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 /* pick an event from the flexible_groups to rotate */
3783 static inline struct perf_event *
3784 ctx_event_to_rotate(struct perf_event_context *ctx)
3786 struct perf_event *event;
3788 /* pick the first active flexible event */
3789 event = list_first_entry_or_null(&ctx->flexible_active,
3790 struct perf_event, active_list);
3792 /* if no active flexible event, pick the first event */
3794 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3795 typeof(*event), group_node);
3801 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3803 struct perf_event *cpu_event = NULL, *task_event = NULL;
3804 struct perf_event_context *task_ctx = NULL;
3805 int cpu_rotate, task_rotate;
3808 * Since we run this from IRQ context, nobody can install new
3809 * events, thus the event count values are stable.
3812 cpu_rotate = cpuctx->ctx.rotate_necessary;
3813 task_ctx = cpuctx->task_ctx;
3814 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3816 if (!(cpu_rotate || task_rotate))
3819 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3820 perf_pmu_disable(cpuctx->ctx.pmu);
3823 task_event = ctx_event_to_rotate(task_ctx);
3825 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3828 * As per the order given at ctx_resched() first 'pop' task flexible
3829 * and then, if needed CPU flexible.
3831 if (task_event || (task_ctx && cpu_event))
3832 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3834 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3837 rotate_ctx(task_ctx, task_event);
3839 rotate_ctx(&cpuctx->ctx, cpu_event);
3841 perf_event_sched_in(cpuctx, task_ctx, current);
3843 perf_pmu_enable(cpuctx->ctx.pmu);
3844 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3849 void perf_event_task_tick(void)
3851 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3852 struct perf_event_context *ctx, *tmp;
3855 lockdep_assert_irqs_disabled();
3857 __this_cpu_inc(perf_throttled_seq);
3858 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3859 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3861 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3862 perf_adjust_freq_unthr_context(ctx, throttled);
3865 static int event_enable_on_exec(struct perf_event *event,
3866 struct perf_event_context *ctx)
3868 if (!event->attr.enable_on_exec)
3871 event->attr.enable_on_exec = 0;
3872 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3875 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3881 * Enable all of a task's events that have been marked enable-on-exec.
3882 * This expects task == current.
3884 static void perf_event_enable_on_exec(int ctxn)
3886 struct perf_event_context *ctx, *clone_ctx = NULL;
3887 enum event_type_t event_type = 0;
3888 struct perf_cpu_context *cpuctx;
3889 struct perf_event *event;
3890 unsigned long flags;
3893 local_irq_save(flags);
3894 ctx = current->perf_event_ctxp[ctxn];
3895 if (!ctx || !ctx->nr_events)
3898 cpuctx = __get_cpu_context(ctx);
3899 perf_ctx_lock(cpuctx, ctx);
3900 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3901 list_for_each_entry(event, &ctx->event_list, event_entry) {
3902 enabled |= event_enable_on_exec(event, ctx);
3903 event_type |= get_event_type(event);
3907 * Unclone and reschedule this context if we enabled any event.
3910 clone_ctx = unclone_ctx(ctx);
3911 ctx_resched(cpuctx, ctx, event_type);
3913 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3915 perf_ctx_unlock(cpuctx, ctx);
3918 local_irq_restore(flags);
3924 struct perf_read_data {
3925 struct perf_event *event;
3930 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3932 u16 local_pkg, event_pkg;
3934 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3935 int local_cpu = smp_processor_id();
3937 event_pkg = topology_physical_package_id(event_cpu);
3938 local_pkg = topology_physical_package_id(local_cpu);
3940 if (event_pkg == local_pkg)
3948 * Cross CPU call to read the hardware event
3950 static void __perf_event_read(void *info)
3952 struct perf_read_data *data = info;
3953 struct perf_event *sub, *event = data->event;
3954 struct perf_event_context *ctx = event->ctx;
3955 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3956 struct pmu *pmu = event->pmu;
3959 * If this is a task context, we need to check whether it is
3960 * the current task context of this cpu. If not it has been
3961 * scheduled out before the smp call arrived. In that case
3962 * event->count would have been updated to a recent sample
3963 * when the event was scheduled out.
