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>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly. This will
98 * retry due to any failures in smp_call_function_single(), such as if the
99 * task_cpu() goes offline concurrently.
101 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function,
130 * cpu_function_call - call a function on the cpu
131 * @func: the function to be called
132 * @info: the function call argument
134 * Calls the function @func on the remote cpu.
136 * returns: @func return value or -ENXIO when the cpu is offline
138 static int cpu_function_call(int cpu, remote_function_f func, void *info)
140 struct remote_function_call data = {
144 .ret = -ENXIO, /* No such CPU */
147 smp_call_function_single(cpu, remote_function, &data, 1);
152 static inline struct perf_cpu_context *
153 __get_cpu_context(struct perf_event_context *ctx)
155 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
158 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
159 struct perf_event_context *ctx)
161 raw_spin_lock(&cpuctx->ctx.lock);
163 raw_spin_lock(&ctx->lock);
166 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
167 struct perf_event_context *ctx)
170 raw_spin_unlock(&ctx->lock);
171 raw_spin_unlock(&cpuctx->ctx.lock);
174 #define TASK_TOMBSTONE ((void *)-1L)
176 static bool is_kernel_event(struct perf_event *event)
178 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
182 * On task ctx scheduling...
184 * When !ctx->nr_events a task context will not be scheduled. This means
185 * we can disable the scheduler hooks (for performance) without leaving
186 * pending task ctx state.
188 * This however results in two special cases:
190 * - removing the last event from a task ctx; this is relatively straight
191 * forward and is done in __perf_remove_from_context.
193 * - adding the first event to a task ctx; this is tricky because we cannot
194 * rely on ctx->is_active and therefore cannot use event_function_call().
195 * See perf_install_in_context().
197 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
200 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
201 struct perf_event_context *, void *);
203 struct event_function_struct {
204 struct perf_event *event;
209 static int event_function(void *info)
211 struct event_function_struct *efs = info;
212 struct perf_event *event = efs->event;
213 struct perf_event_context *ctx = event->ctx;
214 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
215 struct perf_event_context *task_ctx = cpuctx->task_ctx;
218 lockdep_assert_irqs_disabled();
220 perf_ctx_lock(cpuctx, task_ctx);
222 * Since we do the IPI call without holding ctx->lock things can have
223 * changed, double check we hit the task we set out to hit.
226 if (ctx->task != current) {
232 * We only use event_function_call() on established contexts,
233 * and event_function() is only ever called when active (or
234 * rather, we'll have bailed in task_function_call() or the
235 * above ctx->task != current test), therefore we must have
236 * ctx->is_active here.
238 WARN_ON_ONCE(!ctx->is_active);
240 * And since we have ctx->is_active, cpuctx->task_ctx must
243 WARN_ON_ONCE(task_ctx != ctx);
245 WARN_ON_ONCE(&cpuctx->ctx != ctx);
248 efs->func(event, cpuctx, ctx, efs->data);
250 perf_ctx_unlock(cpuctx, task_ctx);
255 static void event_function_call(struct perf_event *event, event_f func, void *data)
257 struct perf_event_context *ctx = event->ctx;
258 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
259 struct event_function_struct efs = {
265 if (!event->parent) {
267 * If this is a !child event, we must hold ctx::mutex to
268 * stabilize the the event->ctx relation. See
269 * perf_event_ctx_lock().
271 lockdep_assert_held(&ctx->mutex);
275 cpu_function_call(event->cpu, event_function, &efs);
279 if (task == TASK_TOMBSTONE)
283 if (!task_function_call(task, event_function, &efs))
286 raw_spin_lock_irq(&ctx->lock);
288 * Reload the task pointer, it might have been changed by
289 * a concurrent perf_event_context_sched_out().
292 if (task == TASK_TOMBSTONE) {
293 raw_spin_unlock_irq(&ctx->lock);
296 if (ctx->is_active) {
297 raw_spin_unlock_irq(&ctx->lock);
300 func(event, NULL, ctx, data);
301 raw_spin_unlock_irq(&ctx->lock);
305 * Similar to event_function_call() + event_function(), but hard assumes IRQs
306 * are already disabled and we're on the right CPU.
308 static void event_function_local(struct perf_event *event, event_f func, void *data)
310 struct perf_event_context *ctx = event->ctx;
311 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
312 struct task_struct *task = READ_ONCE(ctx->task);
313 struct perf_event_context *task_ctx = NULL;
315 lockdep_assert_irqs_disabled();
318 if (task == TASK_TOMBSTONE)
324 perf_ctx_lock(cpuctx, task_ctx);
327 if (task == TASK_TOMBSTONE)
332 * We must be either inactive or active and the right task,
333 * otherwise we're screwed, since we cannot IPI to somewhere
336 if (ctx->is_active) {
337 if (WARN_ON_ONCE(task != current))
340 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
344 WARN_ON_ONCE(&cpuctx->ctx != ctx);
347 func(event, cpuctx, ctx, data);
349 perf_ctx_unlock(cpuctx, task_ctx);
352 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
353 PERF_FLAG_FD_OUTPUT |\
354 PERF_FLAG_PID_CGROUP |\
355 PERF_FLAG_FD_CLOEXEC)
358 * branch priv levels that need permission checks
360 #define PERF_SAMPLE_BRANCH_PERM_PLM \
361 (PERF_SAMPLE_BRANCH_KERNEL |\
362 PERF_SAMPLE_BRANCH_HV)
365 EVENT_FLEXIBLE = 0x1,
368 /* see ctx_resched() for details */
370 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
374 * perf_sched_events : >0 events exist
375 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
378 static void perf_sched_delayed(struct work_struct *work);
379 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
380 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
381 static DEFINE_MUTEX(perf_sched_mutex);
382 static atomic_t perf_sched_count;
384 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
385 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
386 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
388 static atomic_t nr_mmap_events __read_mostly;
389 static atomic_t nr_comm_events __read_mostly;
390 static atomic_t nr_namespaces_events __read_mostly;
391 static atomic_t nr_task_events __read_mostly;
392 static atomic_t nr_freq_events __read_mostly;
393 static atomic_t nr_switch_events __read_mostly;
395 static LIST_HEAD(pmus);
396 static DEFINE_MUTEX(pmus_lock);
397 static struct srcu_struct pmus_srcu;
398 static cpumask_var_t perf_online_mask;
401 * perf event paranoia level:
402 * -1 - not paranoid at all
403 * 0 - disallow raw tracepoint access for unpriv
404 * 1 - disallow cpu events for unpriv
405 * 2 - disallow kernel profiling for unpriv
407 int sysctl_perf_event_paranoid __read_mostly = 2;
409 /* Minimum for 512 kiB + 1 user control page */
410 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
413 * max perf event sample rate
415 #define DEFAULT_MAX_SAMPLE_RATE 100000
416 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
417 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
419 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
421 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
422 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
424 static int perf_sample_allowed_ns __read_mostly =
425 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
427 static void update_perf_cpu_limits(void)
429 u64 tmp = perf_sample_period_ns;
431 tmp *= sysctl_perf_cpu_time_max_percent;
432 tmp = div_u64(tmp, 100);
436 WRITE_ONCE(perf_sample_allowed_ns, tmp);
439 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
441 int perf_proc_update_handler(struct ctl_table *table, int write,
442 void __user *buffer, size_t *lenp,
446 int perf_cpu = sysctl_perf_cpu_time_max_percent;
448 * If throttling is disabled don't allow the write:
450 if (write && (perf_cpu == 100 || perf_cpu == 0))
453 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
457 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
458 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
459 update_perf_cpu_limits();
464 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
466 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
467 void __user *buffer, size_t *lenp,
470 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
475 if (sysctl_perf_cpu_time_max_percent == 100 ||
476 sysctl_perf_cpu_time_max_percent == 0) {
478 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
479 WRITE_ONCE(perf_sample_allowed_ns, 0);
481 update_perf_cpu_limits();
488 * perf samples are done in some very critical code paths (NMIs).
489 * If they take too much CPU time, the system can lock up and not
490 * get any real work done. This will drop the sample rate when
491 * we detect that events are taking too long.
493 #define NR_ACCUMULATED_SAMPLES 128
494 static DEFINE_PER_CPU(u64, running_sample_length);
496 static u64 __report_avg;
497 static u64 __report_allowed;
499 static void perf_duration_warn(struct irq_work *w)
501 printk_ratelimited(KERN_INFO
502 "perf: interrupt took too long (%lld > %lld), lowering "
503 "kernel.perf_event_max_sample_rate to %d\n",
504 __report_avg, __report_allowed,
505 sysctl_perf_event_sample_rate);
508 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
510 void perf_sample_event_took(u64 sample_len_ns)
512 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
520 /* Decay the counter by 1 average sample. */
521 running_len = __this_cpu_read(running_sample_length);
522 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
523 running_len += sample_len_ns;
524 __this_cpu_write(running_sample_length, running_len);
527 * Note: this will be biased artifically low until we have
528 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
529 * from having to maintain a count.
531 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
532 if (avg_len <= max_len)
535 __report_avg = avg_len;
536 __report_allowed = max_len;
539 * Compute a throttle threshold 25% below the current duration.
541 avg_len += avg_len / 4;
542 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
548 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
549 WRITE_ONCE(max_samples_per_tick, max);
551 sysctl_perf_event_sample_rate = max * HZ;
552 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
554 if (!irq_work_queue(&perf_duration_work)) {
555 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
556 "kernel.perf_event_max_sample_rate to %d\n",
557 __report_avg, __report_allowed,
558 sysctl_perf_event_sample_rate);
562 static atomic64_t perf_event_id;
564 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
565 enum event_type_t event_type);
567 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
568 enum event_type_t event_type,
569 struct task_struct *task);
571 static void update_context_time(struct perf_event_context *ctx);
572 static u64 perf_event_time(struct perf_event *event);
574 void __weak perf_event_print_debug(void) { }
576 extern __weak const char *perf_pmu_name(void)
581 static inline u64 perf_clock(void)
583 return local_clock();
586 static inline u64 perf_event_clock(struct perf_event *event)
588 return event->clock();
592 * State based event timekeeping...
594 * The basic idea is to use event->state to determine which (if any) time
595 * fields to increment with the current delta. This means we only need to
596 * update timestamps when we change state or when they are explicitly requested
599 * Event groups make things a little more complicated, but not terribly so. The
600 * rules for a group are that if the group leader is OFF the entire group is
601 * OFF, irrespecive of what the group member states are. This results in
602 * __perf_effective_state().
604 * A futher ramification is that when a group leader flips between OFF and
605 * !OFF, we need to update all group member times.
608 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
609 * need to make sure the relevant context time is updated before we try and
610 * update our timestamps.
613 static __always_inline enum perf_event_state
614 __perf_effective_state(struct perf_event *event)
616 struct perf_event *leader = event->group_leader;
618 if (leader->state <= PERF_EVENT_STATE_OFF)
619 return leader->state;
624 static __always_inline void
625 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
627 enum perf_event_state state = __perf_effective_state(event);
628 u64 delta = now - event->tstamp;
630 *enabled = event->total_time_enabled;
631 if (state >= PERF_EVENT_STATE_INACTIVE)
634 *running = event->total_time_running;
635 if (state >= PERF_EVENT_STATE_ACTIVE)
639 static void perf_event_update_time(struct perf_event *event)
641 u64 now = perf_event_time(event);
643 __perf_update_times(event, now, &event->total_time_enabled,
644 &event->total_time_running);
648 static void perf_event_update_sibling_time(struct perf_event *leader)
650 struct perf_event *sibling;
652 for_each_sibling_event(sibling, leader)
653 perf_event_update_time(sibling);
657 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
659 if (event->state == state)
662 perf_event_update_time(event);
664 * If a group leader gets enabled/disabled all its siblings
667 if ((event->state < 0) ^ (state < 0))
668 perf_event_update_sibling_time(event);
670 WRITE_ONCE(event->state, state);
673 #ifdef CONFIG_CGROUP_PERF
676 perf_cgroup_match(struct perf_event *event)
678 struct perf_event_context *ctx = event->ctx;
679 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
681 /* @event doesn't care about cgroup */
685 /* wants specific cgroup scope but @cpuctx isn't associated with any */
690 * Cgroup scoping is recursive. An event enabled for a cgroup is
691 * also enabled for all its descendant cgroups. If @cpuctx's
692 * cgroup is a descendant of @event's (the test covers identity
693 * case), it's a match.
695 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
696 event->cgrp->css.cgroup);
699 static inline void perf_detach_cgroup(struct perf_event *event)
701 css_put(&event->cgrp->css);
705 static inline int is_cgroup_event(struct perf_event *event)
707 return event->cgrp != NULL;
710 static inline u64 perf_cgroup_event_time(struct perf_event *event)
712 struct perf_cgroup_info *t;
714 t = per_cpu_ptr(event->cgrp->info, event->cpu);
718 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
720 struct perf_cgroup_info *info;
725 info = this_cpu_ptr(cgrp->info);
727 info->time += now - info->timestamp;
728 info->timestamp = now;
731 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
733 struct perf_cgroup *cgrp = cpuctx->cgrp;
734 struct cgroup_subsys_state *css;
737 for (css = &cgrp->css; css; css = css->parent) {
738 cgrp = container_of(css, struct perf_cgroup, css);
739 __update_cgrp_time(cgrp);
744 static inline void update_cgrp_time_from_event(struct perf_event *event)
746 struct perf_cgroup *cgrp;
749 * ensure we access cgroup data only when needed and
750 * when we know the cgroup is pinned (css_get)
752 if (!is_cgroup_event(event))
755 cgrp = perf_cgroup_from_task(current, event->ctx);
757 * Do not update time when cgroup is not active
759 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
760 __update_cgrp_time(event->cgrp);
764 perf_cgroup_set_timestamp(struct task_struct *task,
765 struct perf_event_context *ctx)
767 struct perf_cgroup *cgrp;
768 struct perf_cgroup_info *info;
769 struct cgroup_subsys_state *css;
772 * ctx->lock held by caller
773 * ensure we do not access cgroup data
774 * unless we have the cgroup pinned (css_get)
776 if (!task || !ctx->nr_cgroups)
779 cgrp = perf_cgroup_from_task(task, ctx);
781 for (css = &cgrp->css; css; css = css->parent) {
782 cgrp = container_of(css, struct perf_cgroup, css);
783 info = this_cpu_ptr(cgrp->info);
784 info->timestamp = ctx->timestamp;
788 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
790 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
791 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
794 * reschedule events based on the cgroup constraint of task.
796 * mode SWOUT : schedule out everything
797 * mode SWIN : schedule in based on cgroup for next
799 static void perf_cgroup_switch(struct task_struct *task, int mode)
801 struct perf_cpu_context *cpuctx;
802 struct list_head *list;
806 * Disable interrupts and preemption to avoid this CPU's
807 * cgrp_cpuctx_entry to change under us.
809 local_irq_save(flags);
811 list = this_cpu_ptr(&cgrp_cpuctx_list);
812 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
813 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
815 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
816 perf_pmu_disable(cpuctx->ctx.pmu);
818 if (mode & PERF_CGROUP_SWOUT) {
819 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
821 * must not be done before ctxswout due
822 * to event_filter_match() in event_sched_out()
827 if (mode & PERF_CGROUP_SWIN) {
828 WARN_ON_ONCE(cpuctx->cgrp);
830 * set cgrp before ctxsw in to allow
831 * event_filter_match() to not have to pass
833 * we pass the cpuctx->ctx to perf_cgroup_from_task()
834 * because cgorup events are only per-cpu
836 cpuctx->cgrp = perf_cgroup_from_task(task,
838 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
840 perf_pmu_enable(cpuctx->ctx.pmu);
841 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
844 local_irq_restore(flags);
847 static inline void perf_cgroup_sched_out(struct task_struct *task,
848 struct task_struct *next)
850 struct perf_cgroup *cgrp1;
851 struct perf_cgroup *cgrp2 = NULL;
855 * we come here when we know perf_cgroup_events > 0
856 * we do not need to pass the ctx here because we know
857 * we are holding the rcu lock
859 cgrp1 = perf_cgroup_from_task(task, NULL);
860 cgrp2 = perf_cgroup_from_task(next, NULL);
863 * only schedule out current cgroup events if we know
864 * that we are switching to a different cgroup. Otherwise,
865 * do no touch the cgroup events.
868 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
873 static inline void perf_cgroup_sched_in(struct task_struct *prev,
874 struct task_struct *task)
876 struct perf_cgroup *cgrp1;
877 struct perf_cgroup *cgrp2 = NULL;
881 * we come here when we know perf_cgroup_events > 0
882 * we do not need to pass the ctx here because we know
883 * we are holding the rcu lock
885 cgrp1 = perf_cgroup_from_task(task, NULL);
886 cgrp2 = perf_cgroup_from_task(prev, NULL);
889 * only need to schedule in cgroup events if we are changing
890 * cgroup during ctxsw. Cgroup events were not scheduled
891 * out of ctxsw out if that was not the case.
894 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
899 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
900 struct perf_event_attr *attr,
901 struct perf_event *group_leader)
903 struct perf_cgroup *cgrp;
904 struct cgroup_subsys_state *css;
905 struct fd f = fdget(fd);
911 css = css_tryget_online_from_dir(f.file->f_path.dentry,
912 &perf_event_cgrp_subsys);
918 cgrp = container_of(css, struct perf_cgroup, css);
922 * all events in a group must monitor
923 * the same cgroup because a task belongs
924 * to only one perf cgroup at a time
926 if (group_leader && group_leader->cgrp != cgrp) {
927 perf_detach_cgroup(event);
936 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
938 struct perf_cgroup_info *t;
939 t = per_cpu_ptr(event->cgrp->info, event->cpu);
940 event->shadow_ctx_time = now - t->timestamp;
944 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
945 * cleared when last cgroup event is removed.
948 list_update_cgroup_event(struct perf_event *event,
949 struct perf_event_context *ctx, bool add)
951 struct perf_cpu_context *cpuctx;
952 struct list_head *cpuctx_entry;
954 if (!is_cgroup_event(event))
958 * Because cgroup events are always per-cpu events,
959 * this will always be called from the right CPU.
961 cpuctx = __get_cpu_context(ctx);
964 * Since setting cpuctx->cgrp is conditional on the current @cgrp
965 * matching the event's cgroup, we must do this for every new event,
966 * because if the first would mismatch, the second would not try again
967 * and we would leave cpuctx->cgrp unset.
969 if (add && !cpuctx->cgrp) {
970 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
972 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
976 if (add && ctx->nr_cgroups++)
978 else if (!add && --ctx->nr_cgroups)
981 /* no cgroup running */
985 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
987 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
989 list_del(cpuctx_entry);
992 #else /* !CONFIG_CGROUP_PERF */
995 perf_cgroup_match(struct perf_event *event)
1000 static inline void perf_detach_cgroup(struct perf_event *event)
1003 static inline int is_cgroup_event(struct perf_event *event)
1008 static inline void update_cgrp_time_from_event(struct perf_event *event)
1012 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1016 static inline void perf_cgroup_sched_out(struct task_struct *task,
1017 struct task_struct *next)
1021 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1022 struct task_struct *task)
1026 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1027 struct perf_event_attr *attr,
1028 struct perf_event *group_leader)
1034 perf_cgroup_set_timestamp(struct task_struct *task,
1035 struct perf_event_context *ctx)
1040 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1045 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1049 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1055 list_update_cgroup_event(struct perf_event *event,
1056 struct perf_event_context *ctx, bool add)
1063 * set default to be dependent on timer tick just
1064 * like original code
1066 #define PERF_CPU_HRTIMER (1000 / HZ)
1068 * function must be called with interrupts disabled
1070 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1072 struct perf_cpu_context *cpuctx;
1075 lockdep_assert_irqs_disabled();
1077 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1078 rotations = perf_rotate_context(cpuctx);
1080 raw_spin_lock(&cpuctx->hrtimer_lock);
1082 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1084 cpuctx->hrtimer_active = 0;
1085 raw_spin_unlock(&cpuctx->hrtimer_lock);
1087 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1090 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1092 struct hrtimer *timer = &cpuctx->hrtimer;
1093 struct pmu *pmu = cpuctx->ctx.pmu;
1096 /* no multiplexing needed for SW PMU */
1097 if (pmu->task_ctx_nr == perf_sw_context)
1101 * check default is sane, if not set then force to
1102 * default interval (1/tick)
1104 interval = pmu->hrtimer_interval_ms;
1106 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1108 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1110 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1111 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1112 timer->function = perf_mux_hrtimer_handler;
1115 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1117 struct hrtimer *timer = &cpuctx->hrtimer;
1118 struct pmu *pmu = cpuctx->ctx.pmu;
1119 unsigned long flags;
1121 /* not for SW PMU */
1122 if (pmu->task_ctx_nr == perf_sw_context)
1125 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1126 if (!cpuctx->hrtimer_active) {
1127 cpuctx->hrtimer_active = 1;
1128 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1129 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1131 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1136 void perf_pmu_disable(struct pmu *pmu)
1138 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1140 pmu->pmu_disable(pmu);
1143 void perf_pmu_enable(struct pmu *pmu)
1145 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1147 pmu->pmu_enable(pmu);
1150 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1153 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1154 * perf_event_task_tick() are fully serialized because they're strictly cpu
1155 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1156 * disabled, while perf_event_task_tick is called from IRQ context.
1158 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1160 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1162 lockdep_assert_irqs_disabled();
1164 WARN_ON(!list_empty(&ctx->active_ctx_list));
1166 list_add(&ctx->active_ctx_list, head);
1169 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1171 lockdep_assert_irqs_disabled();
1173 WARN_ON(list_empty(&ctx->active_ctx_list));
1175 list_del_init(&ctx->active_ctx_list);
1178 static void get_ctx(struct perf_event_context *ctx)
1180 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1183 static void free_ctx(struct rcu_head *head)
1185 struct perf_event_context *ctx;
1187 ctx = container_of(head, struct perf_event_context, rcu_head);
1188 kfree(ctx->task_ctx_data);
1192 static void put_ctx(struct perf_event_context *ctx)
1194 if (atomic_dec_and_test(&ctx->refcount)) {
1195 if (ctx->parent_ctx)
1196 put_ctx(ctx->parent_ctx);
1197 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1198 put_task_struct(ctx->task);
1199 call_rcu(&ctx->rcu_head, free_ctx);
1204 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1205 * perf_pmu_migrate_context() we need some magic.
1207 * Those places that change perf_event::ctx will hold both
1208 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1210 * Lock ordering is by mutex address. There are two other sites where
1211 * perf_event_context::mutex nests and those are:
1213 * - perf_event_exit_task_context() [ child , 0 ]
1214 * perf_event_exit_event()
1215 * put_event() [ parent, 1 ]
1217 * - perf_event_init_context() [ parent, 0 ]
1218 * inherit_task_group()
1221 * perf_event_alloc()
1223 * perf_try_init_event() [ child , 1 ]
1225 * While it appears there is an obvious deadlock here -- the parent and child
1226 * nesting levels are inverted between the two. This is in fact safe because
1227 * life-time rules separate them. That is an exiting task cannot fork, and a
1228 * spawning task cannot (yet) exit.
1230 * But remember that that these are parent<->child context relations, and
1231 * migration does not affect children, therefore these two orderings should not
1234 * The change in perf_event::ctx does not affect children (as claimed above)
1235 * because the sys_perf_event_open() case will install a new event and break
1236 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1237 * concerned with cpuctx and that doesn't have children.
1239 * The places that change perf_event::ctx will issue:
1241 * perf_remove_from_context();
1242 * synchronize_rcu();
1243 * perf_install_in_context();
1245 * to affect the change. The remove_from_context() + synchronize_rcu() should
1246 * quiesce the event, after which we can install it in the new location. This
1247 * means that only external vectors (perf_fops, prctl) can perturb the event
1248 * while in transit. Therefore all such accessors should also acquire
1249 * perf_event_context::mutex to serialize against this.
1251 * However; because event->ctx can change while we're waiting to acquire
1252 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1257 * task_struct::perf_event_mutex
1258 * perf_event_context::mutex
1259 * perf_event::child_mutex;
1260 * perf_event_context::lock
1261 * perf_event::mmap_mutex
1263 * perf_addr_filters_head::lock
1267 * cpuctx->mutex / perf_event_context::mutex
1269 static struct perf_event_context *
1270 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1272 struct perf_event_context *ctx;
1276 ctx = READ_ONCE(event->ctx);
1277 if (!atomic_inc_not_zero(&ctx->refcount)) {
1283 mutex_lock_nested(&ctx->mutex, nesting);
1284 if (event->ctx != ctx) {
1285 mutex_unlock(&ctx->mutex);
1293 static inline struct perf_event_context *
1294 perf_event_ctx_lock(struct perf_event *event)
1296 return perf_event_ctx_lock_nested(event, 0);
1299 static void perf_event_ctx_unlock(struct perf_event *event,
1300 struct perf_event_context *ctx)
1302 mutex_unlock(&ctx->mutex);
1307 * This must be done under the ctx->lock, such as to serialize against
1308 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1309 * calling scheduler related locks and ctx->lock nests inside those.
1311 static __must_check struct perf_event_context *
1312 unclone_ctx(struct perf_event_context *ctx)
1314 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1316 lockdep_assert_held(&ctx->lock);
1319 ctx->parent_ctx = NULL;
1325 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1330 * only top level events have the pid namespace they were created in
1333 event = event->parent;
1335 nr = __task_pid_nr_ns(p, type, event->ns);
1336 /* avoid -1 if it is idle thread or runs in another ns */
1337 if (!nr && !pid_alive(p))
1342 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1344 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1347 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1349 return perf_event_pid_type(event, p, PIDTYPE_PID);
1353 * If we inherit events we want to return the parent event id
1356 static u64 primary_event_id(struct perf_event *event)
1361 id = event->parent->id;
1367 * Get the perf_event_context for a task and lock it.
1369 * This has to cope with with the fact that until it is locked,
1370 * the context could get moved to another task.
1372 static struct perf_event_context *
1373 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1375 struct perf_event_context *ctx;
1379 * One of the few rules of preemptible RCU is that one cannot do
1380 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1381 * part of the read side critical section was irqs-enabled -- see
1382 * rcu_read_unlock_special().
1384 * Since ctx->lock nests under rq->lock we must ensure the entire read
1385 * side critical section has interrupts disabled.
1387 local_irq_save(*flags);
1389 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1392 * If this context is a clone of another, it might
1393 * get swapped for another underneath us by
1394 * perf_event_task_sched_out, though the
1395 * rcu_read_lock() protects us from any context
1396 * getting freed. Lock the context and check if it
1397 * got swapped before we could get the lock, and retry
1398 * if so. If we locked the right context, then it
1399 * can't get swapped on us any more.
1401 raw_spin_lock(&ctx->lock);
1402 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1403 raw_spin_unlock(&ctx->lock);
1405 local_irq_restore(*flags);
1409 if (ctx->task == TASK_TOMBSTONE ||
1410 !atomic_inc_not_zero(&ctx->refcount)) {
1411 raw_spin_unlock(&ctx->lock);
1414 WARN_ON_ONCE(ctx->task != task);
1419 local_irq_restore(*flags);
1424 * Get the context for a task and increment its pin_count so it
1425 * can't get swapped to another task. This also increments its
1426 * reference count so that the context can't get freed.
1428 static struct perf_event_context *
1429 perf_pin_task_context(struct task_struct *task, int ctxn)
1431 struct perf_event_context *ctx;
1432 unsigned long flags;
1434 ctx = perf_lock_task_context(task, ctxn, &flags);
1437 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1442 static void perf_unpin_context(struct perf_event_context *ctx)
1444 unsigned long flags;
1446 raw_spin_lock_irqsave(&ctx->lock, flags);
1448 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1452 * Update the record of the current time in a context.
1454 static void update_context_time(struct perf_event_context *ctx)
1456 u64 now = perf_clock();
1458 ctx->time += now - ctx->timestamp;
1459 ctx->timestamp = now;
1462 static u64 perf_event_time(struct perf_event *event)
1464 struct perf_event_context *ctx = event->ctx;
1466 if (is_cgroup_event(event))
1467 return perf_cgroup_event_time(event);
1469 return ctx ? ctx->time : 0;
1472 static enum event_type_t get_event_type(struct perf_event *event)
1474 struct perf_event_context *ctx = event->ctx;
1475 enum event_type_t event_type;
1477 lockdep_assert_held(&ctx->lock);
1480 * It's 'group type', really, because if our group leader is
1481 * pinned, so are we.
1483 if (event->group_leader != event)
1484 event = event->group_leader;
1486 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1488 event_type |= EVENT_CPU;
1494 * Helper function to initialize event group nodes.
1496 static void init_event_group(struct perf_event *event)
1498 RB_CLEAR_NODE(&event->group_node);
1499 event->group_index = 0;
1503 * Extract pinned or flexible groups from the context
1504 * based on event attrs bits.
1506 static struct perf_event_groups *
1507 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1509 if (event->attr.pinned)
1510 return &ctx->pinned_groups;
1512 return &ctx->flexible_groups;
1516 * Helper function to initializes perf_event_group trees.
1518 static void perf_event_groups_init(struct perf_event_groups *groups)
1520 groups->tree = RB_ROOT;
1525 * Compare function for event groups;
1527 * Implements complex key that first sorts by CPU and then by virtual index
1528 * which provides ordering when rotating groups for the same CPU.
1531 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1533 if (left->cpu < right->cpu)
1535 if (left->cpu > right->cpu)
1538 if (left->group_index < right->group_index)
1540 if (left->group_index > right->group_index)
1547 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1548 * key (see perf_event_groups_less). This places it last inside the CPU
1552 perf_event_groups_insert(struct perf_event_groups *groups,
1553 struct perf_event *event)
1555 struct perf_event *node_event;
1556 struct rb_node *parent;
1557 struct rb_node **node;
1559 event->group_index = ++groups->index;
1561 node = &groups->tree.rb_node;
1566 node_event = container_of(*node, struct perf_event, group_node);
1568 if (perf_event_groups_less(event, node_event))
1569 node = &parent->rb_left;
1571 node = &parent->rb_right;
1574 rb_link_node(&event->group_node, parent, node);
1575 rb_insert_color(&event->group_node, &groups->tree);
1579 * Helper function to insert event into the pinned or flexible groups.
1582 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1584 struct perf_event_groups *groups;
1586 groups = get_event_groups(event, ctx);
1587 perf_event_groups_insert(groups, event);
1591 * Delete a group from a tree.
1594 perf_event_groups_delete(struct perf_event_groups *groups,
1595 struct perf_event *event)
1597 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1598 RB_EMPTY_ROOT(&groups->tree));
1600 rb_erase(&event->group_node, &groups->tree);
1601 init_event_group(event);
1605 * Helper function to delete event from its groups.
1608 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1610 struct perf_event_groups *groups;
1612 groups = get_event_groups(event, ctx);
1613 perf_event_groups_delete(groups, event);
1617 * Get the leftmost event in the @cpu subtree.
1619 static struct perf_event *
1620 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1622 struct perf_event *node_event = NULL, *match = NULL;
1623 struct rb_node *node = groups->tree.rb_node;
1626 node_event = container_of(node, struct perf_event, group_node);
1628 if (cpu < node_event->cpu) {
1629 node = node->rb_left;
1630 } else if (cpu > node_event->cpu) {
1631 node = node->rb_right;
1634 node = node->rb_left;
1642 * Like rb_entry_next_safe() for the @cpu subtree.
1644 static struct perf_event *
1645 perf_event_groups_next(struct perf_event *event)
1647 struct perf_event *next;
1649 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1650 if (next && next->cpu == event->cpu)
1657 * Iterate through the whole groups tree.
