diff options
Diffstat (limited to 'arch/x86/kernel/cpu/perf_counter.c')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c new file mode 100644 index 00000000000..82440cbed0e --- /dev/null +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -0,0 +1,571 @@ +/* + * Performance counter x86 architecture code + * + * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de> + * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar + * + * For licencing details see kernel-base/COPYING + */ + +#include <linux/perf_counter.h> +#include <linux/capability.h> +#include <linux/notifier.h> +#include <linux/hardirq.h> +#include <linux/kprobes.h> +#include <linux/kdebug.h> +#include <linux/sched.h> + +#include <asm/intel_arch_perfmon.h> +#include <asm/apic.h> + +static bool perf_counters_initialized __read_mostly; + +/* + * Number of (generic) HW counters: + */ +static int nr_hw_counters __read_mostly; +static u32 perf_counter_mask __read_mostly; + +/* No support for fixed function counters yet */ + +#define MAX_HW_COUNTERS 8 + +struct cpu_hw_counters { + struct perf_counter *counters[MAX_HW_COUNTERS]; + unsigned long used[BITS_TO_LONGS(MAX_HW_COUNTERS)]; + int enable_all; +}; + +/* + * Intel PerfMon v3. Used on Core2 and later. + */ +static DEFINE_PER_CPU(struct cpu_hw_counters, cpu_hw_counters); + +const int intel_perfmon_event_map[] = +{ + [PERF_COUNT_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, +}; + +const int max_intel_perfmon_events = ARRAY_SIZE(intel_perfmon_event_map); + +/* + * Setup the hardware configuration for a given hw_event_type + */ +int hw_perf_counter_init(struct perf_counter *counter, s32 hw_event_type) +{ + struct hw_perf_counter *hwc = &counter->hw; + + if (unlikely(!perf_counters_initialized)) + return -EINVAL; + + /* + * Count user events, and generate PMC IRQs: + * (keep 'enabled' bit clear for now) + */ + hwc->config = ARCH_PERFMON_EVENTSEL_USR | ARCH_PERFMON_EVENTSEL_INT; + + /* + * If privileged enough, count OS events too, and allow + * NMI events as well: + */ + hwc->nmi = 0; + if (capable(CAP_SYS_ADMIN)) { + hwc->config |= ARCH_PERFMON_EVENTSEL_OS; + if (hw_event_type & PERF_COUNT_NMI) + hwc->nmi = 1; + } + + hwc->config_base = MSR_ARCH_PERFMON_EVENTSEL0; + hwc->counter_base = MSR_ARCH_PERFMON_PERFCTR0; + + hwc->irq_period = counter->__irq_period; + /* + * Intel PMCs cannot be accessed sanely above 32 bit width, + * so we install an artificial 1<<31 period regardless of + * the generic counter period: + */ + if (!hwc->irq_period) + hwc->irq_period = 0x7FFFFFFF; + + hwc->next_count = -((s32) hwc->irq_period); + + /* + * Negative event types mean raw encoded event+umask values: + */ + if (hw_event_type < 0) { + counter->hw_event_type = -hw_event_type; + counter->hw_event_type &= ~PERF_COUNT_NMI; + } else { + hw_event_type &= ~PERF_COUNT_NMI; + if (hw_event_type >= max_intel_perfmon_events) + return -EINVAL; + /* + * The generic map: + */ + counter->hw_event_type = intel_perfmon_event_map[hw_event_type]; + } + hwc->config |= counter->hw_event_type; + counter->wakeup_pending = 0; + + return 0; +} + +static void __hw_perf_enable_all(void) +{ + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask, 0); +} + +void hw_perf_enable_all(void) +{ + struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); + + cpuc->enable_all = 1; + __hw_perf_enable_all(); +} + +void hw_perf_disable_all(void) +{ + struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); + + cpuc->enable_all = 0; + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0); +} + +static