| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Steven Rostedt | 20174 | 81.88% | 253 | 63.89% |
| Namhyung Kim | 1127 | 4.57% | 16 | 4.04% |
| Masami Hiramatsu | 1046 | 4.25% | 7 | 1.77% |
| Jiri Olsa | 490 | 1.99% | 13 | 3.28% |
| Joel A Fernandes | 305 | 1.24% | 2 | 0.51% |
| Li Zefan | 301 | 1.22% | 16 | 4.04% |
| Dmitry Safonov | 224 | 0.91% | 4 | 1.01% |
| Arnaldo Carvalho de Melo | 107 | 0.43% | 1 | 0.25% |
| Stefan Assmann | 107 | 0.43% | 1 | 0.25% |
| Frédéric Weisbecker | 86 | 0.35% | 7 | 1.77% |
| Chase Douglas | 80 | 0.32% | 1 | 0.25% |
| Chunyan Zhang | 68 | 0.28% | 1 | 0.25% |
| Jiri Slaby | 49 | 0.20% | 4 | 1.01% |
| Naveen N. Rao | 47 | 0.19% | 2 | 0.51% |
| Todd E Brandt | 40 | 0.16% | 1 | 0.25% |
| Pratyush Anand | 36 | 0.15% | 1 | 0.25% |
| Umesh Tiwari | 33 | 0.13% | 1 | 0.25% |
| Abhishek Sagar | 32 | 0.13% | 5 | 1.26% |
| Thiago Jung Bauermann | 31 | 0.13% | 1 | 0.25% |
| Xiao Guangrong | 27 | 0.11% | 2 | 0.51% |
| Lai Jiangshan | 18 | 0.07% | 3 | 0.76% |
| Petr Mladek | 17 | 0.07% | 1 | 0.25% |
| Paul E. McKenney | 15 | 0.06% | 2 | 0.51% |
| Liming Wang | 14 | 0.06% | 3 | 0.76% |
| Salvatore Mesoraca | 14 | 0.06% | 1 | 0.25% |
| Juri Lelli | 13 | 0.05% | 1 | 0.25% |
| Arnd Bergmann | 13 | 0.05% | 2 | 0.51% |
| Ingo Molnar | 13 | 0.05% | 5 | 1.26% |
| Rasmus Villemoes | 12 | 0.05% | 2 | 0.51% |
| Wang Nan | 12 | 0.05% | 1 | 0.25% |
| Chris Wright | 7 | 0.03% | 1 | 0.25% |
| Vasily Gorbik | 5 | 0.02% | 1 | 0.25% |
| Geliang Tang | 5 | 0.02% | 1 | 0.25% |
| Gustavo A. R. Silva | 5 | 0.02% | 1 | 0.25% |
| Christoph Lameter | 4 | 0.02% | 1 | 0.25% |
| Tom Zanussi | 4 | 0.02% | 1 | 0.25% |
| Peter Hüwe | 3 | 0.01% | 1 | 0.25% |
| Tejun Heo | 3 | 0.01% | 1 | 0.25% |
| Joe Perches | 3 | 0.01% | 1 | 0.25% |
| Dan Carpenter | 3 | 0.01% | 2 | 0.51% |
| Kees Cook | 3 | 0.01% | 1 | 0.25% |
| Paul Gortmaker | 3 | 0.01% | 1 | 0.25% |
| Alexei Starovoitov | 3 | 0.01% | 1 | 0.25% |
| Yisheng Xie | 3 | 0.01% | 1 | 0.25% |
| Thomas Meyer | 3 | 0.01% | 1 | 0.25% |
| James Morris | 2 | 0.01% | 1 | 0.25% |
| GuoWen Li | 2 | 0.01% | 1 | 0.25% |
| Atsushi Tsuji | 2 | 0.01% | 1 | 0.25% |
| Jan Kiszka | 2 | 0.01% | 1 | 0.25% |
| Thomas Gleixner | 2 | 0.01% | 1 | 0.25% |
| Chen LinX | 2 | 0.01% | 1 | 0.25% |
| Chen Gang S | 2 | 0.01% | 1 | 0.25% |
| Oleg Nesterov | 2 | 0.01% | 1 | 0.25% |
| Sasha Levin | 2 | 0.01% | 1 | 0.25% |
| Jiaxing Wang | 2 | 0.01% | 1 | 0.25% |
| Michael Ellerman | 1 | 0.00% | 1 | 0.25% |
| Luis Henriques | 1 | 0.00% | 1 | 0.25% |
| Nadia Yvette Chambers | 1 | 0.00% | 1 | 0.25% |
| Chunyu Hu | 1 | 0.00% | 1 | 0.25% |
| Uwe Kleine-König | 1 | 0.00% | 1 | 0.25% |
| Abel Vesa | 1 | 0.00% | 1 | 0.25% |
| Motohiro Kosaki | 1 | 0.00% | 1 | 0.25% |
| Shaohua Li | 1 | 0.00% | 1 | 0.25% |
| Li Bin | 1 | 0.00% | 1 | 0.25% |
| Miao Xie | 1 | 0.00% | 1 | 0.25% |
| Total | 24638 | 396 |
// SPDX-License-Identifier: GPL-2.0 /* * Infrastructure for profiling code inserted by 'gcc -pg'. * * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com> * * Originally ported from the -rt patch by: * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com> * * Based on code in the latency_tracer, that is: * * Copyright (C) 2004-2006 Ingo Molnar * Copyright (C) 2004 Nadia Yvette Chambers */ #include <linux/stop_machine.h> #include <linux/clocksource.h> #include <linux/sched/task.h> #include <linux/kallsyms.h> #include <linux/seq_file.h> #include <linux/tracefs.h> #include <linux/hardirq.h> #include <linux/kthread.h> #include <linux/uaccess.h> #include <linux/bsearch.h> #include <linux/module.h> #include <linux/ftrace.h> #include <linux/sysctl.h> #include <linux/slab.h> #include <linux/ctype.h> #include <linux/sort.h> #include <linux/list.h> #include <linux/hash.h> #include <linux/rcupdate.h> #include <trace/events/sched.h> #include <asm/sections.h> #include <asm/setup.h> #include "ftrace_internal.h" #include "trace_output.h" #include "trace_stat.h" #define FTRACE_WARN_ON(cond) \ ({ \ int ___r = cond; \ if (WARN_ON(___r)) \ ftrace_kill(); \ ___r; \ }) #define FTRACE_WARN_ON_ONCE(cond) \ ({ \ int ___r = cond; \ if (WARN_ON_ONCE(___r)) \ ftrace_kill(); \ ___r; \ }) /* hash bits for specific function selection */ #define FTRACE_HASH_BITS 7 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS) #define FTRACE_HASH_DEFAULT_BITS 10 #define FTRACE_HASH_MAX_BITS 12 #ifdef CONFIG_DYNAMIC_FTRACE #define INIT_OPS_HASH(opsname) \ .func_hash = &opsname.local_hash, \ .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), #define ASSIGN_OPS_HASH(opsname, val) \ .func_hash = val, \ .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock), #else #define INIT_OPS_HASH(opsname) #define ASSIGN_OPS_HASH(opsname, val) #endif enum { FTRACE_MODIFY_ENABLE_FL = (1 << 0), FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1), }; struct ftrace_ops ftrace_list_end __read_mostly = { .func = ftrace_stub, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB, INIT_OPS_HASH(ftrace_list_end) }; /* ftrace_enabled is a method to turn ftrace on or off */ int ftrace_enabled __read_mostly; static int last_ftrace_enabled; /* Current function tracing op */ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end; /* What to set function_trace_op to */ static struct ftrace_ops *set_function_trace_op; static bool ftrace_pids_enabled(struct ftrace_ops *ops) { struct trace_array *tr; if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private) return false; tr = ops->private; return tr->function_pids != NULL; } static void ftrace_update_trampoline(struct ftrace_ops *ops); /* * ftrace_disabled is set when an anomaly is discovered. * ftrace_disabled is much stronger than ftrace_enabled. */ static int ftrace_disabled __read_mostly; DEFINE_MUTEX(ftrace_lock); struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; struct ftrace_ops global_ops; #if ARCH_SUPPORTS_FTRACE_OPS static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs); #else /* See comment below, where ftrace_ops_list_func is defined */ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip); #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops) #endif static inline void ftrace_ops_init(struct ftrace_ops *ops) { #ifdef CONFIG_DYNAMIC_FTRACE if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) { mutex_init(&ops->local_hash.regex_lock); ops->func_hash = &ops->local_hash; ops->flags |= FTRACE_OPS_FL_INITIALIZED; } #endif } static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { struct trace_array *tr = op->private; if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid)) return; op->saved_func(ip, parent_ip, op, regs); } static void ftrace_sync(struct work_struct *work) { /* * This function is just a stub to implement a hard force * of synchronize_rcu(). This requires synchronizing * tasks even in userspace and idle. * * Yes, function tracing is rude. */ } static void ftrace_sync_ipi(void *data) { /* Probably not needed, but do it anyway */ smp_rmb(); } static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops) { /* * If this is a dynamic, RCU, or per CPU ops, or we force list func, * then it needs to call the list anyway. */ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC) return ftrace_ops_list_func; return ftrace_ops_get_func(ops); } static void update_ftrace_function(void) { ftrace_func_t func; /* * Prepare the ftrace_ops that the arch callback will use. * If there's only one ftrace_ops registered, the ftrace_ops_list * will point to the ops we want. */ set_function_trace_op = rcu_dereference_protected(ftrace_ops_list, lockdep_is_held(&ftrace_lock)); /* If there's no ftrace_ops registered, just call the stub function */ if (set_function_trace_op == &ftrace_list_end) { func = ftrace_stub; /* * If we are at the end of the list and this ops is * recursion safe and not dynamic and the arch supports passing ops, * then have the mcount trampoline call the function directly. */ } else if (rcu_dereference_protected(ftrace_ops_list->next, lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { func = ftrace_ops_get_list_func(ftrace_ops_list); } else { /* Just use the default ftrace_ops */ set_function_trace_op = &ftrace_list_end; func = ftrace_ops_list_func; } update_function_graph_func(); /* If there's no change, then do nothing more here */ if (ftrace_trace_function == func) return; /* * If we are using the list function, it doesn't care * about the function_trace_ops. */ if (func == ftrace_ops_list_func) { ftrace_trace_function = func; /* * Don't even bother setting function_trace_ops, * it would be racy to do so anyway. */ return; } #ifndef CONFIG_DYNAMIC_FTRACE /* * For static tracing, we need to be a bit more careful. * The function change takes affect immediately. Thus, * we need to coorditate the setting of the function_trace_ops * with the setting of the ftrace_trace_function. * * Set the function to the list ops, which will call the * function we want, albeit indirectly, but it handles the * ftrace_ops and doesn't depend on function_trace_op. */ ftrace_trace_function = ftrace_ops_list_func; /* * Make sure all CPUs see this. Yes this is slow, but static * tracing is slow and nasty to have enabled. */ schedule_on_each_cpu(ftrace_sync); /* Now all cpus are using the list ops. */ function_trace_op = set_function_trace_op; /* Make sure the function_trace_op is visible on all CPUs */ smp_wmb(); /* Nasty way to force a rmb on all cpus */ smp_call_function(ftrace_sync_ipi, NULL, 1); /* OK, we are all set to update the ftrace_trace_function now! */ #endif /* !CONFIG_DYNAMIC_FTRACE */ ftrace_trace_function = func; } static void add_ftrace_ops(struct ftrace_ops __rcu **list, struct ftrace_ops *ops) { rcu_assign_pointer(ops->next, *list); /* * We are entering ops into the list but another * CPU might be walking that list. We need to make sure * the ops->next pointer is valid before another CPU sees * the ops pointer included into the list. */ rcu_assign_pointer(*list, ops); } static int remove_ftrace_ops(struct ftrace_ops __rcu **list, struct ftrace_ops *ops) { struct ftrace_ops **p; /* * If we are removing the last function, then simply point * to the ftrace_stub. */ if (rcu_dereference_protected(*list, lockdep_is_held(&ftrace_lock)) == ops && rcu_dereference_protected(ops->next, lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { *list = &ftrace_list_end; return 0; } for (p = list; *p != &ftrace_list_end; p = &(*p)->next) if (*p == ops) break; if (*p != ops) return -1; *p = (*p)->next; return 0; } static void ftrace_update_trampoline(struct ftrace_ops *ops); int __register_ftrace_function(struct ftrace_ops *ops) { if (ops->flags & FTRACE_OPS_FL_DELETED) return -EINVAL; if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EBUSY; #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* * If the ftrace_ops specifies SAVE_REGS, then it only can be used * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set. * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant. */ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS && !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)) return -EINVAL; if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED) ops->flags |= FTRACE_OPS_FL_SAVE_REGS; #endif if (!core_kernel_data((unsigned long)ops)) ops->flags |= FTRACE_OPS_FL_DYNAMIC; add_ftrace_ops(&ftrace_ops_list, ops); /* Always save the function, and reset at unregistering */ ops->saved_func = ops->func; if (ftrace_pids_enabled(ops)) ops->func = ftrace_pid_func; ftrace_update_trampoline(ops); if (ftrace_enabled) update_ftrace_function(); return 0; } int __unregister_ftrace_function(struct ftrace_ops *ops) { int ret; if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED))) return -EBUSY; ret = remove_ftrace_ops(&ftrace_ops_list, ops); if (ret < 0) return ret; if (ftrace_enabled) update_ftrace_function(); ops->func = ops->saved_func; return 0; } static void ftrace_update_pid_func(void) { struct ftrace_ops *op; /* Only do something if we are tracing something */ if (ftrace_trace_function == ftrace_stub) return; do_for_each_ftrace_op(op, ftrace_ops_list) { if (op->flags & FTRACE_OPS_FL_PID) { op->func = ftrace_pids_enabled(op) ? ftrace_pid_func : op->saved_func; ftrace_update_trampoline(op); } } while_for_each_ftrace_op(op); update_ftrace_function(); } #ifdef CONFIG_FUNCTION_PROFILER struct ftrace_profile { struct hlist_node node; unsigned long ip; unsigned long counter; #ifdef CONFIG_FUNCTION_GRAPH_TRACER unsigned long long time; unsigned long long time_squared; #endif }; struct ftrace_profile_page { struct ftrace_profile_page *next; unsigned long index; struct ftrace_profile records[]; }; struct ftrace_profile_stat { atomic_t disabled; struct hlist_head *hash; struct ftrace_profile_page *pages; struct ftrace_profile_page *start; struct tracer_stat stat; }; #define PROFILE_RECORDS_SIZE \ (PAGE_SIZE - offsetof(struct ftrace_profile_page, records)) #define PROFILES_PER_PAGE \ (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile)) static int ftrace_profile_enabled __read_mostly; /* ftrace_profile_lock - synchronize the enable and disable of the profiler */ static DEFINE_MUTEX(ftrace_profile_lock); static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats); #define FTRACE_PROFILE_HASH_BITS 10 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS) static void * function_stat_next(void *v, int idx) { struct ftrace_profile *rec = v; struct ftrace_profile_page *pg; pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK); again: if (idx != 0) rec++; if ((void *)rec >= (void *)&pg->records[pg->index]) { pg = pg->next; if (!pg) return NULL; rec = &pg->records[0]; if (!rec->counter) goto again; } return rec; } static void *function_stat_start(struct tracer_stat *trace) { struct ftrace_profile_stat *stat = container_of(trace, struct ftrace_profile_stat, stat); if (!stat || !stat->start) return NULL; return function_stat_next(&stat->start->records[0], 0); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* function graph compares on total time */ static int function_stat_cmp(void *p1, void *p2) { struct ftrace_profile *a = p1; struct ftrace_profile *b = p2; if (a->time < b->time) return -1; if (a->time > b->time) return 1; else return 0; } #else /* not function graph compares against hits */ static int function_stat_cmp(void *p1, void *p2) { struct ftrace_profile *a = p1; struct ftrace_profile *b = p2; if (a->counter < b->counter) return -1; if (a->counter > b->counter) return 1; else return 0; } #endif static int function_stat_headers(struct seq_file *m) { #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_puts(m, " Function " "Hit Time Avg s^2\n" " -------- " "--- ---- --- ---\n"); #else seq_puts(m, " Function Hit\n" " -------- ---\n"); #endif return 0; } static int function_stat_show(struct seq_file *m, void *v) { struct ftrace_profile *rec = v; char str[KSYM_SYMBOL_LEN]; int ret = 0; #ifdef CONFIG_FUNCTION_GRAPH_TRACER static struct trace_seq s; unsigned long long avg; unsigned long long stddev; #endif mutex_lock(&ftrace_profile_lock); /* we raced with function_profile_reset() */ if (unlikely(rec->counter == 0)) { ret = -EBUSY; goto out; } #ifdef CONFIG_FUNCTION_GRAPH_TRACER avg = rec->time; do_div(avg, rec->counter); if (tracing_thresh && (avg < tracing_thresh)) goto out; #endif kallsyms_lookup(rec->ip, NULL, NULL, NULL, str); seq_printf(m, " %-30.30s %10lu", str, rec->counter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER seq_puts(m, " "); /* Sample standard deviation (s^2) */ if (rec->counter <= 1) stddev = 0; else { /* * Apply Welford's method: * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) */ stddev = rec->counter * rec->time_squared - rec->time * rec->time; /* * Divide only 1000 for ns^2 -> us^2 conversion. * trace_print_graph_duration will divide 1000 again. */ do_div(stddev, rec->counter * (rec->counter - 1) * 1000); } trace_seq_init(&s); trace_print_graph_duration(rec->time, &s); trace_seq_puts(&s, " "); trace_print_graph_duration(avg, &s); trace_seq_puts(&s, " "); trace_print_graph_duration(stddev, &s); trace_print_seq(m, &s); #endif seq_putc(m, '\n'); out: mutex_unlock(&ftrace_profile_lock); return ret; } static void ftrace_profile_reset(struct ftrace_profile_stat *stat) { struct ftrace_profile_page *pg; pg = stat->pages = stat->start; while (pg) { memset(pg->records, 0, PROFILE_RECORDS_SIZE); pg->index = 0; pg = pg->next; } memset(stat->hash, 0, FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head)); } int ftrace_profile_pages_init(struct ftrace_profile_stat *stat) { struct ftrace_profile_page *pg; int functions; int pages; int i; /* If we already allocated, do nothing */ if (stat->pages) return 0; stat->pages = (void *)get_zeroed_page(GFP_KERNEL); if (!stat->pages) return -ENOMEM; #ifdef CONFIG_DYNAMIC_FTRACE functions = ftrace_update_tot_cnt; #else /* * We do not know the number of functions that exist because * dynamic tracing is what counts them. With past experience * we have around 20K functions. That should be more than enough. * It is highly unlikely we will execute every function in * the kernel. */ functions = 20000; #endif pg = stat->start = stat->pages; pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE); for (i = 1; i < pages; i++) { pg->next = (void *)get_zeroed_page(GFP_KERNEL); if (!pg->next) goto out_free; pg = pg->next; } return 0; out_free: pg = stat->start; while (pg) { unsigned long tmp = (unsigned long)pg; pg = pg->next; free_page(tmp); } stat->pages = NULL; stat->start = NULL; return -ENOMEM; } static int ftrace_profile_init_cpu(int cpu) { struct ftrace_profile_stat *stat; int size; stat = &per_cpu(ftrace_profile_stats, cpu); if (stat->hash) { /* If the profile is already created, simply reset it */ ftrace_profile_reset(stat); return 0; } /* * We are profiling all functions, but usually only a few thousand * functions are hit. We'll make a hash of 1024 items. */ size = FTRACE_PROFILE_HASH_SIZE; stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL); if (!stat->hash) return -ENOMEM; /* Preallocate the function profiling pages */ if (ftrace_profile_pages_init(stat) < 0) { kfree(stat->hash); stat->hash = NULL; return -ENOMEM; } return 0; } static int ftrace_profile_init(void) { int cpu; int ret = 0; for_each_possible_cpu(cpu) { ret = ftrace_profile_init_cpu(cpu); if (ret) break; } return ret; } /* interrupts must be disabled */ static struct ftrace_profile * ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip) { struct ftrace_profile *rec; struct hlist_head *hhd; unsigned long key; key = hash_long(ip, FTRACE_PROFILE_HASH_BITS); hhd = &stat->hash[key]; if (hlist_empty(hhd)) return NULL; hlist_for_each_entry_rcu_notrace(rec, hhd, node) { if (rec->ip == ip) return rec; } return NULL; } static void ftrace_add_profile(struct ftrace_profile_stat *stat, struct ftrace_profile *rec) { unsigned long key; key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS); hlist_add_head_rcu(&rec->node, &stat->hash[key]); } /* * The memory is already allocated, this simply finds a new record to use. */ static struct ftrace_profile * ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip) { struct ftrace_profile *rec = NULL; /* prevent recursion (from NMIs) */ if (atomic_inc_return(&stat->disabled) != 1) goto out; /* * Try to find the function again since an NMI * could have added it */ rec = ftrace_find_profiled_func(stat, ip); if (rec) goto out; if (stat->pages->index == PROFILES_PER_PAGE) { if (!stat->pages->next) goto out; stat->pages = stat->pages->next; } rec = &stat->pages->records[stat->pages->index++]; rec->ip = ip; ftrace_add_profile(stat, rec); out: atomic_dec(&stat->disabled); return rec; } static void function_profile_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct pt_regs *regs) { struct ftrace_profile_stat *stat; struct ftrace_profile *rec; unsigned long flags; if (!ftrace_profile_enabled) return; local_irq_save(flags); stat = this_cpu_ptr(&ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; rec = ftrace_find_profiled_func(stat, ip); if (!rec) { rec = ftrace_profile_alloc(stat, ip); if (!rec) goto out; } rec->counter++; out: local_irq_restore(flags); } #ifdef CONFIG_FUNCTION_GRAPH_TRACER static bool fgraph_graph_time = true; void ftrace_graph_graph_time_control(bool enable) { fgraph_graph_time = enable; } static int profile_graph_entry(struct ftrace_graph_ent *trace) { struct ftrace_ret_stack *ret_stack; function_profile_call(trace->func, 0, NULL, NULL); /* If function graph is shutting down, ret_stack can be NULL */ if (!current->ret_stack) return 0; ret_stack = ftrace_graph_get_ret_stack(current, 0); if (ret_stack) ret_stack->subtime = 0; return 1; } static void profile_graph_return(struct ftrace_graph_ret *trace) { struct ftrace_ret_stack *ret_stack; struct ftrace_profile_stat *stat; unsigned long long calltime; struct ftrace_profile *rec; unsigned long flags; local_irq_save(flags); stat = this_cpu_ptr(&ftrace_profile_stats); if (!stat->hash || !ftrace_profile_enabled) goto out; /* If the calltime was zero'd ignore it */ if (!trace->calltime) goto out; calltime = trace->rettime - trace->calltime; if (!fgraph_graph_time) { /* Append this call time to the parent time to subtract */ ret_stack = ftrace_graph_get_ret_stack(current, 1); if (ret_stack) ret_stack->subtime += calltime; ret_stack = ftrace_graph_get_ret_stack(current, 0); if (ret_stack && ret_stack->subtime < calltime) calltime -= ret_stack->subtime; else calltime = 0; } rec = ftrace_find_profiled_func(stat, trace->func); if (rec) { rec->time += calltime; rec->time_squared += calltime * calltime; } out: local_irq_restore(flags); } static struct fgraph_ops fprofiler_ops = { .entryfunc = &profile_graph_entry, .retfunc = &profile_graph_return, }; static int register_ftrace_profiler(void) { return register_ftrace_graph(&fprofiler_ops); } static void unregister_ftrace_profiler(void) { unregister_ftrace_graph(&fprofiler_ops); } #else static struct ftrace_ops ftrace_profile_ops __read_mostly = { .func = function_profile_call, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED, INIT_OPS_HASH(ftrace_profile_ops) }; static int register_ftrace_profiler(void) { return register_ftrace_function(&ftrace_profile_ops); } static void unregister_ftrace_profiler(void) { unregister_ftrace_function(&ftrace_profile_ops); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ static ssize_t ftrace_profile_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { unsigned long val; int ret; ret = kstrtoul_from_user(ubuf, cnt, 10, &val); if (ret) return ret; val = !!val; mutex_lock(&ftrace_profile_lock); if (ftrace_profile_enabled ^ val) { if (val) { ret = ftrace_profile_init(); if (ret < 0) { cnt = ret; goto out; } ret = register_ftrace_profiler(); if (ret < 0) { cnt = ret; goto out; } ftrace_profile_enabled = 1; } else { ftrace_profile_enabled = 0; /* * unregister_ftrace_profiler calls stop_machine * so this acts like an synchronize_rcu. */ unregister_ftrace_profiler(); } } out: mutex_unlock(&ftrace_profile_lock); *ppos += cnt; return cnt; } static ssize_t ftrace_profile_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { char buf[64]; /* big enough to hold a number */ int r; r = sprintf(buf, "%u\n", ftrace_profile_enabled); return simple_read_from_buffer(ubuf, cnt, ppos, buf, r); } static const struct file_operations ftrace_profile_fops = { .open = tracing_open_generic, .read = ftrace_profile_read, .write = ftrace_profile_write, .llseek = default_llseek, }; /* used to initialize the real stat files */ static struct tracer_stat function_stats __initdata = { .name = "functions", .stat_start = function_stat_start, .stat_next = function_stat_next, .stat_cmp = function_stat_cmp, .stat_headers = function_stat_headers, .stat_show = function_stat_show }; static __init void ftrace_profile_tracefs(struct dentry *d_tracer) { struct ftrace_profile_stat *stat; struct dentry *entry; char *name; int ret; int cpu; for_each_possible_cpu(cpu) { stat = &per_cpu(ftrace_profile_stats, cpu); name = kasprintf(GFP_KERNEL, "function%d", cpu); if (!name) { /* * The files created are permanent, if something happens * we still do not free memory. */ WARN(1, "Could not allocate stat file for cpu %d\n", cpu); return; } stat->stat = function_stats; stat->stat.name = name; ret = register_stat_tracer(&stat->stat); if (ret) { WARN(1, "Could not register function stat for cpu %d\n", cpu); kfree(name); return; } } entry = tracefs_create_file("function_profile_enabled", 0644, d_tracer, NULL, &ftrace_profile_fops); if (!entry) pr_warn("Could not create tracefs 'function_profile_enabled' entry\n"); } #else /* CONFIG_FUNCTION_PROFILER */ static __init void ftrace_profile_tracefs(struct dentry *d_tracer) { } #endif /* CONFIG_FUNCTION_PROFILER */ #ifdef CONFIG_DYNAMIC_FTRACE static struct ftrace_ops *removed_ops; /* * Set when doing a global update, like enabling all recs or disabling them. * It is not set when just updating a single ftrace_ops. */ static bool update_all_ops; #ifndef CONFIG_FTRACE_MCOUNT_RECORD # error Dynamic ftrace depends on MCOUNT_RECORD #endif struct ftrace_func_entry { struct hlist_node hlist; unsigned long ip; }; struct ftrace_func_probe { struct ftrace_probe_ops *probe_ops; struct ftrace_ops ops; struct trace_array *tr; struct list_head list; void *data; int ref; }; /* * We make these constant because no one should touch them, * but they are used as the default "empty hash", to avoid allocating * it all the time. These are in a read only section such that if * anyone does try to modify it, it will cause an exception. */ static const struct hlist_head empty_buckets[1]; static const struct ftrace_hash empty_hash = { .buckets = (struct hlist_head *)empty_buckets, }; #define EMPTY_HASH ((struct ftrace_hash *)&empty_hash) struct ftrace_ops global_ops = { .func = ftrace_stub, .local_hash.notrace_hash = EMPTY_HASH, .local_hash.filter_hash = EMPTY_HASH, INIT_OPS_HASH(global_ops) .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID, }; /* * Used by the stack undwinder to know about dynamic ftrace trampolines. */ struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr) { struct ftrace_ops *op = NULL; /* * Some of the ops may be dynamically allocated, * they are freed after a synchronize_rcu(). */ preempt_disable_notrace(); do_for_each_ftrace_op(op, ftrace_ops_list) { /* * This is to check for dynamically allocated trampolines. * Trampolines that are in kernel text will have * core_kernel_text() return true. */ if (op->trampoline && op->trampoline_size) if (addr >= op->trampoline && addr < op->trampoline + op->trampoline_size) { preempt_enable_notrace(); return op; } } while_for_each_ftrace_op(op); preempt_enable_notrace(); return NULL; } /* * This is used by __kernel_text_address() to return true if the * address is on a dynamically allocated trampoline that would * not return true for either core_kernel_text() or * is_module_text_address(). */ bool is_ftrace_trampoline(unsigned long addr) { return ftrace_ops_trampoline(addr) != NULL; } struct ftrace_page { struct ftrace_page *next; struct dyn_ftrace *records; int index; int size; }; #define ENTRY_SIZE sizeof(struct dyn_ftrace) #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE) /* estimate from running different kernels */ #define NR_TO_INIT 10000 static struct ftrace_page *ftrace_pages_start; static struct ftrace_page *ftrace_pages; static __always_inline unsigned long ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip) { if (hash->size_bits > 0) return hash_long(ip, hash->size_bits); return 0; } /* Only use this function if ftrace_hash_empty() has already been tested */ static __always_inline struct ftrace_func_entry * __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) { unsigned long key; struct ftrace_func_entry *entry; struct hlist_head *hhd; key = ftrace_hash_key(hash, ip); hhd = &hash->buckets[key]; hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) { if (entry->ip == ip) return entry; } return NULL; } /** * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash * @hash: The hash to look at * @ip: The instruction pointer to test * * Search a given @hash to see if a given instruction pointer (@ip) * exists in it. * * Returns the entry that holds the @ip if found. NULL otherwise. */ struct ftrace_func_entry * ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip) { if (ftrace_hash_empty(hash)) return NULL; return __ftrace_lookup_ip(hash, ip); } static void __add_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) { struct hlist_head *hhd; unsigned long key; key = ftrace_hash_key(hash, entry->ip); hhd = &hash->buckets[key]; hlist_add_head(&entry->hlist, hhd); hash->count++; } static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip) { struct ftrace_func_entry *entry; entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) return -ENOMEM; entry->ip = ip; __add_hash_entry(hash, entry); return 0; } static void free_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) { hlist_del(&entry->hlist); kfree(entry); hash->count--; } static void remove_hash_entry(struct ftrace_hash *hash, struct ftrace_func_entry *entry) { hlist_del_rcu(&entry->hlist); hash->count--; } static void ftrace_hash_clear(struct ftrace_hash *hash) { struct hlist_head *hhd; struct hlist_node *tn; struct ftrace_func_entry *entry; int size = 1 << hash->size_bits; int i; if (!hash->count) return; for (i = 0; i < size; i++) { hhd = &hash->buckets[i]; hlist_for_each_entry_safe(entry, tn, hhd, hlist) free_hash_entry(hash, entry); } FTRACE_WARN_ON(hash->count); } static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod) { list_del(&ftrace_mod->list); kfree(ftrace_mod->module); kfree(ftrace_mod->func); kfree(ftrace_mod); } static void clear_ftrace_mod_list(struct list_head *head) { struct ftrace_mod_load *p, *n; /* stack tracer isn't supported yet */ if (!head) return; mutex_lock(&ftrace_lock); list_for_each_entry_safe(p, n, head, list) free_ftrace_mod(p); mutex_unlock(&ftrace_lock); } static void free_ftrace_hash(struct ftrace_hash *hash) { if (!hash || hash == EMPTY_HASH) return; ftrace_hash_clear(hash); kfree(hash->buckets); kfree(hash); } static void __free_ftrace_hash_rcu(struct rcu_head *rcu) { struct ftrace_hash *hash; hash = container_of(rcu, struct ftrace_hash, rcu); free_ftrace_hash(hash); } static void free_ftrace_hash_rcu(struct ftrace_hash *hash) { if (!hash || hash == EMPTY_HASH) return; call_rcu(&hash->rcu, __free_ftrace_hash_rcu); } void ftrace_free_filter(struct ftrace_ops *ops) { ftrace_ops_init(ops); free_ftrace_hash(ops->func_hash->filter_hash); free_ftrace_hash(ops->func_hash->notrace_hash); } static struct ftrace_hash *alloc_ftrace_hash(int size_bits) { struct ftrace_hash *hash; int size; hash = kzalloc(sizeof(*hash), GFP_KERNEL); if (!hash) return NULL; size = 1 << size_bits; hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL); if (!hash->buckets) { kfree(hash); return NULL; } hash->size_bits = size_bits; return hash; } static int ftrace_add_mod(struct trace_array *tr, const char *func, const char *module, int enable) { struct ftrace_mod_load *ftrace_mod; struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace; ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL); if (!ftrace_mod) return -ENOMEM; ftrace_mod->func = kstrdup(func, GFP_KERNEL); ftrace_mod->module = kstrdup(module, GFP_KERNEL); ftrace_mod->enable = enable; if (!ftrace_mod->func || !ftrace_mod->module) goto out_free; list_add(&ftrace_mod->list, mod_head); return 0; out_free: free_ftrace_mod(ftrace_mod); return -ENOMEM; } static struct ftrace_hash * alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash) { struct ftrace_func_entry *entry; struct ftrace_hash *new_hash; int size; int ret; int i; new_hash = alloc_ftrace_hash(size_bits); if (!new_hash) return NULL; if (hash) new_hash->flags = hash->flags; /* Empty hash? */ if (ftrace_hash_empty(hash)) return new_hash; size = 1 << hash->size_bits; for (i = 0; i < size; i++) { hlist_for_each_entry(entry, &hash->buckets[i], hlist) { ret = add_hash_entry(new_hash, entry->ip); if (ret < 0) goto free_hash; } } FTRACE_WARN_ON(new_hash->count != hash->count); return new_hash; free_hash: free_ftrace_hash(new_hash); return NULL; } static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash); static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash); static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, struct ftrace_hash *new_hash); static struct ftrace_hash * __ftrace_hash_move(struct ftrace_hash *src) { struct ftrace_func_entry *entry; struct hlist_node *tn; struct hlist_head *hhd; struct ftrace_hash *new_hash; int size = src->count; int bits = 0; int i; /* * If the new source is empty, just return the empty_hash. */ if (ftrace_hash_empty(src)) return EMPTY_HASH; /* * Make the hash size about 1/2 the # found */ for (size /= 2; size; size >>= 1) bits++; /* Don't allocate too much */ if (bits > FTRACE_HASH_MAX_BITS) bits = FTRACE_HASH_MAX_BITS; new_hash = alloc_ftrace_hash(bits); if (!new_hash) return NULL; new_hash->flags = src->flags; size = 1 << src->size_bits; for (i = 0; i < size; i++) { hhd = &src->buckets[i]; hlist_for_each_entry_safe(entry, tn, hhd, hlist) { remove_hash_entry(src, entry); __add_hash_entry(new_hash, entry); } } return new_hash; } static int ftrace_hash_move(struct ftrace_ops *ops, int enable, struct ftrace_hash **dst, struct ftrace_hash *src) { struct ftrace_hash *new_hash; int ret; /* Reject setting notrace hash on IPMODIFY ftrace_ops */ if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable) return -EINVAL; new_hash = __ftrace_hash_move(src); if (!new_hash) return -ENOMEM; /* Make sure this can be applied if it is IPMODIFY ftrace_ops */ if (enable) { /* IPMODIFY should be updated only when filter_hash updating */ ret = ftrace_hash_ipmodify_update(ops, new_hash); if (ret < 0) { free_ftrace_hash(new_hash); return ret; } } /* * Remove the current set, update the hash and add * them back. */ ftrace_hash_rec_disable_modify(ops, enable); rcu_assign_pointer(*dst, new_hash); ftrace_hash_rec_enable_modify(ops, enable); return 0; } static bool hash_contains_ip(unsigned long ip, struct ftrace_ops_hash *hash) { /* * The function record is a match if it exists in the filter * hash and not in the notrace hash. Note, an emty hash is * considered a match for the filter hash, but an empty * notrace hash is considered not in the notrace hash. */ return (ftrace_hash_empty(hash->filter_hash) || __ftrace_lookup_ip(hash->filter_hash, ip)) && (ftrace_hash_empty(hash->notrace_hash) || !__ftrace_lookup_ip(hash->notrace_hash, ip)); } /* * Test the hashes for this ops to see if we want to call * the ops->func or not. * * It's a match if the ip is in the ops->filter_hash or * the filter_hash does not exist or is empty, * AND * the ip is not in the ops->notrace_hash. * * This needs to be called with preemption disabled as * the hashes are freed with call_rcu(). */ int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) { struct ftrace_ops_hash hash; int ret; #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS /* * There's a small race when adding ops that the ftrace handler * that wants regs, may be called without them. We can not * allow that handler to be called if regs is NULL. */ if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS)) return 0; #endif rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash); rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash); if (hash_contains_ip(ip, &hash)) ret = 1; else ret = 0; return ret; } /* * This is a double for. Do not use 'break' to break out of the loop, * you must use a goto. */ #define do_for_each_ftrace_rec(pg, rec) \ for (pg = ftrace_pages_start; pg; pg = pg->next) { \ int _____i; \ for (_____i = 0; _____i < pg->index; _____i++) { \ rec = &pg->records[_____i]; #define while_for_each_ftrace_rec() \ } \ } static int ftrace_cmp_recs(const void *a, const void *b) { const struct dyn_ftrace *key = a; const struct dyn_ftrace *rec = b; if (key->flags < rec->ip) return -1; if (key->ip >= rec->ip + MCOUNT_INSN_SIZE) return 1; return 0; } /** * ftrace_location_range - return the first address of a traced location * if it touches the given ip range * @start: start of range to search. * @end: end of range to search (inclusive). @end points to the last byte * to check. * * Returns rec->ip if the related ftrace location is a least partly within * the given address range. That is, the first address of the instruction * that is either a NOP or call to the function tracer. It checks the ftrace * internal tables to determine if the address belongs or not. */ unsigned long ftrace_location_range(unsigned long start, unsigned long end) { struct ftrace_page *pg; struct dyn_ftrace *rec; struct dyn_ftrace key; key.ip = start; key.flags = end; /* overload flags, as it is unsigned long */ for (pg = ftrace_pages_start; pg; pg = pg->next) { if (end < pg->records[0].ip || start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) continue; rec = bsearch(&key, pg->records, pg->index, sizeof(struct dyn_ftrace), ftrace_cmp_recs); if (rec) return rec->ip; } return 0; } /** * ftrace_location - return true if the ip giving is a traced location * @ip: the instruction pointer to check * * Returns rec->ip if @ip given is a pointer to a ftrace location. * That is, the instruction that is either a NOP or