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_call(struct perf_event *event, event_f func, void *data)
247 struct perf_event_context *ctx = event->ctx;
248 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
249 struct event_function_struct efs = {
255 if (!event->parent) {
257 * If this is a !child event, we must hold ctx::mutex to
258 * stabilize the the event->ctx relation. See
259 * perf_event_ctx_lock().
261 lockdep_assert_held(&ctx->mutex);
265 cpu_function_call(event->cpu, event_function, &efs);
269 if (task == TASK_TOMBSTONE)
273 if (!task_function_call(task, event_function, &efs))
276 raw_spin_lock_irq(&ctx->lock);
278 * Reload the task pointer, it might have been changed by
279 * a concurrent perf_event_context_sched_out().
282 if (task == TASK_TOMBSTONE) {
283 raw_spin_unlock_irq(&ctx->lock);
286 if (ctx->is_active) {
287 raw_spin_unlock_irq(&ctx->lock);
290 func(event, NULL, ctx, data);
291 raw_spin_unlock_irq(&ctx->lock);
295 * Similar to event_function_call() + event_function(), but hard assumes IRQs
296 * are already disabled and we're on the right CPU.
298 static void event_function_local(struct perf_event *event, event_f func, void *data)
300 struct perf_event_context *ctx = event->ctx;
301 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
302 struct task_struct *task = READ_ONCE(ctx->task);
303 struct perf_event_context *task_ctx = NULL;
305 WARN_ON_ONCE(!irqs_disabled());
308 if (task == TASK_TOMBSTONE)
314 perf_ctx_lock(cpuctx, task_ctx);
317 if (task == TASK_TOMBSTONE)
322 * We must be either inactive or active and the right task,
323 * otherwise we're screwed, since we cannot IPI to somewhere
326 if (ctx->is_active) {
327 if (WARN_ON_ONCE(task != current))
330 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
334 WARN_ON_ONCE(&cpuctx->ctx != ctx);
337 func(event, cpuctx, ctx, data);
339 perf_ctx_unlock(cpuctx, task_ctx);
342 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
343 PERF_FLAG_FD_OUTPUT |\
344 PERF_FLAG_PID_CGROUP |\
345 PERF_FLAG_FD_CLOEXEC)
348 * branch priv levels that need permission checks
350 #define PERF_SAMPLE_BRANCH_PERM_PLM \
351 (PERF_SAMPLE_BRANCH_KERNEL |\
352 PERF_SAMPLE_BRANCH_HV)
355 EVENT_FLEXIBLE = 0x1,
358 /* see ctx_resched() for details */
360 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
364 * perf_sched_events : >0 events exist
365 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
368 static void perf_sched_delayed(struct work_struct *work);
369 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
370 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
371 static DEFINE_MUTEX(perf_sched_mutex);
372 static atomic_t perf_sched_count;
374 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
375 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
376 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
378 static atomic_t nr_mmap_events __read_mostly;
379 static atomic_t nr_comm_events __read_mostly;
380 static atomic_t nr_task_events __read_mostly;
381 static atomic_t nr_freq_events __read_mostly;
382 static atomic_t nr_switch_events __read_mostly;
384 static LIST_HEAD(pmus);
385 static DEFINE_MUTEX(pmus_lock);
386 static struct srcu_struct pmus_srcu;
389 * perf event paranoia level:
390 * -1 - not paranoid at all
391 * 0 - disallow raw tracepoint access for unpriv
392 * 1 - disallow cpu events for unpriv
393 * 2 - disallow kernel profiling for unpriv
395 int sysctl_perf_event_paranoid __read_mostly = 2;
397 /* Minimum for 512 kiB + 1 user control page */
398 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
401 * max perf event sample rate
403 #define DEFAULT_MAX_SAMPLE_RATE 100000
404 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
405 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
407 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
409 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
410 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
412 static int perf_sample_allowed_ns __read_mostly =
413 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
415 static void update_perf_cpu_limits(void)
417 u64 tmp = perf_sample_period_ns;
419 tmp *= sysctl_perf_cpu_time_max_percent;
420 tmp = div_u64(tmp, 100);
424 WRITE_ONCE(perf_sample_allowed_ns, tmp);
427 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
429 int perf_proc_update_handler(struct ctl_table *table, int write,
430 void __user *buffer, size_t *lenp,
433 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
439 * If throttling is disabled don't allow the write:
441 if (sysctl_perf_cpu_time_max_percent == 100 ||
442 sysctl_perf_cpu_time_max_percent == 0)
445 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
446 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
447 update_perf_cpu_limits();
452 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
454 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
455 void __user *buffer, size_t *lenp,
458 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
463 if (sysctl_perf_cpu_time_max_percent == 100 ||
464 sysctl_perf_cpu_time_max_percent == 0) {
466 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
467 WRITE_ONCE(perf_sample_allowed_ns, 0);
469 update_perf_cpu_limits();
476 * perf samples are done in some very critical code paths (NMIs).
477 * If they take too much CPU time, the system can lock up and not
478 * get any real work done. This will drop the sample rate when
479 * we detect that events are taking too long.
481 #define NR_ACCUMULATED_SAMPLES 128
482 static DEFINE_PER_CPU(u64, running_sample_length);
484 static u64 __report_avg;
485 static u64 __report_allowed;
487 static void perf_duration_warn(struct irq_work *w)
489 printk_ratelimited(KERN_INFO
490 "perf: interrupt took too long (%lld > %lld), lowering "
491 "kernel.perf_event_max_sample_rate to %d\n",
492 __report_avg, __report_allowed,
493 sysctl_perf_event_sample_rate);
496 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
498 void perf_sample_event_took(u64 sample_len_ns)
500 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
508 /* Decay the counter by 1 average sample. */
509 running_len = __this_cpu_read(running_sample_length);
510 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
511 running_len += sample_len_ns;
512 __this_cpu_write(running_sample_length, running_len);
515 * Note: this will be biased artifically low until we have
516 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
517 * from having to maintain a count.
519 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
520 if (avg_len <= max_len)
523 __report_avg = avg_len;
524 __report_allowed = max_len;
527 * Compute a throttle threshold 25% below the current duration.
529 avg_len += avg_len / 4;
530 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
536 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
537 WRITE_ONCE(max_samples_per_tick, max);
539 sysctl_perf_event_sample_rate = max * HZ;
540 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
542 if (!irq_work_queue(&perf_duration_work)) {
543 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
544 "kernel.perf_event_max_sample_rate to %d\n",
545 __report_avg, __report_allowed,
546 sysctl_perf_event_sample_rate);
550 static atomic64_t perf_event_id;
552 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
553 enum event_type_t event_type);
555 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
556 enum event_type_t event_type,
557 struct task_struct *task);
559 static void update_context_time(struct perf_event_context *ctx);
560 static u64 perf_event_time(struct perf_event *event);
562 void __weak perf_event_print_debug(void) { }
564 extern __weak const char *perf_pmu_name(void)
569 static inline u64 perf_clock(void)
571 return local_clock();
574 static inline u64 perf_event_clock(struct perf_event *event)
576 return event->clock();
579 #ifdef CONFIG_CGROUP_PERF
582 perf_cgroup_match(struct perf_event *event)
584 struct perf_event_context *ctx = event->ctx;
585 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
587 /* @event doesn't care about cgroup */
591 /* wants specific cgroup scope but @cpuctx isn't associated with any */
596 * Cgroup scoping is recursive. An event enabled for a cgroup is
597 * also enabled for all its descendant cgroups. If @cpuctx's
598 * cgroup is a descendant of @event's (the test covers identity
599 * case), it's a match.
601 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
602 event->cgrp->css.cgroup);
605 static inline void perf_detach_cgroup(struct perf_event *event)
607 css_put(&event->cgrp->css);
611 static inline int is_cgroup_event(struct perf_event *event)
613 return event->cgrp != NULL;
616 static inline u64 perf_cgroup_event_time(struct perf_event *event)
618 struct perf_cgroup_info *t;
620 t = per_cpu_ptr(event->cgrp->info, event->cpu);
624 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
626 struct perf_cgroup_info *info;
631 info = this_cpu_ptr(cgrp->info);
633 info->time += now - info->timestamp;
634 info->timestamp = now;
637 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
639 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
641 __update_cgrp_time(cgrp_out);
644 static inline void update_cgrp_time_from_event(struct perf_event *event)
646 struct perf_cgroup *cgrp;
649 * ensure we access cgroup data only when needed and
650 * when we know the cgroup is pinned (css_get)
652 if (!is_cgroup_event(event))
655 cgrp = perf_cgroup_from_task(current, event->ctx);
657 * Do not update time when cgroup is not active
659 if (cgrp == event->cgrp)
660 __update_cgrp_time(event->cgrp);
664 perf_cgroup_set_timestamp(struct task_struct *task,
665 struct perf_event_context *ctx)
667 struct perf_cgroup *cgrp;
668 struct perf_cgroup_info *info;
671 * ctx->lock held by caller
672 * ensure we do not access cgroup data
673 * unless we have the cgroup pinned (css_get)
675 if (!task || !ctx->nr_cgroups)
678 cgrp = perf_cgroup_from_task(task, ctx);
679 info = this_cpu_ptr(cgrp->info);
680 info->timestamp = ctx->timestamp;
683 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
685 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
686 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
689 * reschedule events based on the cgroup constraint of task.
691 * mode SWOUT : schedule out everything
692 * mode SWIN : schedule in based on cgroup for next
694 static void perf_cgroup_switch(struct task_struct *task, int mode)
696 struct perf_cpu_context *cpuctx;
697 struct list_head *list;
701 * Disable interrupts and preemption to avoid this CPU's
702 * cgrp_cpuctx_entry to change under us.
704 local_irq_save(flags);
706 list = this_cpu_ptr(&cgrp_cpuctx_list);
707 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
708 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
710 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
711 perf_pmu_disable(cpuctx->ctx.pmu);
713 if (mode & PERF_CGROUP_SWOUT) {
714 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
716 * must not be done before ctxswout due
717 * to event_filter_match() in event_sched_out()
722 if (mode & PERF_CGROUP_SWIN) {
723 WARN_ON_ONCE(cpuctx->cgrp);
725 * set cgrp before ctxsw in to allow
726 * event_filter_match() to not have to pass
728 * we pass the cpuctx->ctx to perf_cgroup_from_task()
729 * because cgorup events are only per-cpu
731 cpuctx->cgrp = perf_cgroup_from_task(task,
733 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
735 perf_pmu_enable(cpuctx->ctx.pmu);
736 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
739 local_irq_restore(flags);
742 static inline void perf_cgroup_sched_out(struct task_struct *task,
743 struct task_struct *next)
745 struct perf_cgroup *cgrp1;
746 struct perf_cgroup *cgrp2 = NULL;
750 * we come here when we know perf_cgroup_events > 0
751 * we do not need to pass the ctx here because we know
752 * we are holding the rcu lock
754 cgrp1 = perf_cgroup_from_task(task, NULL);
755 cgrp2 = perf_cgroup_from_task(next, NULL);
758 * only schedule out current cgroup events if we know
759 * that we are switching to a different cgroup. Otherwise,
760 * do no touch the cgroup events.
763 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
768 static inline void perf_cgroup_sched_in(struct task_struct *prev,
769 struct task_struct *task)
771 struct perf_cgroup *cgrp1;
772 struct perf_cgroup *cgrp2 = NULL;
776 * we come here when we know perf_cgroup_events > 0
777 * we do not need to pass the ctx here because we know
778 * we are holding the rcu lock
780 cgrp1 = perf_cgroup_from_task(task, NULL);
781 cgrp2 = perf_cgroup_from_task(prev, NULL);
784 * only need to schedule in cgroup events if we are changing
785 * cgroup during ctxsw. Cgroup events were not scheduled
786 * out of ctxsw out if that was not the case.
789 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
794 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
795 struct perf_event_attr *attr,
796 struct perf_event *group_leader)
798 struct perf_cgroup *cgrp;
799 struct cgroup_subsys_state *css;
800 struct fd f = fdget(fd);
806 css = css_tryget_online_from_dir(f.file->f_path.dentry,
807 &perf_event_cgrp_subsys);
813 cgrp = container_of(css, struct perf_cgroup, css);
817 * all events in a group must monitor
818 * the same cgroup because a task belongs
819 * to only one perf cgroup at a time
821 if (group_leader && group_leader->cgrp != cgrp) {
822 perf_detach_cgroup(event);
831 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
833 struct perf_cgroup_info *t;
834 t = per_cpu_ptr(event->cgrp->info, event->cpu);
835 event->shadow_ctx_time = now - t->timestamp;
839 perf_cgroup_defer_enabled(struct perf_event *event)
842 * when the current task's perf cgroup does not match
843 * the event's, we need to remember to call the
844 * perf_mark_enable() function the first time a task with
845 * a matching perf cgroup is scheduled in.
847 if (is_cgroup_event(event) && !perf_cgroup_match(event))
848 event->cgrp_defer_enabled = 1;
852 perf_cgroup_mark_enabled(struct perf_event *event,
853 struct perf_event_context *ctx)
855 struct perf_event *sub;
856 u64 tstamp = perf_event_time(event);
858 if (!event->cgrp_defer_enabled)
861 event->cgrp_defer_enabled = 0;
863 event->tstamp_enabled = tstamp - event->total_time_enabled;
864 list_for_each_entry(sub, &event->sibling_list, group_entry) {
865 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
866 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
867 sub->cgrp_defer_enabled = 0;
873 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
874 * cleared when last cgroup event is removed.
877 list_update_cgroup_event(struct perf_event *event,
878 struct perf_event_context *ctx, bool add)
880 struct perf_cpu_context *cpuctx;
881 struct list_head *cpuctx_entry;
883 if (!is_cgroup_event(event))
886 if (add && ctx->nr_cgroups++)
888 else if (!add && --ctx->nr_cgroups)
891 * Because cgroup events are always per-cpu events,
892 * this will always be called from the right CPU.
894 cpuctx = __get_cpu_context(ctx);
895 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
896 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
898 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
899 if (perf_cgroup_from_task(current, ctx) == event->cgrp)
900 cpuctx->cgrp = event->cgrp;
902 list_del(cpuctx_entry);
907 #else /* !CONFIG_CGROUP_PERF */
910 perf_cgroup_match(struct perf_event *event)
915 static inline void perf_detach_cgroup(struct perf_event *event)
918 static inline int is_cgroup_event(struct perf_event *event)
923 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
928 static inline void update_cgrp_time_from_event(struct perf_event *event)
932 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
936 static inline void perf_cgroup_sched_out(struct task_struct *task,
937 struct task_struct *next)
941 static inline void perf_cgroup_sched_in(struct task_struct *prev,
942 struct task_struct *task)
946 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
947 struct perf_event_attr *attr,
948 struct perf_event *group_leader)
954 perf_cgroup_set_timestamp(struct task_struct *task,
955 struct perf_event_context *ctx)
960 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
965 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
969 static inline u64 perf_cgroup_event_time(struct perf_event *event)
975 perf_cgroup_defer_enabled(struct perf_event *event)
980 perf_cgroup_mark_enabled(struct perf_event *event,
981 struct perf_event_context *ctx)
986 list_update_cgroup_event(struct perf_event *event,
987 struct perf_event_context *ctx, bool add)
994 * set default to be dependent on timer tick just
997 #define PERF_CPU_HRTIMER (1000 / HZ)
999 * function must be called with interrupts disbled
1001 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1003 struct perf_cpu_context *cpuctx;
1006 WARN_ON(!irqs_disabled());
1008 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1009 rotations = perf_rotate_context(cpuctx);
1011 raw_spin_lock(&cpuctx->hrtimer_lock);
1013 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1015 cpuctx->hrtimer_active = 0;
1016 raw_spin_unlock(&cpuctx->hrtimer_lock);
1018 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1021 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1023 struct hrtimer *timer = &cpuctx->hrtimer;
1024 struct pmu *pmu = cpuctx->ctx.pmu;
1027 /* no multiplexing needed for SW PMU */
1028 if (pmu->task_ctx_nr == perf_sw_context)
1032 * check default is sane, if not set then force to
1033 * default interval (1/tick)
1035 interval = pmu->hrtimer_interval_ms;
1037 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1039 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1041 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1042 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1043 timer->function = perf_mux_hrtimer_handler;
1046 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1048 struct hrtimer *timer = &cpuctx->hrtimer;
1049 struct pmu *pmu = cpuctx->ctx.pmu;
1050 unsigned long flags;
1052 /* not for SW PMU */
1053 if (pmu->task_ctx_nr == perf_sw_context)
1056 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1057 if (!cpuctx->hrtimer_active) {
1058 cpuctx->hrtimer_active = 1;
1059 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1060 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1062 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1067 void perf_pmu_disable(struct pmu *pmu)
1069 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1071 pmu->pmu_disable(pmu);
1074 void perf_pmu_enable(struct pmu *pmu)
1076 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1078 pmu->pmu_enable(pmu);
1081 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1084 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1085 * perf_event_task_tick() are fully serialized because they're strictly cpu
1086 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1087 * disabled, while perf_event_task_tick is called from IRQ context.
1089 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1091 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1093 WARN_ON(!irqs_disabled());
1095 WARN_ON(!list_empty(&ctx->active_ctx_list));
1097 list_add(&ctx->active_ctx_list, head);
1100 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1102 WARN_ON(!irqs_disabled());
1104 WARN_ON(list_empty(&ctx->active_ctx_list));
1106 list_del_init(&ctx->active_ctx_list);
1109 static void get_ctx(struct perf_event_context *ctx)
1111 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1114 static void free_ctx(struct rcu_head *head)
1116 struct perf_event_context *ctx;
1118 ctx = container_of(head, struct perf_event_context, rcu_head);
1119 kfree(ctx->task_ctx_data);
1123 static void put_ctx(struct perf_event_context *ctx)
1125 if (atomic_dec_and_test(&ctx->refcount)) {
1126 if (ctx->parent_ctx)
1127 put_ctx(ctx->parent_ctx);
1128 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1129 put_task_struct(ctx->task);
1130 call_rcu(&ctx->rcu_head, free_ctx);
1135 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1136 * perf_pmu_migrate_context() we need some magic.
1138 * Those places that change perf_event::ctx will hold both
1139 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1141 * Lock ordering is by mutex address. There are two other sites where
1142 * perf_event_context::mutex nests and those are:
1144 * - perf_event_exit_task_context() [ child , 0 ]
1145 * perf_event_exit_event()
1146 * put_event() [ parent, 1 ]
1148 * - perf_event_init_context() [ parent, 0 ]
1149 * inherit_task_group()
1152 * perf_event_alloc()
1154 * perf_try_init_event() [ child , 1 ]
1156 * While it appears there is an obvious deadlock here -- the parent and child
1157 * nesting levels are inverted between the two. This is in fact safe because
1158 * life-time rules separate them. That is an exiting task cannot fork, and a
1159 * spawning task cannot (yet) exit.
1161 * But remember that that these are parent<->child context relations, and
1162 * migration does not affect children, therefore these two orderings should not
1165 * The change in perf_event::ctx does not affect children (as claimed above)
1166 * because the sys_perf_event_open() case will install a new event and break
1167 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1168 * concerned with cpuctx and that doesn't have children.
1170 * The places that change perf_event::ctx will issue:
1172 * perf_remove_from_context();
1173 * synchronize_rcu();
1174 * perf_install_in_context();
1176 * to affect the change. The remove_from_context() + synchronize_rcu() should
1177 * quiesce the event, after which we can install it in the new location. This
1178 * means that only external vectors (perf_fops, prctl) can perturb the event
1179 * while in transit. Therefore all such accessors should also acquire
1180 * perf_event_context::mutex to serialize against this.
1182 * However; because event->ctx can change while we're waiting to acquire
1183 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1188 * task_struct::perf_event_mutex
1189 * perf_event_context::mutex
1190 * perf_event::child_mutex;
1191 * perf_event_context::lock
1192 * perf_event::mmap_mutex
1195 static struct perf_event_context *
1196 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1198 struct perf_event_context *ctx;
1202 ctx = ACCESS_ONCE(event->ctx);
1203 if (!atomic_inc_not_zero(&ctx->refcount)) {
1209 mutex_lock_nested(&ctx->mutex, nesting);
1210 if (event->ctx != ctx) {
1211 mutex_unlock(&ctx->mutex);
1219 static inline struct perf_event_context *
1220 perf_event_ctx_lock(struct perf_event *event)
1222 return perf_event_ctx_lock_nested(event, 0);
1225 static void perf_event_ctx_unlock(struct perf_event *event,
1226 struct perf_event_context *ctx)
1228 mutex_unlock(&ctx->mutex);
1233 * This must be done under the ctx->lock, such as to serialize against
1234 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1235 * calling scheduler related locks and ctx->lock nests inside those.
1237 static __must_check struct perf_event_context *
1238 unclone_ctx(struct perf_event_context *ctx)
1240 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1242 lockdep_assert_held(&ctx->lock);
1245 ctx->parent_ctx = NULL;
1251 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1254 * only top level events have the pid namespace they were created in
1257 event = event->parent;
1259 return task_tgid_nr_ns(p, event->ns);
1262 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1265 * only top level events have the pid namespace they were created in
1268 event = event->parent;
1270 return task_pid_nr_ns(p, event->ns);
1274 * If we inherit events we want to return the parent event id
1277 static u64 primary_event_id(struct perf_event *event)
1282 id = event->parent->id;
1288 * Get the perf_event_context for a task and lock it.
1290 * This has to cope with with the fact that until it is locked,
1291 * the context could get moved to another task.
1293 static struct perf_event_context *
1294 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1296 struct perf_event_context *ctx;
1300 * One of the few rules of preemptible RCU is that one cannot do
1301 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1302 * part of the read side critical section was irqs-enabled -- see
1303 * rcu_read_unlock_special().
1305 * Since ctx->lock nests under rq->lock we must ensure the entire read
1306 * side critical section has interrupts disabled.
1308 local_irq_save(*flags);
1310 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1313 * If this context is a clone of another, it might
1314 * get swapped for another underneath us by
1315 * perf_event_task_sched_out, though the
1316 * rcu_read_lock() protects us from any context
1317 * getting freed. Lock the context and check if it
1318 * got swapped before we could get the lock, and retry
1319 * if so. If we locked the right context, then it
1320 * can't get swapped on us any more.
1322 raw_spin_lock(&ctx->lock);
1323 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1324 raw_spin_unlock(&ctx->lock);
1326 local_irq_restore(*flags);
1330 if (ctx->task == TASK_TOMBSTONE ||
1331 !atomic_inc_not_zero(&ctx->refcount)) {
1332 raw_spin_unlock(&ctx->lock);
1335 WARN_ON_ONCE(ctx->task != task);
1340 local_irq_restore(*flags);
1345 * Get the context for a task and increment its pin_count so it
1346 * can't get swapped to another task. This also increments its
1347 * reference count so that the context can't get freed.
1349 static struct perf_event_context *
1350 perf_pin_task_context(struct task_struct *task, int ctxn)
1352 struct perf_event_context *ctx;
1353 unsigned long flags;
1355 ctx = perf_lock_task_context(task, ctxn, &flags);
1358 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1363 static void perf_unpin_context(struct perf_event_context *ctx)
1365 unsigned long flags;
1367 raw_spin_lock_irqsave(&ctx->lock, flags);
1369 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1373 * Update the record of the current time in a context.
1375 static void update_context_time(struct perf_event_context *ctx)
1377 u64 now = perf_clock();
1379 ctx->time += now - ctx->timestamp;
1380 ctx->timestamp = now;
1383 static u64 perf_event_time(struct perf_event *event)
1385 struct perf_event_context *ctx = event->ctx;
1387 if (is_cgroup_event(event))
1388 return perf_cgroup_event_time(event);
1390 return ctx ? ctx->time : 0;
1394 * Update the total_time_enabled and total_time_running fields for a event.
1396 static void update_event_times(struct perf_event *event)
1398 struct perf_event_context *ctx = event->ctx;
1401 lockdep_assert_held(&ctx->lock);
1403 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1404 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1408 * in cgroup mode, time_enabled represents
1409 * the time the event was enabled AND active
1410 * tasks were in the monitored cgroup. This is
1411 * independent of the activity of the context as
1412 * there may be a mix of cgroup and non-cgroup events.
1414 * That is why we treat cgroup events differently
1417 if (is_cgroup_event(event))
1418 run_end = perf_cgroup_event_time(event);
1419 else if (ctx->is_active)
1420 run_end = ctx->time;
1422 run_end = event->tstamp_stopped;
1424 event->total_time_enabled = run_end - event->tstamp_enabled;
1426 if (event->state == PERF_EVENT_STATE_INACTIVE)
1427 run_end = event->tstamp_stopped;
1429 run_end = perf_event_time(event);
1431 event->total_time_running = run_end - event->tstamp_running;
1436 * Update total_time_enabled and total_time_running for all events in a group.
1438 static void update_group_times(struct perf_event *leader)
1440 struct perf_event *event;
1442 update_event_times(leader);
1443 list_for_each_entry(event, &leader->sibling_list, group_entry)
1444 update_event_times(event);
1447 static enum event_type_t get_event_type(struct perf_event *event)
1449 struct perf_event_context *ctx = event->ctx;
1450 enum event_type_t event_type;
1452 lockdep_assert_held(&ctx->lock);
1454 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1456 event_type |= EVENT_CPU;
1461 static struct list_head *
1462 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1464 if (event->attr.pinned)
1465 return &ctx->pinned_groups;
1467 return &ctx->flexible_groups;
1471 * Add a event from the lists for its context.
1472 * Must be called with ctx->mutex and ctx->lock held.
1475 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1477 lockdep_assert_held(&ctx->lock);
1479 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1480 event->attach_state |= PERF_ATTACH_CONTEXT;
1483 * If we're a stand alone event or group leader, we go to the context
1484 * list, group events are kept attached to the group so that
1485 * perf_group_detach can, at all times, locate all siblings.
1487 if (event->group_leader == event) {
1488 struct list_head *list;
1490 event->group_caps = event->event_caps;
1492 list = ctx_group_list(event, ctx);
1493 list_add_tail(&event->group_entry, list);
1496 list_update_cgroup_event(event, ctx, true);
1498 list_add_rcu(&event->event_entry, &ctx->event_list);
1500 if (event->attr.inherit_stat)
1507 * Initialize event state based on the perf_event_attr::disabled.
1509 static inline void perf_event__state_init(struct perf_event *event)
1511 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1512 PERF_EVENT_STATE_INACTIVE;
1515 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1517 int entry = sizeof(u64); /* value */
1521 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1522 size += sizeof(u64);
1524 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1525 size += sizeof(u64);
1527 if (event->attr.read_format & PERF_FORMAT_ID)
1528 entry += sizeof(u64);
1530 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1532 size += sizeof(u64);
1536 event->read_size = size;
1539 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1541 struct perf_sample_data *data;
1544 if (sample_type & PERF_SAMPLE_IP)
1545 size += sizeof(data->ip);
1547 if (sample_type & PERF_SAMPLE_ADDR)
1548 size += sizeof(data->addr);
1550 if (sample_type & PERF_SAMPLE_PERIOD)
1551 size += sizeof(data->period);
1553 if (sample_type & PERF_SAMPLE_WEIGHT)
1554 size += sizeof(data->weight);
1556 if (sample_type & PERF_SAMPLE_READ)
1557 size += event->read_size;
1559 if (sample_type & PERF_SAMPLE_DATA_SRC)
1560 size += sizeof(data->data_src.val);
1562 if (sample_type & PERF_SAMPLE_TRANSACTION)
1563 size += sizeof(data->txn);
1565 event->header_size = size;
1569 * Called at perf_event creation and when events are attached/detached from a
1572 static void perf_event__header_size(struct perf_event *event)
1574 __perf_event_read_size(event,
1575 event->group_leader->nr_siblings);
1576 __perf_event_header_size(event, event->attr.sample_type);
1579 static void perf_event__id_header_size(struct perf_event *event)
1581 struct perf_sample_data *data;
1582 u64 sample_type = event->attr.sample_type;
1585 if (sample_type & PERF_SAMPLE_TID)
1586 size += sizeof(data->tid_entry);
1588 if (sample_type & PERF_SAMPLE_TIME)
1589 size += sizeof(data->time);
1591 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1592 size += sizeof(data->id);
1594 if (sample_type & PERF_SAMPLE_ID)
1595 size += sizeof(data->id);
1597 if (sample_type & PERF_SAMPLE_STREAM_ID)
1598 size += sizeof(data->stream_id);
1600 if (sample_type & PERF_SAMPLE_CPU)
1601 size += sizeof(data->cpu_entry);
1603 event->id_header_size = size;
1606 static bool perf_event_validate_size(struct perf_event *event)
1609 * The values computed here will be over-written when we actually
1612 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1613 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1614 perf_event__id_header_size(event);
1617 * Sum the lot; should not exceed the 64k limit we have on records.
