/* * Performance event support for the System z CPU-measurement Sampling Facility * * Copyright IBM Corp. 2013 * Author(s): Hendrik Brueckner * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License (version 2 only) * as published by the Free Software Foundation. */ #define KMSG_COMPONENT "cpum_sf" #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include /* 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 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 */ }; 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, "free_sampling_buffer: freed sdbt=%p\n", sfb->sdbt); memset(sfb, 0, sizeof(*sfb)); } static int alloc_sample_data_block(unsigned long *sdbt, gfp_t gfp_flags) { unsigned long sdb, *trailer; /* Allocate and initialize sample-data-block */ sdb = get_zeroed_page(gfp_flags); if (!sdb) return -ENOMEM; trailer = trailer_entry_ptr(sdb); *trailer = SDB_TE_ALERT_REQ_MASK; /* 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, "realloc_sampling_buffer: " "sampling buffer is not linked: origin=%p" "tail=%p\n", (void *) sfb->sdbt, (void *) 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, "realloc_sampling_buffer: new buffer" " settings: sdbt=%lu sdb=%lu\n", 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, "alloc_sampling_buffer: " "realloc_sampling_buffer failed with rc=%i\n", rc); } else debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: tear=%p dear=%p\n", sfb->sdbt, (void *) *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 size_t event_sample_size(struct hw_perf_event *hwc) { struct sf_raw_sample *sfr = (struct sf_raw_sample *) RAWSAMPLE_REG(hwc); size_t sample_size; /* The sample size depends on the sampling function: The basic-sampling * function must be always enabled, diagnostic-sampling function is * optional. */ sample_size = sfr->bsdes; if (SAMPL_DIAG_MODE(hwc)) sample_size += sfr->dsdes; return sample_size; } 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, factor; size_t sfr_size, sample_size; struct sf_raw_sample *sfr; /* Allocate raw sample buffer * * The raw sample buffer is used to temporarily store sampling data * entries for perf raw sample processing. The buffer size mainly * depends on the size of diagnostic-sampling data entries which is * machine-specific. The exact size calculation includes: * 1. The first 4 bytes of diagnostic-sampling data entries are * already reflected in the sf_raw_sample structure. Subtract * these bytes. * 2. The perf raw sample data must be 8-byte aligned (u64) and * perf's internal data size must be considered too. So add * an additional u32 for correct alignment and subtract before * allocating the buffer. * 3. Store the raw sample buffer pointer in the perf event * hardware structure. */ sfr_size = ALIGN((sizeof(*sfr) - sizeof(sfr->diag) + cpuhw->qsi.dsdes) + sizeof(u32), sizeof(u64)); sfr_size -= sizeof(u32); sfr = kzalloc(sfr_size, GFP_KERNEL); if (!sfr) return -ENOMEM; sfr->size = sfr_size; sfr->bsdes = cpuhw->qsi.bsdes; sfr->dsdes = cpuhw->qsi.dsdes; RAWSAMPLE_REG(hwc) = (unsigned long) sfr; /* Calculate sampling buffers using 4K pages * * 1. Determine the sample data size which depends on the used * sampling functions, for example, basic-sampling or * basic-sampling with diagnostic-sampling. * * 2. Use the sampling frequency as input. The sampling buffer is * designed for almost one second. This can be adjusted through * the "factor" variable. * In any case, alloc_sampling_buffer() sets the Alert Request * Control indicator to trigger a measurement-alert to harvest * sample-data-blocks (sdb). * * 3. Compute the number of sample-data-blocks and ensure a minimum * of CPUM_SF_MIN_SDB. Also ensure the upper limit does not * exceed a "calculated" maximum. The symbolic maximum is * designed for basic-sampling only and needs to be increased if * diagnostic-sampling is active. * See also the remarks for these symbolic constants. * * 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 = event_sample_size(hwc); freq = sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc)); factor = 1; n_sdb = DIV_ROUND_UP(freq, factor * ((PAGE_SIZE-64) / sample_size)); if (n_sdb < CPUM_SF_MIN_SDB) n_sdb = CPUM_SF_MIN_SDB; /* 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, "allocate_buffers: rate=%lu f=%lu sdb=%lu/%lu" " sample_size=%lu cpuhw=%p\n", 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, "sfb: overflow: overflow=%llu ratio=%lu" " num=%lu\n", 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, "sfb: extend: realloc " "failed with rc=%i\n", rc); if (sfb_has_pending_allocs(sfb, hwc)) debug_sprintf_event(sfdbg, 5, "sfb: extend: " "req=%lu alloc=%lu remaining=%lu\n", 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, "setup_pmc_cpu: initialized: cpuhw=%p\n", 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, "setup_pmc_cpu: released: cpuhw=%p\n", 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); perf_release_sampling(); } static int reserve_pmc_hardware(void) { int flags = PMC_INIT; int err; err = perf_reserve_sampling(); if (err) return err; 