); } static struct perf_event_pmu_context * find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx, struct perf_event *event) { struct perf_event_pmu_context *new = NULL, *epc; void *task_ctx_data = NULL; if (!ctx->task) { /* * perf_pmu_migrate_context() / __perf_pmu_install_event() * relies on the fact that find_get_pmu_context() cannot fail * for CPU contexts. */ struct perf_cpu_pmu_context *cpc; cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu); epc = &cpc->epc; raw_spin_lock_irq(&ctx->lock); if (!epc->ctx) { atomic_set(&epc->refcount, 1); epc->embedded = 1; list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list); epc->ctx = ctx; } else { WARN_ON_ONCE(epc->ctx != ctx); atomic_inc(&epc->refcount); } raw_spin_unlock_irq(&ctx->lock); return epc; } new = kzalloc(sizeof(*epc), GFP_KERNEL); if (!new) return ERR_PTR(-ENOMEM); if (event->attach_state & PERF_ATTACH_TASK_DATA) { task_ctx_data = alloc_task_ctx_data(pmu); if (!task_ctx_data) { kfree(new); return ERR_PTR(-ENOMEM); } } __perf_init_event_pmu_context(new, pmu); /* * XXX * * lockdep_assert_held(&ctx->mutex); * * can't because perf_event_init_task() doesn't actually hold the * child_ctx->mutex. */ raw_spin_lock_irq(&ctx->lock); list_for_each_entry(epc, &ctx->pmu_ctx_list, pmu_ctx_entry) { if (epc->pmu == pmu) { WARN_ON_ONCE(epc->ctx != ctx); atomic_inc(&epc->refcount); goto found_epc; } } epc = new; new = NULL; list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list); epc->ctx = ctx; found_epc: if (task_ctx_data && !epc->task_ctx_data) { epc->task_ctx_data = task_ctx_data; task_ctx_data = NULL; ctx->nr_task_data++; } raw_spin_unlock_irq(&ctx->lock); free_task_ctx_data(pmu, task_ctx_data); kfree(new); return epc; } static void get_pmu_ctx(struct perf_event_pmu_context *epc) { WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount)); } static void free_epc_rcu(struct rcu_head *head) { struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head); kfree(epc->task_ctx_data); kfree(epc); } static void put_pmu_ctx(struct perf_event_pmu_context *epc) { struct perf_event_context *ctx = epc->ctx; unsigned long flags; /* * XXX * * lockdep_assert_held(&ctx->mutex); * * can't because of the call-site in _free_event()/put_event() * which isn't always called under ctx->mutex. */ if (!atomic_dec_and_raw_lock_irqsave(&epc->refcount, &ctx->lock, flags)) return; WARN_ON_ONCE(list_empty(&epc->pmu_ctx_entry)); list_del_init(&epc->pmu_ctx_entry); epc->ctx = NULL; WARN_ON_ONCE(!list_empty(&epc->pinned_active)); WARN_ON_ONCE(!list_empty(&epc->flexible_active)); raw_spin_unlock_irqrestore(&ctx->lock, flags); if (epc->embedded) return; call_rcu(&epc->rcu_head, free_epc_rcu); } static void perf_event_free_filter(struct perf_event *event); static void free_event_rcu(struct rcu_head *head) { struct perf_event *event = container_of(head, typeof(*event), rcu_head); if (event->ns) put_pid_ns(event->ns); perf_event_free_filter(event); kmem_cache_free(perf_event_cache, event); } static void ring_buffer_attach(struct perf_event *event, struct perf_buffer *rb); static void detach_sb_event(struct perf_event *event) { struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); raw_spin_lock(&pel->lock); list_del_rcu(&event->sb_list); raw_spin_unlock(&pel->lock); } static bool is_sb_event(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; if (event->parent) return false; if (event->attach_state & PERF_ATTACH_TASK) return false; if (attr->mmap || attr->mmap_data || attr->mmap2 || attr->comm || attr->comm_exec || attr->task || attr->ksymbol || attr->context_switch || attr->text_poke || attr->bpf_event) return true; return false; } static void unaccount_pmu_sb_event(struct perf_event *event) { if (is_sb_event(event)) detach_sb_event(event); } #ifdef CONFIG_NO_HZ_FULL static DEFINE_SPINLOCK(nr_freq_lock); #endif static void unaccount_freq_event_nohz(void) { #ifdef CONFIG_NO_HZ_FULL spin_lock(&nr_freq_lock); if (atomic_dec_and_test(&nr_freq_events)) tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); spin_unlock(&nr_freq_lock); #endif } static void unaccount_freq_event(void) { if (tick_nohz_full_enabled()) unaccount_freq_event_nohz(); else atomic_dec(&nr_freq_events); } static void unaccount_event(struct perf_event *event) { bool dec = false; if (event->parent) return; if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) dec = true; if (event->attr.mmap || event->attr.mmap_data) atomic_dec(&nr_mmap_events); if (event->attr.build_id) atomic_dec(&nr_build_id_events); if (event->attr.comm) atomic_dec(&nr_comm_events); if (event->attr.namespaces) atomic_dec(&nr_namespaces_events); if (event->attr.cgroup) atomic_dec(&nr_cgroup_events); if (event->attr.task) atomic_dec(&nr_task_events); if (event->attr.freq) unaccount_freq_event(); if (event->attr.context_switch) { dec = true; atomic_dec(&nr_switch_events); } if (is_cgroup_event(event)) dec = true; if (has_branch_stack(event)) dec = true; if (event->attr.ksymbol) atomic_dec(&nr_ksymbol_events); if (event->attr.bpf_event) atomic_dec(&nr_bpf_events); if (event->attr.text_poke) atomic_dec(&nr_text_poke_events); if (dec) { if (!atomic_add_unless(&perf_sched_count, -1, 1)) schedule_delayed_work(&perf_sched_work, HZ); } unaccount_pmu_sb_event(event); } static void perf_sched_delayed(struct work_struct *work) { mutex_lock(&perf_sched_mutex); if (atomic_dec_and_test(&perf_sched_count)) static_branch_disable(&perf_sched_events); mutex_unlock(&perf_sched_mutex); } /* * The following implement mutual exclusion of events on "exclusive" pmus * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled * at a time, so we disallow creating events that might conflict, namely: * * 1) cpu-wide events in the presence of per-task events, * 2) per-task events in the presence of cpu-wide events, * 3) two matching events on the same perf_event_context. * * The former two cases are handled in the allocation path (perf_event_alloc(), * _free_event()), the latter -- before the first perf_install_in_context(). */ static int exclusive_event_init(struct perf_event *event) { struct pmu *pmu = event->pmu; if (!is_exclusive_pmu(pmu)) return 0; /* * Prevent co-existence of per-task and cpu-wide events on the * same exclusive pmu. * * Negative pmu::exclusive_cnt means there are cpu-wide * events on this "exclusive" pmu, positive means there are * per-task events. * * Since this is called in perf_event_alloc() path, event::ctx * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK * to mean "per-task event", because unlike other attach states it * never gets cleared. */ if (event->attach_state & PERF_ATTACH_TASK) { if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) return -EBUSY; } else { if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) return -EBUSY; } return 0; } static void exclusive_event_destroy(struct perf_event *event) { struct pmu *pmu = event->pmu; if (!is_exclusive_pmu(pmu)) return; /* see comment in exclusive_event_init() */ if (event->attach_state & PERF_ATTACH_TASK) atomic_dec(&pmu->exclusive_cnt); else atomic_inc(&pmu->exclusive_cnt); } static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) { if ((e1->pmu == e2->pmu) && (e1->cpu == e2->cpu || e1->cpu == -1 || e2->cpu == -1)) return true; return false; } static bool exclusive_event_installable(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event *iter_event; struct pmu *pmu = event->pmu; lockdep_assert_held(&ctx->mutex); if (!is_exclusive_pmu(pmu)) return true; list_for_each_entry(iter_event, &ctx->event_list, event_entry) { if (exclusive_event_match(iter_event, event)) return false; } return true; } static void perf_addr_filters_splice(struct perf_event *event, struct list_head *head); static void perf_pending_task_sync(struct perf_event *event) { struct callback_head *head = &event->pending_task; if (!event->pending_work) return; /* * If the task is queued to the current task's queue, we * obviously can't wait for it to complete. Simply cancel it. */ if (task_work_cancel(current, head)) { event->pending_work = 0; local_dec(&event->ctx->nr_pending); return; } /* * All accesses related to the event are within the same RCU section in * perf_pending_task(). The RCU grace period before the event is freed * will make sure all those accesses are complete by then. */ rcuwait_wait_event(&event->pending_work_wait, !event->pending_work, TASK_UNINTERRUPTIBLE); } static void _free_event(struct perf_event *event) { irq_work_sync(&event->pending_irq); irq_work_sync(&event->pending_disable_irq); perf_pending_task_sync(event); unaccount_event(event); security_perf_event_free(event); if (event->rb) { /* * Can happen when we close an event with re-directed output. * * Since we have a 0 refcount, perf_mmap_close() will skip * over us; possibly making our ring_buffer_put() the last. */ mutex_lock(&event->mmap_mutex); ring_buffer_attach(event, NULL); mutex_unlock(&event->mmap_mutex); } if (is_cgroup_event(event)) perf_detach_cgroup(event); if (!event->parent) { if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) put_callchain_buffers(); } perf_event_free_bpf_prog(event); perf_addr_filters_splice(event, NULL); kfree(event->addr_filter_ranges); if (event->destroy) event->destroy(event); /* * Must be after ->destroy(), due to uprobe_perf_close() using * hw.target. */ if (event->hw.target) put_task_struct(event->hw.target); if (event->pmu_ctx) put_pmu_ctx(event->pmu_ctx); /* * perf_event_free_task() relies on put_ctx() being 'last', in particular * all task references must be cleaned up. */ if (event->ctx) put_ctx(event->ctx); exclusive_event_destroy(event); module_put(event->pmu->module); call_rcu(&event->rcu_head, free_event_rcu); } /* * Used to free events which have a known refcount of 1, such as in error paths * where the event isn't exposed yet and inherited events. */ static void free_event(struct perf_event *event) { if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, "unexpected event refcount: %ld; ptr=%p\n", atomic_long_read(&event->refcount), event)) { /* leak to avoid use-after-free */ return; } _free_event(event); } /* * Remove user event from the owner task. */ static void perf_remove_from_owner(struct perf_event *event) { struct task_struct *owner; rcu_read_lock(); /* * Matches the smp_store_release() in perf_event_exit_task(). If we * observe !owner it means the list deletion is complete and we can * indeed free this event, otherwise we need to serialize on * owner->perf_event_mutex. */ owner = READ_ONCE(event->owner); if (owner) { /* * Since delayed_put_task_struct() also drops the last * task reference we can safely take a new reference * while holding the rcu_read_lock(). */ get_task_struct(owner); } rcu_read_unlock(); if (owner) { /* * If we're here through perf_event_exit_task() we're already * holding ctx->mutex which would be an inversion wrt. the * normal lock order. * * However we can safely take this lock because its the child * ctx->mutex. */ mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); /* * We have to re-check the event->owner field, if it is cleared * we raced with perf_event_exit_task(), acquiring the mutex * ensured they're done, and we can proceed with freeing the * event. */ if (event->owner) { list_del_init(&event->owner_entry); smp_store_release(&event->owner, NULL); } mutex_unlock(&owner->perf_event_mutex); put_task_struct(owner); } } static void put_event(struct perf_event *event) { if (!atomic_long_dec_and_test(&event->refcount)) return; _free_event(event); } /* * Kill an event dead; while event:refcount will preserve the event * object, it will not preserve its functionality. Once the last 'user' * gives up the object, we'll destroy the thing. */ int perf_event_release_kernel(struct perf_event *event) { struct perf_event_context *ctx = event->ctx; struct perf_event *child, *tmp; LIST_HEAD(free_list); /* * If we got here through err_alloc: free_event(event); we will not * have attached to a context yet. */ if (!ctx) { WARN_ON_ONCE(event->attach_state & (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); goto no_ctx; } if (!is_kernel_event(event)) perf_remove_from_owner(event); ctx = perf_event_ctx_lock(event); WARN_ON_ONCE(ctx->parent_ctx); /* * Mark this event as STATE_DEAD, there is no external reference to it * anymore. * * Anybody acquiring event->child_mutex after the below loop _must_ * also see this, most importantly inherit_event() which will avoid * placing more children on the list. * * Thus this guarantees that we will in fact observe and kill _ALL_ * child events. */ perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD); perf_event_ctx_unlock(event, ctx); again: mutex_lock(&event->child_mutex); list_for_each_entry(child, &event->child_list, child_list) { void *var = NULL; /* * Cannot change, child events are not migrated, see the * comment with perf_event_ctx_lock_nested(). */ ctx = READ_ONCE(child->ctx); /* * Since child_mutex nests inside ctx::mutex, we must jump * through hoops. We start by grabbing a reference on the ctx. * * Since the event cannot get freed while we hold the * child_mutex, the context must also exist and have a !0 * reference count. */ get_ctx(ctx); /* * Now that we have a ctx ref, we can drop child_mutex, and * acquire ctx::mutex without fear of it going away. Then we * can re-acquire child_mutex. */ mutex_unlock(&event->child_mutex); mutex_lock(&ctx->mutex); mutex_lock(&event->child_mutex); /* * Now that we hold ctx::mutex and child_mutex, revalidate our * state, if child is still the first entry, it didn't get freed * and we can continue doing so. */ tmp = list_first_entry_or_null(&event->child_list, struct perf_event, child_list); if (tmp == child) { perf_remove_from_context(child, DETACH_GROUP); list_move(&child->child_list, &free_list); /* * This matches the refcount bump in inherit_event(); * this can't be the last reference. */ put_event(event); } else { var = &ctx->refcount; } mutex_unlock(&event->child_mutex); mutex_unlock(&ctx->mutex); put_ctx(ctx); if (var) { /* * If perf_event_free_task() has deleted all events from the * ctx while the child_mutex got released above, make sure to * notify about the preceding put_ctx(). */ smp_mb(); /* pairs with wait_var_event() */ wake_up_var(var); } goto again; } mutex_unlock(&event->child_mutex); list_for_each_entry_safe(child, tmp, &free_list, child_list) { void *var = &child->ctx->refcount; list_del(&child->child_list); free_event(child); /* * Wake any perf_event_free_task() waiting for this event to be * freed. */ smp_mb(); /* pairs with wait_var_event() */ wake_up_var(var); } no_ctx: put_event(event); /* Must be the 'last' reference */ return 0; } EXPORT_SYMBOL_GPL(perf_event_release_kernel); /* * Called when the last reference to the file is gone. */ static int perf_release(struct inode *inode, struct file *file) { perf_event_release_kernel(file->private_data); return 0; } static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) { struct perf_event *child; u64 total = 0; *enabled = 0; *running = 0; mutex_lock(&event->child_mutex); (void)perf_event_read(event, false); total += perf_event_count(event); *enabled += event->total_time_enabled + atomic64_read(&event->child_total_time_enabled); *running += event->total_time_running + atomic64_read(&event->child_total_time_running); list_for_each_entry(child, &event->child_list, child_list) { (void)perf_event_read(child, false); total += perf_event_count(child); *enabled += child->total_time_enabled; *running += child->total_time_running; } mutex_unlock(&event->child_mutex); return total; } u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) { struct perf_event_context *ctx; u64 count; ctx = perf_event_ctx_lock(event); count = __perf_event_read_value(event, enabled, running); perf_event_ctx_unlock(event, ctx); return count; } EXPORT_SYMBOL_GPL(perf_event_read_value); static int __perf_read_group_add(struct perf_event *leader, u64 read_format, u64 *values) { struct perf_event_context *ctx = leader->ctx; struct perf_event *sub, *parent; unsigned long flags; int n = 1; /* skip @nr */ int ret; ret = perf_event_read(leader, true); if (ret) return ret; raw_spin_lock_irqsave(&ctx->lock, flags); /* * Verify the grouping between the parent and child (inherited) * events is still in tact. * * Specifically: * - leader->ctx->lock pins leader->sibling_list * - parent->child_mutex pins parent->child_list * - parent->ctx->mutex pins parent->sibling_list * * Because parent->ctx != leader->ctx (and child_list nests inside * ctx->mutex), group destruction is not atomic between children, also * see perf_event_release_kernel(). Additionally, parent can grow the * group. * * Therefore it is possible to have parent and child groups in a * different configuration and summing over such a beast makes no sense * what so ever. * * Reject this. */ parent = leader->parent; if (parent && (parent->group_generation != leader->group_generation || parent->nr_siblings != leader->nr_siblings)) { ret = -ECHILD; goto unlock; } /* * Since we co-schedule groups, {enabled,running} times of siblings * will be identical to those of the leader, so we only publish one * set. */ if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { values[n++] += leader->total_time_enabled + atomic64_read(&leader->child_total_time_enabled); } if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { values[n++] += leader->total_time_running + atomic64_read(&leader->child_total_time_running); } /* * Write {count,id} tuples for every sibling. */ values[n++] += perf_event_count(leader); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); if (read_format & PERF_FORMAT_LOST) values[n++] = atomic64_read(&leader->lost_samples); for_each_sibling_event(sub, leader) { values[n++] += perf_event_count(sub); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); if (read_format & PERF_FORMAT_LOST) values[n++] = atomic64_read(&sub->lost_samples); } unlock: raw_spin_unlock_irqrestore(&ctx->lock, flags); return ret; } static int perf_read_group(struct perf_event *event, u64 read_format, char __user *buf) { struct perf_event *leader = event->group_leader, *child; struct perf_event_context *ctx = leader->ctx; int ret; u64 *values; lockdep_assert_held(&ctx->mutex); values = kzalloc(event->read_size, GFP_KERNEL); if (!values) return -ENOMEM; values[0] = 1 + leader->nr_siblings; mutex_lock(&leader->child_mutex); ret = __perf_read_group_add(leader, read_format, values); if (ret) goto unlock; list_for_each_entry(child, &leader->child_list, child_list) { ret = __perf_read_group_add(child, read_format, values); if (ret) goto unlock; } mutex_unlock(&leader->child_mutex); ret = event->read_size; if (copy_to_user(buf, values, event->read_size)) ret = -EFAULT; goto out; unlock: mutex_unlock(&leader->child_mutex); out: kfree(values); return ret; } static int perf_read_one(struct perf_event *event, u64 read_format, char __user *buf) { u64 enabled, running; u64 values[5]; int n = 0; values[n++] = __perf_event_read_value(event, &enabled, &running); if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) values[n++] = enabled; if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = running; if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(event); if (read_format & PERF_FORMAT_LOST) values[n++] = atomic64_read(&event->lost_samples); if (copy_to_user(buf, values, n * sizeof(u64))) return -EFAULT; return n * sizeof(u64); } static bool is_event_hup(struct perf_event *event) { bool no_children; if (event->state > PERF_EVENT_STATE_EXIT) return false; mutex_lock(&event->child_mutex); no_children = list_empty(&event->child_list); mutex_unlock(&event->child_mutex); return no_children; } /* * Read the performance event - simple non blocking version for now */ static ssize_t __perf_read(struct perf_event *event, char __user *buf, size_t count) { u64 read_format = event->attr.read_format; int ret; /* * Return end-of-file for a read on an event that is in * error state (i.e. because it was pinned but it couldn't be * scheduled on to the CPU at some point). */ if (event->state == PERF_EVENT_STATE_ERROR) return 0; if (count < event->read_size) return -ENOSPC; WARN_ON_ONCE(event->ctx->parent_ctx); if (read_format & PERF_FORMAT_GROUP) ret = perf_read_group(event, read_format, buf); else ret = perf_read_one(event, read_format, buf); return ret; } static ssize_t perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct perf_event *event = file->private_data; struct perf_event_context *ctx; int ret; ret = security_perf_event_read(event); if (ret) return ret; ctx = perf_event_ctx_lock(event); ret = __perf_read(event, buf, count); perf_event_ctx_unlock(event, ctx); return ret; } static __poll_t perf_poll(struct file *file, poll_table *wait) { struct perf_event *event = file->private_data; struct perf_buffer *rb; __poll_t events = EPOLLHUP; poll_wait(file, &event->waitq, wait); if (is_event_hup(event)) return events; /* * Pin the event->rb by taking event->mmap_mutex; otherwise * perf_event_set_output() can swizzle our rb and make us miss wakeups. */ mutex_lock(&event->mmap_mutex); rb = event->rb; if (rb) events = atomic_xchg(&rb->poll, 0); mutex_unlock(&event->mmap_mutex); return events; } static void _perf_event_reset(struct perf_event *event) { (void)perf_event_read(event, false); local64_set(&event->count, 0); perf_event_update_userpage(event); } /* Assume it's not an event with inherit set. */ u64 perf_event_pause(struct perf_event *event, bool reset) { struct perf_event_context *ctx; u64 count; ctx = perf_event_ctx_lock(event); WARN_ON_ONCE(event->attr.inherit); _perf_event_disable(event); count = local64_read(&event->count); if (reset) local64_set(&event->count, 0); perf_event_ctx_unlock(event, ctx); return count; } EXPORT_SYMBOL_GPL(perf_event_pause); /* * Holding the top-level event's child_mutex means that any * descendant process that has inherited this event will block * in perf_event_exit_event() if it goes to exit, thus satisfying the * task existence requirements of perf_event_enable/disable. */ static void perf_event_for_each_child(struct perf_event *event, void (*func)(struct perf_event *)) { struct perf_event *child; WARN_ON_ONCE(event->ctx->parent_ctx); mutex_lock(&event->child_mutex); func(event); list_for_each_entry(child, &event->child_list, child_list) func(child); mutex_unlock(&event->child_mutex); } static void perf_event_for_each(struct perf_event *event, void (*func)(struct perf_event *)) { struct perf_event_context *ctx = event->ctx; struct perf_event *sibling; lockdep_assert_held(&ctx->mutex); event = event->group_leader; perf_event_for_each_child(event, func); for_each_sibling_event(sibling, event) perf_event_for_each_child(sibling, func); } static void __perf_event_period(struct perf_event *event, struct perf_cpu_context *cpuctx, struct perf_event_context *ctx, void *info) { u64 value = *((u64 *)info); bool active; if (event->attr.freq) { event->attr.sample_freq = value; } else { event->attr.sample_period = value; event->hw.sample_period = value; } active = (event->state == PERF_EVENT_STATE_ACTIVE); if (active) { perf_pmu_disable(event->pmu); /* * We could be throttled; unthrottle now to avoid the tick * trying to unthrottle while we already re-started the event. */ if (event->hw.interrupts == MAX_INTERRUPTS) { event->hw.interrupts = 0; perf_log_throttle(event, 1); } event->pmu->stop(event, PERF_EF_UPDATE); } local64_set(&event->hw.period_left, 0); if (active) { event->pmu->start(event, PERF_EF_RELOAD); perf_pmu_enable(event->pmu); } } static int perf_event_check_period(struct perf_event *event, u64 value) { return event->pmu->check_period(event, value); } static int _perf_event_period(struct perf_event *event, u64 value) { if (!is_sampling_event(event)) return -EINVAL; if (!value) return -EINVAL; if (event->attr.freq && value > sysctl_perf_event_sample_rate) return -EINVAL; if (perf_event_check_period(event, value)) return -EINVAL; if (!event->attr.freq && (value & (1ULL << 63))) return -EINVAL; event_function_call(event, __perf_event_period, &value); return 0; } int perf_event_period(struct perf_event *event, u64 value) { struct perf_event_context *ctx; int ret; ctx = perf_event_ctx_lock(event); ret = _perf_event_period(event, value); perf_event_ctx_unlock(event, ctx); return ret; } EXPORT_SYMBOL_GPL(perf_event_period); static const struct file_operations perf_fops; static inline int perf_fget_light(int fd, struct fd *p) { struct fd f = fdget(fd); if (!f.file) return -EBADF; if (f.file->f_op != &perf_fops) { fdput(f); return -EBADF; } *p = f; return 0; } static int perf_event_set_output(struct perf_event *event, struct perf_event *output_event); static int perf_event_set_filter(struct perf_event *event, void __user *arg); static int perf_copy_attr(struct perf_event_attr __user *uattr, struct perf_event_attr *attr); static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) { void (*func)(struct perf_event *); u32 flags = arg; switch (cmd) { case PERF_EVENT_IOC_ENABLE: func = _perf_event_enable; break; case PERF_EVENT_IOC_DISABLE: func = _perf_event_disable; break; case PERF_EVENT_IOC_RESET: func = _perf_event_reset; break; case PERF_EVENT_IOC_REFRESH: return _perf_event_refresh(event, arg); case PERF_EVENT_IOC_PERIOD: { u64 value; if (copy_from_user(&value, (u64 __user *)arg, sizeof(value))) return -EFAULT; return _perf_event_period(event, value); } case PERF_EVENT_IOC_ID: { u64 id = primary_event_id(event); if (copy_to_user((void __user *)arg, &id, sizeof(id))) return -EFAULT; return 0; } case PERF_EVENT_IOC_SET_OUTPUT: { int ret; if (arg != -1) { struct perf_event *output_event; struct fd output; ret = perf_fget_light(arg, &output); if (ret) return ret; output_event = output.file->private_data; ret = perf_event_set_output(event, output_event); fdput(output); } else { ret = perf_event_set_output(event, NULL); } return ret; } case PERF_EVENT_IOC_SET_FILTER: return perf_event_set_filter(event, (void __user *)arg); case PERF_EVENT_IOC_SET_BPF: { struct bpf_prog *prog; int err; prog = bpf_prog_get(arg); if (IS_ERR(prog)) return PTR_ERR(prog); err = perf_event_set_bpf_prog(event, prog, 0); if (err) { bpf_prog_put(prog); return err; } return 0; } case PERF_EVENT_IOC_PAUSE_OUTPUT: { struct perf_buffer *rb; rcu_read_lock(); rb = rcu_dereference(event->rb); if (!rb || !rb->nr_pages) { rcu_read_unlock(); return -EINVAL; } rb_toggle_paused(rb, !!arg); rcu_read_unlock(); return 0; } case PERF_EVENT_IOC_QUERY_BPF: return perf_event_query_prog_array(event, (void __user *)arg); case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: { struct perf_event_attr new_attr; int err = perf_copy_attr((struct perf_event_attr __user *)arg, &new_attr); if (err) return err; return perf_event_modify_attr(event, &new_attr); } default: return -ENOTTY; } if (flags & PERF_IOC_FLAG_GROUP) perf_event_for_each(event, func); else perf_event_for_each_child(event, func); return 0; } static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct perf_event *event = file->private_data; struct perf_event_context *ctx; long ret; /* Treat ioctl like writes as it is likely a mutating operation. */ ret = security_perf_event_write(event); if (ret) return ret; ctx = perf_event_ctx_lock(event); ret = _perf_ioctl(event, cmd, arg); perf_event_ctx_unlock(event, ctx); return ret; } #ifdef CONFIG_COMPAT static long perf_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { switch (_IOC_NR(cmd)) { case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): case _IOC_NR(PERF_EVENT_IOC_ID): case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF): case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES): /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { cmd &= ~IOCSIZE_MASK; cmd |= sizeof(void *) << IOCSIZE_SHIFT; } break; } return perf_ioctl(file, cmd, arg); } #else # define perf_compat_ioctl NULL #endif int perf_event_task_enable(void) { struct perf_event_context *ctx; struct perf_event *event; mutex_lock(¤t->perf_event_mutex); list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { ctx = perf_event_ctx_lock(event); perf_event_for_each_child(event, _perf_event_enable); perf_event_ctx_unlock(event, ctx); } mutex_unlock(¤t->perf_event_mutex); return 0; } int perf_event_task_disable(void) { struct perf_event_context *ctx; struct perf_event *event; mutex_lock(¤t->perf_event_mutex); list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { ctx = perf_event_ctx_lock(event); perf_event_for_each_child(event, _perf_event_disable); perf_event_ctx_unlock(event, ctx); } mutex_unlock(¤t->perf_event_mutex); return 0; } static int perf_event_index(struct perf_event *event) { if (event->hw.state & PERF_HES_STOPPED) return 0; if (event->state != PERF_EVENT_STATE_ACTIVE) return 0; return event->pmu->event_idx(event); } static void perf_event_init_userpage(struct perf_event *event) { struct perf_event_mmap_page *userpg; struct perf_buffer *rb; rcu_read_lock(); rb = rcu_dereference(event->rb); if (!rb) goto unlock; userpg = rb->user_page; /* Allow new userspace to detect that bit 0 is deprecated */ userpg->cap_bit0_is_deprecated = 1; userpg->size = offsetof(struct perf_event_mmap_page, __reserved); userpg->data_offset = PAGE_SIZE; userpg->data_size = perf_data_size(rb); unlock: rcu_read_unlock(); } void __weak arch_perf_update_userpage( struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) { } /* * Callers need to ensure there can be no nesting of this function, otherwise * the seqlock logic goes bad. We can not serialize this because the arch * code calls this from NMI context. */ void perf_event_update_userpage(struct perf_event *event) { struct perf_event_mmap_page *userpg; struct perf_buffer *rb; u64 enabled, running, now; rcu_read_lock(); rb = rcu_dereference(event->rb); if (!rb) goto unlock; /* * compute total_time_enabled, total_time_running * based on snapshot values taken when the event * was last scheduled in. * * we cannot simply called update_context_time() * because of locking issue as we can be called in * NMI context */ calc_timer_values(event, &now, &enabled, &running); userpg = rb->user_page; /* * Disable preemption to guarantee consistent time stamps are stored to * the user page. */ preempt_disable(); ++userpg->lock; barrier(); userpg->index = perf_event_index(event); userpg->offset = perf_event_count(event); if (userpg->index) userpg->offset -= local64_read(&event->hw.prev_count); userpg->time_enabled = enabled + atomic64_read(&event->child_total_time_enabled); userpg->time_running = running + atomic64_read(&event->child_total_time_running); arch_perf_update_userpage(event, userpg, now); barrier(); ++userpg->lock; preempt_enable(); unlock: rcu_read_unlock(); } EXPORT_SYMBOL_GPL(perf_event_update_userpage); static vm_fault_t perf_mmap_fault(struct vm_fault *vmf) { struct perf_event *event = vmf->vma->vm_file->private_data; struct perf_buffer *rb; vm_fault_t ret = VM_FAULT_SIGBUS; if (vmf->flags & FAULT_FLAG_MKWRITE) { if (vmf->pgoff == 0) ret = 0; return ret; } rcu_read_lock(); rb = rcu_dereference(event->rb); if (!rb) goto unlock; if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) goto unlock; vmf->page = perf_mmap_to_page(rb, vmf->pgoff); if (!vmf->page) goto unlock; get_page(vmf->page); vmf->page->mapping = vmf->vma->vm_file->f_mapping; vmf->page->index = vmf->pgoff; ret = 0; unlock: rcu_read_unlock(); return ret; } static void ring_buffer_attach(struct perf_event *event, struct perf_buffer *rb) { struct perf_buffer *old_rb = NULL; unsigned long flags; WARN_ON_ONCE(event->parent); if (event->rb) { /* * Should be impossible, we set this when removing * event->rb_entry and wait/clear when adding event->rb_entry. */ WARN_ON_ONCE(event->rcu_pending); old_rb = event->rb; spin_lock_irqsave(&old_rb->event_lock, flags); list_del_rcu(&event->rb_entry); spin_unlock_irqrestore(&old_rb->event_lock, flags); event->rcu_batches = get_state_synchronize_rcu(); event->rcu_pending = 1; } if (rb) { if (event->rcu_pending) { cond_synchronize_rcu(event->rcu_batches); event->rcu_pending = 0; } spin_lock_irqsave(&rb->event_lock, flags); list_add_rcu(&event->rb_entry, &rb->event_list); spin_unlock_irqrestore(&rb->event_lock, flags); } /* * Avoid racing with perf_mmap_close(AUX): stop the event * before swizzling the event::rb pointer; if it's getting * unmapped, its aux_mmap_count will be 0 and it won't * restart. See the comment in __perf_pmu_output_stop(). * * Data will inevitably be lost when set_output is done in * mid-air, but then again, whoever does it like this is * not in for the data anyway. */ if (has_aux(event)) perf_event_stop(event, 0); rcu_assign_pointer(event->rb, rb); if (old_rb) { ring_buffer_put(old_rb); /* * Since we detached before setting the new rb, so that we * could attach the new rb, we could have missed a wakeup. * Provide it now. */ wake_up_all(&event->waitq); } } static void ring_buffer_wakeup(struct perf_event *event) { struct perf_buffer *rb; if (event->parent) event = event->parent; rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { list_for_each_entry_rcu(event, &rb->event_list, rb_entry) wake_up_all(&event->waitq); } rcu_read_unlock(); } struct perf_buffer *ring_buffer_get(struct perf_event *event) { struct perf_buffer *rb; if (event->parent) event = event->parent; rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { if (!refcount_inc_not_zero(&rb->refcount)) rb = NULL; } rcu_read_unlock(); return rb; } void ring_buffer_put(struct perf_buffer *rb) { if (!refcount_dec_and_test(&rb->refcount)) return; WARN_ON_ONCE(!list_empty(&rb->event_list)); call_rcu(&rb->rcu_head, rb_free_rcu); } static void perf_mmap_open(struct vm_area_struct *vma) { struct perf_event *event = vma->vm_file->private_data; atomic_inc(&event->mmap_count); atomic_inc(&event->rb->mmap_count); if (vma->vm_pgoff) atomic_inc(&event->rb->aux_mmap_count); if (event->pmu->event_mapped) event->pmu->event_mapped(event, vma->vm_mm); } static void perf_pmu_output_stop(struct perf_event *event); /* * A buffer can be mmap()ed multiple times; either directly through the same * event, or through other events by use of perf_event_set_output(). * * In order to undo the VM accounting done by perf_mmap() we need to destroy * the buffer here, where we still have a VM context. This means we need * to detach all events redirecting to us. */ static void perf_mmap_close(struct vm_area_struct *vma) { struct perf_event *event = vma->vm_file->private_data; struct perf_buffer *rb = ring_buffer_get(event); struct user_struct *mmap_user = rb->mmap_user; int mmap_locked = rb->mmap_locked; unsigned long size = perf_data_size(rb); bool detach_rest = false; if (event->pmu->event_unmapped) event->pmu->event_unmapped(event, vma->vm_mm); /* * The AUX buffer is strictly a sub-buffer, serialize using aux_mutex * to avoid complications. */ if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &rb->aux_mutex)) { /* * Stop all AUX events that are writing to this buffer, * so that we can free its AUX pages and corresponding PMU * data. Note that after rb::aux_mmap_count dropped to zero, * they won't start any more (see perf_aux_output_begin()). */ perf_pmu_output_stop(event); /* now it's safe to free the pages */ atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm); atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); /* this has to be the last one */ rb_free_aux(rb); WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); mutex_unlock(&rb->aux_mutex); } if (atomic_dec_and_test(&rb->mmap_count)) detach_rest = true; if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) goto out_put; ring_buffer_attach(event, NULL); mutex_unlock(&event->mmap_mutex); /* If there's still other mmap()s of this buffer, we're done. */ if (!detach_rest) goto out_put; /* * No other mmap()s, detach from all other events that might redirect * into the now unreachable buffer. Somewhat complicated by the * fact that rb::event_lock otherwise nests inside mmap_mutex. */ again: rcu_read_lock(); list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { if (!atomic_long_inc_not_zero(&event->refcount)) { /* * This event is en-route to free_event() which will * detach it and remove it from the list. */ continue; } rcu_read_unlock(); mutex_lock(&event->mmap_mutex); /* * Check we didn't race with perf_event_set_output() which can * swizzle the rb from under us while we were waiting to * acquire mmap_mutex. * * If we find a different rb; ignore this event, a next * iteration will no longer find it on the list. We have to * still restart the iteration to make sure we're not now * iterating the wrong list. */ if (event->rb == rb) ring_buffer_attach(event, NULL); mutex_unlock(&event->mmap_mutex); put_event(event); /* * Restart the iteration; either we're on the wrong list or * destroyed its integrity by doing a deletion. */ goto again; } rcu_read_unlock(); /* * It could be there's still a few 0-ref events on the list; they'll * get cleaned up by free_event() -- they'll also still have their * ref on the rb and will free it whenever they are done with it. * * Aside from that, this buffer is 'fully' detached and unmapped, * undo the VM accounting. */ atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked, &mmap_user->locked_vm); atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); free_uid(mmap_user); out_put: ring_buffer_put(rb); /* could be last */ } static const struct vm_operations_struct perf_mmap_vmops = { .open = perf_mmap_open, .close = perf_mmap_close, /* non mergeable */ .fault = perf_mmap_fault, .page_mkwrite = perf_mmap_fault, }; static int perf_mmap(struct file *file, struct vm_area_struct *vma) { struct perf_event *event = file->private_data; unsigned long user_locked, user_lock_limit; struct user_struct *user = current_user(); struct mutex *aux_mutex = NULL; struct perf_buffer *rb = NULL; unsigned long locked, lock_limit; unsigned long vma_size; unsigned long nr_pages; long user_extra = 0, extra = 0; int ret = 0, flags = 0; /* * Don't allow mmap() of inherited per-task counters. This would * create a performance issue due to all children writing to the * same rb. */ if (event->cpu == -1 && event->attr.inherit) return -EINVAL; if (!(vma->vm_flags & VM_SHARED)) return -EINVAL; ret = security_perf_event_read(event); if (ret) return ret; vma_size = vma->vm_end - vma->vm_start; if (vma->vm_pgoff == 0) { nr_pages = (vma_size / PAGE_SIZE) - 1; } else { /* * AUX area mapping: if rb->aux_nr_pages != 0, it's already * mapped, all subsequent mappings should have the same size * and offset. Must be above the normal perf buffer. */ u64 aux_offset, aux_size; if (!event->rb) return -EINVAL; nr_pages = vma_size / PAGE_SIZE; if (nr_pages > INT_MAX) return -ENOMEM; mutex_lock(&event->mmap_mutex); ret = -EINVAL; rb = event->rb; if (!rb) goto aux_unlock; aux_mutex = &rb->aux_mutex; mutex_lock(aux_mutex); aux_offset = READ_ONCE(rb->user_page->aux_offset); aux_size = READ_ONCE(rb->user_page->aux_size); if (aux_offset < perf_data_size(rb) + PAGE_SIZE) goto aux_unlock; if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) goto aux_unlock; /* already mapped with a different offset */ if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) goto aux_unlock; if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) goto aux_unlock; /* already mapped with a different size */ if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) goto aux_unlock; if (!is_power_of_2(nr_pages)) goto aux_unlock; if (!atomic_inc_not_zero(&rb->mmap_count)) goto aux_unlock; if (rb_has_aux(rb)) { atomic_inc(&rb->aux_mmap_count); ret = 0; goto unlock; } atomic_set(&rb->aux_mmap_count, 1); user_extra = nr_pages; goto accounting; } /* * If we have rb pages ensure they're a power-of-two number, so we * can do bitmasks instead of modulo. */ if (nr_pages != 0 && !is_power_of_2(nr_pages)) return -EINVAL; if (vma_size != PAGE_SIZE * (1 + nr_pages)) return -EINVAL; WARN_ON_ONCE(event->ctx->parent_ctx); again: mutex_lock(&event->mmap_mutex); if (event->rb) { if (data_page_nr(event->rb) != nr_pages) { ret = -EINVAL; goto unlock; } if (!atomic_inc_not_zero(&event->rb->mmap_count)) { /* * Raced against perf_mmap_close(); remove the * event and try again. */ ring_buffer_attach(event, NULL); mutex_unlock(&event->mmap_mutex); goto again; } goto unlock; } user_extra = nr_pages + 1; accounting: user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); /* * Increase the limit linearly with more CPUs: */ user_lock_limit *= num_online_cpus(); user_locked = atomic_long_read(&user->locked_vm); /* * sysctl_perf_event_mlock may have changed, so that * user->locked_vm > user_lock_limit */ if (user_locked > user_lock_limit) user_locked = user_lock_limit; user_locked += user_extra; if (user_locked > user_lock_limit) { /* * charge locked_vm until it hits user_lock_limit; * charge the rest from pinned_vm */ extra = user_locked - user_lock_limit; user_extra -= extra; } lock_limit = rlimit(RLIMIT_MEMLOCK); lock_limit >>= PAGE_SHIFT; locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; if ((locked > lock_limit) && perf_is_paranoid() && !capable(CAP_IPC_LOCK)) { ret = -EPERM; goto unlock; } WARN_ON(!rb && event->rb); if (vma->vm_flags & VM_WRITE) flags |= RING_BUFFER_WRITABLE; if (!rb) { rb = rb_alloc(nr_pages, event->attr.watermark ? event->attr.wakeup_watermark : 0, event->cpu, flags); if (!rb) { ret = -ENOMEM; goto unlock; } atomic_set(&rb->mmap_count, 1); rb->mmap_user = get_current_user(); rb->mmap_locked = extra; ring_buffer_attach(event, rb); perf_event_update_time(event); perf_event_init_userpage(event); perf_event_update_userpage(event); } else { ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, event->attr.aux_watermark, flags); if (!ret) rb->aux_mmap_locked = extra; } unlock: if (!ret) { atomic_long_add(user_extra, &user->locked_vm); atomic64_add(extra, &vma->vm_mm->pinned_vm); atomic_inc(&event->mmap_count); } else if (rb) { atomic_dec(&rb->mmap_count); } aux_unlock: if (aux_mutex) mutex_unlock(aux_mutex); mutex_unlock(&event->mmap_mutex); /* * Since pinned accounting is per vm we cannot allow fork() to copy our * vma. */ vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP); vma->vm_ops = &perf_mmap_vmops; if (event->pmu->event_mapped) event->pmu->event_mapped(event, vma->vm_mm); return ret; } static int perf_fasync(int fd, struct file *filp, int on) { struct inode *inode = file_inode(filp); struct perf_event *event = filp->private_data; int retval; inode_lock(inode); retval = fasync_helper(fd, filp, on, &event->fasync); inode_unlock(inode); if (retval < 0) return retval; return 0; } static const struct file_operations perf_fops = { .llseek = no_llseek, .release = perf_release, .read = perf_read, .poll = perf_poll, .unlocked_ioctl = perf_ioctl, .compat_ioctl = perf_compat_ioctl, .mmap = perf_mmap, .fasync = perf_fasync, }; /* * Perf event wakeup * * If there's data, ensure we set the poll() state and publish everything * to user-space before waking everybody up. */ void perf_event_wakeup(struct perf_event *event) { ring_buffer_wakeup(event); if (event->pending_kill) { kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); event->pending_kill = 0; } } static void perf_sigtrap(struct perf_event *event) { /* * We'd expect this to only occur if the irq_work is delayed and either * ctx->task or current has changed in the meantime. This can be the * case on architectures that do not implement arch_irq_work_raise(). */ if (WARN_ON_ONCE(event->ctx->task != current)) return; /* * Both perf_pending_task() and perf_pending_irq() can race with the * task exiting. */ if (current->flags & PF_EXITING) return; send_sig_perf((void __user *)event->pending_addr, event->orig_type, event->attr.sig_data); } /* * Deliver the pending work in-event-context or follow the context. */ static void __perf_pending_disable(struct perf_event *event) { int cpu = READ_ONCE(event->oncpu); /* * If the event isn't running; we done. event_sched_out() will have * taken care of things. */ if (cpu < 0) return; /* * Yay, we hit home and are in the context of the event. */ if (cpu == smp_processor_id()) { if (event->pending_disable) { event->pending_disable = 0; perf_event_disable_local(event); } return; } /* * CPU-A CPU-B * * perf_event_disable_inatomic() * @pending_disable = CPU-A; * irq_work_queue(); * * sched-out * @pending_disable = -1; * * sched-in * perf_event_disable_inatomic() * @pending_disable = CPU-B; * irq_work_queue(); // FAILS * * irq_work_run() * perf_pending_disable() * * But the event runs on CPU-B and wants disabling there. */ irq_work_queue_on(&event->pending_disable_irq, cpu); } static void perf_pending_disable(struct irq_work *entry) { struct perf_event *event = container_of(entry, struct perf_event, pending_disable_irq); int rctx; /* * If we 'fail' here, that's OK, it means recursion is already disabled * and we won't recurse 'further'. */ rctx = perf_swevent_get_recursion_context(); __perf_pending_disable(event); if (rctx >= 0) perf_swevent_put_recursion_context(rctx); } static void perf_pending_irq(struct irq_work *entry) { struct perf_event *event = container_of(entry, struct perf_event, pending_irq); int rctx; /* * If we 'fail' here, that's OK, it means recursion is already disabled * and we won't recurse 'further'. */ rctx = perf_swevent_get_recursion_context(); /* * The wakeup isn't bound to the context of the event -- it can happen * irrespective of where the event is. */ if (event->pending_wakeup) { event->pending_wakeup = 0; perf_event_wakeup(event); } if (rctx >= 0) perf_swevent_put_recursion_context(rctx); } static void perf_pending_task(struct callback_head *head) { struct perf_event *event = container_of(head, struct perf_event, pending_task); int rctx; /* * All accesses to the event must belong to the same implicit RCU read-side * critical section as the ->pending_work reset. See comment in * perf_pending_task_sync(). */ rcu_read_lock(); /* * If we 'fail' here, that's OK, it means recursion is already disabled * and we won't recurse 'further'. */ rctx = perf_swevent_get_recursion_context(); if (event->pending_work) { event->pending_work = 0; perf_sigtrap(event); local_dec(&event->ctx->nr_pending); rcuwait_wake_up(&event->pending_work_wait); } rcu_read_unlock(); if (rctx >= 0) perf_swevent_put_recursion_context(rctx); } #ifdef CONFIG_GUEST_PERF_EVENTS struct perf_guest_info_callbacks __rcu *perf_guest_cbs; DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state); DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip); DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr); void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs))) return; rcu_assign_pointer(perf_guest_cbs, cbs); static_call_update(__perf_guest_state, cbs->state); static_call_update(__perf_guest_get_ip, cbs->get_ip); /* Implementing ->handle_intel_pt_intr is optional. */ if (cbs->handle_intel_pt_intr) static_call_update(__perf_guest_handle_intel_pt_intr, cbs->handle_intel_pt_intr); } EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) { if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs)) return; rcu_assign_pointer(perf_guest_cbs, NULL); static_call_update(__perf_guest_state, (void *)&__static_call_return0); static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0); static_call_update(__perf_guest_handle_intel_pt_intr, (void *)&__static_call_return0); synchronize_rcu(); } EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); #endif static void perf_output_sample_regs(struct perf_output_handle *handle, struct pt_regs *regs, u64 mask) { int bit; DECLARE_BITMAP(_mask, 64); bitmap_from_u64(_mask, mask); for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { u64 val; val = perf_reg_value(regs, bit); perf_output_put(handle, val); } } static void perf_sample_regs_user(struct perf_regs *regs_user, struct pt_regs *regs) { if (user_mode(regs)) { regs_user->abi = perf_reg_abi(current); regs_user->regs = regs; } else if (!