| /* |
| * Performance events core code: |
| * |
| * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> |
| * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar |
| * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra |
| * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> |
| * |
| * For licensing details see kernel-base/COPYING |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/cpu.h> |
| #include <linux/smp.h> |
| #include <linux/idr.h> |
| #include <linux/file.h> |
| #include <linux/poll.h> |
| #include <linux/slab.h> |
| #include <linux/hash.h> |
| #include <linux/tick.h> |
| #include <linux/sysfs.h> |
| #include <linux/dcache.h> |
| #include <linux/percpu.h> |
| #include <linux/ptrace.h> |
| #include <linux/reboot.h> |
| #include <linux/vmstat.h> |
| #include <linux/device.h> |
| #include <linux/export.h> |
| #include <linux/vmalloc.h> |
| #include <linux/hardirq.h> |
| #include <linux/rculist.h> |
| #include <linux/uaccess.h> |
| #include <linux/syscalls.h> |
| #include <linux/anon_inodes.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/cgroup.h> |
| #include <linux/perf_event.h> |
| #include <linux/trace_events.h> |
| #include <linux/hw_breakpoint.h> |
| #include <linux/mm_types.h> |
| #include <linux/module.h> |
| #include <linux/mman.h> |
| #include <linux/compat.h> |
| #include <linux/bpf.h> |
| #include <linux/filter.h> |
| |
| #include "internal.h" |
| |
| #include <asm/irq_regs.h> |
| |
| typedef int (*remote_function_f)(void *); |
| |
| struct remote_function_call { |
| struct task_struct *p; |
| remote_function_f func; |
| void *info; |
| int ret; |
| }; |
| |
| static void remote_function(void *data) |
| { |
| struct remote_function_call *tfc = data; |
| struct task_struct *p = tfc->p; |
| |
| if (p) { |
| /* -EAGAIN */ |
| if (task_cpu(p) != smp_processor_id()) |
| return; |
| |
| /* |
| * Now that we're on right CPU with IRQs disabled, we can test |
| * if we hit the right task without races. |
| */ |
| |
| tfc->ret = -ESRCH; /* No such (running) process */ |
| if (p != current) |
| return; |
| } |
| |
| tfc->ret = tfc->func(tfc->info); |
| } |
| |
| /** |
| * task_function_call - call a function on the cpu on which a task runs |
| * @p: the task to evaluate |
| * @func: the function to be called |
| * @info: the function call argument |
| * |
| * Calls the function @func when the task is currently running. This might |
| * be on the current CPU, which just calls the function directly |
| * |
| * returns: @func return value, or |
| * -ESRCH - when the process isn't running |
| * -EAGAIN - when the process moved away |
| */ |
| static int |
| task_function_call(struct task_struct *p, remote_function_f func, void *info) |
| { |
| struct remote_function_call data = { |
| .p = p, |
| .func = func, |
| .info = info, |
| .ret = -EAGAIN, |
| }; |
| int ret; |
| |
| do { |
| ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); |
| if (!ret) |
| ret = data.ret; |
| } while (ret == -EAGAIN); |
| |
| return ret; |
| } |
| |
| /** |
| * cpu_function_call - call a function on the cpu |
| * @func: the function to be called |
| * @info: the function call argument |
| * |
| * Calls the function @func on the remote cpu. |
| * |
| * returns: @func return value or -ENXIO when the cpu is offline |
| */ |
| static int cpu_function_call(int cpu, remote_function_f func, void *info) |
| { |
| struct remote_function_call data = { |
| .p = NULL, |
| .func = func, |
| .info = info, |
| .ret = -ENXIO, /* No such CPU */ |
| }; |
| |
| smp_call_function_single(cpu, remote_function, &data, 1); |
| |
| return data.ret; |
| } |
| |
| static inline struct perf_cpu_context * |
| __get_cpu_context(struct perf_event_context *ctx) |
| { |
| return this_cpu_ptr(ctx->pmu->pmu_cpu_context); |
| } |
| |
| static void perf_ctx_lock(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| raw_spin_lock(&cpuctx->ctx.lock); |
| if (ctx) |
| raw_spin_lock(&ctx->lock); |
| } |
| |
| static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| if (ctx) |
| raw_spin_unlock(&ctx->lock); |
| raw_spin_unlock(&cpuctx->ctx.lock); |
| } |
| |
| #define TASK_TOMBSTONE ((void *)-1L) |
| |
| static bool is_kernel_event(struct perf_event *event) |
| { |
| return READ_ONCE(event->owner) == TASK_TOMBSTONE; |
| } |
| |
| /* |
| * On task ctx scheduling... |
| * |
| * When !ctx->nr_events a task context will not be scheduled. This means |
| * we can disable the scheduler hooks (for performance) without leaving |
| * pending task ctx state. |
| * |
| * This however results in two special cases: |
| * |
| * - removing the last event from a task ctx; this is relatively straight |
| * forward and is done in __perf_remove_from_context. |
| * |
| * - adding the first event to a task ctx; this is tricky because we cannot |
| * rely on ctx->is_active and therefore cannot use event_function_call(). |
| * See perf_install_in_context(). |
| * |
| * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. |
| */ |
| |
| typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, |
| struct perf_event_context *, void *); |
| |
| struct event_function_struct { |
| struct perf_event *event; |
| event_f func; |
| void *data; |
| }; |
| |
| static int event_function(void *info) |
| { |
| struct event_function_struct *efs = info; |
| struct perf_event *event = efs->event; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| struct perf_event_context *task_ctx = cpuctx->task_ctx; |
| int ret = 0; |
| |
| WARN_ON_ONCE(!irqs_disabled()); |
| |
| perf_ctx_lock(cpuctx, task_ctx); |
| /* |
| * Since we do the IPI call without holding ctx->lock things can have |
| * changed, double check we hit the task we set out to hit. |
| */ |
| if (ctx->task) { |
| if (ctx->task != current) { |
| ret = -ESRCH; |
| goto unlock; |
| } |
| |
| /* |
| * We only use event_function_call() on established contexts, |
| * and event_function() is only ever called when active (or |
| * rather, we'll have bailed in task_function_call() or the |
| * above ctx->task != current test), therefore we must have |
| * ctx->is_active here. |
| */ |
| WARN_ON_ONCE(!ctx->is_active); |
| /* |
| * And since we have ctx->is_active, cpuctx->task_ctx must |
| * match. |
| */ |
| WARN_ON_ONCE(task_ctx != ctx); |
| } else { |
| WARN_ON_ONCE(&cpuctx->ctx != ctx); |
| } |
| |
| efs->func(event, cpuctx, ctx, efs->data); |
| unlock: |
| perf_ctx_unlock(cpuctx, task_ctx); |
| |
| return ret; |
| } |
| |
| static void event_function_local(struct perf_event *event, event_f func, void *data) |
| { |
| struct event_function_struct efs = { |
| .event = event, |
| .func = func, |
| .data = data, |
| }; |
| |
| int ret = event_function(&efs); |
| WARN_ON_ONCE(ret); |
| } |
| |
| static void event_function_call(struct perf_event *event, event_f func, void *data) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ |
| struct event_function_struct efs = { |
| .event = event, |
| .func = func, |
| .data = data, |
| }; |
| |
| if (!event->parent) { |
| /* |
| * If this is a !child event, we must hold ctx::mutex to |
| * stabilize the the event->ctx relation. See |
| * perf_event_ctx_lock(). |
| */ |
| lockdep_assert_held(&ctx->mutex); |
| } |
| |
| if (!task) { |
| cpu_function_call(event->cpu, event_function, &efs); |
| return; |
| } |
| |
| if (task == TASK_TOMBSTONE) |
| return; |
| |
| again: |
| if (!task_function_call(task, event_function, &efs)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| /* |
| * Reload the task pointer, it might have been changed by |
| * a concurrent perf_event_context_sched_out(). |
| */ |
| task = ctx->task; |
| if (task == TASK_TOMBSTONE) { |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| if (ctx->is_active) { |
| raw_spin_unlock_irq(&ctx->lock); |
| goto again; |
| } |
| func(event, NULL, ctx, data); |
| raw_spin_unlock_irq(&ctx->lock); |
| } |
| |
| #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ |
| PERF_FLAG_FD_OUTPUT |\ |
| PERF_FLAG_PID_CGROUP |\ |
| PERF_FLAG_FD_CLOEXEC) |
| |
| /* |
| * branch priv levels that need permission checks |
| */ |
| #define PERF_SAMPLE_BRANCH_PERM_PLM \ |
| (PERF_SAMPLE_BRANCH_KERNEL |\ |
| PERF_SAMPLE_BRANCH_HV) |
| |
| enum event_type_t { |
| EVENT_FLEXIBLE = 0x1, |
| EVENT_PINNED = 0x2, |
| EVENT_TIME = 0x4, |
| EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, |
| }; |
| |
| /* |
| * perf_sched_events : >0 events exist |
| * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu |
| */ |
| |
| static void perf_sched_delayed(struct work_struct *work); |
| DEFINE_STATIC_KEY_FALSE(perf_sched_events); |
| static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); |
| static DEFINE_MUTEX(perf_sched_mutex); |
| static atomic_t perf_sched_count; |
| |
| static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); |
| static DEFINE_PER_CPU(int, perf_sched_cb_usages); |
| |
| static atomic_t nr_mmap_events __read_mostly; |
| static atomic_t nr_comm_events __read_mostly; |
| static atomic_t nr_task_events __read_mostly; |
| static atomic_t nr_freq_events __read_mostly; |
| static atomic_t nr_switch_events __read_mostly; |
| |
| static LIST_HEAD(pmus); |
| static DEFINE_MUTEX(pmus_lock); |
| static struct srcu_struct pmus_srcu; |
| |
| /* |
| * perf event paranoia level: |
| * -1 - not paranoid at all |
| * 0 - disallow raw tracepoint access for unpriv |
| * 1 - disallow cpu events for unpriv |
| * 2 - disallow kernel profiling for unpriv |
| */ |
| int sysctl_perf_event_paranoid __read_mostly = 1; |
| |
| /* Minimum for 512 kiB + 1 user control page */ |
| int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ |
| |
| /* |
| * max perf event sample rate |
| */ |
| #define DEFAULT_MAX_SAMPLE_RATE 100000 |
| #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) |
| #define DEFAULT_CPU_TIME_MAX_PERCENT 25 |
| |
| int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; |
| |
| static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); |
| static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; |
| |
| static int perf_sample_allowed_ns __read_mostly = |
| DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; |
| |
| static void update_perf_cpu_limits(void) |
| { |
| u64 tmp = perf_sample_period_ns; |
| |
| tmp *= sysctl_perf_cpu_time_max_percent; |
| tmp = div_u64(tmp, 100); |
| if (!tmp) |
| tmp = 1; |
| |
| WRITE_ONCE(perf_sample_allowed_ns, tmp); |
| } |
| |
| static int perf_rotate_context(struct perf_cpu_context *cpuctx); |
| |
| int perf_proc_update_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
| |
| if (ret || !write) |
| return ret; |
| |
| max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); |
| perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; |
| update_perf_cpu_limits(); |
| |
| return 0; |
| } |
| |
| int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; |
| |
| int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| int ret = proc_dointvec(table, write, buffer, lenp, ppos); |
| |
| if (ret || !write) |
| return ret; |
| |
| if (sysctl_perf_cpu_time_max_percent == 100) { |
| printk(KERN_WARNING |
| "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); |
| WRITE_ONCE(perf_sample_allowed_ns, 0); |
| } else { |
| update_perf_cpu_limits(); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * perf samples are done in some very critical code paths (NMIs). |
| * If they take too much CPU time, the system can lock up and not |
| * get any real work done. This will drop the sample rate when |
| * we detect that events are taking too long. |
| */ |
| #define NR_ACCUMULATED_SAMPLES 128 |
| static DEFINE_PER_CPU(u64, running_sample_length); |
| |
| static u64 __report_avg; |
| static u64 __report_allowed; |
| |
| static void perf_duration_warn(struct irq_work *w) |
| { |
| printk_ratelimited(KERN_WARNING |
| "perf: interrupt took too long (%lld > %lld), lowering " |
| "kernel.perf_event_max_sample_rate to %d\n", |
| __report_avg, __report_allowed, |
| sysctl_perf_event_sample_rate); |
| } |
| |
| static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); |
| |
| void perf_sample_event_took(u64 sample_len_ns) |
| { |
| u64 max_len = READ_ONCE(perf_sample_allowed_ns); |
| u64 running_len; |
| u64 avg_len; |
| u32 max; |
| |
| if (max_len == 0) |
| return; |
| |
| /* Decay the counter by 1 average sample. */ |
| running_len = __this_cpu_read(running_sample_length); |
| running_len -= running_len/NR_ACCUMULATED_SAMPLES; |
| running_len += sample_len_ns; |
| __this_cpu_write(running_sample_length, running_len); |
| |
| /* |
| * Note: this will be biased artifically low until we have |
| * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us |
| * from having to maintain a count. |
| */ |
| avg_len = running_len/NR_ACCUMULATED_SAMPLES; |
| if (avg_len <= max_len) |
| return; |
| |
| __report_avg = avg_len; |
| __report_allowed = max_len; |
| |
| /* |
| * Compute a throttle threshold 25% below the current duration. |
| */ |
| avg_len += avg_len / 4; |
| max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; |
| if (avg_len < max) |
| max /= (u32)avg_len; |
| else |
| max = 1; |
| |
| WRITE_ONCE(perf_sample_allowed_ns, avg_len); |
| WRITE_ONCE(max_samples_per_tick, max); |
| |
| sysctl_perf_event_sample_rate = max * HZ; |
| perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; |
| |
| if (!irq_work_queue(&perf_duration_work)) { |
| early_printk("perf: interrupt took too long (%lld > %lld), lowering " |
| "kernel.perf_event_max_sample_rate to %d\n", |
| __report_avg, __report_allowed, |
| sysctl_perf_event_sample_rate); |
| } |
| } |
| |
| static atomic64_t perf_event_id; |
| |
| static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type); |
| |
| static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task); |
| |
| static void update_context_time(struct perf_event_context *ctx); |
| static u64 perf_event_time(struct perf_event *event); |
| |
| void __weak perf_event_print_debug(void) { } |
| |
| extern __weak const char *perf_pmu_name(void) |
| { |
| return "pmu"; |
| } |
| |
| static inline u64 perf_clock(void) |
| { |
| return local_clock(); |
| } |
| |
| static inline u64 perf_event_clock(struct perf_event *event) |
| { |
| return event->clock(); |
| } |
| |
| #ifdef CONFIG_CGROUP_PERF |
| |
| static inline bool |
| perf_cgroup_match(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| |
| /* @event doesn't care about cgroup */ |
| if (!event->cgrp) |
| return true; |
| |
| /* wants specific cgroup scope but @cpuctx isn't associated with any */ |
| if (!cpuctx->cgrp) |
| return false; |
| |
| /* |
| * Cgroup scoping is recursive. An event enabled for a cgroup is |
| * also enabled for all its descendant cgroups. If @cpuctx's |
| * cgroup is a descendant of @event's (the test covers identity |
| * case), it's a match. |
| */ |
| return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, |
| event->cgrp->css.cgroup); |
| } |
| |
| static inline void perf_detach_cgroup(struct perf_event *event) |
| { |
| css_put(&event->cgrp->css); |
| event->cgrp = NULL; |
| } |
| |
| static inline int is_cgroup_event(struct perf_event *event) |
| { |
| return event->cgrp != NULL; |
| } |
| |
| static inline u64 perf_cgroup_event_time(struct perf_event *event) |
| { |
| struct perf_cgroup_info *t; |
| |
| t = per_cpu_ptr(event->cgrp->info, event->cpu); |
| return t->time; |
| } |
| |
| static inline void __update_cgrp_time(struct perf_cgroup *cgrp) |
| { |
| struct perf_cgroup_info *info; |
| u64 now; |
| |
| now = perf_clock(); |
| |
| info = this_cpu_ptr(cgrp->info); |
| |
| info->time += now - info->timestamp; |
| info->timestamp = now; |
| } |
| |
| static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) |
| { |
| struct perf_cgroup *cgrp_out = cpuctx->cgrp; |
| if (cgrp_out) |
| __update_cgrp_time(cgrp_out); |
| } |
| |
| static inline void update_cgrp_time_from_event(struct perf_event *event) |
| { |
| struct perf_cgroup *cgrp; |
| |
| /* |
| * ensure we access cgroup data only when needed and |
| * when we know the cgroup is pinned (css_get) |
| */ |
| if (!is_cgroup_event(event)) |
| return; |
| |
| cgrp = perf_cgroup_from_task(current, event->ctx); |
| /* |
| * Do not update time when cgroup is not active |
| */ |
| if (cgrp == event->cgrp) |
| __update_cgrp_time(event->cgrp); |
| } |
| |
| static inline void |
| perf_cgroup_set_timestamp(struct task_struct *task, |
| struct perf_event_context *ctx) |
| { |
| struct perf_cgroup *cgrp; |
| struct perf_cgroup_info *info; |
| |
| /* |
| * ctx->lock held by caller |
| * ensure we do not access cgroup data |
| * unless we have the cgroup pinned (css_get) |
| */ |
| if (!task || !ctx->nr_cgroups) |
| return; |
| |
| cgrp = perf_cgroup_from_task(task, ctx); |
| info = this_cpu_ptr(cgrp->info); |
| info->timestamp = ctx->timestamp; |
| } |
| |
| #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ |
| #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ |
| |
| /* |
| * reschedule events based on the cgroup constraint of task. |
| * |
| * mode SWOUT : schedule out everything |
| * mode SWIN : schedule in based on cgroup for next |
| */ |
| static void perf_cgroup_switch(struct task_struct *task, int mode) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct pmu *pmu; |
| unsigned long flags; |
| |
| /* |
| * disable interrupts to avoid geting nr_cgroup |
| * changes via __perf_event_disable(). Also |
| * avoids preemption. |
| */ |
| local_irq_save(flags); |
| |
| /* |
| * we reschedule only in the presence of cgroup |
| * constrained events. |
| */ |
| |
| list_for_each_entry_rcu(pmu, &pmus, entry) { |
| cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| if (cpuctx->unique_pmu != pmu) |
| continue; /* ensure we process each cpuctx once */ |
| |
| /* |
| * perf_cgroup_events says at least one |
| * context on this CPU has cgroup events. |
| * |
| * ctx->nr_cgroups reports the number of cgroup |
| * events for a context. |
| */ |
| if (cpuctx->ctx.nr_cgroups > 0) { |
| perf_ctx_lock(cpuctx, cpuctx->task_ctx); |
| perf_pmu_disable(cpuctx->ctx.pmu); |
| |
| if (mode & PERF_CGROUP_SWOUT) { |
| cpu_ctx_sched_out(cpuctx, EVENT_ALL); |
| /* |
| * must not be done before ctxswout due |
| * to event_filter_match() in event_sched_out() |
| */ |
| cpuctx->cgrp = NULL; |
| } |
| |
| if (mode & PERF_CGROUP_SWIN) { |
| WARN_ON_ONCE(cpuctx->cgrp); |
| /* |
| * set cgrp before ctxsw in to allow |
| * event_filter_match() to not have to pass |
| * task around |
| * we pass the cpuctx->ctx to perf_cgroup_from_task() |
| * because cgorup events are only per-cpu |
| */ |
| cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx); |
| cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); |
| } |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| perf_ctx_unlock(cpuctx, cpuctx->task_ctx); |
| } |
| } |
| |
| local_irq_restore(flags); |
| } |
| |
| static inline void perf_cgroup_sched_out(struct task_struct *task, |
| struct task_struct *next) |
| { |
| struct perf_cgroup *cgrp1; |
| struct perf_cgroup *cgrp2 = NULL; |
| |
| rcu_read_lock(); |
| /* |
| * we come here when we know perf_cgroup_events > 0 |
| * we do not need to pass the ctx here because we know |
| * we are holding the rcu lock |
| */ |
| cgrp1 = perf_cgroup_from_task(task, NULL); |
| cgrp2 = perf_cgroup_from_task(next, NULL); |
| |
| /* |
| * only schedule out current cgroup events if we know |
| * that we are switching to a different cgroup. Otherwise, |
| * do no touch the cgroup events. |
| */ |
| if (cgrp1 != cgrp2) |
| perf_cgroup_switch(task, PERF_CGROUP_SWOUT); |
| |
| rcu_read_unlock(); |
| } |
| |
| static inline void perf_cgroup_sched_in(struct task_struct *prev, |
| struct task_struct *task) |
| { |
| struct perf_cgroup *cgrp1; |
| struct perf_cgroup *cgrp2 = NULL; |
| |
| rcu_read_lock(); |
| /* |
| * we come here when we know perf_cgroup_events > 0 |
| * we do not need to pass the ctx here because we know |
| * we are holding the rcu lock |
| */ |
| cgrp1 = perf_cgroup_from_task(task, NULL); |
| cgrp2 = perf_cgroup_from_task(prev, NULL); |
| |
| /* |
| * only need to schedule in cgroup events if we are changing |
| * cgroup during ctxsw. Cgroup events were not scheduled |
| * out of ctxsw out if that was not the case. |
| */ |
| if (cgrp1 != cgrp2) |
| perf_cgroup_switch(task, PERF_CGROUP_SWIN); |
| |
| rcu_read_unlock(); |
| } |
| |
| static inline int perf_cgroup_connect(int fd, struct perf_event *event, |
| struct perf_event_attr *attr, |
| struct perf_event *group_leader) |
| { |
| struct perf_cgroup *cgrp; |
| struct cgroup_subsys_state *css; |
| struct fd f = fdget(fd); |
| int ret = 0; |
| |
| if (!f.file) |
| return -EBADF; |
| |
| css = css_tryget_online_from_dir(f.file->f_path.dentry, |
| &perf_event_cgrp_subsys); |
| if (IS_ERR(css)) { |
| ret = PTR_ERR(css); |
| goto out; |
| } |
| |
| cgrp = container_of(css, struct perf_cgroup, css); |
| event->cgrp = cgrp; |
| |
| /* |
| * all events in a group must monitor |
| * the same cgroup because a task belongs |
| * to only one perf cgroup at a time |
| */ |
| if (group_leader && group_leader->cgrp != cgrp) { |
| perf_detach_cgroup(event); |
| ret = -EINVAL; |
| } |
| out: |
| fdput(f); |
| return ret; |
| } |
| |
| static inline void |
| perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) |
| { |
| struct perf_cgroup_info *t; |
| t = per_cpu_ptr(event->cgrp->info, event->cpu); |
| event->shadow_ctx_time = now - t->timestamp; |
| } |
| |
| static inline void |
| perf_cgroup_defer_enabled(struct perf_event *event) |
| { |
| /* |
| * when the current task's perf cgroup does not match |
| * the event's, we need to remember to call the |
| * perf_mark_enable() function the first time a task with |
| * a matching perf cgroup is scheduled in. |
| */ |
| if (is_cgroup_event(event) && !perf_cgroup_match(event)) |
| event->cgrp_defer_enabled = 1; |
| } |
| |
| static inline void |
| perf_cgroup_mark_enabled(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *sub; |
| u64 tstamp = perf_event_time(event); |
| |
| if (!event->cgrp_defer_enabled) |
| return; |
| |
| event->cgrp_defer_enabled = 0; |
| |
| event->tstamp_enabled = tstamp - event->total_time_enabled; |
| list_for_each_entry(sub, &event->sibling_list, group_entry) { |
| if (sub->state >= PERF_EVENT_STATE_INACTIVE) { |
| sub->tstamp_enabled = tstamp - sub->total_time_enabled; |
| sub->cgrp_defer_enabled = 0; |
| } |
| } |
| } |
| #else /* !CONFIG_CGROUP_PERF */ |
| |
| static inline bool |
| perf_cgroup_match(struct perf_event *event) |
| { |
| return true; |
| } |
| |
| static inline void perf_detach_cgroup(struct perf_event *event) |
| {} |
| |
| static inline int is_cgroup_event(struct perf_event *event) |
| { |
| return 0; |
| } |
| |
| static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) |
| { |
| return 0; |
| } |
| |
| static inline void update_cgrp_time_from_event(struct perf_event *event) |
| { |
| } |
| |
| static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) |
| { |
| } |
| |
| static inline void perf_cgroup_sched_out(struct task_struct *task, |
| struct task_struct *next) |
| { |
| } |
| |
| static inline void perf_cgroup_sched_in(struct task_struct *prev, |
| struct task_struct *task) |
| { |
| } |
| |
| static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, |
| struct perf_event_attr *attr, |
| struct perf_event *group_leader) |
| { |
| return -EINVAL; |
| } |
| |
| static inline void |
| perf_cgroup_set_timestamp(struct task_struct *task, |
| struct perf_event_context *ctx) |
| { |
| } |
| |
| void |
| perf_cgroup_switch(struct task_struct *task, struct task_struct *next) |
| { |
| } |
| |
| static inline void |
| perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) |
| { |
| } |
| |
| static inline u64 perf_cgroup_event_time(struct perf_event *event) |
| { |
| return 0; |
| } |
| |
| static inline void |
| perf_cgroup_defer_enabled(struct perf_event *event) |
| { |
| } |
| |
| static inline void |
| perf_cgroup_mark_enabled(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| } |
| #endif |
| |
| /* |
| * set default to be dependent on timer tick just |
| * like original code |
| */ |
| #define PERF_CPU_HRTIMER (1000 / HZ) |
| /* |
| * function must be called with interrupts disbled |
| */ |
| static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) |
| { |
| struct perf_cpu_context *cpuctx; |
| int rotations = 0; |
| |
| WARN_ON(!irqs_disabled()); |
| |
| cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); |
| rotations = perf_rotate_context(cpuctx); |
| |
| raw_spin_lock(&cpuctx->hrtimer_lock); |
| if (rotations) |
| hrtimer_forward_now(hr, cpuctx->hrtimer_interval); |
| else |
| cpuctx->hrtimer_active = 0; |
| raw_spin_unlock(&cpuctx->hrtimer_lock); |
| |
| return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; |
| } |
| |
| static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) |
| { |
| struct hrtimer *timer = &cpuctx->hrtimer; |
| struct pmu *pmu = cpuctx->ctx.pmu; |
| u64 interval; |
| |
| /* no multiplexing needed for SW PMU */ |
| if (pmu->task_ctx_nr == perf_sw_context) |
| return; |
| |
| /* |
| * check default is sane, if not set then force to |
| * default interval (1/tick) |
| */ |
| interval = pmu->hrtimer_interval_ms; |
| if (interval < 1) |
| interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; |
| |
| cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); |
| |
| raw_spin_lock_init(&cpuctx->hrtimer_lock); |
| hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); |
| timer->function = perf_mux_hrtimer_handler; |
| } |
| |
| static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) |
| { |
| struct hrtimer *timer = &cpuctx->hrtimer; |
| struct pmu *pmu = cpuctx->ctx.pmu; |
| unsigned long flags; |
| |
| /* not for SW PMU */ |
| if (pmu->task_ctx_nr == perf_sw_context) |
| return 0; |
| |
| raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); |
| if (!cpuctx->hrtimer_active) { |
| cpuctx->hrtimer_active = 1; |
| hrtimer_forward_now(timer, cpuctx->hrtimer_interval); |
| hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); |
| } |
| raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); |
| |
| return 0; |
| } |
| |
| void perf_pmu_disable(struct pmu *pmu) |
| { |
| int *count = this_cpu_ptr(pmu->pmu_disable_count); |
| if (!(*count)++) |
| pmu->pmu_disable(pmu); |
| } |
| |
| void perf_pmu_enable(struct pmu *pmu) |
| { |
| int *count = this_cpu_ptr(pmu->pmu_disable_count); |
| if (!--(*count)) |
| pmu->pmu_enable(pmu); |
| } |
| |
| static DEFINE_PER_CPU(struct list_head, active_ctx_list); |
| |
| /* |
| * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and |
| * perf_event_task_tick() are fully serialized because they're strictly cpu |
| * affine and perf_event_ctx{activate,deactivate} are called with IRQs |
| * disabled, while perf_event_task_tick is called from IRQ context. |
| */ |
| static void perf_event_ctx_activate(struct perf_event_context *ctx) |
| { |
| struct list_head *head = this_cpu_ptr(&active_ctx_list); |
| |
| WARN_ON(!irqs_disabled()); |
| |
| WARN_ON(!list_empty(&ctx->active_ctx_list)); |
| |
| list_add(&ctx->active_ctx_list, head); |
| } |
| |
| static void perf_event_ctx_deactivate(struct perf_event_context *ctx) |
| { |
| WARN_ON(!irqs_disabled()); |
| |
| WARN_ON(list_empty(&ctx->active_ctx_list)); |
| |
| list_del_init(&ctx->active_ctx_list); |
| } |
| |
| static void get_ctx(struct perf_event_context *ctx) |
| { |
| WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); |
| } |
| |
| static void free_ctx(struct rcu_head *head) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = container_of(head, struct perf_event_context, rcu_head); |
| kfree(ctx->task_ctx_data); |
| kfree(ctx); |
| } |
| |
| static void put_ctx(struct perf_event_context *ctx) |
| { |
| if (atomic_dec_and_test(&ctx->refcount)) { |
| if (ctx->parent_ctx) |
| put_ctx(ctx->parent_ctx); |
| if (ctx->task && ctx->task != TASK_TOMBSTONE) |
| put_task_struct(ctx->task); |
| call_rcu(&ctx->rcu_head, free_ctx); |
| } |
| } |
| |
| /* |
| * Because of perf_event::ctx migration in sys_perf_event_open::move_group and |
| * perf_pmu_migrate_context() we need some magic. |
| * |
| * Those places that change perf_event::ctx will hold both |
| * perf_event_ctx::mutex of the 'old' and 'new' ctx value. |
| * |
| * Lock ordering is by mutex address. There are two other sites where |
| * perf_event_context::mutex nests and those are: |
| * |
| * - perf_event_exit_task_context() [ child , 0 ] |
| * perf_event_exit_event() |
| * put_event() [ parent, 1 ] |
| * |
| * - perf_event_init_context() [ parent, 0 ] |
| * inherit_task_group() |
| * inherit_group() |
| * inherit_event() |
| * perf_event_alloc() |
| * perf_init_event() |
| * perf_try_init_event() [ child , 1 ] |
| * |
| * While it appears there is an obvious deadlock here -- the parent and child |
| * nesting levels are inverted between the two. This is in fact safe because |
| * life-time rules separate them. That is an exiting task cannot fork, and a |
| * spawning task cannot (yet) exit. |
| * |
| * But remember that that these are parent<->child context relations, and |
| * migration does not affect children, therefore these two orderings should not |
| * interact. |
| * |
| * The change in perf_event::ctx does not affect children (as claimed above) |
| * because the sys_perf_event_open() case will install a new event and break |
| * the ctx parent<->child relation, and perf_pmu_migrate_context() is only |
| * concerned with cpuctx and that doesn't have children. |
| * |
| * The places that change perf_event::ctx will issue: |
| * |
| * perf_remove_from_context(); |
| * synchronize_rcu(); |
| * perf_install_in_context(); |
| * |
| * to affect the change. The remove_from_context() + synchronize_rcu() should |
| * quiesce the event, after which we can install it in the new location. This |
| * means that only external vectors (perf_fops, prctl) can perturb the event |
| * while in transit. Therefore all such accessors should also acquire |
| * perf_event_context::mutex to serialize against this. |
| * |
| * However; because event->ctx can change while we're waiting to acquire |
| * ctx->mutex we must be careful and use the below perf_event_ctx_lock() |
| * function. |
| * |
| * Lock order: |
| * task_struct::perf_event_mutex |
| * perf_event_context::mutex |
| * perf_event::child_mutex; |
| * perf_event_context::lock |
| * perf_event::mmap_mutex |
| * mmap_sem |
| */ |
| static struct perf_event_context * |
| perf_event_ctx_lock_nested(struct perf_event *event, int nesting) |
| { |
| struct perf_event_context *ctx; |
| |
| again: |
| rcu_read_lock(); |
| ctx = ACCESS_ONCE(event->ctx); |
| if (!atomic_inc_not_zero(&ctx->refcount)) { |
| rcu_read_unlock(); |
| goto again; |
| } |
| rcu_read_unlock(); |
| |
| mutex_lock_nested(&ctx->mutex, nesting); |
| if (event->ctx != ctx) { |
| mutex_unlock(&ctx->mutex); |
| put_ctx(ctx); |
| goto again; |
| } |
| |
| return ctx; |
| } |
| |
| static inline struct perf_event_context * |
| perf_event_ctx_lock(struct perf_event *event) |
| { |
| return perf_event_ctx_lock_nested(event, 0); |
| } |
| |
| static void perf_event_ctx_unlock(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| mutex_unlock(&ctx->mutex); |
| put_ctx(ctx); |
| } |
| |
| /* |
| * This must be done under the ctx->lock, such as to serialize against |