call to * the function tracer. It checks the ftrace internal tables to * determine if the address belongs or not. */ unsigned long ftrace_location(unsigned long ip) { return ftrace_location_range(ip, ip); } /** * ftrace_text_reserved - return true if range contains an ftrace location * @start: start of range to search * @end: end of range to search (inclusive). @end points to the last byte to check. * * Returns 1 if @start and @end contains a ftrace location. * That is, the instruction that is either a NOP or call to * the function tracer. It checks the ftrace internal tables to * determine if the address belongs or not. */ int ftrace_text_reserved(const void *start, const void *end) { unsigned long ret; ret = ftrace_location_range((unsigned long)start, (unsigned long)end); return (int)!!ret; } /* Test if ops registered to this rec needs regs */ static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) { struct ftrace_ops *ops; bool keep_regs = false; for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { /* pass rec in as regs to have non-NULL val */ if (ftrace_ops_test(ops, rec->ip, rec)) { if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { keep_regs = true; break; } } } return keep_regs; } static bool __ftrace_hash_rec_update(struct ftrace_ops *ops, int filter_hash, bool inc) { struct ftrace_hash *hash; struct ftrace_hash *other_hash; struct ftrace_page *pg; struct dyn_ftrace *rec; bool update = false; int count = 0; int all = false; /* Only update if the ops has been registered */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return false; /* * In the filter_hash case: * If the count is zero, we update all records. * Otherwise we just update the items in the hash. * * In the notrace_hash case: * We enable the update in the hash. * As disabling notrace means enabling the tracing, * and enabling notrace means disabling, the inc variable * gets inversed. */ if (filter_hash) { hash = ops->func_hash->filter_hash; other_hash = ops->func_hash->notrace_hash; if (ftrace_hash_empty(hash)) all = true; } else { inc = !inc; hash = ops->func_hash->notrace_hash; other_hash = ops->func_hash->filter_hash; /* * If the notrace hash has no items, * then there's nothing to do. */ if (ftrace_hash_empty(hash)) return false; } do_for_each_ftrace_rec(pg, rec) { int in_other_hash = 0; int in_hash = 0; int match = 0; if (rec->flags & FTRACE_FL_DISABLED) continue; if (all) { /* * Only the filter_hash affects all records. * Update if the record is not in the notrace hash. */ if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip)) match = 1; } else { in_hash = !!ftrace_lookup_ip(hash, rec->ip); in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip); /* * If filter_hash is set, we want to match all functions * that are in the hash but not in the other hash. * * If filter_hash is not set, then we are decrementing. * That means we match anything that is in the hash * and also in the other_hash. That is, we need to turn * off functions in the other hash because they are disabled * by this hash. */ if (filter_hash && in_hash && !in_other_hash) match = 1; else if (!filter_hash && in_hash && (in_other_hash || ftrace_hash_empty(other_hash))) match = 1; } if (!match) continue; if (inc) { rec->flags++; if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) return false; /* * If there's only a single callback registered to a * function, and the ops has a trampoline registered * for it, then we can call it directly. */ if (ftrace_rec_count(rec) == 1 && ops->trampoline) rec->flags |= FTRACE_FL_TRAMP; else /* * If we are adding another function callback * to this function, and the previous had a * custom trampoline in use, then we need to go * back to the default trampoline. */ rec->flags &= ~FTRACE_FL_TRAMP; /* * If any ops wants regs saved for this function * then all ops will get saved regs. */ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) rec->flags |= FTRACE_FL_REGS; } else { if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) return false; rec->flags--; /* * If the rec had REGS enabled and the ops that is * being removed had REGS set, then see if there is * still any ops for this record that wants regs. * If not, we can stop recording them. */ if (ftrace_rec_count(rec) > 0 && rec->flags & FTRACE_FL_REGS && ops->flags & FTRACE_OPS_FL_SAVE_REGS) { if (!test_rec_ops_needs_regs(rec)) rec->flags &= ~FTRACE_FL_REGS; } /* * If the rec had TRAMP enabled, then it needs to * be cleared. As TRAMP can only be enabled iff * there is only a single ops attached to it. * In otherwords, always disable it on decrementing. * In the future, we may set it if rec count is * decremented to one, and the ops that is left * has a trampoline. */ rec->flags &= ~FTRACE_FL_TRAMP; /* * flags will be cleared in ftrace_check_record() * if rec count is zero. */ } count++; /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */ update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE; /* Shortcut, if we handled all records, we are done. */ if (!all && count == hash->count) return update; } while_for_each_ftrace_rec(); return update; } static bool ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash) { return __ftrace_hash_rec_update(ops, filter_hash, 0); } static bool ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash) { return __ftrace_hash_rec_update(ops, filter_hash, 1); } static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops, int filter_hash, int inc) { struct ftrace_ops *op; __ftrace_hash_rec_update(ops, filter_hash, inc); if (ops->func_hash != &global_ops.local_hash) return; /* * If the ops shares the global_ops hash, then we need to update * all ops that are enabled and use this hash. */ do_for_each_ftrace_op(op, ftrace_ops_list) { /* Already done */ if (op == ops) continue; if (op->func_hash == &global_ops.local_hash) __ftrace_hash_rec_update(op, filter_hash, inc); } while_for_each_ftrace_op(op); } static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash) { ftrace_hash_rec_update_modify(ops, filter_hash, 0); } static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash) { ftrace_hash_rec_update_modify(ops, filter_hash, 1); } /* * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK * or no-needed to update, -EBUSY if it detects a conflict of the flag * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs. * Note that old_hash and new_hash has below meanings * - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected) * - If the hash is EMPTY_HASH, it hits nothing * - Anything else hits the recs which match the hash entries. */ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, struct ftrace_hash *old_hash, struct ftrace_hash *new_hash) { struct ftrace_page *pg; struct dyn_ftrace *rec, *end = NULL; int in_old, in_new; /* Only update if the ops has been registered */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return 0; if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY)) return 0; /* * Since the IPMODIFY is a very address sensitive action, we do not * allow ftrace_ops to set all functions to new hash. */ if (!new_hash || !old_hash) return -EINVAL; /* Update rec->flags */ do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_DISABLED) continue; /* We need to update only differences of filter_hash */ in_old = !!ftrace_lookup_ip(old_hash, rec->ip); in_new = !!ftrace_lookup_ip(new_hash, rec->ip); if (in_old == in_new) continue; if (in_new) { /* New entries must ensure no others are using it */ if (rec->flags & FTRACE_FL_IPMODIFY) goto rollback; rec->flags |= FTRACE_FL_IPMODIFY; } else /* Removed entry */ rec->flags &= ~FTRACE_FL_IPMODIFY; } while_for_each_ftrace_rec(); return 0; rollback: end = rec; /* Roll back what we did above */ do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_DISABLED) continue; if (rec == end) goto err_out; in_old = !!ftrace_lookup_ip(old_hash, rec->ip); in_new = !!ftrace_lookup_ip(new_hash, rec->ip); if (in_old == in_new) continue; if (in_new) rec->flags &= ~FTRACE_FL_IPMODIFY; else rec->flags |= FTRACE_FL_IPMODIFY; } while_for_each_ftrace_rec(); err_out: return -EBUSY; } static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops) { struct ftrace_hash *hash = ops->func_hash->filter_hash; if (ftrace_hash_empty(hash)) hash = NULL; return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash); } /* Disabling always succeeds */ static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops) { struct ftrace_hash *hash = ops->func_hash->filter_hash; if (ftrace_hash_empty(hash)) hash = NULL; __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH); } static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, struct ftrace_hash *new_hash) { struct ftrace_hash *old_hash = ops->func_hash->filter_hash; if (ftrace_hash_empty(old_hash)) old_hash = NULL; if (ftrace_hash_empty(new_hash)) new_hash = NULL; return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash); } static void print_ip_ins(const char *fmt, const unsigned char *p) { int i; printk(KERN_CONT "%s", fmt); for (i = 0; i < MCOUNT_INSN_SIZE; i++) printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); } static struct ftrace_ops * ftrace_find_tramp_ops_any(struct dyn_ftrace *rec); static struct ftrace_ops * ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops); enum ftrace_bug_type ftrace_bug_type; const void *ftrace_expected; static void print_bug_type(void) { switch (ftrace_bug_type) { case FTRACE_BUG_UNKNOWN: break; case FTRACE_BUG_INIT: pr_info("Initializing ftrace call sites\n"); break; case FTRACE_BUG_NOP: pr_info("Setting ftrace call site to NOP\n"); break; case FTRACE_BUG_CALL: pr_info("Setting ftrace call site to call ftrace function\n"); break; case FTRACE_BUG_UPDATE: pr_info("Updating ftrace call site to call a different ftrace function\n"); break; } } /** * ftrace_bug - report and shutdown function tracer * @failed: The failed type (EFAULT, EINVAL, EPERM) * @rec: The record that failed * * The arch code that enables or disables the function tracing * can call ftrace_bug() when it has detected a problem in * modifying the code. @failed should be one of either: * EFAULT - if the problem happens on reading the @ip address * EINVAL - if what is read at @ip is not what was expected * EPERM - if the problem happens on writting to the @ip address */ void ftrace_bug(int failed, struct dyn_ftrace *rec) { unsigned long ip = rec ? rec->ip : 0; switch (failed) { case -EFAULT: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on modifying "); print_ip_sym(ip); break; case -EINVAL: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace failed to modify "); print_ip_sym(ip); print_ip_ins(" actual: ", (unsigned char *)ip); pr_cont("\n"); if (ftrace_expected) { print_ip_ins(" expected: ", ftrace_expected); pr_cont("\n"); } break; case -EPERM: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on writing "); print_ip_sym(ip); break; default: FTRACE_WARN_ON_ONCE(1); pr_info("ftrace faulted on unknown error "); print_ip_sym(ip); } print_bug_type(); if (rec) { struct ftrace_ops *ops = NULL; pr_info("ftrace record flags: %lx\n", rec->flags); pr_cont(" (%ld)%s", ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_any(rec); if (ops) { do { pr_cont("\ttramp: %pS (%pS)", (void *)ops->trampoline, (void *)ops->func); ops = ftrace_find_tramp_ops_next(rec, ops); } while (ops); } else pr_cont("\ttramp: ERROR!"); } ip = ftrace_get_addr_curr(rec); pr_cont("\n expected tramp: %lx\n", ip); } } static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) { unsigned long flag = 0UL; ftrace_bug_type = FTRACE_BUG_UNKNOWN; if (rec->flags & FTRACE_FL_DISABLED) return FTRACE_UPDATE_IGNORE; /* * If we are updating calls: * * If the record has a ref count, then we need to enable it * because someone is using it. * * Otherwise we make sure its disabled. * * If we are disabling calls, then disable all records that * are enabled. */ if (enable && ftrace_rec_count(rec)) flag = FTRACE_FL_ENABLED; /* * If enabling and the REGS flag does not match the REGS_EN, or * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore * this record. Set flags to fail the compare against ENABLED. */ if (flag) { if (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)) flag |= FTRACE_FL_REGS; if (!(rec->flags & FTRACE_FL_TRAMP) != !(rec->flags & FTRACE_FL_TRAMP_EN)) flag |= FTRACE_FL_TRAMP; } /* If the state of this record hasn't changed, then do nothing */ if ((rec->flags & FTRACE_FL_ENABLED) == flag) return FTRACE_UPDATE_IGNORE; if (flag) { /* Save off if rec is being enabled (for return value) */ flag ^= rec->flags & FTRACE_FL_ENABLED; if (update) { rec->flags |= FTRACE_FL_ENABLED; if (flag & FTRACE_FL_REGS) { if (rec->flags & FTRACE_FL_REGS) rec->flags |= FTRACE_FL_REGS_EN; else rec->flags &= ~FTRACE_FL_REGS_EN; } if (flag & FTRACE_FL_TRAMP) { if (rec->flags & FTRACE_FL_TRAMP) rec->flags |= FTRACE_FL_TRAMP_EN; else rec->flags &= ~FTRACE_FL_TRAMP_EN; } } /* * If this record is being updated from a nop, then * return UPDATE_MAKE_CALL. * Otherwise, * return UPDATE_MODIFY_CALL to tell the caller to convert * from the save regs, to a non-save regs function or * vice versa, or from a trampoline call. */ if (flag & FTRACE_FL_ENABLED) { ftrace_bug_type = FTRACE_BUG_CALL; return FTRACE_UPDATE_MAKE_CALL; } ftrace_bug_type = FTRACE_BUG_UPDATE; return FTRACE_UPDATE_MODIFY_CALL; } if (update) { /* If there's no more users, clear all flags */ if (!ftrace_rec_count(rec)) rec->flags = 0; else /* * Just disable the record, but keep the ops TRAMP * and REGS states. The _EN flags must be disabled though. */ rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN | FTRACE_FL_REGS_EN); } ftrace_bug_type = FTRACE_BUG_NOP; return FTRACE_UPDATE_MAKE_NOP; } /** * ftrace_update_record, set a record that now is tracing or not * @rec: the record to update * @enable: set to 1 if the record is tracing, zero to force disable * * The records that represent all functions that can be traced need * to be updated when tracing has been enabled. */ int ftrace_update_record(struct dyn_ftrace *rec, int enable) { return ftrace_check_record(rec, enable, 1); } /** * ftrace_test_record, check if the record has been enabled or not * @rec: the record to test * @enable: set to 1 to check if enabled, 0 if it is disabled * * The arch code may need to test if a record is already set to * tracing to determine how to modify the function code that it * represents. */ int ftrace_test_record(struct dyn_ftrace *rec, int enable) { return ftrace_check_record(rec, enable, 0); } static struct ftrace_ops * ftrace_find_tramp_ops_any(struct dyn_ftrace *rec) { struct ftrace_ops *op; unsigned long ip = rec->ip; do_for_each_ftrace_op(op, ftrace_ops_list) { if (!op->trampoline) continue; if (hash_contains_ip(ip, op->func_hash)) return op; } while_for_each_ftrace_op(op); return NULL; } static struct ftrace_ops * ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *op) { unsigned long ip = rec->ip; while_for_each_ftrace_op(op) { if (!op->trampoline) continue; if (hash_contains_ip(ip, op->func_hash)) return op; } return NULL; } static struct ftrace_ops * ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec) { struct ftrace_ops *op; unsigned long ip = rec->ip; /* * Need to check removed ops first. * If they are being removed, and this rec has a tramp, * and this rec is in the ops list, then it would be the * one with the tramp. */ if (removed_ops) { if (hash_contains_ip(ip, &removed_ops->old_hash)) return removed_ops; } /* * Need to find the current trampoline for a rec. * Now, a trampoline is only attached to a rec if there * was a single 'ops' attached to it. But this can be called * when we are adding another op to the rec or removing the * current one. Thus, if the op is being added, we can * ignore it because it hasn't attached itself to the rec * yet. * * If an ops is being modified (hooking to different functions) * then we don't care about the new functions that are being * added, just the old ones (that are probably being removed). * * If we are adding an ops to a function that already is using * a trampoline, it needs to be removed (trampolines are only * for single ops connected), then an ops that is not being * modified also needs to be checked. */ do_for_each_ftrace_op(op, ftrace_ops_list) { if (!op->trampoline) continue; /* * If the ops is being added, it hasn't gotten to * the point to be removed from this tree yet. */ if (op->flags & FTRACE_OPS_FL_ADDING) continue; /* * If the ops is being modified and is in the old * hash, then it is probably being removed from this * function. */ if ((op->flags & FTRACE_OPS_FL_MODIFYING) && hash_contains_ip(ip, &op->old_hash)) return op; /* * If the ops is not being added or modified, and it's * in its normal filter hash, then this must be the one * we want! */ if (!