/* * Performance event support for s390x - CPU-measurement Counter Facility * * Copyright IBM Corp. 2012 * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> * * 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_cf" #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/notifier.h> #include <linux/init.h> #include <linux/export.h> #include <asm/ctl_reg.h> #include <asm/irq.h> #include <asm/cpu_mf.h> /* CPU-measurement counter facility supports these CPU counter sets: * For CPU counter sets: * Basic counter set: 0-31 * Problem-state counter set: 32-63 * Crypto-activity counter set: 64-127 * Extented counter set: 128-159 */ enum cpumf_ctr_set { /* CPU counter sets */ CPUMF_CTR_SET_BASIC = 0, CPUMF_CTR_SET_USER = 1, CPUMF_CTR_SET_CRYPTO = 2, CPUMF_CTR_SET_EXT = 3, /* Maximum number of counter sets */ CPUMF_CTR_SET_MAX, }; #define CPUMF_LCCTL_ENABLE_SHIFT 16 #define CPUMF_LCCTL_ACTCTL_SHIFT 0 static const u64 cpumf_state_ctl[CPUMF_CTR_SET_MAX] = { [CPUMF_CTR_SET_BASIC] = 0x02, [CPUMF_CTR_SET_USER] = 0x04, [CPUMF_CTR_SET_CRYPTO] = 0x08, [CPUMF_CTR_SET_EXT] = 0x01, }; static void ctr_set_enable(u64 *state, int ctr_set) { *state |= cpumf_state_ctl[ctr_set] << CPUMF_LCCTL_ENABLE_SHIFT; } static void ctr_set_disable(u64 *state, int ctr_set) { *state &= ~(cpumf_state_ctl[ctr_set] << CPUMF_LCCTL_ENABLE_SHIFT); } static void ctr_set_start(u64 *state, int ctr_set) { *state |= cpumf_state_ctl[ctr_set] << CPUMF_LCCTL_ACTCTL_SHIFT; } static void ctr_set_stop(u64 *state, int ctr_set) { *state &= ~(cpumf_state_ctl[ctr_set] << CPUMF_LCCTL_ACTCTL_SHIFT); } /* Local CPUMF event structure */ struct cpu_hw_events { struct cpumf_ctr_info info; atomic_t ctr_set[CPUMF_CTR_SET_MAX]; u64 state, tx_state; unsigned int flags; }; static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .ctr_set = { [CPUMF_CTR_SET_BASIC] = ATOMIC_INIT(0), [CPUMF_CTR_SET_USER] = ATOMIC_INIT(0), [CPUMF_CTR_SET_CRYPTO] = ATOMIC_INIT(0), [CPUMF_CTR_SET_EXT] = ATOMIC_INIT(0), }, .state = 0, .flags = 0, }; static int get_counter_set(u64 event) { int set = -1; if (event < 32) set = CPUMF_CTR_SET_BASIC; else if (event < 64) set = CPUMF_CTR_SET_USER; else if (event < 128) set = CPUMF_CTR_SET_CRYPTO; else if (event < 160) set = CPUMF_CTR_SET_EXT; return set; } static int validate_event(const struct hw_perf_event *hwc) { switch (hwc->config_base) { case CPUMF_CTR_SET_BASIC: case CPUMF_CTR_SET_USER: case CPUMF_CTR_SET_CRYPTO: case CPUMF_CTR_SET_EXT: /* check for reserved counters */ if ((hwc->config >= 6 && hwc->config <= 31) || (hwc->config >= 38 && hwc->config <= 63) || (hwc->config >= 80 && hwc->config <= 127)) return -EOPNOTSUPP; break; default: return -EINVAL; } return 0; } static int validate_ctr_version(const struct hw_perf_event *hwc) { struct cpu_hw_events *cpuhw; int err = 0; cpuhw = &get_cpu_var(cpu_hw_events); /* check required version for counter sets */ switch (hwc->config_base) { case CPUMF_CTR_SET_BASIC: case CPUMF_CTR_SET_USER: if (cpuhw->info.cfvn < 1) err = -EOPNOTSUPP; break; case CPUMF_CTR_SET_CRYPTO: case CPUMF_CTR_SET_EXT: if (cpuhw->info.csvn < 1) err = -EOPNOTSUPP; break; } put_cpu_var(cpu_hw_events); return err; } static int validate_ctr_auth(const struct hw_perf_event *hwc) { struct cpu_hw_events *cpuhw; u64 ctrs_state; int err = 0; cpuhw = &get_cpu_var(cpu_hw_events); /* check authorization for cpu counter sets */ ctrs_state = cpumf_state_ctl[hwc->config_base]; if (!(ctrs_state & cpuhw->info.auth_ctl)) err = -EPERM; put_cpu_var(cpu_hw_events); return err; } /* * Change the CPUMF state to active. * Enable and activate the CPU-counter sets according * to the per-cpu control state. */ static void cpumf_pmu_enable(struct pmu *pmu) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); int err; if (cpuhw->flags & PMU_F_ENABLED) return; err = lcctl(cpuhw->state); if (err) { pr_err("Enabling the performance measuring unit " "failed with rc=%x\n", err); return; } cpuhw->flags |= PMU_F_ENABLED; } /* * Change the CPUMF state to inactive. * Disable and enable (inactive) the CPU-counter sets according * to the per-cpu control state. */ static void cpumf_pmu_disable(struct pmu *pmu) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); int err; u64 inactive; if (!