2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
52 #include <asm/irq_regs.h>
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id())
74 * Now that we're on right CPU with IRQs disabled, we can test
75 * if we hit the right task without races.
78 tfc->ret = -ESRCH; /* No such (running) process */
83 tfc->ret = tfc->func(tfc->info);
87 * task_function_call - call a function on the cpu on which a task runs
88 * @p: the task to evaluate
89 * @func: the function to be called
90 * @info: the function call argument
92 * Calls the function @func when the task is currently running. This might
93 * be on the current CPU, which just calls the function directly
95 * returns: @func return value, or
96 * -ESRCH - when the process isn't running
97 * -EAGAIN - when the process moved away
100 task_function_call(struct task_struct *p, remote_function_f func, void *info)
102 struct remote_function_call data = {
111 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
114 } while (ret == -EAGAIN);
120 * cpu_function_call - call a function on the cpu
121 * @func: the function to be called
122 * @info: the function call argument
124 * Calls the function @func on the remote cpu.
126 * returns: @func return value or -ENXIO when the cpu is offline
128 static int cpu_function_call(int cpu, remote_function_f func, void *info)
130 struct remote_function_call data = {
134 .ret = -ENXIO, /* No such CPU */
137 smp_call_function_single(cpu, remote_function, &data, 1);
142 static inline struct perf_cpu_context *
143 __get_cpu_context(struct perf_event_context *ctx)
145 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
148 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
149 struct perf_event_context *ctx)
151 raw_spin_lock(&cpuctx->ctx.lock);
153 raw_spin_lock(&ctx->lock);
156 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
157 struct perf_event_context *ctx)
160 raw_spin_unlock(&ctx->lock);
161 raw_spin_unlock(&cpuctx->ctx.lock);
164 #define TASK_TOMBSTONE ((void *)-1L)
166 static bool is_kernel_event(struct perf_event *event)
168 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
172 * On task ctx scheduling...
174 * When !ctx->nr_events a task context will not be scheduled. This means
175 * we can disable the scheduler hooks (for performance) without leaving
176 * pending task ctx state.
178 * This however results in two special cases:
180 * - removing the last event from a task ctx; this is relatively straight
181 * forward and is done in __perf_remove_from_context.
183 * - adding the first event to a task ctx; this is tricky because we cannot
184 * rely on ctx->is_active and therefore cannot use event_function_call().
185 * See perf_install_in_context().
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
191 struct perf_event_context *, void *);
193 struct event_function_struct {
194 struct perf_event *event;
199 static int event_function(void *info)
201 struct event_function_struct *efs = info;
202 struct perf_event *event = efs->event;
203 struct perf_event_context *ctx = event->ctx;
204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
205 struct perf_event_context *task_ctx = cpuctx->task_ctx;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx, task_ctx);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx->task != current) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx->is_active);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx != ctx);
235 WARN_ON_ONCE(&cpuctx->ctx != ctx);
238 efs->func(event, cpuctx, ctx, efs->data);
240 perf_ctx_unlock(cpuctx, task_ctx);
245 static void event_function_local(struct perf_event *event, event_f func, void *data)
247 struct event_function_struct efs = {
253 int ret = event_function(&efs);
257 static void event_function_call(struct perf_event *event, event_f func, void *data)
259 struct perf_event_context *ctx = event->ctx;
260 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
261 struct event_function_struct efs = {
267 if (!event->parent) {
269 * If this is a !child event, we must hold ctx::mutex to
270 * stabilize the the event->ctx relation. See
271 * perf_event_ctx_lock().
273 lockdep_assert_held(&ctx->mutex);
277 cpu_function_call(event->cpu, event_function, &efs);
281 if (task == TASK_TOMBSTONE)
285 if (!task_function_call(task, event_function, &efs))
288 raw_spin_lock_irq(&ctx->lock);
290 * Reload the task pointer, it might have been changed by
291 * a concurrent perf_event_context_sched_out().
294 if (task == TASK_TOMBSTONE) {
295 raw_spin_unlock_irq(&ctx->lock);
298 if (ctx->is_active) {
299 raw_spin_unlock_irq(&ctx->lock);
302 func(event, NULL, ctx, data);
303 raw_spin_unlock_irq(&ctx->lock);
306 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
307 PERF_FLAG_FD_OUTPUT |\
308 PERF_FLAG_PID_CGROUP |\
309 PERF_FLAG_FD_CLOEXEC)
312 * branch priv levels that need permission checks
314 #define PERF_SAMPLE_BRANCH_PERM_PLM \
315 (PERF_SAMPLE_BRANCH_KERNEL |\
316 PERF_SAMPLE_BRANCH_HV)
319 EVENT_FLEXIBLE = 0x1,
322 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
326 * perf_sched_events : >0 events exist
327 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
330 static void perf_sched_delayed(struct work_struct *work);
331 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
332 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
333 static DEFINE_MUTEX(perf_sched_mutex);
334 static atomic_t perf_sched_count;
336 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
337 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
338 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
340 static atomic_t nr_mmap_events __read_mostly;
341 static atomic_t nr_comm_events __read_mostly;
342 static atomic_t nr_task_events __read_mostly;
343 static atomic_t nr_freq_events __read_mostly;
344 static atomic_t nr_switch_events __read_mostly;
346 static LIST_HEAD(pmus);
347 static DEFINE_MUTEX(pmus_lock);
348 static struct srcu_struct pmus_srcu;
351 * perf event paranoia level:
352 * -1 - not paranoid at all
353 * 0 - disallow raw tracepoint access for unpriv
354 * 1 - disallow cpu events for unpriv
355 * 2 - disallow kernel profiling for unpriv
357 int sysctl_perf_event_paranoid __read_mostly = 2;
359 /* Minimum for 512 kiB + 1 user control page */
360 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
363 * max perf event sample rate
365 #define DEFAULT_MAX_SAMPLE_RATE 100000
366 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
367 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
369 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
371 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
372 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
374 static int perf_sample_allowed_ns __read_mostly =
375 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
377 static void update_perf_cpu_limits(void)
379 u64 tmp = perf_sample_period_ns;
381 tmp *= sysctl_perf_cpu_time_max_percent;
382 tmp = div_u64(tmp, 100);
386 WRITE_ONCE(perf_sample_allowed_ns, tmp);
389 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
391 int perf_proc_update_handler(struct ctl_table *table, int write,
392 void __user *buffer, size_t *lenp,
395 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
400 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
401 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
402 update_perf_cpu_limits();
407 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
409 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
410 void __user *buffer, size_t *lenp,
413 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
418 if (sysctl_perf_cpu_time_max_percent == 100 ||
419 sysctl_perf_cpu_time_max_percent == 0) {
421 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
422 WRITE_ONCE(perf_sample_allowed_ns, 0);
424 update_perf_cpu_limits();
431 * perf samples are done in some very critical code paths (NMIs).
432 * If they take too much CPU time, the system can lock up and not
433 * get any real work done. This will drop the sample rate when
434 * we detect that events are taking too long.
436 #define NR_ACCUMULATED_SAMPLES 128
437 static DEFINE_PER_CPU(u64, running_sample_length);
439 static u64 __report_avg;
440 static u64 __report_allowed;
442 static void perf_duration_warn(struct irq_work *w)
444 printk_ratelimited(KERN_WARNING
445 "perf: interrupt took too long (%lld > %lld), lowering "
446 "kernel.perf_event_max_sample_rate to %d\n",
447 __report_avg, __report_allowed,
448 sysctl_perf_event_sample_rate);
451 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
453 void perf_sample_event_took(u64 sample_len_ns)
455 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
463 /* Decay the counter by 1 average sample. */
464 running_len = __this_cpu_read(running_sample_length);
465 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
466 running_len += sample_len_ns;
467 __this_cpu_write(running_sample_length, running_len);
470 * Note: this will be biased artifically low until we have
471 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
472 * from having to maintain a count.
474 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
475 if (avg_len <= max_len)
478 __report_avg = avg_len;
479 __report_allowed = max_len;
482 * Compute a throttle threshold 25% below the current duration.
484 avg_len += avg_len / 4;
485 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
491 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
492 WRITE_ONCE(max_samples_per_tick, max);
494 sysctl_perf_event_sample_rate = max * HZ;
495 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
497 if (!irq_work_queue(&perf_duration_work)) {
498 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
499 "kernel.perf_event_max_sample_rate to %d\n",
500 __report_avg, __report_allowed,
501 sysctl_perf_event_sample_rate);
505 static atomic64_t perf_event_id;
507 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
508 enum event_type_t event_type);
510 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
511 enum event_type_t event_type,
512 struct task_struct *task);
514 static void update_context_time(struct perf_event_context *ctx);
515 static u64 perf_event_time(struct perf_event *event);
517 void __weak perf_event_print_debug(void) { }
519 extern __weak const char *perf_pmu_name(void)
524 static inline u64 perf_clock(void)
526 return local_clock();
529 static inline u64 perf_event_clock(struct perf_event *event)
531 return event->clock();
534 #ifdef CONFIG_CGROUP_PERF
537 perf_cgroup_match(struct perf_event *event)
539 struct perf_event_context *ctx = event->ctx;
540 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
542 /* @event doesn't care about cgroup */
546 /* wants specific cgroup scope but @cpuctx isn't associated with any */
551 * Cgroup scoping is recursive. An event enabled for a cgroup is
552 * also enabled for all its descendant cgroups. If @cpuctx's
553 * cgroup is a descendant of @event's (the test covers identity
554 * case), it's a match.
556 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
557 event->cgrp->css.cgroup);
560 static inline void perf_detach_cgroup(struct perf_event *event)
562 css_put(&event->cgrp->css);
566 static inline int is_cgroup_event(struct perf_event *event)
568 return event->cgrp != NULL;
571 static inline u64 perf_cgroup_event_time(struct perf_event *event)
573 struct perf_cgroup_info *t;
575 t = per_cpu_ptr(event->cgrp->info, event->cpu);
579 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
581 struct perf_cgroup_info *info;
586 info = this_cpu_ptr(cgrp->info);
588 info->time += now - info->timestamp;
589 info->timestamp = now;
592 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
594 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
596 __update_cgrp_time(cgrp_out);
599 static inline void update_cgrp_time_from_event(struct perf_event *event)
601 struct perf_cgroup *cgrp;
604 * ensure we access cgroup data only when needed and
605 * when we know the cgroup is pinned (css_get)
607 if (!is_cgroup_event(event))
610 cgrp = perf_cgroup_from_task(current, event->ctx);
612 * Do not update time when cgroup is not active
614 if (cgrp == event->cgrp)
615 __update_cgrp_time(event->cgrp);
619 perf_cgroup_set_timestamp(struct task_struct *task,
620 struct perf_event_context *ctx)
622 struct perf_cgroup *cgrp;
623 struct perf_cgroup_info *info;
626 * ctx->lock held by caller
627 * ensure we do not access cgroup data
628 * unless we have the cgroup pinned (css_get)
630 if (!task || !ctx->nr_cgroups)
633 cgrp = perf_cgroup_from_task(task, ctx);
634 info = this_cpu_ptr(cgrp->info);
635 info->timestamp = ctx->timestamp;
638 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
639 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
642 * reschedule events based on the cgroup constraint of task.
644 * mode SWOUT : schedule out everything
645 * mode SWIN : schedule in based on cgroup for next
647 static void perf_cgroup_switch(struct task_struct *task, int mode)
649 struct perf_cpu_context *cpuctx;
654 * disable interrupts to avoid geting nr_cgroup
655 * changes via __perf_event_disable(). Also
658 local_irq_save(flags);
661 * we reschedule only in the presence of cgroup
662 * constrained events.
665 list_for_each_entry_rcu(pmu, &pmus, entry) {
666 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
667 if (cpuctx->unique_pmu != pmu)
668 continue; /* ensure we process each cpuctx once */
671 * perf_cgroup_events says at least one
672 * context on this CPU has cgroup events.
674 * ctx->nr_cgroups reports the number of cgroup
675 * events for a context.
677 if (cpuctx->ctx.nr_cgroups > 0) {
678 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
679 perf_pmu_disable(cpuctx->ctx.pmu);
681 if (mode & PERF_CGROUP_SWOUT) {
682 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
684 * must not be done before ctxswout due
685 * to event_filter_match() in event_sched_out()
690 if (mode & PERF_CGROUP_SWIN) {
691 WARN_ON_ONCE(cpuctx->cgrp);
693 * set cgrp before ctxsw in to allow
694 * event_filter_match() to not have to pass
696 * we pass the cpuctx->ctx to perf_cgroup_from_task()
697 * because cgorup events are only per-cpu
699 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
700 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
702 perf_pmu_enable(cpuctx->ctx.pmu);
703 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
707 local_irq_restore(flags);
710 static inline void perf_cgroup_sched_out(struct task_struct *task,
711 struct task_struct *next)
713 struct perf_cgroup *cgrp1;
714 struct perf_cgroup *cgrp2 = NULL;
718 * we come here when we know perf_cgroup_events > 0
719 * we do not need to pass the ctx here because we know
720 * we are holding the rcu lock
722 cgrp1 = perf_cgroup_from_task(task, NULL);
723 cgrp2 = perf_cgroup_from_task(next, NULL);
726 * only schedule out current cgroup events if we know
727 * that we are switching to a different cgroup. Otherwise,
728 * do no touch the cgroup events.
731 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
736 static inline void perf_cgroup_sched_in(struct task_struct *prev,
737 struct task_struct *task)
739 struct perf_cgroup *cgrp1;
740 struct perf_cgroup *cgrp2 = NULL;
744 * we come here when we know perf_cgroup_events > 0
745 * we do not need to pass the ctx here because we know
746 * we are holding the rcu lock
748 cgrp1 = perf_cgroup_from_task(task, NULL);
749 cgrp2 = perf_cgroup_from_task(prev, NULL);
752 * only need to schedule in cgroup events if we are changing
753 * cgroup during ctxsw. Cgroup events were not scheduled
754 * out of ctxsw out if that was not the case.
757 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
762 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
763 struct perf_event_attr *attr,
764 struct perf_event *group_leader)
766 struct perf_cgroup *cgrp;
767 struct cgroup_subsys_state *css;
768 struct fd f = fdget(fd);
774 css = css_tryget_online_from_dir(f.file->f_path.dentry,
775 &perf_event_cgrp_subsys);
781 cgrp = container_of(css, struct perf_cgroup, css);
785 * all events in a group must monitor
786 * the same cgroup because a task belongs
787 * to only one perf cgroup at a time
789 if (group_leader && group_leader->cgrp != cgrp) {
790 perf_detach_cgroup(event);
799 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
801 struct perf_cgroup_info *t;
802 t = per_cpu_ptr(event->cgrp->info, event->cpu);
803 event->shadow_ctx_time = now - t->timestamp;
807 perf_cgroup_defer_enabled(struct perf_event *event)
810 * when the current task's perf cgroup does not match
811 * the event's, we need to remember to call the
812 * perf_mark_enable() function the first time a task with
813 * a matching perf cgroup is scheduled in.
815 if (is_cgroup_event(event) && !perf_cgroup_match(event))
816 event->cgrp_defer_enabled = 1;
820 perf_cgroup_mark_enabled(struct perf_event *event,
821 struct perf_event_context *ctx)
823 struct perf_event *sub;
824 u64 tstamp = perf_event_time(event);
826 if (!event->cgrp_defer_enabled)
829 event->cgrp_defer_enabled = 0;
831 event->tstamp_enabled = tstamp - event->total_time_enabled;
832 list_for_each_entry(sub, &event->sibling_list, group_entry) {
833 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
834 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
835 sub->cgrp_defer_enabled = 0;
839 #else /* !CONFIG_CGROUP_PERF */
842 perf_cgroup_match(struct perf_event *event)
847 static inline void perf_detach_cgroup(struct perf_event *event)
850 static inline int is_cgroup_event(struct perf_event *event)
855 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
860 static inline void update_cgrp_time_from_event(struct perf_event *event)
864 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
868 static inline void perf_cgroup_sched_out(struct task_struct *task,
869 struct task_struct *next)
873 static inline void perf_cgroup_sched_in(struct task_struct *prev,
874 struct task_struct *task)
878 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
879 struct perf_event_attr *attr,
880 struct perf_event *group_leader)
886 perf_cgroup_set_timestamp(struct task_struct *task,
887 struct perf_event_context *ctx)
892 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
897 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
901 static inline u64 perf_cgroup_event_time(struct perf_event *event)
907 perf_cgroup_defer_enabled(struct perf_event *event)
912 perf_cgroup_mark_enabled(struct perf_event *event,
913 struct perf_event_context *ctx)
919 * set default to be dependent on timer tick just
922 #define PERF_CPU_HRTIMER (1000 / HZ)
924 * function must be called with interrupts disbled
926 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
928 struct perf_cpu_context *cpuctx;
931 WARN_ON(!irqs_disabled());
933 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
934 rotations = perf_rotate_context(cpuctx);
936 raw_spin_lock(&cpuctx->hrtimer_lock);
938 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
940 cpuctx->hrtimer_active = 0;
941 raw_spin_unlock(&cpuctx->hrtimer_lock);
943 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
946 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
948 struct hrtimer *timer = &cpuctx->hrtimer;
949 struct pmu *pmu = cpuctx->ctx.pmu;
952 /* no multiplexing needed for SW PMU */
953 if (pmu->task_ctx_nr == perf_sw_context)
957 * check default is sane, if not set then force to
958 * default interval (1/tick)
960 interval = pmu->hrtimer_interval_ms;
962 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
964 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
966 raw_spin_lock_init(&cpuctx->hrtimer_lock);
967 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
968 timer->function = perf_mux_hrtimer_handler;
971 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
973 struct hrtimer *timer = &cpuctx->hrtimer;
974 struct pmu *pmu = cpuctx->ctx.pmu;
978 if (pmu->task_ctx_nr == perf_sw_context)
981 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
982 if (!cpuctx->hrtimer_active) {
983 cpuctx->hrtimer_active = 1;
984 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
985 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
987 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
992 void perf_pmu_disable(struct pmu *pmu)
994 int *count = this_cpu_ptr(pmu->pmu_disable_count);
996 pmu->pmu_disable(pmu);
999 void perf_pmu_enable(struct pmu *pmu)
1001 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1003 pmu->pmu_enable(pmu);
1006 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1009 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1010 * perf_event_task_tick() are fully serialized because they're strictly cpu
1011 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1012 * disabled, while perf_event_task_tick is called from IRQ context.
1014 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1016 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1018 WARN_ON(!irqs_disabled());
1020 WARN_ON(!list_empty(&ctx->active_ctx_list));
1022 list_add(&ctx->active_ctx_list, head);
1025 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1027 WARN_ON(!irqs_disabled());
1029 WARN_ON(list_empty(&ctx->active_ctx_list));
1031 list_del_init(&ctx->active_ctx_list);
1034 static void get_ctx(struct perf_event_context *ctx)
1036 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1039 static void free_ctx(struct rcu_head *head)
1041 struct perf_event_context *ctx;
1043 ctx = container_of(head, struct perf_event_context, rcu_head);
1044 kfree(ctx->task_ctx_data);
1048 static void put_ctx(struct perf_event_context *ctx)
1050 if (atomic_dec_and_test(&ctx->refcount)) {
1051 if (ctx->parent_ctx)
1052 put_ctx(ctx->parent_ctx);
1053 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1054 put_task_struct(ctx->task);
1055 call_rcu(&ctx->rcu_head, free_ctx);
1060 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1061 * perf_pmu_migrate_context() we need some magic.
1063 * Those places that change perf_event::ctx will hold both
1064 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1066 * Lock ordering is by mutex address. There are two other sites where
1067 * perf_event_context::mutex nests and those are:
1069 * - perf_event_exit_task_context() [ child , 0 ]
1070 * perf_event_exit_event()
1071 * put_event() [ parent, 1 ]
1073 * - perf_event_init_context() [ parent, 0 ]
1074 * inherit_task_group()
1077 * perf_event_alloc()
1079 * perf_try_init_event() [ child , 1 ]
1081 * While it appears there is an obvious deadlock here -- the parent and child
1082 * nesting levels are inverted between the two. This is in fact safe because
1083 * life-time rules separate them. That is an exiting task cannot fork, and a
1084 * spawning task cannot (yet) exit.
1086 * But remember that that these are parent<->child context relations, and
1087 * migration does not affect children, therefore these two orderings should not
1090 * The change in perf_event::ctx does not affect children (as claimed above)
1091 * because the sys_perf_event_open() case will install a new event and break
1092 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1093 * concerned with cpuctx and that doesn't have children.
1095 * The places that change perf_event::ctx will issue:
1097 * perf_remove_from_context();
1098 * synchronize_rcu();
1099 * perf_install_in_context();
1101 * to affect the change. The remove_from_context() + synchronize_rcu() should
1102 * quiesce the event, after which we can install it in the new location. This
1103 * means that only external vectors (perf_fops, prctl) can perturb the event
1104 * while in transit. Therefore all such accessors should also acquire
1105 * perf_event_context::mutex to serialize against this.
1107 * However; because event->ctx can change while we're waiting to acquire
1108 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1113 * task_struct::perf_event_mutex
1114 * perf_event_context::mutex
1115 * perf_event::child_mutex;
1116 * perf_event_context::lock
1117 * perf_event::mmap_mutex
1120 static struct perf_event_context *
1121 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1123 struct perf_event_context *ctx;
1127 ctx = ACCESS_ONCE(event->ctx);
1128 if (!atomic_inc_not_zero(&ctx->refcount)) {
1134 mutex_lock_nested(&ctx->mutex, nesting);
1135 if (event->ctx != ctx) {
1136 mutex_unlock(&ctx->mutex);
1144 static inline struct perf_event_context *
1145 perf_event_ctx_lock(struct perf_event *event)
1147 return perf_event_ctx_lock_nested(event, 0);
1150 static void perf_event_ctx_unlock(struct perf_event *event,
1151 struct perf_event_context *ctx)
1153 mutex_unlock(&ctx->mutex);
1158 * This must be done under the ctx->lock, such as to serialize against
1159 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1160 * calling scheduler related locks and ctx->lock nests inside those.
1162 static __must_check struct perf_event_context *
1163 unclone_ctx(struct perf_event_context *ctx)
1165 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1167 lockdep_assert_held(&ctx->lock);
1170 ctx->parent_ctx = NULL;
1176 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1179 * only top level events have the pid namespace they were created in
1182 event = event->parent;
1184 return task_tgid_nr_ns(p, event->ns);
1187 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1190 * only top level events have the pid namespace they were created in
1193 event = event->parent;
1195 return task_pid_nr_ns(p, event->ns);
1199 * If we inherit events we want to return the parent event id
1202 static u64 primary_event_id(struct perf_event *event)
1207 id = event->parent->id;
1213 * Get the perf_event_context for a task and lock it.
1215 * This has to cope with with the fact that until it is locked,
1216 * the context could get moved to another task.
1218 static struct perf_event_context *
1219 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1221 struct perf_event_context *ctx;
1225 * One of the few rules of preemptible RCU is that one cannot do
1226 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1227 * part of the read side critical section was irqs-enabled -- see
1228 * rcu_read_unlock_special().
1230 * Since ctx->lock nests under rq->lock we must ensure the entire read
1231 * side critical section has interrupts disabled.
1233 local_irq_save(*flags);
1235 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1238 * If this context is a clone of another, it might
1239 * get swapped for another underneath us by
1240 * perf_event_task_sched_out, though the
1241 * rcu_read_lock() protects us from any context
1242 * getting freed. Lock the context and check if it
1243 * got swapped before we could get the lock, and retry
1244 * if so. If we locked the right context, then it
1245 * can't get swapped on us any more.
1247 raw_spin_lock(&ctx->lock);
1248 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1249 raw_spin_unlock(&ctx->lock);
1251 local_irq_restore(*flags);
1255 if (ctx->task == TASK_TOMBSTONE ||
1256 !atomic_inc_not_zero(&ctx->refcount)) {
1257 raw_spin_unlock(&ctx->lock);
1260 WARN_ON_ONCE(ctx->task != task);
1265 local_irq_restore(*flags);
1270 * Get the context for a task and increment its pin_count so it
1271 * can't get swapped to another task. This also increments its
1272 * reference count so that the context can't get freed.
1274 static struct perf_event_context *
1275 perf_pin_task_context(struct task_struct *task, int ctxn)
1277 struct perf_event_context *ctx;
1278 unsigned long flags;
1280 ctx = perf_lock_task_context(task, ctxn, &flags);
1283 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1288 static void perf_unpin_context(struct perf_event_context *ctx)
1290 unsigned long flags;
1292 raw_spin_lock_irqsave(&ctx->lock, flags);
1294 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1298 * Update the record of the current time in a context.
1300 static void update_context_time(struct perf_event_context *ctx)
1302 u64 now = perf_clock();
1304 ctx->time += now - ctx->timestamp;
1305 ctx->timestamp = now;
1308 static u64 perf_event_time(struct perf_event *event)
1310 struct perf_event_context *ctx = event->ctx;
1312 if (is_cgroup_event(event))
1313 return perf_cgroup_event_time(event);
1315 return ctx ? ctx->time : 0;
1319 * Update the total_time_enabled and total_time_running fields for a event.
1321 static void update_event_times(struct perf_event *event)
1323 struct perf_event_context *ctx = event->ctx;
1326 lockdep_assert_held(&ctx->lock);
1328 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1329 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1333 * in cgroup mode, time_enabled represents
1334 * the time the event was enabled AND active
1335 * tasks were in the monitored cgroup. This is
1336 * independent of the activity of the context as
1337 * there may be a mix of cgroup and non-cgroup events.
1339 * That is why we treat cgroup events differently
1342 if (is_cgroup_event(event))
1343 run_end = perf_cgroup_event_time(event);
1344 else if (ctx->is_active)
1345 run_end = ctx->time;
1347 run_end = event->tstamp_stopped;
1349 event->total_time_enabled = run_end - event->tstamp_enabled;
1351 if (event->state == PERF_EVENT_STATE_INACTIVE)
1352 run_end = event->tstamp_stopped;
1354 run_end = perf_event_time(event);
1356 event->total_time_running = run_end - event->tstamp_running;
1361 * Update total_time_enabled and total_time_running for all events in a group.
1363 static void update_group_times(struct perf_event *leader)
1365 struct perf_event *event;
1367 update_event_times(leader);
1368 list_for_each_entry(event, &leader->sibling_list, group_entry)
1369 update_event_times(event);
1372 static struct list_head *
1373 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1375 if (event->attr.pinned)
1376 return &ctx->pinned_groups;
1378 return &ctx->flexible_groups;
1382 * Add a event from the lists for its context.
1383 * Must be called with ctx->mutex and ctx->lock held.
1386 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1388 lockdep_assert_held(&ctx->lock);
1390 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1391 event->attach_state |= PERF_ATTACH_CONTEXT;
1394 * If we're a stand alone event or group leader, we go to the context
1395 * list, group events are kept attached to the group so that
1396 * perf_group_detach can, at all times, locate all siblings.
1398 if (event->group_leader == event) {
1399 struct list_head *list;
1401 if (is_software_event(event))
1402 event->group_flags |= PERF_GROUP_SOFTWARE;
1404 list = ctx_group_list(event, ctx);
1405 list_add_tail(&event->group_entry, list);
1408 if (is_cgroup_event(event))
1411 list_add_rcu(&event->event_entry, &ctx->event_list);
1413 if (event->attr.inherit_stat)
1420 * Initialize event state based on the perf_event_attr::disabled.
