// SPDX-License-Identifier: GPL-2.0 /* * Performance event support for s390x - CPU-measurement Counter Facility * * Copyright IBM Corp. 2012, 2019 * Author(s): Hendrik Brueckner */ #define KMSG_COMPONENT "cpum_cf" #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt #include #include #include #include #include #include #include static enum cpumf_ctr_set get_counter_set(u64 event) { int set = CPUMF_CTR_SET_MAX; 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 < 288) set = CPUMF_CTR_SET_EXT; else if (event >= 448 && event < 496) set = CPUMF_CTR_SET_MT_DIAG; return set; } static int validate_ctr_version(const struct hw_perf_event *hwc) { struct cpu_cf_events *cpuhw; int err = 0; u16 mtdiag_ctl; cpuhw = &get_cpu_var(cpu_cf_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: if ((cpuhw->info.csvn >= 1 && cpuhw->info.csvn <= 5 && hwc->config > 79) || (cpuhw->info.csvn >= 6 && hwc->config > 83)) err = -EOPNOTSUPP; break; case CPUMF_CTR_SET_EXT: if (cpuhw->info.csvn < 1) err = -EOPNOTSUPP; if ((cpuhw->info.csvn == 1 && hwc->config > 159) || (cpuhw->info.csvn == 2 && hwc->config > 175) || (cpuhw->info.csvn >= 3 && cpuhw->info.csvn <= 5 && hwc->config > 255) || (cpuhw->info.csvn >= 6 && hwc->config > 287)) err = -EOPNOTSUPP; break; case CPUMF_CTR_SET_MT_DIAG: if (cpuhw->info.csvn <= 3) err = -EOPNOTSUPP; /* * MT-diagnostic counters are read-only. The counter set * is automatically enabled and activated on all CPUs with * multithreading (SMT). Deactivation of multithreading * also disables the counter set. State changes are ignored * by lcctl(). Because Linux controls SMT enablement through * a kernel parameter only, the counter set is either disabled * or enabled and active. * * Thus, the counters can only be used if SMT is on and the * counter set is enabled and active. */ mtdiag_ctl = cpumf_ctr_ctl[CPUMF_CTR_SET_MT_DIAG]; if (!((cpuhw->info.auth_ctl & mtdiag_ctl) && (cpuhw->info.enable_ctl & mtdiag_ctl) && (cpuhw->info.act_ctl & mtdiag_ctl))) err = -EOPNOTSUPP; break; } put_cpu_var(cpu_cf_events); return err; } static int validate_ctr_auth(const struct hw_perf_event *hwc) { struct cpu_cf_events *cpuhw; u64 ctrs_state; int err = 0; cpuhw = &get_cpu_var(cpu_cf_events); /* Check authorization for cpu counter sets. * If the particular CPU counter set is not authorized, * return with -ENOENT in order to fall back to other * PMUs that might suffice the event request. */ ctrs_state = cpumf_ctr_ctl[hwc->config_base]; if (!(ctrs_state & cpuhw->info.auth_ctl)) err = -ENOENT; put_cpu_var(cpu_cf_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_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_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_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_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); /* 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) __kernel_cpumcf_end(); 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, unsigned int type) { struct perf_event_attr *attr = &event->attr; struct hw_perf_event *hwc = &event->hw; enum cpumf_ctr_set set; int err = 0; u64 ev; switch (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: if (is_sampling_event(event)) /* No sampling support */ return -ENOENT; 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 -ENOENT; /* Obtain the counter set to which the specified counter belongs */ set = get_counter_set(ev); switch (set) { case CPUMF_CTR_SET_BASIC: case CPUMF_CTR_SET_USER: case CPUMF_CTR_SET_CRYPTO: case CPUMF_CTR_SET_EXT: case CPUMF_CTR_SET_MT_DIAG: /* * Use the hardware perf event structure to store the * counter number in the 'config' member and the counter * set number in the 'config_base'. The counter set number * is then later used to enable/disable the counter(s). */ hwc->config = ev; hwc->config_base = set; break; case CPUMF_CTR_SET_MAX: /* The counter could not be associated to a counter set */ return -EINVAL; }; /* 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 && __kernel_cpumcf_begin()) err = -EBUSY; else atomic_inc(&num_events); mutex_unlock(&pmc_reserve_mutex); } if (err) return err; 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) { unsigned int type = event->attr.type; int err; if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_RAW) err = __hw_perf_event_init(event, type); else if (event->pmu->type == type) /* Registered as unknown PMU */ err = __hw_perf_event_init(event, PERF_TYPE_RAW); else 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 void 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) return; } 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); } 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_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_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_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_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_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_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->txn_flags & PERF_PMU_TXN_ADD)) if (validate_ctr_auth(&event->hw)) return -ENOENT; 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_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_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. * * We only support PERF_PMU_TXN_ADD transactions. Save the * transaction flags but otherwise ignore non-PERF_PMU_TXN_ADD * transactions. */ static void cpumf_pmu_start_txn(struct pmu *pmu, unsigned int txn_flags) { struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); WARN_ON_ONCE(cpuhw->txn_flags); /* txn already in flight */ cpuhw->txn_flags = txn_flags; if (txn_flags & ~PERF_PMU_TXN_ADD) return; perf_pmu_disable(pmu); 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) { unsigned int txn_flags; struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */ txn_flags = cpuhw->txn_flags; cpuhw->txn_flags = 0; if (txn_flags & ~PERF_PMU_TXN_ADD) return; WARN_ON(cpuhw->tx_state != cpuhw->state); 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_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events); u64 state; WARN_ON_ONCE(!cpuhw->txn_flags); /* no txn in flight */ if (cpuhw->txn_flags & ~PERF_PMU_TXN_ADD) { cpuhw->txn_flags = 0; return 0; } /* 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 -ENOENT; cpuhw->txn_flags = 0; perf_pmu_enable(pmu); return 0; } /* Performance monitoring unit for s390x */ static struct pmu cpumf_pmu = { .task_ctx_nr = perf_sw_context, .capabilities = PERF_PMU_CAP_NO_INTERRUPT, .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 __init cpumf_pmu_init(void) { int rc; if (!kernel_cpumcf_avail()) return -ENODEV; cpumf_pmu.attr_groups = cpumf_cf_event_group(); rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", -1); if (rc) pr_err("Registering the cpum_cf PMU failed with rc=%i\n", rc); return rc; } subsys_initcall(cpumf_pmu_init);