/* * Performance counter x86 architecture code * * Copyright (C) 2008 Thomas Gleixner * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar * Copyright (C) 2009 Jaswinder Singh Rajput * Copyright (C) 2009 Advanced Micro Devices, Inc., Robert Richter * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra * * For licencing details see kernel-base/COPYING */ #include #include #include #include #include #include #include #include #include #include #include #include static u64 perf_counter_mask __read_mostly; struct cpu_hw_counters { struct perf_counter *counters[X86_PMC_IDX_MAX]; unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; unsigned long interrupts; int enabled; }; /* * struct x86_pmu - generic x86 pmu */ struct x86_pmu { const char *name; int version; int (*handle_irq)(struct pt_regs *, int); void (*disable_all)(void); void (*enable_all)(void); void (*enable)(struct hw_perf_counter *, int); void (*disable)(struct hw_perf_counter *, int); unsigned eventsel; unsigned perfctr; u64 (*event_map)(int); u64 (*raw_event)(u64); int max_events; int num_counters; int num_counters_fixed; int counter_bits; u64 counter_mask; u64 max_period; u64 intel_ctrl; }; static struct x86_pmu x86_pmu __read_mostly; static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters) = { .enabled = 1, }; /* * Intel PerfMon v3. Used on Core2 and later. */ static const u64 intel_perfmon_event_map[] = { [PERF_COUNT_CPU_CYCLES] = 0x003c, [PERF_COUNT_INSTRUCTIONS] = 0x00c0, [PERF_COUNT_CACHE_REFERENCES] = 0x4f2e, [PERF_COUNT_CACHE_MISSES] = 0x412e, [PERF_COUNT_BRANCH_INSTRUCTIONS] = 0x00c4, [PERF_COUNT_BRANCH_MISSES] = 0x00c5, [PERF_COUNT_BUS_CYCLES] = 0x013c, }; static u64 intel_pmu_event_map(int event) { return intel_perfmon_event_map[event]; } static u64 intel_pmu_raw_event(u64 event) { #define CORE_EVNTSEL_EVENT_MASK 0x000000FFULL #define CORE_EVNTSEL_UNIT_MASK 0x0000FF00ULL #define CORE_EVNTSEL_COUNTER_MASK 0xFF000000ULL #define CORE_EVNTSEL_MASK \ (CORE_EVNTSEL_EVENT_MASK | \ CORE_EVNTSEL_UNIT_MASK | \ CORE_EVNTSEL_COUNTER_MASK) return event & CORE_EVNTSEL_MASK; } /* * AMD Performance Monitor K7 and later. */ static const u64 amd_perfmon_event_map[] = { [PERF_COUNT_CPU_CYCLES] = 0x0076, [PERF_COUNT_INSTRUCTIONS] = 0x00c0, [PERF_COUNT_CACHE_REFERENCES] = 0x0080, [PERF_COUNT_CACHE_MISSES] = 0x0081, [PERF_COUNT_BRANCH_INSTRUCTIONS] = 0x00c4, [PERF_COUNT_BRANCH_MISSES] = 0x00c5, }; static u64 amd_pmu_event_map(int event) { return amd_perfmon_event_map[event]; } static u64 amd_pmu_raw_event(u64 event) { #define K7_EVNTSEL_EVENT_MASK 0x7000000FFULL #define K7_EVNTSEL_UNIT_MASK 0x00000FF00ULL #define K7_EVNTSEL_COUNTER_MASK 0x0FF000000ULL #define K7_EVNTSEL_MASK \ (K7_EVNTSEL_EVENT_MASK | \ K7_EVNTSEL_UNIT_MASK | \ K7_EVNTSEL_COUNTER_MASK) return event & K7_EVNTSEL_MASK; } /* * Propagate counter elapsed time into the generic counter. * Can only be executed on the CPU where the counter is active. * Returns the delta events processed. */ static u64 x86_perf_counter_update(struct perf_counter *counter, struct hw_perf_counter *hwc, int idx) { int shift = 64 - x86_pmu.counter_bits; u64 prev_raw_count, new_raw_count; s64 delta; /* * Careful: an NMI might modify the previous counter value. * * Our tactic to handle this is to first atomically read and * exchange a new raw count - then add that new-prev delta * count