(op->flags & FTRACE_OPS_FL_MODIFYING) && hash_contains_ip(ip, op->func_hash)) return op; } while_for_each_ftrace_op(op); return NULL; } static struct ftrace_ops * ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) { struct ftrace_ops *op; unsigned long ip = rec->ip; do_for_each_ftrace_op(op, ftrace_ops_list) { /* pass rec in as regs to have non-NULL val */ if (hash_contains_ip(ip, op->func_hash)) return op; } while_for_each_ftrace_op(op); return NULL; } /** * ftrace_get_addr_new - Get the call address to set to * @rec: The ftrace record descriptor * * If the record has the FTRACE_FL_REGS set, that means that it * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS * is not not set, then it wants to convert to the normal callback. * * Returns the address of the trampoline to set to */ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) { struct ftrace_ops *ops; /* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP) { ops = ftrace_find_tramp_ops_new(rec); if (FTRACE_WARN_ON(!ops || !ops->trampoline)) { pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n", (void *)rec->ip, (void *)rec->ip, rec->flags); /* Ftrace is shutting down, return anything */ return (unsigned long)FTRACE_ADDR; } return ops->trampoline; } if (rec->flags & FTRACE_FL_REGS) return (unsigned long)FTRACE_REGS_ADDR; else return (unsigned long)FTRACE_ADDR; } /** * ftrace_get_addr_curr - Get the call address that is already there * @rec: The ftrace record descriptor * * The FTRACE_FL_REGS_EN is set when the record already points to * a function that saves all the regs. Basically the '_EN' version * represents the current state of the function. * * Returns the address of the trampoline that is currently being called */ unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) { struct ftrace_ops *ops; /* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_curr(rec); if (FTRACE_WARN_ON(!ops)) { pr_warn("Bad trampoline accounting at: %p (%pS)\n", (void *)rec->ip, (void *)rec->ip); /* Ftrace is shutting down, return anything */ return (unsigned long)FTRACE_ADDR; } return ops->trampoline; } if (rec->flags & FTRACE_FL_REGS_EN) return (unsigned long)FTRACE_REGS_ADDR; else return (unsigned long)FTRACE_ADDR; } static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { unsigned long ftrace_old_addr; unsigned long ftrace_addr; int ret; ftrace_addr = ftrace_get_addr_new(rec); /* This needs to be done before we call ftrace_update_record */ ftrace_old_addr = ftrace_get_addr_curr(rec); ret = ftrace_update_record(rec, enable); ftrace_bug_type = FTRACE_BUG_UNKNOWN; switch (ret) { case FTRACE_UPDATE_IGNORE: return 0; case FTRACE_UPDATE_MAKE_CALL: ftrace_bug_type = FTRACE_BUG_CALL; return ftrace_make_call(rec, ftrace_addr); case FTRACE_UPDATE_MAKE_NOP: ftrace_bug_type = FTRACE_BUG_NOP; return ftrace_make_nop(NULL, rec, ftrace_old_addr); case FTRACE_UPDATE_MODIFY_CALL: ftrace_bug_type = FTRACE_BUG_UPDATE; return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr); } return -1; /* unknow ftrace bug */ } void __weak ftrace_replace_code(int mod_flags) { struct dyn_ftrace *rec; struct ftrace_page *pg; int enable = mod_flags & FTRACE_MODIFY_ENABLE_FL; int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL; int failed; if (unlikely(ftrace_disabled)) return; do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_DISABLED) continue; failed = __ftrace_replace_code(rec, enable); if (failed) { ftrace_bug(failed, rec); /* Stop processing */ return; } if (schedulable) cond_resched(); } while_for_each_ftrace_rec(); } struct ftrace_rec_iter { struct ftrace_page *pg; int index; }; /** * ftrace_rec_iter_start, start up iterating over traced functions * * Returns an iterator handle that is used to iterate over all * the records that represent address locations where functions * are traced. * * May return NULL if no records are available. */ struct ftrace_rec_iter *ftrace_rec_iter_start(void) { /* * We only use a single iterator. * Protected by the ftrace_lock mutex. */ static struct ftrace_rec_iter ftrace_rec_iter; struct ftrace_rec_iter *iter = &ftrace_rec_iter; iter->pg = ftrace_pages_start; iter->index = 0; /* Could have empty pages */ while (iter->pg && !iter->pg->index) iter->pg = iter->pg->next; if (!iter->pg) return NULL; return iter; } /** * ftrace_rec_iter_next, get the next record to process. * @iter: The handle to the iterator. * * Returns the next iterator after the given iterator @iter. */ struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter) { iter->index++; if (iter->index >= iter->pg->index) { iter->pg = iter->pg->next; iter->index = 0; /* Could have empty pages */ while (iter->pg && !iter->pg->index) iter->pg = iter->pg->next; } if (!iter->pg) return NULL; return iter; } /** * ftrace_rec_iter_record, get the record at the iterator location * @iter: The current iterator location * * Returns the record that the current @iter is at. */ struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter) { return &iter->pg->records[iter->index]; } static int ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec) { int ret; if (unlikely(ftrace_disabled)) return 0; ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR); if (ret) { ftrace_bug_type = FTRACE_BUG_INIT; ftrace_bug(ret, rec); return 0; } return 1; } /* * archs can override this function if they must do something * before the modifying code is performed. */ int __weak ftrace_arch_code_modify_prepare(void) { return 0; } /* * archs can override this function if they must do something * after the modifying code is performed. */ int __weak ftrace_arch_code_modify_post_process(void) { return 0; } void ftrace_modify_all_code(int command) { int update = command & FTRACE_UPDATE_TRACE_FUNC; int mod_flags = 0; int err = 0; if (command & FTRACE_MAY_SLEEP) mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL; /* * If the ftrace_caller calls a ftrace_ops func directly, * we need to make sure that it only traces functions it * expects to trace. When doing the switch of functions, * we need to update to the ftrace_ops_list_func first * before the transition between old and new calls are set, * as the ftrace_ops_list_func will check the ops hashes * to make sure the ops are having the right functions * traced. */ if (update) { err = ftrace_update_ftrace_func(ftrace_ops_list_func); if (FTRACE_WARN_ON(err)) return; } if (command & FTRACE_UPDATE_CALLS) ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL); else if (command & FTRACE_DISABLE_CALLS) ftrace_replace_code(mod_flags); if (update && ftrace_trace_function != ftrace_ops_list_func) { function_trace_op = set_function_trace_op; smp_wmb(); /* If irqs are disabled, we are in stop machine */ if (!irqs_disabled()) smp_call_function(ftrace_sync_ipi, NULL, 1); err = ftrace_update_ftrace_func(ftrace_trace_function); if (FTRACE_WARN_ON(err)) return; } if (command & FTRACE_START_FUNC_RET) err = ftrace_enable_ftrace_graph_caller(); else if (command & FTRACE_STOP_FUNC_RET) err = ftrace_disable_ftrace_graph_caller(); FTRACE_WARN_ON(err); } static int __ftrace_modify_code(void *data) { int *command = data; ftrace_modify_all_code(*command); return 0; } /** * ftrace_run_stop_machine, go back to the stop machine method * @command: The command to tell ftrace what to do * * If an arch needs to fall back to the stop machine method, the * it can call this function. */ void ftrace_run_stop_machine(int command) { stop_machine(__ftrace_modify_code, &command, NULL); } /** * arch_ftrace_update_code, modify the code to trace or not trace * @command: The command that needs to be done * * Archs can override this function if it does not need to * run stop_machine() to modify code. */ void __weak arch_ftrace_update_code(int command) { ftrace_run_stop_machine(command); } static void ftrace_run_update_code(int command) { int ret; ret = ftrace_arch_code_modify_prepare(); FTRACE_WARN_ON(ret); if (ret) return; /* * By default we use stop_machine() to modify the code. * But archs can do what ever they want as long as it * is safe. The stop_machine() is the safest, but also * produces the most overhead. */ arch_ftrace_update_code(command); ret = ftrace_arch_code_modify_post_process(); FTRACE_WARN_ON(ret); } static void ftrace_run_modify_code(struct ftrace_ops *ops, int command, struct ftrace_ops_hash *old_hash) { ops->flags |= FTRACE_OPS_FL_MODIFYING; ops->old_hash.filter_hash = old_hash->filter_hash; ops->old_hash.notrace_hash = old_hash->notrace_hash; ftrace_run_update_code(command); ops->old_hash.filter_hash = NULL; ops->old_hash.notrace_hash = NULL; ops->flags &= ~FTRACE_OPS_FL_MODIFYING; } static ftrace_func_t saved_ftrace_func; static int ftrace_start_up; void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops) { } static void ftrace_startup_enable(int command) { if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; command |= FTRACE_UPDATE_TRACE_FUNC; } if (!command || !ftrace_enabled) return; ftrace_run_update_code(command); } static void ftrace_startup_all(int command) { update_all_ops = true; ftrace_startup_enable(command); update_all_ops = false; } int ftrace_startup(struct ftrace_ops *ops, int command) { int ret; if (unlikely(ftrace_disabled)) return -ENODEV; ret = __register_ftrace_function(ops); if (ret) return ret; ftrace_start_up++; /* * Note that ftrace probes uses this to start up * and modify functions it will probe. But we still * set the ADDING flag for modification, as probes * do not have trampolines. If they add them in the * future, then the probes will need to distinguish * between adding and updating probes. */ ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING; ret = ftrace_hash_ipmodify_enable(ops); if (ret < 0) { /* Rollback registration process */ __unregister_ftrace_function(ops); ftrace_start_up--; ops->flags &= ~FTRACE_OPS_FL_ENABLED; return ret; } if (ftrace_hash_rec_enable(ops, 1)) command |= FTRACE_UPDATE_CALLS; ftrace_startup_enable(command); ops->flags &= ~FTRACE_OPS_FL_ADDING; return 0; } int ftrace_shutdown(struct ftrace_ops *ops, int command) { int ret; if (unlikely(ftrace_disabled)) return -ENODEV; ret = __unregister_ftrace_function(ops); if (ret) return ret; ftrace_start_up--; /* * Just warn in case of unbalance, no need to kill ftrace, it's not * critical but the ftrace_call callers may be never nopped again after * further ftrace uses. */ WARN_ON_ONCE(ftrace_start_up < 0); /* Disabling ipmodify never fails */ ftrace_hash_ipmodify_disable(ops); if (ftrace_hash_rec_disable(ops, 1)) command |= FTRACE_UPDATE_CALLS; ops->flags &= ~FTRACE_OPS_FL_ENABLED; if (saved_ftrace_func != ftrace_trace_function) { saved_ftrace_func = ftrace_trace_function; command |= FTRACE_UPDATE_TRACE_FUNC; } if (!command || !ftrace_enabled) { /* * If these are dynamic or per_cpu ops, they still * need their data freed. Since, function tracing is * not currently active, we can just free them * without synchronizing all CPUs. */ if (ops->flags & FTRACE_OPS_FL_DYNAMIC) goto free_ops; return 0; } /* * If the ops uses a trampoline, then it needs to be * tested first on update. */ ops->flags |= FTRACE_OPS_FL_REMOVING; removed_ops = ops; /* The trampoline logic checks the old hashes */ ops->old_hash.filter_hash = ops->func_hash->filter_hash; ops->old_hash.notrace_hash = ops->func_hash->notrace_hash; ftrace_run_update_code(command); /* * If there's no more ops registered with ftrace, run a * sanity check to make sure all rec flags are cleared. */ if (rcu_dereference_protected(ftrace_ops_list, lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) { struct ftrace_page *pg; struct dyn_ftrace *rec; do_for_each_ftrace_rec(pg, rec) { if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED)) pr_warn(" %pS flags:%lx\n", (void *)rec->ip, rec->flags); } while_for_each_ftrace_rec(); } ops->old_hash.filter_hash = NULL; ops->old_hash.notrace_hash = NULL; removed_ops = NULL; ops->flags &= ~FTRACE_OPS_FL_REMOVING; /* * Dynamic ops may be freed, we must make sure that all * callers are done before leaving this function. * The same goes for freeing the per_cpu data of the per_cpu * ops. */ if (ops->flags & FTRACE_OPS_FL_DYNAMIC) { /* * We need to do a hard force of sched synchronization. * This is because we use preempt_disable() to do RCU, but * the function tracers can be called where RCU is not watching * (like before user_exit()). We can not rely on the RCU * infrastructure to do the synchronization, thus we must do it * ourselves. */ schedule_on_each_cpu(ftrace_sync); /* * When the kernel is preeptive, tasks can be preempted * while on a ftrace trampoline. Just scheduling a task on * a CPU is not good enough to flush them. Calling * synchornize_rcu_tasks() will wait for those tasks to * execute and either schedule voluntarily or enter user space. */ if (IS_ENABLED(CONFIG_PREEMPT)) synchronize_rcu_tasks(); free_ops: arch_ftrace_trampoline_free(ops); } return 0; } static void ftrace_startup_sysctl(void) { int command; if (unlikely(ftrace_disabled)) return; /* Force update next time */ saved_ftrace_func = NULL; /* ftrace_start_up is true if we want ftrace running */ if (ftrace_start_up) { command = FTRACE_UPDATE_CALLS; if (ftrace_graph_active) command |= FTRACE_START_FUNC_RET; ftrace_startup_enable(command); } } static void ftrace_shutdown_sysctl(void) { int command; if (unlikely(ftrace_disabled)) return; /* ftrace_start_up is true if ftrace is running */ if (ftrace_start_up) { command = FTRACE_DISABLE_CALLS; if (ftrace_graph_active) command |= FTRACE_STOP_FUNC_RET; ftrace_run_update_code(command); } } static u64 ftrace_update_time; unsigned long ftrace_update_tot_cnt; static inline int ops_traces_mod(struct ftrace_ops *ops) { /* * Filter_hash being empty will default to trace module. * But notrace hash requires a test of individual module functions. */ return ftrace_hash_empty(ops->func_hash->filter_hash) && ftrace_hash_empty(ops->func_hash->notrace_hash); } /* * Check if the current ops references the record. * * If the ops traces all functions, then it was already accounted for. * If the ops does not trace the current record function, skip it. * If the ops ignores the function via notrace filter, skip it. */ static inline bool ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec) { /* If ops isn't enabled, ignore it */ if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return false; /* If ops traces all then it includes this function */ if (ops_traces_mod(ops)) return true; /* The function must be in the filter */ if (!ftrace_hash_empty(ops->func_hash->filter_hash) && !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip)) return false; /* If in notrace hash, we ignore it too */ if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip)) return false; return true; } static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs) { struct ftrace_page *pg; struct dyn_ftrace *p; u64 start, stop; unsigned long update_cnt = 0; unsigned long rec_flags = 0; int i; start = ftrace_now(raw_smp_processor_id()); /* * When a module is loaded, this function is called to convert * the calls to mcount in its text to nops, and also to create * an entry in the ftrace data. Now, if ftrace is activated * after this call, but before the module sets its text to * read-only, the modification of enabling ftrace can fail if * the read-only is done while ftrace is converting the calls. * To prevent this, the module's records are set as disabled * and will be enabled after the call to set the module's text * to read-only. */ if (mod) rec_flags |= FTRACE_FL_DISABLED; for (pg = new_pgs; pg; pg = pg->next) { for (i = 0; i < pg->index; i++) { /* If something went wrong, bail without enabling anything */ if (unlikely(ftrace_disabled)) return -1; p = &pg->records[i]; p->flags = rec_flags; #ifndef CC_USING_NOP_MCOUNT /* * Do the initial record conversion from mcount jump * to the NOP instructions. */ if (!ftrace_code_disable(mod, p)) break; #endif update_cnt++; } } stop = ftrace_now(raw_smp_processor_id()); ftrace_update_time = stop - start; ftrace_update_tot_cnt += update_cnt; return 0; } static int ftrace_allocate_records(struct ftrace_page *pg, int count) { int order; int cnt; if (WARN_ON(!count)) return -EINVAL; order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE)); /* * We want to fill as much as possible. No more than a page * may be empty. */ while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE) order--; again: pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order); if (!pg->records) { /* if we can't allocate this size, try something smaller */ if (!order) return -ENOMEM; order >>= 1; goto again; } cnt = (PAGE_SIZE << order) / ENTRY_SIZE; pg->size = cnt; if (cnt > count) cnt = count; return cnt; } static struct ftrace_page * ftrace_allocate_pages(unsigned long num_to_init) { struct ftrace_page *start_pg; struct ftrace_page *pg; int order; int cnt; if (!num_to_init) return 0; start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL); if (!pg) return NULL; /* * Try to allocate as much as possible in one continues * location that fills in all of the space. We want to * waste as little space as possible. */ for (;;) { cnt = ftrace_allocate_records(pg, num_to_init); if (cnt < 0) goto free_pages; num_to_init -= cnt; if (!num_to_init) break; pg->next = kzalloc(sizeof(*pg), GFP_KERNEL); if (!pg->next) goto free_pages; pg = pg->next; } return start_pg; free_pages: pg = start_pg; while (pg) { order = get_count_order(pg->size / ENTRIES_PER_PAGE); free_pages((unsigned long)pg->records, order); start_pg = pg->next; kfree(pg); pg = start_pg; } pr_info("ftrace: FAILED to allocate memory for functions\n"); return NULL; } #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ struct ftrace_iterator { loff_t pos; loff_t func_pos; loff_t mod_pos; struct ftrace_page *pg; struct dyn_ftrace *func; struct ftrace_func_probe *probe; struct ftrace_func_entry *probe_entry; struct trace_parser parser; struct ftrace_hash *hash; struct ftrace_ops *ops; struct trace_array *tr; struct list_head *mod_list; int pidx; int idx; unsigned flags; }; static void * t_probe_next(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct trace_array *tr = iter->ops->private; struct list_head *func_probes; struct ftrace_hash *hash; struct list_head *next; struct hlist_node *hnd = NULL; struct hlist_head *hhd; int size; (*pos)++; iter->pos = *pos; if (!tr) return NULL; func_probes = &tr->func_probes; if (list_empty(func_probes)) return NULL; if (!iter->probe) { next = func_probes->next; iter->probe = list_entry(next, struct ftrace_func_probe, list); } if (iter->probe_entry) hnd = &iter->probe_entry->hlist; hash = iter->probe->ops.func_hash->filter_hash; size = 1 << hash->size_bits; retry: if (iter->pidx >= size) { if (iter->probe->list.next == func_probes) return NULL; next = iter->probe->list.next; iter->probe = list_entry(next, struct ftrace_func_probe, list); hash = iter->probe->ops.func_hash->filter_hash; size = 1 << hash->size_bits; iter->pidx = 0; } hhd = &hash->buckets[iter->pidx]; if (hlist_empty(hhd)) { iter->pidx++; hnd = NULL; goto retry; } if (!hnd) hnd = hhd->first; else { hnd = hnd->next; if (!hnd) { iter->pidx++; goto retry; } } if (WARN_ON_ONCE(!hnd)) return NULL; iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist); return iter; } static void *t_probe_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; loff_t l; if (!