1618 * Conservative limit to allow for callchains and other variable fields.
1620 if (event->read_size + event->header_size +
1621 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1627 static void perf_group_attach(struct perf_event *event)
1629 struct perf_event *group_leader = event->group_leader, *pos;
1631 lockdep_assert_held(&event->ctx->lock);
1634 * We can have double attach due to group movement in perf_event_open.
1636 if (event->attach_state & PERF_ATTACH_GROUP)
1639 event->attach_state |= PERF_ATTACH_GROUP;
1641 if (group_leader == event)
1644 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1646 group_leader->group_caps &= event->event_caps;
1648 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1649 group_leader->nr_siblings++;
1651 perf_event__header_size(group_leader);
1653 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1654 perf_event__header_size(pos);
1658 * Remove a event from the lists for its context.
1659 * Must be called with ctx->mutex and ctx->lock held.
1662 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1664 WARN_ON_ONCE(event->ctx != ctx);
1665 lockdep_assert_held(&ctx->lock);
1668 * We can have double detach due to exit/hot-unplug + close.
1670 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1673 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1675 list_update_cgroup_event(event, ctx, false);
1678 if (event->attr.inherit_stat)
1681 list_del_rcu(&event->event_entry);
1683 if (event->group_leader == event)
1684 list_del_init(&event->group_entry);
1686 update_group_times(event);
1689 * If event was in error state, then keep it
1690 * that way, otherwise bogus counts will be
1691 * returned on read(). The only way to get out
1692 * of error state is by explicit re-enabling
1695 if (event->state > PERF_EVENT_STATE_OFF)
1696 event->state = PERF_EVENT_STATE_OFF;
1701 static void perf_group_detach(struct perf_event *event)
1703 struct perf_event *sibling, *tmp;
1704 struct list_head *list = NULL;
1706 lockdep_assert_held(&event->ctx->lock);
1709 * We can have double detach due to exit/hot-unplug + close.
1711 if (!(event->attach_state & PERF_ATTACH_GROUP))
1714 event->attach_state &= ~PERF_ATTACH_GROUP;
1717 * If this is a sibling, remove it from its group.
1719 if (event->group_leader != event) {
1720 list_del_init(&event->group_entry);
1721 event->group_leader->nr_siblings--;
1725 if (!list_empty(&event->group_entry))
1726 list = &event->group_entry;
1729 * If this was a group event with sibling events then
1730 * upgrade the siblings to singleton events by adding them
1731 * to whatever list we are on.
1733 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1735 list_move_tail(&sibling->group_entry, list);
1736 sibling->group_leader = sibling;
1738 /* Inherit group flags from the previous leader */
1739 sibling->group_caps = event->group_caps;
1741 WARN_ON_ONCE(sibling->ctx != event->ctx);
1745 perf_event__header_size(event->group_leader);
1747 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1748 perf_event__header_size(tmp);
1751 static bool is_orphaned_event(struct perf_event *event)
1753 return event->state == PERF_EVENT_STATE_DEAD;
1756 static inline int __pmu_filter_match(struct perf_event *event)
1758 struct pmu *pmu = event->pmu;
1759 return pmu->filter_match ? pmu->filter_match(event) : 1;
1763 * Check whether we should attempt to schedule an event group based on
1764 * PMU-specific filtering. An event group can consist of HW and SW events,
1765 * potentially with a SW leader, so we must check all the filters, to
1766 * determine whether a group is schedulable:
1768 static inline int pmu_filter_match(struct perf_event *event)
1770 struct perf_event *child;
1772 if (!__pmu_filter_match(event))
1775 list_for_each_entry(child, &event->sibling_list, group_entry) {
1776 if (!__pmu_filter_match(child))
1784 event_filter_match(struct perf_event *event)
1786 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1787 perf_cgroup_match(event) && pmu_filter_match(event);
1791 event_sched_out(struct perf_event *event,
1792 struct perf_cpu_context *cpuctx,
1793 struct perf_event_context *ctx)
1795 u64 tstamp = perf_event_time(event);
1798 WARN_ON_ONCE(event->ctx != ctx);
1799 lockdep_assert_held(&ctx->lock);
1802 * An event which could not be activated because of
1803 * filter mismatch still needs to have its timings
1804 * maintained, otherwise bogus information is return
1805 * via read() for time_enabled, time_running:
1807 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1808 !event_filter_match(event)) {
1809 delta = tstamp - event->tstamp_stopped;
1810 event->tstamp_running += delta;
1811 event->tstamp_stopped = tstamp;
1814 if (event->state != PERF_EVENT_STATE_ACTIVE)
1817 perf_pmu_disable(event->pmu);
1819 event->tstamp_stopped = tstamp;
1820 event->pmu->del(event, 0);
1822 event->state = PERF_EVENT_STATE_INACTIVE;
1823 if (event->pending_disable) {
1824 event->pending_disable = 0;
1825 event->state = PERF_EVENT_STATE_OFF;
1828 if (!is_software_event(event))
1829 cpuctx->active_oncpu--;
1830 if (!--ctx->nr_active)
1831 perf_event_ctx_deactivate(ctx);
1832 if (event->attr.freq && event->attr.sample_freq)
1834 if (event->attr.exclusive || !cpuctx->active_oncpu)
1835 cpuctx->exclusive = 0;
1837 perf_pmu_enable(event->pmu);
1841 group_sched_out(struct perf_event *group_event,
1842 struct perf_cpu_context *cpuctx,
1843 struct perf_event_context *ctx)
1845 struct perf_event *event;
1846 int state = group_event->state;
1848 perf_pmu_disable(ctx->pmu);
1850 event_sched_out(group_event, cpuctx, ctx);
1853 * Schedule out siblings (if any):
1855 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1856 event_sched_out(event, cpuctx, ctx);
1858 perf_pmu_enable(ctx->pmu);
1860 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1861 cpuctx->exclusive = 0;
1864 #define DETACH_GROUP 0x01UL
1867 * Cross CPU call to remove a performance event
1869 * We disable the event on the hardware level first. After that we
1870 * remove it from the context list.
1873 __perf_remove_from_context(struct perf_event *event,
1874 struct perf_cpu_context *cpuctx,
1875 struct perf_event_context *ctx,
1878 unsigned long flags = (unsigned long)info;
1880 event_sched_out(event, cpuctx, ctx);
1881 if (flags & DETACH_GROUP)
1882 perf_group_detach(event);
1883 list_del_event(event, ctx);
1885 if (!ctx->nr_events && ctx->is_active) {
1888 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1889 cpuctx->task_ctx = NULL;
1895 * Remove the event from a task's (or a CPU's) list of events.
1897 * If event->ctx is a cloned context, callers must make sure that
1898 * every task struct that event->ctx->task could possibly point to
1899 * remains valid. This is OK when called from perf_release since
1900 * that only calls us on the top-level context, which can't be a clone.
1901 * When called from perf_event_exit_task, it's OK because the
1902 * context has been detached from its task.
1904 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1906 struct perf_event_context *ctx = event->ctx;
1908 lockdep_assert_held(&ctx->mutex);
1910 event_function_call(event, __perf_remove_from_context, (void *)flags);
1913 * The above event_function_call() can NO-OP when it hits
1914 * TASK_TOMBSTONE. In that case we must already have been detached
1915 * from the context (by perf_event_exit_event()) but the grouping
1916 * might still be in-tact.
1918 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1919 if ((flags & DETACH_GROUP) &&
1920 (event->attach_state & PERF_ATTACH_GROUP)) {
1922 * Since in that case we cannot possibly be scheduled, simply
1925 raw_spin_lock_irq(&ctx->lock);
1926 perf_group_detach(event);
1927 raw_spin_unlock_irq(&ctx->lock);
1932 * Cross CPU call to disable a performance event
1934 static void __perf_event_disable(struct perf_event *event,
1935 struct perf_cpu_context *cpuctx,
1936 struct perf_event_context *ctx,
1939 if (event->state < PERF_EVENT_STATE_INACTIVE)
1942 update_context_time(ctx);
1943 update_cgrp_time_from_event(event);
1944 update_group_times(event);
1945 if (event == event->group_leader)
1946 group_sched_out(event, cpuctx, ctx);
1948 event_sched_out(event, cpuctx, ctx);
1949 event->state = PERF_EVENT_STATE_OFF;
1955 * If event->ctx is a cloned context, callers must make sure that
1956 * every task struct that event->ctx->task could possibly point to
1957 * remains valid. This condition is satisifed when called through
1958 * perf_event_for_each_child or perf_event_for_each because they
1959 * hold the top-level event's child_mutex, so any descendant that
1960 * goes to exit will block in perf_event_exit_event().
1962 * When called from perf_pending_event it's OK because event->ctx
1963 * is the current context on this CPU and preemption is disabled,
1964 * hence we can't get into perf_event_task_sched_out for this context.
1966 static void _perf_event_disable(struct perf_event *event)
1968 struct perf_event_context *ctx = event->ctx;
1970 raw_spin_lock_irq(&ctx->lock);
1971 if (event->state <= PERF_EVENT_STATE_OFF) {
1972 raw_spin_unlock_irq(&ctx->lock);
1975 raw_spin_unlock_irq(&ctx->lock);
1977 event_function_call(event, __perf_event_disable, NULL);
1980 void perf_event_disable_local(struct perf_event *event)
1982 event_function_local(event, __perf_event_disable, NULL);
1986 * Strictly speaking kernel users cannot create groups and therefore this
1987 * interface does not need the perf_event_ctx_lock() magic.
1989 void perf_event_disable(struct perf_event *event)
1991 struct perf_event_context *ctx;
1993 ctx = perf_event_ctx_lock(event);
1994 _perf_event_disable(event);
1995 perf_event_ctx_unlock(event, ctx);
1997 EXPORT_SYMBOL_GPL(perf_event_disable);
1999 void perf_event_disable_inatomic(struct perf_event *event)
2001 event->pending_disable = 1;
2002 irq_work_queue(&event->pending);
2005 static void perf_set_shadow_time(struct perf_event *event,
2006 struct perf_event_context *ctx,
2010 * use the correct time source for the time snapshot
2012 * We could get by without this by leveraging the
2013 * fact that to get to this function, the caller
2014 * has most likely already called update_context_time()
2015 * and update_cgrp_time_xx() and thus both timestamp
2016 * are identical (or very close). Given that tstamp is,
2017 * already adjusted for cgroup, we could say that:
2018 * tstamp - ctx->timestamp
2020 * tstamp - cgrp->timestamp.
2022 * Then, in perf_output_read(), the calculation would
2023 * work with no changes because:
2024 * - event is guaranteed scheduled in
2025 * - no scheduled out in between
2026 * - thus the timestamp would be the same
2028 * But this is a bit hairy.
2030 * So instead, we have an explicit cgroup call to remain
2031 * within the time time source all along. We believe it
2032 * is cleaner and simpler to understand.
2034 if (is_cgroup_event(event))
2035 perf_cgroup_set_shadow_time(event, tstamp);
2037 event->shadow_ctx_time = tstamp - ctx->timestamp;
2040 #define MAX_INTERRUPTS (~0ULL)
2042 static void perf_log_throttle(struct perf_event *event, int enable);
2043 static void perf_log_itrace_start(struct perf_event *event);
2046 event_sched_in(struct perf_event *event,
2047 struct perf_cpu_context *cpuctx,
2048 struct perf_event_context *ctx)
2050 u64 tstamp = perf_event_time(event);
2053 lockdep_assert_held(&ctx->lock);
2055 if (event->state <= PERF_EVENT_STATE_OFF)
2058 WRITE_ONCE(event->oncpu, smp_processor_id());
2060 * Order event::oncpu write to happen before the ACTIVE state
2064 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2067 * Unthrottle events, since we scheduled we might have missed several
2068 * ticks already, also for a heavily scheduling task there is little
2069 * guarantee it'll get a tick in a timely manner.
2071 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2072 perf_log_throttle(event, 1);
2073 event->hw.interrupts = 0;
2077 * The new state must be visible before we turn it on in the hardware:
2081 perf_pmu_disable(event->pmu);
2083 perf_set_shadow_time(event, ctx, tstamp);
2085 perf_log_itrace_start(event);
2087 if (event->pmu->add(event, PERF_EF_START)) {
2088 event->state = PERF_EVENT_STATE_INACTIVE;
2094 event->tstamp_running += tstamp - event->tstamp_stopped;
2096 if (!is_software_event(event))
2097 cpuctx->active_oncpu++;
2098 if (!ctx->nr_active++)
2099 perf_event_ctx_activate(ctx);
2100 if (event->attr.freq && event->attr.sample_freq)
2103 if (event->attr.exclusive)
2104 cpuctx->exclusive = 1;
2107 perf_pmu_enable(event->pmu);
2113 group_sched_in(struct perf_event *group_event,
2114 struct perf_cpu_context *cpuctx,
2115 struct perf_event_context *ctx)
2117 struct perf_event *event, *partial_group = NULL;
2118 struct pmu *pmu = ctx->pmu;
2119 u64 now = ctx->time;
2120 bool simulate = false;
2122 if (group_event->state == PERF_EVENT_STATE_OFF)
2125 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2127 if (event_sched_in(group_event, cpuctx, ctx)) {
2128 pmu->cancel_txn(pmu);
2129 perf_mux_hrtimer_restart(cpuctx);
2134 * Schedule in siblings as one group (if any):
2136 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2137 if (event_sched_in(event, cpuctx, ctx)) {
2138 partial_group = event;
2143 if (!pmu->commit_txn(pmu))
2148 * Groups can be scheduled in as one unit only, so undo any
2149 * partial group before returning:
2150 * The events up to the failed event are scheduled out normally,
2151 * tstamp_stopped will be updated.
2153 * The failed events and the remaining siblings need to have
2154 * their timings updated as if they had gone thru event_sched_in()
2155 * and event_sched_out(). This is required to get consistent timings
2156 * across the group. This also takes care of the case where the group
2157 * could never be scheduled by ensuring tstamp_stopped is set to mark
2158 * the time the event was actually stopped, such that time delta
2159 * calculation in update_event_times() is correct.
2161 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2162 if (event == partial_group)
2166 event->tstamp_running += now - event->tstamp_stopped;
2167 event->tstamp_stopped = now;
2169 event_sched_out(event, cpuctx, ctx);
2172 event_sched_out(group_event, cpuctx, ctx);
2174 pmu->cancel_txn(pmu);
2176 perf_mux_hrtimer_restart(cpuctx);
2182 * Work out whether we can put this event group on the CPU now.
2184 static int group_can_go_on(struct perf_event *event,
2185 struct perf_cpu_context *cpuctx,
2189 * Groups consisting entirely of software events can always go on.
2191 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2194 * If an exclusive group is already on, no other hardware
2197 if (cpuctx->exclusive)
2200 * If this group is exclusive and there are already
2201 * events on the CPU, it can't go on.
2203 if (event->attr.exclusive && cpuctx->active_oncpu)
2206 * Otherwise, try to add it if all previous groups were able
2212 static void add_event_to_ctx(struct perf_event *event,
2213 struct perf_event_context *ctx)
2215 u64 tstamp = perf_event_time(event);
2217 list_add_event(event, ctx);
2218 perf_group_attach(event);
2219 event->tstamp_enabled = tstamp;
2220 event->tstamp_running = tstamp;
2221 event->tstamp_stopped = tstamp;
2224 static void ctx_sched_out(struct perf_event_context *ctx,
2225 struct perf_cpu_context *cpuctx,
2226 enum event_type_t event_type);
2228 ctx_sched_in(struct perf_event_context *ctx,
2229 struct perf_cpu_context *cpuctx,
2230 enum event_type_t event_type,
2231 struct task_struct *task);
2233 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2234 struct perf_event_context *ctx,
2235 enum event_type_t event_type)
2237 if (!cpuctx->task_ctx)
2240 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2243 ctx_sched_out(ctx, cpuctx, event_type);
2246 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2247 struct perf_event_context *ctx,
2248 struct task_struct *task)
2250 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2252 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2253 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2255 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2259 * We want to maintain the following priority of scheduling:
2260 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2261 * - task pinned (EVENT_PINNED)
2262 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2263 * - task flexible (EVENT_FLEXIBLE).
2265 * In order to avoid unscheduling and scheduling back in everything every
2266 * time an event is added, only do it for the groups of equal priority and
2269 * This can be called after a batch operation on task events, in which case
2270 * event_type is a bit mask of the types of events involved. For CPU events,
2271 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2273 static void ctx_resched(struct perf_cpu_context *cpuctx,
2274 struct perf_event_context *task_ctx,
2275 enum event_type_t event_type)
2277 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2278 bool cpu_event = !!(event_type & EVENT_CPU);
2281 * If pinned groups are involved, flexible groups also need to be
2284 if (event_type & EVENT_PINNED)
2285 event_type |= EVENT_FLEXIBLE;
2287 perf_pmu_disable(cpuctx->ctx.pmu);
2289 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2292 * Decide which cpu ctx groups to schedule out based on the types
2293 * of events that caused rescheduling:
2294 * - EVENT_CPU: schedule out corresponding groups;
2295 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2296 * - otherwise, do nothing more.
2299 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2300 else if (ctx_event_type & EVENT_PINNED)
2301 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2303 perf_event_sched_in(cpuctx, task_ctx, current);
2304 perf_pmu_enable(cpuctx->ctx.pmu);
2308 * Cross CPU call to install and enable a performance event
2310 * Very similar to remote_function() + event_function() but cannot assume that
2311 * things like ctx->is_active and cpuctx->task_ctx are set.
2313 static int __perf_install_in_context(void *info)
2315 struct perf_event *event = info;
2316 struct perf_event_context *ctx = event->ctx;
2317 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2318 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2319 bool reprogram = true;
2322 raw_spin_lock(&cpuctx->ctx.lock);
2324 raw_spin_lock(&ctx->lock);
2327 reprogram = (ctx->task == current);
2330 * If the task is running, it must be running on this CPU,
2331 * otherwise we cannot reprogram things.
2333 * If its not running, we don't care, ctx->lock will
2334 * serialize against it becoming runnable.
2336 if (task_curr(ctx->task) && !reprogram) {
2341 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2342 } else if (task_ctx) {
2343 raw_spin_lock(&task_ctx->lock);
2347 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2348 add_event_to_ctx(event, ctx);
2349 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2351 add_event_to_ctx(event, ctx);
2355 perf_ctx_unlock(cpuctx, task_ctx);
2361 * Attach a performance event to a context.
2363 * Very similar to event_function_call, see comment there.
2366 perf_install_in_context(struct perf_event_context *ctx,
2367 struct perf_event *event,
2370 struct task_struct *task = READ_ONCE(ctx->task);
2372 lockdep_assert_held(&ctx->mutex);
2374 if (event->cpu != -1)
2378 * Ensures that if we can observe event->ctx, both the event and ctx
2379 * will be 'complete'. See perf_iterate_sb_cpu().
2381 smp_store_release(&event->ctx, ctx);
2384 cpu_function_call(cpu, __perf_install_in_context, event);
2389 * Should not happen, we validate the ctx is still alive before calling.
2391 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2395 * Installing events is tricky because we cannot rely on ctx->is_active
2396 * to be set in case this is the nr_events 0 -> 1 transition.
2398 * Instead we use task_curr(), which tells us if the task is running.
2399 * However, since we use task_curr() outside of rq::lock, we can race
2400 * against the actual state. This means the result can be wrong.
2402 * If we get a false positive, we retry, this is harmless.
2404 * If we get a false negative, things are complicated. If we are after
2405 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2406 * value must be correct. If we're before, it doesn't matter since
2407 * perf_event_context_sched_in() will program the counter.
2409 * However, this hinges on the remote context switch having observed
2410 * our task->perf_event_ctxp[] store, such that it will in fact take
2411 * ctx::lock in perf_event_context_sched_in().
2413 * We do this by task_function_call(), if the IPI fails to hit the task
2414 * we know any future context switch of task must see the
2415 * perf_event_ctpx[] store.
2419 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2420 * task_cpu() load, such that if the IPI then does not find the task
2421 * running, a future context switch of that task must observe the
2426 if (!task_function_call(task, __perf_install_in_context, event))
2429 raw_spin_lock_irq(&ctx->lock);
2431 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2433 * Cannot happen because we already checked above (which also
2434 * cannot happen), and we hold ctx->mutex, which serializes us
2435 * against perf_event_exit_task_context().
2437 raw_spin_unlock_irq(&ctx->lock);
2441 * If the task is not running, ctx->lock will avoid it becoming so,
2442 * thus we can safely install the event.
2444 if (task_curr(task)) {
2445 raw_spin_unlock_irq(&ctx->lock);
2448 add_event_to_ctx(event, ctx);
2449 raw_spin_unlock_irq(&ctx->lock);
2453 * Put a event into inactive state and update time fields.
2454 * Enabling the leader of a group effectively enables all
2455 * the group members that aren't explicitly disabled, so we
2456 * have to update their ->tstamp_enabled also.
2457 * Note: this works for group members as well as group leaders
2458 * since the non-leader members' sibling_lists will be empty.
2460 static void __perf_event_mark_enabled(struct perf_event *event)
2462 struct perf_event *sub;
2463 u64 tstamp = perf_event_time(event);
2465 event->state = PERF_EVENT_STATE_INACTIVE;
2466 event->tstamp_enabled = tstamp - event->total_time_enabled;
2467 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2468 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2469 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2474 * Cross CPU call to enable a performance event
2476 static void __perf_event_enable(struct perf_event *event,
2477 struct perf_cpu_context *cpuctx,
2478 struct perf_event_context *ctx,
2481 struct perf_event *leader = event->group_leader;
2482 struct perf_event_context *task_ctx;
2484 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2485 event->state <= PERF_EVENT_STATE_ERROR)
2489 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2491 __perf_event_mark_enabled(event);
2493 if (!ctx->is_active)
2496 if (!event_filter_match(event)) {
2497 if (is_cgroup_event(event))
2498 perf_cgroup_defer_enabled(event);
2499 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2504 * If the event is in a group and isn't the group leader,
2505 * then don't put it on unless the group is on.
2507 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2508 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2512 task_ctx = cpuctx->task_ctx;
2514 WARN_ON_ONCE(task_ctx != ctx);
2516 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2522 * If event->ctx is a cloned context, callers must make sure that
2523 * every task struct that event->ctx->task could possibly point to
2524 * remains valid. This condition is satisfied when called through
2525 * perf_event_for_each_child or perf_event_for_each as described
2526 * for perf_event_disable.
2528 static void _perf_event_enable(struct perf_event *event)
2530 struct perf_event_context *ctx = event->ctx;
2532 raw_spin_lock_irq(&ctx->lock);
2533 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2534 event->state < PERF_EVENT_STATE_ERROR) {
2535 raw_spin_unlock_irq(&ctx->lock);
2540 * If the event is in error state, clear that first.
2542 * That way, if we see the event in error state below, we know that it
2543 * has gone back into error state, as distinct from the task having
2544 * been scheduled away before the cross-call arrived.
2546 if (event->state == PERF_EVENT_STATE_ERROR)
2547 event->state = PERF_EVENT_STATE_OFF;
2548 raw_spin_unlock_irq(&ctx->lock);
2550 event_function_call(event, __perf_event_enable, NULL);
2554 * See perf_event_disable();
2556 void perf_event_enable(struct perf_event *event)
2558 struct perf_event_context *ctx;
2560 ctx = perf_event_ctx_lock(event);
2561 _perf_event_enable(event);
2562 perf_event_ctx_unlock(event, ctx);
2564 EXPORT_SYMBOL_GPL(perf_event_enable);
2566 struct stop_event_data {
2567 struct perf_event *event;
2568 unsigned int restart;
2571 static int __perf_event_stop(void *info)
2573 struct stop_event_data *sd = info;
2574 struct perf_event *event = sd->event;
2576 /* if it's already INACTIVE, do nothing */
2577 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2580 /* matches smp_wmb() in event_sched_in() */
2584 * There is a window with interrupts enabled before we get here,
2585 * so we need to check again lest we try to stop another CPU's event.
2587 if (READ_ONCE(event->oncpu) != smp_processor_id())
2590 event->pmu->stop(event, PERF_EF_UPDATE);
2593 * May race with the actual stop (through perf_pmu_output_stop()),
2594 * but it is only used for events with AUX ring buffer, and such
2595 * events will refuse to restart because of rb::aux_mmap_count==0,
2596 * see comments in perf_aux_output_begin().
2598 * Since this is happening on a event-local CPU, no trace is lost
2602 event->pmu->start(event, 0);
2607 static int perf_event_stop(struct perf_event *event, int restart)
2609 struct stop_event_data sd = {
2616 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2619 /* matches smp_wmb() in event_sched_in() */
2623 * We only want to restart ACTIVE events, so if the event goes
2624 * inactive here (event->oncpu==-1), there's nothing more to do;
2625 * fall through with ret==-ENXIO.
2627 ret = cpu_function_call(READ_ONCE(event->oncpu),
2628 __perf_event_stop, &sd);
2629 } while (ret == -EAGAIN);
2635 * In order to contain the amount of racy and tricky in the address filter
2636 * configuration management, it is a two part process:
2638 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2639 * we update the addresses of corresponding vmas in
2640 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2641 * (p2) when an event is scheduled in (pmu::add), it calls
2642 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2643 * if the generation has changed since the previous call.
2645 * If (p1) happens while the event is active, we restart it to force (p2).
2647 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2648 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2650 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2651 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2653 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2656 void perf_event_addr_filters_sync(struct perf_event *event)
2658 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2660 if (!has_addr_filter(event))
2663 raw_spin_lock(&ifh->lock);
2664 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2665 event->pmu->addr_filters_sync(event);
2666 event->hw.addr_filters_gen = event->addr_filters_gen;
2668 raw_spin_unlock(&ifh->lock);
2670 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2672 static int _perf_event_refresh(struct perf_event *event, int refresh)
2675 * not supported on inherited events
2677 if (event->attr.inherit || !is_sampling_event(event))
2680 atomic_add(refresh, &event->event_limit);
2681 _perf_event_enable(event);
2687 * See perf_event_disable()
2689 int perf_event_refresh(struct perf_event *event, int refresh)
2691 struct perf_event_context *ctx;
2694 ctx = perf_event_ctx_lock(event);
2695 ret = _perf_event_refresh(event, refresh);
2696 perf_event_ctx_unlock(event, ctx);
2700 EXPORT_SYMBOL_GPL(perf_event_refresh);
2702 static void ctx_sched_out(struct perf_event_context *ctx,
2703 struct perf_cpu_context *cpuctx,
2704 enum event_type_t event_type)
2706 int is_active = ctx->is_active;
2707 struct perf_event *event;
2709 lockdep_assert_held(&ctx->lock);
2711 if (likely(!ctx->nr_events)) {
2713 * See __perf_remove_from_context().
2715 WARN_ON_ONCE(ctx->is_active);
2717 WARN_ON_ONCE(cpuctx->task_ctx);
2721 ctx->is_active &= ~event_type;
2722 if (!(ctx->is_active & EVENT_ALL))
2726 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2727 if (!ctx->is_active)
2728 cpuctx->task_ctx = NULL;
2732 * Always update time if it was set; not only when it changes.
2733 * Otherwise we can 'forget' to update time for any but the last
2734 * context we sched out. For example:
2736 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2737 * ctx_sched_out(.event_type = EVENT_PINNED)
2739 * would only update time for the pinned events.
2741 if (is_active & EVENT_TIME) {
2742 /* update (and stop) ctx time */
2743 update_context_time(ctx);
2744 update_cgrp_time_from_cpuctx(cpuctx);
2747 is_active ^= ctx->is_active; /* changed bits */
2749 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2752 perf_pmu_disable(ctx->pmu);
2753 if (is_active & EVENT_PINNED) {
2754 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2755 group_sched_out(event, cpuctx, ctx);
2758 if (is_active & EVENT_FLEXIBLE) {
2759 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2760 group_sched_out(event, cpuctx, ctx);
2762 perf_pmu_enable(ctx->pmu);
2766 * Test whether two contexts are equivalent, i.e. whether they have both been
2767 * cloned from the same version of the same context.