1659 #define perf_event_groups_for_each(event, groups) \
1660 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1661 typeof(*event), group_node); event; \
1662 event = rb_entry_safe(rb_next(&event->group_node), \
1663 typeof(*event), group_node))
1666 * Add an event from the lists for its context.
1667 * Must be called with ctx->mutex and ctx->lock held.
1670 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1672 lockdep_assert_held(&ctx->lock);
1674 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1675 event->attach_state |= PERF_ATTACH_CONTEXT;
1677 event->tstamp = perf_event_time(event);
1680 * If we're a stand alone event or group leader, we go to the context
1681 * list, group events are kept attached to the group so that
1682 * perf_group_detach can, at all times, locate all siblings.
1684 if (event->group_leader == event) {
1685 event->group_caps = event->event_caps;
1686 add_event_to_groups(event, ctx);
1689 list_update_cgroup_event(event, ctx, true);
1691 list_add_rcu(&event->event_entry, &ctx->event_list);
1693 if (event->attr.inherit_stat)
1700 * Initialize event state based on the perf_event_attr::disabled.
1702 static inline void perf_event__state_init(struct perf_event *event)
1704 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1705 PERF_EVENT_STATE_INACTIVE;
1708 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1710 int entry = sizeof(u64); /* value */
1714 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1715 size += sizeof(u64);
1717 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1718 size += sizeof(u64);
1720 if (event->attr.read_format & PERF_FORMAT_ID)
1721 entry += sizeof(u64);
1723 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1725 size += sizeof(u64);
1729 event->read_size = size;
1732 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1734 struct perf_sample_data *data;
1737 if (sample_type & PERF_SAMPLE_IP)
1738 size += sizeof(data->ip);
1740 if (sample_type & PERF_SAMPLE_ADDR)
1741 size += sizeof(data->addr);
1743 if (sample_type & PERF_SAMPLE_PERIOD)
1744 size += sizeof(data->period);
1746 if (sample_type & PERF_SAMPLE_WEIGHT)
1747 size += sizeof(data->weight);
1749 if (sample_type & PERF_SAMPLE_READ)
1750 size += event->read_size;
1752 if (sample_type & PERF_SAMPLE_DATA_SRC)
1753 size += sizeof(data->data_src.val);
1755 if (sample_type & PERF_SAMPLE_TRANSACTION)
1756 size += sizeof(data->txn);
1758 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1759 size += sizeof(data->phys_addr);
1761 event->header_size = size;
1765 * Called at perf_event creation and when events are attached/detached from a
1768 static void perf_event__header_size(struct perf_event *event)
1770 __perf_event_read_size(event,
1771 event->group_leader->nr_siblings);
1772 __perf_event_header_size(event, event->attr.sample_type);
1775 static void perf_event__id_header_size(struct perf_event *event)
1777 struct perf_sample_data *data;
1778 u64 sample_type = event->attr.sample_type;
1781 if (sample_type & PERF_SAMPLE_TID)
1782 size += sizeof(data->tid_entry);
1784 if (sample_type & PERF_SAMPLE_TIME)
1785 size += sizeof(data->time);
1787 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1788 size += sizeof(data->id);
1790 if (sample_type & PERF_SAMPLE_ID)
1791 size += sizeof(data->id);
1793 if (sample_type & PERF_SAMPLE_STREAM_ID)
1794 size += sizeof(data->stream_id);
1796 if (sample_type & PERF_SAMPLE_CPU)
1797 size += sizeof(data->cpu_entry);
1799 event->id_header_size = size;
1802 static bool perf_event_validate_size(struct perf_event *event)
1805 * The values computed here will be over-written when we actually
1808 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1809 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1810 perf_event__id_header_size(event);
1813 * Sum the lot; should not exceed the 64k limit we have on records.
1814 * Conservative limit to allow for callchains and other variable fields.
1816 if (event->read_size + event->header_size +
1817 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1823 static void perf_group_attach(struct perf_event *event)
1825 struct perf_event *group_leader = event->group_leader, *pos;
1827 lockdep_assert_held(&event->ctx->lock);
1830 * We can have double attach due to group movement in perf_event_open.
1832 if (event->attach_state & PERF_ATTACH_GROUP)
1835 event->attach_state |= PERF_ATTACH_GROUP;
1837 if (group_leader == event)
1840 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1842 group_leader->group_caps &= event->event_caps;
1844 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1845 group_leader->nr_siblings++;
1847 perf_event__header_size(group_leader);
1849 for_each_sibling_event(pos, group_leader)
1850 perf_event__header_size(pos);
1854 * Remove an event from the lists for its context.
1855 * Must be called with ctx->mutex and ctx->lock held.
1858 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1860 WARN_ON_ONCE(event->ctx != ctx);
1861 lockdep_assert_held(&ctx->lock);
1864 * We can have double detach due to exit/hot-unplug + close.
1866 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1869 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1871 list_update_cgroup_event(event, ctx, false);
1874 if (event->attr.inherit_stat)
1877 list_del_rcu(&event->event_entry);
1879 if (event->group_leader == event)
1880 del_event_from_groups(event, ctx);
1883 * If event was in error state, then keep it
1884 * that way, otherwise bogus counts will be
1885 * returned on read(). The only way to get out
1886 * of error state is by explicit re-enabling
1889 if (event->state > PERF_EVENT_STATE_OFF)
1890 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1895 static void perf_group_detach(struct perf_event *event)
1897 struct perf_event *sibling, *tmp;
1898 struct perf_event_context *ctx = event->ctx;
1900 lockdep_assert_held(&ctx->lock);
1903 * We can have double detach due to exit/hot-unplug + close.
1905 if (!(event->attach_state & PERF_ATTACH_GROUP))
1908 event->attach_state &= ~PERF_ATTACH_GROUP;
1911 * If this is a sibling, remove it from its group.
1913 if (event->group_leader != event) {
1914 list_del_init(&event->sibling_list);
1915 event->group_leader->nr_siblings--;
1920 * If this was a group event with sibling events then
1921 * upgrade the siblings to singleton events by adding them
1922 * to whatever list we are on.
1924 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1926 sibling->group_leader = sibling;
1927 list_del_init(&sibling->sibling_list);
1929 /* Inherit group flags from the previous leader */
1930 sibling->group_caps = event->group_caps;
1932 if (!RB_EMPTY_NODE(&event->group_node)) {
1933 add_event_to_groups(sibling, event->ctx);
1935 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1936 struct list_head *list = sibling->attr.pinned ?
1937 &ctx->pinned_active : &ctx->flexible_active;
1939 list_add_tail(&sibling->active_list, list);
1943 WARN_ON_ONCE(sibling->ctx != event->ctx);
1947 perf_event__header_size(event->group_leader);
1949 for_each_sibling_event(tmp, event->group_leader)
1950 perf_event__header_size(tmp);
1953 static bool is_orphaned_event(struct perf_event *event)
1955 return event->state == PERF_EVENT_STATE_DEAD;
1958 static inline int __pmu_filter_match(struct perf_event *event)
1960 struct pmu *pmu = event->pmu;
1961 return pmu->filter_match ? pmu->filter_match(event) : 1;
1965 * Check whether we should attempt to schedule an event group based on
1966 * PMU-specific filtering. An event group can consist of HW and SW events,
1967 * potentially with a SW leader, so we must check all the filters, to
1968 * determine whether a group is schedulable:
1970 static inline int pmu_filter_match(struct perf_event *event)
1972 struct perf_event *sibling;
1974 if (!__pmu_filter_match(event))
1977 for_each_sibling_event(sibling, event) {
1978 if (!__pmu_filter_match(sibling))
1986 event_filter_match(struct perf_event *event)
1988 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1989 perf_cgroup_match(event) && pmu_filter_match(event);
1993 event_sched_out(struct perf_event *event,
1994 struct perf_cpu_context *cpuctx,
1995 struct perf_event_context *ctx)
1997 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1999 WARN_ON_ONCE(event->ctx != ctx);
2000 lockdep_assert_held(&ctx->lock);
2002 if (event->state != PERF_EVENT_STATE_ACTIVE)
2006 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2007 * we can schedule events _OUT_ individually through things like
2008 * __perf_remove_from_context().
2010 list_del_init(&event->active_list);
2012 perf_pmu_disable(event->pmu);
2014 event->pmu->del(event, 0);
2017 if (READ_ONCE(event->pending_disable) >= 0) {
2018 WRITE_ONCE(event->pending_disable, -1);
2019 state = PERF_EVENT_STATE_OFF;
2021 perf_event_set_state(event, state);
2023 if (!is_software_event(event))
2024 cpuctx->active_oncpu--;
2025 if (!--ctx->nr_active)
2026 perf_event_ctx_deactivate(ctx);
2027 if (event->attr.freq && event->attr.sample_freq)
2029 if (event->attr.exclusive || !cpuctx->active_oncpu)
2030 cpuctx->exclusive = 0;
2032 perf_pmu_enable(event->pmu);
2036 group_sched_out(struct perf_event *group_event,
2037 struct perf_cpu_context *cpuctx,
2038 struct perf_event_context *ctx)
2040 struct perf_event *event;
2042 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2045 perf_pmu_disable(ctx->pmu);
2047 event_sched_out(group_event, cpuctx, ctx);
2050 * Schedule out siblings (if any):
2052 for_each_sibling_event(event, group_event)
2053 event_sched_out(event, cpuctx, ctx);
2055 perf_pmu_enable(ctx->pmu);
2057 if (group_event->attr.exclusive)
2058 cpuctx->exclusive = 0;
2061 #define DETACH_GROUP 0x01UL
2064 * Cross CPU call to remove a performance event
2066 * We disable the event on the hardware level first. After that we
2067 * remove it from the context list.
2070 __perf_remove_from_context(struct perf_event *event,
2071 struct perf_cpu_context *cpuctx,
2072 struct perf_event_context *ctx,
2075 unsigned long flags = (unsigned long)info;
2077 if (ctx->is_active & EVENT_TIME) {
2078 update_context_time(ctx);
2079 update_cgrp_time_from_cpuctx(cpuctx);
2082 event_sched_out(event, cpuctx, ctx);
2083 if (flags & DETACH_GROUP)
2084 perf_group_detach(event);
2085 list_del_event(event, ctx);
2087 if (!ctx->nr_events && ctx->is_active) {
2090 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2091 cpuctx->task_ctx = NULL;
2097 * Remove the event from a task's (or a CPU's) list of events.
2099 * If event->ctx is a cloned context, callers must make sure that
2100 * every task struct that event->ctx->task could possibly point to
2101 * remains valid. This is OK when called from perf_release since
2102 * that only calls us on the top-level context, which can't be a clone.
2103 * When called from perf_event_exit_task, it's OK because the
2104 * context has been detached from its task.
2106 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2108 struct perf_event_context *ctx = event->ctx;
2110 lockdep_assert_held(&ctx->mutex);
2112 event_function_call(event, __perf_remove_from_context, (void *)flags);
2115 * The above event_function_call() can NO-OP when it hits
2116 * TASK_TOMBSTONE. In that case we must already have been detached
2117 * from the context (by perf_event_exit_event()) but the grouping
2118 * might still be in-tact.
2120 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2121 if ((flags & DETACH_GROUP) &&
2122 (event->attach_state & PERF_ATTACH_GROUP)) {
2124 * Since in that case we cannot possibly be scheduled, simply
2127 raw_spin_lock_irq(&ctx->lock);
2128 perf_group_detach(event);
2129 raw_spin_unlock_irq(&ctx->lock);
2134 * Cross CPU call to disable a performance event
2136 static void __perf_event_disable(struct perf_event *event,
2137 struct perf_cpu_context *cpuctx,
2138 struct perf_event_context *ctx,
2141 if (event->state < PERF_EVENT_STATE_INACTIVE)
2144 if (ctx->is_active & EVENT_TIME) {
2145 update_context_time(ctx);
2146 update_cgrp_time_from_event(event);
2149 if (event == event->group_leader)
2150 group_sched_out(event, cpuctx, ctx);
2152 event_sched_out(event, cpuctx, ctx);
2154 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2160 * If event->ctx is a cloned context, callers must make sure that
2161 * every task struct that event->ctx->task could possibly point to
2162 * remains valid. This condition is satisifed when called through
2163 * perf_event_for_each_child or perf_event_for_each because they
2164 * hold the top-level event's child_mutex, so any descendant that
2165 * goes to exit will block in perf_event_exit_event().
2167 * When called from perf_pending_event it's OK because event->ctx
2168 * is the current context on this CPU and preemption is disabled,
2169 * hence we can't get into perf_event_task_sched_out for this context.
2171 static void _perf_event_disable(struct perf_event *event)
2173 struct perf_event_context *ctx = event->ctx;
2175 raw_spin_lock_irq(&ctx->lock);
2176 if (event->state <= PERF_EVENT_STATE_OFF) {
2177 raw_spin_unlock_irq(&ctx->lock);
2180 raw_spin_unlock_irq(&ctx->lock);
2182 event_function_call(event, __perf_event_disable, NULL);
2185 void perf_event_disable_local(struct perf_event *event)
2187 event_function_local(event, __perf_event_disable, NULL);
2191 * Strictly speaking kernel users cannot create groups and therefore this
2192 * interface does not need the perf_event_ctx_lock() magic.
2194 void perf_event_disable(struct perf_event *event)
2196 struct perf_event_context *ctx;
2198 ctx = perf_event_ctx_lock(event);
2199 _perf_event_disable(event);
2200 perf_event_ctx_unlock(event, ctx);
2202 EXPORT_SYMBOL_GPL(perf_event_disable);
2204 void perf_event_disable_inatomic(struct perf_event *event)
2206 WRITE_ONCE(event->pending_disable, smp_processor_id());
2207 /* can fail, see perf_pending_event_disable() */
2208 irq_work_queue(&event->pending);
2211 static void perf_set_shadow_time(struct perf_event *event,
2212 struct perf_event_context *ctx)
2215 * use the correct time source for the time snapshot
2217 * We could get by without this by leveraging the
2218 * fact that to get to this function, the caller
2219 * has most likely already called update_context_time()
2220 * and update_cgrp_time_xx() and thus both timestamp
2221 * are identical (or very close). Given that tstamp is,
2222 * already adjusted for cgroup, we could say that:
2223 * tstamp - ctx->timestamp
2225 * tstamp - cgrp->timestamp.
2227 * Then, in perf_output_read(), the calculation would
2228 * work with no changes because:
2229 * - event is guaranteed scheduled in
2230 * - no scheduled out in between
2231 * - thus the timestamp would be the same
2233 * But this is a bit hairy.
2235 * So instead, we have an explicit cgroup call to remain
2236 * within the time time source all along. We believe it
2237 * is cleaner and simpler to understand.
2239 if (is_cgroup_event(event))
2240 perf_cgroup_set_shadow_time(event, event->tstamp);
2242 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2245 #define MAX_INTERRUPTS (~0ULL)
2247 static void perf_log_throttle(struct perf_event *event, int enable);
2248 static void perf_log_itrace_start(struct perf_event *event);
2251 event_sched_in(struct perf_event *event,
2252 struct perf_cpu_context *cpuctx,
2253 struct perf_event_context *ctx)
2257 lockdep_assert_held(&ctx->lock);
2259 if (event->state <= PERF_EVENT_STATE_OFF)
2262 WRITE_ONCE(event->oncpu, smp_processor_id());
2264 * Order event::oncpu write to happen before the ACTIVE state is
2265 * visible. This allows perf_event_{stop,read}() to observe the correct
2266 * ->oncpu if it sees ACTIVE.
2269 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2272 * Unthrottle events, since we scheduled we might have missed several
2273 * ticks already, also for a heavily scheduling task there is little
2274 * guarantee it'll get a tick in a timely manner.
2276 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2277 perf_log_throttle(event, 1);
2278 event->hw.interrupts = 0;
2281 perf_pmu_disable(event->pmu);
2283 perf_set_shadow_time(event, ctx);
2285 perf_log_itrace_start(event);
2287 if (event->pmu->add(event, PERF_EF_START)) {
2288 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2294 if (!is_software_event(event))
2295 cpuctx->active_oncpu++;
2296 if (!ctx->nr_active++)
2297 perf_event_ctx_activate(ctx);
2298 if (event->attr.freq && event->attr.sample_freq)
2301 if (event->attr.exclusive)
2302 cpuctx->exclusive = 1;
2305 perf_pmu_enable(event->pmu);
2311 group_sched_in(struct perf_event *group_event,
2312 struct perf_cpu_context *cpuctx,
2313 struct perf_event_context *ctx)
2315 struct perf_event *event, *partial_group = NULL;
2316 struct pmu *pmu = ctx->pmu;
2318 if (group_event->state == PERF_EVENT_STATE_OFF)
2321 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2323 if (event_sched_in(group_event, cpuctx, ctx)) {
2324 pmu->cancel_txn(pmu);
2325 perf_mux_hrtimer_restart(cpuctx);
2330 * Schedule in siblings as one group (if any):
2332 for_each_sibling_event(event, group_event) {
2333 if (event_sched_in(event, cpuctx, ctx)) {
2334 partial_group = event;
2339 if (!pmu->commit_txn(pmu))
2344 * Groups can be scheduled in as one unit only, so undo any
2345 * partial group before returning:
2346 * The events up to the failed event are scheduled out normally.
2348 for_each_sibling_event(event, group_event) {
2349 if (event == partial_group)
2352 event_sched_out(event, cpuctx, ctx);
2354 event_sched_out(group_event, cpuctx, ctx);
2356 pmu->cancel_txn(pmu);
2358 perf_mux_hrtimer_restart(cpuctx);
2364 * Work out whether we can put this event group on the CPU now.
2366 static int group_can_go_on(struct perf_event *event,
2367 struct perf_cpu_context *cpuctx,
2371 * Groups consisting entirely of software events can always go on.
2373 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2376 * If an exclusive group is already on, no other hardware
2379 if (cpuctx->exclusive)
2382 * If this group is exclusive and there are already
2383 * events on the CPU, it can't go on.
2385 if (event->attr.exclusive && cpuctx->active_oncpu)
2388 * Otherwise, try to add it if all previous groups were able
2394 static void add_event_to_ctx(struct perf_event *event,
2395 struct perf_event_context *ctx)
2397 list_add_event(event, ctx);
2398 perf_group_attach(event);
2401 static void ctx_sched_out(struct perf_event_context *ctx,
2402 struct perf_cpu_context *cpuctx,
2403 enum event_type_t event_type);
2405 ctx_sched_in(struct perf_event_context *ctx,
2406 struct perf_cpu_context *cpuctx,
2407 enum event_type_t event_type,
2408 struct task_struct *task);
2410 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2411 struct perf_event_context *ctx,
2412 enum event_type_t event_type)
2414 if (!cpuctx->task_ctx)
2417 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2420 ctx_sched_out(ctx, cpuctx, event_type);
2423 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2424 struct perf_event_context *ctx,
2425 struct task_struct *task)
2427 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2429 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2430 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2432 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2436 * We want to maintain the following priority of scheduling:
2437 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2438 * - task pinned (EVENT_PINNED)
2439 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2440 * - task flexible (EVENT_FLEXIBLE).
2442 * In order to avoid unscheduling and scheduling back in everything every
2443 * time an event is added, only do it for the groups of equal priority and
2446 * This can be called after a batch operation on task events, in which case
2447 * event_type is a bit mask of the types of events involved. For CPU events,
2448 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2450 static void ctx_resched(struct perf_cpu_context *cpuctx,
2451 struct perf_event_context *task_ctx,
2452 enum event_type_t event_type)
2454 enum event_type_t ctx_event_type;
2455 bool cpu_event = !!(event_type & EVENT_CPU);
2458 * If pinned groups are involved, flexible groups also need to be
2461 if (event_type & EVENT_PINNED)
2462 event_type |= EVENT_FLEXIBLE;
2464 ctx_event_type = event_type & EVENT_ALL;
2466 perf_pmu_disable(cpuctx->ctx.pmu);
2468 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2471 * Decide which cpu ctx groups to schedule out based on the types
2472 * of events that caused rescheduling:
2473 * - EVENT_CPU: schedule out corresponding groups;
2474 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2475 * - otherwise, do nothing more.
2478 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2479 else if (ctx_event_type & EVENT_PINNED)
2480 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2482 perf_event_sched_in(cpuctx, task_ctx, current);
2483 perf_pmu_enable(cpuctx->ctx.pmu);
2487 * Cross CPU call to install and enable a performance event
2489 * Very similar to remote_function() + event_function() but cannot assume that
2490 * things like ctx->is_active and cpuctx->task_ctx are set.
2492 static int __perf_install_in_context(void *info)
2494 struct perf_event *event = info;
2495 struct perf_event_context *ctx = event->ctx;
2496 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2497 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2498 bool reprogram = true;
2501 raw_spin_lock(&cpuctx->ctx.lock);
2503 raw_spin_lock(&ctx->lock);
2506 reprogram = (ctx->task == current);
2509 * If the task is running, it must be running on this CPU,
2510 * otherwise we cannot reprogram things.
2512 * If its not running, we don't care, ctx->lock will
2513 * serialize against it becoming runnable.
2515 if (task_curr(ctx->task) && !reprogram) {
2520 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2521 } else if (task_ctx) {
2522 raw_spin_lock(&task_ctx->lock);
2525 #ifdef CONFIG_CGROUP_PERF
2526 if (is_cgroup_event(event)) {
2528 * If the current cgroup doesn't match the event's
2529 * cgroup, we should not try to schedule it.
2531 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2532 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2533 event->cgrp->css.cgroup);
2538 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2539 add_event_to_ctx(event, ctx);
2540 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2542 add_event_to_ctx(event, ctx);
2546 perf_ctx_unlock(cpuctx, task_ctx);
2551 static bool exclusive_event_installable(struct perf_event *event,
2552 struct perf_event_context *ctx);
2555 * Attach a performance event to a context.
2557 * Very similar to event_function_call, see comment there.
2560 perf_install_in_context(struct perf_event_context *ctx,
2561 struct perf_event *event,
2564 struct task_struct *task = READ_ONCE(ctx->task);
2566 lockdep_assert_held(&ctx->mutex);
2568 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2570 if (event->cpu != -1)
2574 * Ensures that if we can observe event->ctx, both the event and ctx
2575 * will be 'complete'. See perf_iterate_sb_cpu().
2577 smp_store_release(&event->ctx, ctx);
2580 cpu_function_call(cpu, __perf_install_in_context, event);
2585 * Should not happen, we validate the ctx is still alive before calling.
2587 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2591 * Installing events is tricky because we cannot rely on ctx->is_active
2592 * to be set in case this is the nr_events 0 -> 1 transition.
2594 * Instead we use task_curr(), which tells us if the task is running.
2595 * However, since we use task_curr() outside of rq::lock, we can race
2596 * against the actual state. This means the result can be wrong.
2598 * If we get a false positive, we retry, this is harmless.
2600 * If we get a false negative, things are complicated. If we are after
2601 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2602 * value must be correct. If we're before, it doesn't matter since
2603 * perf_event_context_sched_in() will program the counter.
2605 * However, this hinges on the remote context switch having observed
2606 * our task->perf_event_ctxp[] store, such that it will in fact take
2607 * ctx::lock in perf_event_context_sched_in().
2609 * We do this by task_function_call(), if the IPI fails to hit the task
2610 * we know any future context switch of task must see the
2611 * perf_event_ctpx[] store.
2615 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2616 * task_cpu() load, such that if the IPI then does not find the task
2617 * running, a future context switch of that task must observe the
2622 if (!task_function_call(task, __perf_install_in_context, event))
2625 raw_spin_lock_irq(&ctx->lock);
2627 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2629 * Cannot happen because we already checked above (which also
2630 * cannot happen), and we hold ctx->mutex, which serializes us
2631 * against perf_event_exit_task_context().
2633 raw_spin_unlock_irq(&ctx->lock);
2637 * If the task is not running, ctx->lock will avoid it becoming so,
2638 * thus we can safely install the event.
2640 if (task_curr(task)) {
2641 raw_spin_unlock_irq(&ctx->lock);
2644 add_event_to_ctx(event, ctx);
2645 raw_spin_unlock_irq(&ctx->lock);
2649 * Cross CPU call to enable a performance event
2651 static void __perf_event_enable(struct perf_event *event,
2652 struct perf_cpu_context *cpuctx,
2653 struct perf_event_context *ctx,
2656 struct perf_event *leader = event->group_leader;
2657 struct perf_event_context *task_ctx;
2659 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2660 event->state <= PERF_EVENT_STATE_ERROR)
2664 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2666 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2668 if (!ctx->is_active)
2671 if (!event_filter_match(event)) {
2672 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2677 * If the event is in a group and isn't the group leader,
2678 * then don't put it on unless the group is on.
2680 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2681 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2685 task_ctx = cpuctx->task_ctx;
2687 WARN_ON_ONCE(task_ctx != ctx);
2689 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2695 * If event->ctx is a cloned context, callers must make sure that
2696 * every task struct that event->ctx->task could possibly point to
2697 * remains valid. This condition is satisfied when called through
2698 * perf_event_for_each_child or perf_event_for_each as described
2699 * for perf_event_disable.
2701 static void _perf_event_enable(struct perf_event *event)
2703 struct perf_event_context *ctx = event->ctx;
2705 raw_spin_lock_irq(&ctx->lock);
2706 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2707 event->state < PERF_EVENT_STATE_ERROR) {
2708 raw_spin_unlock_irq(&ctx->lock);
2713 * If the event is in error state, clear that first.
2715 * That way, if we see the event in error state below, we know that it
2716 * has gone back into error state, as distinct from the task having
2717 * been scheduled away before the cross-call arrived.
2719 if (event->state == PERF_EVENT_STATE_ERROR)
2720 event->state = PERF_EVENT_STATE_OFF;
2721 raw_spin_unlock_irq(&ctx->lock);
2723 event_function_call(event, __perf_event_enable, NULL);
2727 * See perf_event_disable();
2729 void perf_event_enable(struct perf_event *event)
2731 struct perf_event_context *ctx;
2733 ctx = perf_event_ctx_lock(event);
2734 _perf_event_enable(event);
2735 perf_event_ctx_unlock(event, ctx);
2737 EXPORT_SYMBOL_GPL(perf_event_enable);
2739 struct stop_event_data {
2740 struct perf_event *event;
2741 unsigned int restart;
2744 static int __perf_event_stop(void *info)
2746 struct stop_event_data *sd = info;
2747 struct perf_event *event = sd->event;
2749 /* if it's already INACTIVE, do nothing */
2750 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2753 /* matches smp_wmb() in event_sched_in() */
2757 * There is a window with interrupts enabled before we get here,
2758 * so we need to check again lest we try to stop another CPU's event.
2760 if (READ_ONCE(event->oncpu) != smp_processor_id())
2763 event->pmu->stop(event, PERF_EF_UPDATE);
2766 * May race with the actual stop (through perf_pmu_output_stop()),
2767 * but it is only used for events with AUX ring buffer, and such
2768 * events will refuse to restart because of rb::aux_mmap_count==0,
2769 * see comments in perf_aux_output_begin().
2771 * Since this is happening on an event-local CPU, no trace is lost
2775 event->pmu->start(event, 0);
2780 static int perf_event_stop(struct perf_event *event, int restart)
2782 struct stop_event_data sd = {
2789 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2792 /* matches smp_wmb() in event_sched_in() */
2796 * We only want to restart ACTIVE events, so if the event goes
2797 * inactive here (event->oncpu==-1), there's nothing more to do;
2798 * fall through with ret==-ENXIO.
2800 ret = cpu_function_call(READ_ONCE(event->oncpu),
2801 __perf_event_stop, &sd);
2802 } while (ret == -EAGAIN);
2808 * In order to contain the amount of racy and tricky in the address filter
2809 * configuration management, it is a two part process:
2811 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2812 * we update the addresses of corresponding vmas in
2813 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2814 * (p2) when an event is scheduled in (pmu::add), it calls
2815 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2816 * if the generation has changed since the previous call.
2818 * If (p1) happens while the event is active, we restart it to force (p2).
2820 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2821 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2823 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2824 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2826 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2829 void perf_event_addr_filters_sync(struct perf_event *event)
2831 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2833 if (!has_addr_filter(event))
2836 raw_spin_lock(&ifh->lock);
2837 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2838 event->pmu->addr_filters_sync(event);
2839 event->hw.addr_filters_gen = event->addr_filters_gen;
2841 raw_spin_unlock(&ifh->lock);
2843 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2845 static int _perf_event_refresh(struct perf_event *event, int refresh)
2848 * not supported on inherited events
2850 if (event->attr.inherit || !is_sampling_event(event))
2853 atomic_add(refresh, &event->event_limit);
2854 _perf_event_enable(event);
2860 * See perf_event_disable()
2862 int perf_event_refresh(struct perf_event *event, int refresh)
2864 struct perf_event_context *ctx;
2867 ctx = perf_event_ctx_lock(event);
2868 ret = _perf_event_refresh(event, refresh);
2869 perf_event_ctx_unlock(event, ctx);
2873 EXPORT_SYMBOL_GPL(perf_event_refresh);
2875 static int perf_event_modify_breakpoint(struct perf_event *bp,
2876 struct perf_event_attr *attr)
2880 _perf_event_disable(bp);
2882 err = modify_user_hw_breakpoint_check(bp, attr, true);
2884 if (!bp->attr.disabled)
2885 _perf_event_enable(bp);
2890 static int perf_event_modify_attr(struct perf_event *event,
2891 struct perf_event_attr *attr)
2893 if (event->attr.type != attr->type)
2896 switch (event->attr.type) {
2897 case PERF_TYPE_BREAKPOINT:
2898 return perf_event_modify_breakpoint(event, attr);
2900 /* Place holder for future additions. */
2905 static void ctx_sched_out(struct perf_event_context *ctx,
2906 struct perf_cpu_context *cpuctx,
2907 enum event_type_t event_type)
2909 struct perf_event *event, *tmp;
2910 int is_active = ctx->is_active;
2912 lockdep_assert_held(&ctx->lock);
2914 if (likely(!ctx->nr_events)) {
2916 * See __perf_remove_from_context().
2918 WARN_ON_ONCE(ctx->is_active);
2920 WARN_ON_ONCE(cpuctx->task_ctx);
2924 ctx->is_active &= ~event_type;
2925 if (!(ctx->is_active & EVENT_ALL))
2929 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2930 if (!ctx->is_active)
2931 cpuctx->task_ctx = NULL;
2935 * Always update time if it was set; not only when it changes.
2936 * Otherwise we can 'forget' to update time for any but the last
2937 * context we sched out. For example:
2939 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2940 * ctx_sched_out(.event_type = EVENT_PINNED)
2942 * would only update time for the pinned events.
2944 if (is_active & EVENT_TIME) {
2945 /* update (and stop) ctx time */
2946 update_context_time(ctx);
2947 update_cgrp_time_from_cpuctx(cpuctx);
2950 is_active ^= ctx->is_active; /* changed bits */
2952 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2956 * If we had been multiplexing, no rotations are necessary, now no events
2959 ctx->rotate_necessary = 0;
2961 perf_pmu_disable(ctx->pmu);
2962 if (is_active & EVENT_PINNED) {
2963 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2964 group_sched_out(event, cpuctx, ctx);
2967 if (is_active & EVENT_FLEXIBLE) {
2968 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2969 group_sched_out(event, cpuctx, ctx);
2971 perf_pmu_enable(ctx->pmu);
2975 * Test whether two contexts are equivalent, i.e. whether they have both been
2976 * cloned from the same version of the same context.
