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 __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3543 u16 local_pkg, event_pkg;
3545 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3546 int local_cpu = smp_processor_id();
3548 event_pkg = topology_physical_package_id(event_cpu);
3549 local_pkg = topology_physical_package_id(local_cpu);
3551 if (event_pkg == local_pkg)
3559 * Cross CPU call to read the hardware event
3561 static void __perf_event_read(void *info)
3563 struct perf_read_data *data = info;
3564 struct perf_event *sub, *event = data->event;
3565 struct perf_event_context *ctx = event->ctx;
3566 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3567 struct pmu *pmu = event->pmu;
3570 * If this is a task context, we need to check whether it is
3571 * the current task context of this cpu. If not it has been
3572 * scheduled out before the smp call arrived. In that case
3573 * event->count would have been updated to a recent sample
3574 * when the event was scheduled out.
3576 if (ctx->task && cpuctx->task_ctx != ctx)
3579 raw_spin_lock(&ctx->lock);
3580 if (ctx->is_active) {
3581 update_context_time(ctx);
3582 update_cgrp_time_from_event(event);
3585 update_event_times(event);
3586 if (event->state != PERF_EVENT_STATE_ACTIVE)
3595 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3599 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3600 update_event_times(sub);
3601 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3603 * Use sibling's PMU rather than @event's since
3604 * sibling could be on different (eg: software) PMU.
3606 sub->pmu->read(sub);
3610 data->ret = pmu->commit_txn(pmu);
3613 raw_spin_unlock(&ctx->lock);
3616 static inline u64 perf_event_count(struct perf_event *event)
3618 if (event->pmu->count)
3619 return event->pmu->count(event);
3621 return __perf_event_count(event);
3625 * NMI-safe method to read a local event, that is an event that
3627 * - either for the current task, or for this CPU
3628 * - does not have inherit set, for inherited task events
3629 * will not be local and we cannot read them atomically
3630 * - must not have a pmu::count method
3632 u64 perf_event_read_local(struct perf_event *event)
3634 unsigned long flags;
3638 * Disabling interrupts avoids all counter scheduling (context
3639 * switches, timer based rotation and IPIs).
3641 local_irq_save(flags);
3643 /* If this is a per-task event, it must be for current */
3644 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3645 event->hw.target != current);
3647 /* If this is a per-CPU event, it must be for this CPU */
3648 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3649 event->cpu != smp_processor_id());
3652 * It must not be an event with inherit set, we cannot read
3653 * all child counters from atomic context.
3655 WARN_ON_ONCE(event->attr.inherit);
3658 * It must not have a pmu::count method, those are not
3661 WARN_ON_ONCE(event->pmu->count);
3664 * If the event is currently on this CPU, its either a per-task event,
3665 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3668 if (event->oncpu == smp_processor_id())
3669 event->pmu->read(event);
3671 val = local64_read(&event->count);
3672 local_irq_restore(flags);
3677 static int perf_event_read(struct perf_event *event, bool group)
3679 int event_cpu, ret = 0;
3682 * If event is enabled and currently active on a CPU, update the
3683 * value in the event structure:
3685 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3686 struct perf_read_data data = {
3692 event_cpu = READ_ONCE(event->oncpu);
3693 if ((unsigned)event_cpu >= nr_cpu_ids)
3697 event_cpu = __perf_event_read_cpu(event, event_cpu);
3700 * Purposely ignore the smp_call_function_single() return
3703 * If event_cpu isn't a valid CPU it means the event got
3704 * scheduled out and that will have updated the event count.
3706 * Therefore, either way, we'll have an up-to-date event count
3709 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3712 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3713 struct perf_event_context *ctx = event->ctx;
3714 unsigned long flags;
3716 raw_spin_lock_irqsave(&ctx->lock, flags);
3718 * may read while context is not active
3719 * (e.g., thread is blocked), in that case
3720 * we cannot update context time
3722 if (ctx->is_active) {
3723 update_context_time(ctx);
3724 update_cgrp_time_from_event(event);
3727 update_group_times(event);
3729 update_event_times(event);
3730 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3737 * Initialize the perf_event context in a task_struct:
3739 static void __perf_event_init_context(struct perf_event_context *ctx)
3741 raw_spin_lock_init(&ctx->lock);
3742 mutex_init(&ctx->mutex);
3743 INIT_LIST_HEAD(&ctx->active_ctx_list);
3744 INIT_LIST_HEAD(&ctx->pinned_groups);
3745 INIT_LIST_HEAD(&ctx->flexible_groups);
3746 INIT_LIST_HEAD(&ctx->event_list);
3747 atomic_set(&ctx->refcount, 1);
3750 static struct perf_event_context *
3751 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3753 struct perf_event_context *ctx;
3755 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3759 __perf_event_init_context(ctx);
3762 get_task_struct(task);
3769 static struct task_struct *
3770 find_lively_task_by_vpid(pid_t vpid)
3772 struct task_struct *task;
3778 task = find_task_by_vpid(vpid);
3780 get_task_struct(task);
3784 return ERR_PTR(-ESRCH);
3790 * Returns a matching context with refcount and pincount.
3792 static struct perf_event_context *
3793 find_get_context(struct pmu *pmu, struct task_struct *task,
3794 struct perf_event *event)
3796 struct perf_event_context *ctx, *clone_ctx = NULL;
3797 struct perf_cpu_context *cpuctx;
3798 void *task_ctx_data = NULL;
3799 unsigned long flags;
3801 int cpu = event->cpu;
3804 /* Must be root to operate on a CPU event: */
3805 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3806 return ERR_PTR(-EACCES);
3809 * We could be clever and allow to attach a event to an
3810 * offline CPU and activate it when the CPU comes up, but
3813 if (!cpu_online(cpu))
3814 return ERR_PTR(-ENODEV);
3816 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3825 ctxn = pmu->task_ctx_nr;
3829 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3830 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3831 if (!task_ctx_data) {
3838 ctx = perf_lock_task_context(task, ctxn, &flags);
3840 clone_ctx = unclone_ctx(ctx);
3843 if (task_ctx_data && !ctx->task_ctx_data) {
3844 ctx->task_ctx_data = task_ctx_data;
3845 task_ctx_data = NULL;
3847 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3852 ctx = alloc_perf_context(pmu, task);
3857 if (task_ctx_data) {
3858 ctx->task_ctx_data = task_ctx_data;
3859 task_ctx_data = NULL;
3863 mutex_lock(&task->perf_event_mutex);
3865 * If it has already passed perf_event_exit_task().
3866 * we must see PF_EXITING, it takes this mutex too.
3868 if (task->flags & PF_EXITING)
3870 else if (task->perf_event_ctxp[ctxn])
3875 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3877 mutex_unlock(&task->perf_event_mutex);
3879 if (unlikely(err)) {
3888 kfree(task_ctx_data);
3892 kfree(task_ctx_data);
3893 return ERR_PTR(err);
3896 static void perf_event_free_filter(struct perf_event *event);
3897 static void perf_event_free_bpf_prog(struct perf_event *event);
3899 static void free_event_rcu(struct rcu_head *head)
3901 struct perf_event *event;
3903 event = container_of(head, struct perf_event, rcu_head);
3905 put_pid_ns(event->ns);
3906 perf_event_free_filter(event);
3910 static void ring_buffer_attach(struct perf_event *event,
3911 struct ring_buffer *rb);
3913 static void detach_sb_event(struct perf_event *event)
3915 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3917 raw_spin_lock(&pel->lock);
3918 list_del_rcu(&event->sb_list);
3919 raw_spin_unlock(&pel->lock);
3922 static bool is_sb_event(struct perf_event *event)
3924 struct perf_event_attr *attr = &event->attr;
3929 if (event->attach_state & PERF_ATTACH_TASK)
3932 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3933 attr->comm || attr->comm_exec ||
3935 attr->context_switch)
3940 static void unaccount_pmu_sb_event(struct perf_event *event)
3942 if (is_sb_event(event))
3943 detach_sb_event(event);
3946 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3951 if (is_cgroup_event(event))
3952 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3955 #ifdef CONFIG_NO_HZ_FULL
3956 static DEFINE_SPINLOCK(nr_freq_lock);
3959 static void unaccount_freq_event_nohz(void)
3961 #ifdef CONFIG_NO_HZ_FULL
3962 spin_lock(&nr_freq_lock);
3963 if (atomic_dec_and_test(&nr_freq_events))
3964 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3965 spin_unlock(&nr_freq_lock);
3969 static void unaccount_freq_event(void)
3971 if (tick_nohz_full_enabled())
3972 unaccount_freq_event_nohz();
3974 atomic_dec(&nr_freq_events);
3977 static void unaccount_event(struct perf_event *event)
3984 if (event->attach_state & PERF_ATTACH_TASK)
3986 if (event->attr.mmap || event->attr.mmap_data)
3987 atomic_dec(&nr_mmap_events);
3988 if (event->attr.comm)
3989 atomic_dec(&nr_comm_events);
3990 if (event->attr.task)
3991 atomic_dec(&nr_task_events);
3992 if (event->attr.freq)
3993 unaccount_freq_event();
3994 if (event->attr.context_switch) {
3996 atomic_dec(&nr_switch_events);
3998 if (is_cgroup_event(event))
4000 if (has_branch_stack(event))
4004 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4005 schedule_delayed_work(&perf_sched_work, HZ);
4008 unaccount_event_cpu(event, event->cpu);
4010 unaccount_pmu_sb_event(event);
4013 static void perf_sched_delayed(struct work_struct *work)
4015 mutex_lock(&perf_sched_mutex);
4016 if (atomic_dec_and_test(&perf_sched_count))
4017 static_branch_disable(&perf_sched_events);
4018 mutex_unlock(&perf_sched_mutex);
4022 * The following implement mutual exclusion of events on "exclusive" pmus
4023 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4024 * at a time, so we disallow creating events that might conflict, namely:
4026 * 1) cpu-wide events in the presence of per-task events,
4027 * 2) per-task events in the presence of cpu-wide events,
4028 * 3) two matching events on the same context.
4030 * The former two cases are handled in the allocation path (perf_event_alloc(),
4031 * _free_event()), the latter -- before the first perf_install_in_context().
4033 static int exclusive_event_init(struct perf_event *event)
4035 struct pmu *pmu = event->pmu;
4037 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4041 * Prevent co-existence of per-task and cpu-wide events on the
4042 * same exclusive pmu.
4044 * Negative pmu::exclusive_cnt means there are cpu-wide
4045 * events on this "exclusive" pmu, positive means there are
4048 * Since this is called in perf_event_alloc() path, event::ctx
4049 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4050 * to mean "per-task event", because unlike other attach states it
4051 * never gets cleared.
4053 if (event->attach_state & PERF_ATTACH_TASK) {
4054 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4057 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4064 static void exclusive_event_destroy(struct perf_event *event)
4066 struct pmu *pmu = event->pmu;
4068 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4071 /* see comment in exclusive_event_init() */
4072 if (event->attach_state & PERF_ATTACH_TASK)
4073 atomic_dec(&pmu->exclusive_cnt);
4075 atomic_inc(&pmu->exclusive_cnt);
4078 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4080 if ((e1->pmu == e2->pmu) &&
4081 (e1->cpu == e2->cpu ||
4088 /* Called under the same ctx::mutex as perf_install_in_context() */
4089 static bool exclusive_event_installable(struct perf_event *event,
4090 struct perf_event_context *ctx)
4092 struct perf_event *iter_event;
4093 struct pmu *pmu = event->pmu;
4095 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4098 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4099 if (exclusive_event_match(iter_event, event))
4106 static void perf_addr_filters_splice(struct perf_event *event,
4107 struct list_head *head);
4109 static void _free_event(struct perf_event *event)
4111 irq_work_sync(&event->pending);
4113 unaccount_event(event);
4117 * Can happen when we close an event with re-directed output.
4119 * Since we have a 0 refcount, perf_mmap_close() will skip
4120 * over us; possibly making our ring_buffer_put() the last.
4122 mutex_lock(&event->mmap_mutex);
4123 ring_buffer_attach(event, NULL);
4124 mutex_unlock(&event->mmap_mutex);
4127 if (is_cgroup_event(event))
4128 perf_detach_cgroup(event);
4130 if (!event->parent) {
4131 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4132 put_callchain_buffers();
4135 perf_event_free_bpf_prog(event);
4136 perf_addr_filters_splice(event, NULL);
4137 kfree(event->addr_filters_offs);
4140 event->destroy(event);
4143 put_ctx(event->ctx);
4145 exclusive_event_destroy(event);
4146 module_put(event->pmu->module);
4148 call_rcu(&event->rcu_head, free_event_rcu);
4152 * Used to free events which have a known refcount of 1, such as in error paths
4153 * where the event isn't exposed yet and inherited events.
4155 static void free_event(struct perf_event *event)
4157 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4158 "unexpected event refcount: %ld; ptr=%p\n",
4159 atomic_long_read(&event->refcount), event)) {
4160 /* leak to avoid use-after-free */
4168 * Remove user event from the owner task.
4170 static void perf_remove_from_owner(struct perf_event *event)
4172 struct task_struct *owner;
4176 * Matches the smp_store_release() in perf_event_exit_task(). If we
4177 * observe !owner it means the list deletion is complete and we can
4178 * indeed free this event, otherwise we need to serialize on
4179 * owner->perf_event_mutex.
4181 owner = lockless_dereference(event->owner);
4184 * Since delayed_put_task_struct() also drops the last
4185 * task reference we can safely take a new reference
4186 * while holding the rcu_read_lock().
4188 get_task_struct(owner);
4194 * If we're here through perf_event_exit_task() we're already
4195 * holding ctx->mutex which would be an inversion wrt. the
4196 * normal lock order.
4198 * However we can safely take this lock because its the child
4201 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4204 * We have to re-check the event->owner field, if it is cleared
4205 * we raced with perf_event_exit_task(), acquiring the mutex
4206 * ensured they're done, and we can proceed with freeing the
4210 list_del_init(&event->owner_entry);
4211 smp_store_release(&event->owner, NULL);
4213 mutex_unlock(&owner->perf_event_mutex);
4214 put_task_struct(owner);
4218 static void put_event(struct perf_event *event)
4220 if (!atomic_long_dec_and_test(&event->refcount))
4227 * Kill an event dead; while event:refcount will preserve the event
4228 * object, it will not preserve its functionality. Once the last 'user'
4229 * gives up the object, we'll destroy the thing.
4231 int perf_event_release_kernel(struct perf_event *event)
4233 struct perf_event_context *ctx = event->ctx;
4234 struct perf_event *child, *tmp;
4237 * If we got here through err_file: fput(event_file); we will not have
4238 * attached to a context yet.
4241 WARN_ON_ONCE(event->attach_state &
4242 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4246 if (!is_kernel_event(event))
4247 perf_remove_from_owner(event);
4249 ctx = perf_event_ctx_lock(event);
4250 WARN_ON_ONCE(ctx->parent_ctx);
4251 perf_remove_from_context(event, DETACH_GROUP);
4253 raw_spin_lock_irq(&ctx->lock);
4255 * Mark this even as STATE_DEAD, there is no external reference to it
4258 * Anybody acquiring event->child_mutex after the below loop _must_
4259 * also see this, most importantly inherit_event() which will avoid
4260 * placing more children on the list.
4262 * Thus this guarantees that we will in fact observe and kill _ALL_
4265 event->state = PERF_EVENT_STATE_DEAD;
4266 raw_spin_unlock_irq(&ctx->lock);
4268 perf_event_ctx_unlock(event, ctx);
4271 mutex_lock(&event->child_mutex);
4272 list_for_each_entry(child, &event->child_list, child_list) {
4275 * Cannot change, child events are not migrated, see the
4276 * comment with perf_event_ctx_lock_nested().
4278 ctx = lockless_dereference(child->ctx);
4280 * Since child_mutex nests inside ctx::mutex, we must jump
4281 * through hoops. We start by grabbing a reference on the ctx.
4283 * Since the event cannot get freed while we hold the
4284 * child_mutex, the context must also exist and have a !0
4290 * Now that we have a ctx ref, we can drop child_mutex, and
4291 * acquire ctx::mutex without fear of it going away. Then we
4292 * can re-acquire child_mutex.
4294 mutex_unlock(&event->child_mutex);
4295 mutex_lock(&ctx->mutex);
4296 mutex_lock(&event->child_mutex);
4299 * Now that we hold ctx::mutex and child_mutex, revalidate our
4300 * state, if child is still the first entry, it didn't get freed
4301 * and we can continue doing so.
4303 tmp = list_first_entry_or_null(&event->child_list,
4304 struct perf_event, child_list);
4306 perf_remove_from_context(child, DETACH_GROUP);
4307 list_del(&child->child_list);
4310 * This matches the refcount bump in inherit_event();
4311 * this can't be the last reference.
4316 mutex_unlock(&event->child_mutex);
4317 mutex_unlock(&ctx->mutex);
4321 mutex_unlock(&event->child_mutex);
4324 put_event(event); /* Must be the 'last' reference */
4327 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4330 * Called when the last reference to the file is gone.
4332 static int perf_release(struct inode *inode, struct file *file)
4334 perf_event_release_kernel(file->private_data);
4338 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4340 struct perf_event *child;
4346 mutex_lock(&event->child_mutex);
4348 (void)perf_event_read(event, false);
4349 total += perf_event_count(event);
4351 *enabled += event->total_time_enabled +
4352 atomic64_read(&event->child_total_time_enabled);
4353 *running += event->total_time_running +
4354 atomic64_read(&event->child_total_time_running);
4356 list_for_each_entry(child, &event->child_list, child_list) {
4357 (void)perf_event_read(child, false);
4358 total += perf_event_count(child);
4359 *enabled += child->total_time_enabled;
4360 *running += child->total_time_running;
4362 mutex_unlock(&event->child_mutex);
4366 EXPORT_SYMBOL_GPL(perf_event_read_value);
4368 static int __perf_read_group_add(struct perf_event *leader,
4369 u64 read_format, u64 *values)
4371 struct perf_event *sub;
4372 int n = 1; /* skip @nr */
4375 ret = perf_event_read(leader, true);
4380 * Since we co-schedule groups, {enabled,running} times of siblings
4381 * will be identical to those of the leader, so we only publish one
4384 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4385 values[n++] += leader->total_time_enabled +
4386 atomic64_read(&leader->child_total_time_enabled);
4389 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4390 values[n++] += leader->total_time_running +
4391 atomic64_read(&leader->child_total_time_running);
4395 * Write {count,id} tuples for every sibling.
4397 values[n++] += perf_event_count(leader);
4398 if (read_format & PERF_FORMAT_ID)
4399 values[n++] = primary_event_id(leader);
4401 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4402 values[n++] += perf_event_count(sub);
4403 if (read_format & PERF_FORMAT_ID)
4404 values[n++] = primary_event_id(sub);
4410 static int perf_read_group(struct perf_event *event,
4411 u64 read_format, char __user *buf)
4413 struct perf_event *leader = event->group_leader, *child;
4414 struct perf_event_context *ctx = leader->ctx;
4418 lockdep_assert_held(&ctx->mutex);
4420 values = kzalloc(event->read_size, GFP_KERNEL);
4424 values[0] = 1 + leader->nr_siblings;
4427 * By locking the child_mutex of the leader we effectively
4428 * lock the child list of all siblings.. XXX explain how.