2769 * Equivalence is measured using a generation number in the context that is
2770 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2771 * and list_del_event().
2773 static int context_equiv(struct perf_event_context *ctx1,
2774 struct perf_event_context *ctx2)
2776 lockdep_assert_held(&ctx1->lock);
2777 lockdep_assert_held(&ctx2->lock);
2779 /* Pinning disables the swap optimization */
2780 if (ctx1->pin_count || ctx2->pin_count)
2783 /* If ctx1 is the parent of ctx2 */
2784 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2787 /* If ctx2 is the parent of ctx1 */
2788 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2792 * If ctx1 and ctx2 have the same parent; we flatten the parent
2793 * hierarchy, see perf_event_init_context().
2795 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2796 ctx1->parent_gen == ctx2->parent_gen)
2803 static void __perf_event_sync_stat(struct perf_event *event,
2804 struct perf_event *next_event)
2808 if (!event->attr.inherit_stat)
2812 * Update the event value, we cannot use perf_event_read()
2813 * because we're in the middle of a context switch and have IRQs
2814 * disabled, which upsets smp_call_function_single(), however
2815 * we know the event must be on the current CPU, therefore we
2816 * don't need to use it.
2818 switch (event->state) {
2819 case PERF_EVENT_STATE_ACTIVE:
2820 event->pmu->read(event);
2823 case PERF_EVENT_STATE_INACTIVE:
2824 update_event_times(event);
2832 * In order to keep per-task stats reliable we need to flip the event
2833 * values when we flip the contexts.
2835 value = local64_read(&next_event->count);
2836 value = local64_xchg(&event->count, value);
2837 local64_set(&next_event->count, value);
2839 swap(event->total_time_enabled, next_event->total_time_enabled);
2840 swap(event->total_time_running, next_event->total_time_running);
2843 * Since we swizzled the values, update the user visible data too.
2845 perf_event_update_userpage(event);
2846 perf_event_update_userpage(next_event);
2849 static void perf_event_sync_stat(struct perf_event_context *ctx,
2850 struct perf_event_context *next_ctx)
2852 struct perf_event *event, *next_event;
2857 update_context_time(ctx);
2859 event = list_first_entry(&ctx->event_list,
2860 struct perf_event, event_entry);
2862 next_event = list_first_entry(&next_ctx->event_list,
2863 struct perf_event, event_entry);
2865 while (&event->event_entry != &ctx->event_list &&
2866 &next_event->event_entry != &next_ctx->event_list) {
2868 __perf_event_sync_stat(event, next_event);
2870 event = list_next_entry(event, event_entry);
2871 next_event = list_next_entry(next_event, event_entry);
2875 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2876 struct task_struct *next)
2878 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2879 struct perf_event_context *next_ctx;
2880 struct perf_event_context *parent, *next_parent;
2881 struct perf_cpu_context *cpuctx;
2887 cpuctx = __get_cpu_context(ctx);
2888 if (!cpuctx->task_ctx)
2892 next_ctx = next->perf_event_ctxp[ctxn];
2896 parent = rcu_dereference(ctx->parent_ctx);
2897 next_parent = rcu_dereference(next_ctx->parent_ctx);
2899 /* If neither context have a parent context; they cannot be clones. */
2900 if (!parent && !next_parent)
2903 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2905 * Looks like the two contexts are clones, so we might be
2906 * able to optimize the context switch. We lock both
2907 * contexts and check that they are clones under the
2908 * lock (including re-checking that neither has been
2909 * uncloned in the meantime). It doesn't matter which
2910 * order we take the locks because no other cpu could
2911 * be trying to lock both of these tasks.
2913 raw_spin_lock(&ctx->lock);
2914 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2915 if (context_equiv(ctx, next_ctx)) {
2916 WRITE_ONCE(ctx->task, next);
2917 WRITE_ONCE(next_ctx->task, task);
2919 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2922 * RCU_INIT_POINTER here is safe because we've not
2923 * modified the ctx and the above modification of
2924 * ctx->task and ctx->task_ctx_data are immaterial
2925 * since those values are always verified under
2926 * ctx->lock which we're now holding.
2928 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2929 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2933 perf_event_sync_stat(ctx, next_ctx);
2935 raw_spin_unlock(&next_ctx->lock);
2936 raw_spin_unlock(&ctx->lock);
2942 raw_spin_lock(&ctx->lock);
2943 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2944 raw_spin_unlock(&ctx->lock);
2948 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2950 void perf_sched_cb_dec(struct pmu *pmu)
2952 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2954 this_cpu_dec(perf_sched_cb_usages);
2956 if (!--cpuctx->sched_cb_usage)
2957 list_del(&cpuctx->sched_cb_entry);
2961 void perf_sched_cb_inc(struct pmu *pmu)
2963 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2965 if (!cpuctx->sched_cb_usage++)
2966 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2968 this_cpu_inc(perf_sched_cb_usages);
2972 * This function provides the context switch callback to the lower code
2973 * layer. It is invoked ONLY when the context switch callback is enabled.
2975 * This callback is relevant even to per-cpu events; for example multi event
2976 * PEBS requires this to provide PID/TID information. This requires we flush
2977 * all queued PEBS records before we context switch to a new task.
2979 static void perf_pmu_sched_task(struct task_struct *prev,
2980 struct task_struct *next,
2983 struct perf_cpu_context *cpuctx;
2989 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2990 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
2992 if (WARN_ON_ONCE(!pmu->sched_task))
2995 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2996 perf_pmu_disable(pmu);
2998 pmu->sched_task(cpuctx->task_ctx, sched_in);
3000 perf_pmu_enable(pmu);
3001 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3005 static void perf_event_switch(struct task_struct *task,
3006 struct task_struct *next_prev, bool sched_in);
3008 #define for_each_task_context_nr(ctxn) \
3009 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3012 * Called from scheduler to remove the events of the current task,
3013 * with interrupts disabled.
3015 * We stop each event and update the event value in event->count.
3017 * This does not protect us against NMI, but disable()
3018 * sets the disabled bit in the control field of event _before_
3019 * accessing the event control register. If a NMI hits, then it will
3020 * not restart the event.
3022 void __perf_event_task_sched_out(struct task_struct *task,
3023 struct task_struct *next)
3027 if (__this_cpu_read(perf_sched_cb_usages))
3028 perf_pmu_sched_task(task, next, false);
3030 if (atomic_read(&nr_switch_events))
3031 perf_event_switch(task, next, false);
3033 for_each_task_context_nr(ctxn)
3034 perf_event_context_sched_out(task, ctxn, next);
3037 * if cgroup events exist on this CPU, then we need
3038 * to check if we have to switch out PMU state.
3039 * cgroup event are system-wide mode only
3041 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3042 perf_cgroup_sched_out(task, next);
3046 * Called with IRQs disabled
3048 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3049 enum event_type_t event_type)
3051 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3055 ctx_pinned_sched_in(struct perf_event_context *ctx,
3056 struct perf_cpu_context *cpuctx)
3058 struct perf_event *event;
3060 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3061 if (event->state <= PERF_EVENT_STATE_OFF)
3063 if (!event_filter_match(event))
3066 /* may need to reset tstamp_enabled */
3067 if (is_cgroup_event(event))
3068 perf_cgroup_mark_enabled(event, ctx);
3070 if (group_can_go_on(event, cpuctx, 1))
3071 group_sched_in(event, cpuctx, ctx);
3074 * If this pinned group hasn't been scheduled,
3075 * put it in error state.
3077 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3078 update_group_times(event);
3079 event->state = PERF_EVENT_STATE_ERROR;
3085 ctx_flexible_sched_in(struct perf_event_context *ctx,
3086 struct perf_cpu_context *cpuctx)
3088 struct perf_event *event;
3091 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3092 /* Ignore events in OFF or ERROR state */
3093 if (event->state <= PERF_EVENT_STATE_OFF)
3096 * Listen to the 'cpu' scheduling filter constraint
3099 if (!event_filter_match(event))
3102 /* may need to reset tstamp_enabled */
3103 if (is_cgroup_event(event))
3104 perf_cgroup_mark_enabled(event, ctx);
3106 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3107 if (group_sched_in(event, cpuctx, ctx))
3114 ctx_sched_in(struct perf_event_context *ctx,
3115 struct perf_cpu_context *cpuctx,
3116 enum event_type_t event_type,
3117 struct task_struct *task)
3119 int is_active = ctx->is_active;
3122 lockdep_assert_held(&ctx->lock);
3124 if (likely(!ctx->nr_events))
3127 ctx->is_active |= (event_type | EVENT_TIME);
3130 cpuctx->task_ctx = ctx;
3132 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3135 is_active ^= ctx->is_active; /* changed bits */
3137 if (is_active & EVENT_TIME) {
3138 /* start ctx time */
3140 ctx->timestamp = now;
3141 perf_cgroup_set_timestamp(task, ctx);
3145 * First go through the list and put on any pinned groups
3146 * in order to give them the best chance of going on.
3148 if (is_active & EVENT_PINNED)
3149 ctx_pinned_sched_in(ctx, cpuctx);
3151 /* Then walk through the lower prio flexible groups */
3152 if (is_active & EVENT_FLEXIBLE)
3153 ctx_flexible_sched_in(ctx, cpuctx);
3156 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3157 enum event_type_t event_type,
3158 struct task_struct *task)
3160 struct perf_event_context *ctx = &cpuctx->ctx;
3162 ctx_sched_in(ctx, cpuctx, event_type, task);
3165 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3166 struct task_struct *task)
3168 struct perf_cpu_context *cpuctx;
3170 cpuctx = __get_cpu_context(ctx);
3171 if (cpuctx->task_ctx == ctx)
3174 perf_ctx_lock(cpuctx, ctx);
3175 perf_pmu_disable(ctx->pmu);
3177 * We want to keep the following priority order:
3178 * cpu pinned (that don't need to move), task pinned,
3179 * cpu flexible, task flexible.
3181 * However, if task's ctx is not carrying any pinned
3182 * events, no need to flip the cpuctx's events around.
3184 if (!list_empty(&ctx->pinned_groups))
3185 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3186 perf_event_sched_in(cpuctx, ctx, task);
3187 perf_pmu_enable(ctx->pmu);
3188 perf_ctx_unlock(cpuctx, ctx);
3192 * Called from scheduler to add the events of the current task
3193 * with interrupts disabled.
3195 * We restore the event value and then enable it.
3197 * This does not protect us against NMI, but enable()
3198 * sets the enabled bit in the control field of event _before_
3199 * accessing the event control register. If a NMI hits, then it will
3200 * keep the event running.
3202 void __perf_event_task_sched_in(struct task_struct *prev,
3203 struct task_struct *task)
3205 struct perf_event_context *ctx;
3209 * If cgroup events exist on this CPU, then we need to check if we have
3210 * to switch in PMU state; cgroup event are system-wide mode only.
3212 * Since cgroup events are CPU events, we must schedule these in before
3213 * we schedule in the task events.
3215 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3216 perf_cgroup_sched_in(prev, task);
3218 for_each_task_context_nr(ctxn) {
3219 ctx = task->perf_event_ctxp[ctxn];
3223 perf_event_context_sched_in(ctx, task);
3226 if (atomic_read(&nr_switch_events))
3227 perf_event_switch(task, prev, true);
3229 if (__this_cpu_read(perf_sched_cb_usages))
3230 perf_pmu_sched_task(prev, task, true);
3233 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3235 u64 frequency = event->attr.sample_freq;
3236 u64 sec = NSEC_PER_SEC;
3237 u64 divisor, dividend;
3239 int count_fls, nsec_fls, frequency_fls, sec_fls;
3241 count_fls = fls64(count);
3242 nsec_fls = fls64(nsec);
3243 frequency_fls = fls64(frequency);
3247 * We got @count in @nsec, with a target of sample_freq HZ
3248 * the target period becomes:
3251 * period = -------------------
3252 * @nsec * sample_freq
3257 * Reduce accuracy by one bit such that @a and @b converge
3258 * to a similar magnitude.
3260 #define REDUCE_FLS(a, b) \
3262 if (a##_fls > b##_fls) { \
3272 * Reduce accuracy until either term fits in a u64, then proceed with
3273 * the other, so that finally we can do a u64/u64 division.
3275 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3276 REDUCE_FLS(nsec, frequency);
3277 REDUCE_FLS(sec, count);
3280 if (count_fls + sec_fls > 64) {
3281 divisor = nsec * frequency;
3283 while (count_fls + sec_fls > 64) {
3284 REDUCE_FLS(count, sec);
3288 dividend = count * sec;
3290 dividend = count * sec;
3292 while (nsec_fls + frequency_fls > 64) {
3293 REDUCE_FLS(nsec, frequency);
3297 divisor = nsec * frequency;
3303 return div64_u64(dividend, divisor);
3306 static DEFINE_PER_CPU(int, perf_throttled_count);
3307 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3309 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3311 struct hw_perf_event *hwc = &event->hw;
3312 s64 period, sample_period;
3315 period = perf_calculate_period(event, nsec, count);
3317 delta = (s64)(period - hwc->sample_period);
3318 delta = (delta + 7) / 8; /* low pass filter */
3320 sample_period = hwc->sample_period + delta;
3325 hwc->sample_period = sample_period;
3327 if (local64_read(&hwc->period_left) > 8*sample_period) {
3329 event->pmu->stop(event, PERF_EF_UPDATE);
3331 local64_set(&hwc->period_left, 0);
3334 event->pmu->start(event, PERF_EF_RELOAD);
3339 * combine freq adjustment with unthrottling to avoid two passes over the
3340 * events. At the same time, make sure, having freq events does not change
3341 * the rate of unthrottling as that would introduce bias.
3343 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3346 struct perf_event *event;
3347 struct hw_perf_event *hwc;
3348 u64 now, period = TICK_NSEC;
3352 * only need to iterate over all events iff:
3353 * - context have events in frequency mode (needs freq adjust)
3354 * - there are events to unthrottle on this cpu
3356 if (!(ctx->nr_freq || needs_unthr))
3359 raw_spin_lock(&ctx->lock);
3360 perf_pmu_disable(ctx->pmu);
3362 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3363 if (event->state != PERF_EVENT_STATE_ACTIVE)
3366 if (!event_filter_match(event))
3369 perf_pmu_disable(event->pmu);
3373 if (hwc->interrupts == MAX_INTERRUPTS) {
3374 hwc->interrupts = 0;
3375 perf_log_throttle(event, 1);
3376 event->pmu->start(event, 0);
3379 if (!event->attr.freq || !event->attr.sample_freq)
3383 * stop the event and update event->count
3385 event->pmu->stop(event, PERF_EF_UPDATE);
3387 now = local64_read(&event->count);
3388 delta = now - hwc->freq_count_stamp;
3389 hwc->freq_count_stamp = now;
3393 * reload only if value has changed
3394 * we have stopped the event so tell that
3395 * to perf_adjust_period() to avoid stopping it
3399 perf_adjust_period(event, period, delta, false);
3401 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3403 perf_pmu_enable(event->pmu);
3406 perf_pmu_enable(ctx->pmu);
3407 raw_spin_unlock(&ctx->lock);
3411 * Round-robin a context's events:
3413 static void rotate_ctx(struct perf_event_context *ctx)
3416 * Rotate the first entry last of non-pinned groups. Rotation might be
3417 * disabled by the inheritance code.
3419 if (!ctx->rotate_disable)
3420 list_rotate_left(&ctx->flexible_groups);
3423 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3425 struct perf_event_context *ctx = NULL;
3428 if (cpuctx->ctx.nr_events) {
3429 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3433 ctx = cpuctx->task_ctx;
3434 if (ctx && ctx->nr_events) {
3435 if (ctx->nr_events != ctx->nr_active)
3442 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3443 perf_pmu_disable(cpuctx->ctx.pmu);
3445 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3447 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3449 rotate_ctx(&cpuctx->ctx);
3453 perf_event_sched_in(cpuctx, ctx, current);
3455 perf_pmu_enable(cpuctx->ctx.pmu);
3456 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3462 void perf_event_task_tick(void)
3464 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3465 struct perf_event_context *ctx, *tmp;
3468 WARN_ON(!irqs_disabled());
3470 __this_cpu_inc(perf_throttled_seq);
3471 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3472 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3474 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3475 perf_adjust_freq_unthr_context(ctx, throttled);
3478 static int event_enable_on_exec(struct perf_event *event,
3479 struct perf_event_context *ctx)
3481 if (!event->attr.enable_on_exec)
3484 event->attr.enable_on_exec = 0;
3485 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3488 __perf_event_mark_enabled(event);
3494 * Enable all of a task's events that have been marked enable-on-exec.
3495 * This expects task == current.
3497 static void perf_event_enable_on_exec(int ctxn)
3499 struct perf_event_context *ctx, *clone_ctx = NULL;
3500 enum event_type_t event_type = 0;
3501 struct perf_cpu_context *cpuctx;
3502 struct perf_event *event;
3503 unsigned long flags;
3506 local_irq_save(flags);
3507 ctx = current->perf_event_ctxp[ctxn];
3508 if (!ctx || !ctx->nr_events)
3511 cpuctx = __get_cpu_context(ctx);
3512 perf_ctx_lock(cpuctx, ctx);
3513 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3514 list_for_each_entry(event, &ctx->event_list, event_entry) {
3515 enabled |= event_enable_on_exec(event, ctx);
3516 event_type |= get_event_type(event);
3520 * Unclone and reschedule this context if we enabled any event.
3523 clone_ctx = unclone_ctx(ctx);
3524 ctx_resched(cpuctx, ctx, event_type);
3526 perf_ctx_unlock(cpuctx, ctx);
3529 local_irq_restore(flags);
3535 struct perf_read_data {
3536 struct perf_event *event;
3541 static int find_cpu_to_read(struct perf_event *event, int local_cpu)
3543 int event_cpu = event->oncpu;
3544 u16 local_pkg, event_pkg;
3546 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3547 event_pkg = topology_physical_package_id(event_cpu);
3548 local_pkg = topology_physical_package_id(local_cpu);
3550 if (event_pkg == local_pkg)
3558 * Cross CPU call to read the hardware event
3560 static void __perf_event_read(void *info)
3562 struct perf_read_data *data = info;
3563 struct perf_event *sub, *event = data->event;
3564 struct perf_event_context *ctx = event->ctx;
3565 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3566 struct pmu *pmu = event->pmu;
3569 * If this is a task context, we need to check whether it is
3570 * the current task context of this cpu. If not it has been
3571 * scheduled out before the smp call arrived. In that case
3572 * event->count would have been updated to a recent sample
3573 * when the event was scheduled out.
3575 if (ctx->task && cpuctx->task_ctx != ctx)
3578 raw_spin_lock(&ctx->lock);
3579 if (ctx->is_active) {
3580 update_context_time(ctx);
3581 update_cgrp_time_from_event(event);
3584 update_event_times(event);
3585 if (event->state != PERF_EVENT_STATE_ACTIVE)
3594 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3598 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3599 update_event_times(sub);
3600 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3602 * Use sibling's PMU rather than @event's since
3603 * sibling could be on different (eg: software) PMU.
3605 sub->pmu->read(sub);
3609 data->ret = pmu->commit_txn(pmu);
3612 raw_spin_unlock(&ctx->lock);
3615 static inline u64 perf_event_count(struct perf_event *event)
3617 if (event->pmu->count)
3618 return event->pmu->count(event);
3620 return __perf_event_count(event);
3624 * NMI-safe method to read a local event, that is an event that
3626 * - either for the current task, or for this CPU
3627 * - does not have inherit set, for inherited task events
3628 * will not be local and we cannot read them atomically
3629 * - must not have a pmu::count method
3631 u64 perf_event_read_local(struct perf_event *event)
3633 unsigned long flags;
3637 * Disabling interrupts avoids all counter scheduling (context
3638 * switches, timer based rotation and IPIs).
3640 local_irq_save(flags);
3642 /* If this is a per-task event, it must be for current */
3643 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3644 event->hw.target != current);
3646 /* If this is a per-CPU event, it must be for this CPU */
3647 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3648 event->cpu != smp_processor_id());
3651 * It must not be an event with inherit set, we cannot read
3652 * all child counters from atomic context.
3654 WARN_ON_ONCE(event->attr.inherit);
3657 * It must not have a pmu::count method, those are not
3660 WARN_ON_ONCE(event->pmu->count);
3663 * If the event is currently on this CPU, its either a per-task event,
3664 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3667 if (event->oncpu == smp_processor_id())
3668 event->pmu->read(event);
3670 val = local64_read(&event->count);
3671 local_irq_restore(flags);
3676 static int perf_event_read(struct perf_event *event, bool group)
3678 int ret = 0, cpu_to_read, local_cpu;
3681 * If event is enabled and currently active on a CPU, update the
3682 * value in the event structure:
3684 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3685 struct perf_read_data data = {
3691 local_cpu = get_cpu();
3692 cpu_to_read = find_cpu_to_read(event, local_cpu);
3696 * Purposely ignore the smp_call_function_single() return
3699 * If event->oncpu isn't a valid CPU it means the event got
3700 * scheduled out and that will have updated the event count.
3702 * Therefore, either way, we'll have an up-to-date event count
3705 (void)smp_call_function_single(cpu_to_read, __perf_event_read, &data, 1);
3707 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3708 struct perf_event_context *ctx = event->ctx;
3709 unsigned long flags;
3711 raw_spin_lock_irqsave(&ctx->lock, flags);
3713 * may read while context is not active
3714 * (e.g., thread is blocked), in that case
3715 * we cannot update context time
3717 if (ctx->is_active) {
3718 update_context_time(ctx);
3719 update_cgrp_time_from_event(event);
3722 update_group_times(event);
3724 update_event_times(event);
3725 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3732 * Initialize the perf_event context in a task_struct:
3734 static void __perf_event_init_context(struct perf_event_context *ctx)
3736 raw_spin_lock_init(&ctx->lock);
3737 mutex_init(&ctx->mutex);
3738 INIT_LIST_HEAD(&ctx->active_ctx_list);
3739 INIT_LIST_HEAD(&ctx->pinned_groups);
3740 INIT_LIST_HEAD(&ctx->flexible_groups);
3741 INIT_LIST_HEAD(&ctx->event_list);
3742 atomic_set(&ctx->refcount, 1);
3745 static struct perf_event_context *
3746 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3748 struct perf_event_context *ctx;
3750 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3754 __perf_event_init_context(ctx);
3757 get_task_struct(task);
3764 static struct task_struct *
3765 find_lively_task_by_vpid(pid_t vpid)
3767 struct task_struct *task;
3773 task = find_task_by_vpid(vpid);
3775 get_task_struct(task);
3779 return ERR_PTR(-ESRCH);
3785 * Returns a matching context with refcount and pincount.
3787 static struct perf_event_context *
3788 find_get_context(struct pmu *pmu, struct task_struct *task,
3789 struct perf_event *event)
3791 struct perf_event_context *ctx, *clone_ctx = NULL;
3792 struct perf_cpu_context *cpuctx;
3793 void *task_ctx_data = NULL;
3794 unsigned long flags;
3796 int cpu = event->cpu;
3799 /* Must be root to operate on a CPU event: */
3800 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3801 return ERR_PTR(-EACCES);
3804 * We could be clever and allow to attach a event to an
3805 * offline CPU and activate it when the CPU comes up, but
3808 if (!cpu_online(cpu))
3809 return ERR_PTR(-ENODEV);
3811 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3820 ctxn = pmu->task_ctx_nr;
3824 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3825 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3826 if (!task_ctx_data) {
3833 ctx = perf_lock_task_context(task, ctxn, &flags);
3835 clone_ctx = unclone_ctx(ctx);
3838 if (task_ctx_data && !ctx->task_ctx_data) {
3839 ctx->task_ctx_data = task_ctx_data;
3840 task_ctx_data = NULL;
3842 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3847 ctx = alloc_perf_context(pmu, task);
3852 if (task_ctx_data) {
3853 ctx->task_ctx_data = task_ctx_data;
3854 task_ctx_data = NULL;
3858 mutex_lock(&task->perf_event_mutex);
3860 * If it has already passed perf_event_exit_task().
3861 * we must see PF_EXITING, it takes this mutex too.
3863 if (task->flags & PF_EXITING)
3865 else if (task->perf_event_ctxp[ctxn])
3870 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3872 mutex_unlock(&task->perf_event_mutex);
3874 if (unlikely(err)) {
3883 kfree(task_ctx_data);
3887 kfree(task_ctx_data);
3888 return ERR_PTR(err);
3891 static void perf_event_free_filter(struct perf_event *event);
3892 static void perf_event_free_bpf_prog(struct perf_event *event);
3894 static void free_event_rcu(struct rcu_head *head)
3896 struct perf_event *event;
3898 event = container_of(head, struct perf_event, rcu_head);
3900 put_pid_ns(event->ns);
3901 perf_event_free_filter(event);
3905 static void ring_buffer_attach(struct perf_event *event,
3906 struct ring_buffer *rb);
3908 static void detach_sb_event(struct perf_event *event)
3910 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3912 raw_spin_lock(&pel->lock);
3913 list_del_rcu(&event->sb_list);
3914 raw_spin_unlock(&pel->lock);
3917 static bool is_sb_event(struct perf_event *event)
3919 struct perf_event_attr *attr = &event->attr;
3924 if (event->attach_state & PERF_ATTACH_TASK)
3927 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3928 attr->comm || attr->comm_exec ||
3930 attr->context_switch)
3935 static void unaccount_pmu_sb_event(struct perf_event *event)
3937 if (is_sb_event(event))
3938 detach_sb_event(event);
3941 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3946 if (is_cgroup_event(event))
3947 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3950 #ifdef CONFIG_NO_HZ_FULL
3951 static DEFINE_SPINLOCK(nr_freq_lock);
3954 static void unaccount_freq_event_nohz(void)
3956 #ifdef CONFIG_NO_HZ_FULL
3957 spin_lock(&nr_freq_lock);
3958 if (atomic_dec_and_test(&nr_freq_events))
3959 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3960 spin_unlock(&nr_freq_lock);
3964 static void unaccount_freq_event(void)
3966 if (tick_nohz_full_enabled())
3967 unaccount_freq_event_nohz();
3969 atomic_dec(&nr_freq_events);
3972 static void unaccount_event(struct perf_event *event)
3979 if (event->attach_state & PERF_ATTACH_TASK)
3981 if (event->attr.mmap || event->attr.mmap_data)
3982 atomic_dec(&nr_mmap_events);
3983 if (event->attr.comm)
3984 atomic_dec(&nr_comm_events);
3985 if (event->attr.task)
3986 atomic_dec(&nr_task_events);
3987 if (event->attr.freq)
3988 unaccount_freq_event();
3989 if (event->attr.context_switch) {
3991 atomic_dec(&nr_switch_events);
3993 if (is_cgroup_event(event))
3995 if (has_branch_stack(event))
3999 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4000 schedule_delayed_work(&perf_sched_work, HZ);
4003 unaccount_event_cpu(event, event->cpu);
4005 unaccount_pmu_sb_event(event);
4008 static void perf_sched_delayed(struct work_struct *work)
4010 mutex_lock(&perf_sched_mutex);
4011 if (atomic_dec_and_test(&perf_sched_count))
4012 static_branch_disable(&perf_sched_events);
4013 mutex_unlock(&perf_sched_mutex);
4017 * The following implement mutual exclusion of events on "exclusive" pmus
4018 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4019 * at a time, so we disallow creating events that might conflict, namely:
4021 * 1) cpu-wide events in the presence of per-task events,
4022 * 2) per-task events in the presence of cpu-wide events,
4023 * 3) two matching events on the same context.
4025 * The former two cases are handled in the allocation path (perf_event_alloc(),
4026 * _free_event()), the latter -- before the first perf_install_in_context().
4028 static int exclusive_event_init(struct perf_event *event)
4030 struct pmu *pmu = event->pmu;
4032 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4036 * Prevent co-existence of per-task and cpu-wide events on the
4037 * same exclusive pmu.
