#undef DEBUG /* * ARM performance counter support. * * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles * Copyright (C) 2010 ARM Ltd., Will Deacon * * This code is based on the sparc64 perf event code, which is in turn based * on the x86 code. */ #define pr_fmt(fmt) "hw perfevents: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include static int armpmu_map_cache_event(const unsigned (*cache_map) [PERF_COUNT_HW_CACHE_MAX] [PERF_COUNT_HW_CACHE_OP_MAX] [PERF_COUNT_HW_CACHE_RESULT_MAX], u64 config) { unsigned int cache_type, cache_op, cache_result, ret; cache_type = (config >> 0) & 0xff; if (cache_type >= PERF_COUNT_HW_CACHE_MAX) return -EINVAL; cache_op = (config >> 8) & 0xff; if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX) return -EINVAL; cache_result = (config >> 16) & 0xff; if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX) return -EINVAL; if (!cache_map) return -ENOENT; ret = (int)(*cache_map)[cache_type][cache_op][cache_result]; if (ret == CACHE_OP_UNSUPPORTED) return -ENOENT; return ret; } static int armpmu_map_hw_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config) { int mapping; if (config >= PERF_COUNT_HW_MAX) return -EINVAL; if (!event_map) return -ENOENT; mapping = (*event_map)[config]; return mapping == HW_OP_UNSUPPORTED ? -ENOENT : mapping; } static int armpmu_map_raw_event(u32 raw_event_mask, u64 config) { return (int)(config & raw_event_mask); } int armpmu_map_event(struct perf_event *event, const unsigned (*event_map)[PERF_COUNT_HW_MAX], const unsigned (*cache_map) [PERF_COUNT_HW_CACHE_MAX] [PERF_COUNT_HW_CACHE_OP_MAX] [PERF_COUNT_HW_CACHE_RESULT_MAX], u32 raw_event_mask) { u64 config = event->attr.config; int type = event->attr.type; if (type == event->pmu->type) return armpmu_map_raw_event(raw_event_mask, config); switch (type) { case PERF_TYPE_HARDWARE: return armpmu_map_hw_event(event_map, config); case PERF_TYPE_HW_CACHE: return armpmu_map_cache_event(cache_map, config); case PERF_TYPE_RAW: return armpmu_map_raw_event(raw_event_mask, config); } return -ENOENT; } int armpmu_event_set_period(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; s64 left = local64_read(&hwc->period_left); s64 period = hwc->sample_period; int ret = 0; if (unlikely(left <= -period)) { left = period; local64_set(&hwc->period_left, left); hwc->last_period = period; ret = 1; } if (unlikely(left <= 0)) { left += period; local64_set(&hwc->period_left, left); hwc->last_period = period; ret = 1; } /* * Limit the maximum period to prevent the counter value * from overtaking the one we are about to program. In * effect we are reducing max_period to account for * interrupt latency (and we are being very conservative). */ if (left > (armpmu->max_period >> 1)) left = armpmu->max_period >> 1; local64_set(&hwc->prev_count, (u64)-left); armpmu->write_counter(event, (u64)(-left) & 0xffffffff); perf_event_update_userpage(event); return ret; } u64 armpmu_event_update(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; u64 delta, prev_raw_count, new_raw_count; again: prev_raw_count = local64_read(&hwc->prev_count); new_raw_count = armpmu->read_counter(event); if (local64_cmpxchg(&hwc->prev_count, prev_raw_count, new_raw_count) != prev_raw_count) goto again; delta = (new_raw_count - prev_raw_count) & armpmu->max_period; local64_add(delta, &event->count); local64_sub(delta, &hwc->period_left); return new_raw_count; } static void armpmu_read(struct perf_event *event) { armpmu_event_update(event); } static void armpmu_stop(struct perf_event *event, int flags) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; /* * ARM pmu always has to update the counter, so ignore * PERF_EF_UPDATE, see comments in armpmu_start(). */ if (!