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) { /* Free raw sample buffer */ if (RAWSAMPLE_REG(&event->hw)) kfree((void *) RAWSAMPLE_REG(&event->hw)); /* 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 void hw_reset_registers(struct hw_perf_event *hwc, unsigned long *sdbt_origin) { struct sf_raw_sample *sfr; /* (Re)set to first sample-data-block-table */ TEAR_REG(hwc) = (unsigned long) sdbt_origin; /* (Re)set raw sampling buffer register */ sfr = (struct sf_raw_sample *) RAWSAMPLE_REG(hwc); memset(&sfr->basic, 0, sizeof(sfr->basic)); memset(&sfr->diag, 0, sfr->dsdes); } 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 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; unsigned long rate; 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; } /* 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; /* 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. */ rate = 0; if (attr->freq) { if (!attr->sample_freq) { err = -EINVAL; goto out; } rate = freq_to_sample_rate(&si, attr->sample_freq); rate = hw_limit_rate(&si, rate); attr->freq = 0; attr->sample_period = 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, hwc->sample_period); /* 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) { err = -EINVAL; debug_sprintf_event(sfdbg, 1, "Sampling rate exceeds maximum perf sample rate\n"); goto out; } } SAMPL_RATE(hwc) = rate; hw_init_period(hwc, SAMPL_RATE(hwc)); /* Initialize sample data overflow accounting */ hwc->extra_reg.reg = REG_OVERFLOW; OVERFLOW_REG(hwc) = 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; } } out: return err; } static int cpumsf_pmu_event_init(struct perf_event *event) { int err; /* No support for taken branch sampling */ if (has_branch_stack(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 >= nr_cpumask_bits || (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; /* Account number of overflow-designated buffer extents */ sfb_account_overflows(cpuhw, hwc); if (sfb_has_pending_allocs(&cpuhw->sfb, hwc)) extend_sampling_buffer(&cpuhw->sfb, hwc); } /* (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; } debug_sprintf_event(sfdbg, 6, "pmu_enable: es=%i cs=%i ed=%i cd=%i " "tear=%p dear=%p\n", cpuhw->lsctl.es, cpuhw->lsctl.cs, cpuhw->lsctl.ed, cpuhw->lsctl.cd, (void *) cpuhw->lsctl.tear, (void *) 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 */ if (!qsi(&si)) { /* 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, "cpumsf_pmu_disable: " "qsi() failed with err=%i\n", 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 sf_raw_sample *sfr) { int overflow; struct pt_regs regs; struct perf_sf_sde_regs *sde_regs; struct perf_sample_data data; struct perf_raw_record raw; /* Setup perf sample */ perf_sample_data_init(&data, 0, event->hw.last_period); raw.size = sfr->size; raw.data = sfr; data.raw = &raw; /* 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; regs.psw.addr = sfr->basic.ia; if (sfr->basic.T) regs.psw.mask |= PSW_MASK_DAT; if (sfr->basic.W) regs.psw.mask |= PSW_MASK_WAIT; if (sfr->basic.P) regs.psw.mask |= PSW_MASK_PSTATE; switch (sfr->basic.AS) { case 0x0: regs.psw.mask |= PSW_ASC_PRIMARY; break; case 0x1: regs.psw.mask |= PSW_ASC_ACCREG; break; case 0x2: regs.psw.mask |= PSW_ASC_SECONDARY; break; case 0x3: regs.psw.mask |= PSW_ASC_HOME; break; } /* * A non-zero guest program parameter indicates a guest * sample. * Note that some early samples might be misaccounted to * the host. */ if (sfr->basic.gpp) sde_regs->in_guest = 1; 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); } static int sample_format_is_valid(struct hws_combined_entry *sample, unsigned int flags) { if (likely(flags & PERF_CPUM_SF_BASIC_MODE)) /* Only basic-sampling data entries with data-entry-format * version of 0x0001 can be processed. */ if (sample->basic.def != 0x0001) return 0; if (flags & PERF_CPUM_SF_DIAG_MODE) /* The data-entry-format number of diagnostic-sampling data * entries can vary. Because diagnostic data is just passed * through, do only a sanity check on the DEF. */ if (sample->diag.def < 0x8001) return 0; return 1; } static int sample_is_consistent(struct hws_combined_entry *sample, unsigned long flags) { /* This check applies only to basic-sampling data entries of potentially * combined-sampling data entries. Invalid entries cannot be processed * by the PMU and, thus, do not deliver an associated * diagnostic-sampling data entry. */ if (unlikely(!