4039 * Negative pmu::exclusive_cnt means there are cpu-wide
4040 * events on this "exclusive" pmu, positive means there are
4043 * Since this is called in perf_event_alloc() path, event::ctx
4044 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4045 * to mean "per-task event", because unlike other attach states it
4046 * never gets cleared.
4048 if (event->attach_state & PERF_ATTACH_TASK) {
4049 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4052 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4059 static void exclusive_event_destroy(struct perf_event *event)
4061 struct pmu *pmu = event->pmu;
4063 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4066 /* see comment in exclusive_event_init() */
4067 if (event->attach_state & PERF_ATTACH_TASK)
4068 atomic_dec(&pmu->exclusive_cnt);
4070 atomic_inc(&pmu->exclusive_cnt);
4073 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4075 if ((e1->pmu == e2->pmu) &&
4076 (e1->cpu == e2->cpu ||
4083 /* Called under the same ctx::mutex as perf_install_in_context() */
4084 static bool exclusive_event_installable(struct perf_event *event,
4085 struct perf_event_context *ctx)
4087 struct perf_event *iter_event;
4088 struct pmu *pmu = event->pmu;
4090 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4093 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4094 if (exclusive_event_match(iter_event, event))
4101 static void perf_addr_filters_splice(struct perf_event *event,
4102 struct list_head *head);
4104 static void _free_event(struct perf_event *event)
4106 irq_work_sync(&event->pending);
4108 unaccount_event(event);
4112 * Can happen when we close an event with re-directed output.
4114 * Since we have a 0 refcount, perf_mmap_close() will skip
4115 * over us; possibly making our ring_buffer_put() the last.
4117 mutex_lock(&event->mmap_mutex);
4118 ring_buffer_attach(event, NULL);
4119 mutex_unlock(&event->mmap_mutex);
4122 if (is_cgroup_event(event))
4123 perf_detach_cgroup(event);
4125 if (!event->parent) {
4126 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4127 put_callchain_buffers();
4130 perf_event_free_bpf_prog(event);
4131 perf_addr_filters_splice(event, NULL);
4132 kfree(event->addr_filters_offs);
4135 event->destroy(event);
4138 put_ctx(event->ctx);
4140 exclusive_event_destroy(event);
4141 module_put(event->pmu->module);
4143 call_rcu(&event->rcu_head, free_event_rcu);
4147 * Used to free events which have a known refcount of 1, such as in error paths
4148 * where the event isn't exposed yet and inherited events.
4150 static void free_event(struct perf_event *event)
4152 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4153 "unexpected event refcount: %ld; ptr=%p\n",
4154 atomic_long_read(&event->refcount), event)) {
4155 /* leak to avoid use-after-free */
4163 * Remove user event from the owner task.
4165 static void perf_remove_from_owner(struct perf_event *event)
4167 struct task_struct *owner;
4171 * Matches the smp_store_release() in perf_event_exit_task(). If we
4172 * observe !owner it means the list deletion is complete and we can
4173 * indeed free this event, otherwise we need to serialize on
4174 * owner->perf_event_mutex.
4176 owner = lockless_dereference(event->owner);
4179 * Since delayed_put_task_struct() also drops the last
4180 * task reference we can safely take a new reference
4181 * while holding the rcu_read_lock().
4183 get_task_struct(owner);
4189 * If we're here through perf_event_exit_task() we're already
4190 * holding ctx->mutex which would be an inversion wrt. the
4191 * normal lock order.
4193 * However we can safely take this lock because its the child
4196 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4199 * We have to re-check the event->owner field, if it is cleared
4200 * we raced with perf_event_exit_task(), acquiring the mutex
4201 * ensured they're done, and we can proceed with freeing the
4205 list_del_init(&event->owner_entry);
4206 smp_store_release(&event->owner, NULL);
4208 mutex_unlock(&owner->perf_event_mutex);
4209 put_task_struct(owner);
4213 static void put_event(struct perf_event *event)
4215 if (!atomic_long_dec_and_test(&event->refcount))
4222 * Kill an event dead; while event:refcount will preserve the event
4223 * object, it will not preserve its functionality. Once the last 'user'
4224 * gives up the object, we'll destroy the thing.
4226 int perf_event_release_kernel(struct perf_event *event)
4228 struct perf_event_context *ctx = event->ctx;
4229 struct perf_event *child, *tmp;
4232 * If we got here through err_file: fput(event_file); we will not have
4233 * attached to a context yet.
4236 WARN_ON_ONCE(event->attach_state &
4237 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4241 if (!is_kernel_event(event))
4242 perf_remove_from_owner(event);
4244 ctx = perf_event_ctx_lock(event);
4245 WARN_ON_ONCE(ctx->parent_ctx);
4246 perf_remove_from_context(event, DETACH_GROUP);
4248 raw_spin_lock_irq(&ctx->lock);
4250 * Mark this even as STATE_DEAD, there is no external reference to it
4253 * Anybody acquiring event->child_mutex after the below loop _must_
4254 * also see this, most importantly inherit_event() which will avoid
4255 * placing more children on the list.
4257 * Thus this guarantees that we will in fact observe and kill _ALL_
4260 event->state = PERF_EVENT_STATE_DEAD;
4261 raw_spin_unlock_irq(&ctx->lock);
4263 perf_event_ctx_unlock(event, ctx);
4266 mutex_lock(&event->child_mutex);
4267 list_for_each_entry(child, &event->child_list, child_list) {
4270 * Cannot change, child events are not migrated, see the
4271 * comment with perf_event_ctx_lock_nested().
4273 ctx = lockless_dereference(child->ctx);
4275 * Since child_mutex nests inside ctx::mutex, we must jump
4276 * through hoops. We start by grabbing a reference on the ctx.
4278 * Since the event cannot get freed while we hold the
4279 * child_mutex, the context must also exist and have a !0
4285 * Now that we have a ctx ref, we can drop child_mutex, and
4286 * acquire ctx::mutex without fear of it going away. Then we
4287 * can re-acquire child_mutex.
4289 mutex_unlock(&event->child_mutex);
4290 mutex_lock(&ctx->mutex);
4291 mutex_lock(&event->child_mutex);
4294 * Now that we hold ctx::mutex and child_mutex, revalidate our
4295 * state, if child is still the first entry, it didn't get freed
4296 * and we can continue doing so.
4298 tmp = list_first_entry_or_null(&event->child_list,
4299 struct perf_event, child_list);
4301 perf_remove_from_context(child, DETACH_GROUP);
4302 list_del(&child->child_list);
4305 * This matches the refcount bump in inherit_event();
4306 * this can't be the last reference.
4311 mutex_unlock(&event->child_mutex);
4312 mutex_unlock(&ctx->mutex);
4316 mutex_unlock(&event->child_mutex);
4319 put_event(event); /* Must be the 'last' reference */
4322 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4325 * Called when the last reference to the file is gone.
4327 static int perf_release(struct inode *inode, struct file *file)
4329 perf_event_release_kernel(file->private_data);
4333 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4335 struct perf_event *child;
4341 mutex_lock(&event->child_mutex);
4343 (void)perf_event_read(event, false);
4344 total += perf_event_count(event);
4346 *enabled += event->total_time_enabled +
4347 atomic64_read(&event->child_total_time_enabled);
4348 *running += event->total_time_running +
4349 atomic64_read(&event->child_total_time_running);
4351 list_for_each_entry(child, &event->child_list, child_list) {
4352 (void)perf_event_read(child, false);
4353 total += perf_event_count(child);
4354 *enabled += child->total_time_enabled;
4355 *running += child->total_time_running;
4357 mutex_unlock(&event->child_mutex);
4361 EXPORT_SYMBOL_GPL(perf_event_read_value);
4363 static int __perf_read_group_add(struct perf_event *leader,
4364 u64 read_format, u64 *values)
4366 struct perf_event *sub;
4367 int n = 1; /* skip @nr */
4370 ret = perf_event_read(leader, true);
4375 * Since we co-schedule groups, {enabled,running} times of siblings
4376 * will be identical to those of the leader, so we only publish one
4379 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4380 values[n++] += leader->total_time_enabled +
4381 atomic64_read(&leader->child_total_time_enabled);
4384 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4385 values[n++] += leader->total_time_running +
4386 atomic64_read(&leader->child_total_time_running);
4390 * Write {count,id} tuples for every sibling.
4392 values[n++] += perf_event_count(leader);
4393 if (read_format & PERF_FORMAT_ID)
4394 values[n++] = primary_event_id(leader);
4396 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4397 values[n++] += perf_event_count(sub);
4398 if (read_format & PERF_FORMAT_ID)
4399 values[n++] = primary_event_id(sub);
4405 static int perf_read_group(struct perf_event *event,
4406 u64 read_format, char __user *buf)
4408 struct perf_event *leader = event->group_leader, *child;
4409 struct perf_event_context *ctx = leader->ctx;
4413 lockdep_assert_held(&ctx->mutex);
4415 values = kzalloc(event->read_size, GFP_KERNEL);
4419 values[0] = 1 + leader->nr_siblings;
4422 * By locking the child_mutex of the leader we effectively
4423 * lock the child list of all siblings.. XXX explain how.
4425 mutex_lock(&leader->child_mutex);
4427 ret = __perf_read_group_add(leader, read_format, values);
4431 list_for_each_entry(child, &leader->child_list, child_list) {
4432 ret = __perf_read_group_add(child, read_format, values);
4437 mutex_unlock(&leader->child_mutex);
4439 ret = event->read_size;
4440 if (copy_to_user(buf, values, event->read_size))
4445 mutex_unlock(&leader->child_mutex);
4451 static int perf_read_one(struct perf_event *event,
4452 u64 read_format, char __user *buf)
4454 u64 enabled, running;
4458 values[n++] = perf_event_read_value(event, &enabled, &running);
4459 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4460 values[n++] = enabled;
4461 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4462 values[n++] = running;
4463 if (read_format & PERF_FORMAT_ID)
4464 values[n++] = primary_event_id(event);
4466 if (copy_to_user(buf, values, n * sizeof(u64)))
4469 return n * sizeof(u64);
4472 static bool is_event_hup(struct perf_event *event)
4476 if (event->state > PERF_EVENT_STATE_EXIT)
4479 mutex_lock(&event->child_mutex);
4480 no_children = list_empty(&event->child_list);
4481 mutex_unlock(&event->child_mutex);
4486 * Read the performance event - simple non blocking version for now
4489 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4491 u64 read_format = event->attr.read_format;
4495 * Return end-of-file for a read on a event that is in
4496 * error state (i.e. because it was pinned but it couldn't be
4497 * scheduled on to the CPU at some point).
4499 if (event->state == PERF_EVENT_STATE_ERROR)
4502 if (count < event->read_size)
4505 WARN_ON_ONCE(event->ctx->parent_ctx);
4506 if (read_format & PERF_FORMAT_GROUP)
4507 ret = perf_read_group(event, read_format, buf);
4509 ret = perf_read_one(event, read_format, buf);
4515 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4517 struct perf_event *event = file->private_data;
4518 struct perf_event_context *ctx;
4521 ctx = perf_event_ctx_lock(event);
4522 ret = __perf_read(event, buf, count);
4523 perf_event_ctx_unlock(event, ctx);
4528 static unsigned int perf_poll(struct file *file, poll_table *wait)
4530 struct perf_event *event = file->private_data;
4531 struct ring_buffer *rb;
4532 unsigned int events = POLLHUP;
4534 poll_wait(file, &event->waitq, wait);
4536 if (is_event_hup(event))
4540 * Pin the event->rb by taking event->mmap_mutex; otherwise
4541 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4543 mutex_lock(&event->mmap_mutex);
4546 events = atomic_xchg(&rb->poll, 0);
4547 mutex_unlock(&event->mmap_mutex);
4551 static void _perf_event_reset(struct perf_event *event)
4553 (void)perf_event_read(event, false);
4554 local64_set(&event->count, 0);
4555 perf_event_update_userpage(event);
4559 * Holding the top-level event's child_mutex means that any
4560 * descendant process that has inherited this event will block
4561 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4562 * task existence requirements of perf_event_enable/disable.
4564 static void perf_event_for_each_child(struct perf_event *event,
4565 void (*func)(struct perf_event *))
4567 struct perf_event *child;
4569 WARN_ON_ONCE(event->ctx->parent_ctx);
4571 mutex_lock(&event->child_mutex);
4573 list_for_each_entry(child, &event->child_list, child_list)
4575 mutex_unlock(&event->child_mutex);
4578 static void perf_event_for_each(struct perf_event *event,
4579 void (*func)(struct perf_event *))
4581 struct perf_event_context *ctx = event->ctx;
4582 struct perf_event *sibling;
4584 lockdep_assert_held(&ctx->mutex);
4586 event = event->group_leader;
4588 perf_event_for_each_child(event, func);
4589 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4590 perf_event_for_each_child(sibling, func);
4593 static void __perf_event_period(struct perf_event *event,
4594 struct perf_cpu_context *cpuctx,
4595 struct perf_event_context *ctx,
4598 u64 value = *((u64 *)info);
4601 if (event->attr.freq) {
4602 event->attr.sample_freq = value;
4604 event->attr.sample_period = value;
4605 event->hw.sample_period = value;
4608 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4610 perf_pmu_disable(ctx->pmu);
4612 * We could be throttled; unthrottle now to avoid the tick
4613 * trying to unthrottle while we already re-started the event.
4615 if (event->hw.interrupts == MAX_INTERRUPTS) {
4616 event->hw.interrupts = 0;
4617 perf_log_throttle(event, 1);
4619 event->pmu->stop(event, PERF_EF_UPDATE);
4622 local64_set(&event->hw.period_left, 0);
4625 event->pmu->start(event, PERF_EF_RELOAD);
4626 perf_pmu_enable(ctx->pmu);
4630 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4634 if (!is_sampling_event(event))
4637 if (copy_from_user(&value, arg, sizeof(value)))
4643 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4646 event_function_call(event, __perf_event_period, &value);
4651 static const struct file_operations perf_fops;
4653 static inline int perf_fget_light(int fd, struct fd *p)
4655 struct fd f = fdget(fd);
4659 if (f.file->f_op != &perf_fops) {
4667 static int perf_event_set_output(struct perf_event *event,
4668 struct perf_event *output_event);
4669 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4670 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4672 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4674 void (*func)(struct perf_event *);
4678 case PERF_EVENT_IOC_ENABLE:
4679 func = _perf_event_enable;
4681 case PERF_EVENT_IOC_DISABLE:
4682 func = _perf_event_disable;
4684 case PERF_EVENT_IOC_RESET:
4685 func = _perf_event_reset;
4688 case PERF_EVENT_IOC_REFRESH:
4689 return _perf_event_refresh(event, arg);
4691 case PERF_EVENT_IOC_PERIOD:
4692 return perf_event_period(event, (u64 __user *)arg);
4694 case PERF_EVENT_IOC_ID:
4696 u64 id = primary_event_id(event);
4698 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4703 case PERF_EVENT_IOC_SET_OUTPUT:
4707 struct perf_event *output_event;
4709 ret = perf_fget_light(arg, &output);
4712 output_event = output.file->private_data;
4713 ret = perf_event_set_output(event, output_event);
4716 ret = perf_event_set_output(event, NULL);
4721 case PERF_EVENT_IOC_SET_FILTER:
4722 return perf_event_set_filter(event, (void __user *)arg);
4724 case PERF_EVENT_IOC_SET_BPF:
4725 return perf_event_set_bpf_prog(event, arg);
4727 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4728 struct ring_buffer *rb;
4731 rb = rcu_dereference(event->rb);
4732 if (!rb || !rb->nr_pages) {
4736 rb_toggle_paused(rb, !!arg);
4744 if (flags & PERF_IOC_FLAG_GROUP)
4745 perf_event_for_each(event, func);
4747 perf_event_for_each_child(event, func);
4752 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4754 struct perf_event *event = file->private_data;
4755 struct perf_event_context *ctx;
4758 ctx = perf_event_ctx_lock(event);
4759 ret = _perf_ioctl(event, cmd, arg);
4760 perf_event_ctx_unlock(event, ctx);
4765 #ifdef CONFIG_COMPAT
4766 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4769 switch (_IOC_NR(cmd)) {
4770 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4771 case _IOC_NR(PERF_EVENT_IOC_ID):
4772 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4773 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4774 cmd &= ~IOCSIZE_MASK;
4775 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4779 return perf_ioctl(file, cmd, arg);
4782 # define perf_compat_ioctl NULL
4785 int perf_event_task_enable(void)
4787 struct perf_event_context *ctx;
4788 struct perf_event *event;
4790 mutex_lock(¤t->perf_event_mutex);
4791 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4792 ctx = perf_event_ctx_lock(event);
4793 perf_event_for_each_child(event, _perf_event_enable);
4794 perf_event_ctx_unlock(event, ctx);
4796 mutex_unlock(¤t->perf_event_mutex);
4801 int perf_event_task_disable(void)
4803 struct perf_event_context *ctx;
4804 struct perf_event *event;
4806 mutex_lock(¤t->perf_event_mutex);
4807 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4808 ctx = perf_event_ctx_lock(event);
4809 perf_event_for_each_child(event, _perf_event_disable);
4810 perf_event_ctx_unlock(event, ctx);
4812 mutex_unlock(¤t->perf_event_mutex);
4817 static int perf_event_index(struct perf_event *event)
4819 if (event->hw.state & PERF_HES_STOPPED)
4822 if (event->state != PERF_EVENT_STATE_ACTIVE)
4825 return event->pmu->event_idx(event);
4828 static void calc_timer_values(struct perf_event *event,
4835 *now = perf_clock();
4836 ctx_time = event->shadow_ctx_time + *now;
4837 *enabled = ctx_time - event->tstamp_enabled;
4838 *running = ctx_time - event->tstamp_running;
4841 static void perf_event_init_userpage(struct perf_event *event)
4843 struct perf_event_mmap_page *userpg;
4844 struct ring_buffer *rb;
4847 rb = rcu_dereference(event->rb);
4851 userpg = rb->user_page;
4853 /* Allow new userspace to detect that bit 0 is deprecated */
4854 userpg->cap_bit0_is_deprecated = 1;
4855 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4856 userpg->data_offset = PAGE_SIZE;
4857 userpg->data_size = perf_data_size(rb);
4863 void __weak arch_perf_update_userpage(
4864 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4869 * Callers need to ensure there can be no nesting of this function, otherwise
4870 * the seqlock logic goes bad. We can not serialize this because the arch
4871 * code calls this from NMI context.
4873 void perf_event_update_userpage(struct perf_event *event)
4875 struct perf_event_mmap_page *userpg;
4876 struct ring_buffer *rb;
4877 u64 enabled, running, now;
4880 rb = rcu_dereference(event->rb);
4885 * compute total_time_enabled, total_time_running
4886 * based on snapshot values taken when the event
4887 * was last scheduled in.
4889 * we cannot simply called update_context_time()
4890 * because of locking issue as we can be called in
4893 calc_timer_values(event, &now, &enabled, &running);
4895 userpg = rb->user_page;
4897 * Disable preemption so as to not let the corresponding user-space
4898 * spin too long if we get preempted.
4903 userpg->index = perf_event_index(event);
4904 userpg->offset = perf_event_count(event);
4906 userpg->offset -= local64_read(&event->hw.prev_count);
4908 userpg->time_enabled = enabled +
4909 atomic64_read(&event->child_total_time_enabled);
4911 userpg->time_running = running +
4912 atomic64_read(&event->child_total_time_running);
4914 arch_perf_update_userpage(event, userpg, now);
4923 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4925 struct perf_event *event = vma->vm_file->private_data;
4926 struct ring_buffer *rb;
4927 int ret = VM_FAULT_SIGBUS;
4929 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4930 if (vmf->pgoff == 0)
4936 rb = rcu_dereference(event->rb);
4940 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4943 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4947 get_page(vmf->page);
4948 vmf->page->mapping = vma->vm_file->f_mapping;
4949 vmf->page->index = vmf->pgoff;
4958 static void ring_buffer_attach(struct perf_event *event,
4959 struct ring_buffer *rb)
4961 struct ring_buffer *old_rb = NULL;
4962 unsigned long flags;
4966 * Should be impossible, we set this when removing
4967 * event->rb_entry and wait/clear when adding event->rb_entry.
4969 WARN_ON_ONCE(event->rcu_pending);
4972 spin_lock_irqsave(&old_rb->event_lock, flags);
4973 list_del_rcu(&event->rb_entry);
4974 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4976 event->rcu_batches = get_state_synchronize_rcu();
4977 event->rcu_pending = 1;
4981 if (event->rcu_pending) {
4982 cond_synchronize_rcu(event->rcu_batches);
4983 event->rcu_pending = 0;
4986 spin_lock_irqsave(&rb->event_lock, flags);
4987 list_add_rcu(&event->rb_entry, &rb->event_list);
4988 spin_unlock_irqrestore(&rb->event_lock, flags);
4992 * Avoid racing with perf_mmap_close(AUX): stop the event
4993 * before swizzling the event::rb pointer; if it's getting
4994 * unmapped, its aux_mmap_count will be 0 and it won't
4995 * restart. See the comment in __perf_pmu_output_stop().
4997 * Data will inevitably be lost when set_output is done in
4998 * mid-air, but then again, whoever does it like this is
4999 * not in for the data anyway.
5002 perf_event_stop(event, 0);
5004 rcu_assign_pointer(event->rb, rb);
5007 ring_buffer_put(old_rb);
5009 * Since we detached before setting the new rb, so that we
5010 * could attach the new rb, we could have missed a wakeup.
5013 wake_up_all(&event->waitq);
5017 static void ring_buffer_wakeup(struct perf_event *event)
5019 struct ring_buffer *rb;
5022 rb = rcu_dereference(event->rb);
5024 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5025 wake_up_all(&event->waitq);
5030 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5032 struct ring_buffer *rb;
5035 rb = rcu_dereference(event->rb);
5037 if (!atomic_inc_not_zero(&rb->refcount))
5045 void ring_buffer_put(struct ring_buffer *rb)
5047 if (!atomic_dec_and_test(&rb->refcount))
5050 WARN_ON_ONCE(!list_empty(&rb->event_list));
5052 call_rcu(&rb->rcu_head, rb_free_rcu);
5055 static void perf_mmap_open(struct vm_area_struct *vma)
5057 struct perf_event *event = vma->vm_file->private_data;
5059 atomic_inc(&event->mmap_count);
5060 atomic_inc(&event->rb->mmap_count);
5063 atomic_inc(&event->rb->aux_mmap_count);
5065 if (event->pmu->event_mapped)
5066 event->pmu->event_mapped(event);
5069 static void perf_pmu_output_stop(struct perf_event *event);
5072 * A buffer can be mmap()ed multiple times; either directly through the same
5073 * event, or through other events by use of perf_event_set_output().
5075 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5076 * the buffer here, where we still have a VM context. This means we need
5077 * to detach all events redirecting to us.
5079 static void perf_mmap_close(struct vm_area_struct *vma)
5081 struct perf_event *event = vma->vm_file->private_data;
5083 struct ring_buffer *rb = ring_buffer_get(event);
5084 struct user_struct *mmap_user = rb->mmap_user;
5085 int mmap_locked = rb->mmap_locked;
5086 unsigned long size = perf_data_size(rb);
5088 if (event->pmu->event_unmapped)
5089 event->pmu->event_unmapped(event);
5092 * rb->aux_mmap_count will always drop before rb->mmap_count and
5093 * event->mmap_count, so it is ok to use event->mmap_mutex to
5094 * serialize with perf_mmap here.
5096 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5097 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5099 * Stop all AUX events that are writing to this buffer,
5100 * so that we can free its AUX pages and corresponding PMU
5101 * data. Note that after rb::aux_mmap_count dropped to zero,
5102 * they won't start any more (see perf_aux_output_begin()).
5104 perf_pmu_output_stop(event);
5106 /* now it's safe to free the pages */
5107 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5108 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5110 /* this has to be the last one */
5112 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5114 mutex_unlock(&event->mmap_mutex);
5117 atomic_dec(&rb->mmap_count);
5119 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5122 ring_buffer_attach(event, NULL);
5123 mutex_unlock(&event->mmap_mutex);
5125 /* If there's still other mmap()s of this buffer, we're done. */
5126 if (atomic_read(&rb->mmap_count))
5130 * No other mmap()s, detach from all other events that might redirect
5131 * into the now unreachable buffer. Somewhat complicated by the
5132 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5136 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5137 if (!atomic_long_inc_not_zero(&event->refcount)) {
5139 * This event is en-route to free_event() which will
5140 * detach it and remove it from the list.
5146 mutex_lock(&event->mmap_mutex);
5148 * Check we didn't race with perf_event_set_output() which can
5149 * swizzle the rb from under us while we were waiting to
5150 * acquire mmap_mutex.
5152 * If we find a different rb; ignore this event, a next
5153 * iteration will no longer find it on the list. We have to
5154 * still restart the iteration to make sure we're not now
5155 * iterating the wrong list.
5157 if (event->rb == rb)
5158 ring_buffer_attach(event, NULL);
5160 mutex_unlock(&event->mmap_mutex);
5164 * Restart the iteration; either we're on the wrong list or
5165 * destroyed its integrity by doing a deletion.
5172 * It could be there's still a few 0-ref events on the list; they'll
5173 * get cleaned up by free_event() -- they'll also still have their
5174 * ref on the rb and will free it whenever they are done with it.
5176 * Aside from that, this buffer is 'fully' detached and unmapped,
5177 * undo the VM accounting.
5180 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5181 vma->vm_mm->pinned_vm -= mmap_locked;
5182 free_uid(mmap_user);
5185 ring_buffer_put(rb); /* could be last */
5188 static const struct vm_operations_struct perf_mmap_vmops = {
5189 .open = perf_mmap_open,
5190 .close = perf_mmap_close, /* non mergable */
5191 .fault = perf_mmap_fault,
5192 .page_mkwrite = perf_mmap_fault,
5195 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5197 struct perf_event *event = file->private_data;
5198 unsigned long user_locked, user_lock_limit;
5199 struct user_struct *user = current_user();
5200 unsigned long locked, lock_limit;
5201 struct ring_buffer *rb = NULL;
5202 unsigned long vma_size;
5203 unsigned long nr_pages;
5204 long user_extra = 0, extra = 0;
5205 int ret = 0, flags = 0;
5208 * Don't allow mmap() of inherited per-task counters. This would
5209 * create a performance issue due to all children writing to the
5212 if (event->cpu == -1 && event->attr.inherit)
5215 if (!(vma->vm_flags & VM_SHARED))
5218 vma_size = vma->vm_end - vma->vm_start;
5220 if (vma->vm_pgoff == 0) {
5221 nr_pages = (vma_size / PAGE_SIZE) - 1;
5224 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5225 * mapped, all subsequent mappings should have the same size
5226 * and offset. Must be above the normal perf buffer.
5228 u64 aux_offset, aux_size;
5233 nr_pages = vma_size / PAGE_SIZE;
5235 mutex_lock(&event->mmap_mutex);
5242 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5243 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5245 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5248 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5251 /* already mapped with a different offset */
5252 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5255 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5258 /* already mapped with a different size */
5259 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5262 if (!is_power_of_2(nr_pages))
5265 if (!atomic_inc_not_zero(&rb->mmap_count))
5268 if (rb_has_aux(rb)) {
5269 atomic_inc(&rb->aux_mmap_count);
5274 atomic_set(&rb->aux_mmap_count, 1);
5275 user_extra = nr_pages;
5281 * If we have rb pages ensure they're a power-of-two number, so we
5282 * can do bitmasks instead of modulo.