(current->flags & PF_KTHREAD)) { perf_get_regs_user(regs_user, regs); } else { regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; regs_user->regs = NULL; } } static void perf_sample_regs_intr(struct perf_regs *regs_intr, struct pt_regs *regs) { regs_intr->regs = regs; regs_intr->abi = perf_reg_abi(current); } /* * Get remaining task size from user stack pointer. * * It'd be better to take stack vma map and limit this more * precisely, but there's no way to get it safely under interrupt, * so using TASK_SIZE as limit. */ static u64 perf_ustack_task_size(struct pt_regs *regs) { unsigned long addr = perf_user_stack_pointer(regs); if (!addr || addr >= TASK_SIZE) return 0; return TASK_SIZE - addr; } static u16 perf_sample_ustack_size(u16 stack_size, u16 header_size, struct pt_regs *regs) { u64 task_size; /* No regs, no stack pointer, no dump. */ if (!regs) return 0; /* * Check if we fit in with the requested stack size into the: * - TASK_SIZE * If we don't, we limit the size to the TASK_SIZE. * * - remaining sample size * If we don't, we customize the stack size to * fit in to the remaining sample size. */ task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); stack_size = min(stack_size, (u16) task_size); /* Current header size plus static size and dynamic size. */ header_size += 2 * sizeof(u64); /* Do we fit in with the current stack dump size? */ if ((u16) (header_size + stack_size) < header_size) { /* * If we overflow the maximum size for the sample, * we customize the stack dump size to fit in. */ stack_size = USHRT_MAX - header_size - sizeof(u64); stack_size = round_up(stack_size, sizeof(u64)); } return stack_size; } static void perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, struct pt_regs *regs) { /* Case of a kernel thread, nothing to dump */ if (!regs) { u64 size = 0; perf_output_put(handle, size); } else { unsigned long sp; unsigned int rem; u64 dyn_size; /* * We dump: * static size * - the size requested by user or the best one we can fit * in to the sample max size * data * - user stack dump data * dynamic size * - the actual dumped size */ /* Static size. */ perf_output_put(handle, dump_size); /* Data. */ sp = perf_user_stack_pointer(regs); rem = __output_copy_user(handle, (void *) sp, dump_size); dyn_size = dump_size - rem; perf_output_skip(handle, rem); /* Dynamic size. */ perf_output_put(handle, dyn_size); } } static unsigned long perf_prepare_sample_aux(struct perf_event *event, struct perf_sample_data *data, size_t size) { struct perf_event *sampler = event->aux_event; struct perf_buffer *rb; data->aux_size = 0; if (!sampler) goto out; if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE)) goto out; if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id())) goto out; rb = ring_buffer_get(sampler); if (!rb) goto out; /* * If this is an NMI hit inside sampling code, don't take * the sample. See also perf_aux_sample_output(). */ if (READ_ONCE(rb->aux_in_sampling)) { data->aux_size = 0; } else { size = min_t(size_t, size, perf_aux_size(rb)); data->aux_size = ALIGN(size, sizeof(u64)); } ring_buffer_put(rb); out: return data->aux_size; } static long perf_pmu_snapshot_aux(struct perf_buffer *rb, struct perf_event *event, struct perf_output_handle *handle, unsigned long size) { unsigned long flags; long ret; /* * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler * paths. If we start calling them in NMI context, they may race with * the IRQ ones, that is, for example, re-starting an event that's just * been stopped, which is why we're using a separate callback that * doesn't change the event state. * * IRQs need to be disabled to prevent IPIs from racing with us. */ local_irq_save(flags); /* * Guard against NMI hits inside the critical section; * see also perf_prepare_sample_aux(). */ WRITE_ONCE(rb->aux_in_sampling, 1); barrier(); ret = event->pmu->snapshot_aux(event, handle, size); barrier(); WRITE_ONCE(rb->aux_in_sampling, 0); local_irq_restore(flags); return ret; } static void perf_aux_sample_output(struct perf_event *event, struct perf_output_handle *handle, struct perf_sample_data *data) { struct perf_event *sampler = event->aux_event; struct perf_buffer *rb; unsigned long pad; long size; if (WARN_ON_ONCE(!sampler || !data->aux_size)) return; rb = ring_buffer_get(sampler); if (!rb) return; size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size); /* * An error here means that perf_output_copy() failed (returned a * non-zero surplus that it didn't copy), which in its current * enlightened implementation is not possible. If that changes, we'd * like to know. */ if (WARN_ON_ONCE(size < 0)) goto out_put; /* * The pad comes from ALIGN()ing data->aux_size up to u64 in * perf_prepare_sample_aux(), so should not be more than that. */ pad = data->aux_size - size; if (WARN_ON_ONCE(pad >= sizeof(u64))) pad = 8; if (pad) { u64 zero = 0; perf_output_copy(handle, &zero, pad); } out_put: ring_buffer_put(rb); } /* * A set of common sample data types saved even for non-sample records * when event->attr.sample_id_all is set. */ #define PERF_SAMPLE_ID_ALL (PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \ PERF_SAMPLE_ID | PERF_SAMPLE_STREAM_ID | \ PERF_SAMPLE_CPU | PERF_SAMPLE_IDENTIFIER) static void __perf_event_header__init_id(struct perf_sample_data *data, struct perf_event *event, u64 sample_type) { data->type = event->attr.sample_type; data->sample_flags |= data->type & PERF_SAMPLE_ID_ALL; if (sample_type & PERF_SAMPLE_TID) { /* namespace issues */ data->tid_entry.pid = perf_event_pid(event, current); data->tid_entry.tid = perf_event_tid(event, current); } if (sample_type & PERF_SAMPLE_TIME) data->time = perf_event_clock(event); if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) data->id = primary_event_id(event); if (sample_type & PERF_SAMPLE_STREAM_ID) data->stream_id = event->id; if (sample_type & PERF_SAMPLE_CPU) { data->cpu_entry.cpu = raw_smp_processor_id(); data->cpu_entry.reserved = 0; } } void perf_event_header__init_id(struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event) { if (event->attr.sample_id_all) { header->size += event->id_header_size; __perf_event_header__init_id(data, event, event->attr.sample_type); } } static void __perf_event__output_id_sample(struct perf_output_handle *handle, struct perf_sample_data *data) { u64 sample_type = data->type; if (sample_type & PERF_SAMPLE_TID) perf_output_put(handle, data->tid_entry); if (sample_type & PERF_SAMPLE_TIME) perf_output_put(handle, data->time); if (sample_type & PERF_SAMPLE_ID) perf_output_put(handle, data->id); if (sample_type & PERF_SAMPLE_STREAM_ID) perf_output_put(handle, data->stream_id); if (sample_type & PERF_SAMPLE_CPU) perf_output_put(handle, data->cpu_entry); if (sample_type & PERF_SAMPLE_IDENTIFIER) perf_output_put(handle, data->id); } void perf_event__output_id_sample(struct perf_event *event, struct perf_output_handle *handle, struct perf_sample_data *sample) { if (event->attr.sample_id_all) __perf_event__output_id_sample(handle, sample); } static void perf_output_read_one(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running) { u64 read_format = event->attr.read_format; u64 values[5]; int n = 0; values[n++] = perf_event_count(event); if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { values[n++] = enabled + atomic64_read(&event->child_total_time_enabled); } if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { values[n++] = running + atomic64_read(&event->child_total_time_running); } if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(event); if (read_format & PERF_FORMAT_LOST) values[n++] = atomic64_read(&event->lost_samples); __output_copy(handle, values, n * sizeof(u64)); } static void perf_output_read_group(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running) { struct perf_event *leader = event->group_leader, *sub; u64 read_format = event->attr.read_format; unsigned long flags; u64 values[6]; int n = 0; /* * Disabling interrupts avoids all counter scheduling * (context switches, timer based rotation and IPIs). */ local_irq_save(flags); values[n++] = 1 + leader->nr_siblings; if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) values[n++] = enabled; if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) values[n++] = running; if ((leader != event) && (leader->state == PERF_EVENT_STATE_ACTIVE)) leader->pmu->read(leader); values[n++] = perf_event_count(leader); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(leader); if (read_format & PERF_FORMAT_LOST) values[n++] = atomic64_read(&leader->lost_samples); __output_copy(handle, values, n * sizeof(u64)); for_each_sibling_event(sub, leader) { n = 0; if ((sub != event) && (sub->state == PERF_EVENT_STATE_ACTIVE)) sub->pmu->read(sub); values[n++] = perf_event_count(sub); if (read_format & PERF_FORMAT_ID) values[n++] = primary_event_id(sub); if (read_format & PERF_FORMAT_LOST) values[n++] = atomic64_read(&sub->lost_samples); __output_copy(handle, values, n * sizeof(u64)); } local_irq_restore(flags); } #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ PERF_FORMAT_TOTAL_TIME_RUNNING) /* * XXX PERF_SAMPLE_READ vs inherited events seems difficult. * * The problem is that its both hard and excessively expensive to iterate the * child list, not to mention that its impossible to IPI the children running * on another CPU, from interrupt/NMI context. */ static void perf_output_read(struct perf_output_handle *handle, struct perf_event *event) { u64 enabled = 0, running = 0, now; u64 read_format = event->attr.read_format; /* * compute total_time_enabled, total_time_running * based on snapshot values taken when the event * was last scheduled in. * * we cannot simply called update_context_time() * because of locking issue as we are called in * NMI context */ if (read_format & PERF_FORMAT_TOTAL_TIMES) calc_timer_values(event, &now, &enabled, &running); if (event->attr.read_format & PERF_FORMAT_GROUP) perf_output_read_group(handle, event, enabled, running); else perf_output_read_one(handle, event, enabled, running); } void perf_output_sample(struct perf_output_handle *handle, struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event) { u64 sample_type = data->type; perf_output_put(handle, *header); if (sample_type & PERF_SAMPLE_IDENTIFIER) perf_output_put(handle, data->id); if (sample_type & PERF_SAMPLE_IP) perf_output_put(handle, data->ip); if (sample_type & PERF_SAMPLE_TID) perf_output_put(handle, data->tid_entry); if (sample_type & PERF_SAMPLE_TIME) perf_output_put(handle, data->time); if (sample_type & PERF_SAMPLE_ADDR) perf_output_put(handle, data->addr); if (sample_type & PERF_SAMPLE_ID) perf_output_put(handle, data->id); if (sample_type & PERF_SAMPLE_STREAM_ID) perf_output_put(handle, data->stream_id); if (sample_type & PERF_SAMPLE_CPU) perf_output_put(handle, data->cpu_entry); if (sample_type & PERF_SAMPLE_PERIOD) perf_output_put(handle, data->period); if (sample_type & PERF_SAMPLE_READ) perf_output_read(handle, event); if (sample_type & PERF_SAMPLE_CALLCHAIN) { int size = 1; size += data->callchain->nr; size *= sizeof(u64); __output_copy(handle, data->callchain, size); } if (sample_type & PERF_SAMPLE_RAW) { struct perf_raw_record *raw = data->raw; if (raw) { struct perf_raw_frag *frag = &raw->frag; perf_output_put(handle, raw->size); do { if (frag->copy) { __output_custom(handle, frag->copy, frag->data, frag->size); } else { __output_copy(handle, frag->data, frag->size); } if (perf_raw_frag_last(frag)) break; frag = frag->next; } while (1); if (frag->pad) __output_skip(handle, NULL, frag->pad); } else { struct { u32 size; u32 data; } raw = { .size = sizeof(u32), .data = 0, }; perf_output_put(handle, raw); } } if (sample_type & PERF_SAMPLE_BRANCH_STACK) { if (data->br_stack) { size_t size; size = data->br_stack->nr * sizeof(struct perf_branch_entry); perf_output_put(handle, data->br_stack->nr); if (branch_sample_hw_index(event)) perf_output_put(handle, data->br_stack->hw_idx); perf_output_copy(handle, data->br_stack->entries, size); /* * Add the extension space which is appended * right after the struct perf_branch_stack. */ if (data->br_stack_cntr) { size = data->br_stack->nr * sizeof(u64); perf_output_copy(handle, data->br_stack_cntr, size); } } else { /* * we always store at least the value of nr */ u64 nr = 0; perf_output_put(handle, nr); } } if (sample_type & PERF_SAMPLE_REGS_USER) { u64 abi = data->regs_user.abi; /* * If there are no regs to dump, notice it through * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). */ perf_output_put(handle, abi); if (abi) { u64 mask = event->attr.sample_regs_user; perf_output_sample_regs(handle, data->regs_user.regs, mask); } } if (sample_type & PERF_SAMPLE_STACK_USER) { perf_output_sample_ustack(handle, data->stack_user_size, data->regs_user.regs); } if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) perf_output_put(handle, data->weight.full); if (sample_type & PERF_SAMPLE_DATA_SRC) perf_output_put(handle, data->data_src.val); if (sample_type & PERF_SAMPLE_TRANSACTION) perf_output_put(handle, data->txn); if (sample_type & PERF_SAMPLE_REGS_INTR) { u64 abi = data->regs_intr.abi; /* * If there are no regs to dump, notice it through * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). */ perf_output_put(handle, abi); if (abi) { u64 mask = event->attr.sample_regs_intr; perf_output_sample_regs(handle, data->regs_intr.regs, mask); } } if (sample_type & PERF_SAMPLE_PHYS_ADDR) perf_output_put(handle, data->phys_addr); if (sample_type & PERF_SAMPLE_CGROUP) perf_output_put(handle, data->cgroup); if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) perf_output_put(handle, data->data_page_size); if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) perf_output_put(handle, data->code_page_size); if (sample_type & PERF_SAMPLE_AUX) { perf_output_put(handle, data->aux_size); if (data->aux_size) perf_aux_sample_output(event, handle, data); } if (!event->attr.watermark) { int wakeup_events = event->attr.wakeup_events; if (wakeup_events) { struct perf_buffer *rb = handle->rb; int events = local_inc_return(&rb->events); if (events >= wakeup_events) { local_sub(wakeup_events, &rb->events); local_inc(&rb->wakeup); } } } } static u64 perf_virt_to_phys(u64 virt) { u64 phys_addr = 0; if (!virt) return 0; if (virt >= TASK_SIZE) { /* If it's vmalloc()d memory, leave phys_addr as 0 */ if (virt_addr_valid((void *)(uintptr_t)virt) && !(virt >= VMALLOC_START && virt < VMALLOC_END)) phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); } else { /* * Walking the pages tables for user address. * Interrupts are disabled, so it prevents any tear down * of the page tables. * Try IRQ-safe get_user_page_fast_only first. * If failed, leave phys_addr as 0. */ if (current->mm != NULL) { struct page *p; pagefault_disable(); if (get_user_page_fast_only(virt, 0, &p)) { phys_addr = page_to_phys(p) + virt % PAGE_SIZE; put_page(p); } pagefault_enable(); } } return phys_addr; } /* * Return the pagetable size of a given virtual address. */ static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr) { u64 size = 0; #ifdef CONFIG_HAVE_GUP_FAST pgd_t *pgdp, pgd; p4d_t *p4dp, p4d; pud_t *pudp, pud; pmd_t *pmdp, pmd; pte_t *ptep, pte; pgdp = pgd_offset(mm, addr); pgd = READ_ONCE(*pgdp); if (pgd_none(pgd)) return 0; if (pgd_leaf(pgd)) return pgd_leaf_size(pgd); p4dp = p4d_offset_lockless(pgdp, pgd, addr); p4d = READ_ONCE(*p4dp); if (!p4d_present(p4d)) return 0; if (p4d_leaf(p4d)) return p4d_leaf_size(p4d); pudp = pud_offset_lockless(p4dp, p4d, addr); pud = READ_ONCE(*pudp); if (!pud_present(pud)) return 0; if (pud_leaf(pud)) return pud_leaf_size(pud); pmdp = pmd_offset_lockless(pudp, pud, addr); again: pmd = pmdp_get_lockless(pmdp); if (!pmd_present(pmd)) return 0; if (pmd_leaf(pmd)) return pmd_leaf_size(pmd); ptep = pte_offset_map(&pmd, addr); if (!ptep) goto again; pte = ptep_get_lockless(ptep); if (pte_present(pte)) size = __pte_leaf_size(pmd, pte); pte_unmap(ptep); #endif /* CONFIG_HAVE_GUP_FAST */ return size; } static u64 perf_get_page_size(unsigned long addr) { struct mm_struct *mm; unsigned long flags; u64 size; if (!addr) return 0; /* * Software page-table walkers must disable IRQs, * which prevents any tear down of the page tables. */ local_irq_save(flags); mm = current->mm; if (!mm) { /* * For kernel threads and the like, use init_mm so that * we can find kernel memory. */ mm = &init_mm; } size = perf_get_pgtable_size(mm, addr); local_irq_restore(flags); return size; } static struct perf_callchain_entry __empty_callchain = { .nr = 0, }; struct perf_callchain_entry * perf_callchain(struct perf_event *event, struct pt_regs *regs) { bool kernel = !event->attr.exclude_callchain_kernel; bool user = !event->attr.exclude_callchain_user; /* Disallow cross-task user callchains. */ bool crosstask = event->ctx->task && event->ctx->task != current; const u32 max_stack = event->attr.sample_max_stack; struct perf_callchain_entry *callchain; if (!kernel && !user) return &__empty_callchain; callchain = get_perf_callchain(regs, 0, kernel, user, max_stack, crosstask, true); return callchain ?: &__empty_callchain; } static __always_inline u64 __cond_set(u64 flags, u64 s, u64 d) { return d * !!(flags & s); } void perf_prepare_sample(struct perf_sample_data *data, struct perf_event *event, struct pt_regs *regs) { u64 sample_type = event->attr.sample_type; u64 filtered_sample_type; /* * Add the sample flags that are dependent to others. And clear the * sample flags that have already been done by the PMU driver. */ filtered_sample_type = sample_type; filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_CODE_PAGE_SIZE, PERF_SAMPLE_IP); filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_DATA_PAGE_SIZE | PERF_SAMPLE_PHYS_ADDR, PERF_SAMPLE_ADDR); filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_STACK_USER, PERF_SAMPLE_REGS_USER); filtered_sample_type &= ~data->sample_flags; if (filtered_sample_type == 0) { /* Make sure it has the correct data->type for output */ data->type = event->attr.sample_type; return; } __perf_event_header__init_id(data, event, filtered_sample_type); if (filtered_sample_type & PERF_SAMPLE_IP) { data->ip = perf_instruction_pointer(regs); data->sample_flags |= PERF_SAMPLE_IP; } if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN) perf_sample_save_callchain(data, event, regs); if (filtered_sample_type & PERF_SAMPLE_RAW) { data->raw = NULL; data->dyn_size += sizeof(u64); data->sample_flags |= PERF_SAMPLE_RAW; } if (filtered_sample_type & PERF_SAMPLE_BRANCH_STACK) { data->br_stack = NULL; data->dyn_size += sizeof(u64); data->sample_flags |= PERF_SAMPLE_BRANCH_STACK; } if (filtered_sample_type & PERF_SAMPLE_REGS_USER) perf_sample_regs_user(&data->regs_user, regs); /* * It cannot use the filtered_sample_type here as REGS_USER can be set * by STACK_USER (using __cond_set() above) and we don't want to update * the dyn_size if it's not requested by users. */ if ((sample_type & ~data->sample_flags) & PERF_SAMPLE_REGS_USER) { /* regs dump ABI info */ int size = sizeof(u64); if (data->regs_user.regs) { u64 mask = event->attr.sample_regs_user; size += hweight64(mask) * sizeof(u64); } data->dyn_size += size; data->sample_flags |= PERF_SAMPLE_REGS_USER; } if (filtered_sample_type & PERF_SAMPLE_STACK_USER) { /* * Either we need PERF_SAMPLE_STACK_USER bit to be always * processed as the last one or have additional check added * in case new sample type is added, because we could eat * up the rest of the sample size. */ u16 stack_size = event->attr.sample_stack_user; u16 header_size = perf_sample_data_size(data, event); u16 size = sizeof(u64); stack_size = perf_sample_ustack_size(stack_size, header_size, data->regs_user.regs); /* * If there is something to dump, add space for the dump * itself and for the field that tells the dynamic size, * which is how many have been actually dumped. */ if (stack_size) size += sizeof(u64) + stack_size; data->stack_user_size = stack_size; data->dyn_size += size; data->sample_flags |= PERF_SAMPLE_STACK_USER; } if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) { data->weight.full = 0; data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE; } if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) { data->data_src.val = PERF_MEM_NA; data->sample_flags |= PERF_SAMPLE_DATA_SRC; } if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) { data->txn = 0; data->sample_flags |= PERF_SAMPLE_TRANSACTION; } if (filtered_sample_type & PERF_SAMPLE_ADDR) { data->addr = 0; data->sample_flags |= PERF_SAMPLE_ADDR; } if (filtered_sample_type & PERF_SAMPLE_REGS_INTR) { /* regs dump ABI info */ int size = sizeof(u64); perf_sample_regs_intr(&data->regs_intr, regs); if (data->regs_intr.regs) { u64 mask = event->attr.sample_regs_intr; size += hweight64(mask) * sizeof(u64); } data->dyn_size += size; data->sample_flags |= PERF_SAMPLE_REGS_INTR; } if (filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) { data->phys_addr = perf_virt_to_phys(data->addr); data->sample_flags |= PERF_SAMPLE_PHYS_ADDR; } #ifdef CONFIG_CGROUP_PERF if (filtered_sample_type & PERF_SAMPLE_CGROUP) { struct cgroup *cgrp; /* protected by RCU */ cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup; data->cgroup = cgroup_id(cgrp); data->sample_flags |= PERF_SAMPLE_CGROUP; } #endif /* * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr, * but the value will not dump to the userspace. */ if (filtered_sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) { data->data_page_size = perf_get_page_size(data->addr); data->sample_flags |= PERF_SAMPLE_DATA_PAGE_SIZE; } if (filtered_sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) { data->code_page_size = perf_get_page_size(data->ip); data->sample_flags |= PERF_SAMPLE_CODE_PAGE_SIZE; } if (filtered_sample_type & PERF_SAMPLE_AUX) { u64 size; u16 header_size = perf_sample_data_size(data, event); header_size += sizeof(u64); /* size */ /* * Given the 16bit nature of header::size, an AUX sample can * easily overflow it, what with all the preceding sample bits. * Make sure this doesn't happen by using up to U16_MAX bytes * per sample in total (rounded down to 8 byte boundary). */ size = min_t(size_t, U16_MAX - header_size, event->attr.aux_sample_size); size = rounddown(size, 8); size = perf_prepare_sample_aux(event, data, size); WARN_ON_ONCE(size + header_size > U16_MAX); data->dyn_size += size + sizeof(u64); /* size above */ data->sample_flags |= PERF_SAMPLE_AUX; } } void perf_prepare_header(struct perf_event_header *header, struct perf_sample_data *data, struct perf_event *event, struct pt_regs *regs) { header->type = PERF_RECORD_SAMPLE; header->size = perf_sample_data_size(data, event); header->misc = perf_misc_flags(regs); /* * If you're adding more sample types here, you likely need to do * something about the overflowing header::size, like repurpose the * lowest 3 bits of size, which should be always zero at the moment. * This raises a more important question, do we really need 512k sized * samples and why, so good argumentation is in order for whatever you * do here next. */ WARN_ON_ONCE(header->size & 7); } static __always_inline int __perf_event_output(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs, int (*output_begin)(struct perf_output_handle *, struct perf_sample_data *, struct perf_event *, unsigned int)) { struct perf_output_handle handle; struct perf_event_header header; int err; /* protect the callchain buffers */ rcu_read_lock(); perf_prepare_sample(data, event, regs); perf_prepare_header(&header, data, event, regs); err = output_begin(&handle, data, event, header.size); if (err) goto exit; perf_output_sample(&handle, &header, data, event); perf_output_end(&handle); exit: rcu_read_unlock(); return err; } void perf_event_output_forward(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { __perf_event_output(event, data, regs, perf_output_begin_forward); } void perf_event_output_backward(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { __perf_event_output(event, data, regs, perf_output_begin_backward); } int perf_event_output(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { return __perf_event_output(event, data, regs, perf_output_begin); } /* * read event_id */ struct perf_read_event { struct perf_event_header header; u32 pid; u32 tid; }; static void perf_event_read_event(struct perf_event *event, struct task_struct *task) { struct perf_output_handle handle; struct perf_sample_data sample; struct perf_read_event read_event = { .header = { .type = PERF_RECORD_READ, .misc = 0, .size = sizeof(read_event) + event->read_size, }, .pid = perf_event_pid(event, task), .tid = perf_event_tid(event, task), }; int ret; perf_event_header__init_id(&read_event.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, read_event.header.size); if (ret) return; perf_output_put(&handle, read_event); perf_output_read(&handle, event); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } typedef void (perf_iterate_f)(struct perf_event *event, void *data); static void perf_iterate_ctx(struct perf_event_context *ctx, perf_iterate_f output, void *data, bool all) { struct perf_event *event; list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { if (!all) { if (event->state < PERF_EVENT_STATE_INACTIVE) continue; if (!event_filter_match(event)) continue; } output(event, data); } } static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) { struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); struct perf_event *event; list_for_each_entry_rcu(event, &pel->list, sb_list) { /* * Skip events that are not fully formed yet; ensure that * if we observe event->ctx, both event and ctx will be * complete enough. See perf_install_in_context(). */ if (!smp_load_acquire(&event->ctx)) continue; if (event->state < PERF_EVENT_STATE_INACTIVE) continue; if (!event_filter_match(event)) continue; output(event, data); } } /* * Iterate all events that need to receive side-band events. * * For new callers; ensure that account_pmu_sb_event() includes * your event, otherwise it might not get delivered. */ static void perf_iterate_sb(perf_iterate_f output, void *data, struct perf_event_context *task_ctx) { struct perf_event_context *ctx; rcu_read_lock(); preempt_disable(); /* * If we have task_ctx != NULL we only notify the task context itself. * The task_ctx is set only for EXIT events before releasing task * context. */ if (task_ctx) { perf_iterate_ctx(task_ctx, output, data, false); goto done; } perf_iterate_sb_cpu(output, data); ctx = rcu_dereference(current->perf_event_ctxp); if (ctx) perf_iterate_ctx(ctx, output, data, false); done: preempt_enable(); rcu_read_unlock(); } /* * Clear all file-based filters at exec, they'll have to be * re-instated when/if these objects are mmapped again. */ static void perf_event_addr_filters_exec(struct perf_event *event, void *data) { struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); struct perf_addr_filter *filter; unsigned int restart = 0, count = 0; unsigned long flags; if (!has_addr_filter(event)) return; raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { if (filter->path.dentry) { event->addr_filter_ranges[count].start = 0; event->addr_filter_ranges[count].size = 0; restart++; } count++; } if (restart) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); if (restart) perf_event_stop(event, 1); } void perf_event_exec(void) { struct perf_event_context *ctx; ctx = perf_pin_task_context(current); if (!ctx) return; perf_event_enable_on_exec(ctx); perf_event_remove_on_exec(ctx); perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true); perf_unpin_context(ctx); put_ctx(ctx); } struct remote_output { struct perf_buffer *rb; int err; }; static void __perf_event_output_stop(struct perf_event *event, void *data) { struct perf_event *parent = event->parent; struct remote_output *ro = data; struct perf_buffer *rb = ro->rb; struct stop_event_data sd = { .event = event, }; if (!has_aux(event)) return; if (!parent) parent = event; /* * In case of inheritance, it will be the parent that links to the * ring-buffer, but it will be the child that's actually using it. * * We are using event::rb to determine if the event should be stopped, * however this may race with ring_buffer_attach() (through set_output), * which will make us skip the event that actually needs to be stopped. * So ring_buffer_attach() has to stop an aux event before re-assigning * its rb pointer. */ if (rcu_dereference(parent->rb) == rb) ro->err = __perf_event_stop(&sd); } static int __perf_pmu_output_stop(void *info) { struct perf_event *event = info; struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct remote_output ro = { .rb = event->rb, }; rcu_read_lock(); perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); if (cpuctx->task_ctx) perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, &ro, false); rcu_read_unlock(); return ro.err; } static void perf_pmu_output_stop(struct perf_event *event) { struct perf_event *iter; int err, cpu; restart: rcu_read_lock(); list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { /* * For per-CPU events, we need to make sure that neither they * nor their children are running; for cpu==-1 events it's * sufficient to stop the event itself if it's active, since * it can't have children. */ cpu = iter->cpu; if (cpu == -1) cpu = READ_ONCE(iter->oncpu); if (cpu == -1) continue; err = cpu_function_call(cpu, __perf_pmu_output_stop, event); if (err == -EAGAIN) { rcu_read_unlock(); goto restart; } } rcu_read_unlock(); } /* * task tracking -- fork/exit * * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task */ struct perf_task_event { struct task_struct *task; struct perf_event_context *task_ctx; struct { struct perf_event_header header; u32 pid; u32 ppid; u32 tid; u32 ptid; u64 time; } event_id; }; static int perf_event_task_match(struct perf_event *event) { return event->attr.comm || event->attr.mmap || event->attr.mmap2 || event->attr.mmap_data || event->attr.task; } static void perf_event_task_output(struct perf_event *event, void *data) { struct perf_task_event *task_event = data; struct perf_output_handle handle; struct perf_sample_data sample; struct task_struct *task = task_event->task; int ret, size = task_event->event_id.header.size; if (!perf_event_task_match(event)) return; perf_event_header__init_id(&task_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, task_event->event_id.header.size); if (ret) goto out; task_event->event_id.pid = perf_event_pid(event, task); task_event->event_id.tid = perf_event_tid(event, task); if (task_event->event_id.header.type == PERF_RECORD_EXIT) { task_event->event_id.ppid = perf_event_pid(event, task->real_parent); task_event->event_id.ptid = perf_event_pid(event, task->real_parent); } else { /* PERF_RECORD_FORK */ task_event->event_id.ppid = perf_event_pid(event, current); task_event->event_id.ptid = perf_event_tid(event, current); } task_event->event_id.time = perf_event_clock(event); perf_output_put(&handle, task_event->event_id); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: task_event->event_id.header.size = size; } static void perf_event_task(struct task_struct *task, struct perf_event_context *task_ctx, int new) { struct perf_task_event task_event; if (!atomic_read(&nr_comm_events) && !atomic_read(&nr_mmap_events) && !atomic_read(&nr_task_events)) return; task_event = (struct perf_task_event){ .task = task, .task_ctx = task_ctx, .event_id = { .header = { .