3965 if (ctx->task && cpuctx->task_ctx != ctx)
3968 raw_spin_lock(&ctx->lock);
3969 if (ctx->is_active & EVENT_TIME) {
3970 update_context_time(ctx);
3971 update_cgrp_time_from_event(event);
3974 perf_event_update_time(event);
3976 perf_event_update_sibling_time(event);
3978 if (event->state != PERF_EVENT_STATE_ACTIVE)
3987 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3991 for_each_sibling_event(sub, event) {
3992 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3994 * Use sibling's PMU rather than @event's since
3995 * sibling could be on different (eg: software) PMU.
3997 sub->pmu->read(sub);
4001 data->ret = pmu->commit_txn(pmu);
4004 raw_spin_unlock(&ctx->lock);
4007 static inline u64 perf_event_count(struct perf_event *event)
4009 return local64_read(&event->count) + atomic64_read(&event->child_count);
4013 * NMI-safe method to read a local event, that is an event that
4015 * - either for the current task, or for this CPU
4016 * - does not have inherit set, for inherited task events
4017 * will not be local and we cannot read them atomically
4018 * - must not have a pmu::count method
4020 int perf_event_read_local(struct perf_event *event, u64 *value,
4021 u64 *enabled, u64 *running)
4023 unsigned long flags;
4027 * Disabling interrupts avoids all counter scheduling (context
4028 * switches, timer based rotation and IPIs).
4030 local_irq_save(flags);
4033 * It must not be an event with inherit set, we cannot read
4034 * all child counters from atomic context.
4036 if (event->attr.inherit) {
4041 /* If this is a per-task event, it must be for current */
4042 if ((event->attach_state & PERF_ATTACH_TASK) &&
4043 event->hw.target != current) {
4048 /* If this is a per-CPU event, it must be for this CPU */
4049 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4050 event->cpu != smp_processor_id()) {
4055 /* If this is a pinned event it must be running on this CPU */
4056 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4062 * If the event is currently on this CPU, its either a per-task event,
4063 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4066 if (event->oncpu == smp_processor_id())
4067 event->pmu->read(event);
4069 *value = local64_read(&event->count);
4070 if (enabled || running) {
4071 u64 now = event->shadow_ctx_time + perf_clock();
4072 u64 __enabled, __running;
4074 __perf_update_times(event, now, &__enabled, &__running);
4076 *enabled = __enabled;
4078 *running = __running;
4081 local_irq_restore(flags);
4086 static int perf_event_read(struct perf_event *event, bool group)
4088 enum perf_event_state state = READ_ONCE(event->state);
4089 int event_cpu, ret = 0;
4092 * If event is enabled and currently active on a CPU, update the
4093 * value in the event structure:
4096 if (state == PERF_EVENT_STATE_ACTIVE) {
4097 struct perf_read_data data;
4100 * Orders the ->state and ->oncpu loads such that if we see
4101 * ACTIVE we must also see the right ->oncpu.
4103 * Matches the smp_wmb() from event_sched_in().
4107 event_cpu = READ_ONCE(event->oncpu);
4108 if ((unsigned)event_cpu >= nr_cpu_ids)
4111 data = (struct perf_read_data){
4118 event_cpu = __perf_event_read_cpu(event, event_cpu);
4121 * Purposely ignore the smp_call_function_single() return
4124 * If event_cpu isn't a valid CPU it means the event got
4125 * scheduled out and that will have updated the event count.
