1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/cgroup.h>
37 #include <linux/perf_event.h>
38 #include <linux/trace_events.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/module.h>
42 #include <linux/mman.h>
43 #include <linux/compat.h>
44 #include <linux/bpf.h>
45 #include <linux/filter.h>
46 #include <linux/namei.h>
47 #include <linux/parser.h>
48 #include <linux/sched/clock.h>
49 #include <linux/sched/mm.h>
50 #include <linux/proc_ns.h>
51 #include <linux/mount.h>
55 #include <asm/irq_regs.h>
57 typedef int (*remote_function_f)(void *);
59 struct remote_function_call {
60 struct task_struct *p;
61 remote_function_f func;
66 static void remote_function(void *data)
68 struct remote_function_call *tfc = data;
69 struct task_struct *p = tfc->p;
73 if (task_cpu(p) != smp_processor_id())
77 * Now that we're on right CPU with IRQs disabled, we can test
78 * if we hit the right task without races.
81 tfc->ret = -ESRCH; /* No such (running) process */
86 tfc->ret = tfc->func(tfc->info);
90 * task_function_call - call a function on the cpu on which a task runs
91 * @p: the task to evaluate
92 * @func: the function to be called
93 * @info: the function call argument
95 * Calls the function @func when the task is currently running. This might
96 * be on the current CPU, which just calls the function directly
98 * returns: @func return value, or
99 * -ESRCH - when the process isn't running
100 * -EAGAIN - when the process moved away
103 task_function_call(struct task_struct *p, remote_function_f func, void *info)
105 struct remote_function_call data = {
114 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
117 } while (ret == -EAGAIN);
123 * cpu_function_call - call a function on the cpu
124 * @func: the function to be called
125 * @info: the function call argument
127 * Calls the function @func on the remote cpu.
129 * returns: @func return value or -ENXIO when the cpu is offline
131 static int cpu_function_call(int cpu, remote_function_f func, void *info)
133 struct remote_function_call data = {
137 .ret = -ENXIO, /* No such CPU */
140 smp_call_function_single(cpu, remote_function, &data, 1);
145 static inline struct perf_cpu_context *
146 __get_cpu_context(struct perf_event_context *ctx)
148 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
151 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
152 struct perf_event_context *ctx)
154 raw_spin_lock(&cpuctx->ctx.lock);
156 raw_spin_lock(&ctx->lock);
159 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
160 struct perf_event_context *ctx)
163 raw_spin_unlock(&ctx->lock);
164 raw_spin_unlock(&cpuctx->ctx.lock);
167 #define TASK_TOMBSTONE ((void *)-1L)
169 static bool is_kernel_event(struct perf_event *event)
171 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
175 * On task ctx scheduling...
177 * When !ctx->nr_events a task context will not be scheduled. This means
178 * we can disable the scheduler hooks (for performance) without leaving
179 * pending task ctx state.
181 * This however results in two special cases:
183 * - removing the last event from a task ctx; this is relatively straight
184 * forward and is done in __perf_remove_from_context.
186 * - adding the first event to a task ctx; this is tricky because we cannot
187 * rely on ctx->is_active and therefore cannot use event_function_call().
188 * See perf_install_in_context().
190 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
193 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
194 struct perf_event_context *, void *);
196 struct event_function_struct {
197 struct perf_event *event;
202 static int event_function(void *info)
204 struct event_function_struct *efs = info;
205 struct perf_event *event = efs->event;
206 struct perf_event_context *ctx = event->ctx;
207 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
208 struct perf_event_context *task_ctx = cpuctx->task_ctx;
211 lockdep_assert_irqs_disabled();
213 perf_ctx_lock(cpuctx, task_ctx);
215 * Since we do the IPI call without holding ctx->lock things can have
216 * changed, double check we hit the task we set out to hit.
219 if (ctx->task != current) {
225 * We only use event_function_call() on established contexts,
226 * and event_function() is only ever called when active (or
227 * rather, we'll have bailed in task_function_call() or the
228 * above ctx->task != current test), therefore we must have
229 * ctx->is_active here.
231 WARN_ON_ONCE(!ctx->is_active);
233 * And since we have ctx->is_active, cpuctx->task_ctx must
236 WARN_ON_ONCE(task_ctx != ctx);
238 WARN_ON_ONCE(&cpuctx->ctx != ctx);
241 efs->func(event, cpuctx, ctx, efs->data);
243 perf_ctx_unlock(cpuctx, task_ctx);
248 static void event_function_call(struct perf_event *event, event_f func, void *data)
250 struct perf_event_context *ctx = event->ctx;
251 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
252 struct event_function_struct efs = {
258 if (!event->parent) {
260 * If this is a !child event, we must hold ctx::mutex to
261 * stabilize the the event->ctx relation. See
262 * perf_event_ctx_lock().
264 lockdep_assert_held(&ctx->mutex);
268 cpu_function_call(event->cpu, event_function, &efs);
272 if (task == TASK_TOMBSTONE)
276 if (!task_function_call(task, event_function, &efs))
279 raw_spin_lock_irq(&ctx->lock);
281 * Reload the task pointer, it might have been changed by
282 * a concurrent perf_event_context_sched_out().
285 if (task == TASK_TOMBSTONE) {
286 raw_spin_unlock_irq(&ctx->lock);
289 if (ctx->is_active) {
290 raw_spin_unlock_irq(&ctx->lock);
293 func(event, NULL, ctx, data);
294 raw_spin_unlock_irq(&ctx->lock);
298 * Similar to event_function_call() + event_function(), but hard assumes IRQs
299 * are already disabled and we're on the right CPU.
301 static void event_function_local(struct perf_event *event, event_f func, void *data)
303 struct perf_event_context *ctx = event->ctx;
304 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
305 struct task_struct *task = READ_ONCE(ctx->task);
306 struct perf_event_context *task_ctx = NULL;
308 lockdep_assert_irqs_disabled();
311 if (task == TASK_TOMBSTONE)
317 perf_ctx_lock(cpuctx, task_ctx);
320 if (task == TASK_TOMBSTONE)
325 * We must be either inactive or active and the right task,
326 * otherwise we're screwed, since we cannot IPI to somewhere
329 if (ctx->is_active) {
330 if (WARN_ON_ONCE(task != current))
333 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
337 WARN_ON_ONCE(&cpuctx->ctx != ctx);
340 func(event, cpuctx, ctx, data);
342 perf_ctx_unlock(cpuctx, task_ctx);
345 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
346 PERF_FLAG_FD_OUTPUT |\
347 PERF_FLAG_PID_CGROUP |\
348 PERF_FLAG_FD_CLOEXEC)
351 * branch priv levels that need permission checks
353 #define PERF_SAMPLE_BRANCH_PERM_PLM \
354 (PERF_SAMPLE_BRANCH_KERNEL |\
355 PERF_SAMPLE_BRANCH_HV)
358 EVENT_FLEXIBLE = 0x1,
361 /* see ctx_resched() for details */
363 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
367 * perf_sched_events : >0 events exist
368 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
371 static void perf_sched_delayed(struct work_struct *work);
372 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
373 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
374 static DEFINE_MUTEX(perf_sched_mutex);
375 static atomic_t perf_sched_count;
377 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
378 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
379 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
381 static atomic_t nr_mmap_events __read_mostly;
382 static atomic_t nr_comm_events __read_mostly;
383 static atomic_t nr_namespaces_events __read_mostly;
384 static atomic_t nr_task_events __read_mostly;
385 static atomic_t nr_freq_events __read_mostly;
386 static atomic_t nr_switch_events __read_mostly;
387 static atomic_t nr_ksymbol_events __read_mostly;
388 static atomic_t nr_bpf_events __read_mostly;
390 static LIST_HEAD(pmus);
391 static DEFINE_MUTEX(pmus_lock);
392 static struct srcu_struct pmus_srcu;
393 static cpumask_var_t perf_online_mask;
396 * perf event paranoia level:
397 * -1 - not paranoid at all
398 * 0 - disallow raw tracepoint access for unpriv
399 * 1 - disallow cpu events for unpriv
400 * 2 - disallow kernel profiling for unpriv
402 int sysctl_perf_event_paranoid __read_mostly = 2;
404 /* Minimum for 512 kiB + 1 user control page */
405 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
408 * max perf event sample rate
410 #define DEFAULT_MAX_SAMPLE_RATE 100000
411 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
412 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
414 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
416 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
417 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
419 static int perf_sample_allowed_ns __read_mostly =
420 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
422 static void update_perf_cpu_limits(void)
424 u64 tmp = perf_sample_period_ns;
426 tmp *= sysctl_perf_cpu_time_max_percent;
427 tmp = div_u64(tmp, 100);
431 WRITE_ONCE(perf_sample_allowed_ns, tmp);
434 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
436 int perf_proc_update_handler(struct ctl_table *table, int write,
437 void __user *buffer, size_t *lenp,
441 int perf_cpu = sysctl_perf_cpu_time_max_percent;
443 * If throttling is disabled don't allow the write:
445 if (write && (perf_cpu == 100 || perf_cpu == 0))
448 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
452 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
453 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
454 update_perf_cpu_limits();
459 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
461 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
462 void __user *buffer, size_t *lenp,
465 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
470 if (sysctl_perf_cpu_time_max_percent == 100 ||
471 sysctl_perf_cpu_time_max_percent == 0) {
473 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
474 WRITE_ONCE(perf_sample_allowed_ns, 0);
476 update_perf_cpu_limits();
483 * perf samples are done in some very critical code paths (NMIs).
484 * If they take too much CPU time, the system can lock up and not
485 * get any real work done. This will drop the sample rate when
486 * we detect that events are taking too long.
488 #define NR_ACCUMULATED_SAMPLES 128
489 static DEFINE_PER_CPU(u64, running_sample_length);
491 static u64 __report_avg;
492 static u64 __report_allowed;
494 static void perf_duration_warn(struct irq_work *w)
496 printk_ratelimited(KERN_INFO
497 "perf: interrupt took too long (%lld > %lld), lowering "
498 "kernel.perf_event_max_sample_rate to %d\n",
499 __report_avg, __report_allowed,
500 sysctl_perf_event_sample_rate);
503 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
505 void perf_sample_event_took(u64 sample_len_ns)
507 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
515 /* Decay the counter by 1 average sample. */
516 running_len = __this_cpu_read(running_sample_length);
517 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
518 running_len += sample_len_ns;
519 __this_cpu_write(running_sample_length, running_len);
522 * Note: this will be biased artifically low until we have
523 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
524 * from having to maintain a count.
526 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
527 if (avg_len <= max_len)
530 __report_avg = avg_len;
531 __report_allowed = max_len;
534 * Compute a throttle threshold 25% below the current duration.
536 avg_len += avg_len / 4;
537 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
543 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
544 WRITE_ONCE(max_samples_per_tick, max);
546 sysctl_perf_event_sample_rate = max * HZ;
547 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
549 if (!irq_work_queue(&perf_duration_work)) {
550 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
551 "kernel.perf_event_max_sample_rate to %d\n",
552 __report_avg, __report_allowed,
553 sysctl_perf_event_sample_rate);
557 static atomic64_t perf_event_id;
559 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
560 enum event_type_t event_type);
562 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
563 enum event_type_t event_type,
564 struct task_struct *task);
566 static void update_context_time(struct perf_event_context *ctx);
567 static u64 perf_event_time(struct perf_event *event);
569 void __weak perf_event_print_debug(void) { }
571 extern __weak const char *perf_pmu_name(void)
576 static inline u64 perf_clock(void)
578 return local_clock();
581 static inline u64 perf_event_clock(struct perf_event *event)
583 return event->clock();
587 * State based event timekeeping...
589 * The basic idea is to use event->state to determine which (if any) time
590 * fields to increment with the current delta. This means we only need to
591 * update timestamps when we change state or when they are explicitly requested
594 * Event groups make things a little more complicated, but not terribly so. The
595 * rules for a group are that if the group leader is OFF the entire group is
596 * OFF, irrespecive of what the group member states are. This results in
597 * __perf_effective_state().
599 * A futher ramification is that when a group leader flips between OFF and
600 * !OFF, we need to update all group member times.
603 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
604 * need to make sure the relevant context time is updated before we try and
605 * update our timestamps.
608 static __always_inline enum perf_event_state
609 __perf_effective_state(struct perf_event *event)
611 struct perf_event *leader = event->group_leader;
613 if (leader->state <= PERF_EVENT_STATE_OFF)
614 return leader->state;
619 static __always_inline void
620 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
622 enum perf_event_state state = __perf_effective_state(event);
623 u64 delta = now - event->tstamp;
625 *enabled = event->total_time_enabled;
626 if (state >= PERF_EVENT_STATE_INACTIVE)
629 *running = event->total_time_running;
630 if (state >= PERF_EVENT_STATE_ACTIVE)
634 static void perf_event_update_time(struct perf_event *event)
636 u64 now = perf_event_time(event);
638 __perf_update_times(event, now, &event->total_time_enabled,
639 &event->total_time_running);
643 static void perf_event_update_sibling_time(struct perf_event *leader)
645 struct perf_event *sibling;
647 for_each_sibling_event(sibling, leader)
648 perf_event_update_time(sibling);
652 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
654 if (event->state == state)
657 perf_event_update_time(event);
659 * If a group leader gets enabled/disabled all its siblings
662 if ((event->state < 0) ^ (state < 0))
663 perf_event_update_sibling_time(event);
665 WRITE_ONCE(event->state, state);
668 #ifdef CONFIG_CGROUP_PERF
671 perf_cgroup_match(struct perf_event *event)
673 struct perf_event_context *ctx = event->ctx;
674 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
676 /* @event doesn't care about cgroup */
680 /* wants specific cgroup scope but @cpuctx isn't associated with any */
685 * Cgroup scoping is recursive. An event enabled for a cgroup is
686 * also enabled for all its descendant cgroups. If @cpuctx's
687 * cgroup is a descendant of @event's (the test covers identity
688 * case), it's a match.
690 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
691 event->cgrp->css.cgroup);
694 static inline void perf_detach_cgroup(struct perf_event *event)
696 css_put(&event->cgrp->css);
700 static inline int is_cgroup_event(struct perf_event *event)
702 return event->cgrp != NULL;
705 static inline u64 perf_cgroup_event_time(struct perf_event *event)
707 struct perf_cgroup_info *t;
709 t = per_cpu_ptr(event->cgrp->info, event->cpu);
713 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
715 struct perf_cgroup_info *info;
720 info = this_cpu_ptr(cgrp->info);
722 info->time += now - info->timestamp;
723 info->timestamp = now;
726 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
728 struct perf_cgroup *cgrp = cpuctx->cgrp;
729 struct cgroup_subsys_state *css;
732 for (css = &cgrp->css; css; css = css->parent) {
733 cgrp = container_of(css, struct perf_cgroup, css);
734 __update_cgrp_time(cgrp);
739 static inline void update_cgrp_time_from_event(struct perf_event *event)
741 struct perf_cgroup *cgrp;
744 * ensure we access cgroup data only when needed and
745 * when we know the cgroup is pinned (css_get)
747 if (!is_cgroup_event(event))
750 cgrp = perf_cgroup_from_task(current, event->ctx);
752 * Do not update time when cgroup is not active
754 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
755 __update_cgrp_time(event->cgrp);
759 perf_cgroup_set_timestamp(struct task_struct *task,
760 struct perf_event_context *ctx)
762 struct perf_cgroup *cgrp;
763 struct perf_cgroup_info *info;
764 struct cgroup_subsys_state *css;
767 * ctx->lock held by caller
768 * ensure we do not access cgroup data
769 * unless we have the cgroup pinned (css_get)
771 if (!task || !ctx->nr_cgroups)
774 cgrp = perf_cgroup_from_task(task, ctx);
776 for (css = &cgrp->css; css; css = css->parent) {
777 cgrp = container_of(css, struct perf_cgroup, css);
778 info = this_cpu_ptr(cgrp->info);
779 info->timestamp = ctx->timestamp;
783 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
785 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
786 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
789 * reschedule events based on the cgroup constraint of task.
791 * mode SWOUT : schedule out everything
792 * mode SWIN : schedule in based on cgroup for next
794 static void perf_cgroup_switch(struct task_struct *task, int mode)
796 struct perf_cpu_context *cpuctx;
797 struct list_head *list;
801 * Disable interrupts and preemption to avoid this CPU's
802 * cgrp_cpuctx_entry to change under us.
804 local_irq_save(flags);
806 list = this_cpu_ptr(&cgrp_cpuctx_list);
807 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
808 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
810 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
811 perf_pmu_disable(cpuctx->ctx.pmu);
813 if (mode & PERF_CGROUP_SWOUT) {
814 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
816 * must not be done before ctxswout due
817 * to event_filter_match() in event_sched_out()
822 if (mode & PERF_CGROUP_SWIN) {
823 WARN_ON_ONCE(cpuctx->cgrp);
825 * set cgrp before ctxsw in to allow
826 * event_filter_match() to not have to pass
828 * we pass the cpuctx->ctx to perf_cgroup_from_task()
829 * because cgorup events are only per-cpu
831 cpuctx->cgrp = perf_cgroup_from_task(task,
833 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
835 perf_pmu_enable(cpuctx->ctx.pmu);
836 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
839 local_irq_restore(flags);
842 static inline void perf_cgroup_sched_out(struct task_struct *task,
843 struct task_struct *next)
845 struct perf_cgroup *cgrp1;
846 struct perf_cgroup *cgrp2 = NULL;
850 * we come here when we know perf_cgroup_events > 0
851 * we do not need to pass the ctx here because we know
852 * we are holding the rcu lock
854 cgrp1 = perf_cgroup_from_task(task, NULL);
855 cgrp2 = perf_cgroup_from_task(next, NULL);
858 * only schedule out current cgroup events if we know
859 * that we are switching to a different cgroup. Otherwise,
860 * do no touch the cgroup events.
863 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
868 static inline void perf_cgroup_sched_in(struct task_struct *prev,
869 struct task_struct *task)
871 struct perf_cgroup *cgrp1;
872 struct perf_cgroup *cgrp2 = NULL;
876 * we come here when we know perf_cgroup_events > 0
877 * we do not need to pass the ctx here because we know
878 * we are holding the rcu lock
880 cgrp1 = perf_cgroup_from_task(task, NULL);
881 cgrp2 = perf_cgroup_from_task(prev, NULL);
884 * only need to schedule in cgroup events if we are changing
885 * cgroup during ctxsw. Cgroup events were not scheduled
886 * out of ctxsw out if that was not the case.
889 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
894 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
895 struct perf_event_attr *attr,
896 struct perf_event *group_leader)
898 struct perf_cgroup *cgrp;
899 struct cgroup_subsys_state *css;
900 struct fd f = fdget(fd);
906 css = css_tryget_online_from_dir(f.file->f_path.dentry,
907 &perf_event_cgrp_subsys);
913 cgrp = container_of(css, struct perf_cgroup, css);
917 * all events in a group must monitor
918 * the same cgroup because a task belongs
919 * to only one perf cgroup at a time
921 if (group_leader && group_leader->cgrp != cgrp) {
922 perf_detach_cgroup(event);
931 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
933 struct perf_cgroup_info *t;
934 t = per_cpu_ptr(event->cgrp->info, event->cpu);
935 event->shadow_ctx_time = now - t->timestamp;
939 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
940 * cleared when last cgroup event is removed.
943 list_update_cgroup_event(struct perf_event *event,
944 struct perf_event_context *ctx, bool add)
946 struct perf_cpu_context *cpuctx;
947 struct list_head *cpuctx_entry;
949 if (!is_cgroup_event(event))
953 * Because cgroup events are always per-cpu events,
954 * this will always be called from the right CPU.
956 cpuctx = __get_cpu_context(ctx);
959 * Since setting cpuctx->cgrp is conditional on the current @cgrp
960 * matching the event's cgroup, we must do this for every new event,
961 * because if the first would mismatch, the second would not try again
962 * and we would leave cpuctx->cgrp unset.
964 if (add && !cpuctx->cgrp) {
965 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
967 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
971 if (add && ctx->nr_cgroups++)
973 else if (!add && --ctx->nr_cgroups)
976 /* no cgroup running */
980 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
982 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
984 list_del(cpuctx_entry);
987 #else /* !CONFIG_CGROUP_PERF */
990 perf_cgroup_match(struct perf_event *event)
995 static inline void perf_detach_cgroup(struct perf_event *event)
998 static inline int is_cgroup_event(struct perf_event *event)
1003 static inline void update_cgrp_time_from_event(struct perf_event *event)
1007 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1011 static inline void perf_cgroup_sched_out(struct task_struct *task,
1012 struct task_struct *next)
1016 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1017 struct task_struct *task)
1021 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1022 struct perf_event_attr *attr,
1023 struct perf_event *group_leader)
1029 perf_cgroup_set_timestamp(struct task_struct *task,
1030 struct perf_event_context *ctx)
1035 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1040 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1044 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1050 list_update_cgroup_event(struct perf_event *event,
1051 struct perf_event_context *ctx, bool add)
1058 * set default to be dependent on timer tick just
1059 * like original code
1061 #define PERF_CPU_HRTIMER (1000 / HZ)
1063 * function must be called with interrupts disabled
1065 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1067 struct perf_cpu_context *cpuctx;
1070 lockdep_assert_irqs_disabled();
1072 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1073 rotations = perf_rotate_context(cpuctx);
1075 raw_spin_lock(&cpuctx->hrtimer_lock);
1077 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1079 cpuctx->hrtimer_active = 0;
1080 raw_spin_unlock(&cpuctx->hrtimer_lock);
1082 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1085 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1087 struct hrtimer *timer = &cpuctx->hrtimer;
1088 struct pmu *pmu = cpuctx->ctx.pmu;
1091 /* no multiplexing needed for SW PMU */
1092 if (pmu->task_ctx_nr == perf_sw_context)
1096 * check default is sane, if not set then force to
1097 * default interval (1/tick)
1099 interval = pmu->hrtimer_interval_ms;
1101 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1103 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1105 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1106 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1107 timer->function = perf_mux_hrtimer_handler;
1110 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1112 struct hrtimer *timer = &cpuctx->hrtimer;
1113 struct pmu *pmu = cpuctx->ctx.pmu;
1114 unsigned long flags;
1116 /* not for SW PMU */
1117 if (pmu->task_ctx_nr == perf_sw_context)
1120 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1121 if (!cpuctx->hrtimer_active) {
1122 cpuctx->hrtimer_active = 1;
1123 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1124 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1126 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1131 void perf_pmu_disable(struct pmu *pmu)
1133 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1135 pmu->pmu_disable(pmu);
1138 void perf_pmu_enable(struct pmu *pmu)
1140 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1142 pmu->pmu_enable(pmu);
1145 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1148 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1149 * perf_event_task_tick() are fully serialized because they're strictly cpu
1150 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1151 * disabled, while perf_event_task_tick is called from IRQ context.
1153 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1155 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1157 lockdep_assert_irqs_disabled();
1159 WARN_ON(!list_empty(&ctx->active_ctx_list));
1161 list_add(&ctx->active_ctx_list, head);
1164 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1166 lockdep_assert_irqs_disabled();
1168 WARN_ON(list_empty(&ctx->active_ctx_list));
1170 list_del_init(&ctx->active_ctx_list);
1173 static void get_ctx(struct perf_event_context *ctx)
1175 refcount_inc(&ctx->refcount);
1178 static void free_ctx(struct rcu_head *head)
1180 struct perf_event_context *ctx;
1182 ctx = container_of(head, struct perf_event_context, rcu_head);
1183 kfree(ctx->task_ctx_data);
1187 static void put_ctx(struct perf_event_context *ctx)
1189 if (refcount_dec_and_test(&ctx->refcount)) {
1190 if (ctx->parent_ctx)
1191 put_ctx(ctx->parent_ctx);
1192 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1193 put_task_struct(ctx->task);
1194 call_rcu(&ctx->rcu_head, free_ctx);
1199 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1200 * perf_pmu_migrate_context() we need some magic.
1202 * Those places that change perf_event::ctx will hold both
1203 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1205 * Lock ordering is by mutex address. There are two other sites where
1206 * perf_event_context::mutex nests and those are:
1208 * - perf_event_exit_task_context() [ child , 0 ]
1209 * perf_event_exit_event()
1210 * put_event() [ parent, 1 ]
1212 * - perf_event_init_context() [ parent, 0 ]
1213 * inherit_task_group()
1216 * perf_event_alloc()
1218 * perf_try_init_event() [ child , 1 ]
1220 * While it appears there is an obvious deadlock here -- the parent and child
1221 * nesting levels are inverted between the two. This is in fact safe because
1222 * life-time rules separate them. That is an exiting task cannot fork, and a
1223 * spawning task cannot (yet) exit.
1225 * But remember that that these are parent<->child context relations, and
1226 * migration does not affect children, therefore these two orderings should not
1229 * The change in perf_event::ctx does not affect children (as claimed above)
1230 * because the sys_perf_event_open() case will install a new event and break
1231 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1232 * concerned with cpuctx and that doesn't have children.
1234 * The places that change perf_event::ctx will issue:
1236 * perf_remove_from_context();
1237 * synchronize_rcu();
1238 * perf_install_in_context();
1240 * to affect the change. The remove_from_context() + synchronize_rcu() should
1241 * quiesce the event, after which we can install it in the new location. This
1242 * means that only external vectors (perf_fops, prctl) can perturb the event
1243 * while in transit. Therefore all such accessors should also acquire
1244 * perf_event_context::mutex to serialize against this.
1246 * However; because event->ctx can change while we're waiting to acquire
1247 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1252 * task_struct::perf_event_mutex
1253 * perf_event_context::mutex
1254 * perf_event::child_mutex;
1255 * perf_event_context::lock
1256 * perf_event::mmap_mutex
1258 * perf_addr_filters_head::lock
1262 * cpuctx->mutex / perf_event_context::mutex
1264 static struct perf_event_context *
1265 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1267 struct perf_event_context *ctx;
1271 ctx = READ_ONCE(event->ctx);
1272 if (!refcount_inc_not_zero(&ctx->refcount)) {
1278 mutex_lock_nested(&ctx->mutex, nesting);
1279 if (event->ctx != ctx) {
1280 mutex_unlock(&ctx->mutex);
1288 static inline struct perf_event_context *
1289 perf_event_ctx_lock(struct perf_event *event)
1291 return perf_event_ctx_lock_nested(event, 0);
1294 static void perf_event_ctx_unlock(struct perf_event *event,
1295 struct perf_event_context *ctx)
1297 mutex_unlock(&ctx->mutex);
1302 * This must be done under the ctx->lock, such as to serialize against
1303 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1304 * calling scheduler related locks and ctx->lock nests inside those.
1306 static __must_check struct perf_event_context *
1307 unclone_ctx(struct perf_event_context *ctx)
1309 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1311 lockdep_assert_held(&ctx->lock);
1314 ctx->parent_ctx = NULL;
1320 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1325 * only top level events have the pid namespace they were created in
1328 event = event->parent;
1330 nr = __task_pid_nr_ns(p, type, event->ns);
1331 /* avoid -1 if it is idle thread or runs in another ns */
1332 if (!nr && !pid_alive(p))
1337 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1339 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1342 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1344 return perf_event_pid_type(event, p, PIDTYPE_PID);
1348 * If we inherit events we want to return the parent event id
1351 static u64 primary_event_id(struct perf_event *event)
1356 id = event->parent->id;
1362 * Get the perf_event_context for a task and lock it.
1364 * This has to cope with with the fact that until it is locked,
1365 * the context could get moved to another task.
1367 static struct perf_event_context *
1368 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1370 struct perf_event_context *ctx;
1374 * One of the few rules of preemptible RCU is that one cannot do
1375 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1376 * part of the read side critical section was irqs-enabled -- see
1377 * rcu_read_unlock_special().
1379 * Since ctx->lock nests under rq->lock we must ensure the entire read
1380 * side critical section has interrupts disabled.
1382 local_irq_save(*flags);
1384 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1387 * If this context is a clone of another, it might
1388 * get swapped for another underneath us by
1389 * perf_event_task_sched_out, though the
1390 * rcu_read_lock() protects us from any context
1391 * getting freed. Lock the context and check if it
1392 * got swapped before we could get the lock, and retry
1393 * if so. If we locked the right context, then it
1394 * can't get swapped on us any more.
1396 raw_spin_lock(&ctx->lock);
1397 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1398 raw_spin_unlock(&ctx->lock);
1400 local_irq_restore(*flags);
1404 if (ctx->task == TASK_TOMBSTONE ||
1405 !refcount_inc_not_zero(&ctx->refcount)) {
1406 raw_spin_unlock(&ctx->lock);
1409 WARN_ON_ONCE(ctx->task != task);
1414 local_irq_restore(*flags);
1419 * Get the context for a task and increment its pin_count so it
1420 * can't get swapped to another task. This also increments its
1421 * reference count so that the context can't get freed.
1423 static struct perf_event_context *
1424 perf_pin_task_context(struct task_struct *task, int ctxn)
1426 struct perf_event_context *ctx;
1427 unsigned long flags;
1429 ctx = perf_lock_task_context(task, ctxn, &flags);
1432 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1437 static void perf_unpin_context(struct perf_event_context *ctx)
1439 unsigned long flags;
1441 raw_spin_lock_irqsave(&ctx->lock, flags);
1443 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1447 * Update the record of the current time in a context.
1449 static void update_context_time(struct perf_event_context *ctx)
1451 u64 now = perf_clock();
1453 ctx->time += now - ctx->timestamp;
1454 ctx->timestamp = now;
1457 static u64 perf_event_time(struct perf_event *event)
1459 struct perf_event_context *ctx = event->ctx;
1461 if (is_cgroup_event(event))
1462 return perf_cgroup_event_time(event);
1464 return ctx ? ctx->time : 0;
1467 static enum event_type_t get_event_type(struct perf_event *event)
1469 struct perf_event_context *ctx = event->ctx;
1470 enum event_type_t event_type;
1472 lockdep_assert_held(&ctx->lock);
1475 * It's 'group type', really, because if our group leader is
1476 * pinned, so are we.
1478 if (event->group_leader != event)
1479 event = event->group_leader;
1481 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1483 event_type |= EVENT_CPU;
1489 * Helper function to initialize event group nodes.
1491 static void init_event_group(struct perf_event *event)
1493 RB_CLEAR_NODE(&event->group_node);
1494 event->group_index = 0;
1498 * Extract pinned or flexible groups from the context
1499 * based on event attrs bits.
1501 static struct perf_event_groups *
1502 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1504 if (event->attr.pinned)
1505 return &ctx->pinned_groups;
1507 return &ctx->flexible_groups;
1511 * Helper function to initializes perf_event_group trees.
1513 static void perf_event_groups_init(struct perf_event_groups *groups)
1515 groups->tree = RB_ROOT;
1520 * Compare function for event groups;
1522 * Implements complex key that first sorts by CPU and then by virtual index
1523 * which provides ordering when rotating groups for the same CPU.
1526 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1528 if (left->cpu < right->cpu)
1530 if (left->cpu > right->cpu)
1533 if (left->group_index < right->group_index)
1535 if (left->group_index > right->group_index)
1542 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1543 * key (see perf_event_groups_less). This places it last inside the CPU
1547 perf_event_groups_insert(struct perf_event_groups *groups,
1548 struct perf_event *event)
1550 struct perf_event *node_event;
1551 struct rb_node *parent;
1552 struct rb_node **node;
1554 event->group_index = ++groups->index;
1556 node = &groups->tree.rb_node;
1561 node_event = container_of(*node, struct perf_event, group_node);
1563 if (perf_event_groups_less(event, node_event))
1564 node = &parent->rb_left;
1566 node = &parent->rb_right;
1569 rb_link_node(&event->group_node, parent, node);
1570 rb_insert_color(&event->group_node, &groups->tree);
1574 * Helper function to insert event into the pinned or flexible groups.
1577 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1579 struct perf_event_groups *groups;
1581 groups = get_event_groups(event, ctx);
1582 perf_event_groups_insert(groups, event);
1586 * Delete a group from a tree.
1589 perf_event_groups_delete(struct perf_event_groups *groups,
1590 struct perf_event *event)
1592 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1593 RB_EMPTY_ROOT(&groups->tree));
1595 rb_erase(&event->group_node, &groups->tree);
1596 init_event_group(event);
1600 * Helper function to delete event from its groups.
1603 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1605 struct perf_event_groups *groups;
1607 groups = get_event_groups(event, ctx);
1608 perf_event_groups_delete(groups, event);
1612 * Get the leftmost event in the @cpu subtree.