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, .misc = 0, .size = sizeof(task_event.event_id), }, /* .pid */ /* .ppid */ /* .tid */ /* .ptid */ /* .time */ }, }; perf_iterate_sb(perf_event_task_output, &task_event, task_ctx); } void perf_event_fork(struct task_struct *task) { perf_event_task(task, NULL, 1); perf_event_namespaces(task); } /* * comm tracking */ struct perf_comm_event { struct task_struct *task; char *comm; int comm_size; struct { struct perf_event_header header; u32 pid; u32 tid; } event_id; }; static int perf_event_comm_match(struct perf_event *event) { return event->attr.comm; } static void perf_event_comm_output(struct perf_event *event, void *data) { struct perf_comm_event *comm_event = data; struct perf_output_handle handle; struct perf_sample_data sample; int size = comm_event->event_id.header.size; int ret; if (!perf_event_comm_match(event)) return; perf_event_header__init_id(&comm_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, comm_event->event_id.header.size); if (ret) goto out; comm_event->event_id.pid = perf_event_pid(event, comm_event->task); comm_event->event_id.tid = perf_event_tid(event, comm_event->task); perf_output_put(&handle, comm_event->event_id); __output_copy(&handle, comm_event->comm, comm_event->comm_size); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: comm_event->event_id.header.size = size; } static void perf_event_comm_event(struct perf_comm_event *comm_event) { char comm[TASK_COMM_LEN]; unsigned int size; memset(comm, 0, sizeof(comm)); strscpy(comm, comm_event->task->comm, sizeof(comm)); size = ALIGN(strlen(comm)+1, sizeof(u64)); comm_event->comm = comm; comm_event->comm_size = size; comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; perf_iterate_sb(perf_event_comm_output, comm_event, NULL); } void perf_event_comm(struct task_struct *task, bool exec) { struct perf_comm_event comm_event; if (!atomic_read(&nr_comm_events)) return; comm_event = (struct perf_comm_event){ .task = task, /* .comm */ /* .comm_size */ .event_id = { .header = { .type = PERF_RECORD_COMM, .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, /* .size */ }, /* .pid */ /* .tid */ }, }; perf_event_comm_event(&comm_event); } /* * namespaces tracking */ struct perf_namespaces_event { struct task_struct *task; struct { struct perf_event_header header; u32 pid; u32 tid; u64 nr_namespaces; struct perf_ns_link_info link_info[NR_NAMESPACES]; } event_id; }; static int perf_event_namespaces_match(struct perf_event *event) { return event->attr.namespaces; } static void perf_event_namespaces_output(struct perf_event *event, void *data) { struct perf_namespaces_event *namespaces_event = data; struct perf_output_handle handle; struct perf_sample_data sample; u16 header_size = namespaces_event->event_id.header.size; int ret; if (!perf_event_namespaces_match(event)) return; perf_event_header__init_id(&namespaces_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, namespaces_event->event_id.header.size); if (ret) goto out; namespaces_event->event_id.pid = perf_event_pid(event, namespaces_event->task); namespaces_event->event_id.tid = perf_event_tid(event, namespaces_event->task); perf_output_put(&handle, namespaces_event->event_id); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: namespaces_event->event_id.header.size = header_size; } static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, struct task_struct *task, const struct proc_ns_operations *ns_ops) { struct path ns_path; struct inode *ns_inode; int error; error = ns_get_path(&ns_path, task, ns_ops); if (!error) { ns_inode = ns_path.dentry->d_inode; ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); ns_link_info->ino = ns_inode->i_ino; path_put(&ns_path); } } void perf_event_namespaces(struct task_struct *task) { struct perf_namespaces_event namespaces_event; struct perf_ns_link_info *ns_link_info; if (!atomic_read(&nr_namespaces_events)) return; namespaces_event = (struct perf_namespaces_event){ .task = task, .event_id = { .header = { .type = PERF_RECORD_NAMESPACES, .misc = 0, .size = sizeof(namespaces_event.event_id), }, /* .pid */ /* .tid */ .nr_namespaces = NR_NAMESPACES, /* .link_info[NR_NAMESPACES] */ }, }; ns_link_info = namespaces_event.event_id.link_info; perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], task, &mntns_operations); #ifdef CONFIG_USER_NS perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], task, &userns_operations); #endif #ifdef CONFIG_NET_NS perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], task, &netns_operations); #endif #ifdef CONFIG_UTS_NS perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], task, &utsns_operations); #endif #ifdef CONFIG_IPC_NS perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], task, &ipcns_operations); #endif #ifdef CONFIG_PID_NS perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], task, &pidns_operations); #endif #ifdef CONFIG_CGROUPS perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], task, &cgroupns_operations); #endif perf_iterate_sb(perf_event_namespaces_output, &namespaces_event, NULL); } /* * cgroup tracking */ #ifdef CONFIG_CGROUP_PERF struct perf_cgroup_event { char *path; int path_size; struct { struct perf_event_header header; u64 id; char path[]; } event_id; }; static int perf_event_cgroup_match(struct perf_event *event) { return event->attr.cgroup; } static void perf_event_cgroup_output(struct perf_event *event, void *data) { struct perf_cgroup_event *cgroup_event = data; struct perf_output_handle handle; struct perf_sample_data sample; u16 header_size = cgroup_event->event_id.header.size; int ret; if (!perf_event_cgroup_match(event)) return; perf_event_header__init_id(&cgroup_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, cgroup_event->event_id.header.size); if (ret) goto out; perf_output_put(&handle, cgroup_event->event_id); __output_copy(&handle, cgroup_event->path, cgroup_event->path_size); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: cgroup_event->event_id.header.size = header_size; } static void perf_event_cgroup(struct cgroup *cgrp) { struct perf_cgroup_event cgroup_event; char path_enomem[16] = "//enomem"; char *pathname; size_t size; if (!atomic_read(&nr_cgroup_events)) return; cgroup_event = (struct perf_cgroup_event){ .event_id = { .header = { .type = PERF_RECORD_CGROUP, .misc = 0, .size = sizeof(cgroup_event.event_id), }, .id = cgroup_id(cgrp), }, }; pathname = kmalloc(PATH_MAX, GFP_KERNEL); if (pathname == NULL) { cgroup_event.path = path_enomem; } else { /* just to be sure to have enough space for alignment */ cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64)); cgroup_event.path = pathname; } /* * Since our buffer works in 8 byte units we need to align our string * size to a multiple of 8. However, we must guarantee the tail end is * zero'd out to avoid leaking random bits to userspace. */ size = strlen(cgroup_event.path) + 1; while (!IS_ALIGNED(size, sizeof(u64))) cgroup_event.path[size++] = '\0'; cgroup_event.event_id.header.size += size; cgroup_event.path_size = size; perf_iterate_sb(perf_event_cgroup_output, &cgroup_event, NULL); kfree(pathname); } #endif /* * mmap tracking */ struct perf_mmap_event { struct vm_area_struct *vma; const char *file_name; int file_size; int maj, min; u64 ino; u64 ino_generation; u32 prot, flags; u8 build_id[BUILD_ID_SIZE_MAX]; u32 build_id_size; struct { struct perf_event_header header; u32 pid; u32 tid; u64 start; u64 len; u64 pgoff; } event_id; }; static int perf_event_mmap_match(struct perf_event *event, void *data) { struct perf_mmap_event *mmap_event = data; struct vm_area_struct *vma = mmap_event->vma; int executable = vma->vm_flags & VM_EXEC; return (!executable && event->attr.mmap_data) || (executable && (event->attr.mmap || event->attr.mmap2)); } static void perf_event_mmap_output(struct perf_event *event, void *data) { struct perf_mmap_event *mmap_event = data; struct perf_output_handle handle; struct perf_sample_data sample; int size = mmap_event->event_id.header.size; u32 type = mmap_event->event_id.header.type; bool use_build_id; int ret; if (!perf_event_mmap_match(event, data)) return; if (event->attr.mmap2) { mmap_event->event_id.header.type = PERF_RECORD_MMAP2; mmap_event->event_id.header.size += sizeof(mmap_event->maj); mmap_event->event_id.header.size += sizeof(mmap_event->min); mmap_event->event_id.header.size += sizeof(mmap_event->ino); mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); mmap_event->event_id.header.size += sizeof(mmap_event->prot); mmap_event->event_id.header.size += sizeof(mmap_event->flags); } perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, mmap_event->event_id.header.size); if (ret) goto out; mmap_event->event_id.pid = perf_event_pid(event, current); mmap_event->event_id.tid = perf_event_tid(event, current); use_build_id = event->attr.build_id && mmap_event->build_id_size; if (event->attr.mmap2 && use_build_id) mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID; perf_output_put(&handle, mmap_event->event_id); if (event->attr.mmap2) { if (use_build_id) { u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 }; __output_copy(&handle, size, 4); __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX); } else { perf_output_put(&handle, mmap_event->maj); perf_output_put(&handle, mmap_event->min); perf_output_put(&handle, mmap_event->ino); perf_output_put(&handle, mmap_event->ino_generation); } perf_output_put(&handle, mmap_event->prot); perf_output_put(&handle, mmap_event->flags); } __output_copy(&handle, mmap_event->file_name, mmap_event->file_size); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); out: mmap_event->event_id.header.size = size; mmap_event->event_id.header.type = type; } static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) { struct vm_area_struct *vma = mmap_event->vma; struct file *file = vma->vm_file; int maj = 0, min = 0; u64 ino = 0, gen = 0; u32 prot = 0, flags = 0; unsigned int size; char tmp[16]; char *buf = NULL; char *name = NULL; if (vma->vm_flags & VM_READ) prot |= PROT_READ; if (vma->vm_flags & VM_WRITE) prot |= PROT_WRITE; if (vma->vm_flags & VM_EXEC) prot |= PROT_EXEC; if (vma->vm_flags & VM_MAYSHARE) flags = MAP_SHARED; else flags = MAP_PRIVATE; if (vma->vm_flags & VM_LOCKED) flags |= MAP_LOCKED; if (is_vm_hugetlb_page(vma)) flags |= MAP_HUGETLB; if (file) { struct inode *inode; dev_t dev; buf = kmalloc(PATH_MAX, GFP_KERNEL); if (!buf) { name = "//enomem"; goto cpy_name; } /* * d_path() works from the end of the rb backwards, so we * need to add enough zero bytes after the string to handle * the 64bit alignment we do later. */ name = file_path(file, buf, PATH_MAX - sizeof(u64)); if (IS_ERR(name)) { name = "//toolong"; goto cpy_name; } inode = file_inode(vma->vm_file); dev = inode->i_sb->s_dev; ino = inode->i_ino; gen = inode->i_generation; maj = MAJOR(dev); min = MINOR(dev); goto got_name; } else { if (vma->vm_ops && vma->vm_ops->name) name = (char *) vma->vm_ops->name(vma); if (!name) name = (char *)arch_vma_name(vma); if (!name) { if (vma_is_initial_heap(vma)) name = "[heap]"; else if (vma_is_initial_stack(vma)) name = "[stack]"; else name = "//anon"; } } cpy_name: strscpy(tmp, name, sizeof(tmp)); name = tmp; got_name: /* * Since our buffer works in 8 byte units we need to align our string * size to a multiple of 8. However, we must guarantee the tail end is * zero'd out to avoid leaking random bits to userspace. */ size = strlen(name)+1; while (!IS_ALIGNED(size, sizeof(u64))) name[size++] = '\0'; mmap_event->file_name = name; mmap_event->file_size = size; mmap_event->maj = maj; mmap_event->min = min; mmap_event->ino = ino; mmap_event->ino_generation = gen; mmap_event->prot = prot; mmap_event->flags = flags; if (!(vma->vm_flags & VM_EXEC)) mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; if (atomic_read(&nr_build_id_events)) build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size); perf_iterate_sb(perf_event_mmap_output, mmap_event, NULL); kfree(buf); } /* * Check whether inode and address range match filter criteria. */ static bool perf_addr_filter_match(struct perf_addr_filter *filter, struct file *file, unsigned long offset, unsigned long size) { /* d_inode(NULL) won't be equal to any mapped user-space file */ if (!filter->path.dentry) return false; if (d_inode(filter->path.dentry) != file_inode(file)) return false; if (filter->offset > offset + size) return false; if (filter->offset + filter->size < offset) return false; return true; } static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter, struct vm_area_struct *vma, struct perf_addr_filter_range *fr) { unsigned long vma_size = vma->vm_end - vma->vm_start; unsigned long off = vma->vm_pgoff << PAGE_SHIFT; struct file *file = vma->vm_file; if (!perf_addr_filter_match(filter, file, off, vma_size)) return false; if (filter->offset < off) { fr->start = vma->vm_start; fr->size = min(vma_size, filter->size - (off - filter->offset)); } else { fr->start = vma->vm_start + filter->offset - off; fr->size = min(vma->vm_end - fr->start, filter->size); } return true; } static void __perf_addr_filters_adjust(struct perf_event *event, void *data) { struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); struct vm_area_struct *vma = data; struct perf_addr_filter *filter; unsigned int restart = 0, count = 0; unsigned long flags; if (!has_addr_filter(event)) return; if (!vma->vm_file) return; raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { if (perf_addr_filter_vma_adjust(filter, vma, &event->addr_filter_ranges[count])) restart++; count++; } if (restart) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); if (restart) perf_event_stop(event, 1); } /* * Adjust all task's events' filters to the new vma */ static void perf_addr_filters_adjust(struct vm_area_struct *vma) { struct perf_event_context *ctx; /* * Data tracing isn't supported yet and as such there is no need * to keep track of anything that isn't related to executable code: */ if (!(vma->vm_flags & VM_EXEC)) return; rcu_read_lock(); ctx = rcu_dereference(current->perf_event_ctxp); if (ctx) perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); rcu_read_unlock(); } void perf_event_mmap(struct vm_area_struct *vma) { struct perf_mmap_event mmap_event; if (!atomic_read(&nr_mmap_events)) return; mmap_event = (struct perf_mmap_event){ .vma = vma, /* .file_name */ /* .file_size */ .event_id = { .header = { .type = PERF_RECORD_MMAP, .misc = PERF_RECORD_MISC_USER, /* .size */ }, /* .pid */ /* .tid */ .start = vma->vm_start, .len = vma->vm_end - vma->vm_start, .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, }, /* .maj (attr_mmap2 only) */ /* .min (attr_mmap2 only) */ /* .ino (attr_mmap2 only) */ /* .ino_generation (attr_mmap2 only) */ /* .prot (attr_mmap2 only) */ /* .flags (attr_mmap2 only) */ }; perf_addr_filters_adjust(vma); perf_event_mmap_event(&mmap_event); } void perf_event_aux_event(struct perf_event *event, unsigned long head, unsigned long size, u64 flags) { struct perf_output_handle handle; struct perf_sample_data sample; struct perf_aux_event { struct perf_event_header header; u64 offset; u64 size; u64 flags; } rec = { .header = { .type = PERF_RECORD_AUX, .misc = 0, .size = sizeof(rec), }, .offset = head, .size = size, .flags = flags, }; int ret; perf_event_header__init_id(&rec.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, rec.header.size); if (ret) return; perf_output_put(&handle, rec); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } /* * Lost/dropped samples logging */ void perf_log_lost_samples(struct perf_event *event, u64 lost) { struct perf_output_handle handle; struct perf_sample_data sample; int ret; struct { struct perf_event_header header; u64 lost; } lost_samples_event = { .header = { .type = PERF_RECORD_LOST_SAMPLES, .misc = 0, .size = sizeof(lost_samples_event), }, .lost = lost, }; perf_event_header__init_id(&lost_samples_event.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, lost_samples_event.header.size); if (ret) return; perf_output_put(&handle, lost_samples_event); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } /* * context_switch tracking */ struct perf_switch_event { struct task_struct *task; struct task_struct *next_prev; struct { struct perf_event_header header; u32 next_prev_pid; u32 next_prev_tid; } event_id; }; static int perf_event_switch_match(struct perf_event *event) { return event->attr.context_switch; } static void perf_event_switch_output(struct perf_event *event, void *data) { struct perf_switch_event *se = data; struct perf_output_handle handle; struct perf_sample_data sample; int ret; if (!perf_event_switch_match(event)) return; /* Only CPU-wide events are allowed to see next/prev pid/tid */ if (event->ctx->task) { se->event_id.header.type = PERF_RECORD_SWITCH; se->event_id.header.size = sizeof(se->event_id.header); } else { se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; se->event_id.header.size = sizeof(se->event_id); se->event_id.next_prev_pid = perf_event_pid(event, se->next_prev); se->event_id.next_prev_tid = perf_event_tid(event, se->next_prev); } perf_event_header__init_id(&se->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size); if (ret) return; if (event->ctx->task) perf_output_put(&handle, se->event_id.header); else perf_output_put(&handle, se->event_id); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } static void perf_event_switch(struct task_struct *task, struct task_struct *next_prev, bool sched_in) { struct perf_switch_event switch_event; /* N.B. caller checks nr_switch_events != 0 */ switch_event = (struct perf_switch_event){ .task = task, .next_prev = next_prev, .event_id = { .header = { /* .type */ .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, /* .size */ }, /* .next_prev_pid */ /* .next_prev_tid */ }, }; if (!sched_in && task->on_rq) { switch_event.event_id.header.misc |= PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; } perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); } /* * IRQ throttle logging */ static void perf_log_throttle(struct perf_event *event, int enable) { struct perf_output_handle handle; struct perf_sample_data sample; int ret; struct { struct perf_event_header header; u64 time; u64 id; u64 stream_id; } throttle_event = { .header = { .type = PERF_RECORD_THROTTLE, .misc = 0, .size = sizeof(throttle_event), }, .time = perf_event_clock(event), .id = primary_event_id(event), .stream_id = event->id, }; if (enable) throttle_event.header.type = PERF_RECORD_UNTHROTTLE; perf_event_header__init_id(&throttle_event.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, throttle_event.header.size); if (ret) return; perf_output_put(&handle, throttle_event); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } /* * ksymbol register/unregister tracking */ struct perf_ksymbol_event { const char *name; int name_len; struct { struct perf_event_header header; u64 addr; u32 len; u16 ksym_type; u16 flags; } event_id; }; static int perf_event_ksymbol_match(struct perf_event *event) { return event->attr.ksymbol; } static void perf_event_ksymbol_output(struct perf_event *event, void *data) { struct perf_ksymbol_event *ksymbol_event = data; struct perf_output_handle handle; struct perf_sample_data sample; int ret; if (!perf_event_ksymbol_match(event)) return; perf_event_header__init_id(&ksymbol_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, ksymbol_event->event_id.header.size); if (ret) return; perf_output_put(&handle, ksymbol_event->event_id); __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister, const char *sym) { struct perf_ksymbol_event ksymbol_event; char name[KSYM_NAME_LEN]; u16 flags = 0; int name_len; if (!atomic_read(&nr_ksymbol_events)) return; if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX || ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN) goto err; strscpy(name, sym, KSYM_NAME_LEN); name_len = strlen(name) + 1; while (!IS_ALIGNED(name_len, sizeof(u64))) name[name_len++] = '\0'; BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64)); if (unregister) flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER; ksymbol_event = (struct perf_ksymbol_event){ .name = name, .name_len = name_len, .event_id = { .header = { .type = PERF_RECORD_KSYMBOL, .size = sizeof(ksymbol_event.event_id) + name_len, }, .addr = addr, .len = len, .ksym_type = ksym_type, .flags = flags, }, }; perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL); return; err: WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type); } /* * bpf program load/unload tracking */ struct perf_bpf_event { struct bpf_prog *prog; struct { struct perf_event_header header; u16 type; u16 flags; u32 id; u8 tag[BPF_TAG_SIZE]; } event_id; }; static int perf_event_bpf_match(struct perf_event *event) { return event->attr.bpf_event; } static void perf_event_bpf_output(struct perf_event *event, void *data) { struct perf_bpf_event *bpf_event = data; struct perf_output_handle handle; struct perf_sample_data sample; int ret; if (!perf_event_bpf_match(event)) return; perf_event_header__init_id(&bpf_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, bpf_event->event_id.header.size); if (ret) return; perf_output_put(&handle, bpf_event->event_id); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, enum perf_bpf_event_type type) { bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD; int i; perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, (u64)(unsigned long)prog->bpf_func, prog->jited_len, unregister, prog->aux->ksym.name); for (i = 1; i < prog->aux->func_cnt; i++) { struct bpf_prog *subprog = prog->aux->func[i]; perf_event_ksymbol( PERF_RECORD_KSYMBOL_TYPE_BPF, (u64)(unsigned long)subprog->bpf_func, subprog->jited_len, unregister, subprog->aux->ksym.name); } } void perf_event_bpf_event(struct bpf_prog *prog, enum perf_bpf_event_type type, u16 flags) { struct perf_bpf_event bpf_event; switch (type) { case PERF_BPF_EVENT_PROG_LOAD: case PERF_BPF_EVENT_PROG_UNLOAD: if (atomic_read(&nr_ksymbol_events)) perf_event_bpf_emit_ksymbols(prog, type); break; default: return; } if (!atomic_read(&nr_bpf_events)) return; bpf_event = (struct perf_bpf_event){ .prog = prog, .event_id = { .header = { .type = PERF_RECORD_BPF_EVENT, .size = sizeof(bpf_event.event_id), }, .type = type, .flags = flags, .id = prog->aux->id, }, }; BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64)); memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE); perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL); } struct perf_text_poke_event { const void *old_bytes; const void *new_bytes; size_t pad; u16 old_len; u16 new_len; struct { struct perf_event_header header; u64 addr; } event_id; }; static int perf_event_text_poke_match(struct perf_event *event) { return event->attr.text_poke; } static void perf_event_text_poke_output(struct perf_event *event, void *data) { struct perf_text_poke_event *text_poke_event = data; struct perf_output_handle handle; struct perf_sample_data sample; u64 padding = 0; int ret; if (!perf_event_text_poke_match(event)) return; perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, text_poke_event->event_id.header.size); if (ret) return; perf_output_put(&handle, text_poke_event->event_id); perf_output_put(&handle, text_poke_event->old_len); perf_output_put(&handle, text_poke_event->new_len); __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len); __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len); if (text_poke_event->pad) __output_copy(&handle, &padding, text_poke_event->pad); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } void perf_event_text_poke(const void *addr, const void *old_bytes, size_t old_len, const void *new_bytes, size_t new_len) { struct perf_text_poke_event text_poke_event; size_t tot, pad; if (!atomic_read(&nr_text_poke_events)) return; tot = sizeof(text_poke_event.old_len) + old_len; tot += sizeof(text_poke_event.new_len) + new_len; pad = ALIGN(tot, sizeof(u64)) - tot; text_poke_event = (struct perf_text_poke_event){ .old_bytes = old_bytes, .new_bytes = new_bytes, .pad = pad, .old_len = old_len, .new_len = new_len, .event_id = { .header = { .type = PERF_RECORD_TEXT_POKE, .misc = PERF_RECORD_MISC_KERNEL, .size = sizeof(text_poke_event.event_id) + tot + pad, }, .addr = (unsigned long)addr, }, }; perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL); } void perf_event_itrace_started(struct perf_event *event) { event->attach_state |= PERF_ATTACH_ITRACE; } static void perf_log_itrace_start(struct perf_event *event) { struct perf_output_handle handle; struct perf_sample_data sample; struct perf_aux_event { struct perf_event_header header; u32 pid; u32 tid; } rec; int ret; if (event->parent) event = event->parent; if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || event->attach_state & PERF_ATTACH_ITRACE) return; rec.header.type = PERF_RECORD_ITRACE_START; rec.header.misc = 0; rec.header.size = sizeof(rec); rec.pid = perf_event_pid(event, current); rec.tid = perf_event_tid(event, current); perf_event_header__init_id(&rec.