4127 * Therefore, either way, we'll have an up-to-date event count
4130 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4134 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4135 struct perf_event_context *ctx = event->ctx;
4136 unsigned long flags;
4138 raw_spin_lock_irqsave(&ctx->lock, flags);
4139 state = event->state;
4140 if (state != PERF_EVENT_STATE_INACTIVE) {
4141 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4146 * May read while context is not active (e.g., thread is
4147 * blocked), in that case we cannot update context time
4149 if (ctx->is_active & EVENT_TIME) {
4150 update_context_time(ctx);
4151 update_cgrp_time_from_event(event);
4154 perf_event_update_time(event);
4156 perf_event_update_sibling_time(event);
4157 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4164 * Initialize the perf_event context in a task_struct:
4166 static void __perf_event_init_context(struct perf_event_context *ctx)
4168 raw_spin_lock_init(&ctx->lock);
4169 mutex_init(&ctx->mutex);
4170 INIT_LIST_HEAD(&ctx->active_ctx_list);
4171 perf_event_groups_init(&ctx->pinned_groups);
4172 perf_event_groups_init(&ctx->flexible_groups);
4173 INIT_LIST_HEAD(&ctx->event_list);
4174 INIT_LIST_HEAD(&ctx->pinned_active);
4175 INIT_LIST_HEAD(&ctx->flexible_active);
4176 refcount_set(&ctx->refcount, 1);
4179 static struct perf_event_context *
4180 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4182 struct perf_event_context *ctx;
4184 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4188 __perf_event_init_context(ctx);
4190 ctx->task = get_task_struct(task);
4196 static struct task_struct *
4197 find_lively_task_by_vpid(pid_t vpid)
4199 struct task_struct *task;
4205 task = find_task_by_vpid(vpid);
4207 get_task_struct(task);
4211 return ERR_PTR(-ESRCH);
4217 * Returns a matching context with refcount and pincount.
4219 static struct perf_event_context *
4220 find_get_context(struct pmu *pmu, struct task_struct *task,
4221 struct perf_event *event)
4223 struct perf_event_context *ctx, *clone_ctx = NULL;
4224 struct perf_cpu_context *cpuctx;
4225 void *task_ctx_data = NULL;
4226 unsigned long flags;
4228 int cpu = event->cpu;
4231 /* Must be root to operate on a CPU event: */
4232 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4233 return ERR_PTR(-EACCES);
4235 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4244 ctxn = pmu->task_ctx_nr;
4248 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4249 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4250 if (!task_ctx_data) {
4257 ctx = perf_lock_task_context(task, ctxn, &flags);
4259 clone_ctx = unclone_ctx(ctx);
4262 if (task_ctx_data && !ctx->task_ctx_data) {
4263 ctx->task_ctx_data = task_ctx_data;
4264 task_ctx_data = NULL;
4266 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4271 ctx = alloc_perf_context(pmu, task);
4276 if (task_ctx_data) {
4277 ctx->task_ctx_data = task_ctx_data;
4278 task_ctx_data = NULL;
4282 mutex_lock(&task->perf_event_mutex);
4284 * If it has already passed perf_event_exit_task().
4285 * we must see PF_EXITING, it takes this mutex too.
4287 if (task->flags & PF_EXITING)
4289 else if (task->perf_event_ctxp[ctxn])
4294 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4296 mutex_unlock(&task->perf_event_mutex);
4298 if (unlikely(err)) {
4307 kfree(task_ctx_data);
4311 kfree(task_ctx_data);
4312 return ERR_PTR(err);
4315 static void perf_event_free_filter(struct perf_event *event);
4316 static void perf_event_free_bpf_prog(struct perf_event *event);
4318 static void free_event_rcu(struct rcu_head *head)
4320 struct perf_event *event;
4322 event = container_of(head, struct perf_event, rcu_head);
4324 put_pid_ns(event->ns);
4325 perf_event_free_filter(event);
4329 static void ring_buffer_attach(struct perf_event *event,
4330 struct ring_buffer *rb);
4332 static void detach_sb_event(struct perf_event *event)
4334 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4336 raw_spin_lock(&pel->lock);
4337 list_del_rcu(&event->sb_list);
4338 raw_spin_unlock(&pel->lock);
4341 static bool is_sb_event(struct perf_event *event)
4343 struct perf_event_attr *attr = &event->attr;
4348 if (event->attach_state & PERF_ATTACH_TASK)
4351 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4352 attr->comm || attr->comm_exec ||