(cpuhw->flags & PMU_F_ENABLED)) return; inactive = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1); err = lcctl(inactive); if (err) { pr_err("Disabling the performance measuring unit " "failed with rc=%x\n", err); return; } cpuhw->flags &= ~PMU_F_ENABLED; } /* Number of perf events counting hardware events */ static atomic_t num_events = ATOMIC_INIT(0); /* Used to avoid races in calling reserve/release_cpumf_hardware */ static DEFINE_MUTEX(pmc_reserve_mutex); /* CPU-measurement alerts for the counter facility */ static void cpumf_measurement_alert(struct ext_code ext_code, unsigned int alert, unsigned long unused) { struct cpu_hw_events *cpuhw; if (!(alert & CPU_MF_INT_CF_MASK)) return; kstat_cpu(smp_processor_id()).irqs[EXTINT_CMC]++; cpuhw = &__get_cpu_var(cpu_hw_events); /* 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; /* counter authorization change alert */ if (alert & CPU_MF_INT_CF_CACA) qctri(&cpuhw->info); /* loss of counter data alert */ if (alert & CPU_MF_INT_CF_LCDA) pr_err("CPU[%i] Counter data was lost\n", smp_processor_id()); } #define PMC_INIT 0 #define PMC_RELEASE 1 static void setup_pmc_cpu(void *flags) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); switch (*((int *) flags)) { case PMC_INIT: memset(&cpuhw->info, 0, sizeof(cpuhw->info)); qctri(&cpuhw->info); cpuhw->flags |= PMU_F_RESERVED; break; case PMC_RELEASE: cpuhw->flags &= ~PMU_F_RESERVED; break; } /* Disable CPU counter sets */ lcctl(0); } /* Initialize the CPU-measurement facility */ static int reserve_pmc_hardware(void) { int flags = PMC_INIT; on_each_cpu(setup_pmc_cpu, &flags, 1); measurement_alert_subclass_register(); return 0; } /* Release the CPU-measurement facility */ static void release_pmc_hardware(void) { int flags = PMC_RELEASE; on_each_cpu(setup_pmc_cpu, &flags, 1); measurement_alert_subclass_unregister(); } /* Release the PMU if event is the last perf event */ static void hw_perf_event_destroy(struct perf_event *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); } } /* CPUMF <-> perf event mappings for kernel+userspace (basic set) */ static const int cpumf_generic_events_basic[] = { [PERF_COUNT_HW_CPU_CYCLES] = 0, [PERF_COUNT_HW_INSTRUCTIONS] = 1, [PERF_COUNT_HW_CACHE_REFERENCES] = -1, [PERF_COUNT_HW_CACHE_MISSES] = -1, [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1, [PERF_COUNT_HW_BRANCH_MISSES] = -1, [PERF_COUNT_HW_BUS_CYCLES] = -1, }; /* CPUMF <-> perf event mappings for userspace (problem-state set) */ static const int cpumf_generic_events_user[] = { [PERF_COUNT_HW_CPU_CYCLES] = 32, [PERF_COUNT_HW_INSTRUCTIONS] = 33, [PERF_COUNT_HW_CACHE_REFERENCES] = -1, [PERF_COUNT_HW_CACHE_MISSES] = -1, [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = -1, [PERF_COUNT_HW_BRANCH_MISSES] = -1, [PERF_COUNT_HW_BUS_CYCLES] = -1, }; static int __hw_perf_event_init(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; struct hw_perf_event *hwc = &event->hw; int err; u64 ev; switch (attr->type) { case PERF_TYPE_RAW: /* Raw events are used to access counters directly, * hence do not permit excludes */ if (attr->exclude_kernel || attr->exclude_user || attr->exclude_hv) return -EOPNOTSUPP; ev = attr->config; break; case PERF_TYPE_HARDWARE: ev = attr->config; /* Count user space (problem-state) only */ if (!attr->exclude_user && attr->exclude_kernel) { if (ev >= ARRAY_SIZE(cpumf_generic_events_user)) return -EOPNOTSUPP; ev = cpumf_generic_events_user[ev]; /* No support for kernel space counters only */ } else if (!attr->exclude_kernel && attr->exclude_user) { return -EOPNOTSUPP; /* Count user and kernel space */ } else { if (ev >= ARRAY_SIZE(cpumf_generic_events_basic)) return -EOPNOTSUPP; ev = cpumf_generic_events_basic[ev]; } break; default: return -ENOENT; } if (ev == -1) return -ENOENT; if (ev >= PERF_CPUM_CF_MAX_CTR) return -EINVAL; /* The CPU measurement counter facility does not have any interrupts * to do sampling. Sampling must be provided by external means, * for example, by timers. */ if (hwc->sample_period) return -EINVAL; /* Use the hardware perf event structure to store the counter number * in 'config' member and the counter set to which the counter belongs * in the 'config_base'. The counter set (config_base) is then used * to enable/disable the counters. */ hwc->config = ev; hwc->config_base = get_counter_set(ev); /* Validate the counter that is assigned to this event. * Because the counter facility can use numerous counters at the * same time without constraints, it is not necessary to explicity * validate event groups (event->group_leader != event). */ err = validate_event(hwc); if (err) return err; /* Initialize for using the CPU-measurement counter facility */ 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; /* Finally, validate version and authorization of the counter set */ err = validate_ctr_auth(hwc); if (!err) err = validate_ctr_version(hwc); return err; } static int cpumf_pmu_event_init(struct perf_event *event) { int err; switch (event->attr.type) { case PERF_TYPE_HARDWARE: case PERF_TYPE_HW_CACHE: case PERF_TYPE_RAW: err = __hw_perf_event_init(event); break; default: return -ENOENT; } if (unlikely(err) && event->destroy) event->destroy(event); return err; } static int hw_perf_event_reset(struct perf_event *event) { u64 prev, new; int err; do { prev = local64_read(&event->hw.prev_count); err = ecctr(event->hw.config, &new); if (err) { if (err != 3) break; /* The counter is not (yet) available. This * might happen if the counter set to which * this counter belongs is in the disabled * state. */ new = 0; } } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev); return err; } static int hw_perf_event_update(struct perf_event *event) { u64 prev, new, delta; int err; do { prev = local64_read(&event->hw.prev_count); err = ecctr(event->hw.config, &new); if (err) goto out; } while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev); delta = (prev <= new) ? new - prev : (-1ULL - prev) + new + 1; /* overflow */ local64_add(delta, &event->count); out: return err; } static void cpumf_pmu_read(struct perf_event *event) { if (event->hw.state & PERF_HES_STOPPED) return; hw_perf_event_update(event); } static void cpumf_pmu_start(struct perf_event *event, int flags) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED))) return; if (WARN_ON_ONCE(hwc->config == -1)) return; if (flags & PERF_EF_RELOAD) WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE)); hwc->state = 0; /* (Re-)enable and activate the counter set */ ctr_set_enable(&cpuhw->state, hwc->config_base); ctr_set_start(&cpuhw->state, hwc->config_base); /* The counter set to which this counter belongs can be already active. * Because all counters in a set are active, the event->hw.prev_count * needs to be synchronized. At this point, the counter set can be in * the inactive or disabled state. */ hw_perf_event_reset(event); /* increment refcount for this counter set */ atomic_inc(&cpuhw->ctr_set[hwc->config_base]); } static void cpumf_pmu_stop(struct perf_event *event, int flags) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; if (!(hwc->state & PERF_HES_STOPPED)) { /* Decrement reference count for this counter set and if this * is the last used counter in the set, clear activation * control and set the counter set state to inactive. */ if (!atomic_dec_return(&cpuhw->ctr_set[hwc->config_base])) ctr_set_stop(&cpuhw->state, hwc->config_base); event->hw.state |= PERF_HES_STOPPED; } if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) { hw_perf_event_update(event); event->hw.state |= PERF_HES_UPTODATE; } } static int cpumf_pmu_add(struct perf_event *event, int flags) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); /* Check authorization for the counter set to which this * counter belongs. * For group events transaction, the authorization check is * done in cpumf_pmu_commit_txn(). */ if (!