1422 static inline void perf_event__state_init(struct perf_event *event)
1424 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1425 PERF_EVENT_STATE_INACTIVE;
1428 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1430 int entry = sizeof(u64); /* value */
1434 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1435 size += sizeof(u64);
1437 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1438 size += sizeof(u64);
1440 if (event->attr.read_format & PERF_FORMAT_ID)
1441 entry += sizeof(u64);
1443 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1445 size += sizeof(u64);
1449 event->read_size = size;
1452 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1454 struct perf_sample_data *data;
1457 if (sample_type & PERF_SAMPLE_IP)
1458 size += sizeof(data->ip);
1460 if (sample_type & PERF_SAMPLE_ADDR)
1461 size += sizeof(data->addr);
1463 if (sample_type & PERF_SAMPLE_PERIOD)
1464 size += sizeof(data->period);
1466 if (sample_type & PERF_SAMPLE_WEIGHT)
1467 size += sizeof(data->weight);
1469 if (sample_type & PERF_SAMPLE_READ)
1470 size += event->read_size;
1472 if (sample_type & PERF_SAMPLE_DATA_SRC)
1473 size += sizeof(data->data_src.val);
1475 if (sample_type & PERF_SAMPLE_TRANSACTION)
1476 size += sizeof(data->txn);
1478 event->header_size = size;
1482 * Called at perf_event creation and when events are attached/detached from a
1485 static void perf_event__header_size(struct perf_event *event)
1487 __perf_event_read_size(event,
1488 event->group_leader->nr_siblings);
1489 __perf_event_header_size(event, event->attr.sample_type);
1492 static void perf_event__id_header_size(struct perf_event *event)
1494 struct perf_sample_data *data;
1495 u64 sample_type = event->attr.sample_type;
1498 if (sample_type & PERF_SAMPLE_TID)
1499 size += sizeof(data->tid_entry);
1501 if (sample_type & PERF_SAMPLE_TIME)
1502 size += sizeof(data->time);
1504 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1505 size += sizeof(data->id);
1507 if (sample_type & PERF_SAMPLE_ID)
1508 size += sizeof(data->id);
1510 if (sample_type & PERF_SAMPLE_STREAM_ID)
1511 size += sizeof(data->stream_id);
1513 if (sample_type & PERF_SAMPLE_CPU)
1514 size += sizeof(data->cpu_entry);
1516 event->id_header_size = size;
1519 static bool perf_event_validate_size(struct perf_event *event)
1522 * The values computed here will be over-written when we actually
1525 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1526 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1527 perf_event__id_header_size(event);
1530 * Sum the lot; should not exceed the 64k limit we have on records.
1531 * Conservative limit to allow for callchains and other variable fields.
1533 if (event->read_size + event->header_size +
1534 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1540 static void perf_group_attach(struct perf_event *event)
1542 struct perf_event *group_leader = event->group_leader, *pos;
1545 * We can have double attach due to group movement in perf_event_open.
1547 if (event->attach_state & PERF_ATTACH_GROUP)
1550 event->attach_state |= PERF_ATTACH_GROUP;
1552 if (group_leader == event)
1555 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1557 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1558 !is_software_event(event))
1559 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1561 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1562 group_leader->nr_siblings++;
1564 perf_event__header_size(group_leader);
1566 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1567 perf_event__header_size(pos);
1571 * Remove a event from the lists for its context.
1572 * Must be called with ctx->mutex and ctx->lock held.
1575 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1577 struct perf_cpu_context *cpuctx;
1579 WARN_ON_ONCE(event->ctx != ctx);
1580 lockdep_assert_held(&ctx->lock);
1583 * We can have double detach due to exit/hot-unplug + close.
1585 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1588 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1590 if (is_cgroup_event(event)) {
1593 * Because cgroup events are always per-cpu events, this will
1594 * always be called from the right CPU.
1596 cpuctx = __get_cpu_context(ctx);
1598 * If there are no more cgroup events then clear cgrp to avoid
1599 * stale pointer in update_cgrp_time_from_cpuctx().
1601 if (!ctx->nr_cgroups)
1602 cpuctx->cgrp = NULL;
1606 if (event->attr.inherit_stat)
1609 list_del_rcu(&event->event_entry);
1611 if (event->group_leader == event)
1612 list_del_init(&event->group_entry);
1614 update_group_times(event);
1617 * If event was in error state, then keep it
1618 * that way, otherwise bogus counts will be
1619 * returned on read(). The only way to get out
1620 * of error state is by explicit re-enabling
1623 if (event->state > PERF_EVENT_STATE_OFF)
1624 event->state = PERF_EVENT_STATE_OFF;
1629 static void perf_group_detach(struct perf_event *event)
1631 struct perf_event *sibling, *tmp;
1632 struct list_head *list = NULL;
1635 * We can have double detach due to exit/hot-unplug + close.
1637 if (!(event->attach_state & PERF_ATTACH_GROUP))
1640 event->attach_state &= ~PERF_ATTACH_GROUP;
1643 * If this is a sibling, remove it from its group.
1645 if (event->group_leader != event) {
1646 list_del_init(&event->group_entry);
1647 event->group_leader->nr_siblings--;
1651 if (!list_empty(&event->group_entry))
1652 list = &event->group_entry;
1655 * If this was a group event with sibling events then
1656 * upgrade the siblings to singleton events by adding them
1657 * to whatever list we are on.
1659 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1661 list_move_tail(&sibling->group_entry, list);
1662 sibling->group_leader = sibling;
1664 /* Inherit group flags from the previous leader */
1665 sibling->group_flags = event->group_flags;
1667 WARN_ON_ONCE(sibling->ctx != event->ctx);
1671 perf_event__header_size(event->group_leader);
1673 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1674 perf_event__header_size(tmp);
1677 static bool is_orphaned_event(struct perf_event *event)
1679 return event->state == PERF_EVENT_STATE_DEAD;
1682 static inline int pmu_filter_match(struct perf_event *event)
1684 struct pmu *pmu = event->pmu;
1685 return pmu->filter_match ? pmu->filter_match(event) : 1;
1689 event_filter_match(struct perf_event *event)
1691 return (event->cpu == -1 || event->cpu == smp_processor_id())
1692 && perf_cgroup_match(event) && pmu_filter_match(event);
1696 event_sched_out(struct perf_event *event,
1697 struct perf_cpu_context *cpuctx,
1698 struct perf_event_context *ctx)
1700 u64 tstamp = perf_event_time(event);
1703 WARN_ON_ONCE(event->ctx != ctx);
1704 lockdep_assert_held(&ctx->lock);
1707 * An event which could not be activated because of
1708 * filter mismatch still needs to have its timings
1709 * maintained, otherwise bogus information is return
1710 * via read() for time_enabled, time_running:
1712 if (event->state == PERF_EVENT_STATE_INACTIVE
1713 && !event_filter_match(event)) {
1714 delta = tstamp - event->tstamp_stopped;
1715 event->tstamp_running += delta;
1716 event->tstamp_stopped = tstamp;
1719 if (event->state != PERF_EVENT_STATE_ACTIVE)
1722 perf_pmu_disable(event->pmu);
1724 event->tstamp_stopped = tstamp;
1725 event->pmu->del(event, 0);
1727 event->state = PERF_EVENT_STATE_INACTIVE;
1728 if (event->pending_disable) {
1729 event->pending_disable = 0;
1730 event->state = PERF_EVENT_STATE_OFF;
1733 if (!is_software_event(event))
1734 cpuctx->active_oncpu--;
1735 if (!--ctx->nr_active)
1736 perf_event_ctx_deactivate(ctx);
1737 if (event->attr.freq && event->attr.sample_freq)
1739 if (event->attr.exclusive || !cpuctx->active_oncpu)
1740 cpuctx->exclusive = 0;
1742 perf_pmu_enable(event->pmu);
1746 group_sched_out(struct perf_event *group_event,
1747 struct perf_cpu_context *cpuctx,
1748 struct perf_event_context *ctx)
1750 struct perf_event *event;
1751 int state = group_event->state;
1753 event_sched_out(group_event, cpuctx, ctx);
1756 * Schedule out siblings (if any):
1758 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1759 event_sched_out(event, cpuctx, ctx);
1761 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1762 cpuctx->exclusive = 0;
1765 #define DETACH_GROUP 0x01UL
1768 * Cross CPU call to remove a performance event
1770 * We disable the event on the hardware level first. After that we
1771 * remove it from the context list.
1774 __perf_remove_from_context(struct perf_event *event,
1775 struct perf_cpu_context *cpuctx,
1776 struct perf_event_context *ctx,
1779 unsigned long flags = (unsigned long)info;
1781 event_sched_out(event, cpuctx, ctx);
1782 if (flags & DETACH_GROUP)
1783 perf_group_detach(event);
1784 list_del_event(event, ctx);
1786 if (!ctx->nr_events && ctx->is_active) {
1789 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1790 cpuctx->task_ctx = NULL;
1796 * Remove the event from a task's (or a CPU's) list of events.
1798 * If event->ctx is a cloned context, callers must make sure that
1799 * every task struct that event->ctx->task could possibly point to
1800 * remains valid. This is OK when called from perf_release since
1801 * that only calls us on the top-level context, which can't be a clone.
1802 * When called from perf_event_exit_task, it's OK because the
1803 * context has been detached from its task.
1805 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1807 lockdep_assert_held(&event->ctx->mutex);
1809 event_function_call(event, __perf_remove_from_context, (void *)flags);
1813 * Cross CPU call to disable a performance event
1815 static void __perf_event_disable(struct perf_event *event,
1816 struct perf_cpu_context *cpuctx,
1817 struct perf_event_context *ctx,
1820 if (event->state < PERF_EVENT_STATE_INACTIVE)
1823 update_context_time(ctx);
1824 update_cgrp_time_from_event(event);
1825 update_group_times(event);
1826 if (event == event->group_leader)
1827 group_sched_out(event, cpuctx, ctx);
1829 event_sched_out(event, cpuctx, ctx);
1830 event->state = PERF_EVENT_STATE_OFF;
1836 * If event->ctx is a cloned context, callers must make sure that
1837 * every task struct that event->ctx->task could possibly point to
1838 * remains valid. This condition is satisifed when called through
1839 * perf_event_for_each_child or perf_event_for_each because they
1840 * hold the top-level event's child_mutex, so any descendant that
1841 * goes to exit will block in perf_event_exit_event().
1843 * When called from perf_pending_event it's OK because event->ctx
1844 * is the current context on this CPU and preemption is disabled,
1845 * hence we can't get into perf_event_task_sched_out for this context.
1847 static void _perf_event_disable(struct perf_event *event)
1849 struct perf_event_context *ctx = event->ctx;
1851 raw_spin_lock_irq(&ctx->lock);
1852 if (event->state <= PERF_EVENT_STATE_OFF) {
1853 raw_spin_unlock_irq(&ctx->lock);
1856 raw_spin_unlock_irq(&ctx->lock);
1858 event_function_call(event, __perf_event_disable, NULL);
1861 void perf_event_disable_local(struct perf_event *event)
1863 event_function_local(event, __perf_event_disable, NULL);
1867 * Strictly speaking kernel users cannot create groups and therefore this
1868 * interface does not need the perf_event_ctx_lock() magic.
1870 void perf_event_disable(struct perf_event *event)
1872 struct perf_event_context *ctx;
1874 ctx = perf_event_ctx_lock(event);
1875 _perf_event_disable(event);
1876 perf_event_ctx_unlock(event, ctx);
1878 EXPORT_SYMBOL_GPL(perf_event_disable);
1880 static void perf_set_shadow_time(struct perf_event *event,
1881 struct perf_event_context *ctx,
1885 * use the correct time source for the time snapshot
1887 * We could get by without this by leveraging the
1888 * fact that to get to this function, the caller
1889 * has most likely already called update_context_time()
1890 * and update_cgrp_time_xx() and thus both timestamp
1891 * are identical (or very close). Given that tstamp is,
1892 * already adjusted for cgroup, we could say that:
1893 * tstamp - ctx->timestamp
1895 * tstamp - cgrp->timestamp.
1897 * Then, in perf_output_read(), the calculation would
1898 * work with no changes because:
1899 * - event is guaranteed scheduled in
1900 * - no scheduled out in between
1901 * - thus the timestamp would be the same
1903 * But this is a bit hairy.
1905 * So instead, we have an explicit cgroup call to remain
1906 * within the time time source all along. We believe it
1907 * is cleaner and simpler to understand.
1909 if (is_cgroup_event(event))
1910 perf_cgroup_set_shadow_time(event, tstamp);
1912 event->shadow_ctx_time = tstamp - ctx->timestamp;
1915 #define MAX_INTERRUPTS (~0ULL)
1917 static void perf_log_throttle(struct perf_event *event, int enable);
1918 static void perf_log_itrace_start(struct perf_event *event);
1921 event_sched_in(struct perf_event *event,
1922 struct perf_cpu_context *cpuctx,
1923 struct perf_event_context *ctx)
1925 u64 tstamp = perf_event_time(event);
1928 lockdep_assert_held(&ctx->lock);
1930 if (event->state <= PERF_EVENT_STATE_OFF)
1933 WRITE_ONCE(event->oncpu, smp_processor_id());
1935 * Order event::oncpu write to happen before the ACTIVE state
1939 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
1942 * Unthrottle events, since we scheduled we might have missed several
1943 * ticks already, also for a heavily scheduling task there is little
1944 * guarantee it'll get a tick in a timely manner.
1946 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1947 perf_log_throttle(event, 1);
1948 event->hw.interrupts = 0;
1952 * The new state must be visible before we turn it on in the hardware:
1956 perf_pmu_disable(event->pmu);
1958 perf_set_shadow_time(event, ctx, tstamp);
1960 perf_log_itrace_start(event);
1962 if (event->pmu->add(event, PERF_EF_START)) {
1963 event->state = PERF_EVENT_STATE_INACTIVE;
1969 event->tstamp_running += tstamp - event->tstamp_stopped;
1971 if (!is_software_event(event))
1972 cpuctx->active_oncpu++;
1973 if (!ctx->nr_active++)
1974 perf_event_ctx_activate(ctx);
1975 if (event->attr.freq && event->attr.sample_freq)
1978 if (event->attr.exclusive)
1979 cpuctx->exclusive = 1;
1982 perf_pmu_enable(event->pmu);
1988 group_sched_in(struct perf_event *group_event,
1989 struct perf_cpu_context *cpuctx,
1990 struct perf_event_context *ctx)
1992 struct perf_event *event, *partial_group = NULL;
1993 struct pmu *pmu = ctx->pmu;
1994 u64 now = ctx->time;
1995 bool simulate = false;
1997 if (group_event->state == PERF_EVENT_STATE_OFF)
2000 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2002 if (event_sched_in(group_event, cpuctx, ctx)) {
2003 pmu->cancel_txn(pmu);
2004 perf_mux_hrtimer_restart(cpuctx);
2009 * Schedule in siblings as one group (if any):
2011 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2012 if (event_sched_in(event, cpuctx, ctx)) {
2013 partial_group = event;
2018 if (!pmu->commit_txn(pmu))
2023 * Groups can be scheduled in as one unit only, so undo any
2024 * partial group before returning:
2025 * The events up to the failed event are scheduled out normally,
2026 * tstamp_stopped will be updated.
2028 * The failed events and the remaining siblings need to have
2029 * their timings updated as if they had gone thru event_sched_in()
2030 * and event_sched_out(). This is required to get consistent timings
2031 * across the group. This also takes care of the case where the group
2032 * could never be scheduled by ensuring tstamp_stopped is set to mark
2033 * the time the event was actually stopped, such that time delta
2034 * calculation in update_event_times() is correct.
2036 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2037 if (event == partial_group)
2041 event->tstamp_running += now - event->tstamp_stopped;
2042 event->tstamp_stopped = now;
2044 event_sched_out(event, cpuctx, ctx);
2047 event_sched_out(group_event, cpuctx, ctx);
2049 pmu->cancel_txn(pmu);
2051 perf_mux_hrtimer_restart(cpuctx);
2057 * Work out whether we can put this event group on the CPU now.
2059 static int group_can_go_on(struct perf_event *event,
2060 struct perf_cpu_context *cpuctx,
2064 * Groups consisting entirely of software events can always go on.
2066 if (event->group_flags & PERF_GROUP_SOFTWARE)
2069 * If an exclusive group is already on, no other hardware
2072 if (cpuctx->exclusive)
2075 * If this group is exclusive and there are already
2076 * events on the CPU, it can't go on.
2078 if (event->attr.exclusive && cpuctx->active_oncpu)
2081 * Otherwise, try to add it if all previous groups were able
2087 static void add_event_to_ctx(struct perf_event *event,
2088 struct perf_event_context *ctx)
2090 u64 tstamp = perf_event_time(event);
2092 list_add_event(event, ctx);
2093 perf_group_attach(event);
2094 event->tstamp_enabled = tstamp;
2095 event->tstamp_running = tstamp;
2096 event->tstamp_stopped = tstamp;
2099 static void ctx_sched_out(struct perf_event_context *ctx,
2100 struct perf_cpu_context *cpuctx,
2101 enum event_type_t event_type);
2103 ctx_sched_in(struct perf_event_context *ctx,
2104 struct perf_cpu_context *cpuctx,
2105 enum event_type_t event_type,
2106 struct task_struct *task);
2108 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2109 struct perf_event_context *ctx)
2111 if (!cpuctx->task_ctx)
2114 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2117 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2120 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2121 struct perf_event_context *ctx,
2122 struct task_struct *task)
2124 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2126 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2127 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2129 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2132 static void ctx_resched(struct perf_cpu_context *cpuctx,
2133 struct perf_event_context *task_ctx)
2135 perf_pmu_disable(cpuctx->ctx.pmu);
2137 task_ctx_sched_out(cpuctx, task_ctx);
2138 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2139 perf_event_sched_in(cpuctx, task_ctx, current);
2140 perf_pmu_enable(cpuctx->ctx.pmu);
2144 * Cross CPU call to install and enable a performance event
2146 * Very similar to remote_function() + event_function() but cannot assume that
2147 * things like ctx->is_active and cpuctx->task_ctx are set.
2149 static int __perf_install_in_context(void *info)
2151 struct perf_event *event = info;
2152 struct perf_event_context *ctx = event->ctx;
2153 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2154 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2155 bool activate = true;
2158 raw_spin_lock(&cpuctx->ctx.lock);
2160 raw_spin_lock(&ctx->lock);
2163 /* If we're on the wrong CPU, try again */
2164 if (task_cpu(ctx->task) != smp_processor_id()) {
2170 * If we're on the right CPU, see if the task we target is
2171 * current, if not we don't have to activate the ctx, a future
2172 * context switch will do that for us.
2174 if (ctx->task != current)
2177 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2179 } else if (task_ctx) {
2180 raw_spin_lock(&task_ctx->lock);
2184 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2185 add_event_to_ctx(event, ctx);
2186 ctx_resched(cpuctx, task_ctx);
2188 add_event_to_ctx(event, ctx);
2192 perf_ctx_unlock(cpuctx, task_ctx);
2198 * Attach a performance event to a context.
2200 * Very similar to event_function_call, see comment there.
2203 perf_install_in_context(struct perf_event_context *ctx,
2204 struct perf_event *event,
2207 struct task_struct *task = READ_ONCE(ctx->task);
2209 lockdep_assert_held(&ctx->mutex);
2212 if (event->cpu != -1)
2216 cpu_function_call(cpu, __perf_install_in_context, event);
2221 * Should not happen, we validate the ctx is still alive before calling.
2223 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2227 * Installing events is tricky because we cannot rely on ctx->is_active
2228 * to be set in case this is the nr_events 0 -> 1 transition.
2232 * Cannot use task_function_call() because we need to run on the task's
2233 * CPU regardless of whether its current or not.
2235 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2238 raw_spin_lock_irq(&ctx->lock);
2240 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2242 * Cannot happen because we already checked above (which also
2243 * cannot happen), and we hold ctx->mutex, which serializes us
2244 * against perf_event_exit_task_context().
2246 raw_spin_unlock_irq(&ctx->lock);
2249 raw_spin_unlock_irq(&ctx->lock);
2251 * Since !ctx->is_active doesn't mean anything, we must IPI
2258 * Put a event into inactive state and update time fields.
2259 * Enabling the leader of a group effectively enables all
2260 * the group members that aren't explicitly disabled, so we
2261 * have to update their ->tstamp_enabled also.
2262 * Note: this works for group members as well as group leaders
2263 * since the non-leader members' sibling_lists will be empty.
2265 static void __perf_event_mark_enabled(struct perf_event *event)
2267 struct perf_event *sub;
2268 u64 tstamp = perf_event_time(event);
2270 event->state = PERF_EVENT_STATE_INACTIVE;
2271 event->tstamp_enabled = tstamp - event->total_time_enabled;
2272 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2273 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2274 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2279 * Cross CPU call to enable a performance event
2281 static void __perf_event_enable(struct perf_event *event,
2282 struct perf_cpu_context *cpuctx,
2283 struct perf_event_context *ctx,
2286 struct perf_event *leader = event->group_leader;
2287 struct perf_event_context *task_ctx;
2289 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2290 event->state <= PERF_EVENT_STATE_ERROR)
2294 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2296 __perf_event_mark_enabled(event);
2298 if (!ctx->is_active)
2301 if (!event_filter_match(event)) {
2302 if (is_cgroup_event(event))
2303 perf_cgroup_defer_enabled(event);
2304 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2309 * If the event is in a group and isn't the group leader,
2310 * then don't put it on unless the group is on.
2312 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2313 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2317 task_ctx = cpuctx->task_ctx;
2319 WARN_ON_ONCE(task_ctx != ctx);
2321 ctx_resched(cpuctx, task_ctx);
2327 * If event->ctx is a cloned context, callers must make sure that
2328 * every task struct that event->ctx->task could possibly point to
2329 * remains valid. This condition is satisfied when called through
2330 * perf_event_for_each_child or perf_event_for_each as described
2331 * for perf_event_disable.
2333 static void _perf_event_enable(struct perf_event *event)
2335 struct perf_event_context *ctx = event->ctx;
2337 raw_spin_lock_irq(&ctx->lock);
2338 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2339 event->state < PERF_EVENT_STATE_ERROR) {
2340 raw_spin_unlock_irq(&ctx->lock);
2345 * If the event is in error state, clear that first.
2347 * That way, if we see the event in error state below, we know that it
2348 * has gone back into error state, as distinct from the task having
2349 * been scheduled away before the cross-call arrived.
2351 if (event->state == PERF_EVENT_STATE_ERROR)
2352 event->state = PERF_EVENT_STATE_OFF;
2353 raw_spin_unlock_irq(&ctx->lock);
2355 event_function_call(event, __perf_event_enable, NULL);
2359 * See perf_event_disable();
2361 void perf_event_enable(struct perf_event *event)
2363 struct perf_event_context *ctx;
2365 ctx = perf_event_ctx_lock(event);
2366 _perf_event_enable(event);
2367 perf_event_ctx_unlock(event, ctx);
2369 EXPORT_SYMBOL_GPL(perf_event_enable);
2371 struct stop_event_data {
2372 struct perf_event *event;
2373 unsigned int restart;
2376 static int __perf_event_stop(void *info)
2378 struct stop_event_data *sd = info;
2379 struct perf_event *event = sd->event;
2381 /* if it's already INACTIVE, do nothing */
2382 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2385 /* matches smp_wmb() in event_sched_in() */
2389 * There is a window with interrupts enabled before we get here,
2390 * so we need to check again lest we try to stop another CPU's event.
2392 if (READ_ONCE(event->oncpu) != smp_processor_id())
2395 event->pmu->stop(event, PERF_EF_UPDATE);
2398 * May race with the actual stop (through perf_pmu_output_stop()),
2399 * but it is only used for events with AUX ring buffer, and such
2400 * events will refuse to restart because of rb::aux_mmap_count==0,
2401 * see comments in perf_aux_output_begin().
2403 * Since this is happening on a event-local CPU, no trace is lost
2407 event->pmu->start(event, PERF_EF_START);
2412 static int perf_event_restart(struct perf_event *event)
2414 struct stop_event_data sd = {
2421 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2424 /* matches smp_wmb() in event_sched_in() */
2428 * We only want to restart ACTIVE events, so if the event goes
2429 * inactive here (event->oncpu==-1), there's nothing more to do;
2430 * fall through with ret==-ENXIO.
2432 ret = cpu_function_call(READ_ONCE(event->oncpu),
2433 __perf_event_stop, &sd);
2434 } while (ret == -EAGAIN);
2440 * In order to contain the amount of racy and tricky in the address filter
2441 * configuration management, it is a two part process:
2443 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2444 * we update the addresses of corresponding vmas in
2445 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2446 * (p2) when an event is scheduled in (pmu::add), it calls
2447 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2448 * if the generation has changed since the previous call.
2450 * If (p1) happens while the event is active, we restart it to force (p2).
2452 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2453 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2455 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2456 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2458 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2461 void perf_event_addr_filters_sync(struct perf_event *event)
2463 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2465 if (!has_addr_filter(event))
2468 raw_spin_lock(&ifh->lock);
2469 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2470 event->pmu->addr_filters_sync(event);
2471 event->hw.addr_filters_gen = event->addr_filters_gen;
2473 raw_spin_unlock(&ifh->lock);
2475 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2477 static int _perf_event_refresh(struct perf_event *event, int refresh)
2480 * not supported on inherited events
2482 if (event->attr.inherit || !is_sampling_event(event))
2485 atomic_add(refresh, &event->event_limit);
2486 _perf_event_enable(event);
2492 * See perf_event_disable()
2494 int perf_event_refresh(struct perf_event *event, int refresh)
2496 struct perf_event_context *ctx;
2499 ctx = perf_event_ctx_lock(event);
2500 ret = _perf_event_refresh(event, refresh);
2501 perf_event_ctx_unlock(event, ctx);
2505 EXPORT_SYMBOL_GPL(perf_event_refresh);
2507 static void ctx_sched_out(struct perf_event_context *ctx,
2508 struct perf_cpu_context *cpuctx,
2509 enum event_type_t event_type)
2511 int is_active = ctx->is_active;
2512 struct perf_event *event;
2514 lockdep_assert_held(&ctx->lock);
2516 if (likely(!ctx->nr_events)) {
2518 * See __perf_remove_from_context().
2520 WARN_ON_ONCE(ctx->is_active);
2522 WARN_ON_ONCE(cpuctx->task_ctx);
2526 ctx->is_active &= ~event_type;
2527 if (!(ctx->is_active & EVENT_ALL))
2531 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2532 if (!ctx->is_active)
2533 cpuctx->task_ctx = NULL;
2537 * Always update time if it was set; not only when it changes.
2538 * Otherwise we can 'forget' to update time for any but the last
2539 * context we sched out. For example:
2541 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2542 * ctx_sched_out(.event_type = EVENT_PINNED)
2544 * would only update time for the pinned events.
2546 if (is_active & EVENT_TIME) {
2547 /* update (and stop) ctx time */
2548 update_context_time(ctx);
2549 update_cgrp_time_from_cpuctx(cpuctx);
2552 is_active ^= ctx->is_active; /* changed bits */
2554 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2557 perf_pmu_disable(ctx->pmu);
2558 if (is_active & EVENT_PINNED) {
2559 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2560 group_sched_out(event, cpuctx, ctx);
2563 if (is_active & EVENT_FLEXIBLE) {
2564 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2565 group_sched_out(event, cpuctx, ctx);
2567 perf_pmu_enable(ctx->pmu);
2571 * Test whether two contexts are equivalent, i.e. whether they have both been
2572 * cloned from the same version of the same context.
2574 * Equivalence is measured using a generation number in the context that is
2575 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2576 * and list_del_event().