4353 attr->task || attr->ksymbol ||
4354 attr->context_switch ||
4360 static void unaccount_pmu_sb_event(struct perf_event *event)
4362 if (is_sb_event(event))
4363 detach_sb_event(event);
4366 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4371 if (is_cgroup_event(event))
4372 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4375 #ifdef CONFIG_NO_HZ_FULL
4376 static DEFINE_SPINLOCK(nr_freq_lock);
4379 static void unaccount_freq_event_nohz(void)
4381 #ifdef CONFIG_NO_HZ_FULL
4382 spin_lock(&nr_freq_lock);
4383 if (atomic_dec_and_test(&nr_freq_events))
4384 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4385 spin_unlock(&nr_freq_lock);
4389 static void unaccount_freq_event(void)
4391 if (tick_nohz_full_enabled())
4392 unaccount_freq_event_nohz();
4394 atomic_dec(&nr_freq_events);
4397 static void unaccount_event(struct perf_event *event)
4404 if (event->attach_state & PERF_ATTACH_TASK)
4406 if (event->attr.mmap || event->attr.mmap_data)
4407 atomic_dec(&nr_mmap_events);
4408 if (event->attr.comm)
4409 atomic_dec(&nr_comm_events);
4410 if (event->attr.namespaces)
4411 atomic_dec(&nr_namespaces_events);
4412 if (event->attr.task)
4413 atomic_dec(&nr_task_events);
4414 if (event->attr.freq)
4415 unaccount_freq_event();
4416 if (event->attr.context_switch) {
4418 atomic_dec(&nr_switch_events);
4420 if (is_cgroup_event(event))
4422 if (has_branch_stack(event))
4424 if (event->attr.ksymbol)
4425 atomic_dec(&nr_ksymbol_events);
4426 if (event->attr.bpf_event)
4427 atomic_dec(&nr_bpf_events);
4430 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4431 schedule_delayed_work(&perf_sched_work, HZ);
4434 unaccount_event_cpu(event, event->cpu);
4436 unaccount_pmu_sb_event(event);
4439 static void perf_sched_delayed(struct work_struct *work)
4441 mutex_lock(&perf_sched_mutex);
4442 if (atomic_dec_and_test(&perf_sched_count))
4443 static_branch_disable(&perf_sched_events);
4444 mutex_unlock(&perf_sched_mutex);
4448 * The following implement mutual exclusion of events on "exclusive" pmus
4449 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4450 * at a time, so we disallow creating events that might conflict, namely:
4452 * 1) cpu-wide events in the presence of per-task events,
4453 * 2) per-task events in the presence of cpu-wide events,
4454 * 3) two matching events on the same context.
4456 * The former two cases are handled in the allocation path (perf_event_alloc(),
4457 * _free_event()), the latter -- before the first perf_install_in_context().
4459 static int exclusive_event_init(struct perf_event *event)
4461 struct pmu *pmu = event->pmu;
4463 if (!is_exclusive_pmu(pmu))
4467 * Prevent co-existence of per-task and cpu-wide events on the
4468 * same exclusive pmu.
4470 * Negative pmu::exclusive_cnt means there are cpu-wide
4471 * events on this "exclusive" pmu, positive means there are
4474 * Since this is called in perf_event_alloc() path, event::ctx
4475 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4476 * to mean "per-task event", because unlike other attach states it
4477 * never gets cleared.
4479 if (event->attach_state & PERF_ATTACH_TASK) {
4480 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4483 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4490 static void exclusive_event_destroy(struct perf_event *event)
4492 struct pmu *pmu = event->pmu;
4494 if (!is_exclusive_pmu(pmu))
4497 /* see comment in exclusive_event_init() */
4498 if (event->attach_state & PERF_ATTACH_TASK)
4499 atomic_dec(&pmu->exclusive_cnt);
4501 atomic_inc(&pmu->exclusive_cnt);
4504 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4506 if ((e1->pmu == e2->pmu) &&
4507 (e1->cpu == e2->cpu ||
4514 static bool exclusive_event_installable(struct perf_event *event,
4515 struct perf_event_context *ctx)
4517 struct perf_event *iter_event;
4518 struct pmu *pmu = event->pmu;
4520 lockdep_assert_held(&ctx->mutex);
4522 if (!is_exclusive_pmu(pmu))
4525 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4526 if (exclusive_event_match(iter_event, event))
4533 static void perf_addr_filters_splice(struct perf_event *event,
4534 struct list_head *head);
4536 static void _free_event(struct perf_event *event)
4538 irq_work_sync(&event->pending);
4540 unaccount_event(event);
4544 * Can happen when we close an event with re-directed output.
