| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Hendrik Brueckner | 5382 | 62.79% | 16 | 25.40% |
| Pu Hou | 1773 | 20.69% | 4 | 6.35% |
| Thomas Richter | 910 | 10.62% | 19 | 30.16% |
| Heiko Carstens | 373 | 4.35% | 6 | 9.52% |
| Christian Bornträger | 38 | 0.44% | 4 | 6.35% |
| Sebastian Andrzej Siewior | 37 | 0.43% | 1 | 1.59% |
| Christoph Lameter | 14 | 0.16% | 1 | 1.59% |
| Thomas Gleixner | 11 | 0.13% | 2 | 3.17% |
| Anna-Maria Gleixner | 8 | 0.09% | 1 | 1.59% |
| Linus Torvalds | 7 | 0.08% | 1 | 1.59% |
| Mathieu J. Poirier | 5 | 0.06% | 1 | 1.59% |
| Thomas Huth | 4 | 0.05% | 1 | 1.59% |
| Martin Schwidefsky | 4 | 0.05% | 2 | 3.17% |
| Peter Zijlstra | 2 | 0.02% | 1 | 1.59% |
| Luis R. Rodriguez | 1 | 0.01% | 1 | 1.59% |
| Greg Kroah-Hartman | 1 | 0.01% | 1 | 1.59% |
| Eric W. Biedermann | 1 | 0.01% | 1 | 1.59% |
| Total | 8571 | 63 |
// SPDX-License-Identifier: GPL-2.0 /* * Performance event support for the System z CPU-measurement Sampling Facility * * Copyright IBM Corp. 2013, 2018 * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> */ #define KMSG_COMPONENT "cpum_sf" #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt #include <linux/kernel.h> #include <linux/kernel_stat.h> #include <linux/perf_event.h> #include <linux/percpu.h> #include <linux/pid.h> #include <linux/notifier.h> #include <linux/export.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/moduleparam.h> #include <asm/cpu_mf.h> #include <asm/irq.h> #include <asm/debug.h> #include <asm/timex.h> /* Minimum number of sample-data-block-tables: * At least one table is required for the sampling buffer structure. * A single table contains up to 511 pointers to sample-data-blocks. */ #define CPUM_SF_MIN_SDBT 1 /* Number of sample-data-blocks per sample-data-block-table (SDBT): * A table contains SDB pointers (8 bytes) and one table-link entry * that points to the origin of the next SDBT. */ #define CPUM_SF_SDB_PER_TABLE ((PAGE_SIZE - 8) / 8) /* Maximum page offset for an SDBT table-link entry: * If this page offset is reached, a table-link entry to the next SDBT * must be added. */ #define CPUM_SF_SDBT_TL_OFFSET (CPUM_SF_SDB_PER_TABLE * 8) static inline int require_table_link(const void *sdbt) { return ((unsigned long) sdbt & ~PAGE_MASK) == CPUM_SF_SDBT_TL_OFFSET; } /* Minimum and maximum sampling buffer sizes: * * This number represents the maximum size of the sampling buffer taking * the number of sample-data-block-tables into account. Note that these * numbers apply to the basic-sampling function only. * The maximum number of SDBs is increased by CPUM_SF_SDB_DIAG_FACTOR if * the diagnostic-sampling function is active. * * Sampling buffer size Buffer characteristics * --------------------------------------------------- * 64KB == 16 pages (4KB per page) * 1 page for SDB-tables * 15 pages for SDBs * * 32MB == 8192 pages (4KB per page) * 16 pages for SDB-tables * 8176 pages for SDBs */ static unsigned long __read_mostly CPUM_SF_MIN_SDB = 15; static unsigned long __read_mostly CPUM_SF_MAX_SDB = 8176; static unsigned long __read_mostly CPUM_SF_SDB_DIAG_FACTOR = 1; struct sf_buffer { unsigned long *sdbt; /* Sample-data-block-table origin */ /* buffer characteristics (required for buffer increments) */ unsigned long num_sdb; /* Number of sample-data-blocks */ unsigned long num_sdbt; /* Number of sample-data-block-tables */ unsigned long *tail; /* last sample-data-block-table */ }; struct aux_buffer { struct sf_buffer sfb; unsigned long head; /* index of SDB of buffer head */ unsigned long alert_mark; /* index of SDB of alert request position */ unsigned long empty_mark; /* mark of SDB not marked full */ unsigned long *sdb_index; /* SDB address for fast lookup */ unsigned long *sdbt_index; /* SDBT address for fast lookup */ }; struct cpu_hw_sf { /* CPU-measurement sampling information block */ struct hws_qsi_info_block qsi; /* CPU-measurement sampling control block */ struct hws_lsctl_request_block lsctl; struct sf_buffer sfb; /* Sampling buffer */ unsigned int flags; /* Status flags */ struct perf_event *event; /* Scheduled perf event */ struct perf_output_handle handle; /* AUX buffer output handle */ }; static DEFINE_PER_CPU(struct cpu_hw_sf, cpu_hw_sf); /* Debug feature */ static debug_info_t *sfdbg; /* * sf_disable() - Switch off sampling facility */ static int sf_disable(void) { struct hws_lsctl_request_block sreq; memset(&sreq, 0, sizeof(sreq)); return lsctl(&sreq); } /* * sf_buffer_available() - Check for an allocated sampling buffer */ static int sf_buffer_available(struct cpu_hw_sf *cpuhw) { return !!cpuhw->sfb.sdbt; } /* * deallocate sampling facility buffer */ static void free_sampling_buffer(struct sf_buffer *sfb) { unsigned long *sdbt, *curr; if (!sfb->sdbt) return; sdbt = sfb->sdbt; curr = sdbt; /* Free the SDBT after all SDBs are processed... */ while (1) { if (!*curr || !sdbt) break; /* Process table-link entries */ if (is_link_entry(curr)) { curr = get_next_sdbt(curr); if (sdbt) free_page((unsigned long) sdbt); /* If the origin is reached, sampling buffer is freed */ if (curr == sfb->sdbt) break; else sdbt = curr; } else { /* Process SDB pointer */ if (*curr) { free_page(*curr); curr++; } } } debug_sprintf_event(sfdbg, 5, "%s: freed sdbt %#lx\n", __func__, (unsigned long)sfb->sdbt); memset(sfb, 0, sizeof(*sfb)); } static int alloc_sample_data_block(unsigned long *sdbt, gfp_t gfp_flags) { struct hws_trailer_entry *te; unsigned long sdb; /* Allocate and initialize sample-data-block */ sdb = get_zeroed_page(gfp_flags); if (!sdb) return -ENOMEM; te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb); te->header.a = 1; /* Link SDB into the sample-data-block-table */ *sdbt = sdb; return 0; } /* * realloc_sampling_buffer() - extend sampler memory * * Allocates new sample-data-blocks and adds them to the specified sampling * buffer memory. * * Important: This modifies the sampling buffer and must be called when the * sampling facility is disabled. * * Returns zero on success, non-zero otherwise. */ static int realloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb, gfp_t gfp_flags) { int i, rc; unsigned long *new, *tail, *tail_prev = NULL; if (!sfb->sdbt || !sfb->tail) return -EINVAL; if (!is_link_entry(sfb->tail)) return -EINVAL; /* Append to the existing sampling buffer, overwriting the table-link * register. * The tail variables always points to the "tail" (last and table-link) * entry in an SDB-table. */ tail = sfb->tail; /* Do a sanity check whether the table-link entry points to * the sampling buffer origin. */ if (sfb->sdbt != get_next_sdbt(tail)) { debug_sprintf_event(sfdbg, 3, "%s: " "sampling buffer is not linked: origin %#lx" " tail %#lx\n", __func__, (unsigned long)sfb->sdbt, (unsigned long)tail); return -EINVAL; } /* Allocate remaining SDBs */ rc = 0; for (i = 0; i < num_sdb; i++) { /* Allocate a new SDB-table if it is full. */ if (require_table_link(tail)) { new = (unsigned long *) get_zeroed_page(gfp_flags); if (!new) { rc = -ENOMEM; break; } sfb->num_sdbt++; /* Link current page to tail of chain */ *tail = (unsigned long)(void *) new + 1; tail_prev = tail; tail = new; } /* Allocate a new sample-data-block. * If there is not enough memory, stop the realloc process * and simply use what was allocated. If this is a temporary * issue, a new realloc call (if required) might succeed. */ rc = alloc_sample_data_block(tail, gfp_flags); if (rc) { /* Undo last SDBT. An SDBT with no SDB at its first * entry but with an SDBT entry instead can not be * handled by the interrupt handler code. * Avoid this situation. */ if (tail_prev) { sfb->num_sdbt--; free_page((unsigned long) new); tail = tail_prev; } break; } sfb->num_sdb++; tail++; tail_prev = new = NULL; /* Allocated at least one SBD */ } /* Link sampling buffer to its origin */ *tail = (unsigned long) sfb->sdbt + 1; sfb->tail = tail; debug_sprintf_event(sfdbg, 4, "%s: new buffer" " settings: sdbt %lu sdb %lu\n", __func__, sfb->num_sdbt, sfb->num_sdb); return rc; } /* * allocate_sampling_buffer() - allocate sampler memory * * Allocates and initializes a sampling buffer structure using the * specified number of sample-data-blocks (SDB). For each allocation, * a 4K page is used. The number of sample-data-block-tables (SDBT) * are calculated from SDBs. * Also set the ALERT_REQ mask in each SDBs trailer. * * Returns zero on success, non-zero otherwise. */ static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb) { int rc; if (sfb->sdbt) return -EINVAL; /* Allocate the sample-data-block-table origin */ sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); if (!sfb->sdbt) return -ENOMEM; sfb->num_sdb = 0; sfb->num_sdbt = 1; /* Link the table origin to point to itself to prepare for * realloc_sampling_buffer() invocation. */ sfb->tail = sfb->sdbt; *sfb->tail = (unsigned long)(void *) sfb->sdbt + 1; /* Allocate requested number of sample-data-blocks */ rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL); if (rc) { free_sampling_buffer(sfb); debug_sprintf_event(sfdbg, 4, "%s: " "realloc_sampling_buffer failed with rc %i\n", __func__, rc); } else debug_sprintf_event(sfdbg, 4, "%s: tear %#lx dear %#lx\n", __func__, (unsigned long)sfb->sdbt, (unsigned long)*sfb->sdbt); return rc; } static void sfb_set_limits(unsigned long min, unsigned long max) { struct hws_qsi_info_block si; CPUM_SF_MIN_SDB = min; CPUM_SF_MAX_SDB = max; memset(&si, 0, sizeof(si)); if (!qsi(&si)) CPUM_SF_SDB_DIAG_FACTOR = DIV_ROUND_UP(si.dsdes, si.bsdes); } static unsigned long sfb_max_limit(struct hw_perf_event *hwc) { return SAMPL_DIAG_MODE(hwc) ? CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR : CPUM_SF_MAX_SDB; } static unsigned long sfb_pending_allocs(struct sf_buffer *sfb, struct hw_perf_event *hwc) { if (!sfb->sdbt) return SFB_ALLOC_REG(hwc); if (SFB_ALLOC_REG(hwc) > sfb->num_sdb) return SFB_ALLOC_REG(hwc) - sfb->num_sdb; return 0; } static int sfb_has_pending_allocs(struct sf_buffer *sfb, struct hw_perf_event *hwc) { return sfb_pending_allocs(sfb, hwc) > 0; } static void sfb_account_allocs(unsigned long num, struct hw_perf_event *hwc) { /* Limit the number of SDBs to not exceed the maximum */ num = min_t(unsigned long, num, sfb_max_limit(hwc) - SFB_ALLOC_REG(hwc)); if (num) SFB_ALLOC_REG(hwc) += num; } static void sfb_init_allocs(unsigned long num, struct hw_perf_event *hwc) { SFB_ALLOC_REG(hwc) = 0; sfb_account_allocs(num, hwc); } static void deallocate_buffers(struct cpu_hw_sf *cpuhw) { if (cpuhw->sfb.sdbt) free_sampling_buffer(&cpuhw->sfb); } static int allocate_buffers(struct cpu_hw_sf *cpuhw, struct hw_perf_event *hwc) { unsigned long n_sdb, freq; size_t sample_size; /* Calculate sampling buffers using 4K pages * * 1. The sampling size is 32 bytes for basic sampling. This size * is the same for all machine types. Diagnostic * sampling uses auxlilary data buffer setup which provides the * memory for SDBs using linux common code auxiliary trace * setup. * * 2. Function alloc_sampling_buffer() sets the Alert Request * Control indicator to trigger a measurement-alert to harvest * sample-data-blocks (SDB). This is done per SDB. This * measurement alert interrupt fires quick enough to handle * one SDB, on very high frequency and work loads there might * be 2 to 3 SBDs available for sample processing. * Currently there is no need for setup alert request on every * n-th page. This is counterproductive as one IRQ triggers * a very high number of samples to be processed at one IRQ. * * 3. Use the sampling frequency as input. * Compute the number of SDBs and ensure a minimum * of CPUM_SF_MIN_SDB. Depending on frequency add some more * SDBs to handle a higher sampling rate. * Use a minimum of CPUM_SF_MIN_SDB and allow for 100 samples * (one SDB) for every 10000 HZ frequency increment. * * 4. Compute the number of sample-data-block-tables (SDBT) and * ensure a minimum of CPUM_SF_MIN_SDBT (one table can manage up * to 511 SDBs). */ sample_size = sizeof(struct hws_basic_entry); freq = sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc)); n_sdb = CPUM_SF_MIN_SDB + DIV_ROUND_UP(freq, 10000); /* If there is already a sampling buffer allocated, it is very likely * that the sampling facility is enabled too. If the event to be * initialized requires a greater sampling buffer, the allocation must * be postponed. Changing the sampling buffer requires the sampling * facility to be in the disabled state. So, account the number of * required SDBs and let cpumsf_pmu_enable() resize the buffer just * before the event is started. */ sfb_init_allocs(n_sdb, hwc); if (sf_buffer_available(cpuhw)) return 0; debug_sprintf_event(sfdbg, 3, "%s: rate %lu f %lu sdb %lu/%lu" " sample_size %lu cpuhw %p\n", __func__, SAMPL_RATE(hwc), freq, n_sdb, sfb_max_limit(hwc), sample_size, cpuhw); return alloc_sampling_buffer(&cpuhw->sfb, sfb_pending_allocs(&cpuhw->sfb, hwc)); } static unsigned long min_percent(unsigned int percent, unsigned long base, unsigned long min) { return min_t(unsigned long, min, DIV_ROUND_UP(percent * base, 100)); } static unsigned long compute_sfb_extent(unsigned long ratio, unsigned long base) { /* Use a percentage-based approach to extend the sampling facility * buffer. Accept up to 5% sample data loss. * Vary the extents between 1% to 5% of the current number of * sample-data-blocks. */ if (ratio <= 5) return 0; if (ratio <= 25) return min_percent(1, base, 1); if (ratio <= 50) return min_percent(1, base, 1); if (ratio <= 75) return min_percent(2, base, 2); if (ratio <= 100) return min_percent(3, base, 3); if (ratio <= 250) return min_percent(4, base, 4); return min_percent(5, base, 8); } static void sfb_account_overflows(struct cpu_hw_sf *cpuhw, struct hw_perf_event *hwc) { unsigned long ratio, num; if (!OVERFLOW_REG(hwc)) return; /* The sample_overflow contains the average number of sample data * that has been lost because sample-data-blocks were full. * * Calculate the total number of sample data entries that has been * discarded. Then calculate the ratio of lost samples to total samples * per second in percent. */ ratio = DIV_ROUND_UP(100 * OVERFLOW_REG(hwc) * cpuhw->sfb.num_sdb, sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc))); /* Compute number of sample-data-blocks */ num = compute_sfb_extent(ratio, cpuhw->sfb.num_sdb); if (num) sfb_account_allocs(num, hwc); debug_sprintf_event(sfdbg, 5, "%s: overflow %llu ratio %lu num %lu\n", __func__, OVERFLOW_REG(hwc), ratio, num); OVERFLOW_REG(hwc) = 0; } /* extend_sampling_buffer() - Extend sampling buffer * @sfb: Sampling buffer structure (for local CPU) * @hwc: Perf event hardware structure * * Use this function to extend the sampling buffer based on the overflow counter * and postponed allocation extents stored in the specified Perf event hardware. * * Important: This function disables the sampling facility in order to safely * change the sampling buffer structure. Do not call this function * when the PMU is active. */ static void extend_sampling_buffer(struct sf_buffer *sfb, struct hw_perf_event *hwc) { unsigned long num, num_old; int rc; num = sfb_pending_allocs(sfb, hwc); if (!num) return; num_old = sfb->num_sdb; /* Disable the sampling facility to reset any states and also * clear pending measurement alerts. */ sf_disable(); /* Extend the sampling buffer. * This memory allocation typically happens in an atomic context when * called by perf. Because this is a reallocation, it is fine if the * new SDB-request cannot be satisfied