5284 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5287 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5290 WARN_ON_ONCE(event->ctx->parent_ctx);
5292 mutex_lock(&event->mmap_mutex);
5294 if (event->rb->nr_pages != nr_pages) {
5299 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5301 * Raced against perf_mmap_close() through
5302 * perf_event_set_output(). Try again, hope for better
5305 mutex_unlock(&event->mmap_mutex);
5312 user_extra = nr_pages + 1;
5315 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5318 * Increase the limit linearly with more CPUs:
5320 user_lock_limit *= num_online_cpus();
5322 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5324 if (user_locked > user_lock_limit)
5325 extra = user_locked - user_lock_limit;
5327 lock_limit = rlimit(RLIMIT_MEMLOCK);
5328 lock_limit >>= PAGE_SHIFT;
5329 locked = vma->vm_mm->pinned_vm + extra;
5331 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5332 !capable(CAP_IPC_LOCK)) {
5337 WARN_ON(!rb && event->rb);
5339 if (vma->vm_flags & VM_WRITE)
5340 flags |= RING_BUFFER_WRITABLE;
5343 rb = rb_alloc(nr_pages,
5344 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5352 atomic_set(&rb->mmap_count, 1);
5353 rb->mmap_user = get_current_user();
5354 rb->mmap_locked = extra;
5356 ring_buffer_attach(event, rb);
5358 perf_event_init_userpage(event);
5359 perf_event_update_userpage(event);
5361 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5362 event->attr.aux_watermark, flags);
5364 rb->aux_mmap_locked = extra;
5369 atomic_long_add(user_extra, &user->locked_vm);
5370 vma->vm_mm->pinned_vm += extra;
5372 atomic_inc(&event->mmap_count);
5374 atomic_dec(&rb->mmap_count);
5377 mutex_unlock(&event->mmap_mutex);
5380 * Since pinned accounting is per vm we cannot allow fork() to copy our
5383 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5384 vma->vm_ops = &perf_mmap_vmops;
5386 if (event->pmu->event_mapped)
5387 event->pmu->event_mapped(event);
5392 static int perf_fasync(int fd, struct file *filp, int on)
5394 struct inode *inode = file_inode(filp);
5395 struct perf_event *event = filp->private_data;
5399 retval = fasync_helper(fd, filp, on, &event->fasync);
5400 inode_unlock(inode);
5408 static const struct file_operations perf_fops = {
5409 .llseek = no_llseek,
5410 .release = perf_release,
5413 .unlocked_ioctl = perf_ioctl,
5414 .compat_ioctl = perf_compat_ioctl,
5416 .fasync = perf_fasync,
5422 * If there's data, ensure we set the poll() state and publish everything
5423 * to user-space before waking everybody up.
5426 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5428 /* only the parent has fasync state */
5430 event = event->parent;
5431 return &event->fasync;
5434 void perf_event_wakeup(struct perf_event *event)
5436 ring_buffer_wakeup(event);
5438 if (event->pending_kill) {
5439 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5440 event->pending_kill = 0;
5444 static void perf_pending_event(struct irq_work *entry)
5446 struct perf_event *event = container_of(entry,
5447 struct perf_event, pending);
5450 rctx = perf_swevent_get_recursion_context();
5452 * If we 'fail' here, that's OK, it means recursion is already disabled
5453 * and we won't recurse 'further'.
5456 if (event->pending_disable) {
5457 event->pending_disable = 0;
5458 perf_event_disable_local(event);
5461 if (event->pending_wakeup) {
5462 event->pending_wakeup = 0;
5463 perf_event_wakeup(event);
5467 perf_swevent_put_recursion_context(rctx);
5471 * We assume there is only KVM supporting the callbacks.
5472 * Later on, we might change it to a list if there is
5473 * another virtualization implementation supporting the callbacks.
5475 struct perf_guest_info_callbacks *perf_guest_cbs;
5477 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5479 perf_guest_cbs = cbs;
5482 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5484 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5486 perf_guest_cbs = NULL;
5489 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5492 perf_output_sample_regs(struct perf_output_handle *handle,
5493 struct pt_regs *regs, u64 mask)
5496 DECLARE_BITMAP(_mask, 64);
5498 bitmap_from_u64(_mask, mask);
5499 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5502 val = perf_reg_value(regs, bit);
5503 perf_output_put(handle, val);
5507 static void perf_sample_regs_user(struct perf_regs *regs_user,
5508 struct pt_regs *regs,
5509 struct pt_regs *regs_user_copy)
5511 if (user_mode(regs)) {
5512 regs_user->abi = perf_reg_abi(current);
5513 regs_user->regs = regs;
5514 } else if (current->mm) {
5515 perf_get_regs_user(regs_user, regs, regs_user_copy);
5517 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5518 regs_user->regs = NULL;
5522 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5523 struct pt_regs *regs)
5525 regs_intr->regs = regs;
5526 regs_intr->abi = perf_reg_abi(current);
5531 * Get remaining task size from user stack pointer.
5533 * It'd be better to take stack vma map and limit this more
5534 * precisly, but there's no way to get it safely under interrupt,
5535 * so using TASK_SIZE as limit.
5537 static u64 perf_ustack_task_size(struct pt_regs *regs)
5539 unsigned long addr = perf_user_stack_pointer(regs);
5541 if (!addr || addr >= TASK_SIZE)
5544 return TASK_SIZE - addr;
5548 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5549 struct pt_regs *regs)
5553 /* No regs, no stack pointer, no dump. */
5558 * Check if we fit in with the requested stack size into the:
5560 * If we don't, we limit the size to the TASK_SIZE.
5562 * - remaining sample size
5563 * If we don't, we customize the stack size to
5564 * fit in to the remaining sample size.
5567 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5568 stack_size = min(stack_size, (u16) task_size);
5570 /* Current header size plus static size and dynamic size. */
5571 header_size += 2 * sizeof(u64);
5573 /* Do we fit in with the current stack dump size? */
5574 if ((u16) (header_size + stack_size) < header_size) {
5576 * If we overflow the maximum size for the sample,
5577 * we customize the stack dump size to fit in.
5579 stack_size = USHRT_MAX - header_size - sizeof(u64);
5580 stack_size = round_up(stack_size, sizeof(u64));
5587 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5588 struct pt_regs *regs)
5590 /* Case of a kernel thread, nothing to dump */
5593 perf_output_put(handle, size);
5602 * - the size requested by user or the best one we can fit
5603 * in to the sample max size
5605 * - user stack dump data
5607 * - the actual dumped size
5611 perf_output_put(handle, dump_size);
5614 sp = perf_user_stack_pointer(regs);
5615 rem = __output_copy_user(handle, (void *) sp, dump_size);
5616 dyn_size = dump_size - rem;
5618 perf_output_skip(handle, rem);
5621 perf_output_put(handle, dyn_size);
5625 static void __perf_event_header__init_id(struct perf_event_header *header,
5626 struct perf_sample_data *data,
5627 struct perf_event *event)
5629 u64 sample_type = event->attr.sample_type;
5631 data->type = sample_type;
5632 header->size += event->id_header_size;
5634 if (sample_type & PERF_SAMPLE_TID) {
5635 /* namespace issues */
5636 data->tid_entry.pid = perf_event_pid(event, current);
5637 data->tid_entry.tid = perf_event_tid(event, current);
5640 if (sample_type & PERF_SAMPLE_TIME)
5641 data->time = perf_event_clock(event);
5643 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5644 data->id = primary_event_id(event);
5646 if (sample_type & PERF_SAMPLE_STREAM_ID)
5647 data->stream_id = event->id;
5649 if (sample_type & PERF_SAMPLE_CPU) {
5650 data->cpu_entry.cpu = raw_smp_processor_id();
5651 data->cpu_entry.reserved = 0;
5655 void perf_event_header__init_id(struct perf_event_header *header,
5656 struct perf_sample_data *data,
5657 struct perf_event *event)
5659 if (event->attr.sample_id_all)
5660 __perf_event_header__init_id(header, data, event);
5663 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5664 struct perf_sample_data *data)
5666 u64 sample_type = data->type;
5668 if (sample_type & PERF_SAMPLE_TID)
5669 perf_output_put(handle, data->tid_entry);
5671 if (sample_type & PERF_SAMPLE_TIME)
5672 perf_output_put(handle, data->time);
5674 if (sample_type & PERF_SAMPLE_ID)
5675 perf_output_put(handle, data->id);
5677 if (sample_type & PERF_SAMPLE_STREAM_ID)
5678 perf_output_put(handle, data->stream_id);
5680 if (sample_type & PERF_SAMPLE_CPU)
5681 perf_output_put(handle, data->cpu_entry);
5683 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5684 perf_output_put(handle, data->id);
5687 void perf_event__output_id_sample(struct perf_event *event,
5688 struct perf_output_handle *handle,
5689 struct perf_sample_data *sample)
5691 if (event->attr.sample_id_all)
5692 __perf_event__output_id_sample(handle, sample);
5695 static void perf_output_read_one(struct perf_output_handle *handle,
5696 struct perf_event *event,
5697 u64 enabled, u64 running)
5699 u64 read_format = event->attr.read_format;
5703 values[n++] = perf_event_count(event);
5704 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5705 values[n++] = enabled +
5706 atomic64_read(&event->child_total_time_enabled);
5708 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5709 values[n++] = running +
5710 atomic64_read(&event->child_total_time_running);
5712 if (read_format & PERF_FORMAT_ID)
5713 values[n++] = primary_event_id(event);
5715 __output_copy(handle, values, n * sizeof(u64));
5719 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5721 static void perf_output_read_group(struct perf_output_handle *handle,
5722 struct perf_event *event,
5723 u64 enabled, u64 running)
5725 struct perf_event *leader = event->group_leader, *sub;
5726 u64 read_format = event->attr.read_format;
5730 values[n++] = 1 + leader->nr_siblings;
5732 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5733 values[n++] = enabled;
5735 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5736 values[n++] = running;
5738 if (leader != event)
5739 leader->pmu->read(leader);
5741 values[n++] = perf_event_count(leader);
5742 if (read_format & PERF_FORMAT_ID)
5743 values[n++] = primary_event_id(leader);
5745 __output_copy(handle, values, n * sizeof(u64));
5747 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5750 if ((sub != event) &&
5751 (sub->state == PERF_EVENT_STATE_ACTIVE))
5752 sub->pmu->read(sub);
5754 values[n++] = perf_event_count(sub);
5755 if (read_format & PERF_FORMAT_ID)
5756 values[n++] = primary_event_id(sub);
5758 __output_copy(handle, values, n * sizeof(u64));
5762 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5763 PERF_FORMAT_TOTAL_TIME_RUNNING)
5765 static void perf_output_read(struct perf_output_handle *handle,
5766 struct perf_event *event)
5768 u64 enabled = 0, running = 0, now;
5769 u64 read_format = event->attr.read_format;
5772 * compute total_time_enabled, total_time_running
5773 * based on snapshot values taken when the event
5774 * was last scheduled in.
5776 * we cannot simply called update_context_time()
5777 * because of locking issue as we are called in
5780 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5781 calc_timer_values(event, &now, &enabled, &running);
5783 if (event->attr.read_format & PERF_FORMAT_GROUP)
5784 perf_output_read_group(handle, event, enabled, running);
5786 perf_output_read_one(handle, event, enabled, running);
5789 void perf_output_sample(struct perf_output_handle *handle,
5790 struct perf_event_header *header,
5791 struct perf_sample_data *data,
5792 struct perf_event *event)
5794 u64 sample_type = data->type;
5796 perf_output_put(handle, *header);
5798 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5799 perf_output_put(handle, data->id);
5801 if (sample_type & PERF_SAMPLE_IP)
5802 perf_output_put(handle, data->ip);
5804 if (sample_type & PERF_SAMPLE_TID)
5805 perf_output_put(handle, data->tid_entry);
5807 if (sample_type & PERF_SAMPLE_TIME)
5808 perf_output_put(handle, data->time);
5810 if (sample_type & PERF_SAMPLE_ADDR)
5811 perf_output_put(handle, data->addr);
5813 if (sample_type & PERF_SAMPLE_ID)
5814 perf_output_put(handle, data->id);
5816 if (sample_type & PERF_SAMPLE_STREAM_ID)
5817 perf_output_put(handle, data->stream_id);
5819 if (sample_type & PERF_SAMPLE_CPU)
5820 perf_output_put(handle, data->cpu_entry);
5822 if (sample_type & PERF_SAMPLE_PERIOD)
5823 perf_output_put(handle, data->period);
5825 if (sample_type & PERF_SAMPLE_READ)
5826 perf_output_read(handle, event);
5828 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5829 if (data->callchain) {
5832 if (data->callchain)
5833 size += data->callchain->nr;
5835 size *= sizeof(u64);
5837 __output_copy(handle, data->callchain, size);
5840 perf_output_put(handle, nr);
5844 if (sample_type & PERF_SAMPLE_RAW) {
5845 struct perf_raw_record *raw = data->raw;
5848 struct perf_raw_frag *frag = &raw->frag;
5850 perf_output_put(handle, raw->size);
5853 __output_custom(handle, frag->copy,
5854 frag->data, frag->size);
5856 __output_copy(handle, frag->data,
5859 if (perf_raw_frag_last(frag))
5864 __output_skip(handle, NULL, frag->pad);
5870 .size = sizeof(u32),
5873 perf_output_put(handle, raw);
5877 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5878 if (data->br_stack) {
5881 size = data->br_stack->nr
5882 * sizeof(struct perf_branch_entry);
5884 perf_output_put(handle, data->br_stack->nr);
5885 perf_output_copy(handle, data->br_stack->entries, size);
5888 * we always store at least the value of nr
5891 perf_output_put(handle, nr);
5895 if (sample_type & PERF_SAMPLE_REGS_USER) {
5896 u64 abi = data->regs_user.abi;
5899 * If there are no regs to dump, notice it through
5900 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5902 perf_output_put(handle, abi);
5905 u64 mask = event->attr.sample_regs_user;
5906 perf_output_sample_regs(handle,
5907 data->regs_user.regs,
5912 if (sample_type & PERF_SAMPLE_STACK_USER) {
5913 perf_output_sample_ustack(handle,
5914 data->stack_user_size,
5915 data->regs_user.regs);
5918 if (sample_type & PERF_SAMPLE_WEIGHT)
5919 perf_output_put(handle, data->weight);
5921 if (sample_type & PERF_SAMPLE_DATA_SRC)
5922 perf_output_put(handle, data->data_src.val);
5924 if (sample_type & PERF_SAMPLE_TRANSACTION)
5925 perf_output_put(handle, data->txn);
5927 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5928 u64 abi = data->regs_intr.abi;
5930 * If there are no regs to dump, notice it through
5931 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5933 perf_output_put(handle, abi);
5936 u64 mask = event->attr.sample_regs_intr;
5938 perf_output_sample_regs(handle,
5939 data->regs_intr.regs,
5944 if (!event->attr.watermark) {
5945 int wakeup_events = event->attr.wakeup_events;
5947 if (wakeup_events) {
5948 struct ring_buffer *rb = handle->rb;
5949 int events = local_inc_return(&rb->events);
5951 if (events >= wakeup_events) {
5952 local_sub(wakeup_events, &rb->events);
5953 local_inc(&rb->wakeup);
5959 void perf_prepare_sample(struct perf_event_header *header,
5960 struct perf_sample_data *data,
5961 struct perf_event *event,
5962 struct pt_regs *regs)
5964 u64 sample_type = event->attr.sample_type;
5966 header->type = PERF_RECORD_SAMPLE;
5967 header->size = sizeof(*header) + event->header_size;
5970 header->misc |= perf_misc_flags(regs);
5972 __perf_event_header__init_id(header, data, event);
5974 if (sample_type & PERF_SAMPLE_IP)
5975 data->ip = perf_instruction_pointer(regs);
5977 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5980 data->callchain = perf_callchain(event, regs);
5982 if (data->callchain)
5983 size += data->callchain->nr;
5985 header->size += size * sizeof(u64);
5988 if (sample_type & PERF_SAMPLE_RAW) {
5989 struct perf_raw_record *raw = data->raw;
5993 struct perf_raw_frag *frag = &raw->frag;
5998 if (perf_raw_frag_last(frag))
6003 size = round_up(sum + sizeof(u32), sizeof(u64));
6004 raw->size = size - sizeof(u32);
6005 frag->pad = raw->size - sum;
6010 header->size += size;
6013 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6014 int size = sizeof(u64); /* nr */
6015 if (data->br_stack) {
6016 size += data->br_stack->nr
6017 * sizeof(struct perf_branch_entry);
6019 header->size += size;
6022 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6023 perf_sample_regs_user(&data->regs_user, regs,
6024 &data->regs_user_copy);
6026 if (sample_type & PERF_SAMPLE_REGS_USER) {
6027 /* regs dump ABI info */
6028 int size = sizeof(u64);
6030 if (data->regs_user.regs) {
6031 u64 mask = event->attr.sample_regs_user;
6032 size += hweight64(mask) * sizeof(u64);
6035 header->size += size;
6038 if (sample_type & PERF_SAMPLE_STACK_USER) {
6040 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6041 * processed as the last one or have additional check added
6042 * in case new sample type is added, because we could eat
6043 * up the rest of the sample size.
6045 u16 stack_size = event->attr.sample_stack_user;
6046 u16 size = sizeof(u64);
6048 stack_size = perf_sample_ustack_size(stack_size, header->size,
6049 data->regs_user.regs);
6052 * If there is something to dump, add space for the dump
6053 * itself and for the field that tells the dynamic size,
6054 * which is how many have been actually dumped.
6057 size += sizeof(u64) + stack_size;
6059 data->stack_user_size = stack_size;
6060 header->size += size;
6063 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6064 /* regs dump ABI info */
6065 int size = sizeof(u64);
6067 perf_sample_regs_intr(&data->regs_intr, regs);
6069 if (data->regs_intr.regs) {
6070 u64 mask = event->attr.sample_regs_intr;
6072 size += hweight64(mask) * sizeof(u64);
6075 header->size += size;
6079 static void __always_inline
6080 __perf_event_output(struct perf_event *event,
6081 struct perf_sample_data *data,
6082 struct pt_regs *regs,
6083 int (*output_begin)(struct perf_output_handle *,
6084 struct perf_event *,
6087 struct perf_output_handle handle;
6088 struct perf_event_header header;
6090 /* protect the callchain buffers */
6093 perf_prepare_sample(&header, data, event, regs);
6095 if (output_begin(&handle, event, header.size))
6098 perf_output_sample(&handle, &header, data, event);
6100 perf_output_end(&handle);
6107 perf_event_output_forward(struct perf_event *event,
6108 struct perf_sample_data *data,
6109 struct pt_regs *regs)
6111 __perf_event_output(event, data, regs, perf_output_begin_forward);
6115 perf_event_output_backward(struct perf_event *event,
6116 struct perf_sample_data *data,
6117 struct pt_regs *regs)
6119 __perf_event_output(event, data, regs, perf_output_begin_backward);
6123 perf_event_output(struct perf_event *event,
6124 struct perf_sample_data *data,
6125 struct pt_regs *regs)
6127 __perf_event_output(event, data, regs, perf_output_begin);
6134 struct perf_read_event {
6135 struct perf_event_header header;
6142 perf_event_read_event(struct perf_event *event,
6143 struct task_struct *task)
6145 struct perf_output_handle handle;
6146 struct perf_sample_data sample;
6147 struct perf_read_event read_event = {
6149 .type = PERF_RECORD_READ,
6151 .size = sizeof(read_event) + event->read_size,
6153 .pid = perf_event_pid(event, task),
6154 .tid = perf_event_tid(event, task),
6158 perf_event_header__init_id(&read_event.header, &sample, event);
6159 ret = perf_output_begin(&handle, event, read_event.header.size);
6163 perf_output_put(&handle, read_event);
6164 perf_output_read(&handle, event);
6165 perf_event__output_id_sample(event, &handle, &sample);
6167 perf_output_end(&handle);
6170 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6173 perf_iterate_ctx(struct perf_event_context *ctx,
6174 perf_iterate_f output,
6175 void *data, bool all)
6177 struct perf_event *event;
6179 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6181 if (event->state < PERF_EVENT_STATE_INACTIVE)
6183 if (!event_filter_match(event))
6187 output(event, data);
6191 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6193 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6194 struct perf_event *event;
6196 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6198 * Skip events that are not fully formed yet; ensure that
6199 * if we observe event->ctx, both event and ctx will be
6200 * complete enough. See perf_install_in_context().
6202 if (!smp_load_acquire(&event->ctx))
6205 if (event->state < PERF_EVENT_STATE_INACTIVE)
6207 if (!event_filter_match(event))
6209 output(event, data);
6214 * Iterate all events that need to receive side-band events.
6216 * For new callers; ensure that account_pmu_sb_event() includes
6217 * your event, otherwise it might not get delivered.
6220 perf_iterate_sb(perf_iterate_f output, void *data,
6221 struct perf_event_context *task_ctx)
6223 struct perf_event_context *ctx;
6230 * If we have task_ctx != NULL we only notify the task context itself.
6231 * The task_ctx is set only for EXIT events before releasing task
6235 perf_iterate_ctx(task_ctx, output, data, false);
6239 perf_iterate_sb_cpu(output, data);
6241 for_each_task_context_nr(ctxn) {
6242 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6244 perf_iterate_ctx(ctx, output, data, false);
6252 * Clear all file-based filters at exec, they'll have to be
6253 * re-instated when/if these objects are mmapped again.
6255 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6257 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6258 struct perf_addr_filter *filter;
6259 unsigned int restart = 0, count = 0;
6260 unsigned long flags;
6262 if (!has_addr_filter(event))
6265 raw_spin_lock_irqsave(&ifh->lock, flags);
6266 list_for_each_entry(filter, &ifh->list, entry) {
6267 if (filter->inode) {
6268 event->addr_filters_offs[count] = 0;
6276 event->addr_filters_gen++;
6277 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6280 perf_event_stop(event, 1);
6283 void perf_event_exec(void)
6285 struct perf_event_context *ctx;
6289 for_each_task_context_nr(ctxn) {
6290 ctx = current->perf_event_ctxp[ctxn];
6294 perf_event_enable_on_exec(ctxn);
6296 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6302 struct remote_output {
6303 struct ring_buffer *rb;
6307 static void __perf_event_output_stop(struct perf_event *event, void *data)
6309 struct perf_event *parent = event->parent;
6310 struct remote_output *ro = data;
6311 struct ring_buffer *rb = ro->rb;
6312 struct stop_event_data sd = {
6316 if (!has_aux(event))
6323 * In case of inheritance, it will be the parent that links to the
6324 * ring-buffer, but it will be the child that's actually using it.
6326 * We are using event::rb to determine if the event should be stopped,
6327 * however this may race with ring_buffer_attach() (through set_output),
6328 * which will make us skip the event that actually needs to be stopped.
6329 * So ring_buffer_attach() has to stop an aux event before re-assigning
6332 if (rcu_dereference(parent->rb) == rb)
6333 ro->err = __perf_event_stop(&sd);
6336 static int __perf_pmu_output_stop(void *info)
6338 struct perf_event *event = info;
6339 struct pmu *pmu = event->pmu;
6340 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6341 struct remote_output ro = {
6346 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6347 if (cpuctx->task_ctx)
6348 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6355 static void perf_pmu_output_stop(struct perf_event *event)
6357 struct perf_event *iter;
6362 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6364 * For per-CPU events, we need to make sure that neither they
6365 * nor their children are running; for cpu==-1 events it's
6366 * sufficient to stop the event itself if it's active, since
6367 * it can't have children.
6371 cpu = READ_ONCE(iter->oncpu);
6376 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6377 if (err == -EAGAIN) {
6386 * task tracking -- fork/exit
6388 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6391 struct perf_task_event {
6392 struct task_struct *task;
6393 struct perf_event_context *task_ctx;
6396 struct perf_event_header header;
6406 static int perf_event_task_match(struct perf_event *event)
6408 return event->attr.comm || event->attr.mmap ||
6409 event->attr.mmap2 || event->attr.mmap_data ||
6413 static void perf_event_task_output(struct perf_event *event,
6416 struct perf_task_event *task_event = data;
6417 struct perf_output_handle handle;
6418 struct perf_sample_data sample;
6419 struct task_struct *task = task_event->task;
6420 int ret, size = task_event->event_id.header.size;
6422 if (!perf_event_task_match(event))
6425 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6427 ret = perf_output_begin(&handle, event,
6428 task_event->event_id.header.size);
6432 task_event->event_id.pid = perf_event_pid(event, task);
6433 task_event->event_id.ppid = perf_event_pid(event, current);
6435 task_event->event_id.tid = perf_event_tid(event, task);
6436 task_event->event_id.ptid = perf_event_tid(event, current);
6438 task_event->event_id.time = perf_event_clock(event);
6440 perf_output_put(&handle, task_event->event_id);
6442 perf_event__output_id_sample(event, &handle, &sample);
6444 perf_output_end(&handle);
6446 task_event->event_id.header.size = size;
6449 static void perf_event_task(struct task_struct *task,
6450 struct perf_event_context *task_ctx,
6453 struct perf_task_event task_event;
6455 if (!atomic_read(&nr_comm_events) &&
6456 !atomic_read(&nr_mmap_events) &&
6457 !atomic_read(&nr_task_events))
6460 task_event = (struct perf_task_event){
6462 .task_ctx = task_ctx,
6465 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6467 .size = sizeof(task_event.event_id),
6477 perf_iterate_sb(perf_event_task_output,
6482 void perf_event_fork(struct task_struct *task)
6484 perf_event_task(task, NULL, 1);
6491 struct perf_comm_event {
6492 struct task_struct *task;
6497 struct perf_event_header header;
6504 static int perf_event_comm_match(struct perf_event *event)
6506 return event->attr.comm;
6509 static void perf_event_comm_output(struct perf_event *event,
6512 struct perf_comm_event *comm_event = data;
6513 struct perf_output_handle handle;
6514 struct perf_sample_data sample;
6515 int size = comm_event->event_id.header.size;
6518 if (!perf_event_comm_match(event))
6521 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6522 ret = perf_output_begin(&handle, event,
6523 comm_event->event_id.header.size);
6528 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6529 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6531 perf_output_put(&handle, comm_event->event_id);
6532 __output_copy(&handle, comm_event->comm,
6533 comm_event->comm_size);
6535 perf_event__output_id_sample(event, &handle, &sample);
6537 perf_output_end(&handle);
6539 comm_event->event_id.header.size = size;
6542 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6544 char comm[TASK_COMM_LEN];
6547 memset(comm, 0, sizeof(comm));
6548 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6549 size = ALIGN(strlen(comm)+1, sizeof(u64));
6551 comm_event->comm = comm;
6552 comm_event->comm_size = size;
6554 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6556 perf_iterate_sb(perf_event_comm_output,
6561 void perf_event_comm(struct task_struct *task, bool exec)
6563 struct perf_comm_event comm_event;
6565 if (!atomic_read(&nr_comm_events))
6568 comm_event = (struct perf_comm_event){
6574 .type = PERF_RECORD_COMM,
6575 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6583 perf_event_comm_event(&comm_event);
6590 struct perf_mmap_event {
6591 struct vm_area_struct *vma;
6593 const char *file_name;
6601 struct perf_event_header header;
6611 static int perf_event_mmap_match(struct perf_event *event,
6614 struct perf_mmap_event *mmap_event = data;
6615 struct vm_area_struct *vma = mmap_event->vma;
6616 int executable = vma->vm_flags & VM_EXEC;
6618 return (!executable && event->attr.mmap_data) ||
6619 (executable && (event->attr.mmap || event->attr.mmap2));
6622 static void perf_event_mmap_output(struct perf_event *event,
6625 struct perf_mmap_event *mmap_event = data;
6626 struct perf_output_handle handle;
6627 struct perf_sample_data sample;
6628 int size = mmap_event->event_id.header.size;
6631 if (!perf_event_mmap_match(event, data))
6634 if (event->attr.mmap2) {
6635 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6636 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6637 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6638 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6639 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6640 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6641 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6644 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6645 ret = perf_output_begin(&handle, event,
6646 mmap_event->event_id.header.size);
6650 mmap_event->event_id.pid = perf_event_pid(event, current);
6651 mmap_event->event_id.tid = perf_event_tid(event, current);
6653 perf_output_put(&handle, mmap_event->event_id);
6655 if (event->attr.mmap2) {
6656 perf_output_put(&handle, mmap_event->maj);
6657 perf_output_put(&handle, mmap_event->min);
6658 perf_output_put(&handle, mmap_event->ino);
6659 perf_output_put(&handle, mmap_event->ino_generation);
6660 perf_output_put(&handle, mmap_event->prot);
6661 perf_output_put(&handle, mmap_event->flags);
6664 __output_copy(&handle, mmap_event->file_name,
6665 mmap_event->file_size);
6667 perf_event__output_id_sample(event, &handle, &sample);
6669 perf_output_end(&handle);
6671 mmap_event->event_id.header.size = size;
6674 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6676 struct vm_area_struct *vma = mmap_event->vma;
6677 struct file *file = vma->vm_file;
6678 int maj = 0, min = 0;
6679 u64 ino = 0, gen = 0;
6680 u32 prot = 0, flags = 0;
6686 if (vma->vm_flags & VM_READ)
6688 if (vma->vm_flags & VM_WRITE)
6690 if (vma->vm_flags & VM_EXEC)
6693 if (vma->vm_flags & VM_MAYSHARE)
6696 flags = MAP_PRIVATE;
6698 if (vma->vm_flags & VM_DENYWRITE)
6699 flags |= MAP_DENYWRITE;
6700 if (vma->vm_flags & VM_MAYEXEC)
6701 flags |= MAP_EXECUTABLE;
6702 if (vma->vm_flags & VM_LOCKED)
6703 flags |= MAP_LOCKED;
6704 if (vma->vm_flags & VM_HUGETLB)
6705 flags |= MAP_HUGETLB;
6708 struct inode *inode;
6711 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6717 * d_path() works from the end of the rb backwards, so we
6718 * need to add enough zero bytes after the string to handle
6719 * the 64bit alignment we do later.