| * context_equiv(), therefore we cannot call put_ctx() since that might end up |
| * calling scheduler related locks and ctx->lock nests inside those. |
| */ |
| static __must_check struct perf_event_context * |
| unclone_ctx(struct perf_event_context *ctx) |
| { |
| struct perf_event_context *parent_ctx = ctx->parent_ctx; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (parent_ctx) |
| ctx->parent_ctx = NULL; |
| ctx->generation++; |
| |
| return parent_ctx; |
| } |
| |
| static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) |
| { |
| /* |
| * only top level events have the pid namespace they were created in |
| */ |
| if (event->parent) |
| event = event->parent; |
| |
| return task_tgid_nr_ns(p, event->ns); |
| } |
| |
| static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) |
| { |
| /* |
| * only top level events have the pid namespace they were created in |
| */ |
| if (event->parent) |
| event = event->parent; |
| |
| return task_pid_nr_ns(p, event->ns); |
| } |
| |
| /* |
| * If we inherit events we want to return the parent event id |
| * to userspace. |
| */ |
| static u64 primary_event_id(struct perf_event *event) |
| { |
| u64 id = event->id; |
| |
| if (event->parent) |
| id = event->parent->id; |
| |
| return id; |
| } |
| |
| /* |
| * Get the perf_event_context for a task and lock it. |
| * |
| * This has to cope with with the fact that until it is locked, |
| * the context could get moved to another task. |
| */ |
| static struct perf_event_context * |
| perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) |
| { |
| struct perf_event_context *ctx; |
| |
| retry: |
| /* |
| * One of the few rules of preemptible RCU is that one cannot do |
| * rcu_read_unlock() while holding a scheduler (or nested) lock when |
| * part of the read side critical section was irqs-enabled -- see |
| * rcu_read_unlock_special(). |
| * |
| * Since ctx->lock nests under rq->lock we must ensure the entire read |
| * side critical section has interrupts disabled. |
| */ |
| local_irq_save(*flags); |
| rcu_read_lock(); |
| ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); |
| if (ctx) { |
| /* |
| * If this context is a clone of another, it might |
| * get swapped for another underneath us by |
| * perf_event_task_sched_out, though the |
| * rcu_read_lock() protects us from any context |
| * getting freed. Lock the context and check if it |
| * got swapped before we could get the lock, and retry |
| * if so. If we locked the right context, then it |
| * can't get swapped on us any more. |
| */ |
| raw_spin_lock(&ctx->lock); |
| if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { |
| raw_spin_unlock(&ctx->lock); |
| rcu_read_unlock(); |
| local_irq_restore(*flags); |
| goto retry; |
| } |
| |
| if (ctx->task == TASK_TOMBSTONE || |
| !atomic_inc_not_zero(&ctx->refcount)) { |
| raw_spin_unlock(&ctx->lock); |
| ctx = NULL; |
| } else { |
| WARN_ON_ONCE(ctx->task != task); |
| } |
| } |
| rcu_read_unlock(); |
| if (!ctx) |
| local_irq_restore(*flags); |
| return ctx; |
| } |
| |
| /* |
| * Get the context for a task and increment its pin_count so it |
| * can't get swapped to another task. This also increments its |
| * reference count so that the context can't get freed. |
| */ |
| static struct perf_event_context * |
| perf_pin_task_context(struct task_struct *task, int ctxn) |
| { |
| struct perf_event_context *ctx; |
| unsigned long flags; |
| |
| ctx = perf_lock_task_context(task, ctxn, &flags); |
| if (ctx) { |
| ++ctx->pin_count; |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| } |
| return ctx; |
| } |
| |
| static void perf_unpin_context(struct perf_event_context *ctx) |
| { |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&ctx->lock, flags); |
| --ctx->pin_count; |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| } |
| |
| /* |
| * Update the record of the current time in a context. |
| */ |
| static void update_context_time(struct perf_event_context *ctx) |
| { |
| u64 now = perf_clock(); |
| |
| ctx->time += now - ctx->timestamp; |
| ctx->timestamp = now; |
| } |
| |
| static u64 perf_event_time(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| if (is_cgroup_event(event)) |
| return perf_cgroup_event_time(event); |
| |
| return ctx ? ctx->time : 0; |
| } |
| |
| /* |
| * Update the total_time_enabled and total_time_running fields for a event. |
| */ |
| static void update_event_times(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| u64 run_end; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (event->state < PERF_EVENT_STATE_INACTIVE || |
| event->group_leader->state < PERF_EVENT_STATE_INACTIVE) |
| return; |
| |
| /* |
| * in cgroup mode, time_enabled represents |
| * the time the event was enabled AND active |
| * tasks were in the monitored cgroup. This is |
| * independent of the activity of the context as |
| * there may be a mix of cgroup and non-cgroup events. |
| * |
| * That is why we treat cgroup events differently |
| * here. |
| */ |
| if (is_cgroup_event(event)) |
| run_end = perf_cgroup_event_time(event); |
| else if (ctx->is_active) |
| run_end = ctx->time; |
| else |
| run_end = event->tstamp_stopped; |
| |
| event->total_time_enabled = run_end - event->tstamp_enabled; |
| |
| if (event->state == PERF_EVENT_STATE_INACTIVE) |
| run_end = event->tstamp_stopped; |
| else |
| run_end = perf_event_time(event); |
| |
| event->total_time_running = run_end - event->tstamp_running; |
| |
| } |
| |
| /* |
| * Update total_time_enabled and total_time_running for all events in a group. |
| */ |
| static void update_group_times(struct perf_event *leader) |
| { |
| struct perf_event *event; |
| |
| update_event_times(leader); |
| list_for_each_entry(event, &leader->sibling_list, group_entry) |
| update_event_times(event); |
| } |
| |
| static struct list_head * |
| ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) |
| { |
| if (event->attr.pinned) |
| return &ctx->pinned_groups; |
| else |
| return &ctx->flexible_groups; |
| } |
| |
| /* |
| * Add a event from the lists for its context. |
| * Must be called with ctx->mutex and ctx->lock held. |
| */ |
| static void |
| list_add_event(struct perf_event *event, struct perf_event_context *ctx) |
| { |
| lockdep_assert_held(&ctx->lock); |
| |
| WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); |
| event->attach_state |= PERF_ATTACH_CONTEXT; |
| |
| /* |
| * If we're a stand alone event or group leader, we go to the context |
| * list, group events are kept attached to the group so that |
| * perf_group_detach can, at all times, locate all siblings. |
| */ |
| if (event->group_leader == event) { |
| struct list_head *list; |
| |
| if (is_software_event(event)) |
| event->group_flags |= PERF_GROUP_SOFTWARE; |
| |
| list = ctx_group_list(event, ctx); |
| list_add_tail(&event->group_entry, list); |
| } |
| |
| if (is_cgroup_event(event)) |
| ctx->nr_cgroups++; |
| |
| list_add_rcu(&event->event_entry, &ctx->event_list); |
| ctx->nr_events++; |
| if (event->attr.inherit_stat) |
| ctx->nr_stat++; |
| |
| ctx->generation++; |
| } |
| |
| /* |
| * Initialize event state based on the perf_event_attr::disabled. |
| */ |
| static inline void perf_event__state_init(struct perf_event *event) |
| { |
| event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : |
| PERF_EVENT_STATE_INACTIVE; |
| } |
| |
| static void __perf_event_read_size(struct perf_event *event, int nr_siblings) |
| { |
| int entry = sizeof(u64); /* value */ |
| int size = 0; |
| int nr = 1; |
| |
| if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
| size += sizeof(u64); |
| |
| if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
| size += sizeof(u64); |
| |
| if (event->attr.read_format & PERF_FORMAT_ID) |
| entry += sizeof(u64); |
| |
| if (event->attr.read_format & PERF_FORMAT_GROUP) { |
| nr += nr_siblings; |
| size += sizeof(u64); |
| } |
| |
| size += entry * nr; |
| event->read_size = size; |
| } |
| |
| static void __perf_event_header_size(struct perf_event *event, u64 sample_type) |
| { |
| struct perf_sample_data *data; |
| u16 size = 0; |
| |
| if (sample_type & PERF_SAMPLE_IP) |
| size += sizeof(data->ip); |
| |
| if (sample_type & PERF_SAMPLE_ADDR) |
| size += sizeof(data->addr); |
| |
| if (sample_type & PERF_SAMPLE_PERIOD) |
| size += sizeof(data->period); |
| |
| if (sample_type & PERF_SAMPLE_WEIGHT) |
| size += sizeof(data->weight); |
| |
| if (sample_type & PERF_SAMPLE_READ) |
| size += event->read_size; |
| |
| if (sample_type & PERF_SAMPLE_DATA_SRC) |
| size += sizeof(data->data_src.val); |
| |
| if (sample_type & PERF_SAMPLE_TRANSACTION) |
| size += sizeof(data->txn); |
| |
| event->header_size = size; |
| } |
| |
| /* |
| * Called at perf_event creation and when events are attached/detached from a |
| * group. |
| */ |
| static void perf_event__header_size(struct perf_event *event) |
| { |
| __perf_event_read_size(event, |
| event->group_leader->nr_siblings); |
| __perf_event_header_size(event, event->attr.sample_type); |
| } |
| |
| static void perf_event__id_header_size(struct perf_event *event) |
| { |
| struct perf_sample_data *data; |
| u64 sample_type = event->attr.sample_type; |
| u16 size = 0; |
| |
| if (sample_type & PERF_SAMPLE_TID) |
| size += sizeof(data->tid_entry); |
| |
| if (sample_type & PERF_SAMPLE_TIME) |
| size += sizeof(data->time); |
| |
| if (sample_type & PERF_SAMPLE_IDENTIFIER) |
| size += sizeof(data->id); |
| |
| if (sample_type & PERF_SAMPLE_ID) |
| size += sizeof(data->id); |
| |
| if (sample_type & PERF_SAMPLE_STREAM_ID) |
| size += sizeof(data->stream_id); |
| |
| if (sample_type & PERF_SAMPLE_CPU) |
| size += sizeof(data->cpu_entry); |
| |
| event->id_header_size = size; |
| } |
| |
| static bool perf_event_validate_size(struct perf_event *event) |
| { |
| /* |
| * The values computed here will be over-written when we actually |
| * attach the event. |
| */ |
| __perf_event_read_size(event, event->group_leader->nr_siblings + 1); |
| __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); |
| perf_event__id_header_size(event); |
| |
| /* |
| * Sum the lot; should not exceed the 64k limit we have on records. |
| * Conservative limit to allow for callchains and other variable fields. |
| */ |
| if (event->read_size + event->header_size + |
| event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) |
| return false; |
| |
| return true; |
| } |
| |
| static void perf_group_attach(struct perf_event *event) |
| { |
| struct perf_event *group_leader = event->group_leader, *pos; |
| |
| /* |
| * We can have double attach due to group movement in perf_event_open. |
| */ |
| if (event->attach_state & PERF_ATTACH_GROUP) |
| return; |
| |
| event->attach_state |= PERF_ATTACH_GROUP; |
| |
| if (group_leader == event) |
| return; |
| |
| WARN_ON_ONCE(group_leader->ctx != event->ctx); |
| |
| if (group_leader->group_flags & PERF_GROUP_SOFTWARE && |
| !is_software_event(event)) |
| group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; |
| |
| list_add_tail(&event->group_entry, &group_leader->sibling_list); |
| group_leader->nr_siblings++; |
| |
| perf_event__header_size(group_leader); |
| |
| list_for_each_entry(pos, &group_leader->sibling_list, group_entry) |
| perf_event__header_size(pos); |
| } |
| |
| /* |
| * Remove a event from the lists for its context. |
| * Must be called with ctx->mutex and ctx->lock held. |
| */ |
| static void |
| list_del_event(struct perf_event *event, struct perf_event_context *ctx) |
| { |
| struct perf_cpu_context *cpuctx; |
| |
| WARN_ON_ONCE(event->ctx != ctx); |
| lockdep_assert_held(&ctx->lock); |
| |
| /* |
| * We can have double detach due to exit/hot-unplug + close. |
| */ |
| if (!(event->attach_state & PERF_ATTACH_CONTEXT)) |
| return; |
| |
| event->attach_state &= ~PERF_ATTACH_CONTEXT; |
| |
| if (is_cgroup_event(event)) { |
| ctx->nr_cgroups--; |
| /* |
| * Because cgroup events are always per-cpu events, this will |
| * always be called from the right CPU. |
| */ |
| cpuctx = __get_cpu_context(ctx); |
| /* |
| * If there are no more cgroup events then clear cgrp to avoid |
| * stale pointer in update_cgrp_time_from_cpuctx(). |
| */ |
| if (!ctx->nr_cgroups) |
| cpuctx->cgrp = NULL; |
| } |
| |
| ctx->nr_events--; |
| if (event->attr.inherit_stat) |
| ctx->nr_stat--; |
| |
| list_del_rcu(&event->event_entry); |
| |
| if (event->group_leader == event) |
| list_del_init(&event->group_entry); |
| |
| update_group_times(event); |
| |
| /* |
| * If event was in error state, then keep it |
| * that way, otherwise bogus counts will be |
| * returned on read(). The only way to get out |
| * of error state is by explicit re-enabling |
| * of the event |
| */ |
| if (event->state > PERF_EVENT_STATE_OFF) |
| event->state = PERF_EVENT_STATE_OFF; |
| |
| ctx->generation++; |
| } |
| |
| static void perf_group_detach(struct perf_event *event) |
| { |
| struct perf_event *sibling, *tmp; |
| struct list_head *list = NULL; |
| |
| /* |
| * We can have double detach due to exit/hot-unplug + close. |
| */ |
| if (!(event->attach_state & PERF_ATTACH_GROUP)) |
| return; |
| |
| event->attach_state &= ~PERF_ATTACH_GROUP; |
| |
| /* |
| * If this is a sibling, remove it from its group. |
| */ |
| if (event->group_leader != event) { |
| list_del_init(&event->group_entry); |
| event->group_leader->nr_siblings--; |
| goto out; |
| } |
| |
| if (!list_empty(&event->group_entry)) |
| list = &event->group_entry; |
| |
| /* |
| * If this was a group event with sibling events then |
| * upgrade the siblings to singleton events by adding them |
| * to whatever list we are on. |
| */ |
| list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { |
| if (list) |
| list_move_tail(&sibling->group_entry, list); |
| sibling->group_leader = sibling; |
| |
| /* Inherit group flags from the previous leader */ |
| sibling->group_flags = event->group_flags; |
| |
| WARN_ON_ONCE(sibling->ctx != event->ctx); |
| } |
| |
| out: |
| perf_event__header_size(event->group_leader); |
| |
| list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) |
| perf_event__header_size(tmp); |
| } |
| |
| static bool is_orphaned_event(struct perf_event *event) |
| { |
| return event->state == PERF_EVENT_STATE_DEAD; |
| } |
| |
| static inline int pmu_filter_match(struct perf_event *event) |
| { |
| struct pmu *pmu = event->pmu; |
| return pmu->filter_match ? pmu->filter_match(event) : 1; |
| } |
| |
| static inline int |
| event_filter_match(struct perf_event *event) |
| { |
| return (event->cpu == -1 || event->cpu == smp_processor_id()) |
| && perf_cgroup_match(event) && pmu_filter_match(event); |
| } |
| |
| static void |
| event_sched_out(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| u64 tstamp = perf_event_time(event); |
| u64 delta; |
| |
| WARN_ON_ONCE(event->ctx != ctx); |
| lockdep_assert_held(&ctx->lock); |
| |
| /* |
| * An event which could not be activated because of |
| * filter mismatch still needs to have its timings |
| * maintained, otherwise bogus information is return |
| * via read() for time_enabled, time_running: |
| */ |
| if (event->state == PERF_EVENT_STATE_INACTIVE |
| && !event_filter_match(event)) { |
| delta = tstamp - event->tstamp_stopped; |
| event->tstamp_running += delta; |
| event->tstamp_stopped = tstamp; |
| } |
| |
| if (event->state != PERF_EVENT_STATE_ACTIVE) |
| return; |
| |
| perf_pmu_disable(event->pmu); |
| |
| event->tstamp_stopped = tstamp; |
| event->pmu->del(event, 0); |
| event->oncpu = -1; |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| if (event->pending_disable) { |
| event->pending_disable = 0; |
| event->state = PERF_EVENT_STATE_OFF; |
| } |
| |
| if (!is_software_event(event)) |
| cpuctx->active_oncpu--; |
| if (!--ctx->nr_active) |
| perf_event_ctx_deactivate(ctx); |
| if (event->attr.freq && event->attr.sample_freq) |
| ctx->nr_freq--; |
| if (event->attr.exclusive || !cpuctx->active_oncpu) |
| cpuctx->exclusive = 0; |
| |
| perf_pmu_enable(event->pmu); |
| } |
| |
| static void |
| group_sched_out(struct perf_event *group_event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *event; |
| int state = group_event->state; |
| |
| event_sched_out(group_event, cpuctx, ctx); |
| |
| /* |
| * Schedule out siblings (if any): |
| */ |
| list_for_each_entry(event, &group_event->sibling_list, group_entry) |
| event_sched_out(event, cpuctx, ctx); |
| |
| if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) |
| cpuctx->exclusive = 0; |
| } |
| |
| #define DETACH_GROUP 0x01UL |
| |
| /* |
| * Cross CPU call to remove a performance event |
| * |
| * We disable the event on the hardware level first. After that we |
| * remove it from the context list. |
| */ |
| static void |
| __perf_remove_from_context(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| void *info) |
| { |
| unsigned long flags = (unsigned long)info; |
| |
| event_sched_out(event, cpuctx, ctx); |
| if (flags & DETACH_GROUP) |
| perf_group_detach(event); |
| list_del_event(event, ctx); |
| |
| if (!ctx->nr_events && ctx->is_active) { |
| ctx->is_active = 0; |
| if (ctx->task) { |
| WARN_ON_ONCE(cpuctx->task_ctx != ctx); |
| cpuctx->task_ctx = NULL; |
| } |
| } |
| } |
| |
| /* |
| * Remove the event from a task's (or a CPU's) list of events. |
| * |
| * If event->ctx is a cloned context, callers must make sure that |
| * every task struct that event->ctx->task could possibly point to |
| * remains valid. This is OK when called from perf_release since |
| * that only calls us on the top-level context, which can't be a clone. |
| * When called from perf_event_exit_task, it's OK because the |
| * context has been detached from its task. |
| */ |
| static void perf_remove_from_context(struct perf_event *event, unsigned long flags) |
| { |
| lockdep_assert_held(&event->ctx->mutex); |
| |
| event_function_call(event, __perf_remove_from_context, (void *)flags); |
| } |
| |
| /* |
| * Cross CPU call to disable a performance event |
| */ |
| static void __perf_event_disable(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| void *info) |
| { |
| if (event->state < PERF_EVENT_STATE_INACTIVE) |
| return; |
| |
| update_context_time(ctx); |
| update_cgrp_time_from_event(event); |
| update_group_times(event); |
| if (event == event->group_leader) |
| group_sched_out(event, cpuctx, ctx); |
| else |
| event_sched_out(event, cpuctx, ctx); |
| event->state = PERF_EVENT_STATE_OFF; |
| } |
| |
| /* |
| * Disable a event. |
| * |
| * If event->ctx is a cloned context, callers must make sure that |
| * every task struct that event->ctx->task could possibly point to |
| * remains valid. This condition is satisifed when called through |
| * perf_event_for_each_child or perf_event_for_each because they |
| * hold the top-level event's child_mutex, so any descendant that |
| * goes to exit will block in perf_event_exit_event(). |
| * |
| * When called from perf_pending_event it's OK because event->ctx |
| * is the current context on this CPU and preemption is disabled, |
| * hence we can't get into perf_event_task_sched_out for this context. |
| */ |
| static void _perf_event_disable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| if (event->state <= PERF_EVENT_STATE_OFF) { |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| raw_spin_unlock_irq(&ctx->lock); |
| |
| event_function_call(event, __perf_event_disable, NULL); |
| } |
| |
| void perf_event_disable_local(struct perf_event *event) |
| { |
| event_function_local(event, __perf_event_disable, NULL); |
| } |
| |
| /* |
| * Strictly speaking kernel users cannot create groups and therefore this |
| * interface does not need the perf_event_ctx_lock() magic. |
| */ |
| void perf_event_disable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = perf_event_ctx_lock(event); |
| _perf_event_disable(event); |
| perf_event_ctx_unlock(event, ctx); |
| } |
| EXPORT_SYMBOL_GPL(perf_event_disable); |
| |
| static void perf_set_shadow_time(struct perf_event *event, |
| struct perf_event_context *ctx, |
| u64 tstamp) |
| { |
| /* |
| * use the correct time source for the time snapshot |
| * |
| * We could get by without this by leveraging the |
| * fact that to get to this function, the caller |
| * has most likely already called update_context_time() |
| * and update_cgrp_time_xx() and thus both timestamp |
| * are identical (or very close). Given that tstamp is, |
| * already adjusted for cgroup, we could say that: |
| * tstamp - ctx->timestamp |
| * is equivalent to |
| * tstamp - cgrp->timestamp. |
| * |
| * Then, in perf_output_read(), the calculation would |
| * work with no changes because: |
| * - event is guaranteed scheduled in |
| * - no scheduled out in between |
| * - thus the timestamp would be the same |
| * |
| * But this is a bit hairy. |
| * |
| * So instead, we have an explicit cgroup call to remain |
| * within the time time source all along. We believe it |
| * is cleaner and simpler to understand. |
| */ |
| if (is_cgroup_event(event)) |
| perf_cgroup_set_shadow_time(event, tstamp); |
| else |
| event->shadow_ctx_time = tstamp - ctx->timestamp; |
| } |
| |
| #define MAX_INTERRUPTS (~0ULL) |
| |
| static void perf_log_throttle(struct perf_event *event, int enable); |
| static void perf_log_itrace_start(struct perf_event *event); |
| |
| static int |
| event_sched_in(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| u64 tstamp = perf_event_time(event); |
| int ret = 0; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (event->state <= PERF_EVENT_STATE_OFF) |
| return 0; |
| |
| event->state = PERF_EVENT_STATE_ACTIVE; |
| event->oncpu = smp_processor_id(); |
| |
| /* |
| * Unthrottle events, since we scheduled we might have missed several |
| * ticks already, also for a heavily scheduling task there is little |
| * guarantee it'll get a tick in a timely manner. |
| */ |
| if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { |
| perf_log_throttle(event, 1); |
| event->hw.interrupts = 0; |
| } |
| |
| /* |
| * The new state must be visible before we turn it on in the hardware: |
| */ |
| smp_wmb(); |
| |
| perf_pmu_disable(event->pmu); |
| |
| perf_set_shadow_time(event, ctx, tstamp); |
| |
| perf_log_itrace_start(event); |
| |
| if (event->pmu->add(event, PERF_EF_START)) { |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| event->oncpu = -1; |
| ret = -EAGAIN; |
| goto out; |
| } |
| |
| event->tstamp_running += tstamp - event->tstamp_stopped; |
| |
| if (!is_software_event(event)) |
| cpuctx->active_oncpu++; |
| if (!ctx->nr_active++) |
| perf_event_ctx_activate(ctx); |
| if (event->attr.freq && event->attr.sample_freq) |
| ctx->nr_freq++; |
| |
| if (event->attr.exclusive) |
| cpuctx->exclusive = 1; |
| |
| out: |
| perf_pmu_enable(event->pmu); |
| |
| return ret; |
| } |
| |
| static int |
| group_sched_in(struct perf_event *group_event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *event, *partial_group = NULL; |
| struct pmu *pmu = ctx->pmu; |
| u64 now = ctx->time; |
| bool simulate = false; |
| |
| if (group_event->state == PERF_EVENT_STATE_OFF) |
| return 0; |
| |
| pmu->start_txn(pmu, PERF_PMU_TXN_ADD); |
| |
| if (event_sched_in(group_event, cpuctx, ctx)) { |
| pmu->cancel_txn(pmu); |
| perf_mux_hrtimer_restart(cpuctx); |
| return -EAGAIN; |
| } |
| |
| /* |
| * Schedule in siblings as one group (if any): |
| */ |
| list_for_each_entry(event, &group_event->sibling_list, group_entry) { |
| if (event_sched_in(event, cpuctx, ctx)) { |
| partial_group = event; |
| goto group_error; |
| } |
| } |
| |
| if (!pmu->commit_txn(pmu)) |
| return 0; |
| |
| group_error: |
| /* |
| * Groups can be scheduled in as one unit only, so undo any |
| * partial group before returning: |
| * The events up to the failed event are scheduled out normally, |
| * tstamp_stopped will be updated. |
| * |
| * The failed events and the remaining siblings need to have |
| * their timings updated as if they had gone thru event_sched_in() |
| * and event_sched_out(). This is required to get consistent timings |
| * across the group. This also takes care of the case where the group |
| * could never be scheduled by ensuring tstamp_stopped is set to mark |
| * the time the event was actually stopped, such that time delta |
| * calculation in update_event_times() is correct. |
| */ |
| list_for_each_entry(event, &group_event->sibling_list, group_entry) { |
| if (event == partial_group) |
| simulate = true; |
| |
| if (simulate) { |
| event->tstamp_running += now - event->tstamp_stopped; |
| event->tstamp_stopped = now; |
| } else { |
| event_sched_out(event, cpuctx, ctx); |
| } |
| } |
| event_sched_out(group_event, cpuctx, ctx); |
| |
| pmu->cancel_txn(pmu); |
| |
| perf_mux_hrtimer_restart(cpuctx); |
| |
| return -EAGAIN; |
| } |
| |
| /* |
| * Work out whether we can put this event group on the CPU now. |
| */ |
| static int group_can_go_on(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| int can_add_hw) |
| { |
| /* |
| * Groups consisting entirely of software events can always go on. |
| */ |
| if (event->group_flags & PERF_GROUP_SOFTWARE) |
| return 1; |
| /* |
| * If an exclusive group is already on, no other hardware |
| * events can go on. |
| */ |
| if (cpuctx->exclusive) |
| return 0; |
| /* |
| * If this group is exclusive and there are already |
| * events on the CPU, it can't go on. |
| */ |
| if (event->attr.exclusive && cpuctx->active_oncpu) |
| return 0; |
| /* |
| * Otherwise, try to add it if all previous groups were able |
| * to go on. |
| */ |
| return can_add_hw; |
| } |
| |
| static void add_event_to_ctx(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| u64 tstamp = perf_event_time(event); |
| |
| list_add_event(event, ctx); |
| perf_group_attach(event); |
| event->tstamp_enabled = tstamp; |
| event->tstamp_running = tstamp; |
| event->tstamp_stopped = tstamp; |
| } |
| |
| static void ctx_sched_out(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type); |
| static void |
| ctx_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task); |
| |
| static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx) |
| { |
| if (!cpuctx->task_ctx) |
| return; |
| |
| if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) |
| return; |
| |
| ctx_sched_out(ctx, cpuctx, EVENT_ALL); |
| } |
| |
| static void perf_event_sched_in(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| struct task_struct *task) |
| { |
| cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); |
| if (ctx) |
| ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); |
| cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); |
| if (ctx) |
| ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); |
| } |
| |
| static void ctx_resched(struct perf_cpu_context *cpuctx, |
| struct perf_event_context *task_ctx) |
| { |
| perf_pmu_disable(cpuctx->ctx.pmu); |
| if (task_ctx) |
| task_ctx_sched_out(cpuctx, task_ctx); |
| cpu_ctx_sched_out(cpuctx, EVENT_ALL); |
| perf_event_sched_in(cpuctx, task_ctx, current); |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| } |
| |
| /* |
| * Cross CPU call to install and enable a performance event |
| * |
| * Very similar to remote_function() + event_function() but cannot assume that |
| * things like ctx->is_active and cpuctx->task_ctx are set. |
| */ |
| static int __perf_install_in_context(void *info) |
| { |
| struct perf_event *event = info; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| struct perf_event_context *task_ctx = cpuctx->task_ctx; |
| bool activate = true; |
| int ret = 0; |
| |
| raw_spin_lock(&cpuctx->ctx.lock); |
| if (ctx->task) { |
| raw_spin_lock(&ctx->lock); |
| task_ctx = ctx; |
| |
| /* If we're on the wrong CPU, try again */ |
| if (task_cpu(ctx->task) != smp_processor_id()) { |
| ret = -ESRCH; |
| goto unlock; |
| } |
| |
| /* |
| * If we're on the right CPU, see if the task we target is |
| * current, if not we don't have to activate the ctx, a future |
| * context switch will do that for us. |
| */ |
| if (ctx->task != current) |
| activate = false; |
| else |
| WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx); |
| |
| } else if (task_ctx) { |
| raw_spin_lock(&task_ctx->lock); |
| } |
| |
| if (activate) { |
| ctx_sched_out(ctx, cpuctx, EVENT_TIME); |
| add_event_to_ctx(event, ctx); |
| ctx_resched(cpuctx, task_ctx); |
| } else { |
| add_event_to_ctx(event, ctx); |
| } |
| |
| unlock: |
| perf_ctx_unlock(cpuctx, task_ctx); |
| |
| return ret; |
| } |
| |
| /* |
| * Attach a performance event to a context. |
| * |
| * Very similar to event_function_call, see comment there. |
| */ |
| static void |
| perf_install_in_context(struct perf_event_context *ctx, |
| struct perf_event *event, |
| int cpu) |
| { |
| struct task_struct *task = READ_ONCE(ctx->task); |
| |
| lockdep_assert_held(&ctx->mutex); |
| |
| event->ctx = ctx; |
| if (event->cpu != -1) |
| event->cpu = cpu; |
| |
| if (!task) { |
| cpu_function_call(cpu, __perf_install_in_context, event); |
| return; |
| } |
| |
| /* |
| * Should not happen, we validate the ctx is still alive before calling. |
| */ |
| if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) |
| return; |
| |
| /* |
| * Installing events is tricky because we cannot rely on ctx->is_active |
| * to be set in case this is the nr_events 0 -> 1 transition. |
| */ |
| again: |
| /* |
| * Cannot use task_function_call() because we need to run on the task's |
| * CPU regardless of whether its current or not. |
| */ |
| if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event)) |
| return; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| task = ctx->task; |
| if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { |
| /* |
| * Cannot happen because we already checked above (which also |
| * cannot happen), and we hold ctx->mutex, which serializes us |
| * against perf_event_exit_task_context(). |
| */ |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| raw_spin_unlock_irq(&ctx->lock); |
| /* |
| * Since !ctx->is_active doesn't mean anything, we must IPI |
| * unconditionally. |
| */ |
| goto again; |
| } |
| |
| /* |
| * Put a event into inactive state and update time fields. |
| * Enabling the leader of a group effectively enables all |
| * the group members that aren't explicitly disabled, so we |
| * have to update their ->tstamp_enabled also. |
| * Note: this works for group members as well as group leaders |
| * since the non-leader members' sibling_lists will be empty. |
| */ |
| static void __perf_event_mark_enabled(struct perf_event *event) |
| { |
| struct perf_event *sub; |
| u64 tstamp = perf_event_time(event); |
| |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| event->tstamp_enabled = tstamp - event->total_time_enabled; |
| list_for_each_entry(sub, &event->sibling_list, group_entry) { |
| if (sub->state >= PERF_EVENT_STATE_INACTIVE) |
| sub->tstamp_enabled = tstamp - sub->total_time_enabled; |
| } |
| } |
| |
| /* |
| * Cross CPU call to enable a performance event |
| */ |
| static void __perf_event_enable(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| void *info) |
| { |
| struct perf_event *leader = event->group_leader; |
| struct perf_event_context *task_ctx; |
| |
| if (event->state >= PERF_EVENT_STATE_INACTIVE || |
| event->state <= PERF_EVENT_STATE_ERROR) |
| return; |
| |
| if (ctx->is_active) |
| ctx_sched_out(ctx, cpuctx, EVENT_TIME); |
| |
| __perf_event_mark_enabled(event); |