immediately. */ rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC); if (rc) debug_sprintf_event(sfdbg, 5, "%s: realloc failed with rc %i\n", __func__, rc); if (sfb_has_pending_allocs(sfb, hwc)) debug_sprintf_event(sfdbg, 5, "%s: " "req %lu alloc %lu remaining %lu\n", __func__, num, sfb->num_sdb - num_old, sfb_pending_allocs(sfb, hwc)); } /* Number of perf events counting hardware events */ static atomic_t num_events; /* Used to avoid races in calling reserve/release_cpumf_hardware */ static DEFINE_MUTEX(pmc_reserve_mutex); #define PMC_INIT 0 #define PMC_RELEASE 1 #define PMC_FAILURE 2 static void setup_pmc_cpu(void *flags) { int err; struct cpu_hw_sf *cpusf = this_cpu_ptr(&cpu_hw_sf); err = 0; switch (*((int *) flags)) { case PMC_INIT: memset(cpusf, 0, sizeof(*cpusf)); err = qsi(&cpusf->qsi); if (err) break; cpusf->flags |= PMU_F_RESERVED; err = sf_disable(); if (err) pr_err("Switching off the sampling facility failed " "with rc %i\n", err); debug_sprintf_event(sfdbg, 5, "%s: initialized: cpuhw %p\n", __func__, cpusf); break; case PMC_RELEASE: cpusf->flags &= ~PMU_F_RESERVED; err = sf_disable(); if (err) { pr_err("Switching off the sampling facility failed " "with rc %i\n", err); } else deallocate_buffers(cpusf); debug_sprintf_event(sfdbg, 5, "%s: released: cpuhw %p\n", __func__, cpusf); break; } if (err) *((int *) flags) |= PMC_FAILURE; } static void release_pmc_hardware(void) { int flags = PMC_RELEASE; irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT); on_each_cpu(setup_pmc_cpu, &flags, 1); } static int reserve_pmc_hardware(void) { int flags = PMC_INIT; on_each_cpu(setup_pmc_cpu, &flags, 1); if (flags & PMC_FAILURE) { release_pmc_hardware(); return -ENODEV; } irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT); return 0; } static void hw_perf_event_destroy(struct perf_event *event) { /* Release PMC if this is the last perf event */ if (!atomic_add_unless(&num_events, -1, 1)) { mutex_lock(&pmc_reserve_mutex); if (atomic_dec_return(&num_events) == 0) release_pmc_hardware(); mutex_unlock(&pmc_reserve_mutex); } } static void hw_init_period(struct hw_perf_event *hwc, u64 period) { hwc->sample_period = period; hwc->last_period = hwc->sample_period; local64_set(&hwc->period_left, hwc->sample_period); } static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si, unsigned long rate) { return clamp_t(unsigned long, rate, si->min_sampl_rate, si->max_sampl_rate); } static u32 cpumsf_pid_type(struct perf_event *event, u32 pid, enum pid_type type) { struct task_struct *tsk; /* Idle process */ if (!pid) goto out; tsk = find_task_by_pid_ns(pid, &init_pid_ns); pid = -1; if (tsk) { /* * Only top level events contain the pid namespace in which * they are created. */ if (event->parent) event = event->parent; pid = __task_pid_nr_ns(tsk, type, event->ns); /* * See also 1d953111b648 * "perf/core: Don't report zero PIDs for exiting tasks". */ if (!pid && !pid_alive(tsk)) pid = -1; } out: return pid; } static void cpumsf_output_event_pid(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { u32 pid; struct perf_event_header header; struct perf_output_handle handle; /* * Obtain the PID from the basic-sampling data entry and * correct the data->tid_entry.pid value. */ pid = data->tid_entry.pid; /* Protect callchain buffers, tasks */ rcu_read_lock(); perf_prepare_sample(&header, data, event, regs); if (perf_output_begin(&handle, data, event, header.size)) goto out; /* Update the process ID (see also kernel/events/core.c) */ data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); perf_output_sample(&handle, &header, data, event); perf_output_end(&handle); out: rcu_read_unlock(); } static unsigned long getrate(bool freq, unsigned long sample, struct hws_qsi_info_block *si) { unsigned long rate; if (freq) { rate = freq_to_sample_rate(si, sample); rate = hw_limit_rate(si, rate); } else { /* The min/max sampling rates specifies the valid range * of sample periods. If the specified sample period is * out of range, limit the period to the range boundary. */ rate = hw_limit_rate(si, sample); /* The perf core maintains a maximum sample rate that is * configurable through the sysctl interface. Ensure the * sampling rate does not exceed this value. This also helps * to avoid throttling when pushing samples with * perf_event_overflow(). */ if (sample_rate_to_freq(si, rate) > sysctl_perf_event_sample_rate) { debug_sprintf_event(sfdbg, 1, "%s: " "Sampling rate exceeds maximum " "perf sample rate\n", __func__); rate = 0; } } return rate; } /* The sampling information (si) contains information about the * min/max sampling intervals and the CPU speed. So calculate the * correct sampling interval and avoid the whole period adjust * feedback loop. * * Since the CPU Measurement sampling facility can not handle frequency * calculate the sampling interval when frequency is specified using * this formula: * interval := cpu_speed * 1000000 / sample_freq * * Returns errno on bad input and zero on success with parameter interval * set to the correct sampling rate. * * Note: This function turns off freq bit to avoid calling function * perf_adjust_period(). This causes frequency adjustment in the common * code part which causes tremendous variations in the counter values. */ static int __hw_perf_event_init_rate(struct perf_event *event, struct hws_qsi_info_block *si) { struct perf_event_attr *attr = &event->attr; struct hw_perf_event *hwc = &event->hw; unsigned long rate; if (attr->freq) { if (!attr->sample_freq) return -EINVAL; rate = getrate(attr->freq, attr->sample_freq, si); attr->freq = 0; /* Don't call perf_adjust_period() */ SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FREQ_MODE; } else { rate = getrate(attr->freq, attr->sample_period, si); if (!rate) return -EINVAL; } attr->sample_period = rate; SAMPL_RATE(hwc) = rate; hw_init_period(hwc, SAMPL_RATE(hwc)); debug_sprintf_event(sfdbg, 4, "%s: cpu %d period %#llx freq %d,%#lx\n", __func__, event->cpu, event->attr.sample_period, event->attr.freq, SAMPLE_FREQ_MODE(hwc)); return 0; } static int __hw_perf_event_init(struct perf_event *event) { struct cpu_hw_sf *cpuhw; struct hws_qsi_info_block si; struct perf_event_attr *attr = &event->attr; struct hw_perf_event *hwc = &event->hw; int cpu, err; /* Reserve CPU-measurement sampling facility */ err = 0; if (!atomic_inc_not_zero(&num_events)) { mutex_lock(&pmc_reserve_mutex); if (atomic_read(&num_events) == 0 && reserve_pmc_hardware()) err = -EBUSY; else atomic_inc(&num_events); mutex_unlock(&pmc_reserve_mutex); } event->destroy = hw_perf_event_destroy; if (err) goto out; /* Access per-CPU sampling information (query sampling info) */ /* * The event->cpu value can be -1 to count on every CPU, for example, * when attaching to a task. If this is specified, use the query * sampling info from the current CPU, otherwise use event->cpu to * retrieve the per-CPU information. * Later, cpuhw indicates whether to allocate sampling buffers for a * particular CPU (cpuhw!