2978 * Equivalence is measured using a generation number in the context that is
2979 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2980 * and list_del_event().
2982 static int context_equiv(struct perf_event_context *ctx1,
2983 struct perf_event_context *ctx2)
2985 lockdep_assert_held(&ctx1->lock);
2986 lockdep_assert_held(&ctx2->lock);
2988 /* Pinning disables the swap optimization */
2989 if (ctx1->pin_count || ctx2->pin_count)
2992 /* If ctx1 is the parent of ctx2 */
2993 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2996 /* If ctx2 is the parent of ctx1 */
2997 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3001 * If ctx1 and ctx2 have the same parent; we flatten the parent
3002 * hierarchy, see perf_event_init_context().
3004 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3005 ctx1->parent_gen == ctx2->parent_gen)
3012 static void __perf_event_sync_stat(struct perf_event *event,
3013 struct perf_event *next_event)
3017 if (!event->attr.inherit_stat)
3021 * Update the event value, we cannot use perf_event_read()
3022 * because we're in the middle of a context switch and have IRQs
3023 * disabled, which upsets smp_call_function_single(), however
3024 * we know the event must be on the current CPU, therefore we
3025 * don't need to use it.
3027 if (event->state == PERF_EVENT_STATE_ACTIVE)
3028 event->pmu->read(event);
3030 perf_event_update_time(event);
3033 * In order to keep per-task stats reliable we need to flip the event
3034 * values when we flip the contexts.
3036 value = local64_read(&next_event->count);
3037 value = local64_xchg(&event->count, value);
3038 local64_set(&next_event->count, value);
3040 swap(event->total_time_enabled, next_event->total_time_enabled);
3041 swap(event->total_time_running, next_event->total_time_running);
3044 * Since we swizzled the values, update the user visible data too.
3046 perf_event_update_userpage(event);
3047 perf_event_update_userpage(next_event);
3050 static void perf_event_sync_stat(struct perf_event_context *ctx,
3051 struct perf_event_context *next_ctx)
3053 struct perf_event *event, *next_event;
3058 update_context_time(ctx);
3060 event = list_first_entry(&ctx->event_list,
3061 struct perf_event, event_entry);
3063 next_event = list_first_entry(&next_ctx->event_list,
3064 struct perf_event, event_entry);
3066 while (&event->event_entry != &ctx->event_list &&
3067 &next_event->event_entry != &next_ctx->event_list) {
3069 __perf_event_sync_stat(event, next_event);
3071 event = list_next_entry(event, event_entry);
3072 next_event = list_next_entry(next_event, event_entry);
3076 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3077 struct task_struct *next)
3079 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3080 struct perf_event_context *next_ctx;
3081 struct perf_event_context *parent, *next_parent;
3082 struct perf_cpu_context *cpuctx;
3088 cpuctx = __get_cpu_context(ctx);
3089 if (!cpuctx->task_ctx)
3093 next_ctx = next->perf_event_ctxp[ctxn];
3097 parent = rcu_dereference(ctx->parent_ctx);
3098 next_parent = rcu_dereference(next_ctx->parent_ctx);
3100 /* If neither context have a parent context; they cannot be clones. */
3101 if (!parent && !next_parent)
3104 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3106 * Looks like the two contexts are clones, so we might be
3107 * able to optimize the context switch. We lock both
3108 * contexts and check that they are clones under the
3109 * lock (including re-checking that neither has been
3110 * uncloned in the meantime). It doesn't matter which
3111 * order we take the locks because no other cpu could
3112 * be trying to lock both of these tasks.
3114 raw_spin_lock(&ctx->lock);
3115 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3116 if (context_equiv(ctx, next_ctx)) {
3117 WRITE_ONCE(ctx->task, next);
3118 WRITE_ONCE(next_ctx->task, task);
3120 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3123 * RCU_INIT_POINTER here is safe because we've not
3124 * modified the ctx and the above modification of
3125 * ctx->task and ctx->task_ctx_data are immaterial
3126 * since those values are always verified under
3127 * ctx->lock which we're now holding.
3129 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3130 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3134 perf_event_sync_stat(ctx, next_ctx);
3136 raw_spin_unlock(&next_ctx->lock);
3137 raw_spin_unlock(&ctx->lock);
3143 raw_spin_lock(&ctx->lock);
3144 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3145 raw_spin_unlock(&ctx->lock);
3149 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3151 void perf_sched_cb_dec(struct pmu *pmu)
3153 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3155 this_cpu_dec(perf_sched_cb_usages);
3157 if (!--cpuctx->sched_cb_usage)
3158 list_del(&cpuctx->sched_cb_entry);
3162 void perf_sched_cb_inc(struct pmu *pmu)
3164 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3166 if (!cpuctx->sched_cb_usage++)
3167 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3169 this_cpu_inc(perf_sched_cb_usages);
3173 * This function provides the context switch callback to the lower code
3174 * layer. It is invoked ONLY when the context switch callback is enabled.
3176 * This callback is relevant even to per-cpu events; for example multi event
3177 * PEBS requires this to provide PID/TID information. This requires we flush
3178 * all queued PEBS records before we context switch to a new task.
3180 static void perf_pmu_sched_task(struct task_struct *prev,
3181 struct task_struct *next,
3184 struct perf_cpu_context *cpuctx;
3190 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3191 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3193 if (WARN_ON_ONCE(!pmu->sched_task))
3196 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3197 perf_pmu_disable(pmu);
3199 pmu->sched_task(cpuctx->task_ctx, sched_in);
3201 perf_pmu_enable(pmu);
3202 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3206 static void perf_event_switch(struct task_struct *task,
3207 struct task_struct *next_prev, bool sched_in);
3209 #define for_each_task_context_nr(ctxn) \
3210 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3213 * Called from scheduler to remove the events of the current task,
3214 * with interrupts disabled.
3216 * We stop each event and update the event value in event->count.
3218 * This does not protect us against NMI, but disable()
3219 * sets the disabled bit in the control field of event _before_
3220 * accessing the event control register. If a NMI hits, then it will
3221 * not restart the event.
3223 void __perf_event_task_sched_out(struct task_struct *task,
3224 struct task_struct *next)
3228 if (__this_cpu_read(perf_sched_cb_usages))
3229 perf_pmu_sched_task(task, next, false);
3231 if (atomic_read(&nr_switch_events))
3232 perf_event_switch(task, next, false);
3234 for_each_task_context_nr(ctxn)
3235 perf_event_context_sched_out(task, ctxn, next);
3238 * if cgroup events exist on this CPU, then we need
3239 * to check if we have to switch out PMU state.
3240 * cgroup event are system-wide mode only
3242 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3243 perf_cgroup_sched_out(task, next);
3247 * Called with IRQs disabled
3249 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3250 enum event_type_t event_type)
3252 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3255 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3256 int (*func)(struct perf_event *, void *), void *data)
3258 struct perf_event **evt, *evt1, *evt2;
3261 evt1 = perf_event_groups_first(groups, -1);
3262 evt2 = perf_event_groups_first(groups, cpu);
3264 while (evt1 || evt2) {
3266 if (evt1->group_index < evt2->group_index)
3276 ret = func(*evt, data);
3280 *evt = perf_event_groups_next(*evt);
3286 struct sched_in_data {
3287 struct perf_event_context *ctx;
3288 struct perf_cpu_context *cpuctx;
3292 static int pinned_sched_in(struct perf_event *event, void *data)
3294 struct sched_in_data *sid = data;
3296 if (event->state <= PERF_EVENT_STATE_OFF)
3299 if (!event_filter_match(event))
3302 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3303 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3304 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3308 * If this pinned group hasn't been scheduled,
3309 * put it in error state.
3311 if (event->state == PERF_EVENT_STATE_INACTIVE)
3312 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3317 static int flexible_sched_in(struct perf_event *event, void *data)
3319 struct sched_in_data *sid = data;
3321 if (event->state <= PERF_EVENT_STATE_OFF)
3324 if (!event_filter_match(event))
3327 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3328 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3330 sid->can_add_hw = 0;
3331 sid->ctx->rotate_necessary = 1;
3334 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3341 ctx_pinned_sched_in(struct perf_event_context *ctx,
3342 struct perf_cpu_context *cpuctx)
3344 struct sched_in_data sid = {
3350 visit_groups_merge(&ctx->pinned_groups,
3352 pinned_sched_in, &sid);
3356 ctx_flexible_sched_in(struct perf_event_context *ctx,
3357 struct perf_cpu_context *cpuctx)
3359 struct sched_in_data sid = {
3365 visit_groups_merge(&ctx->flexible_groups,
3367 flexible_sched_in, &sid);
3371 ctx_sched_in(struct perf_event_context *ctx,
3372 struct perf_cpu_context *cpuctx,
3373 enum event_type_t event_type,
3374 struct task_struct *task)
3376 int is_active = ctx->is_active;
3379 lockdep_assert_held(&ctx->lock);
3381 if (likely(!ctx->nr_events))
3384 ctx->is_active |= (event_type | EVENT_TIME);
3387 cpuctx->task_ctx = ctx;
3389 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3392 is_active ^= ctx->is_active; /* changed bits */
3394 if (is_active & EVENT_TIME) {
3395 /* start ctx time */
3397 ctx->timestamp = now;
3398 perf_cgroup_set_timestamp(task, ctx);
3402 * First go through the list and put on any pinned groups
3403 * in order to give them the best chance of going on.
3405 if (is_active & EVENT_PINNED)
3406 ctx_pinned_sched_in(ctx, cpuctx);
3408 /* Then walk through the lower prio flexible groups */
3409 if (is_active & EVENT_FLEXIBLE)
3410 ctx_flexible_sched_in(ctx, cpuctx);
3413 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3414 enum event_type_t event_type,
3415 struct task_struct *task)
3417 struct perf_event_context *ctx = &cpuctx->ctx;
3419 ctx_sched_in(ctx, cpuctx, event_type, task);
3422 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3423 struct task_struct *task)
3425 struct perf_cpu_context *cpuctx;
3427 cpuctx = __get_cpu_context(ctx);
3428 if (cpuctx->task_ctx == ctx)
3431 perf_ctx_lock(cpuctx, ctx);
3433 * We must check ctx->nr_events while holding ctx->lock, such
3434 * that we serialize against perf_install_in_context().
3436 if (!ctx->nr_events)
3439 perf_pmu_disable(ctx->pmu);
3441 * We want to keep the following priority order:
3442 * cpu pinned (that don't need to move), task pinned,
3443 * cpu flexible, task flexible.
3445 * However, if task's ctx is not carrying any pinned
3446 * events, no need to flip the cpuctx's events around.
3448 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3449 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3450 perf_event_sched_in(cpuctx, ctx, task);
3451 perf_pmu_enable(ctx->pmu);
3454 perf_ctx_unlock(cpuctx, ctx);
3458 * Called from scheduler to add the events of the current task
3459 * with interrupts disabled.
3461 * We restore the event value and then enable it.
3463 * This does not protect us against NMI, but enable()
3464 * sets the enabled bit in the control field of event _before_
3465 * accessing the event control register. If a NMI hits, then it will
3466 * keep the event running.
3468 void __perf_event_task_sched_in(struct task_struct *prev,
3469 struct task_struct *task)
3471 struct perf_event_context *ctx;
3475 * If cgroup events exist on this CPU, then we need to check if we have
3476 * to switch in PMU state; cgroup event are system-wide mode only.
3478 * Since cgroup events are CPU events, we must schedule these in before
3479 * we schedule in the task events.
3481 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3482 perf_cgroup_sched_in(prev, task);
3484 for_each_task_context_nr(ctxn) {
3485 ctx = task->perf_event_ctxp[ctxn];
3489 perf_event_context_sched_in(ctx, task);
3492 if (atomic_read(&nr_switch_events))
3493 perf_event_switch(task, prev, true);
3495 if (__this_cpu_read(perf_sched_cb_usages))
3496 perf_pmu_sched_task(prev, task, true);
3499 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3501 u64 frequency = event->attr.sample_freq;
3502 u64 sec = NSEC_PER_SEC;
3503 u64 divisor, dividend;
3505 int count_fls, nsec_fls, frequency_fls, sec_fls;
3507 count_fls = fls64(count);
3508 nsec_fls = fls64(nsec);
3509 frequency_fls = fls64(frequency);
3513 * We got @count in @nsec, with a target of sample_freq HZ
3514 * the target period becomes:
3517 * period = -------------------
3518 * @nsec * sample_freq
3523 * Reduce accuracy by one bit such that @a and @b converge
3524 * to a similar magnitude.
3526 #define REDUCE_FLS(a, b) \
3528 if (a##_fls > b##_fls) { \
3538 * Reduce accuracy until either term fits in a u64, then proceed with
3539 * the other, so that finally we can do a u64/u64 division.
3541 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3542 REDUCE_FLS(nsec, frequency);
3543 REDUCE_FLS(sec, count);
3546 if (count_fls + sec_fls > 64) {
3547 divisor = nsec * frequency;
3549 while (count_fls + sec_fls > 64) {
3550 REDUCE_FLS(count, sec);
3554 dividend = count * sec;
3556 dividend = count * sec;
3558 while (nsec_fls + frequency_fls > 64) {
3559 REDUCE_FLS(nsec, frequency);
3563 divisor = nsec * frequency;
3569 return div64_u64(dividend, divisor);
3572 static DEFINE_PER_CPU(int, perf_throttled_count);
3573 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3575 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3577 struct hw_perf_event *hwc = &event->hw;
3578 s64 period, sample_period;
3581 period = perf_calculate_period(event, nsec, count);
3583 delta = (s64)(period - hwc->sample_period);
3584 delta = (delta + 7) / 8; /* low pass filter */
3586 sample_period = hwc->sample_period + delta;
3591 hwc->sample_period = sample_period;
3593 if (local64_read(&hwc->period_left) > 8*sample_period) {
3595 event->pmu->stop(event, PERF_EF_UPDATE);
3597 local64_set(&hwc->period_left, 0);
3600 event->pmu->start(event, PERF_EF_RELOAD);
3605 * combine freq adjustment with unthrottling to avoid two passes over the
3606 * events. At the same time, make sure, having freq events does not change
3607 * the rate of unthrottling as that would introduce bias.
3609 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3612 struct perf_event *event;
3613 struct hw_perf_event *hwc;
3614 u64 now, period = TICK_NSEC;
3618 * only need to iterate over all events iff:
3619 * - context have events in frequency mode (needs freq adjust)
3620 * - there are events to unthrottle on this cpu
3622 if (!(ctx->nr_freq || needs_unthr))
3625 raw_spin_lock(&ctx->lock);
3626 perf_pmu_disable(ctx->pmu);
3628 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3629 if (event->state != PERF_EVENT_STATE_ACTIVE)
3632 if (!event_filter_match(event))
3635 perf_pmu_disable(event->pmu);
3639 if (hwc->interrupts == MAX_INTERRUPTS) {
3640 hwc->interrupts = 0;
3641 perf_log_throttle(event, 1);
3642 event->pmu->start(event, 0);
3645 if (!event->attr.freq || !event->attr.sample_freq)
3649 * stop the event and update event->count
3651 event->pmu->stop(event, PERF_EF_UPDATE);
3653 now = local64_read(&event->count);
3654 delta = now - hwc->freq_count_stamp;
3655 hwc->freq_count_stamp = now;
3659 * reload only if value has changed
3660 * we have stopped the event so tell that
3661 * to perf_adjust_period() to avoid stopping it
3665 perf_adjust_period(event, period, delta, false);
3667 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3669 perf_pmu_enable(event->pmu);
3672 perf_pmu_enable(ctx->pmu);
3673 raw_spin_unlock(&ctx->lock);
3677 * Move @event to the tail of the @ctx's elegible events.
3679 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3682 * Rotate the first entry last of non-pinned groups. Rotation might be
3683 * disabled by the inheritance code.
3685 if (ctx->rotate_disable)
3688 perf_event_groups_delete(&ctx->flexible_groups, event);
3689 perf_event_groups_insert(&ctx->flexible_groups, event);
3692 static inline struct perf_event *
3693 ctx_first_active(struct perf_event_context *ctx)
3695 return list_first_entry_or_null(&ctx->flexible_active,
3696 struct perf_event, active_list);
3699 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3701 struct perf_event *cpu_event = NULL, *task_event = NULL;
3702 struct perf_event_context *task_ctx = NULL;
3703 int cpu_rotate, task_rotate;
3706 * Since we run this from IRQ context, nobody can install new
3707 * events, thus the event count values are stable.
3710 cpu_rotate = cpuctx->ctx.rotate_necessary;
3711 task_ctx = cpuctx->task_ctx;
3712 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3714 if (!(cpu_rotate || task_rotate))
3717 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3718 perf_pmu_disable(cpuctx->ctx.pmu);
3721 task_event = ctx_first_active(task_ctx);
3723 cpu_event = ctx_first_active(&cpuctx->ctx);
3726 * As per the order given at ctx_resched() first 'pop' task flexible
3727 * and then, if needed CPU flexible.
3729 if (task_event || (task_ctx && cpu_event))
3730 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3732 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3735 rotate_ctx(task_ctx, task_event);
3737 rotate_ctx(&cpuctx->ctx, cpu_event);
3739 perf_event_sched_in(cpuctx, task_ctx, current);
3741 perf_pmu_enable(cpuctx->ctx.pmu);
3742 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3747 void perf_event_task_tick(void)
3749 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3750 struct perf_event_context *ctx, *tmp;
3753 lockdep_assert_irqs_disabled();
3755 __this_cpu_inc(perf_throttled_seq);
3756 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3757 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3759 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3760 perf_adjust_freq_unthr_context(ctx, throttled);
3763 static int event_enable_on_exec(struct perf_event *event,
3764 struct perf_event_context *ctx)
3766 if (!event->attr.enable_on_exec)
3769 event->attr.enable_on_exec = 0;
3770 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3773 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3779 * Enable all of a task's events that have been marked enable-on-exec.
3780 * This expects task == current.
3782 static void perf_event_enable_on_exec(int ctxn)
3784 struct perf_event_context *ctx, *clone_ctx = NULL;
3785 enum event_type_t event_type = 0;
3786 struct perf_cpu_context *cpuctx;
3787 struct perf_event *event;
3788 unsigned long flags;
3791 local_irq_save(flags);
3792 ctx = current->perf_event_ctxp[ctxn];
3793 if (!ctx || !ctx->nr_events)
3796 cpuctx = __get_cpu_context(ctx);
3797 perf_ctx_lock(cpuctx, ctx);
3798 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3799 list_for_each_entry(event, &ctx->event_list, event_entry) {
3800 enabled |= event_enable_on_exec(event, ctx);
3801 event_type |= get_event_type(event);
3805 * Unclone and reschedule this context if we enabled any event.
3808 clone_ctx = unclone_ctx(ctx);
3809 ctx_resched(cpuctx, ctx, event_type);
3811 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3813 perf_ctx_unlock(cpuctx, ctx);
3816 local_irq_restore(flags);
3822 struct perf_read_data {
3823 struct perf_event *event;
3828 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3830 u16 local_pkg, event_pkg;
3832 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3833 int local_cpu = smp_processor_id();
3835 event_pkg = topology_physical_package_id(event_cpu);
3836 local_pkg = topology_physical_package_id(local_cpu);
3838 if (event_pkg == local_pkg)
3846 * Cross CPU call to read the hardware event
3848 static void __perf_event_read(void *info)
3850 struct perf_read_data *data = info;
3851 struct perf_event *sub, *event = data->event;
3852 struct perf_event_context *ctx = event->ctx;
3853 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3854 struct pmu *pmu = event->pmu;
3857 * If this is a task context, we need to check whether it is
3858 * the current task context of this cpu. If not it has been
3859 * scheduled out before the smp call arrived. In that case
3860 * event->count would have been updated to a recent sample
3861 * when the event was scheduled out.
3863 if (ctx->task && cpuctx->task_ctx != ctx)
3866 raw_spin_lock(&ctx->lock);
3867 if (ctx->is_active & EVENT_TIME) {
3868 update_context_time(ctx);
3869 update_cgrp_time_from_event(event);
3872 perf_event_update_time(event);
3874 perf_event_update_sibling_time(event);
3876 if (event->state != PERF_EVENT_STATE_ACTIVE)
3885 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3889 for_each_sibling_event(sub, event) {
3890 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3892 * Use sibling's PMU rather than @event's since
3893 * sibling could be on different (eg: software) PMU.
3895 sub->pmu->read(sub);
3899 data->ret = pmu->commit_txn(pmu);
3902 raw_spin_unlock(&ctx->lock);
3905 static inline u64 perf_event_count(struct perf_event *event)
3907 return local64_read(&event->count) + atomic64_read(&event->child_count);
3911 * NMI-safe method to read a local event, that is an event that
3913 * - either for the current task, or for this CPU
3914 * - does not have inherit set, for inherited task events
3915 * will not be local and we cannot read them atomically
3916 * - must not have a pmu::count method
3918 int perf_event_read_local(struct perf_event *event, u64 *value,
3919 u64 *enabled, u64 *running)
3921 unsigned long flags;
3925 * Disabling interrupts avoids all counter scheduling (context
3926 * switches, timer based rotation and IPIs).
3928 local_irq_save(flags);
3931 * It must not be an event with inherit set, we cannot read
3932 * all child counters from atomic context.
3934 if (event->attr.inherit) {
3939 /* If this is a per-task event, it must be for current */
3940 if ((event->attach_state & PERF_ATTACH_TASK) &&
3941 event->hw.target != current) {
3946 /* If this is a per-CPU event, it must be for this CPU */
3947 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3948 event->cpu != smp_processor_id()) {
3953 /* If this is a pinned event it must be running on this CPU */
3954 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3960 * If the event is currently on this CPU, its either a per-task event,
3961 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3964 if (event->oncpu == smp_processor_id())
3965 event->pmu->read(event);
3967 *value = local64_read(&event->count);
3968 if (enabled || running) {
3969 u64 now = event->shadow_ctx_time + perf_clock();
3970 u64 __enabled, __running;
3972 __perf_update_times(event, now, &__enabled, &__running);
3974 *enabled = __enabled;
3976 *running = __running;
3979 local_irq_restore(flags);
3984 static int perf_event_read(struct perf_event *event, bool group)
3986 enum perf_event_state state = READ_ONCE(event->state);
3987 int event_cpu, ret = 0;
3990 * If event is enabled and currently active on a CPU, update the
3991 * value in the event structure:
3994 if (state == PERF_EVENT_STATE_ACTIVE) {
3995 struct perf_read_data data;
3998 * Orders the ->state and ->oncpu loads such that if we see
3999 * ACTIVE we must also see the right ->oncpu.
4001 * Matches the smp_wmb() from event_sched_in().
4005 event_cpu = READ_ONCE(event->oncpu);
4006 if ((unsigned)event_cpu >= nr_cpu_ids)
4009 data = (struct perf_read_data){
4016 event_cpu = __perf_event_read_cpu(event, event_cpu);
4019 * Purposely ignore the smp_call_function_single() return
4022 * If event_cpu isn't a valid CPU it means the event got
4023 * scheduled out and that will have updated the event count.
4025 * Therefore, either way, we'll have an up-to-date event count
4028 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4032 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4033 struct perf_event_context *ctx = event->ctx;
4034 unsigned long flags;
4036 raw_spin_lock_irqsave(&ctx->lock, flags);
4037 state = event->state;
4038 if (state != PERF_EVENT_STATE_INACTIVE) {
4039 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4044 * May read while context is not active (e.g., thread is
4045 * blocked), in that case we cannot update context time
4047 if (ctx->is_active & EVENT_TIME) {
4048 update_context_time(ctx);
4049 update_cgrp_time_from_event(event);
4052 perf_event_update_time(event);
4054 perf_event_update_sibling_time(event);
4055 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4062 * Initialize the perf_event context in a task_struct:
4064 static void __perf_event_init_context(struct perf_event_context *ctx)
4066 raw_spin_lock_init(&ctx->lock);
4067 mutex_init(&ctx->mutex);
4068 INIT_LIST_HEAD(&ctx->active_ctx_list);
4069 perf_event_groups_init(&ctx->pinned_groups);
4070 perf_event_groups_init(&ctx->flexible_groups);
4071 INIT_LIST_HEAD(&ctx->event_list);
4072 INIT_LIST_HEAD(&ctx->pinned_active);
4073 INIT_LIST_HEAD(&ctx->flexible_active);
4074 atomic_set(&ctx->refcount, 1);
4077 static struct perf_event_context *
4078 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4080 struct perf_event_context *ctx;
4082 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4086 __perf_event_init_context(ctx);
4089 get_task_struct(task);
4096 static struct task_struct *
4097 find_lively_task_by_vpid(pid_t vpid)
4099 struct task_struct *task;
4105 task = find_task_by_vpid(vpid);
4107 get_task_struct(task);
4111 return ERR_PTR(-ESRCH);
4117 * Returns a matching context with refcount and pincount.
4119 static struct perf_event_context *
4120 find_get_context(struct pmu *pmu, struct task_struct *task,
4121 struct perf_event *event)
4123 struct perf_event_context *ctx, *clone_ctx = NULL;
4124 struct perf_cpu_context *cpuctx;
4125 void *task_ctx_data = NULL;
4126 unsigned long flags;
4128 int cpu = event->cpu;
4131 /* Must be root to operate on a CPU event: */
4132 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4133 return ERR_PTR(-EACCES);
4135 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4144 ctxn = pmu->task_ctx_nr;
4148 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4149 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4150 if (!task_ctx_data) {
4157 ctx = perf_lock_task_context(task, ctxn, &flags);
4159 clone_ctx = unclone_ctx(ctx);
4162 if (task_ctx_data && !ctx->task_ctx_data) {
4163 ctx->task_ctx_data = task_ctx_data;
4164 task_ctx_data = NULL;
4166 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4171 ctx = alloc_perf_context(pmu, task);
4176 if (task_ctx_data) {
4177 ctx->task_ctx_data = task_ctx_data;
4178 task_ctx_data = NULL;
4182 mutex_lock(&task->perf_event_mutex);
4184 * If it has already passed perf_event_exit_task().
4185 * we must see PF_EXITING, it takes this mutex too.
4187 if (task->flags & PF_EXITING)
4189 else if (task->perf_event_ctxp[ctxn])
4194 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4196 mutex_unlock(&task->perf_event_mutex);
4198 if (unlikely(err)) {
4207 kfree(task_ctx_data);
4211 kfree(task_ctx_data);
4212 return ERR_PTR(err);
4215 static void perf_event_free_filter(struct perf_event *event);
4216 static void perf_event_free_bpf_prog(struct perf_event *event);
4218 static void free_event_rcu(struct rcu_head *head)
4220 struct perf_event *event;
4222 event = container_of(head, struct perf_event, rcu_head);
4224 put_pid_ns(event->ns);
4225 perf_event_free_filter(event);
4229 static void ring_buffer_attach(struct perf_event *event,
4230 struct ring_buffer *rb);
4232 static void detach_sb_event(struct perf_event *event)
4234 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4236 raw_spin_lock(&pel->lock);
4237 list_del_rcu(&event->sb_list);
4238 raw_spin_unlock(&pel->lock);
4241 static bool is_sb_event(struct perf_event *event)
4243 struct perf_event_attr *attr = &event->attr;
4248 if (event->attach_state & PERF_ATTACH_TASK)
4251 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4252 attr->comm || attr->comm_exec ||
4254 attr->context_switch)
4259 static void unaccount_pmu_sb_event(struct perf_event *event)
4261 if (is_sb_event(event))
4262 detach_sb_event(event);
4265 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4270 if (is_cgroup_event(event))
4271 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4274 #ifdef CONFIG_NO_HZ_FULL
4275 static DEFINE_SPINLOCK(nr_freq_lock);
4278 static void unaccount_freq_event_nohz(void)
4280 #ifdef CONFIG_NO_HZ_FULL
4281 spin_lock(&nr_freq_lock);
4282 if (atomic_dec_and_test(&nr_freq_events))
4283 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4284 spin_unlock(&nr_freq_lock);
4288 static void unaccount_freq_event(void)
4290 if (tick_nohz_full_enabled())
4291 unaccount_freq_event_nohz();
4293 atomic_dec(&nr_freq_events);
4296 static void unaccount_event(struct perf_event *event)
4303 if (event->attach_state & PERF_ATTACH_TASK)
4305 if (event->attr.mmap || event->attr.mmap_data)
4306 atomic_dec(&nr_mmap_events);
4307 if (event->attr.comm)
4308 atomic_dec(&nr_comm_events);
4309 if (event->attr.namespaces)
4310 atomic_dec(&nr_namespaces_events);
4311 if (event->attr.task)
4312 atomic_dec(&nr_task_events);
4313 if (event->attr.freq)
4314 unaccount_freq_event();
4315 if (event->attr.context_switch) {
4317 atomic_dec(&nr_switch_events);
4319 if (is_cgroup_event(event))
4321 if (has_branch_stack(event))
4325 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4326 schedule_delayed_work(&perf_sched_work, HZ);
4329 unaccount_event_cpu(event, event->cpu);
4331 unaccount_pmu_sb_event(event);
4334 static void perf_sched_delayed(struct work_struct *work)
4336 mutex_lock(&perf_sched_mutex);
4337 if (atomic_dec_and_test(&perf_sched_count))
4338 static_branch_disable(&perf_sched_events);
4339 mutex_unlock(&perf_sched_mutex);
4343 * The following implement mutual exclusion of events on "exclusive" pmus
4344 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4345 * at a time, so we disallow creating events that might conflict, namely:
4347 * 1) cpu-wide events in the presence of per-task events,
4348 * 2) per-task events in the presence of cpu-wide events,
4349 * 3) two matching events on the same context.
4351 * The former two cases are handled in the allocation path (perf_event_alloc(),
4352 * _free_event()), the latter -- before the first perf_install_in_context().
4354 static int exclusive_event_init(struct perf_event *event)
4356 struct pmu *pmu = event->pmu;
4358 if (!is_exclusive_pmu(pmu))
4362 * Prevent co-existence of per-task and cpu-wide events on the
4363 * same exclusive pmu.
4365 * Negative pmu::exclusive_cnt means there are cpu-wide
4366 * events on this "exclusive" pmu, positive means there are
4369 * Since this is called in perf_event_alloc() path, event::ctx
4370 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4371 * to mean "per-task event", because unlike other attach states it
4372 * never gets cleared.
4374 if (event->attach_state & PERF_ATTACH_TASK) {
4375 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4378 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4385 static void exclusive_event_destroy(struct perf_event *event)
4387 struct pmu *pmu = event->pmu;
4389 if (!is_exclusive_pmu(pmu))
4392 /* see comment in exclusive_event_init() */
4393 if (event->attach_state & PERF_ATTACH_TASK)
4394 atomic_dec(&pmu->exclusive_cnt);
4396 atomic_inc(&pmu->exclusive_cnt);
4399 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4401 if ((e1->pmu == e2->pmu) &&
4402 (e1->cpu == e2->cpu ||
4409 static bool exclusive_event_installable(struct perf_event *event,
4410 struct perf_event_context *ctx)
4412 struct perf_event *iter_event;
4413 struct pmu *pmu = event->pmu;
4415 lockdep_assert_held(&ctx->mutex);
4417 if (!is_exclusive_pmu(pmu))
4420 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4421 if (exclusive_event_match(iter_event, event))
4428 static void perf_addr_filters_splice(struct perf_event *event,
4429 struct list_head *head);
4431 static void _free_event(struct perf_event *event)
4433 irq_work_sync(&event->pending);
4435 unaccount_event(event);
4439 * Can happen when we close an event with re-directed output.