1614 static struct perf_event *
1615 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1617 struct perf_event *node_event = NULL, *match = NULL;
1618 struct rb_node *node = groups->tree.rb_node;
1621 node_event = container_of(node, struct perf_event, group_node);
1623 if (cpu < node_event->cpu) {
1624 node = node->rb_left;
1625 } else if (cpu > node_event->cpu) {
1626 node = node->rb_right;
1629 node = node->rb_left;
1637 * Like rb_entry_next_safe() for the @cpu subtree.
1639 static struct perf_event *
1640 perf_event_groups_next(struct perf_event *event)
1642 struct perf_event *next;
1644 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1645 if (next && next->cpu == event->cpu)
1652 * Iterate through the whole groups tree.
1654 #define perf_event_groups_for_each(event, groups) \
1655 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1656 typeof(*event), group_node); event; \
1657 event = rb_entry_safe(rb_next(&event->group_node), \
1658 typeof(*event), group_node))
1661 * Add an event from the lists for its context.
1662 * Must be called with ctx->mutex and ctx->lock held.
1665 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1667 lockdep_assert_held(&ctx->lock);
1669 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1670 event->attach_state |= PERF_ATTACH_CONTEXT;
1672 event->tstamp = perf_event_time(event);
1675 * If we're a stand alone event or group leader, we go to the context
1676 * list, group events are kept attached to the group so that
1677 * perf_group_detach can, at all times, locate all siblings.
1679 if (event->group_leader == event) {
1680 event->group_caps = event->event_caps;
1681 add_event_to_groups(event, ctx);
1684 list_update_cgroup_event(event, ctx, true);
1686 list_add_rcu(&event->event_entry, &ctx->event_list);
1688 if (event->attr.inherit_stat)
1695 * Initialize event state based on the perf_event_attr::disabled.
1697 static inline void perf_event__state_init(struct perf_event *event)
1699 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1700 PERF_EVENT_STATE_INACTIVE;
1703 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1705 int entry = sizeof(u64); /* value */
1709 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1710 size += sizeof(u64);
1712 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1713 size += sizeof(u64);
1715 if (event->attr.read_format & PERF_FORMAT_ID)
1716 entry += sizeof(u64);
1718 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1720 size += sizeof(u64);
1724 event->read_size = size;
1727 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1729 struct perf_sample_data *data;
1732 if (sample_type & PERF_SAMPLE_IP)
1733 size += sizeof(data->ip);
1735 if (sample_type & PERF_SAMPLE_ADDR)
1736 size += sizeof(data->addr);
1738 if (sample_type & PERF_SAMPLE_PERIOD)
1739 size += sizeof(data->period);
1741 if (sample_type & PERF_SAMPLE_WEIGHT)
1742 size += sizeof(data->weight);
1744 if (sample_type & PERF_SAMPLE_READ)
1745 size += event->read_size;
1747 if (sample_type & PERF_SAMPLE_DATA_SRC)
1748 size += sizeof(data->data_src.val);
1750 if (sample_type & PERF_SAMPLE_TRANSACTION)
1751 size += sizeof(data->txn);
1753 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1754 size += sizeof(data->phys_addr);
1756 event->header_size = size;
1760 * Called at perf_event creation and when events are attached/detached from a
1763 static void perf_event__header_size(struct perf_event *event)
1765 __perf_event_read_size(event,
1766 event->group_leader->nr_siblings);
1767 __perf_event_header_size(event, event->attr.sample_type);
1770 static void perf_event__id_header_size(struct perf_event *event)
1772 struct perf_sample_data *data;
1773 u64 sample_type = event->attr.sample_type;
1776 if (sample_type & PERF_SAMPLE_TID)
1777 size += sizeof(data->tid_entry);
1779 if (sample_type & PERF_SAMPLE_TIME)
1780 size += sizeof(data->time);
1782 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1783 size += sizeof(data->id);
1785 if (sample_type & PERF_SAMPLE_ID)
1786 size += sizeof(data->id);
1788 if (sample_type & PERF_SAMPLE_STREAM_ID)
1789 size += sizeof(data->stream_id);
1791 if (sample_type & PERF_SAMPLE_CPU)
1792 size += sizeof(data->cpu_entry);
1794 event->id_header_size = size;
1797 static bool perf_event_validate_size(struct perf_event *event)
1800 * The values computed here will be over-written when we actually
1803 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1804 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1805 perf_event__id_header_size(event);
1808 * Sum the lot; should not exceed the 64k limit we have on records.
1809 * Conservative limit to allow for callchains and other variable fields.
1811 if (event->read_size + event->header_size +
1812 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1818 static void perf_group_attach(struct perf_event *event)
1820 struct perf_event *group_leader = event->group_leader, *pos;
1822 lockdep_assert_held(&event->ctx->lock);
1825 * We can have double attach due to group movement in perf_event_open.
1827 if (event->attach_state & PERF_ATTACH_GROUP)
1830 event->attach_state |= PERF_ATTACH_GROUP;
1832 if (group_leader == event)
1835 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1837 group_leader->group_caps &= event->event_caps;
1839 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1840 group_leader->nr_siblings++;
1842 perf_event__header_size(group_leader);
1844 for_each_sibling_event(pos, group_leader)
1845 perf_event__header_size(pos);
1849 * Remove an event from the lists for its context.
1850 * Must be called with ctx->mutex and ctx->lock held.
1853 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1855 WARN_ON_ONCE(event->ctx != ctx);
1856 lockdep_assert_held(&ctx->lock);
1859 * We can have double detach due to exit/hot-unplug + close.
1861 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1864 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1866 list_update_cgroup_event(event, ctx, false);
1869 if (event->attr.inherit_stat)
1872 list_del_rcu(&event->event_entry);
1874 if (event->group_leader == event)
1875 del_event_from_groups(event, ctx);
1878 * If event was in error state, then keep it
1879 * that way, otherwise bogus counts will be
1880 * returned on read(). The only way to get out
1881 * of error state is by explicit re-enabling
1884 if (event->state > PERF_EVENT_STATE_OFF)
1885 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1891 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
1893 if (!has_aux(aux_event))
1896 if (!event->pmu->aux_output_match)
1899 return event->pmu->aux_output_match(aux_event);
1902 static void put_event(struct perf_event *event);
1903 static void event_sched_out(struct perf_event *event,
1904 struct perf_cpu_context *cpuctx,
1905 struct perf_event_context *ctx);
1907 static void perf_put_aux_event(struct perf_event *event)
1909 struct perf_event_context *ctx = event->ctx;
1910 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1911 struct perf_event *iter;
1914 * If event uses aux_event tear down the link
1916 if (event->aux_event) {
1917 iter = event->aux_event;
1918 event->aux_event = NULL;
1924 * If the event is an aux_event, tear down all links to
1925 * it from other events.
1927 for_each_sibling_event(iter, event->group_leader) {
1928 if (iter->aux_event != event)
1931 iter->aux_event = NULL;
1935 * If it's ACTIVE, schedule it out and put it into ERROR
1936 * state so that we don't try to schedule it again. Note
1937 * that perf_event_enable() will clear the ERROR status.
1939 event_sched_out(iter, cpuctx, ctx);
1940 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
1944 static int perf_get_aux_event(struct perf_event *event,
1945 struct perf_event *group_leader)
1948 * Our group leader must be an aux event if we want to be
1949 * an aux_output. This way, the aux event will precede its
1950 * aux_output events in the group, and therefore will always
1956 if (!perf_aux_output_match(event, group_leader))
1959 if (!atomic_long_inc_not_zero(&group_leader->refcount))
1963 * Link aux_outputs to their aux event; this is undone in
1964 * perf_group_detach() by perf_put_aux_event(). When the
1965 * group in torn down, the aux_output events loose their
1966 * link to the aux_event and can't schedule any more.
1968 event->aux_event = group_leader;
1973 static void perf_group_detach(struct perf_event *event)
1975 struct perf_event *sibling, *tmp;
1976 struct perf_event_context *ctx = event->ctx;
1978 lockdep_assert_held(&ctx->lock);
1981 * We can have double detach due to exit/hot-unplug + close.
1983 if (!(event->attach_state & PERF_ATTACH_GROUP))
1986 event->attach_state &= ~PERF_ATTACH_GROUP;
1988 perf_put_aux_event(event);
1991 * If this is a sibling, remove it from its group.
1993 if (event->group_leader != event) {
1994 list_del_init(&event->sibling_list);
1995 event->group_leader->nr_siblings--;
2000 * If this was a group event with sibling events then
2001 * upgrade the siblings to singleton events by adding them
2002 * to whatever list we are on.
2004 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2006 sibling->group_leader = sibling;
2007 list_del_init(&sibling->sibling_list);
2009 /* Inherit group flags from the previous leader */
2010 sibling->group_caps = event->group_caps;
2012 if (!RB_EMPTY_NODE(&event->group_node)) {
2013 add_event_to_groups(sibling, event->ctx);
2015 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
2016 struct list_head *list = sibling->attr.pinned ?
2017 &ctx->pinned_active : &ctx->flexible_active;
2019 list_add_tail(&sibling->active_list, list);
2023 WARN_ON_ONCE(sibling->ctx != event->ctx);
2027 perf_event__header_size(event->group_leader);
2029 for_each_sibling_event(tmp, event->group_leader)
2030 perf_event__header_size(tmp);
2033 static bool is_orphaned_event(struct perf_event *event)
2035 return event->state == PERF_EVENT_STATE_DEAD;
2038 static inline int __pmu_filter_match(struct perf_event *event)
2040 struct pmu *pmu = event->pmu;
2041 return pmu->filter_match ? pmu->filter_match(event) : 1;
2045 * Check whether we should attempt to schedule an event group based on
2046 * PMU-specific filtering. An event group can consist of HW and SW events,
2047 * potentially with a SW leader, so we must check all the filters, to
2048 * determine whether a group is schedulable:
2050 static inline int pmu_filter_match(struct perf_event *event)
2052 struct perf_event *sibling;
2054 if (!__pmu_filter_match(event))
2057 for_each_sibling_event(sibling, event) {
2058 if (!__pmu_filter_match(sibling))
2066 event_filter_match(struct perf_event *event)
2068 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2069 perf_cgroup_match(event) && pmu_filter_match(event);
2073 event_sched_out(struct perf_event *event,
2074 struct perf_cpu_context *cpuctx,
2075 struct perf_event_context *ctx)
2077 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2079 WARN_ON_ONCE(event->ctx != ctx);
2080 lockdep_assert_held(&ctx->lock);
2082 if (event->state != PERF_EVENT_STATE_ACTIVE)
2086 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2087 * we can schedule events _OUT_ individually through things like
2088 * __perf_remove_from_context().
2090 list_del_init(&event->active_list);
2092 perf_pmu_disable(event->pmu);
2094 event->pmu->del(event, 0);
2097 if (READ_ONCE(event->pending_disable) >= 0) {
2098 WRITE_ONCE(event->pending_disable, -1);
2099 state = PERF_EVENT_STATE_OFF;
2101 perf_event_set_state(event, state);
2103 if (!is_software_event(event))
2104 cpuctx->active_oncpu--;
2105 if (!--ctx->nr_active)
2106 perf_event_ctx_deactivate(ctx);
2107 if (event->attr.freq && event->attr.sample_freq)
2109 if (event->attr.exclusive || !cpuctx->active_oncpu)
2110 cpuctx->exclusive = 0;
2112 perf_pmu_enable(event->pmu);
2116 group_sched_out(struct perf_event *group_event,
2117 struct perf_cpu_context *cpuctx,
2118 struct perf_event_context *ctx)
2120 struct perf_event *event;
2122 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2125 perf_pmu_disable(ctx->pmu);
2127 event_sched_out(group_event, cpuctx, ctx);
2130 * Schedule out siblings (if any):
2132 for_each_sibling_event(event, group_event)
2133 event_sched_out(event, cpuctx, ctx);
2135 perf_pmu_enable(ctx->pmu);
2137 if (group_event->attr.exclusive)
2138 cpuctx->exclusive = 0;
2141 #define DETACH_GROUP 0x01UL
2144 * Cross CPU call to remove a performance event
2146 * We disable the event on the hardware level first. After that we
2147 * remove it from the context list.
2150 __perf_remove_from_context(struct perf_event *event,
2151 struct perf_cpu_context *cpuctx,
2152 struct perf_event_context *ctx,
2155 unsigned long flags = (unsigned long)info;
2157 if (ctx->is_active & EVENT_TIME) {
2158 update_context_time(ctx);
2159 update_cgrp_time_from_cpuctx(cpuctx);
2162 event_sched_out(event, cpuctx, ctx);
2163 if (flags & DETACH_GROUP)
2164 perf_group_detach(event);
2165 list_del_event(event, ctx);
2167 if (!ctx->nr_events && ctx->is_active) {
2170 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2171 cpuctx->task_ctx = NULL;
2177 * Remove the event from a task's (or a CPU's) list of events.
2179 * If event->ctx is a cloned context, callers must make sure that
2180 * every task struct that event->ctx->task could possibly point to
2181 * remains valid. This is OK when called from perf_release since
2182 * that only calls us on the top-level context, which can't be a clone.
2183 * When called from perf_event_exit_task, it's OK because the
2184 * context has been detached from its task.
2186 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2188 struct perf_event_context *ctx = event->ctx;
2190 lockdep_assert_held(&ctx->mutex);
2192 event_function_call(event, __perf_remove_from_context, (void *)flags);
2195 * The above event_function_call() can NO-OP when it hits
2196 * TASK_TOMBSTONE. In that case we must already have been detached
2197 * from the context (by perf_event_exit_event()) but the grouping
2198 * might still be in-tact.
2200 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2201 if ((flags & DETACH_GROUP) &&
2202 (event->attach_state & PERF_ATTACH_GROUP)) {
2204 * Since in that case we cannot possibly be scheduled, simply
2207 raw_spin_lock_irq(&ctx->lock);
2208 perf_group_detach(event);
2209 raw_spin_unlock_irq(&ctx->lock);
2214 * Cross CPU call to disable a performance event
2216 static void __perf_event_disable(struct perf_event *event,
2217 struct perf_cpu_context *cpuctx,
2218 struct perf_event_context *ctx,
2221 if (event->state < PERF_EVENT_STATE_INACTIVE)
2224 if (ctx->is_active & EVENT_TIME) {
2225 update_context_time(ctx);
2226 update_cgrp_time_from_event(event);
2229 if (event == event->group_leader)
2230 group_sched_out(event, cpuctx, ctx);
2232 event_sched_out(event, cpuctx, ctx);
2234 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2240 * If event->ctx is a cloned context, callers must make sure that
2241 * every task struct that event->ctx->task could possibly point to
2242 * remains valid. This condition is satisfied when called through
2243 * perf_event_for_each_child or perf_event_for_each because they
2244 * hold the top-level event's child_mutex, so any descendant that
2245 * goes to exit will block in perf_event_exit_event().
2247 * When called from perf_pending_event it's OK because event->ctx
2248 * is the current context on this CPU and preemption is disabled,
2249 * hence we can't get into perf_event_task_sched_out for this context.
2251 static void _perf_event_disable(struct perf_event *event)
2253 struct perf_event_context *ctx = event->ctx;
2255 raw_spin_lock_irq(&ctx->lock);
2256 if (event->state <= PERF_EVENT_STATE_OFF) {
2257 raw_spin_unlock_irq(&ctx->lock);
2260 raw_spin_unlock_irq(&ctx->lock);
2262 event_function_call(event, __perf_event_disable, NULL);
2265 void perf_event_disable_local(struct perf_event *event)
2267 event_function_local(event, __perf_event_disable, NULL);
2271 * Strictly speaking kernel users cannot create groups and therefore this
2272 * interface does not need the perf_event_ctx_lock() magic.
2274 void perf_event_disable(struct perf_event *event)
2276 struct perf_event_context *ctx;
2278 ctx = perf_event_ctx_lock(event);
2279 _perf_event_disable(event);
2280 perf_event_ctx_unlock(event, ctx);
2282 EXPORT_SYMBOL_GPL(perf_event_disable);
2284 void perf_event_disable_inatomic(struct perf_event *event)
2286 WRITE_ONCE(event->pending_disable, smp_processor_id());
2287 /* can fail, see perf_pending_event_disable() */
2288 irq_work_queue(&event->pending);
2291 static void perf_set_shadow_time(struct perf_event *event,
2292 struct perf_event_context *ctx)
2295 * use the correct time source for the time snapshot
2297 * We could get by without this by leveraging the
2298 * fact that to get to this function, the caller
2299 * has most likely already called update_context_time()
2300 * and update_cgrp_time_xx() and thus both timestamp
2301 * are identical (or very close). Given that tstamp is,
2302 * already adjusted for cgroup, we could say that:
2303 * tstamp - ctx->timestamp
2305 * tstamp - cgrp->timestamp.
2307 * Then, in perf_output_read(), the calculation would
2308 * work with no changes because:
2309 * - event is guaranteed scheduled in
2310 * - no scheduled out in between
2311 * - thus the timestamp would be the same
2313 * But this is a bit hairy.
2315 * So instead, we have an explicit cgroup call to remain
2316 * within the time time source all along. We believe it
2317 * is cleaner and simpler to understand.
2319 if (is_cgroup_event(event))
2320 perf_cgroup_set_shadow_time(event, event->tstamp);
2322 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2325 #define MAX_INTERRUPTS (~0ULL)
2327 static void perf_log_throttle(struct perf_event *event, int enable);
2328 static void perf_log_itrace_start(struct perf_event *event);
2331 event_sched_in(struct perf_event *event,
2332 struct perf_cpu_context *cpuctx,
2333 struct perf_event_context *ctx)
2337 lockdep_assert_held(&ctx->lock);
2339 if (event->state <= PERF_EVENT_STATE_OFF)
2342 WRITE_ONCE(event->oncpu, smp_processor_id());
2344 * Order event::oncpu write to happen before the ACTIVE state is
2345 * visible. This allows perf_event_{stop,read}() to observe the correct
2346 * ->oncpu if it sees ACTIVE.
2349 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2352 * Unthrottle events, since we scheduled we might have missed several
2353 * ticks already, also for a heavily scheduling task there is little
2354 * guarantee it'll get a tick in a timely manner.
2356 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2357 perf_log_throttle(event, 1);
2358 event->hw.interrupts = 0;
2361 perf_pmu_disable(event->pmu);
2363 perf_set_shadow_time(event, ctx);
2365 perf_log_itrace_start(event);
2367 if (event->pmu->add(event, PERF_EF_START)) {
2368 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2374 if (!is_software_event(event))
2375 cpuctx->active_oncpu++;
2376 if (!ctx->nr_active++)
2377 perf_event_ctx_activate(ctx);
2378 if (event->attr.freq && event->attr.sample_freq)
2381 if (event->attr.exclusive)
2382 cpuctx->exclusive = 1;
2385 perf_pmu_enable(event->pmu);
2391 group_sched_in(struct perf_event *group_event,
2392 struct perf_cpu_context *cpuctx,
2393 struct perf_event_context *ctx)
2395 struct perf_event *event, *partial_group = NULL;
2396 struct pmu *pmu = ctx->pmu;
2398 if (group_event->state == PERF_EVENT_STATE_OFF)
2401 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2403 if (event_sched_in(group_event, cpuctx, ctx)) {
2404 pmu->cancel_txn(pmu);
2405 perf_mux_hrtimer_restart(cpuctx);
2410 * Schedule in siblings as one group (if any):
2412 for_each_sibling_event(event, group_event) {
2413 if (event_sched_in(event, cpuctx, ctx)) {
2414 partial_group = event;
2419 if (!pmu->commit_txn(pmu))
2424 * Groups can be scheduled in as one unit only, so undo any
2425 * partial group before returning:
2426 * The events up to the failed event are scheduled out normally.
2428 for_each_sibling_event(event, group_event) {
2429 if (event == partial_group)
2432 event_sched_out(event, cpuctx, ctx);
2434 event_sched_out(group_event, cpuctx, ctx);
2436 pmu->cancel_txn(pmu);
2438 perf_mux_hrtimer_restart(cpuctx);
2444 * Work out whether we can put this event group on the CPU now.
2446 static int group_can_go_on(struct perf_event *event,
2447 struct perf_cpu_context *cpuctx,
2451 * Groups consisting entirely of software events can always go on.
2453 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2456 * If an exclusive group is already on, no other hardware
2459 if (cpuctx->exclusive)
2462 * If this group is exclusive and there are already
2463 * events on the CPU, it can't go on.
2465 if (event->attr.exclusive && cpuctx->active_oncpu)
2468 * Otherwise, try to add it if all previous groups were able
2474 static void add_event_to_ctx(struct perf_event *event,
2475 struct perf_event_context *ctx)
2477 list_add_event(event, ctx);
2478 perf_group_attach(event);
2481 static void ctx_sched_out(struct perf_event_context *ctx,
2482 struct perf_cpu_context *cpuctx,
2483 enum event_type_t event_type);
2485 ctx_sched_in(struct perf_event_context *ctx,
2486 struct perf_cpu_context *cpuctx,
2487 enum event_type_t event_type,
2488 struct task_struct *task);
2490 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2491 struct perf_event_context *ctx,
2492 enum event_type_t event_type)
2494 if (!cpuctx->task_ctx)
2497 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2500 ctx_sched_out(ctx, cpuctx, event_type);
2503 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2504 struct perf_event_context *ctx,
2505 struct task_struct *task)
2507 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2509 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2510 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2512 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2516 * We want to maintain the following priority of scheduling:
2517 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2518 * - task pinned (EVENT_PINNED)
2519 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2520 * - task flexible (EVENT_FLEXIBLE).
2522 * In order to avoid unscheduling and scheduling back in everything every
2523 * time an event is added, only do it for the groups of equal priority and
2526 * This can be called after a batch operation on task events, in which case
2527 * event_type is a bit mask of the types of events involved. For CPU events,
2528 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2530 static void ctx_resched(struct perf_cpu_context *cpuctx,
2531 struct perf_event_context *task_ctx,
2532 enum event_type_t event_type)
2534 enum event_type_t ctx_event_type;
2535 bool cpu_event = !!(event_type & EVENT_CPU);
2538 * If pinned groups are involved, flexible groups also need to be
2541 if (event_type & EVENT_PINNED)
2542 event_type |= EVENT_FLEXIBLE;
2544 ctx_event_type = event_type & EVENT_ALL;
2546 perf_pmu_disable(cpuctx->ctx.pmu);
2548 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2551 * Decide which cpu ctx groups to schedule out based on the types
2552 * of events that caused rescheduling:
2553 * - EVENT_CPU: schedule out corresponding groups;
2554 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2555 * - otherwise, do nothing more.
2558 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2559 else if (ctx_event_type & EVENT_PINNED)
2560 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2562 perf_event_sched_in(cpuctx, task_ctx, current);
2563 perf_pmu_enable(cpuctx->ctx.pmu);
2566 void perf_pmu_resched(struct pmu *pmu)
2568 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2569 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2571 perf_ctx_lock(cpuctx, task_ctx);
2572 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2573 perf_ctx_unlock(cpuctx, task_ctx);
2577 * Cross CPU call to install and enable a performance event
2579 * Very similar to remote_function() + event_function() but cannot assume that
2580 * things like ctx->is_active and cpuctx->task_ctx are set.
2582 static int __perf_install_in_context(void *info)
2584 struct perf_event *event = info;
2585 struct perf_event_context *ctx = event->ctx;
2586 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2587 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2588 bool reprogram = true;
2591 raw_spin_lock(&cpuctx->ctx.lock);
2593 raw_spin_lock(&ctx->lock);
2596 reprogram = (ctx->task == current);
2599 * If the task is running, it must be running on this CPU,
2600 * otherwise we cannot reprogram things.
2602 * If its not running, we don't care, ctx->lock will
2603 * serialize against it becoming runnable.
2605 if (task_curr(ctx->task) && !reprogram) {
2610 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2611 } else if (task_ctx) {
2612 raw_spin_lock(&task_ctx->lock);
2615 #ifdef CONFIG_CGROUP_PERF
2616 if (is_cgroup_event(event)) {
2618 * If the current cgroup doesn't match the event's
2619 * cgroup, we should not try to schedule it.
2621 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2622 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2623 event->cgrp->css.cgroup);
2628 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2629 add_event_to_ctx(event, ctx);
2630 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2632 add_event_to_ctx(event, ctx);
2636 perf_ctx_unlock(cpuctx, task_ctx);
2641 static bool exclusive_event_installable(struct perf_event *event,
2642 struct perf_event_context *ctx);
2645 * Attach a performance event to a context.
2647 * Very similar to event_function_call, see comment there.
2650 perf_install_in_context(struct perf_event_context *ctx,
2651 struct perf_event *event,
2654 struct task_struct *task = READ_ONCE(ctx->task);
2656 lockdep_assert_held(&ctx->mutex);
2658 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2660 if (event->cpu != -1)
2664 * Ensures that if we can observe event->ctx, both the event and ctx
2665 * will be 'complete'. See perf_iterate_sb_cpu().
2667 smp_store_release(&event->ctx, ctx);
2670 cpu_function_call(cpu, __perf_install_in_context, event);
2675 * Should not happen, we validate the ctx is still alive before calling.
2677 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2681 * Installing events is tricky because we cannot rely on ctx->is_active
2682 * to be set in case this is the nr_events 0 -> 1 transition.
2684 * Instead we use task_curr(), which tells us if the task is running.
2685 * However, since we use task_curr() outside of rq::lock, we can race
2686 * against the actual state. This means the result can be wrong.
2688 * If we get a false positive, we retry, this is harmless.
2690 * If we get a false negative, things are complicated. If we are after
2691 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2692 * value must be correct. If we're before, it doesn't matter since
2693 * perf_event_context_sched_in() will program the counter.
2695 * However, this hinges on the remote context switch having observed
2696 * our task->perf_event_ctxp[] store, such that it will in fact take
2697 * ctx::lock in perf_event_context_sched_in().
2699 * We do this by task_function_call(), if the IPI fails to hit the task
2700 * we know any future context switch of task must see the
2701 * perf_event_ctpx[] store.
2705 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2706 * task_cpu() load, such that if the IPI then does not find the task
2707 * running, a future context switch of that task must observe the
2712 if (!task_function_call(task, __perf_install_in_context, event))
2715 raw_spin_lock_irq(&ctx->lock);
2717 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2719 * Cannot happen because we already checked above (which also
2720 * cannot happen), and we hold ctx->mutex, which serializes us
2721 * against perf_event_exit_task_context().
2723 raw_spin_unlock_irq(&ctx->lock);
2727 * If the task is not running, ctx->lock will avoid it becoming so,
2728 * thus we can safely install the event.
2730 if (task_curr(task)) {
2731 raw_spin_unlock_irq(&ctx->lock);
2734 add_event_to_ctx(event, ctx);
2735 raw_spin_unlock_irq(&ctx->lock);
2739 * Cross CPU call to enable a performance event
2741 static void __perf_event_enable(struct perf_event *event,
2742 struct perf_cpu_context *cpuctx,
2743 struct perf_event_context *ctx,
2746 struct perf_event *leader = event->group_leader;
2747 struct perf_event_context *task_ctx;
2749 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2750 event->state <= PERF_EVENT_STATE_ERROR)
2754 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2756 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2758 if (!ctx->is_active)
2761 if (!event_filter_match(event)) {
2762 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2767 * If the event is in a group and isn't the group leader,
2768 * then don't put it on unless the group is on.
2770 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2771 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2775 task_ctx = cpuctx->task_ctx;
2777 WARN_ON_ONCE(task_ctx != ctx);
2779 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2785 * If event->ctx is a cloned context, callers must make sure that
2786 * every task struct that event->ctx->task could possibly point to
2787 * remains valid. This condition is satisfied when called through
2788 * perf_event_for_each_child or perf_event_for_each as described
2789 * for perf_event_disable.
2791 static void _perf_event_enable(struct perf_event *event)
2793 struct perf_event_context *ctx = event->ctx;
2795 raw_spin_lock_irq(&ctx->lock);
2796 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2797 event->state < PERF_EVENT_STATE_ERROR) {
2798 raw_spin_unlock_irq(&ctx->lock);
2803 * If the event is in error state, clear that first.
2805 * That way, if we see the event in error state below, we know that it
2806 * has gone back into error state, as distinct from the task having
2807 * been scheduled away before the cross-call arrived.
2809 if (event->state == PERF_EVENT_STATE_ERROR)
2810 event->state = PERF_EVENT_STATE_OFF;
2811 raw_spin_unlock_irq(&ctx->lock);
2813 event_function_call(event, __perf_event_enable, NULL);
2817 * See perf_event_disable();
2819 void perf_event_enable(struct perf_event *event)
2821 struct perf_event_context *ctx;
2823 ctx = perf_event_ctx_lock(event);
2824 _perf_event_enable(event);
2825 perf_event_ctx_unlock(event, ctx);
2827 EXPORT_SYMBOL_GPL(perf_event_enable);
2829 struct stop_event_data {
2830 struct perf_event *event;
2831 unsigned int restart;
2834 static int __perf_event_stop(void *info)
2836 struct stop_event_data *sd = info;
2837 struct perf_event *event = sd->event;
2839 /* if it's already INACTIVE, do nothing */
2840 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2843 /* matches smp_wmb() in event_sched_in() */
2847 * There is a window with interrupts enabled before we get here,
2848 * so we need to check again lest we try to stop another CPU's event.
2850 if (READ_ONCE(event->oncpu) != smp_processor_id())
2853 event->pmu->stop(event, PERF_EF_UPDATE);
2856 * May race with the actual stop (through perf_pmu_output_stop()),
2857 * but it is only used for events with AUX ring buffer, and such
2858 * events will refuse to restart because of rb::aux_mmap_count==0,
2859 * see comments in perf_aux_output_begin().
2861 * Since this is happening on an event-local CPU, no trace is lost
2865 event->pmu->start(event, 0);
2870 static int perf_event_stop(struct perf_event *event, int restart)
2872 struct stop_event_data sd = {
2879 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2882 /* matches smp_wmb() in event_sched_in() */
2886 * We only want to restart ACTIVE events, so if the event goes
2887 * inactive here (event->oncpu==-1), there's nothing more to do;
2888 * fall through with ret==-ENXIO.
2890 ret = cpu_function_call(READ_ONCE(event->oncpu),
2891 __perf_event_stop, &sd);
2892 } while (ret == -EAGAIN);
2898 * In order to contain the amount of racy and tricky in the address filter
2899 * configuration management, it is a two part process:
2901 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2902 * we update the addresses of corresponding vmas in
2903 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2904 * (p2) when an event is scheduled in (pmu::add), it calls
2905 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2906 * if the generation has changed since the previous call.
2908 * If (p1) happens while the event is active, we restart it to force (p2).
2910 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2911 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2913 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2914 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2916 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2919 void perf_event_addr_filters_sync(struct perf_event *event)
2921 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2923 if (!has_addr_filter(event))
2926 raw_spin_lock(&ifh->lock);
2927 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2928 event->pmu->addr_filters_sync(event);
2929 event->hw.addr_filters_gen = event->addr_filters_gen;
2931 raw_spin_unlock(&ifh->lock);
2933 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2935 static int _perf_event_refresh(struct perf_event *event, int refresh)
2938 * not supported on inherited events
2940 if (event->attr.inherit || !is_sampling_event(event))
2943 atomic_add(refresh, &event->event_limit);
2944 _perf_event_enable(event);
2950 * See perf_event_disable()
2952 int perf_event_refresh(struct perf_event *event, int refresh)
2954 struct perf_event_context *ctx;
2957 ctx = perf_event_ctx_lock(event);
2958 ret = _perf_event_refresh(event, refresh);
2959 perf_event_ctx_unlock(event, ctx);
2963 EXPORT_SYMBOL_GPL(perf_event_refresh);
2965 static int perf_event_modify_breakpoint(struct perf_event *bp,
2966 struct perf_event_attr *attr)
2970 _perf_event_disable(bp);
2972 err = modify_user_hw_breakpoint_check(bp, attr, true);
2974 if (!bp->attr.disabled)
2975 _perf_event_enable(bp);
2980 static int perf_event_modify_attr(struct perf_event *event,
2981 struct perf_event_attr *attr)
2983 if (event->attr.type != attr->type)
2986 switch (event->attr.type) {
2987 case PERF_TYPE_BREAKPOINT:
2988 return perf_event_modify_breakpoint(event, attr);
2990 /* Place holder for future additions. */
2995 static void ctx_sched_out(struct perf_event_context *ctx,
2996 struct perf_cpu_context *cpuctx,
2997 enum event_type_t event_type)
2999 struct perf_event *event, *tmp;
3000 int is_active = ctx->is_active;
3002 lockdep_assert_held(&ctx->lock);
3004 if (likely(!ctx->nr_events)) {
3006 * See __perf_remove_from_context().