| |
| if (!ctx->is_active) |
| return; |
| |
| if (!event_filter_match(event)) { |
| if (is_cgroup_event(event)) |
| perf_cgroup_defer_enabled(event); |
| ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); |
| return; |
| } |
| |
| /* |
| * If the event is in a group and isn't the group leader, |
| * then don't put it on unless the group is on. |
| */ |
| if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { |
| ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); |
| return; |
| } |
| |
| task_ctx = cpuctx->task_ctx; |
| if (ctx->task) |
| WARN_ON_ONCE(task_ctx != ctx); |
| |
| ctx_resched(cpuctx, task_ctx); |
| } |
| |
| /* |
| * Enable a event. |
| * |
| * If event->ctx is a cloned context, callers must make sure that |
| * every task struct that event->ctx->task could possibly point to |
| * remains valid. This condition is satisfied when called through |
| * perf_event_for_each_child or perf_event_for_each as described |
| * for perf_event_disable. |
| */ |
| static void _perf_event_enable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| |
| raw_spin_lock_irq(&ctx->lock); |
| if (event->state >= PERF_EVENT_STATE_INACTIVE || |
| event->state < PERF_EVENT_STATE_ERROR) { |
| raw_spin_unlock_irq(&ctx->lock); |
| return; |
| } |
| |
| /* |
| * If the event is in error state, clear that first. |
| * |
| * That way, if we see the event in error state below, we know that it |
| * has gone back into error state, as distinct from the task having |
| * been scheduled away before the cross-call arrived. |
| */ |
| if (event->state == PERF_EVENT_STATE_ERROR) |
| event->state = PERF_EVENT_STATE_OFF; |
| raw_spin_unlock_irq(&ctx->lock); |
| |
| event_function_call(event, __perf_event_enable, NULL); |
| } |
| |
| /* |
| * See perf_event_disable(); |
| */ |
| void perf_event_enable(struct perf_event *event) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = perf_event_ctx_lock(event); |
| _perf_event_enable(event); |
| perf_event_ctx_unlock(event, ctx); |
| } |
| EXPORT_SYMBOL_GPL(perf_event_enable); |
| |
| static int _perf_event_refresh(struct perf_event *event, int refresh) |
| { |
| /* |
| * not supported on inherited events |
| */ |
| if (event->attr.inherit || !is_sampling_event(event)) |
| return -EINVAL; |
| |
| atomic_add(refresh, &event->event_limit); |
| _perf_event_enable(event); |
| |
| return 0; |
| } |
| |
| /* |
| * See perf_event_disable() |
| */ |
| int perf_event_refresh(struct perf_event *event, int refresh) |
| { |
| struct perf_event_context *ctx; |
| int ret; |
| |
| ctx = perf_event_ctx_lock(event); |
| ret = _perf_event_refresh(event, refresh); |
| perf_event_ctx_unlock(event, ctx); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(perf_event_refresh); |
| |
| static void ctx_sched_out(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type) |
| { |
| int is_active = ctx->is_active; |
| struct perf_event *event; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (likely(!ctx->nr_events)) { |
| /* |
| * See __perf_remove_from_context(). |
| */ |
| WARN_ON_ONCE(ctx->is_active); |
| if (ctx->task) |
| WARN_ON_ONCE(cpuctx->task_ctx); |
| return; |
| } |
| |
| ctx->is_active &= ~event_type; |
| if (!(ctx->is_active & EVENT_ALL)) |
| ctx->is_active = 0; |
| |
| if (ctx->task) { |
| WARN_ON_ONCE(cpuctx->task_ctx != ctx); |
| if (!ctx->is_active) |
| cpuctx->task_ctx = NULL; |
| } |
| |
| is_active ^= ctx->is_active; /* changed bits */ |
| |
| if (is_active & EVENT_TIME) { |
| /* update (and stop) ctx time */ |
| update_context_time(ctx); |
| update_cgrp_time_from_cpuctx(cpuctx); |
| } |
| |
| if (!ctx->nr_active || !(is_active & EVENT_ALL)) |
| return; |
| |
| perf_pmu_disable(ctx->pmu); |
| if (is_active & EVENT_PINNED) { |
| list_for_each_entry(event, &ctx->pinned_groups, group_entry) |
| group_sched_out(event, cpuctx, ctx); |
| } |
| |
| if (is_active & EVENT_FLEXIBLE) { |
| list_for_each_entry(event, &ctx->flexible_groups, group_entry) |
| group_sched_out(event, cpuctx, ctx); |
| } |
| perf_pmu_enable(ctx->pmu); |
| } |
| |
| /* |
| * Test whether two contexts are equivalent, i.e. whether they have both been |
| * cloned from the same version of the same context. |
| * |
| * Equivalence is measured using a generation number in the context that is |
| * incremented on each modification to it; see unclone_ctx(), list_add_event() |
| * and list_del_event(). |
| */ |
| static int context_equiv(struct perf_event_context *ctx1, |
| struct perf_event_context *ctx2) |
| { |
| lockdep_assert_held(&ctx1->lock); |
| lockdep_assert_held(&ctx2->lock); |
| |
| /* Pinning disables the swap optimization */ |
| if (ctx1->pin_count || ctx2->pin_count) |
| return 0; |
| |
| /* If ctx1 is the parent of ctx2 */ |
| if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) |
| return 1; |
| |
| /* If ctx2 is the parent of ctx1 */ |
| if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) |
| return 1; |
| |
| /* |
| * If ctx1 and ctx2 have the same parent; we flatten the parent |
| * hierarchy, see perf_event_init_context(). |
| */ |
| if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && |
| ctx1->parent_gen == ctx2->parent_gen) |
| return 1; |
| |
| /* Unmatched */ |
| return 0; |
| } |
| |
| static void __perf_event_sync_stat(struct perf_event *event, |
| struct perf_event *next_event) |
| { |
| u64 value; |
| |
| if (!event->attr.inherit_stat) |
| return; |
| |
| /* |
| * Update the event value, we cannot use perf_event_read() |
| * because we're in the middle of a context switch and have IRQs |
| * disabled, which upsets smp_call_function_single(), however |
| * we know the event must be on the current CPU, therefore we |
| * don't need to use it. |
| */ |
| switch (event->state) { |
| case PERF_EVENT_STATE_ACTIVE: |
| event->pmu->read(event); |
| /* fall-through */ |
| |
| case PERF_EVENT_STATE_INACTIVE: |
| update_event_times(event); |
| break; |
| |
| default: |
| break; |
| } |
| |
| /* |
| * In order to keep per-task stats reliable we need to flip the event |
| * values when we flip the contexts. |
| */ |
| value = local64_read(&next_event->count); |
| value = local64_xchg(&event->count, value); |
| local64_set(&next_event->count, value); |
| |
| swap(event->total_time_enabled, next_event->total_time_enabled); |
| swap(event->total_time_running, next_event->total_time_running); |
| |
| /* |
| * Since we swizzled the values, update the user visible data too. |
| */ |
| perf_event_update_userpage(event); |
| perf_event_update_userpage(next_event); |
| } |
| |
| static void perf_event_sync_stat(struct perf_event_context *ctx, |
| struct perf_event_context *next_ctx) |
| { |
| struct perf_event *event, *next_event; |
| |
| if (!ctx->nr_stat) |
| return; |
| |
| update_context_time(ctx); |
| |
| event = list_first_entry(&ctx->event_list, |
| struct perf_event, event_entry); |
| |
| next_event = list_first_entry(&next_ctx->event_list, |
| struct perf_event, event_entry); |
| |
| while (&event->event_entry != &ctx->event_list && |
| &next_event->event_entry != &next_ctx->event_list) { |
| |
| __perf_event_sync_stat(event, next_event); |
| |
| event = list_next_entry(event, event_entry); |
| next_event = list_next_entry(next_event, event_entry); |
| } |
| } |
| |
| static void perf_event_context_sched_out(struct task_struct *task, int ctxn, |
| struct task_struct *next) |
| { |
| struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; |
| struct perf_event_context *next_ctx; |
| struct perf_event_context *parent, *next_parent; |
| struct perf_cpu_context *cpuctx; |
| int do_switch = 1; |
| |
| if (likely(!ctx)) |
| return; |
| |
| cpuctx = __get_cpu_context(ctx); |
| if (!cpuctx->task_ctx) |
| return; |
| |
| rcu_read_lock(); |
| next_ctx = next->perf_event_ctxp[ctxn]; |
| if (!next_ctx) |
| goto unlock; |
| |
| parent = rcu_dereference(ctx->parent_ctx); |
| next_parent = rcu_dereference(next_ctx->parent_ctx); |
| |
| /* If neither context have a parent context; they cannot be clones. */ |
| if (!parent && !next_parent) |
| goto unlock; |
| |
| if (next_parent == ctx || next_ctx == parent || next_parent == parent) { |
| /* |
| * Looks like the two contexts are clones, so we might be |
| * able to optimize the context switch. We lock both |
| * contexts and check that they are clones under the |
| * lock (including re-checking that neither has been |
| * uncloned in the meantime). It doesn't matter which |
| * order we take the locks because no other cpu could |
| * be trying to lock both of these tasks. |
| */ |
| raw_spin_lock(&ctx->lock); |
| raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); |
| if (context_equiv(ctx, next_ctx)) { |
| WRITE_ONCE(ctx->task, next); |
| WRITE_ONCE(next_ctx->task, task); |
| |
| swap(ctx->task_ctx_data, next_ctx->task_ctx_data); |
| |
| /* |
| * RCU_INIT_POINTER here is safe because we've not |
| * modified the ctx and the above modification of |
| * ctx->task and ctx->task_ctx_data are immaterial |
| * since those values are always verified under |
| * ctx->lock which we're now holding. |
| */ |
| RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); |
| RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); |
| |
| do_switch = 0; |
| |
| perf_event_sync_stat(ctx, next_ctx); |
| } |
| raw_spin_unlock(&next_ctx->lock); |
| raw_spin_unlock(&ctx->lock); |
| } |
| unlock: |
| rcu_read_unlock(); |
| |
| if (do_switch) { |
| raw_spin_lock(&ctx->lock); |
| task_ctx_sched_out(cpuctx, ctx); |
| raw_spin_unlock(&ctx->lock); |
| } |
| } |
| |
| void perf_sched_cb_dec(struct pmu *pmu) |
| { |
| this_cpu_dec(perf_sched_cb_usages); |
| } |
| |
| void perf_sched_cb_inc(struct pmu *pmu) |
| { |
| this_cpu_inc(perf_sched_cb_usages); |
| } |
| |
| /* |
| * This function provides the context switch callback to the lower code |
| * layer. It is invoked ONLY when the context switch callback is enabled. |
| */ |
| static void perf_pmu_sched_task(struct task_struct *prev, |
| struct task_struct *next, |
| bool sched_in) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct pmu *pmu; |
| unsigned long flags; |
| |
| if (prev == next) |
| return; |
| |
| local_irq_save(flags); |
| |
| rcu_read_lock(); |
| |
| list_for_each_entry_rcu(pmu, &pmus, entry) { |
| if (pmu->sched_task) { |
| cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); |
| |
| perf_ctx_lock(cpuctx, cpuctx->task_ctx); |
| |
| perf_pmu_disable(pmu); |
| |
| pmu->sched_task(cpuctx->task_ctx, sched_in); |
| |
| perf_pmu_enable(pmu); |
| |
| perf_ctx_unlock(cpuctx, cpuctx->task_ctx); |
| } |
| } |
| |
| rcu_read_unlock(); |
| |
| local_irq_restore(flags); |
| } |
| |
| static void perf_event_switch(struct task_struct *task, |
| struct task_struct *next_prev, bool sched_in); |
| |
| #define for_each_task_context_nr(ctxn) \ |
| for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) |
| |
| /* |
| * Called from scheduler to remove the events of the current task, |
| * with interrupts disabled. |
| * |
| * We stop each event and update the event value in event->count. |
| * |
| * This does not protect us against NMI, but disable() |
| * sets the disabled bit in the control field of event _before_ |
| * accessing the event control register. If a NMI hits, then it will |
| * not restart the event. |
| */ |
| void __perf_event_task_sched_out(struct task_struct *task, |
| struct task_struct *next) |
| { |
| int ctxn; |
| |
| if (__this_cpu_read(perf_sched_cb_usages)) |
| perf_pmu_sched_task(task, next, false); |
| |
| if (atomic_read(&nr_switch_events)) |
| perf_event_switch(task, next, false); |
| |
| for_each_task_context_nr(ctxn) |
| perf_event_context_sched_out(task, ctxn, next); |
| |
| /* |
| * if cgroup events exist on this CPU, then we need |
| * to check if we have to switch out PMU state. |
| * cgroup event are system-wide mode only |
| */ |
| if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) |
| perf_cgroup_sched_out(task, next); |
| } |
| |
| /* |
| * Called with IRQs disabled |
| */ |
| static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type) |
| { |
| ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); |
| } |
| |
| static void |
| ctx_pinned_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx) |
| { |
| struct perf_event *event; |
| |
| list_for_each_entry(event, &ctx->pinned_groups, group_entry) { |
| if (event->state <= PERF_EVENT_STATE_OFF) |
| continue; |
| if (!event_filter_match(event)) |
| continue; |
| |
| /* may need to reset tstamp_enabled */ |
| if (is_cgroup_event(event)) |
| perf_cgroup_mark_enabled(event, ctx); |
| |
| if (group_can_go_on(event, cpuctx, 1)) |
| group_sched_in(event, cpuctx, ctx); |
| |
| /* |
| * If this pinned group hasn't been scheduled, |
| * put it in error state. |
| */ |
| if (event->state == PERF_EVENT_STATE_INACTIVE) { |
| update_group_times(event); |
| event->state = PERF_EVENT_STATE_ERROR; |
| } |
| } |
| } |
| |
| static void |
| ctx_flexible_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx) |
| { |
| struct perf_event *event; |
| int can_add_hw = 1; |
| |
| list_for_each_entry(event, &ctx->flexible_groups, group_entry) { |
| /* Ignore events in OFF or ERROR state */ |
| if (event->state <= PERF_EVENT_STATE_OFF) |
| continue; |
| /* |
| * Listen to the 'cpu' scheduling filter constraint |
| * of events: |
| */ |
| if (!event_filter_match(event)) |
| continue; |
| |
| /* may need to reset tstamp_enabled */ |
| if (is_cgroup_event(event)) |
| perf_cgroup_mark_enabled(event, ctx); |
| |
| if (group_can_go_on(event, cpuctx, can_add_hw)) { |
| if (group_sched_in(event, cpuctx, ctx)) |
| can_add_hw = 0; |
| } |
| } |
| } |
| |
| static void |
| ctx_sched_in(struct perf_event_context *ctx, |
| struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task) |
| { |
| int is_active = ctx->is_active; |
| u64 now; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| if (likely(!ctx->nr_events)) |
| return; |
| |
| ctx->is_active |= (event_type | EVENT_TIME); |
| if (ctx->task) { |
| if (!is_active) |
| cpuctx->task_ctx = ctx; |
| else |
| WARN_ON_ONCE(cpuctx->task_ctx != ctx); |
| } |
| |
| is_active ^= ctx->is_active; /* changed bits */ |
| |
| if (is_active & EVENT_TIME) { |
| /* start ctx time */ |
| now = perf_clock(); |
| ctx->timestamp = now; |
| perf_cgroup_set_timestamp(task, ctx); |
| } |
| |
| /* |
| * First go through the list and put on any pinned groups |
| * in order to give them the best chance of going on. |
| */ |
| if (is_active & EVENT_PINNED) |
| ctx_pinned_sched_in(ctx, cpuctx); |
| |
| /* Then walk through the lower prio flexible groups */ |
| if (is_active & EVENT_FLEXIBLE) |
| ctx_flexible_sched_in(ctx, cpuctx); |
| } |
| |
| static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, |
| enum event_type_t event_type, |
| struct task_struct *task) |
| { |
| struct perf_event_context *ctx = &cpuctx->ctx; |
| |
| ctx_sched_in(ctx, cpuctx, event_type, task); |
| } |
| |
| static void perf_event_context_sched_in(struct perf_event_context *ctx, |
| struct task_struct *task) |
| { |
| struct perf_cpu_context *cpuctx; |
| |
| cpuctx = __get_cpu_context(ctx); |
| if (cpuctx->task_ctx == ctx) |
| return; |
| |
| perf_ctx_lock(cpuctx, ctx); |
| perf_pmu_disable(ctx->pmu); |
| /* |
| * We want to keep the following priority order: |
| * cpu pinned (that don't need to move), task pinned, |
| * cpu flexible, task flexible. |
| */ |
| cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
| perf_event_sched_in(cpuctx, ctx, task); |
| perf_pmu_enable(ctx->pmu); |
| perf_ctx_unlock(cpuctx, ctx); |
| } |
| |
| /* |
| * Called from scheduler to add the events of the current task |
| * with interrupts disabled. |
| * |
| * We restore the event value and then enable it. |
| * |
| * This does not protect us against NMI, but enable() |
| * sets the enabled bit in the control field of event _before_ |
| * accessing the event control register. If a NMI hits, then it will |
| * keep the event running. |
| */ |
| void __perf_event_task_sched_in(struct task_struct *prev, |
| struct task_struct *task) |
| { |
| struct perf_event_context *ctx; |
| int ctxn; |
| |
| /* |
| * If cgroup events exist on this CPU, then we need to check if we have |
| * to switch in PMU state; cgroup event are system-wide mode only. |
| * |
| * Since cgroup events are CPU events, we must schedule these in before |
| * we schedule in the task events. |
| */ |
| if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) |
| perf_cgroup_sched_in(prev, task); |
| |
| for_each_task_context_nr(ctxn) { |
| ctx = task->perf_event_ctxp[ctxn]; |
| if (likely(!ctx)) |
| continue; |
| |
| perf_event_context_sched_in(ctx, task); |
| } |
| |
| if (atomic_read(&nr_switch_events)) |
| perf_event_switch(task, prev, true); |
| |
| if (__this_cpu_read(perf_sched_cb_usages)) |
| perf_pmu_sched_task(prev, task, true); |
| } |
| |
| static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) |
| { |
| u64 frequency = event->attr.sample_freq; |
| u64 sec = NSEC_PER_SEC; |
| u64 divisor, dividend; |
| |
| int count_fls, nsec_fls, frequency_fls, sec_fls; |
| |
| count_fls = fls64(count); |
| nsec_fls = fls64(nsec); |
| frequency_fls = fls64(frequency); |
| sec_fls = 30; |
| |
| /* |
| * We got @count in @nsec, with a target of sample_freq HZ |
| * the target period becomes: |
| * |
| * @count * 10^9 |
| * period = ------------------- |
| * @nsec * sample_freq |
| * |
| */ |
| |
| /* |
| * Reduce accuracy by one bit such that @a and @b converge |
| * to a similar magnitude. |
| */ |
| #define REDUCE_FLS(a, b) \ |
| do { \ |
| if (a##_fls > b##_fls) { \ |
| a >>= 1; \ |
| a##_fls--; \ |
| } else { \ |
| b >>= 1; \ |
| b##_fls--; \ |
| } \ |
| } while (0) |
| |
| /* |
| * Reduce accuracy until either term fits in a u64, then proceed with |
| * the other, so that finally we can do a u64/u64 division. |
| */ |
| while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { |
| REDUCE_FLS(nsec, frequency); |
| REDUCE_FLS(sec, count); |
| } |
| |
| if (count_fls + sec_fls > 64) { |
| divisor = nsec * frequency; |
| |
| while (count_fls + sec_fls > 64) { |
| REDUCE_FLS(count, sec); |
| divisor >>= 1; |
| } |
| |
| dividend = count * sec; |
| } else { |
| dividend = count * sec; |
| |
| while (nsec_fls + frequency_fls > 64) { |
| REDUCE_FLS(nsec, frequency); |
| dividend >>= 1; |
| } |
| |
| divisor = nsec * frequency; |
| } |
| |
| if (!divisor) |
| return dividend; |
| |
| return div64_u64(dividend, divisor); |
| } |
| |
| static DEFINE_PER_CPU(int, perf_throttled_count); |
| static DEFINE_PER_CPU(u64, perf_throttled_seq); |
| |
| static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| s64 period, sample_period; |
| s64 delta; |
| |
| period = perf_calculate_period(event, nsec, count); |
| |
| delta = (s64)(period - hwc->sample_period); |
| delta = (delta + 7) / 8; /* low pass filter */ |
| |
| sample_period = hwc->sample_period + delta; |
| |
| if (!sample_period) |
| sample_period = 1; |
| |
| hwc->sample_period = sample_period; |
| |
| if (local64_read(&hwc->period_left) > 8*sample_period) { |
| if (disable) |
| event->pmu->stop(event, PERF_EF_UPDATE); |
| |
| local64_set(&hwc->period_left, 0); |
| |
| if (disable) |
| event->pmu->start(event, PERF_EF_RELOAD); |
| } |
| } |
| |
| /* |
| * combine freq adjustment with unthrottling to avoid two passes over the |
| * events. At the same time, make sure, having freq events does not change |
| * the rate of unthrottling as that would introduce bias. |
| */ |
| static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, |
| int needs_unthr) |
| { |
| struct perf_event *event; |
| struct hw_perf_event *hwc; |
| u64 now, period = TICK_NSEC; |
| s64 delta; |
| |
| /* |
| * only need to iterate over all events iff: |
| * - context have events in frequency mode (needs freq adjust) |
| * - there are events to unthrottle on this cpu |
| */ |
| if (!(ctx->nr_freq || needs_unthr)) |
| return; |
| |
| raw_spin_lock(&ctx->lock); |
| perf_pmu_disable(ctx->pmu); |
| |
| list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
| if (event->state != PERF_EVENT_STATE_ACTIVE) |
| continue; |
| |
| if (!event_filter_match(event)) |
| continue; |
| |
| perf_pmu_disable(event->pmu); |
| |
| hwc = &event->hw; |
| |
| if (hwc->interrupts == MAX_INTERRUPTS) { |
| hwc->interrupts = 0; |
| perf_log_throttle(event, 1); |
| event->pmu->start(event, 0); |
| } |
| |
| if (!event->attr.freq || !event->attr.sample_freq) |
| goto next; |
| |
| /* |
| * stop the event and update event->count |
| */ |
| event->pmu->stop(event, PERF_EF_UPDATE); |
| |
| now = local64_read(&event->count); |
| delta = now - hwc->freq_count_stamp; |
| hwc->freq_count_stamp = now; |
| |
| /* |
| * restart the event |
| * reload only if value has changed |
| * we have stopped the event so tell that |
| * to perf_adjust_period() to avoid stopping it |
| * twice. |
| */ |
| if (delta > 0) |
| perf_adjust_period(event, period, delta, false); |
| |
| event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); |
| next: |
| perf_pmu_enable(event->pmu); |
| } |
| |
| perf_pmu_enable(ctx->pmu); |
| raw_spin_unlock(&ctx->lock); |
| } |
| |
| /* |
| * Round-robin a context's events: |
| */ |
| static void rotate_ctx(struct perf_event_context *ctx) |
| { |
| /* |
| * Rotate the first entry last of non-pinned groups. Rotation might be |
| * disabled by the inheritance code. |
| */ |
| if (!ctx->rotate_disable) |
| list_rotate_left(&ctx->flexible_groups); |
| } |
| |
| static int perf_rotate_context(struct perf_cpu_context *cpuctx) |
| { |
| struct perf_event_context *ctx = NULL; |
| int rotate = 0; |
| |
| if (cpuctx->ctx.nr_events) { |
| if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) |
| rotate = 1; |
| } |
| |
| ctx = cpuctx->task_ctx; |
| if (ctx && ctx->nr_events) { |
| if (ctx->nr_events != ctx->nr_active) |
| rotate = 1; |
| } |
| |
| if (!rotate) |
| goto done; |
| |
| perf_ctx_lock(cpuctx, cpuctx->task_ctx); |
| perf_pmu_disable(cpuctx->ctx.pmu); |
| |
| cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
| if (ctx) |
| ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); |
| |
| rotate_ctx(&cpuctx->ctx); |
| if (ctx) |
| rotate_ctx(ctx); |
| |
| perf_event_sched_in(cpuctx, ctx, current); |
| |
| perf_pmu_enable(cpuctx->ctx.pmu); |
| perf_ctx_unlock(cpuctx, cpuctx->task_ctx); |
| done: |
| |
| return rotate; |
| } |
| |
| void perf_event_task_tick(void) |
| { |
| struct list_head *head = this_cpu_ptr(&active_ctx_list); |
| struct perf_event_context *ctx, *tmp; |
| int throttled; |
| |
| WARN_ON(!irqs_disabled()); |
| |
| __this_cpu_inc(perf_throttled_seq); |
| throttled = __this_cpu_xchg(perf_throttled_count, 0); |
| tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); |
| |
| list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) |
| perf_adjust_freq_unthr_context(ctx, throttled); |
| } |
| |
| static int event_enable_on_exec(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| if (!event->attr.enable_on_exec) |
| return 0; |
| |
| event->attr.enable_on_exec = 0; |
| if (event->state >= PERF_EVENT_STATE_INACTIVE) |
| return 0; |
| |
| __perf_event_mark_enabled(event); |
| |
| return 1; |
| } |
| |
| /* |
| * Enable all of a task's events that have been marked enable-on-exec. |
| * This expects task == current. |
| */ |
| static void perf_event_enable_on_exec(int ctxn) |
| { |
| struct perf_event_context *ctx, *clone_ctx = NULL; |
| struct perf_cpu_context *cpuctx; |
| struct perf_event *event; |
| unsigned long flags; |
| int enabled = 0; |
| |
| local_irq_save(flags); |
| ctx = current->perf_event_ctxp[ctxn]; |
| if (!ctx || !ctx->nr_events) |
| goto out; |
| |
| cpuctx = __get_cpu_context(ctx); |
| perf_ctx_lock(cpuctx, ctx); |
| ctx_sched_out(ctx, cpuctx, EVENT_TIME); |
| list_for_each_entry(event, &ctx->event_list, event_entry) |
| enabled |= event_enable_on_exec(event, ctx); |
| |
| /* |
| * Unclone and reschedule this context if we enabled any event. |
| */ |
| if (enabled) { |
| clone_ctx = unclone_ctx(ctx); |
| ctx_resched(cpuctx, ctx); |
| } |
| perf_ctx_unlock(cpuctx, ctx); |
| |
| out: |
| local_irq_restore(flags); |
| |
| if (clone_ctx) |
| put_ctx(clone_ctx); |
| } |
| |
| void perf_event_exec(void) |
| { |
| int ctxn; |
| |
| rcu_read_lock(); |
| for_each_task_context_nr(ctxn) |
| perf_event_enable_on_exec(ctxn); |
| rcu_read_unlock(); |
| } |
| |
| struct perf_read_data { |
| struct perf_event *event; |
| bool group; |
| int ret; |
| }; |
| |
| /* |
| * Cross CPU call to read the hardware event |
| */ |
| static void __perf_event_read(void *info) |
| { |
| struct perf_read_data *data = info; |
| struct perf_event *sub, *event = data->event; |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| struct pmu *pmu = event->pmu; |
| |
| /* |
| * If this is a task context, we need to check whether it is |
| * the current task context of this cpu. If not it has been |
| * scheduled out before the smp call arrived. In that case |
| * event->count would have been updated to a recent sample |
| * when the event was scheduled out. |
| */ |
| if (ctx->task && cpuctx->task_ctx != ctx) |
| return; |
| |
| raw_spin_lock(&ctx->lock); |
| if (ctx->is_active) { |
| update_context_time(ctx); |
| update_cgrp_time_from_event(event); |
| } |
| |
| update_event_times(event); |
| if (event->state != PERF_EVENT_STATE_ACTIVE) |
| goto unlock; |
| |
| if (!data->group) { |
| pmu->read(event); |
| data->ret = 0; |
| goto unlock; |
| } |
| |
| pmu->start_txn(pmu, PERF_PMU_TXN_READ); |
| |
| pmu->read(event); |
| |
| list_for_each_entry(sub, &event->sibling_list, group_entry) { |
| update_event_times(sub); |
| if (sub->state == PERF_EVENT_STATE_ACTIVE) { |
| /* |
| * Use sibling's PMU rather than @event's since |
| * sibling could be on different (eg: software) PMU. |
| */ |
| sub->pmu->read(sub); |
| } |
| } |
| |
| data->ret = pmu->commit_txn(pmu); |
| |
| unlock: |
| raw_spin_unlock(&ctx->lock); |
| } |
| |
| static inline u64 perf_event_count(struct perf_event *event) |
| { |
| if (event->pmu->count) |
| return event->pmu->count(event); |
| |
| return __perf_event_count(event); |
| } |
| |
| /* |
| * NMI-safe method to read a local event, that is an event that |
| * is: |
| * - either for the current task, or for this CPU |
| * - does not have inherit set, for inherited task events |
| * will not be local and we cannot read them atomically |
| * - must not have a pmu::count method |
| */ |
| u64 perf_event_read_local(struct perf_event *event) |
| { |
| unsigned long flags; |
| u64 val; |
| |
| /* |
| * Disabling interrupts avoids all counter scheduling (context |
| * switches, timer based rotation and IPIs). |
| */ |
| local_irq_save(flags); |
| |
| /* If this is a per-task event, it must be for current */ |
| WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) && |
| event->hw.target != current); |
| |
| /* If this is a per-CPU event, it must be for this CPU */ |
| WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) && |
| event->cpu != smp_processor_id()); |
| |
| /* |
| * It must not be an event with inherit set, we cannot read |
| * all child counters from atomic context. |
| */ |
| WARN_ON_ONCE(event->attr.inherit); |
| |
| /* |
| * It must not have a pmu::count method, those are not |
| * NMI safe. |
| */ |
| WARN_ON_ONCE(event->pmu->count); |
| |
| /* |
| * If the event is currently on this CPU, its either a per-task event, |
| * or local to this CPU. Furthermore it means its ACTIVE (otherwise |
| * oncpu == -1). |
| */ |
| if (event->oncpu == smp_processor_id()) |
| event->pmu->read(event); |
| |
| val = local64_read(&event->count); |
| local_irq_restore(flags); |
| |
| return val; |
| } |
| |
| static int perf_event_read(struct perf_event *event, bool group) |
| { |
| int ret = 0; |
| |
| /* |
| * If event is enabled and currently active on a CPU, update the |
| * value in the event structure: |
| */ |
| if (event->state == PERF_EVENT_STATE_ACTIVE) { |
| struct perf_read_data data = { |
| .event = event, |
| .group = group, |
| .ret = 0, |
| }; |
| smp_call_function_single(event->oncpu, |
| __perf_event_read, &data, 1); |
| ret = data.ret; |
| } else if (event->state == PERF_EVENT_STATE_INACTIVE) { |
| struct perf_event_context *ctx = event->ctx; |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&ctx->lock, flags); |
| /* |
| * may read while context is not active |
| * (e.g., thread is blocked), in that case |
| * we cannot update context time |
| */ |
| if (ctx->is_active) { |
| update_context_time(ctx); |
| update_cgrp_time_from_event(event); |
| } |
| if (group) |
| update_group_times(event); |
| else |
| update_event_times(event); |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Initialize the perf_event context in a task_struct: |
| */ |
| static void __perf_event_init_context(struct perf_event_context *ctx) |
| { |
| raw_spin_lock_init(&ctx->lock); |
| mutex_init(&ctx->mutex); |
| INIT_LIST_HEAD(&ctx->active_ctx_list); |
| INIT_LIST_HEAD(&ctx->pinned_groups); |
| INIT_LIST_HEAD(&ctx->flexible_groups); |
| INIT_LIST_HEAD(&ctx->event_list); |
| atomic_set(&ctx->refcount, 1); |
| } |
| |
| static struct perf_event_context * |
| alloc_perf_context(struct pmu *pmu, struct task_struct *task) |
| { |
| struct perf_event_context *ctx; |
| |
| ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); |
| if (!ctx) |
| return NULL; |
| |
| __perf_event_init_context(ctx); |
| if (task) { |
| ctx->task = task; |
| get_task_struct(task); |
| } |
| ctx->pmu = pmu; |
| |
| return ctx; |
| } |
| |
| static struct task_struct * |
| find_lively_task_by_vpid(pid_t vpid) |
| { |
| struct task_struct *task; |
| int err; |
| |
| rcu_read_lock(); |
| if (!vpid) |
| task = current; |
| else |
| task = find_task_by_vpid(vpid); |
| if (task) |
| get_task_struct(task); |
| rcu_read_unlock(); |
| |
| if (!task) |
| return ERR_PTR(-ESRCH); |
| |
| /* Reuse ptrace permission checks for now. */ |
| err = -EACCES; |
| if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) |
| goto errout; |
| |
| return task; |
| errout: |
| put_task_struct(task); |
| return ERR_PTR(err); |
| |
| } |
| |
| /* |
| * Returns a matching context with refcount and pincount. |
| */ |
| static struct perf_event_context * |
| find_get_context(struct pmu *pmu, struct task_struct *task, |
| struct perf_event *event) |
| { |
| struct perf_event_context *ctx, *clone_ctx = NULL; |
| struct perf_cpu_context *cpuctx; |
| void *task_ctx_data = NULL; |
| unsigned long flags; |
| int ctxn, err; |
| int cpu = event->cpu; |
| |
| if (!task) { |
| /* Must be root to operate on a CPU event: */ |
| if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) |
| return ERR_PTR(-EACCES); |
| |
| /* |
| * We could be clever and allow to attach a event to an |
| * offline CPU and activate it when the CPU comes up, but |
| * that's for later. |
| */ |
| if (!cpu_online(cpu)) |
| return ERR_PTR(-ENODEV); |
| |
| cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); |
| ctx = &cpuctx->ctx; |
| get_ctx(ctx); |
| ++ctx->pin_count; |
| |
| return ctx; |
| } |
| |
| err = -EINVAL; |
| ctxn = pmu->task_ctx_nr; |
| if (ctxn < 0) |
| goto errout; |
| |
| if (event->attach_state & PERF_ATTACH_TASK_DATA) { |
| task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL); |
| if (!task_ctx_data) { |
| err = -ENOMEM; |
| goto errout; |
| } |
| } |
| |
| retry: |
| ctx = perf_lock_task_context(task, ctxn, &flags); |