4441 * Since we have a 0 refcount, perf_mmap_close() will skip
4442 * over us; possibly making our ring_buffer_put() the last.
4444 mutex_lock(&event->mmap_mutex);
4445 ring_buffer_attach(event, NULL);
4446 mutex_unlock(&event->mmap_mutex);
4449 if (is_cgroup_event(event))
4450 perf_detach_cgroup(event);
4452 if (!event->parent) {
4453 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4454 put_callchain_buffers();
4457 perf_event_free_bpf_prog(event);
4458 perf_addr_filters_splice(event, NULL);
4459 kfree(event->addr_filter_ranges);
4462 event->destroy(event);
4465 * Must be after ->destroy(), due to uprobe_perf_close() using
4468 if (event->hw.target)
4469 put_task_struct(event->hw.target);
4472 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4473 * all task references must be cleaned up.
4476 put_ctx(event->ctx);
4478 exclusive_event_destroy(event);
4479 module_put(event->pmu->module);
4481 call_rcu(&event->rcu_head, free_event_rcu);
4485 * Used to free events which have a known refcount of 1, such as in error paths
4486 * where the event isn't exposed yet and inherited events.
4488 static void free_event(struct perf_event *event)
4490 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4491 "unexpected event refcount: %ld; ptr=%p\n",
4492 atomic_long_read(&event->refcount), event)) {
4493 /* leak to avoid use-after-free */
4501 * Remove user event from the owner task.
4503 static void perf_remove_from_owner(struct perf_event *event)
4505 struct task_struct *owner;
4509 * Matches the smp_store_release() in perf_event_exit_task(). If we
4510 * observe !owner it means the list deletion is complete and we can
4511 * indeed free this event, otherwise we need to serialize on
4512 * owner->perf_event_mutex.
4514 owner = READ_ONCE(event->owner);
4517 * Since delayed_put_task_struct() also drops the last
4518 * task reference we can safely take a new reference
4519 * while holding the rcu_read_lock().
4521 get_task_struct(owner);
4527 * If we're here through perf_event_exit_task() we're already
4528 * holding ctx->mutex which would be an inversion wrt. the
4529 * normal lock order.
4531 * However we can safely take this lock because its the child
4534 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4537 * We have to re-check the event->owner field, if it is cleared
4538 * we raced with perf_event_exit_task(), acquiring the mutex
4539 * ensured they're done, and we can proceed with freeing the
4543 list_del_init(&event->owner_entry);
4544 smp_store_release(&event->owner, NULL);
4546 mutex_unlock(&owner->perf_event_mutex);
4547 put_task_struct(owner);
4551 static void put_event(struct perf_event *event)
4553 if (!atomic_long_dec_and_test(&event->refcount))
4560 * Kill an event dead; while event:refcount will preserve the event
4561 * object, it will not preserve its functionality. Once the last 'user'
4562 * gives up the object, we'll destroy the thing.
4564 int perf_event_release_kernel(struct perf_event *event)
4566 struct perf_event_context *ctx = event->ctx;
4567 struct perf_event *child, *tmp;
4568 LIST_HEAD(free_list);
4571 * If we got here through err_file: fput(event_file); we will not have
4572 * attached to a context yet.
4575 WARN_ON_ONCE(event->attach_state &
4576 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4580 if (!is_kernel_event(event))
4581 perf_remove_from_owner(event);
4583 ctx = perf_event_ctx_lock(event);
4584 WARN_ON_ONCE(ctx->parent_ctx);
4585 perf_remove_from_context(event, DETACH_GROUP);
4587 raw_spin_lock_irq(&ctx->lock);
4589 * Mark this event as STATE_DEAD, there is no external reference to it
4592 * Anybody acquiring event->child_mutex after the below loop _must_
4593 * also see this, most importantly inherit_event() which will avoid
4594 * placing more children on the list.
4596 * Thus this guarantees that we will in fact observe and kill _ALL_
4599 event->state = PERF_EVENT_STATE_DEAD;
4600 raw_spin_unlock_irq(&ctx->lock);
4602 perf_event_ctx_unlock(event, ctx);
4605 mutex_lock(&event->child_mutex);
4606 list_for_each_entry(child, &event->child_list, child_list) {
4609 * Cannot change, child events are not migrated, see the
4610 * comment with perf_event_ctx_lock_nested().
4612 ctx = READ_ONCE(child->ctx);
4614 * Since child_mutex nests inside ctx::mutex, we must jump
4615 * through hoops. We start by grabbing a reference on the ctx.
4617 * Since the event cannot get freed while we hold the
4618 * child_mutex, the context must also exist and have a !0
4624 * Now that we have a ctx ref, we can drop child_mutex, and
4625 * acquire ctx::mutex without fear of it going away. Then we
4626 * can re-acquire child_mutex.
4628 mutex_unlock(&event->child_mutex);
4629 mutex_lock(&ctx->mutex);
4630 mutex_lock(&event->child_mutex);
4633 * Now that we hold ctx::mutex and child_mutex, revalidate our
4634 * state, if child is still the first entry, it didn't get freed
4635 * and we can continue doing so.
4637 tmp = list_first_entry_or_null(&event->child_list,
4638 struct perf_event, child_list);
4640 perf_remove_from_context(child, DETACH_GROUP);
4641 list_move(&child->child_list, &free_list);
4643 * This matches the refcount bump in inherit_event();
4644 * this can't be the last reference.
4649 mutex_unlock(&event->child_mutex);
4650 mutex_unlock(&ctx->mutex);
4654 mutex_unlock(&event->child_mutex);
4656 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4657 void *var = &child->ctx->refcount;
4659 list_del(&child->child_list);
4663 * Wake any perf_event_free_task() waiting for this event to be
4666 smp_mb(); /* pairs with wait_var_event() */
4671 put_event(event); /* Must be the 'last' reference */
4674 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4677 * Called when the last reference to the file is gone.
4679 static int perf_release(struct inode *inode, struct file *file)
4681 perf_event_release_kernel(file->private_data);
4685 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4687 struct perf_event *child;
4693 mutex_lock(&event->child_mutex);
4695 (void)perf_event_read(event, false);
4696 total += perf_event_count(event);
4698 *enabled += event->total_time_enabled +
4699 atomic64_read(&event->child_total_time_enabled);
4700 *running += event->total_time_running +
4701 atomic64_read(&event->child_total_time_running);
4703 list_for_each_entry(child, &event->child_list, child_list) {
4704 (void)perf_event_read(child, false);
4705 total += perf_event_count(child);
4706 *enabled += child->total_time_enabled;
4707 *running += child->total_time_running;
4709 mutex_unlock(&event->child_mutex);
4714 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4716 struct perf_event_context *ctx;
4719 ctx = perf_event_ctx_lock(event);
4720 count = __perf_event_read_value(event, enabled, running);
4721 perf_event_ctx_unlock(event, ctx);
4725 EXPORT_SYMBOL_GPL(perf_event_read_value);
4727 static int __perf_read_group_add(struct perf_event *leader,
4728 u64 read_format, u64 *values)
4730 struct perf_event_context *ctx = leader->ctx;
4731 struct perf_event *sub;
4732 unsigned long flags;
4733 int n = 1; /* skip @nr */
4736 ret = perf_event_read(leader, true);
4740 raw_spin_lock_irqsave(&ctx->lock, flags);
4743 * Since we co-schedule groups, {enabled,running} times of siblings
4744 * will be identical to those of the leader, so we only publish one
4747 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4748 values[n++] += leader->total_time_enabled +
4749 atomic64_read(&leader->child_total_time_enabled);
4752 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4753 values[n++] += leader->total_time_running +
4754 atomic64_read(&leader->child_total_time_running);
4758 * Write {count,id} tuples for every sibling.
4760 values[n++] += perf_event_count(leader);
4761 if (read_format & PERF_FORMAT_ID)
4762 values[n++] = primary_event_id(leader);
4764 for_each_sibling_event(sub, leader) {
4765 values[n++] += perf_event_count(sub);
4766 if (read_format & PERF_FORMAT_ID)
4767 values[n++] = primary_event_id(sub);
4770 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4774 static int perf_read_group(struct perf_event *event,
4775 u64 read_format, char __user *buf)
4777 struct perf_event *leader = event->group_leader, *child;
4778 struct perf_event_context *ctx = leader->ctx;
4782 lockdep_assert_held(&ctx->mutex);
4784 values = kzalloc(event->read_size, GFP_KERNEL);
4788 values[0] = 1 + leader->nr_siblings;
4791 * By locking the child_mutex of the leader we effectively
4792 * lock the child list of all siblings.. XXX explain how.
4794 mutex_lock(&leader->child_mutex);
4796 ret = __perf_read_group_add(leader, read_format, values);
4800 list_for_each_entry(child, &leader->child_list, child_list) {
4801 ret = __perf_read_group_add(child, read_format, values);
4806 mutex_unlock(&leader->child_mutex);
4808 ret = event->read_size;
4809 if (copy_to_user(buf, values, event->read_size))
4814 mutex_unlock(&leader->child_mutex);
4820 static int perf_read_one(struct perf_event *event,
4821 u64 read_format, char __user *buf)
4823 u64 enabled, running;
4827 values[n++] = __perf_event_read_value(event, &enabled, &running);
4828 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4829 values[n++] = enabled;
4830 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4831 values[n++] = running;
4832 if (read_format & PERF_FORMAT_ID)
4833 values[n++] = primary_event_id(event);
4835 if (copy_to_user(buf, values, n * sizeof(u64)))
4838 return n * sizeof(u64);
4841 static bool is_event_hup(struct perf_event *event)
4845 if (event->state > PERF_EVENT_STATE_EXIT)
4848 mutex_lock(&event->child_mutex);
4849 no_children = list_empty(&event->child_list);
4850 mutex_unlock(&event->child_mutex);
4855 * Read the performance event - simple non blocking version for now
4858 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4860 u64 read_format = event->attr.read_format;
4864 * Return end-of-file for a read on an event that is in
4865 * error state (i.e. because it was pinned but it couldn't be
4866 * scheduled on to the CPU at some point).
4868 if (event->state == PERF_EVENT_STATE_ERROR)
4871 if (count < event->read_size)
4874 WARN_ON_ONCE(event->ctx->parent_ctx);
4875 if (read_format & PERF_FORMAT_GROUP)
4876 ret = perf_read_group(event, read_format, buf);
4878 ret = perf_read_one(event, read_format, buf);
4884 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4886 struct perf_event *event = file->private_data;
4887 struct perf_event_context *ctx;
4890 ctx = perf_event_ctx_lock(event);
4891 ret = __perf_read(event, buf, count);
4892 perf_event_ctx_unlock(event, ctx);
4897 static __poll_t perf_poll(struct file *file, poll_table *wait)
4899 struct perf_event *event = file->private_data;
4900 struct ring_buffer *rb;
4901 __poll_t events = EPOLLHUP;
4903 poll_wait(file, &event->waitq, wait);
4905 if (is_event_hup(event))
4909 * Pin the event->rb by taking event->mmap_mutex; otherwise
4910 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4912 mutex_lock(&event->mmap_mutex);
4915 events = atomic_xchg(&rb->poll, 0);
4916 mutex_unlock(&event->mmap_mutex);
4920 static void _perf_event_reset(struct perf_event *event)
4922 (void)perf_event_read(event, false);
4923 local64_set(&event->count, 0);
4924 perf_event_update_userpage(event);
4928 * Holding the top-level event's child_mutex means that any
4929 * descendant process that has inherited this event will block
4930 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4931 * task existence requirements of perf_event_enable/disable.
4933 static void perf_event_for_each_child(struct perf_event *event,
4934 void (*func)(struct perf_event *))
4936 struct perf_event *child;
4938 WARN_ON_ONCE(event->ctx->parent_ctx);
4940 mutex_lock(&event->child_mutex);
4942 list_for_each_entry(child, &event->child_list, child_list)
4944 mutex_unlock(&event->child_mutex);
4947 static void perf_event_for_each(struct perf_event *event,
4948 void (*func)(struct perf_event *))
4950 struct perf_event_context *ctx = event->ctx;
4951 struct perf_event *sibling;
4953 lockdep_assert_held(&ctx->mutex);
4955 event = event->group_leader;
4957 perf_event_for_each_child(event, func);
4958 for_each_sibling_event(sibling, event)
4959 perf_event_for_each_child(sibling, func);
4962 static void __perf_event_period(struct perf_event *event,
4963 struct perf_cpu_context *cpuctx,
4964 struct perf_event_context *ctx,
4967 u64 value = *((u64 *)info);
4970 if (event->attr.freq) {
4971 event->attr.sample_freq = value;
4973 event->attr.sample_period = value;
4974 event->hw.sample_period = value;
4977 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4979 perf_pmu_disable(ctx->pmu);
4981 * We could be throttled; unthrottle now to avoid the tick
4982 * trying to unthrottle while we already re-started the event.
4984 if (event->hw.interrupts == MAX_INTERRUPTS) {
4985 event->hw.interrupts = 0;
4986 perf_log_throttle(event, 1);
4988 event->pmu->stop(event, PERF_EF_UPDATE);
4991 local64_set(&event->hw.period_left, 0);
4994 event->pmu->start(event, PERF_EF_RELOAD);
4995 perf_pmu_enable(ctx->pmu);
4999 static int perf_event_check_period(struct perf_event *event, u64 value)
5001 return event->pmu->check_period(event, value);
5004 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5008 if (!is_sampling_event(event))
5011 if (copy_from_user(&value, arg, sizeof(value)))
5017 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5020 if (perf_event_check_period(event, value))
5023 if (!event->attr.freq && (value & (1ULL << 63)))
5026 event_function_call(event, __perf_event_period, &value);
5031 static const struct file_operations perf_fops;
5033 static inline int perf_fget_light(int fd, struct fd *p)
5035 struct fd f = fdget(fd);
5039 if (f.file->f_op != &perf_fops) {
5047 static int perf_event_set_output(struct perf_event *event,
5048 struct perf_event *output_event);
5049 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5050 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5051 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5052 struct perf_event_attr *attr);
5054 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5056 void (*func)(struct perf_event *);
5060 case PERF_EVENT_IOC_ENABLE:
5061 func = _perf_event_enable;
5063 case PERF_EVENT_IOC_DISABLE:
5064 func = _perf_event_disable;
5066 case PERF_EVENT_IOC_RESET:
5067 func = _perf_event_reset;
5070 case PERF_EVENT_IOC_REFRESH:
5071 return _perf_event_refresh(event, arg);
5073 case PERF_EVENT_IOC_PERIOD:
5074 return perf_event_period(event, (u64 __user *)arg);
5076 case PERF_EVENT_IOC_ID:
5078 u64 id = primary_event_id(event);
5080 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5085 case PERF_EVENT_IOC_SET_OUTPUT:
5089 struct perf_event *output_event;
5091 ret = perf_fget_light(arg, &output);
5094 output_event = output.file->private_data;
5095 ret = perf_event_set_output(event, output_event);
5098 ret = perf_event_set_output(event, NULL);
5103 case PERF_EVENT_IOC_SET_FILTER:
5104 return perf_event_set_filter(event, (void __user *)arg);
5106 case PERF_EVENT_IOC_SET_BPF:
5107 return perf_event_set_bpf_prog(event, arg);
5109 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5110 struct ring_buffer *rb;
5113 rb = rcu_dereference(event->rb);
5114 if (!rb || !rb->nr_pages) {
5118 rb_toggle_paused(rb, !!arg);
5123 case PERF_EVENT_IOC_QUERY_BPF:
5124 return perf_event_query_prog_array(event, (void __user *)arg);
5126 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5127 struct perf_event_attr new_attr;
5128 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5134 return perf_event_modify_attr(event, &new_attr);
5140 if (flags & PERF_IOC_FLAG_GROUP)
5141 perf_event_for_each(event, func);
5143 perf_event_for_each_child(event, func);
5148 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5150 struct perf_event *event = file->private_data;
5151 struct perf_event_context *ctx;
5154 ctx = perf_event_ctx_lock(event);
5155 ret = _perf_ioctl(event, cmd, arg);
5156 perf_event_ctx_unlock(event, ctx);
5161 #ifdef CONFIG_COMPAT
5162 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5165 switch (_IOC_NR(cmd)) {
5166 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5167 case _IOC_NR(PERF_EVENT_IOC_ID):
5168 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5169 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5170 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5171 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5172 cmd &= ~IOCSIZE_MASK;
5173 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5177 return perf_ioctl(file, cmd, arg);
5180 # define perf_compat_ioctl NULL
5183 int perf_event_task_enable(void)
5185 struct perf_event_context *ctx;
5186 struct perf_event *event;
5188 mutex_lock(¤t->perf_event_mutex);
5189 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5190 ctx = perf_event_ctx_lock(event);
5191 perf_event_for_each_child(event, _perf_event_enable);
5192 perf_event_ctx_unlock(event, ctx);
5194 mutex_unlock(¤t->perf_event_mutex);
5199 int perf_event_task_disable(void)
5201 struct perf_event_context *ctx;
5202 struct perf_event *event;
5204 mutex_lock(¤t->perf_event_mutex);
5205 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5206 ctx = perf_event_ctx_lock(event);
5207 perf_event_for_each_child(event, _perf_event_disable);
5208 perf_event_ctx_unlock(event, ctx);
5210 mutex_unlock(¤t->perf_event_mutex);
5215 static int perf_event_index(struct perf_event *event)
5217 if (event->hw.state & PERF_HES_STOPPED)
5220 if (event->state != PERF_EVENT_STATE_ACTIVE)
5223 return event->pmu->event_idx(event);
5226 static void calc_timer_values(struct perf_event *event,
5233 *now = perf_clock();
5234 ctx_time = event->shadow_ctx_time + *now;
5235 __perf_update_times(event, ctx_time, enabled, running);
5238 static void perf_event_init_userpage(struct perf_event *event)
5240 struct perf_event_mmap_page *userpg;
5241 struct ring_buffer *rb;
5244 rb = rcu_dereference(event->rb);
5248 userpg = rb->user_page;
5250 /* Allow new userspace to detect that bit 0 is deprecated */
5251 userpg->cap_bit0_is_deprecated = 1;
5252 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5253 userpg->data_offset = PAGE_SIZE;
5254 userpg->data_size = perf_data_size(rb);
5260 void __weak arch_perf_update_userpage(
5261 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5266 * Callers need to ensure there can be no nesting of this function, otherwise
5267 * the seqlock logic goes bad. We can not serialize this because the arch
5268 * code calls this from NMI context.
5270 void perf_event_update_userpage(struct perf_event *event)
5272 struct perf_event_mmap_page *userpg;
5273 struct ring_buffer *rb;
5274 u64 enabled, running, now;
5277 rb = rcu_dereference(event->rb);
5282 * compute total_time_enabled, total_time_running
5283 * based on snapshot values taken when the event
5284 * was last scheduled in.
5286 * we cannot simply called update_context_time()
5287 * because of locking issue as we can be called in
5290 calc_timer_values(event, &now, &enabled, &running);
5292 userpg = rb->user_page;
5294 * Disable preemption to guarantee consistent time stamps are stored to
5300 userpg->index = perf_event_index(event);
5301 userpg->offset = perf_event_count(event);
5303 userpg->offset -= local64_read(&event->hw.prev_count);
5305 userpg->time_enabled = enabled +
5306 atomic64_read(&event->child_total_time_enabled);
5308 userpg->time_running = running +
5309 atomic64_read(&event->child_total_time_running);
5311 arch_perf_update_userpage(event, userpg, now);
5319 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5321 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5323 struct perf_event *event = vmf->vma->vm_file->private_data;
5324 struct ring_buffer *rb;
5325 vm_fault_t ret = VM_FAULT_SIGBUS;
5327 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5328 if (vmf->pgoff == 0)
5334 rb = rcu_dereference(event->rb);
5338 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5341 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5345 get_page(vmf->page);
5346 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5347 vmf->page->index = vmf->pgoff;
5356 static void ring_buffer_attach(struct perf_event *event,
5357 struct ring_buffer *rb)
5359 struct ring_buffer *old_rb = NULL;
5360 unsigned long flags;
5364 * Should be impossible, we set this when removing
5365 * event->rb_entry and wait/clear when adding event->rb_entry.
5367 WARN_ON_ONCE(event->rcu_pending);
5370 spin_lock_irqsave(&old_rb->event_lock, flags);
5371 list_del_rcu(&event->rb_entry);
5372 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5374 event->rcu_batches = get_state_synchronize_rcu();
5375 event->rcu_pending = 1;
5379 if (event->rcu_pending) {
5380 cond_synchronize_rcu(event->rcu_batches);
5381 event->rcu_pending = 0;
5384 spin_lock_irqsave(&rb->event_lock, flags);
5385 list_add_rcu(&event->rb_entry, &rb->event_list);
5386 spin_unlock_irqrestore(&rb->event_lock, flags);
5390 * Avoid racing with perf_mmap_close(AUX): stop the event
5391 * before swizzling the event::rb pointer; if it's getting
5392 * unmapped, its aux_mmap_count will be 0 and it won't
5393 * restart. See the comment in __perf_pmu_output_stop().
5395 * Data will inevitably be lost when set_output is done in
5396 * mid-air, but then again, whoever does it like this is
5397 * not in for the data anyway.
5400 perf_event_stop(event, 0);
5402 rcu_assign_pointer(event->rb, rb);
5405 ring_buffer_put(old_rb);
5407 * Since we detached before setting the new rb, so that we
5408 * could attach the new rb, we could have missed a wakeup.
5411 wake_up_all(&event->waitq);
5415 static void ring_buffer_wakeup(struct perf_event *event)
5417 struct ring_buffer *rb;
5420 rb = rcu_dereference(event->rb);
5422 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5423 wake_up_all(&event->waitq);
5428 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5430 struct ring_buffer *rb;
5433 rb = rcu_dereference(event->rb);
5435 if (!atomic_inc_not_zero(&rb->refcount))
5443 void ring_buffer_put(struct ring_buffer *rb)
5445 if (!atomic_dec_and_test(&rb->refcount))
5448 WARN_ON_ONCE(!list_empty(&rb->event_list));
5450 call_rcu(&rb->rcu_head, rb_free_rcu);
5453 static void perf_mmap_open(struct vm_area_struct *vma)
5455 struct perf_event *event = vma->vm_file->private_data;
5457 atomic_inc(&event->mmap_count);
5458 atomic_inc(&event->rb->mmap_count);
5461 atomic_inc(&event->rb->aux_mmap_count);
5463 if (event->pmu->event_mapped)
5464 event->pmu->event_mapped(event, vma->vm_mm);
5467 static void perf_pmu_output_stop(struct perf_event *event);
5470 * A buffer can be mmap()ed multiple times; either directly through the same
5471 * event, or through other events by use of perf_event_set_output().
5473 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5474 * the buffer here, where we still have a VM context. This means we need
5475 * to detach all events redirecting to us.
5477 static void perf_mmap_close(struct vm_area_struct *vma)
5479 struct perf_event *event = vma->vm_file->private_data;
5480 struct ring_buffer *rb = ring_buffer_get(event);
5481 struct user_struct *mmap_user = rb->mmap_user;
5482 int mmap_locked = rb->mmap_locked;
5483 unsigned long size = perf_data_size(rb);
5484 bool detach_rest = false;
5486 if (event->pmu->event_unmapped)
5487 event->pmu->event_unmapped(event, vma->vm_mm);
5490 * rb->aux_mmap_count will always drop before rb->mmap_count and
5491 * event->mmap_count, so it is ok to use event->mmap_mutex to
5492 * serialize with perf_mmap here.
5494 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5495 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5497 * Stop all AUX events that are writing to this buffer,
5498 * so that we can free its AUX pages and corresponding PMU
5499 * data. Note that after rb::aux_mmap_count dropped to zero,
5500 * they won't start any more (see perf_aux_output_begin()).
5502 perf_pmu_output_stop(event);
5504 /* now it's safe to free the pages */
5505 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5506 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5508 /* this has to be the last one */
5510 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5512 mutex_unlock(&event->mmap_mutex);
5515 if (atomic_dec_and_test(&rb->mmap_count))
5518 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5521 ring_buffer_attach(event, NULL);
5522 mutex_unlock(&event->mmap_mutex);
5524 /* If there's still other mmap()s of this buffer, we're done. */
5529 * No other mmap()s, detach from all other events that might redirect
5530 * into the now unreachable buffer. Somewhat complicated by the
5531 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5535 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5536 if (!atomic_long_inc_not_zero(&event->refcount)) {
5538 * This event is en-route to free_event() which will
5539 * detach it and remove it from the list.
5545 mutex_lock(&event->mmap_mutex);
5547 * Check we didn't race with perf_event_set_output() which can
5548 * swizzle the rb from under us while we were waiting to
5549 * acquire mmap_mutex.
5551 * If we find a different rb; ignore this event, a next
5552 * iteration will no longer find it on the list. We have to
5553 * still restart the iteration to make sure we're not now
5554 * iterating the wrong list.
5556 if (event->rb == rb)
5557 ring_buffer_attach(event, NULL);
5559 mutex_unlock(&event->mmap_mutex);
5563 * Restart the iteration; either we're on the wrong list or
5564 * destroyed its integrity by doing a deletion.
5571 * It could be there's still a few 0-ref events on the list; they'll
5572 * get cleaned up by free_event() -- they'll also still have their
5573 * ref on the rb and will free it whenever they are done with it.
5575 * Aside from that, this buffer is 'fully' detached and unmapped,
5576 * undo the VM accounting.
5579 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5580 vma->vm_mm->pinned_vm -= mmap_locked;
5581 free_uid(mmap_user);
5584 ring_buffer_put(rb); /* could be last */
5587 static const struct vm_operations_struct perf_mmap_vmops = {
5588 .open = perf_mmap_open,
5589 .close = perf_mmap_close, /* non mergable */
5590 .fault = perf_mmap_fault,
5591 .page_mkwrite = perf_mmap_fault,
5594 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5596 struct perf_event *event = file->private_data;
5597 unsigned long user_locked, user_lock_limit;
5598 struct user_struct *user = current_user();
5599 unsigned long locked, lock_limit;
5600 struct ring_buffer *rb = NULL;
5601 unsigned long vma_size;
5602 unsigned long nr_pages;
5603 long user_extra = 0, extra = 0;
5604 int ret = 0, flags = 0;
5607 * Don't allow mmap() of inherited per-task counters. This would
5608 * create a performance issue due to all children writing to the
5611 if (event->cpu == -1 && event->attr.inherit)
5614 if (!(vma->vm_flags & VM_SHARED))
5617 vma_size = vma->vm_end - vma->vm_start;
5619 if (vma->vm_pgoff == 0) {
5620 nr_pages = (vma_size / PAGE_SIZE) - 1;
5623 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5624 * mapped, all subsequent mappings should have the same size
5625 * and offset. Must be above the normal perf buffer.
5627 u64 aux_offset, aux_size;
5632 nr_pages = vma_size / PAGE_SIZE;
5634 mutex_lock(&event->mmap_mutex);
5641 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5642 aux_size = READ_ONCE(rb->user_page->aux_size);
5644 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5647 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5650 /* already mapped with a different offset */
5651 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5654 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5657 /* already mapped with a different size */
5658 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5661 if (!is_power_of_2(nr_pages))
5664 if (!atomic_inc_not_zero(&rb->mmap_count))
5667 if (rb_has_aux(rb)) {
5668 atomic_inc(&rb->aux_mmap_count);
5673 atomic_set(&rb->aux_mmap_count, 1);
5674 user_extra = nr_pages;
5680 * If we have rb pages ensure they're a power-of-two number, so we
5681 * can do bitmasks instead of modulo.
5683 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5686 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5689 WARN_ON_ONCE(event->ctx->parent_ctx);
5691 mutex_lock(&event->mmap_mutex);
5693 if (event->rb->nr_pages != nr_pages) {
5698 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5700 * Raced against perf_mmap_close() through
5701 * perf_event_set_output(). Try again, hope for better
5704 mutex_unlock(&event->mmap_mutex);
5711 user_extra = nr_pages + 1;
5714 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5717 * Increase the limit linearly with more CPUs:
5719 user_lock_limit *= num_online_cpus();
5721 user_locked = atomic_long_read(&user->locked_vm);
5724 * sysctl_perf_event_mlock may have changed, so that
5725 * user->locked_vm > user_lock_limit
5727 if (user_locked > user_lock_limit)
5728 user_locked = user_lock_limit;
5729 user_locked += user_extra;
5731 if (user_locked > user_lock_limit)
5732 extra = user_locked - user_lock_limit;
5734 lock_limit = rlimit(RLIMIT_MEMLOCK);
5735 lock_limit >>= PAGE_SHIFT;
5736 locked = vma->vm_mm->pinned_vm + extra;
5738 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5739 !capable(CAP_IPC_LOCK)) {
5744 WARN_ON(!rb && event->rb);
5746 if (vma->vm_flags & VM_WRITE)
5747 flags |= RING_BUFFER_WRITABLE;
5750 rb = rb_alloc(nr_pages,
5751 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5759 atomic_set(&rb->mmap_count, 1);
5760 rb->mmap_user = get_current_user();
5761 rb->mmap_locked = extra;
5763 ring_buffer_attach(event, rb);
5765 perf_event_init_userpage(event);
5766 perf_event_update_userpage(event);
5768 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5769 event->attr.aux_watermark, flags);
5771 rb->aux_mmap_locked = extra;
5776 atomic_long_add(user_extra, &user->locked_vm);
5777 vma->vm_mm->pinned_vm += extra;
5779 atomic_inc(&event->mmap_count);
5781 atomic_dec(&rb->mmap_count);
5784 mutex_unlock(&event->mmap_mutex);
5787 * Since pinned accounting is per vm we cannot allow fork() to copy our
5790 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5791 vma->vm_ops = &perf_mmap_vmops;
5793 if (event->pmu->event_mapped)
5794 event->pmu->event_mapped(event, vma->vm_mm);
5799 static int perf_fasync(int fd, struct file *filp, int on)
5801 struct inode *inode = file_inode(filp);
5802 struct perf_event *event = filp->private_data;
5806 retval = fasync_helper(fd, filp, on, &event->fasync);
5807 inode_unlock(inode);
5815 static const struct file_operations perf_fops = {
5816 .llseek = no_llseek,
5817 .release = perf_release,
5820 .unlocked_ioctl = perf_ioctl,
5821 .compat_ioctl = perf_compat_ioctl,
5823 .fasync = perf_fasync,
5829 * If there's data, ensure we set the poll() state and publish everything
5830 * to user-space before waking everybody up.
5833 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5835 /* only the parent has fasync state */
5837 event = event->parent;
5838 return &event->fasync;
5841 void perf_event_wakeup(struct perf_event *event)
5843 ring_buffer_wakeup(event);
5845 if (event->pending_kill) {
5846 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5847 event->pending_kill = 0;
5851 static void perf_pending_event_disable(struct perf_event *event)
5853 int cpu = READ_ONCE(event->pending_disable);
5858 if (cpu == smp_processor_id()) {
5859 WRITE_ONCE(event->pending_disable, -1);
5860 perf_event_disable_local(event);
5867 * perf_event_disable_inatomic()
5868 * @pending_disable = CPU-A;
5872 * @pending_disable = -1;
5875 * perf_event_disable_inatomic()
5876 * @pending_disable = CPU-B;
5877 * irq_work_queue(); // FAILS
5880 * perf_pending_event()
5882 * But the event runs on CPU-B and wants disabling there.