3008 WARN_ON_ONCE(ctx->is_active);
3010 WARN_ON_ONCE(cpuctx->task_ctx);
3014 ctx->is_active &= ~event_type;
3015 if (!(ctx->is_active & EVENT_ALL))
3019 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3020 if (!ctx->is_active)
3021 cpuctx->task_ctx = NULL;
3025 * Always update time if it was set; not only when it changes.
3026 * Otherwise we can 'forget' to update time for any but the last
3027 * context we sched out. For example:
3029 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3030 * ctx_sched_out(.event_type = EVENT_PINNED)
3032 * would only update time for the pinned events.
3034 if (is_active & EVENT_TIME) {
3035 /* update (and stop) ctx time */
3036 update_context_time(ctx);
3037 update_cgrp_time_from_cpuctx(cpuctx);
3040 is_active ^= ctx->is_active; /* changed bits */
3042 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3046 * If we had been multiplexing, no rotations are necessary, now no events
3049 ctx->rotate_necessary = 0;
3051 perf_pmu_disable(ctx->pmu);
3052 if (is_active & EVENT_PINNED) {
3053 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3054 group_sched_out(event, cpuctx, ctx);
3057 if (is_active & EVENT_FLEXIBLE) {
3058 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3059 group_sched_out(event, cpuctx, ctx);
3061 perf_pmu_enable(ctx->pmu);
3065 * Test whether two contexts are equivalent, i.e. whether they have both been
3066 * cloned from the same version of the same context.
3068 * Equivalence is measured using a generation number in the context that is
3069 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3070 * and list_del_event().
3072 static int context_equiv(struct perf_event_context *ctx1,
3073 struct perf_event_context *ctx2)
3075 lockdep_assert_held(&ctx1->lock);
3076 lockdep_assert_held(&ctx2->lock);
3078 /* Pinning disables the swap optimization */
3079 if (ctx1->pin_count || ctx2->pin_count)
3082 /* If ctx1 is the parent of ctx2 */
3083 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3086 /* If ctx2 is the parent of ctx1 */
3087 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3091 * If ctx1 and ctx2 have the same parent; we flatten the parent
3092 * hierarchy, see perf_event_init_context().
3094 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3095 ctx1->parent_gen == ctx2->parent_gen)
3102 static void __perf_event_sync_stat(struct perf_event *event,
3103 struct perf_event *next_event)
3107 if (!event->attr.inherit_stat)
3111 * Update the event value, we cannot use perf_event_read()
3112 * because we're in the middle of a context switch and have IRQs
3113 * disabled, which upsets smp_call_function_single(), however
3114 * we know the event must be on the current CPU, therefore we
3115 * don't need to use it.
3117 if (event->state == PERF_EVENT_STATE_ACTIVE)
3118 event->pmu->read(event);
3120 perf_event_update_time(event);
3123 * In order to keep per-task stats reliable we need to flip the event
3124 * values when we flip the contexts.
3126 value = local64_read(&next_event->count);
3127 value = local64_xchg(&event->count, value);
3128 local64_set(&next_event->count, value);
3130 swap(event->total_time_enabled, next_event->total_time_enabled);
3131 swap(event->total_time_running, next_event->total_time_running);
3134 * Since we swizzled the values, update the user visible data too.
3136 perf_event_update_userpage(event);
3137 perf_event_update_userpage(next_event);
3140 static void perf_event_sync_stat(struct perf_event_context *ctx,
3141 struct perf_event_context *next_ctx)
3143 struct perf_event *event, *next_event;
3148 update_context_time(ctx);
3150 event = list_first_entry(&ctx->event_list,
3151 struct perf_event, event_entry);
3153 next_event = list_first_entry(&next_ctx->event_list,
3154 struct perf_event, event_entry);
3156 while (&event->event_entry != &ctx->event_list &&
3157 &next_event->event_entry != &next_ctx->event_list) {
3159 __perf_event_sync_stat(event, next_event);
3161 event = list_next_entry(event, event_entry);
3162 next_event = list_next_entry(next_event, event_entry);
3166 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3167 struct task_struct *next)
3169 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3170 struct perf_event_context *next_ctx;
3171 struct perf_event_context *parent, *next_parent;
3172 struct perf_cpu_context *cpuctx;
3178 cpuctx = __get_cpu_context(ctx);
3179 if (!cpuctx->task_ctx)
3183 next_ctx = next->perf_event_ctxp[ctxn];
3187 parent = rcu_dereference(ctx->parent_ctx);
3188 next_parent = rcu_dereference(next_ctx->parent_ctx);
3190 /* If neither context have a parent context; they cannot be clones. */
3191 if (!parent && !next_parent)
3194 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3196 * Looks like the two contexts are clones, so we might be
3197 * able to optimize the context switch. We lock both
3198 * contexts and check that they are clones under the
3199 * lock (including re-checking that neither has been
3200 * uncloned in the meantime). It doesn't matter which
3201 * order we take the locks because no other cpu could
3202 * be trying to lock both of these tasks.
3204 raw_spin_lock(&ctx->lock);
3205 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3206 if (context_equiv(ctx, next_ctx)) {
3207 WRITE_ONCE(ctx->task, next);
3208 WRITE_ONCE(next_ctx->task, task);
3210 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3213 * RCU_INIT_POINTER here is safe because we've not
3214 * modified the ctx and the above modification of
3215 * ctx->task and ctx->task_ctx_data are immaterial
3216 * since those values are always verified under
3217 * ctx->lock which we're now holding.
3219 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3220 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3224 perf_event_sync_stat(ctx, next_ctx);
3226 raw_spin_unlock(&next_ctx->lock);
3227 raw_spin_unlock(&ctx->lock);
3233 raw_spin_lock(&ctx->lock);
3234 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3235 raw_spin_unlock(&ctx->lock);
3239 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3241 void perf_sched_cb_dec(struct pmu *pmu)
3243 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3245 this_cpu_dec(perf_sched_cb_usages);
3247 if (!--cpuctx->sched_cb_usage)
3248 list_del(&cpuctx->sched_cb_entry);
3252 void perf_sched_cb_inc(struct pmu *pmu)
3254 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3256 if (!cpuctx->sched_cb_usage++)
3257 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3259 this_cpu_inc(perf_sched_cb_usages);
3263 * This function provides the context switch callback to the lower code
3264 * layer. It is invoked ONLY when the context switch callback is enabled.
3266 * This callback is relevant even to per-cpu events; for example multi event
3267 * PEBS requires this to provide PID/TID information. This requires we flush
3268 * all queued PEBS records before we context switch to a new task.
3270 static void perf_pmu_sched_task(struct task_struct *prev,
3271 struct task_struct *next,
3274 struct perf_cpu_context *cpuctx;
3280 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3281 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3283 if (WARN_ON_ONCE(!pmu->sched_task))
3286 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3287 perf_pmu_disable(pmu);
3289 pmu->sched_task(cpuctx->task_ctx, sched_in);
3291 perf_pmu_enable(pmu);
3292 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3296 static void perf_event_switch(struct task_struct *task,
3297 struct task_struct *next_prev, bool sched_in);
3299 #define for_each_task_context_nr(ctxn) \
3300 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3303 * Called from scheduler to remove the events of the current task,
3304 * with interrupts disabled.
3306 * We stop each event and update the event value in event->count.
3308 * This does not protect us against NMI, but disable()
3309 * sets the disabled bit in the control field of event _before_
3310 * accessing the event control register. If a NMI hits, then it will
3311 * not restart the event.
3313 void __perf_event_task_sched_out(struct task_struct *task,
3314 struct task_struct *next)
3318 if (__this_cpu_read(perf_sched_cb_usages))
3319 perf_pmu_sched_task(task, next, false);
3321 if (atomic_read(&nr_switch_events))
3322 perf_event_switch(task, next, false);
3324 for_each_task_context_nr(ctxn)
3325 perf_event_context_sched_out(task, ctxn, next);
3328 * if cgroup events exist on this CPU, then we need
3329 * to check if we have to switch out PMU state.
3330 * cgroup event are system-wide mode only
3332 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3333 perf_cgroup_sched_out(task, next);
3337 * Called with IRQs disabled
3339 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3340 enum event_type_t event_type)
3342 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3345 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3346 int (*func)(struct perf_event *, void *), void *data)
3348 struct perf_event **evt, *evt1, *evt2;
3351 evt1 = perf_event_groups_first(groups, -1);
3352 evt2 = perf_event_groups_first(groups, cpu);
3354 while (evt1 || evt2) {
3356 if (evt1->group_index < evt2->group_index)
3366 ret = func(*evt, data);
3370 *evt = perf_event_groups_next(*evt);
3376 struct sched_in_data {
3377 struct perf_event_context *ctx;
3378 struct perf_cpu_context *cpuctx;
3382 static int pinned_sched_in(struct perf_event *event, void *data)
3384 struct sched_in_data *sid = data;
3386 if (event->state <= PERF_EVENT_STATE_OFF)
3389 if (!event_filter_match(event))
3392 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3393 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3394 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3398 * If this pinned group hasn't been scheduled,
3399 * put it in error state.
3401 if (event->state == PERF_EVENT_STATE_INACTIVE)
3402 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3407 static int flexible_sched_in(struct perf_event *event, void *data)
3409 struct sched_in_data *sid = data;
3411 if (event->state <= PERF_EVENT_STATE_OFF)
3414 if (!event_filter_match(event))
3417 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3418 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3420 sid->can_add_hw = 0;
3421 sid->ctx->rotate_necessary = 1;
3424 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3431 ctx_pinned_sched_in(struct perf_event_context *ctx,
3432 struct perf_cpu_context *cpuctx)
3434 struct sched_in_data sid = {
3440 visit_groups_merge(&ctx->pinned_groups,
3442 pinned_sched_in, &sid);
3446 ctx_flexible_sched_in(struct perf_event_context *ctx,
3447 struct perf_cpu_context *cpuctx)
3449 struct sched_in_data sid = {
3455 visit_groups_merge(&ctx->flexible_groups,
3457 flexible_sched_in, &sid);
3461 ctx_sched_in(struct perf_event_context *ctx,
3462 struct perf_cpu_context *cpuctx,
3463 enum event_type_t event_type,
3464 struct task_struct *task)
3466 int is_active = ctx->is_active;
3469 lockdep_assert_held(&ctx->lock);
3471 if (likely(!ctx->nr_events))
3474 ctx->is_active |= (event_type | EVENT_TIME);
3477 cpuctx->task_ctx = ctx;
3479 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3482 is_active ^= ctx->is_active; /* changed bits */
3484 if (is_active & EVENT_TIME) {
3485 /* start ctx time */
3487 ctx->timestamp = now;
3488 perf_cgroup_set_timestamp(task, ctx);
3492 * First go through the list and put on any pinned groups
3493 * in order to give them the best chance of going on.
3495 if (is_active & EVENT_PINNED)
3496 ctx_pinned_sched_in(ctx, cpuctx);
3498 /* Then walk through the lower prio flexible groups */
3499 if (is_active & EVENT_FLEXIBLE)
3500 ctx_flexible_sched_in(ctx, cpuctx);
3503 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3504 enum event_type_t event_type,
3505 struct task_struct *task)
3507 struct perf_event_context *ctx = &cpuctx->ctx;
3509 ctx_sched_in(ctx, cpuctx, event_type, task);
3512 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3513 struct task_struct *task)
3515 struct perf_cpu_context *cpuctx;
3517 cpuctx = __get_cpu_context(ctx);
3518 if (cpuctx->task_ctx == ctx)
3521 perf_ctx_lock(cpuctx, ctx);
3523 * We must check ctx->nr_events while holding ctx->lock, such
3524 * that we serialize against perf_install_in_context().
3526 if (!ctx->nr_events)
3529 perf_pmu_disable(ctx->pmu);
3531 * We want to keep the following priority order:
3532 * cpu pinned (that don't need to move), task pinned,
3533 * cpu flexible, task flexible.
3535 * However, if task's ctx is not carrying any pinned
3536 * events, no need to flip the cpuctx's events around.
3538 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3539 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3540 perf_event_sched_in(cpuctx, ctx, task);
3541 perf_pmu_enable(ctx->pmu);
3544 perf_ctx_unlock(cpuctx, ctx);
3548 * Called from scheduler to add the events of the current task
3549 * with interrupts disabled.
3551 * We restore the event value and then enable it.
3553 * This does not protect us against NMI, but enable()
3554 * sets the enabled bit in the control field of event _before_
3555 * accessing the event control register. If a NMI hits, then it will
3556 * keep the event running.
3558 void __perf_event_task_sched_in(struct task_struct *prev,
3559 struct task_struct *task)
3561 struct perf_event_context *ctx;
3565 * If cgroup events exist on this CPU, then we need to check if we have
3566 * to switch in PMU state; cgroup event are system-wide mode only.
3568 * Since cgroup events are CPU events, we must schedule these in before
3569 * we schedule in the task events.
3571 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3572 perf_cgroup_sched_in(prev, task);
3574 for_each_task_context_nr(ctxn) {
3575 ctx = task->perf_event_ctxp[ctxn];
3579 perf_event_context_sched_in(ctx, task);
3582 if (atomic_read(&nr_switch_events))
3583 perf_event_switch(task, prev, true);
3585 if (__this_cpu_read(perf_sched_cb_usages))
3586 perf_pmu_sched_task(prev, task, true);
3589 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3591 u64 frequency = event->attr.sample_freq;
3592 u64 sec = NSEC_PER_SEC;
3593 u64 divisor, dividend;
3595 int count_fls, nsec_fls, frequency_fls, sec_fls;
3597 count_fls = fls64(count);
3598 nsec_fls = fls64(nsec);
3599 frequency_fls = fls64(frequency);
3603 * We got @count in @nsec, with a target of sample_freq HZ
3604 * the target period becomes:
3607 * period = -------------------
3608 * @nsec * sample_freq
3613 * Reduce accuracy by one bit such that @a and @b converge
3614 * to a similar magnitude.
3616 #define REDUCE_FLS(a, b) \
3618 if (a##_fls > b##_fls) { \
3628 * Reduce accuracy until either term fits in a u64, then proceed with
3629 * the other, so that finally we can do a u64/u64 division.
3631 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3632 REDUCE_FLS(nsec, frequency);
3633 REDUCE_FLS(sec, count);
3636 if (count_fls + sec_fls > 64) {
3637 divisor = nsec * frequency;
3639 while (count_fls + sec_fls > 64) {
3640 REDUCE_FLS(count, sec);
3644 dividend = count * sec;
3646 dividend = count * sec;
3648 while (nsec_fls + frequency_fls > 64) {
3649 REDUCE_FLS(nsec, frequency);
3653 divisor = nsec * frequency;
3659 return div64_u64(dividend, divisor);
3662 static DEFINE_PER_CPU(int, perf_throttled_count);
3663 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3665 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3667 struct hw_perf_event *hwc = &event->hw;
3668 s64 period, sample_period;
3671 period = perf_calculate_period(event, nsec, count);
3673 delta = (s64)(period - hwc->sample_period);
3674 delta = (delta + 7) / 8; /* low pass filter */
3676 sample_period = hwc->sample_period + delta;
3681 hwc->sample_period = sample_period;
3683 if (local64_read(&hwc->period_left) > 8*sample_period) {
3685 event->pmu->stop(event, PERF_EF_UPDATE);
3687 local64_set(&hwc->period_left, 0);
3690 event->pmu->start(event, PERF_EF_RELOAD);
3695 * combine freq adjustment with unthrottling to avoid two passes over the
3696 * events. At the same time, make sure, having freq events does not change
3697 * the rate of unthrottling as that would introduce bias.
3699 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3702 struct perf_event *event;
3703 struct hw_perf_event *hwc;
3704 u64 now, period = TICK_NSEC;
3708 * only need to iterate over all events iff:
3709 * - context have events in frequency mode (needs freq adjust)
3710 * - there are events to unthrottle on this cpu
3712 if (!(ctx->nr_freq || needs_unthr))
3715 raw_spin_lock(&ctx->lock);
3716 perf_pmu_disable(ctx->pmu);
3718 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3719 if (event->state != PERF_EVENT_STATE_ACTIVE)
3722 if (!event_filter_match(event))
3725 perf_pmu_disable(event->pmu);
3729 if (hwc->interrupts == MAX_INTERRUPTS) {
3730 hwc->interrupts = 0;
3731 perf_log_throttle(event, 1);
3732 event->pmu->start(event, 0);
3735 if (!event->attr.freq || !event->attr.sample_freq)
3739 * stop the event and update event->count
3741 event->pmu->stop(event, PERF_EF_UPDATE);
3743 now = local64_read(&event->count);
3744 delta = now - hwc->freq_count_stamp;
3745 hwc->freq_count_stamp = now;
3749 * reload only if value has changed
3750 * we have stopped the event so tell that
3751 * to perf_adjust_period() to avoid stopping it
3755 perf_adjust_period(event, period, delta, false);
3757 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3759 perf_pmu_enable(event->pmu);
3762 perf_pmu_enable(ctx->pmu);
3763 raw_spin_unlock(&ctx->lock);
3767 * Move @event to the tail of the @ctx's elegible events.
3769 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3772 * Rotate the first entry last of non-pinned groups. Rotation might be
3773 * disabled by the inheritance code.
3775 if (ctx->rotate_disable)
3778 perf_event_groups_delete(&ctx->flexible_groups, event);
3779 perf_event_groups_insert(&ctx->flexible_groups, event);
3782 static inline struct perf_event *
3783 ctx_first_active(struct perf_event_context *ctx)
3785 return list_first_entry_or_null(&ctx->flexible_active,
3786 struct perf_event, active_list);
3789 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3791 struct perf_event *cpu_event = NULL, *task_event = NULL;
3792 struct perf_event_context *task_ctx = NULL;
3793 int cpu_rotate, task_rotate;
3796 * Since we run this from IRQ context, nobody can install new
3797 * events, thus the event count values are stable.
3800 cpu_rotate = cpuctx->ctx.rotate_necessary;
3801 task_ctx = cpuctx->task_ctx;
3802 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3804 if (!(cpu_rotate || task_rotate))
3807 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3808 perf_pmu_disable(cpuctx->ctx.pmu);
3811 task_event = ctx_first_active(task_ctx);
3813 cpu_event = ctx_first_active(&cpuctx->ctx);
3816 * As per the order given at ctx_resched() first 'pop' task flexible
3817 * and then, if needed CPU flexible.
3819 if (task_event || (task_ctx && cpu_event))
3820 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3822 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3825 rotate_ctx(task_ctx, task_event);
3827 rotate_ctx(&cpuctx->ctx, cpu_event);
3829 perf_event_sched_in(cpuctx, task_ctx, current);
3831 perf_pmu_enable(cpuctx->ctx.pmu);
3832 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3837 void perf_event_task_tick(void)
3839 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3840 struct perf_event_context *ctx, *tmp;
3843 lockdep_assert_irqs_disabled();
3845 __this_cpu_inc(perf_throttled_seq);
3846 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3847 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3849 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3850 perf_adjust_freq_unthr_context(ctx, throttled);
3853 static int event_enable_on_exec(struct perf_event *event,
3854 struct perf_event_context *ctx)
3856 if (!event->attr.enable_on_exec)
3859 event->attr.enable_on_exec = 0;
3860 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3863 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3869 * Enable all of a task's events that have been marked enable-on-exec.
3870 * This expects task == current.
3872 static void perf_event_enable_on_exec(int ctxn)
3874 struct perf_event_context *ctx, *clone_ctx = NULL;
3875 enum event_type_t event_type = 0;
3876 struct perf_cpu_context *cpuctx;
3877 struct perf_event *event;
3878 unsigned long flags;
3881 local_irq_save(flags);
3882 ctx = current->perf_event_ctxp[ctxn];
3883 if (!ctx || !ctx->nr_events)
3886 cpuctx = __get_cpu_context(ctx);
3887 perf_ctx_lock(cpuctx, ctx);
3888 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3889 list_for_each_entry(event, &ctx->event_list, event_entry) {
3890 enabled |= event_enable_on_exec(event, ctx);
3891 event_type |= get_event_type(event);
3895 * Unclone and reschedule this context if we enabled any event.
3898 clone_ctx = unclone_ctx(ctx);
3899 ctx_resched(cpuctx, ctx, event_type);
3901 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3903 perf_ctx_unlock(cpuctx, ctx);
3906 local_irq_restore(flags);
3912 struct perf_read_data {
3913 struct perf_event *event;
3918 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3920 u16 local_pkg, event_pkg;
3922 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3923 int local_cpu = smp_processor_id();
3925 event_pkg = topology_physical_package_id(event_cpu);
3926 local_pkg = topology_physical_package_id(local_cpu);
3928 if (event_pkg == local_pkg)
3936 * Cross CPU call to read the hardware event
3938 static void __perf_event_read(void *info)
3940 struct perf_read_data *data = info;
3941 struct perf_event *sub, *event = data->event;
3942 struct perf_event_context *ctx = event->ctx;
3943 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3944 struct pmu *pmu = event->pmu;
3947 * If this is a task context, we need to check whether it is
3948 * the current task context of this cpu. If not it has been
3949 * scheduled out before the smp call arrived. In that case
3950 * event->count would have been updated to a recent sample
3951 * when the event was scheduled out.
3953 if (ctx->task && cpuctx->task_ctx != ctx)
3956 raw_spin_lock(&ctx->lock);
3957 if (ctx->is_active & EVENT_TIME) {
3958 update_context_time(ctx);
3959 update_cgrp_time_from_event(event);
3962 perf_event_update_time(event);
3964 perf_event_update_sibling_time(event);
3966 if (event->state != PERF_EVENT_STATE_ACTIVE)
3975 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3979 for_each_sibling_event(sub, event) {
3980 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3982 * Use sibling's PMU rather than @event's since
3983 * sibling could be on different (eg: software) PMU.
3985 sub->pmu->read(sub);
3989 data->ret = pmu->commit_txn(pmu);
3992 raw_spin_unlock(&ctx->lock);
3995 static inline u64 perf_event_count(struct perf_event *event)
3997 return local64_read(&event->count) + atomic64_read(&event->child_count);
4001 * NMI-safe method to read a local event, that is an event that
4003 * - either for the current task, or for this CPU
4004 * - does not have inherit set, for inherited task events
4005 * will not be local and we cannot read them atomically
4006 * - must not have a pmu::count method
4008 int perf_event_read_local(struct perf_event *event, u64 *value,
4009 u64 *enabled, u64 *running)
4011 unsigned long flags;
4015 * Disabling interrupts avoids all counter scheduling (context
4016 * switches, timer based rotation and IPIs).
4018 local_irq_save(flags);
4021 * It must not be an event with inherit set, we cannot read
4022 * all child counters from atomic context.
4024 if (event->attr.inherit) {
4029 /* If this is a per-task event, it must be for current */
4030 if ((event->attach_state & PERF_ATTACH_TASK) &&
4031 event->hw.target != current) {
4036 /* If this is a per-CPU event, it must be for this CPU */
4037 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4038 event->cpu != smp_processor_id()) {
4043 /* If this is a pinned event it must be running on this CPU */
4044 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4050 * If the event is currently on this CPU, its either a per-task event,
4051 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4054 if (event->oncpu == smp_processor_id())
4055 event->pmu->read(event);
4057 *value = local64_read(&event->count);
4058 if (enabled || running) {
4059 u64 now = event->shadow_ctx_time + perf_clock();
4060 u64 __enabled, __running;
4062 __perf_update_times(event, now, &__enabled, &__running);
4064 *enabled = __enabled;
4066 *running = __running;
4069 local_irq_restore(flags);
4074 static int perf_event_read(struct perf_event *event, bool group)
4076 enum perf_event_state state = READ_ONCE(event->state);
4077 int event_cpu, ret = 0;
4080 * If event is enabled and currently active on a CPU, update the
4081 * value in the event structure:
4084 if (state == PERF_EVENT_STATE_ACTIVE) {
4085 struct perf_read_data data;
4088 * Orders the ->state and ->oncpu loads such that if we see
4089 * ACTIVE we must also see the right ->oncpu.
4091 * Matches the smp_wmb() from event_sched_in().
4095 event_cpu = READ_ONCE(event->oncpu);
4096 if ((unsigned)event_cpu >= nr_cpu_ids)
4099 data = (struct perf_read_data){
4106 event_cpu = __perf_event_read_cpu(event, event_cpu);
4109 * Purposely ignore the smp_call_function_single() return
4112 * If event_cpu isn't a valid CPU it means the event got
4113 * scheduled out and that will have updated the event count.
4115 * Therefore, either way, we'll have an up-to-date event count
4118 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4122 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4123 struct perf_event_context *ctx = event->ctx;
4124 unsigned long flags;
4126 raw_spin_lock_irqsave(&ctx->lock, flags);
4127 state = event->state;
4128 if (state != PERF_EVENT_STATE_INACTIVE) {
4129 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4134 * May read while context is not active (e.g., thread is
4135 * blocked), in that case we cannot update context time
4137 if (ctx->is_active & EVENT_TIME) {
4138 update_context_time(ctx);
4139 update_cgrp_time_from_event(event);
4142 perf_event_update_time(event);
4144 perf_event_update_sibling_time(event);
4145 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4152 * Initialize the perf_event context in a task_struct:
4154 static void __perf_event_init_context(struct perf_event_context *ctx)
4156 raw_spin_lock_init(&ctx->lock);
4157 mutex_init(&ctx->mutex);
4158 INIT_LIST_HEAD(&ctx->active_ctx_list);
4159 perf_event_groups_init(&ctx->pinned_groups);
4160 perf_event_groups_init(&ctx->flexible_groups);
4161 INIT_LIST_HEAD(&ctx->event_list);
4162 INIT_LIST_HEAD(&ctx->pinned_active);
4163 INIT_LIST_HEAD(&ctx->flexible_active);
4164 refcount_set(&ctx->refcount, 1);
4167 static struct perf_event_context *
4168 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4170 struct perf_event_context *ctx;
4172 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4176 __perf_event_init_context(ctx);
4178 ctx->task = get_task_struct(task);
4184 static struct task_struct *
4185 find_lively_task_by_vpid(pid_t vpid)
4187 struct task_struct *task;
4193 task = find_task_by_vpid(vpid);
4195 get_task_struct(task);
4199 return ERR_PTR(-ESRCH);
4205 * Returns a matching context with refcount and pincount.
4207 static struct perf_event_context *
4208 find_get_context(struct pmu *pmu, struct task_struct *task,
4209 struct perf_event *event)
4211 struct perf_event_context *ctx, *clone_ctx = NULL;
4212 struct perf_cpu_context *cpuctx;
4213 void *task_ctx_data = NULL;
4214 unsigned long flags;
4216 int cpu = event->cpu;
4219 /* Must be root to operate on a CPU event: */
4220 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4221 return ERR_PTR(-EACCES);
4223 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4232 ctxn = pmu->task_ctx_nr;
4236 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4237 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4238 if (!task_ctx_data) {
4245 ctx = perf_lock_task_context(task, ctxn, &flags);
4247 clone_ctx = unclone_ctx(ctx);
4250 if (task_ctx_data && !ctx->task_ctx_data) {
4251 ctx->task_ctx_data = task_ctx_data;
4252 task_ctx_data = NULL;
4254 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4259 ctx = alloc_perf_context(pmu, task);
4264 if (task_ctx_data) {
4265 ctx->task_ctx_data = task_ctx_data;
4266 task_ctx_data = NULL;
4270 mutex_lock(&task->perf_event_mutex);
4272 * If it has already passed perf_event_exit_task().
4273 * we must see PF_EXITING, it takes this mutex too.
4275 if (task->flags & PF_EXITING)
4277 else if (task->perf_event_ctxp[ctxn])
4282 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4284 mutex_unlock(&task->perf_event_mutex);
4286 if (unlikely(err)) {
4295 kfree(task_ctx_data);
4299 kfree(task_ctx_data);
4300 return ERR_PTR(err);
4303 static void perf_event_free_filter(struct perf_event *event);
4304 static void perf_event_free_bpf_prog(struct perf_event *event);
4306 static void free_event_rcu(struct rcu_head *head)
4308 struct perf_event *event;
4310 event = container_of(head, struct perf_event, rcu_head);
4312 put_pid_ns(event->ns);
4313 perf_event_free_filter(event);
4317 static void ring_buffer_attach(struct perf_event *event,
4318 struct ring_buffer *rb);
4320 static void detach_sb_event(struct perf_event *event)
4322 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4324 raw_spin_lock(&pel->lock);
4325 list_del_rcu(&event->sb_list);
4326 raw_spin_unlock(&pel->lock);
4329 static bool is_sb_event(struct perf_event *event)
4331 struct perf_event_attr *attr = &event->attr;
4336 if (event->attach_state & PERF_ATTACH_TASK)
4339 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4340 attr->comm || attr->comm_exec ||
4341 attr->task || attr->ksymbol ||
4342 attr->context_switch ||
4348 static void unaccount_pmu_sb_event(struct perf_event *event)
4350 if (is_sb_event(event))
4351 detach_sb_event(event);
4354 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4359 if (is_cgroup_event(event))
4360 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4363 #ifdef CONFIG_NO_HZ_FULL
4364 static DEFINE_SPINLOCK(nr_freq_lock);
4367 static void unaccount_freq_event_nohz(void)
4369 #ifdef CONFIG_NO_HZ_FULL
4370 spin_lock(&nr_freq_lock);
4371 if (atomic_dec_and_test(&nr_freq_events))
4372 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4373 spin_unlock(&nr_freq_lock);
4377 static void unaccount_freq_event(void)
4379 if (tick_nohz_full_enabled())
4380 unaccount_freq_event_nohz();
4382 atomic_dec(&nr_freq_events);
4385 static void unaccount_event(struct perf_event *event)
4392 if (event->attach_state & PERF_ATTACH_TASK)
4394 if (event->attr.mmap || event->attr.mmap_data)
4395 atomic_dec(&nr_mmap_events);
4396 if (event->attr.comm)
4397 atomic_dec(&nr_comm_events);
4398 if (event->attr.namespaces)
4399 atomic_dec(&nr_namespaces_events);
4400 if (event->attr.task)
4401 atomic_dec(&nr_task_events);
4402 if (event->attr.freq)
4403 unaccount_freq_event();
4404 if (event->attr.context_switch) {
4406 atomic_dec(&nr_switch_events);
4408 if (is_cgroup_event(event))
4410 if (has_branch_stack(event))
4412 if (event->attr.ksymbol)
4413 atomic_dec(&nr_ksymbol_events);
4414 if (event->attr.bpf_event)
4415 atomic_dec(&nr_bpf_events);
4418 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4419 schedule_delayed_work(&perf_sched_work, HZ);
4422 unaccount_event_cpu(event, event->cpu);
4424 unaccount_pmu_sb_event(event);
4427 static void perf_sched_delayed(struct work_struct *work)
4429 mutex_lock(&perf_sched_mutex);
4430 if (atomic_dec_and_test(&perf_sched_count))
4431 static_branch_disable(&perf_sched_events);
4432 mutex_unlock(&perf_sched_mutex);
4436 * The following implement mutual exclusion of events on "exclusive" pmus
4437 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4438 * at a time, so we disallow creating events that might conflict, namely:
4440 * 1) cpu-wide events in the presence of per-task events,
4441 * 2) per-task events in the presence of cpu-wide events,
4442 * 3) two matching events on the same context.
4444 * The former two cases are handled in the allocation path (perf_event_alloc(),
4445 * _free_event()), the latter -- before the first perf_install_in_context().
4447 static int exclusive_event_init(struct perf_event *event)
4449 struct pmu *pmu = event->pmu;
4451 if (!is_exclusive_pmu(pmu))
4455 * Prevent co-existence of per-task and cpu-wide events on the
4456 * same exclusive pmu.
4458 * Negative pmu::exclusive_cnt means there are cpu-wide
4459 * events on this "exclusive" pmu, positive means there are
4462 * Since this is called in perf_event_alloc() path, event::ctx
4463 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4464 * to mean "per-task event", because unlike other attach states it
4465 * never gets cleared.