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, rec.header.size); if (ret) return; perf_output_put(&handle, rec); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } void perf_report_aux_output_id(struct perf_event *event, u64 hw_id) { struct perf_output_handle handle; struct perf_sample_data sample; struct perf_aux_event { struct perf_event_header header; u64 hw_id; } rec; int ret; if (event->parent) event = event->parent; rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID; rec.header.misc = 0; rec.header.size = sizeof(rec); rec.hw_id = hw_id; perf_event_header__init_id(&rec.header, &sample, event); ret = perf_output_begin(&handle, &sample, event, rec.header.size); if (ret) return; perf_output_put(&handle, rec); perf_event__output_id_sample(event, &handle, &sample); perf_output_end(&handle); } EXPORT_SYMBOL_GPL(perf_report_aux_output_id); static int __perf_event_account_interrupt(struct perf_event *event, int throttle) { struct hw_perf_event *hwc = &event->hw; int ret = 0; u64 seq; seq = __this_cpu_read(perf_throttled_seq); if (seq != hwc->interrupts_seq) { hwc->interrupts_seq = seq; hwc->interrupts = 1; } else { hwc->interrupts++; if (unlikely(throttle && hwc->interrupts > max_samples_per_tick)) { __this_cpu_inc(perf_throttled_count); tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); hwc->interrupts = MAX_INTERRUPTS; perf_log_throttle(event, 0); ret = 1; } } if (event->attr.freq) { u64 now = perf_clock(); s64 delta = now - hwc->freq_time_stamp; hwc->freq_time_stamp = now; if (delta > 0 && delta < 2*TICK_NSEC) perf_adjust_period(event, delta, hwc->last_period, true); } return ret; } int perf_event_account_interrupt(struct perf_event *event) { return __perf_event_account_interrupt(event, 1); } static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs) { /* * Due to interrupt latency (AKA "skid"), we may enter the * kernel before taking an overflow, even if the PMU is only * counting user events. */ if (event->attr.exclude_kernel && !user_mode(regs)) return false; return true; } #ifdef CONFIG_BPF_SYSCALL static int bpf_overflow_handler(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { struct bpf_perf_event_data_kern ctx = { .data = data, .event = event, }; struct bpf_prog *prog; int ret = 0; ctx.regs = perf_arch_bpf_user_pt_regs(regs); if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) goto out; rcu_read_lock(); prog = READ_ONCE(event->prog); if (prog) { perf_prepare_sample(data, event, regs); ret = bpf_prog_run(prog, &ctx); } rcu_read_unlock(); out: __this_cpu_dec(bpf_prog_active); return ret; } static inline int perf_event_set_bpf_handler(struct perf_event *event, struct bpf_prog *prog, u64 bpf_cookie) { if (event->overflow_handler_context) /* hw breakpoint or kernel counter */ return -EINVAL; if (event->prog) return -EEXIST; if (prog->type != BPF_PROG_TYPE_PERF_EVENT) return -EINVAL; if (event->attr.precise_ip && prog->call_get_stack && (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) || event->attr.exclude_callchain_kernel || event->attr.exclude_callchain_user)) { /* * On perf_event with precise_ip, calling bpf_get_stack() * may trigger unwinder warnings and occasional crashes. * bpf_get_[stack|stackid] works around this issue by using * callchain attached to perf_sample_data. If the * perf_event does not full (kernel and user) callchain * attached to perf_sample_data, do not allow attaching BPF * program that calls bpf_get_[stack|stackid]. */ return -EPROTO; } event->prog = prog; event->bpf_cookie = bpf_cookie; return 0; } static inline void perf_event_free_bpf_handler(struct perf_event *event) { struct bpf_prog *prog = event->prog; if (!prog) return; event->prog = NULL; bpf_prog_put(prog); } #else static inline int bpf_overflow_handler(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { return 1; } static inline int perf_event_set_bpf_handler(struct perf_event *event, struct bpf_prog *prog, u64 bpf_cookie) { return -EOPNOTSUPP; } static inline void perf_event_free_bpf_handler(struct perf_event *event) { } #endif /* * Generic event overflow handling, sampling. */ static int __perf_event_overflow(struct perf_event *event, int throttle, struct perf_sample_data *data, struct pt_regs *regs) { int events = atomic_read(&event->event_limit); int ret = 0; /* * Non-sampling counters might still use the PMI to fold short * hardware counters, ignore those. */ if (unlikely(!is_sampling_event(event))) return 0; ret = __perf_event_account_interrupt(event, throttle); if (event->prog && event->prog->type == BPF_PROG_TYPE_PERF_EVENT && !bpf_overflow_handler(event, data, regs)) return ret; /* * XXX event_limit might not quite work as expected on inherited * events */ event->pending_kill = POLL_IN; if (events && atomic_dec_and_test(&event->event_limit)) { ret = 1; event->pending_kill = POLL_HUP; perf_event_disable_inatomic(event); } if (event->attr.sigtrap) { /* * The desired behaviour of sigtrap vs invalid samples is a bit * tricky; on the one hand, one should not loose the SIGTRAP if * it is the first event, on the other hand, we should also not * trigger the WARN or override the data address. */ bool valid_sample = sample_is_allowed(event, regs); unsigned int pending_id = 1; enum task_work_notify_mode notify_mode; if (regs) pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1; notify_mode = in_nmi() ? TWA_NMI_CURRENT : TWA_RESUME; if (!event->pending_work && !task_work_add(current, &event->pending_task, notify_mode)) { event->pending_work = pending_id; local_inc(&event->ctx->nr_pending); event->pending_addr = 0; if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR)) event->pending_addr = data->addr; } else if (event->attr.exclude_kernel && valid_sample) { /* * Should not be able to return to user space without * consuming pending_work; with exceptions: * * 1. Where !exclude_kernel, events can overflow again * in the kernel without returning to user space. * * 2. Events that can overflow again before the IRQ- * work without user space progress (e.g. hrtimer). * To approximate progress (with false negatives), * check 32-bit hash of the current IP. */ WARN_ON_ONCE(event->pending_work != pending_id); } } READ_ONCE(event->overflow_handler)(event, data, regs); if (*perf_event_fasync(event) && event->pending_kill) { event->pending_wakeup = 1; irq_work_queue(&event->pending_irq); } return ret; } int perf_event_overflow(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { return __perf_event_overflow(event, 1, data, regs); } /* * Generic software event infrastructure */ struct swevent_htable { struct swevent_hlist *swevent_hlist; struct mutex hlist_mutex; int hlist_refcount; }; static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); /* * We directly increment event->count and keep a second value in * event->hw.period_left to count intervals. This period event * is kept in the range [-sample_period, 0] so that we can use the * sign as trigger. */ u64 perf_swevent_set_period(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; u64 period = hwc->last_period; u64 nr, offset; s64 old, val; hwc->last_period = hwc->sample_period; old = local64_read(&hwc->period_left); do { val = old; if (val < 0) return 0; nr = div64_u64(period + val, period); offset = nr * period; val -= offset; } while (!local64_try_cmpxchg(&hwc->period_left, &old, val)); return nr; } static void perf_swevent_overflow(struct perf_event *event, u64 overflow, struct perf_sample_data *data, struct pt_regs *regs) { struct hw_perf_event *hwc = &event->hw; int throttle = 0; if (!overflow) overflow = perf_swevent_set_period(event); if (hwc->interrupts == MAX_INTERRUPTS) return; for (; overflow; overflow--) { if (__perf_event_overflow(event, throttle, data, regs)) { /* * We inhibit the overflow from happening when * hwc->interrupts == MAX_INTERRUPTS. */ break; } throttle = 1; } } static void perf_swevent_event(struct perf_event *event, u64 nr, struct perf_sample_data *data, struct pt_regs *regs) { struct hw_perf_event *hwc = &event->hw; local64_add(nr, &event->count); if (!regs) return; if (!is_sampling_event(event)) return; if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { data->period = nr; return perf_swevent_overflow(event, 1, data, regs); } else data->period = event->hw.last_period; if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) return perf_swevent_overflow(event, 1, data, regs); if (local64_add_negative(nr, &hwc->period_left)) return; perf_swevent_overflow(event, 0, data, regs); } static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs) { if (event->hw.state & PERF_HES_STOPPED) return 1; if (regs) { if (event->attr.exclude_user && user_mode(regs)) return 1; if (event->attr.exclude_kernel && !user_mode(regs)) return 1; } return 0; } static int perf_swevent_match(struct perf_event *event, enum perf_type_id type, u32 event_id, struct perf_sample_data *data, struct pt_regs *regs) { if (event->attr.type != type) return 0; if (event->attr.config != event_id) return 0; if (perf_exclude_event(event, regs)) return 0; return 1; } static inline u64 swevent_hash(u64 type, u32 event_id) { u64 val = event_id | (type << 32); return hash_64(val, SWEVENT_HLIST_BITS); } static inline struct hlist_head * __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) { u64 hash = swevent_hash(type, event_id); return &hlist->heads[hash]; } /* For the read side: events when they trigger */ static inline struct hlist_head * find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) { struct swevent_hlist *hlist; hlist = rcu_dereference(swhash->swevent_hlist); if (!hlist) return NULL; return __find_swevent_head(hlist, type, event_id); } /* For the event head insertion and removal in the hlist */ static inline struct hlist_head * find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) { struct swevent_hlist *hlist; u32 event_id = event->attr.config; u64 type = event->attr.type; /* * Event scheduling is always serialized against hlist allocation * and release. Which makes the protected version suitable here. * The context lock guarantees that. */ hlist = rcu_dereference_protected(swhash->swevent_hlist, lockdep_is_held(&event->ctx->lock)); if (!hlist) return NULL; return __find_swevent_head(hlist, type, event_id); } static void do_perf_sw_event(enum perf_type_id type, u32 event_id, u64 nr, struct perf_sample_data *data, struct pt_regs *regs) { struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); struct perf_event *event; struct hlist_head *head; rcu_read_lock(); head = find_swevent_head_rcu(swhash, type, event_id); if (!head) goto end; hlist_for_each_entry_rcu(event, head, hlist_entry) { if (perf_swevent_match(event, type, event_id, data, regs)) perf_swevent_event(event, nr, data, regs); } end: rcu_read_unlock(); } DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); int perf_swevent_get_recursion_context(void) { return get_recursion_context(current->perf_recursion); } EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); void perf_swevent_put_recursion_context(int rctx) { put_recursion_context(current->perf_recursion, rctx); } void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) { struct perf_sample_data data; if (WARN_ON_ONCE(!regs)) return; perf_sample_data_init(&data, addr, 0); do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); } void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) { int rctx; preempt_disable_notrace(); rctx = perf_swevent_get_recursion_context(); if (unlikely(rctx < 0)) goto fail; ___perf_sw_event(event_id, nr, regs, addr); perf_swevent_put_recursion_context(rctx); fail: preempt_enable_notrace(); } static void perf_swevent_read(struct perf_event *event) { } static int perf_swevent_add(struct perf_event *event, int flags) { struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); struct hw_perf_event *hwc = &event->hw; struct hlist_head *head; if (is_sampling_event(event)) { hwc->last_period = hwc->sample_period; perf_swevent_set_period(event); } hwc->state = !(flags & PERF_EF_START); head = find_swevent_head(swhash, event); if (WARN_ON_ONCE(!head)) return -EINVAL; hlist_add_head_rcu(&event->hlist_entry, head); perf_event_update_userpage(event); return 0; } static void perf_swevent_del(struct perf_event *event, int flags) { hlist_del_rcu(&event->hlist_entry); } static void perf_swevent_start(struct perf_event *event, int flags) { event->hw.state = 0; } static void perf_swevent_stop(struct perf_event *event, int flags) { event->hw.state = PERF_HES_STOPPED; } /* Deref the hlist from the update side */ static inline struct swevent_hlist * swevent_hlist_deref(struct swevent_htable *swhash) { return rcu_dereference_protected(swhash->swevent_hlist, lockdep_is_held(&swhash->hlist_mutex)); } static void swevent_hlist_release(struct swevent_htable *swhash) { struct swevent_hlist *hlist = swevent_hlist_deref(swhash); if (!hlist) return; RCU_INIT_POINTER(swhash->swevent_hlist, NULL); kfree_rcu(hlist, rcu_head); } static void swevent_hlist_put_cpu(int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); mutex_lock(&swhash->hlist_mutex); if (!--swhash->hlist_refcount) swevent_hlist_release(swhash); mutex_unlock(&swhash->hlist_mutex); } static void swevent_hlist_put(void) { int cpu; for_each_possible_cpu(cpu) swevent_hlist_put_cpu(cpu); } static int swevent_hlist_get_cpu(int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); int err = 0; mutex_lock(&swhash->hlist_mutex); if (!swevent_hlist_deref(swhash) && cpumask_test_cpu(cpu, perf_online_mask)) { struct swevent_hlist *hlist; hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); if (!hlist) { err = -ENOMEM; goto exit; } rcu_assign_pointer(swhash->swevent_hlist, hlist); } swhash->hlist_refcount++; exit: mutex_unlock(&swhash->hlist_mutex); return err; } static int swevent_hlist_get(void) { int err, cpu, failed_cpu; mutex_lock(&pmus_lock); for_each_possible_cpu(cpu) { err = swevent_hlist_get_cpu(cpu); if (err) { failed_cpu = cpu; goto fail; } } mutex_unlock(&pmus_lock); return 0; fail: for_each_possible_cpu(cpu) { if (cpu == failed_cpu) break; swevent_hlist_put_cpu(cpu); } mutex_unlock(&pmus_lock); return err; } struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; static void sw_perf_event_destroy(struct perf_event *event) { u64 event_id = event->attr.config; WARN_ON(event->parent); static_key_slow_dec(&perf_swevent_enabled[event_id]); swevent_hlist_put(); } static struct pmu perf_cpu_clock; /* fwd declaration */ static struct pmu perf_task_clock; static int perf_swevent_init(struct perf_event *event) { u64 event_id = event->attr.config; if (event->attr.type != PERF_TYPE_SOFTWARE) return -ENOENT; /* * no branch sampling for software events */ if (has_branch_stack(event)) return -EOPNOTSUPP; switch (event_id) { case PERF_COUNT_SW_CPU_CLOCK: event->attr.type = perf_cpu_clock.type; return -ENOENT; case PERF_COUNT_SW_TASK_CLOCK: event->attr.type = perf_task_clock.type; return -ENOENT; default: break; } if (event_id >= PERF_COUNT_SW_MAX) return -ENOENT; if (!event->parent) { int err; err = swevent_hlist_get(); if (err) return err; static_key_slow_inc(&perf_swevent_enabled[event_id]); event->destroy = sw_perf_event_destroy; } return 0; } static struct pmu perf_swevent = { .task_ctx_nr = perf_sw_context, .capabilities = PERF_PMU_CAP_NO_NMI, .event_init = perf_swevent_init, .add = perf_swevent_add, .del = perf_swevent_del, .start = perf_swevent_start, .stop = perf_swevent_stop, .read = perf_swevent_read, }; #ifdef CONFIG_EVENT_TRACING static void tp_perf_event_destroy(struct perf_event *event) { perf_trace_destroy(event); } static int perf_tp_event_init(struct perf_event *event) { int err; if (event->attr.type != PERF_TYPE_TRACEPOINT) return -ENOENT; /* * no branch sampling for tracepoint events */ if (has_branch_stack(event)) return -EOPNOTSUPP; err = perf_trace_init(event); if (err) return err; event->destroy = tp_perf_event_destroy; return 0; } static struct pmu perf_tracepoint = { .task_ctx_nr = perf_sw_context, .event_init = perf_tp_event_init, .add = perf_trace_add, .del = perf_trace_del, .start = perf_swevent_start, .stop = perf_swevent_stop, .read = perf_swevent_read, }; static int perf_tp_filter_match(struct perf_event *event, struct perf_sample_data *data) { void *record = data->raw->frag.data; /* only top level events have filters set */ if (event->parent) event = event->parent; if (likely(!event->filter) || filter_match_preds(event->filter, record)) return 1; return 0; } static int perf_tp_event_match(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { if (event->hw.state & PERF_HES_STOPPED) return 0; /* * If exclude_kernel, only trace user-space tracepoints (uprobes) */ if (event->attr.exclude_kernel && !user_mode(regs)) return 0; if (!perf_tp_filter_match(event, data)) return 0; return 1; } void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, struct trace_event_call *call, u64 count, struct pt_regs *regs, struct hlist_head *head, struct task_struct *task) { if (bpf_prog_array_valid(call)) { *(struct pt_regs **)raw_data = regs; if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) { perf_swevent_put_recursion_context(rctx); return; } } perf_tp_event(call->event.type, count, raw_data, size, regs, head, rctx, task); } EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); static void __perf_tp_event_target_task(u64 count, void *record, struct pt_regs *regs, struct perf_sample_data *data, struct perf_event *event) { struct trace_entry *entry = record; if (event->attr.config != entry->type) return; /* Cannot deliver synchronous signal to other task. */ if (event->attr.sigtrap) return; if (perf_tp_event_match(event, data, regs)) perf_swevent_event(event, count, data, regs); } static void perf_tp_event_target_task(u64 count, void *record, struct pt_regs *regs, struct perf_sample_data *data, struct perf_event_context *ctx) { unsigned int cpu = smp_processor_id(); struct pmu *pmu = &perf_tracepoint; struct perf_event *event, *sibling; perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) { __perf_tp_event_target_task(count, record, regs, data, event); for_each_sibling_event(sibling, event) __perf_tp_event_target_task(count, record, regs, data, sibling); } perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) { __perf_tp_event_target_task(count, record, regs, data, event); for_each_sibling_event(sibling, event) __perf_tp_event_target_task(count, record, regs, data, sibling); } } void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, struct pt_regs *regs, struct hlist_head *head, int rctx, struct task_struct *task) { struct perf_sample_data data; struct perf_event *event; struct perf_raw_record raw = { .frag = { .size = entry_size, .data = record, }, }; perf_sample_data_init(&data, 0, 0); perf_sample_save_raw_data(&data, &raw); perf_trace_buf_update(record, event_type); hlist_for_each_entry_rcu(event, head, hlist_entry) { if (perf_tp_event_match(event, &data, regs)) { perf_swevent_event(event, count, &data, regs); /* * Here use the same on-stack perf_sample_data, * some members in data are event-specific and * need to be re-computed for different sweveents. * Re-initialize data->sample_flags safely to avoid * the problem that next event skips preparing data * because data->sample_flags is set. */ perf_sample_data_init(&data, 0, 0); perf_sample_save_raw_data(&data, &raw); } } /* * If we got specified a target task, also iterate its context and * deliver this event there too. */ if (task && task != current) { struct perf_event_context *ctx; rcu_read_lock(); ctx = rcu_dereference(task->perf_event_ctxp); if (!ctx) goto unlock; raw_spin_lock(&ctx->lock); perf_tp_event_target_task(count, record, regs, &data, ctx); raw_spin_unlock(&ctx->lock); unlock: rcu_read_unlock(); } perf_swevent_put_recursion_context(rctx); } EXPORT_SYMBOL_GPL(perf_tp_event); #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) /* * Flags in config, used by dynamic PMU kprobe and uprobe * The flags should match following PMU_FORMAT_ATTR(). * * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe * if not set, create kprobe/uprobe * * The following values specify a reference counter (or semaphore in the * terminology of tools like dtrace, systemtap, etc.) Userspace Statically * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset. * * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left */ enum perf_probe_config { PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ PERF_UPROBE_REF_CTR_OFFSET_BITS = 32, PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS, }; PMU_FORMAT_ATTR(retprobe, "config:0"); #endif #ifdef CONFIG_KPROBE_EVENTS static struct attribute *kprobe_attrs[] = { &format_attr_retprobe.attr, NULL, }; static struct attribute_group kprobe_format_group = { .name = "format", .attrs = kprobe_attrs, }; static const struct attribute_group *kprobe_attr_groups[] = { &kprobe_format_group, NULL, }; static int perf_kprobe_event_init(struct perf_event *event); static struct pmu perf_kprobe = { .task_ctx_nr = perf_sw_context, .event_init = perf_kprobe_event_init, .add = perf_trace_add, .del = perf_trace_del, .start = perf_swevent_start, .stop = perf_swevent_stop, .read = perf_swevent_read, .attr_groups = kprobe_attr_groups, }; static int perf_kprobe_event_init(struct perf_event *event) { int err; bool is_retprobe; if (event->attr.type != perf_kprobe.type) return -ENOENT; if (!perfmon_capable()) return -EACCES; /* * no branch sampling for probe events */ if (has_branch_stack(event)) return -EOPNOTSUPP; is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; err = perf_kprobe_init(event, is_retprobe); if (err) return err; event->destroy = perf_kprobe_destroy; return 0; } #endif /* CONFIG_KPROBE_EVENTS */ #ifdef CONFIG_UPROBE_EVENTS PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63"); static struct attribute *uprobe_attrs[] = { &format_attr_retprobe.attr, &format_attr_ref_ctr_offset.attr, NULL, }; static struct attribute_group uprobe_format_group = { .name = "format", .attrs = uprobe_attrs, }; static const struct attribute_group *uprobe_attr_groups[] = { &uprobe_format_group, NULL, }; static int perf_uprobe_event_init(struct perf_event *event); static struct pmu perf_uprobe = { .task_ctx_nr = perf_sw_context, .event_init = perf_uprobe_event_init, .add = perf_trace_add, .del = perf_trace_del, .start = perf_swevent_start, .stop = perf_swevent_stop, .read = perf_swevent_read, .attr_groups = uprobe_attr_groups, }; static int perf_uprobe_event_init(struct perf_event *event) { int err; unsigned long ref_ctr_offset; bool is_retprobe; if (event->attr.type != perf_uprobe.type) return -ENOENT; if (!perfmon_capable()) return -EACCES; /* * no branch sampling for probe events */ if (has_branch_stack(event)) return -EOPNOTSUPP; is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT; err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe); if (err) return err; event->destroy = perf_uprobe_destroy; return 0; } #endif /* CONFIG_UPROBE_EVENTS */ static inline void