5884 irq_work_queue_on(&event->pending, cpu);
5887 static void perf_pending_event(struct irq_work *entry)
5889 struct perf_event *event = container_of(entry, struct perf_event, pending);
5892 rctx = perf_swevent_get_recursion_context();
5894 * If we 'fail' here, that's OK, it means recursion is already disabled
5895 * and we won't recurse 'further'.
5898 perf_pending_event_disable(event);
5900 if (event->pending_wakeup) {
5901 event->pending_wakeup = 0;
5902 perf_event_wakeup(event);
5906 perf_swevent_put_recursion_context(rctx);
5910 * We assume there is only KVM supporting the callbacks.
5911 * Later on, we might change it to a list if there is
5912 * another virtualization implementation supporting the callbacks.
5914 struct perf_guest_info_callbacks *perf_guest_cbs;
5916 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5918 perf_guest_cbs = cbs;
5921 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5923 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5925 perf_guest_cbs = NULL;
5928 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5931 perf_output_sample_regs(struct perf_output_handle *handle,
5932 struct pt_regs *regs, u64 mask)
5935 DECLARE_BITMAP(_mask, 64);
5937 bitmap_from_u64(_mask, mask);
5938 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5941 val = perf_reg_value(regs, bit);
5942 perf_output_put(handle, val);
5946 static void perf_sample_regs_user(struct perf_regs *regs_user,
5947 struct pt_regs *regs,
5948 struct pt_regs *regs_user_copy)
5950 if (user_mode(regs)) {
5951 regs_user->abi = perf_reg_abi(current);
5952 regs_user->regs = regs;
5953 } else if (!(current->flags & PF_KTHREAD)) {
5954 perf_get_regs_user(regs_user, regs, regs_user_copy);
5956 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5957 regs_user->regs = NULL;
5961 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5962 struct pt_regs *regs)
5964 regs_intr->regs = regs;
5965 regs_intr->abi = perf_reg_abi(current);
5970 * Get remaining task size from user stack pointer.
5972 * It'd be better to take stack vma map and limit this more
5973 * precisly, but there's no way to get it safely under interrupt,
5974 * so using TASK_SIZE as limit.
5976 static u64 perf_ustack_task_size(struct pt_regs *regs)
5978 unsigned long addr = perf_user_stack_pointer(regs);
5980 if (!addr || addr >= TASK_SIZE)
5983 return TASK_SIZE - addr;
5987 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5988 struct pt_regs *regs)
5992 /* No regs, no stack pointer, no dump. */
5997 * Check if we fit in with the requested stack size into the:
5999 * If we don't, we limit the size to the TASK_SIZE.
6001 * - remaining sample size
6002 * If we don't, we customize the stack size to
6003 * fit in to the remaining sample size.
6006 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6007 stack_size = min(stack_size, (u16) task_size);
6009 /* Current header size plus static size and dynamic size. */
6010 header_size += 2 * sizeof(u64);
6012 /* Do we fit in with the current stack dump size? */
6013 if ((u16) (header_size + stack_size) < header_size) {
6015 * If we overflow the maximum size for the sample,
6016 * we customize the stack dump size to fit in.
6018 stack_size = USHRT_MAX - header_size - sizeof(u64);
6019 stack_size = round_up(stack_size, sizeof(u64));
6026 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6027 struct pt_regs *regs)
6029 /* Case of a kernel thread, nothing to dump */
6032 perf_output_put(handle, size);
6042 * - the size requested by user or the best one we can fit
6043 * in to the sample max size
6045 * - user stack dump data
6047 * - the actual dumped size
6051 perf_output_put(handle, dump_size);
6054 sp = perf_user_stack_pointer(regs);
6057 rem = __output_copy_user(handle, (void *) sp, dump_size);
6059 dyn_size = dump_size - rem;
6061 perf_output_skip(handle, rem);
6064 perf_output_put(handle, dyn_size);
6068 static void __perf_event_header__init_id(struct perf_event_header *header,
6069 struct perf_sample_data *data,
6070 struct perf_event *event)
6072 u64 sample_type = event->attr.sample_type;
6074 data->type = sample_type;
6075 header->size += event->id_header_size;
6077 if (sample_type & PERF_SAMPLE_TID) {
6078 /* namespace issues */
6079 data->tid_entry.pid = perf_event_pid(event, current);
6080 data->tid_entry.tid = perf_event_tid(event, current);
6083 if (sample_type & PERF_SAMPLE_TIME)
6084 data->time = perf_event_clock(event);
6086 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6087 data->id = primary_event_id(event);
6089 if (sample_type & PERF_SAMPLE_STREAM_ID)
6090 data->stream_id = event->id;
6092 if (sample_type & PERF_SAMPLE_CPU) {
6093 data->cpu_entry.cpu = raw_smp_processor_id();
6094 data->cpu_entry.reserved = 0;
6098 void perf_event_header__init_id(struct perf_event_header *header,
6099 struct perf_sample_data *data,
6100 struct perf_event *event)
6102 if (event->attr.sample_id_all)
6103 __perf_event_header__init_id(header, data, event);
6106 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6107 struct perf_sample_data *data)
6109 u64 sample_type = data->type;
6111 if (sample_type & PERF_SAMPLE_TID)
6112 perf_output_put(handle, data->tid_entry);
6114 if (sample_type & PERF_SAMPLE_TIME)
6115 perf_output_put(handle, data->time);
6117 if (sample_type & PERF_SAMPLE_ID)
6118 perf_output_put(handle, data->id);
6120 if (sample_type & PERF_SAMPLE_STREAM_ID)
6121 perf_output_put(handle, data->stream_id);
6123 if (sample_type & PERF_SAMPLE_CPU)
6124 perf_output_put(handle, data->cpu_entry);
6126 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6127 perf_output_put(handle, data->id);
6130 void perf_event__output_id_sample(struct perf_event *event,
6131 struct perf_output_handle *handle,
6132 struct perf_sample_data *sample)
6134 if (event->attr.sample_id_all)
6135 __perf_event__output_id_sample(handle, sample);
6138 static void perf_output_read_one(struct perf_output_handle *handle,
6139 struct perf_event *event,
6140 u64 enabled, u64 running)
6142 u64 read_format = event->attr.read_format;
6146 values[n++] = perf_event_count(event);
6147 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6148 values[n++] = enabled +
6149 atomic64_read(&event->child_total_time_enabled);
6151 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6152 values[n++] = running +
6153 atomic64_read(&event->child_total_time_running);
6155 if (read_format & PERF_FORMAT_ID)
6156 values[n++] = primary_event_id(event);
6158 __output_copy(handle, values, n * sizeof(u64));
6161 static void perf_output_read_group(struct perf_output_handle *handle,
6162 struct perf_event *event,
6163 u64 enabled, u64 running)
6165 struct perf_event *leader = event->group_leader, *sub;
6166 u64 read_format = event->attr.read_format;
6170 values[n++] = 1 + leader->nr_siblings;
6172 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6173 values[n++] = enabled;
6175 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6176 values[n++] = running;
6178 if ((leader != event) &&
6179 (leader->state == PERF_EVENT_STATE_ACTIVE))
6180 leader->pmu->read(leader);
6182 values[n++] = perf_event_count(leader);
6183 if (read_format & PERF_FORMAT_ID)
6184 values[n++] = primary_event_id(leader);
6186 __output_copy(handle, values, n * sizeof(u64));
6188 for_each_sibling_event(sub, leader) {
6191 if ((sub != event) &&
6192 (sub->state == PERF_EVENT_STATE_ACTIVE))
6193 sub->pmu->read(sub);
6195 values[n++] = perf_event_count(sub);
6196 if (read_format & PERF_FORMAT_ID)
6197 values[n++] = primary_event_id(sub);
6199 __output_copy(handle, values, n * sizeof(u64));
6203 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6204 PERF_FORMAT_TOTAL_TIME_RUNNING)
6207 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6209 * The problem is that its both hard and excessively expensive to iterate the
6210 * child list, not to mention that its impossible to IPI the children running
6211 * on another CPU, from interrupt/NMI context.
6213 static void perf_output_read(struct perf_output_handle *handle,
6214 struct perf_event *event)
6216 u64 enabled = 0, running = 0, now;
6217 u64 read_format = event->attr.read_format;
6220 * compute total_time_enabled, total_time_running
6221 * based on snapshot values taken when the event
6222 * was last scheduled in.
6224 * we cannot simply called update_context_time()
6225 * because of locking issue as we are called in
6228 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6229 calc_timer_values(event, &now, &enabled, &running);
6231 if (event->attr.read_format & PERF_FORMAT_GROUP)
6232 perf_output_read_group(handle, event, enabled, running);
6234 perf_output_read_one(handle, event, enabled, running);
6237 void perf_output_sample(struct perf_output_handle *handle,
6238 struct perf_event_header *header,
6239 struct perf_sample_data *data,
6240 struct perf_event *event)
6242 u64 sample_type = data->type;
6244 perf_output_put(handle, *header);
6246 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6247 perf_output_put(handle, data->id);
6249 if (sample_type & PERF_SAMPLE_IP)
6250 perf_output_put(handle, data->ip);
6252 if (sample_type & PERF_SAMPLE_TID)
6253 perf_output_put(handle, data->tid_entry);
6255 if (sample_type & PERF_SAMPLE_TIME)
6256 perf_output_put(handle, data->time);
6258 if (sample_type & PERF_SAMPLE_ADDR)
6259 perf_output_put(handle, data->addr);
6261 if (sample_type & PERF_SAMPLE_ID)
6262 perf_output_put(handle, data->id);
6264 if (sample_type & PERF_SAMPLE_STREAM_ID)
6265 perf_output_put(handle, data->stream_id);
6267 if (sample_type & PERF_SAMPLE_CPU)
6268 perf_output_put(handle, data->cpu_entry);
6270 if (sample_type & PERF_SAMPLE_PERIOD)
6271 perf_output_put(handle, data->period);
6273 if (sample_type & PERF_SAMPLE_READ)
6274 perf_output_read(handle, event);
6276 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6279 size += data->callchain->nr;
6280 size *= sizeof(u64);
6281 __output_copy(handle, data->callchain, size);
6284 if (sample_type & PERF_SAMPLE_RAW) {
6285 struct perf_raw_record *raw = data->raw;
6288 struct perf_raw_frag *frag = &raw->frag;
6290 perf_output_put(handle, raw->size);
6293 __output_custom(handle, frag->copy,
6294 frag->data, frag->size);
6296 __output_copy(handle, frag->data,
6299 if (perf_raw_frag_last(frag))
6304 __output_skip(handle, NULL, frag->pad);
6310 .size = sizeof(u32),
6313 perf_output_put(handle, raw);
6317 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6318 if (data->br_stack) {
6321 size = data->br_stack->nr
6322 * sizeof(struct perf_branch_entry);
6324 perf_output_put(handle, data->br_stack->nr);
6325 perf_output_copy(handle, data->br_stack->entries, size);
6328 * we always store at least the value of nr
6331 perf_output_put(handle, nr);
6335 if (sample_type & PERF_SAMPLE_REGS_USER) {
6336 u64 abi = data->regs_user.abi;
6339 * If there are no regs to dump, notice it through
6340 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6342 perf_output_put(handle, abi);
6345 u64 mask = event->attr.sample_regs_user;
6346 perf_output_sample_regs(handle,
6347 data->regs_user.regs,
6352 if (sample_type & PERF_SAMPLE_STACK_USER) {
6353 perf_output_sample_ustack(handle,
6354 data->stack_user_size,
6355 data->regs_user.regs);
6358 if (sample_type & PERF_SAMPLE_WEIGHT)
6359 perf_output_put(handle, data->weight);
6361 if (sample_type & PERF_SAMPLE_DATA_SRC)
6362 perf_output_put(handle, data->data_src.val);
6364 if (sample_type & PERF_SAMPLE_TRANSACTION)
6365 perf_output_put(handle, data->txn);
6367 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6368 u64 abi = data->regs_intr.abi;
6370 * If there are no regs to dump, notice it through
6371 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6373 perf_output_put(handle, abi);
6376 u64 mask = event->attr.sample_regs_intr;
6378 perf_output_sample_regs(handle,
6379 data->regs_intr.regs,
6384 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6385 perf_output_put(handle, data->phys_addr);
6387 if (!event->attr.watermark) {
6388 int wakeup_events = event->attr.wakeup_events;
6390 if (wakeup_events) {
6391 struct ring_buffer *rb = handle->rb;
6392 int events = local_inc_return(&rb->events);
6394 if (events >= wakeup_events) {
6395 local_sub(wakeup_events, &rb->events);
6396 local_inc(&rb->wakeup);
6402 static u64 perf_virt_to_phys(u64 virt)
6405 struct page *p = NULL;
6410 if (virt >= TASK_SIZE) {
6411 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6412 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6413 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6414 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6417 * Walking the pages tables for user address.
6418 * Interrupts are disabled, so it prevents any tear down
6419 * of the page tables.
6420 * Try IRQ-safe __get_user_pages_fast first.
6421 * If failed, leave phys_addr as 0.
6423 if (current->mm != NULL) {
6424 pagefault_disable();
6425 if (__get_user_pages_fast(virt, 1, 0, &p) == 1)
6426 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6437 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6439 struct perf_callchain_entry *
6440 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6442 bool kernel = !event->attr.exclude_callchain_kernel;
6443 bool user = !event->attr.exclude_callchain_user;
6444 /* Disallow cross-task user callchains. */
6445 bool crosstask = event->ctx->task && event->ctx->task != current;
6446 const u32 max_stack = event->attr.sample_max_stack;
6447 struct perf_callchain_entry *callchain;
6449 if (!kernel && !user)
6450 return &__empty_callchain;
6452 callchain = get_perf_callchain(regs, 0, kernel, user,
6453 max_stack, crosstask, true);
6454 return callchain ?: &__empty_callchain;
6457 void perf_prepare_sample(struct perf_event_header *header,
6458 struct perf_sample_data *data,
6459 struct perf_event *event,
6460 struct pt_regs *regs)
6462 u64 sample_type = event->attr.sample_type;
6464 header->type = PERF_RECORD_SAMPLE;
6465 header->size = sizeof(*header) + event->header_size;
6468 header->misc |= perf_misc_flags(regs);
6470 __perf_event_header__init_id(header, data, event);
6472 if (sample_type & PERF_SAMPLE_IP)
6473 data->ip = perf_instruction_pointer(regs);
6475 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6478 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6479 data->callchain = perf_callchain(event, regs);
6481 size += data->callchain->nr;
6483 header->size += size * sizeof(u64);
6486 if (sample_type & PERF_SAMPLE_RAW) {
6487 struct perf_raw_record *raw = data->raw;
6491 struct perf_raw_frag *frag = &raw->frag;
6496 if (perf_raw_frag_last(frag))
6501 size = round_up(sum + sizeof(u32), sizeof(u64));
6502 raw->size = size - sizeof(u32);
6503 frag->pad = raw->size - sum;
6508 header->size += size;
6511 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6512 int size = sizeof(u64); /* nr */
6513 if (data->br_stack) {
6514 size += data->br_stack->nr
6515 * sizeof(struct perf_branch_entry);
6517 header->size += size;
6520 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6521 perf_sample_regs_user(&data->regs_user, regs,
6522 &data->regs_user_copy);
6524 if (sample_type & PERF_SAMPLE_REGS_USER) {
6525 /* regs dump ABI info */
6526 int size = sizeof(u64);
6528 if (data->regs_user.regs) {
6529 u64 mask = event->attr.sample_regs_user;
6530 size += hweight64(mask) * sizeof(u64);
6533 header->size += size;
6536 if (sample_type & PERF_SAMPLE_STACK_USER) {
6538 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6539 * processed as the last one or have additional check added
6540 * in case new sample type is added, because we could eat
6541 * up the rest of the sample size.
6543 u16 stack_size = event->attr.sample_stack_user;
6544 u16 size = sizeof(u64);
6546 stack_size = perf_sample_ustack_size(stack_size, header->size,
6547 data->regs_user.regs);
6550 * If there is something to dump, add space for the dump
6551 * itself and for the field that tells the dynamic size,
6552 * which is how many have been actually dumped.
6555 size += sizeof(u64) + stack_size;
6557 data->stack_user_size = stack_size;
6558 header->size += size;
6561 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6562 /* regs dump ABI info */
6563 int size = sizeof(u64);
6565 perf_sample_regs_intr(&data->regs_intr, regs);
6567 if (data->regs_intr.regs) {
6568 u64 mask = event->attr.sample_regs_intr;
6570 size += hweight64(mask) * sizeof(u64);
6573 header->size += size;
6576 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6577 data->phys_addr = perf_virt_to_phys(data->addr);
6580 static __always_inline void
6581 __perf_event_output(struct perf_event *event,
6582 struct perf_sample_data *data,
6583 struct pt_regs *regs,
6584 int (*output_begin)(struct perf_output_handle *,
6585 struct perf_event *,
6588 struct perf_output_handle handle;
6589 struct perf_event_header header;
6591 /* protect the callchain buffers */
6594 perf_prepare_sample(&header, data, event, regs);
6596 if (output_begin(&handle, event, header.size))
6599 perf_output_sample(&handle, &header, data, event);
6601 perf_output_end(&handle);
6608 perf_event_output_forward(struct perf_event *event,
6609 struct perf_sample_data *data,
6610 struct pt_regs *regs)
6612 __perf_event_output(event, data, regs, perf_output_begin_forward);
6616 perf_event_output_backward(struct perf_event *event,
6617 struct perf_sample_data *data,
6618 struct pt_regs *regs)
6620 __perf_event_output(event, data, regs, perf_output_begin_backward);
6624 perf_event_output(struct perf_event *event,
6625 struct perf_sample_data *data,
6626 struct pt_regs *regs)
6628 __perf_event_output(event, data, regs, perf_output_begin);
6635 struct perf_read_event {
6636 struct perf_event_header header;
6643 perf_event_read_event(struct perf_event *event,
6644 struct task_struct *task)
6646 struct perf_output_handle handle;
6647 struct perf_sample_data sample;
6648 struct perf_read_event read_event = {
6650 .type = PERF_RECORD_READ,
6652 .size = sizeof(read_event) + event->read_size,
6654 .pid = perf_event_pid(event, task),
6655 .tid = perf_event_tid(event, task),
6659 perf_event_header__init_id(&read_event.header, &sample, event);
6660 ret = perf_output_begin(&handle, event, read_event.header.size);
6664 perf_output_put(&handle, read_event);
6665 perf_output_read(&handle, event);
6666 perf_event__output_id_sample(event, &handle, &sample);
6668 perf_output_end(&handle);
6671 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6674 perf_iterate_ctx(struct perf_event_context *ctx,
6675 perf_iterate_f output,
6676 void *data, bool all)
6678 struct perf_event *event;
6680 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6682 if (event->state < PERF_EVENT_STATE_INACTIVE)
6684 if (!event_filter_match(event))
6688 output(event, data);
6692 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6694 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6695 struct perf_event *event;
6697 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6699 * Skip events that are not fully formed yet; ensure that
6700 * if we observe event->ctx, both event and ctx will be
6701 * complete enough. See perf_install_in_context().
6703 if (!smp_load_acquire(&event->ctx))
6706 if (event->state < PERF_EVENT_STATE_INACTIVE)
6708 if (!event_filter_match(event))
6710 output(event, data);
6715 * Iterate all events that need to receive side-band events.
6717 * For new callers; ensure that account_pmu_sb_event() includes
6718 * your event, otherwise it might not get delivered.
6721 perf_iterate_sb(perf_iterate_f output, void *data,
6722 struct perf_event_context *task_ctx)
6724 struct perf_event_context *ctx;
6731 * If we have task_ctx != NULL we only notify the task context itself.
6732 * The task_ctx is set only for EXIT events before releasing task
6736 perf_iterate_ctx(task_ctx, output, data, false);
6740 perf_iterate_sb_cpu(output, data);
6742 for_each_task_context_nr(ctxn) {
6743 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6745 perf_iterate_ctx(ctx, output, data, false);
6753 * Clear all file-based filters at exec, they'll have to be
6754 * re-instated when/if these objects are mmapped again.
6756 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6758 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6759 struct perf_addr_filter *filter;
6760 unsigned int restart = 0, count = 0;
6761 unsigned long flags;
6763 if (!has_addr_filter(event))
6766 raw_spin_lock_irqsave(&ifh->lock, flags);
6767 list_for_each_entry(filter, &ifh->list, entry) {
6768 if (filter->path.dentry) {
6769 event->addr_filter_ranges[count].start = 0;
6770 event->addr_filter_ranges[count].size = 0;
6778 event->addr_filters_gen++;
6779 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6782 perf_event_stop(event, 1);
6785 void perf_event_exec(void)
6787 struct perf_event_context *ctx;
6791 for_each_task_context_nr(ctxn) {
6792 ctx = current->perf_event_ctxp[ctxn];
6796 perf_event_enable_on_exec(ctxn);
6798 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6804 struct remote_output {
6805 struct ring_buffer *rb;
6809 static void __perf_event_output_stop(struct perf_event *event, void *data)
6811 struct perf_event *parent = event->parent;
6812 struct remote_output *ro = data;
6813 struct ring_buffer *rb = ro->rb;
6814 struct stop_event_data sd = {
6818 if (!has_aux(event))
6825 * In case of inheritance, it will be the parent that links to the
6826 * ring-buffer, but it will be the child that's actually using it.
6828 * We are using event::rb to determine if the event should be stopped,
6829 * however this may race with ring_buffer_attach() (through set_output),
6830 * which will make us skip the event that actually needs to be stopped.
6831 * So ring_buffer_attach() has to stop an aux event before re-assigning
6834 if (rcu_dereference(parent->rb) == rb)
6835 ro->err = __perf_event_stop(&sd);
6838 static int __perf_pmu_output_stop(void *info)
6840 struct perf_event *event = info;
6841 struct pmu *pmu = event->ctx->pmu;
6842 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6843 struct remote_output ro = {
6848 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6849 if (cpuctx->task_ctx)
6850 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6857 static void perf_pmu_output_stop(struct perf_event *event)
6859 struct perf_event *iter;
6864 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6866 * For per-CPU events, we need to make sure that neither they
6867 * nor their children are running; for cpu==-1 events it's
6868 * sufficient to stop the event itself if it's active, since
6869 * it can't have children.
6873 cpu = READ_ONCE(iter->oncpu);
6878 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6879 if (err == -EAGAIN) {
6888 * task tracking -- fork/exit
6890 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6893 struct perf_task_event {
6894 struct task_struct *task;
6895 struct perf_event_context *task_ctx;
6898 struct perf_event_header header;
6908 static int perf_event_task_match(struct perf_event *event)
6910 return event->attr.comm || event->attr.mmap ||
6911 event->attr.mmap2 || event->attr.mmap_data ||
6915 static void perf_event_task_output(struct perf_event *event,
6918 struct perf_task_event *task_event = data;
6919 struct perf_output_handle handle;
6920 struct perf_sample_data sample;
6921 struct task_struct *task = task_event->task;
6922 int ret, size = task_event->event_id.header.size;
6924 if (!perf_event_task_match(event))
6927 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6929 ret = perf_output_begin(&handle, event,
6930 task_event->event_id.header.size);
6934 task_event->event_id.pid = perf_event_pid(event, task);
6935 task_event->event_id.tid = perf_event_tid(event, task);
6937 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
6938 task_event->event_id.ppid = perf_event_pid(event,
6940 task_event->event_id.ptid = perf_event_pid(event,
6942 } else { /* PERF_RECORD_FORK */
6943 task_event->event_id.ppid = perf_event_pid(event, current);
6944 task_event->event_id.ptid = perf_event_tid(event, current);
6947 task_event->event_id.time = perf_event_clock(event);
6949 perf_output_put(&handle, task_event->event_id);
6951 perf_event__output_id_sample(event, &handle, &sample);
6953 perf_output_end(&handle);
6955 task_event->event_id.header.size = size;
6958 static void perf_event_task(struct task_struct *task,
6959 struct perf_event_context *task_ctx,
6962 struct perf_task_event task_event;
6964 if (!atomic_read(&nr_comm_events) &&
6965 !atomic_read(&nr_mmap_events) &&
6966 !atomic_read(&nr_task_events))
6969 task_event = (struct perf_task_event){
6971 .task_ctx = task_ctx,
6974 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6976 .size = sizeof(task_event.event_id),
6986 perf_iterate_sb(perf_event_task_output,
6991 void perf_event_fork(struct task_struct *task)
6993 perf_event_task(task, NULL, 1);
6994 perf_event_namespaces(task);
7001 struct perf_comm_event {
7002 struct task_struct *task;
7007 struct perf_event_header header;
7014 static int perf_event_comm_match(struct perf_event *event)
7016 return event->attr.comm;
7019 static void perf_event_comm_output(struct perf_event *event,
7022 struct perf_comm_event *comm_event = data;
7023 struct perf_output_handle handle;
7024 struct perf_sample_data sample;
7025 int size = comm_event->event_id.header.size;
7028 if (!perf_event_comm_match(event))
7031 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7032 ret = perf_output_begin(&handle, event,
7033 comm_event->event_id.header.size);
7038 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7039 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7041 perf_output_put(&handle, comm_event->event_id);
7042 __output_copy(&handle, comm_event->comm,
7043 comm_event->comm_size);
7045 perf_event__output_id_sample(event, &handle, &sample);
7047 perf_output_end(&handle);
7049 comm_event->event_id.header.size = size;
7052 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7054 char comm[TASK_COMM_LEN];
7057 memset(comm, 0, sizeof(comm));
7058 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7059 size = ALIGN(strlen(comm)+1, sizeof(u64));
7061 comm_event->comm = comm;
7062 comm_event->comm_size = size;
7064 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7066 perf_iterate_sb(perf_event_comm_output,
7071 void perf_event_comm(struct task_struct *task, bool exec)
7073 struct perf_comm_event comm_event;
7075 if (!atomic_read(&nr_comm_events))
7078 comm_event = (struct perf_comm_event){
7084 .type = PERF_RECORD_COMM,
7085 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7093 perf_event_comm_event(&comm_event);
7097 * namespaces tracking
7100 struct perf_namespaces_event {
7101 struct task_struct *task;
7104 struct perf_event_header header;
7109 struct perf_ns_link_info link_info[NR_NAMESPACES];
7113 static int perf_event_namespaces_match(struct perf_event *event)
7115 return event->attr.namespaces;
7118 static void perf_event_namespaces_output(struct perf_event *event,
7121 struct perf_namespaces_event *namespaces_event = data;
7122 struct perf_output_handle handle;
7123 struct perf_sample_data sample;
7124 u16 header_size = namespaces_event->event_id.header.size;
7127 if (!perf_event_namespaces_match(event))
7130 perf_event_header__init_id(&namespaces_event->event_id.header,
7132 ret = perf_output_begin(&handle, event,
7133 namespaces_event->event_id.header.size);
7137 namespaces_event->event_id.pid = perf_event_pid(event,
7138 namespaces_event->task);
7139 namespaces_event->event_id.tid = perf_event_tid(event,
7140 namespaces_event->task);
7142 perf_output_put(&handle, namespaces_event->event_id);
7144 perf_event__output_id_sample(event, &handle, &sample);
7146 perf_output_end(&handle);
7148 namespaces_event->event_id.header.size = header_size;
7151 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7152 struct task_struct *task,
7153 const struct proc_ns_operations *ns_ops)
7155 struct path ns_path;
7156 struct inode *ns_inode;
7159 error = ns_get_path(&ns_path, task, ns_ops);
7161 ns_inode = ns_path.dentry->d_inode;
7162 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7163 ns_link_info->ino = ns_inode->i_ino;
7168 void perf_event_namespaces(struct task_struct *task)
7170 struct perf_namespaces_event namespaces_event;
7171 struct perf_ns_link_info *ns_link_info;
7173 if (!atomic_read(&nr_namespaces_events))
7176 namespaces_event = (struct perf_namespaces_event){
7180 .type = PERF_RECORD_NAMESPACES,
7182 .size = sizeof(namespaces_event.event_id),
7186 .nr_namespaces = NR_NAMESPACES,
7187 /* .link_info[NR_NAMESPACES] */
7191 ns_link_info = namespaces_event.event_id.link_info;
7193 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7194 task, &mntns_operations);
7196 #ifdef CONFIG_USER_NS
7197 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7198 task, &userns_operations);
7200 #ifdef CONFIG_NET_NS
7201 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7202 task, &netns_operations);
7204 #ifdef CONFIG_UTS_NS
7205 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7206 task, &utsns_operations);
7208 #ifdef CONFIG_IPC_NS
7209 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7210 task, &ipcns_operations);
7212 #ifdef CONFIG_PID_NS
7213 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7214 task, &pidns_operations);
7216 #ifdef CONFIG_CGROUPS
7217 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7218 task, &cgroupns_operations);
7221 perf_iterate_sb(perf_event_namespaces_output,
7230 struct perf_mmap_event {
7231 struct vm_area_struct *vma;
7233 const char *file_name;
7241 struct perf_event_header header;
7251 static int perf_event_mmap_match(struct perf_event *event,
7254 struct perf_mmap_event *mmap_event = data;
7255 struct vm_area_struct *vma = mmap_event->vma;
7256 int executable = vma->vm_flags & VM_EXEC;
7258 return (!executable && event->attr.mmap_data) ||
7259 (executable && (event->attr.mmap || event->attr.mmap2));
7262 static void perf_event_mmap_output(struct perf_event *event,
7265 struct perf_mmap_event *mmap_event = data;
7266 struct perf_output_handle handle;
7267 struct perf_sample_data sample;
7268 int size = mmap_event->event_id.header.size;
7269 u32 type = mmap_event->event_id.header.type;
7272 if (!perf_event_mmap_match(event, data))
7275 if (event->attr.mmap2) {
7276 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7277 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7278 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7279 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7280 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7281 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7282 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7285 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7286 ret = perf_output_begin(&handle, event,
7287 mmap_event->event_id.header.size);
7291 mmap_event->event_id.pid = perf_event_pid(event, current);
7292 mmap_event->event_id.tid = perf_event_tid(event, current);
7294 perf_output_put(&handle, mmap_event->event_id);
7296 if (event->attr.mmap2) {
7297 perf_output_put(&handle, mmap_event->maj);
7298 perf_output_put(&handle, mmap_event->min);
7299 perf_output_put(&handle, mmap_event->ino);
7300 perf_output_put(&handle, mmap_event->ino_generation);
7301 perf_output_put(&handle, mmap_event->prot);
7302 perf_output_put(&handle, mmap_event->flags);
7305 __output_copy(&handle, mmap_event->file_name,
7306 mmap_event->file_size);
7308 perf_event__output_id_sample(event, &handle, &sample);
7310 perf_output_end(&handle);
7312 mmap_event->event_id.header.size = size;
7313 mmap_event->event_id.header.type = type;
7316 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7318 struct vm_area_struct *vma = mmap_event->vma;
7319 struct file *file = vma->vm_file;
7320 int maj = 0, min = 0;
7321 u64 ino = 0, gen = 0;
7322 u32 prot = 0, flags = 0;
7328 if (vma->vm_flags & VM_READ)
7330 if (vma->vm_flags & VM_WRITE)
7332 if (vma->vm_flags & VM_EXEC)
7335 if (vma->vm_flags & VM_MAYSHARE)
7338 flags = MAP_PRIVATE;
7340 if (vma->vm_flags & VM_DENYWRITE)
7341 flags |= MAP_DENYWRITE;
7342 if (vma->vm_flags & VM_MAYEXEC)
7343 flags |= MAP_EXECUTABLE;
7344 if (vma->vm_flags & VM_LOCKED)
7345 flags |= MAP_LOCKED;
7346 if (vma->vm_flags & VM_HUGETLB)
7347 flags |= MAP_HUGETLB;
7350 struct inode *inode;
7353 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7359 * d_path() works from the end of the rb backwards, so we
7360 * need to add enough zero bytes after the string to handle
7361 * the 64bit alignment we do later.