4467 if (event->attach_state & PERF_ATTACH_TASK) {
4468 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4471 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4478 static void exclusive_event_destroy(struct perf_event *event)
4480 struct pmu *pmu = event->pmu;
4482 if (!is_exclusive_pmu(pmu))
4485 /* see comment in exclusive_event_init() */
4486 if (event->attach_state & PERF_ATTACH_TASK)
4487 atomic_dec(&pmu->exclusive_cnt);
4489 atomic_inc(&pmu->exclusive_cnt);
4492 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4494 if ((e1->pmu == e2->pmu) &&
4495 (e1->cpu == e2->cpu ||
4502 static bool exclusive_event_installable(struct perf_event *event,
4503 struct perf_event_context *ctx)
4505 struct perf_event *iter_event;
4506 struct pmu *pmu = event->pmu;
4508 lockdep_assert_held(&ctx->mutex);
4510 if (!is_exclusive_pmu(pmu))
4513 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4514 if (exclusive_event_match(iter_event, event))
4521 static void perf_addr_filters_splice(struct perf_event *event,
4522 struct list_head *head);
4524 static void _free_event(struct perf_event *event)
4526 irq_work_sync(&event->pending);
4528 unaccount_event(event);
4532 * Can happen when we close an event with re-directed output.
4534 * Since we have a 0 refcount, perf_mmap_close() will skip
4535 * over us; possibly making our ring_buffer_put() the last.
4537 mutex_lock(&event->mmap_mutex);
4538 ring_buffer_attach(event, NULL);
4539 mutex_unlock(&event->mmap_mutex);
4542 if (is_cgroup_event(event))
4543 perf_detach_cgroup(event);
4545 if (!event->parent) {
4546 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4547 put_callchain_buffers();
4550 perf_event_free_bpf_prog(event);
4551 perf_addr_filters_splice(event, NULL);
4552 kfree(event->addr_filter_ranges);
4555 event->destroy(event);
4558 * Must be after ->destroy(), due to uprobe_perf_close() using
4561 if (event->hw.target)
4562 put_task_struct(event->hw.target);
4565 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4566 * all task references must be cleaned up.
4569 put_ctx(event->ctx);
4571 exclusive_event_destroy(event);
4572 module_put(event->pmu->module);
4574 call_rcu(&event->rcu_head, free_event_rcu);
4578 * Used to free events which have a known refcount of 1, such as in error paths
4579 * where the event isn't exposed yet and inherited events.
4581 static void free_event(struct perf_event *event)
4583 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4584 "unexpected event refcount: %ld; ptr=%p\n",
4585 atomic_long_read(&event->refcount), event)) {
4586 /* leak to avoid use-after-free */
4594 * Remove user event from the owner task.
4596 static void perf_remove_from_owner(struct perf_event *event)
4598 struct task_struct *owner;
4602 * Matches the smp_store_release() in perf_event_exit_task(). If we
4603 * observe !owner it means the list deletion is complete and we can
4604 * indeed free this event, otherwise we need to serialize on
4605 * owner->perf_event_mutex.
4607 owner = READ_ONCE(event->owner);
4610 * Since delayed_put_task_struct() also drops the last
4611 * task reference we can safely take a new reference
4612 * while holding the rcu_read_lock().
4614 get_task_struct(owner);
4620 * If we're here through perf_event_exit_task() we're already
4621 * holding ctx->mutex which would be an inversion wrt. the
4622 * normal lock order.
4624 * However we can safely take this lock because its the child
4627 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4630 * We have to re-check the event->owner field, if it is cleared
4631 * we raced with perf_event_exit_task(), acquiring the mutex
4632 * ensured they're done, and we can proceed with freeing the
4636 list_del_init(&event->owner_entry);
4637 smp_store_release(&event->owner, NULL);
4639 mutex_unlock(&owner->perf_event_mutex);
4640 put_task_struct(owner);
4644 static void put_event(struct perf_event *event)
4646 if (!atomic_long_dec_and_test(&event->refcount))
4653 * Kill an event dead; while event:refcount will preserve the event
4654 * object, it will not preserve its functionality. Once the last 'user'
4655 * gives up the object, we'll destroy the thing.
4657 int perf_event_release_kernel(struct perf_event *event)
4659 struct perf_event_context *ctx = event->ctx;
4660 struct perf_event *child, *tmp;
4661 LIST_HEAD(free_list);
4664 * If we got here through err_file: fput(event_file); we will not have
4665 * attached to a context yet.
4668 WARN_ON_ONCE(event->attach_state &
4669 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4673 if (!is_kernel_event(event))
4674 perf_remove_from_owner(event);
4676 ctx = perf_event_ctx_lock(event);
4677 WARN_ON_ONCE(ctx->parent_ctx);
4678 perf_remove_from_context(event, DETACH_GROUP);
4680 raw_spin_lock_irq(&ctx->lock);
4682 * Mark this event as STATE_DEAD, there is no external reference to it
4685 * Anybody acquiring event->child_mutex after the below loop _must_
4686 * also see this, most importantly inherit_event() which will avoid
4687 * placing more children on the list.
4689 * Thus this guarantees that we will in fact observe and kill _ALL_
4692 event->state = PERF_EVENT_STATE_DEAD;
4693 raw_spin_unlock_irq(&ctx->lock);
4695 perf_event_ctx_unlock(event, ctx);
4698 mutex_lock(&event->child_mutex);
4699 list_for_each_entry(child, &event->child_list, child_list) {
4702 * Cannot change, child events are not migrated, see the
4703 * comment with perf_event_ctx_lock_nested().
4705 ctx = READ_ONCE(child->ctx);
4707 * Since child_mutex nests inside ctx::mutex, we must jump
4708 * through hoops. We start by grabbing a reference on the ctx.
4710 * Since the event cannot get freed while we hold the
4711 * child_mutex, the context must also exist and have a !0
4717 * Now that we have a ctx ref, we can drop child_mutex, and
4718 * acquire ctx::mutex without fear of it going away. Then we
4719 * can re-acquire child_mutex.
4721 mutex_unlock(&event->child_mutex);
4722 mutex_lock(&ctx->mutex);
4723 mutex_lock(&event->child_mutex);
4726 * Now that we hold ctx::mutex and child_mutex, revalidate our
4727 * state, if child is still the first entry, it didn't get freed
4728 * and we can continue doing so.
4730 tmp = list_first_entry_or_null(&event->child_list,
4731 struct perf_event, child_list);
4733 perf_remove_from_context(child, DETACH_GROUP);
4734 list_move(&child->child_list, &free_list);
4736 * This matches the refcount bump in inherit_event();
4737 * this can't be the last reference.
4742 mutex_unlock(&event->child_mutex);
4743 mutex_unlock(&ctx->mutex);
4747 mutex_unlock(&event->child_mutex);
4749 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4750 void *var = &child->ctx->refcount;
4752 list_del(&child->child_list);
4756 * Wake any perf_event_free_task() waiting for this event to be
4759 smp_mb(); /* pairs with wait_var_event() */
4764 put_event(event); /* Must be the 'last' reference */
4767 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4770 * Called when the last reference to the file is gone.
4772 static int perf_release(struct inode *inode, struct file *file)
4774 perf_event_release_kernel(file->private_data);
4778 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4780 struct perf_event *child;
4786 mutex_lock(&event->child_mutex);
4788 (void)perf_event_read(event, false);
4789 total += perf_event_count(event);
4791 *enabled += event->total_time_enabled +
4792 atomic64_read(&event->child_total_time_enabled);
4793 *running += event->total_time_running +
4794 atomic64_read(&event->child_total_time_running);
4796 list_for_each_entry(child, &event->child_list, child_list) {
4797 (void)perf_event_read(child, false);
4798 total += perf_event_count(child);
4799 *enabled += child->total_time_enabled;
4800 *running += child->total_time_running;
4802 mutex_unlock(&event->child_mutex);
4807 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4809 struct perf_event_context *ctx;
4812 ctx = perf_event_ctx_lock(event);
4813 count = __perf_event_read_value(event, enabled, running);
4814 perf_event_ctx_unlock(event, ctx);
4818 EXPORT_SYMBOL_GPL(perf_event_read_value);
4820 static int __perf_read_group_add(struct perf_event *leader,
4821 u64 read_format, u64 *values)
4823 struct perf_event_context *ctx = leader->ctx;
4824 struct perf_event *sub;
4825 unsigned long flags;
4826 int n = 1; /* skip @nr */
4829 ret = perf_event_read(leader, true);
4833 raw_spin_lock_irqsave(&ctx->lock, flags);
4836 * Since we co-schedule groups, {enabled,running} times of siblings
4837 * will be identical to those of the leader, so we only publish one
4840 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4841 values[n++] += leader->total_time_enabled +
4842 atomic64_read(&leader->child_total_time_enabled);
4845 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4846 values[n++] += leader->total_time_running +
4847 atomic64_read(&leader->child_total_time_running);
4851 * Write {count,id} tuples for every sibling.
4853 values[n++] += perf_event_count(leader);
4854 if (read_format & PERF_FORMAT_ID)
4855 values[n++] = primary_event_id(leader);
4857 for_each_sibling_event(sub, leader) {
4858 values[n++] += perf_event_count(sub);
4859 if (read_format & PERF_FORMAT_ID)
4860 values[n++] = primary_event_id(sub);
4863 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4867 static int perf_read_group(struct perf_event *event,
4868 u64 read_format, char __user *buf)
4870 struct perf_event *leader = event->group_leader, *child;
4871 struct perf_event_context *ctx = leader->ctx;
4875 lockdep_assert_held(&ctx->mutex);
4877 values = kzalloc(event->read_size, GFP_KERNEL);
4881 values[0] = 1 + leader->nr_siblings;
4884 * By locking the child_mutex of the leader we effectively
4885 * lock the child list of all siblings.. XXX explain how.
4887 mutex_lock(&leader->child_mutex);
4889 ret = __perf_read_group_add(leader, read_format, values);
4893 list_for_each_entry(child, &leader->child_list, child_list) {
4894 ret = __perf_read_group_add(child, read_format, values);
4899 mutex_unlock(&leader->child_mutex);
4901 ret = event->read_size;
4902 if (copy_to_user(buf, values, event->read_size))
4907 mutex_unlock(&leader->child_mutex);
4913 static int perf_read_one(struct perf_event *event,
4914 u64 read_format, char __user *buf)
4916 u64 enabled, running;
4920 values[n++] = __perf_event_read_value(event, &enabled, &running);
4921 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4922 values[n++] = enabled;
4923 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4924 values[n++] = running;
4925 if (read_format & PERF_FORMAT_ID)
4926 values[n++] = primary_event_id(event);
4928 if (copy_to_user(buf, values, n * sizeof(u64)))
4931 return n * sizeof(u64);
4934 static bool is_event_hup(struct perf_event *event)
4938 if (event->state > PERF_EVENT_STATE_EXIT)
4941 mutex_lock(&event->child_mutex);
4942 no_children = list_empty(&event->child_list);
4943 mutex_unlock(&event->child_mutex);
4948 * Read the performance event - simple non blocking version for now
4951 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4953 u64 read_format = event->attr.read_format;
4957 * Return end-of-file for a read on an event that is in
4958 * error state (i.e. because it was pinned but it couldn't be
4959 * scheduled on to the CPU at some point).
4961 if (event->state == PERF_EVENT_STATE_ERROR)
4964 if (count < event->read_size)
4967 WARN_ON_ONCE(event->ctx->parent_ctx);
4968 if (read_format & PERF_FORMAT_GROUP)
4969 ret = perf_read_group(event, read_format, buf);
4971 ret = perf_read_one(event, read_format, buf);
4977 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4979 struct perf_event *event = file->private_data;
4980 struct perf_event_context *ctx;
4983 ctx = perf_event_ctx_lock(event);
4984 ret = __perf_read(event, buf, count);
4985 perf_event_ctx_unlock(event, ctx);
4990 static __poll_t perf_poll(struct file *file, poll_table *wait)
4992 struct perf_event *event = file->private_data;
4993 struct ring_buffer *rb;
4994 __poll_t events = EPOLLHUP;
4996 poll_wait(file, &event->waitq, wait);
4998 if (is_event_hup(event))
5002 * Pin the event->rb by taking event->mmap_mutex; otherwise
5003 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5005 mutex_lock(&event->mmap_mutex);
5008 events = atomic_xchg(&rb->poll, 0);
5009 mutex_unlock(&event->mmap_mutex);
5013 static void _perf_event_reset(struct perf_event *event)
5015 (void)perf_event_read(event, false);
5016 local64_set(&event->count, 0);
5017 perf_event_update_userpage(event);
5021 * Holding the top-level event's child_mutex means that any
5022 * descendant process that has inherited this event will block
5023 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5024 * task existence requirements of perf_event_enable/disable.
5026 static void perf_event_for_each_child(struct perf_event *event,
5027 void (*func)(struct perf_event *))
5029 struct perf_event *child;
5031 WARN_ON_ONCE(event->ctx->parent_ctx);
5033 mutex_lock(&event->child_mutex);
5035 list_for_each_entry(child, &event->child_list, child_list)
5037 mutex_unlock(&event->child_mutex);
5040 static void perf_event_for_each(struct perf_event *event,
5041 void (*func)(struct perf_event *))
5043 struct perf_event_context *ctx = event->ctx;
5044 struct perf_event *sibling;
5046 lockdep_assert_held(&ctx->mutex);
5048 event = event->group_leader;
5050 perf_event_for_each_child(event, func);
5051 for_each_sibling_event(sibling, event)
5052 perf_event_for_each_child(sibling, func);
5055 static void __perf_event_period(struct perf_event *event,
5056 struct perf_cpu_context *cpuctx,
5057 struct perf_event_context *ctx,
5060 u64 value = *((u64 *)info);
5063 if (event->attr.freq) {
5064 event->attr.sample_freq = value;
5066 event->attr.sample_period = value;
5067 event->hw.sample_period = value;
5070 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5072 perf_pmu_disable(ctx->pmu);
5074 * We could be throttled; unthrottle now to avoid the tick
5075 * trying to unthrottle while we already re-started the event.
5077 if (event->hw.interrupts == MAX_INTERRUPTS) {
5078 event->hw.interrupts = 0;
5079 perf_log_throttle(event, 1);
5081 event->pmu->stop(event, PERF_EF_UPDATE);
5084 local64_set(&event->hw.period_left, 0);
5087 event->pmu->start(event, PERF_EF_RELOAD);
5088 perf_pmu_enable(ctx->pmu);
5092 static int perf_event_check_period(struct perf_event *event, u64 value)
5094 return event->pmu->check_period(event, value);
5097 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5101 if (!is_sampling_event(event))
5104 if (copy_from_user(&value, arg, sizeof(value)))
5110 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5113 if (perf_event_check_period(event, value))
5116 if (!event->attr.freq && (value & (1ULL << 63)))
5119 event_function_call(event, __perf_event_period, &value);
5124 static const struct file_operations perf_fops;
5126 static inline int perf_fget_light(int fd, struct fd *p)
5128 struct fd f = fdget(fd);
5132 if (f.file->f_op != &perf_fops) {
5140 static int perf_event_set_output(struct perf_event *event,
5141 struct perf_event *output_event);
5142 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5143 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5144 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5145 struct perf_event_attr *attr);
5147 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5149 void (*func)(struct perf_event *);
5153 case PERF_EVENT_IOC_ENABLE:
5154 func = _perf_event_enable;
5156 case PERF_EVENT_IOC_DISABLE:
5157 func = _perf_event_disable;
5159 case PERF_EVENT_IOC_RESET:
5160 func = _perf_event_reset;
5163 case PERF_EVENT_IOC_REFRESH:
5164 return _perf_event_refresh(event, arg);
5166 case PERF_EVENT_IOC_PERIOD:
5167 return perf_event_period(event, (u64 __user *)arg);
5169 case PERF_EVENT_IOC_ID:
5171 u64 id = primary_event_id(event);
5173 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5178 case PERF_EVENT_IOC_SET_OUTPUT:
5182 struct perf_event *output_event;
5184 ret = perf_fget_light(arg, &output);
5187 output_event = output.file->private_data;
5188 ret = perf_event_set_output(event, output_event);
5191 ret = perf_event_set_output(event, NULL);
5196 case PERF_EVENT_IOC_SET_FILTER:
5197 return perf_event_set_filter(event, (void __user *)arg);
5199 case PERF_EVENT_IOC_SET_BPF:
5200 return perf_event_set_bpf_prog(event, arg);
5202 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5203 struct ring_buffer *rb;
5206 rb = rcu_dereference(event->rb);
5207 if (!rb || !rb->nr_pages) {
5211 rb_toggle_paused(rb, !!arg);
5216 case PERF_EVENT_IOC_QUERY_BPF:
5217 return perf_event_query_prog_array(event, (void __user *)arg);
5219 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5220 struct perf_event_attr new_attr;
5221 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5227 return perf_event_modify_attr(event, &new_attr);
5233 if (flags & PERF_IOC_FLAG_GROUP)
5234 perf_event_for_each(event, func);
5236 perf_event_for_each_child(event, func);
5241 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5243 struct perf_event *event = file->private_data;
5244 struct perf_event_context *ctx;
5247 ctx = perf_event_ctx_lock(event);
5248 ret = _perf_ioctl(event, cmd, arg);
5249 perf_event_ctx_unlock(event, ctx);
5254 #ifdef CONFIG_COMPAT
5255 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5258 switch (_IOC_NR(cmd)) {
5259 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5260 case _IOC_NR(PERF_EVENT_IOC_ID):
5261 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5262 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5263 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5264 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5265 cmd &= ~IOCSIZE_MASK;
5266 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5270 return perf_ioctl(file, cmd, arg);
5273 # define perf_compat_ioctl NULL
5276 int perf_event_task_enable(void)
5278 struct perf_event_context *ctx;
5279 struct perf_event *event;
5281 mutex_lock(¤t->perf_event_mutex);
5282 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5283 ctx = perf_event_ctx_lock(event);
5284 perf_event_for_each_child(event, _perf_event_enable);
5285 perf_event_ctx_unlock(event, ctx);
5287 mutex_unlock(¤t->perf_event_mutex);
5292 int perf_event_task_disable(void)
5294 struct perf_event_context *ctx;
5295 struct perf_event *event;
5297 mutex_lock(¤t->perf_event_mutex);
5298 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5299 ctx = perf_event_ctx_lock(event);
5300 perf_event_for_each_child(event, _perf_event_disable);
5301 perf_event_ctx_unlock(event, ctx);
5303 mutex_unlock(¤t->perf_event_mutex);
5308 static int perf_event_index(struct perf_event *event)
5310 if (event->hw.state & PERF_HES_STOPPED)
5313 if (event->state != PERF_EVENT_STATE_ACTIVE)
5316 return event->pmu->event_idx(event);
5319 static void calc_timer_values(struct perf_event *event,
5326 *now = perf_clock();
5327 ctx_time = event->shadow_ctx_time + *now;
5328 __perf_update_times(event, ctx_time, enabled, running);
5331 static void perf_event_init_userpage(struct perf_event *event)
5333 struct perf_event_mmap_page *userpg;
5334 struct ring_buffer *rb;
5337 rb = rcu_dereference(event->rb);
5341 userpg = rb->user_page;
5343 /* Allow new userspace to detect that bit 0 is deprecated */
5344 userpg->cap_bit0_is_deprecated = 1;
5345 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5346 userpg->data_offset = PAGE_SIZE;
5347 userpg->data_size = perf_data_size(rb);
5353 void __weak arch_perf_update_userpage(
5354 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5359 * Callers need to ensure there can be no nesting of this function, otherwise
5360 * the seqlock logic goes bad. We can not serialize this because the arch
5361 * code calls this from NMI context.
5363 void perf_event_update_userpage(struct perf_event *event)
5365 struct perf_event_mmap_page *userpg;
5366 struct ring_buffer *rb;
5367 u64 enabled, running, now;
5370 rb = rcu_dereference(event->rb);
5375 * compute total_time_enabled, total_time_running
5376 * based on snapshot values taken when the event
5377 * was last scheduled in.
5379 * we cannot simply called update_context_time()
5380 * because of locking issue as we can be called in
5383 calc_timer_values(event, &now, &enabled, &running);
5385 userpg = rb->user_page;
5387 * Disable preemption to guarantee consistent time stamps are stored to
5393 userpg->index = perf_event_index(event);
5394 userpg->offset = perf_event_count(event);
5396 userpg->offset -= local64_read(&event->hw.prev_count);
5398 userpg->time_enabled = enabled +
5399 atomic64_read(&event->child_total_time_enabled);
5401 userpg->time_running = running +
5402 atomic64_read(&event->child_total_time_running);
5404 arch_perf_update_userpage(event, userpg, now);
5412 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5414 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5416 struct perf_event *event = vmf->vma->vm_file->private_data;
5417 struct ring_buffer *rb;
5418 vm_fault_t ret = VM_FAULT_SIGBUS;
5420 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5421 if (vmf->pgoff == 0)
5427 rb = rcu_dereference(event->rb);
5431 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5434 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5438 get_page(vmf->page);
5439 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5440 vmf->page->index = vmf->pgoff;
5449 static void ring_buffer_attach(struct perf_event *event,
5450 struct ring_buffer *rb)
5452 struct ring_buffer *old_rb = NULL;
5453 unsigned long flags;
5457 * Should be impossible, we set this when removing
5458 * event->rb_entry and wait/clear when adding event->rb_entry.
5460 WARN_ON_ONCE(event->rcu_pending);
5463 spin_lock_irqsave(&old_rb->event_lock, flags);
5464 list_del_rcu(&event->rb_entry);
5465 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5467 event->rcu_batches = get_state_synchronize_rcu();
5468 event->rcu_pending = 1;
5472 if (event->rcu_pending) {
5473 cond_synchronize_rcu(event->rcu_batches);
5474 event->rcu_pending = 0;
5477 spin_lock_irqsave(&rb->event_lock, flags);
5478 list_add_rcu(&event->rb_entry, &rb->event_list);
5479 spin_unlock_irqrestore(&rb->event_lock, flags);
5483 * Avoid racing with perf_mmap_close(AUX): stop the event
5484 * before swizzling the event::rb pointer; if it's getting
5485 * unmapped, its aux_mmap_count will be 0 and it won't
5486 * restart. See the comment in __perf_pmu_output_stop().
5488 * Data will inevitably be lost when set_output is done in
5489 * mid-air, but then again, whoever does it like this is
5490 * not in for the data anyway.
5493 perf_event_stop(event, 0);
5495 rcu_assign_pointer(event->rb, rb);
5498 ring_buffer_put(old_rb);
5500 * Since we detached before setting the new rb, so that we
5501 * could attach the new rb, we could have missed a wakeup.
5504 wake_up_all(&event->waitq);
5508 static void ring_buffer_wakeup(struct perf_event *event)
5510 struct ring_buffer *rb;
5513 rb = rcu_dereference(event->rb);
5515 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5516 wake_up_all(&event->waitq);
5521 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5523 struct ring_buffer *rb;
5526 rb = rcu_dereference(event->rb);
5528 if (!refcount_inc_not_zero(&rb->refcount))
5536 void ring_buffer_put(struct ring_buffer *rb)
5538 if (!refcount_dec_and_test(&rb->refcount))
5541 WARN_ON_ONCE(!list_empty(&rb->event_list));
5543 call_rcu(&rb->rcu_head, rb_free_rcu);
5546 static void perf_mmap_open(struct vm_area_struct *vma)
5548 struct perf_event *event = vma->vm_file->private_data;
5550 atomic_inc(&event->mmap_count);
5551 atomic_inc(&event->rb->mmap_count);
5554 atomic_inc(&event->rb->aux_mmap_count);
5556 if (event->pmu->event_mapped)
5557 event->pmu->event_mapped(event, vma->vm_mm);
5560 static void perf_pmu_output_stop(struct perf_event *event);
5563 * A buffer can be mmap()ed multiple times; either directly through the same
5564 * event, or through other events by use of perf_event_set_output().
5566 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5567 * the buffer here, where we still have a VM context. This means we need
5568 * to detach all events redirecting to us.
5570 static void perf_mmap_close(struct vm_area_struct *vma)
5572 struct perf_event *event = vma->vm_file->private_data;
5574 struct ring_buffer *rb = ring_buffer_get(event);
5575 struct user_struct *mmap_user = rb->mmap_user;
5576 int mmap_locked = rb->mmap_locked;
5577 unsigned long size = perf_data_size(rb);
5579 if (event->pmu->event_unmapped)
5580 event->pmu->event_unmapped(event, vma->vm_mm);
5583 * rb->aux_mmap_count will always drop before rb->mmap_count and
5584 * event->mmap_count, so it is ok to use event->mmap_mutex to
5585 * serialize with perf_mmap here.
5587 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5588 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5590 * Stop all AUX events that are writing to this buffer,
5591 * so that we can free its AUX pages and corresponding PMU
5592 * data. Note that after rb::aux_mmap_count dropped to zero,
5593 * they won't start any more (see perf_aux_output_begin()).
5595 perf_pmu_output_stop(event);
5597 /* now it's safe to free the pages */
5598 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5599 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5601 /* this has to be the last one */
5603 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5605 mutex_unlock(&event->mmap_mutex);
5608 atomic_dec(&rb->mmap_count);
5610 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5613 ring_buffer_attach(event, NULL);
5614 mutex_unlock(&event->mmap_mutex);
5616 /* If there's still other mmap()s of this buffer, we're done. */
5617 if (atomic_read(&rb->mmap_count))
5621 * No other mmap()s, detach from all other events that might redirect
5622 * into the now unreachable buffer. Somewhat complicated by the
5623 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5627 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5628 if (!atomic_long_inc_not_zero(&event->refcount)) {
5630 * This event is en-route to free_event() which will
5631 * detach it and remove it from the list.
5637 mutex_lock(&event->mmap_mutex);
5639 * Check we didn't race with perf_event_set_output() which can
5640 * swizzle the rb from under us while we were waiting to
5641 * acquire mmap_mutex.
5643 * If we find a different rb; ignore this event, a next
5644 * iteration will no longer find it on the list. We have to
5645 * still restart the iteration to make sure we're not now
5646 * iterating the wrong list.
5648 if (event->rb == rb)
5649 ring_buffer_attach(event, NULL);
5651 mutex_unlock(&event->mmap_mutex);
5655 * Restart the iteration; either we're on the wrong list or
5656 * destroyed its integrity by doing a deletion.
5663 * It could be there's still a few 0-ref events on the list; they'll
5664 * get cleaned up by free_event() -- they'll also still have their
5665 * ref on the rb and will free it whenever they are done with it.
5667 * Aside from that, this buffer is 'fully' detached and unmapped,
5668 * undo the VM accounting.
5671 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5672 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5673 free_uid(mmap_user);
5676 ring_buffer_put(rb); /* could be last */
5679 static const struct vm_operations_struct perf_mmap_vmops = {
5680 .open = perf_mmap_open,
5681 .close = perf_mmap_close, /* non mergeable */
5682 .fault = perf_mmap_fault,
5683 .page_mkwrite = perf_mmap_fault,
5686 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5688 struct perf_event *event = file->private_data;
5689 unsigned long user_locked, user_lock_limit;
5690 struct user_struct *user = current_user();
5691 unsigned long locked, lock_limit;
5692 struct ring_buffer *rb = NULL;
5693 unsigned long vma_size;
5694 unsigned long nr_pages;
5695 long user_extra = 0, extra = 0;
5696 int ret = 0, flags = 0;
5699 * Don't allow mmap() of inherited per-task counters. This would
5700 * create a performance issue due to all children writing to the
5703 if (event->cpu == -1 && event->attr.inherit)
5706 if (!(vma->vm_flags & VM_SHARED))
5709 vma_size = vma->vm_end - vma->vm_start;
5711 if (vma->vm_pgoff == 0) {
5712 nr_pages = (vma_size / PAGE_SIZE) - 1;
5715 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5716 * mapped, all subsequent mappings should have the same size
5717 * and offset. Must be above the normal perf buffer.
5719 u64 aux_offset, aux_size;
5724 nr_pages = vma_size / PAGE_SIZE;
5726 mutex_lock(&event->mmap_mutex);
5733 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5734 aux_size = READ_ONCE(rb->user_page->aux_size);
5736 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5739 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5742 /* already mapped with a different offset */
5743 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5746 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5749 /* already mapped with a different size */
5750 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5753 if (!is_power_of_2(nr_pages))
5756 if (!atomic_inc_not_zero(&rb->mmap_count))
5759 if (rb_has_aux(rb)) {
5760 atomic_inc(&rb->aux_mmap_count);
5765 atomic_set(&rb->aux_mmap_count, 1);
5766 user_extra = nr_pages;
5772 * If we have rb pages ensure they're a power-of-two number, so we
5773 * can do bitmasks instead of modulo.
5775 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5778 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5781 WARN_ON_ONCE(event->ctx->parent_ctx);
5783 mutex_lock(&event->mmap_mutex);
5785 if (event->rb->nr_pages != nr_pages) {
5790 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5792 * Raced against perf_mmap_close() through
5793 * perf_event_set_output(). Try again, hope for better
5796 mutex_unlock(&event->mmap_mutex);
5803 user_extra = nr_pages + 1;
5806 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5809 * Increase the limit linearly with more CPUs:
5811 user_lock_limit *= num_online_cpus();
5813 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5815 if (user_locked > user_lock_limit)
5816 extra = user_locked - user_lock_limit;
5818 lock_limit = rlimit(RLIMIT_MEMLOCK);
5819 lock_limit >>= PAGE_SHIFT;
5820 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5822 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5823 !capable(CAP_IPC_LOCK)) {
5828 WARN_ON(!rb && event->rb);
5830 if (vma->vm_flags & VM_WRITE)
5831 flags |= RING_BUFFER_WRITABLE;
5834 rb = rb_alloc(nr_pages,
5835 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5843 atomic_set(&rb->mmap_count, 1);
5844 rb->mmap_user = get_current_user();
5845 rb->mmap_locked = extra;
5847 ring_buffer_attach(event, rb);
5849 perf_event_init_userpage(event);
5850 perf_event_update_userpage(event);
5852 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5853 event->attr.aux_watermark, flags);
5855 rb->aux_mmap_locked = extra;
5860 atomic_long_add(user_extra, &user->locked_vm);
5861 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5863 atomic_inc(&event->mmap_count);
5865 atomic_dec(&rb->mmap_count);
5868 mutex_unlock(&event->mmap_mutex);
5871 * Since pinned accounting is per vm we cannot allow fork() to copy our
5874 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5875 vma->vm_ops = &perf_mmap_vmops;
5877 if (event->pmu->event_mapped)
5878 event->pmu->event_mapped(event, vma->vm_mm);
5883 static int perf_fasync(int fd, struct file *filp, int on)
5885 struct inode *inode = file_inode(filp);
5886 struct perf_event *event = filp->private_data;
5890 retval = fasync_helper(fd, filp, on, &event->fasync);
5891 inode_unlock(inode);
5899 static const struct file_operations perf_fops = {
5900 .llseek = no_llseek,
5901 .release = perf_release,
5904 .unlocked_ioctl = perf_ioctl,
5905 .compat_ioctl = perf_compat_ioctl,
5907 .fasync = perf_fasync,
5913 * If there's data, ensure we set the poll() state and publish everything
5914 * to user-space before waking everybody up.
5917 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5919 /* only the parent has fasync state */
5921 event = event->parent;
5922 return &event->fasync;
5925 void perf_event_wakeup(struct perf_event *event)
5927 ring_buffer_wakeup(event);
5929 if (event->pending_kill) {
5930 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5931 event->pending_kill = 0;
5935 static void perf_pending_event_disable(struct perf_event *event)
5937 int cpu = READ_ONCE(event->pending_disable);
5942 if (cpu == smp_processor_id()) {
5943 WRITE_ONCE(event->pending_disable, -1);
5944 perf_event_disable_local(event);
5951 * perf_event_disable_inatomic()
5952 * @pending_disable = CPU-A;
5956 * @pending_disable = -1;
5959 * perf_event_disable_inatomic()
5960 * @pending_disable = CPU-B;
5961 * irq_work_queue(); // FAILS
5964 * perf_pending_event()
5966 * But the event runs on CPU-B and wants disabling there.
5968 irq_work_queue_on(&event->pending, cpu);
5971 static void perf_pending_event(struct irq_work *entry)
5973 struct perf_event *event = container_of(entry, struct perf_event, pending);
5976 rctx = perf_swevent_get_recursion_context();
5978 * If we 'fail' here, that's OK, it means recursion is already disabled
5979 * and we won't recurse 'further'.
5982 perf_pending_event_disable(event);
5984 if (event->pending_wakeup) {
5985 event->pending_wakeup = 0;
5986 perf_event_wakeup(event);
5990 perf_swevent_put_recursion_context(rctx);
5994 * We assume there is only KVM supporting the callbacks.
5995 * Later on, we might change it to a list if there is
5996 * another virtualization implementation supporting the callbacks.