(hwc->state & PERF_HES_STOPPED)) { armpmu->disable(event); armpmu_event_update(event); hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE; } } static void armpmu_start(struct perf_event *event, int flags) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; /* * ARM pmu always has to reprogram the period, so ignore * PERF_EF_RELOAD, see the comment below. */ if (flags & PERF_EF_RELOAD) WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE)); hwc->state = 0; /* * Set the period again. Some counters can't be stopped, so when we * were stopped we simply disabled the IRQ source and the counter * may have been left counting. If we don't do this step then we may * get an interrupt too soon or *way* too late if the overflow has * happened since disabling. */ armpmu_event_set_period(event); armpmu->enable(event); } static void armpmu_del(struct perf_event *event, int flags) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; armpmu_stop(event, PERF_EF_UPDATE); hw_events->events[idx] = NULL; clear_bit(idx, hw_events->used_mask); if (armpmu->clear_event_idx) armpmu->clear_event_idx(hw_events, event); perf_event_update_userpage(event); } static int armpmu_add(struct perf_event *event, int flags) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); struct hw_perf_event *hwc = &event->hw; int idx; /* An event following a process won't be stopped earlier */ if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus)) return -ENOENT; /* If we don't have a space for the counter then finish early. */ idx = armpmu->get_event_idx(hw_events, event); if (idx < 0) return idx; /* * If there is an event in the counter we are going to use then make * sure it is disabled. */ event->hw.idx = idx; armpmu->disable(event); hw_events->events[idx] = event; hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE; if (flags & PERF_EF_START) armpmu_start(event, PERF_EF_RELOAD); /* Propagate our changes to the userspace mapping. */ perf_event_update_userpage(event); return 0; } static int validate_event(struct pmu *pmu, struct pmu_hw_events *hw_events, struct perf_event *event) { struct arm_pmu *armpmu; if (is_software_event(event)) return 1; /* * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The * core perf code won't check that the pmu->ctx == leader->ctx * until after pmu->event_init(event). */ if (event->pmu != pmu) return 0; if (event->state < PERF_EVENT_STATE_OFF) return 1; if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec) return 1; armpmu = to_arm_pmu(event->pmu); return armpmu->get_event_idx(hw_events, event) >= 0; } static int validate_group(struct perf_event *event) { struct perf_event *sibling, *leader = event->group_leader; struct pmu_hw_events fake_pmu; /* * Initialise the fake PMU. We only need to populate the * used_mask for the purposes of validation. */ memset(&fake_pmu.used_mask, 0, sizeof(fake_pmu.used_mask)); if (!validate_event(event->pmu, &fake_pmu, leader)) return -EINVAL; list_for_each_entry(sibling, &leader->sibling_list, group_entry) { if (!validate_event(event->pmu, &fake_pmu, sibling)) return -EINVAL; } if (!validate_event(event->pmu, &fake_pmu, event)) return -EINVAL; return 0; } static struct arm_pmu_platdata *armpmu_get_platdata(struct arm_pmu *armpmu) { struct platform_device *pdev = armpmu->plat_device; return pdev ? dev_get_platdata(&pdev->dev) : NULL; } static irqreturn_t armpmu_dispatch_irq(int irq, void *dev) { struct arm_pmu *armpmu; struct arm_pmu_platdata *plat; int ret; u64 start_clock, finish_clock; /* * we request the IRQ with a (possibly percpu) struct arm_pmu**, but * the handlers expect a struct arm_pmu*. The percpu_irq framework will * do any necessary shifting, we just need to perform the first * dereference. */ armpmu = *(void **)dev; plat = armpmu_get_platdata(armpmu); start_clock = sched_clock(); if (plat && plat->handle_irq) ret = plat->handle_irq(irq, armpmu, armpmu->handle_irq); else ret = armpmu->handle_irq(irq, armpmu); finish_clock = sched_clock(); perf_sample_event_took(finish_clock - start_clock); return ret; } static int event_requires_mode_exclusion(struct perf_event_attr *attr) { return attr->exclude_idle || attr->exclude_user || attr->exclude_kernel || attr->exclude_hv; } static int __hw_perf_event_init(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; int mapping; mapping = armpmu->map_event(event); if (mapping < 0) { pr_debug("event %x:%llx not supported\n", event->attr.type, event->attr.config); return mapping; } /* * We don't assign an index until we actually place the event onto * hardware. Use -1 to signify that we haven't decided where to put it * yet. For SMP systems, each core has it's own PMU so we can't do any * clever allocation or constraints checking at this point. */ hwc->idx = -1; hwc->config_base = 0; hwc->config = 0; hwc->event_base = 0; /* * Check whether we need to exclude the counter from certain modes. */ if ((!armpmu->set_event_filter || armpmu->set_event_filter(hwc, &event->attr)) && event_requires_mode_exclusion(&event->attr)) { pr_debug("ARM performance counters do not support " "mode exclusion\n"); return -EOPNOTSUPP; } /* * Store the event encoding into the config_base field. */ hwc->config_base |= (unsigned long)mapping; if (!is_sampling_event(event)) { /* * For non-sampling runs, limit the sample_period to half * of the counter width. That way, the new counter value * is far less likely to overtake the previous one unless * you have some serious IRQ latency issues. */ hwc->sample_period = armpmu->max_period >> 1; hwc->last_period = hwc->sample_period; local64_set(&hwc->period_left, hwc->sample_period); } if (event->group_leader != event) { if (validate_group(event) != 0) return -EINVAL; } return 0; } static int armpmu_event_init(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); /* * Reject CPU-affine events for CPUs that are of a different class to * that which this PMU handles. Process-following events (where * event->cpu == -1) can be migrated between CPUs, and thus we have to * reject them later (in armpmu_add) if they're scheduled on a * different class of CPU. */ if (event->cpu != -1 && !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus)) return -ENOENT; /* does not support taken branch sampling */ if (has_branch_stack(event)) return -EOPNOTSUPP; if (armpmu->map_event(event) == -ENOENT) return -ENOENT; return __hw_perf_event_init(event); } static void armpmu_enable(struct pmu *pmu) { struct arm_pmu *armpmu = to_arm_pmu(pmu); struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events); /* For task-bound events we may be called on other CPUs */ if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus)) return; if (enabled) armpmu->start(armpmu); } static void armpmu_disable(struct pmu *pmu) { struct arm_pmu *armpmu = to_arm_pmu(pmu); /* For task-bound events we may be called on other CPUs */ if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus)) return; armpmu->stop(armpmu); } /* * In heterogeneous systems, events are specific to a particular * microarchitecture, and aren't suitable for another. Thus, only match CPUs of * the same microarchitecture. */ static int armpmu_filter_match(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); unsigned int cpu = smp_processor_id(); return cpumask_test_cpu(cpu, &armpmu->supported_cpus); } static ssize_t armpmu_cpumask_show(struct device *dev, struct device_attribute *attr, char *buf) { struct arm_pmu *armpmu = to_arm_pmu(dev_get_drvdata(dev)); return cpumap_print_to_pagebuf(true, buf, &armpmu->supported_cpus); } static DEVICE_ATTR(cpus, S_IRUGO, armpmu_cpumask_show, NULL); static struct attribute *armpmu_common_attrs[] = { &dev_attr_cpus.attr, NULL, }; static struct attribute_group armpmu_common_attr_group = { .attrs = armpmu_common_attrs, }; /* Set at runtime when we know what CPU type we are. */ static struct arm_pmu *__oprofile_cpu_pmu; /* * Despite the names, these two functions are CPU-specific and are used * by the OProfile/perf code. */ const char *perf_pmu_name(void) { if (!