2578 static int context_equiv(struct perf_event_context *ctx1,
2579 struct perf_event_context *ctx2)
2581 lockdep_assert_held(&ctx1->lock);
2582 lockdep_assert_held(&ctx2->lock);
2584 /* Pinning disables the swap optimization */
2585 if (ctx1->pin_count || ctx2->pin_count)
2588 /* If ctx1 is the parent of ctx2 */
2589 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2592 /* If ctx2 is the parent of ctx1 */
2593 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2597 * If ctx1 and ctx2 have the same parent; we flatten the parent
2598 * hierarchy, see perf_event_init_context().
2600 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2601 ctx1->parent_gen == ctx2->parent_gen)
2608 static void __perf_event_sync_stat(struct perf_event *event,
2609 struct perf_event *next_event)
2613 if (!event->attr.inherit_stat)
2617 * Update the event value, we cannot use perf_event_read()
2618 * because we're in the middle of a context switch and have IRQs
2619 * disabled, which upsets smp_call_function_single(), however
2620 * we know the event must be on the current CPU, therefore we
2621 * don't need to use it.
2623 switch (event->state) {
2624 case PERF_EVENT_STATE_ACTIVE:
2625 event->pmu->read(event);
2628 case PERF_EVENT_STATE_INACTIVE:
2629 update_event_times(event);
2637 * In order to keep per-task stats reliable we need to flip the event
2638 * values when we flip the contexts.
2640 value = local64_read(&next_event->count);
2641 value = local64_xchg(&event->count, value);
2642 local64_set(&next_event->count, value);
2644 swap(event->total_time_enabled, next_event->total_time_enabled);
2645 swap(event->total_time_running, next_event->total_time_running);
2648 * Since we swizzled the values, update the user visible data too.
2650 perf_event_update_userpage(event);
2651 perf_event_update_userpage(next_event);
2654 static void perf_event_sync_stat(struct perf_event_context *ctx,
2655 struct perf_event_context *next_ctx)
2657 struct perf_event *event, *next_event;
2662 update_context_time(ctx);
2664 event = list_first_entry(&ctx->event_list,
2665 struct perf_event, event_entry);
2667 next_event = list_first_entry(&next_ctx->event_list,
2668 struct perf_event, event_entry);
2670 while (&event->event_entry != &ctx->event_list &&
2671 &next_event->event_entry != &next_ctx->event_list) {
2673 __perf_event_sync_stat(event, next_event);
2675 event = list_next_entry(event, event_entry);
2676 next_event = list_next_entry(next_event, event_entry);
2680 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2681 struct task_struct *next)
2683 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2684 struct perf_event_context *next_ctx;
2685 struct perf_event_context *parent, *next_parent;
2686 struct perf_cpu_context *cpuctx;
2692 cpuctx = __get_cpu_context(ctx);
2693 if (!cpuctx->task_ctx)
2697 next_ctx = next->perf_event_ctxp[ctxn];
2701 parent = rcu_dereference(ctx->parent_ctx);
2702 next_parent = rcu_dereference(next_ctx->parent_ctx);
2704 /* If neither context have a parent context; they cannot be clones. */
2705 if (!parent && !next_parent)
2708 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2710 * Looks like the two contexts are clones, so we might be
2711 * able to optimize the context switch. We lock both
2712 * contexts and check that they are clones under the
2713 * lock (including re-checking that neither has been
2714 * uncloned in the meantime). It doesn't matter which
2715 * order we take the locks because no other cpu could
2716 * be trying to lock both of these tasks.
2718 raw_spin_lock(&ctx->lock);
2719 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2720 if (context_equiv(ctx, next_ctx)) {
2721 WRITE_ONCE(ctx->task, next);
2722 WRITE_ONCE(next_ctx->task, task);
2724 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2727 * RCU_INIT_POINTER here is safe because we've not
2728 * modified the ctx and the above modification of
2729 * ctx->task and ctx->task_ctx_data are immaterial
2730 * since those values are always verified under
2731 * ctx->lock which we're now holding.
2733 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2734 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2738 perf_event_sync_stat(ctx, next_ctx);
2740 raw_spin_unlock(&next_ctx->lock);
2741 raw_spin_unlock(&ctx->lock);
2747 raw_spin_lock(&ctx->lock);
2748 task_ctx_sched_out(cpuctx, ctx);
2749 raw_spin_unlock(&ctx->lock);
2753 void perf_sched_cb_dec(struct pmu *pmu)
2755 this_cpu_dec(perf_sched_cb_usages);
2758 void perf_sched_cb_inc(struct pmu *pmu)
2760 this_cpu_inc(perf_sched_cb_usages);
2764 * This function provides the context switch callback to the lower code
2765 * layer. It is invoked ONLY when the context switch callback is enabled.
2767 static void perf_pmu_sched_task(struct task_struct *prev,
2768 struct task_struct *next,
2771 struct perf_cpu_context *cpuctx;
2773 unsigned long flags;
2778 local_irq_save(flags);
2782 list_for_each_entry_rcu(pmu, &pmus, entry) {
2783 if (pmu->sched_task) {
2784 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2786 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2788 perf_pmu_disable(pmu);
2790 pmu->sched_task(cpuctx->task_ctx, sched_in);
2792 perf_pmu_enable(pmu);
2794 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2800 local_irq_restore(flags);
2803 static void perf_event_switch(struct task_struct *task,
2804 struct task_struct *next_prev, bool sched_in);
2806 #define for_each_task_context_nr(ctxn) \
2807 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2810 * Called from scheduler to remove the events of the current task,
2811 * with interrupts disabled.
2813 * We stop each event and update the event value in event->count.
2815 * This does not protect us against NMI, but disable()
2816 * sets the disabled bit in the control field of event _before_
2817 * accessing the event control register. If a NMI hits, then it will
2818 * not restart the event.
2820 void __perf_event_task_sched_out(struct task_struct *task,
2821 struct task_struct *next)
2825 if (__this_cpu_read(perf_sched_cb_usages))
2826 perf_pmu_sched_task(task, next, false);
2828 if (atomic_read(&nr_switch_events))
2829 perf_event_switch(task, next, false);
2831 for_each_task_context_nr(ctxn)
2832 perf_event_context_sched_out(task, ctxn, next);
2835 * if cgroup events exist on this CPU, then we need
2836 * to check if we have to switch out PMU state.
2837 * cgroup event are system-wide mode only
2839 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2840 perf_cgroup_sched_out(task, next);
2844 * Called with IRQs disabled
2846 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2847 enum event_type_t event_type)
2849 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2853 ctx_pinned_sched_in(struct perf_event_context *ctx,
2854 struct perf_cpu_context *cpuctx)
2856 struct perf_event *event;
2858 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2859 if (event->state <= PERF_EVENT_STATE_OFF)
2861 if (!event_filter_match(event))
2864 /* may need to reset tstamp_enabled */
2865 if (is_cgroup_event(event))
2866 perf_cgroup_mark_enabled(event, ctx);
2868 if (group_can_go_on(event, cpuctx, 1))
2869 group_sched_in(event, cpuctx, ctx);
2872 * If this pinned group hasn't been scheduled,
2873 * put it in error state.
2875 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2876 update_group_times(event);
2877 event->state = PERF_EVENT_STATE_ERROR;
2883 ctx_flexible_sched_in(struct perf_event_context *ctx,
2884 struct perf_cpu_context *cpuctx)
2886 struct perf_event *event;
2889 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2890 /* Ignore events in OFF or ERROR state */
2891 if (event->state <= PERF_EVENT_STATE_OFF)
2894 * Listen to the 'cpu' scheduling filter constraint
2897 if (!event_filter_match(event))
2900 /* may need to reset tstamp_enabled */
2901 if (is_cgroup_event(event))
2902 perf_cgroup_mark_enabled(event, ctx);
2904 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2905 if (group_sched_in(event, cpuctx, ctx))
2912 ctx_sched_in(struct perf_event_context *ctx,
2913 struct perf_cpu_context *cpuctx,
2914 enum event_type_t event_type,
2915 struct task_struct *task)
2917 int is_active = ctx->is_active;
2920 lockdep_assert_held(&ctx->lock);
2922 if (likely(!ctx->nr_events))
2925 ctx->is_active |= (event_type | EVENT_TIME);
2928 cpuctx->task_ctx = ctx;
2930 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2933 is_active ^= ctx->is_active; /* changed bits */
2935 if (is_active & EVENT_TIME) {
2936 /* start ctx time */
2938 ctx->timestamp = now;
2939 perf_cgroup_set_timestamp(task, ctx);
2943 * First go through the list and put on any pinned groups
2944 * in order to give them the best chance of going on.
2946 if (is_active & EVENT_PINNED)
2947 ctx_pinned_sched_in(ctx, cpuctx);
2949 /* Then walk through the lower prio flexible groups */
2950 if (is_active & EVENT_FLEXIBLE)
2951 ctx_flexible_sched_in(ctx, cpuctx);
2954 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2955 enum event_type_t event_type,
2956 struct task_struct *task)
2958 struct perf_event_context *ctx = &cpuctx->ctx;
2960 ctx_sched_in(ctx, cpuctx, event_type, task);
2963 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2964 struct task_struct *task)
2966 struct perf_cpu_context *cpuctx;
2968 cpuctx = __get_cpu_context(ctx);
2969 if (cpuctx->task_ctx == ctx)
2972 perf_ctx_lock(cpuctx, ctx);
2973 perf_pmu_disable(ctx->pmu);
2975 * We want to keep the following priority order:
2976 * cpu pinned (that don't need to move), task pinned,
2977 * cpu flexible, task flexible.
2979 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2980 perf_event_sched_in(cpuctx, ctx, task);
2981 perf_pmu_enable(ctx->pmu);
2982 perf_ctx_unlock(cpuctx, ctx);
2986 * Called from scheduler to add the events of the current task
2987 * with interrupts disabled.
2989 * We restore the event value and then enable it.
2991 * This does not protect us against NMI, but enable()
2992 * sets the enabled bit in the control field of event _before_
2993 * accessing the event control register. If a NMI hits, then it will
2994 * keep the event running.
2996 void __perf_event_task_sched_in(struct task_struct *prev,
2997 struct task_struct *task)
2999 struct perf_event_context *ctx;
3003 * If cgroup events exist on this CPU, then we need to check if we have
3004 * to switch in PMU state; cgroup event are system-wide mode only.
3006 * Since cgroup events are CPU events, we must schedule these in before
3007 * we schedule in the task events.
3009 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3010 perf_cgroup_sched_in(prev, task);
3012 for_each_task_context_nr(ctxn) {
3013 ctx = task->perf_event_ctxp[ctxn];
3017 perf_event_context_sched_in(ctx, task);
3020 if (atomic_read(&nr_switch_events))
3021 perf_event_switch(task, prev, true);
3023 if (__this_cpu_read(perf_sched_cb_usages))
3024 perf_pmu_sched_task(prev, task, true);
3027 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3029 u64 frequency = event->attr.sample_freq;
3030 u64 sec = NSEC_PER_SEC;
3031 u64 divisor, dividend;
3033 int count_fls, nsec_fls, frequency_fls, sec_fls;
3035 count_fls = fls64(count);
3036 nsec_fls = fls64(nsec);
3037 frequency_fls = fls64(frequency);
3041 * We got @count in @nsec, with a target of sample_freq HZ
3042 * the target period becomes:
3045 * period = -------------------
3046 * @nsec * sample_freq
3051 * Reduce accuracy by one bit such that @a and @b converge
3052 * to a similar magnitude.
3054 #define REDUCE_FLS(a, b) \
3056 if (a##_fls > b##_fls) { \
3066 * Reduce accuracy until either term fits in a u64, then proceed with
3067 * the other, so that finally we can do a u64/u64 division.
3069 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3070 REDUCE_FLS(nsec, frequency);
3071 REDUCE_FLS(sec, count);
3074 if (count_fls + sec_fls > 64) {
3075 divisor = nsec * frequency;
3077 while (count_fls + sec_fls > 64) {
3078 REDUCE_FLS(count, sec);
3082 dividend = count * sec;
3084 dividend = count * sec;
3086 while (nsec_fls + frequency_fls > 64) {
3087 REDUCE_FLS(nsec, frequency);
3091 divisor = nsec * frequency;
3097 return div64_u64(dividend, divisor);
3100 static DEFINE_PER_CPU(int, perf_throttled_count);
3101 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3103 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3105 struct hw_perf_event *hwc = &event->hw;
3106 s64 period, sample_period;
3109 period = perf_calculate_period(event, nsec, count);
3111 delta = (s64)(period - hwc->sample_period);
3112 delta = (delta + 7) / 8; /* low pass filter */
3114 sample_period = hwc->sample_period + delta;
3119 hwc->sample_period = sample_period;
3121 if (local64_read(&hwc->period_left) > 8*sample_period) {
3123 event->pmu->stop(event, PERF_EF_UPDATE);
3125 local64_set(&hwc->period_left, 0);
3128 event->pmu->start(event, PERF_EF_RELOAD);
3133 * combine freq adjustment with unthrottling to avoid two passes over the
3134 * events. At the same time, make sure, having freq events does not change
3135 * the rate of unthrottling as that would introduce bias.
3137 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3140 struct perf_event *event;
3141 struct hw_perf_event *hwc;
3142 u64 now, period = TICK_NSEC;
3146 * only need to iterate over all events iff:
3147 * - context have events in frequency mode (needs freq adjust)
3148 * - there are events to unthrottle on this cpu
3150 if (!(ctx->nr_freq || needs_unthr))
3153 raw_spin_lock(&ctx->lock);
3154 perf_pmu_disable(ctx->pmu);
3156 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3157 if (event->state != PERF_EVENT_STATE_ACTIVE)
3160 if (!event_filter_match(event))
3163 perf_pmu_disable(event->pmu);
3167 if (hwc->interrupts == MAX_INTERRUPTS) {
3168 hwc->interrupts = 0;
3169 perf_log_throttle(event, 1);
3170 event->pmu->start(event, 0);
3173 if (!event->attr.freq || !event->attr.sample_freq)
3177 * stop the event and update event->count
3179 event->pmu->stop(event, PERF_EF_UPDATE);
3181 now = local64_read(&event->count);
3182 delta = now - hwc->freq_count_stamp;
3183 hwc->freq_count_stamp = now;
3187 * reload only if value has changed
3188 * we have stopped the event so tell that
3189 * to perf_adjust_period() to avoid stopping it
3193 perf_adjust_period(event, period, delta, false);
3195 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3197 perf_pmu_enable(event->pmu);
3200 perf_pmu_enable(ctx->pmu);
3201 raw_spin_unlock(&ctx->lock);
3205 * Round-robin a context's events:
3207 static void rotate_ctx(struct perf_event_context *ctx)
3210 * Rotate the first entry last of non-pinned groups. Rotation might be
3211 * disabled by the inheritance code.
3213 if (!ctx->rotate_disable)
3214 list_rotate_left(&ctx->flexible_groups);
3217 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3219 struct perf_event_context *ctx = NULL;
3222 if (cpuctx->ctx.nr_events) {
3223 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3227 ctx = cpuctx->task_ctx;
3228 if (ctx && ctx->nr_events) {
3229 if (ctx->nr_events != ctx->nr_active)
3236 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3237 perf_pmu_disable(cpuctx->ctx.pmu);
3239 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3241 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3243 rotate_ctx(&cpuctx->ctx);
3247 perf_event_sched_in(cpuctx, ctx, current);
3249 perf_pmu_enable(cpuctx->ctx.pmu);
3250 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3256 void perf_event_task_tick(void)
3258 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3259 struct perf_event_context *ctx, *tmp;
3262 WARN_ON(!irqs_disabled());
3264 __this_cpu_inc(perf_throttled_seq);
3265 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3266 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3268 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3269 perf_adjust_freq_unthr_context(ctx, throttled);
3272 static int event_enable_on_exec(struct perf_event *event,
3273 struct perf_event_context *ctx)
3275 if (!event->attr.enable_on_exec)
3278 event->attr.enable_on_exec = 0;
3279 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3282 __perf_event_mark_enabled(event);
3288 * Enable all of a task's events that have been marked enable-on-exec.
3289 * This expects task == current.
3291 static void perf_event_enable_on_exec(int ctxn)
3293 struct perf_event_context *ctx, *clone_ctx = NULL;
3294 struct perf_cpu_context *cpuctx;
3295 struct perf_event *event;
3296 unsigned long flags;
3299 local_irq_save(flags);
3300 ctx = current->perf_event_ctxp[ctxn];
3301 if (!ctx || !ctx->nr_events)
3304 cpuctx = __get_cpu_context(ctx);
3305 perf_ctx_lock(cpuctx, ctx);
3306 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3307 list_for_each_entry(event, &ctx->event_list, event_entry)
3308 enabled |= event_enable_on_exec(event, ctx);
3311 * Unclone and reschedule this context if we enabled any event.
3314 clone_ctx = unclone_ctx(ctx);
3315 ctx_resched(cpuctx, ctx);
3317 perf_ctx_unlock(cpuctx, ctx);
3320 local_irq_restore(flags);
3326 struct perf_read_data {
3327 struct perf_event *event;
3333 * Cross CPU call to read the hardware event
3335 static void __perf_event_read(void *info)
3337 struct perf_read_data *data = info;
3338 struct perf_event *sub, *event = data->event;
3339 struct perf_event_context *ctx = event->ctx;
3340 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3341 struct pmu *pmu = event->pmu;
3344 * If this is a task context, we need to check whether it is
3345 * the current task context of this cpu. If not it has been
3346 * scheduled out before the smp call arrived. In that case
3347 * event->count would have been updated to a recent sample
3348 * when the event was scheduled out.
3350 if (ctx->task && cpuctx->task_ctx != ctx)
3353 raw_spin_lock(&ctx->lock);
3354 if (ctx->is_active) {
3355 update_context_time(ctx);
3356 update_cgrp_time_from_event(event);
3359 update_event_times(event);
3360 if (event->state != PERF_EVENT_STATE_ACTIVE)
3369 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3373 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3374 update_event_times(sub);
3375 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3377 * Use sibling's PMU rather than @event's since
3378 * sibling could be on different (eg: software) PMU.
3380 sub->pmu->read(sub);
3384 data->ret = pmu->commit_txn(pmu);
3387 raw_spin_unlock(&ctx->lock);
3390 static inline u64 perf_event_count(struct perf_event *event)
3392 if (event->pmu->count)
3393 return event->pmu->count(event);
3395 return __perf_event_count(event);
3399 * NMI-safe method to read a local event, that is an event that
3401 * - either for the current task, or for this CPU
3402 * - does not have inherit set, for inherited task events
3403 * will not be local and we cannot read them atomically
3404 * - must not have a pmu::count method
3406 u64 perf_event_read_local(struct perf_event *event)
3408 unsigned long flags;
3412 * Disabling interrupts avoids all counter scheduling (context
3413 * switches, timer based rotation and IPIs).
3415 local_irq_save(flags);
3417 /* If this is a per-task event, it must be for current */
3418 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3419 event->hw.target != current);
3421 /* If this is a per-CPU event, it must be for this CPU */
3422 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3423 event->cpu != smp_processor_id());
3426 * It must not be an event with inherit set, we cannot read
3427 * all child counters from atomic context.
3429 WARN_ON_ONCE(event->attr.inherit);
3432 * It must not have a pmu::count method, those are not
3435 WARN_ON_ONCE(event->pmu->count);
3438 * If the event is currently on this CPU, its either a per-task event,
3439 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3442 if (event->oncpu == smp_processor_id())
3443 event->pmu->read(event);
3445 val = local64_read(&event->count);
3446 local_irq_restore(flags);
3451 static int perf_event_read(struct perf_event *event, bool group)
3456 * If event is enabled and currently active on a CPU, update the
3457 * value in the event structure:
3459 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3460 struct perf_read_data data = {
3465 smp_call_function_single(event->oncpu,
3466 __perf_event_read, &data, 1);
3468 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3469 struct perf_event_context *ctx = event->ctx;
3470 unsigned long flags;
3472 raw_spin_lock_irqsave(&ctx->lock, flags);
3474 * may read while context is not active
3475 * (e.g., thread is blocked), in that case
3476 * we cannot update context time
3478 if (ctx->is_active) {
3479 update_context_time(ctx);
3480 update_cgrp_time_from_event(event);
3483 update_group_times(event);
3485 update_event_times(event);
3486 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3493 * Initialize the perf_event context in a task_struct:
3495 static void __perf_event_init_context(struct perf_event_context *ctx)
3497 raw_spin_lock_init(&ctx->lock);
3498 mutex_init(&ctx->mutex);
3499 INIT_LIST_HEAD(&ctx->active_ctx_list);
3500 INIT_LIST_HEAD(&ctx->pinned_groups);
3501 INIT_LIST_HEAD(&ctx->flexible_groups);
3502 INIT_LIST_HEAD(&ctx->event_list);
3503 atomic_set(&ctx->refcount, 1);
3506 static struct perf_event_context *
3507 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3509 struct perf_event_context *ctx;
3511 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3515 __perf_event_init_context(ctx);
3518 get_task_struct(task);
3525 static struct task_struct *
3526 find_lively_task_by_vpid(pid_t vpid)
3528 struct task_struct *task;
3534 task = find_task_by_vpid(vpid);
3536 get_task_struct(task);
3540 return ERR_PTR(-ESRCH);
3546 * Returns a matching context with refcount and pincount.
3548 static struct perf_event_context *
3549 find_get_context(struct pmu *pmu, struct task_struct *task,
3550 struct perf_event *event)
3552 struct perf_event_context *ctx, *clone_ctx = NULL;
3553 struct perf_cpu_context *cpuctx;
3554 void *task_ctx_data = NULL;
3555 unsigned long flags;
3557 int cpu = event->cpu;
3560 /* Must be root to operate on a CPU event: */
3561 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3562 return ERR_PTR(-EACCES);
3565 * We could be clever and allow to attach a event to an
3566 * offline CPU and activate it when the CPU comes up, but
3569 if (!cpu_online(cpu))
3570 return ERR_PTR(-ENODEV);
3572 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3581 ctxn = pmu->task_ctx_nr;
3585 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3586 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3587 if (!task_ctx_data) {
3594 ctx = perf_lock_task_context(task, ctxn, &flags);
3596 clone_ctx = unclone_ctx(ctx);
3599 if (task_ctx_data && !ctx->task_ctx_data) {
3600 ctx->task_ctx_data = task_ctx_data;
3601 task_ctx_data = NULL;
3603 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3608 ctx = alloc_perf_context(pmu, task);
3613 if (task_ctx_data) {
3614 ctx->task_ctx_data = task_ctx_data;
3615 task_ctx_data = NULL;
3619 mutex_lock(&task->perf_event_mutex);
3621 * If it has already passed perf_event_exit_task().
3622 * we must see PF_EXITING, it takes this mutex too.
3624 if (task->flags & PF_EXITING)
3626 else if (task->perf_event_ctxp[ctxn])
3631 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3633 mutex_unlock(&task->perf_event_mutex);
3635 if (unlikely(err)) {
3644 kfree(task_ctx_data);
3648 kfree(task_ctx_data);
3649 return ERR_PTR(err);
3652 static void perf_event_free_filter(struct perf_event *event);
3653 static void perf_event_free_bpf_prog(struct perf_event *event);
3655 static void free_event_rcu(struct rcu_head *head)
3657 struct perf_event *event;
3659 event = container_of(head, struct perf_event, rcu_head);
3661 put_pid_ns(event->ns);
3662 perf_event_free_filter(event);
3666 static void ring_buffer_attach(struct perf_event *event,
3667 struct ring_buffer *rb);
3669 static void detach_sb_event(struct perf_event *event)
3671 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3673 raw_spin_lock(&pel->lock);
3674 list_del_rcu(&event->sb_list);
3675 raw_spin_unlock(&pel->lock);
3678 static void unaccount_pmu_sb_event(struct perf_event *event)
3683 if (event->attach_state & PERF_ATTACH_TASK)
3686 detach_sb_event(event);
3689 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3694 if (is_cgroup_event(event))
3695 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3698 #ifdef CONFIG_NO_HZ_FULL
3699 static DEFINE_SPINLOCK(nr_freq_lock);
3702 static void unaccount_freq_event_nohz(void)
3704 #ifdef CONFIG_NO_HZ_FULL
3705 spin_lock(&nr_freq_lock);
3706 if (atomic_dec_and_test(&nr_freq_events))
3707 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3708 spin_unlock(&nr_freq_lock);
3712 static void unaccount_freq_event(void)
3714 if (tick_nohz_full_enabled())
3715 unaccount_freq_event_nohz();
3717 atomic_dec(&nr_freq_events);
3720 static void unaccount_event(struct perf_event *event)
3727 if (event->attach_state & PERF_ATTACH_TASK)
3729 if (event->attr.mmap || event->attr.mmap_data)
3730 atomic_dec(&nr_mmap_events);
3731 if (event->attr.comm)
3732 atomic_dec(&nr_comm_events);
3733 if (event->attr.task)
3734 atomic_dec(&nr_task_events);
3735 if (event->attr.freq)
3736 unaccount_freq_event();
3737 if (event->attr.context_switch) {
3739 atomic_dec(&nr_switch_events);
3741 if (is_cgroup_event(event))
3743 if (has_branch_stack(event))
3747 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3748 schedule_delayed_work(&perf_sched_work, HZ);
3751 unaccount_event_cpu(event, event->cpu);
3753 unaccount_pmu_sb_event(event);
3756 static void perf_sched_delayed(struct work_struct *work)
3758 mutex_lock(&perf_sched_mutex);
3759 if (atomic_dec_and_test(&perf_sched_count))
3760 static_branch_disable(&perf_sched_events);
3761 mutex_unlock(&perf_sched_mutex);
3765 * The following implement mutual exclusion of events on "exclusive" pmus
3766 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3767 * at a time, so we disallow creating events that might conflict, namely:
3769 * 1) cpu-wide events in the presence of per-task events,
3770 * 2) per-task events in the presence of cpu-wide events,
3771 * 3) two matching events on the same context.
3773 * The former two cases are handled in the allocation path (perf_event_alloc(),
3774 * _free_event()), the latter -- before the first perf_install_in_context().
3776 static int exclusive_event_init(struct perf_event *event)
3778 struct pmu *pmu = event->pmu;
3780 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3784 * Prevent co-existence of per-task and cpu-wide events on the
3785 * same exclusive pmu.
3787 * Negative pmu::exclusive_cnt means there are cpu-wide
3788 * events on this "exclusive" pmu, positive means there are
3791 * Since this is called in perf_event_alloc() path, event::ctx
3792 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3793 * to mean "per-task event", because unlike other attach states it
3794 * never gets cleared.
3796 if (event->attach_state & PERF_ATTACH_TASK) {
3797 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3800 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3807 static void exclusive_event_destroy(struct perf_event *event)
3809 struct pmu *pmu = event->pmu;
3811 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3814 /* see comment in exclusive_event_init() */
3815 if (event->attach_state & PERF_ATTACH_TASK)
3816 atomic_dec(&pmu->exclusive_cnt);
3818 atomic_inc(&pmu->exclusive_cnt);
3821 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3823 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3824 (e1->cpu == e2->cpu ||
3831 /* Called under the same ctx::mutex as perf_install_in_context() */
3832 static bool exclusive_event_installable(struct perf_event *event,
3833 struct perf_event_context *ctx)
3835 struct perf_event *iter_event;
3836 struct pmu *pmu = event->pmu;
3838 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3841 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3842 if (exclusive_event_match(iter_event, event))
3849 static void perf_addr_filters_splice(struct perf_event *event,
3850 struct list_head *head);
3852 static void _free_event(struct perf_event *event)
3854 irq_work_sync(&event->pending);
3856 unaccount_event(event);
3860 * Can happen when we close an event with re-directed output.