6721 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6726 inode = file_inode(vma->vm_file);
6727 dev = inode->i_sb->s_dev;
6729 gen = inode->i_generation;
6735 if (vma->vm_ops && vma->vm_ops->name) {
6736 name = (char *) vma->vm_ops->name(vma);
6741 name = (char *)arch_vma_name(vma);
6745 if (vma->vm_start <= vma->vm_mm->start_brk &&
6746 vma->vm_end >= vma->vm_mm->brk) {
6750 if (vma->vm_start <= vma->vm_mm->start_stack &&
6751 vma->vm_end >= vma->vm_mm->start_stack) {
6761 strlcpy(tmp, name, sizeof(tmp));
6765 * Since our buffer works in 8 byte units we need to align our string
6766 * size to a multiple of 8. However, we must guarantee the tail end is
6767 * zero'd out to avoid leaking random bits to userspace.
6769 size = strlen(name)+1;
6770 while (!IS_ALIGNED(size, sizeof(u64)))
6771 name[size++] = '\0';
6773 mmap_event->file_name = name;
6774 mmap_event->file_size = size;
6775 mmap_event->maj = maj;
6776 mmap_event->min = min;
6777 mmap_event->ino = ino;
6778 mmap_event->ino_generation = gen;
6779 mmap_event->prot = prot;
6780 mmap_event->flags = flags;
6782 if (!(vma->vm_flags & VM_EXEC))
6783 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6785 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6787 perf_iterate_sb(perf_event_mmap_output,
6795 * Check whether inode and address range match filter criteria.
6797 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6798 struct file *file, unsigned long offset,
6801 if (filter->inode != file_inode(file))
6804 if (filter->offset > offset + size)
6807 if (filter->offset + filter->size < offset)
6813 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6815 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6816 struct vm_area_struct *vma = data;
6817 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6818 struct file *file = vma->vm_file;
6819 struct perf_addr_filter *filter;
6820 unsigned int restart = 0, count = 0;
6822 if (!has_addr_filter(event))
6828 raw_spin_lock_irqsave(&ifh->lock, flags);
6829 list_for_each_entry(filter, &ifh->list, entry) {
6830 if (perf_addr_filter_match(filter, file, off,
6831 vma->vm_end - vma->vm_start)) {
6832 event->addr_filters_offs[count] = vma->vm_start;
6840 event->addr_filters_gen++;
6841 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6844 perf_event_stop(event, 1);
6848 * Adjust all task's events' filters to the new vma
6850 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6852 struct perf_event_context *ctx;
6856 * Data tracing isn't supported yet and as such there is no need
6857 * to keep track of anything that isn't related to executable code:
6859 if (!(vma->vm_flags & VM_EXEC))
6863 for_each_task_context_nr(ctxn) {
6864 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6868 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6873 void perf_event_mmap(struct vm_area_struct *vma)
6875 struct perf_mmap_event mmap_event;
6877 if (!atomic_read(&nr_mmap_events))
6880 mmap_event = (struct perf_mmap_event){
6886 .type = PERF_RECORD_MMAP,
6887 .misc = PERF_RECORD_MISC_USER,
6892 .start = vma->vm_start,
6893 .len = vma->vm_end - vma->vm_start,
6894 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6896 /* .maj (attr_mmap2 only) */
6897 /* .min (attr_mmap2 only) */
6898 /* .ino (attr_mmap2 only) */
6899 /* .ino_generation (attr_mmap2 only) */
6900 /* .prot (attr_mmap2 only) */
6901 /* .flags (attr_mmap2 only) */
6904 perf_addr_filters_adjust(vma);
6905 perf_event_mmap_event(&mmap_event);
6908 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6909 unsigned long size, u64 flags)
6911 struct perf_output_handle handle;
6912 struct perf_sample_data sample;
6913 struct perf_aux_event {
6914 struct perf_event_header header;
6920 .type = PERF_RECORD_AUX,
6922 .size = sizeof(rec),
6930 perf_event_header__init_id(&rec.header, &sample, event);
6931 ret = perf_output_begin(&handle, event, rec.header.size);
6936 perf_output_put(&handle, rec);
6937 perf_event__output_id_sample(event, &handle, &sample);
6939 perf_output_end(&handle);
6943 * Lost/dropped samples logging
6945 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6947 struct perf_output_handle handle;
6948 struct perf_sample_data sample;
6952 struct perf_event_header header;
6954 } lost_samples_event = {
6956 .type = PERF_RECORD_LOST_SAMPLES,
6958 .size = sizeof(lost_samples_event),
6963 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6965 ret = perf_output_begin(&handle, event,
6966 lost_samples_event.header.size);
6970 perf_output_put(&handle, lost_samples_event);
6971 perf_event__output_id_sample(event, &handle, &sample);
6972 perf_output_end(&handle);
6976 * context_switch tracking
6979 struct perf_switch_event {
6980 struct task_struct *task;
6981 struct task_struct *next_prev;
6984 struct perf_event_header header;
6990 static int perf_event_switch_match(struct perf_event *event)
6992 return event->attr.context_switch;
6995 static void perf_event_switch_output(struct perf_event *event, void *data)
6997 struct perf_switch_event *se = data;
6998 struct perf_output_handle handle;
6999 struct perf_sample_data sample;
7002 if (!perf_event_switch_match(event))
7005 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7006 if (event->ctx->task) {
7007 se->event_id.header.type = PERF_RECORD_SWITCH;
7008 se->event_id.header.size = sizeof(se->event_id.header);
7010 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7011 se->event_id.header.size = sizeof(se->event_id);
7012 se->event_id.next_prev_pid =
7013 perf_event_pid(event, se->next_prev);
7014 se->event_id.next_prev_tid =
7015 perf_event_tid(event, se->next_prev);
7018 perf_event_header__init_id(&se->event_id.header, &sample, event);
7020 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7024 if (event->ctx->task)
7025 perf_output_put(&handle, se->event_id.header);
7027 perf_output_put(&handle, se->event_id);
7029 perf_event__output_id_sample(event, &handle, &sample);
7031 perf_output_end(&handle);
7034 static void perf_event_switch(struct task_struct *task,
7035 struct task_struct *next_prev, bool sched_in)
7037 struct perf_switch_event switch_event;
7039 /* N.B. caller checks nr_switch_events != 0 */
7041 switch_event = (struct perf_switch_event){
7043 .next_prev = next_prev,
7047 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7050 /* .next_prev_pid */
7051 /* .next_prev_tid */
7055 perf_iterate_sb(perf_event_switch_output,
7061 * IRQ throttle logging
7064 static void perf_log_throttle(struct perf_event *event, int enable)
7066 struct perf_output_handle handle;
7067 struct perf_sample_data sample;
7071 struct perf_event_header header;
7075 } throttle_event = {
7077 .type = PERF_RECORD_THROTTLE,
7079 .size = sizeof(throttle_event),
7081 .time = perf_event_clock(event),
7082 .id = primary_event_id(event),
7083 .stream_id = event->id,
7087 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7089 perf_event_header__init_id(&throttle_event.header, &sample, event);
7091 ret = perf_output_begin(&handle, event,
7092 throttle_event.header.size);
7096 perf_output_put(&handle, throttle_event);
7097 perf_event__output_id_sample(event, &handle, &sample);
7098 perf_output_end(&handle);
7101 static void perf_log_itrace_start(struct perf_event *event)
7103 struct perf_output_handle handle;
7104 struct perf_sample_data sample;
7105 struct perf_aux_event {
7106 struct perf_event_header header;
7113 event = event->parent;
7115 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7116 event->hw.itrace_started)
7119 rec.header.type = PERF_RECORD_ITRACE_START;
7120 rec.header.misc = 0;
7121 rec.header.size = sizeof(rec);
7122 rec.pid = perf_event_pid(event, current);
7123 rec.tid = perf_event_tid(event, current);
7125 perf_event_header__init_id(&rec.header, &sample, event);
7126 ret = perf_output_begin(&handle, event, rec.header.size);
7131 perf_output_put(&handle, rec);
7132 perf_event__output_id_sample(event, &handle, &sample);
7134 perf_output_end(&handle);
7138 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7140 struct hw_perf_event *hwc = &event->hw;
7144 seq = __this_cpu_read(perf_throttled_seq);
7145 if (seq != hwc->interrupts_seq) {
7146 hwc->interrupts_seq = seq;
7147 hwc->interrupts = 1;
7150 if (unlikely(throttle
7151 && hwc->interrupts >= max_samples_per_tick)) {
7152 __this_cpu_inc(perf_throttled_count);
7153 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7154 hwc->interrupts = MAX_INTERRUPTS;
7155 perf_log_throttle(event, 0);
7160 if (event->attr.freq) {
7161 u64 now = perf_clock();
7162 s64 delta = now - hwc->freq_time_stamp;
7164 hwc->freq_time_stamp = now;
7166 if (delta > 0 && delta < 2*TICK_NSEC)
7167 perf_adjust_period(event, delta, hwc->last_period, true);
7173 int perf_event_account_interrupt(struct perf_event *event)
7175 return __perf_event_account_interrupt(event, 1);
7179 * Generic event overflow handling, sampling.
7182 static int __perf_event_overflow(struct perf_event *event,
7183 int throttle, struct perf_sample_data *data,
7184 struct pt_regs *regs)
7186 int events = atomic_read(&event->event_limit);
7190 * Non-sampling counters might still use the PMI to fold short
7191 * hardware counters, ignore those.
7193 if (unlikely(!is_sampling_event(event)))
7196 ret = __perf_event_account_interrupt(event, throttle);
7199 * XXX event_limit might not quite work as expected on inherited
7203 event->pending_kill = POLL_IN;
7204 if (events && atomic_dec_and_test(&event->event_limit)) {
7206 event->pending_kill = POLL_HUP;
7208 perf_event_disable_inatomic(event);
7211 READ_ONCE(event->overflow_handler)(event, data, regs);
7213 if (*perf_event_fasync(event) && event->pending_kill) {
7214 event->pending_wakeup = 1;
7215 irq_work_queue(&event->pending);
7221 int perf_event_overflow(struct perf_event *event,
7222 struct perf_sample_data *data,
7223 struct pt_regs *regs)
7225 return __perf_event_overflow(event, 1, data, regs);
7229 * Generic software event infrastructure
7232 struct swevent_htable {
7233 struct swevent_hlist *swevent_hlist;
7234 struct mutex hlist_mutex;
7237 /* Recursion avoidance in each contexts */
7238 int recursion[PERF_NR_CONTEXTS];
7241 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7244 * We directly increment event->count and keep a second value in
7245 * event->hw.period_left to count intervals. This period event
7246 * is kept in the range [-sample_period, 0] so that we can use the
7250 u64 perf_swevent_set_period(struct perf_event *event)
7252 struct hw_perf_event *hwc = &event->hw;
7253 u64 period = hwc->last_period;
7257 hwc->last_period = hwc->sample_period;
7260 old = val = local64_read(&hwc->period_left);
7264 nr = div64_u64(period + val, period);
7265 offset = nr * period;
7267 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7273 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7274 struct perf_sample_data *data,
7275 struct pt_regs *regs)
7277 struct hw_perf_event *hwc = &event->hw;
7281 overflow = perf_swevent_set_period(event);
7283 if (hwc->interrupts == MAX_INTERRUPTS)
7286 for (; overflow; overflow--) {
7287 if (__perf_event_overflow(event, throttle,
7290 * We inhibit the overflow from happening when
7291 * hwc->interrupts == MAX_INTERRUPTS.
7299 static void perf_swevent_event(struct perf_event *event, u64 nr,
7300 struct perf_sample_data *data,
7301 struct pt_regs *regs)
7303 struct hw_perf_event *hwc = &event->hw;
7305 local64_add(nr, &event->count);
7310 if (!is_sampling_event(event))
7313 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7315 return perf_swevent_overflow(event, 1, data, regs);
7317 data->period = event->hw.last_period;
7319 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7320 return perf_swevent_overflow(event, 1, data, regs);
7322 if (local64_add_negative(nr, &hwc->period_left))
7325 perf_swevent_overflow(event, 0, data, regs);
7328 static int perf_exclude_event(struct perf_event *event,
7329 struct pt_regs *regs)
7331 if (event->hw.state & PERF_HES_STOPPED)
7335 if (event->attr.exclude_user && user_mode(regs))
7338 if (event->attr.exclude_kernel && !user_mode(regs))
7345 static int perf_swevent_match(struct perf_event *event,
7346 enum perf_type_id type,
7348 struct perf_sample_data *data,
7349 struct pt_regs *regs)
7351 if (event->attr.type != type)
7354 if (event->attr.config != event_id)
7357 if (perf_exclude_event(event, regs))
7363 static inline u64 swevent_hash(u64 type, u32 event_id)
7365 u64 val = event_id | (type << 32);
7367 return hash_64(val, SWEVENT_HLIST_BITS);
7370 static inline struct hlist_head *
7371 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7373 u64 hash = swevent_hash(type, event_id);
7375 return &hlist->heads[hash];
7378 /* For the read side: events when they trigger */
7379 static inline struct hlist_head *
7380 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7382 struct swevent_hlist *hlist;
7384 hlist = rcu_dereference(swhash->swevent_hlist);
7388 return __find_swevent_head(hlist, type, event_id);
7391 /* For the event head insertion and removal in the hlist */
7392 static inline struct hlist_head *
7393 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7395 struct swevent_hlist *hlist;
7396 u32 event_id = event->attr.config;
7397 u64 type = event->attr.type;
7400 * Event scheduling is always serialized against hlist allocation
7401 * and release. Which makes the protected version suitable here.
7402 * The context lock guarantees that.
7404 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7405 lockdep_is_held(&event->ctx->lock));
7409 return __find_swevent_head(hlist, type, event_id);
7412 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7414 struct perf_sample_data *data,
7415 struct pt_regs *regs)
7417 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7418 struct perf_event *event;
7419 struct hlist_head *head;
7422 head = find_swevent_head_rcu(swhash, type, event_id);
7426 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7427 if (perf_swevent_match(event, type, event_id, data, regs))
7428 perf_swevent_event(event, nr, data, regs);
7434 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7436 int perf_swevent_get_recursion_context(void)
7438 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7440 return get_recursion_context(swhash->recursion);
7442 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7444 void perf_swevent_put_recursion_context(int rctx)
7446 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7448 put_recursion_context(swhash->recursion, rctx);
7451 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7453 struct perf_sample_data data;
7455 if (WARN_ON_ONCE(!regs))
7458 perf_sample_data_init(&data, addr, 0);
7459 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7462 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7466 preempt_disable_notrace();
7467 rctx = perf_swevent_get_recursion_context();
7468 if (unlikely(rctx < 0))
7471 ___perf_sw_event(event_id, nr, regs, addr);
7473 perf_swevent_put_recursion_context(rctx);
7475 preempt_enable_notrace();
7478 static void perf_swevent_read(struct perf_event *event)
7482 static int perf_swevent_add(struct perf_event *event, int flags)
7484 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7485 struct hw_perf_event *hwc = &event->hw;
7486 struct hlist_head *head;
7488 if (is_sampling_event(event)) {
7489 hwc->last_period = hwc->sample_period;
7490 perf_swevent_set_period(event);
7493 hwc->state = !(flags & PERF_EF_START);
7495 head = find_swevent_head(swhash, event);
7496 if (WARN_ON_ONCE(!head))
7499 hlist_add_head_rcu(&event->hlist_entry, head);
7500 perf_event_update_userpage(event);
7505 static void perf_swevent_del(struct perf_event *event, int flags)
7507 hlist_del_rcu(&event->hlist_entry);
7510 static void perf_swevent_start(struct perf_event *event, int flags)
7512 event->hw.state = 0;
7515 static void perf_swevent_stop(struct perf_event *event, int flags)
7517 event->hw.state = PERF_HES_STOPPED;
7520 /* Deref the hlist from the update side */
7521 static inline struct swevent_hlist *
7522 swevent_hlist_deref(struct swevent_htable *swhash)
7524 return rcu_dereference_protected(swhash->swevent_hlist,
7525 lockdep_is_held(&swhash->hlist_mutex));
7528 static void swevent_hlist_release(struct swevent_htable *swhash)
7530 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7535 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7536 kfree_rcu(hlist, rcu_head);
7539 static void swevent_hlist_put_cpu(int cpu)
7541 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7543 mutex_lock(&swhash->hlist_mutex);
7545 if (!--swhash->hlist_refcount)
7546 swevent_hlist_release(swhash);
7548 mutex_unlock(&swhash->hlist_mutex);
7551 static void swevent_hlist_put(void)
7555 for_each_possible_cpu(cpu)
7556 swevent_hlist_put_cpu(cpu);
7559 static int swevent_hlist_get_cpu(int cpu)
7561 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7564 mutex_lock(&swhash->hlist_mutex);
7565 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7566 struct swevent_hlist *hlist;
7568 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7573 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7575 swhash->hlist_refcount++;
7577 mutex_unlock(&swhash->hlist_mutex);
7582 static int swevent_hlist_get(void)
7584 int err, cpu, failed_cpu;
7587 for_each_possible_cpu(cpu) {
7588 err = swevent_hlist_get_cpu(cpu);
7598 for_each_possible_cpu(cpu) {
7599 if (cpu == failed_cpu)
7601 swevent_hlist_put_cpu(cpu);
7608 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7610 static void sw_perf_event_destroy(struct perf_event *event)
7612 u64 event_id = event->attr.config;
7614 WARN_ON(event->parent);
7616 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7617 swevent_hlist_put();
7620 static int perf_swevent_init(struct perf_event *event)
7622 u64 event_id = event->attr.config;
7624 if (event->attr.type != PERF_TYPE_SOFTWARE)
7628 * no branch sampling for software events
7630 if (has_branch_stack(event))
7634 case PERF_COUNT_SW_CPU_CLOCK:
7635 case PERF_COUNT_SW_TASK_CLOCK:
7642 if (event_id >= PERF_COUNT_SW_MAX)
7645 if (!event->parent) {
7648 err = swevent_hlist_get();
7652 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7653 event->destroy = sw_perf_event_destroy;
7659 static struct pmu perf_swevent = {
7660 .task_ctx_nr = perf_sw_context,
7662 .capabilities = PERF_PMU_CAP_NO_NMI,
7664 .event_init = perf_swevent_init,
7665 .add = perf_swevent_add,
7666 .del = perf_swevent_del,
7667 .start = perf_swevent_start,
7668 .stop = perf_swevent_stop,
7669 .read = perf_swevent_read,
7672 #ifdef CONFIG_EVENT_TRACING
7674 static int perf_tp_filter_match(struct perf_event *event,
7675 struct perf_sample_data *data)
7677 void *record = data->raw->frag.data;
7679 /* only top level events have filters set */
7681 event = event->parent;
7683 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7688 static int perf_tp_event_match(struct perf_event *event,
7689 struct perf_sample_data *data,
7690 struct pt_regs *regs)
7692 if (event->hw.state & PERF_HES_STOPPED)
7695 * All tracepoints are from kernel-space.
7697 if (event->attr.exclude_kernel)
7700 if (!perf_tp_filter_match(event, data))
7706 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7707 struct trace_event_call *call, u64 count,
7708 struct pt_regs *regs, struct hlist_head *head,
7709 struct task_struct *task)
7711 struct bpf_prog *prog = call->prog;
7714 *(struct pt_regs **)raw_data = regs;
7715 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7716 perf_swevent_put_recursion_context(rctx);
7720 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7723 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7725 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7726 struct pt_regs *regs, struct hlist_head *head, int rctx,
7727 struct task_struct *task)
7729 struct perf_sample_data data;
7730 struct perf_event *event;
7732 struct perf_raw_record raw = {
7739 perf_sample_data_init(&data, 0, 0);
7742 perf_trace_buf_update(record, event_type);
7744 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7745 if (perf_tp_event_match(event, &data, regs))
7746 perf_swevent_event(event, count, &data, regs);
7750 * If we got specified a target task, also iterate its context and
7751 * deliver this event there too.
7753 if (task && task != current) {
7754 struct perf_event_context *ctx;
7755 struct trace_entry *entry = record;
7758 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7762 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7763 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7765 if (event->attr.config != entry->type)
7767 if (perf_tp_event_match(event, &data, regs))
7768 perf_swevent_event(event, count, &data, regs);
7774 perf_swevent_put_recursion_context(rctx);
7776 EXPORT_SYMBOL_GPL(perf_tp_event);
7778 static void tp_perf_event_destroy(struct perf_event *event)
7780 perf_trace_destroy(event);
7783 static int perf_tp_event_init(struct perf_event *event)
7787 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7791 * no branch sampling for tracepoint events
7793 if (has_branch_stack(event))
7796 err = perf_trace_init(event);
7800 event->destroy = tp_perf_event_destroy;
7805 static struct pmu perf_tracepoint = {
7806 .task_ctx_nr = perf_sw_context,
7808 .event_init = perf_tp_event_init,
7809 .add = perf_trace_add,
7810 .del = perf_trace_del,
7811 .start = perf_swevent_start,
7812 .stop = perf_swevent_stop,
7813 .read = perf_swevent_read,
7816 static inline void perf_tp_register(void)
7818 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7821 static void perf_event_free_filter(struct perf_event *event)
7823 ftrace_profile_free_filter(event);
7826 #ifdef CONFIG_BPF_SYSCALL
7827 static void bpf_overflow_handler(struct perf_event *event,
7828 struct perf_sample_data *data,
7829 struct pt_regs *regs)
7831 struct bpf_perf_event_data_kern ctx = {
7838 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7841 ret = BPF_PROG_RUN(event->prog, &ctx);
7844 __this_cpu_dec(bpf_prog_active);
7849 event->orig_overflow_handler(event, data, regs);
7852 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7854 struct bpf_prog *prog;
7856 if (event->overflow_handler_context)
7857 /* hw breakpoint or kernel counter */
7863 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
7865 return PTR_ERR(prog);
7868 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
7869 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
7873 static void perf_event_free_bpf_handler(struct perf_event *event)
7875 struct bpf_prog *prog = event->prog;
7880 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
7885 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7889 static void perf_event_free_bpf_handler(struct perf_event *event)
7894 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7896 bool is_kprobe, is_tracepoint;
7897 struct bpf_prog *prog;
7899 if (event->attr.type == PERF_TYPE_HARDWARE ||
7900 event->attr.type == PERF_TYPE_SOFTWARE)
7901 return perf_event_set_bpf_handler(event, prog_fd);
7903 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7906 if (event->tp_event->prog)
7909 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7910 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7911 if (!is_kprobe && !is_tracepoint)
7912 /* bpf programs can only be attached to u/kprobe or tracepoint */
7915 prog = bpf_prog_get(prog_fd);
7917 return PTR_ERR(prog);
7919 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7920 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7921 /* valid fd, but invalid bpf program type */
7926 if (is_tracepoint) {
7927 int off = trace_event_get_offsets(event->tp_event);
7929 if (prog->aux->max_ctx_offset > off) {
7934 event->tp_event->prog = prog;
7939 static void perf_event_free_bpf_prog(struct perf_event *event)
7941 struct bpf_prog *prog;
7943 perf_event_free_bpf_handler(event);
7945 if (!event->tp_event)
7948 prog = event->tp_event->prog;
7950 event->tp_event->prog = NULL;
7957 static inline void perf_tp_register(void)
7961 static void perf_event_free_filter(struct perf_event *event)
7965 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7970 static void perf_event_free_bpf_prog(struct perf_event *event)
7973 #endif /* CONFIG_EVENT_TRACING */
7975 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7976 void perf_bp_event(struct perf_event *bp, void *data)
7978 struct perf_sample_data sample;
7979 struct pt_regs *regs = data;
7981 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7983 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7984 perf_swevent_event(bp, 1, &sample, regs);
7989 * Allocate a new address filter
7991 static struct perf_addr_filter *
7992 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7994 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7995 struct perf_addr_filter *filter;
7997 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8001 INIT_LIST_HEAD(&filter->entry);
8002 list_add_tail(&filter->entry, filters);
8007 static void free_filters_list(struct list_head *filters)
8009 struct perf_addr_filter *filter, *iter;
8011 list_for_each_entry_safe(filter, iter, filters, entry) {
8013 iput(filter->inode);
8014 list_del(&filter->entry);
8020 * Free existing address filters and optionally install new ones
8022 static void perf_addr_filters_splice(struct perf_event *event,
8023 struct list_head *head)
8025 unsigned long flags;
8028 if (!has_addr_filter(event))
8031 /* don't bother with children, they don't have their own filters */
8035 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8037 list_splice_init(&event->addr_filters.list, &list);
8039 list_splice(head, &event->addr_filters.list);
8041 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8043 free_filters_list(&list);
8047 * Scan through mm's vmas and see if one of them matches the
8048 * @filter; if so, adjust filter's address range.
8049 * Called with mm::mmap_sem down for reading.
8051 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8052 struct mm_struct *mm)
8054 struct vm_area_struct *vma;
8056 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8057 struct file *file = vma->vm_file;
8058 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8059 unsigned long vma_size = vma->vm_end - vma->vm_start;
8064 if (!perf_addr_filter_match(filter, file, off, vma_size))
8067 return vma->vm_start;
8074 * Update event's address range filters based on the
8075 * task's existing mappings, if any.
8077 static void perf_event_addr_filters_apply(struct perf_event *event)
8079 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8080 struct task_struct *task = READ_ONCE(event->ctx->task);
8081 struct perf_addr_filter *filter;
8082 struct mm_struct *mm = NULL;
8083 unsigned int count = 0;
8084 unsigned long flags;
8087 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8088 * will stop on the parent's child_mutex that our caller is also holding
8090 if (task == TASK_TOMBSTONE)
8093 mm = get_task_mm(event->ctx->task);
8097 down_read(&mm->mmap_sem);
8099 raw_spin_lock_irqsave(&ifh->lock, flags);
8100 list_for_each_entry(filter, &ifh->list, entry) {
8101 event->addr_filters_offs[count] = 0;
8104 * Adjust base offset if the filter is associated to a binary
8105 * that needs to be mapped:
8108 event->addr_filters_offs[count] =
8109 perf_addr_filter_apply(filter, mm);
8114 event->addr_filters_gen++;
8115 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8117 up_read(&mm->mmap_sem);
8122 perf_event_stop(event, 1);
8126 * Address range filtering: limiting the data to certain
8127 * instruction address ranges. Filters are ioctl()ed to us from
8128 * userspace as ascii strings.
8130 * Filter string format:
8133 * where ACTION is one of the
8134 * * "filter": limit the trace to this region
8135 * * "start": start tracing from this address
8136 * * "stop": stop tracing at this address/region;
8138 * * for kernel addresses: <start address>[/<size>]
8139 * * for object files: <start address>[/<size>]@</path/to/object/file>
8141 * if <size> is not specified, the range is treated as a single address.