| if (ctx) { |
| clone_ctx = unclone_ctx(ctx); |
| ++ctx->pin_count; |
| |
| if (task_ctx_data && !ctx->task_ctx_data) { |
| ctx->task_ctx_data = task_ctx_data; |
| task_ctx_data = NULL; |
| } |
| raw_spin_unlock_irqrestore(&ctx->lock, flags); |
| |
| if (clone_ctx) |
| put_ctx(clone_ctx); |
| } else { |
| ctx = alloc_perf_context(pmu, task); |
| err = -ENOMEM; |
| if (!ctx) |
| goto errout; |
| |
| if (task_ctx_data) { |
| ctx->task_ctx_data = task_ctx_data; |
| task_ctx_data = NULL; |
| } |
| |
| err = 0; |
| mutex_lock(&task->perf_event_mutex); |
| /* |
| * If it has already passed perf_event_exit_task(). |
| * we must see PF_EXITING, it takes this mutex too. |
| */ |
| if (task->flags & PF_EXITING) |
| err = -ESRCH; |
| else if (task->perf_event_ctxp[ctxn]) |
| err = -EAGAIN; |
| else { |
| get_ctx(ctx); |
| ++ctx->pin_count; |
| rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); |
| } |
| mutex_unlock(&task->perf_event_mutex); |
| |
| if (unlikely(err)) { |
| put_ctx(ctx); |
| |
| if (err == -EAGAIN) |
| goto retry; |
| goto errout; |
| } |
| } |
| |
| kfree(task_ctx_data); |
| return ctx; |
| |
| errout: |
| kfree(task_ctx_data); |
| return ERR_PTR(err); |
| } |
| |
| static void perf_event_free_filter(struct perf_event *event); |
| static void perf_event_free_bpf_prog(struct perf_event *event); |
| |
| static void free_event_rcu(struct rcu_head *head) |
| { |
| struct perf_event *event; |
| |
| event = container_of(head, struct perf_event, rcu_head); |
| if (event->ns) |
| put_pid_ns(event->ns); |
| perf_event_free_filter(event); |
| kfree(event); |
| } |
| |
| static void ring_buffer_attach(struct perf_event *event, |
| struct ring_buffer *rb); |
| |
| static void unaccount_event_cpu(struct perf_event *event, int cpu) |
| { |
| if (event->parent) |
| return; |
| |
| if (is_cgroup_event(event)) |
| atomic_dec(&per_cpu(perf_cgroup_events, cpu)); |
| } |
| |
| #ifdef CONFIG_NO_HZ_FULL |
| static DEFINE_SPINLOCK(nr_freq_lock); |
| #endif |
| |
| static void unaccount_freq_event_nohz(void) |
| { |
| #ifdef CONFIG_NO_HZ_FULL |
| spin_lock(&nr_freq_lock); |
| if (atomic_dec_and_test(&nr_freq_events)) |
| tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); |
| spin_unlock(&nr_freq_lock); |
| #endif |
| } |
| |
| static void unaccount_freq_event(void) |
| { |
| if (tick_nohz_full_enabled()) |
| unaccount_freq_event_nohz(); |
| else |
| atomic_dec(&nr_freq_events); |
| } |
| |
| static void unaccount_event(struct perf_event *event) |
| { |
| bool dec = false; |
| |
| if (event->parent) |
| return; |
| |
| if (event->attach_state & PERF_ATTACH_TASK) |
| dec = true; |
| if (event->attr.mmap || event->attr.mmap_data) |
| atomic_dec(&nr_mmap_events); |
| if (event->attr.comm) |
| atomic_dec(&nr_comm_events); |
| if (event->attr.task) |
| atomic_dec(&nr_task_events); |
| if (event->attr.freq) |
| unaccount_freq_event(); |
| if (event->attr.context_switch) { |
| dec = true; |
| atomic_dec(&nr_switch_events); |
| } |
| if (is_cgroup_event(event)) |
| dec = true; |
| if (has_branch_stack(event)) |
| dec = true; |
| |
| if (dec) { |
| if (!atomic_add_unless(&perf_sched_count, -1, 1)) |
| schedule_delayed_work(&perf_sched_work, HZ); |
| } |
| |
| unaccount_event_cpu(event, event->cpu); |
| } |
| |
| static void perf_sched_delayed(struct work_struct *work) |
| { |
| mutex_lock(&perf_sched_mutex); |
| if (atomic_dec_and_test(&perf_sched_count)) |
| static_branch_disable(&perf_sched_events); |
| mutex_unlock(&perf_sched_mutex); |
| } |
| |
| /* |
| * The following implement mutual exclusion of events on "exclusive" pmus |
| * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled |
| * at a time, so we disallow creating events that might conflict, namely: |
| * |
| * 1) cpu-wide events in the presence of per-task events, |
| * 2) per-task events in the presence of cpu-wide events, |
| * 3) two matching events on the same context. |
| * |
| * The former two cases are handled in the allocation path (perf_event_alloc(), |
| * _free_event()), the latter -- before the first perf_install_in_context(). |
| */ |
| static int exclusive_event_init(struct perf_event *event) |
| { |
| struct pmu *pmu = event->pmu; |
| |
| if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) |
| return 0; |
| |
| /* |
| * Prevent co-existence of per-task and cpu-wide events on the |
| * same exclusive pmu. |
| * |
| * Negative pmu::exclusive_cnt means there are cpu-wide |
| * events on this "exclusive" pmu, positive means there are |
| * per-task events. |
| * |
| * Since this is called in perf_event_alloc() path, event::ctx |
| * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK |
| * to mean "per-task event", because unlike other attach states it |
| * never gets cleared. |
| */ |
| if (event->attach_state & PERF_ATTACH_TASK) { |
| if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) |
| return -EBUSY; |
| } else { |
| if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) |
| return -EBUSY; |
| } |
| |
| return 0; |
| } |
| |
| static void exclusive_event_destroy(struct perf_event *event) |
| { |
| struct pmu *pmu = event->pmu; |
| |
| if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) |
| return; |
| |
| /* see comment in exclusive_event_init() */ |
| if (event->attach_state & PERF_ATTACH_TASK) |
| atomic_dec(&pmu->exclusive_cnt); |
| else |
| atomic_inc(&pmu->exclusive_cnt); |
| } |
| |
| static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) |
| { |
| if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && |
| (e1->cpu == e2->cpu || |
| e1->cpu == -1 || |
| e2->cpu == -1)) |
| return true; |
| return false; |
| } |
| |
| /* Called under the same ctx::mutex as perf_install_in_context() */ |
| static bool exclusive_event_installable(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *iter_event; |
| struct pmu *pmu = event->pmu; |
| |
| if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) |
| return true; |
| |
| list_for_each_entry(iter_event, &ctx->event_list, event_entry) { |
| if (exclusive_event_match(iter_event, event)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| static void _free_event(struct perf_event *event) |
| { |
| irq_work_sync(&event->pending); |
| |
| unaccount_event(event); |
| |
| if (event->rb) { |
| /* |
| * Can happen when we close an event with re-directed output. |
| * |
| * Since we have a 0 refcount, perf_mmap_close() will skip |
| * over us; possibly making our ring_buffer_put() the last. |
| */ |
| mutex_lock(&event->mmap_mutex); |
| ring_buffer_attach(event, NULL); |
| mutex_unlock(&event->mmap_mutex); |
| } |
| |
| if (is_cgroup_event(event)) |
| perf_detach_cgroup(event); |
| |
| if (!event->parent) { |
| if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) |
| put_callchain_buffers(); |
| } |
| |
| perf_event_free_bpf_prog(event); |
| |
| if (event->destroy) |
| event->destroy(event); |
| |
| if (event->ctx) |
| put_ctx(event->ctx); |
| |
| if (event->pmu) { |
| exclusive_event_destroy(event); |
| module_put(event->pmu->module); |
| } |
| |
| call_rcu(&event->rcu_head, free_event_rcu); |
| } |
| |
| /* |
| * Used to free events which have a known refcount of 1, such as in error paths |
| * where the event isn't exposed yet and inherited events. |
| */ |
| static void free_event(struct perf_event *event) |
| { |
| if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, |
| "unexpected event refcount: %ld; ptr=%p\n", |
| atomic_long_read(&event->refcount), event)) { |
| /* leak to avoid use-after-free */ |
| return; |
| } |
| |
| _free_event(event); |
| } |
| |
| /* |
| * Remove user event from the owner task. |
| */ |
| static void perf_remove_from_owner(struct perf_event *event) |
| { |
| struct task_struct *owner; |
| |
| rcu_read_lock(); |
| /* |
| * Matches the smp_store_release() in perf_event_exit_task(). If we |
| * observe !owner it means the list deletion is complete and we can |
| * indeed free this event, otherwise we need to serialize on |
| * owner->perf_event_mutex. |
| */ |
| owner = lockless_dereference(event->owner); |
| if (owner) { |
| /* |
| * Since delayed_put_task_struct() also drops the last |
| * task reference we can safely take a new reference |
| * while holding the rcu_read_lock(). |
| */ |
| get_task_struct(owner); |
| } |
| rcu_read_unlock(); |
| |
| if (owner) { |
| /* |
| * If we're here through perf_event_exit_task() we're already |
| * holding ctx->mutex which would be an inversion wrt. the |
| * normal lock order. |
| * |
| * However we can safely take this lock because its the child |
| * ctx->mutex. |
| */ |
| mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); |
| |
| /* |
| * We have to re-check the event->owner field, if it is cleared |
| * we raced with perf_event_exit_task(), acquiring the mutex |
| * ensured they're done, and we can proceed with freeing the |
| * event. |
| */ |
| if (event->owner) { |
| list_del_init(&event->owner_entry); |
| smp_store_release(&event->owner, NULL); |
| } |
| mutex_unlock(&owner->perf_event_mutex); |
| put_task_struct(owner); |
| } |
| } |
| |
| static void put_event(struct perf_event *event) |
| { |
| if (!atomic_long_dec_and_test(&event->refcount)) |
| return; |
| |
| _free_event(event); |
| } |
| |
| /* |
| * Kill an event dead; while event:refcount will preserve the event |
| * object, it will not preserve its functionality. Once the last 'user' |
| * gives up the object, we'll destroy the thing. |
| */ |
| int perf_event_release_kernel(struct perf_event *event) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_event *child, *tmp; |
| |
| /* |
| * If we got here through err_file: fput(event_file); we will not have |
| * attached to a context yet. |
| */ |
| if (!ctx) { |
| WARN_ON_ONCE(event->attach_state & |
| (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); |
| goto no_ctx; |
| } |
| |
| if (!is_kernel_event(event)) |
| perf_remove_from_owner(event); |
| |
| ctx = perf_event_ctx_lock(event); |
| WARN_ON_ONCE(ctx->parent_ctx); |
| perf_remove_from_context(event, DETACH_GROUP); |
| |
| raw_spin_lock_irq(&ctx->lock); |
| /* |
| * Mark this even as STATE_DEAD, there is no external reference to it |
| * anymore. |
| * |
| * Anybody acquiring event->child_mutex after the below loop _must_ |
| * also see this, most importantly inherit_event() which will avoid |
| * placing more children on the list. |
| * |
| * Thus this guarantees that we will in fact observe and kill _ALL_ |
| * child events. |
| */ |
| event->state = PERF_EVENT_STATE_DEAD; |
| raw_spin_unlock_irq(&ctx->lock); |
| |
| perf_event_ctx_unlock(event, ctx); |
| |
| again: |
| mutex_lock(&event->child_mutex); |
| list_for_each_entry(child, &event->child_list, child_list) { |
| |
| /* |
| * Cannot change, child events are not migrated, see the |
| * comment with perf_event_ctx_lock_nested(). |
| */ |
| ctx = lockless_dereference(child->ctx); |
| /* |
| * Since child_mutex nests inside ctx::mutex, we must jump |
| * through hoops. We start by grabbing a reference on the ctx. |
| * |
| * Since the event cannot get freed while we hold the |
| * child_mutex, the context must also exist and have a !0 |
| * reference count. |
| */ |
| get_ctx(ctx); |
| |
| /* |
| * Now that we have a ctx ref, we can drop child_mutex, and |
| * acquire ctx::mutex without fear of it going away. Then we |
| * can re-acquire child_mutex. |
| */ |
| mutex_unlock(&event->child_mutex); |
| mutex_lock(&ctx->mutex); |
| mutex_lock(&event->child_mutex); |
| |
| /* |
| * Now that we hold ctx::mutex and child_mutex, revalidate our |
| * state, if child is still the first entry, it didn't get freed |
| * and we can continue doing so. |
| */ |
| tmp = list_first_entry_or_null(&event->child_list, |
| struct perf_event, child_list); |
| if (tmp == child) { |
| perf_remove_from_context(child, DETACH_GROUP); |
| list_del(&child->child_list); |
| free_event(child); |
| /* |
| * This matches the refcount bump in inherit_event(); |
| * this can't be the last reference. |
| */ |
| put_event(event); |
| } |
| |
| mutex_unlock(&event->child_mutex); |
| mutex_unlock(&ctx->mutex); |
| put_ctx(ctx); |
| goto again; |
| } |
| mutex_unlock(&event->child_mutex); |
| |
| no_ctx: |
| put_event(event); /* Must be the 'last' reference */ |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(perf_event_release_kernel); |
| |
| /* |
| * Called when the last reference to the file is gone. |
| */ |
| static int perf_release(struct inode *inode, struct file *file) |
| { |
| perf_event_release_kernel(file->private_data); |
| return 0; |
| } |
| |
| u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) |
| { |
| struct perf_event *child; |
| u64 total = 0; |
| |
| *enabled = 0; |
| *running = 0; |
| |
| mutex_lock(&event->child_mutex); |
| |
| (void)perf_event_read(event, false); |
| total += perf_event_count(event); |
| |
| *enabled += event->total_time_enabled + |
| atomic64_read(&event->child_total_time_enabled); |
| *running += event->total_time_running + |
| atomic64_read(&event->child_total_time_running); |
| |
| list_for_each_entry(child, &event->child_list, child_list) { |
| (void)perf_event_read(child, false); |
| total += perf_event_count(child); |
| *enabled += child->total_time_enabled; |
| *running += child->total_time_running; |
| } |
| mutex_unlock(&event->child_mutex); |
| |
| return total; |
| } |
| EXPORT_SYMBOL_GPL(perf_event_read_value); |
| |
| static int __perf_read_group_add(struct perf_event *leader, |
| u64 read_format, u64 *values) |
| { |
| struct perf_event *sub; |
| int n = 1; /* skip @nr */ |
| int ret; |
| |
| ret = perf_event_read(leader, true); |
| if (ret) |
| return ret; |
| |
| /* |
| * Since we co-schedule groups, {enabled,running} times of siblings |
| * will be identical to those of the leader, so we only publish one |
| * set. |
| */ |
| if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { |
| values[n++] += leader->total_time_enabled + |
| atomic64_read(&leader->child_total_time_enabled); |
| } |
| |
| if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { |
| values[n++] += leader->total_time_running + |
| atomic64_read(&leader->child_total_time_running); |
| } |
| |
| /* |
| * Write {count,id} tuples for every sibling. |
| */ |
| values[n++] += perf_event_count(leader); |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(leader); |
| |
| list_for_each_entry(sub, &leader->sibling_list, group_entry) { |
| values[n++] += perf_event_count(sub); |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(sub); |
| } |
| |
| return 0; |
| } |
| |
| static int perf_read_group(struct perf_event *event, |
| u64 read_format, char __user *buf) |
| { |
| struct perf_event *leader = event->group_leader, *child; |
| struct perf_event_context *ctx = leader->ctx; |
| int ret; |
| u64 *values; |
| |
| lockdep_assert_held(&ctx->mutex); |
| |
| values = kzalloc(event->read_size, GFP_KERNEL); |
| if (!values) |
| return -ENOMEM; |
| |
| values[0] = 1 + leader->nr_siblings; |
| |
| /* |
| * By locking the child_mutex of the leader we effectively |
| * lock the child list of all siblings.. XXX explain how. |
| */ |
| mutex_lock(&leader->child_mutex); |
| |
| ret = __perf_read_group_add(leader, read_format, values); |
| if (ret) |
| goto unlock; |
| |
| list_for_each_entry(child, &leader->child_list, child_list) { |
| ret = __perf_read_group_add(child, read_format, values); |
| if (ret) |
| goto unlock; |
| } |
| |
| mutex_unlock(&leader->child_mutex); |
| |
| ret = event->read_size; |
| if (copy_to_user(buf, values, event->read_size)) |
| ret = -EFAULT; |
| goto out; |
| |
| unlock: |
| mutex_unlock(&leader->child_mutex); |
| out: |
| kfree(values); |
| return ret; |
| } |
| |
| static int perf_read_one(struct perf_event *event, |
| u64 read_format, char __user *buf) |
| { |
| u64 enabled, running; |
| u64 values[4]; |
| int n = 0; |
| |
| values[n++] = perf_event_read_value(event, &enabled, &running); |
| if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
| values[n++] = enabled; |
| if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
| values[n++] = running; |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(event); |
| |
| if (copy_to_user(buf, values, n * sizeof(u64))) |
| return -EFAULT; |
| |
| return n * sizeof(u64); |
| } |
| |
| static bool is_event_hup(struct perf_event *event) |
| { |
| bool no_children; |
| |
| if (event->state > PERF_EVENT_STATE_EXIT) |
| return false; |
| |
| mutex_lock(&event->child_mutex); |
| no_children = list_empty(&event->child_list); |
| mutex_unlock(&event->child_mutex); |
| return no_children; |
| } |
| |
| /* |
| * Read the performance event - simple non blocking version for now |
| */ |
| static ssize_t |
| __perf_read(struct perf_event *event, char __user *buf, size_t count) |
| { |
| u64 read_format = event->attr.read_format; |
| int ret; |
| |
| /* |
| * Return end-of-file for a read on a event that is in |
| * error state (i.e. because it was pinned but it couldn't be |
| * scheduled on to the CPU at some point). |
| */ |
| if (event->state == PERF_EVENT_STATE_ERROR) |
| return 0; |
| |
| if (count < event->read_size) |
| return -ENOSPC; |
| |
| WARN_ON_ONCE(event->ctx->parent_ctx); |
| if (read_format & PERF_FORMAT_GROUP) |
| ret = perf_read_group(event, read_format, buf); |
| else |
| ret = perf_read_one(event, read_format, buf); |
| |
| return ret; |
| } |
| |
| static ssize_t |
| perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| { |
| struct perf_event *event = file->private_data; |
| struct perf_event_context *ctx; |
| int ret; |
| |
| ctx = perf_event_ctx_lock(event); |
| ret = __perf_read(event, buf, count); |
| perf_event_ctx_unlock(event, ctx); |
| |
| return ret; |
| } |
| |
| static unsigned int perf_poll(struct file *file, poll_table *wait) |
| { |
| struct perf_event *event = file->private_data; |
| struct ring_buffer *rb; |
| unsigned int events = POLLHUP; |
| |
| poll_wait(file, &event->waitq, wait); |
| |
| if (is_event_hup(event)) |
| return events; |
| |
| /* |
| * Pin the event->rb by taking event->mmap_mutex; otherwise |
| * perf_event_set_output() can swizzle our rb and make us miss wakeups. |
| */ |
| mutex_lock(&event->mmap_mutex); |
| rb = event->rb; |
| if (rb) |
| events = atomic_xchg(&rb->poll, 0); |
| mutex_unlock(&event->mmap_mutex); |
| return events; |
| } |
| |
| static void _perf_event_reset(struct perf_event *event) |
| { |
| (void)perf_event_read(event, false); |
| local64_set(&event->count, 0); |
| perf_event_update_userpage(event); |
| } |
| |
| /* |
| * Holding the top-level event's child_mutex means that any |
| * descendant process that has inherited this event will block |
| * in perf_event_exit_event() if it goes to exit, thus satisfying the |
| * task existence requirements of perf_event_enable/disable. |
| */ |
| static void perf_event_for_each_child(struct perf_event *event, |
| void (*func)(struct perf_event *)) |
| { |
| struct perf_event *child; |
| |
| WARN_ON_ONCE(event->ctx->parent_ctx); |
| |
| mutex_lock(&event->child_mutex); |
| func(event); |
| list_for_each_entry(child, &event->child_list, child_list) |
| func(child); |
| mutex_unlock(&event->child_mutex); |
| } |
| |
| static void perf_event_for_each(struct perf_event *event, |
| void (*func)(struct perf_event *)) |
| { |
| struct perf_event_context *ctx = event->ctx; |
| struct perf_event *sibling; |
| |
| lockdep_assert_held(&ctx->mutex); |
| |
| event = event->group_leader; |
| |
| perf_event_for_each_child(event, func); |
| list_for_each_entry(sibling, &event->sibling_list, group_entry) |
| perf_event_for_each_child(sibling, func); |
| } |
| |
| static void __perf_event_period(struct perf_event *event, |
| struct perf_cpu_context *cpuctx, |
| struct perf_event_context *ctx, |
| void *info) |
| { |
| u64 value = *((u64 *)info); |
| bool active; |
| |
| if (event->attr.freq) { |
| event->attr.sample_freq = value; |
| } else { |
| event->attr.sample_period = value; |
| event->hw.sample_period = value; |
| } |
| |
| active = (event->state == PERF_EVENT_STATE_ACTIVE); |
| if (active) { |
| perf_pmu_disable(ctx->pmu); |
| /* |
| * We could be throttled; unthrottle now to avoid the tick |
| * trying to unthrottle while we already re-started the event. |
| */ |
| if (event->hw.interrupts == MAX_INTERRUPTS) { |
| event->hw.interrupts = 0; |
| perf_log_throttle(event, 1); |
| } |
| event->pmu->stop(event, PERF_EF_UPDATE); |
| } |
| |
| local64_set(&event->hw.period_left, 0); |
| |
| if (active) { |
| event->pmu->start(event, PERF_EF_RELOAD); |
| perf_pmu_enable(ctx->pmu); |
| } |
| } |
| |
| static int perf_event_period(struct perf_event *event, u64 __user *arg) |
| { |
| u64 value; |
| |
| if (!is_sampling_event(event)) |
| return -EINVAL; |
| |
| if (copy_from_user(&value, arg, sizeof(value))) |
| return -EFAULT; |
| |
| if (!value) |
| return -EINVAL; |
| |
| if (event->attr.freq && value > sysctl_perf_event_sample_rate) |
| return -EINVAL; |
| |
| event_function_call(event, __perf_event_period, &value); |
| |
| return 0; |
| } |
| |
| static const struct file_operations perf_fops; |
| |
| static inline int perf_fget_light(int fd, struct fd *p) |
| { |
| struct fd f = fdget(fd); |
| if (!f.file) |
| return -EBADF; |
| |
| if (f.file->f_op != &perf_fops) { |
| fdput(f); |
| return -EBADF; |
| } |
| *p = f; |
| return 0; |
| } |
| |
| static int perf_event_set_output(struct perf_event *event, |
| struct perf_event *output_event); |
| static int perf_event_set_filter(struct perf_event *event, void __user *arg); |
| static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd); |
| |
| static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) |
| { |
| void (*func)(struct perf_event *); |
| u32 flags = arg; |
| |
| switch (cmd) { |
| case PERF_EVENT_IOC_ENABLE: |
| func = _perf_event_enable; |
| break; |
| case PERF_EVENT_IOC_DISABLE: |
| func = _perf_event_disable; |
| break; |
| case PERF_EVENT_IOC_RESET: |
| func = _perf_event_reset; |
| break; |
| |
| case PERF_EVENT_IOC_REFRESH: |
| return _perf_event_refresh(event, arg); |
| |
| case PERF_EVENT_IOC_PERIOD: |
| return perf_event_period(event, (u64 __user *)arg); |
| |
| case PERF_EVENT_IOC_ID: |
| { |
| u64 id = primary_event_id(event); |
| |
| if (copy_to_user((void __user *)arg, &id, sizeof(id))) |
| return -EFAULT; |
| return 0; |
| } |
| |
| case PERF_EVENT_IOC_SET_OUTPUT: |
| { |
| int ret; |
| if (arg != -1) { |
| struct perf_event *output_event; |
| struct fd output; |
| ret = perf_fget_light(arg, &output); |
| if (ret) |
| return ret; |
| output_event = output.file->private_data; |
| ret = perf_event_set_output(event, output_event); |
| fdput(output); |
| } else { |
| ret = perf_event_set_output(event, NULL); |
| } |
| return ret; |
| } |
| |
| case PERF_EVENT_IOC_SET_FILTER: |
| return perf_event_set_filter(event, (void __user *)arg); |
| |
| case PERF_EVENT_IOC_SET_BPF: |
| return perf_event_set_bpf_prog(event, arg); |
| |
| default: |
| return -ENOTTY; |
| } |
| |
| if (flags & PERF_IOC_FLAG_GROUP) |
| perf_event_for_each(event, func); |
| else |
| perf_event_for_each_child(event, func); |
| |
| return 0; |
| } |
| |
| static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct perf_event *event = file->private_data; |
| struct perf_event_context *ctx; |
| long ret; |
| |
| ctx = perf_event_ctx_lock(event); |
| ret = _perf_ioctl(event, cmd, arg); |
| perf_event_ctx_unlock(event, ctx); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long perf_compat_ioctl(struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| switch (_IOC_NR(cmd)) { |
| case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): |
| case _IOC_NR(PERF_EVENT_IOC_ID): |
| /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ |
| if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { |
| cmd &= ~IOCSIZE_MASK; |
| cmd |= sizeof(void *) << IOCSIZE_SHIFT; |
| } |
| break; |
| } |
| return perf_ioctl(file, cmd, arg); |
| } |
| #else |
| # define perf_compat_ioctl NULL |
| #endif |
| |
| int perf_event_task_enable(void) |
| { |
| struct perf_event_context *ctx; |
| struct perf_event *event; |
| |
| mutex_lock(¤t->perf_event_mutex); |
| list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { |
| ctx = perf_event_ctx_lock(event); |
| perf_event_for_each_child(event, _perf_event_enable); |
| perf_event_ctx_unlock(event, ctx); |
| } |
| mutex_unlock(¤t->perf_event_mutex); |
| |
| return 0; |
| } |
| |
| int perf_event_task_disable(void) |
| { |
| struct perf_event_context *ctx; |
| struct perf_event *event; |
| |
| mutex_lock(¤t->perf_event_mutex); |
| list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { |
| ctx = perf_event_ctx_lock(event); |
| perf_event_for_each_child(event, _perf_event_disable); |
| perf_event_ctx_unlock(event, ctx); |
| } |
| mutex_unlock(¤t->perf_event_mutex); |
| |
| return 0; |
| } |
| |
| static int perf_event_index(struct perf_event *event) |
| { |
| if (event->hw.state & PERF_HES_STOPPED) |
| return 0; |
| |
| if (event->state != PERF_EVENT_STATE_ACTIVE) |
| return 0; |
| |
| return event->pmu->event_idx(event); |
| } |
| |
| static void calc_timer_values(struct perf_event *event, |
| u64 *now, |
| u64 *enabled, |
| u64 *running) |
| { |
| u64 ctx_time; |
| |
| *now = perf_clock(); |
| ctx_time = event->shadow_ctx_time + *now; |
| *enabled = ctx_time - event->tstamp_enabled; |
| *running = ctx_time - event->tstamp_running; |
| } |
| |
| static void perf_event_init_userpage(struct perf_event *event) |
| { |
| struct perf_event_mmap_page *userpg; |
| struct ring_buffer *rb; |
| |
| rcu_read_lock(); |
| rb = rcu_dereference(event->rb); |
| if (!rb) |
| goto unlock; |
| |
| userpg = rb->user_page; |
| |
| /* Allow new userspace to detect that bit 0 is deprecated */ |
| userpg->cap_bit0_is_deprecated = 1; |
| userpg->size = offsetof(struct perf_event_mmap_page, __reserved); |
| userpg->data_offset = PAGE_SIZE; |
| userpg->data_size = perf_data_size(rb); |
| |
| unlock: |
| rcu_read_unlock(); |
| } |
| |
| void __weak arch_perf_update_userpage( |
| struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) |
| { |
| } |
| |
| /* |
| * Callers need to ensure there can be no nesting of this function, otherwise |
| * the seqlock logic goes bad. We can not serialize this because the arch |
| * code calls this from NMI context. |
| */ |
| void perf_event_update_userpage(struct perf_event *event) |
| { |
| struct perf_event_mmap_page *userpg; |
| struct ring_buffer *rb; |
| u64 enabled, running, now; |
| |
| rcu_read_lock(); |
| rb = rcu_dereference(event->rb); |
| if (!rb) |
| goto unlock; |
| |
| /* |
| * compute total_time_enabled, total_time_running |
| * based on snapshot values taken when the event |
| * was last scheduled in. |
| * |
| * we cannot simply called update_context_time() |
| * because of locking issue as we can be called in |
| * NMI context |
| */ |
| calc_timer_values(event, &now, &enabled, &running); |
| |
| userpg = rb->user_page; |
| /* |
| * Disable preemption so as to not let the corresponding user-space |
| * spin too long if we get preempted. |
| */ |
| preempt_disable(); |
| ++userpg->lock; |
| barrier(); |
| userpg->index = perf_event_index(event); |
| userpg->offset = perf_event_count(event); |
| if (userpg->index) |
| userpg->offset -= local64_read(&event->hw.prev_count); |
| |
| userpg->time_enabled = enabled + |
| atomic64_read(&event->child_total_time_enabled); |
| |
| userpg->time_running = running + |
| atomic64_read(&event->child_total_time_running); |
| |
| arch_perf_update_userpage(event, userpg, now); |
| |
| barrier(); |
| ++userpg->lock; |
| preempt_enable(); |
| unlock: |
| rcu_read_unlock(); |
| } |
| |
| static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| { |
| struct perf_event *event = vma->vm_file->private_data; |
| struct ring_buffer *rb; |
| int ret = VM_FAULT_SIGBUS; |
| |
| if (vmf->flags & FAULT_FLAG_MKWRITE) { |
| if (vmf->pgoff == 0) |
| ret = 0; |
| return ret; |
| } |
| |
| rcu_read_lock(); |
| rb = rcu_dereference(event->rb); |
| if (!rb) |
| goto unlock; |
| |
| if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) |
| goto unlock; |
| |
| vmf->page = perf_mmap_to_page(rb, vmf->pgoff); |
| if (!vmf->page) |
| goto unlock; |
| |
| get_page(vmf->page); |
| vmf->page->mapping = vma->vm_file->f_mapping; |
| vmf->page->index = vmf->pgoff; |
| |
| ret = 0; |
| unlock: |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| static void ring_buffer_attach(struct perf_event *event, |
| struct ring_buffer *rb) |
| { |
| struct ring_buffer *old_rb = NULL; |
| unsigned long flags; |
| |
| if (event->rb) { |
| /* |
| * Should be impossible, we set this when removing |
| * event->rb_entry and wait/clear when adding event->rb_entry. |
| */ |
| WARN_ON_ONCE(event->rcu_pending); |
| |
| old_rb = event->rb; |
| spin_lock_irqsave(&old_rb->event_lock, flags); |
| list_del_rcu(&event->rb_entry); |
| spin_unlock_irqrestore(&old_rb->event_lock, flags); |
| |
| event->rcu_batches = get_state_synchronize_rcu(); |
| event->rcu_pending = 1; |
| } |
| |
| if (rb) { |
| if (event->rcu_pending) { |
| cond_synchronize_rcu(event->rcu_batches); |
| event->rcu_pending = 0; |
| } |
| |
| spin_lock_irqsave(&rb->event_lock, flags); |
| list_add_rcu(&event->rb_entry, &rb->event_list); |
| spin_unlock_irqrestore(&rb->event_lock, flags); |
| } |
| |
| rcu_assign_pointer(event->rb, rb); |
| |
| if (old_rb) { |
| ring_buffer_put(old_rb); |
| /* |
| * Since we detached before setting the new rb, so that we |
| * could attach the new rb, we could have missed a wakeup. |
| * Provide it now. |
| */ |
| wake_up_all(&event->waitq); |
| } |
| } |
| |
| static void ring_buffer_wakeup(struct perf_event *event) |
| { |
| struct ring_buffer *rb; |
| |
| rcu_read_lock(); |
| rb = rcu_dereference(event->rb); |
| if (rb) { |
| list_for_each_entry_rcu(event, &rb->event_list, rb_entry) |
| wake_up_all(&event->waitq); |
| } |
| rcu_read_unlock(); |
| } |
| |
| struct ring_buffer *ring_buffer_get(struct perf_event *event) |
| { |
| struct ring_buffer *rb; |
| |
| rcu_read_lock(); |
| rb = rcu_dereference(event->rb); |
| if (rb) { |
| if (!atomic_inc_not_zero(&rb->refcount)) |
| rb = NULL; |
| } |
| rcu_read_unlock(); |
| |
| return rb; |
| } |
| |
| void ring_buffer_put(struct ring_buffer *rb) |
| { |
| if (!atomic_dec_and_test(&rb->refcount)) |
| return; |
| |
| WARN_ON_ONCE(!list_empty(&rb->event_list)); |
| |
| call_rcu(&rb->rcu_head, rb_free_rcu); |
| } |
| |
| static void perf_mmap_open(struct vm_area_struct *vma) |
| { |
| struct perf_event *event = vma->vm_file->private_data; |
| |
| atomic_inc(&event->mmap_count); |
| atomic_inc(&event->rb->mmap_count); |
| |
| if (vma->vm_pgoff) |
| atomic_inc(&event->rb->aux_mmap_count); |
| |
| if (event->pmu->event_mapped) |
| event->pmu->event_mapped(event); |
| } |
| |
| /* |
| * A buffer can be mmap()ed multiple times; either directly through the same |
| * event, or through other events by use of perf_event_set_output(). |
| * |
| * In order to undo the VM accounting done by perf_mmap() we need to destroy |
| * the buffer here, where we still have a VM context. This means we need |
| * to detach all events redirecting to us. |
| */ |
| static void perf_mmap_close(struct vm_area_struct *vma) |
| { |
| struct perf_event *event = vma->vm_file->private_data; |
| |
| struct ring_buffer *rb = ring_buffer_get(event); |
| struct user_struct *mmap_user = rb->mmap_user; |