to the generic counter atomically: */ again: prev_raw_count = atomic64_read(&hwc->prev_count); rdmsrl(hwc->counter_base + idx, new_raw_count); if (atomic64_cmpxchg(&hwc->prev_count, prev_raw_count, new_raw_count) != prev_raw_count) goto again; /* * Now we have the new raw value and have updated the prev * timestamp already. We can now calculate the elapsed delta * (counter-)time and add that to the generic counter. * * Careful, not all hw sign-extends above the physical width * of the count. */ delta = (new_raw_count << shift) - (prev_raw_count << shift); delta >>= shift; atomic64_add(delta, &counter->count); atomic64_sub(delta, &hwc->period_left); return new_raw_count; } static atomic_t active_counters; static DEFINE_MUTEX(pmc_reserve_mutex); static bool reserve_pmc_hardware(void) { int i; if (nmi_watchdog == NMI_LOCAL_APIC) disable_lapic_nmi_watchdog(); for (i = 0; i < x86_pmu.num_counters; i++) { if (!reserve_perfctr_nmi(x86_pmu.perfctr + i)) goto perfctr_fail; } for (i = 0; i < x86_pmu.num_counters; i++) { if (!reserve_evntsel_nmi(x86_pmu.eventsel + i)) goto eventsel_fail; } return true; eventsel_fail: for (i--; i >= 0; i--) release_evntsel_nmi(x86_pmu.eventsel + i); i = x86_pmu.num_counters; perfctr_fail: for (i--; i >= 0; i--) release_perfctr_nmi(x86_pmu.perfctr + i); if (nmi_watchdog == NMI_LOCAL_APIC) enable_lapic_nmi_watchdog(); return false; } static void release_pmc_hardware(void) { int i; for (i = 0; i < x86_pmu.num_counters; i++) { release_perfctr_nmi(x86_pmu.perfctr + i); release_evntsel_nmi(x86_pmu.eventsel + i); } if (nmi_watchdog == NMI_LOCAL_APIC) enable_lapic_nmi_watchdog(); } static void hw_perf_counter_destroy(struct perf_counter *counter) { if (atomic_dec_and_mutex_lock(&active_counters, &pmc_reserve_mutex)) { release_pmc_hardware(); mutex_unlock(&pmc_reserve_mutex); } } static inline int x86_pmu_initialized(void) { return x86_pmu.handle_irq != NULL; } /* * Setup the hardware configuration for a given hw_event_type */ static int __hw_perf_counter_init(struct perf_counter *counter) { struct perf_counter_hw_event *hw_event = &counter->hw_event; struct hw_perf_counter *hwc = &counter->hw; int err; if (!x86_pmu_initialized()) return -ENODEV; err = 0; if (!atomic_inc_not_zero(&active_counters)) { mutex_lock(&pmc_reserve_mutex); if (atomic_read(&active_counters) == 0 && !reserve_pmc_hardware()) err = -EBUSY; else atomic_inc(&active_counters); mutex_unlock(&pmc_reserve_mutex); } if (err) return err; /* * Generate PMC IRQs: * (keep 'enabled' bit clear for now) */ hwc->config = ARCH_PERFMON_EVENTSEL_INT; /* * Count user and OS events unless requested not to. */ if (!hw_event->exclude_user) hwc->config |= ARCH_PERFMON_EVENTSEL_USR; if (!hw_event->exclude_kernel) hwc->config |= ARCH_PERFMON_EVENTSEL_OS; /* * If privileged enough, allow NMI events: */ hwc->nmi = 0; if (hw_event->nmi) { if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN)) return -EACCES; hwc->nmi = 1; } if (!hwc->irq_period) hwc->irq_period = x86_pmu.max_period; atomic64_set(&hwc->period_left, min(x86_pmu.max_period, hwc->irq_period)); /* * Raw event type provide the config in the event structure */ if (perf_event_raw(hw_event)) { hwc->config |= x86_pmu.raw_event(perf_event_config(hw_event)); } else { if (perf_event_id(hw_event) >= x86_pmu.max_events) return -EINVAL; /* * The generic map: */ hwc->config |= x86_pmu.event_map(perf_event_id(hw_event)); } counter->destroy = hw_perf_counter_destroy; return 0; } static void intel_pmu_disable_all(void) { wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0); } static void amd_pmu_disable_all(void) { struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); int idx; if (!cpuc->enabled) return; cpuc->enabled = 0; /* * ensure we write the disable before we start disabling the * counters proper, so that amd_pmu_enable_counter() does the * right thing. */ barrier(); for (idx = 0; idx < x86_pmu.num_counters; idx++) { u64 val; if (!test_bit(idx, cpuc->active_mask)) continue; rdmsrl(MSR_K7_EVNTSEL0 + idx, val); if (!(val & ARCH_PERFMON_EVENTSEL0_ENABLE)) continue; val &= ~ARCH_PERFMON_EVENTSEL0_ENABLE; wrmsrl(MSR_K7_EVNTSEL0 + idx, val); } } void hw_perf_disable(void) { if (!x86_pmu_initialized()) return; return x86_pmu.disable_all(); } static void intel_pmu_enable_all(void) { wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl); } static void amd_pmu_enable_all(void) { struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); int idx; if (cpuc->enabled) return; cpuc->enabled = 1; barrier(); for (idx = 0; idx < x86_pmu.num_counters; idx++) { u64 val; if (!test_bit(idx, cpuc->active_mask)) continue; rdmsrl(MSR_K7_EVNTSEL0 + idx, val); if (val & ARCH_PERFMON_EVENTSEL0_ENABLE) continue; val |= ARCH_PERFMON_EVENTSEL0_ENABLE; wrmsrl(MSR_K7_EVNTSEL0 + idx, val); } } void hw_perf_enable(void) { if (!x86_pmu_initialized()) return; x86_pmu.enable_all(); } static inline u64 intel_pmu_get_status(void) { u64 status; rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status); return status; } static inline void intel_pmu_ack_status(u64 ack) { wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack); } static inline void x86_pmu_enable_counter(struct hw_perf_counter *hwc, int idx) { int err; err = checking_wrmsrl(hwc->config_base + idx, hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE); } static inline void x86_pmu_disable_counter(struct hw_perf_counter *hwc, int idx) { int err; err = checking_wrmsrl(hwc->config_base + idx, hwc->config); } static inline void intel_pmu_disable_fixed(struct hw_perf_counter *hwc, int __idx) { int idx = __idx - X86_PMC_IDX_FIXED; u64 ctrl_val, mask; int err; mask = 0xfULL << (idx * 4); rdmsrl(hwc->config_base, ctrl_val); ctrl_val &= ~mask; err = checking_wrmsrl(hwc->config_base, ctrl_val); } static inline void intel_pmu_disable_counter(struct hw_perf_counter *hwc, int idx) { if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) { intel_pmu_disable_fixed(hwc, idx); return; } x86_pmu_disable_counter(hwc, idx); } static inline void amd_pmu_disable_counter(struct hw_perf_counter *hwc, int idx) { x86_pmu_disable_counter(hwc, idx); } static DEFINE_PER_CPU(u64, prev_left[X86_PMC_IDX_MAX]); /* * Set the next IRQ period, based on the hwc->period_left value. * To be called with the counter disabled in hw: */ static void x86_perf_counter_set_period(struct perf_counter *counter, struct hw_perf_counter *hwc, int idx) { s64 left = atomic64_read(&hwc->period_left); s64 period = min(x86_pmu.max_period, hwc->irq_period); int err; /* * If we are way outside a reasoable range then just skip forward: */ if (unlikely(left <= -period)) { left = period; atomic64_set(&hwc->period_left, left); } if (unlikely(left <= 0)) { left += period; atomic64_set(&hwc->period_left, left); } /* * Quirk: certain CPUs dont like it if just 1 event is left: */ if (unlikely(left < 2)) left = 2; per_cpu(prev_left[idx], smp_processor_id()) = left; /* * The hw counter starts counting from this counter offset, * mark it to be able to extra future deltas: */ atomic64_set(&hwc->prev_count, (u64)-left); err = checking_wrmsrl(hwc->counter_base + idx, (u64)(-left) & x86_pmu.counter_mask); } static inline void intel_pmu_enable_fixed(struct hw_perf_counter *hwc, int __idx) { int idx = __idx - X86_PMC_IDX_FIXED; u64 ctrl_val, bits, mask; int err; /* * Enable IRQ generation (0x8), * and enable ring-3 counting (0x2) and ring-0 counting (0x1) * if requested: */ bits = 0x8ULL; if (hwc->config & ARCH_PERFMON_EVENTSEL_USR) bits |= 0x2; if (hwc->config & ARCH_PERFMON_EVENTSEL_OS) bits |= 0x1; bits <<= (idx * 4); mask = 0xfULL << (idx * 4); rdmsrl(hwc->config_base, ctrl_val); ctrl_val &= ~mask; ctrl_val |= bits; err = checking_wrmsrl(hwc->config_base, ctrl_val); } static void intel_pmu_enable_counter(struct hw_perf_counter *hwc, int idx) { if (unlikely(hwc->config_base == MSR_ARCH_PERFMON_FIXED_CTR_CTRL)) { intel_pmu_enable_fixed(hwc, idx); return; } x86_pmu_enable_counter(hwc, idx); } static void amd_pmu_enable_counter(struct hw_perf_counter *hwc, int idx) { struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); if (cpuc->enabled) x86_pmu_enable_counter(hwc, idx); else x86_pmu_disable_counter(hwc, idx); } static int fixed_mode_idx(struct perf_counter *counter, struct hw_perf_counter *hwc) { unsigned int event; if (!x86_pmu.num_counters_fixed) return -1; if (unlikely(hwc->nmi)) return -1; event = hwc->config & ARCH_PERFMON_EVENT_MASK; if (unlikely(event == x86_pmu.event_map(PERF_COUNT_INSTRUCTIONS))) return X86_PMC_IDX_FIXED_INSTRUCTIONS; if (unlikely(event == x86_pmu.event_map(PERF_COUNT_CPU_CYCLES))) return X86_PMC_IDX_FIXED_CPU_CYCLES; if (unlikely(event == x86_pmu.event_map(PERF_COUNT_BUS_CYCLES))) return X86_PMC_IDX_FIXED_BUS_CYCLES; return -1; } /* * Find a PMC slot for the freshly enabled / scheduled in counter: */ static int x86_pmu_enable(struct perf_counter *counter) { struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); struct hw_perf_counter *hwc = &counter->hw; int idx; idx = fixed_mode_idx(counter, hwc); if (idx >= 0) { /* * Try to get the fixed counter, if that is already taken * then try to get a generic counter: */ if (test_and_set_bit(idx, cpuc->used_mask)) goto try_generic; hwc->config_base = MSR_ARCH_PERFMON_FIXED_CTR_CTRL; /* * We set it so that counter_base + idx in wrmsr/rdmsr maps to * MSR_ARCH_PERFMON_FIXED_CTR0 ... CTR2: */ hwc->counter_base = MSR_ARCH_PERFMON_FIXED_CTR0 - X86_PMC_IDX_FIXED; hwc->idx = idx; } else { idx = hwc->idx; /* Try to get the previous generic counter again */ if (test_and_set_bit(idx, cpuc->used_mask)) { try_generic: idx = find_first_zero_bit(cpuc->used_mask, x86_pmu.num_counters); if (idx == x86_pmu.num_counters) return -EAGAIN; set_bit(idx, cpuc->used_mask); hwc->idx = idx; } hwc->config_base = x86_pmu.eventsel; hwc->counter_base = x86_pmu.perfctr; } perf_counters_lapic_init(hwc->nmi); x86_pmu.disable(hwc, idx); cpuc->counters[idx] = counter; set_bit(idx, cpuc->active_mask); x86_perf_counter_set_period(counter, hwc, idx); x86_pmu.enable(hwc, idx); return 0; } void