#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 static struct platform_device *pmu_device; /* * Hardware lock to serialize accesses to PMU registers. Needed for the * read/modify/write sequences. */ static DEFINE_RAW_SPINLOCK(pmu_lock); /* * ARMv6 supports a maximum of 3 events, starting from index 1. 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 33 /* The events for a given CPU. */ struct cpu_hw_events { /* * The events that are active on the CPU for the given index. Index 0 * is reserved. */ struct perf_event *events[ARMPMU_MAX_HWEVENTS]; /* * A 1 bit for an index indicates that the counter is being used for * an event. A 0 means that the counter can be used. */ unsigned long used_mask[BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)]; /* * A 1 bit for an index indicates that the counter is actively being * used. */ unsigned long active_mask[BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)]; }; static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events); struct arm_pmu { enum arm_perf_pmu_ids id; const char *name; irqreturn_t (*handle_irq)(int irq_num, void *dev); void (*enable)(struct hw_perf_event *evt, int idx); void (*disable)(struct hw_perf_event *evt, int idx); int (*get_event_idx)(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc); u32 (*read_counter)(int idx); void (*write_counter)(int idx, u32 val); void (*start)(void); void (*stop)(void); void (*reset)(void *); const unsigned (*cache_map)[PERF_COUNT_HW_CACHE_MAX] [PERF_COUNT_HW_CACHE_OP_MAX] [PERF_COUNT_HW_CACHE_RESULT_MAX]; const unsigned (*event_map)[PERF_COUNT_HW_MAX]; u32 raw_event_mask; int num_events; u64 max_period; }; /* Set at runtime when we know what CPU type we are. */ static const struct arm_pmu *armpmu; enum arm_perf_pmu_ids armpmu_get_pmu_id(void) { int id = -ENODEV; if (armpmu != NULL) id = armpmu->id; return id; } EXPORT_SYMBOL_GPL(armpmu_get_pmu_id); int armpmu_get_max_events(void) { int max_events = 0; if (armpmu != NULL) max_events = armpmu->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(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)(*armpmu->cache_map)[cache_type][cache_op][cache_result]; if (ret == CACHE_OP_UNSUPPORTED) return -ENOENT; return ret; } static int armpmu_map_event(u64 config) { int mapping = (*armpmu->event_map)[config]; return mapping == HW_OP_UNSUPPORTED ? -EOPNOTSUPP : mapping; } static int armpmu_map_raw_event(u64 config) { return (int)(config & armpmu->raw_event_mask); } static int armpmu_event_set_period(struct perf_event *event, struct hw_perf_event *hwc, int idx) { 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; } static u64 armpmu_event_update(struct perf_event *event, struct hw_perf_event *hwc, int idx, int overflow) { 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; new_raw_count &= armpmu->max_period; prev_raw_count &= armpmu->max_period; if (overflow) delta = armpmu->max_period - prev_raw_count + new_raw_count + 1; else delta = new_raw_count - prev_raw_count; 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, 0); } static void armpmu_stop(struct perf_event *event, int flags) { struct hw_perf_event *hwc = &event->hw; if (!armpmu) return; /* * 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, 0); hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE; } } static void armpmu_start(struct perf_event *event, int flags) { struct hw_perf_event *hwc = &event->hw; if (!armpmu) return; /* * 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 cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; WARN_ON(idx < 0); clear_bit(idx, cpuc->active_mask); armpmu_stop(event, PERF_EF_UPDATE); cpuc->events[idx] = NULL; clear_bit(idx, cpuc->used_mask); perf_event_update_userpage(event); } static int armpmu_add(struct perf_event *event, int flags) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_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(cpuc, 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); cpuc->events[idx] = event; set_bit(idx, cpuc->active_mask); 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 struct pmu pmu; static int validate_event(struct cpu_hw_events *cpuc, struct perf_event *event) { struct hw_perf_event fake_event = event->hw; if (event->pmu != &pmu || event->state <= PERF_EVENT_STATE_OFF) return 1; return armpmu->get_event_idx(cpuc, &fake_event) >= 0; } static int validate_group(struct perf_event *event) { struct perf_event *sibling, *leader = event->group_leader; struct cpu_hw_events fake_pmu; memset(&fake_pmu, 0, sizeof(fake_pmu)); if (!validate_event(&fake_pmu, leader)) return -ENOSPC; list_for_each_entry(sibling, &leader->sibling_list, group_entry) { if (!validate_event(&fake_pmu, sibling)) return -ENOSPC; } if (!validate_event(&fake_pmu, event)) return -ENOSPC; return 0; } static irqreturn_t armpmu_platform_irq(int irq, void *dev) { struct arm_pmu_platdata *plat = dev_get_platdata(&pmu_device->dev); return plat->handle_irq(irq, dev, armpmu->handle_irq); } static int armpmu_reserve_hardware(void) { struct arm_pmu_platdata *plat; irq_handler_t handle_irq; int i, err = -ENODEV, irq; pmu_device = reserve_pmu(ARM_PMU_DEVICE_CPU); if (IS_ERR(pmu_device)) { pr_warning("unable to reserve pmu\n"); return PTR_ERR(pmu_device); } init_pmu(ARM_PMU_DEVICE_CPU); plat = dev_get_platdata(&pmu_device->dev); if (plat && plat->handle_irq) handle_irq = armpmu_platform_irq; else handle_irq = armpmu->handle_irq; if (pmu_device->num_resources < 1) { pr_err("no irqs for PMUs defined\n"); return -ENODEV; } for (i = 0; i < pmu_device->num_resources; ++i) { irq = platform_get_irq(pmu_device, i); if (irq < 0) continue; err = request_irq(irq, handle_irq, IRQF_DISABLED | IRQF_NOBALANCING, "armpmu", NULL); if (err) { pr_warning("unable to request IRQ%d for ARM perf " "counters\n", irq); break; } } if (err) { for (i = i - 1; i >= 0; --i) { irq = platform_get_irq(pmu_device, i); if (irq >= 0) free_irq(irq, NULL); } release_pmu(ARM_PMU_DEVICE_CPU); pmu_device = NULL; } return err; } static void armpmu_release_hardware(void) { int i, irq; for (i = pmu_device->num_resources - 1; i >= 0; --i) { irq = platform_get_irq(pmu_device, i); if (irq >= 0) free_irq(irq, NULL); } armpmu->stop(); release_pmu(ARM_PMU_DEVICE_CPU); pmu_device = NULL; } static atomic_t active_events = ATOMIC_INIT(0); static DEFINE_MUTEX(pmu_reserve_mutex); static void hw_perf_event_destroy(struct perf_event *event) { if (atomic_dec_and_mutex_lock(&active_events, &pmu_reserve_mutex)) { armpmu_release_hardware(); mutex_unlock(&pmu_reserve_mutex); } } static int __hw_perf_event_init(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; int mapping, err; /* Decode the generic type into an ARM event identifier. */ if (PERF_TYPE_HARDWARE == event->attr.type) { mapping = armpmu_map_event(event->attr.config); } else if (PERF_TYPE_HW_CACHE == event->attr.type) { mapping = armpmu_map_cache_event(event->attr.config); } else if (PERF_TYPE_RAW == event->attr.type) { mapping = armpmu_map_raw_event(event->attr.config); } else { pr_debug("event type %x not supported\n", event->attr.type); return -EOPNOTSUPP; } if (mapping < 0) { pr_debug("event %x:%llx not supported\n", event->attr.type, event->attr.config); return mapping; } /* * Check whether we need to exclude the counter from certain modes. * The ARM performance counters are on all of the time so if someone * has asked us for some excludes then we have to fail. */ if (event->attr.exclude_kernel || event->attr.exclude_user || event->attr.exclude_hv || event->attr.exclude_idle) { pr_debug("ARM performance counters do not support " "mode exclusion\n"); return -EPERM; } /* * 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; /* * Store the event encoding into the config_base field. config and * event_base are unused as the only 2 things we need to know are * the event mapping and the counter to use. The counter to use is * also the indx and the config_base is the event type. */ hwc->config_base = (unsigned long)mapping; hwc->config = 0; hwc->event_base = 0; if (!hwc->sample_period) { hwc->sample_period = armpmu->max_period; 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) { int err = 0; switch (event->attr.type) { case PERF_TYPE_RAW: case PERF_TYPE_HARDWARE: case PERF_TYPE_HW_CACHE: break; default: return -ENOENT; } if (!armpmu) return -ENODEV; event->destroy = hw_perf_event_destroy; if (!atomic_inc_not_zero(&active_events)) { mutex_lock(&pmu_reserve_mutex); if (atomic_read(&active_events) == 0) { err = armpmu_reserve_hardware(); } if (!err) atomic_inc(&active_events); mutex_unlock(&pmu_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) { /* Enable all of the perf events on hardware. */ int idx, enabled = 0; struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); if (!armpmu) return; for (idx = 0; idx <= armpmu->num_events; ++idx) { struct perf_event *event = cpuc->events[idx]; if (!event) continue; armpmu->enable(&event->hw, idx); enabled = 1; } if (enabled) armpmu->start(); } static void armpmu_disable(struct pmu *pmu) { if (armpmu) armpmu->stop(); } static struct pmu 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, }; /* 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 armpmu_reset(void) { if (armpmu && armpmu->reset) return on_each_cpu(armpmu->reset, NULL, 1); return 0; } arch_initcall(armpmu_reset); 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 */ armpmu = armv6pmu_init(); break; case 0xB020: /* ARM11mpcore */ armpmu = armv6mpcore_pmu_init(); break; case 0xC080: /* Cortex-A8 */ armpmu = armv7_a8_pmu_init(); break; case 0xC090: /* Cortex-A9 */ armpmu = armv7_a9_pmu_init(); break; case 0xC050: /* Cortex-A5 */ armpmu = armv7_a5_pmu_init(); break; case 0xC0F0: /* Cortex-A15 */ armpmu = armv7_a15_pmu_init(); break; } /* Intel CPUs [xscale]. */ } else if (0x69 == implementor) { part_number = (cpuid >> 13) & 0x7; switch (part_number) { case 1: armpmu = xscale1pmu_init(); break; case 2: armpmu = xscale2pmu_init(); break; } } if (armpmu) { pr_info("enabled with %s PMU driver, %d counters available\n", armpmu->name, armpmu->num_events); } else { pr_info("no hardware support available\n"); } perf_pmu_register(&pmu, "cpu", PERF_TYPE_RAW); 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); }