| int mmap_locked = rb->mmap_locked; |
| unsigned long size = perf_data_size(rb); |
| |
| if (event->pmu->event_unmapped) |
| event->pmu->event_unmapped(event); |
| |
| /* |
| * rb->aux_mmap_count will always drop before rb->mmap_count and |
| * event->mmap_count, so it is ok to use event->mmap_mutex to |
| * serialize with perf_mmap here. |
| */ |
| if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && |
| atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { |
| atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); |
| vma->vm_mm->pinned_vm -= rb->aux_mmap_locked; |
| |
| rb_free_aux(rb); |
| mutex_unlock(&event->mmap_mutex); |
| } |
| |
| atomic_dec(&rb->mmap_count); |
| |
| if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) |
| goto out_put; |
| |
| ring_buffer_attach(event, NULL); |
| mutex_unlock(&event->mmap_mutex); |
| |
| /* If there's still other mmap()s of this buffer, we're done. */ |
| if (atomic_read(&rb->mmap_count)) |
| goto out_put; |
| |
| /* |
| * No other mmap()s, detach from all other events that might redirect |
| * into the now unreachable buffer. Somewhat complicated by the |
| * fact that rb::event_lock otherwise nests inside mmap_mutex. |
| */ |
| again: |
| rcu_read_lock(); |
| list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { |
| if (!atomic_long_inc_not_zero(&event->refcount)) { |
| /* |
| * This event is en-route to free_event() which will |
| * detach it and remove it from the list. |
| */ |
| continue; |
| } |
| rcu_read_unlock(); |
| |
| mutex_lock(&event->mmap_mutex); |
| /* |
| * Check we didn't race with perf_event_set_output() which can |
| * swizzle the rb from under us while we were waiting to |
| * acquire mmap_mutex. |
| * |
| * If we find a different rb; ignore this event, a next |
| * iteration will no longer find it on the list. We have to |
| * still restart the iteration to make sure we're not now |
| * iterating the wrong list. |
| */ |
| if (event->rb == rb) |
| ring_buffer_attach(event, NULL); |
| |
| mutex_unlock(&event->mmap_mutex); |
| put_event(event); |
| |
| /* |
| * Restart the iteration; either we're on the wrong list or |
| * destroyed its integrity by doing a deletion. |
| */ |
| goto again; |
| } |
| rcu_read_unlock(); |
| |
| /* |
| * It could be there's still a few 0-ref events on the list; they'll |
| * get cleaned up by free_event() -- they'll also still have their |
| * ref on the rb and will free it whenever they are done with it. |
| * |
| * Aside from that, this buffer is 'fully' detached and unmapped, |
| * undo the VM accounting. |
| */ |
| |
| atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); |
| vma->vm_mm->pinned_vm -= mmap_locked; |
| free_uid(mmap_user); |
| |
| out_put: |
| ring_buffer_put(rb); /* could be last */ |
| } |
| |
| static const struct vm_operations_struct perf_mmap_vmops = { |
| .open = perf_mmap_open, |
| .close = perf_mmap_close, /* non mergable */ |
| .fault = perf_mmap_fault, |
| .page_mkwrite = perf_mmap_fault, |
| }; |
| |
| static int perf_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| struct perf_event *event = file->private_data; |
| unsigned long user_locked, user_lock_limit; |
| struct user_struct *user = current_user(); |
| unsigned long locked, lock_limit; |
| struct ring_buffer *rb = NULL; |
| unsigned long vma_size; |
| unsigned long nr_pages; |
| long user_extra = 0, extra = 0; |
| int ret = 0, flags = 0; |
| |
| /* |
| * Don't allow mmap() of inherited per-task counters. This would |
| * create a performance issue due to all children writing to the |
| * same rb. |
| */ |
| if (event->cpu == -1 && event->attr.inherit) |
| return -EINVAL; |
| |
| if (!(vma->vm_flags & VM_SHARED)) |
| return -EINVAL; |
| |
| vma_size = vma->vm_end - vma->vm_start; |
| |
| if (vma->vm_pgoff == 0) { |
| nr_pages = (vma_size / PAGE_SIZE) - 1; |
| } else { |
| /* |
| * AUX area mapping: if rb->aux_nr_pages != 0, it's already |
| * mapped, all subsequent mappings should have the same size |
| * and offset. Must be above the normal perf buffer. |
| */ |
| u64 aux_offset, aux_size; |
| |
| if (!event->rb) |
| return -EINVAL; |
| |
| nr_pages = vma_size / PAGE_SIZE; |
| |
| mutex_lock(&event->mmap_mutex); |
| ret = -EINVAL; |
| |
| rb = event->rb; |
| if (!rb) |
| goto aux_unlock; |
| |
| aux_offset = ACCESS_ONCE(rb->user_page->aux_offset); |
| aux_size = ACCESS_ONCE(rb->user_page->aux_size); |
| |
| if (aux_offset < perf_data_size(rb) + PAGE_SIZE) |
| goto aux_unlock; |
| |
| if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) |
| goto aux_unlock; |
| |
| /* already mapped with a different offset */ |
| if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) |
| goto aux_unlock; |
| |
| if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) |
| goto aux_unlock; |
| |
| /* already mapped with a different size */ |
| if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) |
| goto aux_unlock; |
| |
| if (!is_power_of_2(nr_pages)) |
| goto aux_unlock; |
| |
| if (!atomic_inc_not_zero(&rb->mmap_count)) |
| goto aux_unlock; |
| |
| if (rb_has_aux(rb)) { |
| atomic_inc(&rb->aux_mmap_count); |
| ret = 0; |
| goto unlock; |
| } |
| |
| atomic_set(&rb->aux_mmap_count, 1); |
| user_extra = nr_pages; |
| |
| goto accounting; |
| } |
| |
| /* |
| * If we have rb pages ensure they're a power-of-two number, so we |
| * can do bitmasks instead of modulo. |
| */ |
| if (nr_pages != 0 && !is_power_of_2(nr_pages)) |
| return -EINVAL; |
| |
| if (vma_size != PAGE_SIZE * (1 + nr_pages)) |
| return -EINVAL; |
| |
| WARN_ON_ONCE(event->ctx->parent_ctx); |
| again: |
| mutex_lock(&event->mmap_mutex); |
| if (event->rb) { |
| if (event->rb->nr_pages != nr_pages) { |
| ret = -EINVAL; |
| goto unlock; |
| } |
| |
| if (!atomic_inc_not_zero(&event->rb->mmap_count)) { |
| /* |
| * Raced against perf_mmap_close() through |
| * perf_event_set_output(). Try again, hope for better |
| * luck. |
| */ |
| mutex_unlock(&event->mmap_mutex); |
| goto again; |
| } |
| |
| goto unlock; |
| } |
| |
| user_extra = nr_pages + 1; |
| |
| accounting: |
| user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); |
| |
| /* |
| * Increase the limit linearly with more CPUs: |
| */ |
| user_lock_limit *= num_online_cpus(); |
| |
| user_locked = atomic_long_read(&user->locked_vm) + user_extra; |
| |
| if (user_locked > user_lock_limit) |
| extra = user_locked - user_lock_limit; |
| |
| lock_limit = rlimit(RLIMIT_MEMLOCK); |
| lock_limit >>= PAGE_SHIFT; |
| locked = vma->vm_mm->pinned_vm + extra; |
| |
| if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && |
| !capable(CAP_IPC_LOCK)) { |
| ret = -EPERM; |
| goto unlock; |
| } |
| |
| WARN_ON(!rb && event->rb); |
| |
| if (vma->vm_flags & VM_WRITE) |
| flags |= RING_BUFFER_WRITABLE; |
| |
| if (!rb) { |
| rb = rb_alloc(nr_pages, |
| event->attr.watermark ? event->attr.wakeup_watermark : 0, |
| event->cpu, flags); |
| |
| if (!rb) { |
| ret = -ENOMEM; |
| goto unlock; |
| } |
| |
| atomic_set(&rb->mmap_count, 1); |
| rb->mmap_user = get_current_user(); |
| rb->mmap_locked = extra; |
| |
| ring_buffer_attach(event, rb); |
| |
| perf_event_init_userpage(event); |
| perf_event_update_userpage(event); |
| } else { |
| ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, |
| event->attr.aux_watermark, flags); |
| if (!ret) |
| rb->aux_mmap_locked = extra; |
| } |
| |
| unlock: |
| if (!ret) { |
| atomic_long_add(user_extra, &user->locked_vm); |
| vma->vm_mm->pinned_vm += extra; |
| |
| atomic_inc(&event->mmap_count); |
| } else if (rb) { |
| atomic_dec(&rb->mmap_count); |
| } |
| aux_unlock: |
| mutex_unlock(&event->mmap_mutex); |
| |
| /* |
| * Since pinned accounting is per vm we cannot allow fork() to copy our |
| * vma. |
| */ |
| vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; |
| vma->vm_ops = &perf_mmap_vmops; |
| |
| if (event->pmu->event_mapped) |
| event->pmu->event_mapped(event); |
| |
| return ret; |
| } |
| |
| static int perf_fasync(int fd, struct file *filp, int on) |
| { |
| struct inode *inode = file_inode(filp); |
| struct perf_event *event = filp->private_data; |
| int retval; |
| |
| inode_lock(inode); |
| retval = fasync_helper(fd, filp, on, &event->fasync); |
| inode_unlock(inode); |
| |
| if (retval < 0) |
| return retval; |
| |
| return 0; |
| } |
| |
| static const struct file_operations perf_fops = { |
| .llseek = no_llseek, |
| .release = perf_release, |
| .read = perf_read, |
| .poll = perf_poll, |
| .unlocked_ioctl = perf_ioctl, |
| .compat_ioctl = perf_compat_ioctl, |
| .mmap = perf_mmap, |
| .fasync = perf_fasync, |
| }; |
| |
| /* |
| * Perf event wakeup |
| * |
| * If there's data, ensure we set the poll() state and publish everything |
| * to user-space before waking everybody up. |
| */ |
| |
| static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) |
| { |
| /* only the parent has fasync state */ |
| if (event->parent) |
| event = event->parent; |
| return &event->fasync; |
| } |
| |
| void perf_event_wakeup(struct perf_event *event) |
| { |
| ring_buffer_wakeup(event); |
| |
| if (event->pending_kill) { |
| kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); |
| event->pending_kill = 0; |
| } |
| } |
| |
| static void perf_pending_event(struct irq_work *entry) |
| { |
| struct perf_event *event = container_of(entry, |
| struct perf_event, pending); |
| int rctx; |
| |
| rctx = perf_swevent_get_recursion_context(); |
| /* |
| * If we 'fail' here, that's OK, it means recursion is already disabled |
| * and we won't recurse 'further'. |
| */ |
| |
| if (event->pending_disable) { |
| event->pending_disable = 0; |
| perf_event_disable_local(event); |
| } |
| |
| if (event->pending_wakeup) { |
| event->pending_wakeup = 0; |
| perf_event_wakeup(event); |
| } |
| |
| if (rctx >= 0) |
| perf_swevent_put_recursion_context(rctx); |
| } |
| |
| /* |
| * We assume there is only KVM supporting the callbacks. |
| * Later on, we might change it to a list if there is |
| * another virtualization implementation supporting the callbacks. |
| */ |
| struct perf_guest_info_callbacks *perf_guest_cbs; |
| |
| int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) |
| { |
| perf_guest_cbs = cbs; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); |
| |
| int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) |
| { |
| perf_guest_cbs = NULL; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); |
| |
| static void |
| perf_output_sample_regs(struct perf_output_handle *handle, |
| struct pt_regs *regs, u64 mask) |
| { |
| int bit; |
| |
| for_each_set_bit(bit, (const unsigned long *) &mask, |
| sizeof(mask) * BITS_PER_BYTE) { |
| u64 val; |
| |
| val = perf_reg_value(regs, bit); |
| perf_output_put(handle, val); |
| } |
| } |
| |
| static void perf_sample_regs_user(struct perf_regs *regs_user, |
| struct pt_regs *regs, |
| struct pt_regs *regs_user_copy) |
| { |
| if (user_mode(regs)) { |
| regs_user->abi = perf_reg_abi(current); |
| regs_user->regs = regs; |
| } else if (current->mm) { |
| perf_get_regs_user(regs_user, regs, regs_user_copy); |
| } else { |
| regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; |
| regs_user->regs = NULL; |
| } |
| } |
| |
| static void perf_sample_regs_intr(struct perf_regs *regs_intr, |
| struct pt_regs *regs) |
| { |
| regs_intr->regs = regs; |
| regs_intr->abi = perf_reg_abi(current); |
| } |
| |
| |
| /* |
| * Get remaining task size from user stack pointer. |
| * |
| * It'd be better to take stack vma map and limit this more |
| * precisly, but there's no way to get it safely under interrupt, |
| * so using TASK_SIZE as limit. |
| */ |
| static u64 perf_ustack_task_size(struct pt_regs *regs) |
| { |
| unsigned long addr = perf_user_stack_pointer(regs); |
| |
| if (!addr || addr >= TASK_SIZE) |
| return 0; |
| |
| return TASK_SIZE - addr; |
| } |
| |
| static u16 |
| perf_sample_ustack_size(u16 stack_size, u16 header_size, |
| struct pt_regs *regs) |
| { |
| u64 task_size; |
| |
| /* No regs, no stack pointer, no dump. */ |
| if (!regs) |
| return 0; |
| |
| /* |
| * Check if we fit in with the requested stack size into the: |
| * - TASK_SIZE |
| * If we don't, we limit the size to the TASK_SIZE. |
| * |
| * - remaining sample size |
| * If we don't, we customize the stack size to |
| * fit in to the remaining sample size. |
| */ |
| |
| task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); |
| stack_size = min(stack_size, (u16) task_size); |
| |
| /* Current header size plus static size and dynamic size. */ |
| header_size += 2 * sizeof(u64); |
| |
| /* Do we fit in with the current stack dump size? */ |
| if ((u16) (header_size + stack_size) < header_size) { |
| /* |
| * If we overflow the maximum size for the sample, |
| * we customize the stack dump size to fit in. |
| */ |
| stack_size = USHRT_MAX - header_size - sizeof(u64); |
| stack_size = round_up(stack_size, sizeof(u64)); |
| } |
| |
| return stack_size; |
| } |
| |
| static void |
| perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, |
| struct pt_regs *regs) |
| { |
| /* Case of a kernel thread, nothing to dump */ |
| if (!regs) { |
| u64 size = 0; |
| perf_output_put(handle, size); |
| } else { |
| unsigned long sp; |
| unsigned int rem; |
| u64 dyn_size; |
| |
| /* |
| * We dump: |
| * static size |
| * - the size requested by user or the best one we can fit |
| * in to the sample max size |
| * data |
| * - user stack dump data |
| * dynamic size |
| * - the actual dumped size |
| */ |
| |
| /* Static size. */ |
| perf_output_put(handle, dump_size); |
| |
| /* Data. */ |
| sp = perf_user_stack_pointer(regs); |
| rem = __output_copy_user(handle, (void *) sp, dump_size); |
| dyn_size = dump_size - rem; |
| |
| perf_output_skip(handle, rem); |
| |
| /* Dynamic size. */ |
| perf_output_put(handle, dyn_size); |
| } |
| } |
| |
| static void __perf_event_header__init_id(struct perf_event_header *header, |
| struct perf_sample_data *data, |
| struct perf_event *event) |
| { |
| u64 sample_type = event->attr.sample_type; |
| |
| data->type = sample_type; |
| header->size += event->id_header_size; |
| |
| if (sample_type & PERF_SAMPLE_TID) { |
| /* namespace issues */ |
| data->tid_entry.pid = perf_event_pid(event, current); |
| data->tid_entry.tid = perf_event_tid(event, current); |
| } |
| |
| if (sample_type & PERF_SAMPLE_TIME) |
| data->time = perf_event_clock(event); |
| |
| if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) |
| data->id = primary_event_id(event); |
| |
| if (sample_type & PERF_SAMPLE_STREAM_ID) |
| data->stream_id = event->id; |
| |
| if (sample_type & PERF_SAMPLE_CPU) { |
| data->cpu_entry.cpu = raw_smp_processor_id(); |
| data->cpu_entry.reserved = 0; |
| } |
| } |
| |
| void perf_event_header__init_id(struct perf_event_header *header, |
| struct perf_sample_data *data, |
| struct perf_event *event) |
| { |
| if (event->attr.sample_id_all) |
| __perf_event_header__init_id(header, data, event); |
| } |
| |
| static void __perf_event__output_id_sample(struct perf_output_handle *handle, |
| struct perf_sample_data *data) |
| { |
| u64 sample_type = data->type; |
| |
| if (sample_type & PERF_SAMPLE_TID) |
| perf_output_put(handle, data->tid_entry); |
| |
| if (sample_type & PERF_SAMPLE_TIME) |
| perf_output_put(handle, data->time); |
| |
| if (sample_type & PERF_SAMPLE_ID) |
| perf_output_put(handle, data->id); |
| |
| if (sample_type & PERF_SAMPLE_STREAM_ID) |
| perf_output_put(handle, data->stream_id); |
| |
| if (sample_type & PERF_SAMPLE_CPU) |
| perf_output_put(handle, data->cpu_entry); |
| |
| if (sample_type & PERF_SAMPLE_IDENTIFIER) |
| perf_output_put(handle, data->id); |
| } |
| |
| void perf_event__output_id_sample(struct perf_event *event, |
| struct perf_output_handle *handle, |
| struct perf_sample_data *sample) |
| { |
| if (event->attr.sample_id_all) |
| __perf_event__output_id_sample(handle, sample); |
| } |
| |
| static void perf_output_read_one(struct perf_output_handle *handle, |
| struct perf_event *event, |
| u64 enabled, u64 running) |
| { |
| u64 read_format = event->attr.read_format; |
| u64 values[4]; |
| int n = 0; |
| |
| values[n++] = perf_event_count(event); |
| if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { |
| values[n++] = enabled + |
| atomic64_read(&event->child_total_time_enabled); |
| } |
| if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { |
| values[n++] = running + |
| atomic64_read(&event->child_total_time_running); |
| } |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(event); |
| |
| __output_copy(handle, values, n * sizeof(u64)); |
| } |
| |
| /* |
| * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. |
| */ |
| static void perf_output_read_group(struct perf_output_handle *handle, |
| struct perf_event *event, |
| u64 enabled, u64 running) |
| { |
| struct perf_event *leader = event->group_leader, *sub; |
| u64 read_format = event->attr.read_format; |
| u64 values[5]; |
| int n = 0; |
| |
| values[n++] = 1 + leader->nr_siblings; |
| |
| if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
| values[n++] = enabled; |
| |
| if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
| values[n++] = running; |
| |
| if (leader != event) |
| leader->pmu->read(leader); |
| |
| values[n++] = perf_event_count(leader); |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(leader); |
| |
| __output_copy(handle, values, n * sizeof(u64)); |
| |
| list_for_each_entry(sub, &leader->sibling_list, group_entry) { |
| n = 0; |
| |
| if ((sub != event) && |
| (sub->state == PERF_EVENT_STATE_ACTIVE)) |
| sub->pmu->read(sub); |
| |
| values[n++] = perf_event_count(sub); |
| if (read_format & PERF_FORMAT_ID) |
| values[n++] = primary_event_id(sub); |
| |
| __output_copy(handle, values, n * sizeof(u64)); |
| } |
| } |
| |
| #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ |
| PERF_FORMAT_TOTAL_TIME_RUNNING) |
| |
| static void perf_output_read(struct perf_output_handle *handle, |
| struct perf_event *event) |
| { |
| u64 enabled = 0, running = 0, now; |
| u64 read_format = event->attr.read_format; |
| |
| /* |
| * compute total_time_enabled, total_time_running |
| * based on snapshot values taken when the event |
| * was last scheduled in. |
| * |
| * we cannot simply called update_context_time() |
| * because of locking issue as we are called in |
| * NMI context |
| */ |
| if (read_format & PERF_FORMAT_TOTAL_TIMES) |
| calc_timer_values(event, &now, &enabled, &running); |
| |
| if (event->attr.read_format & PERF_FORMAT_GROUP) |
| perf_output_read_group(handle, event, enabled, running); |
| else |
| perf_output_read_one(handle, event, enabled, running); |
| } |
| |
| void perf_output_sample(struct perf_output_handle *handle, |
| struct perf_event_header *header, |
| struct perf_sample_data *data, |
| struct perf_event *event) |
| { |
| u64 sample_type = data->type; |
| |
| perf_output_put(handle, *header); |
| |
| if (sample_type & PERF_SAMPLE_IDENTIFIER) |
| perf_output_put(handle, data->id); |
| |
| if (sample_type & PERF_SAMPLE_IP) |
| perf_output_put(handle, data->ip); |
| |
| if (sample_type & PERF_SAMPLE_TID) |
| perf_output_put(handle, data->tid_entry); |
| |
| if (sample_type & PERF_SAMPLE_TIME) |
| perf_output_put(handle, data->time); |
| |
| if (sample_type & PERF_SAMPLE_ADDR) |
| perf_output_put(handle, data->addr); |
| |
| if (sample_type & PERF_SAMPLE_ID) |
| perf_output_put(handle, data->id); |
| |
| if (sample_type & PERF_SAMPLE_STREAM_ID) |
| perf_output_put(handle, data->stream_id); |
| |
| if (sample_type & PERF_SAMPLE_CPU) |
| perf_output_put(handle, data->cpu_entry); |
| |
| if (sample_type & PERF_SAMPLE_PERIOD) |
| perf_output_put(handle, data->period); |
| |
| if (sample_type & PERF_SAMPLE_READ) |
| perf_output_read(handle, event); |
| |
| if (sample_type & PERF_SAMPLE_CALLCHAIN) { |
| if (data->callchain) { |
| int size = 1; |
| |
| if (data->callchain) |
| size += data->callchain->nr; |
| |
| size *= sizeof(u64); |
| |
| __output_copy(handle, data->callchain, size); |
| } else { |
| u64 nr = 0; |
| perf_output_put(handle, nr); |
| } |
| } |
| |
| if (sample_type & PERF_SAMPLE_RAW) { |
| if (data->raw) { |
| u32 raw_size = data->raw->size; |
| u32 real_size = round_up(raw_size + sizeof(u32), |
| sizeof(u64)) - sizeof(u32); |
| u64 zero = 0; |
| |
| perf_output_put(handle, real_size); |
| __output_copy(handle, data->raw->data, raw_size); |
| if (real_size - raw_size) |
| __output_copy(handle, &zero, real_size - raw_size); |
| } else { |
| struct { |
| u32 size; |
| u32 data; |
| } raw = { |
| .size = sizeof(u32), |
| .data = 0, |
| }; |
| perf_output_put(handle, raw); |
| } |
| } |
| |
| if (sample_type & PERF_SAMPLE_BRANCH_STACK) { |
| if (data->br_stack) { |
| size_t size; |
| |
| size = data->br_stack->nr |
| * sizeof(struct perf_branch_entry); |
| |
| perf_output_put(handle, data->br_stack->nr); |
| perf_output_copy(handle, data->br_stack->entries, size); |
| } else { |
| /* |
| * we always store at least the value of nr |
| */ |
| u64 nr = 0; |
| perf_output_put(handle, nr); |
| } |
| } |
| |
| if (sample_type & PERF_SAMPLE_REGS_USER) { |
| u64 abi = data->regs_user.abi; |
| |
| /* |
| * If there are no regs to dump, notice it through |
| * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). |
| */ |
| perf_output_put(handle, abi); |
| |
| if (abi) { |
| u64 mask = event->attr.sample_regs_user; |
| perf_output_sample_regs(handle, |
| data->regs_user.regs, |
| mask); |
| } |
| } |
| |
| if (sample_type & PERF_SAMPLE_STACK_USER) { |
| perf_output_sample_ustack(handle, |
| data->stack_user_size, |
| data->regs_user.regs); |
| } |
| |
| if (sample_type & PERF_SAMPLE_WEIGHT) |
| perf_output_put(handle, data->weight); |
| |
| if (sample_type & PERF_SAMPLE_DATA_SRC) |
| perf_output_put(handle, data->data_src.val); |
| |
| if (sample_type & PERF_SAMPLE_TRANSACTION) |
| perf_output_put(handle, data->txn); |
| |
| if (sample_type & PERF_SAMPLE_REGS_INTR) { |
| u64 abi = data->regs_intr.abi; |
| /* |
| * If there are no regs to dump, notice it through |
| * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). |
| */ |
| perf_output_put(handle, abi); |
| |
| if (abi) { |
| u64 mask = event->attr.sample_regs_intr; |
| |
| perf_output_sample_regs(handle, |
| data->regs_intr.regs, |
| mask); |
| } |
| } |
| |
| if (!event->attr.watermark) { |
| int wakeup_events = event->attr.wakeup_events; |
| |
| if (wakeup_events) { |
| struct ring_buffer *rb = handle->rb; |
| int events = local_inc_return(&rb->events); |
| |
| if (events >= wakeup_events) { |
| local_sub(wakeup_events, &rb->events); |
| local_inc(&rb->wakeup); |
| } |
| } |
| } |
| } |
| |
| void perf_prepare_sample(struct perf_event_header *header, |
| struct perf_sample_data *data, |
| struct perf_event *event, |
| struct pt_regs *regs) |
| { |
| u64 sample_type = event->attr.sample_type; |
| |
| header->type = PERF_RECORD_SAMPLE; |
| header->size = sizeof(*header) + event->header_size; |
| |
| header->misc = 0; |
| header->misc |= perf_misc_flags(regs); |
| |
| __perf_event_header__init_id(header, data, event); |
| |
| if (sample_type & PERF_SAMPLE_IP) |
| data->ip = perf_instruction_pointer(regs); |
| |
| if (sample_type & PERF_SAMPLE_CALLCHAIN) { |
| int size = 1; |
| |
| data->callchain = perf_callchain(event, regs); |
| |
| if (data->callchain) |
| size += data->callchain->nr; |
| |
| header->size += size * sizeof(u64); |
| } |
| |
| if (sample_type & PERF_SAMPLE_RAW) { |
| int size = sizeof(u32); |
| |
| if (data->raw) |
| size += data->raw->size; |
| else |
| size += sizeof(u32); |
| |
| header->size += round_up(size, sizeof(u64)); |
| } |
| |
| if (sample_type & PERF_SAMPLE_BRANCH_STACK) { |
| int size = sizeof(u64); /* nr */ |
| if (data->br_stack) { |
| size += data->br_stack->nr |
| * sizeof(struct perf_branch_entry); |
| } |
| header->size += size; |
| } |
| |
| if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) |
| perf_sample_regs_user(&data->regs_user, regs, |
| &data->regs_user_copy); |
| |
| if (sample_type & PERF_SAMPLE_REGS_USER) { |
| /* regs dump ABI info */ |
| int size = sizeof(u64); |
| |
| if (data->regs_user.regs) { |
| u64 mask = event->attr.sample_regs_user; |
| size += hweight64(mask) * sizeof(u64); |
| } |
| |
| header->size += size; |
| } |
| |
| if (sample_type & PERF_SAMPLE_STACK_USER) { |
| /* |
| * Either we need PERF_SAMPLE_STACK_USER bit to be allways |
| * processed as the last one or have additional check added |
| * in case new sample type is added, because we could eat |
| * up the rest of the sample size. |
| */ |
| u16 stack_size = event->attr.sample_stack_user; |
| u16 size = sizeof(u64); |
| |
| stack_size = perf_sample_ustack_size(stack_size, header->size, |
| data->regs_user.regs); |
| |
| /* |
| * If there is something to dump, add space for the dump |
| * itself and for the field that tells the dynamic size, |
| * which is how many have been actually dumped. |
| */ |
| if (stack_size) |
| size += sizeof(u64) + stack_size; |
| |
| data->stack_user_size = stack_size; |
| header->size += size; |
| } |
| |
| if (sample_type & PERF_SAMPLE_REGS_INTR) { |
| /* regs dump ABI info */ |
| int size = sizeof(u64); |
| |
| perf_sample_regs_intr(&data->regs_intr, regs); |
| |
| if (data->regs_intr.regs) { |
| u64 mask = event->attr.sample_regs_intr; |
| |
| size += hweight64(mask) * sizeof(u64); |
| } |
| |
| header->size += size; |
| } |
| } |
| |
| void perf_event_output(struct perf_event *event, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| struct perf_output_handle handle; |
| struct perf_event_header header; |
| |
| /* protect the callchain buffers */ |
| rcu_read_lock(); |
| |
| perf_prepare_sample(&header, data, event, regs); |
| |
| if (perf_output_begin(&handle, event, header.size)) |
| goto exit; |
| |
| perf_output_sample(&handle, &header, data, event); |
| |
| perf_output_end(&handle); |
| |
| exit: |
| rcu_read_unlock(); |
| } |
| |
| /* |
| * read event_id |
| */ |
| |
| struct perf_read_event { |
| struct perf_event_header header; |
| |
| u32 pid; |
| u32 tid; |
| }; |
| |
| static void |
| perf_event_read_event(struct perf_event *event, |
| struct task_struct *task) |
| { |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| struct perf_read_event read_event = { |
| .header = { |
| .type = PERF_RECORD_READ, |
| .misc = 0, |
| .size = sizeof(read_event) + event->read_size, |
| }, |
| .pid = perf_event_pid(event, task), |
| .tid = perf_event_tid(event, task), |
| }; |
| int ret; |
| |
| perf_event_header__init_id(&read_event.header, &sample, event); |
| ret = perf_output_begin(&handle, event, read_event.header.size); |
| if (ret) |
| return; |
| |
| perf_output_put(&handle, read_event); |
| perf_output_read(&handle, event); |
| perf_event__output_id_sample(event, &handle, &sample); |
| |
| perf_output_end(&handle); |
| } |
| |
| typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data); |
| |
| static void |
| perf_event_aux_ctx(struct perf_event_context *ctx, |
| perf_event_aux_output_cb output, |
| void *data) |
| { |
| struct perf_event *event; |
| |
| list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
| if (event->state < PERF_EVENT_STATE_INACTIVE) |
| continue; |
| if (!event_filter_match(event)) |
| continue; |
| output(event, data); |
| } |
| } |
| |
| static void |
| perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data, |
| struct perf_event_context *task_ctx) |
| { |
| rcu_read_lock(); |
| preempt_disable(); |
| perf_event_aux_ctx(task_ctx, output, data); |
| preempt_enable(); |
| rcu_read_unlock(); |
| } |
| |
| static void |
| perf_event_aux(perf_event_aux_output_cb output, void *data, |
| struct perf_event_context *task_ctx) |
| { |
| struct perf_cpu_context *cpuctx; |
| struct perf_event_context *ctx; |
| struct pmu *pmu; |
| int ctxn; |
| |
| /* |
| * If we have task_ctx != NULL we only notify |
| * the task context itself. The task_ctx is set |
| * only for EXIT events before releasing task |
| * context. |
| */ |
| if (task_ctx) { |
| perf_event_aux_task_ctx(output, data, task_ctx); |
| return; |
| } |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(pmu, &pmus, entry) { |
| cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); |
| if (cpuctx->unique_pmu != pmu) |
| goto next; |
| perf_event_aux_ctx(&cpuctx->ctx, output, data); |
| ctxn = pmu->task_ctx_nr; |
| if (ctxn < 0) |
| goto next; |
| ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); |
| if (ctx) |
| perf_event_aux_ctx(ctx, output, data); |
| next: |
| put_cpu_ptr(pmu->pmu_cpu_context); |
| } |
| rcu_read_unlock(); |
| } |
| |
| /* |
| * task tracking -- fork/exit |
| * |
| * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task |
| */ |
| |
| struct perf_task_event { |
| struct task_struct *task; |
| struct perf_event_context *task_ctx; |
| |
| struct { |
| struct perf_event_header header; |
| |
| u32 pid; |
| u32 ppid; |
| u32 tid; |
| u32 ptid; |
| u64 time; |
| } event_id; |
| }; |
| |
| static int perf_event_task_match(struct perf_event *event) |
| { |
| return event->attr.comm || event->attr.mmap || |
| event->attr.mmap2 || event->attr.mmap_data || |
| event->attr.task; |
| } |
| |
| static void perf_event_task_output(struct perf_event *event, |
| void *data) |
| { |
| struct perf_task_event *task_event = data; |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| struct task_struct *task = task_event->task; |
| int ret, size = task_event->event_id.header.size; |
| |
| if (!perf_event_task_match(event)) |
| return; |
| |
| perf_event_header__init_id(&task_event->event_id.header, &sample, event); |
| |
| ret = perf_output_begin(&handle, event, |
| task_event->event_id.header.size); |
| if (ret) |
| goto out; |
| |
| task_event->event_id.pid = perf_event_pid(event, task); |
| task_event->event_id.ppid = perf_event_pid(event, current); |
| |
| task_event->event_id.tid = perf_event_tid(event, task); |
| task_event->event_id.ptid = perf_event_tid(event, current); |
| |
| task_event->event_id.time = perf_event_clock(event); |
| |
| perf_output_put(&handle, task_event->event_id); |
| |
| perf_event__output_id_sample(event, &handle, &sample); |
| |
| perf_output_end(&handle); |
| out: |
| task_event->event_id.header.size = size; |
| } |
| |
| static void perf_event_task(struct task_struct *task, |
| struct perf_event_context *task_ctx, |
| int new) |
| { |
| struct perf_task_event task_event; |
| |
| if (!atomic_read(&nr_comm_events) && |
| !atomic_read(&nr_mmap_events) && |
| !atomic_read(&nr_task_events)) |
| return; |
| |
| task_event = (struct perf_task_event){ |
| .task = task, |
| .task_ctx = task_ctx, |
| .event_id = { |
| .header = { |
| .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, |
| .misc = 0, |
| .size = sizeof(task_event.event_id), |
| }, |
| /* .pid */ |
| /* .ppid */ |
| /* .tid */ |
| /* .ptid */ |
| /* .time */ |
| }, |
| }; |
| |
| perf_event_aux(perf_event_task_output, |
| &task_event, |
| task_ctx); |
| } |
| |
| void perf_event_fork(struct task_struct *task) |
| { |
| perf_event_task(task, NULL, 1); |
| } |
| |
| /* |
| * comm tracking |
| */ |
| |
| struct perf_comm_event { |
| struct task_struct *task; |
| char *comm; |
| int comm_size; |
| |
| struct { |
| struct perf_event_header header; |
| |
| u32 pid; |
| u32 tid; |
| } event_id; |
| }; |
| |
| static int perf_event_comm_match(struct perf_event *event) |
| { |
| return event->attr.comm; |