DEFINE_PER_CPU(u64, prev_next_count[MAX_HW_COUNTERS]); + +static void __hw_perf_counter_enable(struct hw_perf_counter *hwc, int idx) +{ + per_cpu(prev_next_count[idx], smp_processor_id()) = hwc->next_count; + + wrmsr(hwc->counter_base + idx, hwc->next_count, 0); + wrmsr(hwc->config_base + idx, hwc->config, 0); +} + +void hw_perf_counter_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 = hwc->idx; + + /* Try to get the previous counter again */ + if (test_and_set_bit(idx, cpuc->used)) { + idx = find_first_zero_bit(cpuc->used, nr_hw_counters); + set_bit(idx, cpuc->used); + hwc->idx = idx; + } + + perf_counters_lapic_init(hwc->nmi); + + wrmsr(hwc->config_base + idx, + hwc->config & ~ARCH_PERFMON_EVENTSEL0_ENABLE, 0); + + cpuc->counters[idx] = counter; + counter->hw.config |= ARCH_PERFMON_EVENTSEL0_ENABLE; + __hw_perf_counter_enable(hwc, idx); +} + +#ifdef CONFIG_X86_64 +static inline void atomic64_counter_set(struct perf_counter *counter, u64 val) +{ + atomic64_set(&counter->count, val); +} + +static inline u64 atomic64_counter_read(struct perf_counter *counter) +{ + return atomic64_read(&counter->count); +} +#else +/* + * Todo: add proper atomic64_t support to 32-bit x86: + */ +static inline void atomic64_counter_set(struct perf_counter *counter, u64 val64) +{ + u32 *val32 = (void *)&val64; + + atomic_set(counter->count32 + 0, *(val32 + 0)); + atomic_set(counter->count32 + 1, *(val32 + 1)); +} + +static inline u64 atomic64_counter_read(struct perf_counter *counter) +{ + return atomic_read(counter->count32 + 0) | + (u64) atomic_read(counter->count32 + 1) << 32; +} +#endif + +static void __hw_perf_save_counter(struct perf_counter *counter, + struct hw_perf_counter *hwc, int idx) +{ + s64 raw = -1; + s64 delta; + int err; + + /* + * Get the raw hw counter value: + */ + err = rdmsrl_safe(hwc->counter_base + idx, &raw); + WARN_ON_ONCE(err); + + /* + * Rebase it to zero (it started counting at -irq_period), + * to see the delta since ->prev_count: + */ + delta = (s64)hwc->irq_period + (s64)(s32)raw; + + atomic64_counter_set(counter, hwc->prev_count + delta); + + /* + * Adjust the ->prev_count offset - if we went beyond + * irq_period of units, then we got an IRQ and the counter + * was set back to -irq_period: + */ + while (delta >= (s64)hwc->irq_period) { + hwc->prev_count += hwc->irq_period; + delta -= (s64)hwc->irq_period; + } + + /* + * Calculate the next raw counter value we'll write into + * the counter at the next sched-in time: + */ + delta -= (s64)hwc->irq_period; + + hwc->next_count = (s32)delta; +} + +void perf_counter_print_debug(void) +{ + u64 ctrl, status, overflow, pmc_ctrl, pmc_count, next_count; + int cpu, err, idx; + + local_irq_disable(); + + cpu = smp_processor_id(); + + err = rdmsrl_safe(MSR_CORE_PERF_GLOBAL_CTRL, &ctrl); + WARN_ON_ONCE(err); + + err = rdmsrl_safe(MSR_CORE_PERF_GLOBAL_STATUS, &status); + WARN_ON_ONCE(err); + + err = rdmsrl_safe(MSR_CORE_PERF_GLOBAL_OVF_CTRL, &overflow); + WARN_ON_ONCE(err); + + printk(KERN_INFO "\n"); + printk(KERN_INFO "CPU#%d: ctrl: %016llx\n", cpu, ctrl); + printk(KERN_INFO "CPU#%d: status: %016llx\n", cpu, status); + printk(KERN_INFO "CPU#%d: overflow: %016llx\n", cpu, overflow); + + for (idx = 0; idx < nr_hw_counters; idx++) { + err = rdmsrl_safe(MSR_ARCH_PERFMON_EVENTSEL0 + idx, &pmc_ctrl); + WARN_ON_ONCE(err); + + err = rdmsrl_safe(MSR_ARCH_PERFMON_PERFCTR0 + idx, &pmc_count); + WARN_ON_ONCE(err); + + next_count = per_cpu(prev_next_count[idx], cpu); + + printk(KERN_INFO "CPU#%d: PMC%d ctrl: %016llx\n", + cpu, idx, pmc_ctrl); + printk(KERN_INFO "CPU#%d: PMC%d count: %016llx\n", + cpu, idx, pmc_count); + printk(KERN_INFO "CPU#%d: PMC%d next: %016llx\n", + cpu, idx, next_count); + } + local_irq_enable(); +} + +void hw_perf_counter_disable(struct perf_counter *counter) +{ + struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters); + struct hw_perf_counter *hwc = &counter->hw; + unsigned int idx = hwc->idx; + + counter->hw.config &= ~ARCH_PERFMON_EVENTSEL0_ENABLE; + wrmsr(hwc->config_base + idx, hwc->config, 0); + + clear_bit(idx, cpuc->used); + cpuc->counters[idx] = NULL; + __hw_perf_save_counter(counter, hwc, idx); +} + +void hw_perf_counter_read(struct perf_counter *counter) +{ + struct hw_perf_counter *hwc = &counter->hw; + unsigned long addr = hwc->counter_base + hwc->idx; + s64 offs, val = -1LL; + s32 val32; + int err; + + /* Careful: NMI might modify the counter offset */ + do { + offs = hwc->prev_count; + err = rdmsrl_safe(addr, &val); + WARN_ON_ONCE(err); + } while (offs != hwc->prev_count); + + val32 = (s32) val; + val = (s64)hwc->irq_period + (s64)val32; + atomic64_counter_set(counter, hwc->prev_count + val); +} + +static void perf_store_irq_data(struct perf_counter *counter, u64 data) +{ + struct perf_data *irqdata = counter->irqdata; + + if (irqdata->len > PERF_DATA_BUFLEN - sizeof(u64)) { + irqdata->overrun++; + } else { + u64 *p = (u64 *) &irqdata->data[irqdata->len]; + + *p = data; + irqdata->len += sizeof(u64); + } +} + +static void perf_save_and_restart(struct perf_counter *counter) +{ + struct hw_perf_counter *hwc = &counter->hw; + int idx = hwc->idx; + + wrmsr(hwc->config_base + idx, + hwc->config & ~ARCH_PERFMON_EVENTSEL0_ENABLE, 0); + + if (hwc->config & ARCH_PERFMON_EVENTSEL0_ENABLE) { + __hw_perf_save_counter(counter, hwc, idx); + __hw_perf_counter_enable(hwc, idx); + } +} + +static void +perf_handle_group(struct perf_counter *leader, u64 *status, u64 *overflown) +{ + struct perf_counter_context *ctx = leader->ctx; + struct perf_counter *counter; + int bit; + + list_for_each_entry(counter, &ctx->counters, list) { + if (counter->record_type != PERF_RECORD_SIMPLE || + counter == leader) + continue; + + if (counter->active) { + /* + * When counter was not in the overflow mask, we have to + * read it from hardware. We read it as well, when it + * has not been read yet and clear the bit in the + * status mask. + */ + bit = counter->hw.idx; + if (!test_bit(bit, (unsigned long *) overflown) || + test_bit(bit, (unsigned long *) status)) { + clear_bit(bit, (unsigned long *) status); + perf_save_and_restart(counter); + } + } + perf_store_irq_data(leader, counter->hw_event_type); + perf_store_irq_data(leader, atomic64_counter_read(counter)); + } +} + +/* + * This handler is triggered by the local APIC, so the APIC IRQ handling + * rules apply: + */ +static void __smp_perf_counter_interrupt(struct pt_regs *regs, int nmi) +{ + int bit, cpu = smp_processor_id(); + struct cpu_hw_counters *cpuc; + u64 ack, status; + + rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status); + if (!status) { + ack_APIC_irq(); + return; + } + + /* Disable counters globally */ + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0); + ack_APIC_irq(); + + cpuc = &per_cpu(cpu_hw_counters, cpu); + +again: + ack = status; + for_each_bit(bit, (unsigned long *) &status, nr_hw_counters) { + struct perf_counter *counter = cpuc->counters[bit]; + + clear_bit(bit, (unsigned long *) &status); + if (!counter) + continue; + + perf_save_and_restart(counter); + + switch (counter->record_type) { + case PERF_RECORD_SIMPLE: + continue; + case PERF_RECORD_IRQ: + perf_store_irq_data(counter, instruction_pointer(regs)); + break; + case PERF_RECORD_GROUP: + perf_store_irq_data(counter, counter->hw_event_type); + perf_store_irq_data(counter, + atomic64_counter_read(counter)); + perf_handle_group(counter, &status, &ack); + break; + } + /* + * From NMI context we cannot call into the scheduler to + * do a task wakeup - but we mark these counters as + * wakeup_pending and initate a wakeup callback: + */ + if (nmi) { + counter->wakeup_pending = 1; + set_tsk_thread_flag(current, TIF_PERF_COUNTERS); + } else { + wake_up(&counter->waitq); + } + } + + wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack, 0); + + /* + * Repeat if there is more work to be done: + */ + rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status); + if (status) + goto again; + + /* + * Do not reenable when global enable is off: + */ + if (cpuc->enable_all) + __hw_perf_enable_all(); +} + +void smp_perf_counter_interrupt(struct pt_regs *regs) +{ + irq_enter(); +#ifdef CONFIG_X86_64 + add_pda(apic_perf_irqs, 1); +#else + per_cpu(irq_stat, smp_processor_id()).apic_perf_irqs++; +#endif + apic_write(APIC_LVTPC, LOCAL_PERF_VECTOR); + __smp_perf_counter_interrupt(regs, 0); + + irq_exit(); +} + +/* + * This handler is triggered by NMI contexts: + */ +void perf_counter_notify(struct pt_regs *regs) +{ + struct cpu_hw_counters *cpuc; + unsigned long flags; + int bit, cpu; + + local_irq_save(flags); + cpu = smp_processor_id(); + cpuc = &per_cpu(cpu_hw_counters, cpu); + + for_each_bit(bit, cpuc->used, nr_hw_counters) { + struct perf_counter *counter = cpuc->counters[bit]; + + if (!counter) + continue; + + if (counter->wakeup_pending) { + counter->wakeup_pending = 0; + wake_up(&counter->waitq); + } + } + + local_irq_restore(flags); +} + +void __cpuinit perf_counters_lapic_init(int nmi) +{ + u32 apic_val; + + if (!perf_counters_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 (likely(cmd != DIE_NMI_IPI)) + return NOTIFY_DONE; + + regs = args->regs; + + apic_write(APIC_LVTPC, APIC_DM_NMI); + __smp_perf_counter_interrupt(regs, 1); + + return NOTIFY_STOP; +} + +static __read_mostly struct notifier_block perf_counter_nmi_notifier = { + .notifier_call = perf_counter_nmi_handler +}; + +void __init init_hw_perf_counters(void) +{ + union cpuid10_eax eax; + unsigned int unused; + unsigned int ebx; + + if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) + return; + + /* + * Check whether the Architectural PerfMon supports + * Branch Misses Retired Event or not. + */ + cpuid(10, &(eax.full), &ebx, &unused, &unused); + if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED) + return; + + printk(KERN_INFO "Intel Performance Monitoring support detected.\n"); + + printk(KERN_INFO "... version: %d\n", eax.split.version_id); + printk(KERN_INFO "... num_counters: %d\n", eax.split.num_counters); + nr_hw_counters = eax.split.num_counters; + if (nr_hw_counters > MAX_HW_COUNTERS) { + nr_hw_counters = MAX_HW_COUNTERS; + WARN(1, KERN_ERR "hw perf counters %d > max(%d), clipping!", + nr_hw_counters, MAX_HW_COUNTERS); + } + perf_counter_mask = (1 << nr_hw_counters) - 1; + perf_max_counters = nr_hw_counters; + + printk(KERN_INFO "... bit_width: %d\n", eax.split.bit_width); + printk(KERN_INFO "... mask_length: %d\n", eax.split.mask_length); + + perf_counters_lapic_init(0); + register_die_notifier(&perf_counter_nmi_notifier); + + perf_counters_initialized = true; +} |