3862 * Since we have a 0 refcount, perf_mmap_close() will skip
3863 * over us; possibly making our ring_buffer_put() the last.
3865 mutex_lock(&event->mmap_mutex);
3866 ring_buffer_attach(event, NULL);
3867 mutex_unlock(&event->mmap_mutex);
3870 if (is_cgroup_event(event))
3871 perf_detach_cgroup(event);
3873 if (!event->parent) {
3874 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3875 put_callchain_buffers();
3878 perf_event_free_bpf_prog(event);
3879 perf_addr_filters_splice(event, NULL);
3880 kfree(event->addr_filters_offs);
3883 event->destroy(event);
3886 put_ctx(event->ctx);
3889 exclusive_event_destroy(event);
3890 module_put(event->pmu->module);
3893 call_rcu(&event->rcu_head, free_event_rcu);
3897 * Used to free events which have a known refcount of 1, such as in error paths
3898 * where the event isn't exposed yet and inherited events.
3900 static void free_event(struct perf_event *event)
3902 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3903 "unexpected event refcount: %ld; ptr=%p\n",
3904 atomic_long_read(&event->refcount), event)) {
3905 /* leak to avoid use-after-free */
3913 * Remove user event from the owner task.
3915 static void perf_remove_from_owner(struct perf_event *event)
3917 struct task_struct *owner;
3921 * Matches the smp_store_release() in perf_event_exit_task(). If we
3922 * observe !owner it means the list deletion is complete and we can
3923 * indeed free this event, otherwise we need to serialize on
3924 * owner->perf_event_mutex.
3926 owner = lockless_dereference(event->owner);
3929 * Since delayed_put_task_struct() also drops the last
3930 * task reference we can safely take a new reference
3931 * while holding the rcu_read_lock().
3933 get_task_struct(owner);
3939 * If we're here through perf_event_exit_task() we're already
3940 * holding ctx->mutex which would be an inversion wrt. the
3941 * normal lock order.
3943 * However we can safely take this lock because its the child
3946 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3949 * We have to re-check the event->owner field, if it is cleared
3950 * we raced with perf_event_exit_task(), acquiring the mutex
3951 * ensured they're done, and we can proceed with freeing the
3955 list_del_init(&event->owner_entry);
3956 smp_store_release(&event->owner, NULL);
3958 mutex_unlock(&owner->perf_event_mutex);
3959 put_task_struct(owner);
3963 static void put_event(struct perf_event *event)
3965 if (!atomic_long_dec_and_test(&event->refcount))
3972 * Kill an event dead; while event:refcount will preserve the event
3973 * object, it will not preserve its functionality. Once the last 'user'
3974 * gives up the object, we'll destroy the thing.
3976 int perf_event_release_kernel(struct perf_event *event)
3978 struct perf_event_context *ctx = event->ctx;
3979 struct perf_event *child, *tmp;
3982 * If we got here through err_file: fput(event_file); we will not have
3983 * attached to a context yet.
3986 WARN_ON_ONCE(event->attach_state &
3987 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3991 if (!is_kernel_event(event))
3992 perf_remove_from_owner(event);
3994 ctx = perf_event_ctx_lock(event);
3995 WARN_ON_ONCE(ctx->parent_ctx);
3996 perf_remove_from_context(event, DETACH_GROUP);
3998 raw_spin_lock_irq(&ctx->lock);
4000 * Mark this even as STATE_DEAD, there is no external reference to it
4003 * Anybody acquiring event->child_mutex after the below loop _must_
4004 * also see this, most importantly inherit_event() which will avoid
4005 * placing more children on the list.
4007 * Thus this guarantees that we will in fact observe and kill _ALL_
4010 event->state = PERF_EVENT_STATE_DEAD;
4011 raw_spin_unlock_irq(&ctx->lock);
4013 perf_event_ctx_unlock(event, ctx);
4016 mutex_lock(&event->child_mutex);
4017 list_for_each_entry(child, &event->child_list, child_list) {
4020 * Cannot change, child events are not migrated, see the
4021 * comment with perf_event_ctx_lock_nested().
4023 ctx = lockless_dereference(child->ctx);
4025 * Since child_mutex nests inside ctx::mutex, we must jump
4026 * through hoops. We start by grabbing a reference on the ctx.
4028 * Since the event cannot get freed while we hold the
4029 * child_mutex, the context must also exist and have a !0
4035 * Now that we have a ctx ref, we can drop child_mutex, and
4036 * acquire ctx::mutex without fear of it going away. Then we
4037 * can re-acquire child_mutex.
4039 mutex_unlock(&event->child_mutex);
4040 mutex_lock(&ctx->mutex);
4041 mutex_lock(&event->child_mutex);
4044 * Now that we hold ctx::mutex and child_mutex, revalidate our
4045 * state, if child is still the first entry, it didn't get freed
4046 * and we can continue doing so.
4048 tmp = list_first_entry_or_null(&event->child_list,
4049 struct perf_event, child_list);
4051 perf_remove_from_context(child, DETACH_GROUP);
4052 list_del(&child->child_list);
4055 * This matches the refcount bump in inherit_event();
4056 * this can't be the last reference.
4061 mutex_unlock(&event->child_mutex);
4062 mutex_unlock(&ctx->mutex);
4066 mutex_unlock(&event->child_mutex);
4069 put_event(event); /* Must be the 'last' reference */
4072 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4075 * Called when the last reference to the file is gone.
4077 static int perf_release(struct inode *inode, struct file *file)
4079 perf_event_release_kernel(file->private_data);
4083 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4085 struct perf_event *child;
4091 mutex_lock(&event->child_mutex);
4093 (void)perf_event_read(event, false);
4094 total += perf_event_count(event);
4096 *enabled += event->total_time_enabled +
4097 atomic64_read(&event->child_total_time_enabled);
4098 *running += event->total_time_running +
4099 atomic64_read(&event->child_total_time_running);
4101 list_for_each_entry(child, &event->child_list, child_list) {
4102 (void)perf_event_read(child, false);
4103 total += perf_event_count(child);
4104 *enabled += child->total_time_enabled;
4105 *running += child->total_time_running;
4107 mutex_unlock(&event->child_mutex);
4111 EXPORT_SYMBOL_GPL(perf_event_read_value);
4113 static int __perf_read_group_add(struct perf_event *leader,
4114 u64 read_format, u64 *values)
4116 struct perf_event *sub;
4117 int n = 1; /* skip @nr */
4120 ret = perf_event_read(leader, true);
4125 * Since we co-schedule groups, {enabled,running} times of siblings
4126 * will be identical to those of the leader, so we only publish one
4129 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4130 values[n++] += leader->total_time_enabled +
4131 atomic64_read(&leader->child_total_time_enabled);
4134 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4135 values[n++] += leader->total_time_running +
4136 atomic64_read(&leader->child_total_time_running);
4140 * Write {count,id} tuples for every sibling.
4142 values[n++] += perf_event_count(leader);
4143 if (read_format & PERF_FORMAT_ID)
4144 values[n++] = primary_event_id(leader);
4146 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4147 values[n++] += perf_event_count(sub);
4148 if (read_format & PERF_FORMAT_ID)
4149 values[n++] = primary_event_id(sub);
4155 static int perf_read_group(struct perf_event *event,
4156 u64 read_format, char __user *buf)
4158 struct perf_event *leader = event->group_leader, *child;
4159 struct perf_event_context *ctx = leader->ctx;
4163 lockdep_assert_held(&ctx->mutex);
4165 values = kzalloc(event->read_size, GFP_KERNEL);
4169 values[0] = 1 + leader->nr_siblings;
4172 * By locking the child_mutex of the leader we effectively
4173 * lock the child list of all siblings.. XXX explain how.
4175 mutex_lock(&leader->child_mutex);
4177 ret = __perf_read_group_add(leader, read_format, values);
4181 list_for_each_entry(child, &leader->child_list, child_list) {
4182 ret = __perf_read_group_add(child, read_format, values);
4187 mutex_unlock(&leader->child_mutex);
4189 ret = event->read_size;
4190 if (copy_to_user(buf, values, event->read_size))
4195 mutex_unlock(&leader->child_mutex);
4201 static int perf_read_one(struct perf_event *event,
4202 u64 read_format, char __user *buf)
4204 u64 enabled, running;
4208 values[n++] = perf_event_read_value(event, &enabled, &running);
4209 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4210 values[n++] = enabled;
4211 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4212 values[n++] = running;
4213 if (read_format & PERF_FORMAT_ID)
4214 values[n++] = primary_event_id(event);
4216 if (copy_to_user(buf, values, n * sizeof(u64)))
4219 return n * sizeof(u64);
4222 static bool is_event_hup(struct perf_event *event)
4226 if (event->state > PERF_EVENT_STATE_EXIT)
4229 mutex_lock(&event->child_mutex);
4230 no_children = list_empty(&event->child_list);
4231 mutex_unlock(&event->child_mutex);
4236 * Read the performance event - simple non blocking version for now
4239 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4241 u64 read_format = event->attr.read_format;
4245 * Return end-of-file for a read on a event that is in
4246 * error state (i.e. because it was pinned but it couldn't be
4247 * scheduled on to the CPU at some point).
4249 if (event->state == PERF_EVENT_STATE_ERROR)
4252 if (count < event->read_size)
4255 WARN_ON_ONCE(event->ctx->parent_ctx);
4256 if (read_format & PERF_FORMAT_GROUP)
4257 ret = perf_read_group(event, read_format, buf);
4259 ret = perf_read_one(event, read_format, buf);
4265 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4267 struct perf_event *event = file->private_data;
4268 struct perf_event_context *ctx;
4271 ctx = perf_event_ctx_lock(event);
4272 ret = __perf_read(event, buf, count);
4273 perf_event_ctx_unlock(event, ctx);
4278 static unsigned int perf_poll(struct file *file, poll_table *wait)
4280 struct perf_event *event = file->private_data;
4281 struct ring_buffer *rb;
4282 unsigned int events = POLLHUP;
4284 poll_wait(file, &event->waitq, wait);
4286 if (is_event_hup(event))
4290 * Pin the event->rb by taking event->mmap_mutex; otherwise
4291 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4293 mutex_lock(&event->mmap_mutex);
4296 events = atomic_xchg(&rb->poll, 0);
4297 mutex_unlock(&event->mmap_mutex);
4301 static void _perf_event_reset(struct perf_event *event)
4303 (void)perf_event_read(event, false);
4304 local64_set(&event->count, 0);
4305 perf_event_update_userpage(event);
4309 * Holding the top-level event's child_mutex means that any
4310 * descendant process that has inherited this event will block
4311 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4312 * task existence requirements of perf_event_enable/disable.
4314 static void perf_event_for_each_child(struct perf_event *event,
4315 void (*func)(struct perf_event *))
4317 struct perf_event *child;
4319 WARN_ON_ONCE(event->ctx->parent_ctx);
4321 mutex_lock(&event->child_mutex);
4323 list_for_each_entry(child, &event->child_list, child_list)
4325 mutex_unlock(&event->child_mutex);
4328 static void perf_event_for_each(struct perf_event *event,
4329 void (*func)(struct perf_event *))
4331 struct perf_event_context *ctx = event->ctx;
4332 struct perf_event *sibling;
4334 lockdep_assert_held(&ctx->mutex);
4336 event = event->group_leader;
4338 perf_event_for_each_child(event, func);
4339 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4340 perf_event_for_each_child(sibling, func);
4343 static void __perf_event_period(struct perf_event *event,
4344 struct perf_cpu_context *cpuctx,
4345 struct perf_event_context *ctx,
4348 u64 value = *((u64 *)info);
4351 if (event->attr.freq) {
4352 event->attr.sample_freq = value;
4354 event->attr.sample_period = value;
4355 event->hw.sample_period = value;
4358 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4360 perf_pmu_disable(ctx->pmu);
4362 * We could be throttled; unthrottle now to avoid the tick
4363 * trying to unthrottle while we already re-started the event.
4365 if (event->hw.interrupts == MAX_INTERRUPTS) {
4366 event->hw.interrupts = 0;
4367 perf_log_throttle(event, 1);
4369 event->pmu->stop(event, PERF_EF_UPDATE);
4372 local64_set(&event->hw.period_left, 0);
4375 event->pmu->start(event, PERF_EF_RELOAD);
4376 perf_pmu_enable(ctx->pmu);
4380 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4384 if (!is_sampling_event(event))
4387 if (copy_from_user(&value, arg, sizeof(value)))
4393 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4396 event_function_call(event, __perf_event_period, &value);
4401 static const struct file_operations perf_fops;
4403 static inline int perf_fget_light(int fd, struct fd *p)
4405 struct fd f = fdget(fd);
4409 if (f.file->f_op != &perf_fops) {
4417 static int perf_event_set_output(struct perf_event *event,
4418 struct perf_event *output_event);
4419 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4420 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4422 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4424 void (*func)(struct perf_event *);
4428 case PERF_EVENT_IOC_ENABLE:
4429 func = _perf_event_enable;
4431 case PERF_EVENT_IOC_DISABLE:
4432 func = _perf_event_disable;
4434 case PERF_EVENT_IOC_RESET:
4435 func = _perf_event_reset;
4438 case PERF_EVENT_IOC_REFRESH:
4439 return _perf_event_refresh(event, arg);
4441 case PERF_EVENT_IOC_PERIOD:
4442 return perf_event_period(event, (u64 __user *)arg);
4444 case PERF_EVENT_IOC_ID:
4446 u64 id = primary_event_id(event);
4448 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4453 case PERF_EVENT_IOC_SET_OUTPUT:
4457 struct perf_event *output_event;
4459 ret = perf_fget_light(arg, &output);
4462 output_event = output.file->private_data;
4463 ret = perf_event_set_output(event, output_event);
4466 ret = perf_event_set_output(event, NULL);
4471 case PERF_EVENT_IOC_SET_FILTER:
4472 return perf_event_set_filter(event, (void __user *)arg);
4474 case PERF_EVENT_IOC_SET_BPF:
4475 return perf_event_set_bpf_prog(event, arg);
4477 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4478 struct ring_buffer *rb;
4481 rb = rcu_dereference(event->rb);
4482 if (!rb || !rb->nr_pages) {
4486 rb_toggle_paused(rb, !!arg);
4494 if (flags & PERF_IOC_FLAG_GROUP)
4495 perf_event_for_each(event, func);
4497 perf_event_for_each_child(event, func);
4502 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4504 struct perf_event *event = file->private_data;
4505 struct perf_event_context *ctx;
4508 ctx = perf_event_ctx_lock(event);
4509 ret = _perf_ioctl(event, cmd, arg);
4510 perf_event_ctx_unlock(event, ctx);
4515 #ifdef CONFIG_COMPAT
4516 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4519 switch (_IOC_NR(cmd)) {
4520 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4521 case _IOC_NR(PERF_EVENT_IOC_ID):
4522 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4523 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4524 cmd &= ~IOCSIZE_MASK;
4525 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4529 return perf_ioctl(file, cmd, arg);
4532 # define perf_compat_ioctl NULL
4535 int perf_event_task_enable(void)
4537 struct perf_event_context *ctx;
4538 struct perf_event *event;
4540 mutex_lock(¤t->perf_event_mutex);
4541 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4542 ctx = perf_event_ctx_lock(event);
4543 perf_event_for_each_child(event, _perf_event_enable);
4544 perf_event_ctx_unlock(event, ctx);
4546 mutex_unlock(¤t->perf_event_mutex);
4551 int perf_event_task_disable(void)
4553 struct perf_event_context *ctx;
4554 struct perf_event *event;
4556 mutex_lock(¤t->perf_event_mutex);
4557 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4558 ctx = perf_event_ctx_lock(event);
4559 perf_event_for_each_child(event, _perf_event_disable);
4560 perf_event_ctx_unlock(event, ctx);
4562 mutex_unlock(¤t->perf_event_mutex);
4567 static int perf_event_index(struct perf_event *event)
4569 if (event->hw.state & PERF_HES_STOPPED)
4572 if (event->state != PERF_EVENT_STATE_ACTIVE)
4575 return event->pmu->event_idx(event);
4578 static void calc_timer_values(struct perf_event *event,
4585 *now = perf_clock();
4586 ctx_time = event->shadow_ctx_time + *now;
4587 *enabled = ctx_time - event->tstamp_enabled;
4588 *running = ctx_time - event->tstamp_running;
4591 static void perf_event_init_userpage(struct perf_event *event)
4593 struct perf_event_mmap_page *userpg;
4594 struct ring_buffer *rb;
4597 rb = rcu_dereference(event->rb);
4601 userpg = rb->user_page;
4603 /* Allow new userspace to detect that bit 0 is deprecated */
4604 userpg->cap_bit0_is_deprecated = 1;
4605 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4606 userpg->data_offset = PAGE_SIZE;
4607 userpg->data_size = perf_data_size(rb);
4613 void __weak arch_perf_update_userpage(
4614 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4619 * Callers need to ensure there can be no nesting of this function, otherwise
4620 * the seqlock logic goes bad. We can not serialize this because the arch
4621 * code calls this from NMI context.
4623 void perf_event_update_userpage(struct perf_event *event)
4625 struct perf_event_mmap_page *userpg;
4626 struct ring_buffer *rb;
4627 u64 enabled, running, now;
4630 rb = rcu_dereference(event->rb);
4635 * compute total_time_enabled, total_time_running
4636 * based on snapshot values taken when the event
4637 * was last scheduled in.
4639 * we cannot simply called update_context_time()
4640 * because of locking issue as we can be called in
4643 calc_timer_values(event, &now, &enabled, &running);
4645 userpg = rb->user_page;
4647 * Disable preemption so as to not let the corresponding user-space
4648 * spin too long if we get preempted.
4653 userpg->index = perf_event_index(event);
4654 userpg->offset = perf_event_count(event);
4656 userpg->offset -= local64_read(&event->hw.prev_count);
4658 userpg->time_enabled = enabled +
4659 atomic64_read(&event->child_total_time_enabled);
4661 userpg->time_running = running +
4662 atomic64_read(&event->child_total_time_running);
4664 arch_perf_update_userpage(event, userpg, now);
4673 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4675 struct perf_event *event = vma->vm_file->private_data;
4676 struct ring_buffer *rb;
4677 int ret = VM_FAULT_SIGBUS;
4679 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4680 if (vmf->pgoff == 0)
4686 rb = rcu_dereference(event->rb);
4690 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4693 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4697 get_page(vmf->page);
4698 vmf->page->mapping = vma->vm_file->f_mapping;
4699 vmf->page->index = vmf->pgoff;
4708 static void ring_buffer_attach(struct perf_event *event,
4709 struct ring_buffer *rb)
4711 struct ring_buffer *old_rb = NULL;
4712 unsigned long flags;
4716 * Should be impossible, we set this when removing
4717 * event->rb_entry and wait/clear when adding event->rb_entry.
4719 WARN_ON_ONCE(event->rcu_pending);
4722 spin_lock_irqsave(&old_rb->event_lock, flags);
4723 list_del_rcu(&event->rb_entry);
4724 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4726 event->rcu_batches = get_state_synchronize_rcu();
4727 event->rcu_pending = 1;
4731 if (event->rcu_pending) {
4732 cond_synchronize_rcu(event->rcu_batches);
4733 event->rcu_pending = 0;
4736 spin_lock_irqsave(&rb->event_lock, flags);
4737 list_add_rcu(&event->rb_entry, &rb->event_list);
4738 spin_unlock_irqrestore(&rb->event_lock, flags);
4741 rcu_assign_pointer(event->rb, rb);
4744 ring_buffer_put(old_rb);
4746 * Since we detached before setting the new rb, so that we
4747 * could attach the new rb, we could have missed a wakeup.
4750 wake_up_all(&event->waitq);
4754 static void ring_buffer_wakeup(struct perf_event *event)
4756 struct ring_buffer *rb;
4759 rb = rcu_dereference(event->rb);
4761 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4762 wake_up_all(&event->waitq);
4767 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4769 struct ring_buffer *rb;
4772 rb = rcu_dereference(event->rb);
4774 if (!atomic_inc_not_zero(&rb->refcount))
4782 void ring_buffer_put(struct ring_buffer *rb)
4784 if (!atomic_dec_and_test(&rb->refcount))
4787 WARN_ON_ONCE(!list_empty(&rb->event_list));
4789 call_rcu(&rb->rcu_head, rb_free_rcu);
4792 static void perf_mmap_open(struct vm_area_struct *vma)
4794 struct perf_event *event = vma->vm_file->private_data;
4796 atomic_inc(&event->mmap_count);
4797 atomic_inc(&event->rb->mmap_count);
4800 atomic_inc(&event->rb->aux_mmap_count);
4802 if (event->pmu->event_mapped)
4803 event->pmu->event_mapped(event);
4806 static void perf_pmu_output_stop(struct perf_event *event);
4809 * A buffer can be mmap()ed multiple times; either directly through the same
4810 * event, or through other events by use of perf_event_set_output().
4812 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4813 * the buffer here, where we still have a VM context. This means we need
4814 * to detach all events redirecting to us.
4816 static void perf_mmap_close(struct vm_area_struct *vma)
4818 struct perf_event *event = vma->vm_file->private_data;
4820 struct ring_buffer *rb = ring_buffer_get(event);
4821 struct user_struct *mmap_user = rb->mmap_user;
4822 int mmap_locked = rb->mmap_locked;
4823 unsigned long size = perf_data_size(rb);
4825 if (event->pmu->event_unmapped)
4826 event->pmu->event_unmapped(event);
4829 * rb->aux_mmap_count will always drop before rb->mmap_count and
4830 * event->mmap_count, so it is ok to use event->mmap_mutex to
4831 * serialize with perf_mmap here.
4833 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4834 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4836 * Stop all AUX events that are writing to this buffer,
4837 * so that we can free its AUX pages and corresponding PMU
4838 * data. Note that after rb::aux_mmap_count dropped to zero,
4839 * they won't start any more (see perf_aux_output_begin()).
4841 perf_pmu_output_stop(event);
4843 /* now it's safe to free the pages */
4844 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4845 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4847 /* this has to be the last one */
4849 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4851 mutex_unlock(&event->mmap_mutex);
4854 atomic_dec(&rb->mmap_count);
4856 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4859 ring_buffer_attach(event, NULL);
4860 mutex_unlock(&event->mmap_mutex);
4862 /* If there's still other mmap()s of this buffer, we're done. */
4863 if (atomic_read(&rb->mmap_count))
4867 * No other mmap()s, detach from all other events that might redirect
4868 * into the now unreachable buffer. Somewhat complicated by the
4869 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4873 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4874 if (!atomic_long_inc_not_zero(&event->refcount)) {
4876 * This event is en-route to free_event() which will
4877 * detach it and remove it from the list.
4883 mutex_lock(&event->mmap_mutex);
4885 * Check we didn't race with perf_event_set_output() which can
4886 * swizzle the rb from under us while we were waiting to
4887 * acquire mmap_mutex.
4889 * If we find a different rb; ignore this event, a next
4890 * iteration will no longer find it on the list. We have to
4891 * still restart the iteration to make sure we're not now
4892 * iterating the wrong list.
4894 if (event->rb == rb)
4895 ring_buffer_attach(event, NULL);
4897 mutex_unlock(&event->mmap_mutex);
4901 * Restart the iteration; either we're on the wrong list or
4902 * destroyed its integrity by doing a deletion.
4909 * It could be there's still a few 0-ref events on the list; they'll
4910 * get cleaned up by free_event() -- they'll also still have their
4911 * ref on the rb and will free it whenever they are done with it.
4913 * Aside from that, this buffer is 'fully' detached and unmapped,
4914 * undo the VM accounting.
4917 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4918 vma->vm_mm->pinned_vm -= mmap_locked;
4919 free_uid(mmap_user);
4922 ring_buffer_put(rb); /* could be last */
4925 static const struct vm_operations_struct perf_mmap_vmops = {
4926 .open = perf_mmap_open,
4927 .close = perf_mmap_close, /* non mergable */
4928 .fault = perf_mmap_fault,
4929 .page_mkwrite = perf_mmap_fault,
4932 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4934 struct perf_event *event = file->private_data;
4935 unsigned long user_locked, user_lock_limit;
4936 struct user_struct *user = current_user();
4937 unsigned long locked, lock_limit;
4938 struct ring_buffer *rb = NULL;
4939 unsigned long vma_size;
4940 unsigned long nr_pages;
4941 long user_extra = 0, extra = 0;
4942 int ret = 0, flags = 0;
4945 * Don't allow mmap() of inherited per-task counters. This would
4946 * create a performance issue due to all children writing to the
4949 if (event->cpu == -1 && event->attr.inherit)
4952 if (!(vma->vm_flags & VM_SHARED))
4955 vma_size = vma->vm_end - vma->vm_start;
4957 if (vma->vm_pgoff == 0) {
4958 nr_pages = (vma_size / PAGE_SIZE) - 1;
4961 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4962 * mapped, all subsequent mappings should have the same size
4963 * and offset. Must be above the normal perf buffer.
4965 u64 aux_offset, aux_size;
4970 nr_pages = vma_size / PAGE_SIZE;
4972 mutex_lock(&event->mmap_mutex);
4979 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4980 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4982 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4985 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4988 /* already mapped with a different offset */
4989 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4992 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4995 /* already mapped with a different size */
4996 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4999 if (!is_power_of_2(nr_pages))
5002 if (!atomic_inc_not_zero(&rb->mmap_count))
5005 if (rb_has_aux(rb)) {
5006 atomic_inc(&rb->aux_mmap_count);
5011 atomic_set(&rb->aux_mmap_count, 1);
5012 user_extra = nr_pages;
5018 * If we have rb pages ensure they're a power-of-two number, so we
5019 * can do bitmasks instead of modulo.
5021 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5024 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5027 WARN_ON_ONCE(event->ctx->parent_ctx);
5029 mutex_lock(&event->mmap_mutex);
5031 if (event->rb->nr_pages != nr_pages) {
5036 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5038 * Raced against perf_mmap_close() through
5039 * perf_event_set_output(). Try again, hope for better
5042 mutex_unlock(&event->mmap_mutex);
5049 user_extra = nr_pages + 1;
5052 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5055 * Increase the limit linearly with more CPUs:
5057 user_lock_limit *= num_online_cpus();
5059 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5061 if (user_locked > user_lock_limit)
5062 extra = user_locked - user_lock_limit;
5064 lock_limit = rlimit(RLIMIT_MEMLOCK);
5065 lock_limit >>= PAGE_SHIFT;
5066 locked = vma->vm_mm->pinned_vm + extra;
5068 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5069 !capable(CAP_IPC_LOCK)) {
5074 WARN_ON(!rb && event->rb);
5076 if (vma->vm_flags & VM_WRITE)
5077 flags |= RING_BUFFER_WRITABLE;
5080 rb = rb_alloc(nr_pages,
5081 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5089 atomic_set(&rb->mmap_count, 1);
5090 rb->mmap_user = get_current_user();
5091 rb->mmap_locked = extra;
5093 ring_buffer_attach(event, rb);
5095 perf_event_init_userpage(event);
5096 perf_event_update_userpage(event);
5098 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5099 event->attr.aux_watermark, flags);
5101 rb->aux_mmap_locked = extra;
5106 atomic_long_add(user_extra, &user->locked_vm);
5107 vma->vm_mm->pinned_vm += extra;
5109 atomic_inc(&event->mmap_count);
5111 atomic_dec(&rb->mmap_count);
5114 mutex_unlock(&event->mmap_mutex);
5117 * Since pinned accounting is per vm we cannot allow fork() to copy our
5120 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5121 vma->vm_ops = &perf_mmap_vmops;
5123 if (event->pmu->event_mapped)
5124 event->pmu->event_mapped(event);
5129 static int perf_fasync(int fd, struct file *filp, int on)
5131 struct inode *inode = file_inode(filp);
5132 struct perf_event *event = filp->private_data;
5136 retval = fasync_helper(fd, filp, on, &event->fasync);
5137 inode_unlock(inode);
5145 static const struct file_operations perf_fops = {
5146 .llseek = no_llseek,
5147 .release = perf_release,
5150 .unlocked_ioctl = perf_ioctl,
5151 .compat_ioctl = perf_compat_ioctl,
5153 .fasync = perf_fasync,
5159 * If there's data, ensure we set the poll() state and publish everything
5160 * to user-space before waking everybody up.