4430 mutex_lock(&leader->child_mutex);
4432 ret = __perf_read_group_add(leader, read_format, values);
4436 list_for_each_entry(child, &leader->child_list, child_list) {
4437 ret = __perf_read_group_add(child, read_format, values);
4442 mutex_unlock(&leader->child_mutex);
4444 ret = event->read_size;
4445 if (copy_to_user(buf, values, event->read_size))
4450 mutex_unlock(&leader->child_mutex);
4456 static int perf_read_one(struct perf_event *event,
4457 u64 read_format, char __user *buf)
4459 u64 enabled, running;
4463 values[n++] = perf_event_read_value(event, &enabled, &running);
4464 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4465 values[n++] = enabled;
4466 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4467 values[n++] = running;
4468 if (read_format & PERF_FORMAT_ID)
4469 values[n++] = primary_event_id(event);
4471 if (copy_to_user(buf, values, n * sizeof(u64)))
4474 return n * sizeof(u64);
4477 static bool is_event_hup(struct perf_event *event)
4481 if (event->state > PERF_EVENT_STATE_EXIT)
4484 mutex_lock(&event->child_mutex);
4485 no_children = list_empty(&event->child_list);
4486 mutex_unlock(&event->child_mutex);
4491 * Read the performance event - simple non blocking version for now
4494 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4496 u64 read_format = event->attr.read_format;
4500 * Return end-of-file for a read on a event that is in
4501 * error state (i.e. because it was pinned but it couldn't be
4502 * scheduled on to the CPU at some point).
4504 if (event->state == PERF_EVENT_STATE_ERROR)
4507 if (count < event->read_size)
4510 WARN_ON_ONCE(event->ctx->parent_ctx);
4511 if (read_format & PERF_FORMAT_GROUP)
4512 ret = perf_read_group(event, read_format, buf);
4514 ret = perf_read_one(event, read_format, buf);
4520 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4522 struct perf_event *event = file->private_data;
4523 struct perf_event_context *ctx;
4526 ctx = perf_event_ctx_lock(event);
4527 ret = __perf_read(event, buf, count);
4528 perf_event_ctx_unlock(event, ctx);
4533 static unsigned int perf_poll(struct file *file, poll_table *wait)
4535 struct perf_event *event = file->private_data;
4536 struct ring_buffer *rb;
4537 unsigned int events = POLLHUP;
4539 poll_wait(file, &event->waitq, wait);
4541 if (is_event_hup(event))
4545 * Pin the event->rb by taking event->mmap_mutex; otherwise
4546 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4548 mutex_lock(&event->mmap_mutex);
4551 events = atomic_xchg(&rb->poll, 0);
4552 mutex_unlock(&event->mmap_mutex);
4556 static void _perf_event_reset(struct perf_event *event)
4558 (void)perf_event_read(event, false);
4559 local64_set(&event->count, 0);
4560 perf_event_update_userpage(event);
4564 * Holding the top-level event's child_mutex means that any
4565 * descendant process that has inherited this event will block
4566 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4567 * task existence requirements of perf_event_enable/disable.
4569 static void perf_event_for_each_child(struct perf_event *event,
4570 void (*func)(struct perf_event *))
4572 struct perf_event *child;
4574 WARN_ON_ONCE(event->ctx->parent_ctx);
4576 mutex_lock(&event->child_mutex);
4578 list_for_each_entry(child, &event->child_list, child_list)
4580 mutex_unlock(&event->child_mutex);
4583 static void perf_event_for_each(struct perf_event *event,
4584 void (*func)(struct perf_event *))
4586 struct perf_event_context *ctx = event->ctx;
4587 struct perf_event *sibling;
4589 lockdep_assert_held(&ctx->mutex);
4591 event = event->group_leader;
4593 perf_event_for_each_child(event, func);
4594 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4595 perf_event_for_each_child(sibling, func);
4598 static void __perf_event_period(struct perf_event *event,
4599 struct perf_cpu_context *cpuctx,
4600 struct perf_event_context *ctx,
4603 u64 value = *((u64 *)info);
4606 if (event->attr.freq) {
4607 event->attr.sample_freq = value;
4609 event->attr.sample_period = value;
4610 event->hw.sample_period = value;
4613 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4615 perf_pmu_disable(ctx->pmu);
4617 * We could be throttled; unthrottle now to avoid the tick
4618 * trying to unthrottle while we already re-started the event.
4620 if (event->hw.interrupts == MAX_INTERRUPTS) {
4621 event->hw.interrupts = 0;
4622 perf_log_throttle(event, 1);
4624 event->pmu->stop(event, PERF_EF_UPDATE);
4627 local64_set(&event->hw.period_left, 0);
4630 event->pmu->start(event, PERF_EF_RELOAD);
4631 perf_pmu_enable(ctx->pmu);
4635 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4639 if (!is_sampling_event(event))
4642 if (copy_from_user(&value, arg, sizeof(value)))
4648 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4651 event_function_call(event, __perf_event_period, &value);
4656 static const struct file_operations perf_fops;
4658 static inline int perf_fget_light(int fd, struct fd *p)
4660 struct fd f = fdget(fd);
4664 if (f.file->f_op != &perf_fops) {
4672 static int perf_event_set_output(struct perf_event *event,
4673 struct perf_event *output_event);
4674 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4675 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4677 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4679 void (*func)(struct perf_event *);
4683 case PERF_EVENT_IOC_ENABLE:
4684 func = _perf_event_enable;
4686 case PERF_EVENT_IOC_DISABLE:
4687 func = _perf_event_disable;
4689 case PERF_EVENT_IOC_RESET:
4690 func = _perf_event_reset;
4693 case PERF_EVENT_IOC_REFRESH:
4694 return _perf_event_refresh(event, arg);
4696 case PERF_EVENT_IOC_PERIOD:
4697 return perf_event_period(event, (u64 __user *)arg);
4699 case PERF_EVENT_IOC_ID:
4701 u64 id = primary_event_id(event);
4703 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4708 case PERF_EVENT_IOC_SET_OUTPUT:
4712 struct perf_event *output_event;
4714 ret = perf_fget_light(arg, &output);
4717 output_event = output.file->private_data;
4718 ret = perf_event_set_output(event, output_event);
4721 ret = perf_event_set_output(event, NULL);
4726 case PERF_EVENT_IOC_SET_FILTER:
4727 return perf_event_set_filter(event, (void __user *)arg);
4729 case PERF_EVENT_IOC_SET_BPF:
4730 return perf_event_set_bpf_prog(event, arg);
4732 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4733 struct ring_buffer *rb;
4736 rb = rcu_dereference(event->rb);
4737 if (!rb || !rb->nr_pages) {
4741 rb_toggle_paused(rb, !!arg);
4749 if (flags & PERF_IOC_FLAG_GROUP)
4750 perf_event_for_each(event, func);
4752 perf_event_for_each_child(event, func);
4757 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4759 struct perf_event *event = file->private_data;
4760 struct perf_event_context *ctx;
4763 ctx = perf_event_ctx_lock(event);
4764 ret = _perf_ioctl(event, cmd, arg);
4765 perf_event_ctx_unlock(event, ctx);
4770 #ifdef CONFIG_COMPAT
4771 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4774 switch (_IOC_NR(cmd)) {
4775 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4776 case _IOC_NR(PERF_EVENT_IOC_ID):
4777 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4778 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4779 cmd &= ~IOCSIZE_MASK;
4780 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4784 return perf_ioctl(file, cmd, arg);
4787 # define perf_compat_ioctl NULL
4790 int perf_event_task_enable(void)
4792 struct perf_event_context *ctx;
4793 struct perf_event *event;
4795 mutex_lock(¤t->perf_event_mutex);
4796 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4797 ctx = perf_event_ctx_lock(event);
4798 perf_event_for_each_child(event, _perf_event_enable);
4799 perf_event_ctx_unlock(event, ctx);
4801 mutex_unlock(¤t->perf_event_mutex);
4806 int perf_event_task_disable(void)
4808 struct perf_event_context *ctx;
4809 struct perf_event *event;
4811 mutex_lock(¤t->perf_event_mutex);
4812 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4813 ctx = perf_event_ctx_lock(event);
4814 perf_event_for_each_child(event, _perf_event_disable);
4815 perf_event_ctx_unlock(event, ctx);
4817 mutex_unlock(¤t->perf_event_mutex);
4822 static int perf_event_index(struct perf_event *event)
4824 if (event->hw.state & PERF_HES_STOPPED)
4827 if (event->state != PERF_EVENT_STATE_ACTIVE)
4830 return event->pmu->event_idx(event);
4833 static void calc_timer_values(struct perf_event *event,
4840 *now = perf_clock();
4841 ctx_time = event->shadow_ctx_time + *now;
4842 *enabled = ctx_time - event->tstamp_enabled;
4843 *running = ctx_time - event->tstamp_running;
4846 static void perf_event_init_userpage(struct perf_event *event)
4848 struct perf_event_mmap_page *userpg;
4849 struct ring_buffer *rb;
4852 rb = rcu_dereference(event->rb);
4856 userpg = rb->user_page;
4858 /* Allow new userspace to detect that bit 0 is deprecated */
4859 userpg->cap_bit0_is_deprecated = 1;
4860 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4861 userpg->data_offset = PAGE_SIZE;
4862 userpg->data_size = perf_data_size(rb);
4868 void __weak arch_perf_update_userpage(
4869 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4874 * Callers need to ensure there can be no nesting of this function, otherwise
4875 * the seqlock logic goes bad. We can not serialize this because the arch
4876 * code calls this from NMI context.
4878 void perf_event_update_userpage(struct perf_event *event)
4880 struct perf_event_mmap_page *userpg;
4881 struct ring_buffer *rb;
4882 u64 enabled, running, now;
4885 rb = rcu_dereference(event->rb);
4890 * compute total_time_enabled, total_time_running
4891 * based on snapshot values taken when the event
4892 * was last scheduled in.
4894 * we cannot simply called update_context_time()
4895 * because of locking issue as we can be called in
4898 calc_timer_values(event, &now, &enabled, &running);
4900 userpg = rb->user_page;
4902 * Disable preemption so as to not let the corresponding user-space
4903 * spin too long if we get preempted.
4908 userpg->index = perf_event_index(event);
4909 userpg->offset = perf_event_count(event);
4911 userpg->offset -= local64_read(&event->hw.prev_count);
4913 userpg->time_enabled = enabled +
4914 atomic64_read(&event->child_total_time_enabled);
4916 userpg->time_running = running +
4917 atomic64_read(&event->child_total_time_running);
4919 arch_perf_update_userpage(event, userpg, now);
4928 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4930 struct perf_event *event = vma->vm_file->private_data;
4931 struct ring_buffer *rb;
4932 int ret = VM_FAULT_SIGBUS;
4934 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4935 if (vmf->pgoff == 0)
4941 rb = rcu_dereference(event->rb);
4945 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4948 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4952 get_page(vmf->page);
4953 vmf->page->mapping = vma->vm_file->f_mapping;
4954 vmf->page->index = vmf->pgoff;
4963 static void ring_buffer_attach(struct perf_event *event,
4964 struct ring_buffer *rb)
4966 struct ring_buffer *old_rb = NULL;
4967 unsigned long flags;
4971 * Should be impossible, we set this when removing
4972 * event->rb_entry and wait/clear when adding event->rb_entry.
4974 WARN_ON_ONCE(event->rcu_pending);
4977 spin_lock_irqsave(&old_rb->event_lock, flags);
4978 list_del_rcu(&event->rb_entry);
4979 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4981 event->rcu_batches = get_state_synchronize_rcu();
4982 event->rcu_pending = 1;
4986 if (event->rcu_pending) {
4987 cond_synchronize_rcu(event->rcu_batches);
4988 event->rcu_pending = 0;
4991 spin_lock_irqsave(&rb->event_lock, flags);
4992 list_add_rcu(&event->rb_entry, &rb->event_list);
4993 spin_unlock_irqrestore(&rb->event_lock, flags);
4997 * Avoid racing with perf_mmap_close(AUX): stop the event
4998 * before swizzling the event::rb pointer; if it's getting
4999 * unmapped, its aux_mmap_count will be 0 and it won't
5000 * restart. See the comment in __perf_pmu_output_stop().
5002 * Data will inevitably be lost when set_output is done in
5003 * mid-air, but then again, whoever does it like this is
5004 * not in for the data anyway.
5007 perf_event_stop(event, 0);
5009 rcu_assign_pointer(event->rb, rb);
5012 ring_buffer_put(old_rb);
5014 * Since we detached before setting the new rb, so that we
5015 * could attach the new rb, we could have missed a wakeup.
5018 wake_up_all(&event->waitq);
5022 static void ring_buffer_wakeup(struct perf_event *event)
5024 struct ring_buffer *rb;
5027 rb = rcu_dereference(event->rb);
5029 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5030 wake_up_all(&event->waitq);
5035 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5037 struct ring_buffer *rb;
5040 rb = rcu_dereference(event->rb);
5042 if (!atomic_inc_not_zero(&rb->refcount))
5050 void ring_buffer_put(struct ring_buffer *rb)
5052 if (!atomic_dec_and_test(&rb->refcount))
5055 WARN_ON_ONCE(!list_empty(&rb->event_list));
5057 call_rcu(&rb->rcu_head, rb_free_rcu);
5060 static void perf_mmap_open(struct vm_area_struct *vma)
5062 struct perf_event *event = vma->vm_file->private_data;
5064 atomic_inc(&event->mmap_count);
5065 atomic_inc(&event->rb->mmap_count);
5068 atomic_inc(&event->rb->aux_mmap_count);
5070 if (event->pmu->event_mapped)
5071 event->pmu->event_mapped(event);
5074 static void perf_pmu_output_stop(struct perf_event *event);
5077 * A buffer can be mmap()ed multiple times; either directly through the same
5078 * event, or through other events by use of perf_event_set_output().
5080 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5081 * the buffer here, where we still have a VM context. This means we need
5082 * to detach all events redirecting to us.
5084 static void perf_mmap_close(struct vm_area_struct *vma)
5086 struct perf_event *event = vma->vm_file->private_data;
5088 struct ring_buffer *rb = ring_buffer_get(event);
5089 struct user_struct *mmap_user = rb->mmap_user;
5090 int mmap_locked = rb->mmap_locked;
5091 unsigned long size = perf_data_size(rb);
5093 if (event->pmu->event_unmapped)
5094 event->pmu->event_unmapped(event);
5097 * rb->aux_mmap_count will always drop before rb->mmap_count and
5098 * event->mmap_count, so it is ok to use event->mmap_mutex to
5099 * serialize with perf_mmap here.
5101 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5102 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5104 * Stop all AUX events that are writing to this buffer,
5105 * so that we can free its AUX pages and corresponding PMU
5106 * data. Note that after rb::aux_mmap_count dropped to zero,
5107 * they won't start any more (see perf_aux_output_begin()).
5109 perf_pmu_output_stop(event);
5111 /* now it's safe to free the pages */
5112 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5113 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5115 /* this has to be the last one */
5117 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5119 mutex_unlock(&event->mmap_mutex);
5122 atomic_dec(&rb->mmap_count);
5124 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5127 ring_buffer_attach(event, NULL);
5128 mutex_unlock(&event->mmap_mutex);
5130 /* If there's still other mmap()s of this buffer, we're done. */
5131 if (atomic_read(&rb->mmap_count))
5135 * No other mmap()s, detach from all other events that might redirect
5136 * into the now unreachable buffer. Somewhat complicated by the
5137 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5141 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5142 if (!atomic_long_inc_not_zero(&event->refcount)) {
5144 * This event is en-route to free_event() which will
5145 * detach it and remove it from the list.
5151 mutex_lock(&event->mmap_mutex);
5153 * Check we didn't race with perf_event_set_output() which can
5154 * swizzle the rb from under us while we were waiting to
5155 * acquire mmap_mutex.
5157 * If we find a different rb; ignore this event, a next
5158 * iteration will no longer find it on the list. We have to
5159 * still restart the iteration to make sure we're not now
5160 * iterating the wrong list.
5162 if (event->rb == rb)
5163 ring_buffer_attach(event, NULL);
5165 mutex_unlock(&event->mmap_mutex);
5169 * Restart the iteration; either we're on the wrong list or
5170 * destroyed its integrity by doing a deletion.
5177 * It could be there's still a few 0-ref events on the list; they'll
5178 * get cleaned up by free_event() -- they'll also still have their
5179 * ref on the rb and will free it whenever they are done with it.
5181 * Aside from that, this buffer is 'fully' detached and unmapped,
5182 * undo the VM accounting.
5185 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5186 vma->vm_mm->pinned_vm -= mmap_locked;
5187 free_uid(mmap_user);
5190 ring_buffer_put(rb); /* could be last */
5193 static const struct vm_operations_struct perf_mmap_vmops = {
5194 .open = perf_mmap_open,
5195 .close = perf_mmap_close, /* non mergable */
5196 .fault = perf_mmap_fault,
5197 .page_mkwrite = perf_mmap_fault,
5200 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5202 struct perf_event *event = file->private_data;
5203 unsigned long user_locked, user_lock_limit;
5204 struct user_struct *user = current_user();
5205 unsigned long locked, lock_limit;
5206 struct ring_buffer *rb = NULL;
5207 unsigned long vma_size;
5208 unsigned long nr_pages;
5209 long user_extra = 0, extra = 0;
5210 int ret = 0, flags = 0;
5213 * Don't allow mmap() of inherited per-task counters. This would
5214 * create a performance issue due to all children writing to the
5217 if (event->cpu == -1 && event->attr.inherit)
5220 if (!(vma->vm_flags & VM_SHARED))
5223 vma_size = vma->vm_end - vma->vm_start;
5225 if (vma->vm_pgoff == 0) {
5226 nr_pages = (vma_size / PAGE_SIZE) - 1;
5229 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5230 * mapped, all subsequent mappings should have the same size
5231 * and offset. Must be above the normal perf buffer.
5233 u64 aux_offset, aux_size;
5238 nr_pages = vma_size / PAGE_SIZE;
5240 mutex_lock(&event->mmap_mutex);
5247 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5248 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5250 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5253 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5256 /* already mapped with a different offset */
5257 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5260 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5263 /* already mapped with a different size */
5264 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5267 if (!is_power_of_2(nr_pages))
5270 if (!atomic_inc_not_zero(&rb->mmap_count))
5273 if (rb_has_aux(rb)) {
5274 atomic_inc(&rb->aux_mmap_count);
5279 atomic_set(&rb->aux_mmap_count, 1);
5280 user_extra = nr_pages;
5286 * If we have rb pages ensure they're a power-of-two number, so we
5287 * can do bitmasks instead of modulo.