| } |
| |
| static void perf_event_comm_output(struct perf_event *event, |
| void *data) |
| { |
| struct perf_comm_event *comm_event = data; |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| int size = comm_event->event_id.header.size; |
| int ret; |
| |
| if (!perf_event_comm_match(event)) |
| return; |
| |
| perf_event_header__init_id(&comm_event->event_id.header, &sample, event); |
| ret = perf_output_begin(&handle, event, |
| comm_event->event_id.header.size); |
| |
| if (ret) |
| goto out; |
| |
| comm_event->event_id.pid = perf_event_pid(event, comm_event->task); |
| comm_event->event_id.tid = perf_event_tid(event, comm_event->task); |
| |
| perf_output_put(&handle, comm_event->event_id); |
| __output_copy(&handle, comm_event->comm, |
| comm_event->comm_size); |
| |
| perf_event__output_id_sample(event, &handle, &sample); |
| |
| perf_output_end(&handle); |
| out: |
| comm_event->event_id.header.size = size; |
| } |
| |
| static void perf_event_comm_event(struct perf_comm_event *comm_event) |
| { |
| char comm[TASK_COMM_LEN]; |
| unsigned int size; |
| |
| memset(comm, 0, sizeof(comm)); |
| strlcpy(comm, comm_event->task->comm, sizeof(comm)); |
| size = ALIGN(strlen(comm)+1, sizeof(u64)); |
| |
| comm_event->comm = comm; |
| comm_event->comm_size = size; |
| |
| comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; |
| |
| perf_event_aux(perf_event_comm_output, |
| comm_event, |
| NULL); |
| } |
| |
| void perf_event_comm(struct task_struct *task, bool exec) |
| { |
| struct perf_comm_event comm_event; |
| |
| if (!atomic_read(&nr_comm_events)) |
| return; |
| |
| comm_event = (struct perf_comm_event){ |
| .task = task, |
| /* .comm */ |
| /* .comm_size */ |
| .event_id = { |
| .header = { |
| .type = PERF_RECORD_COMM, |
| .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, |
| /* .size */ |
| }, |
| /* .pid */ |
| /* .tid */ |
| }, |
| }; |
| |
| perf_event_comm_event(&comm_event); |
| } |
| |
| /* |
| * mmap tracking |
| */ |
| |
| struct perf_mmap_event { |
| struct vm_area_struct *vma; |
| |
| const char *file_name; |
| int file_size; |
| int maj, min; |
| u64 ino; |
| u64 ino_generation; |
| u32 prot, flags; |
| |
| struct { |
| struct perf_event_header header; |
| |
| u32 pid; |
| u32 tid; |
| u64 start; |
| u64 len; |
| u64 pgoff; |
| } event_id; |
| }; |
| |
| static int perf_event_mmap_match(struct perf_event *event, |
| void *data) |
| { |
| struct perf_mmap_event *mmap_event = data; |
| struct vm_area_struct *vma = mmap_event->vma; |
| int executable = vma->vm_flags & VM_EXEC; |
| |
| return (!executable && event->attr.mmap_data) || |
| (executable && (event->attr.mmap || event->attr.mmap2)); |
| } |
| |
| static void perf_event_mmap_output(struct perf_event *event, |
| void *data) |
| { |
| struct perf_mmap_event *mmap_event = data; |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| int size = mmap_event->event_id.header.size; |
| int ret; |
| |
| if (!perf_event_mmap_match(event, data)) |
| return; |
| |
| if (event->attr.mmap2) { |
| mmap_event->event_id.header.type = PERF_RECORD_MMAP2; |
| mmap_event->event_id.header.size += sizeof(mmap_event->maj); |
| mmap_event->event_id.header.size += sizeof(mmap_event->min); |
| mmap_event->event_id.header.size += sizeof(mmap_event->ino); |
| mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); |
| mmap_event->event_id.header.size += sizeof(mmap_event->prot); |
| mmap_event->event_id.header.size += sizeof(mmap_event->flags); |
| } |
| |
| perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); |
| ret = perf_output_begin(&handle, event, |
| mmap_event->event_id.header.size); |
| if (ret) |
| goto out; |
| |
| mmap_event->event_id.pid = perf_event_pid(event, current); |
| mmap_event->event_id.tid = perf_event_tid(event, current); |
| |
| perf_output_put(&handle, mmap_event->event_id); |
| |
| if (event->attr.mmap2) { |
| perf_output_put(&handle, mmap_event->maj); |
| perf_output_put(&handle, mmap_event->min); |
| perf_output_put(&handle, mmap_event->ino); |
| perf_output_put(&handle, mmap_event->ino_generation); |
| perf_output_put(&handle, mmap_event->prot); |
| perf_output_put(&handle, mmap_event->flags); |
| } |
| |
| __output_copy(&handle, mmap_event->file_name, |
| mmap_event->file_size); |
| |
| perf_event__output_id_sample(event, &handle, &sample); |
| |
| perf_output_end(&handle); |
| out: |
| mmap_event->event_id.header.size = size; |
| } |
| |
| static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) |
| { |
| struct vm_area_struct *vma = mmap_event->vma; |
| struct file *file = vma->vm_file; |
| int maj = 0, min = 0; |
| u64 ino = 0, gen = 0; |
| u32 prot = 0, flags = 0; |
| unsigned int size; |
| char tmp[16]; |
| char *buf = NULL; |
| char *name; |
| |
| if (file) { |
| struct inode *inode; |
| dev_t dev; |
| |
| buf = kmalloc(PATH_MAX, GFP_KERNEL); |
| if (!buf) { |
| name = "//enomem"; |
| goto cpy_name; |
| } |
| /* |
| * d_path() works from the end of the rb backwards, so we |
| * need to add enough zero bytes after the string to handle |
| * the 64bit alignment we do later. |
| */ |
| name = file_path(file, buf, PATH_MAX - sizeof(u64)); |
| if (IS_ERR(name)) { |
| name = "//toolong"; |
| goto cpy_name; |
| } |
| inode = file_inode(vma->vm_file); |
| dev = inode->i_sb->s_dev; |
| ino = inode->i_ino; |
| gen = inode->i_generation; |
| maj = MAJOR(dev); |
| min = MINOR(dev); |
| |
| if (vma->vm_flags & VM_READ) |
| prot |= PROT_READ; |
| if (vma->vm_flags & VM_WRITE) |
| prot |= PROT_WRITE; |
| if (vma->vm_flags & VM_EXEC) |
| prot |= PROT_EXEC; |
| |
| if (vma->vm_flags & VM_MAYSHARE) |
| flags = MAP_SHARED; |
| else |
| flags = MAP_PRIVATE; |
| |
| if (vma->vm_flags & VM_DENYWRITE) |
| flags |= MAP_DENYWRITE; |
| if (vma->vm_flags & VM_MAYEXEC) |
| flags |= MAP_EXECUTABLE; |
| if (vma->vm_flags & VM_LOCKED) |
| flags |= MAP_LOCKED; |
| if (vma->vm_flags & VM_HUGETLB) |
| flags |= MAP_HUGETLB; |
| |
| goto got_name; |
| } else { |
| if (vma->vm_ops && vma->vm_ops->name) { |
| name = (char *) vma->vm_ops->name(vma); |
| if (name) |
| goto cpy_name; |
| } |
| |
| name = (char *)arch_vma_name(vma); |
| if (name) |
| goto cpy_name; |
| |
| if (vma->vm_start <= vma->vm_mm->start_brk && |
| vma->vm_end >= vma->vm_mm->brk) { |
| name = "[heap]"; |
| goto cpy_name; |
| } |
| if (vma->vm_start <= vma->vm_mm->start_stack && |
| vma->vm_end >= vma->vm_mm->start_stack) { |
| name = "[stack]"; |
| goto cpy_name; |
| } |
| |
| name = "//anon"; |
| goto cpy_name; |
| } |
| |
| cpy_name: |
| strlcpy(tmp, name, sizeof(tmp)); |
| name = tmp; |
| got_name: |
| /* |
| * Since our buffer works in 8 byte units we need to align our string |
| * size to a multiple of 8. However, we must guarantee the tail end is |
| * zero'd out to avoid leaking random bits to userspace. |
| */ |
| size = strlen(name)+1; |
| while (!IS_ALIGNED(size, sizeof(u64))) |
| name[size++] = '\0'; |
| |
| mmap_event->file_name = name; |
| mmap_event->file_size = size; |
| mmap_event->maj = maj; |
| mmap_event->min = min; |
| mmap_event->ino = ino; |
| mmap_event->ino_generation = gen; |
| mmap_event->prot = prot; |
| mmap_event->flags = flags; |
| |
| if (!(vma->vm_flags & VM_EXEC)) |
| mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; |
| |
| mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; |
| |
| perf_event_aux(perf_event_mmap_output, |
| mmap_event, |
| NULL); |
| |
| kfree(buf); |
| } |
| |
| void perf_event_mmap(struct vm_area_struct *vma) |
| { |
| struct perf_mmap_event mmap_event; |
| |
| if (!atomic_read(&nr_mmap_events)) |
| return; |
| |
| mmap_event = (struct perf_mmap_event){ |
| .vma = vma, |
| /* .file_name */ |
| /* .file_size */ |
| .event_id = { |
| .header = { |
| .type = PERF_RECORD_MMAP, |
| .misc = PERF_RECORD_MISC_USER, |
| /* .size */ |
| }, |
| /* .pid */ |
| /* .tid */ |
| .start = vma->vm_start, |
| .len = vma->vm_end - vma->vm_start, |
| .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, |
| }, |
| /* .maj (attr_mmap2 only) */ |
| /* .min (attr_mmap2 only) */ |
| /* .ino (attr_mmap2 only) */ |
| /* .ino_generation (attr_mmap2 only) */ |
| /* .prot (attr_mmap2 only) */ |
| /* .flags (attr_mmap2 only) */ |
| }; |
| |
| perf_event_mmap_event(&mmap_event); |
| } |
| |
| void perf_event_aux_event(struct perf_event *event, unsigned long head, |
| unsigned long size, u64 flags) |
| { |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| struct perf_aux_event { |
| struct perf_event_header header; |
| u64 offset; |
| u64 size; |
| u64 flags; |
| } rec = { |
| .header = { |
| .type = PERF_RECORD_AUX, |
| .misc = 0, |
| .size = sizeof(rec), |
| }, |
| .offset = head, |
| .size = size, |
| .flags = flags, |
| }; |
| int ret; |
| |
| perf_event_header__init_id(&rec.header, &sample, event); |
| ret = perf_output_begin(&handle, event, rec.header.size); |
| |
| if (ret) |
| return; |
| |
| perf_output_put(&handle, rec); |
| perf_event__output_id_sample(event, &handle, &sample); |
| |
| perf_output_end(&handle); |
| } |
| |
| /* |
| * Lost/dropped samples logging |
| */ |
| void perf_log_lost_samples(struct perf_event *event, u64 lost) |
| { |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| int ret; |
| |
| struct { |
| struct perf_event_header header; |
| u64 lost; |
| } lost_samples_event = { |
| .header = { |
| .type = PERF_RECORD_LOST_SAMPLES, |
| .misc = 0, |
| .size = sizeof(lost_samples_event), |
| }, |
| .lost = lost, |
| }; |
| |
| perf_event_header__init_id(&lost_samples_event.header, &sample, event); |
| |
| ret = perf_output_begin(&handle, event, |
| lost_samples_event.header.size); |
| if (ret) |
| return; |
| |
| perf_output_put(&handle, lost_samples_event); |
| perf_event__output_id_sample(event, &handle, &sample); |
| perf_output_end(&handle); |
| } |
| |
| /* |
| * context_switch tracking |
| */ |
| |
| struct perf_switch_event { |
| struct task_struct *task; |
| struct task_struct *next_prev; |
| |
| struct { |
| struct perf_event_header header; |
| u32 next_prev_pid; |
| u32 next_prev_tid; |
| } event_id; |
| }; |
| |
| static int perf_event_switch_match(struct perf_event *event) |
| { |
| return event->attr.context_switch; |
| } |
| |
| static void perf_event_switch_output(struct perf_event *event, void *data) |
| { |
| struct perf_switch_event *se = data; |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| int ret; |
| |
| if (!perf_event_switch_match(event)) |
| return; |
| |
| /* Only CPU-wide events are allowed to see next/prev pid/tid */ |
| if (event->ctx->task) { |
| se->event_id.header.type = PERF_RECORD_SWITCH; |
| se->event_id.header.size = sizeof(se->event_id.header); |
| } else { |
| se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; |
| se->event_id.header.size = sizeof(se->event_id); |
| se->event_id.next_prev_pid = |
| perf_event_pid(event, se->next_prev); |
| se->event_id.next_prev_tid = |
| perf_event_tid(event, se->next_prev); |
| } |
| |
| perf_event_header__init_id(&se->event_id.header, &sample, event); |
| |
| ret = perf_output_begin(&handle, event, se->event_id.header.size); |
| if (ret) |
| return; |
| |
| if (event->ctx->task) |
| perf_output_put(&handle, se->event_id.header); |
| else |
| perf_output_put(&handle, se->event_id); |
| |
| perf_event__output_id_sample(event, &handle, &sample); |
| |
| perf_output_end(&handle); |
| } |
| |
| static void perf_event_switch(struct task_struct *task, |
| struct task_struct *next_prev, bool sched_in) |
| { |
| struct perf_switch_event switch_event; |
| |
| /* N.B. caller checks nr_switch_events != 0 */ |
| |
| switch_event = (struct perf_switch_event){ |
| .task = task, |
| .next_prev = next_prev, |
| .event_id = { |
| .header = { |
| /* .type */ |
| .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, |
| /* .size */ |
| }, |
| /* .next_prev_pid */ |
| /* .next_prev_tid */ |
| }, |
| }; |
| |
| perf_event_aux(perf_event_switch_output, |
| &switch_event, |
| NULL); |
| } |
| |
| /* |
| * IRQ throttle logging |
| */ |
| |
| static void perf_log_throttle(struct perf_event *event, int enable) |
| { |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| int ret; |
| |
| struct { |
| struct perf_event_header header; |
| u64 time; |
| u64 id; |
| u64 stream_id; |
| } throttle_event = { |
| .header = { |
| .type = PERF_RECORD_THROTTLE, |
| .misc = 0, |
| .size = sizeof(throttle_event), |
| }, |
| .time = perf_event_clock(event), |
| .id = primary_event_id(event), |
| .stream_id = event->id, |
| }; |
| |
| if (enable) |
| throttle_event.header.type = PERF_RECORD_UNTHROTTLE; |
| |
| perf_event_header__init_id(&throttle_event.header, &sample, event); |
| |
| ret = perf_output_begin(&handle, event, |
| throttle_event.header.size); |
| if (ret) |
| return; |
| |
| perf_output_put(&handle, throttle_event); |
| perf_event__output_id_sample(event, &handle, &sample); |
| perf_output_end(&handle); |
| } |
| |
| static void perf_log_itrace_start(struct perf_event *event) |
| { |
| struct perf_output_handle handle; |
| struct perf_sample_data sample; |
| struct perf_aux_event { |
| struct perf_event_header header; |
| u32 pid; |
| u32 tid; |
| } rec; |
| int ret; |
| |
| if (event->parent) |
| event = event->parent; |
| |
| if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || |
| event->hw.itrace_started) |
| return; |
| |
| rec.header.type = PERF_RECORD_ITRACE_START; |
| rec.header.misc = 0; |
| rec.header.size = sizeof(rec); |
| rec.pid = perf_event_pid(event, current); |
| rec.tid = perf_event_tid(event, current); |
| |
| perf_event_header__init_id(&rec.header, &sample, event); |
| ret = perf_output_begin(&handle, event, rec.header.size); |
| |
| if (ret) |
| return; |
| |
| perf_output_put(&handle, rec); |
| perf_event__output_id_sample(event, &handle, &sample); |
| |
| perf_output_end(&handle); |
| } |
| |
| /* |
| * Generic event overflow handling, sampling. |
| */ |
| |
| static int __perf_event_overflow(struct perf_event *event, |
| int throttle, struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| int events = atomic_read(&event->event_limit); |
| struct hw_perf_event *hwc = &event->hw; |
| u64 seq; |
| int ret = 0; |
| |
| /* |
| * Non-sampling counters might still use the PMI to fold short |
| * hardware counters, ignore those. |
| */ |
| if (unlikely(!is_sampling_event(event))) |
| return 0; |
| |
| seq = __this_cpu_read(perf_throttled_seq); |
| if (seq != hwc->interrupts_seq) { |
| hwc->interrupts_seq = seq; |
| hwc->interrupts = 1; |
| } else { |
| hwc->interrupts++; |
| if (unlikely(throttle |
| && hwc->interrupts >= max_samples_per_tick)) { |
| __this_cpu_inc(perf_throttled_count); |
| tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); |
| hwc->interrupts = MAX_INTERRUPTS; |
| perf_log_throttle(event, 0); |
| ret = 1; |
| } |
| } |
| |
| if (event->attr.freq) { |
| u64 now = perf_clock(); |
| s64 delta = now - hwc->freq_time_stamp; |
| |
| hwc->freq_time_stamp = now; |
| |
| if (delta > 0 && delta < 2*TICK_NSEC) |
| perf_adjust_period(event, delta, hwc->last_period, true); |
| } |
| |
| /* |
| * XXX event_limit might not quite work as expected on inherited |
| * events |
| */ |
| |
| event->pending_kill = POLL_IN; |
| if (events && atomic_dec_and_test(&event->event_limit)) { |
| ret = 1; |
| event->pending_kill = POLL_HUP; |
| event->pending_disable = 1; |
| irq_work_queue(&event->pending); |
| } |
| |
| if (event->overflow_handler) |
| event->overflow_handler(event, data, regs); |
| else |
| perf_event_output(event, data, regs); |
| |
| if (*perf_event_fasync(event) && event->pending_kill) { |
| event->pending_wakeup = 1; |
| irq_work_queue(&event->pending); |
| } |
| |
| return ret; |
| } |
| |
| int perf_event_overflow(struct perf_event *event, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| return __perf_event_overflow(event, 1, data, regs); |
| } |
| |
| /* |
| * Generic software event infrastructure |
| */ |
| |
| struct swevent_htable { |
| struct swevent_hlist *swevent_hlist; |
| struct mutex hlist_mutex; |
| int hlist_refcount; |
| |
| /* Recursion avoidance in each contexts */ |
| int recursion[PERF_NR_CONTEXTS]; |
| }; |
| |
| static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); |
| |
| /* |
| * We directly increment event->count and keep a second value in |
| * event->hw.period_left to count intervals. This period event |
| * is kept in the range [-sample_period, 0] so that we can use the |
| * sign as trigger. |
| */ |
| |
| u64 perf_swevent_set_period(struct perf_event *event) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| u64 period = hwc->last_period; |
| u64 nr, offset; |
| s64 old, val; |
| |
| hwc->last_period = hwc->sample_period; |
| |
| again: |
| old = val = local64_read(&hwc->period_left); |
| if (val < 0) |
| return 0; |
| |
| nr = div64_u64(period + val, period); |
| offset = nr * period; |
| val -= offset; |
| if (local64_cmpxchg(&hwc->period_left, old, val) != old) |
| goto again; |
| |
| return nr; |
| } |
| |
| static void perf_swevent_overflow(struct perf_event *event, u64 overflow, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| int throttle = 0; |
| |
| if (!overflow) |
| overflow = perf_swevent_set_period(event); |
| |
| if (hwc->interrupts == MAX_INTERRUPTS) |
| return; |
| |
| for (; overflow; overflow--) { |
| if (__perf_event_overflow(event, throttle, |
| data, regs)) { |
| /* |
| * We inhibit the overflow from happening when |
| * hwc->interrupts == MAX_INTERRUPTS. |
| */ |
| break; |
| } |
| throttle = 1; |
| } |
| } |
| |
| static void perf_swevent_event(struct perf_event *event, u64 nr, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| |
| local64_add(nr, &event->count); |
| |
| if (!regs) |
| return; |
| |
| if (!is_sampling_event(event)) |
| return; |
| |
| if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { |
| data->period = nr; |
| return perf_swevent_overflow(event, 1, data, regs); |
| } else |
| data->period = event->hw.last_period; |
| |
| if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) |
| return perf_swevent_overflow(event, 1, data, regs); |
| |
| if (local64_add_negative(nr, &hwc->period_left)) |
| return; |
| |
| perf_swevent_overflow(event, 0, data, regs); |
| } |
| |
| static int perf_exclude_event(struct perf_event *event, |
| struct pt_regs *regs) |
| { |
| if (event->hw.state & PERF_HES_STOPPED) |
| return 1; |
| |
| if (regs) { |
| if (event->attr.exclude_user && user_mode(regs)) |
| return 1; |
| |
| if (event->attr.exclude_kernel && !user_mode(regs)) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static int perf_swevent_match(struct perf_event *event, |
| enum perf_type_id type, |
| u32 event_id, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| if (event->attr.type != type) |
| return 0; |
| |
| if (event->attr.config != event_id) |
| return 0; |
| |
| if (perf_exclude_event(event, regs)) |
| return 0; |
| |
| return 1; |
| } |
| |
| static inline u64 swevent_hash(u64 type, u32 event_id) |
| { |
| u64 val = event_id | (type << 32); |
| |
| return hash_64(val, SWEVENT_HLIST_BITS); |
| } |
| |
| static inline struct hlist_head * |
| __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) |
| { |
| u64 hash = swevent_hash(type, event_id); |
| |
| return &hlist->heads[hash]; |
| } |
| |
| /* For the read side: events when they trigger */ |
| static inline struct hlist_head * |
| find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) |
| { |
| struct swevent_hlist *hlist; |
| |
| hlist = rcu_dereference(swhash->swevent_hlist); |
| if (!hlist) |
| return NULL; |
| |
| return __find_swevent_head(hlist, type, event_id); |
| } |
| |
| /* For the event head insertion and removal in the hlist */ |
| static inline struct hlist_head * |
| find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) |
| { |
| struct swevent_hlist *hlist; |
| u32 event_id = event->attr.config; |
| u64 type = event->attr.type; |
| |
| /* |
| * Event scheduling is always serialized against hlist allocation |
| * and release. Which makes the protected version suitable here. |
| * The context lock guarantees that. |
| */ |
| hlist = rcu_dereference_protected(swhash->swevent_hlist, |
| lockdep_is_held(&event->ctx->lock)); |
| if (!hlist) |
| return NULL; |
| |
| return __find_swevent_head(hlist, type, event_id); |
| } |
| |
| static void do_perf_sw_event(enum perf_type_id type, u32 event_id, |
| u64 nr, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); |
| struct perf_event *event; |
| struct hlist_head *head; |
| |
| rcu_read_lock(); |
| head = find_swevent_head_rcu(swhash, type, event_id); |
| if (!head) |
| goto end; |
| |
| hlist_for_each_entry_rcu(event, head, hlist_entry) { |
| if (perf_swevent_match(event, type, event_id, data, regs)) |
| perf_swevent_event(event, nr, data, regs); |
| } |
| end: |
| rcu_read_unlock(); |
| } |
| |
| DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); |
| |
| int perf_swevent_get_recursion_context(void) |
| { |
| struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); |
| |
| return get_recursion_context(swhash->recursion); |
| } |
| EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); |
| |
| inline void perf_swevent_put_recursion_context(int rctx) |
| { |
| struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); |
| |
| put_recursion_context(swhash->recursion, rctx); |
| } |
| |
| void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) |
| { |
| struct perf_sample_data data; |
| |
| if (WARN_ON_ONCE(!regs)) |
| return; |
| |
| perf_sample_data_init(&data, addr, 0); |
| do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); |
| } |
| |
| void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) |
| { |
| int rctx; |
| |
| preempt_disable_notrace(); |
| rctx = perf_swevent_get_recursion_context(); |
| if (unlikely(rctx < 0)) |
| goto fail; |
| |
| ___perf_sw_event(event_id, nr, regs, addr); |
| |
| perf_swevent_put_recursion_context(rctx); |
| fail: |
| preempt_enable_notrace(); |
| } |
| |
| static void perf_swevent_read(struct perf_event *event) |
| { |
| } |
| |
| static int perf_swevent_add(struct perf_event *event, int flags) |
| { |
| struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); |
| struct hw_perf_event *hwc = &event->hw; |
| struct hlist_head *head; |
| |
| if (is_sampling_event(event)) { |
| hwc->last_period = hwc->sample_period; |
| perf_swevent_set_period(event); |
| } |
| |
| hwc->state = !(flags & PERF_EF_START); |
| |
| head = find_swevent_head(swhash, event); |
| if (WARN_ON_ONCE(!head)) |
| return -EINVAL; |
| |
| hlist_add_head_rcu(&event->hlist_entry, head); |
| perf_event_update_userpage(event); |
| |
| return 0; |
| } |
| |
| static void perf_swevent_del(struct perf_event *event, int flags) |
| { |
| hlist_del_rcu(&event->hlist_entry); |
| } |
| |
| static void perf_swevent_start(struct perf_event *event, int flags) |
| { |
| event->hw.state = 0; |
| } |
| |
| static void perf_swevent_stop(struct perf_event *event, int flags) |
| { |
| event->hw.state = PERF_HES_STOPPED; |
| } |
| |
| /* Deref the hlist from the update side */ |
| static inline struct swevent_hlist * |
| swevent_hlist_deref(struct swevent_htable *swhash) |
| { |
| return rcu_dereference_protected(swhash->swevent_hlist, |
| lockdep_is_held(&swhash->hlist_mutex)); |
| } |
| |
| static void swevent_hlist_release(struct swevent_htable *swhash) |
| { |
| struct swevent_hlist *hlist = swevent_hlist_deref(swhash); |
| |
| if (!hlist) |
| return; |
| |
| RCU_INIT_POINTER(swhash->swevent_hlist, NULL); |
| kfree_rcu(hlist, rcu_head); |
| } |
| |
| static void swevent_hlist_put_cpu(int cpu) |
| { |
| struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); |
| |
| mutex_lock(&swhash->hlist_mutex); |
| |
| if (!--swhash->hlist_refcount) |
| swevent_hlist_release(swhash); |
| |
| mutex_unlock(&swhash->hlist_mutex); |
| } |
| |
| static void swevent_hlist_put(void) |
| { |
| int cpu; |
| |
| for_each_possible_cpu(cpu) |
| swevent_hlist_put_cpu(cpu); |
| } |
| |
| static int swevent_hlist_get_cpu(int cpu) |
| { |
| struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); |
| int err = 0; |
| |
| mutex_lock(&swhash->hlist_mutex); |
| if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { |
| struct swevent_hlist *hlist; |
| |
| hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); |
| if (!hlist) { |
| err = -ENOMEM; |
| goto exit; |
| } |
| rcu_assign_pointer(swhash->swevent_hlist, hlist); |
| } |
| swhash->hlist_refcount++; |
| exit: |
| mutex_unlock(&swhash->hlist_mutex); |
| |
| return err; |
| } |
| |
| static int swevent_hlist_get(void) |
| { |
| int err, cpu, failed_cpu; |
| |
| get_online_cpus(); |
| for_each_possible_cpu(cpu) { |
| err = swevent_hlist_get_cpu(cpu); |
| if (err) { |
| failed_cpu = cpu; |
| goto fail; |
| } |
| } |
| put_online_cpus(); |
| |
| return 0; |
| fail: |
| for_each_possible_cpu(cpu) { |
| if (cpu == failed_cpu) |
| break; |
| swevent_hlist_put_cpu(cpu); |
| } |
| |
| put_online_cpus(); |
| return err; |
| } |
| |
| struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; |
| |
| static void sw_perf_event_destroy(struct perf_event *event) |
| { |
| u64 event_id = event->attr.config; |
| |
| WARN_ON(event->parent); |
| |
| static_key_slow_dec(&perf_swevent_enabled[event_id]); |
| swevent_hlist_put(); |
| } |
| |
| static int perf_swevent_init(struct perf_event *event) |
| { |
| u64 event_id = event->attr.config; |
| |
| if (event->attr.type != PERF_TYPE_SOFTWARE) |
| return -ENOENT; |
| |
| /* |
| * no branch sampling for software events |
| */ |
| if (has_branch_stack(event)) |
| return -EOPNOTSUPP; |
| |
| switch (event_id) { |
| case PERF_COUNT_SW_CPU_CLOCK: |
| case PERF_COUNT_SW_TASK_CLOCK: |
| return -ENOENT; |
| |
| default: |
| break; |
| } |
| |
| if (event_id >= PERF_COUNT_SW_MAX) |
| return -ENOENT; |
| |
| if (!event->parent) { |
| int err; |
| |
| err = swevent_hlist_get(); |
| if (err) |
| return err; |
| |
| static_key_slow_inc(&perf_swevent_enabled[event_id]); |
| event->destroy = sw_perf_event_destroy; |
| } |
| |
| return 0; |
| } |
| |
| static struct pmu perf_swevent = { |
| .task_ctx_nr = perf_sw_context, |
| |
| .capabilities = PERF_PMU_CAP_NO_NMI, |
| |
| .event_init = perf_swevent_init, |
| .add = perf_swevent_add, |
| .del = perf_swevent_del, |
| .start = perf_swevent_start, |
| .stop = perf_swevent_stop, |
| .read = perf_swevent_read, |
| }; |
| |
| #ifdef CONFIG_EVENT_TRACING |
| |
| static int perf_tp_filter_match(struct perf_event *event, |
| struct perf_sample_data *data) |
| { |
| void *record = data->raw->data; |
| |
| /* only top level events have filters set */ |
| if (event->parent) |
| event = event->parent; |
| |
| if (likely(!event->filter) || filter_match_preds(event->filter, record)) |
| return 1; |
| return 0; |
| } |
| |
| static int perf_tp_event_match(struct perf_event *event, |
| struct perf_sample_data *data, |
| struct pt_regs *regs) |
| { |
| if (event->hw.state & PERF_HES_STOPPED) |
| return 0; |
| /* |
| * All tracepoints are from kernel-space. |
| */ |
| if (event->attr.exclude_kernel) |
| return 0; |
| |
| if (!perf_tp_filter_match(event, data)) |
| return 0; |
| |
| return 1; |
| } |
| |
| void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, |
| struct pt_regs *regs, struct hlist_head *head, int rctx, |
| struct task_struct *task) |
| { |
| struct perf_sample_data data; |
| struct perf_event *event; |
| |
| struct perf_raw_record raw = { |
| .size = entry_size, |
| .data = record, |
| }; |
| |
| perf_sample_data_init(&data, addr, 0); |
| data.raw = &raw; |
| |
| hlist_for_each_entry_rcu(event, head, hlist_entry) { |
| if (perf_tp_event_match(event, &data, regs)) |
| perf_swevent_event(event, count, &data, regs); |
| } |
| |
| /* |
| * If we got specified a target task, also iterate its context and |
| * deliver this event there too. |
| */ |
| if (task && task != current) { |
| struct perf_event_context *ctx; |
| struct trace_entry *entry = record; |
| |
| rcu_read_lock(); |
| ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); |
| if (!ctx) |
| goto unlock; |
| |
| list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
| if (event->attr.type != PERF_TYPE_TRACEPOINT) |
| continue; |
| if (event->attr.config != entry->type) |
| continue; |
| if (perf_tp_event_match(event, &data, regs)) |
| perf_swevent_event(event, count, &data, regs); |
| } |
| unlock: |
| rcu_read_unlock(); |
| } |
| |
| perf_swevent_put_recursion_context(rctx); |
| } |
| EXPORT_SYMBOL_GPL(perf_tp_event); |
| |
| static void tp_perf_event_destroy(struct perf_event *event) |
| { |
| perf_trace_destroy(event); |
| } |
| |
| static int perf_tp_event_init(struct perf_event *event) |
| { |
| int err; |
| |
| if (event->attr.type != PERF_TYPE_TRACEPOINT) |
| return -ENOENT; |
| |
| /* |
| * no branch sampling for tracepoint events |
| */ |
| if (has_branch_stack(event)) |
| return -EOPNOTSUPP; |
| |
| err = perf_trace_init(event); |
| if (err) |
| return err; |
| |
| event->destroy = tp_perf_event_destroy; |
| |
| return 0; |
| } |
| |
| static struct pmu perf_tracepoint = { |
| .task_ctx_nr = perf_sw_context, |
| |
| .event_init = perf_tp_event_init, |
| .add = perf_trace_add, |
| .del = perf_trace_del, |
| .start = perf_swevent_start, |
| .stop = perf_swevent_stop, |
| .read = perf_swevent_read, |
| }; |
| |
| static inline void perf_tp_register(void) |
| { |
| perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); |
| } |
| |
| static int perf_event_set_filter(struct perf_event *event, void __user *arg) |
| { |
| char *filter_str; |
| int ret; |
| |
| if (event->attr.type != PERF_TYPE_TRACEPOINT) |
| return -EINVAL; |
| |
| filter_str = strndup_user(arg, PAGE_SIZE); |
| if (IS_ERR(filter_str)) |
| return PTR_ERR(filter_str); |
| |
| ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); |
| |
| kfree(filter_str); |
| return ret; |
| } |
| |
| static void perf_event_free_filter(struct perf_event *event) |
| { |
| ftrace_profile_free_filter(event); |
| } |
| |
| static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) |
| { |
| struct bpf_prog *prog; |
| |
| if (event->attr.type != PERF_TYPE_TRACEPOINT) |
| return -EINVAL; |
| |
| if (event->tp_event->prog) |
| return -EEXIST; |
| |
| if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE)) |
| /* bpf programs can only be attached to u/kprobes */ |
| return -EINVAL; |
| |
| prog = bpf_prog_get(prog_fd); |
| if (IS_ERR(prog)) |
| return PTR_ERR(prog); |
| |
| if (prog->type != BPF_PROG_TYPE_KPROBE) { |
| /* valid fd, but invalid bpf program type */ |
| bpf_prog_put(prog); |
| return -EINVAL; |
| } |
| |
| event->tp_event->prog = prog; |
| |
| return 0; |
| } |
| |
| static void perf_event_free_bpf_prog(struct perf_event *event) |
| { |
| struct bpf_prog *prog; |
| |
| if (!event->tp_event) |
| return; |
| |
| prog = event->tp_event->prog; |
| if (prog) { |
| event->tp_event->prog = NULL; |
| bpf_prog_put(prog); |
| } |
| } |
| |
| #else |
| |
| static inline void perf_tp_register(void) |
| { |
| } |
| |
| static int perf_event_set_filter(struct perf_event *event, void __user *arg) |
| { |
| return -ENOENT; |
| } |
| |
| static void perf_event_free_filter(struct perf_event *event) |
| { |
| } |
| |
| static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) |
| { |
| return -ENOENT; |
| } |
| |
| static void perf_event_free_bpf_prog(struct perf_event *event) |
| { |
| } |
| #endif /* CONFIG_EVENT_TRACING */ |
| |