=NULL) or each online CPU (cpuw==NULL). */ memset(&si, 0, sizeof(si)); cpuhw = NULL; if (event->cpu == -1) qsi(&si); else { /* Event is pinned to a particular CPU, retrieve the per-CPU * sampling structure for accessing the CPU-specific QSI. */ cpuhw = &per_cpu(cpu_hw_sf, event->cpu); si = cpuhw->qsi; } /* Check sampling facility authorization and, if not authorized, * fall back to other PMUs. It is safe to check any CPU because * the authorization is identical for all configured CPUs. */ if (!si.as) { err = -ENOENT; goto out; } if (si.ribm & CPU_MF_SF_RIBM_NOTAV) { pr_warn("CPU Measurement Facility sampling is temporarily not available\n"); err = -EBUSY; goto out; } /* Always enable basic sampling */ SAMPL_FLAGS(hwc) = PERF_CPUM_SF_BASIC_MODE; /* Check if diagnostic sampling is requested. Deny if the required * sampling authorization is missing. */ if (attr->config == PERF_EVENT_CPUM_SF_DIAG) { if (!si.ad) { err = -EPERM; goto out; } SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_DIAG_MODE; } /* Check and set other sampling flags */ if (attr->config1 & PERF_CPUM_SF_FULL_BLOCKS) SAMPL_FLAGS(hwc) |= PERF_CPUM_SF_FULL_BLOCKS; err = __hw_perf_event_init_rate(event, &si); if (err) goto out; /* Initialize sample data overflow accounting */ hwc->extra_reg.reg = REG_OVERFLOW; OVERFLOW_REG(hwc) = 0; /* Use AUX buffer. No need to allocate it by ourself */ if (attr->config == PERF_EVENT_CPUM_SF_DIAG) return 0; /* Allocate the per-CPU sampling buffer using the CPU information * from the event. If the event is not pinned to a particular * CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling * buffers for each online CPU. */ if (cpuhw) /* Event is pinned to a particular CPU */ err = allocate_buffers(cpuhw, hwc); else { /* Event is not pinned, allocate sampling buffer on * each online CPU */ for_each_online_cpu(cpu) { cpuhw = &per_cpu(cpu_hw_sf, cpu); err = allocate_buffers(cpuhw, hwc); if (err) break; } } /* If PID/TID sampling is active, replace the default overflow * handler to extract and resolve the PIDs from the basic-sampling * data entries. */ if (event->attr.sample_type & PERF_SAMPLE_TID) if (is_default_overflow_handler(event)) event->overflow_handler = cpumsf_output_event_pid; out: return err; } static bool is_callchain_event(struct perf_event *event) { u64 sample_type = event->attr.sample_type; return sample_type & (PERF_SAMPLE_CALLCHAIN | PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER); } static int cpumsf_pmu_event_init(struct perf_event *event) { int err; /* No support for taken branch sampling */ /* No support for callchain, stacks and registers */ if (has_branch_stack(event) || is_callchain_event(event)) return -EOPNOTSUPP; switch (event->attr.type) { case PERF_TYPE_RAW: if ((event->attr.config != PERF_EVENT_CPUM_SF) && (event->attr.config != PERF_EVENT_CPUM_SF_DIAG)) return -ENOENT; break; case PERF_TYPE_HARDWARE: /* Support sampling of CPU cycles in addition to the * counter facility. However, the counter facility * is more precise and, hence, restrict this PMU to * sampling events only. */ if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES) return -ENOENT; if (!is_sampling_event(event)) return -ENOENT; break; default: return -ENOENT; } /* Check online status of the CPU to which the event is pinned */ if (event->cpu >= 0 && !cpu_online(event->cpu)) return -ENODEV; /* Force reset of idle/hv excludes regardless of what the * user requested. */ if (event->attr.exclude_hv) event->attr.exclude_hv = 0; if (event->attr.exclude_idle) event->attr.exclude_idle = 0; err = __hw_perf_event_init(event); if (unlikely(err)) if (event->destroy) event->destroy(event); return err; } static void cpumsf_pmu_enable(struct pmu *pmu) { struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); struct hw_perf_event *hwc; int err; if (cpuhw->flags & PMU_F_ENABLED) return; if (cpuhw->flags & PMU_F_ERR_MASK) return; /* Check whether to extent the sampling buffer. * * Two conditions trigger an increase of the sampling buffer for a * perf event: * 1. Postponed buffer allocations from the event initialization. * 2. Sampling overflows that contribute to pending allocations. * * Note that the extend_sampling_buffer() function disables the sampling * facility, but it can be fully re-enabled using sampling controls that * have been saved in cpumsf_pmu_disable(). */ if (cpuhw->event) { hwc = &cpuhw->event->hw; if (!(SAMPL_DIAG_MODE(hwc))) { /* * Account number of overflow-designated * buffer extents */ sfb_account_overflows(cpuhw, hwc); extend_sampling_buffer(&cpuhw->sfb, hwc); } /* Rate may be adjusted with ioctl() */ cpuhw->lsctl.interval = SAMPL_RATE(&cpuhw->event->hw); } /* (Re)enable the PMU and sampling facility */ cpuhw->flags |= PMU_F_ENABLED; barrier(); err = lsctl(&cpuhw->lsctl); if (err) { cpuhw->flags &= ~PMU_F_ENABLED; pr_err("Loading sampling controls failed: op %i err %i\n", 1, err); return; } /* Load current program parameter */ lpp(&S390_lowcore.lpp); debug_sprintf_event(sfdbg, 6, "%s: es %i cs %i ed %i cd %i " "interval %#lx tear %#lx dear %#lx\n", __func__, cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed, cpuhw->lsctl.cd, cpuhw->lsctl.interval, cpuhw->lsctl.tear, cpuhw->lsctl.dear); } static void cpumsf_pmu_disable(struct pmu *pmu) { struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); struct hws_lsctl_request_block inactive; struct hws_qsi_info_block si; int err; if (!(cpuhw->flags & PMU_F_ENABLED)) return; if (cpuhw->flags & PMU_F_ERR_MASK) return; /* Switch off sampling activation control */ inactive = cpuhw->lsctl; inactive.cs = 0; inactive.cd = 0; err = lsctl(&inactive); if (err) { pr_err("Loading sampling controls failed: op %i err %i\n", 2, err); return; } /* Save state of TEAR and DEAR register contents */ err = qsi(&si); if (!err) { /* TEAR/DEAR values are valid only if the sampling facility is * enabled. Note that cpumsf_pmu_disable() might be called even * for a disabled sampling facility because cpumsf_pmu_enable() * controls the enable/disable state. */ if (si.es) { cpuhw->lsctl.tear = si.tear; cpuhw->lsctl.dear = si.dear; } } else debug_sprintf_event(sfdbg, 3, "%s: qsi() failed with err %i\n", __func__, err); cpuhw->flags &= ~PMU_F_ENABLED; } /* perf_exclude_event() - Filter event * @event: The perf event * @regs: pt_regs structure * @sde_regs: Sample-data-entry (sde) regs structure * * Filter perf events according to their exclude specification. * * Return non-zero if the event shall be excluded. */ static int perf_exclude_event(struct perf_event *event, struct pt_regs *regs, struct perf_sf_sde_regs *sde_regs) { if (event->attr.exclude_user && user_mode(regs)) return 1; if (event->attr.exclude_kernel && !user_mode(regs)) return 1; if (event->attr.exclude_guest && sde_regs->in_guest) return 1; if (event->attr.exclude_host && !sde_regs->in_guest) return 1; return 0; } /* perf_push_sample() - Push samples to perf * @event: The perf event * @sample: Hardware sample data * * Use the hardware sample data to create perf event sample. The sample * is the pushed to the event subsystem and the function checks for * possible event overflows. If an event overflow occurs, the PMU is * stopped. * * Return non-zero if an event overflow occurred. */ static int perf_push_sample(struct perf_event *event, struct hws_basic_entry *basic) { int overflow; struct pt_regs regs; struct perf_sf_sde_regs *sde_regs; struct perf_sample_data data; /* Setup perf sample */ perf_sample_data_init(&data, 0, event->hw.last_period); /* Setup pt_regs to look like an CPU-measurement external interrupt * using the Program Request Alert code. The regs.int_parm_long * field which is unused contains additional sample-data-entry related * indicators. */ memset(®s, 0, sizeof(regs)); regs.int_code = 0x1407; regs.int_parm = CPU_MF_INT_SF_PRA; sde_regs = (struct perf_sf_sde_regs *) ®s.int_parm_long; psw_bits(regs.psw).ia = basic->ia; psw_bits(regs.psw).dat = basic->T; psw_bits(regs.psw).wait = basic->W; psw_bits(regs.psw).pstate = basic->P; psw_bits(regs.psw).as = basic->AS; /* * Use the hardware provided configuration level to decide if the * sample belongs to a guest or host. If that is not available, * fall back to the following heuristics: * A non-zero guest program parameter always indicates a guest * sample. Some early samples or samples from guests without * lpp usage would be misaccounted to the host. We use the asn * value as an addon heuristic to detect most