5289 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5292 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5295 WARN_ON_ONCE(event->ctx->parent_ctx);
5297 mutex_lock(&event->mmap_mutex);
5299 if (event->rb->nr_pages != nr_pages) {
5304 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5306 * Raced against perf_mmap_close() through
5307 * perf_event_set_output(). Try again, hope for better
5310 mutex_unlock(&event->mmap_mutex);
5317 user_extra = nr_pages + 1;
5320 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5323 * Increase the limit linearly with more CPUs:
5325 user_lock_limit *= num_online_cpus();
5327 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5329 if (user_locked > user_lock_limit)
5330 extra = user_locked - user_lock_limit;
5332 lock_limit = rlimit(RLIMIT_MEMLOCK);
5333 lock_limit >>= PAGE_SHIFT;
5334 locked = vma->vm_mm->pinned_vm + extra;
5336 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5337 !capable(CAP_IPC_LOCK)) {
5342 WARN_ON(!rb && event->rb);
5344 if (vma->vm_flags & VM_WRITE)
5345 flags |= RING_BUFFER_WRITABLE;
5348 rb = rb_alloc(nr_pages,
5349 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5357 atomic_set(&rb->mmap_count, 1);
5358 rb->mmap_user = get_current_user();
5359 rb->mmap_locked = extra;
5361 ring_buffer_attach(event, rb);
5363 perf_event_init_userpage(event);
5364 perf_event_update_userpage(event);
5366 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5367 event->attr.aux_watermark, flags);
5369 rb->aux_mmap_locked = extra;
5374 atomic_long_add(user_extra, &user->locked_vm);
5375 vma->vm_mm->pinned_vm += extra;
5377 atomic_inc(&event->mmap_count);
5379 atomic_dec(&rb->mmap_count);
5382 mutex_unlock(&event->mmap_mutex);
5385 * Since pinned accounting is per vm we cannot allow fork() to copy our
5388 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5389 vma->vm_ops = &perf_mmap_vmops;
5391 if (event->pmu->event_mapped)
5392 event->pmu->event_mapped(event);
5397 static int perf_fasync(int fd, struct file *filp, int on)
5399 struct inode *inode = file_inode(filp);
5400 struct perf_event *event = filp->private_data;
5404 retval = fasync_helper(fd, filp, on, &event->fasync);
5405 inode_unlock(inode);
5413 static const struct file_operations perf_fops = {
5414 .llseek = no_llseek,
5415 .release = perf_release,
5418 .unlocked_ioctl = perf_ioctl,
5419 .compat_ioctl = perf_compat_ioctl,
5421 .fasync = perf_fasync,
5427 * If there's data, ensure we set the poll() state and publish everything
5428 * to user-space before waking everybody up.
5431 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5433 /* only the parent has fasync state */
5435 event = event->parent;
5436 return &event->fasync;
5439 void perf_event_wakeup(struct perf_event *event)
5441 ring_buffer_wakeup(event);
5443 if (event->pending_kill) {
5444 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5445 event->pending_kill = 0;
5449 static void perf_pending_event(struct irq_work *entry)
5451 struct perf_event *event = container_of(entry,
5452 struct perf_event, pending);
5455 rctx = perf_swevent_get_recursion_context();
5457 * If we 'fail' here, that's OK, it means recursion is already disabled
5458 * and we won't recurse 'further'.
5461 if (event->pending_disable) {
5462 event->pending_disable = 0;
5463 perf_event_disable_local(event);
5466 if (event->pending_wakeup) {
5467 event->pending_wakeup = 0;
5468 perf_event_wakeup(event);
5472 perf_swevent_put_recursion_context(rctx);
5476 * We assume there is only KVM supporting the callbacks.
5477 * Later on, we might change it to a list if there is
5478 * another virtualization implementation supporting the callbacks.
5480 struct perf_guest_info_callbacks *perf_guest_cbs;
5482 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5484 perf_guest_cbs = cbs;
5487 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5489 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5491 perf_guest_cbs = NULL;
5494 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5497 perf_output_sample_regs(struct perf_output_handle *handle,
5498 struct pt_regs *regs, u64 mask)
5501 DECLARE_BITMAP(_mask, 64);
5503 bitmap_from_u64(_mask, mask);
5504 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5507 val = perf_reg_value(regs, bit);
5508 perf_output_put(handle, val);
5512 static void perf_sample_regs_user(struct perf_regs *regs_user,
5513 struct pt_regs *regs,
5514 struct pt_regs *regs_user_copy)
5516 if (user_mode(regs)) {
5517 regs_user->abi = perf_reg_abi(current);
5518 regs_user->regs = regs;
5519 } else if (current->mm) {
5520 perf_get_regs_user(regs_user, regs, regs_user_copy);
5522 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5523 regs_user->regs = NULL;
5527 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5528 struct pt_regs *regs)
5530 regs_intr->regs = regs;
5531 regs_intr->abi = perf_reg_abi(current);
5536 * Get remaining task size from user stack pointer.
5538 * It'd be better to take stack vma map and limit this more
5539 * precisly, but there's no way to get it safely under interrupt,
5540 * so using TASK_SIZE as limit.
5542 static u64 perf_ustack_task_size(struct pt_regs *regs)
5544 unsigned long addr = perf_user_stack_pointer(regs);
5546 if (!addr || addr >= TASK_SIZE)
5549 return TASK_SIZE - addr;
5553 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5554 struct pt_regs *regs)
5558 /* No regs, no stack pointer, no dump. */
5563 * Check if we fit in with the requested stack size into the:
5565 * If we don't, we limit the size to the TASK_SIZE.
5567 * - remaining sample size
5568 * If we don't, we customize the stack size to
5569 * fit in to the remaining sample size.
5572 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5573 stack_size = min(stack_size, (u16) task_size);
5575 /* Current header size plus static size and dynamic size. */
5576 header_size += 2 * sizeof(u64);
5578 /* Do we fit in with the current stack dump size? */
5579 if ((u16) (header_size + stack_size) < header_size) {
5581 * If we overflow the maximum size for the sample,
5582 * we customize the stack dump size to fit in.
5584 stack_size = USHRT_MAX - header_size - sizeof(u64);
5585 stack_size = round_up(stack_size, sizeof(u64));
5592 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5593 struct pt_regs *regs)
5595 /* Case of a kernel thread, nothing to dump */
5598 perf_output_put(handle, size);
5607 * - the size requested by user or the best one we can fit
5608 * in to the sample max size
5610 * - user stack dump data
5612 * - the actual dumped size
5616 perf_output_put(handle, dump_size);
5619 sp = perf_user_stack_pointer(regs);
5620 rem = __output_copy_user(handle, (void *) sp, dump_size);
5621 dyn_size = dump_size - rem;
5623 perf_output_skip(handle, rem);
5626 perf_output_put(handle, dyn_size);
5630 static void __perf_event_header__init_id(struct perf_event_header *header,
5631 struct perf_sample_data *data,
5632 struct perf_event *event)
5634 u64 sample_type = event->attr.sample_type;
5636 data->type = sample_type;
5637 header->size += event->id_header_size;
5639 if (sample_type & PERF_SAMPLE_TID) {
5640 /* namespace issues */
5641 data->tid_entry.pid = perf_event_pid(event, current);
5642 data->tid_entry.tid = perf_event_tid(event, current);
5645 if (sample_type & PERF_SAMPLE_TIME)
5646 data->time = perf_event_clock(event);
5648 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5649 data->id = primary_event_id(event);
5651 if (sample_type & PERF_SAMPLE_STREAM_ID)
5652 data->stream_id = event->id;
5654 if (sample_type & PERF_SAMPLE_CPU) {
5655 data->cpu_entry.cpu = raw_smp_processor_id();
5656 data->cpu_entry.reserved = 0;
5660 void perf_event_header__init_id(struct perf_event_header *header,
5661 struct perf_sample_data *data,
5662 struct perf_event *event)
5664 if (event->attr.sample_id_all)
5665 __perf_event_header__init_id(header, data, event);
5668 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5669 struct perf_sample_data *data)
5671 u64 sample_type = data->type;
5673 if (sample_type & PERF_SAMPLE_TID)
5674 perf_output_put(handle, data->tid_entry);
5676 if (sample_type & PERF_SAMPLE_TIME)
5677 perf_output_put(handle, data->time);
5679 if (sample_type & PERF_SAMPLE_ID)
5680 perf_output_put(handle, data->id);
5682 if (sample_type & PERF_SAMPLE_STREAM_ID)
5683 perf_output_put(handle, data->stream_id);
5685 if (sample_type & PERF_SAMPLE_CPU)
5686 perf_output_put(handle, data->cpu_entry);
5688 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5689 perf_output_put(handle, data->id);
5692 void perf_event__output_id_sample(struct perf_event *event,
5693 struct perf_output_handle *handle,
5694 struct perf_sample_data *sample)
5696 if (event->attr.sample_id_all)
5697 __perf_event__output_id_sample(handle, sample);
5700 static void perf_output_read_one(struct perf_output_handle *handle,
5701 struct perf_event *event,
5702 u64 enabled, u64 running)
5704 u64 read_format = event->attr.read_format;
5708 values[n++] = perf_event_count(event);
5709 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5710 values[n++] = enabled +
5711 atomic64_read(&event->child_total_time_enabled);
5713 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5714 values[n++] = running +
5715 atomic64_read(&event->child_total_time_running);
5717 if (read_format & PERF_FORMAT_ID)
5718 values[n++] = primary_event_id(event);
5720 __output_copy(handle, values, n * sizeof(u64));
5724 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5726 static void perf_output_read_group(struct perf_output_handle *handle,
5727 struct perf_event *event,
5728 u64 enabled, u64 running)
5730 struct perf_event *leader = event->group_leader, *sub;
5731 u64 read_format = event->attr.read_format;
5735 values[n++] = 1 + leader->nr_siblings;
5737 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5738 values[n++] = enabled;
5740 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5741 values[n++] = running;
5743 if (leader != event)
5744 leader->pmu->read(leader);
5746 values[n++] = perf_event_count(leader);
5747 if (read_format & PERF_FORMAT_ID)
5748 values[n++] = primary_event_id(leader);
5750 __output_copy(handle, values, n * sizeof(u64));
5752 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5755 if ((sub != event) &&
5756 (sub->state == PERF_EVENT_STATE_ACTIVE))
5757 sub->pmu->read(sub);
5759 values[n++] = perf_event_count(sub);
5760 if (read_format & PERF_FORMAT_ID)
5761 values[n++] = primary_event_id(sub);
5763 __output_copy(handle, values, n * sizeof(u64));
5767 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5768 PERF_FORMAT_TOTAL_TIME_RUNNING)
5770 static void perf_output_read(struct perf_output_handle *handle,
5771 struct perf_event *event)
5773 u64 enabled = 0, running = 0, now;
5774 u64 read_format = event->attr.read_format;
5777 * compute total_time_enabled, total_time_running
5778 * based on snapshot values taken when the event
5779 * was last scheduled in.
5781 * we cannot simply called update_context_time()
5782 * because of locking issue as we are called in
5785 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5786 calc_timer_values(event, &now, &enabled, &running);
5788 if (event->attr.read_format & PERF_FORMAT_GROUP)
5789 perf_output_read_group(handle, event, enabled, running);
5791 perf_output_read_one(handle, event, enabled, running);
5794 void perf_output_sample(struct perf_output_handle *handle,
5795 struct perf_event_header *header,
5796 struct perf_sample_data *data,
5797 struct perf_event *event)
5799 u64 sample_type = data->type;
5801 perf_output_put(handle, *header);
5803 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5804 perf_output_put(handle, data->id);
5806 if (sample_type & PERF_SAMPLE_IP)
5807 perf_output_put(handle, data->ip);
5809 if (sample_type & PERF_SAMPLE_TID)
5810 perf_output_put(handle, data->tid_entry);
5812 if (sample_type & PERF_SAMPLE_TIME)
5813 perf_output_put(handle, data->time);
5815 if (sample_type & PERF_SAMPLE_ADDR)
5816 perf_output_put(handle, data->addr);
5818 if (sample_type & PERF_SAMPLE_ID)
5819 perf_output_put(handle, data->id);
5821 if (sample_type & PERF_SAMPLE_STREAM_ID)
5822 perf_output_put(handle, data->stream_id);
5824 if (sample_type & PERF_SAMPLE_CPU)
5825 perf_output_put(handle, data->cpu_entry);
5827 if (sample_type & PERF_SAMPLE_PERIOD)
5828 perf_output_put(handle, data->period);
5830 if (sample_type & PERF_SAMPLE_READ)
5831 perf_output_read(handle, event);
5833 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5834 if (data->callchain) {
5837 if (data->callchain)
5838 size += data->callchain->nr;
5840 size *= sizeof(u64);
5842 __output_copy(handle, data->callchain, size);
5845 perf_output_put(handle, nr);
5849 if (sample_type & PERF_SAMPLE_RAW) {
5850 struct perf_raw_record *raw = data->raw;
5853 struct perf_raw_frag *frag = &raw->frag;
5855 perf_output_put(handle, raw->size);
5858 __output_custom(handle, frag->copy,
5859 frag->data, frag->size);
5861 __output_copy(handle, frag->data,
5864 if (perf_raw_frag_last(frag))
5869 __output_skip(handle, NULL, frag->pad);
5875 .size = sizeof(u32),
5878 perf_output_put(handle, raw);
5882 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5883 if (data->br_stack) {
5886 size = data->br_stack->nr
5887 * sizeof(struct perf_branch_entry);
5889 perf_output_put(handle, data->br_stack->nr);
5890 perf_output_copy(handle, data->br_stack->entries, size);
5893 * we always store at least the value of nr
5896 perf_output_put(handle, nr);
5900 if (sample_type & PERF_SAMPLE_REGS_USER) {
5901 u64 abi = data->regs_user.abi;
5904 * If there are no regs to dump, notice it through
5905 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5907 perf_output_put(handle, abi);
5910 u64 mask = event->attr.sample_regs_user;
5911 perf_output_sample_regs(handle,
5912 data->regs_user.regs,
5917 if (sample_type & PERF_SAMPLE_STACK_USER) {
5918 perf_output_sample_ustack(handle,
5919 data->stack_user_size,
5920 data->regs_user.regs);
5923 if (sample_type & PERF_SAMPLE_WEIGHT)
5924 perf_output_put(handle, data->weight);
5926 if (sample_type & PERF_SAMPLE_DATA_SRC)
5927 perf_output_put(handle, data->data_src.val);
5929 if (sample_type & PERF_SAMPLE_TRANSACTION)
5930 perf_output_put(handle, data->txn);
5932 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5933 u64 abi = data->regs_intr.abi;
5935 * If there are no regs to dump, notice it through
5936 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5938 perf_output_put(handle, abi);
5941 u64 mask = event->attr.sample_regs_intr;
5943 perf_output_sample_regs(handle,
5944 data->regs_intr.regs,
5949 if (!event->attr.watermark) {
5950 int wakeup_events = event->attr.wakeup_events;
5952 if (wakeup_events) {
5953 struct ring_buffer *rb = handle->rb;
5954 int events = local_inc_return(&rb->events);
5956 if (events >= wakeup_events) {
5957 local_sub(wakeup_events, &rb->events);
5958 local_inc(&rb->wakeup);
5964 void perf_prepare_sample(struct perf_event_header *header,
5965 struct perf_sample_data *data,
5966 struct perf_event *event,
5967 struct pt_regs *regs)
5969 u64 sample_type = event->attr.sample_type;
5971 header->type = PERF_RECORD_SAMPLE;
5972 header->size = sizeof(*header) + event->header_size;
5975 header->misc |= perf_misc_flags(regs);
5977 __perf_event_header__init_id(header, data, event);
5979 if (sample_type & PERF_SAMPLE_IP)
5980 data->ip = perf_instruction_pointer(regs);
5982 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5985 data->callchain = perf_callchain(event, regs);
5987 if (data->callchain)
5988 size += data->callchain->nr;
5990 header->size += size * sizeof(u64);
5993 if (sample_type & PERF_SAMPLE_RAW) {
5994 struct perf_raw_record *raw = data->raw;
5998 struct perf_raw_frag *frag = &raw->frag;
6003 if (perf_raw_frag_last(frag))
6008 size = round_up(sum + sizeof(u32), sizeof(u64));
6009 raw->size = size - sizeof(u32);
6010 frag->pad = raw->size - sum;
6015 header->size += size;
6018 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6019 int size = sizeof(u64); /* nr */
6020 if (data->br_stack) {
6021 size += data->br_stack->nr
6022 * sizeof(struct perf_branch_entry);
6024 header->size += size;
6027 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6028 perf_sample_regs_user(&data->regs_user, regs,
6029 &data->regs_user_copy);
6031 if (sample_type & PERF_SAMPLE_REGS_USER) {
6032 /* regs dump ABI info */
6033 int size = sizeof(u64);
6035 if (data->regs_user.regs) {
6036 u64 mask = event->attr.sample_regs_user;
6037 size += hweight64(mask) * sizeof(u64);
6040 header->size += size;
6043 if (sample_type & PERF_SAMPLE_STACK_USER) {
6045 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6046 * processed as the last one or have additional check added
6047 * in case new sample type is added, because we could eat
6048 * up the rest of the sample size.
6050 u16 stack_size = event->attr.sample_stack_user;
6051 u16 size = sizeof(u64);
6053 stack_size = perf_sample_ustack_size(stack_size, header->size,
6054 data->regs_user.regs);
6057 * If there is something to dump, add space for the dump
6058 * itself and for the field that tells the dynamic size,
6059 * which is how many have been actually dumped.
6062 size += sizeof(u64) + stack_size;
6064 data->stack_user_size = stack_size;
6065 header->size += size;
6068 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6069 /* regs dump ABI info */
6070 int size = sizeof(u64);
6072 perf_sample_regs_intr(&data->regs_intr, regs);
6074 if (data->regs_intr.regs) {
6075 u64 mask = event->attr.sample_regs_intr;
6077 size += hweight64(mask) * sizeof(u64);
6080 header->size += size;
6084 static void __always_inline
6085 __perf_event_output(struct perf_event *event,
6086 struct perf_sample_data *data,
6087 struct pt_regs *regs,
6088 int (*output_begin)(struct perf_output_handle *,
6089 struct perf_event *,
6092 struct perf_output_handle handle;
6093 struct perf_event_header header;
6095 /* protect the callchain buffers */
6098 perf_prepare_sample(&header, data, event, regs);
6100 if (output_begin(&handle, event, header.size))
6103 perf_output_sample(&handle, &header, data, event);
6105 perf_output_end(&handle);
6112 perf_event_output_forward(struct perf_event *event,
6113 struct perf_sample_data *data,
6114 struct pt_regs *regs)
6116 __perf_event_output(event, data, regs, perf_output_begin_forward);
6120 perf_event_output_backward(struct perf_event *event,
6121 struct perf_sample_data *data,
6122 struct pt_regs *regs)
6124 __perf_event_output(event, data, regs, perf_output_begin_backward);
6128 perf_event_output(struct perf_event *event,
6129 struct perf_sample_data *data,
6130 struct pt_regs *regs)
6132 __perf_event_output(event, data, regs, perf_output_begin);
6139 struct perf_read_event {
6140 struct perf_event_header header;
6147 perf_event_read_event(struct perf_event *event,
6148 struct task_struct *task)
6150 struct perf_output_handle handle;
6151 struct perf_sample_data sample;
6152 struct perf_read_event read_event = {
6154 .type = PERF_RECORD_READ,
6156 .size = sizeof(read_event) + event->read_size,
6158 .pid = perf_event_pid(event, task),
6159 .tid = perf_event_tid(event, task),
6163 perf_event_header__init_id(&read_event.header, &sample, event);
6164 ret = perf_output_begin(&handle, event, read_event.header.size);
6168 perf_output_put(&handle, read_event);
6169 perf_output_read(&handle, event);
6170 perf_event__output_id_sample(event, &handle, &sample);
6172 perf_output_end(&handle);
6175 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6178 perf_iterate_ctx(struct perf_event_context *ctx,
6179 perf_iterate_f output,
6180 void *data, bool all)
6182 struct perf_event *event;
6184 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6186 if (event->state < PERF_EVENT_STATE_INACTIVE)
6188 if (!event_filter_match(event))
6192 output(event, data);
6196 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6198 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6199 struct perf_event *event;
6201 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6203 * Skip events that are not fully formed yet; ensure that
6204 * if we observe event->ctx, both event and ctx will be
6205 * complete enough. See perf_install_in_context().