| #ifdef CONFIG_HAVE_HW_BREAKPOINT |
| void perf_bp_event(struct perf_event *bp, void *data) |
| { |
| struct perf_sample_data sample; |
| struct pt_regs *regs = data; |
| |
| perf_sample_data_init(&sample, bp->attr.bp_addr, 0); |
| |
| if (!bp->hw.state && !perf_exclude_event(bp, regs)) |
| perf_swevent_event(bp, 1, &sample, regs); |
| } |
| #endif |
| |
| /* |
| * hrtimer based swevent callback |
| */ |
| |
| static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) |
| { |
| enum hrtimer_restart ret = HRTIMER_RESTART; |
| struct perf_sample_data data; |
| struct pt_regs *regs; |
| struct perf_event *event; |
| u64 period; |
| |
| event = container_of(hrtimer, struct perf_event, hw.hrtimer); |
| |
| if (event->state != PERF_EVENT_STATE_ACTIVE) |
| return HRTIMER_NORESTART; |
| |
| event->pmu->read(event); |
| |
| perf_sample_data_init(&data, 0, event->hw.last_period); |
| regs = get_irq_regs(); |
| |
| if (regs && !perf_exclude_event(event, regs)) { |
| if (!(event->attr.exclude_idle && is_idle_task(current))) |
| if (__perf_event_overflow(event, 1, &data, regs)) |
| ret = HRTIMER_NORESTART; |
| } |
| |
| period = max_t(u64, 10000, event->hw.sample_period); |
| hrtimer_forward_now(hrtimer, ns_to_ktime(period)); |
| |
| return ret; |
| } |
| |
| static void perf_swevent_start_hrtimer(struct perf_event *event) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| s64 period; |
| |
| if (!is_sampling_event(event)) |
| return; |
| |
| period = local64_read(&hwc->period_left); |
| if (period) { |
| if (period < 0) |
| period = 10000; |
| |
| local64_set(&hwc->period_left, 0); |
| } else { |
| period = max_t(u64, 10000, hwc->sample_period); |
| } |
| hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), |
| HRTIMER_MODE_REL_PINNED); |
| } |
| |
| static void perf_swevent_cancel_hrtimer(struct perf_event *event) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| |
| if (is_sampling_event(event)) { |
| ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); |
| local64_set(&hwc->period_left, ktime_to_ns(remaining)); |
| |
| hrtimer_cancel(&hwc->hrtimer); |
| } |
| } |
| |
| static void perf_swevent_init_hrtimer(struct perf_event *event) |
| { |
| struct hw_perf_event *hwc = &event->hw; |
| |
| if (!is_sampling_event(event)) |
| return; |
| |
| hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| hwc->hrtimer.function = perf_swevent_hrtimer; |
| |
| /* |
| * Since hrtimers have a fixed rate, we can do a static freq->period |
| * mapping and avoid the whole period adjust feedback stuff. |
| */ |
| if (event->attr.freq) { |
| long freq = event->attr.sample_freq; |
| |
| event->attr.sample_period = NSEC_PER_SEC / freq; |
| hwc->sample_period = event->attr.sample_period; |
| local64_set(&hwc->period_left, hwc->sample_period); |
| hwc->last_period = hwc->sample_period; |
| event->attr.freq = 0; |
| } |
| } |
| |
| /* |
| * Software event: cpu wall time clock |
| */ |
| |
| static void cpu_clock_event_update(struct perf_event *event) |
| { |
| s64 prev; |
| u64 now; |
| |
| now = local_clock(); |
| prev = local64_xchg(&event->hw.prev_count, now); |
| local64_add(now - prev, &event->count); |
| } |
| |
| static void cpu_clock_event_start(struct perf_event *event, int flags) |
| { |
| local64_set(&event->hw.prev_count, local_clock()); |
| perf_swevent_start_hrtimer(event); |
| } |
| |
| static void cpu_clock_event_stop(struct perf_event *event, int flags) |
| { |
| perf_swevent_cancel_hrtimer(event); |
| cpu_clock_event_update(event); |
| } |
| |
| static int cpu_clock_event_add(struct perf_event *event, int flags) |
| { |
| if (flags & PERF_EF_START) |
| cpu_clock_event_start(event, flags); |
| perf_event_update_userpage(event); |
| |
| return 0; |
| } |
| |
| static void cpu_clock_event_del(struct perf_event *event, int flags) |
| { |
| cpu_clock_event_stop(event, flags); |
| } |
| |
| static void cpu_clock_event_read(struct perf_event *event) |
| { |
| cpu_clock_event_update(event); |
| } |
| |
| static int cpu_clock_event_init(struct perf_event *event) |
| { |
| if (event->attr.type != PERF_TYPE_SOFTWARE) |
| return -ENOENT; |
| |
| if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) |
| return -ENOENT; |
| |
| /* |
| * no branch sampling for software events |
| */ |
| if (has_branch_stack(event)) |
| return -EOPNOTSUPP; |
| |
| perf_swevent_init_hrtimer(event); |
| |
| return 0; |
| } |
| |
| static struct pmu perf_cpu_clock = { |
| .task_ctx_nr = perf_sw_context, |
| |
| .capabilities = PERF_PMU_CAP_NO_NMI, |
| |
| .event_init = cpu_clock_event_init, |
| .add = cpu_clock_event_add, |
| .del = cpu_clock_event_del, |
| .start = cpu_clock_event_start, |
| .stop = cpu_clock_event_stop, |
| .read = cpu_clock_event_read, |
| }; |
| |
| /* |
| * Software event: task time clock |
| */ |
| |
| static void task_clock_event_update(struct perf_event *event, u64 now) |
| { |
| u64 prev; |
| s64 delta; |
| |
| prev = local64_xchg(&event->hw.prev_count, now); |
| delta = now - prev; |
| local64_add(delta, &event->count); |
| } |
| |
| static void task_clock_event_start(struct perf_event *event, int flags) |
| { |
| local64_set(&event->hw.prev_count, event->ctx->time); |
| perf_swevent_start_hrtimer(event); |
| } |
| |
| static void task_clock_event_stop(struct perf_event *event, int flags) |
| { |
| perf_swevent_cancel_hrtimer(event); |
| task_clock_event_update(event, event->ctx->time); |
| } |
| |
| static int task_clock_event_add(struct perf_event *event, int flags) |
| { |
| if (flags & PERF_EF_START) |
| task_clock_event_start(event, flags); |
| perf_event_update_userpage(event); |
| |
| return 0; |
| } |
| |
| static void task_clock_event_del(struct perf_event *event, int flags) |
| { |
| task_clock_event_stop(event, PERF_EF_UPDATE); |
| } |
| |
| static void task_clock_event_read(struct perf_event *event) |
| { |
| u64 now = perf_clock(); |
| u64 delta = now - event->ctx->timestamp; |
| u64 time = event->ctx->time + delta; |
| |
| task_clock_event_update(event, time); |
| } |
| |
| static int task_clock_event_init(struct perf_event *event) |
| { |
| if (event->attr.type != PERF_TYPE_SOFTWARE) |
| return -ENOENT; |
| |
| if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) |
| return -ENOENT; |
| |
| /* |
| * no branch sampling for software events |
| */ |
| if (has_branch_stack(event)) |
| return -EOPNOTSUPP; |
| |
| perf_swevent_init_hrtimer(event); |
| |
| return 0; |
| } |
| |
| static struct pmu perf_task_clock = { |
| .task_ctx_nr = perf_sw_context, |
| |
| .capabilities = PERF_PMU_CAP_NO_NMI, |
| |
| .event_init = task_clock_event_init, |
| .add = task_clock_event_add, |
| .del = task_clock_event_del, |
| .start = task_clock_event_start, |
| .stop = task_clock_event_stop, |
| .read = task_clock_event_read, |
| }; |
| |
| static void perf_pmu_nop_void(struct pmu *pmu) |
| { |
| } |
| |
| static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) |
| { |
| } |
| |
| static int perf_pmu_nop_int(struct pmu *pmu) |
| { |
| return 0; |
| } |
| |
| static DEFINE_PER_CPU(unsigned int, nop_txn_flags); |
| |
| static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) |
| { |
| __this_cpu_write(nop_txn_flags, flags); |
| |
| if (flags & ~PERF_PMU_TXN_ADD) |
| return; |
| |
| perf_pmu_disable(pmu); |
| } |
| |
| static int perf_pmu_commit_txn(struct pmu *pmu) |
| { |
| unsigned int flags = __this_cpu_read(nop_txn_flags); |
| |
| __this_cpu_write(nop_txn_flags, 0); |
| |
| if (flags & ~PERF_PMU_TXN_ADD) |
| return 0; |
| |
| perf_pmu_enable(pmu); |
| return 0; |
| } |
| |
| static void perf_pmu_cancel_txn(struct pmu *pmu) |
| { |
| unsigned int flags = __this_cpu_read(nop_txn_flags); |
| |
| __this_cpu_write(nop_txn_flags, 0); |
| |
| if (flags & ~PERF_PMU_TXN_ADD) |
| return; |
| |
| perf_pmu_enable(pmu); |
| } |
| |
| static int perf_event_idx_default(struct perf_event *event) |
| { |
| return 0; |
| } |
| |
| /* |
| * Ensures all contexts with the same task_ctx_nr have the same |
| * pmu_cpu_context too. |
| */ |
| static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) |
| { |
| struct pmu *pmu; |
| |
| if (ctxn < 0) |
| return NULL; |
| |
| list_for_each_entry(pmu, &pmus, entry) { |
| if (pmu->task_ctx_nr == ctxn) |
| return pmu->pmu_cpu_context; |
| } |
| |
| return NULL; |
| } |
| |
| static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu) |
| { |
| int cpu; |
| |
| for_each_possible_cpu(cpu) { |
| struct perf_cpu_context *cpuctx; |
| |
| cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); |
| |
| if (cpuctx->unique_pmu == old_pmu) |
| cpuctx->unique_pmu = pmu; |
| } |
| } |
| |
| static void free_pmu_context(struct pmu *pmu) |
| { |
| struct pmu *i; |
| |
| mutex_lock(&pmus_lock); |
| /* |
| * Like a real lame refcount. |
| */ |
| list_for_each_entry(i, &pmus, entry) { |
| if (i->pmu_cpu_context == pmu->pmu_cpu_context) { |
| update_pmu_context(i, pmu); |
| goto out; |
| } |
| } |
| |
| free_percpu(pmu->pmu_cpu_context); |
| out: |
| mutex_unlock(&pmus_lock); |
| } |
| static struct idr pmu_idr; |
| |
| static ssize_t |
| type_show(struct device *dev, struct device_attribute *attr, char *page) |
| { |
| struct pmu *pmu = dev_get_drvdata(dev); |
| |
| return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); |
| } |
| static DEVICE_ATTR_RO(type); |
| |
| static ssize_t |
| perf_event_mux_interval_ms_show(struct device *dev, |
| struct device_attribute *attr, |
| char *page) |
| { |
| struct pmu *pmu = dev_get_drvdata(dev); |
| |
| return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); |
| } |
| |
| static DEFINE_MUTEX(mux_interval_mutex); |
| |
| static ssize_t |
| perf_event_mux_interval_ms_store(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct pmu *pmu = dev_get_drvdata(dev); |
| int timer, cpu, ret; |
| |
| ret = kstrtoint(buf, 0, &timer); |
| if (ret) |
| return ret; |
| |
| if (timer < 1) |
| return -EINVAL; |
| |
| /* same value, noting to do */ |
| if (timer == pmu->hrtimer_interval_ms) |
| return count; |
| |
| mutex_lock(&mux_interval_mutex); |
| pmu->hrtimer_interval_ms = timer; |
| |
| /* update all cpuctx for this PMU */ |
| get_online_cpus(); |
| for_each_online_cpu(cpu) { |
| struct perf_cpu_context *cpuctx; |
| cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); |
| cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); |
| |
| cpu_function_call(cpu, |
| (remote_function_f)perf_mux_hrtimer_restart, cpuctx); |
| } |
| put_online_cpus(); |
| mutex_unlock(&mux_interval_mutex); |
| |
| return count; |
| } |
| static DEVICE_ATTR_RW(perf_event_mux_interval_ms); |
| |
| static struct attribute *pmu_dev_attrs[] = { |
| &dev_attr_type.attr, |
| &dev_attr_perf_event_mux_interval_ms.attr, |
| NULL, |
| }; |
| ATTRIBUTE_GROUPS(pmu_dev); |
| |
| static int pmu_bus_running; |
| static struct bus_type pmu_bus = { |
| .name = "event_source", |
| .dev_groups = pmu_dev_groups, |
| }; |
| |
| static void pmu_dev_release(struct device *dev) |
| { |
| kfree(dev); |
| } |
| |
| static int pmu_dev_alloc(struct pmu *pmu) |
| { |
| int ret = -ENOMEM; |
| |
| pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); |
| if (!pmu->dev) |
| goto out; |
| |
| pmu->dev->groups = pmu->attr_groups; |
| device_initialize(pmu->dev); |
| ret = dev_set_name(pmu->dev, "%s", pmu->name); |
| if (ret) |
| goto free_dev; |
| |
| dev_set_drvdata(pmu->dev, pmu); |
| pmu->dev->bus = &pmu_bus; |
| pmu->dev->release = pmu_dev_release; |
| ret = device_add(pmu->dev); |
| if (ret) |
| goto free_dev; |
| |
| out: |
| return ret; |
| |
| free_dev: |
| put_device(pmu->dev); |
| goto out; |
| } |
| |
| static struct lock_class_key cpuctx_mutex; |
| static struct lock_class_key cpuctx_lock; |
| |
| int perf_pmu_register(struct pmu *pmu, const char *name, int type) |
| { |
| int cpu, ret; |
| |
| mutex_lock(&pmus_lock); |
| ret = -ENOMEM; |
| pmu->pmu_disable_count = alloc_percpu(int); |
| if (!pmu->pmu_disable_count) |
| goto unlock; |
| |
| pmu->type = -1; |
| if (!name) |
| goto skip_type; |
| pmu->name = name; |
| |
| if (type < 0) { |
| type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL); |
| if (type < 0) { |
| ret = type; |
| goto free_pdc; |
| } |
| } |
| pmu->type = type; |
| |
| if (pmu_bus_running) { |
| ret = pmu_dev_alloc(pmu); |
| if (ret) |
| goto free_idr; |
| } |
| |
| skip_type: |
| pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); |
| if (pmu->pmu_cpu_context) |
| goto got_cpu_context; |
| |
| ret = -ENOMEM; |
| pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); |
| if (!pmu->pmu_cpu_context) |
| goto free_dev; |
| |
| for_each_possible_cpu(cpu) { |
| struct perf_cpu_context *cpuctx; |
| |
| cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); |
| __perf_event_init_context(&cpuctx->ctx); |
| lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); |
| lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); |
| cpuctx->ctx.pmu = pmu; |
| |
| __perf_mux_hrtimer_init(cpuctx, cpu); |
| |
| cpuctx->unique_pmu = pmu; |
| } |
| |
| got_cpu_context: |
| if (!pmu->start_txn) { |
| if (pmu->pmu_enable) { |
| /* |
| * If we have pmu_enable/pmu_disable calls, install |
| * transaction stubs that use that to try and batch |
| * hardware accesses. |
| */ |
| pmu->start_txn = perf_pmu_start_txn; |
| pmu->commit_txn = perf_pmu_commit_txn; |
| pmu->cancel_txn = perf_pmu_cancel_txn; |
| } else { |
| pmu->start_txn = perf_pmu_nop_txn; |
| pmu->commit_txn = perf_pmu_nop_int; |
| pmu->cancel_txn = perf_pmu_nop_void; |
| } |
| } |
| |
| if (!pmu->pmu_enable) { |
| pmu->pmu_enable = perf_pmu_nop_void; |
| pmu->pmu_disable = perf_pmu_nop_void; |
| } |
| |
| if (!pmu->event_idx) |
| pmu->event_idx = perf_event_idx_default; |
| |
| list_add_rcu(&pmu->entry, &pmus); |
| atomic_set(&pmu->exclusive_cnt, 0); |
| ret = 0; |
| unlock: |
| mutex_unlock(&pmus_lock); |
| |
| return ret; |
| |
| free_dev: |
| device_del(pmu->dev); |
| put_device(pmu->dev); |
| |
| free_idr: |
| if (pmu->type >= PERF_TYPE_MAX) |
| idr_remove(&pmu_idr, pmu->type); |
| |
| free_pdc: |
| free_percpu(pmu->pmu_disable_count); |
| goto unlock; |
| } |
| EXPORT_SYMBOL_GPL(perf_pmu_register); |
| |
| void perf_pmu_unregister(struct pmu *pmu) |
| { |
| mutex_lock(&pmus_lock); |
| list_del_rcu(&pmu->entry); |
| mutex_unlock(&pmus_lock); |
| |
| /* |
| * We dereference the pmu list under both SRCU and regular RCU, so |
| * synchronize against both of those. |
| */ |
| synchronize_srcu(&pmus_srcu); |
| synchronize_rcu(); |
| |
| free_percpu(pmu->pmu_disable_count); |
| if (pmu->type >= PERF_TYPE_MAX) |
| idr_remove(&pmu_idr, pmu->type); |
| device_del(pmu->dev); |
| put_device(pmu->dev); |
| free_pmu_context(pmu); |
| } |
| EXPORT_SYMBOL_GPL(perf_pmu_unregister); |
| |
| static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) |
| { |
| struct perf_event_context *ctx = NULL; |
| int ret; |
| |
| if (!try_module_get(pmu->module)) |
| return -ENODEV; |
| |
| if (event->group_leader != event) { |
| /* |
| * This ctx->mutex can nest when we're called through |
| * inheritance. See the perf_event_ctx_lock_nested() comment. |
| */ |
| ctx = perf_event_ctx_lock_nested(event->group_leader, |
| SINGLE_DEPTH_NESTING); |
| BUG_ON(!ctx); |
| } |
| |
| event->pmu = pmu; |
| ret = pmu->event_init(event); |
| |
| if (ctx) |
| perf_event_ctx_unlock(event->group_leader, ctx); |
| |
| if (ret) |
| module_put(pmu->module); |
| |
| return ret; |
| } |
| |
| static struct pmu *perf_init_event(struct perf_event *event) |
| { |
| struct pmu *pmu = NULL; |
| int idx; |
| int ret; |
| |
| idx = srcu_read_lock(&pmus_srcu); |
| |
| rcu_read_lock(); |
| pmu = idr_find(&pmu_idr, event->attr.type); |
| rcu_read_unlock(); |
| if (pmu) { |
| ret = perf_try_init_event(pmu, event); |
| if (ret) |
| pmu = ERR_PTR(ret); |
| goto unlock; |
| } |
| |
| list_for_each_entry_rcu(pmu, &pmus, entry) { |
| ret = perf_try_init_event(pmu, event); |
| if (!ret) |
| goto unlock; |
| |
| if (ret != -ENOENT) { |
| pmu = ERR_PTR(ret); |
| goto unlock; |
| } |
| } |
| pmu = ERR_PTR(-ENOENT); |
| unlock: |
| srcu_read_unlock(&pmus_srcu, idx); |
| |
| return pmu; |
| } |
| |
| static void account_event_cpu(struct perf_event *event, int cpu) |
| { |
| if (event->parent) |
| return; |
| |
| if (is_cgroup_event(event)) |
| atomic_inc(&per_cpu(perf_cgroup_events, cpu)); |
| } |
| |
| /* Freq events need the tick to stay alive (see perf_event_task_tick). */ |
| static void account_freq_event_nohz(void) |
| { |
| #ifdef CONFIG_NO_HZ_FULL |
| /* Lock so we don't race with concurrent unaccount */ |
| spin_lock(&nr_freq_lock); |
| if (atomic_inc_return(&nr_freq_events) == 1) |
| tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); |
| spin_unlock(&nr_freq_lock); |
| #endif |
| } |
| |
| static void account_freq_event(void) |
| { |
| if (tick_nohz_full_enabled()) |
| account_freq_event_nohz(); |
| else |
| atomic_inc(&nr_freq_events); |
| } |
| |
| |
| static void account_event(struct perf_event *event) |
| { |
| bool inc = false; |
| |
| if (event->parent) |
| return; |
| |
| if (event->attach_state & PERF_ATTACH_TASK) |
| inc = true; |
| if (event->attr.mmap || event->attr.mmap_data) |
| atomic_inc(&nr_mmap_events); |
| if (event->attr.comm) |
| atomic_inc(&nr_comm_events); |
| if (event->attr.task) |
| atomic_inc(&nr_task_events); |
| if (event->attr.freq) |
| account_freq_event(); |
| if (event->attr.context_switch) { |
| atomic_inc(&nr_switch_events); |
| inc = true; |
| } |
| if (has_branch_stack(event)) |
| inc = true; |
| if (is_cgroup_event(event)) |
| inc = true; |
| |
| if (inc) { |
| if (atomic_inc_not_zero(&perf_sched_count)) |
| goto enabled; |
| |
| mutex_lock(&perf_sched_mutex); |
| if (!atomic_read(&perf_sched_count)) { |
| static_branch_enable(&perf_sched_events); |
| /* |
| * Guarantee that all CPUs observe they key change and |
| * call the perf scheduling hooks before proceeding to |
| * install events that need them. |
| */ |
| synchronize_sched(); |
| } |
| /* |
| * Now that we have waited for the sync_sched(), allow further |
| * increments to by-pass the mutex. |
| */ |
| atomic_inc(&perf_sched_count); |
| mutex_unlock(&perf_sched_mutex); |
| } |
| enabled: |
| |
| account_event_cpu(event, event->cpu); |
| } |
| |
| /* |
| * Allocate and initialize a event structure |
| */ |
| static struct perf_event * |
| perf_event_alloc(struct perf_event_attr *attr, int cpu, |
| struct task_struct *task, |
| struct perf_event *group_leader, |
| struct perf_event *parent_event, |
| perf_overflow_handler_t overflow_handler, |
| void *context, int cgroup_fd) |
| { |
| struct pmu *pmu; |
| struct perf_event *event; |
| struct hw_perf_event *hwc; |
| long err = -EINVAL; |
| |
| if ((unsigned)cpu >= nr_cpu_ids) { |
| if (!task || cpu != -1) |
| return ERR_PTR(-EINVAL); |
| } |
| |
| event = kzalloc(sizeof(*event), GFP_KERNEL); |
| if (!event) |
| return ERR_PTR(-ENOMEM); |
| |
| /* |
| * Single events are their own group leaders, with an |
| * empty sibling list: |
| */ |
| if (!group_leader) |
| group_leader = event; |
| |
| mutex_init(&event->child_mutex); |
| INIT_LIST_HEAD(&event->child_list); |
| |
| INIT_LIST_HEAD(&event->group_entry); |
| INIT_LIST_HEAD(&event->event_entry); |
| INIT_LIST_HEAD(&event->sibling_list); |
| INIT_LIST_HEAD(&event->rb_entry); |
| INIT_LIST_HEAD(&event->active_entry); |
| INIT_HLIST_NODE(&event->hlist_entry); |
| |
| |
| init_waitqueue_head(&event->waitq); |
| init_irq_work(&event->pending, perf_pending_event); |
| |
| mutex_init(&event->mmap_mutex); |
| |
| atomic_long_set(&event->refcount, 1); |
| event->cpu = cpu; |
| event->attr = *attr; |
| event->group_leader = group_leader; |
| event->pmu = NULL; |
| event->oncpu = -1; |
| |
| event->parent = parent_event; |
| |
| event->ns = get_pid_ns(task_active_pid_ns(current)); |
| event->id = atomic64_inc_return(&perf_event_id); |
| |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| |
| if (task) { |
| event->attach_state = PERF_ATTACH_TASK; |
| /* |
| * XXX pmu::event_init needs to know what task to account to |
| * and we cannot use the ctx information because we need the |
| * pmu before we get a ctx. |
| */ |
| event->hw.target = task; |
| } |
| |
| event->clock = &local_clock; |
| if (parent_event) |
| event->clock = parent_event->clock; |
| |
| if (!overflow_handler && parent_event) { |
| overflow_handler = parent_event->overflow_handler; |
| context = parent_event->overflow_handler_context; |
| } |
| |
| event->overflow_handler = overflow_handler; |
| event->overflow_handler_context = context; |
| |
| perf_event__state_init(event); |
| |
| pmu = NULL; |
| |
| hwc = &event->hw; |
| hwc->sample_period = attr->sample_period; |
| if (attr->freq && attr->sample_freq) |
| hwc->sample_period = 1; |
| hwc->last_period = hwc->sample_period; |
| |
| local64_set(&hwc->period_left, hwc->sample_period); |
| |
| /* |
| * we currently do not support PERF_FORMAT_GROUP on inherited events |
| */ |
| if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) |
| goto err_ns; |
| |
| if (!has_branch_stack(event)) |
| event->attr.branch_sample_type = 0; |
| |
| if (cgroup_fd != -1) { |
| err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); |
| if (err) |
| goto err_ns; |
| } |
| |
| pmu = perf_init_event(event); |
| if (!pmu) |
| goto err_ns; |
| else if (IS_ERR(pmu)) { |
| err = PTR_ERR(pmu); |
| goto err_ns; |
| } |
| |
| err = exclusive_event_init(event); |
| if (err) |
| goto err_pmu; |
| |
| if (!event->parent) { |
| if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { |
| err = get_callchain_buffers(); |
| if (err) |
| goto err_per_task; |
| } |
| } |
| |
| /* symmetric to unaccount_event() in _free_event() */ |
| account_event(event); |
| |
| return event; |
| |
| err_per_task: |
| exclusive_event_destroy(event); |
| |
| err_pmu: |
| if (event->destroy) |
| event->destroy(event); |
| module_put(pmu->module); |
| err_ns: |
| if (is_cgroup_event(event)) |
| perf_detach_cgroup(event); |
| if (event->ns) |
| put_pid_ns(event->ns); |
| kfree(event); |
| |
| return ERR_PTR(err); |
| } |
| |
| static int perf_copy_attr(struct perf_event_attr __user *uattr, |
| struct perf_event_attr *attr) |
| { |
| u32 size; |
| int ret; |
| |
| if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) |
| return -EFAULT; |
| |
| /* |
| * zero the full structure, so that a short copy will be nice. |
| */ |
| memset(attr, 0, sizeof(*attr)); |
| |
| ret = get_user(size, &uattr->size); |
| if (ret) |
| return ret; |
| |
| if (size > PAGE_SIZE) /* silly large */ |
| goto err_size; |
| |
| if (!size) /* abi compat */ |
| size = PERF_ATTR_SIZE_VER0; |
| |
| if (size < PERF_ATTR_SIZE_VER0) |
| goto err_size; |
| |
| /* |
| * If we're handed a bigger struct than we know of, |
| * ensure all the unknown bits are 0 - i.e. new |
| * user-space does not rely on any kernel feature |
| * extensions we dont know about yet. |
| */ |
| if (size > sizeof(*attr)) { |
| unsigned char __user *addr; |
| unsigned char __user *end; |
| unsigned char val; |
| |
| addr = (void __user *)uattr + sizeof(*attr); |
| end = (void __user *)uattr + size; |
| |
| for (; addr < end; addr++) { |
| ret = get_user(val, addr); |
| if (ret) |
| return ret; |
| if (val) |
| goto err_size; |
| } |
| size = sizeof(*attr); |
| } |
| |
| ret = copy_from_user(attr, uattr, size); |
| if (ret) |
| return -EFAULT; |
| |
| if (attr->__reserved_1) |
| return -EINVAL; |
| |
| if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) |
| return -EINVAL; |
| |
| if (attr->read_format & ~(PERF_FORMAT_MAX-1)) |
| return -EINVAL; |
| |
| if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { |
| u64 mask = attr->branch_sample_type; |
| |
| /* only using defined bits */ |
| if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) |
| return -EINVAL; |
| |
| /* at least one branch bit must be set */ |
| if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) |
| return -EINVAL; |
| |
| /* propagate priv level, when not set for branch */ |
| if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { |
| |
| /* exclude_kernel checked on syscall entry */ |
| if (!attr->exclude_kernel) |
| mask |= PERF_SAMPLE_BRANCH_KERNEL; |
| |
| if (!attr->exclude_user) |
| mask |= PERF_SAMPLE_BRANCH_USER; |
| |
| if (!attr->exclude_hv) |
| mask |= PERF_SAMPLE_BRANCH_HV; |
| /* |
| * adjust user setting (for HW filter setup) |
| */ |
| attr->branch_sample_type = mask; |
| } |
| /* privileged levels capture (kernel, hv): check permissions */ |
| if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) |
| && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) |
| return -EACCES; |
| } |
| |
| if (attr->sample_type & PERF_SAMPLE_REGS_USER) { |
| ret = perf_reg_validate(attr->sample_regs_user); |
| if (ret) |
| return ret; |
| } |
| |
| if (attr->sample_type & PERF_SAMPLE_STACK_USER) { |
| if (!arch_perf_have_user_stack_dump()) |
| return -ENOSYS; |
| |
| /* |
| * We have __u32 type for the size, but so far |
| * we can only use __u16 as maximum due to the |
| * __u16 sample size limit. |
| */ |
| if (attr->sample_stack_user >= USHRT_MAX) |
| ret = -EINVAL; |
| else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) |
| ret = -EINVAL; |
| } |
| |
| if (attr->sample_type & PERF_SAMPLE_REGS_INTR) |
| ret = perf_reg_validate(attr->sample_regs_intr); |
| out: |
| return ret; |
| |
| err_size: |
| put_user(sizeof(*attr), &uattr->size); |
| ret = -E2BIG; |
| goto out; |
| } |
| |
| static int |
| perf_event_set_output(struct perf_event *event, struct perf_event *output_event) |
| { |
| struct ring_buffer *rb = NULL; |
| int ret = -EINVAL; |
| |
| if (!output_event) |
| goto set; |
| |
| /* don't allow circular references */ |
| if (event == output_event) |
| goto out; |
| |
| /* |
| * Don't allow cross-cpu buffers |
| */ |
| if (output_event->cpu != event->cpu) |
| goto out; |
| |
| /* |
| * If its not a per-cpu rb, it must be the same task. |
| */ |
| if (output_event->cpu == -1 && output_event->ctx != event->ctx) |
| goto out; |
| |
| /* |
| * Mixing clocks in the same buffer is trouble you don't need. |
| */ |
| if (output_event->clock != event->clock) |
| goto out; |
| |
| /* |
| * If both events generate aux data, they must be on the same PMU |
| */ |
| if (has_aux(event) && has_aux(output_event) && |
| event->pmu != output_event->pmu) |
| goto out; |
| |
| set: |
| mutex_lock(&event->mmap_mutex); |
| /* Can't redirect output if we've got an active mmap() */ |
| if (atomic_read(&event->mmap_count)) |
| goto unlock; |
| |
| if (output_event) { |
| /* get the rb we want to redirect to */ |
| rb = ring_buffer_get(output_event); |
| if (!rb) |
| goto unlock; |
| } |
| |
| ring_buffer_attach(event, rb); |
| |
| ret = 0; |
| unlock: |
| mutex_unlock(&event->mmap_mutex); |
| |
| out: |
| return ret; |
| } |
| |
| static void mutex_lock_double(struct mutex *a, struct mutex *b) |
| { |
| if (b < a) |
| swap(a, b); |
| |
| mutex_lock(a); |
| mutex_lock_nested(b, SINGLE_DEPTH_NESTING); |
| } |
| |
| static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) |
| { |
| bool nmi_safe = false; |
| |
| switch (clk_id) { |
| case CLOCK_MONOTONIC: |
| event->clock = &ktime_get_mono_fast_ns; |
| nmi_safe = true; |
| break; |
| |
| case CLOCK_MONOTONIC_RAW: |
| event->clock = &ktime_get_raw_fast_ns; |
| nmi_safe = true; |
| break; |
| |
| case CLOCK_REALTIME: |
| event->clock = &ktime_get_real_ns; |
| break; |
| |
| case CLOCK_BOOTTIME: |
| event->clock = &ktime_get_boot_ns; |
| break; |
| |
| case CLOCK_TAI: |
| event->clock = &ktime_get_tai_ns; |
| break; |
| |
| default: |
| return -EINVAL; |
| } |
| |
| if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| /** |
| * sys_perf_event_open - open a performance event, associate it to a task/cpu |
| * |
| * @attr_uptr: event_id type attributes for monitoring/sampling |
| * @pid: target pid |
| * @cpu: target cpu |
| * @group_fd: group leader event fd |
| */ |
| SYSCALL_DEFINE5(perf_event_open, |
| struct perf_event_attr __user *, attr_uptr, |
| pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) |
| { |
| struct perf_event *group_leader = NULL, *output_event = NULL; |
| struct perf_event *event, *sibling; |
| struct perf_event_attr attr; |
| struct perf_event_context *ctx, *uninitialized_var(gctx); |
| struct file *event_file = NULL; |
| struct fd group = {NULL, 0}; |
| struct task_struct *task = NULL; |
| struct pmu *pmu; |
| int event_fd; |
| int move_group = 0; |
| int err; |
| int f_flags = O_RDWR; |
| int cgroup_fd = -1; |
| |
| /* for future expandability... */ |
| if (flags & ~PERF_FLAG_ALL) |
| return -EINVAL; |
| |
| err = perf_copy_attr(attr_uptr, &attr); |
| if (err) |
| return err; |
| |
| if (!attr.exclude_kernel) { |
| if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) |
| return -EACCES; |
| } |
| |
| if (attr.freq) { |
| if (attr.sample_freq > sysctl_perf_event_sample_rate) |
| return -EINVAL; |
| } else { |
| if (attr.sample_period & (1ULL << 63)) |
| return -EINVAL; |
| } |
| |
| /* |
| * In cgroup mode, the pid argument is used to pass the fd |
| * opened to the cgroup directory in cgroupfs. The cpu argument |
| * designates the cpu on which to monitor threads from that |
| * cgroup. |
| */ |
| if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) |
| return -EINVAL; |
| |
| if (flags & PERF_FLAG_FD_CLOEXEC) |
| f_flags |= O_CLOEXEC; |
| |
| event_fd = get_unused_fd_flags(f_flags); |
| if (event_fd < 0) |
| return event_fd; |
| |
| if (group_fd != -1) { |
| err = perf_fget_light(group_fd, &group); |
| if (err) |
| goto err_fd; |
| group_leader = group.file->private_data; |
| if (flags & PERF_FLAG_FD_OUTPUT) |
| output_event = group_leader; |
| if (flags & PERF_FLAG_FD_NO_GROUP) |
| group_leader = NULL; |
| } |
| |
| if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { |
| task = find_lively_task_by_vpid(pid); |
| if (IS_ERR(task)) { |
| err = PTR_ERR(task); |
| goto err_group_fd; |
| } |
| } |
| |
| if (task && group_leader && |
| group_leader->attr.inherit != attr.inherit) { |
| err = -EINVAL; |
| goto err_task; |
| } |
| |
| get_online_cpus(); |
| |
| if (flags & PERF_FLAG_PID_CGROUP) |
| cgroup_fd = pid; |
| |
| event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, |
| NULL, NULL, cgroup_fd); |
| if (IS_ERR(event)) { |
| err = PTR_ERR(event); |
| goto err_cpus; |
| } |
| |
| if (is_sampling_event(event)) { |
| if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { |
| err = -ENOTSUPP; |
| goto err_alloc; |
| } |
| } |
| |
| /* |
| * Special case software events and allow them to be part of |
| * any hardware group. |
| */ |
| pmu = event->pmu; |
| |
| if (attr.use_clockid) { |
| err = perf_event_set_clock(event, attr.clockid); |
| if (err) |
| goto err_alloc; |
| } |
| |
| if (group_leader && |
| (is_software_event(event) != is_software_event(group_leader))) { |
| if (is_software_event(event)) { |
| /* |
| * If event and group_leader are not both a software |
| * event, and event is, then group leader is not. |
| * |
| * Allow the addition of software events to !software |
| * groups, this is safe because software events never |
| * fail to schedule. |
| */ |
| pmu = group_leader->pmu; |
| } else if (is_software_event(group_leader) && |
| (group_leader->group_flags & PERF_GROUP_SOFTWARE)) { |
| /* |
| * In case the group is a pure software group, and we |
| * try to add a hardware event, move the whole group to |
| * the hardware context. |
| */ |
| move_group = 1; |
| } |
| } |
| |
| /* |