7363 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7368 inode = file_inode(vma->vm_file);
7369 dev = inode->i_sb->s_dev;
7371 gen = inode->i_generation;
7377 if (vma->vm_ops && vma->vm_ops->name) {
7378 name = (char *) vma->vm_ops->name(vma);
7383 name = (char *)arch_vma_name(vma);
7387 if (vma->vm_start <= vma->vm_mm->start_brk &&
7388 vma->vm_end >= vma->vm_mm->brk) {
7392 if (vma->vm_start <= vma->vm_mm->start_stack &&
7393 vma->vm_end >= vma->vm_mm->start_stack) {
7403 strlcpy(tmp, name, sizeof(tmp));
7407 * Since our buffer works in 8 byte units we need to align our string
7408 * size to a multiple of 8. However, we must guarantee the tail end is
7409 * zero'd out to avoid leaking random bits to userspace.
7411 size = strlen(name)+1;
7412 while (!IS_ALIGNED(size, sizeof(u64)))
7413 name[size++] = '\0';
7415 mmap_event->file_name = name;
7416 mmap_event->file_size = size;
7417 mmap_event->maj = maj;
7418 mmap_event->min = min;
7419 mmap_event->ino = ino;
7420 mmap_event->ino_generation = gen;
7421 mmap_event->prot = prot;
7422 mmap_event->flags = flags;
7424 if (!(vma->vm_flags & VM_EXEC))
7425 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7427 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7429 perf_iterate_sb(perf_event_mmap_output,
7437 * Check whether inode and address range match filter criteria.
7439 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7440 struct file *file, unsigned long offset,
7443 /* d_inode(NULL) won't be equal to any mapped user-space file */
7444 if (!filter->path.dentry)
7447 if (d_inode(filter->path.dentry) != file_inode(file))
7450 if (filter->offset > offset + size)
7453 if (filter->offset + filter->size < offset)
7459 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7460 struct vm_area_struct *vma,
7461 struct perf_addr_filter_range *fr)
7463 unsigned long vma_size = vma->vm_end - vma->vm_start;
7464 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7465 struct file *file = vma->vm_file;
7467 if (!perf_addr_filter_match(filter, file, off, vma_size))
7470 if (filter->offset < off) {
7471 fr->start = vma->vm_start;
7472 fr->size = min(vma_size, filter->size - (off - filter->offset));
7474 fr->start = vma->vm_start + filter->offset - off;
7475 fr->size = min(vma->vm_end - fr->start, filter->size);
7481 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7483 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7484 struct vm_area_struct *vma = data;
7485 struct perf_addr_filter *filter;
7486 unsigned int restart = 0, count = 0;
7487 unsigned long flags;
7489 if (!has_addr_filter(event))
7495 raw_spin_lock_irqsave(&ifh->lock, flags);
7496 list_for_each_entry(filter, &ifh->list, entry) {
7497 if (perf_addr_filter_vma_adjust(filter, vma,
7498 &event->addr_filter_ranges[count]))
7505 event->addr_filters_gen++;
7506 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7509 perf_event_stop(event, 1);
7513 * Adjust all task's events' filters to the new vma
7515 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7517 struct perf_event_context *ctx;
7521 * Data tracing isn't supported yet and as such there is no need
7522 * to keep track of anything that isn't related to executable code:
7524 if (!(vma->vm_flags & VM_EXEC))
7528 for_each_task_context_nr(ctxn) {
7529 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7533 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7538 void perf_event_mmap(struct vm_area_struct *vma)
7540 struct perf_mmap_event mmap_event;
7542 if (!atomic_read(&nr_mmap_events))
7545 mmap_event = (struct perf_mmap_event){
7551 .type = PERF_RECORD_MMAP,
7552 .misc = PERF_RECORD_MISC_USER,
7557 .start = vma->vm_start,
7558 .len = vma->vm_end - vma->vm_start,
7559 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7561 /* .maj (attr_mmap2 only) */
7562 /* .min (attr_mmap2 only) */
7563 /* .ino (attr_mmap2 only) */
7564 /* .ino_generation (attr_mmap2 only) */
7565 /* .prot (attr_mmap2 only) */
7566 /* .flags (attr_mmap2 only) */
7569 perf_addr_filters_adjust(vma);
7570 perf_event_mmap_event(&mmap_event);
7573 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7574 unsigned long size, u64 flags)
7576 struct perf_output_handle handle;
7577 struct perf_sample_data sample;
7578 struct perf_aux_event {
7579 struct perf_event_header header;
7585 .type = PERF_RECORD_AUX,
7587 .size = sizeof(rec),
7595 perf_event_header__init_id(&rec.header, &sample, event);
7596 ret = perf_output_begin(&handle, event, rec.header.size);
7601 perf_output_put(&handle, rec);
7602 perf_event__output_id_sample(event, &handle, &sample);
7604 perf_output_end(&handle);
7608 * Lost/dropped samples logging
7610 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7612 struct perf_output_handle handle;
7613 struct perf_sample_data sample;
7617 struct perf_event_header header;
7619 } lost_samples_event = {
7621 .type = PERF_RECORD_LOST_SAMPLES,
7623 .size = sizeof(lost_samples_event),
7628 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7630 ret = perf_output_begin(&handle, event,
7631 lost_samples_event.header.size);
7635 perf_output_put(&handle, lost_samples_event);
7636 perf_event__output_id_sample(event, &handle, &sample);
7637 perf_output_end(&handle);
7641 * context_switch tracking
7644 struct perf_switch_event {
7645 struct task_struct *task;
7646 struct task_struct *next_prev;
7649 struct perf_event_header header;
7655 static int perf_event_switch_match(struct perf_event *event)
7657 return event->attr.context_switch;
7660 static void perf_event_switch_output(struct perf_event *event, void *data)
7662 struct perf_switch_event *se = data;
7663 struct perf_output_handle handle;
7664 struct perf_sample_data sample;
7667 if (!perf_event_switch_match(event))
7670 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7671 if (event->ctx->task) {
7672 se->event_id.header.type = PERF_RECORD_SWITCH;
7673 se->event_id.header.size = sizeof(se->event_id.header);
7675 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7676 se->event_id.header.size = sizeof(se->event_id);
7677 se->event_id.next_prev_pid =
7678 perf_event_pid(event, se->next_prev);
7679 se->event_id.next_prev_tid =
7680 perf_event_tid(event, se->next_prev);
7683 perf_event_header__init_id(&se->event_id.header, &sample, event);
7685 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7689 if (event->ctx->task)
7690 perf_output_put(&handle, se->event_id.header);
7692 perf_output_put(&handle, se->event_id);
7694 perf_event__output_id_sample(event, &handle, &sample);
7696 perf_output_end(&handle);
7699 static void perf_event_switch(struct task_struct *task,
7700 struct task_struct *next_prev, bool sched_in)
7702 struct perf_switch_event switch_event;
7704 /* N.B. caller checks nr_switch_events != 0 */
7706 switch_event = (struct perf_switch_event){
7708 .next_prev = next_prev,
7712 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7715 /* .next_prev_pid */
7716 /* .next_prev_tid */
7720 if (!sched_in && task->state == TASK_RUNNING)
7721 switch_event.event_id.header.misc |=
7722 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7724 perf_iterate_sb(perf_event_switch_output,
7730 * IRQ throttle logging
7733 static void perf_log_throttle(struct perf_event *event, int enable)
7735 struct perf_output_handle handle;
7736 struct perf_sample_data sample;
7740 struct perf_event_header header;
7744 } throttle_event = {
7746 .type = PERF_RECORD_THROTTLE,
7748 .size = sizeof(throttle_event),
7750 .time = perf_event_clock(event),
7751 .id = primary_event_id(event),
7752 .stream_id = event->id,
7756 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7758 perf_event_header__init_id(&throttle_event.header, &sample, event);
7760 ret = perf_output_begin(&handle, event,
7761 throttle_event.header.size);
7765 perf_output_put(&handle, throttle_event);
7766 perf_event__output_id_sample(event, &handle, &sample);
7767 perf_output_end(&handle);
7770 void perf_event_itrace_started(struct perf_event *event)
7772 event->attach_state |= PERF_ATTACH_ITRACE;
7775 static void perf_log_itrace_start(struct perf_event *event)
7777 struct perf_output_handle handle;
7778 struct perf_sample_data sample;
7779 struct perf_aux_event {
7780 struct perf_event_header header;
7787 event = event->parent;
7789 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7790 event->attach_state & PERF_ATTACH_ITRACE)
7793 rec.header.type = PERF_RECORD_ITRACE_START;
7794 rec.header.misc = 0;
7795 rec.header.size = sizeof(rec);
7796 rec.pid = perf_event_pid(event, current);
7797 rec.tid = perf_event_tid(event, current);
7799 perf_event_header__init_id(&rec.header, &sample, event);
7800 ret = perf_output_begin(&handle, event, rec.header.size);
7805 perf_output_put(&handle, rec);
7806 perf_event__output_id_sample(event, &handle, &sample);
7808 perf_output_end(&handle);
7812 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7814 struct hw_perf_event *hwc = &event->hw;
7818 seq = __this_cpu_read(perf_throttled_seq);
7819 if (seq != hwc->interrupts_seq) {
7820 hwc->interrupts_seq = seq;
7821 hwc->interrupts = 1;
7824 if (unlikely(throttle
7825 && hwc->interrupts >= max_samples_per_tick)) {
7826 __this_cpu_inc(perf_throttled_count);
7827 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7828 hwc->interrupts = MAX_INTERRUPTS;
7829 perf_log_throttle(event, 0);
7834 if (event->attr.freq) {
7835 u64 now = perf_clock();
7836 s64 delta = now - hwc->freq_time_stamp;
7838 hwc->freq_time_stamp = now;
7840 if (delta > 0 && delta < 2*TICK_NSEC)
7841 perf_adjust_period(event, delta, hwc->last_period, true);
7847 int perf_event_account_interrupt(struct perf_event *event)
7849 return __perf_event_account_interrupt(event, 1);
7853 * Generic event overflow handling, sampling.
7856 static int __perf_event_overflow(struct perf_event *event,
7857 int throttle, struct perf_sample_data *data,
7858 struct pt_regs *regs)
7860 int events = atomic_read(&event->event_limit);
7864 * Non-sampling counters might still use the PMI to fold short
7865 * hardware counters, ignore those.
7867 if (unlikely(!is_sampling_event(event)))
7870 ret = __perf_event_account_interrupt(event, throttle);
7873 * XXX event_limit might not quite work as expected on inherited
7877 event->pending_kill = POLL_IN;
7878 if (events && atomic_dec_and_test(&event->event_limit)) {
7880 event->pending_kill = POLL_HUP;
7882 perf_event_disable_inatomic(event);
7885 READ_ONCE(event->overflow_handler)(event, data, regs);
7887 if (*perf_event_fasync(event) && event->pending_kill) {
7888 event->pending_wakeup = 1;
7889 irq_work_queue(&event->pending);
7895 int perf_event_overflow(struct perf_event *event,
7896 struct perf_sample_data *data,
7897 struct pt_regs *regs)
7899 return __perf_event_overflow(event, 1, data, regs);
7903 * Generic software event infrastructure
7906 struct swevent_htable {
7907 struct swevent_hlist *swevent_hlist;
7908 struct mutex hlist_mutex;
7911 /* Recursion avoidance in each contexts */
7912 int recursion[PERF_NR_CONTEXTS];
7915 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7918 * We directly increment event->count and keep a second value in
7919 * event->hw.period_left to count intervals. This period event
7920 * is kept in the range [-sample_period, 0] so that we can use the
7924 u64 perf_swevent_set_period(struct perf_event *event)
7926 struct hw_perf_event *hwc = &event->hw;
7927 u64 period = hwc->last_period;
7931 hwc->last_period = hwc->sample_period;
7934 old = val = local64_read(&hwc->period_left);
7938 nr = div64_u64(period + val, period);
7939 offset = nr * period;
7941 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7947 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7948 struct perf_sample_data *data,
7949 struct pt_regs *regs)
7951 struct hw_perf_event *hwc = &event->hw;
7955 overflow = perf_swevent_set_period(event);
7957 if (hwc->interrupts == MAX_INTERRUPTS)
7960 for (; overflow; overflow--) {
7961 if (__perf_event_overflow(event, throttle,
7964 * We inhibit the overflow from happening when
7965 * hwc->interrupts == MAX_INTERRUPTS.
7973 static void perf_swevent_event(struct perf_event *event, u64 nr,
7974 struct perf_sample_data *data,
7975 struct pt_regs *regs)
7977 struct hw_perf_event *hwc = &event->hw;
7979 local64_add(nr, &event->count);
7984 if (!is_sampling_event(event))
7987 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7989 return perf_swevent_overflow(event, 1, data, regs);
7991 data->period = event->hw.last_period;
7993 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7994 return perf_swevent_overflow(event, 1, data, regs);
7996 if (local64_add_negative(nr, &hwc->period_left))
7999 perf_swevent_overflow(event, 0, data, regs);
8002 static int perf_exclude_event(struct perf_event *event,
8003 struct pt_regs *regs)
8005 if (event->hw.state & PERF_HES_STOPPED)
8009 if (event->attr.exclude_user && user_mode(regs))
8012 if (event->attr.exclude_kernel && !user_mode(regs))
8019 static int perf_swevent_match(struct perf_event *event,
8020 enum perf_type_id type,
8022 struct perf_sample_data *data,
8023 struct pt_regs *regs)
8025 if (event->attr.type != type)
8028 if (event->attr.config != event_id)
8031 if (perf_exclude_event(event, regs))
8037 static inline u64 swevent_hash(u64 type, u32 event_id)
8039 u64 val = event_id | (type << 32);
8041 return hash_64(val, SWEVENT_HLIST_BITS);
8044 static inline struct hlist_head *
8045 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8047 u64 hash = swevent_hash(type, event_id);
8049 return &hlist->heads[hash];
8052 /* For the read side: events when they trigger */
8053 static inline struct hlist_head *
8054 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8056 struct swevent_hlist *hlist;
8058 hlist = rcu_dereference(swhash->swevent_hlist);
8062 return __find_swevent_head(hlist, type, event_id);
8065 /* For the event head insertion and removal in the hlist */
8066 static inline struct hlist_head *
8067 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8069 struct swevent_hlist *hlist;
8070 u32 event_id = event->attr.config;
8071 u64 type = event->attr.type;
8074 * Event scheduling is always serialized against hlist allocation
8075 * and release. Which makes the protected version suitable here.
8076 * The context lock guarantees that.
8078 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8079 lockdep_is_held(&event->ctx->lock));
8083 return __find_swevent_head(hlist, type, event_id);
8086 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8088 struct perf_sample_data *data,
8089 struct pt_regs *regs)
8091 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8092 struct perf_event *event;
8093 struct hlist_head *head;
8096 head = find_swevent_head_rcu(swhash, type, event_id);
8100 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8101 if (perf_swevent_match(event, type, event_id, data, regs))
8102 perf_swevent_event(event, nr, data, regs);
8108 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8110 int perf_swevent_get_recursion_context(void)
8112 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8114 return get_recursion_context(swhash->recursion);
8116 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8118 void perf_swevent_put_recursion_context(int rctx)
8120 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8122 put_recursion_context(swhash->recursion, rctx);
8125 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8127 struct perf_sample_data data;
8129 if (WARN_ON_ONCE(!regs))
8132 perf_sample_data_init(&data, addr, 0);
8133 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8136 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8140 preempt_disable_notrace();
8141 rctx = perf_swevent_get_recursion_context();
8142 if (unlikely(rctx < 0))
8145 ___perf_sw_event(event_id, nr, regs, addr);
8147 perf_swevent_put_recursion_context(rctx);
8149 preempt_enable_notrace();
8152 static void perf_swevent_read(struct perf_event *event)
8156 static int perf_swevent_add(struct perf_event *event, int flags)
8158 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8159 struct hw_perf_event *hwc = &event->hw;
8160 struct hlist_head *head;
8162 if (is_sampling_event(event)) {
8163 hwc->last_period = hwc->sample_period;
8164 perf_swevent_set_period(event);
8167 hwc->state = !(flags & PERF_EF_START);
8169 head = find_swevent_head(swhash, event);
8170 if (WARN_ON_ONCE(!head))
8173 hlist_add_head_rcu(&event->hlist_entry, head);
8174 perf_event_update_userpage(event);
8179 static void perf_swevent_del(struct perf_event *event, int flags)
8181 hlist_del_rcu(&event->hlist_entry);
8184 static void perf_swevent_start(struct perf_event *event, int flags)
8186 event->hw.state = 0;
8189 static void perf_swevent_stop(struct perf_event *event, int flags)
8191 event->hw.state = PERF_HES_STOPPED;
8194 /* Deref the hlist from the update side */
8195 static inline struct swevent_hlist *
8196 swevent_hlist_deref(struct swevent_htable *swhash)
8198 return rcu_dereference_protected(swhash->swevent_hlist,
8199 lockdep_is_held(&swhash->hlist_mutex));
8202 static void swevent_hlist_release(struct swevent_htable *swhash)
8204 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8209 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8210 kfree_rcu(hlist, rcu_head);
8213 static void swevent_hlist_put_cpu(int cpu)
8215 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8217 mutex_lock(&swhash->hlist_mutex);
8219 if (!--swhash->hlist_refcount)
8220 swevent_hlist_release(swhash);
8222 mutex_unlock(&swhash->hlist_mutex);
8225 static void swevent_hlist_put(void)
8229 for_each_possible_cpu(cpu)
8230 swevent_hlist_put_cpu(cpu);
8233 static int swevent_hlist_get_cpu(int cpu)
8235 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8238 mutex_lock(&swhash->hlist_mutex);
8239 if (!swevent_hlist_deref(swhash) &&
8240 cpumask_test_cpu(cpu, perf_online_mask)) {
8241 struct swevent_hlist *hlist;
8243 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8248 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8250 swhash->hlist_refcount++;
8252 mutex_unlock(&swhash->hlist_mutex);
8257 static int swevent_hlist_get(void)
8259 int err, cpu, failed_cpu;
8261 mutex_lock(&pmus_lock);
8262 for_each_possible_cpu(cpu) {
8263 err = swevent_hlist_get_cpu(cpu);
8269 mutex_unlock(&pmus_lock);
8272 for_each_possible_cpu(cpu) {
8273 if (cpu == failed_cpu)
8275 swevent_hlist_put_cpu(cpu);
8277 mutex_unlock(&pmus_lock);
8281 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8283 static void sw_perf_event_destroy(struct perf_event *event)
8285 u64 event_id = event->attr.config;
8287 WARN_ON(event->parent);
8289 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8290 swevent_hlist_put();
8293 static int perf_swevent_init(struct perf_event *event)
8295 u64 event_id = event->attr.config;
8297 if (event->attr.type != PERF_TYPE_SOFTWARE)
8301 * no branch sampling for software events
8303 if (has_branch_stack(event))
8307 case PERF_COUNT_SW_CPU_CLOCK:
8308 case PERF_COUNT_SW_TASK_CLOCK:
8315 if (event_id >= PERF_COUNT_SW_MAX)
8318 if (!event->parent) {
8321 err = swevent_hlist_get();
8325 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8326 event->destroy = sw_perf_event_destroy;
8332 static struct pmu perf_swevent = {
8333 .task_ctx_nr = perf_sw_context,
8335 .capabilities = PERF_PMU_CAP_NO_NMI,
8337 .event_init = perf_swevent_init,
8338 .add = perf_swevent_add,
8339 .del = perf_swevent_del,
8340 .start = perf_swevent_start,
8341 .stop = perf_swevent_stop,
8342 .read = perf_swevent_read,
8345 #ifdef CONFIG_EVENT_TRACING
8347 static int perf_tp_filter_match(struct perf_event *event,
8348 struct perf_sample_data *data)
8350 void *record = data->raw->frag.data;
8352 /* only top level events have filters set */
8354 event = event->parent;
8356 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8361 static int perf_tp_event_match(struct perf_event *event,
8362 struct perf_sample_data *data,
8363 struct pt_regs *regs)
8365 if (event->hw.state & PERF_HES_STOPPED)
8368 * All tracepoints are from kernel-space.
8370 if (event->attr.exclude_kernel)
8373 if (!perf_tp_filter_match(event, data))
8379 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8380 struct trace_event_call *call, u64 count,
8381 struct pt_regs *regs, struct hlist_head *head,
8382 struct task_struct *task)
8384 if (bpf_prog_array_valid(call)) {
8385 *(struct pt_regs **)raw_data = regs;
8386 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8387 perf_swevent_put_recursion_context(rctx);
8391 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8394 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8396 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8397 struct pt_regs *regs, struct hlist_head *head, int rctx,
8398 struct task_struct *task)
8400 struct perf_sample_data data;
8401 struct perf_event *event;
8403 struct perf_raw_record raw = {
8410 perf_sample_data_init(&data, 0, 0);
8413 perf_trace_buf_update(record, event_type);
8415 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8416 if (perf_tp_event_match(event, &data, regs))
8417 perf_swevent_event(event, count, &data, regs);
8421 * If we got specified a target task, also iterate its context and
8422 * deliver this event there too.
8424 if (task && task != current) {
8425 struct perf_event_context *ctx;
8426 struct trace_entry *entry = record;
8429 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8433 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8434 if (event->cpu != smp_processor_id())
8436 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8438 if (event->attr.config != entry->type)
8440 if (perf_tp_event_match(event, &data, regs))
8441 perf_swevent_event(event, count, &data, regs);
8447 perf_swevent_put_recursion_context(rctx);
8449 EXPORT_SYMBOL_GPL(perf_tp_event);
8451 static void tp_perf_event_destroy(struct perf_event *event)
8453 perf_trace_destroy(event);
8456 static int perf_tp_event_init(struct perf_event *event)
8460 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8464 * no branch sampling for tracepoint events
8466 if (has_branch_stack(event))
8469 err = perf_trace_init(event);
8473 event->destroy = tp_perf_event_destroy;
8478 static struct pmu perf_tracepoint = {
8479 .task_ctx_nr = perf_sw_context,
8481 .event_init = perf_tp_event_init,
8482 .add = perf_trace_add,
8483 .del = perf_trace_del,
8484 .start = perf_swevent_start,
8485 .stop = perf_swevent_stop,
8486 .read = perf_swevent_read,
8489 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8491 * Flags in config, used by dynamic PMU kprobe and uprobe
8492 * The flags should match following PMU_FORMAT_ATTR().
8494 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8495 * if not set, create kprobe/uprobe
8497 enum perf_probe_config {
8498 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8501 PMU_FORMAT_ATTR(retprobe, "config:0");
8503 static struct attribute *probe_attrs[] = {
8504 &format_attr_retprobe.attr,
8508 static struct attribute_group probe_format_group = {
8510 .attrs = probe_attrs,
8513 static const struct attribute_group *probe_attr_groups[] = {
8514 &probe_format_group,
8519 #ifdef CONFIG_KPROBE_EVENTS
8520 static int perf_kprobe_event_init(struct perf_event *event);
8521 static struct pmu perf_kprobe = {
8522 .task_ctx_nr = perf_sw_context,
8523 .event_init = perf_kprobe_event_init,
8524 .add = perf_trace_add,
8525 .del = perf_trace_del,
8526 .start = perf_swevent_start,
8527 .stop = perf_swevent_stop,
8528 .read = perf_swevent_read,
8529 .attr_groups = probe_attr_groups,
8532 static int perf_kprobe_event_init(struct perf_event *event)
8537 if (event->attr.type != perf_kprobe.type)
8540 if (!capable(CAP_SYS_ADMIN))
8544 * no branch sampling for probe events
8546 if (has_branch_stack(event))
8549 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8550 err = perf_kprobe_init(event, is_retprobe);
8554 event->destroy = perf_kprobe_destroy;
8558 #endif /* CONFIG_KPROBE_EVENTS */
8560 #ifdef CONFIG_UPROBE_EVENTS
8561 static int perf_uprobe_event_init(struct perf_event *event);
8562 static struct pmu perf_uprobe = {
8563 .task_ctx_nr = perf_sw_context,
8564 .event_init = perf_uprobe_event_init,
8565 .add = perf_trace_add,
8566 .del = perf_trace_del,
8567 .start = perf_swevent_start,
8568 .stop = perf_swevent_stop,
8569 .read = perf_swevent_read,
8570 .attr_groups = probe_attr_groups,
8573 static int perf_uprobe_event_init(struct perf_event *event)
8578 if (event->attr.type != perf_uprobe.type)
8581 if (!capable(CAP_SYS_ADMIN))
8585 * no branch sampling for probe events
8587 if (has_branch_stack(event))
8590 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8591 err = perf_uprobe_init(event, is_retprobe);
8595 event->destroy = perf_uprobe_destroy;
8599 #endif /* CONFIG_UPROBE_EVENTS */
8601 static inline void perf_tp_register(void)
8603 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8604 #ifdef CONFIG_KPROBE_EVENTS
8605 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8607 #ifdef CONFIG_UPROBE_EVENTS
8608 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8612 static void perf_event_free_filter(struct perf_event *event)
8614 ftrace_profile_free_filter(event);
8617 #ifdef CONFIG_BPF_SYSCALL
8618 static void bpf_overflow_handler(struct perf_event *event,
8619 struct perf_sample_data *data,
8620 struct pt_regs *regs)
8622 struct bpf_perf_event_data_kern ctx = {
8628 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8630 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8633 ret = BPF_PROG_RUN(event->prog, &ctx);
8636 __this_cpu_dec(bpf_prog_active);
8641 event->orig_overflow_handler(event, data, regs);
8644 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8646 struct bpf_prog *prog;
8648 if (event->overflow_handler_context)
8649 /* hw breakpoint or kernel counter */
8655 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8657 return PTR_ERR(prog);
8660 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8661 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8665 static void perf_event_free_bpf_handler(struct perf_event *event)
8667 struct bpf_prog *prog = event->prog;
8672 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8677 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8681 static void perf_event_free_bpf_handler(struct perf_event *event)
8687 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8688 * with perf_event_open()
8690 static inline bool perf_event_is_tracing(struct perf_event *event)
8692 if (event->pmu == &perf_tracepoint)
8694 #ifdef CONFIG_KPROBE_EVENTS
8695 if (event->pmu == &perf_kprobe)
8698 #ifdef CONFIG_UPROBE_EVENTS
8699 if (event->pmu == &perf_uprobe)
8705 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8707 bool is_kprobe, is_tracepoint, is_syscall_tp;
8708 struct bpf_prog *prog;
8711 if (!perf_event_is_tracing(event))
8712 return perf_event_set_bpf_handler(event, prog_fd);
8714 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8715 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8716 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8717 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8718 /* bpf programs can only be attached to u/kprobe or tracepoint */
8721 prog = bpf_prog_get(prog_fd);
8723 return PTR_ERR(prog);
8725 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8726 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8727 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8728 /* valid fd, but invalid bpf program type */
8733 /* Kprobe override only works for kprobes, not uprobes. */
8734 if (prog->kprobe_override &&
8735 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8740 if (is_tracepoint || is_syscall_tp) {
8741 int off = trace_event_get_offsets(event->tp_event);
8743 if (prog->aux->max_ctx_offset > off) {
8749 ret = perf_event_attach_bpf_prog(event, prog);
8755 static void perf_event_free_bpf_prog(struct perf_event *event)
8757 if (!perf_event_is_tracing(event)) {
8758 perf_event_free_bpf_handler(event);
8761 perf_event_detach_bpf_prog(event);
8766 static inline void perf_tp_register(void)
8770 static void perf_event_free_filter(struct perf_event *event)
8774 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8779 static void perf_event_free_bpf_prog(struct perf_event *event)
8782 #endif /* CONFIG_EVENT_TRACING */
8784 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8785 void perf_bp_event(struct perf_event *bp, void *data)
8787 struct perf_sample_data sample;
8788 struct pt_regs *regs = data;
8790 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8792 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8793 perf_swevent_event(bp, 1, &sample, regs);
8798 * Allocate a new address filter
8800 static struct perf_addr_filter *
8801 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8803 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8804 struct perf_addr_filter *filter;
8806 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8810 INIT_LIST_HEAD(&filter->entry);
8811 list_add_tail(&filter->entry, filters);
8816 static void free_filters_list(struct list_head *filters)
8818 struct perf_addr_filter *filter, *iter;
8820 list_for_each_entry_safe(filter, iter, filters, entry) {
8821 path_put(&filter->path);
8822 list_del(&filter->entry);
8828 * Free existing address filters and optionally install new ones
8830 static void perf_addr_filters_splice(struct perf_event *event,
8831 struct list_head *head)
8833 unsigned long flags;
8836 if (!has_addr_filter(event))
8839 /* don't bother with children, they don't have their own filters */
8843 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8845 list_splice_init(&event->addr_filters.list, &list);
8847 list_splice(head, &event->addr_filters.list);
8849 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8851 free_filters_list(&list);
8855 * Scan through mm's vmas and see if one of them matches the
8856 * @filter; if so, adjust filter's address range.
8857 * Called with mm::mmap_sem down for reading.
8859 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
8860 struct mm_struct *mm,
8861 struct perf_addr_filter_range *fr)
8863 struct vm_area_struct *vma;
8865 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8869 if (perf_addr_filter_vma_adjust(filter, vma, fr))
8875 * Update event's address range filters based on the
8876 * task's existing mappings, if any.
8878 static void perf_event_addr_filters_apply(struct perf_event *event)
8880 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8881 struct task_struct *task = READ_ONCE(event->ctx->task);
8882 struct perf_addr_filter *filter;
8883 struct mm_struct *mm = NULL;
8884 unsigned int count = 0;
8885 unsigned long flags;
8888 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8889 * will stop on the parent's child_mutex that our caller is also holding
8891 if (task == TASK_TOMBSTONE)
8894 if (ifh->nr_file_filters) {
8895 mm = get_task_mm(event->ctx->task);
8899 down_read(&mm->mmap_sem);
8902 raw_spin_lock_irqsave(&ifh->lock, flags);
8903 list_for_each_entry(filter, &ifh->list, entry) {
8904 if (filter->path.dentry) {
8906 * Adjust base offset if the filter is associated to a
8907 * binary that needs to be mapped:
8909 event->addr_filter_ranges[count].start = 0;
8910 event->addr_filter_ranges[count].size = 0;
8912 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
8914 event->addr_filter_ranges[count].start = filter->offset;
8915 event->addr_filter_ranges[count].size = filter->size;
8921 event->addr_filters_gen++;
8922 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8924 if (ifh->nr_file_filters) {
8925 up_read(&mm->mmap_sem);
8931 perf_event_stop(event, 1);
8935 * Address range filtering: limiting the data to certain
8936 * instruction address ranges. Filters are ioctl()ed to us from
8937 * userspace as ascii strings.
8939 * Filter string format:
8942 * where ACTION is one of the
8943 * * "filter": limit the trace to this region
8944 * * "start": start tracing from this address
8945 * * "stop": stop tracing at this address/region;
8947 * * for kernel addresses: <start address>[/<size>]
8948 * * for object files: <start address>[/<size>]@</path/to/object/file>
8950 * if <size> is not specified or is zero, the range is treated as a single
8951 * address; not valid for ACTION=="filter".