__oprofile_cpu_pmu) return NULL; return __oprofile_cpu_pmu->name; } EXPORT_SYMBOL_GPL(perf_pmu_name); int perf_num_counters(void) { int max_events = 0; if (__oprofile_cpu_pmu != NULL) max_events = __oprofile_cpu_pmu->num_events; return max_events; } EXPORT_SYMBOL_GPL(perf_num_counters); void armpmu_free_irq(struct arm_pmu *armpmu, int cpu) { struct pmu_hw_events __percpu *hw_events = armpmu->hw_events; int irq = per_cpu(hw_events->irq, cpu); if (!cpumask_test_and_clear_cpu(cpu, &armpmu->active_irqs)) return; if (irq_is_percpu(irq)) { free_percpu_irq(irq, &hw_events->percpu_pmu); cpumask_clear(&armpmu->active_irqs); return; } free_irq(irq, per_cpu_ptr(&hw_events->percpu_pmu, cpu)); } void armpmu_free_irqs(struct arm_pmu *armpmu) { int cpu; for_each_cpu(cpu, &armpmu->supported_cpus) armpmu_free_irq(armpmu, cpu); } int armpmu_request_irq(struct arm_pmu *armpmu, int cpu) { int err = 0; struct pmu_hw_events __percpu *hw_events = armpmu->hw_events; const irq_handler_t handler = armpmu_dispatch_irq; int irq = per_cpu(hw_events->irq, cpu); if (!irq) return 0; if (irq_is_percpu(irq) && cpumask_empty(&armpmu->active_irqs)) { err = request_percpu_irq(irq, handler, "arm-pmu", &hw_events->percpu_pmu); } else if (irq_is_percpu(irq)) { int other_cpu = cpumask_first(&armpmu->active_irqs); int other_irq = per_cpu(hw_events->irq, other_cpu); if (irq != other_irq) { pr_warn("mismatched PPIs detected.\n"); err = -EINVAL; goto err_out; } } else { struct arm_pmu_platdata *platdata = armpmu_get_platdata(armpmu); unsigned long irq_flags; err = irq_force_affinity(irq, cpumask_of(cpu)); if (err && num_possible_cpus() > 1) { pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n", irq, cpu); goto err_out; } if (platdata && platdata->irq_flags) { irq_flags = platdata->irq_flags; } else { irq_flags = IRQF_PERCPU | IRQF_NOBALANCING | IRQF_NO_THREAD; } err = request_irq(irq, handler, irq_flags, "arm-pmu", per_cpu_ptr(&hw_events->percpu_pmu, cpu)); } if (err) goto err_out; cpumask_set_cpu(cpu, &armpmu->active_irqs); return 0; err_out: pr_err("unable to request IRQ%d for ARM PMU counters\n", irq); return err; } int armpmu_request_irqs(struct arm_pmu *armpmu) { int cpu, err; for_each_cpu(cpu, &armpmu->supported_cpus) { err = armpmu_request_irq(armpmu, cpu); if (err) break; } return err; } static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu) { struct pmu_hw_events __percpu *hw_events = pmu->hw_events; return per_cpu(hw_events->irq, cpu); } /* * PMU hardware loses all context when a CPU goes offline. * When a CPU is hotplugged back in, since some hardware registers are * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading * junk values out of them. */ static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node) { struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node); int irq; if (!cpumask_test_cpu(cpu, &pmu->supported_cpus)) return 0; if (pmu->reset) pmu->reset(pmu); irq = armpmu_get_cpu_irq(pmu, cpu); if (irq) { if (irq_is_percpu(irq)) { enable_percpu_irq(irq, IRQ_TYPE_NONE); return 0; } } return 0; } static int arm_perf_teardown_cpu(unsigned int cpu, struct hlist_node *node) { struct arm_pmu *pmu = hlist_entry_safe(node, struct arm_pmu, node); int irq; if (!cpumask_test_cpu(cpu, &pmu->supported_cpus)) return 0; irq = armpmu_get_cpu_irq(pmu, cpu); if (irq && irq_is_percpu(irq)) disable_percpu_irq(irq); return 0; } #ifdef CONFIG_CPU_PM static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd) { struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); struct perf_event *event; int idx; for (idx = 0; idx < armpmu->num_events; idx++) { /* * If the counter is not used skip it, there is no * need of stopping/restarting it. */ if (!test_bit(idx, hw_events->used_mask)) continue; event = hw_events->events[idx]; switch (cmd) { case CPU_PM_ENTER: /* * Stop and update the counter */ armpmu_stop(event, PERF_EF_UPDATE); break; case CPU_PM_EXIT: case CPU_PM_ENTER_FAILED: /* * Restore and enable the counter. * armpmu_start() indirectly calls * * perf_event_update_userpage() * * that requires RCU read locking to be functional, * wrap