4546 * Since we have a 0 refcount, perf_mmap_close() will skip
4547 * over us; possibly making our ring_buffer_put() the last.
4549 mutex_lock(&event->mmap_mutex);
4550 ring_buffer_attach(event, NULL);
4551 mutex_unlock(&event->mmap_mutex);
4554 if (is_cgroup_event(event))
4555 perf_detach_cgroup(event);
4557 if (!event->parent) {
4558 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4559 put_callchain_buffers();
4562 perf_event_free_bpf_prog(event);
4563 perf_addr_filters_splice(event, NULL);
4564 kfree(event->addr_filter_ranges);
4567 event->destroy(event);
4570 * Must be after ->destroy(), due to uprobe_perf_close() using
4573 if (event->hw.target)
4574 put_task_struct(event->hw.target);
4577 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4578 * all task references must be cleaned up.
4581 put_ctx(event->ctx);
4583 exclusive_event_destroy(event);
4584 module_put(event->pmu->module);
4586 call_rcu(&event->rcu_head, free_event_rcu);
4590 * Used to free events which have a known refcount of 1, such as in error paths
4591 * where the event isn't exposed yet and inherited events.
4593 static void free_event(struct perf_event *event)
4595 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4596 "unexpected event refcount: %ld; ptr=%p\n",
4597 atomic_long_read(&event->refcount), event)) {
4598 /* leak to avoid use-after-free */
4606 * Remove user event from the owner task.
4608 static void perf_remove_from_owner(struct perf_event *event)
4610 struct task_struct *owner;
4614 * Matches the smp_store_release() in perf_event_exit_task(). If we
4615 * observe !owner it means the list deletion is complete and we can
4616 * indeed free this event, otherwise we need to serialize on
4617 * owner->perf_event_mutex.
4619 owner = READ_ONCE(event->owner);
4622 * Since delayed_put_task_struct() also drops the last
4623 * task reference we can safely take a new reference
4624 * while holding the rcu_read_lock().
4626 get_task_struct(owner);
4632 * If we're here through perf_event_exit_task() we're already
4633 * holding ctx->mutex which would be an inversion wrt. the
4634 * normal lock order.
4636 * However we can safely take this lock because its the child
4639 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4642 * We have to re-check the event->owner field, if it is cleared
4643 * we raced with perf_event_exit_task(), acquiring the mutex
4644 * ensured they're done, and we can proceed with freeing the
4648 list_del_init(&event->owner_entry);
4649 smp_store_release(&event->owner, NULL);
4651 mutex_unlock(&owner->perf_event_mutex);
4652 put_task_struct(owner);
4656 static void put_event(struct perf_event *event)
4658 if (!atomic_long_dec_and_test(&event->refcount))
4665 * Kill an event dead; while event:refcount will preserve the event
4666 * object, it will not preserve its functionality. Once the last 'user'
4667 * gives up the object, we'll destroy the thing.
4669 int perf_event_release_kernel(struct perf_event *event)
4671 struct perf_event_context *ctx = event->ctx;
4672 struct perf_event *child, *tmp;
4673 LIST_HEAD(free_list);
4676 * If we got here through err_file: fput(event_file); we will not have
4677 * attached to a context yet.
4680 WARN_ON_ONCE(event->attach_state &
4681 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4685 if (!is_kernel_event(event))
4686 perf_remove_from_owner(event);
4688 ctx = perf_event_ctx_lock(event);
4689 WARN_ON_ONCE(ctx->parent_ctx);
4690 perf_remove_from_context(event, DETACH_GROUP);
4692 raw_spin_lock_irq(&ctx->lock);
4694 * Mark this event as STATE_DEAD, there is no external reference to it
4697 * Anybody acquiring event->child_mutex after the below loop _must_
4698 * also see this, most importantly inherit_event() which will avoid
4699 * placing more children on the list.