of these guest samples. * If the value differs from 0xffff (the host value), we assume to * be a KVM guest. */ switch (basic->CL) { case 1: /* logical partition */ sde_regs->in_guest = 0; break; case 2: /* virtual machine */ sde_regs->in_guest = 1; break; default: /* old machine, use heuristics */ if (basic->gpp || basic->prim_asn != 0xffff) sde_regs->in_guest = 1; break; } /* * Store the PID value from the sample-data-entry to be * processed and resolved by cpumsf_output_event_pid(). */ data.tid_entry.pid = basic->hpp & LPP_PID_MASK; overflow = 0; if (perf_exclude_event(event, ®s, sde_regs)) goto out; if (perf_event_overflow(event, &data, ®s)) { overflow = 1; event->pmu->stop(event, 0); } perf_event_update_userpage(event); out: return overflow; } static void perf_event_count_update(struct perf_event *event, u64 count) { local64_add(count, &event->count); } /* hw_collect_samples() - Walk through a sample-data-block and collect samples * @event: The perf event * @sdbt: Sample-data-block table * @overflow: Event overflow counter * * Walks through a sample-data-block and collects sampling data entries that are * then pushed to the perf event subsystem. Depending on the sampling function, * there can be either basic-sampling or combined-sampling data entries. A * combined-sampling data entry consists of a basic- and a diagnostic-sampling * data entry. The sampling function is determined by the flags in the perf * event hardware structure. The function always works with a combined-sampling * data entry but ignores the the diagnostic portion if it is not available. * * Note that the implementation focuses on basic-sampling data entries and, if * such an entry is not valid, the entire combined-sampling data entry is * ignored. * * The overflow variables counts the number of samples that has been discarded * due to a perf event overflow. */ static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt, unsigned long long *overflow) { struct hws_trailer_entry *te; struct hws_basic_entry *sample; te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); sample = (struct hws_basic_entry *) *sdbt; while ((unsigned long *) sample < (unsigned long *) te) { /* Check for an empty sample */ if (!sample->def || sample->LS) break; /* Update perf event period */ perf_event_count_update(event, SAMPL_RATE(&event->hw)); /* Check whether sample is valid */ if (sample->def == 0x0001) { /* If an event overflow occurred, the PMU is stopped to * throttle event delivery. Remaining sample data is * discarded. */ if (!*overflow) { /* Check whether sample is consistent */ if (sample->I == 0 && sample->W == 0) { /* Deliver sample data to perf */ *overflow = perf_push_sample(event, sample); } } else /* Count discarded samples */ *overflow += 1; } else { debug_sprintf_event(sfdbg, 4, "%s: Found unknown" " sampling data entry: te->f %i" " basic.def %#4x (%p)\n", __func__, te->header.f, sample->def, sample); /* Sample slot is not yet written or other record. * * This condition can occur if the buffer was reused * from a combined basic- and diagnostic-sampling. * If only basic-sampling is then active, entries are * written into the larger diagnostic entries. * This is typically the case for sample-data-blocks * that are not full. Stop processing if the first * invalid format was detected. */ if (!te->header.f) break; } /* Reset sample slot and advance to next sample */ sample->def = 0; sample++; } } static inline __uint128_t __cdsg(__uint128_t *ptr, __uint128_t old, __uint128_t new) { asm volatile( " cdsg %[old],%[new],%[ptr]\n" : [old] "+d" (old), [ptr] "+QS" (*ptr) : [new] "d" (new) : "memory", "cc"); return old; } /* hw_perf_event_update() - Process sampling buffer * @event: The perf event * @flush_all: Flag to also flush partially filled sample-data-blocks * * Processes the sampling buffer and create perf event samples. * The sampling buffer position are retrieved and saved in the TEAR_REG * register of the specified perf event. * * Only full sample-data-blocks are processed. Specify the flash_all flag * to also walk through partially filled sample-data-blocks. It is ignored * if PERF_CPUM_SF_FULL_BLOCKS is set. The PERF_CPUM_SF_FULL_BLOCKS flag * enforces the processing of full sample-data-blocks only (trailer entries * with the block-full-indicator bit set). */ static void hw_perf_event_update(struct perf_event *event, int flush_all) { unsigned long long event_overflow, sampl_overflow, num_sdb; union hws_trailer_header old, prev, new; struct hw_perf_event *hwc = &event->hw; struct hws_trailer_entry *te; unsigned long *sdbt; int done; /* * AUX buffer is used when in diagnostic sampling mode. * No perf events/samples are created. */ if (SAMPL_DIAG_MODE(&event->hw)) return; if (flush_all && SDB_FULL_BLOCKS(hwc)) flush_all = 0; sdbt = (unsigned long *) TEAR_REG(hwc); done = event_overflow = sampl_overflow = num_sdb = 0; while (!done) { /* Get the trailer entry of the sample-data-block */ te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); /* Leave loop if no more work to do (block full indicator) */ if (!te->header.f) { done = 1; if (!flush_all) break; } /* Check the sample overflow count */ if (te->header.overflow) /* Account sample overflows and, if a particular limit * is reached, extend the sampling buffer. * For details, see sfb_account_overflows(). */ sampl_overflow += te->header.overflow; /* Timestamps are valid for full sample-data-blocks only */ debug_sprintf_event(sfdbg, 6, "%s: sdbt %#lx " "overflow %llu timestamp %#llx\n", __func__, (unsigned long)sdbt, te->header.overflow, (te->header.f) ? trailer_timestamp(te) : 0ULL); /* Collect all samples from a single sample-data-block and * flag if an (perf) event overflow happened. If so, the PMU * is stopped and remaining samples will be discarded. */ hw_collect_samples(event, sdbt, &event_overflow); num_sdb++; /* Reset trailer (using compare-double-and-swap) */ /* READ_ONCE() 16 byte header */ prev.val = __cdsg(&te->header.val, 0, 0); do { old.val = prev.val; new.val = prev.val; new.f = 0; new.a = 1; new.overflow = 0; prev.val = __cdsg(&te->header.val, old.val, new.val); } while (prev.val != old.val); /* Advance to next sample-data-block */ sdbt++; if (is_link_entry(sdbt)) sdbt = get_next_sdbt(sdbt); /* Update event hardware registers */ TEAR_REG(hwc) = (unsigned long) sdbt; /* Stop processing sample-data if all samples of the current * sample-data-block were flushed even if it was not full. */ if (flush_all && done) break; } /* Account sample overflows in the event hardware structure */ if (sampl_overflow) OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) + sampl_overflow, 1 + num_sdb); /* Perf_event_overflow() and perf_event_account_interrupt() limit * the interrupt rate to an upper limit. Roughly 1000 samples per * task tick. * Hitting this limit results in a large number * of throttled REF_REPORT_THROTTLE entries and the samples * are dropped. * Slightly increase the interval to avoid hitting this limit. */ if (event_overflow) { SAMPL_RATE(hwc) += DIV_ROUND_UP(SAMPL_RATE(hwc), 10); debug_sprintf_event(sfdbg, 1, "%s: rate adjustment %ld\n", __func__, DIV_ROUND_UP(SAMPL_RATE(hwc), 10)); } if (sampl_overflow || event_overflow) debug_sprintf_event(sfdbg, 4, "%s: " "overflows: sample %llu event %llu" " total %llu num_sdb %llu\n", __func__, sampl_overflow, event_overflow, OVERFLOW_REG(hwc), num_sdb); } #define AUX_SDB_INDEX(aux, i) ((i) % aux->sfb.num_sdb) #define AUX_SDB_NUM(aux, start, end) (end >= start ? end - start + 1 : 0) #define AUX_SDB_NUM_ALERT(aux) AUX_SDB_NUM(aux, aux->head, aux->alert_mark) #define AUX_SDB_NUM_EMPTY(aux) AUX_SDB_NUM(aux, aux->head, aux->empty_mark) /* * Get trailer entry by index of SDB. */ static