5163 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5165 /* only the parent has fasync state */
5167 event = event->parent;
5168 return &event->fasync;
5171 void perf_event_wakeup(struct perf_event *event)
5173 ring_buffer_wakeup(event);
5175 if (event->pending_kill) {
5176 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5177 event->pending_kill = 0;
5181 static void perf_pending_event(struct irq_work *entry)
5183 struct perf_event *event = container_of(entry,
5184 struct perf_event, pending);
5187 rctx = perf_swevent_get_recursion_context();
5189 * If we 'fail' here, that's OK, it means recursion is already disabled
5190 * and we won't recurse 'further'.
5193 if (event->pending_disable) {
5194 event->pending_disable = 0;
5195 perf_event_disable_local(event);
5198 if (event->pending_wakeup) {
5199 event->pending_wakeup = 0;
5200 perf_event_wakeup(event);
5204 perf_swevent_put_recursion_context(rctx);
5208 * We assume there is only KVM supporting the callbacks.
5209 * Later on, we might change it to a list if there is
5210 * another virtualization implementation supporting the callbacks.
5212 struct perf_guest_info_callbacks *perf_guest_cbs;
5214 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5216 perf_guest_cbs = cbs;
5219 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5221 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5223 perf_guest_cbs = NULL;
5226 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5229 perf_output_sample_regs(struct perf_output_handle *handle,
5230 struct pt_regs *regs, u64 mask)
5234 for_each_set_bit(bit, (const unsigned long *) &mask,
5235 sizeof(mask) * BITS_PER_BYTE) {
5238 val = perf_reg_value(regs, bit);
5239 perf_output_put(handle, val);
5243 static void perf_sample_regs_user(struct perf_regs *regs_user,
5244 struct pt_regs *regs,
5245 struct pt_regs *regs_user_copy)
5247 if (user_mode(regs)) {
5248 regs_user->abi = perf_reg_abi(current);
5249 regs_user->regs = regs;
5250 } else if (current->mm) {
5251 perf_get_regs_user(regs_user, regs, regs_user_copy);
5253 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5254 regs_user->regs = NULL;
5258 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5259 struct pt_regs *regs)
5261 regs_intr->regs = regs;
5262 regs_intr->abi = perf_reg_abi(current);
5267 * Get remaining task size from user stack pointer.
5269 * It'd be better to take stack vma map and limit this more
5270 * precisly, but there's no way to get it safely under interrupt,
5271 * so using TASK_SIZE as limit.
5273 static u64 perf_ustack_task_size(struct pt_regs *regs)
5275 unsigned long addr = perf_user_stack_pointer(regs);
5277 if (!addr || addr >= TASK_SIZE)
5280 return TASK_SIZE - addr;
5284 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5285 struct pt_regs *regs)
5289 /* No regs, no stack pointer, no dump. */
5294 * Check if we fit in with the requested stack size into the:
5296 * If we don't, we limit the size to the TASK_SIZE.
5298 * - remaining sample size
5299 * If we don't, we customize the stack size to
5300 * fit in to the remaining sample size.
5303 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5304 stack_size = min(stack_size, (u16) task_size);
5306 /* Current header size plus static size and dynamic size. */
5307 header_size += 2 * sizeof(u64);
5309 /* Do we fit in with the current stack dump size? */
5310 if ((u16) (header_size + stack_size) < header_size) {
5312 * If we overflow the maximum size for the sample,
5313 * we customize the stack dump size to fit in.
5315 stack_size = USHRT_MAX - header_size - sizeof(u64);
5316 stack_size = round_up(stack_size, sizeof(u64));
5323 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5324 struct pt_regs *regs)
5326 /* Case of a kernel thread, nothing to dump */
5329 perf_output_put(handle, size);
5338 * - the size requested by user or the best one we can fit
5339 * in to the sample max size
5341 * - user stack dump data
5343 * - the actual dumped size
5347 perf_output_put(handle, dump_size);
5350 sp = perf_user_stack_pointer(regs);
5351 rem = __output_copy_user(handle, (void *) sp, dump_size);
5352 dyn_size = dump_size - rem;
5354 perf_output_skip(handle, rem);
5357 perf_output_put(handle, dyn_size);
5361 static void __perf_event_header__init_id(struct perf_event_header *header,
5362 struct perf_sample_data *data,
5363 struct perf_event *event)
5365 u64 sample_type = event->attr.sample_type;
5367 data->type = sample_type;
5368 header->size += event->id_header_size;
5370 if (sample_type & PERF_SAMPLE_TID) {
5371 /* namespace issues */
5372 data->tid_entry.pid = perf_event_pid(event, current);
5373 data->tid_entry.tid = perf_event_tid(event, current);
5376 if (sample_type & PERF_SAMPLE_TIME)
5377 data->time = perf_event_clock(event);
5379 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5380 data->id = primary_event_id(event);
5382 if (sample_type & PERF_SAMPLE_STREAM_ID)
5383 data->stream_id = event->id;
5385 if (sample_type & PERF_SAMPLE_CPU) {
5386 data->cpu_entry.cpu = raw_smp_processor_id();
5387 data->cpu_entry.reserved = 0;
5391 void perf_event_header__init_id(struct perf_event_header *header,
5392 struct perf_sample_data *data,
5393 struct perf_event *event)
5395 if (event->attr.sample_id_all)
5396 __perf_event_header__init_id(header, data, event);
5399 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5400 struct perf_sample_data *data)
5402 u64 sample_type = data->type;
5404 if (sample_type & PERF_SAMPLE_TID)
5405 perf_output_put(handle, data->tid_entry);
5407 if (sample_type & PERF_SAMPLE_TIME)
5408 perf_output_put(handle, data->time);
5410 if (sample_type & PERF_SAMPLE_ID)
5411 perf_output_put(handle, data->id);
5413 if (sample_type & PERF_SAMPLE_STREAM_ID)
5414 perf_output_put(handle, data->stream_id);
5416 if (sample_type & PERF_SAMPLE_CPU)
5417 perf_output_put(handle, data->cpu_entry);
5419 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5420 perf_output_put(handle, data->id);
5423 void perf_event__output_id_sample(struct perf_event *event,
5424 struct perf_output_handle *handle,
5425 struct perf_sample_data *sample)
5427 if (event->attr.sample_id_all)
5428 __perf_event__output_id_sample(handle, sample);
5431 static void perf_output_read_one(struct perf_output_handle *handle,
5432 struct perf_event *event,
5433 u64 enabled, u64 running)
5435 u64 read_format = event->attr.read_format;
5439 values[n++] = perf_event_count(event);
5440 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5441 values[n++] = enabled +
5442 atomic64_read(&event->child_total_time_enabled);
5444 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5445 values[n++] = running +
5446 atomic64_read(&event->child_total_time_running);
5448 if (read_format & PERF_FORMAT_ID)
5449 values[n++] = primary_event_id(event);
5451 __output_copy(handle, values, n * sizeof(u64));
5455 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5457 static void perf_output_read_group(struct perf_output_handle *handle,
5458 struct perf_event *event,
5459 u64 enabled, u64 running)
5461 struct perf_event *leader = event->group_leader, *sub;
5462 u64 read_format = event->attr.read_format;
5466 values[n++] = 1 + leader->nr_siblings;
5468 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5469 values[n++] = enabled;
5471 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5472 values[n++] = running;
5474 if (leader != event)
5475 leader->pmu->read(leader);
5477 values[n++] = perf_event_count(leader);
5478 if (read_format & PERF_FORMAT_ID)
5479 values[n++] = primary_event_id(leader);
5481 __output_copy(handle, values, n * sizeof(u64));
5483 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5486 if ((sub != event) &&
5487 (sub->state == PERF_EVENT_STATE_ACTIVE))
5488 sub->pmu->read(sub);
5490 values[n++] = perf_event_count(sub);
5491 if (read_format & PERF_FORMAT_ID)
5492 values[n++] = primary_event_id(sub);
5494 __output_copy(handle, values, n * sizeof(u64));
5498 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5499 PERF_FORMAT_TOTAL_TIME_RUNNING)
5501 static void perf_output_read(struct perf_output_handle *handle,
5502 struct perf_event *event)
5504 u64 enabled = 0, running = 0, now;
5505 u64 read_format = event->attr.read_format;
5508 * compute total_time_enabled, total_time_running
5509 * based on snapshot values taken when the event
5510 * was last scheduled in.
5512 * we cannot simply called update_context_time()
5513 * because of locking issue as we are called in
5516 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5517 calc_timer_values(event, &now, &enabled, &running);
5519 if (event->attr.read_format & PERF_FORMAT_GROUP)
5520 perf_output_read_group(handle, event, enabled, running);
5522 perf_output_read_one(handle, event, enabled, running);
5525 void perf_output_sample(struct perf_output_handle *handle,
5526 struct perf_event_header *header,
5527 struct perf_sample_data *data,
5528 struct perf_event *event)
5530 u64 sample_type = data->type;
5532 perf_output_put(handle, *header);
5534 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5535 perf_output_put(handle, data->id);
5537 if (sample_type & PERF_SAMPLE_IP)
5538 perf_output_put(handle, data->ip);
5540 if (sample_type & PERF_SAMPLE_TID)
5541 perf_output_put(handle, data->tid_entry);
5543 if (sample_type & PERF_SAMPLE_TIME)
5544 perf_output_put(handle, data->time);
5546 if (sample_type & PERF_SAMPLE_ADDR)
5547 perf_output_put(handle, data->addr);
5549 if (sample_type & PERF_SAMPLE_ID)
5550 perf_output_put(handle, data->id);
5552 if (sample_type & PERF_SAMPLE_STREAM_ID)
5553 perf_output_put(handle, data->stream_id);
5555 if (sample_type & PERF_SAMPLE_CPU)
5556 perf_output_put(handle, data->cpu_entry);
5558 if (sample_type & PERF_SAMPLE_PERIOD)
5559 perf_output_put(handle, data->period);
5561 if (sample_type & PERF_SAMPLE_READ)
5562 perf_output_read(handle, event);
5564 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5565 if (data->callchain) {
5568 if (data->callchain)
5569 size += data->callchain->nr;
5571 size *= sizeof(u64);
5573 __output_copy(handle, data->callchain, size);
5576 perf_output_put(handle, nr);
5580 if (sample_type & PERF_SAMPLE_RAW) {
5582 u32 raw_size = data->raw->size;
5583 u32 real_size = round_up(raw_size + sizeof(u32),
5584 sizeof(u64)) - sizeof(u32);
5587 perf_output_put(handle, real_size);
5588 __output_copy(handle, data->raw->data, raw_size);
5589 if (real_size - raw_size)
5590 __output_copy(handle, &zero, real_size - raw_size);
5596 .size = sizeof(u32),
5599 perf_output_put(handle, raw);
5603 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5604 if (data->br_stack) {
5607 size = data->br_stack->nr
5608 * sizeof(struct perf_branch_entry);
5610 perf_output_put(handle, data->br_stack->nr);
5611 perf_output_copy(handle, data->br_stack->entries, size);
5614 * we always store at least the value of nr
5617 perf_output_put(handle, nr);
5621 if (sample_type & PERF_SAMPLE_REGS_USER) {
5622 u64 abi = data->regs_user.abi;
5625 * If there are no regs to dump, notice it through
5626 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5628 perf_output_put(handle, abi);
5631 u64 mask = event->attr.sample_regs_user;
5632 perf_output_sample_regs(handle,
5633 data->regs_user.regs,
5638 if (sample_type & PERF_SAMPLE_STACK_USER) {
5639 perf_output_sample_ustack(handle,
5640 data->stack_user_size,
5641 data->regs_user.regs);
5644 if (sample_type & PERF_SAMPLE_WEIGHT)
5645 perf_output_put(handle, data->weight);
5647 if (sample_type & PERF_SAMPLE_DATA_SRC)
5648 perf_output_put(handle, data->data_src.val);
5650 if (sample_type & PERF_SAMPLE_TRANSACTION)
5651 perf_output_put(handle, data->txn);
5653 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5654 u64 abi = data->regs_intr.abi;
5656 * If there are no regs to dump, notice it through
5657 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5659 perf_output_put(handle, abi);
5662 u64 mask = event->attr.sample_regs_intr;
5664 perf_output_sample_regs(handle,
5665 data->regs_intr.regs,
5670 if (!event->attr.watermark) {
5671 int wakeup_events = event->attr.wakeup_events;
5673 if (wakeup_events) {
5674 struct ring_buffer *rb = handle->rb;
5675 int events = local_inc_return(&rb->events);
5677 if (events >= wakeup_events) {
5678 local_sub(wakeup_events, &rb->events);
5679 local_inc(&rb->wakeup);
5685 void perf_prepare_sample(struct perf_event_header *header,
5686 struct perf_sample_data *data,
5687 struct perf_event *event,
5688 struct pt_regs *regs)
5690 u64 sample_type = event->attr.sample_type;
5692 header->type = PERF_RECORD_SAMPLE;
5693 header->size = sizeof(*header) + event->header_size;
5696 header->misc |= perf_misc_flags(regs);
5698 __perf_event_header__init_id(header, data, event);
5700 if (sample_type & PERF_SAMPLE_IP)
5701 data->ip = perf_instruction_pointer(regs);
5703 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5706 data->callchain = perf_callchain(event, regs);
5708 if (data->callchain)
5709 size += data->callchain->nr;
5711 header->size += size * sizeof(u64);
5714 if (sample_type & PERF_SAMPLE_RAW) {
5715 int size = sizeof(u32);
5718 size += data->raw->size;
5720 size += sizeof(u32);
5722 header->size += round_up(size, sizeof(u64));
5725 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5726 int size = sizeof(u64); /* nr */
5727 if (data->br_stack) {
5728 size += data->br_stack->nr
5729 * sizeof(struct perf_branch_entry);
5731 header->size += size;
5734 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5735 perf_sample_regs_user(&data->regs_user, regs,
5736 &data->regs_user_copy);
5738 if (sample_type & PERF_SAMPLE_REGS_USER) {
5739 /* regs dump ABI info */
5740 int size = sizeof(u64);
5742 if (data->regs_user.regs) {
5743 u64 mask = event->attr.sample_regs_user;
5744 size += hweight64(mask) * sizeof(u64);
5747 header->size += size;
5750 if (sample_type & PERF_SAMPLE_STACK_USER) {
5752 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5753 * processed as the last one or have additional check added
5754 * in case new sample type is added, because we could eat
5755 * up the rest of the sample size.
5757 u16 stack_size = event->attr.sample_stack_user;
5758 u16 size = sizeof(u64);
5760 stack_size = perf_sample_ustack_size(stack_size, header->size,
5761 data->regs_user.regs);
5764 * If there is something to dump, add space for the dump
5765 * itself and for the field that tells the dynamic size,
5766 * which is how many have been actually dumped.
5769 size += sizeof(u64) + stack_size;
5771 data->stack_user_size = stack_size;
5772 header->size += size;
5775 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5776 /* regs dump ABI info */
5777 int size = sizeof(u64);
5779 perf_sample_regs_intr(&data->regs_intr, regs);
5781 if (data->regs_intr.regs) {
5782 u64 mask = event->attr.sample_regs_intr;
5784 size += hweight64(mask) * sizeof(u64);
5787 header->size += size;
5791 static void __always_inline
5792 __perf_event_output(struct perf_event *event,
5793 struct perf_sample_data *data,
5794 struct pt_regs *regs,
5795 int (*output_begin)(struct perf_output_handle *,
5796 struct perf_event *,
5799 struct perf_output_handle handle;
5800 struct perf_event_header header;
5802 /* protect the callchain buffers */
5805 perf_prepare_sample(&header, data, event, regs);
5807 if (output_begin(&handle, event, header.size))
5810 perf_output_sample(&handle, &header, data, event);
5812 perf_output_end(&handle);
5819 perf_event_output_forward(struct perf_event *event,
5820 struct perf_sample_data *data,
5821 struct pt_regs *regs)
5823 __perf_event_output(event, data, regs, perf_output_begin_forward);
5827 perf_event_output_backward(struct perf_event *event,
5828 struct perf_sample_data *data,
5829 struct pt_regs *regs)
5831 __perf_event_output(event, data, regs, perf_output_begin_backward);
5835 perf_event_output(struct perf_event *event,
5836 struct perf_sample_data *data,
5837 struct pt_regs *regs)
5839 __perf_event_output(event, data, regs, perf_output_begin);
5846 struct perf_read_event {
5847 struct perf_event_header header;
5854 perf_event_read_event(struct perf_event *event,
5855 struct task_struct *task)
5857 struct perf_output_handle handle;
5858 struct perf_sample_data sample;
5859 struct perf_read_event read_event = {
5861 .type = PERF_RECORD_READ,
5863 .size = sizeof(read_event) + event->read_size,
5865 .pid = perf_event_pid(event, task),
5866 .tid = perf_event_tid(event, task),
5870 perf_event_header__init_id(&read_event.header, &sample, event);
5871 ret = perf_output_begin(&handle, event, read_event.header.size);
5875 perf_output_put(&handle, read_event);
5876 perf_output_read(&handle, event);
5877 perf_event__output_id_sample(event, &handle, &sample);
5879 perf_output_end(&handle);
5882 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5885 perf_event_aux_ctx(struct perf_event_context *ctx,
5886 perf_event_aux_output_cb output,
5887 void *data, bool all)
5889 struct perf_event *event;
5891 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5893 if (event->state < PERF_EVENT_STATE_INACTIVE)
5895 if (!event_filter_match(event))
5899 output(event, data);
5904 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5905 struct perf_event_context *task_ctx)
5909 perf_event_aux_ctx(task_ctx, output, data, false);
5914 static void perf_event_sb_iterate(perf_event_aux_output_cb output, void *data)
5916 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
5917 struct perf_event *event;
5919 list_for_each_entry_rcu(event, &pel->list, sb_list) {
5920 if (event->state < PERF_EVENT_STATE_INACTIVE)
5922 if (!event_filter_match(event))
5924 output(event, data);
5929 perf_event_aux(perf_event_aux_output_cb output, void *data,
5930 struct perf_event_context *task_ctx)
5932 struct perf_event_context *ctx;
5936 * If we have task_ctx != NULL we only notify
5937 * the task context itself. The task_ctx is set
5938 * only for EXIT events before releasing task
5942 perf_event_aux_task_ctx(output, data, task_ctx);
5948 perf_event_sb_iterate(output, data);
5950 for_each_task_context_nr(ctxn) {
5951 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5953 perf_event_aux_ctx(ctx, output, data, false);
5960 * Clear all file-based filters at exec, they'll have to be
5961 * re-instated when/if these objects are mmapped again.
5963 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
5965 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
5966 struct perf_addr_filter *filter;
5967 unsigned int restart = 0, count = 0;
5968 unsigned long flags;
5970 if (!has_addr_filter(event))
5973 raw_spin_lock_irqsave(&ifh->lock, flags);
5974 list_for_each_entry(filter, &ifh->list, entry) {
5975 if (filter->inode) {
5976 event->addr_filters_offs[count] = 0;
5984 event->addr_filters_gen++;
5985 raw_spin_unlock_irqrestore(&ifh->lock, flags);
5988 perf_event_restart(event);
5991 void perf_event_exec(void)
5993 struct perf_event_context *ctx;
5997 for_each_task_context_nr(ctxn) {
5998 ctx = current->perf_event_ctxp[ctxn];
6002 perf_event_enable_on_exec(ctxn);
6004 perf_event_aux_ctx(ctx, perf_event_addr_filters_exec, NULL,
6010 struct remote_output {
6011 struct ring_buffer *rb;
6015 static void __perf_event_output_stop(struct perf_event *event, void *data)
6017 struct perf_event *parent = event->parent;
6018 struct remote_output *ro = data;
6019 struct ring_buffer *rb = ro->rb;
6020 struct stop_event_data sd = {
6024 if (!has_aux(event))
6031 * In case of inheritance, it will be the parent that links to the
6032 * ring-buffer, but it will be the child that's actually using it:
6034 if (rcu_dereference(parent->rb) == rb)
6035 ro->err = __perf_event_stop(&sd);
6038 static int __perf_pmu_output_stop(void *info)
6040 struct perf_event *event = info;
6041 struct pmu *pmu = event->pmu;
6042 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
6043 struct remote_output ro = {
6048 perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6049 if (cpuctx->task_ctx)
6050 perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6057 static void perf_pmu_output_stop(struct perf_event *event)
6059 struct perf_event *iter;
6064 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6066 * For per-CPU events, we need to make sure that neither they
6067 * nor their children are running; for cpu==-1 events it's
6068 * sufficient to stop the event itself if it's active, since
6069 * it can't have children.
6073 cpu = READ_ONCE(iter->oncpu);
6078 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6079 if (err == -EAGAIN) {
6088 * task tracking -- fork/exit
6090 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6093 struct perf_task_event {
6094 struct task_struct *task;
6095 struct perf_event_context *task_ctx;
6098 struct perf_event_header header;
6108 static int perf_event_task_match(struct perf_event *event)
6110 return event->attr.comm || event->attr.mmap ||
6111 event->attr.mmap2 || event->attr.mmap_data ||
6115 static void perf_event_task_output(struct perf_event *event,
6118 struct perf_task_event *task_event = data;
6119 struct perf_output_handle handle;
6120 struct perf_sample_data sample;
6121 struct task_struct *task = task_event->task;
6122 int ret, size = task_event->event_id.header.size;
6124 if (!perf_event_task_match(event))
6127 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6129 ret = perf_output_begin(&handle, event,
6130 task_event->event_id.header.size);
6134 task_event->event_id.pid = perf_event_pid(event, task);
6135 task_event->event_id.ppid = perf_event_pid(event, current);
6137 task_event->event_id.tid = perf_event_tid(event, task);
6138 task_event->event_id.ptid = perf_event_tid(event, current);
6140 task_event->event_id.time = perf_event_clock(event);
6142 perf_output_put(&handle, task_event->event_id);
6144 perf_event__output_id_sample(event, &handle, &sample);
6146 perf_output_end(&handle);
6148 task_event->event_id.header.size = size;
6151 static void perf_event_task(struct task_struct *task,
6152 struct perf_event_context *task_ctx,
6155 struct perf_task_event task_event;
6157 if (!atomic_read(&nr_comm_events) &&
6158 !atomic_read(&nr_mmap_events) &&
6159 !atomic_read(&nr_task_events))
6162 task_event = (struct perf_task_event){
6164 .task_ctx = task_ctx,
6167 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6169 .size = sizeof(task_event.event_id),
6179 perf_event_aux(perf_event_task_output,
6184 void perf_event_fork(struct task_struct *task)
6186 perf_event_task(task, NULL, 1);
6193 struct perf_comm_event {
6194 struct task_struct *task;
6199 struct perf_event_header header;
6206 static int perf_event_comm_match(struct perf_event *event)
6208 return event->attr.comm;
6211 static void perf_event_comm_output(struct perf_event *event,
6214 struct perf_comm_event *comm_event = data;
6215 struct perf_output_handle handle;
6216 struct perf_sample_data sample;
6217 int size = comm_event->event_id.header.size;
6220 if (!perf_event_comm_match(event))
6223 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6224 ret = perf_output_begin(&handle, event,
6225 comm_event->event_id.header.size);
6230 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6231 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6233 perf_output_put(&handle, comm_event->event_id);
6234 __output_copy(&handle, comm_event->comm,
6235 comm_event->comm_size);
6237 perf_event__output_id_sample(event, &handle, &sample);
6239 perf_output_end(&handle);
6241 comm_event->event_id.header.size = size;
6244 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6246 char comm[TASK_COMM_LEN];
6249 memset(comm, 0, sizeof(comm));
6250 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6251 size = ALIGN(strlen(comm)+1, sizeof(u64));
6253 comm_event->comm = comm;
6254 comm_event->comm_size = size;
6256 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6258 perf_event_aux(perf_event_comm_output,
6263 void perf_event_comm(struct task_struct *task, bool exec)
6265 struct perf_comm_event comm_event;
6267 if (!atomic_read(&nr_comm_events))
6270 comm_event = (struct perf_comm_event){
6276 .type = PERF_RECORD_COMM,
6277 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6285 perf_event_comm_event(&comm_event);
6292 struct perf_mmap_event {
6293 struct vm_area_struct *vma;
6295 const char *file_name;
6303 struct perf_event_header header;
6313 static int perf_event_mmap_match(struct perf_event *event,
6316 struct perf_mmap_event *mmap_event = data;
6317 struct vm_area_struct *vma = mmap_event->vma;
6318 int executable = vma->vm_flags & VM_EXEC;
6320 return (!executable && event->attr.mmap_data) ||
6321 (executable && (event->attr.mmap || event->attr.mmap2));
6324 static void perf_event_mmap_output(struct perf_event *event,
6327 struct perf_mmap_event *mmap_event = data;
6328 struct perf_output_handle handle;
6329 struct perf_sample_data sample;
6330 int size = mmap_event->event_id.header.size;
6333 if (!perf_event_mmap_match(event, data))
6336 if (event->attr.mmap2) {
6337 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6338 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6339 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6340 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6341 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6342 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6343 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6346 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6347 ret = perf_output_begin(&handle, event,
6348 mmap_event->event_id.header.size);
6352 mmap_event->event_id.pid = perf_event_pid(event, current);
6353 mmap_event->event_id.tid = perf_event_tid(event, current);
6355 perf_output_put(&handle, mmap_event->event_id);
6357 if (event->attr.mmap2) {
6358 perf_output_put(&handle, mmap_event->maj);
6359 perf_output_put(&handle, mmap_event->min);
6360 perf_output_put(&handle, mmap_event->ino);
6361 perf_output_put(&handle, mmap_event->ino_generation);
6362 perf_output_put(&handle, mmap_event->prot);
6363 perf_output_put(&handle, mmap_event->flags);
6366 __output_copy(&handle, mmap_event->file_name,
6367 mmap_event->file_size);
6369 perf_event__output_id_sample(event, &handle, &sample);
6371 perf_output_end(&handle);
6373 mmap_event->event_id.header.size = size;
6376 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6378 struct vm_area_struct *vma = mmap_event->vma;
6379 struct file *file = vma->vm_file;
6380 int maj = 0, min = 0;
6381 u64 ino = 0, gen = 0;
6382 u32 prot = 0, flags = 0;
6389 struct inode *inode;
6392 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6398 * d_path() works from the end of the rb backwards, so we
6399 * need to add enough zero bytes after the string to handle
6400 * the 64bit alignment we do later.