4701 * Thus this guarantees that we will in fact observe and kill _ALL_
4704 event->state = PERF_EVENT_STATE_DEAD;
4705 raw_spin_unlock_irq(&ctx->lock);
4707 perf_event_ctx_unlock(event, ctx);
4710 mutex_lock(&event->child_mutex);
4711 list_for_each_entry(child, &event->child_list, child_list) {
4714 * Cannot change, child events are not migrated, see the
4715 * comment with perf_event_ctx_lock_nested().
4717 ctx = READ_ONCE(child->ctx);
4719 * Since child_mutex nests inside ctx::mutex, we must jump
4720 * through hoops. We start by grabbing a reference on the ctx.
4722 * Since the event cannot get freed while we hold the
4723 * child_mutex, the context must also exist and have a !0
4729 * Now that we have a ctx ref, we can drop child_mutex, and
4730 * acquire ctx::mutex without fear of it going away. Then we
4731 * can re-acquire child_mutex.
4733 mutex_unlock(&event->child_mutex);
4734 mutex_lock(&ctx->mutex);
4735 mutex_lock(&event->child_mutex);
4738 * Now that we hold ctx::mutex and child_mutex, revalidate our
4739 * state, if child is still the first entry, it didn't get freed
4740 * and we can continue doing so.
4742 tmp = list_first_entry_or_null(&event->child_list,
4743 struct perf_event, child_list);
4745 perf_remove_from_context(child, DETACH_GROUP);
4746 list_move(&child->child_list, &free_list);
4748 * This matches the refcount bump in inherit_event();
4749 * this can't be the last reference.
4754 mutex_unlock(&event->child_mutex);
4755 mutex_unlock(&ctx->mutex);
4759 mutex_unlock(&event->child_mutex);
4761 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4762 void *var = &child->ctx->refcount;
4764 list_del(&child->child_list);
4768 * Wake any perf_event_free_task() waiting for this event to be
4771 smp_mb(); /* pairs with wait_var_event() */
4776 put_event(event); /* Must be the 'last' reference */
4779 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4782 * Called when the last reference to the file is gone.
4784 static int perf_release(struct inode *inode, struct file *file)
4786 perf_event_release_kernel(file->private_data);
4790 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4792 struct perf_event *child;
4798 mutex_lock(&event->child_mutex);
4800 (void)perf_event_read(event, false);
4801 total += perf_event_count(event);
4803 *enabled += event->total_time_enabled +
4804 atomic64_read(&event->child_total_time_enabled);
4805 *running += event->total_time_running +
4806 atomic64_read(&event->child_total_time_running);
4808 list_for_each_entry(child, &event->child_list, child_list) {
4809 (void)perf_event_read(child, false);
4810 total += perf_event_count(child);
4811 *enabled += child->total_time_enabled;
4812 *running += child->total_time_running;
4814 mutex_unlock(&event->child_mutex);
4819 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4821 struct perf_event_context *ctx;
4824 ctx = perf_event_ctx_lock(event);
4825 count = __perf_event_read_value(event, enabled, running);
4826 perf_event_ctx_unlock(event, ctx);
4830 EXPORT_SYMBOL_GPL(perf_event_read_value);
4832 static int __perf_read_group_add(struct perf_event *leader,
4833 u64 read_format, u64 *values)
4835 struct perf_event_context *ctx = leader->ctx;
4836 struct perf_event *sub;
4837 unsigned long flags;
4838 int n = 1; /* skip @nr */
4841 ret = perf_event_read(leader, true);
4845 raw_spin_lock_irqsave(&ctx->lock, flags);
4848 * Since we co-schedule groups, {enabled,running} times of siblings
4849 * will be identical to those of the leader, so we only publish one
4852 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4853 values[n++] += leader->total_time_enabled +
4854 atomic64_read(&leader->child_total_time_enabled);
4857 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4858 values[n++] += leader->total_time_running +
4859 atomic64_read(&leader->child_total_time_running);
4863 * Write {count,id} tuples for every sibling.