8155 IF_STATE_ACTION = 0,
8160 static const match_table_t if_tokens = {
8161 { IF_ACT_FILTER, "filter" },
8162 { IF_ACT_START, "start" },
8163 { IF_ACT_STOP, "stop" },
8164 { IF_SRC_FILE, "%u/%u@%s" },
8165 { IF_SRC_KERNEL, "%u/%u" },
8166 { IF_SRC_FILEADDR, "%u@%s" },
8167 { IF_SRC_KERNELADDR, "%u" },
8168 { IF_ACT_NONE, NULL },
8172 * Address filter string parser
8175 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8176 struct list_head *filters)
8178 struct perf_addr_filter *filter = NULL;
8179 char *start, *orig, *filename = NULL;
8181 substring_t args[MAX_OPT_ARGS];
8182 int state = IF_STATE_ACTION, token;
8183 unsigned int kernel = 0;
8186 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8190 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8196 /* filter definition begins */
8197 if (state == IF_STATE_ACTION) {
8198 filter = perf_addr_filter_new(event, filters);
8203 token = match_token(start, if_tokens, args);
8210 if (state != IF_STATE_ACTION)
8213 state = IF_STATE_SOURCE;
8216 case IF_SRC_KERNELADDR:
8220 case IF_SRC_FILEADDR:
8222 if (state != IF_STATE_SOURCE)
8225 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8229 ret = kstrtoul(args[0].from, 0, &filter->offset);
8233 if (filter->range) {
8235 ret = kstrtoul(args[1].from, 0, &filter->size);
8240 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8241 int fpos = filter->range ? 2 : 1;
8243 filename = match_strdup(&args[fpos]);
8250 state = IF_STATE_END;
8258 * Filter definition is fully parsed, validate and install it.
8259 * Make sure that it doesn't contradict itself or the event's
8262 if (state == IF_STATE_END) {
8264 if (kernel && event->attr.exclude_kernel)
8271 /* look up the path and grab its inode */
8272 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8274 goto fail_free_name;
8276 filter->inode = igrab(d_inode(path.dentry));
8282 if (!filter->inode ||
8283 !S_ISREG(filter->inode->i_mode))
8284 /* free_filters_list() will iput() */
8288 /* ready to consume more filters */
8289 state = IF_STATE_ACTION;
8294 if (state != IF_STATE_ACTION)
8304 free_filters_list(filters);
8311 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8317 * Since this is called in perf_ioctl() path, we're already holding
8320 lockdep_assert_held(&event->ctx->mutex);
8322 if (WARN_ON_ONCE(event->parent))
8326 * For now, we only support filtering in per-task events; doing so
8327 * for CPU-wide events requires additional context switching trickery,
8328 * since same object code will be mapped at different virtual
8329 * addresses in different processes.
8331 if (!event->ctx->task)
8334 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8338 ret = event->pmu->addr_filters_validate(&filters);
8340 free_filters_list(&filters);
8344 /* remove existing filters, if any */
8345 perf_addr_filters_splice(event, &filters);
8347 /* install new filters */
8348 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8353 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8358 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8359 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8360 !has_addr_filter(event))
8363 filter_str = strndup_user(arg, PAGE_SIZE);
8364 if (IS_ERR(filter_str))
8365 return PTR_ERR(filter_str);
8367 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8368 event->attr.type == PERF_TYPE_TRACEPOINT)
8369 ret = ftrace_profile_set_filter(event, event->attr.config,
8371 else if (has_addr_filter(event))
8372 ret = perf_event_set_addr_filter(event, filter_str);
8379 * hrtimer based swevent callback
8382 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8384 enum hrtimer_restart ret = HRTIMER_RESTART;
8385 struct perf_sample_data data;
8386 struct pt_regs *regs;
8387 struct perf_event *event;
8390 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8392 if (event->state != PERF_EVENT_STATE_ACTIVE)
8393 return HRTIMER_NORESTART;
8395 event->pmu->read(event);
8397 perf_sample_data_init(&data, 0, event->hw.last_period);
8398 regs = get_irq_regs();
8400 if (regs && !perf_exclude_event(event, regs)) {
8401 if (!(event->attr.exclude_idle && is_idle_task(current)))
8402 if (__perf_event_overflow(event, 1, &data, regs))
8403 ret = HRTIMER_NORESTART;
8406 period = max_t(u64, 10000, event->hw.sample_period);
8407 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8412 static void perf_swevent_start_hrtimer(struct perf_event *event)
8414 struct hw_perf_event *hwc = &event->hw;
8417 if (!is_sampling_event(event))
8420 period = local64_read(&hwc->period_left);
8425 local64_set(&hwc->period_left, 0);
8427 period = max_t(u64, 10000, hwc->sample_period);
8429 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8430 HRTIMER_MODE_REL_PINNED);
8433 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8435 struct hw_perf_event *hwc = &event->hw;
8437 if (is_sampling_event(event)) {
8438 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8439 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8441 hrtimer_cancel(&hwc->hrtimer);
8445 static void perf_swevent_init_hrtimer(struct perf_event *event)
8447 struct hw_perf_event *hwc = &event->hw;
8449 if (!is_sampling_event(event))
8452 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8453 hwc->hrtimer.function = perf_swevent_hrtimer;
8456 * Since hrtimers have a fixed rate, we can do a static freq->period
8457 * mapping and avoid the whole period adjust feedback stuff.
8459 if (event->attr.freq) {
8460 long freq = event->attr.sample_freq;
8462 event->attr.sample_period = NSEC_PER_SEC / freq;
8463 hwc->sample_period = event->attr.sample_period;
8464 local64_set(&hwc->period_left, hwc->sample_period);
8465 hwc->last_period = hwc->sample_period;
8466 event->attr.freq = 0;
8471 * Software event: cpu wall time clock
8474 static void cpu_clock_event_update(struct perf_event *event)
8479 now = local_clock();
8480 prev = local64_xchg(&event->hw.prev_count, now);
8481 local64_add(now - prev, &event->count);
8484 static void cpu_clock_event_start(struct perf_event *event, int flags)
8486 local64_set(&event->hw.prev_count, local_clock());
8487 perf_swevent_start_hrtimer(event);
8490 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8492 perf_swevent_cancel_hrtimer(event);
8493 cpu_clock_event_update(event);
8496 static int cpu_clock_event_add(struct perf_event *event, int flags)
8498 if (flags & PERF_EF_START)
8499 cpu_clock_event_start(event, flags);
8500 perf_event_update_userpage(event);
8505 static void cpu_clock_event_del(struct perf_event *event, int flags)
8507 cpu_clock_event_stop(event, flags);
8510 static void cpu_clock_event_read(struct perf_event *event)
8512 cpu_clock_event_update(event);
8515 static int cpu_clock_event_init(struct perf_event *event)
8517 if (event->attr.type != PERF_TYPE_SOFTWARE)
8520 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8524 * no branch sampling for software events
8526 if (has_branch_stack(event))
8529 perf_swevent_init_hrtimer(event);
8534 static struct pmu perf_cpu_clock = {
8535 .task_ctx_nr = perf_sw_context,
8537 .capabilities = PERF_PMU_CAP_NO_NMI,
8539 .event_init = cpu_clock_event_init,
8540 .add = cpu_clock_event_add,
8541 .del = cpu_clock_event_del,
8542 .start = cpu_clock_event_start,
8543 .stop = cpu_clock_event_stop,
8544 .read = cpu_clock_event_read,
8548 * Software event: task time clock
8551 static void task_clock_event_update(struct perf_event *event, u64 now)
8556 prev = local64_xchg(&event->hw.prev_count, now);
8558 local64_add(delta, &event->count);
8561 static void task_clock_event_start(struct perf_event *event, int flags)
8563 local64_set(&event->hw.prev_count, event->ctx->time);
8564 perf_swevent_start_hrtimer(event);
8567 static void task_clock_event_stop(struct perf_event *event, int flags)
8569 perf_swevent_cancel_hrtimer(event);
8570 task_clock_event_update(event, event->ctx->time);
8573 static int task_clock_event_add(struct perf_event *event, int flags)
8575 if (flags & PERF_EF_START)
8576 task_clock_event_start(event, flags);
8577 perf_event_update_userpage(event);
8582 static void task_clock_event_del(struct perf_event *event, int flags)
8584 task_clock_event_stop(event, PERF_EF_UPDATE);
8587 static void task_clock_event_read(struct perf_event *event)
8589 u64 now = perf_clock();
8590 u64 delta = now - event->ctx->timestamp;
8591 u64 time = event->ctx->time + delta;
8593 task_clock_event_update(event, time);
8596 static int task_clock_event_init(struct perf_event *event)
8598 if (event->attr.type != PERF_TYPE_SOFTWARE)
8601 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8605 * no branch sampling for software events
8607 if (has_branch_stack(event))
8610 perf_swevent_init_hrtimer(event);
8615 static struct pmu perf_task_clock = {
8616 .task_ctx_nr = perf_sw_context,
8618 .capabilities = PERF_PMU_CAP_NO_NMI,
8620 .event_init = task_clock_event_init,
8621 .add = task_clock_event_add,
8622 .del = task_clock_event_del,
8623 .start = task_clock_event_start,
8624 .stop = task_clock_event_stop,
8625 .read = task_clock_event_read,
8628 static void perf_pmu_nop_void(struct pmu *pmu)
8632 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8636 static int perf_pmu_nop_int(struct pmu *pmu)
8641 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8643 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8645 __this_cpu_write(nop_txn_flags, flags);
8647 if (flags & ~PERF_PMU_TXN_ADD)
8650 perf_pmu_disable(pmu);
8653 static int perf_pmu_commit_txn(struct pmu *pmu)
8655 unsigned int flags = __this_cpu_read(nop_txn_flags);
8657 __this_cpu_write(nop_txn_flags, 0);
8659 if (flags & ~PERF_PMU_TXN_ADD)
8662 perf_pmu_enable(pmu);
8666 static void perf_pmu_cancel_txn(struct pmu *pmu)
8668 unsigned int flags = __this_cpu_read(nop_txn_flags);
8670 __this_cpu_write(nop_txn_flags, 0);
8672 if (flags & ~PERF_PMU_TXN_ADD)
8675 perf_pmu_enable(pmu);
8678 static int perf_event_idx_default(struct perf_event *event)
8684 * Ensures all contexts with the same task_ctx_nr have the same
8685 * pmu_cpu_context too.
8687 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8694 list_for_each_entry(pmu, &pmus, entry) {
8695 if (pmu->task_ctx_nr == ctxn)
8696 return pmu->pmu_cpu_context;
8702 static void free_pmu_context(struct pmu *pmu)
8704 mutex_lock(&pmus_lock);
8705 free_percpu(pmu->pmu_cpu_context);
8706 mutex_unlock(&pmus_lock);
8710 * Let userspace know that this PMU supports address range filtering:
8712 static ssize_t nr_addr_filters_show(struct device *dev,
8713 struct device_attribute *attr,
8716 struct pmu *pmu = dev_get_drvdata(dev);
8718 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8720 DEVICE_ATTR_RO(nr_addr_filters);
8722 static struct idr pmu_idr;
8725 type_show(struct device *dev, struct device_attribute *attr, char *page)
8727 struct pmu *pmu = dev_get_drvdata(dev);
8729 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8731 static DEVICE_ATTR_RO(type);
8734 perf_event_mux_interval_ms_show(struct device *dev,
8735 struct device_attribute *attr,
8738 struct pmu *pmu = dev_get_drvdata(dev);
8740 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8743 static DEFINE_MUTEX(mux_interval_mutex);
8746 perf_event_mux_interval_ms_store(struct device *dev,
8747 struct device_attribute *attr,
8748 const char *buf, size_t count)
8750 struct pmu *pmu = dev_get_drvdata(dev);
8751 int timer, cpu, ret;
8753 ret = kstrtoint(buf, 0, &timer);
8760 /* same value, noting to do */
8761 if (timer == pmu->hrtimer_interval_ms)
8764 mutex_lock(&mux_interval_mutex);
8765 pmu->hrtimer_interval_ms = timer;
8767 /* update all cpuctx for this PMU */
8769 for_each_online_cpu(cpu) {
8770 struct perf_cpu_context *cpuctx;
8771 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8772 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8774 cpu_function_call(cpu,
8775 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8778 mutex_unlock(&mux_interval_mutex);
8782 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8784 static struct attribute *pmu_dev_attrs[] = {
8785 &dev_attr_type.attr,
8786 &dev_attr_perf_event_mux_interval_ms.attr,
8789 ATTRIBUTE_GROUPS(pmu_dev);
8791 static int pmu_bus_running;
8792 static struct bus_type pmu_bus = {
8793 .name = "event_source",
8794 .dev_groups = pmu_dev_groups,
8797 static void pmu_dev_release(struct device *dev)
8802 static int pmu_dev_alloc(struct pmu *pmu)
8806 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8810 pmu->dev->groups = pmu->attr_groups;
8811 device_initialize(pmu->dev);
8812 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8816 dev_set_drvdata(pmu->dev, pmu);
8817 pmu->dev->bus = &pmu_bus;
8818 pmu->dev->release = pmu_dev_release;
8819 ret = device_add(pmu->dev);
8823 /* For PMUs with address filters, throw in an extra attribute: */
8824 if (pmu->nr_addr_filters)
8825 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8834 device_del(pmu->dev);
8837 put_device(pmu->dev);
8841 static struct lock_class_key cpuctx_mutex;
8842 static struct lock_class_key cpuctx_lock;
8844 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8848 mutex_lock(&pmus_lock);
8850 pmu->pmu_disable_count = alloc_percpu(int);
8851 if (!pmu->pmu_disable_count)
8860 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8868 if (pmu_bus_running) {
8869 ret = pmu_dev_alloc(pmu);
8875 if (pmu->task_ctx_nr == perf_hw_context) {
8876 static int hw_context_taken = 0;
8879 * Other than systems with heterogeneous CPUs, it never makes
8880 * sense for two PMUs to share perf_hw_context. PMUs which are
8881 * uncore must use perf_invalid_context.
8883 if (WARN_ON_ONCE(hw_context_taken &&
8884 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8885 pmu->task_ctx_nr = perf_invalid_context;
8887 hw_context_taken = 1;
8890 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8891 if (pmu->pmu_cpu_context)
8892 goto got_cpu_context;
8895 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8896 if (!pmu->pmu_cpu_context)
8899 for_each_possible_cpu(cpu) {
8900 struct perf_cpu_context *cpuctx;
8902 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8903 __perf_event_init_context(&cpuctx->ctx);
8904 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8905 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8906 cpuctx->ctx.pmu = pmu;
8908 __perf_mux_hrtimer_init(cpuctx, cpu);
8912 if (!pmu->start_txn) {
8913 if (pmu->pmu_enable) {
8915 * If we have pmu_enable/pmu_disable calls, install
8916 * transaction stubs that use that to try and batch
8917 * hardware accesses.
8919 pmu->start_txn = perf_pmu_start_txn;
8920 pmu->commit_txn = perf_pmu_commit_txn;
8921 pmu->cancel_txn = perf_pmu_cancel_txn;
8923 pmu->start_txn = perf_pmu_nop_txn;
8924 pmu->commit_txn = perf_pmu_nop_int;
8925 pmu->cancel_txn = perf_pmu_nop_void;
8929 if (!pmu->pmu_enable) {
8930 pmu->pmu_enable = perf_pmu_nop_void;
8931 pmu->pmu_disable = perf_pmu_nop_void;
8934 if (!pmu->event_idx)
8935 pmu->event_idx = perf_event_idx_default;
8937 list_add_rcu(&pmu->entry, &pmus);
8938 atomic_set(&pmu->exclusive_cnt, 0);
8941 mutex_unlock(&pmus_lock);
8946 device_del(pmu->dev);
8947 put_device(pmu->dev);
8950 if (pmu->type >= PERF_TYPE_MAX)
8951 idr_remove(&pmu_idr, pmu->type);
8954 free_percpu(pmu->pmu_disable_count);
8957 EXPORT_SYMBOL_GPL(perf_pmu_register);
8959 void perf_pmu_unregister(struct pmu *pmu)
8963 mutex_lock(&pmus_lock);
8964 remove_device = pmu_bus_running;
8965 list_del_rcu(&pmu->entry);
8966 mutex_unlock(&pmus_lock);
8969 * We dereference the pmu list under both SRCU and regular RCU, so
8970 * synchronize against both of those.
8972 synchronize_srcu(&pmus_srcu);
8975 free_percpu(pmu->pmu_disable_count);
8976 if (pmu->type >= PERF_TYPE_MAX)
8977 idr_remove(&pmu_idr, pmu->type);
8978 if (remove_device) {
8979 if (pmu->nr_addr_filters)
8980 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8981 device_del(pmu->dev);
8982 put_device(pmu->dev);
8984 free_pmu_context(pmu);
8986 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8988 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8990 struct perf_event_context *ctx = NULL;
8993 if (!try_module_get(pmu->module))
8996 if (event->group_leader != event) {
8998 * This ctx->mutex can nest when we're called through
8999 * inheritance. See the perf_event_ctx_lock_nested() comment.
9001 ctx = perf_event_ctx_lock_nested(event->group_leader,
9002 SINGLE_DEPTH_NESTING);
9007 ret = pmu->event_init(event);
9010 perf_event_ctx_unlock(event->group_leader, ctx);
9013 module_put(pmu->module);
9018 static struct pmu *perf_init_event(struct perf_event *event)
9020 struct pmu *pmu = NULL;
9024 idx = srcu_read_lock(&pmus_srcu);
9026 /* Try parent's PMU first: */
9027 if (event->parent && event->parent->pmu) {
9028 pmu = event->parent->pmu;
9029 ret = perf_try_init_event(pmu, event);
9035 pmu = idr_find(&pmu_idr, event->attr.type);
9038 ret = perf_try_init_event(pmu, event);
9044 list_for_each_entry_rcu(pmu, &pmus, entry) {
9045 ret = perf_try_init_event(pmu, event);
9049 if (ret != -ENOENT) {
9054 pmu = ERR_PTR(-ENOENT);
9056 srcu_read_unlock(&pmus_srcu, idx);
9061 static void attach_sb_event(struct perf_event *event)
9063 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9065 raw_spin_lock(&pel->lock);
9066 list_add_rcu(&event->sb_list, &pel->list);
9067 raw_spin_unlock(&pel->lock);
9071 * We keep a list of all !task (and therefore per-cpu) events
9072 * that need to receive side-band records.
9074 * This avoids having to scan all the various PMU per-cpu contexts
9077 static void account_pmu_sb_event(struct perf_event *event)
9079 if (is_sb_event(event))
9080 attach_sb_event(event);
9083 static void account_event_cpu(struct perf_event *event, int cpu)
9088 if (is_cgroup_event(event))
9089 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9092 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9093 static void account_freq_event_nohz(void)
9095 #ifdef CONFIG_NO_HZ_FULL
9096 /* Lock so we don't race with concurrent unaccount */
9097 spin_lock(&nr_freq_lock);
9098 if (atomic_inc_return(&nr_freq_events) == 1)
9099 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9100 spin_unlock(&nr_freq_lock);
9104 static void account_freq_event(void)
9106 if (tick_nohz_full_enabled())
9107 account_freq_event_nohz();
9109 atomic_inc(&nr_freq_events);
9113 static void account_event(struct perf_event *event)
9120 if (event->attach_state & PERF_ATTACH_TASK)
9122 if (event->attr.mmap || event->attr.mmap_data)
9123 atomic_inc(&nr_mmap_events);
9124 if (event->attr.comm)
9125 atomic_inc(&nr_comm_events);
9126 if (event->attr.task)
9127 atomic_inc(&nr_task_events);
9128 if (event->attr.freq)
9129 account_freq_event();
9130 if (event->attr.context_switch) {
9131 atomic_inc(&nr_switch_events);
9134 if (has_branch_stack(event))
9136 if (is_cgroup_event(event))
9140 if (atomic_inc_not_zero(&perf_sched_count))
9143 mutex_lock(&perf_sched_mutex);
9144 if (!atomic_read(&perf_sched_count)) {
9145 static_branch_enable(&perf_sched_events);
9147 * Guarantee that all CPUs observe they key change and
9148 * call the perf scheduling hooks before proceeding to
9149 * install events that need them.
9151 synchronize_sched();
9154 * Now that we have waited for the sync_sched(), allow further
9155 * increments to by-pass the mutex.
9157 atomic_inc(&perf_sched_count);
9158 mutex_unlock(&perf_sched_mutex);
9162 account_event_cpu(event, event->cpu);
9164 account_pmu_sb_event(event);
9168 * Allocate and initialize a event structure
9170 static struct perf_event *
9171 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9172 struct task_struct *task,
9173 struct perf_event *group_leader,
9174 struct perf_event *parent_event,
9175 perf_overflow_handler_t overflow_handler,
9176 void *context, int cgroup_fd)
9179 struct perf_event *event;
9180 struct hw_perf_event *hwc;
9183 if ((unsigned)cpu >= nr_cpu_ids) {
9184 if (!task || cpu != -1)
9185 return ERR_PTR(-EINVAL);
9188 event = kzalloc(sizeof(*event), GFP_KERNEL);
9190 return ERR_PTR(-ENOMEM);
9193 * Single events are their own group leaders, with an
9194 * empty sibling list:
9197 group_leader = event;
9199 mutex_init(&event->child_mutex);
9200 INIT_LIST_HEAD(&event->child_list);
9202 INIT_LIST_HEAD(&event->group_entry);
9203 INIT_LIST_HEAD(&event->event_entry);
9204 INIT_LIST_HEAD(&event->sibling_list);
9205 INIT_LIST_HEAD(&event->rb_entry);
9206 INIT_LIST_HEAD(&event->active_entry);
9207 INIT_LIST_HEAD(&event->addr_filters.list);
9208 INIT_HLIST_NODE(&event->hlist_entry);
9211 init_waitqueue_head(&event->waitq);
9212 init_irq_work(&event->pending, perf_pending_event);
9214 mutex_init(&event->mmap_mutex);
9215 raw_spin_lock_init(&event->addr_filters.lock);
9217 atomic_long_set(&event->refcount, 1);
9219 event->attr = *attr;
9220 event->group_leader = group_leader;
9224 event->parent = parent_event;
9226 event->ns = get_pid_ns(task_active_pid_ns(current));
9227 event->id = atomic64_inc_return(&perf_event_id);
9229 event->state = PERF_EVENT_STATE_INACTIVE;
9232 event->attach_state = PERF_ATTACH_TASK;
9234 * XXX pmu::event_init needs to know what task to account to
9235 * and we cannot use the ctx information because we need the
9236 * pmu before we get a ctx.
9238 event->hw.target = task;
9241 event->clock = &local_clock;
9243 event->clock = parent_event->clock;
9245 if (!overflow_handler && parent_event) {
9246 overflow_handler = parent_event->overflow_handler;
9247 context = parent_event->overflow_handler_context;
9248 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9249 if (overflow_handler == bpf_overflow_handler) {
9250 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9253 err = PTR_ERR(prog);
9257 event->orig_overflow_handler =
9258 parent_event->orig_overflow_handler;
9263 if (overflow_handler) {
9264 event->overflow_handler = overflow_handler;
9265 event->overflow_handler_context = context;
9266 } else if (is_write_backward(event)){
9267 event->overflow_handler = perf_event_output_backward;
9268 event->overflow_handler_context = NULL;
9270 event->overflow_handler = perf_event_output_forward;
9271 event->overflow_handler_context = NULL;
9274 perf_event__state_init(event);
9279 hwc->sample_period = attr->sample_period;
9280 if (attr->freq && attr->sample_freq)
9281 hwc->sample_period = 1;
9282 hwc->last_period = hwc->sample_period;
9284 local64_set(&hwc->period_left, hwc->sample_period);
9287 * we currently do not support PERF_FORMAT_GROUP on inherited events
9289 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9292 if (!has_branch_stack(event))
9293 event->attr.branch_sample_type = 0;
9295 if (cgroup_fd != -1) {
9296 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9301 pmu = perf_init_event(event);
9304 else if (IS_ERR(pmu)) {
9309 err = exclusive_event_init(event);
9313 if (has_addr_filter(event)) {
9314 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9315 sizeof(unsigned long),
9317 if (!event->addr_filters_offs)
9320 /* force hw sync on the address filters */
9321 event->addr_filters_gen = 1;
9324 if (!event->parent) {
9325 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9326 err = get_callchain_buffers(attr->sample_max_stack);
9328 goto err_addr_filters;
9332 /* symmetric to unaccount_event() in _free_event() */
9333 account_event(event);
9338 kfree(event->addr_filters_offs);
9341 exclusive_event_destroy(event);
9345 event->destroy(event);
9346 module_put(pmu->module);
9348 if (is_cgroup_event(event))
9349 perf_detach_cgroup(event);
9351 put_pid_ns(event->ns);
9354 return ERR_PTR(err);
9357 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9358 struct perf_event_attr *attr)
9363 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9367 * zero the full structure, so that a short copy will be nice.
9369 memset(attr, 0, sizeof(*attr));
9371 ret = get_user(size, &uattr->size);
9375 if (size > PAGE_SIZE) /* silly large */
9378 if (!size) /* abi compat */
9379 size = PERF_ATTR_SIZE_VER0;
9381 if (size < PERF_ATTR_SIZE_VER0)
9385 * If we're handed a bigger struct than we know of,
9386 * ensure all the unknown bits are 0 - i.e. new
9387 * user-space does not rely on any kernel feature
9388 * extensions we dont know about yet.
9390 if (size > sizeof(*attr)) {
9391 unsigned char __user *addr;
9392 unsigned char __user *end;
9395 addr = (void __user *)uattr + sizeof(*attr);
9396 end = (void __user *)uattr + size;
9398 for (; addr < end; addr++) {
9399 ret = get_user(val, addr);
9405 size = sizeof(*attr);
9408 ret = copy_from_user(attr, uattr, size);
9412 if (attr->__reserved_1)
9415 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9418 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9421 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9422 u64 mask = attr->branch_sample_type;
9424 /* only using defined bits */
9425 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9428 /* at least one branch bit must be set */
9429 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9432 /* propagate priv level, when not set for branch */
9433 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9435 /* exclude_kernel checked on syscall entry */
9436 if (!attr->exclude_kernel)
9437 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9439 if (!attr->exclude_user)
9440 mask |= PERF_SAMPLE_BRANCH_USER;
9442 if (!attr->exclude_hv)
9443 mask |= PERF_SAMPLE_BRANCH_HV;
9445 * adjust user setting (for HW filter setup)
9447 attr->branch_sample_type = mask;
9449 /* privileged levels capture (kernel, hv): check permissions */
9450 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9451 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9455 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9456 ret = perf_reg_validate(attr->sample_regs_user);
9461 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9462 if (!arch_perf_have_user_stack_dump())
9466 * We have __u32 type for the size, but so far
9467 * we can only use __u16 as maximum due to the
9468 * __u16 sample size limit.
9470 if (attr->sample_stack_user >= USHRT_MAX)
9472 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9476 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9477 ret = perf_reg_validate(attr->sample_regs_intr);
9482 put_user(sizeof(*attr), &uattr->size);
9488 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9490 struct ring_buffer *rb = NULL;
9496 /* don't allow circular references */
9497 if (event == output_event)
9501 * Don't allow cross-cpu buffers
9503 if (output_event->cpu != event->cpu)
9507 * If its not a per-cpu rb, it must be the same task.
9509 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9513 * Mixing clocks in the same buffer is trouble you don't need.
9515 if (output_event->clock != event->clock)
9519 * Either writing ring buffer from beginning or from end.
9520 * Mixing is not allowed.