6207 if (!smp_load_acquire(&event->ctx))
6210 if (event->state < PERF_EVENT_STATE_INACTIVE)
6212 if (!event_filter_match(event))
6214 output(event, data);
6219 * Iterate all events that need to receive side-band events.
6221 * For new callers; ensure that account_pmu_sb_event() includes
6222 * your event, otherwise it might not get delivered.
6225 perf_iterate_sb(perf_iterate_f output, void *data,
6226 struct perf_event_context *task_ctx)
6228 struct perf_event_context *ctx;
6235 * If we have task_ctx != NULL we only notify the task context itself.
6236 * The task_ctx is set only for EXIT events before releasing task
6240 perf_iterate_ctx(task_ctx, output, data, false);
6244 perf_iterate_sb_cpu(output, data);
6246 for_each_task_context_nr(ctxn) {
6247 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6249 perf_iterate_ctx(ctx, output, data, false);
6257 * Clear all file-based filters at exec, they'll have to be
6258 * re-instated when/if these objects are mmapped again.
6260 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6262 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6263 struct perf_addr_filter *filter;
6264 unsigned int restart = 0, count = 0;
6265 unsigned long flags;
6267 if (!has_addr_filter(event))
6270 raw_spin_lock_irqsave(&ifh->lock, flags);
6271 list_for_each_entry(filter, &ifh->list, entry) {
6272 if (filter->inode) {
6273 event->addr_filters_offs[count] = 0;
6281 event->addr_filters_gen++;
6282 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6285 perf_event_stop(event, 1);
6288 void perf_event_exec(void)
6290 struct perf_event_context *ctx;
6294 for_each_task_context_nr(ctxn) {
6295 ctx = current->perf_event_ctxp[ctxn];
6299 perf_event_enable_on_exec(ctxn);
6301 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6307 struct remote_output {
6308 struct ring_buffer *rb;
6312 static void __perf_event_output_stop(struct perf_event *event, void *data)
6314 struct perf_event *parent = event->parent;
6315 struct remote_output *ro = data;
6316 struct ring_buffer *rb = ro->rb;
6317 struct stop_event_data sd = {
6321 if (!has_aux(event))
6328 * In case of inheritance, it will be the parent that links to the
6329 * ring-buffer, but it will be the child that's actually using it.
6331 * We are using event::rb to determine if the event should be stopped,
6332 * however this may race with ring_buffer_attach() (through set_output),
6333 * which will make us skip the event that actually needs to be stopped.
6334 * So ring_buffer_attach() has to stop an aux event before re-assigning
6337 if (rcu_dereference(parent->rb) == rb)
6338 ro->err = __perf_event_stop(&sd);
6341 static int __perf_pmu_output_stop(void *info)
6343 struct perf_event *event = info;
6344 struct pmu *pmu = event->pmu;
6345 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6346 struct remote_output ro = {
6351 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6352 if (cpuctx->task_ctx)
6353 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6360 static void perf_pmu_output_stop(struct perf_event *event)
6362 struct perf_event *iter;
6367 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6369 * For per-CPU events, we need to make sure that neither they
6370 * nor their children are running; for cpu==-1 events it's
6371 * sufficient to stop the event itself if it's active, since
6372 * it can't have children.
6376 cpu = READ_ONCE(iter->oncpu);
6381 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6382 if (err == -EAGAIN) {
6391 * task tracking -- fork/exit
6393 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6396 struct perf_task_event {
6397 struct task_struct *task;
6398 struct perf_event_context *task_ctx;
6401 struct perf_event_header header;
6411 static int perf_event_task_match(struct perf_event *event)
6413 return event->attr.comm || event->attr.mmap ||
6414 event->attr.mmap2 || event->attr.mmap_data ||
6418 static void perf_event_task_output(struct perf_event *event,
6421 struct perf_task_event *task_event = data;
6422 struct perf_output_handle handle;
6423 struct perf_sample_data sample;
6424 struct task_struct *task = task_event->task;
6425 int ret, size = task_event->event_id.header.size;
6427 if (!perf_event_task_match(event))
6430 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6432 ret = perf_output_begin(&handle, event,
6433 task_event->event_id.header.size);
6437 task_event->event_id.pid = perf_event_pid(event, task);
6438 task_event->event_id.ppid = perf_event_pid(event, current);
6440 task_event->event_id.tid = perf_event_tid(event, task);
6441 task_event->event_id.ptid = perf_event_tid(event, current);
6443 task_event->event_id.time = perf_event_clock(event);
6445 perf_output_put(&handle, task_event->event_id);
6447 perf_event__output_id_sample(event, &handle, &sample);
6449 perf_output_end(&handle);
6451 task_event->event_id.header.size = size;
6454 static void perf_event_task(struct task_struct *task,
6455 struct perf_event_context *task_ctx,
6458 struct perf_task_event task_event;
6460 if (!atomic_read(&nr_comm_events) &&
6461 !atomic_read(&nr_mmap_events) &&
6462 !atomic_read(&nr_task_events))
6465 task_event = (struct perf_task_event){
6467 .task_ctx = task_ctx,
6470 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6472 .size = sizeof(task_event.event_id),
6482 perf_iterate_sb(perf_event_task_output,
6487 void perf_event_fork(struct task_struct *task)
6489 perf_event_task(task, NULL, 1);
6496 struct perf_comm_event {
6497 struct task_struct *task;
6502 struct perf_event_header header;
6509 static int perf_event_comm_match(struct perf_event *event)
6511 return event->attr.comm;
6514 static void perf_event_comm_output(struct perf_event *event,
6517 struct perf_comm_event *comm_event = data;
6518 struct perf_output_handle handle;
6519 struct perf_sample_data sample;
6520 int size = comm_event->event_id.header.size;
6523 if (!perf_event_comm_match(event))
6526 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6527 ret = perf_output_begin(&handle, event,
6528 comm_event->event_id.header.size);
6533 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6534 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6536 perf_output_put(&handle, comm_event->event_id);
6537 __output_copy(&handle, comm_event->comm,
6538 comm_event->comm_size);
6540 perf_event__output_id_sample(event, &handle, &sample);
6542 perf_output_end(&handle);
6544 comm_event->event_id.header.size = size;
6547 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6549 char comm[TASK_COMM_LEN];
6552 memset(comm, 0, sizeof(comm));
6553 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6554 size = ALIGN(strlen(comm)+1, sizeof(u64));
6556 comm_event->comm = comm;
6557 comm_event->comm_size = size;
6559 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6561 perf_iterate_sb(perf_event_comm_output,
6566 void perf_event_comm(struct task_struct *task, bool exec)
6568 struct perf_comm_event comm_event;
6570 if (!atomic_read(&nr_comm_events))
6573 comm_event = (struct perf_comm_event){
6579 .type = PERF_RECORD_COMM,
6580 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6588 perf_event_comm_event(&comm_event);
6595 struct perf_mmap_event {
6596 struct vm_area_struct *vma;
6598 const char *file_name;
6606 struct perf_event_header header;
6616 static int perf_event_mmap_match(struct perf_event *event,
6619 struct perf_mmap_event *mmap_event = data;
6620 struct vm_area_struct *vma = mmap_event->vma;
6621 int executable = vma->vm_flags & VM_EXEC;
6623 return (!executable && event->attr.mmap_data) ||
6624 (executable && (event->attr.mmap || event->attr.mmap2));
6627 static void perf_event_mmap_output(struct perf_event *event,
6630 struct perf_mmap_event *mmap_event = data;
6631 struct perf_output_handle handle;
6632 struct perf_sample_data sample;
6633 int size = mmap_event->event_id.header.size;
6636 if (!perf_event_mmap_match(event, data))
6639 if (event->attr.mmap2) {
6640 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6641 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6642 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6643 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6644 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6645 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6646 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6649 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6650 ret = perf_output_begin(&handle, event,
6651 mmap_event->event_id.header.size);
6655 mmap_event->event_id.pid = perf_event_pid(event, current);
6656 mmap_event->event_id.tid = perf_event_tid(event, current);
6658 perf_output_put(&handle, mmap_event->event_id);
6660 if (event->attr.mmap2) {
6661 perf_output_put(&handle, mmap_event->maj);
6662 perf_output_put(&handle, mmap_event->min);
6663 perf_output_put(&handle, mmap_event->ino);
6664 perf_output_put(&handle, mmap_event->ino_generation);
6665 perf_output_put(&handle, mmap_event->prot);
6666 perf_output_put(&handle, mmap_event->flags);
6669 __output_copy(&handle, mmap_event->file_name,
6670 mmap_event->file_size);
6672 perf_event__output_id_sample(event, &handle, &sample);
6674 perf_output_end(&handle);
6676 mmap_event->event_id.header.size = size;
6679 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6681 struct vm_area_struct *vma = mmap_event->vma;
6682 struct file *file = vma->vm_file;
6683 int maj = 0, min = 0;
6684 u64 ino = 0, gen = 0;
6685 u32 prot = 0, flags = 0;
6691 if (vma->vm_flags & VM_READ)
6693 if (vma->vm_flags & VM_WRITE)
6695 if (vma->vm_flags & VM_EXEC)
6698 if (vma->vm_flags & VM_MAYSHARE)
6701 flags = MAP_PRIVATE;
6703 if (vma->vm_flags & VM_DENYWRITE)
6704 flags |= MAP_DENYWRITE;
6705 if (vma->vm_flags & VM_MAYEXEC)
6706 flags |= MAP_EXECUTABLE;
6707 if (vma->vm_flags & VM_LOCKED)
6708 flags |= MAP_LOCKED;
6709 if (vma->vm_flags & VM_HUGETLB)
6710 flags |= MAP_HUGETLB;
6713 struct inode *inode;
6716 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6722 * d_path() works from the end of the rb backwards, so we
6723 * need to add enough zero bytes after the string to handle
6724 * the 64bit alignment we do later.
6726 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6731 inode = file_inode(vma->vm_file);
6732 dev = inode->i_sb->s_dev;
6734 gen = inode->i_generation;
6740 if (vma->vm_ops && vma->vm_ops->name) {
6741 name = (char *) vma->vm_ops->name(vma);
6746 name = (char *)arch_vma_name(vma);
6750 if (vma->vm_start <= vma->vm_mm->start_brk &&
6751 vma->vm_end >= vma->vm_mm->brk) {
6755 if (vma->vm_start <= vma->vm_mm->start_stack &&
6756 vma->vm_end >= vma->vm_mm->start_stack) {
6766 strlcpy(tmp, name, sizeof(tmp));
6770 * Since our buffer works in 8 byte units we need to align our string
6771 * size to a multiple of 8. However, we must guarantee the tail end is
6772 * zero'd out to avoid leaking random bits to userspace.
6774 size = strlen(name)+1;
6775 while (!IS_ALIGNED(size, sizeof(u64)))
6776 name[size++] = '\0';
6778 mmap_event->file_name = name;
6779 mmap_event->file_size = size;
6780 mmap_event->maj = maj;
6781 mmap_event->min = min;
6782 mmap_event->ino = ino;
6783 mmap_event->ino_generation = gen;
6784 mmap_event->prot = prot;
6785 mmap_event->flags = flags;
6787 if (!(vma->vm_flags & VM_EXEC))
6788 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6790 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6792 perf_iterate_sb(perf_event_mmap_output,
6800 * Check whether inode and address range match filter criteria.
6802 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6803 struct file *file, unsigned long offset,
6806 if (filter->inode != file_inode(file))
6809 if (filter->offset > offset + size)
6812 if (filter->offset + filter->size < offset)
6818 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6820 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6821 struct vm_area_struct *vma = data;
6822 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6823 struct file *file = vma->vm_file;
6824 struct perf_addr_filter *filter;
6825 unsigned int restart = 0, count = 0;
6827 if (!has_addr_filter(event))
6833 raw_spin_lock_irqsave(&ifh->lock, flags);
6834 list_for_each_entry(filter, &ifh->list, entry) {
6835 if (perf_addr_filter_match(filter, file, off,
6836 vma->vm_end - vma->vm_start)) {
6837 event->addr_filters_offs[count] = vma->vm_start;
6845 event->addr_filters_gen++;
6846 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6849 perf_event_stop(event, 1);
6853 * Adjust all task's events' filters to the new vma
6855 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6857 struct perf_event_context *ctx;
6861 * Data tracing isn't supported yet and as such there is no need
6862 * to keep track of anything that isn't related to executable code:
6864 if (!(vma->vm_flags & VM_EXEC))
6868 for_each_task_context_nr(ctxn) {
6869 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6873 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6878 void perf_event_mmap(struct vm_area_struct *vma)
6880 struct perf_mmap_event mmap_event;
6882 if (!atomic_read(&nr_mmap_events))
6885 mmap_event = (struct perf_mmap_event){
6891 .type = PERF_RECORD_MMAP,
6892 .misc = PERF_RECORD_MISC_USER,
6897 .start = vma->vm_start,
6898 .len = vma->vm_end - vma->vm_start,
6899 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6901 /* .maj (attr_mmap2 only) */
6902 /* .min (attr_mmap2 only) */
6903 /* .ino (attr_mmap2 only) */
6904 /* .ino_generation (attr_mmap2 only) */
6905 /* .prot (attr_mmap2 only) */
6906 /* .flags (attr_mmap2 only) */
6909 perf_addr_filters_adjust(vma);
6910 perf_event_mmap_event(&mmap_event);
6913 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6914 unsigned long size, u64 flags)
6916 struct perf_output_handle handle;
6917 struct perf_sample_data sample;
6918 struct perf_aux_event {
6919 struct perf_event_header header;
6925 .type = PERF_RECORD_AUX,
6927 .size = sizeof(rec),
6935 perf_event_header__init_id(&rec.header, &sample, event);
6936 ret = perf_output_begin(&handle, event, rec.header.size);
6941 perf_output_put(&handle, rec);
6942 perf_event__output_id_sample(event, &handle, &sample);
6944 perf_output_end(&handle);
6948 * Lost/dropped samples logging
6950 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6952 struct perf_output_handle handle;
6953 struct perf_sample_data sample;
6957 struct perf_event_header header;
6959 } lost_samples_event = {
6961 .type = PERF_RECORD_LOST_SAMPLES,
6963 .size = sizeof(lost_samples_event),
6968 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6970 ret = perf_output_begin(&handle, event,
6971 lost_samples_event.header.size);
6975 perf_output_put(&handle, lost_samples_event);
6976 perf_event__output_id_sample(event, &handle, &sample);
6977 perf_output_end(&handle);
6981 * context_switch tracking
6984 struct perf_switch_event {
6985 struct task_struct *task;
6986 struct task_struct *next_prev;
6989 struct perf_event_header header;
6995 static int perf_event_switch_match(struct perf_event *event)
6997 return event->attr.context_switch;
7000 static void perf_event_switch_output(struct perf_event *event, void *data)
7002 struct perf_switch_event *se = data;
7003 struct perf_output_handle handle;
7004 struct perf_sample_data sample;
7007 if (!perf_event_switch_match(event))
7010 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7011 if (event->ctx->task) {
7012 se->event_id.header.type = PERF_RECORD_SWITCH;
7013 se->event_id.header.size = sizeof(se->event_id.header);
7015 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7016 se->event_id.header.size = sizeof(se->event_id);
7017 se->event_id.next_prev_pid =
7018 perf_event_pid(event, se->next_prev);
7019 se->event_id.next_prev_tid =
7020 perf_event_tid(event, se->next_prev);
7023 perf_event_header__init_id(&se->event_id.header, &sample, event);
7025 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7029 if (event->ctx->task)
7030 perf_output_put(&handle, se->event_id.header);
7032 perf_output_put(&handle, se->event_id);
7034 perf_event__output_id_sample(event, &handle, &sample);
7036 perf_output_end(&handle);
7039 static void perf_event_switch(struct task_struct *task,
7040 struct task_struct *next_prev, bool sched_in)
7042 struct perf_switch_event switch_event;
7044 /* N.B. caller checks nr_switch_events != 0 */
7046 switch_event = (struct perf_switch_event){
7048 .next_prev = next_prev,
7052 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7055 /* .next_prev_pid */
7056 /* .next_prev_tid */
7060 perf_iterate_sb(perf_event_switch_output,
7066 * IRQ throttle logging
7069 static void perf_log_throttle(struct perf_event *event, int enable)
7071 struct perf_output_handle handle;
7072 struct perf_sample_data sample;
7076 struct perf_event_header header;
7080 } throttle_event = {
7082 .type = PERF_RECORD_THROTTLE,
7084 .size = sizeof(throttle_event),
7086 .time = perf_event_clock(event),
7087 .id = primary_event_id(event),
7088 .stream_id = event->id,
7092 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7094 perf_event_header__init_id(&throttle_event.header, &sample, event);
7096 ret = perf_output_begin(&handle, event,
7097 throttle_event.header.size);
7101 perf_output_put(&handle, throttle_event);
7102 perf_event__output_id_sample(event, &handle, &sample);
7103 perf_output_end(&handle);
7106 static void perf_log_itrace_start(struct perf_event *event)
7108 struct perf_output_handle handle;
7109 struct perf_sample_data sample;
7110 struct perf_aux_event {
7111 struct perf_event_header header;
7118 event = event->parent;
7120 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7121 event->hw.itrace_started)
7124 rec.header.type = PERF_RECORD_ITRACE_START;
7125 rec.header.misc = 0;
7126 rec.header.size = sizeof(rec);
7127 rec.pid = perf_event_pid(event, current);
7128 rec.tid = perf_event_tid(event, current);
7130 perf_event_header__init_id(&rec.header, &sample, event);
7131 ret = perf_output_begin(&handle, event, rec.header.size);
7136 perf_output_put(&handle, rec);
7137 perf_event__output_id_sample(event, &handle, &sample);
7139 perf_output_end(&handle);
7143 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7145 struct hw_perf_event *hwc = &event->hw;
7149 seq = __this_cpu_read(perf_throttled_seq);
7150 if (seq != hwc->interrupts_seq) {
7151 hwc->interrupts_seq = seq;
7152 hwc->interrupts = 1;
7155 if (unlikely(throttle
7156 && hwc->interrupts >= max_samples_per_tick)) {
7157 __this_cpu_inc(perf_throttled_count);
7158 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7159 hwc->interrupts = MAX_INTERRUPTS;
7160 perf_log_throttle(event, 0);
7165 if (event->attr.freq) {
7166 u64 now = perf_clock();
7167 s64 delta = now - hwc->freq_time_stamp;
7169 hwc->freq_time_stamp = now;
7171 if (delta > 0 && delta < 2*TICK_NSEC)
7172 perf_adjust_period(event, delta, hwc->last_period, true);
7178 int perf_event_account_interrupt(struct perf_event *event)
7180 return __perf_event_account_interrupt(event, 1);
7184 * Generic event overflow handling, sampling.
