#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. Callchain code is based on the ARM OProfile backtrace * code. */ #define pr_fmt(fmt) "hw perfevents: " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include /* * ARMv6 supports a maximum of 3 events, starting from index 0. If we add * another platform that supports more, we need to increase this to be the * largest of all platforms. * * ARMv7 supports up to 32 events: * cycle counter CCNT + 31 events counters CNT0..30. * Cortex-A8 has 1+4 counters, Cortex-A9 has 1+6 counters. */ #define ARMPMU_MAX_HWEVENTS 32 static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events); static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask); static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events); #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu)) /* Set at runtime when we know what CPU type we are. */ static struct arm_pmu *cpu_pmu; enum arm_perf_pmu_ids armpmu_get_pmu_id(void) { int id = -ENODEV; if (cpu_pmu != NULL) id = cpu_pmu->id; return id; } EXPORT_SYMBOL_GPL(armpmu_get_pmu_id); int armpmu_get_max_events(void) { int max_events = 0; if (cpu_pmu != NULL) max_events = cpu_pmu->num_events; return max_events; } EXPORT_SYMBOL_GPL(armpmu_get_max_events); int perf_num_counters(void) { return armpmu_get_max_events(); } EXPORT_SYMBOL_GPL(perf_num_counters); #define HW_OP_UNSUPPORTED 0xFFFF #define C(_x) \ PERF_COUNT_HW_CACHE_##_x #define CACHE_OP_UNSUPPORTED 0xFFFF 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; ret = (int)(*cache_map)[cache_type][cache_op][cache_result]; if (ret == CACHE_OP_UNSUPPORTED) return -ENOENT; return ret; } static int armpmu_map_event(const unsigned (*event_map)[PERF_COUNT_HW_MAX], u64 config) { int 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); } static int map_cpu_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; switch (event->attr.type) { case PERF_TYPE_HARDWARE: return armpmu_map_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 hw_perf_event *hwc, int idx) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); 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; } if (left > (s64)armpmu->max_period) left = armpmu->max_period; local64_set(&hwc->prev_count, (u64)-left); armpmu->write_counter(idx, (u64)(-left) & 0xffffffff); perf_event_update_userpage(event); return ret; } u64 armpmu_event_update(struct perf_event *event, struct hw_perf_event *hwc, int idx) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); u64 delta, prev_raw_count, new_raw_count; again: prev_raw_count = local64_read(&hwc->prev_count); new_raw_count = armpmu->read_counter(idx); 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) { struct hw_perf_event *hwc = &event->hw; /* Don't read disabled counters! */ if (hwc->idx < 0) return; armpmu_event_update(event, hwc, hwc->idx); } 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(hwc, hwc->idx); barrier(); /* why? */ armpmu_event_update(event, hwc, hwc->idx); 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, hwc, hwc->idx); armpmu->enable(hwc, hwc->idx); } 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 = armpmu->get_hw_events(); struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; WARN_ON(idx < 0); armpmu_stop(event, PERF_EF_UPDATE); hw_events->events[idx] = NULL; clear_bit(idx, hw_events->used_mask); 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 = armpmu->get_hw_events(); struct hw_perf_event *hwc = &event->hw; int idx; int err = 0; perf_pmu_disable(event->pmu); /* If we don't have a space for the counter then finish early. */ idx = armpmu->get_event_idx(hw_events, hwc); if (idx < 0) { err = idx; goto out; } /* * 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(hwc, idx); 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); out: perf_pmu_enable(event->pmu); return err; } static int validate_event(struct pmu_hw_events *hw_events, struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); struct hw_perf_event fake_event = event->hw; struct pmu *leader_pmu = event->group_leader->pmu; if (event->pmu != leader_pmu || event->state < PERF_EVENT_STATE_OFF) return 1; if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec) return 1; return armpmu->get_event_idx(hw_events, &fake_event) >= 0; } static int validate_group(struct perf_event *event) { struct perf_event *sibling, *leader = event->group_leader; struct pmu_hw_events fake_pmu; DECLARE_BITMAP(fake_used_mask, ARMPMU_MAX_HWEVENTS); /* * Initialise the fake PMU. We only need to populate the * used_mask for the purposes of validation. */ memset(fake_used_mask, 0, sizeof(fake_used_mask)); fake_pmu.used_mask = fake_used_mask; if (!validate_event(&fake_pmu, leader)) return -EINVAL; list_for_each_entry(sibling, &leader->sibling_list, group_entry) { if (!validate_event(&fake_pmu, sibling)) return -EINVAL; } if (!validate_event(&fake_pmu, event)) return -EINVAL; return 0; } static irqreturn_t armpmu_platform_irq(int irq, void *dev) { struct arm_pmu *armpmu = (struct arm_pmu *) dev; struct platform_device *plat_device = armpmu->plat_device; struct arm_pmu_platdata *plat = dev_get_platdata(&plat_device->dev); return plat->handle_irq(irq, dev, armpmu->handle_irq); } static void armpmu_release_hardware(struct arm_pmu *armpmu) { int i, irq, irqs; struct platform_device *pmu_device = armpmu->plat_device; irqs = min(pmu_device->num_resources, num_possible_cpus()); for (i = 0; i < irqs; ++i) { if (!cpumask_test_and_clear_cpu(i, &armpmu->active_irqs)) continue; irq = platform_get_irq(pmu_device, i); if (irq >= 0) free_irq(irq, armpmu); } release_pmu(armpmu->type); } static int armpmu_reserve_hardware(struct arm_pmu *armpmu) { struct arm_pmu_platdata *plat; irq_handler_t handle_irq; int i, err, irq, irqs; struct platform_device *pmu_device = armpmu->plat_device; if (!pmu_device) return -ENODEV; err = reserve_pmu(armpmu->type); if (err) { pr_warning("unable to reserve pmu\n"); return err; } plat = dev_get_platdata(&pmu_device->dev); if (plat && plat->handle_irq) handle_irq = armpmu_platform_irq; else handle_irq = armpmu->handle_irq; irqs = min(pmu_device->num_resources, num_possible_cpus()); if (irqs < 1) { pr_err("no irqs for PMUs defined\n"); return -ENODEV; } for (i = 0; i < irqs; ++i) { err = 0; irq = platform_get_irq(pmu_device, i); if (irq < 0) continue; /* * If we have a single PMU interrupt that we can't shift, * assume that we're running on a uniprocessor machine and * continue. Otherwise, continue without this interrupt. */ if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) { pr_warning("unable to set irq affinity (irq=%d, cpu=%u)\n", irq, i); continue; } err = request_irq(irq, handle_irq, IRQF_DISABLED | IRQF_NOBALANCING, "arm-pmu", armpmu); if (err) { pr_err("unable to request IRQ%d for ARM PMU counters\n", irq); armpmu_release_hardware(armpmu); return err; } cpumask_set_cpu(i, &armpmu->active_irqs); } return 0; } static void hw_perf_event_destroy(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); atomic_t *active_events = &armpmu->active_events; struct mutex *pmu_reserve_mutex = &armpmu->reserve_mutex; if (atomic_dec_and_mutex_lock(active_events, pmu_reserve_mutex)) { armpmu_release_hardware(armpmu); mutex_unlock(pmu_reserve_mutex); } } 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, err; 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 -EPERM; } /* * Store the event encoding into the config_base field. */ hwc->config_base |= (unsigned long)mapping; if (!hwc->sample_period) { /* * 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); } err = 0; if (event->group_leader != event) { err = validate_group(event); if (err) return -EINVAL; } return err; } static int armpmu_event_init(struct perf_event *event) { struct arm_pmu *armpmu = to_arm_pmu(event->pmu); int err = 0; atomic_t *active_events = &armpmu->active_events; if (armpmu->map_event(event) == -ENOENT) return -ENOENT; event->destroy = hw_perf_event_destroy; if (!atomic_inc_not_zero(active_events)) { mutex_lock(&armpmu->reserve_mutex); if (atomic_read(active_events) == 0) err = armpmu_reserve_hardware(armpmu); if (!err) atomic_inc(active_events); mutex_unlock(&armpmu->reserve_mutex); } if (err) return err; err = __hw_perf_event_init(event); if (err) hw_perf_event_destroy(event); return err; } static void armpmu_enable(struct pmu *pmu) { struct arm_pmu *armpmu = to_arm_pmu(pmu); struct pmu_hw_events *hw_events = armpmu->get_hw_events(); int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events); if (enabled) armpmu->start(); } static void armpmu_disable(struct pmu *pmu) { struct arm_pmu *armpmu = to_arm_pmu(pmu); armpmu->stop(); } static void __init armpmu_init(struct arm_pmu *armpmu) { atomic_set(&armpmu->active_events, 0); mutex_init(&armpmu->reserve_mutex); armpmu->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, }; } int __init armpmu_register(struct arm_pmu *armpmu, char *name, int type) { armpmu_init(armpmu); return perf_pmu_register(&armpmu->pmu, name, type); } /* Include the PMU-specific implementations. */ #include "perf_event_xscale.c" #include "perf_event_v6.c" #include "perf_event_v7.c" /* * Ensure the PMU has sane values out of reset. * This requires SMP to be available, so exists as a separate initcall. */ static