4865 values[n++] += perf_event_count(leader);
4866 if (read_format & PERF_FORMAT_ID)
4867 values[n++] = primary_event_id(leader);
4869 for_each_sibling_event(sub, leader) {
4870 values[n++] += perf_event_count(sub);
4871 if (read_format & PERF_FORMAT_ID)
4872 values[n++] = primary_event_id(sub);
4875 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4879 static int perf_read_group(struct perf_event *event,
4880 u64 read_format, char __user *buf)
4882 struct perf_event *leader = event->group_leader, *child;
4883 struct perf_event_context *ctx = leader->ctx;
4887 lockdep_assert_held(&ctx->mutex);
4889 values = kzalloc(event->read_size, GFP_KERNEL);
4893 values[0] = 1 + leader->nr_siblings;
4896 * By locking the child_mutex of the leader we effectively
4897 * lock the child list of all siblings.. XXX explain how.
4899 mutex_lock(&leader->child_mutex);
4901 ret = __perf_read_group_add(leader, read_format, values);
4905 list_for_each_entry(child, &leader->child_list, child_list) {
4906 ret = __perf_read_group_add(child, read_format, values);
4911 mutex_unlock(&leader->child_mutex);
4913 ret = event->read_size;
4914 if (copy_to_user(buf, values, event->read_size))
4919 mutex_unlock(&leader->child_mutex);
4925 static int perf_read_one(struct perf_event *event,
4926 u64 read_format, char __user *buf)
4928 u64 enabled, running;
4932 values[n++] = __perf_event_read_value(event, &enabled, &running);
4933 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4934 values[n++] = enabled;
4935 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4936 values[n++] = running;
4937 if (read_format & PERF_FORMAT_ID)
4938 values[n++] = primary_event_id(event);
4940 if (copy_to_user(buf, values, n * sizeof(u64)))
4943 return n * sizeof(u64);
4946 static bool is_event_hup(struct perf_event *event)
4950 if (event->state > PERF_EVENT_STATE_EXIT)
4953 mutex_lock(&event->child_mutex);
4954 no_children = list_empty(&event->child_list);
4955 mutex_unlock(&event->child_mutex);
4960 * Read the performance event - simple non blocking version for now
4963 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4965 u64 read_format = event->attr.read_format;
4969 * Return end-of-file for a read on an event that is in
4970 * error state (i.e. because it was pinned but it couldn't be
4971 * scheduled on to the CPU at some point).
4973 if (event->state == PERF_EVENT_STATE_ERROR)
4976 if (count < event->read_size)
4979 WARN_ON_ONCE(event->ctx->parent_ctx);
4980 if (read_format & PERF_FORMAT_GROUP)
4981 ret = perf_read_group(event, read_format, buf);
4983 ret = perf_read_one(event, read_format, buf);
4989 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4991 struct perf_event *event = file->private_data;
4992 struct perf_event_context *ctx;
4995 ctx = perf_event_ctx_lock(event);
4996 ret = __perf_read(event, buf, count);
4997 perf_event_ctx_unlock(event, ctx);
5002 static __poll_t perf_poll(struct file *file, poll_table *wait)
5004 struct perf_event *event = file->private_data;
5005 struct ring_buffer *rb;
5006 __poll_t events = EPOLLHUP;
5008 poll_wait(file, &event->waitq, wait);
5010 if (is_event_hup(event))
5014 * Pin the event->rb by taking event->mmap_mutex; otherwise
5015 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5017 mutex_lock(&event->mmap_mutex);
5020 events = atomic_xchg(&rb->poll, 0);
5021 mutex_unlock(&event->mmap_mutex);
5025 static void _perf_event_reset(struct perf_event *event)
5027 (void)perf_event_read(event, false);
5028 local64_set(&event->count, 0);
5029 perf_event_update_userpage(event);
5033 * Holding the top-level event's child_mutex means that any
5034 * descendant process that has inherited this event will block
5035 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5036 * task existence requirements of perf_event_enable/disable.