(flags & PERF_CPUM_SF_BASIC_MODE))) return 0; /* * Samples are skipped, if they are invalid or for which the * instruction address is not predictable, i.e., the wait-state bit is * set. */ if (sample->basic.I || sample->basic.W) return 0; return 1; } static void reset_sample_slot(struct hws_combined_entry *sample, unsigned long flags) { if (likely(flags & PERF_CPUM_SF_BASIC_MODE)) sample->basic.def = 0; if (flags & PERF_CPUM_SF_DIAG_MODE) sample->diag.def = 0; } static void sfr_store_sample(struct sf_raw_sample *sfr, struct hws_combined_entry *sample) { if (likely(sfr->format & PERF_CPUM_SF_BASIC_MODE)) sfr->basic = sample->basic; if (sfr->format & PERF_CPUM_SF_DIAG_MODE) memcpy(&sfr->diag, &sample->diag, sfr->dsdes); } static void debug_sample_entry(struct hws_combined_entry *sample, struct hws_trailer_entry *te, unsigned long flags) { debug_sprintf_event(sfdbg, 4, "hw_collect_samples: Found unknown " "sampling data entry: te->f=%i basic.def=%04x (%p)" " diag.def=%04x (%p)\n", te->f, sample->basic.def, &sample->basic, (flags & PERF_CPUM_SF_DIAG_MODE) ? sample->diag.def : 0xFFFF, (flags & PERF_CPUM_SF_DIAG_MODE) ? &sample->diag : NULL); } /* 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) { unsigned long flags = SAMPL_FLAGS(&event->hw); struct hws_combined_entry *sample; struct hws_trailer_entry *te; struct sf_raw_sample *sfr; size_t sample_size; /* Prepare and initialize raw sample data */ sfr = (struct sf_raw_sample *) RAWSAMPLE_REG(&event->hw); sfr->format = flags & PERF_CPUM_SF_MODE_MASK; sample_size = event_sample_size(&event->hw); te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt); sample = (struct hws_combined_entry *) *sdbt; while ((unsigned long *) sample < (unsigned long *) te) { /* Check for an empty sample */ if (!sample->basic.def) break; /* Update perf event period */ perf_event_count_update(event, SAMPL_RATE(&event->hw)); /* Check sampling data entry */ if (sample_format_is_valid(sample, flags)) { /* If an event overflow occurred, the PMU is stopped to * throttle event delivery. Remaining sample data is * discarded. */ if (!*overflow) { if (sample_is_consistent(sample, flags)) { /* Deliver sample data to perf */ sfr_store_sample(sfr, sample); *overflow = perf_push_sample(event, sfr); } } else /* Count discarded samples */ *overflow += 1; } else { debug_sample_entry(sample, te, flags); /* 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->f) break; } /* Reset sample slot and advance to next sample */ reset_sample_slot(sample, flags); sample += sample_size; } } /* 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) { struct hw_perf_event *hwc = &event->hw; struct hws_trailer_entry *te; unsigned long *sdbt; unsigned long long event_overflow, sampl_overflow, num_sdb, te_flags; int done; 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->f) { done = 1; if (!flush_all) break; } /* Check the sample overflow count */ if (te->overflow) /* Account sample overflows and, if a particular limit * is reached, extend the sampling buffer. * For details, see sfb_account_overflows(). */ sampl_overflow += te->overflow; /* Timestamps are valid for full sample-data-blocks only */ debug_sprintf_event(sfdbg, 6, "hw_perf_event_update: sdbt=%p " "overflow=%llu timestamp=0x%llx\n", sdbt, te->overflow, (te->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) */ do { te_flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK; te_flags |= SDB_TE_ALERT_REQ_MASK; } while (!cmpxchg_double(&te->flags, &te->overflow, te->flags, te->overflow, te_flags, 0ULL)); /* 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, "hw_perf_event_update: " "overflow stats: sample=%llu event=%llu\n", sampl_overflow, event_overflow); } static void cpumsf_pmu_read(struct perf_event *event) { /* Nothing to do ... updates are interrupt-driven */ } /* 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); int err; if (cpuhw->flags & PMU_F_IN_USE) return -EAGAIN; if (!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.tear = (unsigned long) cpuhw->sfb.sdbt; cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt; cpuhw->lsctl.interval = SAMPL_RATE(&event->hw); hw_reset_registers(&event->hw, 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; } cpuhw->lsctl.es = 1; if (SAMPL_DIAG_MODE(&event->hw)) cpuhw->lsctl.ed = 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; 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); static struct attribute *cpumsf_pmu_events_attr[] = { CPUMF_EVENT_PTR(SF, SF_CYCLES_BASIC), NULL, NULL, }; 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, }; 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) 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, "measurement alert: 0x%x\n", 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 cpumf_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long) hcpu; int flags; /* Ignore the notification if no events are scheduled on the PMU. * This might be racy... */ if (!atomic_read(&num_events)) return NOTIFY_OK; switch (action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: case CPU_ONLINE_FROZEN: flags = PMC_INIT; smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1); break; case CPU_DOWN_PREPARE: flags = PMC_RELEASE; smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1); break; default: break; } return NOTIFY_OK; } 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=x%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=%04x\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.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); cpumsf_pmu_events_attr[1] = 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; } perf_cpu_notifier(cpumf_pmu_notifier); out: return err; } arch_initcall(init_cpum_sampling_pmu); core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0644);