7187 static int __perf_event_overflow(struct perf_event *event,
7188 int throttle, struct perf_sample_data *data,
7189 struct pt_regs *regs)
7191 int events = atomic_read(&event->event_limit);
7195 * Non-sampling counters might still use the PMI to fold short
7196 * hardware counters, ignore those.
7198 if (unlikely(!is_sampling_event(event)))
7201 ret = __perf_event_account_interrupt(event, throttle);
7204 * XXX event_limit might not quite work as expected on inherited
7208 event->pending_kill = POLL_IN;
7209 if (events && atomic_dec_and_test(&event->event_limit)) {
7211 event->pending_kill = POLL_HUP;
7213 perf_event_disable_inatomic(event);
7216 READ_ONCE(event->overflow_handler)(event, data, regs);
7218 if (*perf_event_fasync(event) && event->pending_kill) {
7219 event->pending_wakeup = 1;
7220 irq_work_queue(&event->pending);
7226 int perf_event_overflow(struct perf_event *event,
7227 struct perf_sample_data *data,
7228 struct pt_regs *regs)
7230 return __perf_event_overflow(event, 1, data, regs);
7234 * Generic software event infrastructure
7237 struct swevent_htable {
7238 struct swevent_hlist *swevent_hlist;
7239 struct mutex hlist_mutex;
7242 /* Recursion avoidance in each contexts */
7243 int recursion[PERF_NR_CONTEXTS];
7246 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7249 * We directly increment event->count and keep a second value in
7250 * event->hw.period_left to count intervals. This period event
7251 * is kept in the range [-sample_period, 0] so that we can use the
7255 u64 perf_swevent_set_period(struct perf_event *event)
7257 struct hw_perf_event *hwc = &event->hw;
7258 u64 period = hwc->last_period;
7262 hwc->last_period = hwc->sample_period;
7265 old = val = local64_read(&hwc->period_left);
7269 nr = div64_u64(period + val, period);
7270 offset = nr * period;
7272 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7278 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7279 struct perf_sample_data *data,
7280 struct pt_regs *regs)
7282 struct hw_perf_event *hwc = &event->hw;
7286 overflow = perf_swevent_set_period(event);
7288 if (hwc->interrupts == MAX_INTERRUPTS)
7291 for (; overflow; overflow--) {
7292 if (__perf_event_overflow(event, throttle,
7295 * We inhibit the overflow from happening when
7296 * hwc->interrupts == MAX_INTERRUPTS.
7304 static void perf_swevent_event(struct perf_event *event, u64 nr,
7305 struct perf_sample_data *data,
7306 struct pt_regs *regs)
7308 struct hw_perf_event *hwc = &event->hw;
7310 local64_add(nr, &event->count);
7315 if (!is_sampling_event(event))
7318 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7320 return perf_swevent_overflow(event, 1, data, regs);
7322 data->period = event->hw.last_period;
7324 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7325 return perf_swevent_overflow(event, 1, data, regs);
7327 if (local64_add_negative(nr, &hwc->period_left))
7330 perf_swevent_overflow(event, 0, data, regs);
7333 static int perf_exclude_event(struct perf_event *event,
7334 struct pt_regs *regs)
7336 if (event->hw.state & PERF_HES_STOPPED)
7340 if (event->attr.exclude_user && user_mode(regs))
7343 if (event->attr.exclude_kernel && !user_mode(regs))
7350 static int perf_swevent_match(struct perf_event *event,
7351 enum perf_type_id type,
7353 struct perf_sample_data *data,
7354 struct pt_regs *regs)
7356 if (event->attr.type != type)
7359 if (event->attr.config != event_id)
7362 if (perf_exclude_event(event, regs))
7368 static inline u64 swevent_hash(u64 type, u32 event_id)
7370 u64 val = event_id | (type << 32);
7372 return hash_64(val, SWEVENT_HLIST_BITS);
7375 static inline struct hlist_head *
7376 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7378 u64 hash = swevent_hash(type, event_id);
7380 return &hlist->heads[hash];
7383 /* For the read side: events when they trigger */
7384 static inline struct hlist_head *
7385 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7387 struct swevent_hlist *hlist;
7389 hlist = rcu_dereference(swhash->swevent_hlist);
7393 return __find_swevent_head(hlist, type, event_id);
7396 /* For the event head insertion and removal in the hlist */
7397 static inline struct hlist_head *
7398 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7400 struct swevent_hlist *hlist;
7401 u32 event_id = event->attr.config;
7402 u64 type = event->attr.type;
7405 * Event scheduling is always serialized against hlist allocation
7406 * and release. Which makes the protected version suitable here.
7407 * The context lock guarantees that.
7409 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7410 lockdep_is_held(&event->ctx->lock));
7414 return __find_swevent_head(hlist, type, event_id);
7417 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7419 struct perf_sample_data *data,
7420 struct pt_regs *regs)
7422 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7423 struct perf_event *event;
7424 struct hlist_head *head;
7427 head = find_swevent_head_rcu(swhash, type, event_id);
7431 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7432 if (perf_swevent_match(event, type, event_id, data, regs))
7433 perf_swevent_event(event, nr, data, regs);
7439 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7441 int perf_swevent_get_recursion_context(void)
7443 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7445 return get_recursion_context(swhash->recursion);
7447 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7449 void perf_swevent_put_recursion_context(int rctx)
7451 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7453 put_recursion_context(swhash->recursion, rctx);
7456 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7458 struct perf_sample_data data;
7460 if (WARN_ON_ONCE(!regs))
7463 perf_sample_data_init(&data, addr, 0);
7464 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7467 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7471 preempt_disable_notrace();
7472 rctx = perf_swevent_get_recursion_context();
7473 if (unlikely(rctx < 0))
7476 ___perf_sw_event(event_id, nr, regs, addr);
7478 perf_swevent_put_recursion_context(rctx);
7480 preempt_enable_notrace();
7483 static void perf_swevent_read(struct perf_event *event)
7487 static int perf_swevent_add(struct perf_event *event, int flags)
7489 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7490 struct hw_perf_event *hwc = &event->hw;
7491 struct hlist_head *head;
7493 if (is_sampling_event(event)) {
7494 hwc->last_period = hwc->sample_period;
7495 perf_swevent_set_period(event);
7498 hwc->state = !(flags & PERF_EF_START);
7500 head = find_swevent_head(swhash, event);
7501 if (WARN_ON_ONCE(!head))
7504 hlist_add_head_rcu(&event->hlist_entry, head);
7505 perf_event_update_userpage(event);
7510 static void perf_swevent_del(struct perf_event *event, int flags)
7512 hlist_del_rcu(&event->hlist_entry);
7515 static void perf_swevent_start(struct perf_event *event, int flags)
7517 event->hw.state = 0;
7520 static void perf_swevent_stop(struct perf_event *event, int flags)
7522 event->hw.state = PERF_HES_STOPPED;
7525 /* Deref the hlist from the update side */
7526 static inline struct swevent_hlist *
7527 swevent_hlist_deref(struct swevent_htable *swhash)
7529 return rcu_dereference_protected(swhash->swevent_hlist,
7530 lockdep_is_held(&swhash->hlist_mutex));
7533 static void swevent_hlist_release(struct swevent_htable *swhash)
7535 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7540 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7541 kfree_rcu(hlist, rcu_head);
7544 static void swevent_hlist_put_cpu(int cpu)
7546 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7548 mutex_lock(&swhash->hlist_mutex);
7550 if (!--swhash->hlist_refcount)
7551 swevent_hlist_release(swhash);
7553 mutex_unlock(&swhash->hlist_mutex);
7556 static void swevent_hlist_put(void)
7560 for_each_possible_cpu(cpu)
7561 swevent_hlist_put_cpu(cpu);
7564 static int swevent_hlist_get_cpu(int cpu)
7566 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7569 mutex_lock(&swhash->hlist_mutex);
7570 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7571 struct swevent_hlist *hlist;
7573 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7578 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7580 swhash->hlist_refcount++;
7582 mutex_unlock(&swhash->hlist_mutex);
7587 static int swevent_hlist_get(void)
7589 int err, cpu, failed_cpu;
7592 for_each_possible_cpu(cpu) {
7593 err = swevent_hlist_get_cpu(cpu);
7603 for_each_possible_cpu(cpu) {
7604 if (cpu == failed_cpu)
7606 swevent_hlist_put_cpu(cpu);
7613 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7615 static void sw_perf_event_destroy(struct perf_event *event)
7617 u64 event_id = event->attr.config;
7619 WARN_ON(event->parent);
7621 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7622 swevent_hlist_put();
7625 static int perf_swevent_init(struct perf_event *event)
7627 u64 event_id = event->attr.config;
7629 if (event->attr.type != PERF_TYPE_SOFTWARE)
7633 * no branch sampling for software events
7635 if (has_branch_stack(event))
7639 case PERF_COUNT_SW_CPU_CLOCK:
7640 case PERF_COUNT_SW_TASK_CLOCK:
7647 if (event_id >= PERF_COUNT_SW_MAX)
7650 if (!event->parent) {
7653 err = swevent_hlist_get();
7657 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7658 event->destroy = sw_perf_event_destroy;
7664 static struct pmu perf_swevent = {
7665 .task_ctx_nr = perf_sw_context,
7667 .capabilities = PERF_PMU_CAP_NO_NMI,
7669 .event_init = perf_swevent_init,
7670 .add = perf_swevent_add,
7671 .del = perf_swevent_del,
7672 .start = perf_swevent_start,
7673 .stop = perf_swevent_stop,
7674 .read = perf_swevent_read,
7677 #ifdef CONFIG_EVENT_TRACING
7679 static int perf_tp_filter_match(struct perf_event *event,
7680 struct perf_sample_data *data)
7682 void *record = data->raw->frag.data;
7684 /* only top level events have filters set */
7686 event = event->parent;
7688 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7693 static int perf_tp_event_match(struct perf_event *event,
7694 struct perf_sample_data *data,
7695 struct pt_regs *regs)
7697 if (event->hw.state & PERF_HES_STOPPED)
7700 * All tracepoints are from kernel-space.
7702 if (event->attr.exclude_kernel)
7705 if (!perf_tp_filter_match(event, data))
7711 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7712 struct trace_event_call *call, u64 count,
7713 struct pt_regs *regs, struct hlist_head *head,
7714 struct task_struct *task)
7716 struct bpf_prog *prog = call->prog;
7719 *(struct pt_regs **)raw_data = regs;
7720 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7721 perf_swevent_put_recursion_context(rctx);
7725 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7728 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7730 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7731 struct pt_regs *regs, struct hlist_head *head, int rctx,
7732 struct task_struct *task)
7734 struct perf_sample_data data;
7735 struct perf_event *event;
7737 struct perf_raw_record raw = {
7744 perf_sample_data_init(&data, 0, 0);
7747 perf_trace_buf_update(record, event_type);
7749 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7750 if (perf_tp_event_match(event, &data, regs))
7751 perf_swevent_event(event, count, &data, regs);
7755 * If we got specified a target task, also iterate its context and
7756 * deliver this event there too.
7758 if (task && task != current) {
7759 struct perf_event_context *ctx;
7760 struct trace_entry *entry = record;
7763 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7767 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7768 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7770 if (event->attr.config != entry->type)
7772 if (perf_tp_event_match(event, &data, regs))
7773 perf_swevent_event(event, count, &data, regs);
7779 perf_swevent_put_recursion_context(rctx);
7781 EXPORT_SYMBOL_GPL(perf_tp_event);
7783 static void tp_perf_event_destroy(struct perf_event *event)
7785 perf_trace_destroy(event);
7788 static int perf_tp_event_init(struct perf_event *event)
7792 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7796 * no branch sampling for tracepoint events
7798 if (has_branch_stack(event))
7801 err = perf_trace_init(event);
7805 event->destroy = tp_perf_event_destroy;
7810 static struct pmu perf_tracepoint = {
7811 .task_ctx_nr = perf_sw_context,
7813 .event_init = perf_tp_event_init,
7814 .add = perf_trace_add,
7815 .del = perf_trace_del,
7816 .start = perf_swevent_start,
7817 .stop = perf_swevent_stop,
7818 .read = perf_swevent_read,
7821 static inline void perf_tp_register(void)
7823 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7826 static void perf_event_free_filter(struct perf_event *event)
7828 ftrace_profile_free_filter(event);
7831 #ifdef CONFIG_BPF_SYSCALL
7832 static void bpf_overflow_handler(struct perf_event *event,
7833 struct perf_sample_data *data,
7834 struct pt_regs *regs)
7836 struct bpf_perf_event_data_kern ctx = {
7843 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7846 ret = BPF_PROG_RUN(event->prog, &ctx);
7849 __this_cpu_dec(bpf_prog_active);
7854 event->orig_overflow_handler(event, data, regs);
7857 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7859 struct bpf_prog *prog;
7861 if (event->overflow_handler_context)
7862 /* hw breakpoint or kernel counter */
7868 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
7870 return PTR_ERR(prog);
7873 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
7874 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
7878 static void perf_event_free_bpf_handler(struct perf_event *event)
7880 struct bpf_prog *prog = event->prog;
7885 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
7890 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7894 static void perf_event_free_bpf_handler(struct perf_event *event)
7899 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7901 bool is_kprobe, is_tracepoint;
7902 struct bpf_prog *prog;
7904 if (event->attr.type == PERF_TYPE_HARDWARE ||
7905 event->attr.type == PERF_TYPE_SOFTWARE)
7906 return perf_event_set_bpf_handler(event, prog_fd);
7908 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7911 if (event->tp_event->prog)
7914 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7915 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7916 if (!is_kprobe && !is_tracepoint)
7917 /* bpf programs can only be attached to u/kprobe or tracepoint */
7920 prog = bpf_prog_get(prog_fd);
7922 return PTR_ERR(prog);
7924 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7925 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7926 /* valid fd, but invalid bpf program type */
7931 if (is_tracepoint) {
7932 int off = trace_event_get_offsets(event->tp_event);
7934 if (prog->aux->max_ctx_offset > off) {
7939 event->tp_event->prog = prog;
7944 static void perf_event_free_bpf_prog(struct perf_event *event)
7946 struct bpf_prog *prog;
7948 perf_event_free_bpf_handler(event);
7950 if (!event->tp_event)
7953 prog = event->tp_event->prog;
7955 event->tp_event->prog = NULL;
7962 static inline void perf_tp_register(void)
7966 static void perf_event_free_filter(struct perf_event *event)
7970 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7975 static void perf_event_free_bpf_prog(struct perf_event *event)
7978 #endif /* CONFIG_EVENT_TRACING */
7980 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7981 void perf_bp_event(struct perf_event *bp, void *data)
7983 struct perf_sample_data sample;
7984 struct pt_regs *regs = data;
7986 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7988 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7989 perf_swevent_event(bp, 1, &sample, regs);
7994 * Allocate a new address filter
7996 static struct perf_addr_filter *
7997 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7999 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8000 struct perf_addr_filter *filter;
8002 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8006 INIT_LIST_HEAD(&filter->entry);
8007 list_add_tail(&filter->entry, filters);
8012 static void free_filters_list(struct list_head *filters)
8014 struct perf_addr_filter *filter, *iter;
8016 list_for_each_entry_safe(filter, iter, filters, entry) {
8018 iput(filter->inode);
8019 list_del(&filter->entry);
8025 * Free existing address filters and optionally install new ones
8027 static void perf_addr_filters_splice(struct perf_event *event,
8028 struct list_head *head)
8030 unsigned long flags;
8033 if (!has_addr_filter(event))
8036 /* don't bother with children, they don't have their own filters */
8040 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8042 list_splice_init(&event->addr_filters.list, &list);
8044 list_splice(head, &event->addr_filters.list);
8046 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8048 free_filters_list(&list);
8052 * Scan through mm's vmas and see if one of them matches the
8053 * @filter; if so, adjust filter's address range.
8054 * Called with mm::mmap_sem down for reading.
8056 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8057 struct mm_struct *mm)
8059 struct vm_area_struct *vma;
8061 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8062 struct file *file = vma->vm_file;
8063 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8064 unsigned long vma_size = vma->vm_end - vma->vm_start;
8069 if (!perf_addr_filter_match(filter, file, off, vma_size))
8072 return vma->vm_start;
8079 * Update event's address range filters based on the
8080 * task's existing mappings, if any.
8082 static void perf_event_addr_filters_apply(struct perf_event *event)
8084 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8085 struct task_struct *task = READ_ONCE(event->ctx->task);
8086 struct perf_addr_filter *filter;
8087 struct mm_struct *mm = NULL;
8088 unsigned int count = 0;
8089 unsigned long flags;
8092 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8093 * will stop on the parent's child_mutex that our caller is also holding
8095 if (task == TASK_TOMBSTONE)
8098 if (!ifh->nr_file_filters)
8101 mm = get_task_mm(event->ctx->task);
8105 down_read(&mm->mmap_sem);
8107 raw_spin_lock_irqsave(&ifh->lock, flags);
8108 list_for_each_entry(filter, &ifh->list, entry) {
8109 event->addr_filters_offs[count] = 0;
8112 * Adjust base offset if the filter is associated to a binary
8113 * that needs to be mapped:
8116 event->addr_filters_offs[count] =
8117 perf_addr_filter_apply(filter, mm);
8122 event->addr_filters_gen++;
8123 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8125 up_read(&mm->mmap_sem);
8130 perf_event_stop(event, 1);
8134 * Address range filtering: limiting the data to certain
8135 * instruction address ranges. Filters are ioctl()ed to us from
8136 * userspace as ascii strings.
8138 * Filter string format:
8141 * where ACTION is one of the
8142 * * "filter": limit the trace to this region
8143 * * "start": start tracing from this address
8144 * * "stop": stop tracing at this address/region;
8146 * * for kernel addresses: <start address>[/<size>]
8147 * * for object files: <start address>[/<size>]@</path/to/object/file>
8149 * if <size> is not specified, the range is treated as a single address.