(cpuhw->flags & PERF_EVENT_TXN)) if (validate_ctr_auth(&event->hw)) return -EPERM; ctr_set_enable(&cpuhw->state, event->hw.config_base); event->hw.state = PERF_HES_UPTODATE | PERF_HES_STOPPED; if (flags & PERF_EF_START) cpumf_pmu_start(event, PERF_EF_RELOAD); perf_event_update_userpage(event); return 0; } static void cpumf_pmu_del(struct perf_event *event, int flags) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); cpumf_pmu_stop(event, PERF_EF_UPDATE); /* Check if any counter in the counter set is still used. If not used, * change the counter set to the disabled state. This also clears the * content of all counters in the set. * * When a new perf event has been added but not yet started, this can * clear enable control and resets all counters in a set. Therefore, * cpumf_pmu_start() always has to reenable a counter set. */ if (!atomic_read(&cpuhw->ctr_set[event->hw.config_base])) ctr_set_disable(&cpuhw->state, event->hw.config_base); perf_event_update_userpage(event); } /* * Start group events scheduling transaction. * Set flags to perform a single test at commit time. */ static void cpumf_pmu_start_txn(struct pmu *pmu) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); perf_pmu_disable(pmu); cpuhw->flags |= PERF_EVENT_TXN; cpuhw->tx_state = cpuhw->state; } /* * Stop and cancel a group events scheduling tranctions. * Assumes cpumf_pmu_del() is called for each successful added * cpumf_pmu_add() during the transaction. */ static void cpumf_pmu_cancel_txn(struct pmu *pmu) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); WARN_ON(cpuhw->tx_state != cpuhw->state); cpuhw->flags &= ~PERF_EVENT_TXN; perf_pmu_enable(pmu); } /* * Commit the group events scheduling transaction. On success, the * transaction is closed. On error, the transaction is kept open * until cpumf_pmu_cancel_txn() is called. */ static int cpumf_pmu_commit_txn(struct pmu *pmu) { struct cpu_hw_events *cpuhw = &__get_cpu_var(cpu_hw_events); u64 state; /* check if the updated state can be scheduled */ state = cpuhw->state & ~((1 << CPUMF_LCCTL_ENABLE_SHIFT) - 1); state >>= CPUMF_LCCTL_ENABLE_SHIFT; if ((state & cpuhw->info.auth_ctl) != state) return -EPERM; cpuhw->flags &= ~PERF_EVENT_TXN; perf_pmu_enable(pmu); return 0; } /* Performance monitoring unit for s390x */ static struct pmu cpumf_pmu = { .pmu_enable = cpumf_pmu_enable, .pmu_disable = cpumf_pmu_disable, .event_init = cpumf_pmu_event_init, .add = cpumf_pmu_add, .del = cpumf_pmu_del, .start = cpumf_pmu_start, .stop = cpumf_pmu_stop, .read = cpumf_pmu_read, .start_txn = cpumf_pmu_start_txn, .commit_txn = cpumf_pmu_commit_txn, .cancel_txn = cpumf_pmu_cancel_txn, }; static int __cpuinit cpumf_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (long) hcpu; int flags; switch (action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: 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 __init cpumf_pmu_init(void) { int rc; if (!cpum_cf_avail()) return -ENODEV; /* clear bit 15 of cr0 to unauthorize problem-state to * extract measurement counters */ ctl_clear_bit(0, 48); /* register handler for measurement-alert interruptions */ rc = register_external_interrupt(0x1407, cpumf_measurement_alert); if (rc) { pr_err("Registering for CPU-measurement alerts " "failed with rc=%i\n", rc); goto out; } rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", PERF_TYPE_RAW); if (rc) { pr_err("Registering the cpum_cf PMU failed with rc=%i\n", rc); unregister_external_interrupt(0x1407, cpumf_measurement_alert); goto out; } perf_cpu_notifier(cpumf_pmu_notifier); out: return rc; } early_initcall(cpumf_pmu_init);