(iter->flags & FTRACE_ITER_DO_PROBES)) return NULL; if (iter->mod_pos > *pos) return NULL; iter->probe = NULL; iter->probe_entry = NULL; iter->pidx = 0; for (l = 0; l <= (*pos - iter->mod_pos); ) { p = t_probe_next(m, &l); if (!p) break; } if (!p) return NULL; /* Only set this if we have an item */ iter->flags |= FTRACE_ITER_PROBE; return iter; } static int t_probe_show(struct seq_file *m, struct ftrace_iterator *iter) { struct ftrace_func_entry *probe_entry; struct ftrace_probe_ops *probe_ops; struct ftrace_func_probe *probe; probe = iter->probe; probe_entry = iter->probe_entry; if (WARN_ON_ONCE(!probe || !probe_entry)) return -EIO; probe_ops = probe->probe_ops; if (probe_ops->print) return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data); seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip, (void *)probe_ops->func); return 0; } static void * t_mod_next(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct trace_array *tr = iter->tr; (*pos)++; iter->pos = *pos; iter->mod_list = iter->mod_list->next; if (iter->mod_list == &tr->mod_trace || iter->mod_list == &tr->mod_notrace) { iter->flags &= ~FTRACE_ITER_MOD; return NULL; } iter->mod_pos = *pos; return iter; } static void *t_mod_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; loff_t l; if (iter->func_pos > *pos) return NULL; iter->mod_pos = iter->func_pos; /* probes are only available if tr is set */ if (!iter->tr) return NULL; for (l = 0; l <= (*pos - iter->func_pos); ) { p = t_mod_next(m, &l); if (!p) break; } if (!p) { iter->flags &= ~FTRACE_ITER_MOD; return t_probe_start(m, pos); } /* Only set this if we have an item */ iter->flags |= FTRACE_ITER_MOD; return iter; } static int t_mod_show(struct seq_file *m, struct ftrace_iterator *iter) { struct ftrace_mod_load *ftrace_mod; struct trace_array *tr = iter->tr; if (WARN_ON_ONCE(!iter->mod_list) || iter->mod_list == &tr->mod_trace || iter->mod_list == &tr->mod_notrace) return -EIO; ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list); if (ftrace_mod->func) seq_printf(m, "%s", ftrace_mod->func); else seq_putc(m, '*'); seq_printf(m, ":mod:%s\n", ftrace_mod->module); return 0; } static void * t_func_next(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct dyn_ftrace *rec = NULL; (*pos)++; retry: if (iter->idx >= iter->pg->index) { if (iter->pg->next) { iter->pg = iter->pg->next; iter->idx = 0; goto retry; } } else { rec = &iter->pg->records[iter->idx++]; if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && !ftrace_lookup_ip(iter->hash, rec->ip)) || ((iter->flags & FTRACE_ITER_ENABLED) && !(rec->flags & FTRACE_FL_ENABLED))) { rec = NULL; goto retry; } } if (!rec) return NULL; iter->pos = iter->func_pos = *pos; iter->func = rec; return iter; } static void * t_next(struct seq_file *m, void *v, loff_t *pos) { struct ftrace_iterator *iter = m->private; loff_t l = *pos; /* t_probe_start() must use original pos */ void *ret; if (unlikely(ftrace_disabled)) return NULL; if (iter->flags & FTRACE_ITER_PROBE) return t_probe_next(m, pos); if (iter->flags & FTRACE_ITER_MOD) return t_mod_next(m, pos); if (iter->flags & FTRACE_ITER_PRINTALL) { /* next must increment pos, and t_probe_start does not */ (*pos)++; return t_mod_start(m, &l); } ret = t_func_next(m, pos); if (!ret) return t_mod_start(m, &l); return ret; } static void reset_iter_read(struct ftrace_iterator *iter) { iter->pos = 0; iter->func_pos = 0; iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD); } static void *t_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; loff_t l; mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) return NULL; /* * If an lseek was done, then reset and start from beginning. */ if (*pos < iter->pos) reset_iter_read(iter); /* * For set_ftrace_filter reading, if we have the filter * off, we can short cut and just print out that all * functions are enabled. */ if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) && ftrace_hash_empty(iter->hash)) { iter->func_pos = 1; /* Account for the message */ if (*pos > 0) return t_mod_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; /* reset in case of seek/pread */ iter->flags &= ~FTRACE_ITER_PROBE; return iter; } if (iter->flags & FTRACE_ITER_MOD) return t_mod_start(m, pos); /* * Unfortunately, we need to restart at ftrace_pages_start * every time we let go of the ftrace_mutex. This is because * those pointers can change without the lock. */ iter->pg = ftrace_pages_start; iter->idx = 0; for (l = 0; l <= *pos; ) { p = t_func_next(m, &l); if (!p) break; } if (!p) return t_mod_start(m, pos); return iter; } static void t_stop(struct seq_file *m, void *p) { mutex_unlock(&ftrace_lock); } void * __weak arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) { return NULL; } static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops, struct dyn_ftrace *rec) { void *ptr; ptr = arch_ftrace_trampoline_func(ops, rec); if (ptr) seq_printf(m, " ->%pS", ptr); } static int t_show(struct seq_file *m, void *v) { struct ftrace_iterator *iter = m->private; struct dyn_ftrace *rec; if (iter->flags & FTRACE_ITER_PROBE) return t_probe_show(m, iter); if (iter->flags & FTRACE_ITER_MOD) return t_mod_show(m, iter); if (iter->flags & FTRACE_ITER_PRINTALL) { if (iter->flags & FTRACE_ITER_NOTRACE) seq_puts(m, "#### no functions disabled ####\n"); else seq_puts(m, "#### all functions enabled ####\n"); return 0; } rec = iter->func; if (!rec) return 0; seq_printf(m, "%ps", (void *)rec->ip); if (iter->flags & FTRACE_ITER_ENABLED) { struct ftrace_ops *ops; seq_printf(m, " (%ld)%s%s", ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : " ", rec->flags & FTRACE_FL_IPMODIFY ? " I" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_any(rec); if (ops) { do { seq_printf(m, "\ttramp: %pS (%pS)", (void *)ops->trampoline, (void *)ops->func); add_trampoline_func(m, ops, rec); ops = ftrace_find_tramp_ops_next(rec, ops); } while (ops); } else seq_puts(m, "\ttramp: ERROR!"); } else { add_trampoline_func(m, NULL, rec); } } seq_putc(m, '\n'); return 0; } static const struct seq_operations show_ftrace_seq_ops = { .start = t_start, .next = t_next, .stop = t_stop, .show = t_show, }; static int ftrace_avail_open(struct inode *inode, struct file *file) { struct ftrace_iterator *iter; if (unlikely(ftrace_disabled)) return -ENODEV; iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); if (!iter) return -ENOMEM; iter->pg = ftrace_pages_start; iter->ops = &global_ops; return 0; } static int ftrace_enabled_open(struct inode *inode, struct file *file) { struct ftrace_iterator *iter; iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); if (!iter) return -ENOMEM; iter->pg = ftrace_pages_start; iter->flags = FTRACE_ITER_ENABLED; iter->ops = &global_ops; return 0; } /** * ftrace_regex_open - initialize function tracer filter files * @ops: The ftrace_ops that hold the hash filters * @flag: The type of filter to process * @inode: The inode, usually passed in to your open routine * @file: The file, usually passed in to your open routine * * ftrace_regex_open() initializes the filter files for the * @ops. Depending on @flag it may process the filter hash or * the notrace hash of @ops. With this called from the open * routine, you can use ftrace_filter_write() for the write * routine if @flag has FTRACE_ITER_FILTER set, or * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set. * tracing_lseek() should be used as the lseek routine, and * release must call ftrace_regex_release(). */ int ftrace_regex_open(struct ftrace_ops *ops, int flag, struct inode *inode, struct file *file) { struct ftrace_iterator *iter; struct ftrace_hash *hash; struct list_head *mod_head; struct trace_array *tr = ops->private; int ret = 0; ftrace_ops_init(ops); if (unlikely(ftrace_disabled)) return -ENODEV; iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return -ENOMEM; if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) { kfree(iter); return -ENOMEM; } iter->ops = ops; iter->flags = flag; iter->tr = tr; mutex_lock(&ops->func_hash->regex_lock); if (flag & FTRACE_ITER_NOTRACE) { hash = ops->func_hash->notrace_hash; mod_head = tr ? &tr->mod_notrace : NULL; } else { hash = ops->func_hash->filter_hash; mod_head = tr ? &tr->mod_trace : NULL; } iter->mod_list = mod_head; if (file->f_mode & FMODE_WRITE) { const int size_bits = FTRACE_HASH_DEFAULT_BITS; if (file->f_flags & O_TRUNC) { iter->hash = alloc_ftrace_hash(size_bits); clear_ftrace_mod_list(mod_head); } else { iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash); } if (!iter->hash) { trace_parser_put(&iter->parser); kfree(iter); ret = -ENOMEM; goto out_unlock; } } else iter->hash = hash; if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start; ret = seq_open(file, &show_ftrace_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = iter; } else { /* Failed */ free_ftrace_hash(iter->hash); trace_parser_put(&iter->parser); kfree(iter); } } else file->private_data = iter; out_unlock: mutex_unlock(&ops->func_hash->regex_lock); return ret; } static int ftrace_filter_open(struct inode *inode, struct file *file) { struct ftrace_ops *ops = inode->i_private; return ftrace_regex_open(ops, FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES, inode, file); } static int ftrace_notrace_open(struct inode *inode, struct file *file) { struct ftrace_ops *ops = inode->i_private; return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE, inode, file); } /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */ struct ftrace_glob { char *search; unsigned len; int type; }; /* * If symbols in an architecture don't correspond exactly to the user-visible * name of what they represent, it is possible to define this function to * perform the necessary adjustments. */ char * __weak arch_ftrace_match_adjust(char *str, const char *search) { return str; } static int ftrace_match(char *str, struct ftrace_glob *g) { int matched = 0; int slen; str = arch_ftrace_match_adjust(str, g->search); switch (g->type) { case MATCH_FULL: if (strcmp(str, g->search) == 0) matched = 1; break; case MATCH_FRONT_ONLY: if (strncmp(str, g->search, g->len) == 0) matched = 1; break; case MATCH_MIDDLE_ONLY: if (strstr(str, g->search)) matched = 1; break; case MATCH_END_ONLY: slen = strlen(str); if (slen >= g->len && memcmp(str + slen - g->len, g->search, g->len) == 0) matched = 1; break; case MATCH_GLOB: if (glob_match(g->search, str)) matched = 1; break; } return matched; } static int enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter) { struct ftrace_func_entry *entry; int ret = 0; entry = ftrace_lookup_ip(hash, rec->ip); if (clear_filter) { /* Do nothing if it doesn't exist */ if (!entry) return 0; free_hash_entry(hash, entry); } else { /* Do nothing if it exists */ if (entry) return 0; ret = add_hash_entry(hash, rec->ip); } return ret; } static int ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g, struct ftrace_glob *mod_g, int exclude_mod) { char str[KSYM_SYMBOL_LEN]; char *modname; kallsyms_lookup(rec->ip, NULL, NULL, &modname, str); if (mod_g) { int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0; /* blank module name to match all modules */ if (!mod_g->len) { /* blank module globbing: modname xor exclude_mod */ if (!exclude_mod != !modname) goto func_match; return 0; } /* * exclude_mod is set to trace everything but the given * module. If it is set and the module matches, then * return 0. If it is not set, and the module doesn't match * also return 0. Otherwise, check the function to see if * that matches. */ if (!mod_matches == !exclude_mod) return 0; func_match: /* blank search means to match all funcs in the mod */ if (!func_g->len) return 1; } return ftrace_match(str, func_g); } static int match_records(struct ftrace_hash *hash, char *func, int len, char *mod) { struct ftrace_page *pg; struct dyn_ftrace *rec; struct ftrace_glob func_g = { .type = MATCH_FULL }; struct ftrace_glob mod_g = { .type = MATCH_FULL }; struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL; int exclude_mod = 0; int found = 0; int ret; int clear_filter = 0; if (func) { func_g.type = filter_parse_regex(func, len, &func_g.search, &clear_filter); func_g.len = strlen(func_g.search); } if (mod) { mod_g.type = filter_parse_regex(mod, strlen(mod), &mod_g.search, &exclude_mod); mod_g.len = strlen(mod_g.search); } mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) goto out_unlock; do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_DISABLED) continue; if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) { ret = enter_record(hash, rec, clear_filter); if (ret < 0) { found = ret; goto out_unlock; } found = 1; } } while_for_each_ftrace_rec(); out_unlock: mutex_unlock(&ftrace_lock); return found; } static int ftrace_match_records(struct ftrace_hash *hash, char *buff, int len) { return match_records(hash, buff, len, NULL); } static void ftrace_ops_update_code(struct ftrace_ops *ops, struct ftrace_ops_hash *old_hash) { struct ftrace_ops *op; if (!ftrace_enabled) return; if (ops->flags & FTRACE_OPS_FL_ENABLED) { ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash); return; } /* * If this is the shared global_ops filter, then we need to * check if there is another ops that shares it, is enabled. * If so, we still need to run the modify code. */ if (ops->func_hash != &global_ops.local_hash) return; do_for_each_ftrace_op(op, ftrace_ops_list) { if (op->func_hash == &global_ops.local_hash && op->flags & FTRACE_OPS_FL_ENABLED) { ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash); /* Only need to do this once */ return; } } while_for_each_ftrace_op(op); } static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops, struct ftrace_hash **orig_hash, struct ftrace_hash *hash, int enable) { struct ftrace_ops_hash old_hash_ops; struct ftrace_hash *old_hash; int ret; old_hash = *orig_hash; old_hash_ops.filter_hash = ops->func_hash->filter_hash; old_hash_ops.notrace_hash = ops->func_hash->notrace_hash; ret = ftrace_hash_move(ops, enable, orig_hash, hash); if (!ret) { ftrace_ops_update_code(ops, &old_hash_ops); free_ftrace_hash_rcu(old_hash); } return ret; } static bool module_exists(const char *module) { /* All modules have the symbol __this_module */ const char this_mod[] = "__this_module"; char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2]; unsigned long val; int n; n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod); if (n > sizeof(modname) - 1) return false; val = module_kallsyms_lookup_name(modname); return val != 0; } static int cache_mod(struct trace_array *tr, const char *func, char *module, int enable) { struct ftrace_mod_load *ftrace_mod, *n; struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace; int ret; mutex_lock(&ftrace_lock); /* We do not cache inverse filters */ if (func[0] == '!') { func++; ret = -EINVAL; /* Look to remove this hash */ list_for_each_entry_safe(ftrace_mod, n, head, list) { if (strcmp(ftrace_mod->module, module) != 0) continue; /* no func matches all */ if (strcmp(func, "*") == 0 || (ftrace_mod->func && strcmp(ftrace_mod->func, func) == 0)) { ret = 0; free_ftrace_mod(ftrace_mod); continue; } } goto out; } ret = -EINVAL; /* We only care about modules that have not been loaded yet */ if (module_exists(module)) goto out; /* Save this string off, and execute it when the module is loaded */ ret = ftrace_add_mod(tr, func, module, enable); out: mutex_unlock(&ftrace_lock); return ret; } static int ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, int reset, int enable); #ifdef CONFIG_MODULES static void process_mod_list(struct list_head *head, struct ftrace_ops *ops, char *mod, bool enable) { struct ftrace_mod_load *ftrace_mod, *n; struct ftrace_hash **orig_hash, *new_hash; LIST_HEAD(process_mods); char *func; int ret; mutex_lock(&ops->func_hash->regex_lock); if (enable) orig_hash = &ops->func_hash->filter_hash; else orig_hash = &ops->func_hash->notrace_hash; new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); if (!new_hash) goto out; /* warn? */ mutex_lock(&ftrace_lock); list_for_each_entry_safe(ftrace_mod, n, head, list) { if (strcmp(ftrace_mod->module, mod) != 0) continue; if (ftrace_mod->func) func = kstrdup(ftrace_mod->func, GFP_KERNEL); else func = kstrdup("*", GFP_KERNEL); if (!func) /* warn? */ continue; list_del(&ftrace_mod->list); list_add(&ftrace_mod->list, &process_mods); /* Use the newly allocated func, as it may be "*" */ kfree(ftrace_mod->func); ftrace_mod->func = func; } mutex_unlock(&ftrace_lock); list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) { func = ftrace_mod->func; /* Grabs ftrace_lock, which is why we have this extra step */ match_records(new_hash, func, strlen(func), mod); free_ftrace_mod(ftrace_mod); } if (enable && list_empty(head)) new_hash->flags &= ~FTRACE_HASH_FL_MOD; mutex_lock(&ftrace_lock); ret = ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable); mutex_unlock(&ftrace_lock); out: mutex_unlock(&ops->func_hash->regex_lock); free_ftrace_hash(new_hash); } static void process_cached_mods(const char *mod_name) { struct trace_array *tr; char *mod; mod = kstrdup(mod_name, GFP_KERNEL); if (!mod) return; mutex_lock(&trace_types_lock); list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (!list_empty(&tr->mod_trace)) process_mod_list(&tr->mod_trace, tr->ops, mod, true); if (!list_empty(&tr->mod_notrace)) process_mod_list(&tr->mod_notrace, tr->ops, mod, false); } mutex_unlock(&trace_types_lock); kfree(mod); } #endif /* * We register the module command as a template to show others how * to register the a command as well. */ static int ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash, char *func_orig, char *cmd, char *module, int enable) { char *func; int ret; /* match_records() modifies func, and we need the original */ func = kstrdup(func_orig, GFP_KERNEL); if (!func) return -ENOMEM; /* * cmd == 'mod' because we only registered this func * for the 'mod' ftrace_func_command. * But if you register one func with multiple commands, * you can tell which command was used by the cmd * parameter. */ ret = match_records(hash, func, strlen(func), module); kfree(func); if (!ret) return cache_mod(tr, func_orig, module, enable); if (ret < 0) return ret; return 0; } static struct ftrace_func_command ftrace_mod_cmd = { .name = "mod", .func = ftrace_mod_callback, }; static int __init ftrace_mod_cmd_init(void) { return register_ftrace_command(&ftrace_mod_cmd); } core_initcall(ftrace_mod_cmd_init); static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *pt_regs) { struct ftrace_probe_ops *probe_ops; struct ftrace_func_probe *probe; probe = container_of(op, struct ftrace_func_probe, ops); probe_ops = probe->probe_ops; /* * Disable preemption for these calls to prevent a RCU grace * period. This syncs the hash iteration and freeing of items * on the hash. rcu_read_lock is too dangerous here. */ preempt_disable_notrace(); probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data); preempt_enable_notrace(); } struct ftrace_func_map { struct ftrace_func_entry entry; void *data; }; struct ftrace_func_mapper { struct ftrace_hash hash; }; /** * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper * * Returns a ftrace_func_mapper descriptor that can be used to map ips to data. */ struct ftrace_func_mapper *allocate_ftrace_func_mapper(void) { struct ftrace_hash *hash; /* * The mapper is simply a ftrace_hash, but since the entries * in the hash are not ftrace_func_entry type, we define it * as a separate structure. */ hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); return (struct ftrace_func_mapper *)hash; } /** * ftrace_func_mapper_find_ip - Find some data mapped to an ip * @mapper: The mapper that has the ip maps * @ip: the instruction pointer to find the data for * * Returns the data mapped to @ip if found otherwise NULL. The return * is actually the