struct hws_trailer_entry *aux_sdb_trailer(struct aux_buffer *aux, unsigned long index) { unsigned long sdb; index = AUX_SDB_INDEX(aux, index); sdb = aux->sdb_index[index]; return (struct hws_trailer_entry *)trailer_entry_ptr(sdb); } /* * Finish sampling on the cpu. Called by cpumsf_pmu_del() with pmu * disabled. Collect the full SDBs in AUX buffer which have not reached * the point of alert indicator. And ignore the SDBs which are not * full. * * 1. Scan SDBs to see how much data is there and consume them. * 2. Remove alert indicator in the buffer. */ static void aux_output_end(struct perf_output_handle *handle) { unsigned long i, range_scan, idx; struct aux_buffer *aux; struct hws_trailer_entry *te; aux = perf_get_aux(handle); if (!aux) return; range_scan = AUX_SDB_NUM_ALERT(aux); for (i = 0, idx = aux->head; i < range_scan; i++, idx++) { te = aux_sdb_trailer(aux, idx); if (!te->header.f) break; } /* i is num of SDBs which are full */ perf_aux_output_end(handle, i << PAGE_SHIFT); /* Remove alert indicators in the buffer */ te = aux_sdb_trailer(aux, aux->alert_mark); te->header.a = 0; debug_sprintf_event(sfdbg, 6, "%s: SDBs %ld range %ld head %ld\n", __func__, i, range_scan, aux->head); } /* * Start sampling on the CPU. Called by cpumsf_pmu_add() when an event * is first added to the CPU or rescheduled again to the CPU. It is called * with pmu disabled. * * 1. Reset the trailer of SDBs to get ready for new data. * 2. Tell the hardware where to put the data by reset the SDBs buffer * head(tear/dear). */ static int aux_output_begin(struct perf_output_handle *handle, struct aux_buffer *aux, struct cpu_hw_sf *cpuhw) { unsigned long range; unsigned long i, range_scan, idx; unsigned long head, base, offset; struct hws_trailer_entry *te; if (WARN_ON_ONCE(handle->head & ~PAGE_MASK)) return -EINVAL; aux->head = handle->head >> PAGE_SHIFT; range = (handle->size + 1) >> PAGE_SHIFT; if (range <= 1) return -ENOMEM; /* * SDBs between aux->head and aux->empty_mark are already ready * for new data. range_scan is num of SDBs not within them. */ debug_sprintf_event(sfdbg, 6, "%s: range %ld head %ld alert %ld empty %ld\n", __func__, range, aux->head, aux->alert_mark, aux->empty_mark); if (range > AUX_SDB_NUM_EMPTY(aux)) { range_scan = range - AUX_SDB_NUM_EMPTY(aux); idx = aux->empty_mark + 1; for (i = 0; i < range_scan; i++, idx++) { te = aux_sdb_trailer(aux, idx); te->header.f = 0; te->header.a = 0; te->header.overflow = 0; } /* Save the position of empty SDBs */ aux->empty_mark = aux->head + range - 1; } /* Set alert indicator */ aux->alert_mark = aux->head + range/2 - 1; te = aux_sdb_trailer(aux, aux->alert_mark); te->header.a = 1; /* Reset hardware buffer head */ head = AUX_SDB_INDEX(aux, aux->head); base = aux->sdbt_index[head / CPUM_SF_SDB_PER_TABLE]; offset = head % CPUM_SF_SDB_PER_TABLE; cpuhw->lsctl.tear = base + offset * sizeof(unsigned long); cpuhw->lsctl.dear = aux->sdb_index[head]; debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld empty %ld " "index %ld tear %#lx dear %#lx\n", __func__, aux->head, aux->alert_mark, aux->empty_mark, head / CPUM_SF_SDB_PER_TABLE, cpuhw->lsctl.tear, cpuhw->lsctl.dear); return 0; } /* * Set alert indicator on SDB at index @alert_index while sampler is running. * * Return true if successfully. * Return false if full indicator is already set by hardware sampler. */ static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, unsigned long long *overflow) { union hws_trailer_header old, prev, new; struct hws_trailer_entry *te; te = aux_sdb_trailer(aux, alert_index); /* READ_ONCE() 16 byte header */ prev.val = __cdsg(&te->header.val, 0, 0); do { old.val = prev.val; new.val = prev.val; *overflow = old.overflow; if (old.f) { /* * SDB is already set by hardware. * Abort and try to set somewhere * behind. */ return false; } new.a = 1; new.overflow = 0; prev.val = __cdsg(&te->header.val, old.val, new.val); } while (prev.val != old.val); return true; } /* * aux_reset_buffer() - Scan and setup SDBs for new samples * @aux: The AUX buffer to set * @range: The range of SDBs to scan started from aux->head * @overflow: Set to overflow count * * Set alert indicator on the SDB at index of aux->alert_mark. If this SDB is * marked as empty, check if it is already set full by the hardware sampler. * If yes, that means new data is already there before we can set an alert * indicator. Caller should try to set alert indicator to some position behind. * * Scan the SDBs in AUX buffer from behind aux->empty_mark. They are used * previously and have already been consumed by user space. Reset these SDBs * (clear full indicator and alert indicator) for new data. * If aux->alert_mark fall in this area, just set it. Overflow count is * recorded while scanning. * * SDBs between aux->head and aux->empty_mark are already reset at last time. * and ready for new samples. So scanning on this area could be skipped. * * Return true if alert indicator is set successfully and false if not. */ static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, unsigned long long *overflow) { unsigned long i, range_scan, idx, idx_old; union hws_trailer_header old, prev, new; unsigned long long orig_overflow; struct hws_trailer_entry *te; debug_sprintf_event(sfdbg, 6, "%s: range %ld head %ld alert %ld " "empty %ld\n", __func__, range, aux->head, aux->alert_mark, aux->empty_mark); if (range <= AUX_SDB_NUM_EMPTY(aux)) /* * No need to scan. All SDBs in range are marked as empty. * Just set alert indicator. Should check race with hardware * sampler. */ return aux_set_alert(aux, aux->alert_mark, overflow); if (aux->alert_mark <= aux->empty_mark) /* * Set alert indicator on empty SDB. Should check race * with hardware sampler. */ if (!aux_set_alert(aux, aux->alert_mark, overflow)) return false; /* * Scan the SDBs to clear full and alert indicator used previously. * Start scanning from one SDB behind empty_mark. If the new alert * indicator fall into this range, set it. */ range_scan = range - AUX_SDB_NUM_EMPTY(aux); idx_old = idx = aux->empty_mark + 1; for (i = 0; i < range_scan; i++, idx++) { te = aux_sdb_trailer(aux, idx); /* READ_ONCE() 16 byte header */ prev.val = __cdsg(&te->header.val, 0, 0); do { old.val = prev.val; new.val = prev.val; orig_overflow = old.overflow; new.f = 0; new.overflow = 0; if (idx == aux->alert_mark) new.a = 1; else new.a = 0; prev.val = __cdsg(&te->header.val, old.val, new.val); } while (prev.val != old.val); *overflow += orig_overflow; } /* Update empty_mark to new position */ aux->empty_mark = aux->head + range - 1; debug_sprintf_event(sfdbg, 6, "%s: range_scan %ld idx %ld..