perf_counter_print_debug(void) { u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed; struct cpu_hw_counters *cpuc; unsigned long flags; int cpu, idx; if (!x86_pmu.num_counters) return; local_irq_save(flags); cpu = smp_processor_id(); cpuc = &per_cpu(cpu_hw_counters, cpu); if (x86_pmu.version >= 2) { rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl); rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status); rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow); rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, fixed); pr_info("\n"); pr_info("CPU#%d: ctrl: %016llx\n", cpu, ctrl); pr_info("CPU#%d: status: %016llx\n", cpu, status); pr_info("CPU#%d: overflow: %016llx\n", cpu, overflow); pr_info("CPU#%d: fixed: %016llx\n", cpu, fixed); } pr_info("CPU#%d: used: %016llx\n", cpu, *(u64 *)cpuc->used_mask); for (idx = 0; idx < x86_pmu.num_counters; idx++) { rdmsrl(x86_pmu.eventsel + idx, pmc_ctrl); rdmsrl(x86_pmu.perfctr + idx, pmc_count); prev_left = per_cpu(prev_left[idx], cpu); pr_info("CPU#%d: gen-PMC%d ctrl: %016llx\n", cpu, idx, pmc_ctrl); pr_info("CPU#%d: gen-PMC%d count: %016llx\n", cpu, idx, pmc_count); pr_info("CPU#%d: gen-PMC%d left: %016llx\n", cpu, idx, prev_left); } for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++) { rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count); pr_info("CPU#%d: fixed-PMC%d count: %016llx\n", cpu, idx, pmc_count); } local_irq_restore(flags); } static void x86_pmu_disable(struct perf_counter *counter) { struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); struct hw_perf_counter *hwc = &counter->hw; int idx = hwc->idx; /* * Must be done before we disable, otherwise the nmi handler * could reenable again: */ clear_bit(idx, cpuc->active_mask); x86_pmu.disable(hwc, idx); /* * Make sure the cleared pointer becomes visible before we * (potentially) free the counter: */ barrier(); /* * Drain the remaining delta count out of a counter * that we are disabling: */ x86_perf_counter_update(counter, hwc, idx); cpuc->counters[idx] = NULL; clear_bit(idx, cpuc->used_mask); } /* * Save and restart an expired counter. Called by NMI contexts, * so it has to be careful about preempting normal counter ops: */ static void intel_pmu_save_and_restart(struct perf_counter *counter) { struct hw_perf_counter *hwc = &counter->hw; int idx = hwc->idx; x86_perf_counter_update(counter, hwc, idx); x86_perf_counter_set_period(counter, hwc, idx); if (counter->state == PERF_COUNTER_STATE_ACTIVE) intel_pmu_enable_counter(hwc, idx); } /* * Maximum interrupt frequency of 100KHz per CPU */ #define PERFMON_MAX_INTERRUPTS (100000/HZ) /* * This handler is triggered by the local APIC, so the APIC IRQ handling * rules apply: */ static int intel_pmu_handle_irq(struct pt_regs *regs, int nmi) { struct cpu_hw_counters *cpuc; struct cpu_hw_counters; int bit, cpu, loops; u64 ack, status; cpu = smp_processor_id(); cpuc = &per_cpu(cpu_hw_counters, cpu); perf_disable(); status = intel_pmu_get_status(); if (!status) { perf_enable(); return 0; } loops = 0; again: if (++loops > 100) { WARN_ONCE(1, "perfcounters: irq loop stuck!