8163 IF_STATE_ACTION = 0,
8168 static const match_table_t if_tokens = {
8169 { IF_ACT_FILTER, "filter" },
8170 { IF_ACT_START, "start" },
8171 { IF_ACT_STOP, "stop" },
8172 { IF_SRC_FILE, "%u/%u@%s" },
8173 { IF_SRC_KERNEL, "%u/%u" },
8174 { IF_SRC_FILEADDR, "%u@%s" },
8175 { IF_SRC_KERNELADDR, "%u" },
8176 { IF_ACT_NONE, NULL },
8180 * Address filter string parser
8183 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8184 struct list_head *filters)
8186 struct perf_addr_filter *filter = NULL;
8187 char *start, *orig, *filename = NULL;
8189 substring_t args[MAX_OPT_ARGS];
8190 int state = IF_STATE_ACTION, token;
8191 unsigned int kernel = 0;
8194 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8198 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8204 /* filter definition begins */
8205 if (state == IF_STATE_ACTION) {
8206 filter = perf_addr_filter_new(event, filters);
8211 token = match_token(start, if_tokens, args);
8218 if (state != IF_STATE_ACTION)
8221 state = IF_STATE_SOURCE;
8224 case IF_SRC_KERNELADDR:
8228 case IF_SRC_FILEADDR:
8230 if (state != IF_STATE_SOURCE)
8233 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8237 ret = kstrtoul(args[0].from, 0, &filter->offset);
8241 if (filter->range) {
8243 ret = kstrtoul(args[1].from, 0, &filter->size);
8248 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8249 int fpos = filter->range ? 2 : 1;
8251 filename = match_strdup(&args[fpos]);
8258 state = IF_STATE_END;
8266 * Filter definition is fully parsed, validate and install it.
8267 * Make sure that it doesn't contradict itself or the event's
8270 if (state == IF_STATE_END) {
8272 if (kernel && event->attr.exclude_kernel)
8280 * For now, we only support file-based filters
8281 * in per-task events; doing so for CPU-wide
8282 * events requires additional context switching
8283 * trickery, since same object code will be
8284 * mapped at different virtual addresses in
8285 * different processes.
8288 if (!event->ctx->task)
8289 goto fail_free_name;
8291 /* look up the path and grab its inode */
8292 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8294 goto fail_free_name;
8296 filter->inode = igrab(d_inode(path.dentry));
8302 if (!filter->inode ||
8303 !S_ISREG(filter->inode->i_mode))
8304 /* free_filters_list() will iput() */
8307 event->addr_filters.nr_file_filters++;
8310 /* ready to consume more filters */
8311 state = IF_STATE_ACTION;
8316 if (state != IF_STATE_ACTION)
8326 free_filters_list(filters);
8333 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8339 * Since this is called in perf_ioctl() path, we're already holding
8342 lockdep_assert_held(&event->ctx->mutex);
8344 if (WARN_ON_ONCE(event->parent))
8347 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8349 goto fail_clear_files;
8351 ret = event->pmu->addr_filters_validate(&filters);
8353 goto fail_free_filters;
8355 /* remove existing filters, if any */
8356 perf_addr_filters_splice(event, &filters);
8358 /* install new filters */
8359 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8364 free_filters_list(&filters);
8367 event->addr_filters.nr_file_filters = 0;
8372 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8377 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8378 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8379 !has_addr_filter(event))
8382 filter_str = strndup_user(arg, PAGE_SIZE);
8383 if (IS_ERR(filter_str))
8384 return PTR_ERR(filter_str);
8386 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8387 event->attr.type == PERF_TYPE_TRACEPOINT)
8388 ret = ftrace_profile_set_filter(event, event->attr.config,
8390 else if (has_addr_filter(event))
8391 ret = perf_event_set_addr_filter(event, filter_str);
8398 * hrtimer based swevent callback
8401 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8403 enum hrtimer_restart ret = HRTIMER_RESTART;
8404 struct perf_sample_data data;
8405 struct pt_regs *regs;
8406 struct perf_event *event;
8409 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8411 if (event->state != PERF_EVENT_STATE_ACTIVE)
8412 return HRTIMER_NORESTART;
8414 event->pmu->read(event);
8416 perf_sample_data_init(&data, 0, event->hw.last_period);
8417 regs = get_irq_regs();
8419 if (regs && !perf_exclude_event(event, regs)) {
8420 if (!(event->attr.exclude_idle && is_idle_task(current)))
8421 if (__perf_event_overflow(event, 1, &data, regs))
8422 ret = HRTIMER_NORESTART;
8425 period = max_t(u64, 10000, event->hw.sample_period);
8426 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8431 static void perf_swevent_start_hrtimer(struct perf_event *event)
8433 struct hw_perf_event *hwc = &event->hw;
8436 if (!is_sampling_event(event))
8439 period = local64_read(&hwc->period_left);
8444 local64_set(&hwc->period_left, 0);
8446 period = max_t(u64, 10000, hwc->sample_period);
8448 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8449 HRTIMER_MODE_REL_PINNED);
8452 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8454 struct hw_perf_event *hwc = &event->hw;
8456 if (is_sampling_event(event)) {
8457 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8458 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8460 hrtimer_cancel(&hwc->hrtimer);
8464 static void perf_swevent_init_hrtimer(struct perf_event *event)
8466 struct hw_perf_event *hwc = &event->hw;
8468 if (!is_sampling_event(event))
8471 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8472 hwc->hrtimer.function = perf_swevent_hrtimer;
8475 * Since hrtimers have a fixed rate, we can do a static freq->period
8476 * mapping and avoid the whole period adjust feedback stuff.
8478 if (event->attr.freq) {
8479 long freq = event->attr.sample_freq;
8481 event->attr.sample_period = NSEC_PER_SEC / freq;
8482 hwc->sample_period = event->attr.sample_period;
8483 local64_set(&hwc->period_left, hwc->sample_period);
8484 hwc->last_period = hwc->sample_period;
8485 event->attr.freq = 0;
8490 * Software event: cpu wall time clock
8493 static void cpu_clock_event_update(struct perf_event *event)
8498 now = local_clock();
8499 prev = local64_xchg(&event->hw.prev_count, now);
8500 local64_add(now - prev, &event->count);
8503 static void cpu_clock_event_start(struct perf_event *event, int flags)
8505 local64_set(&event->hw.prev_count, local_clock());
8506 perf_swevent_start_hrtimer(event);
8509 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8511 perf_swevent_cancel_hrtimer(event);
8512 cpu_clock_event_update(event);
8515 static int cpu_clock_event_add(struct perf_event *event, int flags)
8517 if (flags & PERF_EF_START)
8518 cpu_clock_event_start(event, flags);
8519 perf_event_update_userpage(event);
8524 static void cpu_clock_event_del(struct perf_event *event, int flags)
8526 cpu_clock_event_stop(event, flags);
8529 static void cpu_clock_event_read(struct perf_event *event)
8531 cpu_clock_event_update(event);
8534 static int cpu_clock_event_init(struct perf_event *event)
8536 if (event->attr.type != PERF_TYPE_SOFTWARE)
8539 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8543 * no branch sampling for software events
8545 if (has_branch_stack(event))
8548 perf_swevent_init_hrtimer(event);
8553 static struct pmu perf_cpu_clock = {
8554 .task_ctx_nr = perf_sw_context,
8556 .capabilities = PERF_PMU_CAP_NO_NMI,
8558 .event_init = cpu_clock_event_init,
8559 .add = cpu_clock_event_add,
8560 .del = cpu_clock_event_del,
8561 .start = cpu_clock_event_start,
8562 .stop = cpu_clock_event_stop,
8563 .read = cpu_clock_event_read,
8567 * Software event: task time clock
8570 static void task_clock_event_update(struct perf_event *event, u64 now)
8575 prev = local64_xchg(&event->hw.prev_count, now);
8577 local64_add(delta, &event->count);
8580 static void task_clock_event_start(struct perf_event *event, int flags)
8582 local64_set(&event->hw.prev_count, event->ctx->time);
8583 perf_swevent_start_hrtimer(event);
8586 static void task_clock_event_stop(struct perf_event *event, int flags)
8588 perf_swevent_cancel_hrtimer(event);
8589 task_clock_event_update(event, event->ctx->time);
8592 static int task_clock_event_add(struct perf_event *event, int flags)
8594 if (flags & PERF_EF_START)
8595 task_clock_event_start(event, flags);
8596 perf_event_update_userpage(event);
8601 static void task_clock_event_del(struct perf_event *event, int flags)
8603 task_clock_event_stop(event, PERF_EF_UPDATE);
8606 static void task_clock_event_read(struct perf_event *event)
8608 u64 now = perf_clock();
8609 u64 delta = now - event->ctx->timestamp;
8610 u64 time = event->ctx->time + delta;
8612 task_clock_event_update(event, time);
8615 static int task_clock_event_init(struct perf_event *event)
8617 if (event->attr.type != PERF_TYPE_SOFTWARE)
8620 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8624 * no branch sampling for software events
8626 if (has_branch_stack(event))
8629 perf_swevent_init_hrtimer(event);
8634 static struct pmu perf_task_clock = {
8635 .task_ctx_nr = perf_sw_context,
8637 .capabilities = PERF_PMU_CAP_NO_NMI,
8639 .event_init = task_clock_event_init,
8640 .add = task_clock_event_add,
8641 .del = task_clock_event_del,
8642 .start = task_clock_event_start,
8643 .stop = task_clock_event_stop,
8644 .read = task_clock_event_read,
8647 static void perf_pmu_nop_void(struct pmu *pmu)
8651 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8655 static int perf_pmu_nop_int(struct pmu *pmu)
8660 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8662 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8664 __this_cpu_write(nop_txn_flags, flags);
8666 if (flags & ~PERF_PMU_TXN_ADD)
8669 perf_pmu_disable(pmu);
8672 static int perf_pmu_commit_txn(struct pmu *pmu)
8674 unsigned int flags = __this_cpu_read(nop_txn_flags);
8676 __this_cpu_write(nop_txn_flags, 0);
8678 if (flags & ~PERF_PMU_TXN_ADD)
8681 perf_pmu_enable(pmu);
8685 static void perf_pmu_cancel_txn(struct pmu *pmu)
8687 unsigned int flags = __this_cpu_read(nop_txn_flags);
8689 __this_cpu_write(nop_txn_flags, 0);
8691 if (flags & ~PERF_PMU_TXN_ADD)
8694 perf_pmu_enable(pmu);
8697 static int perf_event_idx_default(struct perf_event *event)
8703 * Ensures all contexts with the same task_ctx_nr have the same
8704 * pmu_cpu_context too.
8706 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8713 list_for_each_entry(pmu, &pmus, entry) {
8714 if (pmu->task_ctx_nr == ctxn)
8715 return pmu->pmu_cpu_context;
8721 static void free_pmu_context(struct pmu *pmu)
8723 mutex_lock(&pmus_lock);
8724 free_percpu(pmu->pmu_cpu_context);
8725 mutex_unlock(&pmus_lock);
8729 * Let userspace know that this PMU supports address range filtering:
8731 static ssize_t nr_addr_filters_show(struct device *dev,
8732 struct device_attribute *attr,
8735 struct pmu *pmu = dev_get_drvdata(dev);
8737 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8739 DEVICE_ATTR_RO(nr_addr_filters);
8741 static struct idr pmu_idr;
8744 type_show(struct device *dev, struct device_attribute *attr, char *page)
8746 struct pmu *pmu = dev_get_drvdata(dev);
8748 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8750 static DEVICE_ATTR_RO(type);
8753 perf_event_mux_interval_ms_show(struct device *dev,
8754 struct device_attribute *attr,
8757 struct pmu *pmu = dev_get_drvdata(dev);
8759 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8762 static DEFINE_MUTEX(mux_interval_mutex);
8765 perf_event_mux_interval_ms_store(struct device *dev,
8766 struct device_attribute *attr,
8767 const char *buf, size_t count)
8769 struct pmu *pmu = dev_get_drvdata(dev);
8770 int timer, cpu, ret;
8772 ret = kstrtoint(buf, 0, &timer);
8779 /* same value, noting to do */
8780 if (timer == pmu->hrtimer_interval_ms)
8783 mutex_lock(&mux_interval_mutex);
8784 pmu->hrtimer_interval_ms = timer;
8786 /* update all cpuctx for this PMU */
8788 for_each_online_cpu(cpu) {
8789 struct perf_cpu_context *cpuctx;
8790 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8791 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8793 cpu_function_call(cpu,
8794 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8797 mutex_unlock(&mux_interval_mutex);
8801 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8803 static struct attribute *pmu_dev_attrs[] = {
8804 &dev_attr_type.attr,
8805 &dev_attr_perf_event_mux_interval_ms.attr,
8808 ATTRIBUTE_GROUPS(pmu_dev);
8810 static int pmu_bus_running;
8811 static struct bus_type pmu_bus = {
8812 .name = "event_source",
8813 .dev_groups = pmu_dev_groups,
8816 static void pmu_dev_release(struct device *dev)
8821 static int pmu_dev_alloc(struct pmu *pmu)
8825 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8829 pmu->dev->groups = pmu->attr_groups;
8830 device_initialize(pmu->dev);
8831 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8835 dev_set_drvdata(pmu->dev, pmu);
8836 pmu->dev->bus = &pmu_bus;
8837 pmu->dev->release = pmu_dev_release;
8838 ret = device_add(pmu->dev);
8842 /* For PMUs with address filters, throw in an extra attribute: */
8843 if (pmu->nr_addr_filters)
8844 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8853 device_del(pmu->dev);
8856 put_device(pmu->dev);
8860 static struct lock_class_key cpuctx_mutex;
8861 static struct lock_class_key cpuctx_lock;
8863 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8867 mutex_lock(&pmus_lock);
8869 pmu->pmu_disable_count = alloc_percpu(int);
8870 if (!pmu->pmu_disable_count)
8879 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8887 if (pmu_bus_running) {
8888 ret = pmu_dev_alloc(pmu);
8894 if (pmu->task_ctx_nr == perf_hw_context) {
8895 static int hw_context_taken = 0;
8898 * Other than systems with heterogeneous CPUs, it never makes
8899 * sense for two PMUs to share perf_hw_context. PMUs which are
8900 * uncore must use perf_invalid_context.
8902 if (WARN_ON_ONCE(hw_context_taken &&
8903 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8904 pmu->task_ctx_nr = perf_invalid_context;
8906 hw_context_taken = 1;
8909 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8910 if (pmu->pmu_cpu_context)
8911 goto got_cpu_context;
8914 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8915 if (!pmu->pmu_cpu_context)
8918 for_each_possible_cpu(cpu) {
8919 struct perf_cpu_context *cpuctx;
8921 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8922 __perf_event_init_context(&cpuctx->ctx);
8923 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8924 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8925 cpuctx->ctx.pmu = pmu;
8927 __perf_mux_hrtimer_init(cpuctx, cpu);
8931 if (!pmu->start_txn) {
8932 if (pmu->pmu_enable) {
8934 * If we have pmu_enable/pmu_disable calls, install
8935 * transaction stubs that use that to try and batch
8936 * hardware accesses.
8938 pmu->start_txn = perf_pmu_start_txn;
8939 pmu->commit_txn = perf_pmu_commit_txn;
8940 pmu->cancel_txn = perf_pmu_cancel_txn;
8942 pmu->start_txn = perf_pmu_nop_txn;
8943 pmu->commit_txn = perf_pmu_nop_int;
8944 pmu->cancel_txn = perf_pmu_nop_void;
8948 if (!pmu->pmu_enable) {
8949 pmu->pmu_enable = perf_pmu_nop_void;
8950 pmu->pmu_disable = perf_pmu_nop_void;
8953 if (!pmu->event_idx)
8954 pmu->event_idx = perf_event_idx_default;
8956 list_add_rcu(&pmu->entry, &pmus);
8957 atomic_set(&pmu->exclusive_cnt, 0);
8960 mutex_unlock(&pmus_lock);
8965 device_del(pmu->dev);
8966 put_device(pmu->dev);
8969 if (pmu->type >= PERF_TYPE_MAX)
8970 idr_remove(&pmu_idr, pmu->type);
8973 free_percpu(pmu->pmu_disable_count);
8976 EXPORT_SYMBOL_GPL(perf_pmu_register);
8978 void perf_pmu_unregister(struct pmu *pmu)
8982 mutex_lock(&pmus_lock);
8983 remove_device = pmu_bus_running;
8984 list_del_rcu(&pmu->entry);
8985 mutex_unlock(&pmus_lock);
8988 * We dereference the pmu list under both SRCU and regular RCU, so
8989 * synchronize against both of those.
8991 synchronize_srcu(&pmus_srcu);
8994 free_percpu(pmu->pmu_disable_count);
8995 if (pmu->type >= PERF_TYPE_MAX)
8996 idr_remove(&pmu_idr, pmu->type);
8997 if (remove_device) {
8998 if (pmu->nr_addr_filters)
8999 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9000 device_del(pmu->dev);
9001 put_device(pmu->dev);
9003 free_pmu_context(pmu);
9005 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9007 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9009 struct perf_event_context *ctx = NULL;
9012 if (!try_module_get(pmu->module))
9015 if (event->group_leader != event) {
9017 * This ctx->mutex can nest when we're called through
9018 * inheritance. See the perf_event_ctx_lock_nested() comment.
9020 ctx = perf_event_ctx_lock_nested(event->group_leader,
9021 SINGLE_DEPTH_NESTING);
9026 ret = pmu->event_init(event);
9029 perf_event_ctx_unlock(event->group_leader, ctx);
9032 module_put(pmu->module);
9037 static struct pmu *perf_init_event(struct perf_event *event)
9039 struct pmu *pmu = NULL;
9043 idx = srcu_read_lock(&pmus_srcu);
9045 /* Try parent's PMU first: */
9046 if (event->parent && event->parent->pmu) {
9047 pmu = event->parent->pmu;
9048 ret = perf_try_init_event(pmu, event);
9054 pmu = idr_find(&pmu_idr, event->attr.type);
9057 ret = perf_try_init_event(pmu, event);
9063 list_for_each_entry_rcu(pmu, &pmus, entry) {
9064 ret = perf_try_init_event(pmu, event);
9068 if (ret != -ENOENT) {
9073 pmu = ERR_PTR(-ENOENT);
9075 srcu_read_unlock(&pmus_srcu, idx);
9080 static void attach_sb_event(struct perf_event *event)
9082 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9084 raw_spin_lock(&pel->lock);
9085 list_add_rcu(&event->sb_list, &pel->list);
9086 raw_spin_unlock(&pel->lock);
9090 * We keep a list of all !task (and therefore per-cpu) events
9091 * that need to receive side-band records.