5998 struct perf_guest_info_callbacks *perf_guest_cbs;
6000 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6002 perf_guest_cbs = cbs;
6005 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6007 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6009 perf_guest_cbs = NULL;
6012 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6015 perf_output_sample_regs(struct perf_output_handle *handle,
6016 struct pt_regs *regs, u64 mask)
6019 DECLARE_BITMAP(_mask, 64);
6021 bitmap_from_u64(_mask, mask);
6022 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6025 val = perf_reg_value(regs, bit);
6026 perf_output_put(handle, val);
6030 static void perf_sample_regs_user(struct perf_regs *regs_user,
6031 struct pt_regs *regs,
6032 struct pt_regs *regs_user_copy)
6034 if (user_mode(regs)) {
6035 regs_user->abi = perf_reg_abi(current);
6036 regs_user->regs = regs;
6037 } else if (!(current->flags & PF_KTHREAD)) {
6038 perf_get_regs_user(regs_user, regs, regs_user_copy);
6040 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6041 regs_user->regs = NULL;
6045 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6046 struct pt_regs *regs)
6048 regs_intr->regs = regs;
6049 regs_intr->abi = perf_reg_abi(current);
6054 * Get remaining task size from user stack pointer.
6056 * It'd be better to take stack vma map and limit this more
6057 * precisely, but there's no way to get it safely under interrupt,
6058 * so using TASK_SIZE as limit.
6060 static u64 perf_ustack_task_size(struct pt_regs *regs)
6062 unsigned long addr = perf_user_stack_pointer(regs);
6064 if (!addr || addr >= TASK_SIZE)
6067 return TASK_SIZE - addr;
6071 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6072 struct pt_regs *regs)
6076 /* No regs, no stack pointer, no dump. */
6081 * Check if we fit in with the requested stack size into the:
6083 * If we don't, we limit the size to the TASK_SIZE.
6085 * - remaining sample size
6086 * If we don't, we customize the stack size to
6087 * fit in to the remaining sample size.
6090 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6091 stack_size = min(stack_size, (u16) task_size);
6093 /* Current header size plus static size and dynamic size. */
6094 header_size += 2 * sizeof(u64);
6096 /* Do we fit in with the current stack dump size? */
6097 if ((u16) (header_size + stack_size) < header_size) {
6099 * If we overflow the maximum size for the sample,
6100 * we customize the stack dump size to fit in.
6102 stack_size = USHRT_MAX - header_size - sizeof(u64);
6103 stack_size = round_up(stack_size, sizeof(u64));
6110 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6111 struct pt_regs *regs)
6113 /* Case of a kernel thread, nothing to dump */
6116 perf_output_put(handle, size);
6126 * - the size requested by user or the best one we can fit
6127 * in to the sample max size
6129 * - user stack dump data
6131 * - the actual dumped size
6135 perf_output_put(handle, dump_size);
6138 sp = perf_user_stack_pointer(regs);
6141 rem = __output_copy_user(handle, (void *) sp, dump_size);
6143 dyn_size = dump_size - rem;
6145 perf_output_skip(handle, rem);
6148 perf_output_put(handle, dyn_size);
6152 static void __perf_event_header__init_id(struct perf_event_header *header,
6153 struct perf_sample_data *data,
6154 struct perf_event *event)
6156 u64 sample_type = event->attr.sample_type;
6158 data->type = sample_type;
6159 header->size += event->id_header_size;
6161 if (sample_type & PERF_SAMPLE_TID) {
6162 /* namespace issues */
6163 data->tid_entry.pid = perf_event_pid(event, current);
6164 data->tid_entry.tid = perf_event_tid(event, current);
6167 if (sample_type & PERF_SAMPLE_TIME)
6168 data->time = perf_event_clock(event);
6170 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6171 data->id = primary_event_id(event);
6173 if (sample_type & PERF_SAMPLE_STREAM_ID)
6174 data->stream_id = event->id;
6176 if (sample_type & PERF_SAMPLE_CPU) {
6177 data->cpu_entry.cpu = raw_smp_processor_id();
6178 data->cpu_entry.reserved = 0;
6182 void perf_event_header__init_id(struct perf_event_header *header,
6183 struct perf_sample_data *data,
6184 struct perf_event *event)
6186 if (event->attr.sample_id_all)
6187 __perf_event_header__init_id(header, data, event);
6190 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6191 struct perf_sample_data *data)
6193 u64 sample_type = data->type;
6195 if (sample_type & PERF_SAMPLE_TID)
6196 perf_output_put(handle, data->tid_entry);
6198 if (sample_type & PERF_SAMPLE_TIME)
6199 perf_output_put(handle, data->time);
6201 if (sample_type & PERF_SAMPLE_ID)
6202 perf_output_put(handle, data->id);
6204 if (sample_type & PERF_SAMPLE_STREAM_ID)
6205 perf_output_put(handle, data->stream_id);
6207 if (sample_type & PERF_SAMPLE_CPU)
6208 perf_output_put(handle, data->cpu_entry);
6210 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6211 perf_output_put(handle, data->id);
6214 void perf_event__output_id_sample(struct perf_event *event,
6215 struct perf_output_handle *handle,
6216 struct perf_sample_data *sample)
6218 if (event->attr.sample_id_all)
6219 __perf_event__output_id_sample(handle, sample);
6222 static void perf_output_read_one(struct perf_output_handle *handle,
6223 struct perf_event *event,
6224 u64 enabled, u64 running)
6226 u64 read_format = event->attr.read_format;
6230 values[n++] = perf_event_count(event);
6231 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6232 values[n++] = enabled +
6233 atomic64_read(&event->child_total_time_enabled);
6235 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6236 values[n++] = running +
6237 atomic64_read(&event->child_total_time_running);
6239 if (read_format & PERF_FORMAT_ID)
6240 values[n++] = primary_event_id(event);
6242 __output_copy(handle, values, n * sizeof(u64));
6245 static void perf_output_read_group(struct perf_output_handle *handle,
6246 struct perf_event *event,
6247 u64 enabled, u64 running)
6249 struct perf_event *leader = event->group_leader, *sub;
6250 u64 read_format = event->attr.read_format;
6254 values[n++] = 1 + leader->nr_siblings;
6256 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6257 values[n++] = enabled;
6259 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6260 values[n++] = running;
6262 if ((leader != event) &&
6263 (leader->state == PERF_EVENT_STATE_ACTIVE))
6264 leader->pmu->read(leader);
6266 values[n++] = perf_event_count(leader);
6267 if (read_format & PERF_FORMAT_ID)
6268 values[n++] = primary_event_id(leader);
6270 __output_copy(handle, values, n * sizeof(u64));
6272 for_each_sibling_event(sub, leader) {
6275 if ((sub != event) &&
6276 (sub->state == PERF_EVENT_STATE_ACTIVE))
6277 sub->pmu->read(sub);
6279 values[n++] = perf_event_count(sub);
6280 if (read_format & PERF_FORMAT_ID)
6281 values[n++] = primary_event_id(sub);
6283 __output_copy(handle, values, n * sizeof(u64));
6287 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6288 PERF_FORMAT_TOTAL_TIME_RUNNING)
6291 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6293 * The problem is that its both hard and excessively expensive to iterate the
6294 * child list, not to mention that its impossible to IPI the children running
6295 * on another CPU, from interrupt/NMI context.
6297 static void perf_output_read(struct perf_output_handle *handle,
6298 struct perf_event *event)
6300 u64 enabled = 0, running = 0, now;
6301 u64 read_format = event->attr.read_format;
6304 * compute total_time_enabled, total_time_running
6305 * based on snapshot values taken when the event
6306 * was last scheduled in.
6308 * we cannot simply called update_context_time()
6309 * because of locking issue as we are called in
6312 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6313 calc_timer_values(event, &now, &enabled, &running);
6315 if (event->attr.read_format & PERF_FORMAT_GROUP)
6316 perf_output_read_group(handle, event, enabled, running);
6318 perf_output_read_one(handle, event, enabled, running);
6321 void perf_output_sample(struct perf_output_handle *handle,
6322 struct perf_event_header *header,
6323 struct perf_sample_data *data,
6324 struct perf_event *event)
6326 u64 sample_type = data->type;
6328 perf_output_put(handle, *header);
6330 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6331 perf_output_put(handle, data->id);
6333 if (sample_type & PERF_SAMPLE_IP)
6334 perf_output_put(handle, data->ip);
6336 if (sample_type & PERF_SAMPLE_TID)
6337 perf_output_put(handle, data->tid_entry);
6339 if (sample_type & PERF_SAMPLE_TIME)
6340 perf_output_put(handle, data->time);
6342 if (sample_type & PERF_SAMPLE_ADDR)
6343 perf_output_put(handle, data->addr);
6345 if (sample_type & PERF_SAMPLE_ID)
6346 perf_output_put(handle, data->id);
6348 if (sample_type & PERF_SAMPLE_STREAM_ID)
6349 perf_output_put(handle, data->stream_id);
6351 if (sample_type & PERF_SAMPLE_CPU)
6352 perf_output_put(handle, data->cpu_entry);
6354 if (sample_type & PERF_SAMPLE_PERIOD)
6355 perf_output_put(handle, data->period);
6357 if (sample_type & PERF_SAMPLE_READ)
6358 perf_output_read(handle, event);
6360 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6363 size += data->callchain->nr;
6364 size *= sizeof(u64);
6365 __output_copy(handle, data->callchain, size);
6368 if (sample_type & PERF_SAMPLE_RAW) {
6369 struct perf_raw_record *raw = data->raw;
6372 struct perf_raw_frag *frag = &raw->frag;
6374 perf_output_put(handle, raw->size);
6377 __output_custom(handle, frag->copy,
6378 frag->data, frag->size);
6380 __output_copy(handle, frag->data,
6383 if (perf_raw_frag_last(frag))
6388 __output_skip(handle, NULL, frag->pad);
6394 .size = sizeof(u32),
6397 perf_output_put(handle, raw);
6401 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6402 if (data->br_stack) {
6405 size = data->br_stack->nr
6406 * sizeof(struct perf_branch_entry);
6408 perf_output_put(handle, data->br_stack->nr);
6409 perf_output_copy(handle, data->br_stack->entries, size);
6412 * we always store at least the value of nr
6415 perf_output_put(handle, nr);
6419 if (sample_type & PERF_SAMPLE_REGS_USER) {
6420 u64 abi = data->regs_user.abi;
6423 * If there are no regs to dump, notice it through
6424 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6426 perf_output_put(handle, abi);
6429 u64 mask = event->attr.sample_regs_user;
6430 perf_output_sample_regs(handle,
6431 data->regs_user.regs,
6436 if (sample_type & PERF_SAMPLE_STACK_USER) {
6437 perf_output_sample_ustack(handle,
6438 data->stack_user_size,
6439 data->regs_user.regs);
6442 if (sample_type & PERF_SAMPLE_WEIGHT)
6443 perf_output_put(handle, data->weight);
6445 if (sample_type & PERF_SAMPLE_DATA_SRC)
6446 perf_output_put(handle, data->data_src.val);
6448 if (sample_type & PERF_SAMPLE_TRANSACTION)
6449 perf_output_put(handle, data->txn);
6451 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6452 u64 abi = data->regs_intr.abi;
6454 * If there are no regs to dump, notice it through
6455 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6457 perf_output_put(handle, abi);
6460 u64 mask = event->attr.sample_regs_intr;
6462 perf_output_sample_regs(handle,
6463 data->regs_intr.regs,
6468 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6469 perf_output_put(handle, data->phys_addr);
6471 if (!event->attr.watermark) {
6472 int wakeup_events = event->attr.wakeup_events;
6474 if (wakeup_events) {
6475 struct ring_buffer *rb = handle->rb;
6476 int events = local_inc_return(&rb->events);
6478 if (events >= wakeup_events) {
6479 local_sub(wakeup_events, &rb->events);
6480 local_inc(&rb->wakeup);
6486 static u64 perf_virt_to_phys(u64 virt)
6489 struct page *p = NULL;
6494 if (virt >= TASK_SIZE) {
6495 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6496 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6497 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6498 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6501 * Walking the pages tables for user address.
6502 * Interrupts are disabled, so it prevents any tear down
6503 * of the page tables.
6504 * Try IRQ-safe __get_user_pages_fast first.
6505 * If failed, leave phys_addr as 0.
6507 if ((current->mm != NULL) &&
6508 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6509 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6518 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6520 struct perf_callchain_entry *
6521 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6523 bool kernel = !event->attr.exclude_callchain_kernel;
6524 bool user = !event->attr.exclude_callchain_user;
6525 /* Disallow cross-task user callchains. */
6526 bool crosstask = event->ctx->task && event->ctx->task != current;
6527 const u32 max_stack = event->attr.sample_max_stack;
6528 struct perf_callchain_entry *callchain;
6530 if (!kernel && !user)
6531 return &__empty_callchain;
6533 callchain = get_perf_callchain(regs, 0, kernel, user,
6534 max_stack, crosstask, true);
6535 return callchain ?: &__empty_callchain;
6538 void perf_prepare_sample(struct perf_event_header *header,
6539 struct perf_sample_data *data,
6540 struct perf_event *event,
6541 struct pt_regs *regs)
6543 u64 sample_type = event->attr.sample_type;
6545 header->type = PERF_RECORD_SAMPLE;
6546 header->size = sizeof(*header) + event->header_size;
6549 header->misc |= perf_misc_flags(regs);
6551 __perf_event_header__init_id(header, data, event);
6553 if (sample_type & PERF_SAMPLE_IP)
6554 data->ip = perf_instruction_pointer(regs);
6556 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6559 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6560 data->callchain = perf_callchain(event, regs);
6562 size += data->callchain->nr;
6564 header->size += size * sizeof(u64);
6567 if (sample_type & PERF_SAMPLE_RAW) {
6568 struct perf_raw_record *raw = data->raw;
6572 struct perf_raw_frag *frag = &raw->frag;
6577 if (perf_raw_frag_last(frag))
6582 size = round_up(sum + sizeof(u32), sizeof(u64));
6583 raw->size = size - sizeof(u32);
6584 frag->pad = raw->size - sum;
6589 header->size += size;
6592 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6593 int size = sizeof(u64); /* nr */
6594 if (data->br_stack) {
6595 size += data->br_stack->nr
6596 * sizeof(struct perf_branch_entry);
6598 header->size += size;
6601 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6602 perf_sample_regs_user(&data->regs_user, regs,
6603 &data->regs_user_copy);
6605 if (sample_type & PERF_SAMPLE_REGS_USER) {
6606 /* regs dump ABI info */
6607 int size = sizeof(u64);
6609 if (data->regs_user.regs) {
6610 u64 mask = event->attr.sample_regs_user;
6611 size += hweight64(mask) * sizeof(u64);
6614 header->size += size;
6617 if (sample_type & PERF_SAMPLE_STACK_USER) {
6619 * Either we need PERF_SAMPLE_STACK_USER bit to be always
6620 * processed as the last one or have additional check added
6621 * in case new sample type is added, because we could eat
6622 * up the rest of the sample size.
6624 u16 stack_size = event->attr.sample_stack_user;
6625 u16 size = sizeof(u64);
6627 stack_size = perf_sample_ustack_size(stack_size, header->size,
6628 data->regs_user.regs);
6631 * If there is something to dump, add space for the dump
6632 * itself and for the field that tells the dynamic size,
6633 * which is how many have been actually dumped.
6636 size += sizeof(u64) + stack_size;
6638 data->stack_user_size = stack_size;
6639 header->size += size;
6642 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6643 /* regs dump ABI info */
6644 int size = sizeof(u64);
6646 perf_sample_regs_intr(&data->regs_intr, regs);
6648 if (data->regs_intr.regs) {
6649 u64 mask = event->attr.sample_regs_intr;
6651 size += hweight64(mask) * sizeof(u64);
6654 header->size += size;
6657 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6658 data->phys_addr = perf_virt_to_phys(data->addr);
6661 static __always_inline int
6662 __perf_event_output(struct perf_event *event,
6663 struct perf_sample_data *data,
6664 struct pt_regs *regs,
6665 int (*output_begin)(struct perf_output_handle *,
6666 struct perf_event *,
6669 struct perf_output_handle handle;
6670 struct perf_event_header header;
6673 /* protect the callchain buffers */
6676 perf_prepare_sample(&header, data, event, regs);
6678 err = output_begin(&handle, event, header.size);
6682 perf_output_sample(&handle, &header, data, event);
6684 perf_output_end(&handle);
6692 perf_event_output_forward(struct perf_event *event,
6693 struct perf_sample_data *data,
6694 struct pt_regs *regs)
6696 __perf_event_output(event, data, regs, perf_output_begin_forward);
6700 perf_event_output_backward(struct perf_event *event,
6701 struct perf_sample_data *data,
6702 struct pt_regs *regs)
6704 __perf_event_output(event, data, regs, perf_output_begin_backward);
6708 perf_event_output(struct perf_event *event,
6709 struct perf_sample_data *data,
6710 struct pt_regs *regs)
6712 return __perf_event_output(event, data, regs, perf_output_begin);
6719 struct perf_read_event {
6720 struct perf_event_header header;
6727 perf_event_read_event(struct perf_event *event,
6728 struct task_struct *task)
6730 struct perf_output_handle handle;
6731 struct perf_sample_data sample;
6732 struct perf_read_event read_event = {
6734 .type = PERF_RECORD_READ,
6736 .size = sizeof(read_event) + event->read_size,
6738 .pid = perf_event_pid(event, task),
6739 .tid = perf_event_tid(event, task),
6743 perf_event_header__init_id(&read_event.header, &sample, event);
6744 ret = perf_output_begin(&handle, event, read_event.header.size);
6748 perf_output_put(&handle, read_event);
6749 perf_output_read(&handle, event);
6750 perf_event__output_id_sample(event, &handle, &sample);
6752 perf_output_end(&handle);
6755 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6758 perf_iterate_ctx(struct perf_event_context *ctx,
6759 perf_iterate_f output,
6760 void *data, bool all)
6762 struct perf_event *event;
6764 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6766 if (event->state < PERF_EVENT_STATE_INACTIVE)
6768 if (!event_filter_match(event))
6772 output(event, data);
6776 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6778 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6779 struct perf_event *event;
6781 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6783 * Skip events that are not fully formed yet; ensure that
6784 * if we observe event->ctx, both event and ctx will be
6785 * complete enough. See perf_install_in_context().
6787 if (!smp_load_acquire(&event->ctx))
6790 if (event->state < PERF_EVENT_STATE_INACTIVE)
6792 if (!event_filter_match(event))
6794 output(event, data);
6799 * Iterate all events that need to receive side-band events.
6801 * For new callers; ensure that account_pmu_sb_event() includes
6802 * your event, otherwise it might not get delivered.
6805 perf_iterate_sb(perf_iterate_f output, void *data,
6806 struct perf_event_context *task_ctx)
6808 struct perf_event_context *ctx;
6815 * If we have task_ctx != NULL we only notify the task context itself.
6816 * The task_ctx is set only for EXIT events before releasing task
6820 perf_iterate_ctx(task_ctx, output, data, false);
6824 perf_iterate_sb_cpu(output, data);
6826 for_each_task_context_nr(ctxn) {
6827 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6829 perf_iterate_ctx(ctx, output, data, false);
6837 * Clear all file-based filters at exec, they'll have to be
6838 * re-instated when/if these objects are mmapped again.
6840 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6842 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6843 struct perf_addr_filter *filter;
6844 unsigned int restart = 0, count = 0;
6845 unsigned long flags;
6847 if (!has_addr_filter(event))
6850 raw_spin_lock_irqsave(&ifh->lock, flags);
6851 list_for_each_entry(filter, &ifh->list, entry) {
6852 if (filter->path.dentry) {
6853 event->addr_filter_ranges[count].start = 0;
6854 event->addr_filter_ranges[count].size = 0;
6862 event->addr_filters_gen++;
6863 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6866 perf_event_stop(event, 1);
6869 void perf_event_exec(void)
6871 struct perf_event_context *ctx;
6875 for_each_task_context_nr(ctxn) {
6876 ctx = current->perf_event_ctxp[ctxn];
6880 perf_event_enable_on_exec(ctxn);
6882 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6888 struct remote_output {
6889 struct ring_buffer *rb;
6893 static void __perf_event_output_stop(struct perf_event *event, void *data)
6895 struct perf_event *parent = event->parent;
6896 struct remote_output *ro = data;
6897 struct ring_buffer *rb = ro->rb;
6898 struct stop_event_data sd = {
6902 if (!has_aux(event))
6909 * In case of inheritance, it will be the parent that links to the
6910 * ring-buffer, but it will be the child that's actually using it.
6912 * We are using event::rb to determine if the event should be stopped,
6913 * however this may race with ring_buffer_attach() (through set_output),
6914 * which will make us skip the event that actually needs to be stopped.
6915 * So ring_buffer_attach() has to stop an aux event before re-assigning
6918 if (rcu_dereference(parent->rb) == rb)
6919 ro->err = __perf_event_stop(&sd);
6922 static int __perf_pmu_output_stop(void *info)
6924 struct perf_event *event = info;
6925 struct pmu *pmu = event->pmu;
6926 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6927 struct remote_output ro = {
6932 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6933 if (cpuctx->task_ctx)
6934 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6941 static void perf_pmu_output_stop(struct perf_event *event)
6943 struct perf_event *iter;
6948 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6950 * For per-CPU events, we need to make sure that neither they
6951 * nor their children are running; for cpu==-1 events it's
6952 * sufficient to stop the event itself if it's active, since
6953 * it can't have children.
6957 cpu = READ_ONCE(iter->oncpu);
6962 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6963 if (err == -EAGAIN) {
6972 * task tracking -- fork/exit
6974 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6977 struct perf_task_event {
6978 struct task_struct *task;
6979 struct perf_event_context *task_ctx;
6982 struct perf_event_header header;
6992 static int perf_event_task_match(struct perf_event *event)
6994 return event->attr.comm || event->attr.mmap ||
6995 event->attr.mmap2 || event->attr.mmap_data ||
6999 static void perf_event_task_output(struct perf_event *event,
7002 struct perf_task_event *task_event = data;
7003 struct perf_output_handle handle;
7004 struct perf_sample_data sample;
7005 struct task_struct *task = task_event->task;
7006 int ret, size = task_event->event_id.header.size;
7008 if (!perf_event_task_match(event))
7011 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7013 ret = perf_output_begin(&handle, event,
7014 task_event->event_id.header.size);
7018 task_event->event_id.pid = perf_event_pid(event, task);
7019 task_event->event_id.ppid = perf_event_pid(event, current);
7021 task_event->event_id.tid = perf_event_tid(event, task);
7022 task_event->event_id.ptid = perf_event_tid(event, current);
7024 task_event->event_id.time = perf_event_clock(event);
7026 perf_output_put(&handle, task_event->event_id);
7028 perf_event__output_id_sample(event, &handle, &sample);
7030 perf_output_end(&handle);
7032 task_event->event_id.header.size = size;
7035 static void perf_event_task(struct task_struct *task,
7036 struct perf_event_context *task_ctx,
7039 struct perf_task_event task_event;
7041 if (!atomic_read(&nr_comm_events) &&
7042 !atomic_read(&nr_mmap_events) &&
7043 !atomic_read(&nr_task_events))
7046 task_event = (struct perf_task_event){
7048 .task_ctx = task_ctx,
7051 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7053 .size = sizeof(task_event.event_id),
7063 perf_iterate_sb(perf_event_task_output,
7068 void perf_event_fork(struct task_struct *task)
7070 perf_event_task(task, NULL, 1);
7071 perf_event_namespaces(task);
7078 struct perf_comm_event {
7079 struct task_struct *task;
7084 struct perf_event_header header;
7091 static int perf_event_comm_match(struct perf_event *event)
7093 return event->attr.comm;
7096 static void perf_event_comm_output(struct perf_event *event,
7099 struct perf_comm_event *comm_event = data;
7100 struct perf_output_handle handle;
7101 struct perf_sample_data sample;
7102 int size = comm_event->event_id.header.size;
7105 if (!perf_event_comm_match(event))
7108 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7109 ret = perf_output_begin(&handle, event,
7110 comm_event->event_id.header.size);
7115 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7116 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7118 perf_output_put(&handle, comm_event->event_id);
7119 __output_copy(&handle, comm_event->comm,
7120 comm_event->comm_size);
7122 perf_event__output_id_sample(event, &handle, &sample);
7124 perf_output_end(&handle);
7126 comm_event->event_id.header.size = size;
7129 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7131 char comm[TASK_COMM_LEN];
7134 memset(comm, 0, sizeof(comm));
7135 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7136 size = ALIGN(strlen(comm)+1, sizeof(u64));
7138 comm_event->comm = comm;
7139 comm_event->comm_size = size;
7141 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7143 perf_iterate_sb(perf_event_comm_output,
7148 void perf_event_comm(struct task_struct *task, bool exec)
7150 struct perf_comm_event comm_event;
7152 if (!atomic_read(&nr_comm_events))
7155 comm_event = (struct perf_comm_event){
7161 .type = PERF_RECORD_COMM,
7162 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7170 perf_event_comm_event(&comm_event);
7174 * namespaces tracking
7177 struct perf_namespaces_event {
7178 struct task_struct *task;
7181 struct perf_event_header header;
7186 struct perf_ns_link_info link_info[NR_NAMESPACES];
7190 static int perf_event_namespaces_match(struct perf_event *event)
7192 return event->attr.namespaces;
7195 static void perf_event_namespaces_output(struct perf_event *event,
7198 struct perf_namespaces_event *namespaces_event = data;
7199 struct perf_output_handle handle;
7200 struct perf_sample_data sample;
7201 u16 header_size = namespaces_event->event_id.header.size;
7204 if (!perf_event_namespaces_match(event))
7207 perf_event_header__init_id(&namespaces_event->event_id.header,
7209 ret = perf_output_begin(&handle, event,
7210 namespaces_event->event_id.header.size);
7214 namespaces_event->event_id.pid = perf_event_pid(event,
7215 namespaces_event->task);
7216 namespaces_event->event_id.tid = perf_event_tid(event,
7217 namespaces_event->task);
7219 perf_output_put(&handle, namespaces_event->event_id);
7221 perf_event__output_id_sample(event, &handle, &sample);
7223 perf_output_end(&handle);
7225 namespaces_event->event_id.header.size = header_size;
7228 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7229 struct task_struct *task,
7230 const struct proc_ns_operations *ns_ops)
7232 struct path ns_path;
7233 struct inode *ns_inode;
7236 error = ns_get_path(&ns_path, task, ns_ops);
7238 ns_inode = ns_path.dentry->d_inode;
7239 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7240 ns_link_info->ino = ns_inode->i_ino;
7245 void perf_event_namespaces(struct task_struct *task)
7247 struct perf_namespaces_event namespaces_event;
7248 struct perf_ns_link_info *ns_link_info;
7250 if (!atomic_read(&nr_namespaces_events))
7253 namespaces_event = (struct perf_namespaces_event){
7257 .type = PERF_RECORD_NAMESPACES,
7259 .size = sizeof(namespaces_event.event_id),
7263 .nr_namespaces = NR_NAMESPACES,
7264 /* .link_info[NR_NAMESPACES] */
7268 ns_link_info = namespaces_event.event_id.link_info;
7270 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7271 task, &mntns_operations);
7273 #ifdef CONFIG_USER_NS
7274 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7275 task, &userns_operations);
7277 #ifdef CONFIG_NET_NS
7278 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7279 task, &netns_operations);
7281 #ifdef CONFIG_UTS_NS
7282 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7283 task, &utsns_operations);
7285 #ifdef CONFIG_IPC_NS
7286 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7287 task, &ipcns_operations);
7289 #ifdef CONFIG_PID_NS
7290 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7291 task, &pidns_operations);
7293 #ifdef CONFIG_CGROUPS
7294 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7295 task, &cgroupns_operations);
7298 perf_iterate_sb(perf_event_namespaces_output,
7307 struct perf_mmap_event {
7308 struct vm_area_struct *vma;
7310 const char *file_name;
7318 struct perf_event_header header;
7328 static int perf_event_mmap_match(struct perf_event *event,
7331 struct perf_mmap_event *mmap_event = data;
7332 struct vm_area_struct *vma = mmap_event->vma;
7333 int executable = vma->vm_flags & VM_EXEC;
7335 return (!executable && event->attr.mmap_data) ||
7336 (executable && (event->attr.mmap || event->attr.mmap2));
7339 static void perf_event_mmap_output(struct perf_event *event,
7342 struct perf_mmap_event *mmap_event = data;
7343 struct perf_output_handle handle;
7344 struct perf_sample_data sample;
7345 int size = mmap_event->event_id.header.size;
7346 u32 type = mmap_event->event_id.header.type;
7349 if (!perf_event_mmap_match(event, data))
7352 if (event->attr.mmap2) {
7353 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7354 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7355 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7356 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7357 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7358 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7359 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7362 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7363 ret = perf_output_begin(&handle, event,
7364 mmap_event->event_id.header.size);
7368 mmap_event->event_id.pid = perf_event_pid(event, current);
7369 mmap_event->event_id.tid = perf_event_tid(event, current);
7371 perf_output_put(&handle, mmap_event->event_id);
7373 if (event->attr.mmap2) {
7374 perf_output_put(&handle, mmap_event->maj);
7375 perf_output_put(&handle, mmap_event->min);
7376 perf_output_put(&handle, mmap_event->ino);
7377 perf_output_put(&handle, mmap_event->ino_generation);
7378 perf_output_put(&handle, mmap_event->prot);
7379 perf_output_put(&handle, mmap_event->flags);
7382 __output_copy(&handle, mmap_event->file_name,
7383 mmap_event->file_size);
7385 perf_event__output_id_sample(event, &handle, &sample);
7387 perf_output_end(&handle);
7389 mmap_event->event_id.header.size = size;
7390 mmap_event->event_id.header.type = type;
7393 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7395 struct vm_area_struct *vma = mmap_event->vma;
7396 struct file *file = vma->vm_file;
7397 int maj = 0, min = 0;
7398 u64 ino = 0, gen = 0;
7399 u32 prot = 0, flags = 0;
7405 if (vma->vm_flags & VM_READ)
7407 if (vma->vm_flags & VM_WRITE)
7409 if (vma->vm_flags & VM_EXEC)
7412 if (vma->vm_flags & VM_MAYSHARE)
7415 flags = MAP_PRIVATE;
7417 if (vma->vm_flags & VM_DENYWRITE)
7418 flags |= MAP_DENYWRITE;
7419 if (vma->vm_flags & VM_MAYEXEC)
7420 flags |= MAP_EXECUTABLE;
7421 if (vma->vm_flags & VM_LOCKED)
7422 flags |= MAP_LOCKED;
7423 if (vma->vm_flags & VM_HUGETLB)
7424 flags |= MAP_HUGETLB;
7427 struct inode *inode;
7430 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7436 * d_path() works from the end of the rb backwards, so we
7437 * need to add enough zero bytes after the string to handle
7438 * the 64bit alignment we do later.
7440 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7445 inode = file_inode(vma->vm_file);
7446 dev = inode->i_sb->s_dev;
7448 gen = inode->i_generation;
7454 if (vma->vm_ops && vma->vm_ops->name) {
7455 name = (char *) vma->vm_ops->name(vma);
7460 name = (char *)arch_vma_name(vma);
7464 if (vma->vm_start <= vma->vm_mm->start_brk &&
7465 vma->vm_end >= vma->vm_mm->brk) {
7469 if (vma->vm_start <= vma->vm_mm->start_stack &&
7470 vma->vm_end >= vma->vm_mm->start_stack) {
7480 strlcpy(tmp, name, sizeof(tmp));
7484 * Since our buffer works in 8 byte units we need to align our string
7485 * size to a multiple of 8. However, we must guarantee the tail end is
7486 * zero'd out to avoid leaking random bits to userspace.
7488 size = strlen(name)+1;
7489 while (!IS_ALIGNED(size, sizeof(u64)))
7490 name[size++] = '\0';
7492 mmap_event->file_name = name;
7493 mmap_event->file_size = size;
7494 mmap_event->maj = maj;
7495 mmap_event->min = min;
7496 mmap_event->ino = ino;
7497 mmap_event->ino_generation = gen;
7498 mmap_event->prot = prot;
7499 mmap_event->flags = flags;
7501 if (!(vma->vm_flags & VM_EXEC))
7502 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7504 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7506 perf_iterate_sb(perf_event_mmap_output,
7514 * Check whether inode and address range match filter criteria.