perf_tp_register(void) { perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); #ifdef CONFIG_KPROBE_EVENTS perf_pmu_register(&perf_kprobe, "kprobe", -1); #endif #ifdef CONFIG_UPROBE_EVENTS perf_pmu_register(&perf_uprobe, "uprobe", -1); #endif } static void perf_event_free_filter(struct perf_event *event) { ftrace_profile_free_filter(event); } /* * returns true if the event is a tracepoint, or a kprobe/upprobe created * with perf_event_open() */ static inline bool perf_event_is_tracing(struct perf_event *event) { if (event->pmu == &perf_tracepoint) return true; #ifdef CONFIG_KPROBE_EVENTS if (event->pmu == &perf_kprobe) return true; #endif #ifdef CONFIG_UPROBE_EVENTS if (event->pmu == &perf_uprobe) return true; #endif return false; } int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, u64 bpf_cookie) { bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp; if (!perf_event_is_tracing(event)) return perf_event_set_bpf_handler(event, prog, bpf_cookie); is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE; is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE; is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; is_syscall_tp = is_syscall_trace_event(event->tp_event); if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp) /* bpf programs can only be attached to u/kprobe or tracepoint */ return -EINVAL; if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) || (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) || (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) return -EINVAL; if (prog->type == BPF_PROG_TYPE_KPROBE && prog->sleepable && !is_uprobe) /* only uprobe programs are allowed to be sleepable */ return -EINVAL; /* Kprobe override only works for kprobes, not uprobes. */ if (prog->kprobe_override && !is_kprobe) return -EINVAL; if (is_tracepoint || is_syscall_tp) { int off = trace_event_get_offsets(event->tp_event); if (prog->aux->max_ctx_offset > off) return -EACCES; } return perf_event_attach_bpf_prog(event, prog, bpf_cookie); } void perf_event_free_bpf_prog(struct perf_event *event) { if (!perf_event_is_tracing(event)) { perf_event_free_bpf_handler(event); return; } perf_event_detach_bpf_prog(event); } #else static inline void perf_tp_register(void) { } static void perf_event_free_filter(struct perf_event *event) { } int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, u64 bpf_cookie) { return -ENOENT; } void perf_event_free_bpf_prog(struct perf_event *event) { } #endif /* CONFIG_EVENT_TRACING */ #ifdef CONFIG_HAVE_HW_BREAKPOINT void perf_bp_event(struct perf_event *bp, void *data) { struct perf_sample_data sample; struct pt_regs *regs = data; perf_sample_data_init(&sample, bp->attr.bp_addr, 0); if (!bp->hw.state && !perf_exclude_event(bp, regs)) perf_swevent_event(bp, 1, &sample, regs); } #endif /* * Allocate a new address filter */ static struct perf_addr_filter * perf_addr_filter_new(struct perf_event *event, struct list_head *filters) { int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); struct perf_addr_filter *filter; filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); if (!filter) return NULL; INIT_LIST_HEAD(&filter->entry); list_add_tail(&filter->entry, filters); return filter; } static void free_filters_list(struct list_head *filters) { struct perf_addr_filter *filter, *iter; list_for_each_entry_safe(filter, iter, filters, entry) { path_put(&filter->path); list_del(&filter->entry); kfree(filter); } } /* * Free existing address filters and optionally install new ones */ static void perf_addr_filters_splice(struct perf_event *event, struct list_head *head) { unsigned long flags; LIST_HEAD(list); if (!has_addr_filter(event)) return; /* don't bother with children, they don't have their own filters */ if (event->parent) return; raw_spin_lock_irqsave(&event->addr_filters.lock, flags); list_splice_init(&event->addr_filters.list, &list); if (head) list_splice(head, &event->addr_filters.list); raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); free_filters_list(&list); } /* * Scan through mm's vmas and see if one of them matches the * @filter; if so, adjust filter's address range. * Called with mm::mmap_lock down for reading. */ static void perf_addr_filter_apply(struct perf_addr_filter *filter, struct mm_struct *mm, struct perf_addr_filter_range *fr) { struct vm_area_struct *vma; VMA_ITERATOR(vmi, mm, 0); for_each_vma(vmi, vma) { if (!vma->vm_file) continue; if (perf_addr_filter_vma_adjust(filter, vma, fr)) return; } } /* * Update event's address range filters based on the * task's existing mappings, if any. */ static void perf_event_addr_filters_apply(struct perf_event *event) { struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); struct task_struct *task = READ_ONCE(event->ctx->task); struct perf_addr_filter *filter; struct mm_struct *mm = NULL; unsigned int count = 0; unsigned long flags; /* * We may observe TASK_TOMBSTONE, which means that the event tear-down * will stop on the parent's child_mutex that our caller is also holding */ if (task == TASK_TOMBSTONE) return; if (ifh->nr_file_filters) { mm = get_task_mm(task); if (!mm) goto restart; mmap_read_lock(mm); } raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { if (filter->path.dentry) { /* * Adjust base offset if the filter is associated to a * binary that needs to be mapped: */ event->addr_filter_ranges[count].start = 0; event->addr_filter_ranges[count].size = 0; perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]); } else { event->addr_filter_ranges[count].start = filter->offset; event->addr_filter_ranges[count].size = filter->size; } count++; } event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); if (ifh->nr_file_filters) { mmap_read_unlock(mm); mmput(mm); } restart: perf_event_stop(event, 1); } /* * Address range filtering: limiting the data to certain * instruction address ranges. Filters are ioctl()ed to us from * userspace as ascii strings. * * Filter string format: * * ACTION RANGE_SPEC * where ACTION is one of the * * "filter": limit the trace to this region * * "start": start tracing from this address * * "stop": stop tracing at this address/region; * RANGE_SPEC is * * for kernel addresses: <start address>[/<size>] * * for object files: <start address>[/<size>]@</path/to/object/file> * * if <size> is not specified or is zero, the range is treated as a single * address; not valid for ACTION=="filter". */ enum { IF_ACT_NONE = -1, IF_ACT_FILTER, IF_ACT_START, IF_ACT_STOP, IF_SRC_FILE, IF_SRC_KERNEL, IF_SRC_FILEADDR, IF_SRC_KERNELADDR, }; enum { IF_STATE_ACTION = 0, IF_STATE_SOURCE, IF_STATE_END, }; static const match_table_t if_tokens = { { IF_ACT_FILTER, "filter" }, { IF_ACT_START, "start" }, { IF_ACT_STOP, "stop" }, { IF_SRC_FILE, "%u/%u@%s" }, { IF_SRC_KERNEL, "%u/%u" }, { IF_SRC_FILEADDR, "%u@%s" }, { IF_SRC_KERNELADDR, "%u" }, { IF_ACT_NONE, NULL }, }; /* * Address filter string parser */ static int perf_event_parse_addr_filter(struct perf_event *event, char *fstr, struct list_head *filters) { struct perf_addr_filter *filter = NULL; char *start, *orig, *filename = NULL; substring_t args[MAX_OPT_ARGS]; int state = IF_STATE_ACTION, token; unsigned int kernel = 0; int ret = -EINVAL; orig = fstr = kstrdup(fstr, GFP_KERNEL); if (!fstr) return -ENOMEM; while ((start = strsep(&fstr, " ,\n")) != NULL) { static const enum perf_addr_filter_action_t actions[] = { [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER, [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START, [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP, }; ret = -EINVAL; if (!*start) continue; /* filter definition begins */ if (state == IF_STATE_ACTION) { filter = perf_addr_filter_new(event, filters); if (!filter) goto fail; } token = match_token(start, if_tokens, args); switch (token) { case IF_ACT_FILTER: case IF_ACT_START: case IF_ACT_STOP: if (state != IF_STATE_ACTION) goto fail; filter->action = actions[token]; state = IF_STATE_SOURCE; break; case IF_SRC_KERNELADDR: case IF_SRC_KERNEL: kernel = 1; fallthrough; case IF_SRC_FILEADDR: case IF_SRC_FILE: if (state != IF_STATE_SOURCE) goto fail; *args[0].to = 0; ret = kstrtoul(args[0].from, 0, &filter->offset); if (ret) goto fail; if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) { *args[1].to = 0; ret = kstrtoul(args[1].from, 0, &filter->size); if (ret) goto fail; } if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { int fpos = token == IF_SRC_FILE ? 2 : 1; kfree(filename); filename = match_strdup(&args[fpos]); if (!filename) { ret = -ENOMEM; goto fail; } } state = IF_STATE_END; break; default: goto fail; } /* * Filter definition is fully parsed, validate and install it. * Make sure that it doesn't contradict itself or the event's * attribute. */ if (state == IF_STATE_END) { ret = -EINVAL; /* * ACTION "filter" must have a non-zero length region * specified. */ if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER && !filter->size) goto fail; if (!kernel) { if (!filename) goto fail; /* * For now, we only support file-based filters * in per-task events; doing so for CPU-wide * events requires additional context switching * trickery, since same object code will be * mapped at different virtual addresses in * different processes. */ ret = -EOPNOTSUPP; if (!event->ctx->task) goto fail; /* look up the path and grab its inode */ ret = kern_path(filename, LOOKUP_FOLLOW, &filter->path); if (ret) goto fail; ret = -EINVAL; if (!filter->path.dentry || !S_ISREG(d_inode(filter->path.dentry) ->i_mode)) goto fail; event->addr_filters.nr_file_filters++; } /* ready to consume more filters */ kfree(filename); filename = NULL; state = IF_STATE_ACTION; filter = NULL; kernel = 0; } } if (state != IF_STATE_ACTION) goto fail; kfree(filename); kfree(orig); return 0; fail: kfree(filename); free_filters_list(filters); kfree(orig); return ret; } static int perf_event_set_addr_filter(struct perf_event *event, char *filter_str) { LIST_HEAD(filters); int ret; /* * Since this is called in perf_ioctl() path, we're already holding * ctx::mutex. */ lockdep_assert_held(&event->ctx->mutex); if (WARN_ON_ONCE(event->parent)) return -EINVAL; ret = perf_event_parse_addr_filter(event, filter_str, &filters); if (ret) goto fail_clear_files; ret = event->pmu->addr_filters_validate(&filters); if (ret) goto fail_free_filters; /* remove existing filters, if any */ perf_addr_filters_splice(event, &filters); /* install new filters */ perf_event_for_each_child(event, perf_event_addr_filters_apply); return ret; fail_free_filters: free_filters_list(&filters); fail_clear_files: event->addr_filters.nr_file_filters = 0; return ret; } static int perf_event_set_filter(struct perf_event *event, void __user *arg) { int ret = -EINVAL; char *filter_str; filter_str = strndup_user(arg, PAGE_SIZE); if (IS_ERR(filter_str)) return PTR_ERR(filter_str); #ifdef CONFIG_EVENT_TRACING if (perf_event_is_tracing(event)) { struct perf_event_context *ctx = event->ctx; /* * Beware, here be dragons!! * * the tracepoint muck will deadlock against ctx->mutex, but * the tracepoint stuff does not actually need it. So * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we * already have a reference on ctx. * * This can result in event getting moved to a different ctx, * but that does not affect the tracepoint state. */ mutex_unlock(&ctx->mutex); ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); mutex_lock(&ctx->mutex); } else #endif if (has_addr_filter(event)) ret = perf_event_set_addr_filter(event, filter_str); kfree(filter_str); return ret; } /* * hrtimer based swevent callback */ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) { enum hrtimer_restart ret = HRTIMER_RESTART; struct perf_sample_data data; struct pt_regs *regs; struct perf_event *event; u64 period; event = container_of(hrtimer, struct perf_event, hw.hrtimer); if (event->state != PERF_EVENT_STATE_ACTIVE) return HRTIMER_NORESTART; event->pmu->read(event); perf_sample_data_init(&data, 0, event->hw.last_period); regs = get_irq_regs(); if (regs && !perf_exclude_event(event, regs)) { if (!(event->attr.exclude_idle && is_idle_task(current))) if (__perf_event_overflow(event, 1, &data, regs)) ret = HRTIMER_NORESTART; } period = max_t(u64, 10000, event->hw.sample_period); hrtimer_forward_now(hrtimer, ns_to_ktime(period)); return ret; } static void perf_swevent_start_hrtimer(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; s64 period; if (!is_sampling_event(event)) return; period = local64_read(&hwc->period_left); if (period) { if (period < 0) period = 10000; local64_set(&hwc->period_left, 0); } else { period = max_t(u64, 10000, hwc->sample_period); } hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), HRTIMER_MODE_REL_PINNED_HARD); } static void perf_swevent_cancel_hrtimer(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; if (is_sampling_event(event)) { ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); local64_set(&hwc->period_left, ktime_to_ns(remaining)); hrtimer_cancel(&hwc->hrtimer); } } static void perf_swevent_init_hrtimer(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; if (!is_sampling_event(event)) return; hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); hwc->hrtimer.function = perf_swevent_hrtimer; /* * Since hrtimers have a fixed rate, we can do a static freq->period * mapping and avoid the whole period adjust feedback stuff. */ if (event->attr.freq) { long freq = event->attr.sample_freq; event->attr.sample_period = NSEC_PER_SEC / freq; hwc->sample_period = event->attr.sample_period; local64_set(&hwc->period_left, hwc->sample_period); hwc->last_period = hwc->sample_period; event->attr.freq = 0; } } /* * Software event: cpu wall time clock */ static void cpu_clock_event_update(struct perf_event *event) { s64 prev; u64 now; now = local_clock(); prev = local64_xchg(&event->hw.prev_count, now); local64_add(now - prev, &event->count); } static void cpu_clock_event_start(struct perf_event *event, int flags) { local64_set(&event->hw.prev_count, local_clock()); perf_swevent_start_hrtimer(event); } static void cpu_clock_event_stop(struct perf_event *event, int flags) { perf_swevent_cancel_hrtimer(event); cpu_clock_event_update(event); } static int cpu_clock_event_add(struct perf_event *event, int flags) { if (flags & PERF_EF_START) cpu_clock_event_start(event, flags); perf_event_update_userpage(event); return 0; } static void cpu_clock_event_del(struct perf_event *event, int flags) { cpu_clock_event_stop(event, flags); } static void cpu_clock_event_read(struct perf_event *event) { cpu_clock_event_update(event); } static int cpu_clock_event_init(struct perf_event *event) { if (event->attr.type != perf_cpu_clock.type) return -ENOENT; if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) return -ENOENT; /* * no branch sampling for software events */ if (has_branch_stack(event)) return -EOPNOTSUPP; perf_swevent_init_hrtimer(event); return 0; } static struct pmu perf_cpu_clock = { .task_ctx_nr = perf_sw_context, .capabilities = PERF_PMU_CAP_NO_NMI, .dev = PMU_NULL_DEV, .event_init = cpu_clock_event_init, .add = cpu_clock_event_add, .del = cpu_clock_event_del, .start = cpu_clock_event_start, .stop = cpu_clock_event_stop, .read = cpu_clock_event_read, }; /* * Software event: task time clock */ static void task_clock_event_update(struct perf_event *event, u64 now) { u64 prev; s64 delta; prev = local64_xchg(&event->hw.prev_count, now); delta = now - prev; local64_add(delta, &event->count); } static void task_clock_event_start(struct perf_event *event, int flags) { local64_set(&event->hw.prev_count, event->ctx->time); perf_swevent_start_hrtimer(event); } static void task_clock_event_stop(struct perf_event *event, int flags) { perf_swevent_cancel_hrtimer(event); task_clock_event_update(event, event->ctx->time); } static int task_clock_event_add(struct perf_event *event, int flags) { if (flags & PERF_EF_START) task_clock_event_start(event, flags); perf_event_update_userpage(event); return 0; } static void task_clock_event_del(struct perf_event *event, int flags) { task_clock_event_stop(event, PERF_EF_UPDATE); } static void task_clock_event_read(struct perf_event *event) { u64 now = perf_clock(); u64 delta = now - event->ctx->timestamp; u64 time = event->ctx->time + delta; task_clock_event_update(event, time); } static int task_clock_event_init(struct perf_event *event) { if (event->attr.type != perf_task_clock.type) return -ENOENT; if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) return -ENOENT; /* * no branch sampling for software events */ if (has_branch_stack(event)) return -EOPNOTSUPP; perf_swevent_init_hrtimer(event); return 0; } static struct pmu perf_task_clock = { .task_ctx_nr = perf_sw_context, .capabilities = PERF_PMU_CAP_NO_NMI, .dev = PMU_NULL_DEV, .event_init = task_clock_event_init, .add = task_clock_event_add, .del = task_clock_event_del, .start = task_clock_event_start, .stop = task_clock_event_stop, .read = task_clock_event_read, }; static void perf_pmu_nop_void(struct pmu *pmu) { } static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) { } static int perf_pmu_nop_int(struct pmu *pmu) { return 0; } static int perf_event_nop_int(struct perf_event *event, u64 value) { return 0; } static DEFINE_PER_CPU(unsigned int, nop_txn_flags); static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) { __this_cpu_write(nop_txn_flags, flags); if (flags & ~PERF_PMU_TXN_ADD) return; perf_pmu_disable(pmu); } static int perf_pmu_commit_txn(struct pmu *pmu) { unsigned int flags = __this_cpu_read(nop_txn_flags); __this_cpu_write(nop_txn_flags, 0); if (flags & ~PERF_PMU_TXN_ADD) return 0; perf_pmu_enable(pmu); return 0; } static void perf_pmu_cancel_txn(struct pmu *pmu) { unsigned int flags = __this_cpu_read(nop_txn_flags); __this_cpu_write(nop_txn_flags, 0); if (flags & ~PERF_PMU_TXN_ADD) return; perf_pmu_enable(pmu); } static int perf_event_idx_default(struct perf_event *event) { return 0; } static void free_pmu_context(struct pmu *pmu) { free_percpu(pmu->cpu_pmu_context); } /* * Let userspace know that this PMU supports address range filtering: */ static ssize_t nr_addr_filters_show(struct device *dev, struct device_attribute *attr, char *page) { struct pmu *pmu = dev_get_drvdata(dev); return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); } DEVICE_ATTR_RO(nr_addr_filters); static struct idr pmu_idr; static ssize_t type_show(struct device *dev, struct device_attribute *attr, char *page) { struct pmu *pmu = dev_get_drvdata(dev); return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type); } static DEVICE_ATTR_RO(type); static ssize_t perf_event_mux_interval_ms_show(struct device *dev, struct device_attribute *attr, char *page) { struct pmu *pmu = dev_get_drvdata(dev); return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms); } static DEFINE_MUTEX(mux_interval_mutex); static ssize_t perf_event_mux_interval_ms_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct pmu *pmu = dev_get_drvdata(dev); int timer, cpu, ret; ret = kstrtoint(buf, 0, &timer); if (ret) return ret; if (timer < 1) return -EINVAL; /* same value, noting to do */ if (timer == pmu->hrtimer_interval_ms) return count; mutex_lock(&mux_interval_mutex); pmu->hrtimer_interval_ms = timer; /* update all cpuctx for this PMU */ cpus_read_lock(); for_each_online_cpu(cpu) { struct perf_cpu_pmu_context *cpc; cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu); cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc); } cpus_read_unlock(); mutex_unlock(&mux_interval_mutex); return count; } static DEVICE_ATTR_RW(perf_event_mux_interval_ms); static struct attribute *pmu_dev_attrs[] = { &dev_attr_type.attr, &dev_attr_perf_event_mux_interval_ms.attr, &dev_attr_nr_addr_filters.attr, NULL, }; static umode_t pmu_dev_is_visible(struct kobject *kobj, struct attribute *a, int n) { struct device *dev = kobj_to_dev(kobj); struct pmu *pmu = dev_get_drvdata(dev); if (n == 2 && !pmu->nr_addr_filters) return 0; return a->mode; } static struct attribute_group pmu_dev_attr_group = { .is_visible = pmu_dev_is_visible, .attrs = pmu_dev_attrs, }; static const struct attribute_group *pmu_dev_groups[] = { &pmu_dev_attr_group, NULL, }; static int pmu_bus_running; static struct bus_type pmu_bus = { .name = "event_source", .dev_groups = pmu_dev_groups, }; static void pmu_dev_release(struct device *dev) { kfree(dev); } static int pmu_dev_alloc(struct pmu *pmu) { int ret = -ENOMEM; pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); if (!pmu->dev) goto out; pmu->dev->groups = pmu->attr_groups; device_initialize(pmu->dev); dev_set_drvdata(pmu->dev, pmu); pmu->dev->bus = &pmu_bus; pmu->dev->parent = pmu->parent; pmu->dev->release = pmu_dev_release; ret = dev_set_name(pmu->dev, "%s", pmu->name); if (ret) goto free_dev; ret = device_add(pmu->dev); if (ret) goto free_dev; if (pmu->attr_update) { ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update); if (ret) goto del_dev; } out: return ret; del_dev: device_del(pmu->dev); free_dev: put_device(pmu->dev); goto out; } static struct lock_class_key cpuctx_mutex; static struct lock_class_key cpuctx_lock; int perf_pmu_register(struct pmu *pmu, const char *name, int type) { int cpu, ret, max = PERF_TYPE_MAX; mutex_lock(&pmus_lock); ret = -ENOMEM; pmu->pmu_disable_count = alloc_percpu(int); if (!pmu->pmu_disable_count) goto unlock; pmu->type = -1; if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) { ret = -EINVAL; goto free_pdc; } pmu->name = name; if (type >= 0) max = type; ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL); if (ret < 0) goto free_pdc; WARN_ON(type >= 0 && ret != type); type = ret; pmu->type = type; if (pmu_bus_running && !pmu->dev) { ret = pmu_dev_alloc(pmu); if (ret) goto free_idr; } ret = -ENOMEM; pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context); if (!pmu->cpu_pmu_context) goto free_dev; for_each_possible_cpu(cpu) { struct perf_cpu_pmu_context *cpc; cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu); __perf_init_event_pmu_context(&cpc->epc, pmu); __perf_mux_hrtimer_init(cpc, cpu); } if (!pmu->start_txn) { if (pmu->pmu_enable) { /* * If we have pmu_enable/pmu_disable calls, install * transaction stubs that use that to try and batch * hardware accesses. */ pmu->start_txn = perf_pmu_start_txn; pmu->commit_txn = perf_pmu_commit_txn; pmu->cancel_txn = perf_pmu_cancel_txn; } else { pmu->start_txn = perf_pmu_nop_txn; pmu->commit_txn = perf_pmu_nop_int; pmu->cancel_txn = perf_pmu_nop_void; } } if (!pmu->pmu_enable) { pmu->pmu_enable = perf_pmu_nop_void; pmu->pmu_disable = perf_pmu_nop_void; } if (!pmu->check_period) pmu->check_period = perf_event_nop_int; if (!pmu->event_idx) pmu->event_idx = perf_event_idx_default; list_add_rcu(&pmu->entry, &pmus); atomic_set(&pmu->exclusive_cnt, 0); ret = 0; unlock: mutex_unlock(&pmus_lock); return ret; free_dev: if (pmu->dev && pmu->dev != PMU_NULL_DEV) { device_del(pmu->dev); put_device(pmu->dev); } free_idr: idr_remove(&pmu_idr, pmu->type); free_pdc: free_percpu(pmu->pmu_disable_count); goto unlock; } EXPORT_SYMBOL_GPL(perf_pmu_register); void perf_pmu_unregister(struct pmu *pmu) { mutex_lock(&pmus_lock); list_del_rcu(&pmu->entry); /* * We dereference the pmu list under both SRCU and regular RCU, so * synchronize against both of those. */ synchronize_srcu(&pmus_srcu); synchronize_rcu(); free_percpu(pmu->pmu_disable_count); idr_remove(&pmu_idr, pmu->type); if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) { if (pmu->nr_addr_filters) device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); device_del(pmu->dev); put_device(pmu->dev); } free_pmu_context(pmu); mutex_unlock(&pmus_lock); } EXPORT_SYMBOL_GPL(perf_pmu_unregister); static inline bool has_extended_regs(struct perf_event *event) { return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) || (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); } static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) { struct perf_event_context *ctx = NULL; int ret; if (!try_module_get(pmu->module)) return -ENODEV; /* * A number of pmu->event_init() methods iterate the sibling_list to, * for example, validate if the group fits on the PMU. Therefore, * if this is a sibling event, acquire the ctx->mutex to protect * the sibling_list. */ if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) { /* * This ctx->mutex can nest when we're called through * inheritance. See the perf_event_ctx_lock_nested() comment. */ ctx = perf_event_ctx_lock_nested(event->group_leader, SINGLE_DEPTH_NESTING); BUG_ON(!ctx); } event->pmu = pmu; ret = pmu->event_init(event); if (ctx) perf_event_ctx_unlock(event->group_leader, ctx); if (!ret) { if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) && has_extended_regs(event)) ret = -EOPNOTSUPP; if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE && event_has_any_exclude_flag(event)) ret = -EINVAL; if (ret && event->destroy) event->destroy(event); } if (ret) module_put(pmu->module); return ret; } static struct pmu *perf_init_event(struct perf_event *event) { bool extended_type = false; int idx, type, ret; struct pmu *pmu; idx = srcu_read_lock(&pmus_srcu); /* * Save original type before calling pmu->event_init() since certain * pmus overwrites event->attr.type to forward event to another pmu. */ event->orig_type = event->attr.type; /* Try parent's PMU first: */ if (event->parent && event->parent->pmu) { pmu = event->parent->pmu; ret = perf_try_init_event(pmu, event); if (!ret) goto unlock; } /* * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE * are often aliases for PERF_TYPE_RAW. */ type = event->attr.type; if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) { type = event->attr.config >> PERF_PMU_TYPE_SHIFT; if (!type) { type = PERF_TYPE_RAW; } else { extended_type = true; event->attr.config &= PERF_HW_EVENT_MASK; } } again: rcu_read_lock(); pmu = idr_find(&pmu_idr, type); rcu_read_unlock(); if (pmu) { if (event->attr.type != type && type != PERF_TYPE_RAW && !