6402 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6407 inode = file_inode(vma->vm_file);
6408 dev = inode->i_sb->s_dev;
6410 gen = inode->i_generation;
6414 if (vma->vm_flags & VM_READ)
6416 if (vma->vm_flags & VM_WRITE)
6418 if (vma->vm_flags & VM_EXEC)
6421 if (vma->vm_flags & VM_MAYSHARE)
6424 flags = MAP_PRIVATE;
6426 if (vma->vm_flags & VM_DENYWRITE)
6427 flags |= MAP_DENYWRITE;
6428 if (vma->vm_flags & VM_MAYEXEC)
6429 flags |= MAP_EXECUTABLE;
6430 if (vma->vm_flags & VM_LOCKED)
6431 flags |= MAP_LOCKED;
6432 if (vma->vm_flags & VM_HUGETLB)
6433 flags |= MAP_HUGETLB;
6437 if (vma->vm_ops && vma->vm_ops->name) {
6438 name = (char *) vma->vm_ops->name(vma);
6443 name = (char *)arch_vma_name(vma);
6447 if (vma->vm_start <= vma->vm_mm->start_brk &&
6448 vma->vm_end >= vma->vm_mm->brk) {
6452 if (vma->vm_start <= vma->vm_mm->start_stack &&
6453 vma->vm_end >= vma->vm_mm->start_stack) {
6463 strlcpy(tmp, name, sizeof(tmp));
6467 * Since our buffer works in 8 byte units we need to align our string
6468 * size to a multiple of 8. However, we must guarantee the tail end is
6469 * zero'd out to avoid leaking random bits to userspace.
6471 size = strlen(name)+1;
6472 while (!IS_ALIGNED(size, sizeof(u64)))
6473 name[size++] = '\0';
6475 mmap_event->file_name = name;
6476 mmap_event->file_size = size;
6477 mmap_event->maj = maj;
6478 mmap_event->min = min;
6479 mmap_event->ino = ino;
6480 mmap_event->ino_generation = gen;
6481 mmap_event->prot = prot;
6482 mmap_event->flags = flags;
6484 if (!(vma->vm_flags & VM_EXEC))
6485 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6487 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6489 perf_event_aux(perf_event_mmap_output,
6497 * Whether this @filter depends on a dynamic object which is not loaded
6498 * yet or its load addresses are not known.
6500 static bool perf_addr_filter_needs_mmap(struct perf_addr_filter *filter)
6502 return filter->filter && filter->inode;
6506 * Check whether inode and address range match filter criteria.
6508 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6509 struct file *file, unsigned long offset,
6512 if (filter->inode != file->f_inode)
6515 if (filter->offset > offset + size)
6518 if (filter->offset + filter->size < offset)
6524 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6526 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6527 struct vm_area_struct *vma = data;
6528 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6529 struct file *file = vma->vm_file;
6530 struct perf_addr_filter *filter;
6531 unsigned int restart = 0, count = 0;
6533 if (!has_addr_filter(event))
6539 raw_spin_lock_irqsave(&ifh->lock, flags);
6540 list_for_each_entry(filter, &ifh->list, entry) {
6541 if (perf_addr_filter_match(filter, file, off,
6542 vma->vm_end - vma->vm_start)) {
6543 event->addr_filters_offs[count] = vma->vm_start;
6551 event->addr_filters_gen++;
6552 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6555 perf_event_restart(event);
6559 * Adjust all task's events' filters to the new vma
6561 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6563 struct perf_event_context *ctx;
6567 for_each_task_context_nr(ctxn) {
6568 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6572 perf_event_aux_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6577 void perf_event_mmap(struct vm_area_struct *vma)
6579 struct perf_mmap_event mmap_event;
6581 if (!atomic_read(&nr_mmap_events))
6584 mmap_event = (struct perf_mmap_event){
6590 .type = PERF_RECORD_MMAP,
6591 .misc = PERF_RECORD_MISC_USER,
6596 .start = vma->vm_start,
6597 .len = vma->vm_end - vma->vm_start,
6598 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6600 /* .maj (attr_mmap2 only) */
6601 /* .min (attr_mmap2 only) */
6602 /* .ino (attr_mmap2 only) */
6603 /* .ino_generation (attr_mmap2 only) */
6604 /* .prot (attr_mmap2 only) */
6605 /* .flags (attr_mmap2 only) */
6608 perf_addr_filters_adjust(vma);
6609 perf_event_mmap_event(&mmap_event);
6612 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6613 unsigned long size, u64 flags)
6615 struct perf_output_handle handle;
6616 struct perf_sample_data sample;
6617 struct perf_aux_event {
6618 struct perf_event_header header;
6624 .type = PERF_RECORD_AUX,
6626 .size = sizeof(rec),
6634 perf_event_header__init_id(&rec.header, &sample, event);
6635 ret = perf_output_begin(&handle, event, rec.header.size);
6640 perf_output_put(&handle, rec);
6641 perf_event__output_id_sample(event, &handle, &sample);
6643 perf_output_end(&handle);
6647 * Lost/dropped samples logging
6649 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6651 struct perf_output_handle handle;
6652 struct perf_sample_data sample;
6656 struct perf_event_header header;
6658 } lost_samples_event = {
6660 .type = PERF_RECORD_LOST_SAMPLES,
6662 .size = sizeof(lost_samples_event),
6667 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6669 ret = perf_output_begin(&handle, event,
6670 lost_samples_event.header.size);
6674 perf_output_put(&handle, lost_samples_event);
6675 perf_event__output_id_sample(event, &handle, &sample);
6676 perf_output_end(&handle);
6680 * context_switch tracking
6683 struct perf_switch_event {
6684 struct task_struct *task;
6685 struct task_struct *next_prev;
6688 struct perf_event_header header;
6694 static int perf_event_switch_match(struct perf_event *event)
6696 return event->attr.context_switch;
6699 static void perf_event_switch_output(struct perf_event *event, void *data)
6701 struct perf_switch_event *se = data;
6702 struct perf_output_handle handle;
6703 struct perf_sample_data sample;
6706 if (!perf_event_switch_match(event))
6709 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6710 if (event->ctx->task) {
6711 se->event_id.header.type = PERF_RECORD_SWITCH;
6712 se->event_id.header.size = sizeof(se->event_id.header);
6714 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6715 se->event_id.header.size = sizeof(se->event_id);
6716 se->event_id.next_prev_pid =
6717 perf_event_pid(event, se->next_prev);
6718 se->event_id.next_prev_tid =
6719 perf_event_tid(event, se->next_prev);
6722 perf_event_header__init_id(&se->event_id.header, &sample, event);
6724 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6728 if (event->ctx->task)
6729 perf_output_put(&handle, se->event_id.header);
6731 perf_output_put(&handle, se->event_id);
6733 perf_event__output_id_sample(event, &handle, &sample);
6735 perf_output_end(&handle);
6738 static void perf_event_switch(struct task_struct *task,
6739 struct task_struct *next_prev, bool sched_in)
6741 struct perf_switch_event switch_event;
6743 /* N.B. caller checks nr_switch_events != 0 */
6745 switch_event = (struct perf_switch_event){
6747 .next_prev = next_prev,
6751 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6754 /* .next_prev_pid */
6755 /* .next_prev_tid */
6759 perf_event_aux(perf_event_switch_output,
6765 * IRQ throttle logging
6768 static void perf_log_throttle(struct perf_event *event, int enable)
6770 struct perf_output_handle handle;
6771 struct perf_sample_data sample;
6775 struct perf_event_header header;
6779 } throttle_event = {
6781 .type = PERF_RECORD_THROTTLE,
6783 .size = sizeof(throttle_event),
6785 .time = perf_event_clock(event),
6786 .id = primary_event_id(event),
6787 .stream_id = event->id,
6791 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6793 perf_event_header__init_id(&throttle_event.header, &sample, event);
6795 ret = perf_output_begin(&handle, event,
6796 throttle_event.header.size);
6800 perf_output_put(&handle, throttle_event);
6801 perf_event__output_id_sample(event, &handle, &sample);
6802 perf_output_end(&handle);
6805 static void perf_log_itrace_start(struct perf_event *event)
6807 struct perf_output_handle handle;
6808 struct perf_sample_data sample;
6809 struct perf_aux_event {
6810 struct perf_event_header header;
6817 event = event->parent;
6819 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6820 event->hw.itrace_started)
6823 rec.header.type = PERF_RECORD_ITRACE_START;
6824 rec.header.misc = 0;
6825 rec.header.size = sizeof(rec);
6826 rec.pid = perf_event_pid(event, current);
6827 rec.tid = perf_event_tid(event, current);
6829 perf_event_header__init_id(&rec.header, &sample, event);
6830 ret = perf_output_begin(&handle, event, rec.header.size);
6835 perf_output_put(&handle, rec);
6836 perf_event__output_id_sample(event, &handle, &sample);
6838 perf_output_end(&handle);
6842 * Generic event overflow handling, sampling.
6845 static int __perf_event_overflow(struct perf_event *event,
6846 int throttle, struct perf_sample_data *data,
6847 struct pt_regs *regs)
6849 int events = atomic_read(&event->event_limit);
6850 struct hw_perf_event *hwc = &event->hw;
6855 * Non-sampling counters might still use the PMI to fold short
6856 * hardware counters, ignore those.
6858 if (unlikely(!is_sampling_event(event)))
6861 seq = __this_cpu_read(perf_throttled_seq);
6862 if (seq != hwc->interrupts_seq) {
6863 hwc->interrupts_seq = seq;
6864 hwc->interrupts = 1;
6867 if (unlikely(throttle
6868 && hwc->interrupts >= max_samples_per_tick)) {
6869 __this_cpu_inc(perf_throttled_count);
6870 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
6871 hwc->interrupts = MAX_INTERRUPTS;
6872 perf_log_throttle(event, 0);
6877 if (event->attr.freq) {
6878 u64 now = perf_clock();
6879 s64 delta = now - hwc->freq_time_stamp;
6881 hwc->freq_time_stamp = now;
6883 if (delta > 0 && delta < 2*TICK_NSEC)
6884 perf_adjust_period(event, delta, hwc->last_period, true);
6888 * XXX event_limit might not quite work as expected on inherited
6892 event->pending_kill = POLL_IN;
6893 if (events && atomic_dec_and_test(&event->event_limit)) {
6895 event->pending_kill = POLL_HUP;
6896 event->pending_disable = 1;
6897 irq_work_queue(&event->pending);
6900 event->overflow_handler(event, data, regs);
6902 if (*perf_event_fasync(event) && event->pending_kill) {
6903 event->pending_wakeup = 1;
6904 irq_work_queue(&event->pending);
6910 int perf_event_overflow(struct perf_event *event,
6911 struct perf_sample_data *data,
6912 struct pt_regs *regs)
6914 return __perf_event_overflow(event, 1, data, regs);
6918 * Generic software event infrastructure
6921 struct swevent_htable {
6922 struct swevent_hlist *swevent_hlist;
6923 struct mutex hlist_mutex;
6926 /* Recursion avoidance in each contexts */
6927 int recursion[PERF_NR_CONTEXTS];
6930 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6933 * We directly increment event->count and keep a second value in
6934 * event->hw.period_left to count intervals. This period event
6935 * is kept in the range [-sample_period, 0] so that we can use the
6939 u64 perf_swevent_set_period(struct perf_event *event)
6941 struct hw_perf_event *hwc = &event->hw;
6942 u64 period = hwc->last_period;
6946 hwc->last_period = hwc->sample_period;
6949 old = val = local64_read(&hwc->period_left);
6953 nr = div64_u64(period + val, period);
6954 offset = nr * period;
6956 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6962 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6963 struct perf_sample_data *data,
6964 struct pt_regs *regs)
6966 struct hw_perf_event *hwc = &event->hw;
6970 overflow = perf_swevent_set_period(event);
6972 if (hwc->interrupts == MAX_INTERRUPTS)
6975 for (; overflow; overflow--) {
6976 if (__perf_event_overflow(event, throttle,
6979 * We inhibit the overflow from happening when
6980 * hwc->interrupts == MAX_INTERRUPTS.
6988 static void perf_swevent_event(struct perf_event *event, u64 nr,
6989 struct perf_sample_data *data,
6990 struct pt_regs *regs)
6992 struct hw_perf_event *hwc = &event->hw;
6994 local64_add(nr, &event->count);
6999 if (!is_sampling_event(event))
7002 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7004 return perf_swevent_overflow(event, 1, data, regs);
7006 data->period = event->hw.last_period;
7008 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7009 return perf_swevent_overflow(event, 1, data, regs);
7011 if (local64_add_negative(nr, &hwc->period_left))
7014 perf_swevent_overflow(event, 0, data, regs);
7017 static int perf_exclude_event(struct perf_event *event,
7018 struct pt_regs *regs)
7020 if (event->hw.state & PERF_HES_STOPPED)
7024 if (event->attr.exclude_user && user_mode(regs))
7027 if (event->attr.exclude_kernel && !user_mode(regs))
7034 static int perf_swevent_match(struct perf_event *event,
7035 enum perf_type_id type,
7037 struct perf_sample_data *data,
7038 struct pt_regs *regs)
7040 if (event->attr.type != type)
7043 if (event->attr.config != event_id)
7046 if (perf_exclude_event(event, regs))
7052 static inline u64 swevent_hash(u64 type, u32 event_id)
7054 u64 val = event_id | (type << 32);
7056 return hash_64(val, SWEVENT_HLIST_BITS);
7059 static inline struct hlist_head *
7060 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7062 u64 hash = swevent_hash(type, event_id);
7064 return &hlist->heads[hash];
7067 /* For the read side: events when they trigger */
7068 static inline struct hlist_head *
7069 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7071 struct swevent_hlist *hlist;
7073 hlist = rcu_dereference(swhash->swevent_hlist);
7077 return __find_swevent_head(hlist, type, event_id);
7080 /* For the event head insertion and removal in the hlist */
7081 static inline struct hlist_head *
7082 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7084 struct swevent_hlist *hlist;
7085 u32 event_id = event->attr.config;
7086 u64 type = event->attr.type;
7089 * Event scheduling is always serialized against hlist allocation
7090 * and release. Which makes the protected version suitable here.
7091 * The context lock guarantees that.
7093 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7094 lockdep_is_held(&event->ctx->lock));
7098 return __find_swevent_head(hlist, type, event_id);
7101 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7103 struct perf_sample_data *data,
7104 struct pt_regs *regs)
7106 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7107 struct perf_event *event;
7108 struct hlist_head *head;
7111 head = find_swevent_head_rcu(swhash, type, event_id);
7115 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7116 if (perf_swevent_match(event, type, event_id, data, regs))
7117 perf_swevent_event(event, nr, data, regs);
7123 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7125 int perf_swevent_get_recursion_context(void)
7127 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7129 return get_recursion_context(swhash->recursion);
7131 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7133 inline void perf_swevent_put_recursion_context(int rctx)
7135 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7137 put_recursion_context(swhash->recursion, rctx);
7140 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7142 struct perf_sample_data data;
7144 if (WARN_ON_ONCE(!regs))
7147 perf_sample_data_init(&data, addr, 0);
7148 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7151 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7155 preempt_disable_notrace();
7156 rctx = perf_swevent_get_recursion_context();
7157 if (unlikely(rctx < 0))
7160 ___perf_sw_event(event_id, nr, regs, addr);
7162 perf_swevent_put_recursion_context(rctx);
7164 preempt_enable_notrace();
7167 static void perf_swevent_read(struct perf_event *event)
7171 static int perf_swevent_add(struct perf_event *event, int flags)
7173 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7174 struct hw_perf_event *hwc = &event->hw;
7175 struct hlist_head *head;
7177 if (is_sampling_event(event)) {
7178 hwc->last_period = hwc->sample_period;
7179 perf_swevent_set_period(event);
7182 hwc->state = !(flags & PERF_EF_START);
7184 head = find_swevent_head(swhash, event);
7185 if (WARN_ON_ONCE(!head))
7188 hlist_add_head_rcu(&event->hlist_entry, head);
7189 perf_event_update_userpage(event);
7194 static void perf_swevent_del(struct perf_event *event, int flags)
7196 hlist_del_rcu(&event->hlist_entry);
7199 static void perf_swevent_start(struct perf_event *event, int flags)
7201 event->hw.state = 0;
7204 static void perf_swevent_stop(struct perf_event *event, int flags)
7206 event->hw.state = PERF_HES_STOPPED;
7209 /* Deref the hlist from the update side */
7210 static inline struct swevent_hlist *
7211 swevent_hlist_deref(struct swevent_htable *swhash)
7213 return rcu_dereference_protected(swhash->swevent_hlist,
7214 lockdep_is_held(&swhash->hlist_mutex));
7217 static void swevent_hlist_release(struct swevent_htable *swhash)
7219 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7224 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7225 kfree_rcu(hlist, rcu_head);
7228 static void swevent_hlist_put_cpu(int cpu)
7230 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7232 mutex_lock(&swhash->hlist_mutex);
7234 if (!--swhash->hlist_refcount)
7235 swevent_hlist_release(swhash);
7237 mutex_unlock(&swhash->hlist_mutex);
7240 static void swevent_hlist_put(void)
7244 for_each_possible_cpu(cpu)
7245 swevent_hlist_put_cpu(cpu);
7248 static int swevent_hlist_get_cpu(int cpu)
7250 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7253 mutex_lock(&swhash->hlist_mutex);
7254 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7255 struct swevent_hlist *hlist;
7257 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7262 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7264 swhash->hlist_refcount++;
7266 mutex_unlock(&swhash->hlist_mutex);
7271 static int swevent_hlist_get(void)
7273 int err, cpu, failed_cpu;
7276 for_each_possible_cpu(cpu) {
7277 err = swevent_hlist_get_cpu(cpu);
7287 for_each_possible_cpu(cpu) {
7288 if (cpu == failed_cpu)
7290 swevent_hlist_put_cpu(cpu);
7297 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7299 static void sw_perf_event_destroy(struct perf_event *event)
7301 u64 event_id = event->attr.config;
7303 WARN_ON(event->parent);
7305 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7306 swevent_hlist_put();
7309 static int perf_swevent_init(struct perf_event *event)
7311 u64 event_id = event->attr.config;
7313 if (event->attr.type != PERF_TYPE_SOFTWARE)
7317 * no branch sampling for software events
7319 if (has_branch_stack(event))
7323 case PERF_COUNT_SW_CPU_CLOCK:
7324 case PERF_COUNT_SW_TASK_CLOCK:
7331 if (event_id >= PERF_COUNT_SW_MAX)
7334 if (!event->parent) {
7337 err = swevent_hlist_get();
7341 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7342 event->destroy = sw_perf_event_destroy;
7348 static struct pmu perf_swevent = {
7349 .task_ctx_nr = perf_sw_context,
7351 .capabilities = PERF_PMU_CAP_NO_NMI,
7353 .event_init = perf_swevent_init,
7354 .add = perf_swevent_add,
7355 .del = perf_swevent_del,
7356 .start = perf_swevent_start,
7357 .stop = perf_swevent_stop,
7358 .read = perf_swevent_read,
7361 #ifdef CONFIG_EVENT_TRACING
7363 static int perf_tp_filter_match(struct perf_event *event,
7364 struct perf_sample_data *data)
7366 void *record = data->raw->data;
7368 /* only top level events have filters set */
7370 event = event->parent;
7372 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7377 static int perf_tp_event_match(struct perf_event *event,
7378 struct perf_sample_data *data,
7379 struct pt_regs *regs)
7381 if (event->hw.state & PERF_HES_STOPPED)
7384 * All tracepoints are from kernel-space.
7386 if (event->attr.exclude_kernel)
7389 if (!perf_tp_filter_match(event, data))
7395 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
7396 struct pt_regs *regs, struct hlist_head *head, int rctx,
7397 struct task_struct *task)
7399 struct perf_sample_data data;
7400 struct perf_event *event;
7402 struct perf_raw_record raw = {
7407 perf_sample_data_init(&data, addr, 0);
7410 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7411 if (perf_tp_event_match(event, &data, regs))
7412 perf_swevent_event(event, count, &data, regs);
7416 * If we got specified a target task, also iterate its context and
7417 * deliver this event there too.
7419 if (task && task != current) {
7420 struct perf_event_context *ctx;
7421 struct trace_entry *entry = record;
7424 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7428 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7429 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7431 if (event->attr.config != entry->type)
7433 if (perf_tp_event_match(event, &data, regs))
7434 perf_swevent_event(event, count, &data, regs);
7440 perf_swevent_put_recursion_context(rctx);
7442 EXPORT_SYMBOL_GPL(perf_tp_event);
7444 static void tp_perf_event_destroy(struct perf_event *event)
7446 perf_trace_destroy(event);
7449 static int perf_tp_event_init(struct perf_event *event)
7453 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7457 * no branch sampling for tracepoint events
7459 if (has_branch_stack(event))
7462 err = perf_trace_init(event);
7466 event->destroy = tp_perf_event_destroy;
7471 static struct pmu perf_tracepoint = {
7472 .task_ctx_nr = perf_sw_context,
7474 .event_init = perf_tp_event_init,
7475 .add = perf_trace_add,
7476 .del = perf_trace_del,
7477 .start = perf_swevent_start,
7478 .stop = perf_swevent_stop,
7479 .read = perf_swevent_read,
7482 static inline void perf_tp_register(void)
7484 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7487 static void perf_event_free_filter(struct perf_event *event)
7489 ftrace_profile_free_filter(event);
7492 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7494 struct bpf_prog *prog;
7496 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7499 if (event->tp_event->prog)
7502 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7503 /* bpf programs can only be attached to u/kprobes */
7506 prog = bpf_prog_get(prog_fd);
7508 return PTR_ERR(prog);
7510 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7511 /* valid fd, but invalid bpf program type */
7516 event->tp_event->prog = prog;
7521 static void perf_event_free_bpf_prog(struct perf_event *event)
7523 struct bpf_prog *prog;
7525 if (!event->tp_event)
7528 prog = event->tp_event->prog;
7530 event->tp_event->prog = NULL;
7537 static inline void perf_tp_register(void)
7541 static void perf_event_free_filter(struct perf_event *event)
7545 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7550 static void perf_event_free_bpf_prog(struct perf_event *event)
7553 #endif /* CONFIG_EVENT_TRACING */
7555 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7556 void perf_bp_event(struct perf_event *bp, void *data)
7558 struct perf_sample_data sample;
7559 struct pt_regs *regs = data;
7561 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7563 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7564 perf_swevent_event(bp, 1, &sample, regs);
7569 * Allocate a new address filter
7571 static struct perf_addr_filter *
7572 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7574 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7575 struct perf_addr_filter *filter;
7577 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
7581 INIT_LIST_HEAD(&filter->entry);
7582 list_add_tail(&filter->entry, filters);
7587 static void free_filters_list(struct list_head *filters)
7589 struct perf_addr_filter *filter, *iter;
7591 list_for_each_entry_safe(filter, iter, filters, entry) {
7593 iput(filter->inode);
7594 list_del(&filter->entry);
7600 * Free existing address filters and optionally install new ones
7602 static void perf_addr_filters_splice(struct perf_event *event,
7603 struct list_head *head)
7605 unsigned long flags;
7608 if (!has_addr_filter(event))
7611 /* don't bother with children, they don't have their own filters */
7615 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
7617 list_splice_init(&event->addr_filters.list, &list);
7619 list_splice(head, &event->addr_filters.list);
7621 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
7623 free_filters_list(&list);
7627 * Scan through mm's vmas and see if one of them matches the
7628 * @filter; if so, adjust filter's address range.
7629 * Called with mm::mmap_sem down for reading.
7631 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
7632 struct mm_struct *mm)
7634 struct vm_area_struct *vma;
7636 for (vma = mm->mmap; vma; vma = vma->vm_next) {
7637 struct file *file = vma->vm_file;
7638 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7639 unsigned long vma_size = vma->vm_end - vma->vm_start;
7644 if (!perf_addr_filter_match(filter, file, off, vma_size))
7647 return vma->vm_start;
7654 * Update event's address range filters based on the
7655 * task's existing mappings, if any.
7657 static void perf_event_addr_filters_apply(struct perf_event *event)
7659 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7660 struct task_struct *task = READ_ONCE(event->ctx->task);
7661 struct perf_addr_filter *filter;
7662 struct mm_struct *mm = NULL;
7663 unsigned int count = 0;
7664 unsigned long flags;
7667 * We may observe TASK_TOMBSTONE, which means that the event tear-down
7668 * will stop on the parent's child_mutex that our caller is also holding
7670 if (task == TASK_TOMBSTONE)
7673 mm = get_task_mm(event->ctx->task);
7677 down_read(&mm->mmap_sem);
7679 raw_spin_lock_irqsave(&ifh->lock, flags);
7680 list_for_each_entry(filter, &ifh->list, entry) {
7681 event->addr_filters_offs[count] = 0;
7683 if (perf_addr_filter_needs_mmap(filter))
7684 event->addr_filters_offs[count] =
7685 perf_addr_filter_apply(filter, mm);
7690 event->addr_filters_gen++;
7691 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7693 up_read(&mm->mmap_sem);
7698 perf_event_restart(event);
7702 * Address range filtering: limiting the data to certain
7703 * instruction address ranges. Filters are ioctl()ed to us from
7704 * userspace as ascii strings.
7706 * Filter string format:
7709 * where ACTION is one of the
7710 * * "filter": limit the trace to this region
7711 * * "start": start tracing from this address
7712 * * "stop": stop tracing at this address/region;
7714 * * for kernel addresses: <start address>[/<size>]
7715 * * for object files: <start address>[/<size>]@</path/to/object/file>
7717 * if <size> is not specified, the range is treated as a single address.
7730 IF_STATE_ACTION = 0,
7735 static const match_table_t if_tokens = {
7736 { IF_ACT_FILTER, "filter" },
7737 { IF_ACT_START, "start" },
7738 { IF_ACT_STOP, "stop" },
7739 { IF_SRC_FILE, "%u/%u@%s" },
7740 { IF_SRC_KERNEL, "%u/%u" },
7741 { IF_SRC_FILEADDR, "%u@%s" },
7742 { IF_SRC_KERNELADDR, "%u" },
7746 * Address filter string parser
7749 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
7750 struct list_head *filters)
7752 struct perf_addr_filter *filter = NULL;
7753 char *start, *orig, *filename = NULL;
7755 substring_t args[MAX_OPT_ARGS];
7756 int state = IF_STATE_ACTION, token;
7757 unsigned int kernel = 0;
7760 orig = fstr = kstrdup(fstr, GFP_KERNEL);
7764 while ((start = strsep(&fstr, " ,\n")) != NULL) {
7770 /* filter definition begins */
7771 if (state == IF_STATE_ACTION) {
7772 filter = perf_addr_filter_new(event, filters);
7777 token = match_token(start, if_tokens, args);
7784 if (state != IF_STATE_ACTION)
7787 state = IF_STATE_SOURCE;
7790 case IF_SRC_KERNELADDR:
7794 case IF_SRC_FILEADDR:
7796 if (state != IF_STATE_SOURCE)
7799 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
7803 ret = kstrtoul(args[0].from, 0, &filter->offset);
7807 if (filter->range) {
7809 ret = kstrtoul(args[1].from, 0, &filter->size);
7814 if (token == IF_SRC_FILE) {
7815 filename = match_strdup(&args[2]);
7822 state = IF_STATE_END;
7830 * Filter definition is fully parsed, validate and install it.