9093 * This avoids having to scan all the various PMU per-cpu contexts
9096 static void account_pmu_sb_event(struct perf_event *event)
9098 if (is_sb_event(event))
9099 attach_sb_event(event);
9102 static void account_event_cpu(struct perf_event *event, int cpu)
9107 if (is_cgroup_event(event))
9108 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9111 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9112 static void account_freq_event_nohz(void)
9114 #ifdef CONFIG_NO_HZ_FULL
9115 /* Lock so we don't race with concurrent unaccount */
9116 spin_lock(&nr_freq_lock);
9117 if (atomic_inc_return(&nr_freq_events) == 1)
9118 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9119 spin_unlock(&nr_freq_lock);
9123 static void account_freq_event(void)
9125 if (tick_nohz_full_enabled())
9126 account_freq_event_nohz();
9128 atomic_inc(&nr_freq_events);
9132 static void account_event(struct perf_event *event)
9139 if (event->attach_state & PERF_ATTACH_TASK)
9141 if (event->attr.mmap || event->attr.mmap_data)
9142 atomic_inc(&nr_mmap_events);
9143 if (event->attr.comm)
9144 atomic_inc(&nr_comm_events);
9145 if (event->attr.task)
9146 atomic_inc(&nr_task_events);
9147 if (event->attr.freq)
9148 account_freq_event();
9149 if (event->attr.context_switch) {
9150 atomic_inc(&nr_switch_events);
9153 if (has_branch_stack(event))
9155 if (is_cgroup_event(event))
9159 if (atomic_inc_not_zero(&perf_sched_count))
9162 mutex_lock(&perf_sched_mutex);
9163 if (!atomic_read(&perf_sched_count)) {
9164 static_branch_enable(&perf_sched_events);
9166 * Guarantee that all CPUs observe they key change and
9167 * call the perf scheduling hooks before proceeding to
9168 * install events that need them.
9170 synchronize_sched();
9173 * Now that we have waited for the sync_sched(), allow further
9174 * increments to by-pass the mutex.
9176 atomic_inc(&perf_sched_count);
9177 mutex_unlock(&perf_sched_mutex);
9181 account_event_cpu(event, event->cpu);
9183 account_pmu_sb_event(event);
9187 * Allocate and initialize a event structure
9189 static struct perf_event *
9190 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9191 struct task_struct *task,
9192 struct perf_event *group_leader,
9193 struct perf_event *parent_event,
9194 perf_overflow_handler_t overflow_handler,
9195 void *context, int cgroup_fd)
9198 struct perf_event *event;
9199 struct hw_perf_event *hwc;
9202 if ((unsigned)cpu >= nr_cpu_ids) {
9203 if (!task || cpu != -1)
9204 return ERR_PTR(-EINVAL);
9207 event = kzalloc(sizeof(*event), GFP_KERNEL);
9209 return ERR_PTR(-ENOMEM);
9212 * Single events are their own group leaders, with an
9213 * empty sibling list:
9216 group_leader = event;
9218 mutex_init(&event->child_mutex);
9219 INIT_LIST_HEAD(&event->child_list);
9221 INIT_LIST_HEAD(&event->group_entry);
9222 INIT_LIST_HEAD(&event->event_entry);
9223 INIT_LIST_HEAD(&event->sibling_list);
9224 INIT_LIST_HEAD(&event->rb_entry);
9225 INIT_LIST_HEAD(&event->active_entry);
9226 INIT_LIST_HEAD(&event->addr_filters.list);
9227 INIT_HLIST_NODE(&event->hlist_entry);
9230 init_waitqueue_head(&event->waitq);
9231 init_irq_work(&event->pending, perf_pending_event);
9233 mutex_init(&event->mmap_mutex);
9234 raw_spin_lock_init(&event->addr_filters.lock);
9236 atomic_long_set(&event->refcount, 1);
9238 event->attr = *attr;
9239 event->group_leader = group_leader;
9243 event->parent = parent_event;
9245 event->ns = get_pid_ns(task_active_pid_ns(current));
9246 event->id = atomic64_inc_return(&perf_event_id);
9248 event->state = PERF_EVENT_STATE_INACTIVE;
9251 event->attach_state = PERF_ATTACH_TASK;
9253 * XXX pmu::event_init needs to know what task to account to
9254 * and we cannot use the ctx information because we need the
9255 * pmu before we get a ctx.
9257 event->hw.target = task;
9260 event->clock = &local_clock;
9262 event->clock = parent_event->clock;
9264 if (!overflow_handler && parent_event) {
9265 overflow_handler = parent_event->overflow_handler;
9266 context = parent_event->overflow_handler_context;
9267 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9268 if (overflow_handler == bpf_overflow_handler) {
9269 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9272 err = PTR_ERR(prog);
9276 event->orig_overflow_handler =
9277 parent_event->orig_overflow_handler;
9282 if (overflow_handler) {
9283 event->overflow_handler = overflow_handler;
9284 event->overflow_handler_context = context;
9285 } else if (is_write_backward(event)){
9286 event->overflow_handler = perf_event_output_backward;
9287 event->overflow_handler_context = NULL;
9289 event->overflow_handler = perf_event_output_forward;
9290 event->overflow_handler_context = NULL;
9293 perf_event__state_init(event);
9298 hwc->sample_period = attr->sample_period;
9299 if (attr->freq && attr->sample_freq)
9300 hwc->sample_period = 1;
9301 hwc->last_period = hwc->sample_period;
9303 local64_set(&hwc->period_left, hwc->sample_period);
9306 * we currently do not support PERF_FORMAT_GROUP on inherited events
9308 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9311 if (!has_branch_stack(event))
9312 event->attr.branch_sample_type = 0;
9314 if (cgroup_fd != -1) {
9315 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9320 pmu = perf_init_event(event);
9323 else if (IS_ERR(pmu)) {
9328 err = exclusive_event_init(event);
9332 if (has_addr_filter(event)) {
9333 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9334 sizeof(unsigned long),
9336 if (!event->addr_filters_offs)
9339 /* force hw sync on the address filters */
9340 event->addr_filters_gen = 1;
9343 if (!event->parent) {
9344 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9345 err = get_callchain_buffers(attr->sample_max_stack);
9347 goto err_addr_filters;
9351 /* symmetric to unaccount_event() in _free_event() */
9352 account_event(event);
9357 kfree(event->addr_filters_offs);
9360 exclusive_event_destroy(event);
9364 event->destroy(event);
9365 module_put(pmu->module);
9367 if (is_cgroup_event(event))
9368 perf_detach_cgroup(event);
9370 put_pid_ns(event->ns);
9373 return ERR_PTR(err);
9376 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9377 struct perf_event_attr *attr)
9382 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9386 * zero the full structure, so that a short copy will be nice.
9388 memset(attr, 0, sizeof(*attr));
9390 ret = get_user(size, &uattr->size);
9394 if (size > PAGE_SIZE) /* silly large */
9397 if (!size) /* abi compat */
9398 size = PERF_ATTR_SIZE_VER0;
9400 if (size < PERF_ATTR_SIZE_VER0)
9404 * If we're handed a bigger struct than we know of,
9405 * ensure all the unknown bits are 0 - i.e. new
9406 * user-space does not rely on any kernel feature
9407 * extensions we dont know about yet.
9409 if (size > sizeof(*attr)) {
9410 unsigned char __user *addr;
9411 unsigned char __user *end;
9414 addr = (void __user *)uattr + sizeof(*attr);
9415 end = (void __user *)uattr + size;
9417 for (; addr < end; addr++) {
9418 ret = get_user(val, addr);
9424 size = sizeof(*attr);
9427 ret = copy_from_user(attr, uattr, size);
9431 if (attr->__reserved_1)
9434 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9437 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9440 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9441 u64 mask = attr->branch_sample_type;
9443 /* only using defined bits */
9444 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9447 /* at least one branch bit must be set */
9448 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9451 /* propagate priv level, when not set for branch */
9452 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9454 /* exclude_kernel checked on syscall entry */
9455 if (!attr->exclude_kernel)
9456 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9458 if (!attr->exclude_user)
9459 mask |= PERF_SAMPLE_BRANCH_USER;
9461 if (!attr->exclude_hv)
9462 mask |= PERF_SAMPLE_BRANCH_HV;
9464 * adjust user setting (for HW filter setup)
9466 attr->branch_sample_type = mask;
9468 /* privileged levels capture (kernel, hv): check permissions */
9469 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9470 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9474 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9475 ret = perf_reg_validate(attr->sample_regs_user);
9480 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9481 if (!arch_perf_have_user_stack_dump())
9485 * We have __u32 type for the size, but so far
9486 * we can only use __u16 as maximum due to the
9487 * __u16 sample size limit.
9489 if (attr->sample_stack_user >= USHRT_MAX)
9491 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9495 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9496 ret = perf_reg_validate(attr->sample_regs_intr);
9501 put_user(sizeof(*attr), &uattr->size);
9507 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9509 struct ring_buffer *rb = NULL;
9515 /* don't allow circular references */
9516 if (event == output_event)
9520 * Don't allow cross-cpu buffers
9522 if (output_event->cpu != event->cpu)
9526 * If its not a per-cpu rb, it must be the same task.
9528 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9532 * Mixing clocks in the same buffer is trouble you don't need.
9534 if (output_event->clock != event->clock)
9538 * Either writing ring buffer from beginning or from end.
9539 * Mixing is not allowed.
9541 if (is_write_backward(output_event) != is_write_backward(event))
9545 * If both events generate aux data, they must be on the same PMU
9547 if (has_aux(event) && has_aux(output_event) &&
9548 event->pmu != output_event->pmu)
9552 mutex_lock(&event->mmap_mutex);
9553 /* Can't redirect output if we've got an active mmap() */
9554 if (atomic_read(&event->mmap_count))
9558 /* get the rb we want to redirect to */
9559 rb = ring_buffer_get(output_event);
9564 ring_buffer_attach(event, rb);
9568 mutex_unlock(&event->mmap_mutex);
9574 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9580 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9583 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9585 bool nmi_safe = false;
9588 case CLOCK_MONOTONIC:
9589 event->clock = &ktime_get_mono_fast_ns;
9593 case CLOCK_MONOTONIC_RAW:
9594 event->clock = &ktime_get_raw_fast_ns;
9598 case CLOCK_REALTIME:
9599 event->clock = &ktime_get_real_ns;
9602 case CLOCK_BOOTTIME:
9603 event->clock = &ktime_get_boot_ns;
9607 event->clock = &ktime_get_tai_ns;
9614 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9621 * Variation on perf_event_ctx_lock_nested(), except we take two context
9624 static struct perf_event_context *
9625 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9626 struct perf_event_context *ctx)
9628 struct perf_event_context *gctx;
9632 gctx = READ_ONCE(group_leader->ctx);
9633 if (!atomic_inc_not_zero(&gctx->refcount)) {
9639 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9641 if (group_leader->ctx != gctx) {
9642 mutex_unlock(&ctx->mutex);
9643 mutex_unlock(&gctx->mutex);
9652 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9654 * @attr_uptr: event_id type attributes for monitoring/sampling
9657 * @group_fd: group leader event fd
9659 SYSCALL_DEFINE5(perf_event_open,
9660 struct perf_event_attr __user *, attr_uptr,
9661 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9663 struct perf_event *group_leader = NULL, *output_event = NULL;
9664 struct perf_event *event, *sibling;
9665 struct perf_event_attr attr;
9666 struct perf_event_context *ctx, *uninitialized_var(gctx);
9667 struct file *event_file = NULL;
9668 struct fd group = {NULL, 0};
9669 struct task_struct *task = NULL;
9674 int f_flags = O_RDWR;
9677 /* for future expandability... */
9678 if (flags & ~PERF_FLAG_ALL)
9681 err = perf_copy_attr(attr_uptr, &attr);
9685 if (!attr.exclude_kernel) {
9686 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9691 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9694 if (attr.sample_period & (1ULL << 63))
9698 if (!attr.sample_max_stack)
9699 attr.sample_max_stack = sysctl_perf_event_max_stack;
9702 * In cgroup mode, the pid argument is used to pass the fd
9703 * opened to the cgroup directory in cgroupfs. The cpu argument
9704 * designates the cpu on which to monitor threads from that
9707 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9710 if (flags & PERF_FLAG_FD_CLOEXEC)
9711 f_flags |= O_CLOEXEC;
9713 event_fd = get_unused_fd_flags(f_flags);
9717 if (group_fd != -1) {
9718 err = perf_fget_light(group_fd, &group);
9721 group_leader = group.file->private_data;
9722 if (flags & PERF_FLAG_FD_OUTPUT)
9723 output_event = group_leader;
9724 if (flags & PERF_FLAG_FD_NO_GROUP)
9725 group_leader = NULL;
9728 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9729 task = find_lively_task_by_vpid(pid);
9731 err = PTR_ERR(task);
9736 if (task && group_leader &&
9737 group_leader->attr.inherit != attr.inherit) {
9745 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9750 * Reuse ptrace permission checks for now.
9752 * We must hold cred_guard_mutex across this and any potential
9753 * perf_install_in_context() call for this new event to
9754 * serialize against exec() altering our credentials (and the
9755 * perf_event_exit_task() that could imply).
9758 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9762 if (flags & PERF_FLAG_PID_CGROUP)
9765 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9766 NULL, NULL, cgroup_fd);
9767 if (IS_ERR(event)) {
9768 err = PTR_ERR(event);
9772 if (is_sampling_event(event)) {
9773 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9780 * Special case software events and allow them to be part of
9781 * any hardware group.
9785 if (attr.use_clockid) {
9786 err = perf_event_set_clock(event, attr.clockid);
9791 if (pmu->task_ctx_nr == perf_sw_context)
9792 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9795 (is_software_event(event) != is_software_event(group_leader))) {
9796 if (is_software_event(event)) {
9798 * If event and group_leader are not both a software
9799 * event, and event is, then group leader is not.
9801 * Allow the addition of software events to !software
9802 * groups, this is safe because software events never
9805 pmu = group_leader->pmu;
9806 } else if (is_software_event(group_leader) &&
9807 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9809 * In case the group is a pure software group, and we
9810 * try to add a hardware event, move the whole group to
9811 * the hardware context.
9818 * Get the target context (task or percpu):
9820 ctx = find_get_context(pmu, task, event);
9826 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9832 * Look up the group leader (we will attach this event to it):
9838 * Do not allow a recursive hierarchy (this new sibling
9839 * becoming part of another group-sibling):
9841 if (group_leader->group_leader != group_leader)
9844 /* All events in a group should have the same clock */
9845 if (group_leader->clock != event->clock)
9849 * Do not allow to attach to a group in a different
9850 * task or CPU context:
9854 * Make sure we're both on the same task, or both
9857 if (group_leader->ctx->task != ctx->task)
9861 * Make sure we're both events for the same CPU;
9862 * grouping events for different CPUs is broken; since
9863 * you can never concurrently schedule them anyhow.
9865 if (group_leader->cpu != event->cpu)
9868 if (group_leader->ctx != ctx)
9873 * Only a group leader can be exclusive or pinned
9875 if (attr.exclusive || attr.pinned)
9880 err = perf_event_set_output(event, output_event);
9885 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9887 if (IS_ERR(event_file)) {
9888 err = PTR_ERR(event_file);
9894 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
9896 if (gctx->task == TASK_TOMBSTONE) {
9902 * Check if we raced against another sys_perf_event_open() call
9903 * moving the software group underneath us.
9905 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9907 * If someone moved the group out from under us, check
9908 * if this new event wound up on the same ctx, if so
9909 * its the regular !move_group case, otherwise fail.
9915 perf_event_ctx_unlock(group_leader, gctx);
9920 mutex_lock(&ctx->mutex);
9923 if (ctx->task == TASK_TOMBSTONE) {
9928 if (!perf_event_validate_size(event)) {
9934 * Must be under the same ctx::mutex as perf_install_in_context(),
9935 * because we need to serialize with concurrent event creation.
9937 if (!exclusive_event_installable(event, ctx)) {
9938 /* exclusive and group stuff are assumed mutually exclusive */
9939 WARN_ON_ONCE(move_group);
9945 WARN_ON_ONCE(ctx->parent_ctx);
9948 * This is the point on no return; we cannot fail hereafter. This is
9949 * where we start modifying current state.
9954 * See perf_event_ctx_lock() for comments on the details
9955 * of swizzling perf_event::ctx.
9957 perf_remove_from_context(group_leader, 0);
9959 list_for_each_entry(sibling, &group_leader->sibling_list,
9961 perf_remove_from_context(sibling, 0);
9966 * Wait for everybody to stop referencing the events through
9967 * the old lists, before installing it on new lists.
9972 * Install the group siblings before the group leader.
9974 * Because a group leader will try and install the entire group
9975 * (through the sibling list, which is still in-tact), we can
9976 * end up with siblings installed in the wrong context.
9978 * By installing siblings first we NO-OP because they're not
9979 * reachable through the group lists.
9981 list_for_each_entry(sibling, &group_leader->sibling_list,
9983 perf_event__state_init(sibling);
9984 perf_install_in_context(ctx, sibling, sibling->cpu);
9989 * Removing from the context ends up with disabled
9990 * event. What we want here is event in the initial
9991 * startup state, ready to be add into new context.
9993 perf_event__state_init(group_leader);
9994 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9998 * Now that all events are installed in @ctx, nothing
9999 * references @gctx anymore, so drop the last reference we have
10006 * Precalculate sample_data sizes; do while holding ctx::mutex such
10007 * that we're serialized against further additions and before
10008 * perf_install_in_context() which is the point the event is active and
10009 * can use these values.
10011 perf_event__header_size(event);
10012 perf_event__id_header_size(event);
10014 event->owner = current;
10016 perf_install_in_context(ctx, event, event->cpu);
10017 perf_unpin_context(ctx);
10020 perf_event_ctx_unlock(group_leader, gctx);
10021 mutex_unlock(&ctx->mutex);
10024 mutex_unlock(&task->signal->cred_guard_mutex);
10025 put_task_struct(task);
10030 mutex_lock(¤t->perf_event_mutex);
10031 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10032 mutex_unlock(¤t->perf_event_mutex);
10035 * Drop the reference on the group_event after placing the
10036 * new event on the sibling_list. This ensures destruction
10037 * of the group leader will find the pointer to itself in
10038 * perf_group_detach().
10041 fd_install(event_fd, event_file);
10046 perf_event_ctx_unlock(group_leader, gctx);
10047 mutex_unlock(&ctx->mutex);
10051 perf_unpin_context(ctx);
10055 * If event_file is set, the fput() above will have called ->release()
10056 * and that will take care of freeing the event.
10062 mutex_unlock(&task->signal->cred_guard_mutex);
10067 put_task_struct(task);
10071 put_unused_fd(event_fd);
10076 * perf_event_create_kernel_counter
10078 * @attr: attributes of the counter to create
10079 * @cpu: cpu in which the counter is bound
10080 * @task: task to profile (NULL for percpu)
10082 struct perf_event *
10083 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10084 struct task_struct *task,
10085 perf_overflow_handler_t overflow_handler,
10088 struct perf_event_context *ctx;
10089 struct perf_event *event;
10093 * Get the target context (task or percpu):
10096 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10097 overflow_handler, context, -1);
10098 if (IS_ERR(event)) {
10099 err = PTR_ERR(event);
10103 /* Mark owner so we could distinguish it from user events. */
10104 event->owner = TASK_TOMBSTONE;
10106 ctx = find_get_context(event->pmu, task, event);
10108 err = PTR_ERR(ctx);
10112 WARN_ON_ONCE(ctx->parent_ctx);
10113 mutex_lock(&ctx->mutex);
10114 if (ctx->task == TASK_TOMBSTONE) {
10119 if (!exclusive_event_installable(event, ctx)) {
10124 perf_install_in_context(ctx, event, cpu);
10125 perf_unpin_context(ctx);
10126 mutex_unlock(&ctx->mutex);
10131 mutex_unlock(&ctx->mutex);
10132 perf_unpin_context(ctx);
10137 return ERR_PTR(err);
10139 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10141 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10143 struct perf_event_context *src_ctx;
10144 struct perf_event_context *dst_ctx;
10145 struct perf_event *event, *tmp;
10148 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10149 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10152 * See perf_event_ctx_lock() for comments on the details
10153 * of swizzling perf_event::ctx.