\n"); return 1; } inc_irq_stat(apic_perf_irqs); ack = status; for_each_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) { struct perf_counter *counter = cpuc->counters[bit]; clear_bit(bit, (unsigned long *) &status); if (!test_bit(bit, cpuc->active_mask)) continue; intel_pmu_save_and_restart(counter); if (perf_counter_overflow(counter, nmi, regs, 0)) intel_pmu_disable_counter(&counter->hw, bit); } intel_pmu_ack_status(ack); /* * Repeat if there is more work to be done: */ status = intel_pmu_get_status(); if (status) goto again; if (++cpuc->interrupts != PERFMON_MAX_INTERRUPTS) perf_enable(); return 1; } static int amd_pmu_handle_irq(struct pt_regs *regs, int nmi) { int cpu, idx, throttle = 0, handled = 0; struct cpu_hw_counters *cpuc; struct perf_counter *counter; struct hw_perf_counter *hwc; u64 val; cpu = smp_processor_id(); cpuc = &per_cpu(cpu_hw_counters, cpu); if (++cpuc->interrupts == PERFMON_MAX_INTERRUPTS) { throttle = 1; __perf_disable(); cpuc->enabled = 0; barrier(); } for (idx = 0; idx < x86_pmu.num_counters; idx++) { int disable = 0; if (!test_bit(idx, cpuc->active_mask)) continue; counter = cpuc->counters[idx]; hwc = &counter->hw; if (counter->hw_event.nmi != nmi) goto next; val = x86_perf_counter_update(counter, hwc, idx); if (val & (1ULL << (x86_pmu.counter_bits - 1))) goto next; /* counter overflow */ x86_perf_counter_set_period(counter, hwc, idx); handled = 1; inc_irq_stat(apic_perf_irqs); disable = perf_counter_overflow(counter, nmi, regs, 0); next: if (disable || throttle) amd_pmu_disable_counter(hwc, idx); } return handled; } void perf_counter_unthrottle(void) { struct cpu_hw_counters *cpuc; if (!x86_pmu_initialized()) return; cpuc = &__get_cpu_var(cpu_hw_counters); if (cpuc->interrupts >= PERFMON_MAX_INTERRUPTS) { /* * Clear them before re-enabling irqs/NMIs again: */ cpuc->interrupts = 0; perf_enable(); } else { cpuc->interrupts = 0; } } void smp_perf_counter_interrupt(struct pt_regs *regs) { irq_enter(); apic_write(APIC_LVTPC, LOCAL_PERF_VECTOR); ack_APIC_irq(); x86_pmu.handle_irq(regs, 0); irq_exit(); } void smp_perf_pending_interrupt(struct pt_regs *regs) { irq_enter(); ack_APIC_irq(); inc_irq_stat(apic_pending_irqs); perf_counter_do_pending(); irq_exit(); } void set_perf_counter_pending(void) { apic->send_IPI_self(LOCAL_PENDING_VECTOR); } void perf_counters_lapic_init(int nmi) { u32 apic_val; if (!x86_pmu_initialized()) return; /* * Enable the performance counter vector in the APIC LVT: */ apic_val = apic_read(APIC_LVTERR); apic_write(APIC_LVTERR, apic_val | APIC_LVT_MASKED); if (nmi) apic_write(APIC_LVTPC, APIC_DM_NMI); else apic_write(APIC_LVTPC, LOCAL_PERF_VECTOR); apic_write(APIC_LVTERR, apic_val); } static int __kprobes perf_counter_nmi_handler(struct notifier_block *self, unsigned long cmd, void *__args) { struct die_args *args = __args; struct pt_regs *regs; if (!atomic_read(&active_counters)) return NOTIFY_DONE; switch (cmd) { case DIE_NMI: case DIE_NMI_IPI: break; default: return NOTIFY_DONE; } regs = args->regs; apic_write(APIC_LVTPC, APIC_DM_NMI); /* * Can't rely on the handled return value to say it was our NMI, two * counters could trigger 'simultaneously' raising two back-to-back NMIs. * * If the first NMI handles both, the latter will be empty and daze * the CPU. */ x86_pmu.handle_irq(regs, 1); return NOTIFY_STOP; } static __read_mostly struct notifier_block perf_counter_nmi_notifier = { .notifier_call = perf_counter_nmi_handler, .next = NULL, .priority = 1 }; static struct x86_pmu intel_pmu = { .name = "Intel", .handle_irq = intel_pmu_handle_irq, .disable_all = intel_pmu_disable_all, .enable_all = intel_pmu_enable_all, .enable = intel_pmu_enable_counter, .disable = intel_pmu_disable_counter, .eventsel = MSR_ARCH_PERFMON_EVENTSEL0, .perfctr = MSR_ARCH_PERFMON_PERFCTR0, .event_map = intel_pmu_event_map, .raw_event = intel_pmu_raw_event, .max_events = ARRAY_SIZE(intel_perfmon_event_map), /* * Intel PMCs cannot be accessed sanely above 32 bit width, * so we install an artificial 1<<31 period regardless of * the generic counter period: */ .max_period = (1ULL << 31) - 1, }; static struct x86_pmu amd_pmu = { .name = "AMD", .handle_irq = amd_pmu_handle_irq, .disable_all = amd_pmu_disable_all, .enable_all = amd_pmu_enable_all, .enable = amd_pmu_enable_counter, .disable = amd_pmu_disable_counter, .eventsel = MSR_K7_EVNTSEL0, .perfctr = MSR_K7_PERFCTR0, .event_map = amd_pmu_event_map, .raw_event = amd_pmu_raw_event, .max_events = ARRAY_SIZE(amd_perfmon_event_map), .num_counters = 4, .counter_bits = 48, .counter_mask = (1ULL << 48) - 1, /* use highest bit to detect overflow */ .max_period = (1ULL << 47) - 1, }; static int intel_pmu_init(void) { union cpuid10_edx edx; union cpuid10_eax eax; unsigned int unused; unsigned int ebx; int version; if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) return -ENODEV; /* * Check whether the Architectural PerfMon supports * Branch Misses Retired Event or not. */ cpuid(10, &eax.full, &ebx, &unused, &edx.full); if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED) return -ENODEV; version = eax.split.version_id; if (version < 2) return -ENODEV; x86_pmu = intel_pmu; x86_pmu.version = version; x86_pmu.num_counters = eax.split.num_counters; /* * Quirk: v2 perfmon does not report fixed-purpose counters, so * assume at least 3 counters: */ x86_pmu.num_counters_fixed = max((int)edx.split.num_counters_fixed, 3); x86_pmu.counter_bits = eax.split.bit_width; x86_pmu.counter_mask = (1ULL << eax.split.bit_width) - 1; rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl); return 0; } static int amd_pmu_init(void) { x86_pmu = amd_pmu; return 0; } void __init init_hw_perf_counters(void) { int err; switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: err = intel_pmu_init(); break; case X86_VENDOR_AMD: err = amd_pmu_init(); break; default: return; } if (err != 0) return; pr_info("%s Performance Monitoring support detected.\n", x86_pmu.name); pr_info("... version: %d\n", x86_pmu.version); pr_info("... bit width: %d\n", x86_pmu.counter_bits); pr_info("... num counters: %d\n", x86_pmu.num_counters); if (x86_pmu.num_counters > X86_PMC_MAX_GENERIC) { x86_pmu.num_counters = X86_PMC_MAX_GENERIC; WARN(1, KERN_ERR "hw perf counters %d > max(%d), clipping!", x86_pmu.num_counters, X86_PMC_MAX_GENERIC); } perf_counter_mask = (1 << x86_pmu.num_counters) - 1; perf_max_counters = x86_pmu.num_counters; pr_info("... value mask: %016Lx\n", x86_pmu.counter_mask); pr_info("... max period: %016Lx\n", x86_pmu.max_period); if (x86_pmu.num_counters_fixed > X86_PMC_MAX_FIXED) { x86_pmu.num_counters_fixed = X86_PMC_MAX_FIXED; WARN(1, KERN_ERR "hw perf counters fixed %d > max(%d), clipping!", x86_pmu.num_counters_fixed, X86_PMC_MAX_FIXED); } pr_info("... fixed counters: %d\n", x86_pmu.num_counters_fixed); perf_counter_mask |= ((1LL << x86_pmu.num_counters_fixed)-1) << X86_PMC_IDX_FIXED; pr_info("... counter mask: %016Lx\n", perf_counter_mask); perf_counters_lapic_init(0); register_die_notifier(&perf_counter_nmi_notifier); } static