8965 IF_STATE_ACTION = 0,
8970 static const match_table_t if_tokens = {
8971 { IF_ACT_FILTER, "filter" },
8972 { IF_ACT_START, "start" },
8973 { IF_ACT_STOP, "stop" },
8974 { IF_SRC_FILE, "%u/%u@%s" },
8975 { IF_SRC_KERNEL, "%u/%u" },
8976 { IF_SRC_FILEADDR, "%u@%s" },
8977 { IF_SRC_KERNELADDR, "%u" },
8978 { IF_ACT_NONE, NULL },
8982 * Address filter string parser
8985 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8986 struct list_head *filters)
8988 struct perf_addr_filter *filter = NULL;
8989 char *start, *orig, *filename = NULL;
8990 substring_t args[MAX_OPT_ARGS];
8991 int state = IF_STATE_ACTION, token;
8992 unsigned int kernel = 0;
8995 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8999 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9000 static const enum perf_addr_filter_action_t actions[] = {
9001 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9002 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9003 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9010 /* filter definition begins */
9011 if (state == IF_STATE_ACTION) {
9012 filter = perf_addr_filter_new(event, filters);
9017 token = match_token(start, if_tokens, args);
9022 if (state != IF_STATE_ACTION)
9025 filter->action = actions[token];
9026 state = IF_STATE_SOURCE;
9029 case IF_SRC_KERNELADDR:
9033 case IF_SRC_FILEADDR:
9035 if (state != IF_STATE_SOURCE)
9039 ret = kstrtoul(args[0].from, 0, &filter->offset);
9043 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9045 ret = kstrtoul(args[1].from, 0, &filter->size);
9050 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9051 int fpos = token == IF_SRC_FILE ? 2 : 1;
9054 filename = match_strdup(&args[fpos]);
9061 state = IF_STATE_END;
9069 * Filter definition is fully parsed, validate and install it.
9070 * Make sure that it doesn't contradict itself or the event's
9073 if (state == IF_STATE_END) {
9075 if (kernel && event->attr.exclude_kernel)
9079 * ACTION "filter" must have a non-zero length region
9082 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9091 * For now, we only support file-based filters
9092 * in per-task events; doing so for CPU-wide
9093 * events requires additional context switching
9094 * trickery, since same object code will be
9095 * mapped at different virtual addresses in
9096 * different processes.
9099 if (!event->ctx->task)
9102 /* look up the path and grab its inode */
9103 ret = kern_path(filename, LOOKUP_FOLLOW,
9109 if (!filter->path.dentry ||
9110 !S_ISREG(d_inode(filter->path.dentry)
9114 event->addr_filters.nr_file_filters++;
9117 /* ready to consume more filters */
9118 state = IF_STATE_ACTION;
9123 if (state != IF_STATE_ACTION)
9133 free_filters_list(filters);
9140 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9146 * Since this is called in perf_ioctl() path, we're already holding
9149 lockdep_assert_held(&event->ctx->mutex);
9151 if (WARN_ON_ONCE(event->parent))
9154 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9156 goto fail_clear_files;
9158 ret = event->pmu->addr_filters_validate(&filters);
9160 goto fail_free_filters;
9162 /* remove existing filters, if any */
9163 perf_addr_filters_splice(event, &filters);
9165 /* install new filters */
9166 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9171 free_filters_list(&filters);
9174 event->addr_filters.nr_file_filters = 0;
9179 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9184 filter_str = strndup_user(arg, PAGE_SIZE);
9185 if (IS_ERR(filter_str))
9186 return PTR_ERR(filter_str);
9188 #ifdef CONFIG_EVENT_TRACING
9189 if (perf_event_is_tracing(event)) {
9190 struct perf_event_context *ctx = event->ctx;
9193 * Beware, here be dragons!!
9195 * the tracepoint muck will deadlock against ctx->mutex, but
9196 * the tracepoint stuff does not actually need it. So
9197 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9198 * already have a reference on ctx.
9200 * This can result in event getting moved to a different ctx,
9201 * but that does not affect the tracepoint state.
9203 mutex_unlock(&ctx->mutex);
9204 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9205 mutex_lock(&ctx->mutex);
9208 if (has_addr_filter(event))
9209 ret = perf_event_set_addr_filter(event, filter_str);
9216 * hrtimer based swevent callback
9219 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9221 enum hrtimer_restart ret = HRTIMER_RESTART;
9222 struct perf_sample_data data;
9223 struct pt_regs *regs;
9224 struct perf_event *event;
9227 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9229 if (event->state != PERF_EVENT_STATE_ACTIVE)
9230 return HRTIMER_NORESTART;
9232 event->pmu->read(event);
9234 perf_sample_data_init(&data, 0, event->hw.last_period);
9235 regs = get_irq_regs();
9237 if (regs && !perf_exclude_event(event, regs)) {
9238 if (!(event->attr.exclude_idle && is_idle_task(current)))
9239 if (__perf_event_overflow(event, 1, &data, regs))
9240 ret = HRTIMER_NORESTART;
9243 period = max_t(u64, 10000, event->hw.sample_period);
9244 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9249 static void perf_swevent_start_hrtimer(struct perf_event *event)
9251 struct hw_perf_event *hwc = &event->hw;
9254 if (!is_sampling_event(event))
9257 period = local64_read(&hwc->period_left);
9262 local64_set(&hwc->period_left, 0);
9264 period = max_t(u64, 10000, hwc->sample_period);
9266 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9267 HRTIMER_MODE_REL_PINNED);
9270 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9272 struct hw_perf_event *hwc = &event->hw;
9274 if (is_sampling_event(event)) {
9275 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9276 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9278 hrtimer_cancel(&hwc->hrtimer);
9282 static void perf_swevent_init_hrtimer(struct perf_event *event)
9284 struct hw_perf_event *hwc = &event->hw;
9286 if (!is_sampling_event(event))
9289 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9290 hwc->hrtimer.function = perf_swevent_hrtimer;
9293 * Since hrtimers have a fixed rate, we can do a static freq->period
9294 * mapping and avoid the whole period adjust feedback stuff.
9296 if (event->attr.freq) {
9297 long freq = event->attr.sample_freq;
9299 event->attr.sample_period = NSEC_PER_SEC / freq;
9300 hwc->sample_period = event->attr.sample_period;
9301 local64_set(&hwc->period_left, hwc->sample_period);
9302 hwc->last_period = hwc->sample_period;
9303 event->attr.freq = 0;
9308 * Software event: cpu wall time clock
9311 static void cpu_clock_event_update(struct perf_event *event)
9316 now = local_clock();
9317 prev = local64_xchg(&event->hw.prev_count, now);
9318 local64_add(now - prev, &event->count);
9321 static void cpu_clock_event_start(struct perf_event *event, int flags)
9323 local64_set(&event->hw.prev_count, local_clock());
9324 perf_swevent_start_hrtimer(event);
9327 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9329 perf_swevent_cancel_hrtimer(event);
9330 cpu_clock_event_update(event);
9333 static int cpu_clock_event_add(struct perf_event *event, int flags)
9335 if (flags & PERF_EF_START)
9336 cpu_clock_event_start(event, flags);
9337 perf_event_update_userpage(event);
9342 static void cpu_clock_event_del(struct perf_event *event, int flags)
9344 cpu_clock_event_stop(event, flags);
9347 static void cpu_clock_event_read(struct perf_event *event)
9349 cpu_clock_event_update(event);
9352 static int cpu_clock_event_init(struct perf_event *event)
9354 if (event->attr.type != PERF_TYPE_SOFTWARE)
9357 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9361 * no branch sampling for software events
9363 if (has_branch_stack(event))
9366 perf_swevent_init_hrtimer(event);
9371 static struct pmu perf_cpu_clock = {
9372 .task_ctx_nr = perf_sw_context,
9374 .capabilities = PERF_PMU_CAP_NO_NMI,
9376 .event_init = cpu_clock_event_init,
9377 .add = cpu_clock_event_add,
9378 .del = cpu_clock_event_del,
9379 .start = cpu_clock_event_start,
9380 .stop = cpu_clock_event_stop,
9381 .read = cpu_clock_event_read,
9385 * Software event: task time clock
9388 static void task_clock_event_update(struct perf_event *event, u64 now)
9393 prev = local64_xchg(&event->hw.prev_count, now);
9395 local64_add(delta, &event->count);
9398 static void task_clock_event_start(struct perf_event *event, int flags)
9400 local64_set(&event->hw.prev_count, event->ctx->time);
9401 perf_swevent_start_hrtimer(event);
9404 static void task_clock_event_stop(struct perf_event *event, int flags)
9406 perf_swevent_cancel_hrtimer(event);
9407 task_clock_event_update(event, event->ctx->time);
9410 static int task_clock_event_add(struct perf_event *event, int flags)
9412 if (flags & PERF_EF_START)
9413 task_clock_event_start(event, flags);
9414 perf_event_update_userpage(event);
9419 static void task_clock_event_del(struct perf_event *event, int flags)
9421 task_clock_event_stop(event, PERF_EF_UPDATE);
9424 static void task_clock_event_read(struct perf_event *event)
9426 u64 now = perf_clock();
9427 u64 delta = now - event->ctx->timestamp;
9428 u64 time = event->ctx->time + delta;
9430 task_clock_event_update(event, time);
9433 static int task_clock_event_init(struct perf_event *event)
9435 if (event->attr.type != PERF_TYPE_SOFTWARE)
9438 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9442 * no branch sampling for software events
9444 if (has_branch_stack(event))
9447 perf_swevent_init_hrtimer(event);
9452 static struct pmu perf_task_clock = {
9453 .task_ctx_nr = perf_sw_context,
9455 .capabilities = PERF_PMU_CAP_NO_NMI,
9457 .event_init = task_clock_event_init,
9458 .add = task_clock_event_add,
9459 .del = task_clock_event_del,
9460 .start = task_clock_event_start,
9461 .stop = task_clock_event_stop,
9462 .read = task_clock_event_read,
9465 static void perf_pmu_nop_void(struct pmu *pmu)
9469 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9473 static int perf_pmu_nop_int(struct pmu *pmu)
9478 static int perf_event_nop_int(struct perf_event *event, u64 value)
9483 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9485 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9487 __this_cpu_write(nop_txn_flags, flags);
9489 if (flags & ~PERF_PMU_TXN_ADD)
9492 perf_pmu_disable(pmu);
9495 static int perf_pmu_commit_txn(struct pmu *pmu)
9497 unsigned int flags = __this_cpu_read(nop_txn_flags);
9499 __this_cpu_write(nop_txn_flags, 0);
9501 if (flags & ~PERF_PMU_TXN_ADD)
9504 perf_pmu_enable(pmu);
9508 static void perf_pmu_cancel_txn(struct pmu *pmu)
9510 unsigned int flags = __this_cpu_read(nop_txn_flags);
9512 __this_cpu_write(nop_txn_flags, 0);
9514 if (flags & ~PERF_PMU_TXN_ADD)
9517 perf_pmu_enable(pmu);
9520 static int perf_event_idx_default(struct perf_event *event)
9526 * Ensures all contexts with the same task_ctx_nr have the same
9527 * pmu_cpu_context too.
9529 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9536 list_for_each_entry(pmu, &pmus, entry) {
9537 if (pmu->task_ctx_nr == ctxn)
9538 return pmu->pmu_cpu_context;
9544 static void free_pmu_context(struct pmu *pmu)
9547 * Static contexts such as perf_sw_context have a global lifetime
9548 * and may be shared between different PMUs. Avoid freeing them
9549 * when a single PMU is going away.
9551 if (pmu->task_ctx_nr > perf_invalid_context)
9554 free_percpu(pmu->pmu_cpu_context);
9558 * Let userspace know that this PMU supports address range filtering:
9560 static ssize_t nr_addr_filters_show(struct device *dev,
9561 struct device_attribute *attr,
9564 struct pmu *pmu = dev_get_drvdata(dev);
9566 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9568 DEVICE_ATTR_RO(nr_addr_filters);
9570 static struct idr pmu_idr;
9573 type_show(struct device *dev, struct device_attribute *attr, char *page)
9575 struct pmu *pmu = dev_get_drvdata(dev);
9577 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9579 static DEVICE_ATTR_RO(type);
9582 perf_event_mux_interval_ms_show(struct device *dev,
9583 struct device_attribute *attr,
9586 struct pmu *pmu = dev_get_drvdata(dev);
9588 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9591 static DEFINE_MUTEX(mux_interval_mutex);
9594 perf_event_mux_interval_ms_store(struct device *dev,
9595 struct device_attribute *attr,
9596 const char *buf, size_t count)
9598 struct pmu *pmu = dev_get_drvdata(dev);
9599 int timer, cpu, ret;
9601 ret = kstrtoint(buf, 0, &timer);
9608 /* same value, noting to do */
9609 if (timer == pmu->hrtimer_interval_ms)
9612 mutex_lock(&mux_interval_mutex);
9613 pmu->hrtimer_interval_ms = timer;
9615 /* update all cpuctx for this PMU */
9617 for_each_online_cpu(cpu) {
9618 struct perf_cpu_context *cpuctx;
9619 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9620 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9622 cpu_function_call(cpu,
9623 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9626 mutex_unlock(&mux_interval_mutex);
9630 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9632 static struct attribute *pmu_dev_attrs[] = {
9633 &dev_attr_type.attr,
9634 &dev_attr_perf_event_mux_interval_ms.attr,
9637 ATTRIBUTE_GROUPS(pmu_dev);
9639 static int pmu_bus_running;
9640 static struct bus_type pmu_bus = {
9641 .name = "event_source",
9642 .dev_groups = pmu_dev_groups,
9645 static void pmu_dev_release(struct device *dev)
9650 static int pmu_dev_alloc(struct pmu *pmu)
9654 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9658 pmu->dev->groups = pmu->attr_groups;
9659 device_initialize(pmu->dev);
9660 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9664 dev_set_drvdata(pmu->dev, pmu);
9665 pmu->dev->bus = &pmu_bus;
9666 pmu->dev->release = pmu_dev_release;
9667 ret = device_add(pmu->dev);
9671 /* For PMUs with address filters, throw in an extra attribute: */
9672 if (pmu->nr_addr_filters)
9673 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9682 device_del(pmu->dev);
9685 put_device(pmu->dev);
9689 static struct lock_class_key cpuctx_mutex;
9690 static struct lock_class_key cpuctx_lock;
9692 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9696 mutex_lock(&pmus_lock);
9698 pmu->pmu_disable_count = alloc_percpu(int);
9699 if (!pmu->pmu_disable_count)
9708 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9716 if (pmu_bus_running) {
9717 ret = pmu_dev_alloc(pmu);
9723 if (pmu->task_ctx_nr == perf_hw_context) {
9724 static int hw_context_taken = 0;
9727 * Other than systems with heterogeneous CPUs, it never makes
9728 * sense for two PMUs to share perf_hw_context. PMUs which are
9729 * uncore must use perf_invalid_context.
9731 if (WARN_ON_ONCE(hw_context_taken &&
9732 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9733 pmu->task_ctx_nr = perf_invalid_context;
9735 hw_context_taken = 1;
9738 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9739 if (pmu->pmu_cpu_context)
9740 goto got_cpu_context;
9743 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9744 if (!pmu->pmu_cpu_context)
9747 for_each_possible_cpu(cpu) {
9748 struct perf_cpu_context *cpuctx;
9750 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9751 __perf_event_init_context(&cpuctx->ctx);
9752 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9753 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9754 cpuctx->ctx.pmu = pmu;
9755 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9757 __perf_mux_hrtimer_init(cpuctx, cpu);
9761 if (!pmu->start_txn) {
9762 if (pmu->pmu_enable) {
9764 * If we have pmu_enable/pmu_disable calls, install
9765 * transaction stubs that use that to try and batch
9766 * hardware accesses.
9768 pmu->start_txn = perf_pmu_start_txn;
9769 pmu->commit_txn = perf_pmu_commit_txn;
9770 pmu->cancel_txn = perf_pmu_cancel_txn;
9772 pmu->start_txn = perf_pmu_nop_txn;
9773 pmu->commit_txn = perf_pmu_nop_int;
9774 pmu->cancel_txn = perf_pmu_nop_void;
9778 if (!pmu->pmu_enable) {
9779 pmu->pmu_enable = perf_pmu_nop_void;
9780 pmu->pmu_disable = perf_pmu_nop_void;
9783 if (!pmu->check_period)
9784 pmu->check_period = perf_event_nop_int;
9786 if (!pmu->event_idx)
9787 pmu->event_idx = perf_event_idx_default;
9789 list_add_rcu(&pmu->entry, &pmus);
9790 atomic_set(&pmu->exclusive_cnt, 0);
9793 mutex_unlock(&pmus_lock);
9798 device_del(pmu->dev);
9799 put_device(pmu->dev);
9802 if (pmu->type >= PERF_TYPE_MAX)
9803 idr_remove(&pmu_idr, pmu->type);
9806 free_percpu(pmu->pmu_disable_count);
9809 EXPORT_SYMBOL_GPL(perf_pmu_register);
9811 void perf_pmu_unregister(struct pmu *pmu)
9813 mutex_lock(&pmus_lock);
9814 list_del_rcu(&pmu->entry);
9817 * We dereference the pmu list under both SRCU and regular RCU, so
9818 * synchronize against both of those.
9820 synchronize_srcu(&pmus_srcu);
9823 free_percpu(pmu->pmu_disable_count);
9824 if (pmu->type >= PERF_TYPE_MAX)
9825 idr_remove(&pmu_idr, pmu->type);
9826 if (pmu_bus_running) {
9827 if (pmu->nr_addr_filters)
9828 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9829 device_del(pmu->dev);
9830 put_device(pmu->dev);
9832 free_pmu_context(pmu);
9833 mutex_unlock(&pmus_lock);
9835 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9837 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9839 struct perf_event_context *ctx = NULL;
9842 if (!try_module_get(pmu->module))
9846 * A number of pmu->event_init() methods iterate the sibling_list to,
9847 * for example, validate if the group fits on the PMU. Therefore,
9848 * if this is a sibling event, acquire the ctx->mutex to protect
9851 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9853 * This ctx->mutex can nest when we're called through
9854 * inheritance. See the perf_event_ctx_lock_nested() comment.
9856 ctx = perf_event_ctx_lock_nested(event->group_leader,
9857 SINGLE_DEPTH_NESTING);
9862 ret = pmu->event_init(event);
9865 perf_event_ctx_unlock(event->group_leader, ctx);
9868 module_put(pmu->module);
9873 static struct pmu *perf_init_event(struct perf_event *event)
9879 idx = srcu_read_lock(&pmus_srcu);
9881 /* Try parent's PMU first: */
9882 if (event->parent && event->parent->pmu) {
9883 pmu = event->parent->pmu;
9884 ret = perf_try_init_event(pmu, event);
9890 pmu = idr_find(&pmu_idr, event->attr.type);
9893 ret = perf_try_init_event(pmu, event);
9899 list_for_each_entry_rcu(pmu, &pmus, entry) {
9900 ret = perf_try_init_event(pmu, event);
9904 if (ret != -ENOENT) {
9909 pmu = ERR_PTR(-ENOENT);
9911 srcu_read_unlock(&pmus_srcu, idx);
9916 static void attach_sb_event(struct perf_event *event)
9918 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9920 raw_spin_lock(&pel->lock);
9921 list_add_rcu(&event->sb_list, &pel->list);
9922 raw_spin_unlock(&pel->lock);
9926 * We keep a list of all !task (and therefore per-cpu) events
9927 * that need to receive side-band records.
9929 * This avoids having to scan all the various PMU per-cpu contexts
9932 static void account_pmu_sb_event(struct perf_event *event)
9934 if (is_sb_event(event))
9935 attach_sb_event(event);
9938 static void account_event_cpu(struct perf_event *event, int cpu)
9943 if (is_cgroup_event(event))
9944 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9947 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9948 static void account_freq_event_nohz(void)
9950 #ifdef CONFIG_NO_HZ_FULL
9951 /* Lock so we don't race with concurrent unaccount */
9952 spin_lock(&nr_freq_lock);
9953 if (atomic_inc_return(&nr_freq_events) == 1)
9954 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9955 spin_unlock(&nr_freq_lock);
9959 static void account_freq_event(void)
9961 if (tick_nohz_full_enabled())
9962 account_freq_event_nohz();
9964 atomic_inc(&nr_freq_events);
9968 static void account_event(struct perf_event *event)
9975 if (event->attach_state & PERF_ATTACH_TASK)
9977 if (event->attr.mmap || event->attr.mmap_data)
9978 atomic_inc(&nr_mmap_events);
9979 if (event->attr.comm)
9980 atomic_inc(&nr_comm_events);
9981 if (event->attr.namespaces)
9982 atomic_inc(&nr_namespaces_events);
9983 if (event->attr.task)
9984 atomic_inc(&nr_task_events);
9985 if (event->attr.freq)
9986 account_freq_event();
9987 if (event->attr.context_switch) {
9988 atomic_inc(&nr_switch_events);
9991 if (has_branch_stack(event))
9993 if (is_cgroup_event(event))
9998 * We need the mutex here because static_branch_enable()
9999 * must complete *before* the perf_sched_count increment
10002 if (atomic_inc_not_zero(&perf_sched_count))
10005 mutex_lock(&perf_sched_mutex);
10006 if (!atomic_read(&perf_sched_count)) {
10007 static_branch_enable(&perf_sched_events);
10009 * Guarantee that all CPUs observe they key change and
10010 * call the perf scheduling hooks before proceeding to
10011 * install events that need them.
10013 synchronize_sched();
10016 * Now that we have waited for the sync_sched(), allow further
10017 * increments to by-pass the mutex.
10019 atomic_inc(&perf_sched_count);
10020 mutex_unlock(&perf_sched_mutex);
10024 account_event_cpu(event, event->cpu);
10026 account_pmu_sb_event(event);
10030 * Allocate and initialize an event structure
10032 static struct perf_event *
10033 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10034 struct task_struct *task,
10035 struct perf_event *group_leader,
10036 struct perf_event *parent_event,
10037 perf_overflow_handler_t overflow_handler,
10038 void *context, int cgroup_fd)
10041 struct perf_event *event;
10042 struct hw_perf_event *hwc;
10043 long err = -EINVAL;
10045 if ((unsigned)cpu >= nr_cpu_ids) {
10046 if (!task || cpu != -1)
10047 return ERR_PTR(-EINVAL);
10050 event = kzalloc(sizeof(*event), GFP_KERNEL);
10052 return ERR_PTR(-ENOMEM);
10055 * Single events are their own group leaders, with an
10056 * empty sibling list:
10059 group_leader = event;
10061 mutex_init(&event->child_mutex);
10062 INIT_LIST_HEAD(&event->child_list);
10064 INIT_LIST_HEAD(&event->event_entry);
10065 INIT_LIST_HEAD(&event->sibling_list);
10066 INIT_LIST_HEAD(&event->active_list);
10067 init_event_group(event);
10068 INIT_LIST_HEAD(&event->rb_entry);
10069 INIT_LIST_HEAD(&event->active_entry);
10070 INIT_LIST_HEAD(&event->addr_filters.list);
10071 INIT_HLIST_NODE(&event->hlist_entry);
10074 init_waitqueue_head(&event->waitq);
10075 event->pending_disable = -1;
10076 init_irq_work(&event->pending, perf_pending_event);
10078 mutex_init(&event->mmap_mutex);
10079 raw_spin_lock_init(&event->addr_filters.lock);
10081 atomic_long_set(&event->refcount, 1);
10083 event->attr = *attr;
10084 event->group_leader = group_leader;
10088 event->parent = parent_event;
10090 event->ns = get_pid_ns(task_active_pid_ns(current));
10091 event->id = atomic64_inc_return(&perf_event_id);
10093 event->state = PERF_EVENT_STATE_INACTIVE;
10096 event->attach_state = PERF_ATTACH_TASK;
10098 * XXX pmu::event_init needs to know what task to account to
10099 * and we cannot use the ctx information because we need the
10100 * pmu before we get a ctx.
10102 get_task_struct(task);
10103 event->hw.target = task;
10106 event->clock = &local_clock;
10108 event->clock = parent_event->clock;
10110 if (!overflow_handler && parent_event) {
10111 overflow_handler = parent_event->overflow_handler;
10112 context = parent_event->overflow_handler_context;
10113 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10114 if (overflow_handler == bpf_overflow_handler) {
10115 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10117 if (IS_ERR(prog)) {
10118 err = PTR_ERR(prog);
10121 event->prog = prog;
10122 event->orig_overflow_handler =
10123 parent_event->orig_overflow_handler;
10128 if (overflow_handler) {
10129 event->overflow_handler = overflow_handler;
10130 event->overflow_handler_context = context;
10131 } else if (is_write_backward(event)){
10132 event->overflow_handler = perf_event_output_backward;
10133 event->overflow_handler_context = NULL;
10135 event->overflow_handler = perf_event_output_forward;
10136 event->overflow_handler_context = NULL;
10139 perf_event__state_init(event);
10144 hwc->sample_period = attr->sample_period;
10145 if (attr->freq && attr->sample_freq)
10146 hwc->sample_period = 1;
10147 hwc->last_period = hwc->sample_period;
10149 local64_set(&hwc->period_left, hwc->sample_period);
10152 * We currently do not support PERF_SAMPLE_READ on inherited events.
10153 * See perf_output_read().
10155 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10158 if (!has_branch_stack(event))
10159 event->attr.branch_sample_type = 0;
10161 if (cgroup_fd != -1) {
10162 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10167 pmu = perf_init_event(event);
10169 err = PTR_ERR(pmu);
10173 err = exclusive_event_init(event);
10177 if (has_addr_filter(event)) {
10178 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10179 sizeof(struct perf_addr_filter_range),
10181 if (!event->addr_filter_ranges) {
10187 * Clone the parent's vma offsets: they are valid until exec()
10188 * even if the mm is not shared with the parent.
10190 if (event->parent) {
10191 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10193 raw_spin_lock_irq(&ifh->lock);
10194 memcpy(event->addr_filter_ranges,
10195 event->parent->addr_filter_ranges,
10196 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10197 raw_spin_unlock_irq(&ifh->lock);
10200 /* force hw sync on the address filters */
10201 event->addr_filters_gen = 1;
10204 if (!event->parent) {
10205 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10206 err = get_callchain_buffers(attr->sample_max_stack);
10208 goto err_addr_filters;
10212 /* symmetric to unaccount_event() in _free_event() */
10213 account_event(event);
10218 kfree(event->addr_filter_ranges);
10221 exclusive_event_destroy(event);
10224 if (event->destroy)
10225 event->destroy(event);
10226 module_put(pmu->module);
10228 if (is_cgroup_event(event))
10229 perf_detach_cgroup(event);
10231 put_pid_ns(event->ns);
10232 if (event->hw.target)
10233 put_task_struct(event->hw.target);
10236 return ERR_PTR(err);
10239 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10240 struct perf_event_attr *attr)
10245 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
10249 * zero the full structure, so that a short copy will be nice.
10251 memset(attr, 0, sizeof(*attr));
10253 ret = get_user(size, &uattr->size);
10257 if (size > PAGE_SIZE) /* silly large */
10260 if (!size) /* abi compat */
10261 size = PERF_ATTR_SIZE_VER0;
10263 if (size < PERF_ATTR_SIZE_VER0)
10267 * If we're handed a bigger struct than we know of,
10268 * ensure all the unknown bits are 0 - i.e. new
10269 * user-space does not rely on any kernel feature
10270 * extensions we dont know about yet.
10272 if (size > sizeof(*attr)) {
10273 unsigned char __user *addr;
10274 unsigned char __user *end;
10277 addr = (void __user *)uattr + sizeof(*attr);
10278 end = (void __user *)uattr + size;
10280 for (; addr < end; addr++) {
10281 ret = get_user(val, addr);
10287 size = sizeof(*attr);
10290 ret = copy_from_user(attr, uattr, size);
10296 if (attr->__reserved_1)
10299 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10302 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10305 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10306 u64 mask = attr->branch_sample_type;
10308 /* only using defined bits */
10309 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10312 /* at least one branch bit must be set */
10313 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10316 /* propagate priv level, when not set for branch */
10317 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10319 /* exclude_kernel checked on syscall entry */
10320 if (!attr->exclude_kernel)
10321 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10323 if (!attr->exclude_user)
10324 mask |= PERF_SAMPLE_BRANCH_USER;
10326 if (!attr->exclude_hv)
10327 mask |= PERF_SAMPLE_BRANCH_HV;
10329 * adjust user setting (for HW filter setup)
10331 attr->branch_sample_type = mask;
10333 /* privileged levels capture (kernel, hv): check permissions */
10334 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10335 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10339 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10340 ret = perf_reg_validate(attr->sample_regs_user);
10345 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10346 if (!arch_perf_have_user_stack_dump())
10350 * We have __u32 type for the size, but so far
10351 * we can only use __u16 as maximum due to the
10352 * __u16 sample size limit.
10354 if (attr->sample_stack_user >= USHRT_MAX)
10356 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10360 if (!attr->sample_max_stack)
10361 attr->sample_max_stack = sysctl_perf_event_max_stack;
10363 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10364 ret = perf_reg_validate(attr->sample_regs_intr);
10369 put_user(sizeof(*attr), &uattr->size);
10375 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10377 struct ring_buffer *rb = NULL;
10383 /* don't allow circular references */
10384 if (event == output_event)
10388 * Don't allow cross-cpu buffers
10390 if (output_event->cpu != event->cpu)
10394 * If its not a per-cpu rb, it must be the same task.
10396 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10400 * Mixing clocks in the same buffer is trouble you don't need.
10402 if (output_event->clock != event->clock)
10406 * Either writing ring buffer from beginning or from end.
10407 * Mixing is not allowed.