| * Get the target context (task or percpu): |
| */ |
| ctx = find_get_context(pmu, task, event); |
| if (IS_ERR(ctx)) { |
| err = PTR_ERR(ctx); |
| goto err_alloc; |
| } |
| |
| if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) { |
| err = -EBUSY; |
| goto err_context; |
| } |
| |
| if (task) { |
| put_task_struct(task); |
| task = NULL; |
| } |
| |
| /* |
| * Look up the group leader (we will attach this event to it): |
| */ |
| if (group_leader) { |
| err = -EINVAL; |
| |
| /* |
| * Do not allow a recursive hierarchy (this new sibling |
| * becoming part of another group-sibling): |
| */ |
| if (group_leader->group_leader != group_leader) |
| goto err_context; |
| |
| /* All events in a group should have the same clock */ |
| if (group_leader->clock != event->clock) |
| goto err_context; |
| |
| /* |
| * Do not allow to attach to a group in a different |
| * task or CPU context: |
| */ |
| if (move_group) { |
| /* |
| * Make sure we're both on the same task, or both |
| * per-cpu events. |
| */ |
| if (group_leader->ctx->task != ctx->task) |
| goto err_context; |
| |
| /* |
| * Make sure we're both events for the same CPU; |
| * grouping events for different CPUs is broken; since |
| * you can never concurrently schedule them anyhow. |
| */ |
| if (group_leader->cpu != event->cpu) |
| goto err_context; |
| } else { |
| if (group_leader->ctx != ctx) |
| goto err_context; |
| } |
| |
| /* |
| * Only a group leader can be exclusive or pinned |
| */ |
| if (attr.exclusive || attr.pinned) |
| goto err_context; |
| } |
| |
| if (output_event) { |
| err = perf_event_set_output(event, output_event); |
| if (err) |
| goto err_context; |
| } |
| |
| event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, |
| f_flags); |
| if (IS_ERR(event_file)) { |
| err = PTR_ERR(event_file); |
| goto err_context; |
| } |
| |
| if (move_group) { |
| gctx = group_leader->ctx; |
| mutex_lock_double(&gctx->mutex, &ctx->mutex); |
| if (gctx->task == TASK_TOMBSTONE) { |
| err = -ESRCH; |
| goto err_locked; |
| } |
| } else { |
| mutex_lock(&ctx->mutex); |
| } |
| |
| if (ctx->task == TASK_TOMBSTONE) { |
| err = -ESRCH; |
| goto err_locked; |
| } |
| |
| if (!perf_event_validate_size(event)) { |
| err = -E2BIG; |
| goto err_locked; |
| } |
| |
| /* |
| * Must be under the same ctx::mutex as perf_install_in_context(), |
| * because we need to serialize with concurrent event creation. |
| */ |
| if (!exclusive_event_installable(event, ctx)) { |
| /* exclusive and group stuff are assumed mutually exclusive */ |
| WARN_ON_ONCE(move_group); |
| |
| err = -EBUSY; |
| goto err_locked; |
| } |
| |
| WARN_ON_ONCE(ctx->parent_ctx); |
| |
| if (move_group) { |
| /* |
| * See perf_event_ctx_lock() for comments on the details |
| * of swizzling perf_event::ctx. |
| */ |
| perf_remove_from_context(group_leader, 0); |
| |
| list_for_each_entry(sibling, &group_leader->sibling_list, |
| group_entry) { |
| perf_remove_from_context(sibling, 0); |
| put_ctx(gctx); |
| } |
| |
| /* |
| * Wait for everybody to stop referencing the events through |
| * the old lists, before installing it on new lists. |
| */ |
| synchronize_rcu(); |
| |
| /* |
| * Install the group siblings before the group leader. |
| * |
| * Because a group leader will try and install the entire group |
| * (through the sibling list, which is still in-tact), we can |
| * end up with siblings installed in the wrong context. |
| * |
| * By installing siblings first we NO-OP because they're not |
| * reachable through the group lists. |
| */ |
| list_for_each_entry(sibling, &group_leader->sibling_list, |
| group_entry) { |
| perf_event__state_init(sibling); |
| perf_install_in_context(ctx, sibling, sibling->cpu); |
| get_ctx(ctx); |
| } |
| |
| /* |
| * Removing from the context ends up with disabled |
| * event. What we want here is event in the initial |
| * startup state, ready to be add into new context. |
| */ |
| perf_event__state_init(group_leader); |
| perf_install_in_context(ctx, group_leader, group_leader->cpu); |
| get_ctx(ctx); |
| |
| /* |
| * Now that all events are installed in @ctx, nothing |
| * references @gctx anymore, so drop the last reference we have |
| * on it. |
| */ |
| put_ctx(gctx); |
| } |
| |
| /* |
| * Precalculate sample_data sizes; do while holding ctx::mutex such |
| * that we're serialized against further additions and before |
| * perf_install_in_context() which is the point the event is active and |
| * can use these values. |
| */ |
| perf_event__header_size(event); |
| perf_event__id_header_size(event); |
| |
| event->owner = current; |
| |
| perf_install_in_context(ctx, event, event->cpu); |
| perf_unpin_context(ctx); |
| |
| if (move_group) |
| mutex_unlock(&gctx->mutex); |
| mutex_unlock(&ctx->mutex); |
| |
| put_online_cpus(); |
| |
| mutex_lock(¤t->perf_event_mutex); |
| list_add_tail(&event->owner_entry, ¤t->perf_event_list); |
| mutex_unlock(¤t->perf_event_mutex); |
| |
| /* |
| * Drop the reference on the group_event after placing the |
| * new event on the sibling_list. This ensures destruction |
| * of the group leader will find the pointer to itself in |
| * perf_group_detach(). |
| */ |
| fdput(group); |
| fd_install(event_fd, event_file); |
| return event_fd; |
| |
| err_locked: |
| if (move_group) |
| mutex_unlock(&gctx->mutex); |
| mutex_unlock(&ctx->mutex); |
| /* err_file: */ |
| fput(event_file); |
| err_context: |
| perf_unpin_context(ctx); |
| put_ctx(ctx); |
| err_alloc: |
| /* |
| * If event_file is set, the fput() above will have called ->release() |
| * and that will take care of freeing the event. |
| */ |
| if (!event_file) |
| free_event(event); |
| err_cpus: |
| put_online_cpus(); |
| err_task: |
| if (task) |
| put_task_struct(task); |
| err_group_fd: |
| fdput(group); |
| err_fd: |
| put_unused_fd(event_fd); |
| return err; |
| } |
| |
| /** |
| * perf_event_create_kernel_counter |
| * |
| * @attr: attributes of the counter to create |
| * @cpu: cpu in which the counter is bound |
| * @task: task to profile (NULL for percpu) |
| */ |
| struct perf_event * |
| perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, |
| struct task_struct *task, |
| perf_overflow_handler_t overflow_handler, |
| void *context) |
| { |
| struct perf_event_context *ctx; |
| struct perf_event *event; |
| int err; |
| |
| /* |
| * Get the target context (task or percpu): |
| */ |
| |
| event = perf_event_alloc(attr, cpu, task, NULL, NULL, |
| overflow_handler, context, -1); |
| if (IS_ERR(event)) { |
| err = PTR_ERR(event); |
| goto err; |
| } |
| |
| /* Mark owner so we could distinguish it from user events. */ |
| event->owner = TASK_TOMBSTONE; |
| |
| ctx = find_get_context(event->pmu, task, event); |
| if (IS_ERR(ctx)) { |
| err = PTR_ERR(ctx); |
| goto err_free; |
| } |
| |
| WARN_ON_ONCE(ctx->parent_ctx); |
| mutex_lock(&ctx->mutex); |
| if (ctx->task == TASK_TOMBSTONE) { |
| err = -ESRCH; |
| goto err_unlock; |
| } |
| |
| if (!exclusive_event_installable(event, ctx)) { |
| err = -EBUSY; |
| goto err_unlock; |
| } |
| |
| perf_install_in_context(ctx, event, cpu); |
| perf_unpin_context(ctx); |
| mutex_unlock(&ctx->mutex); |
| |
| return event; |
| |
| err_unlock: |
| mutex_unlock(&ctx->mutex); |
| perf_unpin_context(ctx); |
| put_ctx(ctx); |
| err_free: |
| free_event(event); |
| err: |
| return ERR_PTR(err); |
| } |
| EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); |
| |
| void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) |
| { |
| struct perf_event_context *src_ctx; |
| struct perf_event_context *dst_ctx; |
| struct perf_event *event, *tmp; |
| LIST_HEAD(events); |
| |
| src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; |
| dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; |
| |
| /* |
| * See perf_event_ctx_lock() for comments on the details |
| * of swizzling perf_event::ctx. |
| */ |
| mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); |
| list_for_each_entry_safe(event, tmp, &src_ctx->event_list, |
| event_entry) { |
| perf_remove_from_context(event, 0); |
| unaccount_event_cpu(event, src_cpu); |
| put_ctx(src_ctx); |
| list_add(&event->migrate_entry, &events); |
| } |
| |
| /* |
| * Wait for the events to quiesce before re-instating them. |
| */ |
| synchronize_rcu(); |
| |
| /* |
| * Re-instate events in 2 passes. |
| * |
| * Skip over group leaders and only install siblings on this first |
| * pass, siblings will not get enabled without a leader, however a |
| * leader will enable its siblings, even if those are still on the old |
| * context. |
| */ |
| list_for_each_entry_safe(event, tmp, &events, migrate_entry) { |
| if (event->group_leader == event) |
| continue; |
| |
| list_del(&event->migrate_entry); |
| if (event->state >= PERF_EVENT_STATE_OFF) |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| account_event_cpu(event, dst_cpu); |
| perf_install_in_context(dst_ctx, event, dst_cpu); |
| get_ctx(dst_ctx); |
| } |
| |
| /* |
| * Once all the siblings are setup properly, install the group leaders |
| * to make it go. |
| */ |
| list_for_each_entry_safe(event, tmp, &events, migrate_entry) { |
| list_del(&event->migrate_entry); |
| if (event->state >= PERF_EVENT_STATE_OFF) |
| event->state = PERF_EVENT_STATE_INACTIVE; |
| account_event_cpu(event, dst_cpu); |
| perf_install_in_context(dst_ctx, event, dst_cpu); |
| get_ctx(dst_ctx); |
| } |
| mutex_unlock(&dst_ctx->mutex); |
| mutex_unlock(&src_ctx->mutex); |
| } |
| EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); |
| |
| static void sync_child_event(struct perf_event *child_event, |
| struct task_struct *child) |
| { |
| struct perf_event *parent_event = child_event->parent; |
| u64 child_val; |
| |
| if (child_event->attr.inherit_stat) |
| perf_event_read_event(child_event, child); |
| |
| child_val = perf_event_count(child_event); |
| |
| /* |
| * Add back the child's count to the parent's count: |
| */ |
| atomic64_add(child_val, &parent_event->child_count); |
| atomic64_add(child_event->total_time_enabled, |
| &parent_event->child_total_time_enabled); |
| atomic64_add(child_event->total_time_running, |
| &parent_event->child_total_time_running); |
| } |
| |
| static void |
| perf_event_exit_event(struct perf_event *child_event, |
| struct perf_event_context *child_ctx, |
| struct task_struct *child) |
| { |
| struct perf_event *parent_event = child_event->parent; |
| |
| /* |
| * Do not destroy the 'original' grouping; because of the context |
| * switch optimization the original events could've ended up in a |
| * random child task. |
| * |
| * If we were to destroy the original group, all group related |
| * operations would cease to function properly after this random |
| * child dies. |
| * |
| * Do destroy all inherited groups, we don't care about those |
| * and being thorough is better. |
| */ |
| raw_spin_lock_irq(&child_ctx->lock); |
| WARN_ON_ONCE(child_ctx->is_active); |
| |
| if (parent_event) |
| perf_group_detach(child_event); |
| list_del_event(child_event, child_ctx); |
| child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */ |
| raw_spin_unlock_irq(&child_ctx->lock); |
| |
| /* |
| * Parent events are governed by their filedesc, retain them. |
| */ |
| if (!parent_event) { |
| perf_event_wakeup(child_event); |
| return; |
| } |
| /* |
| * Child events can be cleaned up. |
| */ |
| |
| sync_child_event(child_event, child); |
| |
| /* |
| * Remove this event from the parent's list |
| */ |
| WARN_ON_ONCE(parent_event->ctx->parent_ctx); |
| mutex_lock(&parent_event->child_mutex); |
| list_del_init(&child_event->child_list); |
| mutex_unlock(&parent_event->child_mutex); |
| |
| /* |
| * Kick perf_poll() for is_event_hup(). |
| */ |
| perf_event_wakeup(parent_event); |
| free_event(child_event); |
| put_event(parent_event); |
| } |
| |
| static void perf_event_exit_task_context(struct task_struct *child, int ctxn) |
| { |
| struct perf_event_context *child_ctx, *clone_ctx = NULL; |
| struct perf_event *child_event, *next; |
| |
| WARN_ON_ONCE(child != current); |
| |
| child_ctx = perf_pin_task_context(child, ctxn); |
| if (!child_ctx) |
| return; |
| |
| /* |
| * In order to reduce the amount of tricky in ctx tear-down, we hold |
| * ctx::mutex over the entire thing. This serializes against almost |
| * everything that wants to access the ctx. |
| * |
| * The exception is sys_perf_event_open() / |
| * perf_event_create_kernel_count() which does find_get_context() |
| * without ctx::mutex (it cannot because of the move_group double mutex |
| * lock thing). See the comments in perf_install_in_context(). |
| */ |
| mutex_lock(&child_ctx->mutex); |
| |
| /* |
| * In a single ctx::lock section, de-schedule the events and detach the |
| * context from the task such that we cannot ever get it scheduled back |
| * in. |
| */ |
| raw_spin_lock_irq(&child_ctx->lock); |
| task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx); |
| |
| /* |
| * Now that the context is inactive, destroy the task <-> ctx relation |
| * and mark the context dead. |
| */ |
| RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); |
| put_ctx(child_ctx); /* cannot be last */ |
| WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); |
| put_task_struct(current); /* cannot be last */ |
| |
| clone_ctx = unclone_ctx(child_ctx); |
| raw_spin_unlock_irq(&child_ctx->lock); |
| |
| if (clone_ctx) |
| put_ctx(clone_ctx); |
| |
| /* |
| * Report the task dead after unscheduling the events so that we |
| * won't get any samples after PERF_RECORD_EXIT. We can however still |
| * get a few PERF_RECORD_READ events. |
| */ |
| perf_event_task(child, child_ctx, 0); |
| |
| list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) |
| perf_event_exit_event(child_event, child_ctx, child); |
| |
| mutex_unlock(&child_ctx->mutex); |
| |
| put_ctx(child_ctx); |
| } |
| |
| /* |
| * When a child task exits, feed back event values to parent events. |
| */ |
| void perf_event_exit_task(struct task_struct *child) |
| { |
| struct perf_event *event, *tmp; |
| int ctxn; |
| |
| mutex_lock(&child->perf_event_mutex); |
| list_for_each_entry_safe(event, tmp, &child->perf_event_list, |
| owner_entry) { |
| list_del_init(&event->owner_entry); |
| |
| /* |
| * Ensure the list deletion is visible before we clear |
| * the owner, closes a race against perf_release() where |
| * we need to serialize on the owner->perf_event_mutex. |
| */ |
| smp_store_release(&event->owner, NULL); |
| } |
| mutex_unlock(&child->perf_event_mutex); |
| |
| for_each_task_context_nr(ctxn) |
| perf_event_exit_task_context(child, ctxn); |
| |
| /* |
| * The perf_event_exit_task_context calls perf_event_task |
| * with child's task_ctx, which generates EXIT events for |
| * child contexts and sets child->perf_event_ctxp[] to NULL. |
| * At this point we need to send EXIT events to cpu contexts. |
| */ |
| perf_event_task(child, NULL, 0); |
| } |
| |
| static void perf_free_event(struct perf_event *event, |
| struct perf_event_context *ctx) |
| { |
| struct perf_event *parent = event->parent; |
| |
| if (WARN_ON_ONCE(!parent)) |
| return; |
| |
| mutex_lock(&parent->child_mutex); |
| list_del_init(&event->child_list); |
| mutex_unlock(&parent->child_mutex); |
| |
| put_event(parent); |
| |
| raw_spin_lock_irq(&ctx->lock); |
| perf_group_detach(event); |
| list_del_event(event, ctx); |
| raw_spin_unlock_irq(&ctx->lock); |
| free_event(event); |
| } |
| |
| /* |
| * Free an unexposed, unused context as created by inheritance by |
| * perf_event_init_task below, used by fork() in case of fail. |
| * |
| * Not all locks are strictly required, but take them anyway to be nice and |
| * help out with the lockdep assertions. |
| */ |
| void perf_event_free_task(struct task_struct *task) |
| { |
| struct perf_event_context *ctx; |
| struct perf_event *event, *tmp; |
| int ctxn; |
| |
| for_each_task_context_nr(ctxn) { |
| ctx = task->perf_event_ctxp[ctxn]; |
| if (!ctx) |
| continue; |
| |
| mutex_lock(&ctx->mutex); |
| again: |
| list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, |
| group_entry) |
| perf_free_event(event, ctx); |
| |
| list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, |
| group_entry) |
| perf_free_event(event, ctx); |
| |
| if (!list_empty(&ctx->pinned_groups) || |
| !list_empty(&ctx->flexible_groups)) |
| goto again; |
| |
| mutex_unlock(&ctx->mutex); |
| |
| put_ctx(ctx); |
| } |
| } |
| |
| void perf_event_delayed_put(struct task_struct *task) |
| { |
| int ctxn; |
| |
| for_each_task_context_nr(ctxn) |
| WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); |
| } |
| |
| struct file *perf_event_get(unsigned int fd) |
| { |
| struct file *file; |
| |
| file = fget_raw(fd); |
| if (!file) |
| return ERR_PTR(-EBADF); |
| |
| if (file->f_op != &perf_fops) { |
| fput(file); |
| return ERR_PTR(-EBADF); |
| } |
| |
| return file; |
| } |
| |
| const struct perf_event_attr *perf_event_attrs(struct perf_event *event) |
| { |
| if (!event) |
| return ERR_PTR(-EINVAL); |
| |
| return &event->attr; |
| } |
| |
| /* |
| * inherit a event from parent task to child task: |
| */ |
| static struct perf_event * |
| inherit_event(struct perf_event *parent_event, |
| struct task_struct *parent, |
| struct perf_event_context *parent_ctx, |
| struct task_struct *child, |
| struct perf_event *group_leader, |
| struct perf_event_context *child_ctx) |
| { |
| enum perf_event_active_state parent_state = parent_event->state; |
| struct perf_event *child_event; |
| unsigned long flags; |
| |
| /* |
| * Instead of creating recursive hierarchies of events, |
| * we link inherited events back to the original parent, |
| * which has a filp for sure, which we use as the reference |
| * count: |
| */ |
| if (parent_event->parent) |
| parent_event = parent_event->parent; |
| |
| child_event = perf_event_alloc(&parent_event->attr, |
| parent_event->cpu, |
| child, |
| group_leader, parent_event, |
| NULL, NULL, -1); |
| if (IS_ERR(child_event)) |
| return child_event; |
| |
| /* |
| * is_orphaned_event() and list_add_tail(&parent_event->child_list) |
| * must be under the same lock in order to serialize against |
| * perf_event_release_kernel(), such that either we must observe |
| * is_orphaned_event() or they will observe us on the child_list. |
| */ |
| mutex_lock(&parent_event->child_mutex); |
| if (is_orphaned_event(parent_event) || |
| !atomic_long_inc_not_zero(&parent_event->refcount)) { |
| mutex_unlock(&parent_event->child_mutex); |
| free_event(child_event); |
| return NULL; |
| } |
| |
| get_ctx(child_ctx); |
| |
| /* |
| * Make the child state follow the state of the parent event, |
| * not its attr.disabled bit. We hold the parent's mutex, |
| * so we won't race with perf_event_{en, dis}able_family. |
| */ |
| if (parent_state >= PERF_EVENT_STATE_INACTIVE) |
| child_event->state = PERF_EVENT_STATE_INACTIVE; |
| else |
| child_event->state = PERF_EVENT_STATE_OFF; |
| |
| if (parent_event->attr.freq) { |
| u64 sample_period = parent_event->hw.sample_period; |
| struct hw_perf_event *hwc = &child_event->hw; |
| |
| hwc->sample_period = sample_period; |
| hwc->last_period = sample_period; |
| |
| local64_set(&hwc->period_left, sample_period); |
| } |
| |
| child_event->ctx = child_ctx; |
| child_event->overflow_handler = parent_event->overflow_handler; |
| child_event->overflow_handler_context |
| = parent_event->overflow_handler_context; |
| |
| /* |
| * Precalculate sample_data sizes |
| */ |
| perf_event__header_size(child_event); |
| perf_event__id_header_size(child_event); |
| |
| /* |
| * Link it up in the child's context: |
| */ |
| raw_spin_lock_irqsave(&child_ctx->lock, flags); |
| add_event_to_ctx(child_event, child_ctx); |
| raw_spin_unlock_irqrestore(&child_ctx->lock, flags); |
| |
| /* |
| * Link this into the parent event's child list |
| */ |
| list_add_tail(&child_event->child_list, &parent_event->child_list); |
| mutex_unlock(&parent_event->child_mutex); |
| |
| return child_event; |
| } |
| |
| static int inherit_group(struct perf_event *parent_event, |
| struct task_struct *parent, |
| struct perf_event_context *parent_ctx, |
| struct task_struct *child, |
| struct perf_event_context *child_ctx) |
| { |
| struct perf_event *leader; |
| struct perf_event *sub; |
| struct perf_event *child_ctr; |
| |
| leader = inherit_event(parent_event, parent, parent_ctx, |
| child, NULL, child_ctx); |
| if (IS_ERR(leader)) |
| return PTR_ERR(leader); |
| list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { |
| child_ctr = inherit_event(sub, parent, parent_ctx, |
| child, leader, child_ctx); |
| if (IS_ERR(child_ctr)) |
| return PTR_ERR(child_ctr); |
| } |
| return 0; |
| } |
| |
| static int |
| inherit_task_group(struct perf_event *event, struct task_struct *parent, |
| struct perf_event_context *parent_ctx, |
| struct task_struct *child, int ctxn, |
| int *inherited_all) |
| { |
| int ret; |
| struct perf_event_context *child_ctx; |
| |
| if (!event->attr.inherit) { |
| *inherited_all = 0; |
| return 0; |
| } |
| |
| child_ctx = child->perf_event_ctxp[ctxn]; |
| if (!child_ctx) { |
| /* |
| * This is executed from the parent task context, so |
| * inherit events that have been marked for cloning. |
| * First allocate and initialize a context for the |
| * child. |
| */ |
| |
| child_ctx = alloc_perf_context(parent_ctx->pmu, child); |
| if (!child_ctx) |
| return -ENOMEM; |
| |
| child->perf_event_ctxp[ctxn] = child_ctx; |
| } |
| |
| ret = inherit_group(event, parent, parent_ctx, |
| child, child_ctx); |
| |
| if (ret) |
| *inherited_all = 0; |
| |
| return ret; |
| } |
| |
| /* |
| * Initialize the perf_event context in task_struct |
| */ |
| static int perf_event_init_context(struct task_struct *child, int ctxn) |
| { |
| struct perf_event_context *child_ctx, *parent_ctx; |
| struct perf_event_context *cloned_ctx; |
| struct perf_event *event; |
| struct task_struct *parent = current; |
| int inherited_all = 1; |
| unsigned long flags; |
| int ret = 0; |
| |
| if (likely(!parent->perf_event_ctxp[ctxn])) |
| return 0; |
| |
| /* |
| * If the parent's context is a clone, pin it so it won't get |
| * swapped under us. |
| */ |
| parent_ctx = perf_pin_task_context(parent, ctxn); |
| if (!parent_ctx) |
| return 0; |
| |
| /* |
| * No need to check if parent_ctx != NULL here; since we saw |
| * it non-NULL earlier, the only reason for it to become NULL |
| * is if we exit, and since we're currently in the middle of |
| * a fork we can't be exiting at the same time. |
| */ |
| |
| /* |
| * Lock the parent list. No need to lock the child - not PID |
| * hashed yet and not running, so nobody can access it. |
| */ |
| mutex_lock(&parent_ctx->mutex); |
| |
| /* |
| * We dont have to disable NMIs - we are only looking at |
| * the list, not manipulating it: |
| */ |
| list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { |
| ret = inherit_task_group(event, parent, parent_ctx, |
| child, ctxn, &inherited_all); |
| if (ret) |
| break; |
| } |
| |
| /* |
| * We can't hold ctx->lock when iterating the ->flexible_group list due |
| * to allocations, but we need to prevent rotation because |
| * rotate_ctx() will change the list from interrupt context. |
| */ |
| raw_spin_lock_irqsave(&parent_ctx->lock, flags); |
| parent_ctx->rotate_disable = 1; |
| raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); |
| |
| list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { |
| ret = inherit_task_group(event, parent, parent_ctx, |
| child, ctxn, &inherited_all); |
| if (ret) |
| break; |
| } |
| |
| raw_spin_lock_irqsave(&parent_ctx->lock, flags); |
| parent_ctx->rotate_disable = 0; |
| |
| child_ctx = child->perf_event_ctxp[ctxn]; |
| |
| if (child_ctx && inherited_all) { |
| /* |
| * Mark the child context as a clone of the parent |
| * context, or of whatever the parent is a clone of. |
| * |
| * Note that if the parent is a clone, the holding of |
| * parent_ctx->lock avoids it from being uncloned. |
| */ |
| cloned_ctx = parent_ctx->parent_ctx; |
| if (cloned_ctx) { |
| child_ctx->parent_ctx = cloned_ctx; |
| child_ctx->parent_gen = parent_ctx->parent_gen; |
| } else { |
| child_ctx->parent_ctx = parent_ctx; |
| child_ctx->parent_gen = parent_ctx->generation; |
| } |
| get_ctx(child_ctx->parent_ctx); |
| } |
| |
| raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); |
| mutex_unlock(&parent_ctx->mutex); |
| |
| perf_unpin_context(parent_ctx); |
| put_ctx(parent_ctx); |
| |
| return ret; |
| } |
| |
| /* |
| * Initialize the perf_event context in task_struct |
| */ |
| int perf_event_init_task(struct task_struct *child) |
| { |
| int ctxn, ret; |
| |
| memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); |
| mutex_init(&child->perf_event_mutex); |
| INIT_LIST_HEAD(&child->perf_event_list); |
| |
| for_each_task_context_nr(ctxn) { |
| ret = perf_event_init_context(child, ctxn); |
| if (ret) { |
| perf_event_free_task(child); |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static void __init perf_event_init_all_cpus(void) |
| { |
| struct swevent_htable *swhash; |
| int cpu; |
| |
| for_each_possible_cpu(cpu) { |
| swhash = &per_cpu(swevent_htable, cpu); |
| mutex_init(&swhash->hlist_mutex); |
| INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); |
| } |
| } |
| |
| static void perf_event_init_cpu(int cpu) |
| { |
| struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); |
| |
| mutex_lock(&swhash->hlist_mutex); |
| if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { |
| struct swevent_hlist *hlist; |
| |
| hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); |
| WARN_ON(!hlist); |
| rcu_assign_pointer(swhash->swevent_hlist, hlist); |
| } |
| mutex_unlock(&swhash->hlist_mutex); |
| } |
| |
| #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE |
| static void __perf_event_exit_context(void *__info) |
| { |
| struct perf_event_context *ctx = __info; |
| struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); |
| struct perf_event *event; |
| |
| raw_spin_lock(&ctx->lock); |
| list_for_each_entry(event, &ctx->event_list, event_entry) |
| __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); |
| raw_spin_unlock(&ctx->lock); |
| } |
| |
| static void perf_event_exit_cpu_context(int cpu) |
| { |
| struct perf_event_context *ctx; |
| struct pmu *pmu; |
| int idx; |
| |
| idx = srcu_read_lock(&pmus_srcu); |
| list_for_each_entry_rcu(pmu, &pmus, entry) { |
| ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; |
| |
| mutex_lock(&ctx->mutex); |
| smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); |
| mutex_unlock(&ctx->mutex); |
| } |
| srcu_read_unlock(&pmus_srcu, idx); |
| } |
| |
| static void perf_event_exit_cpu(int cpu) |
| { |
| perf_event_exit_cpu_context(cpu); |
| } |
| #else |
| static inline void perf_event_exit_cpu(int cpu) { } |
| #endif |
| |
| static int |
| perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) |
| { |
| int cpu; |
| |
| for_each_online_cpu(cpu) |
| perf_event_exit_cpu(cpu); |
| |
| return NOTIFY_OK; |
| } |
| |
| /* |
| * Run the perf reboot notifier at the very last possible moment so that |
| * the generic watchdog code runs as long as possible. |
| */ |
| static struct notifier_block perf_reboot_notifier = { |
| .notifier_call = perf_reboot, |
| .priority = INT_MIN, |
| }; |
| |
| static int |
| perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) |
| { |
| unsigned int cpu = (long)hcpu; |
| |
| switch (action & ~CPU_TASKS_FROZEN) { |
| |
| case CPU_UP_PREPARE: |
| /* |
| * This must be done before the CPU comes alive, because the |
| * moment we can run tasks we can encounter (software) events. |
| * |
| * Specifically, someone can have inherited events on kthreadd |
| * or a pre-existing worker thread that gets re-bound. |
| */ |
| perf_event_init_cpu(cpu); |
| break; |
| |
| case CPU_DOWN_PREPARE: |
| /* |
| * This must be done before the CPU dies because after that an |
| * active event might want to IPI the CPU and that'll not work |
| * so great for dead CPUs. |
| * |
| * XXX smp_call_function_single() return -ENXIO without a warn |
| * so we could possibly deal with this. |
| * |
| * This is safe against new events arriving because |
| * sys_perf_event_open() serializes against hotplug using |
| * get_online_cpus(). |
| */ |
| perf_event_exit_cpu(cpu); |
| break; |
| default: |
| break; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| void __init perf_event_init(void) |
| { |
| int ret; |
| |
| idr_init(&pmu_idr); |
| |
| perf_event_init_all_cpus(); |
| init_srcu_struct(&pmus_srcu); |
| perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); |
| perf_pmu_register(&perf_cpu_clock, NULL, -1); |
| perf_pmu_register(&perf_task_clock, NULL, -1); |
| perf_tp_register(); |
| perf_cpu_notifier(perf_cpu_notify); |
| register_reboot_notifier(&perf_reboot_notifier); |
| |
| ret = init_hw_breakpoint(); |
| WARN(ret, "hw_breakpoint initialization failed with: %d", ret); |
| |
| /* |
| * Build time assertion that we keep the data_head at the intended |
| * location. IOW, validation we got the __reserved[] size right. |
| */ |
| BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) |
| != 1024); |
| } |
| |
| ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, |
| char *page) |
| { |
| struct perf_pmu_events_attr *pmu_attr = |
| container_of(attr, struct perf_pmu_events_attr, attr); |
| |
| if (pmu_attr->event_str) |
| return sprintf(page, "%s\n", pmu_attr->event_str); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(perf_event_sysfs_show); |
| |
| static int __init perf_event_sysfs_init(void) |
| { |
| struct pmu *pmu; |
| int ret; |
| |
| mutex_lock(&pmus_lock); |
| |
| ret = bus_register(&pmu_bus); |
| if (ret) |
| goto unlock; |
| |
| list_for_each_entry(pmu, &pmus, entry) { |
| if (!pmu->name || pmu->type < 0) |
| continue; |
| |
| ret = pmu_dev_alloc(pmu); |
| WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); |
| } |
| pmu_bus_running = 1; |
| ret = 0; |
| |
| unlock: |
| mutex_unlock(&pmus_lock); |
| |
| return ret; |
| } |
| device_initcall(perf_event_sysfs_init); |
| |
| #ifdef CONFIG_CGROUP_PERF |
| static struct cgroup_subsys_state * |
| perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) |
| { |
| struct perf_cgroup *jc; |
| |
| jc = kzalloc(sizeof(*jc), GFP_KERNEL); |
| if (!jc) |
| return ERR_PTR(-ENOMEM); |
| |
| jc->info = alloc_percpu(struct perf_cgroup_info); |
| if (!jc->info) { |
| kfree(jc); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| return &jc->css; |
| } |
| |
| static void perf_cgroup_css_free(struct cgroup_subsys_state *css) |
| { |
| struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); |
| |
| free_percpu(jc->info); |
| kfree(jc); |
| } |
| |
| static int __perf_cgroup_move(void *info) |
| { |
| struct task_struct *task = info; |
| rcu_read_lock(); |
| perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); |
| rcu_read_unlock(); |
| return 0; |
| } |
| |
| static void perf_cgroup_attach(struct cgroup_taskset *tset) |
| { |
| struct task_struct *task; |
| struct cgroup_subsys_state *css; |
| |
| cgroup_taskset_for_each(task, css, tset) |
| task_function_call(task, __perf_cgroup_move, task); |
| } |
| |
| struct cgroup_subsys perf_event_cgrp_subsys = { |
| .css_alloc = perf_cgroup_css_alloc, |
| .css_free = perf_cgroup_css_free, |
| .attach = perf_cgroup_attach, |
| }; |
| #endif /* CONFIG_CGROUP_PERF */ |