%ld " "empty %ld\n", __func__, range_scan, idx_old, idx - 1, aux->empty_mark); return true; } /* * Measurement alert handler for diagnostic mode sampling. */ static void hw_collect_aux(struct cpu_hw_sf *cpuhw) { struct aux_buffer *aux; int done = 0; unsigned long range = 0, size; unsigned long long overflow = 0; struct perf_output_handle *handle = &cpuhw->handle; unsigned long num_sdb; aux = perf_get_aux(handle); if (WARN_ON_ONCE(!aux)) return; /* Inform user space new data arrived */ size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; debug_sprintf_event(sfdbg, 6, "%s: #alert %ld\n", __func__, size >> PAGE_SHIFT); perf_aux_output_end(handle, size); num_sdb = aux->sfb.num_sdb; while (!done) { /* Get an output handle */ aux = perf_aux_output_begin(handle, cpuhw->event); if (handle->size == 0) { pr_err("The AUX buffer with %lu pages for the " "diagnostic-sampling mode is full\n", num_sdb); debug_sprintf_event(sfdbg, 1, "%s: AUX buffer used up\n", __func__); break; } if (WARN_ON_ONCE(!aux)) return; /* Update head and alert_mark to new position */ aux->head = handle->head >> PAGE_SHIFT; range = (handle->size + 1) >> PAGE_SHIFT; if (range == 1) aux->alert_mark = aux->head; else aux->alert_mark = aux->head + range/2 - 1; if (aux_reset_buffer(aux, range, &overflow)) { if (!overflow) { done = 1; break; } size = range << PAGE_SHIFT; perf_aux_output_end(&cpuhw->handle, size); pr_err("Sample data caused the AUX buffer with %lu " "pages to overflow\n", aux->sfb.num_sdb); debug_sprintf_event(sfdbg, 1, "%s: head %ld range %ld " "overflow %lld\n", __func__, aux->head, range, overflow); } else { size = AUX_SDB_NUM_ALERT(aux) << PAGE_SHIFT; perf_aux_output_end(&cpuhw->handle, size); debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " "already full, try another\n", __func__, aux->head, aux->alert_mark); } } if (done) debug_sprintf_event(sfdbg, 6, "%s: head %ld alert %ld " "empty %ld\n", __func__, aux->head, aux->alert_mark, aux->empty_mark); } /* * Callback when freeing AUX buffers. */ static void aux_buffer_free(void *data) { struct aux_buffer *aux = data; unsigned long i, num_sdbt; if (!aux) return; /* Free SDBT. SDB is freed by the caller */ num_sdbt = aux->sfb.num_sdbt; for (i = 0; i < num_sdbt; i++) free_page(aux->sdbt_index[i]); kfree(aux->sdbt_index); kfree(aux->sdb_index); kfree(aux); debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu\n", __func__, num_sdbt); } static void aux_sdb_init(unsigned long sdb) { struct hws_trailer_entry *te; te = (struct hws_trailer_entry *)trailer_entry_ptr(sdb); /* Save clock base */ te->clock_base = 1; te->progusage2 = tod_clock_base.tod; } /* * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling * @event: Event the buffer is setup for, event->cpu == -1 means current * @pages: Array of pointers to buffer pages passed from perf core * @nr_pages: Total pages * @snapshot: Flag for snapshot mode * * This is the callback when setup an event using AUX buffer. Perf tool can * trigger this by an additional mmap() call on the event. Unlike the buffer * for basic samples, AUX buffer belongs to the event. It is scheduled with * the task among online cpus when it is a per-thread event. * * Return the private AUX buffer structure if success or NULL if fails. */ static void *aux_buffer_setup(struct perf_event *event, void **pages, int nr_pages, bool snapshot) { struct sf_buffer *sfb; struct aux_buffer *aux; unsigned long *new, *tail; int i, n_sdbt; if (!nr_pages || !pages) return NULL; if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) { pr_err("AUX buffer size (%i pages) is larger than the " "maximum sampling buffer limit\n", nr_pages); return NULL; } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) { pr_err("AUX buffer size (%i pages) is less than the " "minimum sampling buffer limit\n", nr_pages); return NULL; } /* Allocate aux_buffer struct for the event */ aux = kzalloc(sizeof(struct aux_buffer), GFP_KERNEL); if (!aux) goto no_aux; sfb = &aux->sfb; /* Allocate sdbt_index for fast reference */ n_sdbt = DIV_ROUND_UP(nr_pages, CPUM_SF_SDB_PER_TABLE); aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL); if (!aux->sdbt_index) goto no_sdbt_index; /* Allocate sdb_index for fast reference */ aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL); if (!aux->sdb_index) goto no_sdb_index; /* Allocate the first SDBT */ sfb->num_sdbt = 0; sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL); if (!sfb->sdbt) goto no_sdbt; aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt; tail = sfb->tail = sfb->sdbt; /* * Link the provided pages of AUX buffer to SDBT. * Allocate SDBT if needed. */ for (i = 0; i < nr_pages; i++, tail++) { if (require_table_link(tail)) { new = (unsigned long *) get_zeroed_page(GFP_KERNEL); if (!new) goto no_sdbt; aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new; /* Link current page to tail of chain */ *tail = (unsigned long)(void *) new + 1; tail = new; } /* Tail is the entry in a SDBT */ *tail = (unsigned long)pages[i]; aux->sdb_index[i] = (unsigned long)pages[i]; aux_sdb_init((unsigned long)pages[i]); } sfb->num_sdb = nr_pages; /* Link the last entry in the SDBT to the first SDBT */ *tail = (unsigned long) sfb->sdbt + 1; sfb->tail = tail; /* * Initial all SDBs are zeroed. Mark it as empty. * So there is no need to clear the full indicator * when this event is first added. */ aux->empty_mark = sfb->num_sdb - 1; debug_sprintf_event(sfdbg, 4, "%s: SDBTs %lu SDBs %lu\n", __func__, sfb->num_sdbt, sfb->num_sdb); return aux; no_sdbt: /* SDBs (AUX buffer pages) are freed by caller */ for (i = 0; i < sfb->num_sdbt; i++) free_page(aux->sdbt_index[i]); kfree(aux->sdb_index); no_sdb_index: kfree(aux->sdbt_index); no_sdbt_index: kfree(aux); no_aux: return NULL; } static void cpumsf_pmu_read(struct perf_event *event) { /* Nothing to do ... updates are interrupt-driven */ } /* Check if the new sampling period/freqeuncy is appropriate. * * Return non-zero on error and zero on passed checks. */ static int cpumsf_pmu_check_period(struct perf_event *event, u64 value) { struct hws_qsi_info_block si; unsigned long rate; bool do_freq; memset(&si, 0, sizeof(si)); if (event->cpu == -1) { if (qsi(&si)) return -ENODEV; } else { /* Event is pinned to a particular CPU, retrieve the per-CPU * sampling structure for accessing the CPU-specific QSI. */ struct cpu_hw_sf *cpuhw = &per_cpu(cpu_hw_sf, event->cpu); si = cpuhw->qsi; } do_freq = !!SAMPLE_FREQ_MODE(&event->hw); rate = getrate(do_freq, value, &si); if (!rate) return -EINVAL; event->attr.sample_period = rate; SAMPL_RATE(&event->hw) = rate; hw_init_period(&event->hw, SAMPL_RATE(&event->hw)); debug_sprintf_event(sfdbg, 4, "%s:" " cpu %d value %#llx period %#llx freq %d\n", __func__, event->cpu, value, event->attr.sample_period, do_freq); return 0; } /* Activate sampling control. * Next call of pmu_enable() starts sampling. */ static void cpumsf_pmu_start(struct perf_event *event, int flags) { struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED))) return; if (flags & PERF_EF_RELOAD) WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); perf_pmu_disable(event->pmu); event->hw.state = 0; cpuhw->lsctl.cs = 1; if (SAMPL_DIAG_MODE(&event->hw)) cpuhw->lsctl.cd = 1; perf_pmu_enable(event->pmu); } /* Deactivate sampling control. * Next call of pmu_enable() stops sampling. */ static void cpumsf_pmu_stop(struct perf_event *event, int flags) { struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); if (event->hw.state & PERF_HES_STOPPED) return; perf_pmu_disable(event->pmu); cpuhw->lsctl.cs = 0; cpuhw->lsctl.cd = 0; event->hw.state |= PERF_HES_STOPPED; if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { hw_perf_event_update(event, 1); event->hw.state |= PERF_HES_UPTODATE; } perf_pmu_enable(event->pmu); } static int cpumsf_pmu_add(struct perf_event *event, int flags) { struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); struct aux_buffer *aux; int err; if (cpuhw->flags & PMU_F_IN_USE) return -EAGAIN; if (!SAMPL_DIAG_MODE(&event->hw) && !cpuhw->sfb.sdbt) return -EINVAL; err = 0; perf_pmu_disable(event->pmu); event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; /* Set up sampling controls. Always program the sampling register * using the SDB-table start. Reset TEAR_REG event hardware register * that is used by hw_perf_event_update() to store the sampling buffer * position after samples have been flushed. */ cpuhw->lsctl.s = 0; cpuhw->lsctl.h = 1; cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); if (!SAMPL_DIAG_MODE(&event->hw)) { cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt; cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt; TEAR_REG(&event->hw) = (unsigned long) cpuhw->sfb.sdbt; } /* Ensure sampling functions are in the disabled state. If disabled, * switch on sampling enable control. */ if (WARN_ON_ONCE(cpuhw->lsctl.es == 1 || cpuhw->lsctl.ed == 1)) { err = -EAGAIN; goto out; } if (SAMPL_DIAG_MODE(&event->hw)) { aux = perf_aux_output_begin(&cpuhw->handle, event); if (!aux) { err = -EINVAL; goto out; } err = aux_output_begin(&cpuhw->handle, aux, cpuhw); if (err) goto out; cpuhw->lsctl.ed = 1; } cpuhw->lsctl.es = 1; /* Set in_use flag and store event */ cpuhw->event = event; cpuhw->flags |= PMU_F_IN_USE; if (flags & PERF_EF_START) cpumsf_pmu_start(event, PERF_EF_RELOAD); out: perf_event_update_userpage(event); perf_pmu_enable(event->pmu); return err; } static void cpumsf_pmu_del(struct perf_event *event, int flags) { struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf); perf_pmu_disable(event->pmu); cpumsf_pmu_stop(event, PERF_EF_UPDATE); cpuhw->lsctl.es = 0; cpuhw->lsctl.ed = 0; cpuhw->flags &= ~PMU_F_IN_USE; cpuhw->event = NULL; if (SAMPL_DIAG_MODE(&event->hw)) aux_output_end(&cpuhw->handle); perf_event_update_userpage(event); perf_pmu_enable(event->pmu); } CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC, PERF_EVENT_CPUM_SF); CPUMF_EVENT_ATTR(SF, SF_CYCLES_BASIC_DIAG, PERF_EVENT_CPUM_SF_DIAG); /* Attribute list for CPU_SF. * * The availablitiy depends on the CPU_MF sampling facility authorization * for basic + diagnositic samples. This is determined at initialization * time by the sampling facility device driver. * If the authorization for basic samples is turned off, it should be * also turned off for diagnostic sampling. * * During initialization of the device driver, check the authorization * level for diagnostic sampling and installs the attribute * file for diagnostic sampling if necessary. * * For now install a placeholder to reference all possible attributes: * SF_CYCLES_BASIC and SF_CYCLES_BASIC_DIAG. * Add another entry for the final NULL pointer. */ enum { SF_CYCLES_BASIC_ATTR_IDX = 0, SF_CYCLES_BASIC_DIAG_ATTR_IDX, SF_CYCLES_ATTR_MAX }; static struct attribute *cpumsf_pmu_events_attr[SF_CYCLES_ATTR_MAX + 1] = { [SF_CYCLES_BASIC_ATTR_IDX] = CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC) }; PMU_FORMAT_ATTR(event, "config:0-63"); static struct attribute *cpumsf_pmu_format_attr[] = { &format_attr_event.attr, NULL, }; static struct attribute_group cpumsf_pmu_events_group = { .name = "events", .attrs = cpumsf_pmu_events_attr, }; static struct attribute_group cpumsf_pmu_format_group = { .name = "format", .attrs = cpumsf_pmu_format_attr, }; static const struct attribute_group *cpumsf_pmu_attr_groups[] = { &cpumsf_pmu_events_group, &cpumsf_pmu_format_group, NULL, }; static struct pmu cpumf_sampling = { .pmu_enable = cpumsf_pmu_enable, .pmu_disable = cpumsf_pmu_disable, .event_init = cpumsf_pmu_event_init, .add = cpumsf_pmu_add, .del = cpumsf_pmu_del, .start = cpumsf_pmu_start, .stop = cpumsf_pmu_stop, .read = cpumsf_pmu_read, .attr_groups = cpumsf_pmu_attr_groups, .setup_aux = aux_buffer_setup, .free_aux = aux_buffer_free, .check_period = cpumsf_pmu_check_period, }; static void cpumf_measurement_alert(struct ext_code ext_code, unsigned int alert, unsigned long unused) { struct cpu_hw_sf *cpuhw; if (!(alert & CPU_MF_INT_SF_MASK)) return; inc_irq_stat(IRQEXT_CMS); cpuhw = this_cpu_ptr(&cpu_hw_sf); /* Measurement alerts are shared and might happen when the PMU * is not reserved. Ignore these alerts in this case. */ if (!(cpuhw->flags & PMU_F_RESERVED)) return; /* The processing below must take care of multiple alert events that * might be indicated concurrently. */ /* Program alert request */ if (alert & CPU_MF_INT_SF_PRA) { if (cpuhw->flags & PMU_F_IN_USE) if (SAMPL_DIAG_MODE(&cpuhw->event->hw)) hw_collect_aux(cpuhw); else hw_perf_event_update(cpuhw->event, 0); else WARN_ON_ONCE(!(cpuhw->flags & PMU_F_IN_USE)); } /* Report measurement alerts only for non-PRA codes */ if (alert != CPU_MF_INT_SF_PRA) debug_sprintf_event(sfdbg, 6, "%s: alert %#x\n", __func__, alert); /* Sampling authorization change request */ if (alert & CPU_MF_INT_SF_SACA) qsi(&cpuhw->qsi); /* Loss of sample data due to high-priority machine activities */ if (alert & CPU_MF_INT_SF_LSDA) { pr_err("Sample data was lost\n"); cpuhw->flags |= PMU_F_ERR_LSDA; sf_disable(); } /* Invalid sampling buffer entry */ if (alert & (CPU_MF_INT_SF_IAE|CPU_MF_INT_SF_ISE)) { pr_err("A sampling buffer entry is incorrect (alert=0x%x)\n", alert); cpuhw->flags |= PMU_F_ERR_IBE; sf_disable(); } } static int cpusf_pmu_setup(unsigned int cpu, int flags) { /* Ignore the notification if no events are scheduled on the PMU. * This might be racy... */ if (!atomic_read(&num_events)) return 0; local_irq_disable(); setup_pmc_cpu(&flags); local_irq_enable(); return 0; } static int s390_pmu_sf_online_cpu(unsigned int cpu) { return cpusf_pmu_setup(cpu, PMC_INIT); } static int s390_pmu_sf_offline_cpu(unsigned int cpu) { return cpusf_pmu_setup(cpu, PMC_RELEASE); } static int param_get_sfb_size(char *buffer, const struct kernel_param *kp) { if (!cpum_sf_avail()) return -ENODEV; return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); } static int param_set_sfb_size(const char *val, const struct kernel_param *kp) { int rc; unsigned long min, max; if (!cpum_sf_avail()) return -ENODEV; if (!val || !strlen(val)) return -EINVAL; /* Valid parameter values: "min,max" or "max" */ min = CPUM_SF_MIN_SDB; max = CPUM_SF_MAX_SDB; if (strchr(val, ',')) rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL; else rc = kstrtoul(val, 10, &max); if (min < 2 || min >= max || max > get_num_physpages()) rc = -EINVAL; if (rc) return rc; sfb_set_limits(min, max); pr_info("The sampling buffer limits have changed to: " "min %lu max %lu (diag %lu)\n", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB, CPUM_SF_SDB_DIAG_FACTOR); return 0; } #define param_check_sfb_size(name, p) __param_check(name, p, void) static const struct kernel_param_ops param_ops_sfb_size = { .set = param_set_sfb_size, .get = param_get_sfb_size, }; #define RS_INIT_FAILURE_QSI 0x0001 #define RS_INIT_FAILURE_BSDES 0x0002 #define RS_INIT_FAILURE_ALRT 0x0003 #define RS_INIT_FAILURE_PERF 0x0004 static void __init pr_cpumsf_err(unsigned int reason) { pr_err("Sampling facility support for perf is not available: " "reason %#x\n", reason); } static int __init init_cpum_sampling_pmu(void) { struct hws_qsi_info_block si; int err; if (!cpum_sf_avail()) return -ENODEV; memset(&si, 0, sizeof(si)); if (qsi(&si)) { pr_cpumsf_err(RS_INIT_FAILURE_QSI); return -ENODEV; } if (!si.as && !si.ad) return -ENODEV; if (si.bsdes != sizeof(struct hws_basic_entry)) { pr_cpumsf_err(RS_INIT_FAILURE_BSDES); return -EINVAL; } if (si.ad) { sfb_set_limits(CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB); /* Sampling of diagnostic data authorized, * install event into attribute list of PMU device. */ cpumsf_pmu_events_attr[SF_CYCLES_BASIC_DIAG_ATTR_IDX] = CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC_DIAG); } sfdbg = debug_register(KMSG_COMPONENT, 2, 1, 80); if (!sfdbg) { pr_err("Registering for s390dbf failed\n"); return -ENOMEM; } debug_register_view(sfdbg, &debug_sprintf_view); err = register_external_irq(EXT_IRQ_MEASURE_ALERT, cpumf_measurement_alert); if (err) { pr_cpumsf_err(RS_INIT_FAILURE_ALRT); debug_unregister(sfdbg); goto out; } err = perf_pmu_register(&cpumf_sampling, "cpum_sf", PERF_TYPE_RAW); if (err) { pr_cpumsf_err(RS_INIT_FAILURE_PERF); unregister_external_irq(EXT_IRQ_MEASURE_ALERT, cpumf_measurement_alert); debug_unregister(sfdbg); goto out; } cpuhp_setup_state(CPUHP_AP_PERF_S390_SF_ONLINE, "perf/s390/sf:online", s390_pmu_sf_online_cpu, s390_pmu_sf_offline_cpu); out: return err; } arch_initcall(init_cpum_sampling_pmu); core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0644);
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