10409 if (is_write_backward(output_event) != is_write_backward(event))
10413 * If both events generate aux data, they must be on the same PMU
10415 if (has_aux(event) && has_aux(output_event) &&
10416 event->pmu != output_event->pmu)
10420 mutex_lock(&event->mmap_mutex);
10421 /* Can't redirect output if we've got an active mmap() */
10422 if (atomic_read(&event->mmap_count))
10425 if (output_event) {
10426 /* get the rb we want to redirect to */
10427 rb = ring_buffer_get(output_event);
10432 ring_buffer_attach(event, rb);
10436 mutex_unlock(&event->mmap_mutex);
10442 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10448 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10451 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10453 bool nmi_safe = false;
10456 case CLOCK_MONOTONIC:
10457 event->clock = &ktime_get_mono_fast_ns;
10461 case CLOCK_MONOTONIC_RAW:
10462 event->clock = &ktime_get_raw_fast_ns;
10466 case CLOCK_REALTIME:
10467 event->clock = &ktime_get_real_ns;
10470 case CLOCK_BOOTTIME:
10471 event->clock = &ktime_get_boot_ns;
10475 event->clock = &ktime_get_tai_ns;
10482 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10489 * Variation on perf_event_ctx_lock_nested(), except we take two context
10492 static struct perf_event_context *
10493 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10494 struct perf_event_context *ctx)
10496 struct perf_event_context *gctx;
10500 gctx = READ_ONCE(group_leader->ctx);
10501 if (!atomic_inc_not_zero(&gctx->refcount)) {
10507 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10509 if (group_leader->ctx != gctx) {
10510 mutex_unlock(&ctx->mutex);
10511 mutex_unlock(&gctx->mutex);
10520 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10522 * @attr_uptr: event_id type attributes for monitoring/sampling
10525 * @group_fd: group leader event fd
10527 SYSCALL_DEFINE5(perf_event_open,
10528 struct perf_event_attr __user *, attr_uptr,
10529 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10531 struct perf_event *group_leader = NULL, *output_event = NULL;
10532 struct perf_event *event, *sibling;
10533 struct perf_event_attr attr;
10534 struct perf_event_context *ctx, *uninitialized_var(gctx);
10535 struct file *event_file = NULL;
10536 struct fd group = {NULL, 0};
10537 struct task_struct *task = NULL;
10540 int move_group = 0;
10542 int f_flags = O_RDWR;
10543 int cgroup_fd = -1;
10545 /* for future expandability... */
10546 if (flags & ~PERF_FLAG_ALL)
10549 err = perf_copy_attr(attr_uptr, &attr);
10553 if (!attr.exclude_kernel) {
10554 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10558 if (attr.namespaces) {
10559 if (!capable(CAP_SYS_ADMIN))
10564 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10567 if (attr.sample_period & (1ULL << 63))
10571 /* Only privileged users can get physical addresses */
10572 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10573 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10577 * In cgroup mode, the pid argument is used to pass the fd
10578 * opened to the cgroup directory in cgroupfs. The cpu argument
10579 * designates the cpu on which to monitor threads from that
10582 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10585 if (flags & PERF_FLAG_FD_CLOEXEC)
10586 f_flags |= O_CLOEXEC;
10588 event_fd = get_unused_fd_flags(f_flags);
10592 if (group_fd != -1) {
10593 err = perf_fget_light(group_fd, &group);
10596 group_leader = group.file->private_data;
10597 if (flags & PERF_FLAG_FD_OUTPUT)
10598 output_event = group_leader;
10599 if (flags & PERF_FLAG_FD_NO_GROUP)
10600 group_leader = NULL;
10603 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10604 task = find_lively_task_by_vpid(pid);
10605 if (IS_ERR(task)) {
10606 err = PTR_ERR(task);
10611 if (task && group_leader &&
10612 group_leader->attr.inherit != attr.inherit) {
10618 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10623 * Reuse ptrace permission checks for now.
10625 * We must hold cred_guard_mutex across this and any potential
10626 * perf_install_in_context() call for this new event to
10627 * serialize against exec() altering our credentials (and the
10628 * perf_event_exit_task() that could imply).
10631 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10635 if (flags & PERF_FLAG_PID_CGROUP)
10638 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10639 NULL, NULL, cgroup_fd);
10640 if (IS_ERR(event)) {
10641 err = PTR_ERR(event);
10645 if (is_sampling_event(event)) {
10646 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10653 * Special case software events and allow them to be part of
10654 * any hardware group.
10658 if (attr.use_clockid) {
10659 err = perf_event_set_clock(event, attr.clockid);
10664 if (pmu->task_ctx_nr == perf_sw_context)
10665 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10667 if (group_leader) {
10668 if (is_software_event(event) &&
10669 !in_software_context(group_leader)) {
10671 * If the event is a sw event, but the group_leader
10672 * is on hw context.
10674 * Allow the addition of software events to hw
10675 * groups, this is safe because software events
10676 * never fail to schedule.
10678 pmu = group_leader->ctx->pmu;
10679 } else if (!is_software_event(event) &&
10680 is_software_event(group_leader) &&
10681 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10683 * In case the group is a pure software group, and we
10684 * try to add a hardware event, move the whole group to
10685 * the hardware context.
10692 * Get the target context (task or percpu):
10694 ctx = find_get_context(pmu, task, event);
10696 err = PTR_ERR(ctx);
10701 * Look up the group leader (we will attach this event to it):
10703 if (group_leader) {
10707 * Do not allow a recursive hierarchy (this new sibling
10708 * becoming part of another group-sibling):
10710 if (group_leader->group_leader != group_leader)
10713 /* All events in a group should have the same clock */
10714 if (group_leader->clock != event->clock)
10718 * Make sure we're both events for the same CPU;
10719 * grouping events for different CPUs is broken; since
10720 * you can never concurrently schedule them anyhow.
10722 if (group_leader->cpu != event->cpu)
10726 * Make sure we're both on the same task, or both
10729 if (group_leader->ctx->task != ctx->task)
10733 * Do not allow to attach to a group in a different task
10734 * or CPU context. If we're moving SW events, we'll fix
10735 * this up later, so allow that.
10737 if (!move_group && group_leader->ctx != ctx)
10741 * Only a group leader can be exclusive or pinned
10743 if (attr.exclusive || attr.pinned)
10747 if (output_event) {
10748 err = perf_event_set_output(event, output_event);
10753 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10755 if (IS_ERR(event_file)) {
10756 err = PTR_ERR(event_file);
10762 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10764 if (gctx->task == TASK_TOMBSTONE) {
10770 * Check if we raced against another sys_perf_event_open() call
10771 * moving the software group underneath us.
10773 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10775 * If someone moved the group out from under us, check
10776 * if this new event wound up on the same ctx, if so
10777 * its the regular !move_group case, otherwise fail.
10783 perf_event_ctx_unlock(group_leader, gctx);
10789 * Failure to create exclusive events returns -EBUSY.
10792 if (!exclusive_event_installable(group_leader, ctx))
10795 for_each_sibling_event(sibling, group_leader) {
10796 if (!exclusive_event_installable(sibling, ctx))
10800 mutex_lock(&ctx->mutex);
10803 if (ctx->task == TASK_TOMBSTONE) {
10808 if (!perf_event_validate_size(event)) {
10815 * Check if the @cpu we're creating an event for is online.
10817 * We use the perf_cpu_context::ctx::mutex to serialize against
10818 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10820 struct perf_cpu_context *cpuctx =
10821 container_of(ctx, struct perf_cpu_context, ctx);
10823 if (!cpuctx->online) {
10831 * Must be under the same ctx::mutex as perf_install_in_context(),
10832 * because we need to serialize with concurrent event creation.
10834 if (!exclusive_event_installable(event, ctx)) {
10839 WARN_ON_ONCE(ctx->parent_ctx);
10842 * This is the point on no return; we cannot fail hereafter. This is
10843 * where we start modifying current state.
10848 * See perf_event_ctx_lock() for comments on the details
10849 * of swizzling perf_event::ctx.
10851 perf_remove_from_context(group_leader, 0);
10854 for_each_sibling_event(sibling, group_leader) {
10855 perf_remove_from_context(sibling, 0);
10860 * Wait for everybody to stop referencing the events through
10861 * the old lists, before installing it on new lists.
10866 * Install the group siblings before the group leader.
10868 * Because a group leader will try and install the entire group
10869 * (through the sibling list, which is still in-tact), we can
10870 * end up with siblings installed in the wrong context.
10872 * By installing siblings first we NO-OP because they're not
10873 * reachable through the group lists.
10875 for_each_sibling_event(sibling, group_leader) {
10876 perf_event__state_init(sibling);
10877 perf_install_in_context(ctx, sibling, sibling->cpu);
10882 * Removing from the context ends up with disabled
10883 * event. What we want here is event in the initial
10884 * startup state, ready to be add into new context.
10886 perf_event__state_init(group_leader);
10887 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10892 * Precalculate sample_data sizes; do while holding ctx::mutex such
10893 * that we're serialized against further additions and before
10894 * perf_install_in_context() which is the point the event is active and
10895 * can use these values.
10897 perf_event__header_size(event);
10898 perf_event__id_header_size(event);
10900 event->owner = current;
10902 perf_install_in_context(ctx, event, event->cpu);
10903 perf_unpin_context(ctx);
10906 perf_event_ctx_unlock(group_leader, gctx);
10907 mutex_unlock(&ctx->mutex);
10910 mutex_unlock(&task->signal->cred_guard_mutex);
10911 put_task_struct(task);
10914 mutex_lock(¤t->perf_event_mutex);
10915 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10916 mutex_unlock(¤t->perf_event_mutex);
10919 * Drop the reference on the group_event after placing the
10920 * new event on the sibling_list. This ensures destruction
10921 * of the group leader will find the pointer to itself in
10922 * perf_group_detach().
10925 fd_install(event_fd, event_file);
10930 perf_event_ctx_unlock(group_leader, gctx);
10931 mutex_unlock(&ctx->mutex);
10935 perf_unpin_context(ctx);
10939 * If event_file is set, the fput() above will have called ->release()
10940 * and that will take care of freeing the event.
10946 mutex_unlock(&task->signal->cred_guard_mutex);
10949 put_task_struct(task);
10953 put_unused_fd(event_fd);
10958 * perf_event_create_kernel_counter
10960 * @attr: attributes of the counter to create
10961 * @cpu: cpu in which the counter is bound
10962 * @task: task to profile (NULL for percpu)
10964 struct perf_event *
10965 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10966 struct task_struct *task,
10967 perf_overflow_handler_t overflow_handler,
10970 struct perf_event_context *ctx;
10971 struct perf_event *event;
10975 * Get the target context (task or percpu):
10978 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10979 overflow_handler, context, -1);
10980 if (IS_ERR(event)) {
10981 err = PTR_ERR(event);
10985 /* Mark owner so we could distinguish it from user events. */
10986 event->owner = TASK_TOMBSTONE;
10988 ctx = find_get_context(event->pmu, task, event);
10990 err = PTR_ERR(ctx);
10994 WARN_ON_ONCE(ctx->parent_ctx);
10995 mutex_lock(&ctx->mutex);
10996 if (ctx->task == TASK_TOMBSTONE) {
11003 * Check if the @cpu we're creating an event for is online.
11005 * We use the perf_cpu_context::ctx::mutex to serialize against
11006 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11008 struct perf_cpu_context *cpuctx =
11009 container_of(ctx, struct perf_cpu_context, ctx);
11010 if (!cpuctx->online) {
11016 if (!exclusive_event_installable(event, ctx)) {
11021 perf_install_in_context(ctx, event, event->cpu);
11022 perf_unpin_context(ctx);
11023 mutex_unlock(&ctx->mutex);
11028 mutex_unlock(&ctx->mutex);
11029 perf_unpin_context(ctx);
11034 return ERR_PTR(err);
11036 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11038 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11040 struct perf_event_context *src_ctx;
11041 struct perf_event_context *dst_ctx;
11042 struct perf_event *event, *tmp;
11045 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11046 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11049 * See perf_event_ctx_lock() for comments on the details
11050 * of swizzling perf_event::ctx.
11052 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11053 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11055 perf_remove_from_context(event, 0);
11056 unaccount_event_cpu(event, src_cpu);
11058 list_add(&event->migrate_entry, &events);
11062 * Wait for the events to quiesce before re-instating them.
11067 * Re-instate events in 2 passes.
11069 * Skip over group leaders and only install siblings on this first
11070 * pass, siblings will not get enabled without a leader, however a
11071 * leader will enable its siblings, even if those are still on the old
11074 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11075 if (event->group_leader == event)
11078 list_del(&event->migrate_entry);
11079 if (event->state >= PERF_EVENT_STATE_OFF)
11080 event->state = PERF_EVENT_STATE_INACTIVE;
11081 account_event_cpu(event, dst_cpu);
11082 perf_install_in_context(dst_ctx, event, dst_cpu);
11087 * Once all the siblings are setup properly, install the group leaders
11090 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11091 list_del(&event->migrate_entry);
11092 if (event->state >= PERF_EVENT_STATE_OFF)
11093 event->state = PERF_EVENT_STATE_INACTIVE;
11094 account_event_cpu(event, dst_cpu);
11095 perf_install_in_context(dst_ctx, event, dst_cpu);
11098 mutex_unlock(&dst_ctx->mutex);
11099 mutex_unlock(&src_ctx->mutex);
11101 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11103 static void sync_child_event(struct perf_event *child_event,
11104 struct task_struct *child)
11106 struct perf_event *parent_event = child_event->parent;
11109 if (child_event->attr.inherit_stat)
11110 perf_event_read_event(child_event, child);
11112 child_val = perf_event_count(child_event);
11115 * Add back the child's count to the parent's count:
11117 atomic64_add(child_val, &parent_event->child_count);
11118 atomic64_add(child_event->total_time_enabled,
11119 &parent_event->child_total_time_enabled);
11120 atomic64_add(child_event->total_time_running,
11121 &parent_event->child_total_time_running);
11125 perf_event_exit_event(struct perf_event *child_event,
11126 struct perf_event_context *child_ctx,
11127 struct task_struct *child)
11129 struct perf_event *parent_event = child_event->parent;
11132 * Do not destroy the 'original' grouping; because of the context
11133 * switch optimization the original events could've ended up in a
11134 * random child task.
11136 * If we were to destroy the original group, all group related
11137 * operations would cease to function properly after this random
11140 * Do destroy all inherited groups, we don't care about those
11141 * and being thorough is better.
11143 raw_spin_lock_irq(&child_ctx->lock);
11144 WARN_ON_ONCE(child_ctx->is_active);
11147 perf_group_detach(child_event);
11148 list_del_event(child_event, child_ctx);
11149 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11150 raw_spin_unlock_irq(&child_ctx->lock);
11153 * Parent events are governed by their filedesc, retain them.
11155 if (!parent_event) {
11156 perf_event_wakeup(child_event);
11160 * Child events can be cleaned up.
11163 sync_child_event(child_event, child);
11166 * Remove this event from the parent's list
11168 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11169 mutex_lock(&parent_event->child_mutex);
11170 list_del_init(&child_event->child_list);
11171 mutex_unlock(&parent_event->child_mutex);
11174 * Kick perf_poll() for is_event_hup().
11176 perf_event_wakeup(parent_event);
11177 free_event(child_event);
11178 put_event(parent_event);
11181 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11183 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11184 struct perf_event *child_event, *next;
11186 WARN_ON_ONCE(child != current);
11188 child_ctx = perf_pin_task_context(child, ctxn);
11193 * In order to reduce the amount of tricky in ctx tear-down, we hold
11194 * ctx::mutex over the entire thing. This serializes against almost
11195 * everything that wants to access the ctx.
11197 * The exception is sys_perf_event_open() /
11198 * perf_event_create_kernel_count() which does find_get_context()
11199 * without ctx::mutex (it cannot because of the move_group double mutex
11200 * lock thing). See the comments in perf_install_in_context().
11202 mutex_lock(&child_ctx->mutex);
11205 * In a single ctx::lock section, de-schedule the events and detach the
11206 * context from the task such that we cannot ever get it scheduled back
11209 raw_spin_lock_irq(&child_ctx->lock);
11210 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11213 * Now that the context is inactive, destroy the task <-> ctx relation
11214 * and mark the context dead.
11216 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11217 put_ctx(child_ctx); /* cannot be last */
11218 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11219 put_task_struct(current); /* cannot be last */
11221 clone_ctx = unclone_ctx(child_ctx);
11222 raw_spin_unlock_irq(&child_ctx->lock);
11225 put_ctx(clone_ctx);
11228 * Report the task dead after unscheduling the events so that we
11229 * won't get any samples after PERF_RECORD_EXIT. We can however still
11230 * get a few PERF_RECORD_READ events.
11232 perf_event_task(child, child_ctx, 0);
11234 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11235 perf_event_exit_event(child_event, child_ctx, child);
11237 mutex_unlock(&child_ctx->mutex);
11239 put_ctx(child_ctx);
11243 * When a child task exits, feed back event values to parent events.
11245 * Can be called with cred_guard_mutex held when called from
11246 * install_exec_creds().
11248 void perf_event_exit_task(struct task_struct *child)
11250 struct perf_event *event, *tmp;
11253 mutex_lock(&child->perf_event_mutex);
11254 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11256 list_del_init(&event->owner_entry);
11259 * Ensure the list deletion is visible before we clear
11260 * the owner, closes a race against perf_release() where
11261 * we need to serialize on the owner->perf_event_mutex.
11263 smp_store_release(&event->owner, NULL);
11265 mutex_unlock(&child->perf_event_mutex);
11267 for_each_task_context_nr(ctxn)
11268 perf_event_exit_task_context(child, ctxn);
11271 * The perf_event_exit_task_context calls perf_event_task
11272 * with child's task_ctx, which generates EXIT events for
11273 * child contexts and sets child->perf_event_ctxp[] to NULL.
11274 * At this point we need to send EXIT events to cpu contexts.
11276 perf_event_task(child, NULL, 0);
11279 static void perf_free_event(struct perf_event *event,
11280 struct perf_event_context *ctx)
11282 struct perf_event *parent = event->parent;
11284 if (WARN_ON_ONCE(!parent))
11287 mutex_lock(&parent->child_mutex);
11288 list_del_init(&event->child_list);
11289 mutex_unlock(&parent->child_mutex);
11293 raw_spin_lock_irq(&ctx->lock);
11294 perf_group_detach(event);
11295 list_del_event(event, ctx);
11296 raw_spin_unlock_irq(&ctx->lock);
11301 * Free a context as created by inheritance by perf_event_init_task() below,
11302 * used by fork() in case of fail.
11304 * Even though the task has never lived, the context and events have been
11305 * exposed through the child_list, so we must take care tearing it all down.
11307 void perf_event_free_task(struct task_struct *task)
11309 struct perf_event_context *ctx;
11310 struct perf_event *event, *tmp;
11313 for_each_task_context_nr(ctxn) {
11314 ctx = task->perf_event_ctxp[ctxn];
11318 mutex_lock(&ctx->mutex);
11319 raw_spin_lock_irq(&ctx->lock);
11321 * Destroy the task <-> ctx relation and mark the context dead.
11323 * This is important because even though the task hasn't been
11324 * exposed yet the context has been (through child_list).
11326 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11327 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11328 put_task_struct(task); /* cannot be last */
11329 raw_spin_unlock_irq(&ctx->lock);
11331 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11332 perf_free_event(event, ctx);
11334 mutex_unlock(&ctx->mutex);
11337 * perf_event_release_kernel() could've stolen some of our
11338 * child events and still have them on its free_list. In that
11339 * case we must wait for these events to have been freed (in
11340 * particular all their references to this task must've been
11343 * Without this copy_process() will unconditionally free this
11344 * task (irrespective of its reference count) and
11345 * _free_event()'s put_task_struct(event->hw.target) will be a
11348 * Wait for all events to drop their context reference.
11350 wait_var_event(&ctx->refcount, atomic_read(&ctx->refcount) == 1);
11351 put_ctx(ctx); /* must be last */
11355 void perf_event_delayed_put(struct task_struct *task)
11359 for_each_task_context_nr(ctxn)
11360 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11363 struct file *perf_event_get(unsigned int fd)
11367 file = fget_raw(fd);
11369 return ERR_PTR(-EBADF);
11371 if (file->f_op != &perf_fops) {
11373 return ERR_PTR(-EBADF);
11379 const struct perf_event *perf_get_event(struct file *file)
11381 if (file->f_op != &perf_fops)
11382 return ERR_PTR(-EINVAL);
11384 return file->private_data;
11387 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11390 return ERR_PTR(-EINVAL);
11392 return &event->attr;
11396 * Inherit an event from parent task to child task.
11399 * - valid pointer on success
11400 * - NULL for orphaned events
11401 * - IS_ERR() on error
11403 static struct perf_event *
11404 inherit_event(struct perf_event *parent_event,
11405 struct task_struct *parent,
11406 struct perf_event_context *parent_ctx,
11407 struct task_struct *child,
11408 struct perf_event *group_leader,
11409 struct perf_event_context *child_ctx)
11411 enum perf_event_state parent_state = parent_event->state;
11412 struct perf_event *child_event;
11413 unsigned long flags;
11416 * Instead of creating recursive hierarchies of events,
11417 * we link inherited events back to the original parent,
11418 * which has a filp for sure, which we use as the reference
11421 if (parent_event->parent)
11422 parent_event = parent_event->parent;
11424 child_event = perf_event_alloc(&parent_event->attr,
11427 group_leader, parent_event,
11429 if (IS_ERR(child_event))
11430 return child_event;
11433 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11434 !child_ctx->task_ctx_data) {
11435 struct pmu *pmu = child_event->pmu;
11437 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11439 if (!child_ctx->task_ctx_data) {
11440 free_event(child_event);
11441 return ERR_PTR(-ENOMEM);
11446 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11447 * must be under the same lock in order to serialize against
11448 * perf_event_release_kernel(), such that either we must observe
11449 * is_orphaned_event() or they will observe us on the child_list.
11451 mutex_lock(&parent_event->child_mutex);
11452 if (is_orphaned_event(parent_event) ||
11453 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11454 mutex_unlock(&parent_event->child_mutex);
11455 /* task_ctx_data is freed with child_ctx */
11456 free_event(child_event);
11460 get_ctx(child_ctx);
11463 * Make the child state follow the state of the parent event,
11464 * not its attr.disabled bit. We hold the parent's mutex,
11465 * so we won't race with perf_event_{en, dis}able_family.
11467 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11468 child_event->state = PERF_EVENT_STATE_INACTIVE;
11470 child_event->state = PERF_EVENT_STATE_OFF;
11472 if (parent_event->attr.freq) {
11473 u64 sample_period = parent_event->hw.sample_period;
11474 struct hw_perf_event *hwc = &child_event->hw;
11476 hwc->sample_period = sample_period;
11477 hwc->last_period = sample_period;
11479 local64_set(&hwc->period_left, sample_period);
11482 child_event->ctx = child_ctx;
11483 child_event->overflow_handler = parent_event->overflow_handler;
11484 child_event->overflow_handler_context
11485 = parent_event->overflow_handler_context;
11488 * Precalculate sample_data sizes
11490 perf_event__header_size(child_event);
11491 perf_event__id_header_size(child_event);
11494 * Link it up in the child's context:
11496 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11497 add_event_to_ctx(child_event, child_ctx);
11498 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11501 * Link this into the parent event's child list
11503 list_add_tail(&child_event->child_list, &parent_event->child_list);
11504 mutex_unlock(&parent_event->child_mutex);
11506 return child_event;
11510 * Inherits an event group.
11512 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11513 * This matches with perf_event_release_kernel() removing all child events.
11519 static int inherit_group(struct perf_event *parent_event,
11520 struct task_struct *parent,
11521 struct perf_event_context *parent_ctx,
11522 struct task_struct *child,
11523 struct perf_event_context *child_ctx)
11525 struct perf_event *leader;
11526 struct perf_event *sub;
11527 struct perf_event *child_ctr;
11529 leader = inherit_event(parent_event, parent, parent_ctx,
11530 child, NULL, child_ctx);
11531 if (IS_ERR(leader))
11532 return PTR_ERR(leader);
11534 * @leader can be NULL here because of is_orphaned_event(). In this
11535 * case inherit_event() will create individual events, similar to what
11536 * perf_group_detach() would do anyway.
11538 for_each_sibling_event(sub, parent_event) {
11539 child_ctr = inherit_event(sub, parent, parent_ctx,
11540 child, leader, child_ctx);
11541 if (IS_ERR(child_ctr))
11542 return PTR_ERR(child_ctr);
11548 * Creates the child task context and tries to inherit the event-group.
11550 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11551 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11552 * consistent with perf_event_release_kernel() removing all child events.
11559 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11560 struct perf_event_context *parent_ctx,
11561 struct task_struct *child, int ctxn,
11562 int *inherited_all)
11565 struct perf_event_context *child_ctx;
11567 if (!event->attr.inherit) {
11568 *inherited_all = 0;
11572 child_ctx = child->perf_event_ctxp[ctxn];
11575 * This is executed from the parent task context, so
11576 * inherit events that have been marked for cloning.
11577 * First allocate and initialize a context for the
11580 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11584 child->perf_event_ctxp[ctxn] = child_ctx;
11587 ret = inherit_group(event, parent, parent_ctx,
11591 *inherited_all = 0;
11597 * Initialize the perf_event context in task_struct
11599 static int perf_event_init_context(struct task_struct *child, int ctxn)
11601 struct perf_event_context *child_ctx, *parent_ctx;
11602 struct perf_event_context *cloned_ctx;
11603 struct perf_event *event;
11604 struct task_struct *parent = current;
11605 int inherited_all = 1;
11606 unsigned long flags;
11609 if (likely(!parent->perf_event_ctxp[ctxn]))
11613 * If the parent's context is a clone, pin it so it won't get
11614 * swapped under us.
11616 parent_ctx = perf_pin_task_context(parent, ctxn);
11621 * No need to check if parent_ctx != NULL here; since we saw
11622 * it non-NULL earlier, the only reason for it to become NULL
11623 * is if we exit, and since we're currently in the middle of
11624 * a fork we can't be exiting at the same time.
11628 * Lock the parent list. No need to lock the child - not PID
11629 * hashed yet and not running, so nobody can access it.
11631 mutex_lock(&parent_ctx->mutex);
11634 * We dont have to disable NMIs - we are only looking at
11635 * the list, not manipulating it:
11637 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11638 ret = inherit_task_group(event, parent, parent_ctx,
11639 child, ctxn, &inherited_all);
11645 * We can't hold ctx->lock when iterating the ->flexible_group list due
11646 * to allocations, but we need to prevent rotation because
11647 * rotate_ctx() will change the list from interrupt context.
11649 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11650 parent_ctx->rotate_disable = 1;
11651 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11653 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11654 ret = inherit_task_group(event, parent, parent_ctx,
11655 child, ctxn, &inherited_all);
11660 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11661 parent_ctx->rotate_disable = 0;
11663 child_ctx = child->perf_event_ctxp[ctxn];
11665 if (child_ctx && inherited_all) {
11667 * Mark the child context as a clone of the parent
11668 * context, or of whatever the parent is a clone of.
11670 * Note that if the parent is a clone, the holding of
11671 * parent_ctx->lock avoids it from being uncloned.
11673 cloned_ctx = parent_ctx->parent_ctx;
11675 child_ctx->parent_ctx = cloned_ctx;
11676 child_ctx->parent_gen = parent_ctx->parent_gen;
11678 child_ctx->parent_ctx = parent_ctx;
11679 child_ctx->parent_gen = parent_ctx->generation;
11681 get_ctx(child_ctx->parent_ctx);
11684 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11686 mutex_unlock(&parent_ctx->mutex);
11688 perf_unpin_context(parent_ctx);
11689 put_ctx(parent_ctx);
11695 * Initialize the perf_event context in task_struct
11697 int perf_event_init_task(struct task_struct *child)
11701 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11702 mutex_init(&child->perf_event_mutex);
11703 INIT_LIST_HEAD(&child->perf_event_list);
11705 for_each_task_context_nr(ctxn) {
11706 ret = perf_event_init_context(child, ctxn);
11708 perf_event_free_task(child);
11716 static void __init perf_event_init_all_cpus(void)
11718 struct swevent_htable *swhash;
11721 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11723 for_each_possible_cpu(cpu) {
11724 swhash = &per_cpu(swevent_htable, cpu);
11725 mutex_init(&swhash->hlist_mutex);
11726 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11728 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11729 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11731 #ifdef CONFIG_CGROUP_PERF
11732 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11734 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11738 void perf_swevent_init_cpu(unsigned int cpu)
11740 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11742 mutex_lock(&swhash->hlist_mutex);
11743 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11744 struct swevent_hlist *hlist;
11746 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11748 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11750 mutex_unlock(&swhash->hlist_mutex);
11753 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11754 static void __perf_event_exit_context(void *__info)
11756 struct perf_event_context *ctx = __info;
11757 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11758 struct perf_event *event;
11760 raw_spin_lock(&ctx->lock);
11761 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11762 list_for_each_entry(event, &ctx->event_list, event_entry)
11763 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11764 raw_spin_unlock(&ctx->lock);
11767 static void perf_event_exit_cpu_context(int cpu)
11769 struct perf_cpu_context *cpuctx;
11770 struct perf_event_context *ctx;
11773 mutex_lock(&pmus_lock);
11774 list_for_each_entry(pmu, &pmus, entry) {
11775 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11776 ctx = &cpuctx->ctx;
11778 mutex_lock(&ctx->mutex);
11779 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11780 cpuctx->online = 0;
11781 mutex_unlock(&ctx->mutex);
11783 cpumask_clear_cpu(cpu, perf_online_mask);
11784 mutex_unlock(&pmus_lock);
11788 static void perf_event_exit_cpu_context(int cpu) { }
11792 int perf_event_init_cpu(unsigned int cpu)
11794 struct perf_cpu_context *cpuctx;
11795 struct perf_event_context *ctx;
11798 perf_swevent_init_cpu(cpu);
11800 mutex_lock(&pmus_lock);
11801 cpumask_set_cpu(cpu, perf_online_mask);
11802 list_for_each_entry(pmu, &pmus, entry) {
11803 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11804 ctx = &cpuctx->ctx;
11806 mutex_lock(&ctx->mutex);
11807 cpuctx->online = 1;
11808 mutex_unlock(&ctx->mutex);
11810 mutex_unlock(&pmus_lock);
11815 int perf_event_exit_cpu(unsigned int cpu)
11817 perf_event_exit_cpu_context(cpu);
11822 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11826 for_each_online_cpu(cpu)
11827 perf_event_exit_cpu(cpu);
11833 * Run the perf reboot notifier at the very last possible moment so that
11834 * the generic watchdog code runs as long as possible.
11836 static struct notifier_block perf_reboot_notifier = {
11837 .notifier_call = perf_reboot,
11838 .priority = INT_MIN,
11841 void __init perf_event_init(void)
11845 idr_init(&pmu_idr);
11847 perf_event_init_all_cpus();
11848 init_srcu_struct(&pmus_srcu);
11849 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11850 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11851 perf_pmu_register(&perf_task_clock, NULL, -1);
11852 perf_tp_register();
11853 perf_event_init_cpu(smp_processor_id());
11854 register_reboot_notifier(&perf_reboot_notifier);
11856 ret = init_hw_breakpoint();
11857 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11860 * Build time assertion that we keep the data_head at the intended
11861 * location. IOW, validation we got the __reserved[] size right.
11863 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11867 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11870 struct perf_pmu_events_attr *pmu_attr =
11871 container_of(attr, struct perf_pmu_events_attr, attr);
11873 if (pmu_attr->event_str)
11874 return sprintf(page, "%s\n", pmu_attr->event_str);
11878 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11880 static int __init perf_event_sysfs_init(void)
11885 mutex_lock(&pmus_lock);
11887 ret = bus_register(&pmu_bus);
11891 list_for_each_entry(pmu, &pmus, entry) {
11892 if (!pmu->name || pmu->type < 0)
11895 ret = pmu_dev_alloc(pmu);
11896 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11898 pmu_bus_running = 1;
11902 mutex_unlock(&pmus_lock);
11906 device_initcall(perf_event_sysfs_init);
11908 #ifdef CONFIG_CGROUP_PERF
11909 static struct cgroup_subsys_state *
11910 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11912 struct perf_cgroup *jc;
11914 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11916 return ERR_PTR(-ENOMEM);
11918 jc->info = alloc_percpu(struct perf_cgroup_info);
11921 return ERR_PTR(-ENOMEM);
11927 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11929 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11931 free_percpu(jc->info);
11935 static int __perf_cgroup_move(void *info)
11937 struct task_struct *task = info;
11939 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11944 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11946 struct task_struct *task;
11947 struct cgroup_subsys_state *css;
11949 cgroup_taskset_for_each(task, css, tset)
11950 task_function_call(task, __perf_cgroup_move, task);
11953 struct cgroup_subsys perf_event_cgrp_subsys = {
11954 .css_alloc = perf_cgroup_css_alloc,
11955 .css_free = perf_cgroup_css_free,
11956 .attach = perf_cgroup_attach,
11958 * Implicitly enable on dfl hierarchy so that perf events can
11959 * always be filtered by cgroup2 path as long as perf_event
11960 * controller is not mounted on a legacy hierarchy.
11962 .implicit_on_dfl = true,
11965 #endif /* CONFIG_CGROUP_PERF */