7516 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7517 struct file *file, unsigned long offset,
7520 /* d_inode(NULL) won't be equal to any mapped user-space file */
7521 if (!filter->path.dentry)
7524 if (d_inode(filter->path.dentry) != file_inode(file))
7527 if (filter->offset > offset + size)
7530 if (filter->offset + filter->size < offset)
7536 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7537 struct vm_area_struct *vma,
7538 struct perf_addr_filter_range *fr)
7540 unsigned long vma_size = vma->vm_end - vma->vm_start;
7541 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7542 struct file *file = vma->vm_file;
7544 if (!perf_addr_filter_match(filter, file, off, vma_size))
7547 if (filter->offset < off) {
7548 fr->start = vma->vm_start;
7549 fr->size = min(vma_size, filter->size - (off - filter->offset));
7551 fr->start = vma->vm_start + filter->offset - off;
7552 fr->size = min(vma->vm_end - fr->start, filter->size);
7558 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7560 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7561 struct vm_area_struct *vma = data;
7562 struct perf_addr_filter *filter;
7563 unsigned int restart = 0, count = 0;
7564 unsigned long flags;
7566 if (!has_addr_filter(event))
7572 raw_spin_lock_irqsave(&ifh->lock, flags);
7573 list_for_each_entry(filter, &ifh->list, entry) {
7574 if (perf_addr_filter_vma_adjust(filter, vma,
7575 &event->addr_filter_ranges[count]))
7582 event->addr_filters_gen++;
7583 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7586 perf_event_stop(event, 1);
7590 * Adjust all task's events' filters to the new vma
7592 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7594 struct perf_event_context *ctx;
7598 * Data tracing isn't supported yet and as such there is no need
7599 * to keep track of anything that isn't related to executable code:
7601 if (!(vma->vm_flags & VM_EXEC))
7605 for_each_task_context_nr(ctxn) {
7606 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7610 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7615 void perf_event_mmap(struct vm_area_struct *vma)
7617 struct perf_mmap_event mmap_event;
7619 if (!atomic_read(&nr_mmap_events))
7622 mmap_event = (struct perf_mmap_event){
7628 .type = PERF_RECORD_MMAP,
7629 .misc = PERF_RECORD_MISC_USER,
7634 .start = vma->vm_start,
7635 .len = vma->vm_end - vma->vm_start,
7636 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7638 /* .maj (attr_mmap2 only) */
7639 /* .min (attr_mmap2 only) */
7640 /* .ino (attr_mmap2 only) */
7641 /* .ino_generation (attr_mmap2 only) */
7642 /* .prot (attr_mmap2 only) */
7643 /* .flags (attr_mmap2 only) */
7646 perf_addr_filters_adjust(vma);
7647 perf_event_mmap_event(&mmap_event);
7650 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7651 unsigned long size, u64 flags)
7653 struct perf_output_handle handle;
7654 struct perf_sample_data sample;
7655 struct perf_aux_event {
7656 struct perf_event_header header;
7662 .type = PERF_RECORD_AUX,
7664 .size = sizeof(rec),
7672 perf_event_header__init_id(&rec.header, &sample, event);
7673 ret = perf_output_begin(&handle, event, rec.header.size);
7678 perf_output_put(&handle, rec);
7679 perf_event__output_id_sample(event, &handle, &sample);
7681 perf_output_end(&handle);
7685 * Lost/dropped samples logging
7687 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7689 struct perf_output_handle handle;
7690 struct perf_sample_data sample;
7694 struct perf_event_header header;
7696 } lost_samples_event = {
7698 .type = PERF_RECORD_LOST_SAMPLES,
7700 .size = sizeof(lost_samples_event),
7705 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7707 ret = perf_output_begin(&handle, event,
7708 lost_samples_event.header.size);
7712 perf_output_put(&handle, lost_samples_event);
7713 perf_event__output_id_sample(event, &handle, &sample);
7714 perf_output_end(&handle);
7718 * context_switch tracking
7721 struct perf_switch_event {
7722 struct task_struct *task;
7723 struct task_struct *next_prev;
7726 struct perf_event_header header;
7732 static int perf_event_switch_match(struct perf_event *event)
7734 return event->attr.context_switch;
7737 static void perf_event_switch_output(struct perf_event *event, void *data)
7739 struct perf_switch_event *se = data;
7740 struct perf_output_handle handle;
7741 struct perf_sample_data sample;
7744 if (!perf_event_switch_match(event))
7747 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7748 if (event->ctx->task) {
7749 se->event_id.header.type = PERF_RECORD_SWITCH;
7750 se->event_id.header.size = sizeof(se->event_id.header);
7752 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7753 se->event_id.header.size = sizeof(se->event_id);
7754 se->event_id.next_prev_pid =
7755 perf_event_pid(event, se->next_prev);
7756 se->event_id.next_prev_tid =
7757 perf_event_tid(event, se->next_prev);
7760 perf_event_header__init_id(&se->event_id.header, &sample, event);
7762 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7766 if (event->ctx->task)
7767 perf_output_put(&handle, se->event_id.header);
7769 perf_output_put(&handle, se->event_id);
7771 perf_event__output_id_sample(event, &handle, &sample);
7773 perf_output_end(&handle);
7776 static void perf_event_switch(struct task_struct *task,
7777 struct task_struct *next_prev, bool sched_in)
7779 struct perf_switch_event switch_event;
7781 /* N.B. caller checks nr_switch_events != 0 */
7783 switch_event = (struct perf_switch_event){
7785 .next_prev = next_prev,
7789 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7792 /* .next_prev_pid */
7793 /* .next_prev_tid */
7797 if (!sched_in && task->state == TASK_RUNNING)
7798 switch_event.event_id.header.misc |=
7799 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7801 perf_iterate_sb(perf_event_switch_output,
7807 * IRQ throttle logging
7810 static void perf_log_throttle(struct perf_event *event, int enable)
7812 struct perf_output_handle handle;
7813 struct perf_sample_data sample;
7817 struct perf_event_header header;
7821 } throttle_event = {
7823 .type = PERF_RECORD_THROTTLE,
7825 .size = sizeof(throttle_event),
7827 .time = perf_event_clock(event),
7828 .id = primary_event_id(event),
7829 .stream_id = event->id,
7833 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7835 perf_event_header__init_id(&throttle_event.header, &sample, event);
7837 ret = perf_output_begin(&handle, event,
7838 throttle_event.header.size);
7842 perf_output_put(&handle, throttle_event);
7843 perf_event__output_id_sample(event, &handle, &sample);
7844 perf_output_end(&handle);
7848 * ksymbol register/unregister tracking
7851 struct perf_ksymbol_event {
7855 struct perf_event_header header;
7863 static int perf_event_ksymbol_match(struct perf_event *event)
7865 return event->attr.ksymbol;
7868 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7870 struct perf_ksymbol_event *ksymbol_event = data;
7871 struct perf_output_handle handle;
7872 struct perf_sample_data sample;
7875 if (!perf_event_ksymbol_match(event))
7878 perf_event_header__init_id(&ksymbol_event->event_id.header,
7880 ret = perf_output_begin(&handle, event,
7881 ksymbol_event->event_id.header.size);
7885 perf_output_put(&handle, ksymbol_event->event_id);
7886 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7887 perf_event__output_id_sample(event, &handle, &sample);
7889 perf_output_end(&handle);
7892 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7895 struct perf_ksymbol_event ksymbol_event;
7896 char name[KSYM_NAME_LEN];
7900 if (!atomic_read(&nr_ksymbol_events))
7903 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7904 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7907 strlcpy(name, sym, KSYM_NAME_LEN);
7908 name_len = strlen(name) + 1;
7909 while (!IS_ALIGNED(name_len, sizeof(u64)))
7910 name[name_len++] = '\0';
7911 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7914 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7916 ksymbol_event = (struct perf_ksymbol_event){
7918 .name_len = name_len,
7921 .type = PERF_RECORD_KSYMBOL,
7922 .size = sizeof(ksymbol_event.event_id) +
7927 .ksym_type = ksym_type,
7932 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7935 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7939 * bpf program load/unload tracking
7942 struct perf_bpf_event {
7943 struct bpf_prog *prog;
7945 struct perf_event_header header;
7949 u8 tag[BPF_TAG_SIZE];
7953 static int perf_event_bpf_match(struct perf_event *event)
7955 return event->attr.bpf_event;
7958 static void perf_event_bpf_output(struct perf_event *event, void *data)
7960 struct perf_bpf_event *bpf_event = data;
7961 struct perf_output_handle handle;
7962 struct perf_sample_data sample;
7965 if (!perf_event_bpf_match(event))
7968 perf_event_header__init_id(&bpf_event->event_id.header,
7970 ret = perf_output_begin(&handle, event,
7971 bpf_event->event_id.header.size);
7975 perf_output_put(&handle, bpf_event->event_id);
7976 perf_event__output_id_sample(event, &handle, &sample);
7978 perf_output_end(&handle);
7981 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
7982 enum perf_bpf_event_type type)
7984 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
7985 char sym[KSYM_NAME_LEN];
7988 if (prog->aux->func_cnt == 0) {
7989 bpf_get_prog_name(prog, sym);
7990 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
7991 (u64)(unsigned long)prog->bpf_func,
7992 prog->jited_len, unregister, sym);
7994 for (i = 0; i < prog->aux->func_cnt; i++) {
7995 struct bpf_prog *subprog = prog->aux->func[i];
7997 bpf_get_prog_name(subprog, sym);
7999 PERF_RECORD_KSYMBOL_TYPE_BPF,
8000 (u64)(unsigned long)subprog->bpf_func,
8001 subprog->jited_len, unregister, sym);
8006 void perf_event_bpf_event(struct bpf_prog *prog,
8007 enum perf_bpf_event_type type,
8010 struct perf_bpf_event bpf_event;
8012 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8013 type >= PERF_BPF_EVENT_MAX)
8017 case PERF_BPF_EVENT_PROG_LOAD:
8018 case PERF_BPF_EVENT_PROG_UNLOAD:
8019 if (atomic_read(&nr_ksymbol_events))
8020 perf_event_bpf_emit_ksymbols(prog, type);
8026 if (!atomic_read(&nr_bpf_events))
8029 bpf_event = (struct perf_bpf_event){
8033 .type = PERF_RECORD_BPF_EVENT,
8034 .size = sizeof(bpf_event.event_id),
8038 .id = prog->aux->id,
8042 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8044 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8045 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8048 void perf_event_itrace_started(struct perf_event *event)
8050 event->attach_state |= PERF_ATTACH_ITRACE;
8053 static void perf_log_itrace_start(struct perf_event *event)
8055 struct perf_output_handle handle;
8056 struct perf_sample_data sample;
8057 struct perf_aux_event {
8058 struct perf_event_header header;
8065 event = event->parent;
8067 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8068 event->attach_state & PERF_ATTACH_ITRACE)
8071 rec.header.type = PERF_RECORD_ITRACE_START;
8072 rec.header.misc = 0;
8073 rec.header.size = sizeof(rec);
8074 rec.pid = perf_event_pid(event, current);
8075 rec.tid = perf_event_tid(event, current);
8077 perf_event_header__init_id(&rec.header, &sample, event);
8078 ret = perf_output_begin(&handle, event, rec.header.size);
8083 perf_output_put(&handle, rec);
8084 perf_event__output_id_sample(event, &handle, &sample);
8086 perf_output_end(&handle);
8090 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8092 struct hw_perf_event *hwc = &event->hw;
8096 seq = __this_cpu_read(perf_throttled_seq);
8097 if (seq != hwc->interrupts_seq) {
8098 hwc->interrupts_seq = seq;
8099 hwc->interrupts = 1;
8102 if (unlikely(throttle
8103 && hwc->interrupts >= max_samples_per_tick)) {
8104 __this_cpu_inc(perf_throttled_count);
8105 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8106 hwc->interrupts = MAX_INTERRUPTS;
8107 perf_log_throttle(event, 0);
8112 if (event->attr.freq) {
8113 u64 now = perf_clock();
8114 s64 delta = now - hwc->freq_time_stamp;
8116 hwc->freq_time_stamp = now;
8118 if (delta > 0 && delta < 2*TICK_NSEC)
8119 perf_adjust_period(event, delta, hwc->last_period, true);
8125 int perf_event_account_interrupt(struct perf_event *event)
8127 return __perf_event_account_interrupt(event, 1);
8131 * Generic event overflow handling, sampling.
8134 static int __perf_event_overflow(struct perf_event *event,
8135 int throttle, struct perf_sample_data *data,
8136 struct pt_regs *regs)
8138 int events = atomic_read(&event->event_limit);
8142 * Non-sampling counters might still use the PMI to fold short
8143 * hardware counters, ignore those.
8145 if (unlikely(!is_sampling_event(event)))
8148 ret = __perf_event_account_interrupt(event, throttle);
8151 * XXX event_limit might not quite work as expected on inherited
8155 event->pending_kill = POLL_IN;
8156 if (events && atomic_dec_and_test(&event->event_limit)) {
8158 event->pending_kill = POLL_HUP;
8160 perf_event_disable_inatomic(event);
8163 READ_ONCE(event->overflow_handler)(event, data, regs);
8165 if (*perf_event_fasync(event) && event->pending_kill) {
8166 event->pending_wakeup = 1;
8167 irq_work_queue(&event->pending);
8173 int perf_event_overflow(struct perf_event *event,
8174 struct perf_sample_data *data,
8175 struct pt_regs *regs)
8177 return __perf_event_overflow(event, 1, data, regs);
8181 * Generic software event infrastructure
8184 struct swevent_htable {
8185 struct swevent_hlist *swevent_hlist;
8186 struct mutex hlist_mutex;
8189 /* Recursion avoidance in each contexts */
8190 int recursion[PERF_NR_CONTEXTS];
8193 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8196 * We directly increment event->count and keep a second value in
8197 * event->hw.period_left to count intervals. This period event
8198 * is kept in the range [-sample_period, 0] so that we can use the
8202 u64 perf_swevent_set_period(struct perf_event *event)
8204 struct hw_perf_event *hwc = &event->hw;
8205 u64 period = hwc->last_period;
8209 hwc->last_period = hwc->sample_period;
8212 old = val = local64_read(&hwc->period_left);
8216 nr = div64_u64(period + val, period);
8217 offset = nr * period;
8219 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8225 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8226 struct perf_sample_data *data,
8227 struct pt_regs *regs)
8229 struct hw_perf_event *hwc = &event->hw;
8233 overflow = perf_swevent_set_period(event);
8235 if (hwc->interrupts == MAX_INTERRUPTS)
8238 for (; overflow; overflow--) {
8239 if (__perf_event_overflow(event, throttle,
8242 * We inhibit the overflow from happening when
8243 * hwc->interrupts == MAX_INTERRUPTS.
8251 static void perf_swevent_event(struct perf_event *event, u64 nr,
8252 struct perf_sample_data *data,
8253 struct pt_regs *regs)
8255 struct hw_perf_event *hwc = &event->hw;
8257 local64_add(nr, &event->count);
8262 if (!is_sampling_event(event))
8265 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8267 return perf_swevent_overflow(event, 1, data, regs);
8269 data->period = event->hw.last_period;
8271 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8272 return perf_swevent_overflow(event, 1, data, regs);
8274 if (local64_add_negative(nr, &hwc->period_left))
8277 perf_swevent_overflow(event, 0, data, regs);
8280 static int perf_exclude_event(struct perf_event *event,
8281 struct pt_regs *regs)
8283 if (event->hw.state & PERF_HES_STOPPED)
8287 if (event->attr.exclude_user && user_mode(regs))
8290 if (event->attr.exclude_kernel && !user_mode(regs))
8297 static int perf_swevent_match(struct perf_event *event,
8298 enum perf_type_id type,
8300 struct perf_sample_data *data,
8301 struct pt_regs *regs)
8303 if (event->attr.type != type)
8306 if (event->attr.config != event_id)
8309 if (perf_exclude_event(event, regs))
8315 static inline u64 swevent_hash(u64 type, u32 event_id)
8317 u64 val = event_id | (type << 32);
8319 return hash_64(val, SWEVENT_HLIST_BITS);
8322 static inline struct hlist_head *
8323 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8325 u64 hash = swevent_hash(type, event_id);
8327 return &hlist->heads[hash];
8330 /* For the read side: events when they trigger */
8331 static inline struct hlist_head *
8332 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8334 struct swevent_hlist *hlist;
8336 hlist = rcu_dereference(swhash->swevent_hlist);
8340 return __find_swevent_head(hlist, type, event_id);
8343 /* For the event head insertion and removal in the hlist */
8344 static inline struct hlist_head *
8345 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8347 struct swevent_hlist *hlist;
8348 u32 event_id = event->attr.config;
8349 u64 type = event->attr.type;
8352 * Event scheduling is always serialized against hlist allocation
8353 * and release. Which makes the protected version suitable here.
8354 * The context lock guarantees that.
8356 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8357 lockdep_is_held(&event->ctx->lock));
8361 return __find_swevent_head(hlist, type, event_id);
8364 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8366 struct perf_sample_data *data,
8367 struct pt_regs *regs)
8369 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8370 struct perf_event *event;
8371 struct hlist_head *head;
8374 head = find_swevent_head_rcu(swhash, type, event_id);
8378 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8379 if (perf_swevent_match(event, type, event_id, data, regs))
8380 perf_swevent_event(event, nr, data, regs);
8386 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8388 int perf_swevent_get_recursion_context(void)
8390 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8392 return get_recursion_context(swhash->recursion);
8394 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8396 void perf_swevent_put_recursion_context(int rctx)
8398 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8400 put_recursion_context(swhash->recursion, rctx);
8403 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8405 struct perf_sample_data data;
8407 if (WARN_ON_ONCE(!regs))
8410 perf_sample_data_init(&data, addr, 0);
8411 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8414 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8418 preempt_disable_notrace();
8419 rctx = perf_swevent_get_recursion_context();
8420 if (unlikely(rctx < 0))
8423 ___perf_sw_event(event_id, nr, regs, addr);
8425 perf_swevent_put_recursion_context(rctx);
8427 preempt_enable_notrace();
8430 static void perf_swevent_read(struct perf_event *event)
8434 static int perf_swevent_add(struct perf_event *event, int flags)
8436 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8437 struct hw_perf_event *hwc = &event->hw;
8438 struct hlist_head *head;
8440 if (is_sampling_event(event)) {
8441 hwc->last_period = hwc->sample_period;
8442 perf_swevent_set_period(event);
8445 hwc->state = !(flags & PERF_EF_START);
8447 head = find_swevent_head(swhash, event);
8448 if (WARN_ON_ONCE(!head))
8451 hlist_add_head_rcu(&event->hlist_entry, head);
8452 perf_event_update_userpage(event);
8457 static void perf_swevent_del(struct perf_event *event, int flags)
8459 hlist_del_rcu(&event->hlist_entry);
8462 static void perf_swevent_start(struct perf_event *event, int flags)
8464 event->hw.state = 0;
8467 static void perf_swevent_stop(struct perf_event *event, int flags)
8469 event->hw.state = PERF_HES_STOPPED;
8472 /* Deref the hlist from the update side */
8473 static inline struct swevent_hlist *
8474 swevent_hlist_deref(struct swevent_htable *swhash)
8476 return rcu_dereference_protected(swhash->swevent_hlist,
8477 lockdep_is_held(&swhash->hlist_mutex));
8480 static void swevent_hlist_release(struct swevent_htable *swhash)
8482 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8487 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8488 kfree_rcu(hlist, rcu_head);
8491 static void swevent_hlist_put_cpu(int cpu)
8493 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8495 mutex_lock(&swhash->hlist_mutex);
8497 if (!--swhash->hlist_refcount)
8498 swevent_hlist_release(swhash);
8500 mutex_unlock(&swhash->hlist_mutex);
8503 static void swevent_hlist_put(void)
8507 for_each_possible_cpu(cpu)
8508 swevent_hlist_put_cpu(cpu);
8511 static int swevent_hlist_get_cpu(int cpu)
8513 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8516 mutex_lock(&swhash->hlist_mutex);
8517 if (!swevent_hlist_deref(swhash) &&
8518 cpumask_test_cpu(cpu, perf_online_mask)) {
8519 struct swevent_hlist *hlist;
8521 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8526 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8528 swhash->hlist_refcount++;
8530 mutex_unlock(&swhash->hlist_mutex);
8535 static int swevent_hlist_get(void)
8537 int err, cpu, failed_cpu;
8539 mutex_lock(&pmus_lock);
8540 for_each_possible_cpu(cpu) {
8541 err = swevent_hlist_get_cpu(cpu);
8547 mutex_unlock(&pmus_lock);
8550 for_each_possible_cpu(cpu) {
8551 if (cpu == failed_cpu)
8553 swevent_hlist_put_cpu(cpu);
8555 mutex_unlock(&pmus_lock);
8559 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8561 static void sw_perf_event_destroy(struct perf_event *event)
8563 u64 event_id = event->attr.config;
8565 WARN_ON(event->parent);
8567 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8568 swevent_hlist_put();
8571 static int perf_swevent_init(struct perf_event *event)
8573 u64 event_id = event->attr.config;
8575 if (event->attr.type != PERF_TYPE_SOFTWARE)
8579 * no branch sampling for software events
8581 if (has_branch_stack(event))
8585 case PERF_COUNT_SW_CPU_CLOCK:
8586 case PERF_COUNT_SW_TASK_CLOCK:
8593 if (event_id >= PERF_COUNT_SW_MAX)
8596 if (!event->parent) {
8599 err = swevent_hlist_get();
8603 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8604 event->destroy = sw_perf_event_destroy;
8610 static struct pmu perf_swevent = {
8611 .task_ctx_nr = perf_sw_context,
8613 .capabilities = PERF_PMU_CAP_NO_NMI,
8615 .event_init = perf_swevent_init,
8616 .add = perf_swevent_add,
8617 .del = perf_swevent_del,
8618 .start = perf_swevent_start,
8619 .stop = perf_swevent_stop,
8620 .read = perf_swevent_read,
8623 #ifdef CONFIG_EVENT_TRACING
8625 static int perf_tp_filter_match(struct perf_event *event,
8626 struct perf_sample_data *data)
8628 void *record = data->raw->frag.data;
8630 /* only top level events have filters set */
8632 event = event->parent;
8634 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8639 static int perf_tp_event_match(struct perf_event *event,
8640 struct perf_sample_data *data,
8641 struct pt_regs *regs)
8643 if (event->hw.state & PERF_HES_STOPPED)
8646 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8648 if (event->attr.exclude_kernel && !user_mode(regs))
8651 if (!perf_tp_filter_match(event, data))
8657 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8658 struct trace_event_call *call, u64 count,
8659 struct pt_regs *regs, struct hlist_head *head,
8660 struct task_struct *task)
8662 if (bpf_prog_array_valid(call)) {
8663 *(struct pt_regs **)raw_data = regs;
8664 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8665 perf_swevent_put_recursion_context(rctx);
8669 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8672 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8674 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8675 struct pt_regs *regs, struct hlist_head *head, int rctx,
8676 struct task_struct *task)
8678 struct perf_sample_data data;
8679 struct perf_event *event;
8681 struct perf_raw_record raw = {
8688 perf_sample_data_init(&data, 0, 0);
8691 perf_trace_buf_update(record, event_type);
8693 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8694 if (perf_tp_event_match(event, &data, regs))
8695 perf_swevent_event(event, count, &data, regs);
8699 * If we got specified a target task, also iterate its context and
8700 * deliver this event there too.
8702 if (task && task != current) {
8703 struct perf_event_context *ctx;
8704 struct trace_entry *entry = record;
8707 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8711 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8712 if (event->cpu != smp_processor_id())
8714 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8716 if (event->attr.config != entry->type)
8718 if (perf_tp_event_match(event, &data, regs))
8719 perf_swevent_event(event, count, &data, regs);
8725 perf_swevent_put_recursion_context(rctx);
8727 EXPORT_SYMBOL_GPL(perf_tp_event);
8729 static void tp_perf_event_destroy(struct perf_event *event)
8731 perf_trace_destroy(event);
8734 static int perf_tp_event_init(struct perf_event *event)
8738 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8742 * no branch sampling for tracepoint events
8744 if (has_branch_stack(event))
8747 err = perf_trace_init(event);
8751 event->destroy = tp_perf_event_destroy;
8756 static struct pmu perf_tracepoint = {
8757 .task_ctx_nr = perf_sw_context,
8759 .event_init = perf_tp_event_init,
8760 .add = perf_trace_add,
8761 .del = perf_trace_del,
8762 .start = perf_swevent_start,
8763 .stop = perf_swevent_stop,
8764 .read = perf_swevent_read,
8767 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8769 * Flags in config, used by dynamic PMU kprobe and uprobe
8770 * The flags should match following PMU_FORMAT_ATTR().
8772 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8773 * if not set, create kprobe/uprobe
8775 * The following values specify a reference counter (or semaphore in the
8776 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8777 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8779 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8780 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8782 enum perf_probe_config {
8783 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8784 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8785 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8788 PMU_FORMAT_ATTR(retprobe, "config:0");
8791 #ifdef CONFIG_KPROBE_EVENTS
8792 static struct attribute *kprobe_attrs[] = {
8793 &format_attr_retprobe.attr,
8797 static struct attribute_group kprobe_format_group = {
8799 .attrs = kprobe_attrs,
8802 static const struct attribute_group *kprobe_attr_groups[] = {
8803 &kprobe_format_group,
8807 static int perf_kprobe_event_init(struct perf_event *event);
8808 static struct pmu perf_kprobe = {
8809 .task_ctx_nr = perf_sw_context,
8810 .event_init = perf_kprobe_event_init,
8811 .add = perf_trace_add,
8812 .del = perf_trace_del,
8813 .start = perf_swevent_start,
8814 .stop = perf_swevent_stop,
8815 .read = perf_swevent_read,
8816 .attr_groups = kprobe_attr_groups,
8819 static int perf_kprobe_event_init(struct perf_event *event)
8824 if (event->attr.type != perf_kprobe.type)
8827 if (!capable(CAP_SYS_ADMIN))
8831 * no branch sampling for probe events
8833 if (has_branch_stack(event))
8836 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8837 err = perf_kprobe_init(event, is_retprobe);
8841 event->destroy = perf_kprobe_destroy;
8845 #endif /* CONFIG_KPROBE_EVENTS */
8847 #ifdef CONFIG_UPROBE_EVENTS
8848 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8850 static struct attribute *uprobe_attrs[] = {
8851 &format_attr_retprobe.attr,
8852 &format_attr_ref_ctr_offset.attr,
8856 static struct attribute_group uprobe_format_group = {
8858 .attrs = uprobe_attrs,
8861 static const struct attribute_group *uprobe_attr_groups[] = {
8862 &uprobe_format_group,
8866 static int perf_uprobe_event_init(struct perf_event *event);
8867 static struct pmu perf_uprobe = {
8868 .task_ctx_nr = perf_sw_context,
8869 .event_init = perf_uprobe_event_init,
8870 .add = perf_trace_add,
8871 .del = perf_trace_del,
8872 .start = perf_swevent_start,
8873 .stop = perf_swevent_stop,
8874 .read = perf_swevent_read,
8875 .attr_groups = uprobe_attr_groups,
8878 static int perf_uprobe_event_init(struct perf_event *event)
8881 unsigned long ref_ctr_offset;
8884 if (event->attr.type != perf_uprobe.type)
8887 if (!capable(CAP_SYS_ADMIN))
8891 * no branch sampling for probe events
8893 if (has_branch_stack(event))
8896 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8897 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8898 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8902 event->destroy = perf_uprobe_destroy;
8906 #endif /* CONFIG_UPROBE_EVENTS */
8908 static inline void perf_tp_register(void)
8910 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8911 #ifdef CONFIG_KPROBE_EVENTS
8912 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8914 #ifdef CONFIG_UPROBE_EVENTS
8915 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8919 static void perf_event_free_filter(struct perf_event *event)
8921 ftrace_profile_free_filter(event);
8924 #ifdef CONFIG_BPF_SYSCALL
8925 static void bpf_overflow_handler(struct perf_event *event,
8926 struct perf_sample_data *data,
8927 struct pt_regs *regs)
8929 struct bpf_perf_event_data_kern ctx = {
8935 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8937 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8940 ret = BPF_PROG_RUN(event->prog, &ctx);
8943 __this_cpu_dec(bpf_prog_active);
8948 event->orig_overflow_handler(event, data, regs);
8951 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8953 struct bpf_prog *prog;
8955 if (event->overflow_handler_context)
8956 /* hw breakpoint or kernel counter */
8962 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8964 return PTR_ERR(prog);
8967 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8968 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8972 static void perf_event_free_bpf_handler(struct perf_event *event)
8974 struct bpf_prog *prog = event->prog;
8979 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8984 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8988 static void perf_event_free_bpf_handler(struct perf_event *event)
8994 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8995 * with perf_event_open()
8997 static inline bool perf_event_is_tracing(struct perf_event *event)
8999 if (event->pmu == &perf_tracepoint)
9001 #ifdef CONFIG_KPROBE_EVENTS
9002 if (event->pmu == &perf_kprobe)
9005 #ifdef CONFIG_UPROBE_EVENTS
9006 if (event->pmu == &perf_uprobe)
9012 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9014 bool is_kprobe, is_tracepoint, is_syscall_tp;
9015 struct bpf_prog *prog;
9018 if (!perf_event_is_tracing(event))
9019 return perf_event_set_bpf_handler(event, prog_fd);
9021 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9022 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9023 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9024 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9025 /* bpf programs can only be attached to u/kprobe or tracepoint */
9028 prog = bpf_prog_get(prog_fd);
9030 return PTR_ERR(prog);
9032 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9033 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9034 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9035 /* valid fd, but invalid bpf program type */
9040 /* Kprobe override only works for kprobes, not uprobes. */
9041 if (prog->kprobe_override &&
9042 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9047 if (is_tracepoint || is_syscall_tp) {
9048 int off = trace_event_get_offsets(event->tp_event);
9050 if (prog->aux->max_ctx_offset > off) {
9056 ret = perf_event_attach_bpf_prog(event, prog);
9062 static void perf_event_free_bpf_prog(struct perf_event *event)
9064 if (!perf_event_is_tracing(event)) {
9065 perf_event_free_bpf_handler(event);
9068 perf_event_detach_bpf_prog(event);
9073 static inline void perf_tp_register(void)
9077 static void perf_event_free_filter(struct perf_event *event)
9081 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9086 static void perf_event_free_bpf_prog(struct perf_event *event)
9089 #endif /* CONFIG_EVENT_TRACING */
9091 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9092 void perf_bp_event(struct perf_event *bp, void *data)
9094 struct perf_sample_data sample;
9095 struct pt_regs *regs = data;
9097 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9099 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9100 perf_swevent_event(bp, 1, &sample, regs);
9105 * Allocate a new address filter
9107 static struct perf_addr_filter *
9108 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9110 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9111 struct perf_addr_filter *filter;
9113 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9117 INIT_LIST_HEAD(&filter->entry);
9118 list_add_tail(&filter->entry, filters);
9123 static void free_filters_list(struct list_head *filters)
9125 struct perf_addr_filter *filter, *iter;
9127 list_for_each_entry_safe(filter, iter, filters, entry) {
9128 path_put(&filter->path);
9129 list_del(&filter->entry);
9135 * Free existing address filters and optionally install new ones
9137 static void perf_addr_filters_splice(struct perf_event *event,
9138 struct list_head *head)
9140 unsigned long flags;
9143 if (!has_addr_filter(event))
9146 /* don't bother with children, they don't have their own filters */
9150 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9152 list_splice_init(&event->addr_filters.list, &list);
9154 list_splice(head, &event->addr_filters.list);
9156 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9158 free_filters_list(&list);
9162 * Scan through mm's vmas and see if one of them matches the
9163 * @filter; if so, adjust filter's address range.
9164 * Called with mm::mmap_sem down for reading.
9166 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9167 struct mm_struct *mm,
9168 struct perf_addr_filter_range *fr)
9170 struct vm_area_struct *vma;
9172 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9176 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9182 * Update event's address range filters based on the
9183 * task's existing mappings, if any.