7831 * Make sure that it doesn't contradict itself or the event's
7834 if (state == IF_STATE_END) {
7835 if (kernel && event->attr.exclude_kernel)
7842 /* look up the path and grab its inode */
7843 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
7845 goto fail_free_name;
7847 filter->inode = igrab(d_inode(path.dentry));
7853 if (!filter->inode ||
7854 !S_ISREG(filter->inode->i_mode))
7855 /* free_filters_list() will iput() */
7859 /* ready to consume more filters */
7860 state = IF_STATE_ACTION;
7865 if (state != IF_STATE_ACTION)
7875 free_filters_list(filters);
7882 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
7888 * Since this is called in perf_ioctl() path, we're already holding
7891 lockdep_assert_held(&event->ctx->mutex);
7893 if (WARN_ON_ONCE(event->parent))
7897 * For now, we only support filtering in per-task events; doing so
7898 * for CPU-wide events requires additional context switching trickery,
7899 * since same object code will be mapped at different virtual
7900 * addresses in different processes.
7902 if (!event->ctx->task)
7905 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
7909 ret = event->pmu->addr_filters_validate(&filters);
7911 free_filters_list(&filters);
7915 /* remove existing filters, if any */
7916 perf_addr_filters_splice(event, &filters);
7918 /* install new filters */
7919 perf_event_for_each_child(event, perf_event_addr_filters_apply);
7924 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7929 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
7930 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
7931 !has_addr_filter(event))
7934 filter_str = strndup_user(arg, PAGE_SIZE);
7935 if (IS_ERR(filter_str))
7936 return PTR_ERR(filter_str);
7938 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
7939 event->attr.type == PERF_TYPE_TRACEPOINT)
7940 ret = ftrace_profile_set_filter(event, event->attr.config,
7942 else if (has_addr_filter(event))
7943 ret = perf_event_set_addr_filter(event, filter_str);
7950 * hrtimer based swevent callback
7953 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7955 enum hrtimer_restart ret = HRTIMER_RESTART;
7956 struct perf_sample_data data;
7957 struct pt_regs *regs;
7958 struct perf_event *event;
7961 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7963 if (event->state != PERF_EVENT_STATE_ACTIVE)
7964 return HRTIMER_NORESTART;
7966 event->pmu->read(event);
7968 perf_sample_data_init(&data, 0, event->hw.last_period);
7969 regs = get_irq_regs();
7971 if (regs && !perf_exclude_event(event, regs)) {
7972 if (!(event->attr.exclude_idle && is_idle_task(current)))
7973 if (__perf_event_overflow(event, 1, &data, regs))
7974 ret = HRTIMER_NORESTART;
7977 period = max_t(u64, 10000, event->hw.sample_period);
7978 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7983 static void perf_swevent_start_hrtimer(struct perf_event *event)
7985 struct hw_perf_event *hwc = &event->hw;
7988 if (!is_sampling_event(event))
7991 period = local64_read(&hwc->period_left);
7996 local64_set(&hwc->period_left, 0);
7998 period = max_t(u64, 10000, hwc->sample_period);
8000 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8001 HRTIMER_MODE_REL_PINNED);
8004 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8006 struct hw_perf_event *hwc = &event->hw;
8008 if (is_sampling_event(event)) {
8009 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8010 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8012 hrtimer_cancel(&hwc->hrtimer);
8016 static void perf_swevent_init_hrtimer(struct perf_event *event)
8018 struct hw_perf_event *hwc = &event->hw;
8020 if (!is_sampling_event(event))
8023 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8024 hwc->hrtimer.function = perf_swevent_hrtimer;
8027 * Since hrtimers have a fixed rate, we can do a static freq->period
8028 * mapping and avoid the whole period adjust feedback stuff.
8030 if (event->attr.freq) {
8031 long freq = event->attr.sample_freq;
8033 event->attr.sample_period = NSEC_PER_SEC / freq;
8034 hwc->sample_period = event->attr.sample_period;
8035 local64_set(&hwc->period_left, hwc->sample_period);
8036 hwc->last_period = hwc->sample_period;
8037 event->attr.freq = 0;
8042 * Software event: cpu wall time clock
8045 static void cpu_clock_event_update(struct perf_event *event)
8050 now = local_clock();
8051 prev = local64_xchg(&event->hw.prev_count, now);
8052 local64_add(now - prev, &event->count);
8055 static void cpu_clock_event_start(struct perf_event *event, int flags)
8057 local64_set(&event->hw.prev_count, local_clock());
8058 perf_swevent_start_hrtimer(event);
8061 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8063 perf_swevent_cancel_hrtimer(event);
8064 cpu_clock_event_update(event);
8067 static int cpu_clock_event_add(struct perf_event *event, int flags)
8069 if (flags & PERF_EF_START)
8070 cpu_clock_event_start(event, flags);
8071 perf_event_update_userpage(event);
8076 static void cpu_clock_event_del(struct perf_event *event, int flags)
8078 cpu_clock_event_stop(event, flags);
8081 static void cpu_clock_event_read(struct perf_event *event)
8083 cpu_clock_event_update(event);
8086 static int cpu_clock_event_init(struct perf_event *event)
8088 if (event->attr.type != PERF_TYPE_SOFTWARE)
8091 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8095 * no branch sampling for software events
8097 if (has_branch_stack(event))
8100 perf_swevent_init_hrtimer(event);
8105 static struct pmu perf_cpu_clock = {
8106 .task_ctx_nr = perf_sw_context,
8108 .capabilities = PERF_PMU_CAP_NO_NMI,
8110 .event_init = cpu_clock_event_init,
8111 .add = cpu_clock_event_add,
8112 .del = cpu_clock_event_del,
8113 .start = cpu_clock_event_start,
8114 .stop = cpu_clock_event_stop,
8115 .read = cpu_clock_event_read,
8119 * Software event: task time clock
8122 static void task_clock_event_update(struct perf_event *event, u64 now)
8127 prev = local64_xchg(&event->hw.prev_count, now);
8129 local64_add(delta, &event->count);
8132 static void task_clock_event_start(struct perf_event *event, int flags)
8134 local64_set(&event->hw.prev_count, event->ctx->time);
8135 perf_swevent_start_hrtimer(event);
8138 static void task_clock_event_stop(struct perf_event *event, int flags)
8140 perf_swevent_cancel_hrtimer(event);
8141 task_clock_event_update(event, event->ctx->time);
8144 static int task_clock_event_add(struct perf_event *event, int flags)
8146 if (flags & PERF_EF_START)
8147 task_clock_event_start(event, flags);
8148 perf_event_update_userpage(event);
8153 static void task_clock_event_del(struct perf_event *event, int flags)
8155 task_clock_event_stop(event, PERF_EF_UPDATE);
8158 static void task_clock_event_read(struct perf_event *event)
8160 u64 now = perf_clock();
8161 u64 delta = now - event->ctx->timestamp;
8162 u64 time = event->ctx->time + delta;
8164 task_clock_event_update(event, time);
8167 static int task_clock_event_init(struct perf_event *event)
8169 if (event->attr.type != PERF_TYPE_SOFTWARE)
8172 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8176 * no branch sampling for software events
8178 if (has_branch_stack(event))
8181 perf_swevent_init_hrtimer(event);
8186 static struct pmu perf_task_clock = {
8187 .task_ctx_nr = perf_sw_context,
8189 .capabilities = PERF_PMU_CAP_NO_NMI,
8191 .event_init = task_clock_event_init,
8192 .add = task_clock_event_add,
8193 .del = task_clock_event_del,
8194 .start = task_clock_event_start,
8195 .stop = task_clock_event_stop,
8196 .read = task_clock_event_read,
8199 static void perf_pmu_nop_void(struct pmu *pmu)
8203 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8207 static int perf_pmu_nop_int(struct pmu *pmu)
8212 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8214 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8216 __this_cpu_write(nop_txn_flags, flags);
8218 if (flags & ~PERF_PMU_TXN_ADD)
8221 perf_pmu_disable(pmu);
8224 static int perf_pmu_commit_txn(struct pmu *pmu)
8226 unsigned int flags = __this_cpu_read(nop_txn_flags);
8228 __this_cpu_write(nop_txn_flags, 0);
8230 if (flags & ~PERF_PMU_TXN_ADD)
8233 perf_pmu_enable(pmu);
8237 static void perf_pmu_cancel_txn(struct pmu *pmu)
8239 unsigned int flags = __this_cpu_read(nop_txn_flags);
8241 __this_cpu_write(nop_txn_flags, 0);
8243 if (flags & ~PERF_PMU_TXN_ADD)
8246 perf_pmu_enable(pmu);
8249 static int perf_event_idx_default(struct perf_event *event)
8255 * Ensures all contexts with the same task_ctx_nr have the same
8256 * pmu_cpu_context too.
8258 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8265 list_for_each_entry(pmu, &pmus, entry) {
8266 if (pmu->task_ctx_nr == ctxn)
8267 return pmu->pmu_cpu_context;
8273 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8277 for_each_possible_cpu(cpu) {
8278 struct perf_cpu_context *cpuctx;
8280 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8282 if (cpuctx->unique_pmu == old_pmu)
8283 cpuctx->unique_pmu = pmu;
8287 static void free_pmu_context(struct pmu *pmu)
8291 mutex_lock(&pmus_lock);
8293 * Like a real lame refcount.
8295 list_for_each_entry(i, &pmus, entry) {
8296 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
8297 update_pmu_context(i, pmu);
8302 free_percpu(pmu->pmu_cpu_context);
8304 mutex_unlock(&pmus_lock);
8308 * Let userspace know that this PMU supports address range filtering:
8310 static ssize_t nr_addr_filters_show(struct device *dev,
8311 struct device_attribute *attr,
8314 struct pmu *pmu = dev_get_drvdata(dev);
8316 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8318 DEVICE_ATTR_RO(nr_addr_filters);
8320 static struct idr pmu_idr;
8323 type_show(struct device *dev, struct device_attribute *attr, char *page)
8325 struct pmu *pmu = dev_get_drvdata(dev);
8327 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8329 static DEVICE_ATTR_RO(type);
8332 perf_event_mux_interval_ms_show(struct device *dev,
8333 struct device_attribute *attr,
8336 struct pmu *pmu = dev_get_drvdata(dev);
8338 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8341 static DEFINE_MUTEX(mux_interval_mutex);
8344 perf_event_mux_interval_ms_store(struct device *dev,
8345 struct device_attribute *attr,
8346 const char *buf, size_t count)
8348 struct pmu *pmu = dev_get_drvdata(dev);
8349 int timer, cpu, ret;
8351 ret = kstrtoint(buf, 0, &timer);
8358 /* same value, noting to do */
8359 if (timer == pmu->hrtimer_interval_ms)
8362 mutex_lock(&mux_interval_mutex);
8363 pmu->hrtimer_interval_ms = timer;
8365 /* update all cpuctx for this PMU */
8367 for_each_online_cpu(cpu) {
8368 struct perf_cpu_context *cpuctx;
8369 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8370 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8372 cpu_function_call(cpu,
8373 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8376 mutex_unlock(&mux_interval_mutex);
8380 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8382 static struct attribute *pmu_dev_attrs[] = {
8383 &dev_attr_type.attr,
8384 &dev_attr_perf_event_mux_interval_ms.attr,
8387 ATTRIBUTE_GROUPS(pmu_dev);
8389 static int pmu_bus_running;
8390 static struct bus_type pmu_bus = {
8391 .name = "event_source",
8392 .dev_groups = pmu_dev_groups,
8395 static void pmu_dev_release(struct device *dev)
8400 static int pmu_dev_alloc(struct pmu *pmu)
8404 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8408 pmu->dev->groups = pmu->attr_groups;
8409 device_initialize(pmu->dev);
8410 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8414 dev_set_drvdata(pmu->dev, pmu);
8415 pmu->dev->bus = &pmu_bus;
8416 pmu->dev->release = pmu_dev_release;
8417 ret = device_add(pmu->dev);
8421 /* For PMUs with address filters, throw in an extra attribute: */
8422 if (pmu->nr_addr_filters)
8423 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8432 device_del(pmu->dev);
8435 put_device(pmu->dev);
8439 static struct lock_class_key cpuctx_mutex;
8440 static struct lock_class_key cpuctx_lock;
8442 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8446 mutex_lock(&pmus_lock);
8448 pmu->pmu_disable_count = alloc_percpu(int);
8449 if (!pmu->pmu_disable_count)
8458 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8466 if (pmu_bus_running) {
8467 ret = pmu_dev_alloc(pmu);
8473 if (pmu->task_ctx_nr == perf_hw_context) {
8474 static int hw_context_taken = 0;
8477 * Other than systems with heterogeneous CPUs, it never makes
8478 * sense for two PMUs to share perf_hw_context. PMUs which are
8479 * uncore must use perf_invalid_context.
8481 if (WARN_ON_ONCE(hw_context_taken &&
8482 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8483 pmu->task_ctx_nr = perf_invalid_context;
8485 hw_context_taken = 1;
8488 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8489 if (pmu->pmu_cpu_context)
8490 goto got_cpu_context;
8493 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8494 if (!pmu->pmu_cpu_context)
8497 for_each_possible_cpu(cpu) {
8498 struct perf_cpu_context *cpuctx;
8500 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8501 __perf_event_init_context(&cpuctx->ctx);
8502 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8503 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8504 cpuctx->ctx.pmu = pmu;
8506 __perf_mux_hrtimer_init(cpuctx, cpu);
8508 cpuctx->unique_pmu = pmu;
8512 if (!pmu->start_txn) {
8513 if (pmu->pmu_enable) {
8515 * If we have pmu_enable/pmu_disable calls, install
8516 * transaction stubs that use that to try and batch
8517 * hardware accesses.
8519 pmu->start_txn = perf_pmu_start_txn;
8520 pmu->commit_txn = perf_pmu_commit_txn;
8521 pmu->cancel_txn = perf_pmu_cancel_txn;
8523 pmu->start_txn = perf_pmu_nop_txn;
8524 pmu->commit_txn = perf_pmu_nop_int;
8525 pmu->cancel_txn = perf_pmu_nop_void;
8529 if (!pmu->pmu_enable) {
8530 pmu->pmu_enable = perf_pmu_nop_void;
8531 pmu->pmu_disable = perf_pmu_nop_void;
8534 if (!pmu->event_idx)
8535 pmu->event_idx = perf_event_idx_default;
8537 list_add_rcu(&pmu->entry, &pmus);
8538 atomic_set(&pmu->exclusive_cnt, 0);
8541 mutex_unlock(&pmus_lock);
8546 device_del(pmu->dev);
8547 put_device(pmu->dev);
8550 if (pmu->type >= PERF_TYPE_MAX)
8551 idr_remove(&pmu_idr, pmu->type);
8554 free_percpu(pmu->pmu_disable_count);
8557 EXPORT_SYMBOL_GPL(perf_pmu_register);
8559 void perf_pmu_unregister(struct pmu *pmu)
8561 mutex_lock(&pmus_lock);
8562 list_del_rcu(&pmu->entry);
8563 mutex_unlock(&pmus_lock);
8566 * We dereference the pmu list under both SRCU and regular RCU, so
8567 * synchronize against both of those.
8569 synchronize_srcu(&pmus_srcu);
8572 free_percpu(pmu->pmu_disable_count);
8573 if (pmu->type >= PERF_TYPE_MAX)
8574 idr_remove(&pmu_idr, pmu->type);
8575 if (pmu->nr_addr_filters)
8576 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8577 device_del(pmu->dev);
8578 put_device(pmu->dev);
8579 free_pmu_context(pmu);
8581 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8583 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8585 struct perf_event_context *ctx = NULL;
8588 if (!try_module_get(pmu->module))
8591 if (event->group_leader != event) {
8593 * This ctx->mutex can nest when we're called through
8594 * inheritance. See the perf_event_ctx_lock_nested() comment.
8596 ctx = perf_event_ctx_lock_nested(event->group_leader,
8597 SINGLE_DEPTH_NESTING);
8602 ret = pmu->event_init(event);
8605 perf_event_ctx_unlock(event->group_leader, ctx);
8608 module_put(pmu->module);
8613 static struct pmu *perf_init_event(struct perf_event *event)
8615 struct pmu *pmu = NULL;
8619 idx = srcu_read_lock(&pmus_srcu);
8622 pmu = idr_find(&pmu_idr, event->attr.type);
8625 ret = perf_try_init_event(pmu, event);
8631 list_for_each_entry_rcu(pmu, &pmus, entry) {
8632 ret = perf_try_init_event(pmu, event);
8636 if (ret != -ENOENT) {
8641 pmu = ERR_PTR(-ENOENT);
8643 srcu_read_unlock(&pmus_srcu, idx);
8648 static void attach_sb_event(struct perf_event *event)
8650 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
8652 raw_spin_lock(&pel->lock);
8653 list_add_rcu(&event->sb_list, &pel->list);
8654 raw_spin_unlock(&pel->lock);
8657 static void account_pmu_sb_event(struct perf_event *event)
8659 struct perf_event_attr *attr = &event->attr;
8664 if (event->attach_state & PERF_ATTACH_TASK)
8667 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
8668 attr->comm || attr->comm_exec ||
8670 attr->context_switch)
8671 attach_sb_event(event);
8674 static void account_event_cpu(struct perf_event *event, int cpu)
8679 if (is_cgroup_event(event))
8680 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
8683 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
8684 static void account_freq_event_nohz(void)
8686 #ifdef CONFIG_NO_HZ_FULL
8687 /* Lock so we don't race with concurrent unaccount */
8688 spin_lock(&nr_freq_lock);
8689 if (atomic_inc_return(&nr_freq_events) == 1)
8690 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
8691 spin_unlock(&nr_freq_lock);
8695 static void account_freq_event(void)
8697 if (tick_nohz_full_enabled())
8698 account_freq_event_nohz();
8700 atomic_inc(&nr_freq_events);
8704 static void account_event(struct perf_event *event)
8711 if (event->attach_state & PERF_ATTACH_TASK)
8713 if (event->attr.mmap || event->attr.mmap_data)
8714 atomic_inc(&nr_mmap_events);
8715 if (event->attr.comm)
8716 atomic_inc(&nr_comm_events);
8717 if (event->attr.task)
8718 atomic_inc(&nr_task_events);
8719 if (event->attr.freq)
8720 account_freq_event();
8721 if (event->attr.context_switch) {
8722 atomic_inc(&nr_switch_events);
8725 if (has_branch_stack(event))
8727 if (is_cgroup_event(event))
8731 if (atomic_inc_not_zero(&perf_sched_count))
8734 mutex_lock(&perf_sched_mutex);
8735 if (!atomic_read(&perf_sched_count)) {
8736 static_branch_enable(&perf_sched_events);
8738 * Guarantee that all CPUs observe they key change and
8739 * call the perf scheduling hooks before proceeding to
8740 * install events that need them.
8742 synchronize_sched();
8745 * Now that we have waited for the sync_sched(), allow further
8746 * increments to by-pass the mutex.
8748 atomic_inc(&perf_sched_count);
8749 mutex_unlock(&perf_sched_mutex);
8753 account_event_cpu(event, event->cpu);
8755 account_pmu_sb_event(event);
8759 * Allocate and initialize a event structure
8761 static struct perf_event *
8762 perf_event_alloc(struct perf_event_attr *attr, int cpu,
8763 struct task_struct *task,
8764 struct perf_event *group_leader,
8765 struct perf_event *parent_event,
8766 perf_overflow_handler_t overflow_handler,
8767 void *context, int cgroup_fd)
8770 struct perf_event *event;
8771 struct hw_perf_event *hwc;
8774 if ((unsigned)cpu >= nr_cpu_ids) {
8775 if (!task || cpu != -1)
8776 return ERR_PTR(-EINVAL);
8779 event = kzalloc(sizeof(*event), GFP_KERNEL);
8781 return ERR_PTR(-ENOMEM);
8784 * Single events are their own group leaders, with an
8785 * empty sibling list:
8788 group_leader = event;
8790 mutex_init(&event->child_mutex);
8791 INIT_LIST_HEAD(&event->child_list);
8793 INIT_LIST_HEAD(&event->group_entry);
8794 INIT_LIST_HEAD(&event->event_entry);
8795 INIT_LIST_HEAD(&event->sibling_list);
8796 INIT_LIST_HEAD(&event->rb_entry);
8797 INIT_LIST_HEAD(&event->active_entry);
8798 INIT_LIST_HEAD(&event->addr_filters.list);
8799 INIT_HLIST_NODE(&event->hlist_entry);
8802 init_waitqueue_head(&event->waitq);
8803 init_irq_work(&event->pending, perf_pending_event);
8805 mutex_init(&event->mmap_mutex);
8806 raw_spin_lock_init(&event->addr_filters.lock);
8808 atomic_long_set(&event->refcount, 1);
8810 event->attr = *attr;
8811 event->group_leader = group_leader;
8815 event->parent = parent_event;
8817 event->ns = get_pid_ns(task_active_pid_ns(current));
8818 event->id = atomic64_inc_return(&perf_event_id);
8820 event->state = PERF_EVENT_STATE_INACTIVE;
8823 event->attach_state = PERF_ATTACH_TASK;
8825 * XXX pmu::event_init needs to know what task to account to
8826 * and we cannot use the ctx information because we need the
8827 * pmu before we get a ctx.
8829 event->hw.target = task;
8832 event->clock = &local_clock;
8834 event->clock = parent_event->clock;
8836 if (!overflow_handler && parent_event) {
8837 overflow_handler = parent_event->overflow_handler;
8838 context = parent_event->overflow_handler_context;
8841 if (overflow_handler) {
8842 event->overflow_handler = overflow_handler;
8843 event->overflow_handler_context = context;
8844 } else if (is_write_backward(event)){
8845 event->overflow_handler = perf_event_output_backward;
8846 event->overflow_handler_context = NULL;
8848 event->overflow_handler = perf_event_output_forward;
8849 event->overflow_handler_context = NULL;
8852 perf_event__state_init(event);
8857 hwc->sample_period = attr->sample_period;
8858 if (attr->freq && attr->sample_freq)
8859 hwc->sample_period = 1;
8860 hwc->last_period = hwc->sample_period;
8862 local64_set(&hwc->period_left, hwc->sample_period);
8865 * we currently do not support PERF_FORMAT_GROUP on inherited events
8867 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8870 if (!has_branch_stack(event))
8871 event->attr.branch_sample_type = 0;
8873 if (cgroup_fd != -1) {
8874 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8879 pmu = perf_init_event(event);
8882 else if (IS_ERR(pmu)) {
8887 err = exclusive_event_init(event);
8891 if (has_addr_filter(event)) {
8892 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
8893 sizeof(unsigned long),
8895 if (!event->addr_filters_offs)
8898 /* force hw sync on the address filters */
8899 event->addr_filters_gen = 1;
8902 if (!event->parent) {
8903 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8904 err = get_callchain_buffers(attr->sample_max_stack);
8906 goto err_addr_filters;
8910 /* symmetric to unaccount_event() in _free_event() */
8911 account_event(event);
8916 kfree(event->addr_filters_offs);
8919 exclusive_event_destroy(event);
8923 event->destroy(event);
8924 module_put(pmu->module);
8926 if (is_cgroup_event(event))
8927 perf_detach_cgroup(event);
8929 put_pid_ns(event->ns);
8932 return ERR_PTR(err);
8935 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8936 struct perf_event_attr *attr)
8941 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8945 * zero the full structure, so that a short copy will be nice.
8947 memset(attr, 0, sizeof(*attr));
8949 ret = get_user(size, &uattr->size);
8953 if (size > PAGE_SIZE) /* silly large */
8956 if (!size) /* abi compat */
8957 size = PERF_ATTR_SIZE_VER0;
8959 if (size < PERF_ATTR_SIZE_VER0)
8963 * If we're handed a bigger struct than we know of,
8964 * ensure all the unknown bits are 0 - i.e. new
8965 * user-space does not rely on any kernel feature
8966 * extensions we dont know about yet.
8968 if (size > sizeof(*attr)) {
8969 unsigned char __user *addr;
8970 unsigned char __user *end;
8973 addr = (void __user *)uattr + sizeof(*attr);
8974 end = (void __user *)uattr + size;
8976 for (; addr < end; addr++) {
8977 ret = get_user(val, addr);
8983 size = sizeof(*attr);
8986 ret = copy_from_user(attr, uattr, size);
8990 if (attr->__reserved_1)
8993 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8996 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8999 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9000 u64 mask = attr->branch_sample_type;
9002 /* only using defined bits */
9003 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9006 /* at least one branch bit must be set */
9007 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9010 /* propagate priv level, when not set for branch */
9011 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9013 /* exclude_kernel checked on syscall entry */
9014 if (!attr->exclude_kernel)
9015 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9017 if (!attr->exclude_user)
9018 mask |= PERF_SAMPLE_BRANCH_USER;
9020 if (!attr->exclude_hv)
9021 mask |= PERF_SAMPLE_BRANCH_HV;
9023 * adjust user setting (for HW filter setup)
9025 attr->branch_sample_type = mask;
9027 /* privileged levels capture (kernel, hv): check permissions */
9028 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9029 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9033 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9034 ret = perf_reg_validate(attr->sample_regs_user);
9039 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9040 if (!arch_perf_have_user_stack_dump())
9044 * We have __u32 type for the size, but so far
9045 * we can only use __u16 as maximum due to the
9046 * __u16 sample size limit.
9048 if (attr->sample_stack_user >= USHRT_MAX)
9050 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9054 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9055 ret = perf_reg_validate(attr->sample_regs_intr);
9060 put_user(sizeof(*attr), &uattr->size);
9066 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9068 struct ring_buffer *rb = NULL;
9074 /* don't allow circular references */
9075 if (event == output_event)
9079 * Don't allow cross-cpu buffers
9081 if (output_event->cpu != event->cpu)
9085 * If its not a per-cpu rb, it must be the same task.
9087 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9091 * Mixing clocks in the same buffer is trouble you don't need.
9093 if (output_event->clock != event->clock)
9097 * Either writing ring buffer from beginning or from end.
9098 * Mixing is not allowed.
9100 if (is_write_backward(output_event) != is_write_backward(event))
9104 * If both events generate aux data, they must be on the same PMU
9106 if (has_aux(event) && has_aux(output_event) &&
9107 event->pmu != output_event->pmu)
9111 mutex_lock(&event->mmap_mutex);
9112 /* Can't redirect output if we've got an active mmap() */
9113 if (atomic_read(&event->mmap_count))
9117 /* get the rb we want to redirect to */
9118 rb = ring_buffer_get(output_event);
9123 ring_buffer_attach(event, rb);
9127 mutex_unlock(&event->mmap_mutex);
9133 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9139 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9142 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9144 bool nmi_safe = false;
9147 case CLOCK_MONOTONIC:
9148 event->clock = &ktime_get_mono_fast_ns;
9152 case CLOCK_MONOTONIC_RAW:
9153 event->clock = &ktime_get_raw_fast_ns;
9157 case CLOCK_REALTIME:
9158 event->clock = &ktime_get_real_ns;
9161 case CLOCK_BOOTTIME:
9162 event->clock = &ktime_get_boot_ns;
9166 event->clock = &ktime_get_tai_ns;
9173 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9180 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9182 * @attr_uptr: event_id type attributes for monitoring/sampling
9185 * @group_fd: group leader event fd
9187 SYSCALL_DEFINE5(perf_event_open,
9188 struct perf_event_attr __user *, attr_uptr,
9189 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9191 struct perf_event *group_leader = NULL, *output_event = NULL;
9192 struct perf_event *event, *sibling;
9193 struct perf_event_attr attr;
9194 struct perf_event_context *ctx, *uninitialized_var(gctx);
9195 struct file *event_file = NULL;
9196 struct fd group = {NULL, 0};
9197 struct task_struct *task = NULL;
9202 int f_flags = O_RDWR;
9205 /* for future expandability... */
9206 if (flags & ~PERF_FLAG_ALL)
9209 err = perf_copy_attr(attr_uptr, &attr);
9213 if (!attr.exclude_kernel) {
9214 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9219 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9222 if (attr.sample_period & (1ULL << 63))
9226 if (!attr.sample_max_stack)
9227 attr.sample_max_stack = sysctl_perf_event_max_stack;
9230 * In cgroup mode, the pid argument is used to pass the fd
9231 * opened to the cgroup directory in cgroupfs. The cpu argument
9232 * designates the cpu on which to monitor threads from that
9235 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9238 if (flags & PERF_FLAG_FD_CLOEXEC)
9239 f_flags |= O_CLOEXEC;
9241 event_fd = get_unused_fd_flags(f_flags);
9245 if (group_fd != -1) {
9246 err = perf_fget_light(group_fd, &group);
9249 group_leader = group.file->private_data;
9250 if (flags & PERF_FLAG_FD_OUTPUT)
9251 output_event = group_leader;
9252 if (flags & PERF_FLAG_FD_NO_GROUP)
9253 group_leader = NULL;
9256 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9257 task = find_lively_task_by_vpid(pid);
9259 err = PTR_ERR(task);
9264 if (task && group_leader &&
9265 group_leader->attr.inherit != attr.inherit) {
9273 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9278 * Reuse ptrace permission checks for now.