10155 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10156 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10158 perf_remove_from_context(event, 0);
10159 unaccount_event_cpu(event, src_cpu);
10161 list_add(&event->migrate_entry, &events);
10165 * Wait for the events to quiesce before re-instating them.
10170 * Re-instate events in 2 passes.
10172 * Skip over group leaders and only install siblings on this first
10173 * pass, siblings will not get enabled without a leader, however a
10174 * leader will enable its siblings, even if those are still on the old
10177 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10178 if (event->group_leader == event)
10181 list_del(&event->migrate_entry);
10182 if (event->state >= PERF_EVENT_STATE_OFF)
10183 event->state = PERF_EVENT_STATE_INACTIVE;
10184 account_event_cpu(event, dst_cpu);
10185 perf_install_in_context(dst_ctx, event, dst_cpu);
10190 * Once all the siblings are setup properly, install the group leaders
10193 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10194 list_del(&event->migrate_entry);
10195 if (event->state >= PERF_EVENT_STATE_OFF)
10196 event->state = PERF_EVENT_STATE_INACTIVE;
10197 account_event_cpu(event, dst_cpu);
10198 perf_install_in_context(dst_ctx, event, dst_cpu);
10201 mutex_unlock(&dst_ctx->mutex);
10202 mutex_unlock(&src_ctx->mutex);
10204 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10206 static void sync_child_event(struct perf_event *child_event,
10207 struct task_struct *child)
10209 struct perf_event *parent_event = child_event->parent;
10212 if (child_event->attr.inherit_stat)
10213 perf_event_read_event(child_event, child);
10215 child_val = perf_event_count(child_event);
10218 * Add back the child's count to the parent's count:
10220 atomic64_add(child_val, &parent_event->child_count);
10221 atomic64_add(child_event->total_time_enabled,
10222 &parent_event->child_total_time_enabled);
10223 atomic64_add(child_event->total_time_running,
10224 &parent_event->child_total_time_running);
10228 perf_event_exit_event(struct perf_event *child_event,
10229 struct perf_event_context *child_ctx,
10230 struct task_struct *child)
10232 struct perf_event *parent_event = child_event->parent;
10235 * Do not destroy the 'original' grouping; because of the context
10236 * switch optimization the original events could've ended up in a
10237 * random child task.
10239 * If we were to destroy the original group, all group related
10240 * operations would cease to function properly after this random
10243 * Do destroy all inherited groups, we don't care about those
10244 * and being thorough is better.
10246 raw_spin_lock_irq(&child_ctx->lock);
10247 WARN_ON_ONCE(child_ctx->is_active);
10250 perf_group_detach(child_event);
10251 list_del_event(child_event, child_ctx);
10252 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10253 raw_spin_unlock_irq(&child_ctx->lock);
10256 * Parent events are governed by their filedesc, retain them.
10258 if (!parent_event) {
10259 perf_event_wakeup(child_event);
10263 * Child events can be cleaned up.
10266 sync_child_event(child_event, child);
10269 * Remove this event from the parent's list
10271 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10272 mutex_lock(&parent_event->child_mutex);
10273 list_del_init(&child_event->child_list);
10274 mutex_unlock(&parent_event->child_mutex);
10277 * Kick perf_poll() for is_event_hup().
10279 perf_event_wakeup(parent_event);
10280 free_event(child_event);
10281 put_event(parent_event);
10284 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10286 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10287 struct perf_event *child_event, *next;
10289 WARN_ON_ONCE(child != current);
10291 child_ctx = perf_pin_task_context(child, ctxn);
10296 * In order to reduce the amount of tricky in ctx tear-down, we hold
10297 * ctx::mutex over the entire thing. This serializes against almost
10298 * everything that wants to access the ctx.
10300 * The exception is sys_perf_event_open() /
10301 * perf_event_create_kernel_count() which does find_get_context()
10302 * without ctx::mutex (it cannot because of the move_group double mutex
10303 * lock thing). See the comments in perf_install_in_context().
10305 mutex_lock(&child_ctx->mutex);
10308 * In a single ctx::lock section, de-schedule the events and detach the
10309 * context from the task such that we cannot ever get it scheduled back
10312 raw_spin_lock_irq(&child_ctx->lock);
10313 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10316 * Now that the context is inactive, destroy the task <-> ctx relation
10317 * and mark the context dead.
10319 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10320 put_ctx(child_ctx); /* cannot be last */
10321 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10322 put_task_struct(current); /* cannot be last */
10324 clone_ctx = unclone_ctx(child_ctx);
10325 raw_spin_unlock_irq(&child_ctx->lock);
10328 put_ctx(clone_ctx);
10331 * Report the task dead after unscheduling the events so that we
10332 * won't get any samples after PERF_RECORD_EXIT. We can however still
10333 * get a few PERF_RECORD_READ events.
10335 perf_event_task(child, child_ctx, 0);
10337 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10338 perf_event_exit_event(child_event, child_ctx, child);
10340 mutex_unlock(&child_ctx->mutex);
10342 put_ctx(child_ctx);
10346 * When a child task exits, feed back event values to parent events.
10348 * Can be called with cred_guard_mutex held when called from
10349 * install_exec_creds().
10351 void perf_event_exit_task(struct task_struct *child)
10353 struct perf_event *event, *tmp;
10356 mutex_lock(&child->perf_event_mutex);
10357 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10359 list_del_init(&event->owner_entry);
10362 * Ensure the list deletion is visible before we clear
10363 * the owner, closes a race against perf_release() where
10364 * we need to serialize on the owner->perf_event_mutex.
10366 smp_store_release(&event->owner, NULL);
10368 mutex_unlock(&child->perf_event_mutex);
10370 for_each_task_context_nr(ctxn)
10371 perf_event_exit_task_context(child, ctxn);
10374 * The perf_event_exit_task_context calls perf_event_task
10375 * with child's task_ctx, which generates EXIT events for
10376 * child contexts and sets child->perf_event_ctxp[] to NULL.
10377 * At this point we need to send EXIT events to cpu contexts.
10379 perf_event_task(child, NULL, 0);
10382 static void perf_free_event(struct perf_event *event,
10383 struct perf_event_context *ctx)
10385 struct perf_event *parent = event->parent;
10387 if (WARN_ON_ONCE(!parent))
10390 mutex_lock(&parent->child_mutex);
10391 list_del_init(&event->child_list);
10392 mutex_unlock(&parent->child_mutex);
10396 raw_spin_lock_irq(&ctx->lock);
10397 perf_group_detach(event);
10398 list_del_event(event, ctx);
10399 raw_spin_unlock_irq(&ctx->lock);
10404 * Free an unexposed, unused context as created by inheritance by
10405 * perf_event_init_task below, used by fork() in case of fail.
10407 * Not all locks are strictly required, but take them anyway to be nice and
10408 * help out with the lockdep assertions.
10410 void perf_event_free_task(struct task_struct *task)
10412 struct perf_event_context *ctx;
10413 struct perf_event *event, *tmp;
10416 for_each_task_context_nr(ctxn) {
10417 ctx = task->perf_event_ctxp[ctxn];
10421 mutex_lock(&ctx->mutex);
10423 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
10425 perf_free_event(event, ctx);
10427 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
10429 perf_free_event(event, ctx);
10431 if (!list_empty(&ctx->pinned_groups) ||
10432 !list_empty(&ctx->flexible_groups))
10435 mutex_unlock(&ctx->mutex);
10441 void perf_event_delayed_put(struct task_struct *task)
10445 for_each_task_context_nr(ctxn)
10446 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10449 struct file *perf_event_get(unsigned int fd)
10453 file = fget_raw(fd);
10455 return ERR_PTR(-EBADF);
10457 if (file->f_op != &perf_fops) {
10459 return ERR_PTR(-EBADF);
10465 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10468 return ERR_PTR(-EINVAL);
10470 return &event->attr;
10474 * inherit a event from parent task to child task:
10476 static struct perf_event *
10477 inherit_event(struct perf_event *parent_event,
10478 struct task_struct *parent,
10479 struct perf_event_context *parent_ctx,
10480 struct task_struct *child,
10481 struct perf_event *group_leader,
10482 struct perf_event_context *child_ctx)
10484 enum perf_event_active_state parent_state = parent_event->state;
10485 struct perf_event *child_event;
10486 unsigned long flags;
10489 * Instead of creating recursive hierarchies of events,
10490 * we link inherited events back to the original parent,
10491 * which has a filp for sure, which we use as the reference
10494 if (parent_event->parent)
10495 parent_event = parent_event->parent;
10497 child_event = perf_event_alloc(&parent_event->attr,
10500 group_leader, parent_event,
10502 if (IS_ERR(child_event))
10503 return child_event;
10506 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10507 * must be under the same lock in order to serialize against
10508 * perf_event_release_kernel(), such that either we must observe
10509 * is_orphaned_event() or they will observe us on the child_list.
10511 mutex_lock(&parent_event->child_mutex);
10512 if (is_orphaned_event(parent_event) ||
10513 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10514 mutex_unlock(&parent_event->child_mutex);
10515 free_event(child_event);
10519 get_ctx(child_ctx);
10522 * Make the child state follow the state of the parent event,
10523 * not its attr.disabled bit. We hold the parent's mutex,
10524 * so we won't race with perf_event_{en, dis}able_family.
10526 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10527 child_event->state = PERF_EVENT_STATE_INACTIVE;
10529 child_event->state = PERF_EVENT_STATE_OFF;
10531 if (parent_event->attr.freq) {
10532 u64 sample_period = parent_event->hw.sample_period;
10533 struct hw_perf_event *hwc = &child_event->hw;
10535 hwc->sample_period = sample_period;
10536 hwc->last_period = sample_period;
10538 local64_set(&hwc->period_left, sample_period);
10541 child_event->ctx = child_ctx;
10542 child_event->overflow_handler = parent_event->overflow_handler;
10543 child_event->overflow_handler_context
10544 = parent_event->overflow_handler_context;
10547 * Precalculate sample_data sizes
10549 perf_event__header_size(child_event);
10550 perf_event__id_header_size(child_event);
10553 * Link it up in the child's context:
10555 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10556 add_event_to_ctx(child_event, child_ctx);
10557 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10560 * Link this into the parent event's child list
10562 list_add_tail(&child_event->child_list, &parent_event->child_list);
10563 mutex_unlock(&parent_event->child_mutex);
10565 return child_event;
10568 static int inherit_group(struct perf_event *parent_event,
10569 struct task_struct *parent,
10570 struct perf_event_context *parent_ctx,
10571 struct task_struct *child,
10572 struct perf_event_context *child_ctx)
10574 struct perf_event *leader;
10575 struct perf_event *sub;
10576 struct perf_event *child_ctr;
10578 leader = inherit_event(parent_event, parent, parent_ctx,
10579 child, NULL, child_ctx);
10580 if (IS_ERR(leader))
10581 return PTR_ERR(leader);
10582 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10583 child_ctr = inherit_event(sub, parent, parent_ctx,
10584 child, leader, child_ctx);
10585 if (IS_ERR(child_ctr))
10586 return PTR_ERR(child_ctr);
10592 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10593 struct perf_event_context *parent_ctx,
10594 struct task_struct *child, int ctxn,
10595 int *inherited_all)
10598 struct perf_event_context *child_ctx;
10600 if (!event->attr.inherit) {
10601 *inherited_all = 0;
10605 child_ctx = child->perf_event_ctxp[ctxn];
10608 * This is executed from the parent task context, so
10609 * inherit events that have been marked for cloning.
10610 * First allocate and initialize a context for the
10614 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10618 child->perf_event_ctxp[ctxn] = child_ctx;
10621 ret = inherit_group(event, parent, parent_ctx,
10625 *inherited_all = 0;
10631 * Initialize the perf_event context in task_struct
10633 static int perf_event_init_context(struct task_struct *child, int ctxn)
10635 struct perf_event_context *child_ctx, *parent_ctx;
10636 struct perf_event_context *cloned_ctx;
10637 struct perf_event *event;
10638 struct task_struct *parent = current;
10639 int inherited_all = 1;
10640 unsigned long flags;
10643 if (likely(!parent->perf_event_ctxp[ctxn]))
10647 * If the parent's context is a clone, pin it so it won't get
10648 * swapped under us.
10650 parent_ctx = perf_pin_task_context(parent, ctxn);
10655 * No need to check if parent_ctx != NULL here; since we saw
10656 * it non-NULL earlier, the only reason for it to become NULL
10657 * is if we exit, and since we're currently in the middle of
10658 * a fork we can't be exiting at the same time.
10662 * Lock the parent list. No need to lock the child - not PID
10663 * hashed yet and not running, so nobody can access it.
10665 mutex_lock(&parent_ctx->mutex);
10668 * We dont have to disable NMIs - we are only looking at
10669 * the list, not manipulating it:
10671 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10672 ret = inherit_task_group(event, parent, parent_ctx,
10673 child, ctxn, &inherited_all);
10679 * We can't hold ctx->lock when iterating the ->flexible_group list due
10680 * to allocations, but we need to prevent rotation because
10681 * rotate_ctx() will change the list from interrupt context.
10683 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10684 parent_ctx->rotate_disable = 1;
10685 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10687 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10688 ret = inherit_task_group(event, parent, parent_ctx,
10689 child, ctxn, &inherited_all);
10694 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10695 parent_ctx->rotate_disable = 0;
10697 child_ctx = child->perf_event_ctxp[ctxn];
10699 if (child_ctx && inherited_all) {
10701 * Mark the child context as a clone of the parent
10702 * context, or of whatever the parent is a clone of.
10704 * Note that if the parent is a clone, the holding of
10705 * parent_ctx->lock avoids it from being uncloned.
10707 cloned_ctx = parent_ctx->parent_ctx;
10709 child_ctx->parent_ctx = cloned_ctx;
10710 child_ctx->parent_gen = parent_ctx->parent_gen;
10712 child_ctx->parent_ctx = parent_ctx;
10713 child_ctx->parent_gen = parent_ctx->generation;
10715 get_ctx(child_ctx->parent_ctx);
10718 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10719 mutex_unlock(&parent_ctx->mutex);
10721 perf_unpin_context(parent_ctx);
10722 put_ctx(parent_ctx);
10728 * Initialize the perf_event context in task_struct
10730 int perf_event_init_task(struct task_struct *child)
10734 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10735 mutex_init(&child->perf_event_mutex);
10736 INIT_LIST_HEAD(&child->perf_event_list);
10738 for_each_task_context_nr(ctxn) {
10739 ret = perf_event_init_context(child, ctxn);
10741 perf_event_free_task(child);
10749 static void __init perf_event_init_all_cpus(void)
10751 struct swevent_htable *swhash;
10754 for_each_possible_cpu(cpu) {
10755 swhash = &per_cpu(swevent_htable, cpu);
10756 mutex_init(&swhash->hlist_mutex);
10757 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10759 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10760 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10762 #ifdef CONFIG_CGROUP_PERF
10763 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10765 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10769 int perf_event_init_cpu(unsigned int cpu)
10771 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10773 mutex_lock(&swhash->hlist_mutex);
10774 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10775 struct swevent_hlist *hlist;
10777 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10779 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10781 mutex_unlock(&swhash->hlist_mutex);
10785 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10786 static void __perf_event_exit_context(void *__info)
10788 struct perf_event_context *ctx = __info;
10789 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10790 struct perf_event *event;
10792 raw_spin_lock(&ctx->lock);
10793 list_for_each_entry(event, &ctx->event_list, event_entry)
10794 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10795 raw_spin_unlock(&ctx->lock);
10798 static void perf_event_exit_cpu_context(int cpu)
10800 struct perf_event_context *ctx;
10804 idx = srcu_read_lock(&pmus_srcu);
10805 list_for_each_entry_rcu(pmu, &pmus, entry) {
10806 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10808 mutex_lock(&ctx->mutex);
10809 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10810 mutex_unlock(&ctx->mutex);
10812 srcu_read_unlock(&pmus_srcu, idx);
10816 static void perf_event_exit_cpu_context(int cpu) { }
10820 int perf_event_exit_cpu(unsigned int cpu)
10822 perf_event_exit_cpu_context(cpu);
10827 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10831 for_each_online_cpu(cpu)
10832 perf_event_exit_cpu(cpu);
10838 * Run the perf reboot notifier at the very last possible moment so that
10839 * the generic watchdog code runs as long as possible.
10841 static struct notifier_block perf_reboot_notifier = {
10842 .notifier_call = perf_reboot,
10843 .priority = INT_MIN,
10846 void __init perf_event_init(void)
10850 idr_init(&pmu_idr);
10852 perf_event_init_all_cpus();
10853 init_srcu_struct(&pmus_srcu);
10854 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10855 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10856 perf_pmu_register(&perf_task_clock, NULL, -1);
10857 perf_tp_register();
10858 perf_event_init_cpu(smp_processor_id());
10859 register_reboot_notifier(&perf_reboot_notifier);
10861 ret = init_hw_breakpoint();
10862 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10865 * Build time assertion that we keep the data_head at the intended
10866 * location. IOW, validation we got the __reserved[] size right.
10868 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10872 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10875 struct perf_pmu_events_attr *pmu_attr =
10876 container_of(attr, struct perf_pmu_events_attr, attr);
10878 if (pmu_attr->event_str)
10879 return sprintf(page, "%s\n", pmu_attr->event_str);
10883 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10885 static int __init perf_event_sysfs_init(void)
10890 mutex_lock(&pmus_lock);
10892 ret = bus_register(&pmu_bus);
10896 list_for_each_entry(pmu, &pmus, entry) {
10897 if (!pmu->name || pmu->type < 0)
10900 ret = pmu_dev_alloc(pmu);
10901 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10903 pmu_bus_running = 1;
10907 mutex_unlock(&pmus_lock);
10911 device_initcall(perf_event_sysfs_init);
10913 #ifdef CONFIG_CGROUP_PERF
10914 static struct cgroup_subsys_state *
10915 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10917 struct perf_cgroup *jc;
10919 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10921 return ERR_PTR(-ENOMEM);
10923 jc->info = alloc_percpu(struct perf_cgroup_info);
10926 return ERR_PTR(-ENOMEM);
10932 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10934 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10936 free_percpu(jc->info);
10940 static int __perf_cgroup_move(void *info)
10942 struct task_struct *task = info;
10944 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10949 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10951 struct task_struct *task;
10952 struct cgroup_subsys_state *css;
10954 cgroup_taskset_for_each(task, css, tset)
10955 task_function_call(task, __perf_cgroup_move, task);
10958 struct cgroup_subsys perf_event_cgrp_subsys = {
10959 .css_alloc = perf_cgroup_css_alloc,
10960 .css_free = perf_cgroup_css_free,
10961 .attach = perf_cgroup_attach,
10963 #endif /* CONFIG_CGROUP_PERF */