9185 static void perf_event_addr_filters_apply(struct perf_event *event)
9187 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9188 struct task_struct *task = READ_ONCE(event->ctx->task);
9189 struct perf_addr_filter *filter;
9190 struct mm_struct *mm = NULL;
9191 unsigned int count = 0;
9192 unsigned long flags;
9195 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9196 * will stop on the parent's child_mutex that our caller is also holding
9198 if (task == TASK_TOMBSTONE)
9201 if (ifh->nr_file_filters) {
9202 mm = get_task_mm(event->ctx->task);
9206 down_read(&mm->mmap_sem);
9209 raw_spin_lock_irqsave(&ifh->lock, flags);
9210 list_for_each_entry(filter, &ifh->list, entry) {
9211 if (filter->path.dentry) {
9213 * Adjust base offset if the filter is associated to a
9214 * binary that needs to be mapped:
9216 event->addr_filter_ranges[count].start = 0;
9217 event->addr_filter_ranges[count].size = 0;
9219 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9221 event->addr_filter_ranges[count].start = filter->offset;
9222 event->addr_filter_ranges[count].size = filter->size;
9228 event->addr_filters_gen++;
9229 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9231 if (ifh->nr_file_filters) {
9232 up_read(&mm->mmap_sem);
9238 perf_event_stop(event, 1);
9242 * Address range filtering: limiting the data to certain
9243 * instruction address ranges. Filters are ioctl()ed to us from
9244 * userspace as ascii strings.
9246 * Filter string format:
9249 * where ACTION is one of the
9250 * * "filter": limit the trace to this region
9251 * * "start": start tracing from this address
9252 * * "stop": stop tracing at this address/region;
9254 * * for kernel addresses: <start address>[/<size>]
9255 * * for object files: <start address>[/<size>]@</path/to/object/file>
9257 * if <size> is not specified or is zero, the range is treated as a single
9258 * address; not valid for ACTION=="filter".
9272 IF_STATE_ACTION = 0,
9277 static const match_table_t if_tokens = {
9278 { IF_ACT_FILTER, "filter" },
9279 { IF_ACT_START, "start" },
9280 { IF_ACT_STOP, "stop" },
9281 { IF_SRC_FILE, "%u/%u@%s" },
9282 { IF_SRC_KERNEL, "%u/%u" },
9283 { IF_SRC_FILEADDR, "%u@%s" },
9284 { IF_SRC_KERNELADDR, "%u" },
9285 { IF_ACT_NONE, NULL },
9289 * Address filter string parser
9292 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9293 struct list_head *filters)
9295 struct perf_addr_filter *filter = NULL;
9296 char *start, *orig, *filename = NULL;
9297 substring_t args[MAX_OPT_ARGS];
9298 int state = IF_STATE_ACTION, token;
9299 unsigned int kernel = 0;
9302 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9306 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9307 static const enum perf_addr_filter_action_t actions[] = {
9308 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9309 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9310 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9317 /* filter definition begins */
9318 if (state == IF_STATE_ACTION) {
9319 filter = perf_addr_filter_new(event, filters);
9324 token = match_token(start, if_tokens, args);
9329 if (state != IF_STATE_ACTION)
9332 filter->action = actions[token];
9333 state = IF_STATE_SOURCE;
9336 case IF_SRC_KERNELADDR:
9341 case IF_SRC_FILEADDR:
9343 if (state != IF_STATE_SOURCE)
9347 ret = kstrtoul(args[0].from, 0, &filter->offset);
9351 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9353 ret = kstrtoul(args[1].from, 0, &filter->size);
9358 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9359 int fpos = token == IF_SRC_FILE ? 2 : 1;
9361 filename = match_strdup(&args[fpos]);
9368 state = IF_STATE_END;
9376 * Filter definition is fully parsed, validate and install it.
9377 * Make sure that it doesn't contradict itself or the event's
9380 if (state == IF_STATE_END) {
9382 if (kernel && event->attr.exclude_kernel)
9386 * ACTION "filter" must have a non-zero length region
9389 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9398 * For now, we only support file-based filters
9399 * in per-task events; doing so for CPU-wide
9400 * events requires additional context switching
9401 * trickery, since same object code will be
9402 * mapped at different virtual addresses in
9403 * different processes.
9406 if (!event->ctx->task)
9407 goto fail_free_name;
9409 /* look up the path and grab its inode */
9410 ret = kern_path(filename, LOOKUP_FOLLOW,
9413 goto fail_free_name;
9419 if (!filter->path.dentry ||
9420 !S_ISREG(d_inode(filter->path.dentry)
9424 event->addr_filters.nr_file_filters++;
9427 /* ready to consume more filters */
9428 state = IF_STATE_ACTION;
9433 if (state != IF_STATE_ACTION)
9443 free_filters_list(filters);
9450 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9456 * Since this is called in perf_ioctl() path, we're already holding
9459 lockdep_assert_held(&event->ctx->mutex);
9461 if (WARN_ON_ONCE(event->parent))
9464 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9466 goto fail_clear_files;
9468 ret = event->pmu->addr_filters_validate(&filters);
9470 goto fail_free_filters;
9472 /* remove existing filters, if any */
9473 perf_addr_filters_splice(event, &filters);
9475 /* install new filters */
9476 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9481 free_filters_list(&filters);
9484 event->addr_filters.nr_file_filters = 0;
9489 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9494 filter_str = strndup_user(arg, PAGE_SIZE);
9495 if (IS_ERR(filter_str))
9496 return PTR_ERR(filter_str);
9498 #ifdef CONFIG_EVENT_TRACING
9499 if (perf_event_is_tracing(event)) {
9500 struct perf_event_context *ctx = event->ctx;
9503 * Beware, here be dragons!!
9505 * the tracepoint muck will deadlock against ctx->mutex, but
9506 * the tracepoint stuff does not actually need it. So
9507 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9508 * already have a reference on ctx.
9510 * This can result in event getting moved to a different ctx,
9511 * but that does not affect the tracepoint state.
9513 mutex_unlock(&ctx->mutex);
9514 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9515 mutex_lock(&ctx->mutex);
9518 if (has_addr_filter(event))
9519 ret = perf_event_set_addr_filter(event, filter_str);
9526 * hrtimer based swevent callback
9529 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9531 enum hrtimer_restart ret = HRTIMER_RESTART;
9532 struct perf_sample_data data;
9533 struct pt_regs *regs;
9534 struct perf_event *event;
9537 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9539 if (event->state != PERF_EVENT_STATE_ACTIVE)
9540 return HRTIMER_NORESTART;
9542 event->pmu->read(event);
9544 perf_sample_data_init(&data, 0, event->hw.last_period);
9545 regs = get_irq_regs();
9547 if (regs && !perf_exclude_event(event, regs)) {
9548 if (!(event->attr.exclude_idle && is_idle_task(current)))
9549 if (__perf_event_overflow(event, 1, &data, regs))
9550 ret = HRTIMER_NORESTART;
9553 period = max_t(u64, 10000, event->hw.sample_period);
9554 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9559 static void perf_swevent_start_hrtimer(struct perf_event *event)
9561 struct hw_perf_event *hwc = &event->hw;
9564 if (!is_sampling_event(event))
9567 period = local64_read(&hwc->period_left);
9572 local64_set(&hwc->period_left, 0);
9574 period = max_t(u64, 10000, hwc->sample_period);
9576 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9577 HRTIMER_MODE_REL_PINNED_HARD);
9580 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9582 struct hw_perf_event *hwc = &event->hw;
9584 if (is_sampling_event(event)) {
9585 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9586 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9588 hrtimer_cancel(&hwc->hrtimer);
9592 static void perf_swevent_init_hrtimer(struct perf_event *event)
9594 struct hw_perf_event *hwc = &event->hw;
9596 if (!is_sampling_event(event))
9599 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
9600 hwc->hrtimer.function = perf_swevent_hrtimer;
9603 * Since hrtimers have a fixed rate, we can do a static freq->period
9604 * mapping and avoid the whole period adjust feedback stuff.
9606 if (event->attr.freq) {
9607 long freq = event->attr.sample_freq;
9609 event->attr.sample_period = NSEC_PER_SEC / freq;
9610 hwc->sample_period = event->attr.sample_period;
9611 local64_set(&hwc->period_left, hwc->sample_period);
9612 hwc->last_period = hwc->sample_period;
9613 event->attr.freq = 0;
9618 * Software event: cpu wall time clock
9621 static void cpu_clock_event_update(struct perf_event *event)
9626 now = local_clock();
9627 prev = local64_xchg(&event->hw.prev_count, now);
9628 local64_add(now - prev, &event->count);
9631 static void cpu_clock_event_start(struct perf_event *event, int flags)
9633 local64_set(&event->hw.prev_count, local_clock());
9634 perf_swevent_start_hrtimer(event);
9637 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9639 perf_swevent_cancel_hrtimer(event);
9640 cpu_clock_event_update(event);
9643 static int cpu_clock_event_add(struct perf_event *event, int flags)
9645 if (flags & PERF_EF_START)
9646 cpu_clock_event_start(event, flags);
9647 perf_event_update_userpage(event);
9652 static void cpu_clock_event_del(struct perf_event *event, int flags)
9654 cpu_clock_event_stop(event, flags);
9657 static void cpu_clock_event_read(struct perf_event *event)
9659 cpu_clock_event_update(event);
9662 static int cpu_clock_event_init(struct perf_event *event)
9664 if (event->attr.type != PERF_TYPE_SOFTWARE)
9667 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9671 * no branch sampling for software events
9673 if (has_branch_stack(event))
9676 perf_swevent_init_hrtimer(event);
9681 static struct pmu perf_cpu_clock = {
9682 .task_ctx_nr = perf_sw_context,
9684 .capabilities = PERF_PMU_CAP_NO_NMI,
9686 .event_init = cpu_clock_event_init,
9687 .add = cpu_clock_event_add,
9688 .del = cpu_clock_event_del,
9689 .start = cpu_clock_event_start,
9690 .stop = cpu_clock_event_stop,
9691 .read = cpu_clock_event_read,
9695 * Software event: task time clock
9698 static void task_clock_event_update(struct perf_event *event, u64 now)
9703 prev = local64_xchg(&event->hw.prev_count, now);
9705 local64_add(delta, &event->count);
9708 static void task_clock_event_start(struct perf_event *event, int flags)
9710 local64_set(&event->hw.prev_count, event->ctx->time);
9711 perf_swevent_start_hrtimer(event);
9714 static void task_clock_event_stop(struct perf_event *event, int flags)
9716 perf_swevent_cancel_hrtimer(event);
9717 task_clock_event_update(event, event->ctx->time);
9720 static int task_clock_event_add(struct perf_event *event, int flags)
9722 if (flags & PERF_EF_START)
9723 task_clock_event_start(event, flags);
9724 perf_event_update_userpage(event);
9729 static void task_clock_event_del(struct perf_event *event, int flags)
9731 task_clock_event_stop(event, PERF_EF_UPDATE);
9734 static void task_clock_event_read(struct perf_event *event)
9736 u64 now = perf_clock();
9737 u64 delta = now - event->ctx->timestamp;
9738 u64 time = event->ctx->time + delta;
9740 task_clock_event_update(event, time);
9743 static int task_clock_event_init(struct perf_event *event)
9745 if (event->attr.type != PERF_TYPE_SOFTWARE)
9748 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9752 * no branch sampling for software events
9754 if (has_branch_stack(event))
9757 perf_swevent_init_hrtimer(event);
9762 static struct pmu perf_task_clock = {
9763 .task_ctx_nr = perf_sw_context,
9765 .capabilities = PERF_PMU_CAP_NO_NMI,
9767 .event_init = task_clock_event_init,
9768 .add = task_clock_event_add,
9769 .del = task_clock_event_del,
9770 .start = task_clock_event_start,
9771 .stop = task_clock_event_stop,
9772 .read = task_clock_event_read,
9775 static void perf_pmu_nop_void(struct pmu *pmu)
9779 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9783 static int perf_pmu_nop_int(struct pmu *pmu)
9788 static int perf_event_nop_int(struct perf_event *event, u64 value)
9793 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9795 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9797 __this_cpu_write(nop_txn_flags, flags);
9799 if (flags & ~PERF_PMU_TXN_ADD)
9802 perf_pmu_disable(pmu);
9805 static int perf_pmu_commit_txn(struct pmu *pmu)
9807 unsigned int flags = __this_cpu_read(nop_txn_flags);
9809 __this_cpu_write(nop_txn_flags, 0);
9811 if (flags & ~PERF_PMU_TXN_ADD)
9814 perf_pmu_enable(pmu);
9818 static void perf_pmu_cancel_txn(struct pmu *pmu)
9820 unsigned int flags = __this_cpu_read(nop_txn_flags);
9822 __this_cpu_write(nop_txn_flags, 0);
9824 if (flags & ~PERF_PMU_TXN_ADD)
9827 perf_pmu_enable(pmu);
9830 static int perf_event_idx_default(struct perf_event *event)
9836 * Ensures all contexts with the same task_ctx_nr have the same
9837 * pmu_cpu_context too.
9839 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9846 list_for_each_entry(pmu, &pmus, entry) {
9847 if (pmu->task_ctx_nr == ctxn)
9848 return pmu->pmu_cpu_context;
9854 static void free_pmu_context(struct pmu *pmu)
9857 * Static contexts such as perf_sw_context have a global lifetime
9858 * and may be shared between different PMUs. Avoid freeing them
9859 * when a single PMU is going away.
9861 if (pmu->task_ctx_nr > perf_invalid_context)
9864 free_percpu(pmu->pmu_cpu_context);
9868 * Let userspace know that this PMU supports address range filtering:
9870 static ssize_t nr_addr_filters_show(struct device *dev,
9871 struct device_attribute *attr,
9874 struct pmu *pmu = dev_get_drvdata(dev);
9876 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9878 DEVICE_ATTR_RO(nr_addr_filters);
9880 static struct idr pmu_idr;
9883 type_show(struct device *dev, struct device_attribute *attr, char *page)
9885 struct pmu *pmu = dev_get_drvdata(dev);
9887 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9889 static DEVICE_ATTR_RO(type);
9892 perf_event_mux_interval_ms_show(struct device *dev,
9893 struct device_attribute *attr,
9896 struct pmu *pmu = dev_get_drvdata(dev);
9898 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9901 static DEFINE_MUTEX(mux_interval_mutex);
9904 perf_event_mux_interval_ms_store(struct device *dev,
9905 struct device_attribute *attr,
9906 const char *buf, size_t count)
9908 struct pmu *pmu = dev_get_drvdata(dev);
9909 int timer, cpu, ret;
9911 ret = kstrtoint(buf, 0, &timer);
9918 /* same value, noting to do */
9919 if (timer == pmu->hrtimer_interval_ms)
9922 mutex_lock(&mux_interval_mutex);
9923 pmu->hrtimer_interval_ms = timer;
9925 /* update all cpuctx for this PMU */
9927 for_each_online_cpu(cpu) {
9928 struct perf_cpu_context *cpuctx;
9929 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9930 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9932 cpu_function_call(cpu,
9933 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9936 mutex_unlock(&mux_interval_mutex);
9940 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9942 static struct attribute *pmu_dev_attrs[] = {
9943 &dev_attr_type.attr,
9944 &dev_attr_perf_event_mux_interval_ms.attr,
9947 ATTRIBUTE_GROUPS(pmu_dev);
9949 static int pmu_bus_running;
9950 static struct bus_type pmu_bus = {
9951 .name = "event_source",
9952 .dev_groups = pmu_dev_groups,
9955 static void pmu_dev_release(struct device *dev)
9960 static int pmu_dev_alloc(struct pmu *pmu)
9964 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9968 pmu->dev->groups = pmu->attr_groups;
9969 device_initialize(pmu->dev);
9970 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9974 dev_set_drvdata(pmu->dev, pmu);
9975 pmu->dev->bus = &pmu_bus;
9976 pmu->dev->release = pmu_dev_release;
9977 ret = device_add(pmu->dev);
9981 /* For PMUs with address filters, throw in an extra attribute: */
9982 if (pmu->nr_addr_filters)
9983 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9988 if (pmu->attr_update)
9989 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
9998 device_del(pmu->dev);
10001 put_device(pmu->dev);
10005 static struct lock_class_key cpuctx_mutex;
10006 static struct lock_class_key cpuctx_lock;
10008 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10012 mutex_lock(&pmus_lock);
10014 pmu->pmu_disable_count = alloc_percpu(int);
10015 if (!pmu->pmu_disable_count)
10024 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
10032 if (pmu_bus_running) {
10033 ret = pmu_dev_alloc(pmu);
10039 if (pmu->task_ctx_nr == perf_hw_context) {
10040 static int hw_context_taken = 0;
10043 * Other than systems with heterogeneous CPUs, it never makes
10044 * sense for two PMUs to share perf_hw_context. PMUs which are
10045 * uncore must use perf_invalid_context.
10047 if (WARN_ON_ONCE(hw_context_taken &&
10048 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10049 pmu->task_ctx_nr = perf_invalid_context;
10051 hw_context_taken = 1;
10054 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10055 if (pmu->pmu_cpu_context)
10056 goto got_cpu_context;
10059 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10060 if (!pmu->pmu_cpu_context)
10063 for_each_possible_cpu(cpu) {
10064 struct perf_cpu_context *cpuctx;
10066 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10067 __perf_event_init_context(&cpuctx->ctx);
10068 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10069 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10070 cpuctx->ctx.pmu = pmu;
10071 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10073 __perf_mux_hrtimer_init(cpuctx, cpu);
10077 if (!pmu->start_txn) {
10078 if (pmu->pmu_enable) {
10080 * If we have pmu_enable/pmu_disable calls, install
10081 * transaction stubs that use that to try and batch
10082 * hardware accesses.
10084 pmu->start_txn = perf_pmu_start_txn;
10085 pmu->commit_txn = perf_pmu_commit_txn;
10086 pmu->cancel_txn = perf_pmu_cancel_txn;
10088 pmu->start_txn = perf_pmu_nop_txn;
10089 pmu->commit_txn = perf_pmu_nop_int;
10090 pmu->cancel_txn = perf_pmu_nop_void;
10094 if (!pmu->pmu_enable) {
10095 pmu->pmu_enable = perf_pmu_nop_void;
10096 pmu->pmu_disable = perf_pmu_nop_void;
10099 if (!pmu->check_period)
10100 pmu->check_period = perf_event_nop_int;
10102 if (!pmu->event_idx)
10103 pmu->event_idx = perf_event_idx_default;
10105 list_add_rcu(&pmu->entry, &pmus);
10106 atomic_set(&pmu->exclusive_cnt, 0);
10109 mutex_unlock(&pmus_lock);
10114 device_del(pmu->dev);
10115 put_device(pmu->dev);
10118 if (pmu->type >= PERF_TYPE_MAX)
10119 idr_remove(&pmu_idr, pmu->type);
10122 free_percpu(pmu->pmu_disable_count);
10125 EXPORT_SYMBOL_GPL(perf_pmu_register);
10127 void perf_pmu_unregister(struct pmu *pmu)
10129 mutex_lock(&pmus_lock);
10130 list_del_rcu(&pmu->entry);
10133 * We dereference the pmu list under both SRCU and regular RCU, so
10134 * synchronize against both of those.
10136 synchronize_srcu(&pmus_srcu);
10139 free_percpu(pmu->pmu_disable_count);
10140 if (pmu->type >= PERF_TYPE_MAX)
10141 idr_remove(&pmu_idr, pmu->type);
10142 if (pmu_bus_running) {
10143 if (pmu->nr_addr_filters)
10144 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10145 device_del(pmu->dev);
10146 put_device(pmu->dev);
10148 free_pmu_context(pmu);
10149 mutex_unlock(&pmus_lock);
10151 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10153 static inline bool has_extended_regs(struct perf_event *event)
10155 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10156 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10159 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10161 struct perf_event_context *ctx = NULL;
10164 if (!try_module_get(pmu->module))
10168 * A number of pmu->event_init() methods iterate the sibling_list to,
10169 * for example, validate if the group fits on the PMU. Therefore,
10170 * if this is a sibling event, acquire the ctx->mutex to protect
10171 * the sibling_list.
10173 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10175 * This ctx->mutex can nest when we're called through
10176 * inheritance. See the perf_event_ctx_lock_nested() comment.
10178 ctx = perf_event_ctx_lock_nested(event->group_leader,
10179 SINGLE_DEPTH_NESTING);
10184 ret = pmu->event_init(event);
10187 perf_event_ctx_unlock(event->group_leader, ctx);
10190 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10191 has_extended_regs(event))
10194 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10195 event_has_any_exclude_flag(event))
10198 if (ret && event->destroy)
10199 event->destroy(event);
10203 module_put(pmu->module);
10208 static struct pmu *perf_init_event(struct perf_event *event)
10214 idx = srcu_read_lock(&pmus_srcu);
10216 /* Try parent's PMU first: */
10217 if (event->parent && event->parent->pmu) {
10218 pmu = event->parent->pmu;
10219 ret = perf_try_init_event(pmu, event);
10225 pmu = idr_find(&pmu_idr, event->attr.type);
10228 ret = perf_try_init_event(pmu, event);
10230 pmu = ERR_PTR(ret);
10234 list_for_each_entry_rcu(pmu, &pmus, entry) {
10235 ret = perf_try_init_event(pmu, event);
10239 if (ret != -ENOENT) {
10240 pmu = ERR_PTR(ret);
10244 pmu = ERR_PTR(-ENOENT);
10246 srcu_read_unlock(&pmus_srcu, idx);
10251 static void attach_sb_event(struct perf_event *event)
10253 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10255 raw_spin_lock(&pel->lock);
10256 list_add_rcu(&event->sb_list, &pel->list);
10257 raw_spin_unlock(&pel->lock);
10261 * We keep a list of all !task (and therefore per-cpu) events
10262 * that need to receive side-band records.
10264 * This avoids having to scan all the various PMU per-cpu contexts
10265 * looking for them.
10267 static void account_pmu_sb_event(struct perf_event *event)
10269 if (is_sb_event(event))
10270 attach_sb_event(event);
10273 static void account_event_cpu(struct perf_event *event, int cpu)
10278 if (is_cgroup_event(event))
10279 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10282 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10283 static void account_freq_event_nohz(void)
10285 #ifdef CONFIG_NO_HZ_FULL
10286 /* Lock so we don't race with concurrent unaccount */
10287 spin_lock(&nr_freq_lock);
10288 if (atomic_inc_return(&nr_freq_events) == 1)
10289 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10290 spin_unlock(&nr_freq_lock);
10294 static void account_freq_event(void)
10296 if (tick_nohz_full_enabled())
10297 account_freq_event_nohz();
10299 atomic_inc(&nr_freq_events);
10303 static void account_event(struct perf_event *event)
10310 if (event->attach_state & PERF_ATTACH_TASK)
10312 if (event->attr.mmap || event->attr.mmap_data)
10313 atomic_inc(&nr_mmap_events);
10314 if (event->attr.comm)
10315 atomic_inc(&nr_comm_events);
10316 if (event->attr.namespaces)
10317 atomic_inc(&nr_namespaces_events);
10318 if (event->attr.task)
10319 atomic_inc(&nr_task_events);
10320 if (event->attr.freq)
10321 account_freq_event();
10322 if (event->attr.context_switch) {
10323 atomic_inc(&nr_switch_events);
10326 if (has_branch_stack(event))
10328 if (is_cgroup_event(event))
10330 if (event->attr.ksymbol)
10331 atomic_inc(&nr_ksymbol_events);
10332 if (event->attr.bpf_event)
10333 atomic_inc(&nr_bpf_events);
10337 * We need the mutex here because static_branch_enable()
10338 * must complete *before* the perf_sched_count increment
10341 if (atomic_inc_not_zero(&perf_sched_count))
10344 mutex_lock(&perf_sched_mutex);
10345 if (!atomic_read(&perf_sched_count)) {
10346 static_branch_enable(&perf_sched_events);
10348 * Guarantee that all CPUs observe they key change and
10349 * call the perf scheduling hooks before proceeding to
10350 * install events that need them.
10355 * Now that we have waited for the sync_sched(), allow further
10356 * increments to by-pass the mutex.
10358 atomic_inc(&perf_sched_count);
10359 mutex_unlock(&perf_sched_mutex);
10363 account_event_cpu(event, event->cpu);
10365 account_pmu_sb_event(event);
10369 * Allocate and initialize an event structure
10371 static struct perf_event *
10372 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10373 struct task_struct *task,
10374 struct perf_event *group_leader,
10375 struct perf_event *parent_event,
10376 perf_overflow_handler_t overflow_handler,
10377 void *context, int cgroup_fd)
10380 struct perf_event *event;
10381 struct hw_perf_event *hwc;
10382 long err = -EINVAL;
10384 if ((unsigned)cpu >= nr_cpu_ids) {
10385 if (!task || cpu != -1)
10386 return ERR_PTR(-EINVAL);
10389 event = kzalloc(sizeof(*event), GFP_KERNEL);
10391 return ERR_PTR(-ENOMEM);
10394 * Single events are their own group leaders, with an
10395 * empty sibling list:
10398 group_leader = event;
10400 mutex_init(&event->child_mutex);
10401 INIT_LIST_HEAD(&event->child_list);
10403 INIT_LIST_HEAD(&event->event_entry);
10404 INIT_LIST_HEAD(&event->sibling_list);
10405 INIT_LIST_HEAD(&event->active_list);
10406 init_event_group(event);
10407 INIT_LIST_HEAD(&event->rb_entry);
10408 INIT_LIST_HEAD(&event->active_entry);
10409 INIT_LIST_HEAD(&event->addr_filters.list);
10410 INIT_HLIST_NODE(&event->hlist_entry);
10413 init_waitqueue_head(&event->waitq);
10414 event->pending_disable = -1;
10415 init_irq_work(&event->pending, perf_pending_event);
10417 mutex_init(&event->mmap_mutex);
10418 raw_spin_lock_init(&event->addr_filters.lock);
10420 atomic_long_set(&event->refcount, 1);
10422 event->attr = *attr;
10423 event->group_leader = group_leader;
10427 event->parent = parent_event;
10429 event->ns = get_pid_ns(task_active_pid_ns(current));
10430 event->id = atomic64_inc_return(&perf_event_id);
10432 event->state = PERF_EVENT_STATE_INACTIVE;
10435 event->attach_state = PERF_ATTACH_TASK;
10437 * XXX pmu::event_init needs to know what task to account to
10438 * and we cannot use the ctx information because we need the
10439 * pmu before we get a ctx.
10441 event->hw.target = get_task_struct(task);
10444 event->clock = &local_clock;
10446 event->clock = parent_event->clock;
10448 if (!overflow_handler && parent_event) {
10449 overflow_handler = parent_event->overflow_handler;
10450 context = parent_event->overflow_handler_context;
10451 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10452 if (overflow_handler == bpf_overflow_handler) {
10453 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10455 if (IS_ERR(prog)) {
10456 err = PTR_ERR(prog);
10459 event->prog = prog;
10460 event->orig_overflow_handler =
10461 parent_event->orig_overflow_handler;
10466 if (overflow_handler) {
10467 event->overflow_handler = overflow_handler;
10468 event->overflow_handler_context = context;
10469 } else if (is_write_backward(event)){
10470 event->overflow_handler = perf_event_output_backward;
10471 event->overflow_handler_context = NULL;
10473 event->overflow_handler = perf_event_output_forward;
10474 event->overflow_handler_context = NULL;
10477 perf_event__state_init(event);
10482 hwc->sample_period = attr->sample_period;
10483 if (attr->freq && attr->sample_freq)
10484 hwc->sample_period = 1;
10485 hwc->last_period = hwc->sample_period;
10487 local64_set(&hwc->period_left, hwc->sample_period);
10490 * We currently do not support PERF_SAMPLE_READ on inherited events.
10491 * See perf_output_read().
10493 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10496 if (!has_branch_stack(event))
10497 event->attr.branch_sample_type = 0;
10499 if (cgroup_fd != -1) {
10500 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10505 pmu = perf_init_event(event);
10507 err = PTR_ERR(pmu);
10511 if (event->attr.aux_output &&
10512 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10517 err = exclusive_event_init(event);
10521 if (has_addr_filter(event)) {
10522 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10523 sizeof(struct perf_addr_filter_range),
10525 if (!event->addr_filter_ranges) {
10531 * Clone the parent's vma offsets: they are valid until exec()
10532 * even if the mm is not shared with the parent.
10534 if (event->parent) {
10535 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10537 raw_spin_lock_irq(&ifh->lock);
10538 memcpy(event->addr_filter_ranges,
10539 event->parent->addr_filter_ranges,
10540 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10541 raw_spin_unlock_irq(&ifh->lock);
10544 /* force hw sync on the address filters */
10545 event->addr_filters_gen = 1;
10548 if (!event->parent) {
10549 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10550 err = get_callchain_buffers(attr->sample_max_stack);
10552 goto err_addr_filters;
10556 /* symmetric to unaccount_event() in _free_event() */
10557 account_event(event);
10562 kfree(event->addr_filter_ranges);
10565 exclusive_event_destroy(event);
10568 if (event->destroy)
10569 event->destroy(event);
10570 module_put(pmu->module);
10572 if (is_cgroup_event(event))
10573 perf_detach_cgroup(event);
10575 put_pid_ns(event->ns);
10576 if (event->hw.target)
10577 put_task_struct(event->hw.target);
10580 return ERR_PTR(err);
10583 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10584 struct perf_event_attr *attr)
10589 if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
10593 * zero the full structure, so that a short copy will be nice.
10595 memset(attr, 0, sizeof(*attr));
10597 ret = get_user(size, &uattr->size);
10601 if (size > PAGE_SIZE) /* silly large */
10604 if (!size) /* abi compat */
10605 size = PERF_ATTR_SIZE_VER0;
10607 if (size < PERF_ATTR_SIZE_VER0)
10611 * If we're handed a bigger struct than we know of,
10612 * ensure all the unknown bits are 0 - i.e. new
10613 * user-space does not rely on any kernel feature
10614 * extensions we dont know about yet.
10616 if (size > sizeof(*attr)) {
10617 unsigned char __user *addr;
10618 unsigned char __user *end;
10621 addr = (void __user *)uattr + sizeof(*attr);
10622 end = (void __user *)uattr + size;
10624 for (; addr < end; addr++) {
10625 ret = get_user(val, addr);
10631 size = sizeof(*attr);
10634 ret = copy_from_user(attr, uattr, size);
10640 if (attr->__reserved_1)
10643 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10646 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10649 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10650 u64 mask = attr->branch_sample_type;
10652 /* only using defined bits */
10653 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10656 /* at least one branch bit must be set */
10657 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10660 /* propagate priv level, when not set for branch */
10661 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10663 /* exclude_kernel checked on syscall entry */
10664 if (!attr->exclude_kernel)
10665 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10667 if (!attr->exclude_user)
10668 mask |= PERF_SAMPLE_BRANCH_USER;
10670 if (!attr->exclude_hv)
10671 mask |= PERF_SAMPLE_BRANCH_HV;
10673 * adjust user setting (for HW filter setup)
10675 attr->branch_sample_type = mask;
10677 /* privileged levels capture (kernel, hv): check permissions */
10678 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10679 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10683 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10684 ret = perf_reg_validate(attr->sample_regs_user);
10689 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10690 if (!arch_perf_have_user_stack_dump())
10694 * We have __u32 type for the size, but so far
10695 * we can only use __u16 as maximum due to the
10696 * __u16 sample size limit.
10698 if (attr->sample_stack_user >= USHRT_MAX)
10700 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10704 if (!attr->sample_max_stack)
10705 attr->sample_max_stack = sysctl_perf_event_max_stack;
10707 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10708 ret = perf_reg_validate(attr->sample_regs_intr);
10713 put_user(sizeof(*attr), &uattr->size);
10719 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10721 struct ring_buffer *rb = NULL;
10727 /* don't allow circular references */
10728 if (event == output_event)
10732 * Don't allow cross-cpu buffers
10734 if (output_event->cpu != event->cpu)
10738 * If its not a per-cpu rb, it must be the same task.
10740 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10744 * Mixing clocks in the same buffer is trouble you don't need.
10746 if (output_event->clock != event->clock)
10750 * Either writing ring buffer from beginning or from end.
10751 * Mixing is not allowed.