9522 if (is_write_backward(output_event) != is_write_backward(event))
9526 * If both events generate aux data, they must be on the same PMU
9528 if (has_aux(event) && has_aux(output_event) &&
9529 event->pmu != output_event->pmu)
9533 mutex_lock(&event->mmap_mutex);
9534 /* Can't redirect output if we've got an active mmap() */
9535 if (atomic_read(&event->mmap_count))
9539 /* get the rb we want to redirect to */
9540 rb = ring_buffer_get(output_event);
9545 ring_buffer_attach(event, rb);
9549 mutex_unlock(&event->mmap_mutex);
9555 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9561 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9564 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9566 bool nmi_safe = false;
9569 case CLOCK_MONOTONIC:
9570 event->clock = &ktime_get_mono_fast_ns;
9574 case CLOCK_MONOTONIC_RAW:
9575 event->clock = &ktime_get_raw_fast_ns;
9579 case CLOCK_REALTIME:
9580 event->clock = &ktime_get_real_ns;
9583 case CLOCK_BOOTTIME:
9584 event->clock = &ktime_get_boot_ns;
9588 event->clock = &ktime_get_tai_ns;
9595 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9602 * Variation on perf_event_ctx_lock_nested(), except we take two context
9605 static struct perf_event_context *
9606 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9607 struct perf_event_context *ctx)
9609 struct perf_event_context *gctx;
9613 gctx = READ_ONCE(group_leader->ctx);
9614 if (!atomic_inc_not_zero(&gctx->refcount)) {
9620 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9622 if (group_leader->ctx != gctx) {
9623 mutex_unlock(&ctx->mutex);
9624 mutex_unlock(&gctx->mutex);
9633 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9635 * @attr_uptr: event_id type attributes for monitoring/sampling
9638 * @group_fd: group leader event fd
9640 SYSCALL_DEFINE5(perf_event_open,
9641 struct perf_event_attr __user *, attr_uptr,
9642 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9644 struct perf_event *group_leader = NULL, *output_event = NULL;
9645 struct perf_event *event, *sibling;
9646 struct perf_event_attr attr;
9647 struct perf_event_context *ctx, *uninitialized_var(gctx);
9648 struct file *event_file = NULL;
9649 struct fd group = {NULL, 0};
9650 struct task_struct *task = NULL;
9655 int f_flags = O_RDWR;
9658 /* for future expandability... */
9659 if (flags & ~PERF_FLAG_ALL)
9662 err = perf_copy_attr(attr_uptr, &attr);
9666 if (!attr.exclude_kernel) {
9667 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9672 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9675 if (attr.sample_period & (1ULL << 63))
9679 if (!attr.sample_max_stack)
9680 attr.sample_max_stack = sysctl_perf_event_max_stack;
9683 * In cgroup mode, the pid argument is used to pass the fd
9684 * opened to the cgroup directory in cgroupfs. The cpu argument
9685 * designates the cpu on which to monitor threads from that
9688 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9691 if (flags & PERF_FLAG_FD_CLOEXEC)
9692 f_flags |= O_CLOEXEC;
9694 event_fd = get_unused_fd_flags(f_flags);
9698 if (group_fd != -1) {
9699 err = perf_fget_light(group_fd, &group);
9702 group_leader = group.file->private_data;
9703 if (flags & PERF_FLAG_FD_OUTPUT)
9704 output_event = group_leader;
9705 if (flags & PERF_FLAG_FD_NO_GROUP)
9706 group_leader = NULL;
9709 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9710 task = find_lively_task_by_vpid(pid);
9712 err = PTR_ERR(task);
9717 if (task && group_leader &&
9718 group_leader->attr.inherit != attr.inherit) {
9726 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9731 * Reuse ptrace permission checks for now.
9733 * We must hold cred_guard_mutex across this and any potential
9734 * perf_install_in_context() call for this new event to
9735 * serialize against exec() altering our credentials (and the
9736 * perf_event_exit_task() that could imply).
9739 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9743 if (flags & PERF_FLAG_PID_CGROUP)
9746 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9747 NULL, NULL, cgroup_fd);
9748 if (IS_ERR(event)) {
9749 err = PTR_ERR(event);
9753 if (is_sampling_event(event)) {
9754 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9761 * Special case software events and allow them to be part of
9762 * any hardware group.
9766 if (attr.use_clockid) {
9767 err = perf_event_set_clock(event, attr.clockid);
9772 if (pmu->task_ctx_nr == perf_sw_context)
9773 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9776 (is_software_event(event) != is_software_event(group_leader))) {
9777 if (is_software_event(event)) {
9779 * If event and group_leader are not both a software
9780 * event, and event is, then group leader is not.
9782 * Allow the addition of software events to !software
9783 * groups, this is safe because software events never
9786 pmu = group_leader->pmu;
9787 } else if (is_software_event(group_leader) &&
9788 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9790 * In case the group is a pure software group, and we
9791 * try to add a hardware event, move the whole group to
9792 * the hardware context.
9799 * Get the target context (task or percpu):
9801 ctx = find_get_context(pmu, task, event);
9807 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9813 * Look up the group leader (we will attach this event to it):
9819 * Do not allow a recursive hierarchy (this new sibling
9820 * becoming part of another group-sibling):
9822 if (group_leader->group_leader != group_leader)
9825 /* All events in a group should have the same clock */
9826 if (group_leader->clock != event->clock)
9830 * Do not allow to attach to a group in a different
9831 * task or CPU context:
9835 * Make sure we're both on the same task, or both
9838 if (group_leader->ctx->task != ctx->task)
9842 * Make sure we're both events for the same CPU;
9843 * grouping events for different CPUs is broken; since
9844 * you can never concurrently schedule them anyhow.
9846 if (group_leader->cpu != event->cpu)
9849 if (group_leader->ctx != ctx)
9854 * Only a group leader can be exclusive or pinned
9856 if (attr.exclusive || attr.pinned)
9861 err = perf_event_set_output(event, output_event);
9866 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9868 if (IS_ERR(event_file)) {
9869 err = PTR_ERR(event_file);
9875 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
9877 if (gctx->task == TASK_TOMBSTONE) {
9883 * Check if we raced against another sys_perf_event_open() call
9884 * moving the software group underneath us.
9886 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9888 * If someone moved the group out from under us, check
9889 * if this new event wound up on the same ctx, if so
9890 * its the regular !move_group case, otherwise fail.
9896 perf_event_ctx_unlock(group_leader, gctx);
9901 mutex_lock(&ctx->mutex);
9904 if (ctx->task == TASK_TOMBSTONE) {
9909 if (!perf_event_validate_size(event)) {
9915 * Must be under the same ctx::mutex as perf_install_in_context(),
9916 * because we need to serialize with concurrent event creation.
9918 if (!exclusive_event_installable(event, ctx)) {
9919 /* exclusive and group stuff are assumed mutually exclusive */
9920 WARN_ON_ONCE(move_group);
9926 WARN_ON_ONCE(ctx->parent_ctx);
9929 * This is the point on no return; we cannot fail hereafter. This is
9930 * where we start modifying current state.
9935 * See perf_event_ctx_lock() for comments on the details
9936 * of swizzling perf_event::ctx.
9938 perf_remove_from_context(group_leader, 0);
9940 list_for_each_entry(sibling, &group_leader->sibling_list,
9942 perf_remove_from_context(sibling, 0);
9947 * Wait for everybody to stop referencing the events through
9948 * the old lists, before installing it on new lists.
9953 * Install the group siblings before the group leader.
9955 * Because a group leader will try and install the entire group
9956 * (through the sibling list, which is still in-tact), we can
9957 * end up with siblings installed in the wrong context.
9959 * By installing siblings first we NO-OP because they're not
9960 * reachable through the group lists.
9962 list_for_each_entry(sibling, &group_leader->sibling_list,
9964 perf_event__state_init(sibling);
9965 perf_install_in_context(ctx, sibling, sibling->cpu);
9970 * Removing from the context ends up with disabled
9971 * event. What we want here is event in the initial
9972 * startup state, ready to be add into new context.
9974 perf_event__state_init(group_leader);
9975 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9979 * Now that all events are installed in @ctx, nothing
9980 * references @gctx anymore, so drop the last reference we have
9987 * Precalculate sample_data sizes; do while holding ctx::mutex such
9988 * that we're serialized against further additions and before
9989 * perf_install_in_context() which is the point the event is active and
9990 * can use these values.
9992 perf_event__header_size(event);
9993 perf_event__id_header_size(event);
9995 event->owner = current;
9997 perf_install_in_context(ctx, event, event->cpu);
9998 perf_unpin_context(ctx);
10001 perf_event_ctx_unlock(group_leader, gctx);
10002 mutex_unlock(&ctx->mutex);
10005 mutex_unlock(&task->signal->cred_guard_mutex);
10006 put_task_struct(task);
10011 mutex_lock(¤t->perf_event_mutex);
10012 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10013 mutex_unlock(¤t->perf_event_mutex);
10016 * Drop the reference on the group_event after placing the
10017 * new event on the sibling_list. This ensures destruction
10018 * of the group leader will find the pointer to itself in
10019 * perf_group_detach().
10022 fd_install(event_fd, event_file);
10027 perf_event_ctx_unlock(group_leader, gctx);
10028 mutex_unlock(&ctx->mutex);
10032 perf_unpin_context(ctx);
10036 * If event_file is set, the fput() above will have called ->release()
10037 * and that will take care of freeing the event.
10043 mutex_unlock(&task->signal->cred_guard_mutex);
10048 put_task_struct(task);
10052 put_unused_fd(event_fd);
10057 * perf_event_create_kernel_counter
10059 * @attr: attributes of the counter to create
10060 * @cpu: cpu in which the counter is bound
10061 * @task: task to profile (NULL for percpu)
10063 struct perf_event *
10064 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10065 struct task_struct *task,
10066 perf_overflow_handler_t overflow_handler,
10069 struct perf_event_context *ctx;
10070 struct perf_event *event;
10074 * Get the target context (task or percpu):
10077 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10078 overflow_handler, context, -1);
10079 if (IS_ERR(event)) {
10080 err = PTR_ERR(event);
10084 /* Mark owner so we could distinguish it from user events. */
10085 event->owner = TASK_TOMBSTONE;
10087 ctx = find_get_context(event->pmu, task, event);
10089 err = PTR_ERR(ctx);
10093 WARN_ON_ONCE(ctx->parent_ctx);
10094 mutex_lock(&ctx->mutex);
10095 if (ctx->task == TASK_TOMBSTONE) {
10100 if (!exclusive_event_installable(event, ctx)) {
10105 perf_install_in_context(ctx, event, cpu);
10106 perf_unpin_context(ctx);
10107 mutex_unlock(&ctx->mutex);
10112 mutex_unlock(&ctx->mutex);
10113 perf_unpin_context(ctx);
10118 return ERR_PTR(err);
10120 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10122 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10124 struct perf_event_context *src_ctx;
10125 struct perf_event_context *dst_ctx;
10126 struct perf_event *event, *tmp;
10129 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10130 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10133 * See perf_event_ctx_lock() for comments on the details
10134 * of swizzling perf_event::ctx.
10136 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10137 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10139 perf_remove_from_context(event, 0);
10140 unaccount_event_cpu(event, src_cpu);
10142 list_add(&event->migrate_entry, &events);
10146 * Wait for the events to quiesce before re-instating them.
10151 * Re-instate events in 2 passes.
10153 * Skip over group leaders and only install siblings on this first
10154 * pass, siblings will not get enabled without a leader, however a
10155 * leader will enable its siblings, even if those are still on the old
10158 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10159 if (event->group_leader == event)
10162 list_del(&event->migrate_entry);
10163 if (event->state >= PERF_EVENT_STATE_OFF)
10164 event->state = PERF_EVENT_STATE_INACTIVE;
10165 account_event_cpu(event, dst_cpu);
10166 perf_install_in_context(dst_ctx, event, dst_cpu);
10171 * Once all the siblings are setup properly, install the group leaders
10174 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10175 list_del(&event->migrate_entry);
10176 if (event->state >= PERF_EVENT_STATE_OFF)
10177 event->state = PERF_EVENT_STATE_INACTIVE;
10178 account_event_cpu(event, dst_cpu);
10179 perf_install_in_context(dst_ctx, event, dst_cpu);
10182 mutex_unlock(&dst_ctx->mutex);
10183 mutex_unlock(&src_ctx->mutex);
10185 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10187 static void sync_child_event(struct perf_event *child_event,
10188 struct task_struct *child)
10190 struct perf_event *parent_event = child_event->parent;
10193 if (child_event->attr.inherit_stat)
10194 perf_event_read_event(child_event, child);
10196 child_val = perf_event_count(child_event);
10199 * Add back the child's count to the parent's count:
10201 atomic64_add(child_val, &parent_event->child_count);
10202 atomic64_add(child_event->total_time_enabled,
10203 &parent_event->child_total_time_enabled);
10204 atomic64_add(child_event->total_time_running,
10205 &parent_event->child_total_time_running);
10209 perf_event_exit_event(struct perf_event *child_event,
10210 struct perf_event_context *child_ctx,
10211 struct task_struct *child)
10213 struct perf_event *parent_event = child_event->parent;
10216 * Do not destroy the 'original' grouping; because of the context
10217 * switch optimization the original events could've ended up in a
10218 * random child task.
10220 * If we were to destroy the original group, all group related
10221 * operations would cease to function properly after this random
10224 * Do destroy all inherited groups, we don't care about those
10225 * and being thorough is better.
10227 raw_spin_lock_irq(&child_ctx->lock);
10228 WARN_ON_ONCE(child_ctx->is_active);
10231 perf_group_detach(child_event);
10232 list_del_event(child_event, child_ctx);
10233 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10234 raw_spin_unlock_irq(&child_ctx->lock);
10237 * Parent events are governed by their filedesc, retain them.
10239 if (!parent_event) {
10240 perf_event_wakeup(child_event);
10244 * Child events can be cleaned up.
10247 sync_child_event(child_event, child);
10250 * Remove this event from the parent's list
10252 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10253 mutex_lock(&parent_event->child_mutex);
10254 list_del_init(&child_event->child_list);
10255 mutex_unlock(&parent_event->child_mutex);
10258 * Kick perf_poll() for is_event_hup().
10260 perf_event_wakeup(parent_event);
10261 free_event(child_event);
10262 put_event(parent_event);
10265 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10267 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10268 struct perf_event *child_event, *next;
10270 WARN_ON_ONCE(child != current);
10272 child_ctx = perf_pin_task_context(child, ctxn);
10277 * In order to reduce the amount of tricky in ctx tear-down, we hold
10278 * ctx::mutex over the entire thing. This serializes against almost
10279 * everything that wants to access the ctx.
10281 * The exception is sys_perf_event_open() /
10282 * perf_event_create_kernel_count() which does find_get_context()
10283 * without ctx::mutex (it cannot because of the move_group double mutex
10284 * lock thing). See the comments in perf_install_in_context().
10286 mutex_lock(&child_ctx->mutex);
10289 * In a single ctx::lock section, de-schedule the events and detach the
10290 * context from the task such that we cannot ever get it scheduled back
10293 raw_spin_lock_irq(&child_ctx->lock);
10294 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10297 * Now that the context is inactive, destroy the task <-> ctx relation
10298 * and mark the context dead.
10300 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10301 put_ctx(child_ctx); /* cannot be last */
10302 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10303 put_task_struct(current); /* cannot be last */
10305 clone_ctx = unclone_ctx(child_ctx);
10306 raw_spin_unlock_irq(&child_ctx->lock);
10309 put_ctx(clone_ctx);
10312 * Report the task dead after unscheduling the events so that we
10313 * won't get any samples after PERF_RECORD_EXIT. We can however still
10314 * get a few PERF_RECORD_READ events.
10316 perf_event_task(child, child_ctx, 0);
10318 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10319 perf_event_exit_event(child_event, child_ctx, child);
10321 mutex_unlock(&child_ctx->mutex);
10323 put_ctx(child_ctx);
10327 * When a child task exits, feed back event values to parent events.
10329 * Can be called with cred_guard_mutex held when called from
10330 * install_exec_creds().
10332 void perf_event_exit_task(struct task_struct *child)
10334 struct perf_event *event, *tmp;
10337 mutex_lock(&child->perf_event_mutex);
10338 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10340 list_del_init(&event->owner_entry);
10343 * Ensure the list deletion is visible before we clear
10344 * the owner, closes a race against perf_release() where
10345 * we need to serialize on the owner->perf_event_mutex.
10347 smp_store_release(&event->owner, NULL);
10349 mutex_unlock(&child->perf_event_mutex);
10351 for_each_task_context_nr(ctxn)
10352 perf_event_exit_task_context(child, ctxn);
10355 * The perf_event_exit_task_context calls perf_event_task
10356 * with child's task_ctx, which generates EXIT events for
10357 * child contexts and sets child->perf_event_ctxp[] to NULL.
10358 * At this point we need to send EXIT events to cpu contexts.
10360 perf_event_task(child, NULL, 0);
10363 static void perf_free_event(struct perf_event *event,
10364 struct perf_event_context *ctx)
10366 struct perf_event *parent = event->parent;
10368 if (WARN_ON_ONCE(!parent))
10371 mutex_lock(&parent->child_mutex);
10372 list_del_init(&event->child_list);
10373 mutex_unlock(&parent->child_mutex);
10377 raw_spin_lock_irq(&ctx->lock);
10378 perf_group_detach(event);
10379 list_del_event(event, ctx);
10380 raw_spin_unlock_irq(&ctx->lock);
10385 * Free an unexposed, unused context as created by inheritance by
10386 * perf_event_init_task below, used by fork() in case of fail.
10388 * Not all locks are strictly required, but take them anyway to be nice and
10389 * help out with the lockdep assertions.
10391 void perf_event_free_task(struct task_struct *task)
10393 struct perf_event_context *ctx;
10394 struct perf_event *event, *tmp;
10397 for_each_task_context_nr(ctxn) {
10398 ctx = task->perf_event_ctxp[ctxn];
10402 mutex_lock(&ctx->mutex);
10404 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
10406 perf_free_event(event, ctx);
10408 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
10410 perf_free_event(event, ctx);
10412 if (!list_empty(&ctx->pinned_groups) ||
10413 !list_empty(&ctx->flexible_groups))
10416 mutex_unlock(&ctx->mutex);
10422 void perf_event_delayed_put(struct task_struct *task)
10426 for_each_task_context_nr(ctxn)
10427 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10430 struct file *perf_event_get(unsigned int fd)
10434 file = fget_raw(fd);
10436 return ERR_PTR(-EBADF);
10438 if (file->f_op != &perf_fops) {
10440 return ERR_PTR(-EBADF);
10446 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10449 return ERR_PTR(-EINVAL);
10451 return &event->attr;
10455 * inherit a event from parent task to child task:
10457 static struct perf_event *
10458 inherit_event(struct perf_event *parent_event,
10459 struct task_struct *parent,
10460 struct perf_event_context *parent_ctx,
10461 struct task_struct *child,
10462 struct perf_event *group_leader,
10463 struct perf_event_context *child_ctx)
10465 enum perf_event_active_state parent_state = parent_event->state;
10466 struct perf_event *child_event;
10467 unsigned long flags;
10470 * Instead of creating recursive hierarchies of events,
10471 * we link inherited events back to the original parent,
10472 * which has a filp for sure, which we use as the reference
10475 if (parent_event->parent)
10476 parent_event = parent_event->parent;
10478 child_event = perf_event_alloc(&parent_event->attr,
10481 group_leader, parent_event,
10483 if (IS_ERR(child_event))
10484 return child_event;
10487 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10488 * must be under the same lock in order to serialize against
10489 * perf_event_release_kernel(), such that either we must observe
10490 * is_orphaned_event() or they will observe us on the child_list.
10492 mutex_lock(&parent_event->child_mutex);
10493 if (is_orphaned_event(parent_event) ||
10494 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10495 mutex_unlock(&parent_event->child_mutex);
10496 free_event(child_event);
10500 get_ctx(child_ctx);
10503 * Make the child state follow the state of the parent event,
10504 * not its attr.disabled bit. We hold the parent's mutex,
10505 * so we won't race with perf_event_{en, dis}able_family.
10507 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10508 child_event->state = PERF_EVENT_STATE_INACTIVE;
10510 child_event->state = PERF_EVENT_STATE_OFF;
10512 if (parent_event->attr.freq) {
10513 u64 sample_period = parent_event->hw.sample_period;
10514 struct hw_perf_event *hwc = &child_event->hw;
10516 hwc->sample_period = sample_period;
10517 hwc->last_period = sample_period;
10519 local64_set(&hwc->period_left, sample_period);
10522 child_event->ctx = child_ctx;
10523 child_event->overflow_handler = parent_event->overflow_handler;
10524 child_event->overflow_handler_context
10525 = parent_event->overflow_handler_context;
10528 * Precalculate sample_data sizes
10530 perf_event__header_size(child_event);
10531 perf_event__id_header_size(child_event);
10534 * Link it up in the child's context:
10536 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10537 add_event_to_ctx(child_event, child_ctx);
10538 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10541 * Link this into the parent event's child list
10543 list_add_tail(&child_event->child_list, &parent_event->child_list);
10544 mutex_unlock(&parent_event->child_mutex);
10546 return child_event;
10549 static int inherit_group(struct perf_event *parent_event,
10550 struct task_struct *parent,
10551 struct perf_event_context *parent_ctx,
10552 struct task_struct *child,
10553 struct perf_event_context *child_ctx)
10555 struct perf_event *leader;
10556 struct perf_event *sub;
10557 struct perf_event *child_ctr;
10559 leader = inherit_event(parent_event, parent, parent_ctx,
10560 child, NULL, child_ctx);
10561 if (IS_ERR(leader))
10562 return PTR_ERR(leader);
10563 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10564 child_ctr = inherit_event(sub, parent, parent_ctx,
10565 child, leader, child_ctx);
10566 if (IS_ERR(child_ctr))
10567 return PTR_ERR(child_ctr);
10573 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10574 struct perf_event_context *parent_ctx,
10575 struct task_struct *child, int ctxn,
10576 int *inherited_all)
10579 struct perf_event_context *child_ctx;
10581 if (!event->attr.inherit) {
10582 *inherited_all = 0;
10586 child_ctx = child->perf_event_ctxp[ctxn];
10589 * This is executed from the parent task context, so
10590 * inherit events that have been marked for cloning.
10591 * First allocate and initialize a context for the
10595 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10599 child->perf_event_ctxp[ctxn] = child_ctx;
10602 ret = inherit_group(event, parent, parent_ctx,
10606 *inherited_all = 0;
10612 * Initialize the perf_event context in task_struct
10614 static int perf_event_init_context(struct task_struct *child, int ctxn)
10616 struct perf_event_context *child_ctx, *parent_ctx;
10617 struct perf_event_context *cloned_ctx;
10618 struct perf_event *event;
10619 struct task_struct *parent = current;
10620 int inherited_all = 1;
10621 unsigned long flags;
10624 if (likely(!parent->perf_event_ctxp[ctxn]))
10628 * If the parent's context is a clone, pin it so it won't get
10629 * swapped under us.
10631 parent_ctx = perf_pin_task_context(parent, ctxn);
10636 * No need to check if parent_ctx != NULL here; since we saw
10637 * it non-NULL earlier, the only reason for it to become NULL
10638 * is if we exit, and since we're currently in the middle of
10639 * a fork we can't be exiting at the same time.
10643 * Lock the parent list. No need to lock the child - not PID
10644 * hashed yet and not running, so nobody can access it.
10646 mutex_lock(&parent_ctx->mutex);
10649 * We dont have to disable NMIs - we are only looking at
10650 * the list, not manipulating it:
10652 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10653 ret = inherit_task_group(event, parent, parent_ctx,
10654 child, ctxn, &inherited_all);
10660 * We can't hold ctx->lock when iterating the ->flexible_group list due
10661 * to allocations, but we need to prevent rotation because
10662 * rotate_ctx() will change the list from interrupt context.
10664 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10665 parent_ctx->rotate_disable = 1;
10666 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10668 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10669 ret = inherit_task_group(event, parent, parent_ctx,
10670 child, ctxn, &inherited_all);
10675 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10676 parent_ctx->rotate_disable = 0;
10678 child_ctx = child->perf_event_ctxp[ctxn];
10680 if (child_ctx && inherited_all) {
10682 * Mark the child context as a clone of the parent
10683 * context, or of whatever the parent is a clone of.
10685 * Note that if the parent is a clone, the holding of
10686 * parent_ctx->lock avoids it from being uncloned.
10688 cloned_ctx = parent_ctx->parent_ctx;
10690 child_ctx->parent_ctx = cloned_ctx;
10691 child_ctx->parent_gen = parent_ctx->parent_gen;
10693 child_ctx->parent_ctx = parent_ctx;
10694 child_ctx->parent_gen = parent_ctx->generation;
10696 get_ctx(child_ctx->parent_ctx);
10699 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10700 mutex_unlock(&parent_ctx->mutex);
10702 perf_unpin_context(parent_ctx);
10703 put_ctx(parent_ctx);
10709 * Initialize the perf_event context in task_struct
10711 int perf_event_init_task(struct task_struct *child)
10715 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10716 mutex_init(&child->perf_event_mutex);
10717 INIT_LIST_HEAD(&child->perf_event_list);
10719 for_each_task_context_nr(ctxn) {
10720 ret = perf_event_init_context(child, ctxn);
10722 perf_event_free_task(child);
10730 static void __init perf_event_init_all_cpus(void)
10732 struct swevent_htable *swhash;
10735 for_each_possible_cpu(cpu) {
10736 swhash = &per_cpu(swevent_htable, cpu);
10737 mutex_init(&swhash->hlist_mutex);
10738 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10740 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10741 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10743 #ifdef CONFIG_CGROUP_PERF
10744 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10746 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10750 int perf_event_init_cpu(unsigned int cpu)
10752 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10754 mutex_lock(&swhash->hlist_mutex);
10755 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10756 struct swevent_hlist *hlist;
10758 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10760 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10762 mutex_unlock(&swhash->hlist_mutex);
10766 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10767 static void __perf_event_exit_context(void *__info)
10769 struct perf_event_context *ctx = __info;
10770 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10771 struct perf_event *event;
10773 raw_spin_lock(&ctx->lock);
10774 list_for_each_entry(event, &ctx->event_list, event_entry)
10775 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10776 raw_spin_unlock(&ctx->lock);
10779 static void perf_event_exit_cpu_context(int cpu)
10781 struct perf_event_context *ctx;
10785 idx = srcu_read_lock(&pmus_srcu);
10786 list_for_each_entry_rcu(pmu, &pmus, entry) {
10787 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10789 mutex_lock(&ctx->mutex);
10790 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10791 mutex_unlock(&ctx->mutex);
10793 srcu_read_unlock(&pmus_srcu, idx);
10797 static void perf_event_exit_cpu_context(int cpu) { }
10801 int perf_event_exit_cpu(unsigned int cpu)
10803 perf_event_exit_cpu_context(cpu);
10808 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10812 for_each_online_cpu(cpu)
10813 perf_event_exit_cpu(cpu);
10819 * Run the perf reboot notifier at the very last possible moment so that
10820 * the generic watchdog code runs as long as possible.
10822 static struct notifier_block perf_reboot_notifier = {
10823 .notifier_call = perf_reboot,
10824 .priority = INT_MIN,
10827 void __init perf_event_init(void)
10831 idr_init(&pmu_idr);
10833 perf_event_init_all_cpus();
10834 init_srcu_struct(&pmus_srcu);
10835 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10836 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10837 perf_pmu_register(&perf_task_clock, NULL, -1);
10838 perf_tp_register();
10839 perf_event_init_cpu(smp_processor_id());
10840 register_reboot_notifier(&perf_reboot_notifier);
10842 ret = init_hw_breakpoint();
10843 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10846 * Build time assertion that we keep the data_head at the intended
10847 * location. IOW, validation we got the __reserved[] size right.
10849 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10853 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10856 struct perf_pmu_events_attr *pmu_attr =
10857 container_of(attr, struct perf_pmu_events_attr, attr);
10859 if (pmu_attr->event_str)
10860 return sprintf(page, "%s\n", pmu_attr->event_str);
10864 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10866 static int __init perf_event_sysfs_init(void)
10871 mutex_lock(&pmus_lock);
10873 ret = bus_register(&pmu_bus);
10877 list_for_each_entry(pmu, &pmus, entry) {
10878 if (!pmu->name || pmu->type < 0)
10881 ret = pmu_dev_alloc(pmu);
10882 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10884 pmu_bus_running = 1;
10888 mutex_unlock(&pmus_lock);
10892 device_initcall(perf_event_sysfs_init);
10894 #ifdef CONFIG_CGROUP_PERF
10895 static struct cgroup_subsys_state *
10896 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10898 struct perf_cgroup *jc;
10900 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10902 return ERR_PTR(-ENOMEM);
10904 jc->info = alloc_percpu(struct perf_cgroup_info);
10907 return ERR_PTR(-ENOMEM);
10913 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10915 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10917 free_percpu(jc->info);
10921 static int __perf_cgroup_move(void *info)
10923 struct task_struct *task = info;
10925 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10930 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10932 struct task_struct *task;
10933 struct cgroup_subsys_state *css;
10935 cgroup_taskset_for_each(task, css, tset)
10936 task_function_call(task, __perf_cgroup_move, task);
10939 struct cgroup_subsys perf_event_cgrp_subsys = {
10940 .css_alloc = perf_cgroup_css_alloc,
10941 .css_free = perf_cgroup_css_free,
10942 .attach = perf_cgroup_attach,
10944 #endif /* CONFIG_CGROUP_PERF */