inline void x86_pmu_read(struct perf_counter *counter) { x86_perf_counter_update(counter, &counter->hw, counter->hw.idx); } static const struct pmu pmu = { .enable = x86_pmu_enable, .disable = x86_pmu_disable, .read = x86_pmu_read, }; const struct pmu *hw_perf_counter_init(struct perf_counter *counter) { int err; err = __hw_perf_counter_init(counter); if (err) return ERR_PTR(err); return &pmu; } /* * callchain support */ static inline void callchain_store(struct perf_callchain_entry *entry, unsigned long ip) { if (entry->nr < MAX_STACK_DEPTH) entry->ip[entry->nr++] = ip; } static DEFINE_PER_CPU(struct perf_callchain_entry, irq_entry); static DEFINE_PER_CPU(struct perf_callchain_entry, nmi_entry); static void backtrace_warning_symbol(void *data, char *msg, unsigned long symbol) { /* Ignore warnings */ } static void backtrace_warning(void *data, char *msg) { /* Ignore warnings */ } static int backtrace_stack(void *data, char *name) { /* Don't bother with IRQ stacks for now */ return -1; } static void backtrace_address(void *data, unsigned long addr, int reliable) { struct perf_callchain_entry *entry = data; if (reliable) callchain_store(entry, addr); } static const struct stacktrace_ops backtrace_ops = { .warning = backtrace_warning, .warning_symbol = backtrace_warning_symbol, .stack = backtrace_stack, .address = backtrace_address, }; static void perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry) { unsigned long bp; char *stack; int nr = entry->nr; callchain_store(entry, instruction_pointer(regs)); stack = ((char *)regs + sizeof(struct pt_regs)); #ifdef CONFIG_FRAME_POINTER bp = frame_pointer(regs); #else bp = 0; #endif dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, entry); entry->kernel = entry->nr - nr; } struct stack_frame { const void __user *next_fp; unsigned long return_address; }; static int copy_stack_frame(const void __user *fp, struct stack_frame *frame) { int ret; if (!access_ok(VERIFY_READ, fp, sizeof(*frame))) return 0; ret = 1; pagefault_disable(); if (__copy_from_user_inatomic(frame, fp, sizeof(*frame))) ret = 0; pagefault_enable(); return ret; } static void perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry) { struct stack_frame frame; const void __user *fp; int nr = entry->nr; regs = (struct pt_regs *)current->thread.sp0 - 1; fp = (void __user *)regs->bp; callchain_store(entry, regs->ip); while (entry->nr < MAX_STACK_DEPTH) { frame.next_fp = NULL; frame.return_address = 0; if (!copy_stack_frame(fp, &frame)) break; if ((unsigned long)fp < user_stack_pointer(regs)) break; callchain_store(entry, frame.return_address); fp = frame.next_fp; } entry->user = entry->nr - nr; } static void perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry) { int is_user; if (!regs) return; is_user = user_mode(regs); if (!current || current->pid == 0) return; if (is_user && current->state != TASK_RUNNING) return; if (!is_user) perf_callchain_kernel(regs, entry); if (current->mm) perf_callchain_user(regs, entry); } struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) { struct perf_callchain_entry *entry; if (in_nmi()) entry = &__get_cpu_var(nmi_entry); else entry = &__get_cpu_var(irq_entry); entry->nr = 0; entry->hv = 0; entry->kernel = 0; entry->user = 0; perf_do_callchain(regs, entry); return entry; }