9280 * We must hold cred_guard_mutex across this and any potential
9281 * perf_install_in_context() call for this new event to
9282 * serialize against exec() altering our credentials (and the
9283 * perf_event_exit_task() that could imply).
9286 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9290 if (flags & PERF_FLAG_PID_CGROUP)
9293 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9294 NULL, NULL, cgroup_fd);
9295 if (IS_ERR(event)) {
9296 err = PTR_ERR(event);
9300 if (is_sampling_event(event)) {
9301 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9308 * Special case software events and allow them to be part of
9309 * any hardware group.
9313 if (attr.use_clockid) {
9314 err = perf_event_set_clock(event, attr.clockid);
9320 (is_software_event(event) != is_software_event(group_leader))) {
9321 if (is_software_event(event)) {
9323 * If event and group_leader are not both a software
9324 * event, and event is, then group leader is not.
9326 * Allow the addition of software events to !software
9327 * groups, this is safe because software events never
9330 pmu = group_leader->pmu;
9331 } else if (is_software_event(group_leader) &&
9332 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
9334 * In case the group is a pure software group, and we
9335 * try to add a hardware event, move the whole group to
9336 * the hardware context.
9343 * Get the target context (task or percpu):
9345 ctx = find_get_context(pmu, task, event);
9351 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9357 * Look up the group leader (we will attach this event to it):
9363 * Do not allow a recursive hierarchy (this new sibling
9364 * becoming part of another group-sibling):
9366 if (group_leader->group_leader != group_leader)
9369 /* All events in a group should have the same clock */
9370 if (group_leader->clock != event->clock)
9374 * Do not allow to attach to a group in a different
9375 * task or CPU context:
9379 * Make sure we're both on the same task, or both
9382 if (group_leader->ctx->task != ctx->task)
9386 * Make sure we're both events for the same CPU;
9387 * grouping events for different CPUs is broken; since
9388 * you can never concurrently schedule them anyhow.
9390 if (group_leader->cpu != event->cpu)
9393 if (group_leader->ctx != ctx)
9398 * Only a group leader can be exclusive or pinned
9400 if (attr.exclusive || attr.pinned)
9405 err = perf_event_set_output(event, output_event);
9410 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9412 if (IS_ERR(event_file)) {
9413 err = PTR_ERR(event_file);
9419 gctx = group_leader->ctx;
9420 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9421 if (gctx->task == TASK_TOMBSTONE) {
9426 mutex_lock(&ctx->mutex);
9429 if (ctx->task == TASK_TOMBSTONE) {
9434 if (!perf_event_validate_size(event)) {
9440 * Must be under the same ctx::mutex as perf_install_in_context(),
9441 * because we need to serialize with concurrent event creation.
9443 if (!exclusive_event_installable(event, ctx)) {
9444 /* exclusive and group stuff are assumed mutually exclusive */
9445 WARN_ON_ONCE(move_group);
9451 WARN_ON_ONCE(ctx->parent_ctx);
9454 * This is the point on no return; we cannot fail hereafter. This is
9455 * where we start modifying current state.
9460 * See perf_event_ctx_lock() for comments on the details
9461 * of swizzling perf_event::ctx.
9463 perf_remove_from_context(group_leader, 0);
9465 list_for_each_entry(sibling, &group_leader->sibling_list,
9467 perf_remove_from_context(sibling, 0);
9472 * Wait for everybody to stop referencing the events through
9473 * the old lists, before installing it on new lists.
9478 * Install the group siblings before the group leader.
9480 * Because a group leader will try and install the entire group
9481 * (through the sibling list, which is still in-tact), we can
9482 * end up with siblings installed in the wrong context.
9484 * By installing siblings first we NO-OP because they're not
9485 * reachable through the group lists.
9487 list_for_each_entry(sibling, &group_leader->sibling_list,
9489 perf_event__state_init(sibling);
9490 perf_install_in_context(ctx, sibling, sibling->cpu);
9495 * Removing from the context ends up with disabled
9496 * event. What we want here is event in the initial
9497 * startup state, ready to be add into new context.
9499 perf_event__state_init(group_leader);
9500 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9504 * Now that all events are installed in @ctx, nothing
9505 * references @gctx anymore, so drop the last reference we have
9512 * Precalculate sample_data sizes; do while holding ctx::mutex such
9513 * that we're serialized against further additions and before
9514 * perf_install_in_context() which is the point the event is active and
9515 * can use these values.
9517 perf_event__header_size(event);
9518 perf_event__id_header_size(event);
9520 event->owner = current;
9522 perf_install_in_context(ctx, event, event->cpu);
9523 perf_unpin_context(ctx);
9526 mutex_unlock(&gctx->mutex);
9527 mutex_unlock(&ctx->mutex);
9530 mutex_unlock(&task->signal->cred_guard_mutex);
9531 put_task_struct(task);
9536 mutex_lock(¤t->perf_event_mutex);
9537 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
9538 mutex_unlock(¤t->perf_event_mutex);
9541 * Drop the reference on the group_event after placing the
9542 * new event on the sibling_list. This ensures destruction
9543 * of the group leader will find the pointer to itself in
9544 * perf_group_detach().
9547 fd_install(event_fd, event_file);
9552 mutex_unlock(&gctx->mutex);
9553 mutex_unlock(&ctx->mutex);
9557 perf_unpin_context(ctx);
9561 * If event_file is set, the fput() above will have called ->release()
9562 * and that will take care of freeing the event.
9568 mutex_unlock(&task->signal->cred_guard_mutex);
9573 put_task_struct(task);
9577 put_unused_fd(event_fd);
9582 * perf_event_create_kernel_counter
9584 * @attr: attributes of the counter to create
9585 * @cpu: cpu in which the counter is bound
9586 * @task: task to profile (NULL for percpu)
9589 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
9590 struct task_struct *task,
9591 perf_overflow_handler_t overflow_handler,
9594 struct perf_event_context *ctx;
9595 struct perf_event *event;
9599 * Get the target context (task or percpu):
9602 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9603 overflow_handler, context, -1);
9604 if (IS_ERR(event)) {
9605 err = PTR_ERR(event);
9609 /* Mark owner so we could distinguish it from user events. */
9610 event->owner = TASK_TOMBSTONE;
9612 ctx = find_get_context(event->pmu, task, event);
9618 WARN_ON_ONCE(ctx->parent_ctx);
9619 mutex_lock(&ctx->mutex);
9620 if (ctx->task == TASK_TOMBSTONE) {
9625 if (!exclusive_event_installable(event, ctx)) {
9630 perf_install_in_context(ctx, event, cpu);
9631 perf_unpin_context(ctx);
9632 mutex_unlock(&ctx->mutex);
9637 mutex_unlock(&ctx->mutex);
9638 perf_unpin_context(ctx);
9643 return ERR_PTR(err);
9645 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9647 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
9649 struct perf_event_context *src_ctx;
9650 struct perf_event_context *dst_ctx;
9651 struct perf_event *event, *tmp;
9654 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
9655 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
9658 * See perf_event_ctx_lock() for comments on the details
9659 * of swizzling perf_event::ctx.
9661 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9662 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
9664 perf_remove_from_context(event, 0);
9665 unaccount_event_cpu(event, src_cpu);
9667 list_add(&event->migrate_entry, &events);
9671 * Wait for the events to quiesce before re-instating them.
9676 * Re-instate events in 2 passes.
9678 * Skip over group leaders and only install siblings on this first
9679 * pass, siblings will not get enabled without a leader, however a
9680 * leader will enable its siblings, even if those are still on the old
9683 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9684 if (event->group_leader == event)
9687 list_del(&event->migrate_entry);
9688 if (event->state >= PERF_EVENT_STATE_OFF)
9689 event->state = PERF_EVENT_STATE_INACTIVE;
9690 account_event_cpu(event, dst_cpu);
9691 perf_install_in_context(dst_ctx, event, dst_cpu);
9696 * Once all the siblings are setup properly, install the group leaders
9699 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9700 list_del(&event->migrate_entry);
9701 if (event->state >= PERF_EVENT_STATE_OFF)
9702 event->state = PERF_EVENT_STATE_INACTIVE;
9703 account_event_cpu(event, dst_cpu);
9704 perf_install_in_context(dst_ctx, event, dst_cpu);
9707 mutex_unlock(&dst_ctx->mutex);
9708 mutex_unlock(&src_ctx->mutex);
9710 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
9712 static void sync_child_event(struct perf_event *child_event,
9713 struct task_struct *child)
9715 struct perf_event *parent_event = child_event->parent;
9718 if (child_event->attr.inherit_stat)
9719 perf_event_read_event(child_event, child);
9721 child_val = perf_event_count(child_event);
9724 * Add back the child's count to the parent's count:
9726 atomic64_add(child_val, &parent_event->child_count);
9727 atomic64_add(child_event->total_time_enabled,
9728 &parent_event->child_total_time_enabled);
9729 atomic64_add(child_event->total_time_running,
9730 &parent_event->child_total_time_running);
9734 perf_event_exit_event(struct perf_event *child_event,
9735 struct perf_event_context *child_ctx,
9736 struct task_struct *child)
9738 struct perf_event *parent_event = child_event->parent;
9741 * Do not destroy the 'original' grouping; because of the context
9742 * switch optimization the original events could've ended up in a
9743 * random child task.
9745 * If we were to destroy the original group, all group related
9746 * operations would cease to function properly after this random
9749 * Do destroy all inherited groups, we don't care about those
9750 * and being thorough is better.
9752 raw_spin_lock_irq(&child_ctx->lock);
9753 WARN_ON_ONCE(child_ctx->is_active);
9756 perf_group_detach(child_event);
9757 list_del_event(child_event, child_ctx);
9758 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9759 raw_spin_unlock_irq(&child_ctx->lock);
9762 * Parent events are governed by their filedesc, retain them.
9764 if (!parent_event) {
9765 perf_event_wakeup(child_event);
9769 * Child events can be cleaned up.
9772 sync_child_event(child_event, child);
9775 * Remove this event from the parent's list
9777 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9778 mutex_lock(&parent_event->child_mutex);
9779 list_del_init(&child_event->child_list);
9780 mutex_unlock(&parent_event->child_mutex);
9783 * Kick perf_poll() for is_event_hup().
9785 perf_event_wakeup(parent_event);
9786 free_event(child_event);
9787 put_event(parent_event);
9790 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9792 struct perf_event_context *child_ctx, *clone_ctx = NULL;
9793 struct perf_event *child_event, *next;
9795 WARN_ON_ONCE(child != current);
9797 child_ctx = perf_pin_task_context(child, ctxn);
9802 * In order to reduce the amount of tricky in ctx tear-down, we hold
9803 * ctx::mutex over the entire thing. This serializes against almost
9804 * everything that wants to access the ctx.
9806 * The exception is sys_perf_event_open() /
9807 * perf_event_create_kernel_count() which does find_get_context()
9808 * without ctx::mutex (it cannot because of the move_group double mutex
9809 * lock thing). See the comments in perf_install_in_context().
9811 mutex_lock(&child_ctx->mutex);
9814 * In a single ctx::lock section, de-schedule the events and detach the
9815 * context from the task such that we cannot ever get it scheduled back
9818 raw_spin_lock_irq(&child_ctx->lock);
9819 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
9822 * Now that the context is inactive, destroy the task <-> ctx relation
9823 * and mark the context dead.
9825 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
9826 put_ctx(child_ctx); /* cannot be last */
9827 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
9828 put_task_struct(current); /* cannot be last */
9830 clone_ctx = unclone_ctx(child_ctx);
9831 raw_spin_unlock_irq(&child_ctx->lock);
9837 * Report the task dead after unscheduling the events so that we
9838 * won't get any samples after PERF_RECORD_EXIT. We can however still
9839 * get a few PERF_RECORD_READ events.
9841 perf_event_task(child, child_ctx, 0);
9843 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9844 perf_event_exit_event(child_event, child_ctx, child);
9846 mutex_unlock(&child_ctx->mutex);
9852 * When a child task exits, feed back event values to parent events.
9854 * Can be called with cred_guard_mutex held when called from
9855 * install_exec_creds().
9857 void perf_event_exit_task(struct task_struct *child)
9859 struct perf_event *event, *tmp;
9862 mutex_lock(&child->perf_event_mutex);
9863 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9865 list_del_init(&event->owner_entry);
9868 * Ensure the list deletion is visible before we clear
9869 * the owner, closes a race against perf_release() where
9870 * we need to serialize on the owner->perf_event_mutex.
9872 smp_store_release(&event->owner, NULL);
9874 mutex_unlock(&child->perf_event_mutex);
9876 for_each_task_context_nr(ctxn)
9877 perf_event_exit_task_context(child, ctxn);
9880 * The perf_event_exit_task_context calls perf_event_task
9881 * with child's task_ctx, which generates EXIT events for
9882 * child contexts and sets child->perf_event_ctxp[] to NULL.
9883 * At this point we need to send EXIT events to cpu contexts.
9885 perf_event_task(child, NULL, 0);
9888 static void perf_free_event(struct perf_event *event,
9889 struct perf_event_context *ctx)
9891 struct perf_event *parent = event->parent;
9893 if (WARN_ON_ONCE(!parent))
9896 mutex_lock(&parent->child_mutex);
9897 list_del_init(&event->child_list);
9898 mutex_unlock(&parent->child_mutex);
9902 raw_spin_lock_irq(&ctx->lock);
9903 perf_group_detach(event);
9904 list_del_event(event, ctx);
9905 raw_spin_unlock_irq(&ctx->lock);
9910 * Free an unexposed, unused context as created by inheritance by
9911 * perf_event_init_task below, used by fork() in case of fail.
9913 * Not all locks are strictly required, but take them anyway to be nice and
9914 * help out with the lockdep assertions.
9916 void perf_event_free_task(struct task_struct *task)
9918 struct perf_event_context *ctx;
9919 struct perf_event *event, *tmp;
9922 for_each_task_context_nr(ctxn) {
9923 ctx = task->perf_event_ctxp[ctxn];
9927 mutex_lock(&ctx->mutex);
9929 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9931 perf_free_event(event, ctx);
9933 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9935 perf_free_event(event, ctx);
9937 if (!list_empty(&ctx->pinned_groups) ||
9938 !list_empty(&ctx->flexible_groups))
9941 mutex_unlock(&ctx->mutex);
9947 void perf_event_delayed_put(struct task_struct *task)
9951 for_each_task_context_nr(ctxn)
9952 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9955 struct file *perf_event_get(unsigned int fd)
9959 file = fget_raw(fd);
9961 return ERR_PTR(-EBADF);
9963 if (file->f_op != &perf_fops) {
9965 return ERR_PTR(-EBADF);
9971 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9974 return ERR_PTR(-EINVAL);
9976 return &event->attr;
9980 * inherit a event from parent task to child task:
9982 static struct perf_event *
9983 inherit_event(struct perf_event *parent_event,
9984 struct task_struct *parent,
9985 struct perf_event_context *parent_ctx,
9986 struct task_struct *child,
9987 struct perf_event *group_leader,
9988 struct perf_event_context *child_ctx)
9990 enum perf_event_active_state parent_state = parent_event->state;
9991 struct perf_event *child_event;
9992 unsigned long flags;
9995 * Instead of creating recursive hierarchies of events,
9996 * we link inherited events back to the original parent,
9997 * which has a filp for sure, which we use as the reference
10000 if (parent_event->parent)
10001 parent_event = parent_event->parent;
10003 child_event = perf_event_alloc(&parent_event->attr,
10006 group_leader, parent_event,
10008 if (IS_ERR(child_event))
10009 return child_event;
10012 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10013 * must be under the same lock in order to serialize against
10014 * perf_event_release_kernel(), such that either we must observe
10015 * is_orphaned_event() or they will observe us on the child_list.
10017 mutex_lock(&parent_event->child_mutex);
10018 if (is_orphaned_event(parent_event) ||
10019 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10020 mutex_unlock(&parent_event->child_mutex);
10021 free_event(child_event);
10025 get_ctx(child_ctx);
10028 * Make the child state follow the state of the parent event,
10029 * not its attr.disabled bit. We hold the parent's mutex,
10030 * so we won't race with perf_event_{en, dis}able_family.
10032 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10033 child_event->state = PERF_EVENT_STATE_INACTIVE;
10035 child_event->state = PERF_EVENT_STATE_OFF;
10037 if (parent_event->attr.freq) {
10038 u64 sample_period = parent_event->hw.sample_period;
10039 struct hw_perf_event *hwc = &child_event->hw;
10041 hwc->sample_period = sample_period;
10042 hwc->last_period = sample_period;
10044 local64_set(&hwc->period_left, sample_period);
10047 child_event->ctx = child_ctx;
10048 child_event->overflow_handler = parent_event->overflow_handler;
10049 child_event->overflow_handler_context
10050 = parent_event->overflow_handler_context;
10053 * Precalculate sample_data sizes
10055 perf_event__header_size(child_event);
10056 perf_event__id_header_size(child_event);
10059 * Link it up in the child's context:
10061 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10062 add_event_to_ctx(child_event, child_ctx);
10063 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10066 * Link this into the parent event's child list
10068 list_add_tail(&child_event->child_list, &parent_event->child_list);
10069 mutex_unlock(&parent_event->child_mutex);
10071 return child_event;
10074 static int inherit_group(struct perf_event *parent_event,
10075 struct task_struct *parent,
10076 struct perf_event_context *parent_ctx,
10077 struct task_struct *child,
10078 struct perf_event_context *child_ctx)
10080 struct perf_event *leader;
10081 struct perf_event *sub;
10082 struct perf_event *child_ctr;
10084 leader = inherit_event(parent_event, parent, parent_ctx,
10085 child, NULL, child_ctx);
10086 if (IS_ERR(leader))
10087 return PTR_ERR(leader);
10088 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10089 child_ctr = inherit_event(sub, parent, parent_ctx,
10090 child, leader, child_ctx);
10091 if (IS_ERR(child_ctr))
10092 return PTR_ERR(child_ctr);
10098 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10099 struct perf_event_context *parent_ctx,
10100 struct task_struct *child, int ctxn,
10101 int *inherited_all)
10104 struct perf_event_context *child_ctx;
10106 if (!event->attr.inherit) {
10107 *inherited_all = 0;
10111 child_ctx = child->perf_event_ctxp[ctxn];
10114 * This is executed from the parent task context, so
10115 * inherit events that have been marked for cloning.
10116 * First allocate and initialize a context for the
10120 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10124 child->perf_event_ctxp[ctxn] = child_ctx;
10127 ret = inherit_group(event, parent, parent_ctx,
10131 *inherited_all = 0;
10137 * Initialize the perf_event context in task_struct
10139 static int perf_event_init_context(struct task_struct *child, int ctxn)
10141 struct perf_event_context *child_ctx, *parent_ctx;
10142 struct perf_event_context *cloned_ctx;
10143 struct perf_event *event;
10144 struct task_struct *parent = current;
10145 int inherited_all = 1;
10146 unsigned long flags;
10149 if (likely(!parent->perf_event_ctxp[ctxn]))
10153 * If the parent's context is a clone, pin it so it won't get
10154 * swapped under us.
10156 parent_ctx = perf_pin_task_context(parent, ctxn);
10161 * No need to check if parent_ctx != NULL here; since we saw
10162 * it non-NULL earlier, the only reason for it to become NULL
10163 * is if we exit, and since we're currently in the middle of
10164 * a fork we can't be exiting at the same time.
10168 * Lock the parent list. No need to lock the child - not PID
10169 * hashed yet and not running, so nobody can access it.
10171 mutex_lock(&parent_ctx->mutex);
10174 * We dont have to disable NMIs - we are only looking at
10175 * the list, not manipulating it:
10177 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10178 ret = inherit_task_group(event, parent, parent_ctx,
10179 child, ctxn, &inherited_all);
10185 * We can't hold ctx->lock when iterating the ->flexible_group list due
10186 * to allocations, but we need to prevent rotation because
10187 * rotate_ctx() will change the list from interrupt context.
10189 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10190 parent_ctx->rotate_disable = 1;
10191 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10193 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10194 ret = inherit_task_group(event, parent, parent_ctx,
10195 child, ctxn, &inherited_all);
10200 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10201 parent_ctx->rotate_disable = 0;
10203 child_ctx = child->perf_event_ctxp[ctxn];
10205 if (child_ctx && inherited_all) {
10207 * Mark the child context as a clone of the parent
10208 * context, or of whatever the parent is a clone of.
10210 * Note that if the parent is a clone, the holding of
10211 * parent_ctx->lock avoids it from being uncloned.
10213 cloned_ctx = parent_ctx->parent_ctx;
10215 child_ctx->parent_ctx = cloned_ctx;
10216 child_ctx->parent_gen = parent_ctx->parent_gen;
10218 child_ctx->parent_ctx = parent_ctx;
10219 child_ctx->parent_gen = parent_ctx->generation;
10221 get_ctx(child_ctx->parent_ctx);
10224 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10225 mutex_unlock(&parent_ctx->mutex);
10227 perf_unpin_context(parent_ctx);
10228 put_ctx(parent_ctx);
10234 * Initialize the perf_event context in task_struct
10236 int perf_event_init_task(struct task_struct *child)
10240 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10241 mutex_init(&child->perf_event_mutex);
10242 INIT_LIST_HEAD(&child->perf_event_list);
10244 for_each_task_context_nr(ctxn) {
10245 ret = perf_event_init_context(child, ctxn);
10247 perf_event_free_task(child);
10255 static void __init perf_event_init_all_cpus(void)
10257 struct swevent_htable *swhash;
10260 for_each_possible_cpu(cpu) {
10261 swhash = &per_cpu(swevent_htable, cpu);
10262 mutex_init(&swhash->hlist_mutex);
10263 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10265 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10266 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10270 static void perf_event_init_cpu(int cpu)
10272 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10274 mutex_lock(&swhash->hlist_mutex);
10275 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10276 struct swevent_hlist *hlist;
10278 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10280 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10282 mutex_unlock(&swhash->hlist_mutex);
10285 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10286 static void __perf_event_exit_context(void *__info)
10288 struct perf_event_context *ctx = __info;
10289 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10290 struct perf_event *event;
10292 raw_spin_lock(&ctx->lock);
10293 list_for_each_entry(event, &ctx->event_list, event_entry)
10294 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10295 raw_spin_unlock(&ctx->lock);
10298 static void perf_event_exit_cpu_context(int cpu)
10300 struct perf_event_context *ctx;
10304 idx = srcu_read_lock(&pmus_srcu);
10305 list_for_each_entry_rcu(pmu, &pmus, entry) {
10306 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10308 mutex_lock(&ctx->mutex);
10309 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10310 mutex_unlock(&ctx->mutex);
10312 srcu_read_unlock(&pmus_srcu, idx);
10315 static void perf_event_exit_cpu(int cpu)
10317 perf_event_exit_cpu_context(cpu);
10320 static inline void perf_event_exit_cpu(int cpu) { }
10324 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10328 for_each_online_cpu(cpu)
10329 perf_event_exit_cpu(cpu);
10335 * Run the perf reboot notifier at the very last possible moment so that
10336 * the generic watchdog code runs as long as possible.
10338 static struct notifier_block perf_reboot_notifier = {
10339 .notifier_call = perf_reboot,
10340 .priority = INT_MIN,
10344 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
10346 unsigned int cpu = (long)hcpu;
10348 switch (action & ~CPU_TASKS_FROZEN) {
10350 case CPU_UP_PREPARE:
10352 * This must be done before the CPU comes alive, because the
10353 * moment we can run tasks we can encounter (software) events.
10355 * Specifically, someone can have inherited events on kthreadd
10356 * or a pre-existing worker thread that gets re-bound.
10358 perf_event_init_cpu(cpu);
10361 case CPU_DOWN_PREPARE:
10363 * This must be done before the CPU dies because after that an
10364 * active event might want to IPI the CPU and that'll not work
10365 * so great for dead CPUs.
10367 * XXX smp_call_function_single() return -ENXIO without a warn
10368 * so we could possibly deal with this.
10370 * This is safe against new events arriving because
10371 * sys_perf_event_open() serializes against hotplug using
10372 * get_online_cpus().
10374 perf_event_exit_cpu(cpu);
10383 void __init perf_event_init(void)
10387 idr_init(&pmu_idr);
10389 perf_event_init_all_cpus();
10390 init_srcu_struct(&pmus_srcu);
10391 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10392 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10393 perf_pmu_register(&perf_task_clock, NULL, -1);
10394 perf_tp_register();
10395 perf_cpu_notifier(perf_cpu_notify);
10396 register_reboot_notifier(&perf_reboot_notifier);
10398 ret = init_hw_breakpoint();
10399 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10402 * Build time assertion that we keep the data_head at the intended
10403 * location. IOW, validation we got the __reserved[] size right.
10405 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10409 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10412 struct perf_pmu_events_attr *pmu_attr =
10413 container_of(attr, struct perf_pmu_events_attr, attr);
10415 if (pmu_attr->event_str)
10416 return sprintf(page, "%s\n", pmu_attr->event_str);
10420 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10422 static int __init perf_event_sysfs_init(void)
10427 mutex_lock(&pmus_lock);
10429 ret = bus_register(&pmu_bus);
10433 list_for_each_entry(pmu, &pmus, entry) {
10434 if (!pmu->name || pmu->type < 0)
10437 ret = pmu_dev_alloc(pmu);
10438 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10440 pmu_bus_running = 1;
10444 mutex_unlock(&pmus_lock);
10448 device_initcall(perf_event_sysfs_init);
10450 #ifdef CONFIG_CGROUP_PERF
10451 static struct cgroup_subsys_state *
10452 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10454 struct perf_cgroup *jc;
10456 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10458 return ERR_PTR(-ENOMEM);
10460 jc->info = alloc_percpu(struct perf_cgroup_info);
10463 return ERR_PTR(-ENOMEM);
10469 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10471 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10473 free_percpu(jc->info);
10477 static int __perf_cgroup_move(void *info)
10479 struct task_struct *task = info;
10481 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10486 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10488 struct task_struct *task;
10489 struct cgroup_subsys_state *css;
10491 cgroup_taskset_for_each(task, css, tset)
10492 task_function_call(task, __perf_cgroup_move, task);
10495 struct cgroup_subsys perf_event_cgrp_subsys = {
10496 .css_alloc = perf_cgroup_css_alloc,
10497 .css_free = perf_cgroup_css_free,
10498 .attach = perf_cgroup_attach,
10500 #endif /* CONFIG_CGROUP_PERF */