int __init cpu_pmu_reset(void) { if (cpu_pmu && cpu_pmu->reset) return on_each_cpu(cpu_pmu->reset, NULL, 1); return 0; } arch_initcall(cpu_pmu_reset); /* * PMU platform driver and devicetree bindings. */ static struct of_device_id armpmu_of_device_ids[] = { {.compatible = "arm,cortex-a9-pmu"}, {.compatible = "arm,cortex-a8-pmu"}, {.compatible = "arm,arm1136-pmu"}, {.compatible = "arm,arm1176-pmu"}, {}, }; static struct platform_device_id armpmu_plat_device_ids[] = { {.name = "arm-pmu"}, {}, }; static int __devinit armpmu_device_probe(struct platform_device *pdev) { if (!cpu_pmu) return -ENODEV; cpu_pmu->plat_device = pdev; return 0; } static struct platform_driver armpmu_driver = { .driver = { .name = "arm-pmu", .of_match_table = armpmu_of_device_ids, }, .probe = armpmu_device_probe, .id_table = armpmu_plat_device_ids, }; static int __init register_pmu_driver(void) { return platform_driver_register(&armpmu_driver); } device_initcall(register_pmu_driver); static struct pmu_hw_events *armpmu_get_cpu_events(void) { return &__get_cpu_var(cpu_hw_events); } static void __init cpu_pmu_init(struct arm_pmu *armpmu) { int cpu; for_each_possible_cpu(cpu) { struct pmu_hw_events *events = &per_cpu(cpu_hw_events, cpu); events->events = per_cpu(hw_events, cpu); events->used_mask = per_cpu(used_mask, cpu); raw_spin_lock_init(&events->pmu_lock); } armpmu->get_hw_events = armpmu_get_cpu_events; armpmu->type = ARM_PMU_DEVICE_CPU; } /* * CPU PMU identification and registration. */ static int __init init_hw_perf_events(void) { unsigned long cpuid = read_cpuid_id(); unsigned long implementor = (cpuid & 0xFF000000) >> 24; unsigned long part_number = (cpuid & 0xFFF0); /* ARM Ltd CPUs. */ if (0x41 == implementor) { switch (part_number) { case 0xB360: /* ARM1136 */ case 0xB560: /* ARM1156 */ case 0xB760: /* ARM1176 */ cpu_pmu = armv6pmu_init(); break; case 0xB020: /* ARM11mpcore */ cpu_pmu = armv6mpcore_pmu_init(); break; case 0xC080: /* Cortex-A8 */ cpu_pmu = armv7_a8_pmu_init(); break; case 0xC090: /* Cortex-A9 */ cpu_pmu = armv7_a9_pmu_init(); break; case 0xC050: /* Cortex-A5 */ cpu_pmu = armv7_a5_pmu_init(); break; case 0xC0F0: /* Cortex-A15 */ cpu_pmu = armv7_a15_pmu_init(); break; } /* Intel CPUs [xscale]. */ } else if (0x69 == implementor) { part_number = (cpuid >> 13) & 0x7; switch (part_number) { case 1: cpu_pmu = xscale1pmu_init(); break; case 2: cpu_pmu = xscale2pmu_init(); break; } } if (cpu_pmu) { pr_info("enabled with %s PMU driver, %d counters available\n", cpu_pmu->name, cpu_pmu->num_events); cpu_pmu_init(cpu_pmu); armpmu_register(cpu_pmu, "cpu", PERF_TYPE_RAW); } else { pr_info("no hardware support available\n"); } return 0; } early_initcall(init_hw_perf_events); /* * Callchain handling code. */ /* * The registers we're interested in are at the end of the variable * length saved register structure. The fp points at the end of this * structure so the address of this struct is: * (struct frame_tail *)(xxx->fp)-1 * * This code has been adapted from the ARM OProfile support. */ struct frame_tail { struct frame_tail __user *fp; unsigned long sp; unsigned long lr; } __attribute__((packed)); /* * Get the return address for a single stackframe and return a pointer to the * next frame tail. */ static struct frame_tail __user * user_backtrace(struct frame_tail __user *tail, struct perf_callchain_entry *entry) { struct frame_tail buftail; /* Also check accessibility of one struct frame_tail beyond */ if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) return NULL; if (__copy_from_user_inatomic(&buftail, tail, sizeof(buftail))) return NULL; perf_callchain_store(entry, buftail.lr); /* * Frame pointers should strictly progress back up the stack * (towards higher addresses). */ if (tail + 1 >= buftail.fp) return NULL; return buftail.fp - 1; } void perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs) { struct frame_tail __user *tail; tail = (struct frame_tail __user *)regs->ARM_fp - 1; while ((entry->nr < PERF_MAX_STACK_DEPTH) && tail && !((unsigned long)tail & 0x3)) tail = user_backtrace(tail, entry); } /* * Gets called by walk_stackframe() for every stackframe. This will be called * whist unwinding the stackframe and is like a subroutine return so we use * the PC. */ static int callchain_trace(struct stackframe *fr, void *data) { struct perf_callchain_entry *entry = data; perf_callchain_store(entry, fr->pc); return 0; } void perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) { struct stackframe fr; fr.fp = regs->ARM_fp; fr.sp = regs->ARM_sp; fr.lr = regs->ARM_lr; fr.pc = regs->ARM_pc; walk_stackframe(&fr, callchain_trace, entry); }