the call within RCU_NONIDLE to make the * RCU subsystem aware this cpu is not idle from * an RCU perspective for the armpmu_start() call * duration. */ RCU_NONIDLE(armpmu_start(event, PERF_EF_RELOAD)); break; default: break; } } } static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd, void *v) { struct arm_pmu *armpmu = container_of(b, struct arm_pmu, cpu_pm_nb); struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events); if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus)) return NOTIFY_DONE; /* * Always reset the PMU registers on power-up even if * there are no events running. */ if (cmd == CPU_PM_EXIT && armpmu->reset) armpmu->reset(armpmu); if (!enabled) return NOTIFY_OK; switch (cmd) { case CPU_PM_ENTER: armpmu->stop(armpmu); cpu_pm_pmu_setup(armpmu, cmd); break; case CPU_PM_EXIT: cpu_pm_pmu_setup(armpmu, cmd); case CPU_PM_ENTER_FAILED: armpmu->start(armpmu); break; default: return NOTIFY_DONE; } return NOTIFY_OK; } static int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu) { cpu_pmu->cpu_pm_nb.notifier_call = cpu_pm_pmu_notify; return cpu_pm_register_notifier(&cpu_pmu->cpu_pm_nb); } static void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) { cpu_pm_unregister_notifier(&cpu_pmu->cpu_pm_nb); } #else static inline int cpu_pm_pmu_register(struct arm_pmu *cpu_pmu) { return 0; } static inline void cpu_pm_pmu_unregister(struct arm_pmu *cpu_pmu) { } #endif static int cpu_pmu_init(struct arm_pmu *cpu_pmu) { int err; err = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_STARTING, &cpu_pmu->node); if (err) goto out; err = cpu_pm_pmu_register(cpu_pmu); if (err) goto out_unregister; return 0; out_unregister: cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING, &cpu_pmu->node); out: return err; } static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu) { cpu_pm_pmu_unregister(cpu_pmu); cpuhp_state_remove_instance_nocalls(CPUHP_AP_PERF_ARM_STARTING, &cpu_pmu->node); } struct arm_pmu *armpmu_alloc(void) { struct arm_pmu *pmu; int cpu; pmu = kzalloc(sizeof(*pmu), GFP_KERNEL); if (!pmu) { pr_info("failed to allocate PMU device!\n"); goto out; } pmu->hw_events = alloc_percpu(struct pmu_hw_events); if (!pmu->hw_events) { pr_info("failed to allocate per-cpu PMU data.\n"); goto out_free_pmu; } pmu->pmu = (struct pmu) { .pmu_enable = armpmu_enable, .pmu_disable = armpmu_disable, .event_init = armpmu_event_init, .add = armpmu_add, .del = armpmu_del, .start = armpmu_start, .stop = armpmu_stop, .read = armpmu_read, .filter_match = armpmu_filter_match, .attr_groups = pmu->attr_groups, /* * This is a CPU PMU potentially in a heterogeneous * configuration (e.g. big.LITTLE). This is not an uncore PMU, * and we have taken ctx sharing into account (e.g. with our * pmu::filter_match callback and pmu::event_init group * validation). */ .capabilities = PERF_PMU_CAP_HETEROGENEOUS_CPUS, }; pmu->attr_groups[ARMPMU_ATTR_GROUP_COMMON] = &armpmu_common_attr_group; for_each_possible_cpu(cpu) { struct pmu_hw_events *events; events = per_cpu_ptr(pmu->hw_events, cpu); raw_spin_lock_init(&events->pmu_lock); events->percpu_pmu = pmu; } return pmu; out_free_pmu: kfree(pmu); out: return NULL; } void armpmu_free(struct arm_pmu *pmu) { free_percpu(pmu->hw_events); kfree(pmu); } int armpmu_register(struct arm_pmu *pmu) { int ret; ret = cpu_pmu_init(pmu); if (ret) return ret; ret = perf_pmu_register(&pmu->pmu, pmu->name, -1); if (ret) goto out_destroy; if (!__oprofile_cpu_pmu) __oprofile_cpu_pmu = pmu; pr_info("enabled with %s PMU driver, %d counters available\n", pmu->name, pmu->num_events); return 0; out_destroy: cpu_pmu_destroy(pmu); return ret; } static int arm_pmu_hp_init(void) { int ret; ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_STARTING, "perf/arm/pmu:starting", arm_perf_starting_cpu, arm_perf_teardown_cpu); if (ret) pr_err("CPU hotplug notifier for ARM PMU could not be registered: %d\n", ret); return ret; } subsys_initcall(arm_pmu_hp_init);