address of the mapper data pointer. The address is * returned for use cases where the data is no bigger than a long, and * the user can use the data pointer as its data instead of having to * allocate more memory for the reference. */ void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper, unsigned long ip) { struct ftrace_func_entry *entry; struct ftrace_func_map *map; entry = ftrace_lookup_ip(&mapper->hash, ip); if (!entry) return NULL; map = (struct ftrace_func_map *)entry; return &map->data; } /** * ftrace_func_mapper_add_ip - Map some data to an ip * @mapper: The mapper that has the ip maps * @ip: The instruction pointer address to map @data to * @data: The data to map to @ip * * Returns 0 on succes otherwise an error. */ int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper, unsigned long ip, void *data) { struct ftrace_func_entry *entry; struct ftrace_func_map *map; entry = ftrace_lookup_ip(&mapper->hash, ip); if (entry) return -EBUSY; map = kmalloc(sizeof(*map), GFP_KERNEL); if (!map) return -ENOMEM; map->entry.ip = ip; map->data = data; __add_hash_entry(&mapper->hash, &map->entry); return 0; } /** * ftrace_func_mapper_remove_ip - Remove an ip from the mapping * @mapper: The mapper that has the ip maps * @ip: The instruction pointer address to remove the data from * * Returns the data if it is found, otherwise NULL. * Note, if the data pointer is used as the data itself, (see * ftrace_func_mapper_find_ip(), then the return value may be meaningless, * if the data pointer was set to zero. */ void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper, unsigned long ip) { struct ftrace_func_entry *entry; struct ftrace_func_map *map; void *data; entry = ftrace_lookup_ip(&mapper->hash, ip); if (!entry) return NULL; map = (struct ftrace_func_map *)entry; data = map->data; remove_hash_entry(&mapper->hash, entry); kfree(entry); return data; } /** * free_ftrace_func_mapper - free a mapping of ips and data * @mapper: The mapper that has the ip maps * @free_func: A function to be called on each data item. * * This is used to free the function mapper. The @free_func is optional * and can be used if the data needs to be freed as well. */ void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper, ftrace_mapper_func free_func) { struct ftrace_func_entry *entry; struct ftrace_func_map *map; struct hlist_head *hhd; int size = 1 << mapper->hash.size_bits; int i; if (free_func && mapper->hash.count) { for (i = 0; i < size; i++) { hhd = &mapper->hash.buckets[i]; hlist_for_each_entry(entry, hhd, hlist) { map = (struct ftrace_func_map *)entry; free_func(map); } } } free_ftrace_hash(&mapper->hash); } static void release_probe(struct ftrace_func_probe *probe) { struct ftrace_probe_ops *probe_ops; mutex_lock(&ftrace_lock); WARN_ON(probe->ref <= 0); /* Subtract the ref that was used to protect this instance */ probe->ref--; if (!probe->ref) { probe_ops = probe->probe_ops; /* * Sending zero as ip tells probe_ops to free * the probe->data itself */ if (probe_ops->free) probe_ops->free(probe_ops, probe->tr, 0, probe->data); list_del(&probe->list); kfree(probe); } mutex_unlock(&ftrace_lock); } static void acquire_probe_locked(struct ftrace_func_probe *probe) { /* * Add one ref to keep it from being freed when releasing the * ftrace_lock mutex. */ probe->ref++; } int register_ftrace_function_probe(char *glob, struct trace_array *tr, struct ftrace_probe_ops *probe_ops, void *data) { struct ftrace_func_entry *entry; struct ftrace_func_probe *probe; struct ftrace_hash **orig_hash; struct ftrace_hash *old_hash; struct ftrace_hash *hash; int count = 0; int size; int ret; int i; if (WARN_ON(!tr)) return -EINVAL; /* We do not support '!' for function probes */ if (WARN_ON(glob[0] == '!')) return -EINVAL; mutex_lock(&ftrace_lock); /* Check if the probe_ops is already registered */ list_for_each_entry(probe, &tr->func_probes, list) { if (probe->probe_ops == probe_ops) break; } if (&probe->list == &tr->func_probes) { probe = kzalloc(sizeof(*probe), GFP_KERNEL); if (!probe) { mutex_unlock(&ftrace_lock); return -ENOMEM; } probe->probe_ops = probe_ops; probe->ops.func = function_trace_probe_call; probe->tr = tr; ftrace_ops_init(&probe->ops); list_add(&probe->list, &tr->func_probes); } acquire_probe_locked(probe); mutex_unlock(&ftrace_lock); mutex_lock(&probe->ops.func_hash->regex_lock); orig_hash = &probe->ops.func_hash->filter_hash; old_hash = *orig_hash; hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); ret = ftrace_match_records(hash, glob, strlen(glob)); /* Nothing found? */ if (!ret) ret = -EINVAL; if (ret < 0) goto out; size = 1 << hash->size_bits; for (i = 0; i < size; i++) { hlist_for_each_entry(entry, &hash->buckets[i], hlist) { if (ftrace_lookup_ip(old_hash, entry->ip)) continue; /* * The caller might want to do something special * for each function we find. We call the callback * to give the caller an opportunity to do so. */ if (probe_ops->init) { ret = probe_ops->init(probe_ops, tr, entry->ip, data, &probe->data); if (ret < 0) { if (probe_ops->free && count) probe_ops->free(probe_ops, tr, 0, probe->data); probe->data = NULL; goto out; } } count++; } } mutex_lock(&ftrace_lock); if (!count) { /* Nothing was added? */ ret = -EINVAL; goto out_unlock; } ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, hash, 1); if (ret < 0) goto err_unlock; /* One ref for each new function traced */ probe->ref += count; if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED)) ret = ftrace_startup(&probe->ops, 0); out_unlock: mutex_unlock(&ftrace_lock); if (!ret) ret = count; out: mutex_unlock(&probe->ops.func_hash->regex_lock); free_ftrace_hash(hash); release_probe(probe); return ret; err_unlock: if (!probe_ops->free || !count) goto out_unlock; /* Failed to do the move, need to call the free functions */ for (i = 0; i < size; i++) { hlist_for_each_entry(entry, &hash->buckets[i], hlist) { if (ftrace_lookup_ip(old_hash, entry->ip)) continue; probe_ops->free(probe_ops, tr, entry->ip, probe->data); } } goto out_unlock; } int unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr, struct ftrace_probe_ops *probe_ops) { struct ftrace_ops_hash old_hash_ops; struct ftrace_func_entry *entry; struct ftrace_func_probe *probe; struct ftrace_glob func_g; struct ftrace_hash **orig_hash; struct ftrace_hash *old_hash; struct ftrace_hash *hash = NULL; struct hlist_node *tmp; struct hlist_head hhd; char str[KSYM_SYMBOL_LEN]; int count = 0; int i, ret = -ENODEV; int size; if (!glob || !strlen(glob) || !strcmp(glob, "*")) func_g.search = NULL; else { int not; func_g.type = filter_parse_regex(glob, strlen(glob), &func_g.search, ¬); func_g.len = strlen(func_g.search); /* we do not support '!' for function probes */ if (WARN_ON(not)) return -EINVAL; } mutex_lock(&ftrace_lock); /* Check if the probe_ops is already registered */ list_for_each_entry(probe, &tr->func_probes, list) { if (probe->probe_ops == probe_ops) break; } if (&probe->list == &tr->func_probes) goto err_unlock_ftrace; ret = -EINVAL; if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED)) goto err_unlock_ftrace; acquire_probe_locked(probe); mutex_unlock(&ftrace_lock); mutex_lock(&probe->ops.func_hash->regex_lock); orig_hash = &probe->ops.func_hash->filter_hash; old_hash = *orig_hash; if (ftrace_hash_empty(old_hash)) goto out_unlock; old_hash_ops.filter_hash = old_hash; /* Probes only have filters */ old_hash_ops.notrace_hash = NULL; ret = -ENOMEM; hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash); if (!hash) goto out_unlock; INIT_HLIST_HEAD(&hhd); size = 1 << hash->size_bits; for (i = 0; i < size; i++) { hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) { if (func_g.search) { kallsyms_lookup(entry->ip, NULL, NULL, NULL, str); if (!ftrace_match(str, &func_g)) continue; } count++; remove_hash_entry(hash, entry); hlist_add_head(&entry->hlist, &hhd); } } /* Nothing found? */ if (!count) { ret = -EINVAL; goto out_unlock; } mutex_lock(&ftrace_lock); WARN_ON(probe->ref < count); probe->ref -= count; if (ftrace_hash_empty(hash)) ftrace_shutdown(&probe->ops, 0); ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash, hash, 1); /* still need to update the function call sites */ if (ftrace_enabled && !ftrace_hash_empty(hash)) ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS, &old_hash_ops); synchronize_rcu(); hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) { hlist_del(&entry->hlist); if (probe_ops->free) probe_ops->free(probe_ops, tr, entry->ip, probe->data); kfree(entry); } mutex_unlock(&ftrace_lock); out_unlock: mutex_unlock(&probe->ops.func_hash->regex_lock); free_ftrace_hash(hash); release_probe(probe); return ret; err_unlock_ftrace: mutex_unlock(&ftrace_lock); return ret; } void clear_ftrace_function_probes(struct trace_array *tr) { struct ftrace_func_probe *probe, *n; list_for_each_entry_safe(probe, n, &tr->func_probes, list) unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops); } static LIST_HEAD(ftrace_commands); static DEFINE_MUTEX(ftrace_cmd_mutex); /* * Currently we only register ftrace commands from __init, so mark this * __init too. */ __init int register_ftrace_command(struct ftrace_func_command *cmd) { struct ftrace_func_command *p; int ret = 0; mutex_lock(&ftrace_cmd_mutex); list_for_each_entry(p, &ftrace_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = -EBUSY; goto out_unlock; } } list_add(&cmd->list, &ftrace_commands); out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } /* * Currently we only unregister ftrace commands from __init, so mark * this __init too. */ __init int unregister_ftrace_command(struct ftrace_func_command *cmd) { struct ftrace_func_command *p, *n; int ret = -ENODEV; mutex_lock(&ftrace_cmd_mutex); list_for_each_entry_safe(p, n, &ftrace_commands, list) { if (strcmp(cmd->name, p->name) == 0) { ret = 0; list_del_init(&p->list); goto out_unlock; } } out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } static int ftrace_process_regex(struct ftrace_iterator *iter, char *buff, int len, int enable) { struct ftrace_hash *hash = iter->hash; struct trace_array *tr = iter->ops->private; char *func, *command, *next = buff; struct ftrace_func_command *p; int ret = -EINVAL; func = strsep(&next, ":"); if (!next) { ret = ftrace_match_records(hash, func, len); if (!ret) ret = -EINVAL; if (ret < 0) return ret; return 0; } /* command found */ command = strsep(&next, ":"); mutex_lock(&ftrace_cmd_mutex); list_for_each_entry(p, &ftrace_commands, list) { if (strcmp(p->name, command) == 0) { ret = p->func(tr, hash, func, command, next, enable); goto out_unlock; } } out_unlock: mutex_unlock(&ftrace_cmd_mutex); return ret; } static ssize_t ftrace_regex_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos, int enable) { struct ftrace_iterator *iter; struct trace_parser *parser; ssize_t ret, read; if (!cnt) return 0; if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; iter = m->private; } else iter = file->private_data; if (unlikely(ftrace_disabled)) return -ENODEV; /* iter->hash is a local copy, so we don't need regex_lock */ parser = &iter->parser; read = trace_get_user(parser, ubuf, cnt, ppos); if (read >= 0 && trace_parser_loaded(parser) && !trace_parser_cont(parser)) { ret = ftrace_process_regex(iter, parser->buffer, parser->idx, enable); trace_parser_clear(parser); if (ret < 0) goto out; } ret = read; out: return ret; } ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { return ftrace_regex_write(file, ubuf, cnt, ppos, 1); } ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { return ftrace_regex_write(file, ubuf, cnt, ppos, 0); } static int ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove) { struct ftrace_func_entry *entry; if (!ftrace_location(ip)) return -EINVAL; if (remove) { entry = ftrace_lookup_ip(hash, ip); if (!entry) return -ENOENT; free_hash_entry(hash, entry); return 0; } return add_hash_entry(hash, ip); } static int ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, unsigned long ip, int remove, int reset, int enable) { struct ftrace_hash **orig_hash; struct ftrace_hash *hash; int ret; if (unlikely(ftrace_disabled)) return -ENODEV; mutex_lock(&ops->func_hash->regex_lock); if (enable) orig_hash = &ops->func_hash->filter_hash; else orig_hash = &ops->func_hash->notrace_hash; if (reset) hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); else hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); if (!hash) { ret = -ENOMEM; goto out_regex_unlock; } if (buf && !ftrace_match_records(hash, buf, len)) { ret = -EINVAL; goto out_regex_unlock; } if (ip) { ret = ftrace_match_addr(hash, ip, remove); if (ret < 0) goto out_regex_unlock; } mutex_lock(&ftrace_lock); ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable); mutex_unlock(&ftrace_lock); out_regex_unlock: mutex_unlock(&ops->func_hash->regex_lock); free_ftrace_hash(hash); return ret; } static int ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove, int reset, int enable) { return ftrace_set_hash(ops, 0, 0, ip, remove, reset, enable); } /** * ftrace_set_filter_ip - set a function to filter on in ftrace by address * @ops - the ops to set the filter with * @ip - the address to add to or remove from the filter. * @remove - non zero to remove the ip from the filter * @reset - non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled * If @ip is NULL, it failes to update filter. */ int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, int remove, int reset) { ftrace_ops_init(ops); return ftrace_set_addr(ops, ip, remove, reset, 1); } EXPORT_SYMBOL_GPL(ftrace_set_filter_ip); /** * ftrace_ops_set_global_filter - setup ops to use global filters * @ops - the ops which will use the global filters * * ftrace users who need global function trace filtering should call this. * It can set the global filter only if ops were not initialized before. */ void ftrace_ops_set_global_filter(struct ftrace_ops *ops) { if (ops->flags & FTRACE_OPS_FL_INITIALIZED) return; ftrace_ops_init(ops); ops->func_hash = &global_ops.local_hash; } EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter); static int ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, int reset, int enable) { return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable); } /** * ftrace_set_filter - set a function to filter on in ftrace * @ops - the ops to set the filter with * @buf - the string that holds the function filter text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. */ int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, int len, int reset) { ftrace_ops_init(ops); return ftrace_set_regex(ops, buf, len, reset, 1); } EXPORT_SYMBOL_GPL(ftrace_set_filter); /** * ftrace_set_notrace - set a function to not trace in ftrace * @ops - the ops to set the notrace filter with * @buf - the string that holds the function notrace text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. */ int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, int len, int reset) { ftrace_ops_init(ops); return ftrace_set_regex(ops, buf, len, reset, 0); } EXPORT_SYMBOL_GPL(ftrace_set_notrace); /** * ftrace_set_global_filter - set a function to filter on with global tracers * @buf - the string that holds the function filter text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. */ void ftrace_set_global_filter(unsigned char *buf, int len, int reset) { ftrace_set_regex(&global_ops, buf, len, reset, 1); } EXPORT_SYMBOL_GPL(ftrace_set_global_filter); /** * ftrace_set_global_notrace - set a function to not trace with global tracers * @buf - the string that holds the function notrace text. * @len - the length of the string. * @reset - non zero to reset all filters before applying this filter. * * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. */ void ftrace_set_global_notrace(unsigned char *buf, int len, int reset) { ftrace_set_regex(&global_ops, buf, len, reset, 0); } EXPORT_SYMBOL_GPL(ftrace_set_global_notrace); /* * command line interface to allow users to set filters on boot up. */ #define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata; /* Used by function selftest to not test if filter is set */ bool ftrace_filter_param __initdata; static int __init set_ftrace_notrace(char *str) { ftrace_filter_param = true; strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_notrace=", set_ftrace_notrace); static int __init set_ftrace_filter(char *str) { ftrace_filter_param = true; strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_filter=", set_ftrace_filter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer); static int __init set_graph_function(char *str) { strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_filter=", set_graph_function); static int __init set_graph_notrace_function(char *str) { strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE); return 1; } __setup("ftrace_graph_notrace=", set_graph_notrace_function); static int __init set_graph_max_depth_function(char *str) { if (!str) return 0; fgraph_max_depth = simple_strtoul(str, NULL, 0); return 1; } __setup("ftrace_graph_max_depth=", set_graph_max_depth_function); static void __init set_ftrace_early_graph(char *buf, int enable) { int ret; char *func; struct ftrace_hash *hash; hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); if (WARN_ON(!hash)) return; while (buf) { func = strsep(&buf, ","); /* we allow only one expression at a time */ ret = ftrace_graph_set_hash(hash, func); if (ret) printk(KERN_DEBUG "ftrace: function %s not " "traceable\n", func); } if (enable) ftrace_graph_hash = hash; else ftrace_graph_notrace_hash = hash; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ void __init ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable) { char *func; ftrace_ops_init(ops); while (buf) { func = strsep(&buf, ","); ftrace_set_regex(ops, func, strlen(func), 0, enable); } } static void __init set_ftrace_early_filters(void) { if (ftrace_filter_buf[0]) ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1); if (ftrace_notrace_buf[0]) ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0); #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (ftrace_graph_buf[0]) set_ftrace_early_graph(ftrace_graph_buf, 1); if (ftrace_graph_notrace_buf[0]) set_ftrace_early_graph(ftrace_graph_notrace_buf, 0); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ } int ftrace_regex_release(struct inode *inode, struct file *file) { struct seq_file *m = (struct seq_file *)file->private_data; struct ftrace_iterator *iter; struct ftrace_hash **orig_hash; struct trace_parser *parser; int filter_hash; int ret; if (file->f_mode & FMODE_READ) { iter = m->private; seq_release(inode, file); } else iter = file->private_data; parser = &iter->parser; if (trace_parser_loaded(parser)) { ftrace_match_records(iter->hash, parser->buffer, parser->idx); } trace_parser_put(parser); mutex_lock(&iter->ops->func_hash->regex_lock); if (file->f_mode & FMODE_WRITE) { filter_hash = !!