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)) goto fail; ret = perf_try_init_event(pmu, event); if (ret == -ENOENT && event->attr.type != type && !extended_type) { type = event->attr.type; goto again; } if (ret) pmu = ERR_PTR(ret); goto unlock; } list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) { ret = perf_try_init_event(pmu, event); if (!ret) goto unlock; if (ret != -ENOENT) { pmu = ERR_PTR(ret); goto unlock; } } fail: pmu = ERR_PTR(-ENOENT); unlock: srcu_read_unlock(&pmus_srcu, idx); return pmu; } static void attach_sb_event(struct perf_event *event) { struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); raw_spin_lock(&pel->lock); list_add_rcu(&event->sb_list, &pel->list); raw_spin_unlock(&pel->lock); } /* * We keep a list of all !task (and therefore per-cpu) events * that need to receive side-band records. * * This avoids having to scan all the various PMU per-cpu contexts * looking for them. */ static void account_pmu_sb_event(struct perf_event *event) { if (is_sb_event(event)) attach_sb_event(event); } /* Freq events need the tick to stay alive (see perf_event_task_tick). */ static void account_freq_event_nohz(void) { #ifdef CONFIG_NO_HZ_FULL /* Lock so we don't race with concurrent unaccount */ spin_lock(&nr_freq_lock); if (atomic_inc_return(&nr_freq_events) == 1) tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); spin_unlock(&nr_freq_lock); #endif } static void account_freq_event(void) { if (tick_nohz_full_enabled()) account_freq_event_nohz(); else atomic_inc(&nr_freq_events); } static void account_event(struct perf_event *event) { bool inc = false; if (event->parent) return; if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) inc = true; if (event->attr.mmap || event->attr.mmap_data) atomic_inc(&nr_mmap_events); if (event->attr.build_id) atomic_inc(&nr_build_id_events); if (event->attr.comm) atomic_inc(&nr_comm_events); if (event->attr.namespaces) atomic_inc(&nr_namespaces_events); if (event->attr.cgroup) atomic_inc(&nr_cgroup_events); if (event->attr.task) atomic_inc(&nr_task_events); if (event->attr.freq) account_freq_event(); if (event->attr.context_switch) { atomic_inc(&nr_switch_events); inc = true; } if (has_branch_stack(event)) inc = true; if (is_cgroup_event(event)) inc = true; if (event->attr.ksymbol) atomic_inc(&nr_ksymbol_events); if (event->attr.bpf_event) atomic_inc(&nr_bpf_events); if (event->attr.text_poke) atomic_inc(&nr_text_poke_events); if (inc) { /* * We need the mutex here because static_branch_enable() * must complete *before* the perf_sched_count increment * becomes visible. */ if (atomic_inc_not_zero(&perf_sched_count)) goto enabled; mutex_lock(&perf_sched_mutex); if (!atomic_read(&perf_sched_count)) { static_branch_enable(&perf_sched_events); /* * Guarantee that all CPUs observe they key change and * call the perf scheduling hooks before proceeding to * install events that need them. */ synchronize_rcu(); } /* * Now that we have waited for the sync_sched(), allow further * increments to by-pass the mutex. */ atomic_inc(&perf_sched_count); mutex_unlock(&perf_sched_mutex); } enabled: account_pmu_sb_event(event); } /* * Allocate and initialize an event structure */ static struct perf_event * perf_event_alloc(struct perf_event_attr *attr, int cpu, struct task_struct *task, struct perf_event *group_leader, struct perf_event *parent_event, perf_overflow_handler_t overflow_handler, void *context, int cgroup_fd) { struct pmu *pmu; struct perf_event *event; struct hw_perf_event *hwc; long err = -EINVAL; int node; if ((unsigned)cpu >= nr_cpu_ids) { if (!task || cpu != -1) return ERR_PTR(-EINVAL); } if (attr->sigtrap && !task) { /* Requires a task: avoid signalling random tasks. */ return ERR_PTR(-EINVAL); } node = (cpu >= 0) ? cpu_to_node(cpu) : -1; event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, node); if (!event) return ERR_PTR(-ENOMEM); /* * Single events are their own group leaders, with an * empty sibling list: */ if (!group_leader) group_leader = event; mutex_init(&event->child_mutex); INIT_LIST_HEAD(&event->child_list); INIT_LIST_HEAD(&event->event_entry); INIT_LIST_HEAD(&event->sibling_list); INIT_LIST_HEAD(&event->active_list); init_event_group(event); INIT_LIST_HEAD(&event->rb_entry); INIT_LIST_HEAD(&event->active_entry); INIT_LIST_HEAD(&event->addr_filters.list); INIT_HLIST_NODE(&event->hlist_entry); init_waitqueue_head(&event->waitq); init_irq_work(&event->pending_irq, perf_pending_irq); event->pending_disable_irq = IRQ_WORK_INIT_HARD(perf_pending_disable); init_task_work(&event->pending_task, perf_pending_task); rcuwait_init(&event->pending_work_wait); mutex_init(&event->mmap_mutex); raw_spin_lock_init(&event->addr_filters.lock); atomic_long_set(&event->refcount, 1); event->cpu = cpu; event->attr = *attr; event->group_leader = group_leader; event->pmu = NULL; event->oncpu = -1; event->parent = parent_event; event->ns = get_pid_ns(task_active_pid_ns(current)); event->id = atomic64_inc_return(&perf_event_id); event->state = PERF_EVENT_STATE_INACTIVE; if (parent_event) event->event_caps = parent_event->event_caps; if (task) { event->attach_state = PERF_ATTACH_TASK; /* * XXX pmu::event_init needs to know what task to account to * and we cannot use the ctx information because we need the * pmu before we get a ctx. */ event->hw.target = get_task_struct(task); } event->clock = &local_clock; if (parent_event) event->clock = parent_event->clock; if (!overflow_handler && parent_event) { overflow_handler = parent_event->overflow_handler; context = parent_event->overflow_handler_context; #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) if (parent_event->prog) { struct bpf_prog *prog = parent_event->prog; bpf_prog_inc(prog); event->prog = prog; } #endif } if (overflow_handler) { event->overflow_handler = overflow_handler; event->overflow_handler_context = context; } else if (is_write_backward(event)){ event->overflow_handler = perf_event_output_backward; event->overflow_handler_context = NULL; } else { event->overflow_handler = perf_event_output_forward; event->overflow_handler_context = NULL; } perf_event__state_init(event); pmu = NULL; hwc = &event->hw; hwc->sample_period = attr->sample_period; if (attr->freq && attr->sample_freq) hwc->sample_period = 1; hwc->last_period = hwc->sample_period; local64_set(&hwc->period_left, hwc->sample_period); /* * We currently do not support PERF_SAMPLE_READ on inherited events. * See perf_output_read(). */ if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) goto err_ns; if (!has_branch_stack(event)) event->attr.branch_sample_type = 0; pmu = perf_init_event(event); if (IS_ERR(pmu)) { err = PTR_ERR(pmu); goto err_ns; } /* * Disallow uncore-task events. Similarly, disallow uncore-cgroup * events (they don't make sense as the cgroup will be different * on other CPUs in the uncore mask). */ if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) { err = -EINVAL; goto err_pmu; } if (event->attr.aux_output && !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { err = -EOPNOTSUPP; goto err_pmu; } if (cgroup_fd != -1) { err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); if (err) goto err_pmu; } err = exclusive_event_init(event); if (err) goto err_pmu; if (has_addr_filter(event)) { event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters, sizeof(struct perf_addr_filter_range), GFP_KERNEL); if (!event->addr_filter_ranges) { err = -ENOMEM; goto err_per_task; } /* * Clone the parent's vma offsets: they are valid until exec() * even if the mm is not shared with the parent. */ if (event->parent) { struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); raw_spin_lock_irq(&ifh->lock); memcpy(event->addr_filter_ranges, event->parent->addr_filter_ranges, pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range)); raw_spin_unlock_irq(&ifh->lock); } /* force hw sync on the address filters */ event->addr_filters_gen = 1; } if (!event->parent) { if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { err = get_callchain_buffers(attr->sample_max_stack); if (err) goto err_addr_filters; } } err = security_perf_event_alloc(event); if (err) goto err_callchain_buffer; /* symmetric to unaccount_event() in _free_event() */ account_event(event); return event; err_callchain_buffer: if (!event->parent) { if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) put_callchain_buffers(); } err_addr_filters: kfree(event->addr_filter_ranges); err_per_task: exclusive_event_destroy(event); err_pmu: if (is_cgroup_event(event)) perf_detach_cgroup(event); if (event->destroy) event->destroy(event); module_put(pmu->module); err_ns: if (event->hw.target) put_task_struct(event->hw.target); call_rcu(&event->rcu_head, free_event_rcu); return ERR_PTR(err); } static int perf_copy_attr(struct perf_event_attr __user *uattr, struct perf_event_attr *attr) { u32 size; int ret; /* Zero the full structure, so that a short copy will be nice. */ memset(attr, 0, sizeof(*attr)); ret = get_user(size, &uattr->size); if (ret) return ret; /* ABI compatibility quirk: */ if (!size) size = PERF_ATTR_SIZE_VER0; if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE) goto err_size; ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size); if (ret) { if (ret == -E2BIG) goto err_size; return ret; } attr->size = size; if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3) return -EINVAL; if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) return -EINVAL; if (attr->read_format & ~(PERF_FORMAT_MAX-1)) return -EINVAL; if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { u64 mask = attr->branch_sample_type; /* only using defined bits */ if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) return -EINVAL; /* at least one branch bit must be set */ if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) return -EINVAL; /* propagate priv level, when not set for branch */ if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { /* exclude_kernel checked on syscall entry */ if (!attr->exclude_kernel) mask |= PERF_SAMPLE_BRANCH_KERNEL; if (!attr->exclude_user) mask |= PERF_SAMPLE_BRANCH_USER; if (!attr->exclude_hv) mask |= PERF_SAMPLE_BRANCH_HV; /* * adjust user setting (for HW filter setup) */ attr->branch_sample_type = mask; } /* privileged levels capture (kernel, hv): check permissions */ if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) { ret = perf_allow_kernel(attr); if (ret) return ret; } } if (attr->sample_type & PERF_SAMPLE_REGS_USER) { ret = perf_reg_validate(attr->sample_regs_user); if (ret) return ret; } if (attr->sample_type & PERF_SAMPLE_STACK_USER) { if (!arch_perf_have_user_stack_dump()) return -ENOSYS; /* * We have __u32 type for the size, but so far * we can only use __u16 as maximum due to the * __u16 sample size limit. */ if (attr->sample_stack_user >= USHRT_MAX) return -EINVAL; else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) return -EINVAL; } if (!attr->sample_max_stack) attr->sample_max_stack = sysctl_perf_event_max_stack; if (attr->sample_type & PERF_SAMPLE_REGS_INTR) ret = perf_reg_validate(attr->sample_regs_intr); #ifndef CONFIG_CGROUP_PERF if (attr->sample_type & PERF_SAMPLE_CGROUP) return -EINVAL; #endif if ((attr->sample_type & PERF_SAMPLE_WEIGHT) && (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT)) return -EINVAL; if (!attr->inherit && attr->inherit_thread) return -EINVAL; if (attr->remove_on_exec && attr->enable_on_exec) return -EINVAL; if (attr->sigtrap && !attr->remove_on_exec) return -EINVAL; out: return ret; err_size: put_user(sizeof(*attr), &uattr->size); ret = -E2BIG; goto out; } static void mutex_lock_double(struct mutex *a, struct mutex *b) { if (b < a) swap(a, b); mutex_lock(a); mutex_lock_nested(b, SINGLE_DEPTH_NESTING); } static int perf_event_set_output(struct perf_event *event, struct perf_event *output_event) { struct perf_buffer *rb = NULL; int ret = -EINVAL; if (!output_event) { mutex_lock(&event->mmap_mutex); goto set; } /* don't allow circular references */ if (event == output_event) goto out; /* * Don't allow cross-cpu buffers */ if (output_event->cpu != event->cpu) goto out; /* * If its not a per-cpu rb, it must be the same task. */ if (output_event->cpu == -1 && output_event->hw.target != event->hw.target) goto out; /* * Mixing clocks in the same buffer is trouble you don't need. */ if (output_event->clock != event->clock) goto out; /* * Either writing ring buffer from beginning or from end. * Mixing is not allowed. */ if (is_write_backward(output_event) != is_write_backward(event)) goto out; /* * If both events generate aux data, they must be on the same PMU */ if (has_aux(event) && has_aux(output_event) && event->pmu != output_event->pmu) goto out; /* * Hold both mmap_mutex to serialize against perf_mmap_close(). Since * output_event is already on rb->event_list, and the list iteration * restarts after every removal, it is guaranteed this new event is * observed *OR* if output_event is already removed, it's guaranteed we * observe !rb->mmap_count. */ mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex); set: /* Can't redirect output if we've got an active mmap() */ if (atomic_read(&event->mmap_count)) goto unlock; if (output_event) { /* get the rb we want to redirect to */ rb = ring_buffer_get(output_event); if (!rb) goto unlock; /* did we race against perf_mmap_close() */ if (!atomic_read(&rb->mmap_count)) { ring_buffer_put(rb); goto unlock; } } ring_buffer_attach(event, rb); ret = 0; unlock: mutex_unlock(&event->mmap_mutex); if (output_event) mutex_unlock(&output_event->mmap_mutex); out: return ret; } static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) { bool nmi_safe = false; switch (clk_id) { case CLOCK_MONOTONIC: event->clock = &ktime_get_mono_fast_ns; nmi_safe = true; break; case CLOCK_MONOTONIC_RAW: event->clock = &ktime_get_raw_fast_ns; nmi_safe = true; break; case CLOCK_REALTIME: event->clock = &ktime_get_real_ns; break; case CLOCK_BOOTTIME: event->clock = &ktime_get_boottime_ns; break; case CLOCK_TAI: event->clock = &ktime_get_clocktai_ns; break; default: return -EINVAL; } if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) return -EINVAL; return 0; } static bool perf_check_permission(struct perf_event_attr *attr, struct task_struct *task) { unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS; bool is_capable = perfmon_capable(); if (attr->sigtrap) { /* * perf_event_attr::sigtrap sends signals to the other task. * Require the current task to also have CAP_KILL. */ rcu_read_lock(); is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL); rcu_read_unlock(); /* * If the required capabilities aren't available, checks for * ptrace permissions: upgrade to ATTACH, since sending signals * can effectively change the target task. */ ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS; } /* * Preserve ptrace permission check for backwards compatibility. The * ptrace check also includes checks that the current task and other * task have matching uids, and is therefore not done here explicitly. */ return is_capable || ptrace_may_access(task, ptrace_mode); } /** * sys_perf_event_open - open a performance event, associate it to a task/cpu * * @attr_uptr: event_id type attributes for monitoring/sampling * @pid: target pid * @cpu: target cpu * @group_fd: group leader event fd * @flags: perf event open flags */ SYSCALL_DEFINE5(perf_event_open, struct perf_event_attr __user *, attr_uptr, pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) { struct perf_event *group_leader = NULL, *output_event = NULL; struct perf_event_pmu_context *pmu_ctx; struct perf_event *event, *sibling; struct perf_event_attr attr; struct perf_event_context *ctx; struct file *event_file = NULL; struct fd group = {NULL, 0}; struct task_struct *task = NULL; struct pmu *pmu; int event_fd; int move_group = 0; int err; int f_flags = O_RDWR; int cgroup_fd = -1; /* for future expandability... */ if (flags & ~PERF_FLAG_ALL) return -EINVAL; err = perf_copy_attr(attr_uptr, &attr); if (err) return err; /* Do we allow access to perf_event_open(2) ? */ err = security_perf_event_open(&attr, PERF_SECURITY_OPEN); if (err) return err; if (!attr.exclude_kernel) { err = perf_allow_kernel(&attr); if (err) return err; } if (attr.namespaces) { if (!perfmon_capable()) return -EACCES; } if (attr.freq) { if (attr.sample_freq > sysctl_perf_event_sample_rate) return -EINVAL; } else { if (attr.sample_period & (1ULL << 63)) return -EINVAL; } /* Only privileged users can get physical addresses */ if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) { err = perf_allow_kernel(&attr); if (err) return err; } /* REGS_INTR can leak data, lockdown must prevent this */ if (attr.sample_type & PERF_SAMPLE_REGS_INTR) { err = security_locked_down(LOCKDOWN_PERF); if (err) return err; } /* * In cgroup mode, the pid argument is used to pass the fd * opened to the cgroup directory in cgroupfs. The cpu argument * designates the cpu on which to monitor threads from that * cgroup. */ if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) return -EINVAL; if (flags & PERF_FLAG_FD_CLOEXEC) f_flags |= O_CLOEXEC; event_fd = get_unused_fd_flags(f_flags); if (event_fd < 0) return event_fd; if (group_fd != -1) { err = perf_fget_light(group_fd, &group); if (err) goto err_fd; group_leader = group.file->private_data; if (flags & PERF_FLAG_FD_OUTPUT) output_event = group_leader; if (flags & PERF_FLAG_FD_NO_GROUP) group_leader = NULL; } if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { task = find_lively_task_by_vpid(pid); if (IS_ERR(task)) { err = PTR_ERR(task); goto err_group_fd; } } if (task && group_leader && group_leader->attr.inherit != attr.inherit) { err = -EINVAL; goto err_task; } if (flags & PERF_FLAG_PID_CGROUP) cgroup_fd = pid; event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, NULL, NULL, cgroup_fd); if (IS_ERR(event)) { err = PTR_ERR(event); goto err_task; } if (is_sampling_event(event)) { if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { err = -EOPNOTSUPP; goto err_alloc; } } /* * Special case software events and allow them to be part of * any hardware group. */ pmu = event->pmu; if (attr.use_clockid) { err = perf_event_set_clock(event, attr.clockid); if (err) goto err_alloc; } if (pmu->task_ctx_nr == perf_sw_context) event->event_caps |= PERF_EV_CAP_SOFTWARE; if (task) { err = down_read_interruptible(&task->signal->exec_update_lock); if (err) goto err_alloc; /* * We must hold exec_update_lock across this and any potential * perf_install_in_context() call for this new event to * serialize against exec() altering our credentials (and the * perf_event_exit_task() that could imply). */ err = -EACCES; if (!perf_check_permission(&attr, task)) goto err_cred; } /* * Get the target context (task or percpu): */ ctx = find_get_context(task, event); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); goto err_cred; } mutex_lock(&ctx->mutex); if (ctx->task == TASK_TOMBSTONE) { err = -ESRCH; goto err_locked; } if (!task) { /* * Check if the @cpu we're creating an event for is online. * * We use the perf_cpu_context::ctx::mutex to serialize against * the hotplug notifiers. See perf_event_{init,exit}_cpu(). */ struct perf_cpu_context *cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu); if (!cpuctx->online) { err = -ENODEV; goto err_locked; } } if (group_leader) { err = -EINVAL; /* * Do not allow a recursive hierarchy (this new sibling * becoming part of another group-sibling): */ if (group_leader->group_leader != group_leader) goto err_locked; /* All events in a group should have the same clock */ if (group_leader->clock != event->clock) goto err_locked; /* * Make sure we're both events for the same CPU; * grouping events for different CPUs is broken; since * you can never concurrently schedule them anyhow. */ if (group_leader->cpu != event->cpu) goto err_locked; /* * Make sure we're both on the same context; either task or cpu. */ if (group_leader->ctx != ctx) goto err_locked; /* * Only a group leader can be exclusive or pinned */ if (attr.exclusive || attr.pinned) goto err_locked; if (is_software_event(event) && !in_software_context(group_leader)) { /* * If the event is a sw event, but the group_leader * is on hw context. * * Allow the addition of software events to hw * groups, this is safe because software events * never fail to schedule. * * Note the comment that goes with struct * perf_event_pmu_context. */ pmu = group_leader->pmu_ctx->pmu; } else if (!is_software_event(event)) { if (is_software_event(group_leader) && (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { /* * In case the group is a pure software group, and we * try to add a hardware event, move the whole group to * the hardware context. */ move_group = 1; } /* Don't allow group of multiple hw events from different pmus */ if (!in_software_context(group_leader) && group_leader->pmu_ctx->pmu != pmu) goto err_locked; } } /* * Now that we're certain of the pmu; find the pmu_ctx. */ pmu_ctx = find_get_pmu_context(pmu, ctx, event); if (IS_ERR(pmu_ctx)) { err = PTR_ERR(pmu_ctx); goto err_locked; } event->pmu_ctx = pmu_ctx; if (output_event) { err = perf_event_set_output(event, output_event); if (err) goto err_context; } if (!perf_event_validate_size(event)) { err = -E2BIG; goto err_context; } if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) { err = -EINVAL; goto err_context; } /* * Must be under the same ctx::mutex as perf_install_in_context(), * because we need to serialize with concurrent event creation. */ if (!exclusive_event_installable(event, ctx)) { err = -EBUSY; goto err_context; } WARN_ON_ONCE(ctx->parent_ctx); event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, f_flags); if (IS_ERR(event_file)) { err = PTR_ERR(event_file); event_file = NULL; goto err_context; } /* * This is the point on no return; we cannot fail hereafter. This is * where we start modifying current state. */ if (move_group) { perf_remove_from_context(group_leader, 0); put_pmu_ctx(group_leader->pmu_ctx); for_each_sibling_event(sibling, group_leader) { perf_remove_from_context(sibling, 0); put_pmu_ctx(sibling->pmu_ctx); } /* * Install the group siblings before the group leader. * * Because a group leader will try and install the entire group * (through the sibling list, which is still in-tact), we can * end up with siblings installed in the wrong context. * * By installing siblings first we NO-OP because they're not * reachable through the group lists. */ for_each_sibling_event(sibling, group_leader) { sibling->pmu_ctx = pmu_ctx; get_pmu_ctx(pmu_ctx); perf_event__state_init(sibling); perf_install_in_context(ctx, sibling, sibling->cpu); } /* * Removing from the context ends up with disabled * event. What we want here is event in the initial * startup state, ready to be add into new context. */ group_leader->pmu_ctx = pmu_ctx; get_pmu_ctx(pmu_ctx); perf_event__state_init(group_leader); perf_install_in_context(ctx, group_leader, group_leader->cpu); } /* * Precalculate sample_data sizes; do while holding ctx::mutex such * that we're serialized against further additions and before * perf_install_in_context() which is the point the event is active and * can use these values. */ perf_event__header_size(event); perf_event__id_header_size(event); event->owner = current; perf_install_in_context(ctx, event, event->cpu); perf_unpin_context(ctx); mutex_unlock(&ctx->mutex); if (task) { up_read(&task->signal->exec_update_lock); put_task_struct(task); } mutex_lock(¤t->perf_event_mutex); list_add_tail(&event->owner_entry, ¤t->perf_event_list); mutex_unlock(¤t->perf_event_mutex); /* * Drop the reference on the group_event after placing the * new event on the sibling_list. This ensures destruction * of the group leader will find the pointer to itself in * perf_group_detach(). */ fdput(group); fd_install(event_fd, event_file); return event_fd; err_context: put_pmu_ctx(event->pmu_ctx); event->pmu_ctx = NULL; /* _free_event() */ err_locked: mutex_unlock(&ctx->mutex); perf_unpin_context(ctx); put_ctx(ctx); err_cred: if (task) up_read(&task->signal->exec_update_lock); err_alloc: free_event(event); err_task: if (task) put_task_struct(task); err_group_fd: fdput(group); err_fd: put_unused_fd(event_fd); return err; } /** * perf_event_create_kernel_counter * * @attr: attributes of the counter to create * @cpu: cpu in which the counter is bound * @task: task to profile (NULL for percpu) * @overflow_handler: callback to trigger when we hit the event * @context: context data could be used in overflow_handler callback */ struct perf_event * perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, struct task_struct *task, perf_overflow_handler_t overflow_handler, void *context) { struct perf_event_pmu_context *pmu_ctx; struct perf_event_context *ctx; struct perf_event *event; struct pmu *pmu; int err; /* * Grouping is not supported for kernel events, neither is 'AUX', * make sure the caller's intentions are adjusted. */ if (attr->aux_output) return ERR_PTR(-EINVAL); event = perf_event_alloc(attr, cpu, task, NULL, NULL, overflow_handler, context, -1); if (IS_ERR(event)) { err = PTR_ERR(event); goto err; } /* Mark owner so we could distinguish it from user events. */ event->owner = TASK_TOMBSTONE; pmu = event->pmu; if (pmu->task_ctx_nr == perf_sw_context) event->event_caps |= PERF_EV_CAP_SOFTWARE; /* * Get the target context (task or percpu): */ ctx = find_get_context(task, event); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); goto err_alloc; } WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); if (ctx->task == TASK_TOMBSTONE) { err = -ESRCH; goto err_unlock; } pmu_ctx = find_get_pmu_context(pmu, ctx, event); if (IS_ERR(pmu_ctx)) { err = PTR_ERR(pmu_ctx); goto err_unlock; } event->pmu_ctx = pmu_ctx; if (!task) { /* * Check if the @cpu we're creating an event for is online. * * We use the perf_cpu_context::ctx::mutex to serialize against * the hotplug notifiers. See perf_event_{init,exit}_cpu(). */ struct perf_cpu_context *cpuctx = container_of(ctx, struct perf_cpu_context, ctx); if (!cpuctx->online) { err = -ENODEV; goto err_pmu_ctx; } } if (!exclusive_event_installable(event, ctx)) { err = -EBUSY; goto err_pmu_ctx; } perf_install_in_context(ctx, event, event->cpu); perf_unpin_context(ctx); mutex_unlock(&ctx->mutex); return event; err_pmu_ctx: put_pmu_ctx(pmu_ctx); event->pmu_ctx = NULL; /* _free_event() */ err_unlock: mutex_unlock(&ctx->mutex); perf_unpin_context(ctx); put_ctx(ctx); err_alloc: free_event(event); err: return ERR_PTR(err); } EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); static void __perf_pmu_remove(struct perf_event_context *ctx, int cpu, struct pmu *pmu, struct perf_event_groups *groups, struct list_head *events) { struct perf_event *event, *sibling; perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) { perf_remove_from_context(event, 0); put_pmu_ctx(event->pmu_ctx); list_add(&event->migrate_entry, events); for_each_sibling_event(sibling, event) { perf_remove_from_context(sibling, 0); put_pmu_ctx(sibling->pmu_ctx); list_add(&sibling->migrate_entry, events); } } } static void __perf_pmu_install_event(struct pmu *pmu, struct perf_event_context *ctx, int cpu, struct perf_event *event) { struct perf_event_pmu_context *epc; struct perf_event_context *old_ctx = event->ctx; get_ctx(ctx); /* normally find_get_context() */ event->cpu = cpu; epc = find_get_pmu_context(pmu, ctx, event); event->pmu_ctx = epc; if (event->state >= PERF_EVENT_STATE_OFF) event->state = PERF_EVENT_STATE_INACTIVE; perf_install_in_context(ctx, event, cpu); /* * Now that event->ctx is updated and visible, put the old ctx. */ put_ctx(old_ctx); } static void __perf_pmu_install(struct perf_event_context *ctx, int cpu, struct pmu *pmu, struct list_head *events) { struct perf_event *event, *tmp; /* * Re-instate events in 2 passes. * * Skip over group leaders and only install siblings on this first * pass, siblings will not get enabled without a leader, however a * leader will enable its siblings, even if those are still on the old * context. */ list_for_each_entry_safe(event, tmp, events, migrate_entry) { if (event->group_leader == event) continue; list_del(&event->migrate_entry); __perf_pmu_install_event(pmu, ctx, cpu, event); } /* * Once all the siblings are setup properly, install the group leaders * to make it go. */ list_for_each_entry_safe(event, tmp, events, migrate_entry) { list_del(&event->migrate_entry); __perf_pmu_install_event(pmu, ctx, cpu, event); } } void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) { struct perf_event_context *src_ctx, *dst_ctx; LIST_HEAD(events); /* * Since per-cpu context is persistent, no need to grab an extra * reference. */ src_ctx = &per_cpu_ptr(&perf_cpu_context, src_cpu)->ctx; dst_ctx = &per_cpu_ptr(&perf_cpu_context, dst_cpu)->ctx; /* * See perf_event_ctx_lock() for comments on the details * of swizzling perf_event::ctx. */ mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->pinned_groups, &events); __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->flexible_groups, &events); if (!list_empty(&events)) { /* * Wait for the events to quiesce before re-instating them. */ synchronize_rcu(); __perf_pmu_install(dst_ctx, dst_cpu, pmu, &events); } mutex_unlock(&dst_ctx->mutex); mutex_unlock(&src_ctx->mutex); } EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); static void sync_child_event(struct perf_event *child_event) { struct perf_event *parent_event = child_event->parent; u64 child_val; if (child_event->attr.inherit_stat) { struct task_struct *task = child_event->ctx->task; if (task && task != TASK_TOMBSTONE) perf_event_read_event(child_event, task); } child_val = perf_event_count(child_event); /* * Add back the child's count to the parent's count: */ atomic64_add(child_val, &parent_event->child_count); atomic64_add(child_event->total_time_enabled, &parent_event->child_total_time_enabled); atomic64_add(child_event->total_time_running, &parent_event->child_total_time_running); } static void perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event *parent_event = event->parent; unsigned long detach_flags = 0; if (parent_event) { /* * Do not destroy the 'original' grouping; because of the * context switch optimization the original events could've * ended up in a random child task. * * If we were to destroy the original group, all group related * operations would cease to function properly after this * random child dies. * * Do destroy all inherited groups, we don't care about those * and being thorough is better. */ detach_flags = DETACH_GROUP | DETACH_CHILD; mutex_lock(&parent_event->child_mutex); } perf_remove_from_context(event, detach_flags); raw_spin_lock_irq(&ctx->lock); if (event->state > PERF_EVENT_STATE_EXIT) perf_event_set_state(event, PERF_EVENT_STATE_EXIT); raw_spin_unlock_irq(&ctx->lock); /* * Child events can be freed. */ if (parent_event) { mutex_unlock(&parent_event->child_mutex); /* * Kick perf_poll() for is_event_hup(); */ perf_event_wakeup(parent_event); free_event(event); put_event(parent_event); return; } /* * Parent events are governed by their filedesc, retain them. */ perf_event_wakeup(event); } static void perf_event_exit_task_context(struct task_struct *child) { struct perf_event_context *child_ctx, *clone_ctx = NULL; struct perf_event *child_event, *next; WARN_ON_ONCE(child != current); child_ctx = perf_pin_task_context(child); if (!child_ctx) return; /* * In order to reduce the amount of tricky in ctx tear-down, we hold * ctx::mutex over the entire thing. This serializes against almost * everything that wants to access the ctx. * * The exception is sys_perf_event_open() / * perf_event_create_kernel_count() which does find_get_context() * without ctx::mutex (it cannot because of the move_group double mutex * lock thing). See the comments in perf_install_in_context(). */ mutex_lock(&child_ctx->mutex); /* * In a single ctx::lock section, de-schedule the events and detach the * context from the task such that we cannot ever get it scheduled back * in. */ raw_spin_lock_irq(&child_ctx->lock); task_ctx_sched_out(child_ctx, EVENT_ALL); /* * Now that the context is inactive, destroy the task <-> ctx relation * and mark the context dead. */ RCU_INIT_POINTER(child->perf_event_ctxp, NULL); put_ctx(child_ctx); /* cannot be last */ WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); put_task_struct(current); /* cannot be last */ clone_ctx = unclone_ctx(child_ctx); raw_spin_unlock_irq(&child_ctx->lock); if (clone_ctx) put_ctx(clone_ctx); /* * Report the task dead after unscheduling the events so that we * won't get any samples after PERF_RECORD_EXIT. We can however still * get a few PERF_RECORD_READ events. */ perf_event_task(child, child_ctx, 0); list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) perf_event_exit_event(child_event, child_ctx); mutex_unlock(&child_ctx->mutex); put_ctx(child_ctx); } /* * When a child task exits, feed back event values to parent events. * * Can be called with exec_update_lock held when called from * setup_new_exec(). */ void perf_event_exit_task(struct task_struct *child) { struct perf_event *event, *tmp; mutex_lock(&child->perf_event_mutex); list_for_each_entry_safe(event, tmp, &child->perf_event_list, owner_entry) { list_del_init(&event->owner_entry); /* * Ensure the list deletion is visible before we clear * the owner, closes a race against perf_release() where * we need to serialize on the owner->perf_event_mutex. */ smp_store_release(&event->owner, NULL); } mutex_unlock(&child->perf_event_mutex); perf_event_exit_task_context(child); /* * The perf_event_exit_task_context calls perf_event_task * with child's task_ctx, which generates EXIT events for * child contexts and sets child->perf_event_ctxp[] to NULL. * At this point we need to send EXIT events to cpu contexts. */ perf_event_task(child, NULL, 0); } static void perf_free_event(struct perf_event *event, struct perf_event_context *ctx) { struct perf_event *parent = event->parent; if (WARN_ON_ONCE(!parent)) return; mutex_lock(&parent->child_mutex); list_del_init(&event->child_list); mutex_unlock(&parent->child_mutex); put_event(parent); raw_spin_lock_irq(&ctx->lock); perf_group_detach(event); list_del_event(event, ctx); raw_spin_unlock_irq(&ctx->lock); free_event(event); } /* * Free a context as created by inheritance by perf_event_init_task() below, * used by fork() in case of fail. * * Even though the task has never lived, the context and events have been * exposed through the child_list, so we must take care tearing it all down. */ void perf_event_free_task(struct task_struct *task) { struct perf_event_context *ctx; struct perf_event *event, *tmp; ctx = rcu_access_pointer(task->perf_event_ctxp); if (!ctx) return; mutex_lock(&ctx->mutex); raw_spin_lock_irq(&ctx->lock); /* * Destroy the task <-> ctx relation and mark the context dead. * * This is important because even though the task hasn't been * exposed yet the context has been (through child_list). */ RCU_INIT_POINTER(task->perf_event_ctxp, NULL); WRITE_ONCE(ctx->task, TASK_TOMBSTONE); put_task_struct(task); /* cannot be last */ raw_spin_unlock_irq(&ctx->lock); list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) perf_free_event(event, ctx); mutex_unlock(&ctx->mutex); /* * perf_event_release_kernel() could've stolen some of our * child events and still have them on its free_list. In that * case we must wait for these events to have been freed (in * particular all their references to this task must've been * dropped). * * Without this copy_process() will unconditionally free this * task (irrespective of its reference count) and * _free_event()'s put_task_struct(event->hw.target) will be a * use-after-free. * * Wait for all events to drop their context reference. */ wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1); put_ctx(ctx); /* must be last */ } void perf_event_delayed_put(struct task_struct *task) { WARN_ON_ONCE(task->perf_event_ctxp); } struct file *perf_event_get(unsigned int fd) { struct file *file = fget(fd); if (!file) return ERR_PTR(-EBADF); if (file->f_op != &perf_fops) { fput(file); return ERR_PTR(-EBADF); } return file; } const struct perf_event *perf_get_event(struct file *file) { if (file->f_op != &perf_fops) return ERR_PTR(-EINVAL); return file->private_data; } const struct perf_event_attr *perf_event_attrs(struct perf_event *event) { if (!event) return ERR_PTR(-EINVAL); return &event->attr; } /* * Inherit an event from parent task to child task. * * Returns: * - valid pointer on success * - NULL for orphaned events * - IS_ERR() on error */ static struct perf_event * inherit_event(struct perf_event *parent_event, struct task_struct *parent, struct perf_event_context *parent_ctx, struct task_struct *child, struct perf_event *group_leader, struct perf_event_context *child_ctx) { enum perf_event_state parent_state = parent_event->state; struct perf_event_pmu_context *pmu_ctx; struct perf_event *child_event; unsigned long flags; /* * Instead of creating recursive hierarchies of events, * we link inherited events back to the original parent, * which has a filp for sure, which we use as the reference * count: */ if (parent_event->parent) parent_event = parent_event->parent; child_event = perf_event_alloc(&parent_event->attr, parent_event->cpu, child, group_leader, parent_event, NULL, NULL, -1); if (IS_ERR(child_event)) return child_event; pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event); if (IS_ERR(pmu_ctx)) { free_event(child_event); return ERR_CAST(pmu_ctx); } child_event->pmu_ctx = pmu_ctx; /* * is_orphaned_event() and list_add_tail(&parent_event->child_list) * must be under the same lock in order to serialize against * perf_event_release_kernel(), such that either we must observe * is_orphaned_event() or they will observe us on the child_list. */ mutex_lock(&parent_event->child_mutex); if (is_orphaned_event(parent_event) || !atomic_long_inc_not_zero(&parent_event->refcount)) { mutex_unlock(&parent_event->child_mutex); /* task_ctx_data is freed with child_ctx */ free_event(child_event); return NULL; } get_ctx(child_ctx); /* * Make the child state follow the state of the parent event, * not its attr.disabled bit. We hold the parent's mutex, * so we won't race with perf_event_{en, dis}able_family. */ if (parent_state >= PERF_EVENT_STATE_INACTIVE) child_event->state = PERF_EVENT_STATE_INACTIVE; else child_event->state = PERF_EVENT_STATE_OFF; if (parent_event->attr.freq) { u64 sample_period = parent_event->hw.sample_period; struct hw_perf_event *hwc = &child_event->hw; hwc->sample_period = sample_period; hwc->last_period = sample_period; local64_set(&hwc->period_left, sample_period); } child_event->ctx = child_ctx; child_event->overflow_handler = parent_event->overflow_handler; child_event->overflow_handler_context = parent_event->overflow_handler_context; /* * Precalculate sample_data sizes */ perf_event__header_size(child_event); perf_event__id_header_size(child_event); /* * Link it up in the child's context: */ raw_spin_lock_irqsave(&child_ctx->lock, flags); add_event_to_ctx(child_event, child_ctx); child_event->attach_state |= PERF_ATTACH_CHILD; raw_spin_unlock_irqrestore(&child_ctx->lock, flags); /* * Link this into the parent event's child list */ list_add_tail(&child_event->child_list, &parent_event->child_list); mutex_unlock(&parent_event->child_mutex); return child_event; } /* * Inherits an event group. * * This will quietly suppress orphaned events; !inherit_event() is not an error. * This matches with perf_event_release_kernel() removing all child events. * * Returns: * - 0 on success * - <0 on error */ static int inherit_group(struct perf_event *parent_event, struct task_struct *parent, struct perf_event_context *parent_ctx, struct task_struct *child, struct perf_event_context *child_ctx) { struct perf_event *leader; struct perf_event *sub; struct perf_event *child_ctr; leader = inherit_event(parent_event, parent, parent_ctx, child, NULL, child_ctx); if (IS_ERR(leader)) return PTR_ERR(leader); /* * @leader can be NULL here because of is_orphaned_event(). In this * case inherit_event() will create individual events, similar to what * perf_group_detach() would do anyway. */ for_each_sibling_event(sub, parent_event) { child_ctr = inherit_event(sub, parent, parent_ctx, child, leader, child_ctx); if (IS_ERR(child_ctr)) return PTR_ERR(child_ctr); if (sub->aux_event == parent_event && child_ctr && !perf_get_aux_event(child_ctr, leader)) return -EINVAL; } if (leader) leader->group_generation = parent_event->group_generation; return 0; } /* * Creates the child task context and tries to inherit the event-group. * * Clears @inherited_all on !attr.inherited or error. Note that we'll leave * inherited_all set when we 'fail' to inherit an orphaned event; this is * consistent with perf_event_release_kernel() removing all child events. * * Returns: * - 0 on success * - <0 on error */ static int inherit_task_group(struct perf_event *event, struct task_struct *parent, struct perf_event_context *parent_ctx, struct task_struct *child, u64 clone_flags, int *inherited_all) { struct perf_event_context *child_ctx; int ret; if (!event->attr.inherit || (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) || /* Do not inherit if sigtrap and signal handlers were cleared. */ (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) { *inherited_all = 0; return 0; } child_ctx = child->perf_event_ctxp; if (!child_ctx) { /* * This is executed from the parent task context, so * inherit events that have been marked for cloning. * First allocate and initialize a context for the * child. */ child_ctx = alloc_perf_context(child); if (!child_ctx) return -ENOMEM; child->perf_event_ctxp = child_ctx; } ret = inherit_group(event, parent, parent_ctx, child, child_ctx); if (ret) *inherited_all = 0; return ret; } /* * Initialize the perf_event context in task_struct */ static int perf_event_init_context(struct task_struct *child, u64 clone_flags) { struct perf_event_context *child_ctx, *parent_ctx; struct perf_event_context *cloned_ctx; struct perf_event *event; struct task_struct *parent = current; int inherited_all = 1; unsigned long flags; int ret = 0; if (likely(!parent->perf_event_ctxp)) return 0; /* * If the parent's context is a clone, pin it so it won't get * swapped under us. */ parent_ctx = perf_pin_task_context(parent); if (!parent_ctx) return 0; /* * No need to check if parent_ctx != NULL here; since we saw * it non-NULL earlier, the only reason for it to become NULL * is if we exit, and since we're currently in the middle of * a fork we can't be exiting at the same time. */ /* * Lock the parent list. No need to lock the child - not PID * hashed yet and not running, so nobody can access it. */ mutex_lock(&parent_ctx->mutex); /* * We dont have to disable NMIs - we are only looking at * the list, not manipulating it: */ perf_event_groups_for_each(event, &parent_ctx->pinned_groups) { ret = inherit_task_group(event, parent, parent_ctx, child, clone_flags, &inherited_all); if (ret) goto out_unlock; } /* * We can't hold ctx->lock when iterating the ->flexible_group list due * to allocations, but we need to prevent rotation because * rotate_ctx() will change the list from interrupt context. */ raw_spin_lock_irqsave(&parent_ctx->lock, flags); parent_ctx->rotate_disable = 1; raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); perf_event_groups_for_each(event, &parent_ctx->flexible_groups) { ret = inherit_task_group(event, parent, parent_ctx, child, clone_flags, &inherited_all); if (ret) goto out_unlock; } raw_spin_lock_irqsave(&parent_ctx->lock, flags); parent_ctx->rotate_disable = 0; child_ctx = child->perf_event_ctxp; if (child_ctx && inherited_all) { /* * Mark the child context as a clone of the parent * context, or of whatever the parent is a clone of. * * Note that if the parent is a clone, the holding of * parent_ctx->lock avoids it from being uncloned. */ cloned_ctx = parent_ctx->parent_ctx; if (cloned_ctx) { child_ctx->parent_ctx = cloned_ctx; child_ctx->parent_gen = parent_ctx->parent_gen; } else { child_ctx->parent_ctx = parent_ctx; child_ctx->parent_gen = parent_ctx->generation; } get_ctx(child_ctx->parent_ctx); } raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); out_unlock: mutex_unlock(&parent_ctx->mutex); perf_unpin_context(parent_ctx); put_ctx(parent_ctx); return ret; } /* * Initialize the perf_event context in task_struct */ int perf_event_init_task(struct task_struct *child, u64 clone_flags) { int ret; memset(child->perf_recursion, 0, sizeof(child->perf_recursion)); child->perf_event_ctxp = NULL; mutex_init(&child->perf_event_mutex); INIT_LIST_HEAD(&child->perf_event_list); ret = perf_event_init_context(child, clone_flags); if (ret) { perf_event_free_task(child); return ret; } return 0; } static void __init perf_event_init_all_cpus(void) { struct swevent_htable *swhash; struct perf_cpu_context *cpuctx; int cpu; zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL); for_each_possible_cpu(cpu) { swhash = &per_cpu(swevent_htable, cpu); mutex_init(&swhash->hlist_mutex); INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); __perf_event_init_context(&cpuctx->ctx); lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask); cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default); cpuctx->heap = cpuctx->heap_default; } } static void perf_swevent_init_cpu(unsigned int cpu) { struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); mutex_lock(&swhash->hlist_mutex); if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { struct swevent_hlist *hlist; hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); WARN_ON(!hlist); rcu_assign_pointer(swhash->swevent_hlist, hlist); } mutex_unlock(&swhash->hlist_mutex); } #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE static void __perf_event_exit_context(void *__info) { struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct perf_event_context *ctx = __info; struct perf_event *event; raw_spin_lock(&ctx->lock); ctx_sched_out(ctx, EVENT_TIME); list_for_each_entry(event, &ctx->event_list, event_entry) __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); raw_spin_unlock(&ctx->lock); } static void perf_event_exit_cpu_context(int cpu) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; // XXX simplify cpuctx->online mutex_lock(&pmus_lock); cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); ctx = &cpuctx->ctx; mutex_lock(&ctx->mutex); smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); cpuctx->online = 0; mutex_unlock(&ctx->mutex); cpumask_clear_cpu(cpu, perf_online_mask); mutex_unlock(&pmus_lock); } #else static void perf_event_exit_cpu_context(int cpu) { } #endif int perf_event_init_cpu(unsigned int cpu) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; perf_swevent_init_cpu(cpu); mutex_lock(&pmus_lock); cpumask_set_cpu(cpu, perf_online_mask); cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); ctx = &cpuctx->ctx; mutex_lock(&ctx->mutex); cpuctx->online = 1; mutex_unlock(&ctx->mutex); mutex_unlock(&pmus_lock); return 0; } int perf_event_exit_cpu(unsigned int cpu) { perf_event_exit_cpu_context(cpu); return 0; } static int perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) { int cpu; for_each_online_cpu(cpu) perf_event_exit_cpu(cpu); return NOTIFY_OK; } /* * Run the perf reboot notifier at the very last possible moment so that * the generic watchdog code runs as long as possible. */ static struct notifier_block perf_reboot_notifier = { .notifier_call = perf_reboot, .priority = INT_MIN, }; void __init perf_event_init(void) { int ret; idr_init(&pmu_idr); perf_event_init_all_cpus(); init_srcu_struct(&pmus_srcu); perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); perf_pmu_register(&perf_cpu_clock, "cpu_clock", -1); perf_pmu_register(&perf_task_clock, "task_clock", -1); perf_tp_register(); perf_event_init_cpu(smp_processor_id()); register_reboot_notifier(&perf_reboot_notifier); ret = init_hw_breakpoint(); WARN(ret, "hw_breakpoint initialization failed with: %d", ret); perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC); /* * Build time assertion that we keep the data_head at the intended * location. IOW, validation we got the __reserved[] size right. */ BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) != 1024); } ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) { struct perf_pmu_events_attr *pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr); if (pmu_attr->event_str) return sprintf(page, "%s\n", pmu_attr->event_str); return 0; } EXPORT_SYMBOL_GPL(perf_event_sysfs_show); static int __init perf_event_sysfs_init(void) { struct pmu *pmu; int ret; mutex_lock(&pmus_lock); ret = bus_register(&pmu_bus); if (ret) goto unlock; list_for_each_entry(pmu, &pmus, entry) { if (pmu->dev) continue; ret = pmu_dev_alloc(pmu); WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); } pmu_bus_running = 1; ret = 0; unlock: mutex_unlock(&pmus_lock); return ret; } device_initcall(perf_event_sysfs_init); #ifdef CONFIG_CGROUP_PERF static struct cgroup_subsys_state * perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct perf_cgroup *jc; jc = kzalloc(sizeof(*jc), GFP_KERNEL); if (!jc) return ERR_PTR(-ENOMEM); jc->info = alloc_percpu(struct perf_cgroup_info); if (!jc->info) { kfree(jc); return ERR_PTR(-ENOMEM); } return &jc->css; } static void perf_cgroup_css_free(struct cgroup_subsys_state *css) { struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); free_percpu(jc->info); kfree(jc); } static int perf_cgroup_css_online(struct cgroup_subsys_state *css) { perf_event_cgroup(css->cgroup); return 0; } static int __perf_cgroup_move(void *info) { struct task_struct *task = info; preempt_disable(); perf_cgroup_switch(task); preempt_enable(); return 0; } static void perf_cgroup_attach(struct cgroup_taskset *tset) { struct task_struct *task; struct cgroup_subsys_state *css; cgroup_taskset_for_each(task, css, tset) task_function_call(task, __perf_cgroup_move, task); } struct cgroup_subsys perf_event_cgrp_subsys = { .css_alloc = perf_cgroup_css_alloc, .css_free = perf_cgroup_css_free, .css_online = perf_cgroup_css_online, .attach = perf_cgroup_attach, /* * Implicitly enable on dfl hierarchy so that perf events can * always be filtered by cgroup2 path as long as perf_event * controller is not mounted on a legacy hierarchy. */ .implicit_on_dfl = true, .threaded = true, }; #endif /* CONFIG_CGROUP_PERF */ DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);
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