10753 if (is_write_backward(output_event) != is_write_backward(event))
10757 * If both events generate aux data, they must be on the same PMU
10759 if (has_aux(event) && has_aux(output_event) &&
10760 event->pmu != output_event->pmu)
10764 mutex_lock(&event->mmap_mutex);
10765 /* Can't redirect output if we've got an active mmap() */
10766 if (atomic_read(&event->mmap_count))
10769 if (output_event) {
10770 /* get the rb we want to redirect to */
10771 rb = ring_buffer_get(output_event);
10776 ring_buffer_attach(event, rb);
10780 mutex_unlock(&event->mmap_mutex);
10786 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10792 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10795 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10797 bool nmi_safe = false;
10800 case CLOCK_MONOTONIC:
10801 event->clock = &ktime_get_mono_fast_ns;
10805 case CLOCK_MONOTONIC_RAW:
10806 event->clock = &ktime_get_raw_fast_ns;
10810 case CLOCK_REALTIME:
10811 event->clock = &ktime_get_real_ns;
10814 case CLOCK_BOOTTIME:
10815 event->clock = &ktime_get_boottime_ns;
10819 event->clock = &ktime_get_clocktai_ns;
10826 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10833 * Variation on perf_event_ctx_lock_nested(), except we take two context
10836 static struct perf_event_context *
10837 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10838 struct perf_event_context *ctx)
10840 struct perf_event_context *gctx;
10844 gctx = READ_ONCE(group_leader->ctx);
10845 if (!refcount_inc_not_zero(&gctx->refcount)) {
10851 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10853 if (group_leader->ctx != gctx) {
10854 mutex_unlock(&ctx->mutex);
10855 mutex_unlock(&gctx->mutex);
10864 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10866 * @attr_uptr: event_id type attributes for monitoring/sampling
10869 * @group_fd: group leader event fd
10871 SYSCALL_DEFINE5(perf_event_open,
10872 struct perf_event_attr __user *, attr_uptr,
10873 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10875 struct perf_event *group_leader = NULL, *output_event = NULL;
10876 struct perf_event *event, *sibling;
10877 struct perf_event_attr attr;
10878 struct perf_event_context *ctx, *uninitialized_var(gctx);
10879 struct file *event_file = NULL;
10880 struct fd group = {NULL, 0};
10881 struct task_struct *task = NULL;
10884 int move_group = 0;
10886 int f_flags = O_RDWR;
10887 int cgroup_fd = -1;
10889 /* for future expandability... */
10890 if (flags & ~PERF_FLAG_ALL)
10893 err = perf_copy_attr(attr_uptr, &attr);
10897 if (!attr.exclude_kernel) {
10898 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10902 if (attr.namespaces) {
10903 if (!capable(CAP_SYS_ADMIN))
10908 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10911 if (attr.sample_period & (1ULL << 63))
10915 /* Only privileged users can get physical addresses */
10916 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10917 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10920 err = security_locked_down(LOCKDOWN_PERF);
10921 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
10922 /* REGS_INTR can leak data, lockdown must prevent this */
10928 * In cgroup mode, the pid argument is used to pass the fd
10929 * opened to the cgroup directory in cgroupfs. The cpu argument
10930 * designates the cpu on which to monitor threads from that
10933 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10936 if (flags & PERF_FLAG_FD_CLOEXEC)
10937 f_flags |= O_CLOEXEC;
10939 event_fd = get_unused_fd_flags(f_flags);
10943 if (group_fd != -1) {
10944 err = perf_fget_light(group_fd, &group);
10947 group_leader = group.file->private_data;
10948 if (flags & PERF_FLAG_FD_OUTPUT)
10949 output_event = group_leader;
10950 if (flags & PERF_FLAG_FD_NO_GROUP)
10951 group_leader = NULL;
10954 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10955 task = find_lively_task_by_vpid(pid);
10956 if (IS_ERR(task)) {
10957 err = PTR_ERR(task);
10962 if (task && group_leader &&
10963 group_leader->attr.inherit != attr.inherit) {
10969 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10974 * Reuse ptrace permission checks for now.
10976 * We must hold cred_guard_mutex across this and any potential
10977 * perf_install_in_context() call for this new event to
10978 * serialize against exec() altering our credentials (and the
10979 * perf_event_exit_task() that could imply).
10982 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10986 if (flags & PERF_FLAG_PID_CGROUP)
10989 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10990 NULL, NULL, cgroup_fd);
10991 if (IS_ERR(event)) {
10992 err = PTR_ERR(event);
10996 if (is_sampling_event(event)) {
10997 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11004 * Special case software events and allow them to be part of
11005 * any hardware group.
11009 if (attr.use_clockid) {
11010 err = perf_event_set_clock(event, attr.clockid);
11015 if (pmu->task_ctx_nr == perf_sw_context)
11016 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11018 if (group_leader) {
11019 if (is_software_event(event) &&
11020 !in_software_context(group_leader)) {
11022 * If the event is a sw event, but the group_leader
11023 * is on hw context.
11025 * Allow the addition of software events to hw
11026 * groups, this is safe because software events
11027 * never fail to schedule.
11029 pmu = group_leader->ctx->pmu;
11030 } else if (!is_software_event(event) &&
11031 is_software_event(group_leader) &&
11032 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11034 * In case the group is a pure software group, and we
11035 * try to add a hardware event, move the whole group to
11036 * the hardware context.
11043 * Get the target context (task or percpu):
11045 ctx = find_get_context(pmu, task, event);
11047 err = PTR_ERR(ctx);
11052 * Look up the group leader (we will attach this event to it):
11054 if (group_leader) {
11058 * Do not allow a recursive hierarchy (this new sibling
11059 * becoming part of another group-sibling):
11061 if (group_leader->group_leader != group_leader)
11064 /* All events in a group should have the same clock */
11065 if (group_leader->clock != event->clock)
11069 * Make sure we're both events for the same CPU;
11070 * grouping events for different CPUs is broken; since
11071 * you can never concurrently schedule them anyhow.
11073 if (group_leader->cpu != event->cpu)
11077 * Make sure we're both on the same task, or both
11080 if (group_leader->ctx->task != ctx->task)
11084 * Do not allow to attach to a group in a different task
11085 * or CPU context. If we're moving SW events, we'll fix
11086 * this up later, so allow that.
11088 if (!move_group && group_leader->ctx != ctx)
11092 * Only a group leader can be exclusive or pinned
11094 if (attr.exclusive || attr.pinned)
11098 if (output_event) {
11099 err = perf_event_set_output(event, output_event);
11104 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11106 if (IS_ERR(event_file)) {
11107 err = PTR_ERR(event_file);
11113 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11115 if (gctx->task == TASK_TOMBSTONE) {
11121 * Check if we raced against another sys_perf_event_open() call
11122 * moving the software group underneath us.
11124 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11126 * If someone moved the group out from under us, check
11127 * if this new event wound up on the same ctx, if so
11128 * its the regular !move_group case, otherwise fail.
11134 perf_event_ctx_unlock(group_leader, gctx);
11140 * Failure to create exclusive events returns -EBUSY.
11143 if (!exclusive_event_installable(group_leader, ctx))
11146 for_each_sibling_event(sibling, group_leader) {
11147 if (!exclusive_event_installable(sibling, ctx))
11151 mutex_lock(&ctx->mutex);
11154 if (ctx->task == TASK_TOMBSTONE) {
11159 if (!perf_event_validate_size(event)) {
11166 * Check if the @cpu we're creating an event for is online.
11168 * We use the perf_cpu_context::ctx::mutex to serialize against
11169 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11171 struct perf_cpu_context *cpuctx =
11172 container_of(ctx, struct perf_cpu_context, ctx);
11174 if (!cpuctx->online) {
11180 if (event->attr.aux_output && !perf_get_aux_event(event, group_leader))
11184 * Must be under the same ctx::mutex as perf_install_in_context(),
11185 * because we need to serialize with concurrent event creation.
11187 if (!exclusive_event_installable(event, ctx)) {
11192 WARN_ON_ONCE(ctx->parent_ctx);
11195 * This is the point on no return; we cannot fail hereafter. This is
11196 * where we start modifying current state.
11201 * See perf_event_ctx_lock() for comments on the details
11202 * of swizzling perf_event::ctx.
11204 perf_remove_from_context(group_leader, 0);
11207 for_each_sibling_event(sibling, group_leader) {
11208 perf_remove_from_context(sibling, 0);
11213 * Wait for everybody to stop referencing the events through
11214 * the old lists, before installing it on new lists.
11219 * Install the group siblings before the group leader.
11221 * Because a group leader will try and install the entire group
11222 * (through the sibling list, which is still in-tact), we can
11223 * end up with siblings installed in the wrong context.
11225 * By installing siblings first we NO-OP because they're not
11226 * reachable through the group lists.
11228 for_each_sibling_event(sibling, group_leader) {
11229 perf_event__state_init(sibling);
11230 perf_install_in_context(ctx, sibling, sibling->cpu);
11235 * Removing from the context ends up with disabled
11236 * event. What we want here is event in the initial
11237 * startup state, ready to be add into new context.
11239 perf_event__state_init(group_leader);
11240 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11245 * Precalculate sample_data sizes; do while holding ctx::mutex such
11246 * that we're serialized against further additions and before
11247 * perf_install_in_context() which is the point the event is active and
11248 * can use these values.
11250 perf_event__header_size(event);
11251 perf_event__id_header_size(event);
11253 event->owner = current;
11255 perf_install_in_context(ctx, event, event->cpu);
11256 perf_unpin_context(ctx);
11259 perf_event_ctx_unlock(group_leader, gctx);
11260 mutex_unlock(&ctx->mutex);
11263 mutex_unlock(&task->signal->cred_guard_mutex);
11264 put_task_struct(task);
11267 mutex_lock(¤t->perf_event_mutex);
11268 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11269 mutex_unlock(¤t->perf_event_mutex);
11272 * Drop the reference on the group_event after placing the
11273 * new event on the sibling_list. This ensures destruction
11274 * of the group leader will find the pointer to itself in
11275 * perf_group_detach().
11278 fd_install(event_fd, event_file);
11283 perf_event_ctx_unlock(group_leader, gctx);
11284 mutex_unlock(&ctx->mutex);
11288 perf_unpin_context(ctx);
11292 * If event_file is set, the fput() above will have called ->release()
11293 * and that will take care of freeing the event.
11299 mutex_unlock(&task->signal->cred_guard_mutex);
11302 put_task_struct(task);
11306 put_unused_fd(event_fd);
11311 * perf_event_create_kernel_counter
11313 * @attr: attributes of the counter to create
11314 * @cpu: cpu in which the counter is bound
11315 * @task: task to profile (NULL for percpu)
11317 struct perf_event *
11318 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11319 struct task_struct *task,
11320 perf_overflow_handler_t overflow_handler,
11323 struct perf_event_context *ctx;
11324 struct perf_event *event;
11328 * Get the target context (task or percpu):
11331 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11332 overflow_handler, context, -1);
11333 if (IS_ERR(event)) {
11334 err = PTR_ERR(event);
11338 /* Mark owner so we could distinguish it from user events. */
11339 event->owner = TASK_TOMBSTONE;
11341 ctx = find_get_context(event->pmu, task, event);
11343 err = PTR_ERR(ctx);
11347 WARN_ON_ONCE(ctx->parent_ctx);
11348 mutex_lock(&ctx->mutex);
11349 if (ctx->task == TASK_TOMBSTONE) {
11356 * Check if the @cpu we're creating an event for is online.
11358 * We use the perf_cpu_context::ctx::mutex to serialize against
11359 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11361 struct perf_cpu_context *cpuctx =
11362 container_of(ctx, struct perf_cpu_context, ctx);
11363 if (!cpuctx->online) {
11369 if (!exclusive_event_installable(event, ctx)) {
11374 perf_install_in_context(ctx, event, event->cpu);
11375 perf_unpin_context(ctx);
11376 mutex_unlock(&ctx->mutex);
11381 mutex_unlock(&ctx->mutex);
11382 perf_unpin_context(ctx);
11387 return ERR_PTR(err);
11389 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11391 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11393 struct perf_event_context *src_ctx;
11394 struct perf_event_context *dst_ctx;
11395 struct perf_event *event, *tmp;
11398 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11399 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11402 * See perf_event_ctx_lock() for comments on the details
11403 * of swizzling perf_event::ctx.
11405 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11406 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11408 perf_remove_from_context(event, 0);
11409 unaccount_event_cpu(event, src_cpu);
11411 list_add(&event->migrate_entry, &events);
11415 * Wait for the events to quiesce before re-instating them.
11420 * Re-instate events in 2 passes.
11422 * Skip over group leaders and only install siblings on this first
11423 * pass, siblings will not get enabled without a leader, however a
11424 * leader will enable its siblings, even if those are still on the old
11427 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11428 if (event->group_leader == event)
11431 list_del(&event->migrate_entry);
11432 if (event->state >= PERF_EVENT_STATE_OFF)
11433 event->state = PERF_EVENT_STATE_INACTIVE;
11434 account_event_cpu(event, dst_cpu);
11435 perf_install_in_context(dst_ctx, event, dst_cpu);
11440 * Once all the siblings are setup properly, install the group leaders
11443 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11444 list_del(&event->migrate_entry);
11445 if (event->state >= PERF_EVENT_STATE_OFF)
11446 event->state = PERF_EVENT_STATE_INACTIVE;
11447 account_event_cpu(event, dst_cpu);
11448 perf_install_in_context(dst_ctx, event, dst_cpu);
11451 mutex_unlock(&dst_ctx->mutex);
11452 mutex_unlock(&src_ctx->mutex);
11454 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11456 static void sync_child_event(struct perf_event *child_event,
11457 struct task_struct *child)
11459 struct perf_event *parent_event = child_event->parent;
11462 if (child_event->attr.inherit_stat)
11463 perf_event_read_event(child_event, child);
11465 child_val = perf_event_count(child_event);
11468 * Add back the child's count to the parent's count:
11470 atomic64_add(child_val, &parent_event->child_count);
11471 atomic64_add(child_event->total_time_enabled,
11472 &parent_event->child_total_time_enabled);
11473 atomic64_add(child_event->total_time_running,
11474 &parent_event->child_total_time_running);
11478 perf_event_exit_event(struct perf_event *child_event,
11479 struct perf_event_context *child_ctx,
11480 struct task_struct *child)
11482 struct perf_event *parent_event = child_event->parent;
11485 * Do not destroy the 'original' grouping; because of the context
11486 * switch optimization the original events could've ended up in a
11487 * random child task.
11489 * If we were to destroy the original group, all group related
11490 * operations would cease to function properly after this random
11493 * Do destroy all inherited groups, we don't care about those
11494 * and being thorough is better.
11496 raw_spin_lock_irq(&child_ctx->lock);
11497 WARN_ON_ONCE(child_ctx->is_active);
11500 perf_group_detach(child_event);
11501 list_del_event(child_event, child_ctx);
11502 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11503 raw_spin_unlock_irq(&child_ctx->lock);
11506 * Parent events are governed by their filedesc, retain them.
11508 if (!parent_event) {
11509 perf_event_wakeup(child_event);
11513 * Child events can be cleaned up.
11516 sync_child_event(child_event, child);
11519 * Remove this event from the parent's list
11521 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11522 mutex_lock(&parent_event->child_mutex);
11523 list_del_init(&child_event->child_list);
11524 mutex_unlock(&parent_event->child_mutex);
11527 * Kick perf_poll() for is_event_hup().
11529 perf_event_wakeup(parent_event);
11530 free_event(child_event);
11531 put_event(parent_event);
11534 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11536 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11537 struct perf_event *child_event, *next;
11539 WARN_ON_ONCE(child != current);
11541 child_ctx = perf_pin_task_context(child, ctxn);
11546 * In order to reduce the amount of tricky in ctx tear-down, we hold
11547 * ctx::mutex over the entire thing. This serializes against almost
11548 * everything that wants to access the ctx.
11550 * The exception is sys_perf_event_open() /
11551 * perf_event_create_kernel_count() which does find_get_context()
11552 * without ctx::mutex (it cannot because of the move_group double mutex
11553 * lock thing). See the comments in perf_install_in_context().
11555 mutex_lock(&child_ctx->mutex);
11558 * In a single ctx::lock section, de-schedule the events and detach the
11559 * context from the task such that we cannot ever get it scheduled back
11562 raw_spin_lock_irq(&child_ctx->lock);
11563 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11566 * Now that the context is inactive, destroy the task <-> ctx relation
11567 * and mark the context dead.
11569 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11570 put_ctx(child_ctx); /* cannot be last */
11571 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11572 put_task_struct(current); /* cannot be last */
11574 clone_ctx = unclone_ctx(child_ctx);
11575 raw_spin_unlock_irq(&child_ctx->lock);
11578 put_ctx(clone_ctx);
11581 * Report the task dead after unscheduling the events so that we
11582 * won't get any samples after PERF_RECORD_EXIT. We can however still
11583 * get a few PERF_RECORD_READ events.
11585 perf_event_task(child, child_ctx, 0);
11587 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11588 perf_event_exit_event(child_event, child_ctx, child);
11590 mutex_unlock(&child_ctx->mutex);
11592 put_ctx(child_ctx);
11596 * When a child task exits, feed back event values to parent events.
11598 * Can be called with cred_guard_mutex held when called from
11599 * install_exec_creds().
11601 void perf_event_exit_task(struct task_struct *child)
11603 struct perf_event *event, *tmp;
11606 mutex_lock(&child->perf_event_mutex);
11607 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11609 list_del_init(&event->owner_entry);
11612 * Ensure the list deletion is visible before we clear
11613 * the owner, closes a race against perf_release() where
11614 * we need to serialize on the owner->perf_event_mutex.
11616 smp_store_release(&event->owner, NULL);
11618 mutex_unlock(&child->perf_event_mutex);
11620 for_each_task_context_nr(ctxn)
11621 perf_event_exit_task_context(child, ctxn);
11624 * The perf_event_exit_task_context calls perf_event_task
11625 * with child's task_ctx, which generates EXIT events for
11626 * child contexts and sets child->perf_event_ctxp[] to NULL.
11627 * At this point we need to send EXIT events to cpu contexts.
11629 perf_event_task(child, NULL, 0);
11632 static void perf_free_event(struct perf_event *event,
11633 struct perf_event_context *ctx)
11635 struct perf_event *parent = event->parent;
11637 if (WARN_ON_ONCE(!parent))
11640 mutex_lock(&parent->child_mutex);
11641 list_del_init(&event->child_list);
11642 mutex_unlock(&parent->child_mutex);
11646 raw_spin_lock_irq(&ctx->lock);
11647 perf_group_detach(event);
11648 list_del_event(event, ctx);
11649 raw_spin_unlock_irq(&ctx->lock);
11654 * Free a context as created by inheritance by perf_event_init_task() below,
11655 * used by fork() in case of fail.
11657 * Even though the task has never lived, the context and events have been
11658 * exposed through the child_list, so we must take care tearing it all down.
11660 void perf_event_free_task(struct task_struct *task)
11662 struct perf_event_context *ctx;
11663 struct perf_event *event, *tmp;
11666 for_each_task_context_nr(ctxn) {
11667 ctx = task->perf_event_ctxp[ctxn];
11671 mutex_lock(&ctx->mutex);
11672 raw_spin_lock_irq(&ctx->lock);
11674 * Destroy the task <-> ctx relation and mark the context dead.
11676 * This is important because even though the task hasn't been
11677 * exposed yet the context has been (through child_list).
11679 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11680 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11681 put_task_struct(task); /* cannot be last */
11682 raw_spin_unlock_irq(&ctx->lock);
11684 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11685 perf_free_event(event, ctx);
11687 mutex_unlock(&ctx->mutex);
11690 * perf_event_release_kernel() could've stolen some of our
11691 * child events and still have them on its free_list. In that
11692 * case we must wait for these events to have been freed (in
11693 * particular all their references to this task must've been
11696 * Without this copy_process() will unconditionally free this
11697 * task (irrespective of its reference count) and
11698 * _free_event()'s put_task_struct(event->hw.target) will be a
11701 * Wait for all events to drop their context reference.
11703 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
11704 put_ctx(ctx); /* must be last */
11708 void perf_event_delayed_put(struct task_struct *task)
11712 for_each_task_context_nr(ctxn)
11713 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11716 struct file *perf_event_get(unsigned int fd)
11718 struct file *file = fget(fd);
11720 return ERR_PTR(-EBADF);
11722 if (file->f_op != &perf_fops) {
11724 return ERR_PTR(-EBADF);
11730 const struct perf_event *perf_get_event(struct file *file)
11732 if (file->f_op != &perf_fops)
11733 return ERR_PTR(-EINVAL);
11735 return file->private_data;
11738 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11741 return ERR_PTR(-EINVAL);
11743 return &event->attr;
11747 * Inherit an event from parent task to child task.
11750 * - valid pointer on success
11751 * - NULL for orphaned events
11752 * - IS_ERR() on error
11754 static struct perf_event *
11755 inherit_event(struct perf_event *parent_event,
11756 struct task_struct *parent,
11757 struct perf_event_context *parent_ctx,
11758 struct task_struct *child,
11759 struct perf_event *group_leader,
11760 struct perf_event_context *child_ctx)
11762 enum perf_event_state parent_state = parent_event->state;
11763 struct perf_event *child_event;
11764 unsigned long flags;
11767 * Instead of creating recursive hierarchies of events,
11768 * we link inherited events back to the original parent,
11769 * which has a filp for sure, which we use as the reference
11772 if (parent_event->parent)
11773 parent_event = parent_event->parent;
11775 child_event = perf_event_alloc(&parent_event->attr,
11778 group_leader, parent_event,
11780 if (IS_ERR(child_event))
11781 return child_event;
11784 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11785 !child_ctx->task_ctx_data) {
11786 struct pmu *pmu = child_event->pmu;
11788 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11790 if (!child_ctx->task_ctx_data) {
11791 free_event(child_event);
11797 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11798 * must be under the same lock in order to serialize against
11799 * perf_event_release_kernel(), such that either we must observe
11800 * is_orphaned_event() or they will observe us on the child_list.
11802 mutex_lock(&parent_event->child_mutex);
11803 if (is_orphaned_event(parent_event) ||
11804 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11805 mutex_unlock(&parent_event->child_mutex);
11806 /* task_ctx_data is freed with child_ctx */
11807 free_event(child_event);
11811 get_ctx(child_ctx);
11814 * Make the child state follow the state of the parent event,
11815 * not its attr.disabled bit. We hold the parent's mutex,
11816 * so we won't race with perf_event_{en, dis}able_family.
11818 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11819 child_event->state = PERF_EVENT_STATE_INACTIVE;
11821 child_event->state = PERF_EVENT_STATE_OFF;
11823 if (parent_event->attr.freq) {
11824 u64 sample_period = parent_event->hw.sample_period;
11825 struct hw_perf_event *hwc = &child_event->hw;
11827 hwc->sample_period = sample_period;
11828 hwc->last_period = sample_period;
11830 local64_set(&hwc->period_left, sample_period);
11833 child_event->ctx = child_ctx;
11834 child_event->overflow_handler = parent_event->overflow_handler;
11835 child_event->overflow_handler_context
11836 = parent_event->overflow_handler_context;
11839 * Precalculate sample_data sizes
11841 perf_event__header_size(child_event);
11842 perf_event__id_header_size(child_event);
11845 * Link it up in the child's context:
11847 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11848 add_event_to_ctx(child_event, child_ctx);
11849 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11852 * Link this into the parent event's child list
11854 list_add_tail(&child_event->child_list, &parent_event->child_list);
11855 mutex_unlock(&parent_event->child_mutex);
11857 return child_event;
11861 * Inherits an event group.
11863 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11864 * This matches with perf_event_release_kernel() removing all child events.
11870 static int inherit_group(struct perf_event *parent_event,
11871 struct task_struct *parent,
11872 struct perf_event_context *parent_ctx,
11873 struct task_struct *child,
11874 struct perf_event_context *child_ctx)
11876 struct perf_event *leader;
11877 struct perf_event *sub;
11878 struct perf_event *child_ctr;
11880 leader = inherit_event(parent_event, parent, parent_ctx,
11881 child, NULL, child_ctx);
11882 if (IS_ERR(leader))
11883 return PTR_ERR(leader);
11885 * @leader can be NULL here because of is_orphaned_event(). In this
11886 * case inherit_event() will create individual events, similar to what
11887 * perf_group_detach() would do anyway.
11889 for_each_sibling_event(sub, parent_event) {
11890 child_ctr = inherit_event(sub, parent, parent_ctx,
11891 child, leader, child_ctx);
11892 if (IS_ERR(child_ctr))
11893 return PTR_ERR(child_ctr);
11899 * Creates the child task context and tries to inherit the event-group.
11901 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11902 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11903 * consistent with perf_event_release_kernel() removing all child events.
11910 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11911 struct perf_event_context *parent_ctx,
11912 struct task_struct *child, int ctxn,
11913 int *inherited_all)
11916 struct perf_event_context *child_ctx;
11918 if (!event->attr.inherit) {
11919 *inherited_all = 0;
11923 child_ctx = child->perf_event_ctxp[ctxn];
11926 * This is executed from the parent task context, so
11927 * inherit events that have been marked for cloning.
11928 * First allocate and initialize a context for the
11931 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11935 child->perf_event_ctxp[ctxn] = child_ctx;
11938 ret = inherit_group(event, parent, parent_ctx,
11942 *inherited_all = 0;
11948 * Initialize the perf_event context in task_struct
11950 static int perf_event_init_context(struct task_struct *child, int ctxn)
11952 struct perf_event_context *child_ctx, *parent_ctx;
11953 struct perf_event_context *cloned_ctx;
11954 struct perf_event *event;
11955 struct task_struct *parent = current;
11956 int inherited_all = 1;
11957 unsigned long flags;
11960 if (likely(!parent->perf_event_ctxp[ctxn]))
11964 * If the parent's context is a clone, pin it so it won't get
11965 * swapped under us.
11967 parent_ctx = perf_pin_task_context(parent, ctxn);
11972 * No need to check if parent_ctx != NULL here; since we saw
11973 * it non-NULL earlier, the only reason for it to become NULL
11974 * is if we exit, and since we're currently in the middle of
11975 * a fork we can't be exiting at the same time.
11979 * Lock the parent list. No need to lock the child - not PID
11980 * hashed yet and not running, so nobody can access it.
11982 mutex_lock(&parent_ctx->mutex);
11985 * We dont have to disable NMIs - we are only looking at
11986 * the list, not manipulating it:
11988 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11989 ret = inherit_task_group(event, parent, parent_ctx,
11990 child, ctxn, &inherited_all);
11996 * We can't hold ctx->lock when iterating the ->flexible_group list due
11997 * to allocations, but we need to prevent rotation because
11998 * rotate_ctx() will change the list from interrupt context.
12000 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12001 parent_ctx->rotate_disable = 1;
12002 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12004 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12005 ret = inherit_task_group(event, parent, parent_ctx,
12006 child, ctxn, &inherited_all);
12011 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12012 parent_ctx->rotate_disable = 0;
12014 child_ctx = child->perf_event_ctxp[ctxn];
12016 if (child_ctx && inherited_all) {
12018 * Mark the child context as a clone of the parent
12019 * context, or of whatever the parent is a clone of.
12021 * Note that if the parent is a clone, the holding of
12022 * parent_ctx->lock avoids it from being uncloned.
12024 cloned_ctx = parent_ctx->parent_ctx;
12026 child_ctx->parent_ctx = cloned_ctx;
12027 child_ctx->parent_gen = parent_ctx->parent_gen;
12029 child_ctx->parent_ctx = parent_ctx;
12030 child_ctx->parent_gen = parent_ctx->generation;
12032 get_ctx(child_ctx->parent_ctx);
12035 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12037 mutex_unlock(&parent_ctx->mutex);
12039 perf_unpin_context(parent_ctx);
12040 put_ctx(parent_ctx);
12046 * Initialize the perf_event context in task_struct
12048 int perf_event_init_task(struct task_struct *child)
12052 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12053 mutex_init(&child->perf_event_mutex);
12054 INIT_LIST_HEAD(&child->perf_event_list);
12056 for_each_task_context_nr(ctxn) {
12057 ret = perf_event_init_context(child, ctxn);
12059 perf_event_free_task(child);
12067 static void __init perf_event_init_all_cpus(void)
12069 struct swevent_htable *swhash;
12072 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12074 for_each_possible_cpu(cpu) {
12075 swhash = &per_cpu(swevent_htable, cpu);
12076 mutex_init(&swhash->hlist_mutex);
12077 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12079 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12080 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12082 #ifdef CONFIG_CGROUP_PERF
12083 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12085 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12089 static void perf_swevent_init_cpu(unsigned int cpu)
12091 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12093 mutex_lock(&swhash->hlist_mutex);
12094 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12095 struct swevent_hlist *hlist;
12097 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12099 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12101 mutex_unlock(&swhash->hlist_mutex);
12104 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12105 static void __perf_event_exit_context(void *__info)
12107 struct perf_event_context *ctx = __info;
12108 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12109 struct perf_event *event;
12111 raw_spin_lock(&ctx->lock);
12112 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12113 list_for_each_entry(event, &ctx->event_list, event_entry)
12114 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12115 raw_spin_unlock(&ctx->lock);
12118 static void perf_event_exit_cpu_context(int cpu)
12120 struct perf_cpu_context *cpuctx;
12121 struct perf_event_context *ctx;
12124 mutex_lock(&pmus_lock);
12125 list_for_each_entry(pmu, &pmus, entry) {
12126 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12127 ctx = &cpuctx->ctx;
12129 mutex_lock(&ctx->mutex);
12130 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12131 cpuctx->online = 0;
12132 mutex_unlock(&ctx->mutex);
12134 cpumask_clear_cpu(cpu, perf_online_mask);
12135 mutex_unlock(&pmus_lock);
12139 static void perf_event_exit_cpu_context(int cpu) { }
12143 int perf_event_init_cpu(unsigned int cpu)
12145 struct perf_cpu_context *cpuctx;
12146 struct perf_event_context *ctx;
12149 perf_swevent_init_cpu(cpu);
12151 mutex_lock(&pmus_lock);
12152 cpumask_set_cpu(cpu, perf_online_mask);
12153 list_for_each_entry(pmu, &pmus, entry) {
12154 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12155 ctx = &cpuctx->ctx;
12157 mutex_lock(&ctx->mutex);
12158 cpuctx->online = 1;
12159 mutex_unlock(&ctx->mutex);
12161 mutex_unlock(&pmus_lock);
12166 int perf_event_exit_cpu(unsigned int cpu)
12168 perf_event_exit_cpu_context(cpu);
12173 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12177 for_each_online_cpu(cpu)
12178 perf_event_exit_cpu(cpu);
12184 * Run the perf reboot notifier at the very last possible moment so that
12185 * the generic watchdog code runs as long as possible.
12187 static struct notifier_block perf_reboot_notifier = {
12188 .notifier_call = perf_reboot,
12189 .priority = INT_MIN,
12192 void __init perf_event_init(void)
12196 idr_init(&pmu_idr);
12198 perf_event_init_all_cpus();
12199 init_srcu_struct(&pmus_srcu);
12200 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12201 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12202 perf_pmu_register(&perf_task_clock, NULL, -1);
12203 perf_tp_register();
12204 perf_event_init_cpu(smp_processor_id());
12205 register_reboot_notifier(&perf_reboot_notifier);
12207 ret = init_hw_breakpoint();
12208 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12211 * Build time assertion that we keep the data_head at the intended
12212 * location. IOW, validation we got the __reserved[] size right.
12214 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12218 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12221 struct perf_pmu_events_attr *pmu_attr =
12222 container_of(attr, struct perf_pmu_events_attr, attr);
12224 if (pmu_attr->event_str)
12225 return sprintf(page, "%s\n", pmu_attr->event_str);
12229 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12231 static int __init perf_event_sysfs_init(void)
12236 mutex_lock(&pmus_lock);
12238 ret = bus_register(&pmu_bus);
12242 list_for_each_entry(pmu, &pmus, entry) {
12243 if (!pmu->name || pmu->type < 0)
12246 ret = pmu_dev_alloc(pmu);
12247 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12249 pmu_bus_running = 1;
12253 mutex_unlock(&pmus_lock);
12257 device_initcall(perf_event_sysfs_init);
12259 #ifdef CONFIG_CGROUP_PERF
12260 static struct cgroup_subsys_state *
12261 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12263 struct perf_cgroup *jc;
12265 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12267 return ERR_PTR(-ENOMEM);
12269 jc->info = alloc_percpu(struct perf_cgroup_info);
12272 return ERR_PTR(-ENOMEM);
12278 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12280 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12282 free_percpu(jc->info);
12286 static int __perf_cgroup_move(void *info)
12288 struct task_struct *task = info;
12290 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12295 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12297 struct task_struct *task;
12298 struct cgroup_subsys_state *css;
12300 cgroup_taskset_for_each(task, css, tset)
12301 task_function_call(task, __perf_cgroup_move, task);
12304 struct cgroup_subsys perf_event_cgrp_subsys = {
12305 .css_alloc = perf_cgroup_css_alloc,
12306 .css_free = perf_cgroup_css_free,
12307 .attach = perf_cgroup_attach,
12309 * Implicitly enable on dfl hierarchy so that perf events can
12310 * always be filtered by cgroup2 path as long as perf_event
12311 * controller is not mounted on a legacy hierarchy.
12313 .implicit_on_dfl = true,
12316 #endif /* CONFIG_CGROUP_PERF */