(iter->flags & FTRACE_ITER_FILTER); if (filter_hash) { orig_hash = &iter->ops->func_hash->filter_hash; if (iter->tr && !list_empty(&iter->tr->mod_trace)) iter->hash->flags |= FTRACE_HASH_FL_MOD; } else orig_hash = &iter->ops->func_hash->notrace_hash; mutex_lock(&ftrace_lock); ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash, iter->hash, filter_hash); mutex_unlock(&ftrace_lock); } else { /* For read only, the hash is the ops hash */ iter->hash = NULL; } mutex_unlock(&iter->ops->func_hash->regex_lock); free_ftrace_hash(iter->hash); kfree(iter); return 0; } static const struct file_operations ftrace_avail_fops = { .open = ftrace_avail_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static const struct file_operations ftrace_enabled_fops = { .open = ftrace_enabled_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, .llseek = tracing_lseek, .release = ftrace_regex_release, }; static const struct file_operations ftrace_notrace_fops = { .open = ftrace_notrace_open, .read = seq_read, .write = ftrace_notrace_write, .llseek = tracing_lseek, .release = ftrace_regex_release, }; #ifdef CONFIG_FUNCTION_GRAPH_TRACER static DEFINE_MUTEX(graph_lock); struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH; struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; enum graph_filter_type { GRAPH_FILTER_NOTRACE = 0, GRAPH_FILTER_FUNCTION, }; #define FTRACE_GRAPH_EMPTY ((void *)1) struct ftrace_graph_data { struct ftrace_hash *hash; struct ftrace_func_entry *entry; int idx; /* for hash table iteration */ enum graph_filter_type type; struct ftrace_hash *new_hash; const struct seq_operations *seq_ops; struct trace_parser parser; }; static void * __g_next(struct seq_file *m, loff_t *pos) { struct ftrace_graph_data *fgd = m->private; struct ftrace_func_entry *entry = fgd->entry; struct hlist_head *head; int i, idx = fgd->idx; if (*pos >= fgd->hash->count) return NULL; if (entry) { hlist_for_each_entry_continue(entry, hlist) { fgd->entry = entry; return entry; } idx++; } for (i = idx; i < 1 << fgd->hash->size_bits; i++) { head = &fgd->hash->buckets[i]; hlist_for_each_entry(entry, head, hlist) { fgd->entry = entry; fgd->idx = i; return entry; } } return NULL; } static void * g_next(struct seq_file *m, void *v, loff_t *pos) { (*pos)++; return __g_next(m, pos); } static void *g_start(struct seq_file *m, loff_t *pos) { struct ftrace_graph_data *fgd = m->private; mutex_lock(&graph_lock); if (fgd->type == GRAPH_FILTER_FUNCTION) fgd->hash = rcu_dereference_protected(ftrace_graph_hash, lockdep_is_held(&graph_lock)); else fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, lockdep_is_held(&graph_lock)); /* Nothing, tell g_show to print all functions are enabled */ if (ftrace_hash_empty(fgd->hash) && !*pos) return FTRACE_GRAPH_EMPTY; fgd->idx = 0; fgd->entry = NULL; return __g_next(m, pos); } static void g_stop(struct seq_file *m, void *p) { mutex_unlock(&graph_lock); } static int g_show(struct seq_file *m, void *v) { struct ftrace_func_entry *entry = v; if (!entry) return 0; if (entry == FTRACE_GRAPH_EMPTY) { struct ftrace_graph_data *fgd = m->private; if (fgd->type == GRAPH_FILTER_FUNCTION) seq_puts(m, "#### all functions enabled ####\n"); else seq_puts(m, "#### no functions disabled ####\n"); return 0; } seq_printf(m, "%ps\n", (void *)entry->ip); return 0; } static const struct seq_operations ftrace_graph_seq_ops = { .start = g_start, .next = g_next, .stop = g_stop, .show = g_show, }; static int __ftrace_graph_open(struct inode *inode, struct file *file, struct ftrace_graph_data *fgd) { int ret = 0; struct ftrace_hash *new_hash = NULL; if (file->f_mode & FMODE_WRITE) { const int size_bits = FTRACE_HASH_DEFAULT_BITS; if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX)) return -ENOMEM; if (file->f_flags & O_TRUNC) new_hash = alloc_ftrace_hash(size_bits); else new_hash = alloc_and_copy_ftrace_hash(size_bits, fgd->hash); if (!new_hash) { ret = -ENOMEM; goto out; } } if (file->f_mode & FMODE_READ) { ret = seq_open(file, &ftrace_graph_seq_ops); if (!ret) { struct seq_file *m = file->private_data; m->private = fgd; } else { /* Failed */ free_ftrace_hash(new_hash); new_hash = NULL; } } else file->private_data = fgd; out: if (ret < 0 && file->f_mode & FMODE_WRITE) trace_parser_put(&fgd->parser); fgd->new_hash = new_hash; /* * All uses of fgd->hash must be taken with the graph_lock * held. The graph_lock is going to be released, so force * fgd->hash to be reinitialized when it is taken again. */ fgd->hash = NULL; return ret; } static int ftrace_graph_open(struct inode *inode, struct file *file) { struct ftrace_graph_data *fgd; int ret; if (unlikely(ftrace_disabled)) return -ENODEV; fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); if (fgd == NULL) return -ENOMEM; mutex_lock(&graph_lock); fgd->hash = rcu_dereference_protected(ftrace_graph_hash, lockdep_is_held(&graph_lock)); fgd->type = GRAPH_FILTER_FUNCTION; fgd->seq_ops = &ftrace_graph_seq_ops; ret = __ftrace_graph_open(inode, file, fgd); if (ret < 0) kfree(fgd); mutex_unlock(&graph_lock); return ret; } static int ftrace_graph_notrace_open(struct inode *inode, struct file *file) { struct ftrace_graph_data *fgd; int ret; if (unlikely(ftrace_disabled)) return -ENODEV; fgd = kmalloc(sizeof(*fgd), GFP_KERNEL); if (fgd == NULL) return -ENOMEM; mutex_lock(&graph_lock); fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash, lockdep_is_held(&graph_lock)); fgd->type = GRAPH_FILTER_NOTRACE; fgd->seq_ops = &ftrace_graph_seq_ops; ret = __ftrace_graph_open(inode, file, fgd); if (ret < 0) kfree(fgd); mutex_unlock(&graph_lock); return ret; } static int ftrace_graph_release(struct inode *inode, struct file *file) { struct ftrace_graph_data *fgd; struct ftrace_hash *old_hash, *new_hash; struct trace_parser *parser; int ret = 0; if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; fgd = m->private; seq_release(inode, file); } else { fgd = file->private_data; } if (file->f_mode & FMODE_WRITE) { parser = &fgd->parser; if (trace_parser_loaded((parser))) { ret = ftrace_graph_set_hash(fgd->new_hash, parser->buffer); } trace_parser_put(parser); new_hash = __ftrace_hash_move(fgd->new_hash); if (!new_hash) { ret = -ENOMEM; goto out; } mutex_lock(&graph_lock); if (fgd->type == GRAPH_FILTER_FUNCTION) { old_hash = rcu_dereference_protected(ftrace_graph_hash, lockdep_is_held(&graph_lock)); rcu_assign_pointer(ftrace_graph_hash, new_hash); } else { old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, lockdep_is_held(&graph_lock)); rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash); } mutex_unlock(&graph_lock); /* Wait till all users are no longer using the old hash */ synchronize_rcu(); free_ftrace_hash(old_hash); } out: free_ftrace_hash(fgd->new_hash); kfree(fgd); return ret; } static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer) { struct ftrace_glob func_g; struct dyn_ftrace *rec; struct ftrace_page *pg; struct ftrace_func_entry *entry; int fail = 1; int not; /* decode regex */ func_g.type = filter_parse_regex(buffer, strlen(buffer), &func_g.search, ¬); func_g.len = strlen(func_g.search); mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) { mutex_unlock(&ftrace_lock); return -ENODEV; } do_for_each_ftrace_rec(pg, rec) { if (rec->flags & FTRACE_FL_DISABLED) continue; if (ftrace_match_record(rec, &func_g, NULL, 0)) { entry = ftrace_lookup_ip(hash, rec->ip); if (!not) { fail = 0; if (entry) continue; if (add_hash_entry(hash, rec->ip) < 0) goto out; } else { if (entry) { free_hash_entry(hash, entry); fail = 0; } } } } while_for_each_ftrace_rec(); out: mutex_unlock(&ftrace_lock); if (fail) return -EINVAL; return 0; } static ssize_t ftrace_graph_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { ssize_t read, ret = 0; struct ftrace_graph_data *fgd = file->private_data; struct trace_parser *parser; if (!cnt) return 0; /* Read mode uses seq functions */ if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; fgd = m->private; } parser = &fgd->parser; read = trace_get_user(parser, ubuf, cnt, ppos); if (read >= 0 && trace_parser_loaded(parser) && !trace_parser_cont(parser)) { ret = ftrace_graph_set_hash(fgd->new_hash, parser->buffer); trace_parser_clear(parser); } if (!ret) ret = read; return ret; } static const struct file_operations ftrace_graph_fops = { .open = ftrace_graph_open, .read = seq_read, .write = ftrace_graph_write, .llseek = tracing_lseek, .release = ftrace_graph_release, }; static const struct file_operations ftrace_graph_notrace_fops = { .open = ftrace_graph_notrace_open, .read = seq_read, .write = ftrace_graph_write, .llseek = tracing_lseek, .release = ftrace_graph_release, }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ void ftrace_create_filter_files(struct ftrace_ops *ops, struct dentry *parent) { trace_create_file("set_ftrace_filter", 0644, parent, ops, &ftrace_filter_fops); trace_create_file("set_ftrace_notrace", 0644, parent, ops, &ftrace_notrace_fops); } /* * The name "destroy_filter_files" is really a misnomer. Although * in the future, it may actualy delete the files, but this is * really intended to make sure the ops passed in are disabled * and that when this function returns, the caller is free to * free the ops. * * The "destroy" name is only to match the "create" name that this * should be paired with. */ void ftrace_destroy_filter_files(struct ftrace_ops *ops) { mutex_lock(&ftrace_lock); if (ops->flags & FTRACE_OPS_FL_ENABLED) ftrace_shutdown(ops, 0); ops->flags |= FTRACE_OPS_FL_DELETED; ftrace_free_filter(ops); mutex_unlock(&ftrace_lock); } static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { trace_create_file("available_filter_functions", 0444, d_tracer, NULL, &ftrace_avail_fops); trace_create_file("enabled_functions", 0444, d_tracer, NULL, &ftrace_enabled_fops); ftrace_create_filter_files(&global_ops, d_tracer); #ifdef CONFIG_FUNCTION_GRAPH_TRACER trace_create_file("set_graph_function", 0644, d_tracer, NULL, &ftrace_graph_fops); trace_create_file("set_graph_notrace", 0644, d_tracer, NULL, &ftrace_graph_notrace_fops); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ return 0; } static int ftrace_cmp_ips(const void *a, const void *b) { const unsigned long *ipa = a; const unsigned long *ipb = b; if (*ipa > *ipb) return 1; if (*ipa < *ipb) return -1; return 0; } static int ftrace_process_locs(struct module *mod, unsigned long *start, unsigned long *end) { struct ftrace_page *start_pg; struct ftrace_page *pg; struct dyn_ftrace *rec; unsigned long count; unsigned long *p; unsigned long addr; unsigned long flags = 0; /* Shut up gcc */ int ret = -ENOMEM; count = end - start; if (!count) return 0; sort(start, count, sizeof(*start), ftrace_cmp_ips, NULL); start_pg = ftrace_allocate_pages(count); if (!start_pg) return -ENOMEM; mutex_lock(&ftrace_lock); /* * Core and each module needs their own pages, as * modules will free them when they are removed. * Force a new page to be allocated for modules. */ if (!mod) { WARN_ON(ftrace_pages || ftrace_pages_start); /* First initialization */ ftrace_pages = ftrace_pages_start = start_pg; } else { if (!ftrace_pages) goto out; if (WARN_ON(ftrace_pages->next)) { /* Hmm, we have free pages? */ while (ftrace_pages->next) ftrace_pages = ftrace_pages->next; } ftrace_pages->next = start_pg; } p = start; pg = start_pg; while (p < end) { addr = ftrace_call_adjust(*p++); /* * Some architecture linkers will pad between * the different mcount_loc sections of different * object files to satisfy alignments. * Skip any NULL pointers. */ if (!addr) continue; if (pg->index == pg->size) { /* We should have allocated enough */ if (WARN_ON(!pg->next)) break; pg = pg->next; } rec = &pg->records[pg->index++]; rec->ip = addr; } /* We should have used all pages */ WARN_ON(pg->next); /* Assign the last page to ftrace_pages */ ftrace_pages = pg; /* * We only need to disable interrupts on start up * because we are modifying code that an interrupt * may execute, and the modification is not atomic. * But for modules, nothing runs the code we modify * until we are finished with it, and there's no * reason to cause large interrupt latencies while we do it. */ if (!mod) local_irq_save(flags); ftrace_update_code(mod, start_pg); if (!mod) local_irq_restore(flags); ret = 0; out: mutex_unlock(&ftrace_lock); return ret; } struct ftrace_mod_func { struct list_head list; char *name; unsigned long ip; unsigned int size; }; struct ftrace_mod_map { struct rcu_head rcu; struct list_head list; struct module *mod; unsigned long start_addr; unsigned long end_addr; struct list_head funcs; unsigned int num_funcs; }; #ifdef CONFIG_MODULES #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next) static LIST_HEAD(ftrace_mod_maps); static int referenced_filters(struct dyn_ftrace *rec) { struct ftrace_ops *ops; int cnt = 0; for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { if (ops_references_rec(ops, rec)) cnt++; } return cnt; } static void clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash) { struct ftrace_func_entry *entry; struct dyn_ftrace *rec; int i; if (ftrace_hash_empty(hash)) return; for (i = 0; i < pg->index; i++) { rec = &pg->records[i]; entry = __ftrace_lookup_ip(hash, rec->ip); /* * Do not allow this rec to match again. * Yeah, it may waste some memory, but will be removed * if/when the hash is modified again. */ if (entry) entry->ip = 0; } } /* Clear any records from hashs */ static void clear_mod_from_hashes(struct ftrace_page *pg) { struct trace_array *tr; mutex_lock(&trace_types_lock); list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (!tr->ops || !tr->ops->func_hash) continue; mutex_lock(&tr->ops->func_hash->regex_lock); clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash); clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash); mutex_unlock(&tr->ops->func_hash->regex_lock); } mutex_unlock(&trace_types_lock); } static void ftrace_free_mod_map(struct rcu_head *rcu) { struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu); struct ftrace_mod_func *mod_func; struct ftrace_mod_func *n; /* All the contents of mod_map are now not visible to readers */ list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) { kfree(mod_func->name); list_del(&mod_func->list); kfree(mod_func); } kfree(mod_map); } void ftrace_release_mod(struct module *mod) { struct ftrace_mod_map *mod_map; struct ftrace_mod_map *n; struct dyn_ftrace *rec; struct ftrace_page **last_pg; struct ftrace_page *tmp_page = NULL; struct ftrace_page *pg; int order; mutex_lock(&ftrace_lock); if (ftrace_disabled) goto out_unlock; list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) { if (mod_map->mod == mod) { list_del_rcu(&mod_map->list); call_rcu(&mod_map->rcu, ftrace_free_mod_map); break; } } /* * Each module has its own ftrace_pages, remove * them from the list. */ last_pg = &ftrace_pages_start; for (pg = ftrace_pages_start; pg; pg = *last_pg) { rec = &pg->records[0]; if (within_module_core(rec->ip, mod) || within_module_init(rec->ip, mod)) { /* * As core pages are first, the first * page should never be a module page. */ if (WARN_ON(pg == ftrace_pages_start)) goto out_unlock; /* Check if we are deleting the last page */ if (pg == ftrace_pages) ftrace_pages = next_to_ftrace_page(last_pg); ftrace_update_tot_cnt -= pg->index; *last_pg = pg->next; pg->next = tmp_page; tmp_page = pg; } else last_pg = &pg->next; } out_unlock: mutex_unlock(&ftrace_lock); for (pg = tmp_page; pg; pg = tmp_page) { /* Needs to be called outside of ftrace_lock */ clear_mod_from_hashes(pg); order = get_count_order(pg->size / ENTRIES_PER_PAGE); free_pages((unsigned long)pg->records, order); tmp_page = pg->next; kfree(pg); } } void ftrace_module_enable(struct module *mod) { struct dyn_ftrace *rec; struct ftrace_page *pg; mutex_lock(&ftrace_lock); if (ftrace_disabled) goto out_unlock; /* * If the tracing is enabled, go ahead and enable the record. * * The reason not to enable the record immediatelly is the * inherent check of ftrace_make_nop/ftrace_make_call for * correct previous instructions. Making first the NOP * conversion puts the module to the correct state, thus * passing the ftrace_make_call check. * * We also delay this to after the module code already set the * text to read-only, as we now need to set it back to read-write * so that we can modify the text. */ if (ftrace_start_up) ftrace_arch_code_modify_prepare(); do_for_each_ftrace_rec(pg, rec) { int cnt; /* * do_for_each_ftrace_rec() is a double loop. * module text shares the pg. If a record is * not part of this module, then skip this pg, * which the "break" will do. */ if (!within_module_core(rec->ip, mod) && !within_module_init(rec->ip, mod)) break; cnt = 0; /* * When adding a module, we need to check if tracers are * currently enabled and if they are, and can trace this record, * we need to enable the module functions as well as update the * reference counts for those function records. */ if (ftrace_start_up) cnt += referenced_filters(rec); /* This clears FTRACE_FL_DISABLED */ rec->flags = cnt; if (ftrace_start_up && cnt) { int failed = __ftrace_replace_code(rec, 1); if (failed) { ftrace_bug(failed, rec); goto out_loop; } } } while_for_each_ftrace_rec(); out_loop: if (ftrace_start_up) ftrace_arch_code_modify_post_process(); out_unlock: mutex_unlock(&ftrace_lock); process_cached_mods(mod->name); } void ftrace_module_init(struct module *mod) { if (ftrace_disabled || !mod->num_ftrace_callsites) return; ftrace_process_locs(mod, mod->ftrace_callsites, mod->ftrace_callsites + mod->num_ftrace_callsites); } static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map, struct dyn_ftrace *rec) { struct ftrace_mod_func *mod_func; unsigned long symsize; unsigned long offset; char str[KSYM_SYMBOL_LEN]; char *modname; const char *ret; ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str); if (!ret) return; mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL); if (!mod_func) return; mod_func->name = kstrdup(str, GFP_KERNEL); if (!mod_func->name) { kfree(mod_func); return; } mod_func->ip = rec->ip - offset; mod_func->size = symsize; mod_map->num_funcs++; list_add_rcu(&mod_func->list, &mod_map->funcs); } static struct ftrace_mod_map * allocate_ftrace_mod_map(struct module *mod, unsigned long start, unsigned long end) { struct ftrace_mod_map *mod_map; mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL); if (!mod_map) return NULL; mod_map->mod = mod; mod_map->start_addr = start; mod_map->end_addr = end; mod_map->num_funcs = 0; INIT_LIST_HEAD_RCU(&mod_map->funcs); list_add_rcu(&mod_map->list, &ftrace_mod_maps); return mod_map; } static const char * ftrace_func_address_lookup(struct ftrace_mod_map *mod_map, unsigned long addr, unsigned long *size, unsigned long *off, char *sym) { struct ftrace_mod_func *found_func = NULL; struct ftrace_mod_func *mod_func; list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) { if (addr >= mod_func->ip && addr < mod_func->ip + mod_func->size) { found_func = mod_func; break; } } if (found_func) { if (size) *size = found_func->size; if (off) *off = addr - found_func->ip; if (sym) strlcpy(sym, found_func->name, KSYM_NAME_LEN); return found_func->name; } return NULL; } const char * ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, unsigned long *off, char **modname, char *sym) { struct ftrace_mod_map *mod_map; const char *ret = NULL; /* mod_map is freed via call_rcu() */ preempt_disable(); list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) { ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym); if (ret) { if (modname) *modname = mod_map->mod->name; break; } } preempt_enable(); return ret; } int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *name, char *module_name, int *exported) { struct ftrace_mod_map *mod_map; struct ftrace_mod_func *mod_func; preempt_disable(); list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) { if (symnum >= mod_map->num_funcs) { symnum -= mod_map->num_funcs; continue; } list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) { if (symnum > 1) { symnum--; continue; } *value = mod_func->ip; *type = 'T'; strlcpy(name, mod_func->name, KSYM_NAME_LEN); strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN); *exported = 1; preempt_enable(); return 0; } WARN_ON(1); break; } preempt_enable(); return -ERANGE; } #else static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map, struct dyn_ftrace *rec) { } static inline struct ftrace_mod_map * allocate_ftrace_mod_map(struct module *mod, unsigned long start, unsigned long end) { return NULL; } #endif /* CONFIG_MODULES */ struct ftrace_init_func { struct list_head list; unsigned long ip; }; /* Clear any init ips from hashes */ static void clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash) { struct ftrace_func_entry *entry; if (ftrace_hash_empty(hash)) return; entry = __ftrace_lookup_ip(hash, func->ip); /* * Do not allow this rec to match again. * Yeah, it may waste some memory, but will be removed * if/when the hash is modified again. */ if (entry) entry->ip = 0; } static void clear_func_from_hashes(struct ftrace_init_func *func) { struct trace_array *tr; mutex_lock(&trace_types_lock); list_for_each_entry(tr, &ftrace_trace_arrays, list) { if (!tr->ops || !tr->ops->func_hash) continue; mutex_lock(&tr->ops->func_hash->regex_lock); clear_func_from_hash(func, tr->ops->func_hash->filter_hash); clear_func_from_hash(func, tr->ops->func_hash->notrace_hash); mutex_unlock(&tr->ops->func_hash->regex_lock); } mutex_unlock(&trace_types_lock); } static void add_to_clear_hash_list(struct list_head *clear_list, struct dyn_ftrace *rec) { struct ftrace_init_func *func; func = kmalloc(sizeof(*func), GFP_KERNEL); if (!func) { WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n"); return; } func->ip = rec->ip; list_add(&func->list, clear_list); } void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr) { unsigned long start = (unsigned long)(start_ptr); unsigned long end = (unsigned long)(end_ptr); struct ftrace_page **last_pg = &ftrace_pages_start; struct ftrace_page *pg; struct dyn_ftrace *rec; struct dyn_ftrace key; struct ftrace_mod_map *mod_map = NULL; struct ftrace_init_func *func, *func_next; struct list_head clear_hash; int order; INIT_LIST_HEAD(&clear_hash); key.ip = start; key.flags = end; /* overload flags, as it is unsigned long */ mutex_lock(&ftrace_lock); /* * If we are freeing module init memory, then check if * any tracer is active. If so, we need to save a mapping of * the module functions being freed with the address. */ if (mod && ftrace_ops_list != &ftrace_list_end) mod_map = allocate_ftrace_mod_map(mod, start, end); for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) { if (end < pg->records[0].ip || start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) continue; again: rec = bsearch(&key, pg->records, pg->index, sizeof(struct dyn_ftrace), ftrace_cmp_recs); if (!rec) continue; /* rec will be cleared from hashes after ftrace_lock unlock */ add_to_clear_hash_list(&clear_hash, rec); if (mod_map) save_ftrace_mod_rec(mod_map, rec); pg->index--; ftrace_update_tot_cnt--; if (!pg->index) { *last_pg = pg->next; order = get_count_order(pg->size / ENTRIES_PER_PAGE); free_pages((unsigned long)pg->records, order); kfree(pg); pg = container_of(last_pg, struct ftrace_page, next); if (!(*last_pg)) ftrace_pages = pg; continue; } memmove(rec, rec + 1, (pg->index - (rec - pg->records)) * sizeof(*rec)); /* More than one function may be in this block */ goto again; } mutex_unlock(&ftrace_lock); list_for_each_entry_safe(func, func_next, &clear_hash, list) { clear_func_from_hashes(func); kfree(func); } } void __init ftrace_free_init_mem(void) { void *start = (void *)(&__init_begin); void *end = (void *)(&__init_end); ftrace_free_mem(NULL, start, end); } void __init ftrace_init(void) { extern unsigned long __start_mcount_loc[]; extern unsigned long __stop_mcount_loc[]; unsigned long count, flags; int ret; local_irq_save(flags); ret = ftrace_dyn_arch_init(); local_irq_restore(flags); if (ret) goto failed; count = __stop_mcount_loc - __start_mcount_loc; if (!count) { pr_info("ftrace: No functions to be traced?\n"); goto failed; } pr_info("ftrace: allocating %ld entries in %ld pages\n", count, count / ENTRIES_PER_PAGE + 1); last_ftrace_enabled = ftrace_enabled = 1; ret = ftrace_process_locs(NULL, __start_mcount_loc, __stop_mcount_loc); set_ftrace_early_filters(); return; failed: ftrace_disabled = 1; } /* Do nothing if arch does not support this */ void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops) { } static void ftrace_update_trampoline(struct ftrace_ops *ops) { arch_ftrace_update_trampoline(ops); } void ftrace_init_trace_array(struct trace_array *tr) { INIT_LIST_HEAD(&tr->func_probes); INIT_LIST_HEAD(&tr->mod_trace); INIT_LIST_HEAD(&tr->mod_notrace); } #else struct ftrace_ops global_ops = { .func = ftrace_stub, .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID, }; static int __init ftrace_nodyn_init(void) { ftrace_enabled = 1; return 0; } core_initcall(ftrace_nodyn_init); static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; } static inline void ftrace_startup_enable(int command) { } static inline void ftrace_startup_all(int command) { } # define ftrace_startup_sysctl() do { } while (0) # define ftrace_shutdown_sysctl() do { } while (0) static void ftrace_update_trampoline(struct ftrace_ops *ops) { } #endif /* CONFIG_DYNAMIC_FTRACE */ __init void ftrace_init_global_array_ops(struct trace_array *tr) { tr->ops = &global_ops; tr->ops->private = tr; ftrace_init_trace_array(tr); } void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func) { /* If we filter on pids, update to use the pid function */ if (tr->flags & TRACE_ARRAY_FL_GLOBAL) { if (WARN_ON(tr->ops->func != ftrace_stub)) printk("ftrace ops had %pS for function\n", tr->ops->func); } tr->ops->func = func; tr->ops->private = tr; } void ftrace_reset_array_ops(struct trace_array *tr) { tr->ops->func = ftrace_stub; } static inline void __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ignored, struct pt_regs *regs) { struct ftrace_ops *op; int bit; bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; /* * Some of the ops may be dynamically allocated, * they must be freed after a synchronize_rcu(). */ preempt_disable_notrace(); do_for_each_ftrace_op(op, ftrace_ops_list) { /* * Check the following for each ops before calling their func: * if RCU flag is set, then rcu_is_watching() must be true * if PER_CPU is set, then ftrace_function_local_disable() * must be false * Otherwise test if the ip matches the ops filter * * If any of the above fails then the op->func() is not executed. */ if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) && ftrace_ops_test(op, ip, regs)) { if (FTRACE_WARN_ON(!op->func)) { pr_warn("op=%p %pS\n", op, op); goto out; } op->func(ip, parent_ip, op, regs); } } while_for_each_ftrace_op(op); out: preempt_enable_notrace(); trace_clear_recursion(bit); } /* * Some archs only support passing ip and parent_ip. Even though * the list function ignores the op parameter, we do not want any * C side effects, where a function is called without the caller * sending a third parameter. * Archs are to support both the regs and ftrace_ops at the same time. * If they support ftrace_ops, it is assumed they support regs. * If call backs want to use regs, they must either check for regs * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS. * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved. * An architecture can pass partial regs with ftrace_ops and still * set the ARCH_SUPPORTS_FTRACE_OPS. */ #if ARCH_SUPPORTS_FTRACE_OPS static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { __ftrace_ops_list_func(ip, parent_ip, NULL, regs); } #else static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip) { __ftrace_ops_list_func(ip, parent_ip, NULL, NULL); } #endif /* * If there's only one function registered but it does not support * recursion, needs RCU protection and/or requires per cpu handling, then * this function will be called by the mcount trampoline. */ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs) { int bit; if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching()) return; bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; preempt_disable_notrace(); op->func(ip, parent_ip, op, regs); preempt_enable_notrace(); trace_clear_recursion(bit); } /** * ftrace_ops_get_func - get the function a trampoline should call * @ops: the ops to get the function for * * Normally the mcount trampoline will call the ops->func, but there * are times that it should not. For example, if the ops does not * have its own recursion protection, then it should call the * ftrace_ops_assist_func() instead. * * Returns the function that the trampoline should call for @ops. */ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) { /* * If the function does not handle recursion, needs to be RCU safe, * or does per cpu logic, then we need to call the assist handler. */ if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) || ops->flags & FTRACE_OPS_FL_RCU) return ftrace_ops_assist_func; return ops->func; } static void ftrace_filter_pid_sched_switch_probe(void *data, bool preempt, struct task_struct *prev, struct task_struct *next) { struct trace_array *tr = data; struct trace_pid_list *pid_list; pid_list = rcu_dereference_sched(tr->function_pids); this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, trace_ignore_this_task(pid_list, next)); } static void ftrace_pid_follow_sched_process_fork(void *data, struct task_struct *self, struct task_struct *task) { struct trace_pid_list *pid_list; struct trace_array *tr = data; pid_list = rcu_dereference_sched(tr->function_pids); trace_filter_add_remove_task(pid_list, self, task); } static void ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task) { struct trace_pid_list *pid_list; struct trace_array *tr = data; pid_list = rcu_dereference_sched(tr->function_pids); trace_filter_add_remove_task(pid_list, NULL, task); } void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) { if (enable) { register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, tr); register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, tr); } else { unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork, tr); unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit, tr); } } static void clear_ftrace_pids(struct trace_array *tr) { struct trace_pid_list *pid_list; int cpu; pid_list = rcu_dereference_protected(tr->function_pids, lockdep_is_held(&ftrace_lock)); if (!pid_list) return; unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); for_each_possible_cpu(cpu) per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false; rcu_assign_pointer(tr->function_pids, NULL); /* Wait till all users are no longer using pid filtering */ synchronize_rcu(); trace_free_pid_list(pid_list); } void ftrace_clear_pids(struct trace_array *tr) { mutex_lock(&ftrace_lock); clear_ftrace_pids(tr); mutex_unlock(&ftrace_lock); } static void ftrace_pid_reset(struct trace_array *tr) { mutex_lock(&ftrace_lock); clear_ftrace_pids(tr); ftrace_update_pid_func(); ftrace_startup_all(0); mutex_unlock(&ftrace_lock); } /* Greater than any max PID */ #define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1) static void *fpid_start(struct seq_file *m, loff_t *pos) __acquires(RCU) { struct trace_pid_list *pid_list; struct trace_array *tr = m->private; mutex_lock(&ftrace_lock); rcu_read_lock_sched(); pid_list = rcu_dereference_sched(tr->function_pids); if (!pid_list) return !(*pos) ? FTRACE_NO_PIDS : NULL; return trace_pid_start(pid_list, pos); } static void *fpid_next(struct seq_file *m, void *v, loff_t *pos) { struct trace_array *tr = m->private; struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids); if (v == FTRACE_NO_PIDS) return NULL; return trace_pid_next(pid_list, v, pos); } static void fpid_stop(struct seq_file *m, void *p) __releases(RCU) { rcu_read_unlock_sched(); mutex_unlock(&ftrace_lock); } static int fpid_show(struct seq_file *m, void *v) { if (v == FTRACE_NO_PIDS) { seq_puts(m, "no pid\n"); return 0; } return trace_pid_show(m, v); } static const struct seq_operations ftrace_pid_sops = { .start = fpid_start, .next = fpid_next, .stop = fpid_stop, .show = fpid_show, }; static int ftrace_pid_open(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; struct seq_file *m; int ret = 0; if (trace_array_get(tr) < 0) return -ENODEV; if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) ftrace_pid_reset(tr); ret = seq_open(file, &ftrace_pid_sops); if (ret < 0) { trace_array_put(tr); } else { m = file->private_data; /* copy tr over to seq ops */ m->private = tr; } return ret; } static void ignore_task_cpu(void *data) { struct trace_array *tr = data; struct trace_pid_list *pid_list; /* * This function is called by on_each_cpu() while the * event_mutex is held. */ pid_list = rcu_dereference_protected(tr->function_pids, mutex_is_locked(&ftrace_lock)); this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid, trace_ignore_this_task(pid_list, current)); } static ssize_t ftrace_pid_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { struct seq_file *m = filp->private_data; struct trace_array *tr = m->private; struct trace_pid_list *filtered_pids = NULL; struct trace_pid_list *pid_list; ssize_t ret; if (!cnt) return 0; mutex_lock(&ftrace_lock); filtered_pids = rcu_dereference_protected(tr->function_pids, lockdep_is_held(&ftrace_lock)); ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt); if (ret < 0) goto out; rcu_assign_pointer(tr->function_pids, pid_list); if (filtered_pids) { synchronize_rcu(); trace_free_pid_list(filtered_pids); } else if (pid_list) { /* Register a probe to set whether to ignore the tracing of a task */ register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr); } /* * Ignoring of pids is done at task switch. But we have to * check for those tasks that are currently running. * Always do this in case a pid was appended or removed. */ on_each_cpu(ignore_task_cpu, tr, 1); ftrace_update_pid_func(); ftrace_startup_all(0); out: mutex_unlock(&ftrace_lock); if (ret > 0) *ppos += ret; return ret; } static int ftrace_pid_release(struct inode *inode, struct file *file) { struct trace_array *tr = inode->i_private; trace_array_put(tr); return seq_release(inode, file); } static const struct file_operations ftrace_pid_fops = { .open = ftrace_pid_open, .write = ftrace_pid_write, .read = seq_read, .llseek = tracing_lseek, .release = ftrace_pid_release, }; void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer) { trace_create_file("set_ftrace_pid", 0644, d_tracer, tr, &ftrace_pid_fops); } void __init ftrace_init_tracefs_toplevel(struct trace_array *tr, struct dentry *d_tracer) { /* Only the top level directory has the dyn_tracefs and profile */ WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL)); ftrace_init_dyn_tracefs(d_tracer); ftrace_profile_tracefs(d_tracer); } /** * ftrace_kill - kill ftrace * * This function should be used by panic code. It stops ftrace * but in a not so nice way. If you need to simply kill ftrace * from a non-atomic section, use ftrace_kill. */ void ftrace_kill(void) { ftrace_disabled = 1; ftrace_enabled = 0; ftrace_trace_function = ftrace_stub; } /** * Test if ftrace is dead or not. */ int ftrace_is_dead(void) { return ftrace_disabled; } /** * register_ftrace_function - register a function for profiling * @ops - ops structure that holds the function for profiling. * * Register a function to be called by all functions in the * kernel. * * Note: @ops->func and all the functions it calls must be labeled * with "notrace", otherwise it will go into a * recursive loop. */ int register_ftrace_function(struct ftrace_ops *ops) { int ret = -1; ftrace_ops_init(ops); mutex_lock(&ftrace_lock); ret = ftrace_startup(ops, 0); mutex_unlock(&ftrace_lock); return ret; } EXPORT_SYMBOL_GPL(register_ftrace_function); /** * unregister_ftrace_function - unregister a function for profiling. * @ops - ops structure that holds the function to unregister * * Unregister a function that was added to be called by ftrace profiling. */ int unregister_ftrace_function(struct ftrace_ops *ops) { int ret; mutex_lock(&ftrace_lock); ret = ftrace_shutdown(ops, 0); mutex_unlock(&ftrace_lock); return ret; } EXPORT_SYMBOL_GPL(unregister_ftrace_function); int ftrace_enable_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret = -ENODEV; mutex_lock(&ftrace_lock); if (unlikely(ftrace_disabled)) goto out; ret = proc_dointvec(table, write, buffer, lenp, ppos); if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) goto out; last_ftrace_enabled = !!ftrace_enabled; if (ftrace_enabled) { /* we are starting ftrace again */ if (rcu_dereference_protected(ftrace_ops_list, lockdep_is_held(&ftrace_lock)) != &ftrace_list_end) update_ftrace_function(); ftrace_startup_sysctl(); } else { /* stopping ftrace calls (just send to ftrace_stub) */ ftrace_trace_function = ftrace_stub; ftrace_shutdown_sysctl(); } out: mutex_unlock(&ftrace_lock); return ret; }
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