5038 static void perf_event_for_each_child(struct perf_event *event,
5039 void (*func)(struct perf_event *))
5041 struct perf_event *child;
5043 WARN_ON_ONCE(event->ctx->parent_ctx);
5045 mutex_lock(&event->child_mutex);
5047 list_for_each_entry(child, &event->child_list, child_list)
5049 mutex_unlock(&event->child_mutex);
5052 static void perf_event_for_each(struct perf_event *event,
5053 void (*func)(struct perf_event *))
5055 struct perf_event_context *ctx = event->ctx;
5056 struct perf_event *sibling;
5058 lockdep_assert_held(&ctx->mutex);
5060 event = event->group_leader;
5062 perf_event_for_each_child(event, func);
5063 for_each_sibling_event(sibling, event)
5064 perf_event_for_each_child(sibling, func);
5067 static void __perf_event_period(struct perf_event *event,
5068 struct perf_cpu_context *cpuctx,
5069 struct perf_event_context *ctx,
5072 u64 value = *((u64 *)info);
5075 if (event->attr.freq) {
5076 event->attr.sample_freq = value;
5078 event->attr.sample_period = value;
5079 event->hw.sample_period = value;
5082 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5084 perf_pmu_disable(ctx->pmu);
5086 * We could be throttled; unthrottle now to avoid the tick
5087 * trying to unthrottle while we already re-started the event.
5089 if (event->hw.interrupts == MAX_INTERRUPTS) {
5090 event->hw.interrupts = 0;
5091 perf_log_throttle(event, 1);
5093 event->pmu->stop(event, PERF_EF_UPDATE);
5096 local64_set(&event->hw.period_left, 0);
5099 event->pmu->start(event, PERF_EF_RELOAD);
5100 perf_pmu_enable(ctx->pmu);
5104 static int perf_event_check_period(struct perf_event *event, u64 value)
5106 return event->pmu->check_period(event, value);
5109 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5113 if (!is_sampling_event(event))
5116 if (copy_from_user(&value, arg, sizeof(value)))
5122 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5125 if (perf_event_check_period(event, value))
5128 if (!event->attr.freq && (value & (1ULL << 63)))
5131 event_function_call(event, __perf_event_period, &value);
5136 static const struct file_operations perf_fops;
5138 static inline int perf_fget_light(int fd, struct fd *p)
5140 struct fd f = fdget(fd);
5144 if (f.file->f_op != &perf_fops) {
5152 static int perf_event_set_output(struct perf_event *event,
5153 struct perf_event *output_event);
5154 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5155 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5156 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5157 struct perf_event_attr *attr);
5159 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5161 void (*func)(struct perf_event *);
5165 case PERF_EVENT_IOC_ENABLE:
5166 func = _perf_event_enable;
5168 case PERF_EVENT_IOC_DISABLE:
5169 func = _perf_event_disable;
5171 case PERF_EVENT_IOC_RESET:
5172 func = _perf_event_reset;
5175 case PERF_EVENT_IOC_REFRESH:
5176 return _perf_event_refresh(event, arg);
5178 case PERF_EVENT_IOC_PERIOD:
5179 return perf_event_period(event, (u64 __user *)arg);
5181 case PERF_EVENT_IOC_ID:
5183 u64 id = primary_event_id(event);
5185 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5190 case PERF_EVENT_IOC_SET_OUTPUT:
5194 struct perf_event *output_event;
5196 ret = perf_fget_light(arg, &output);
5199 output_event = output.file->private_data;
5200 ret = perf_event_set_output(event, output_event);
5203 ret = perf_event_set_output(event, NULL);
5208 case PERF_EVENT_IOC_SET_FILTER:
5209 return perf_event_set_filter(event, (void __user *)arg);
5211 case PERF_EVENT_IOC_SET_BPF:
5212 return perf_event_set_bpf_prog(event, arg);
5214 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5215 struct ring_buffer *rb;
5218 rb = rcu_dereference(event->rb);
5219 if (!rb || !rb->nr_pages) {
5223 rb_toggle_paused(rb, !!arg);
5228 case PERF_EVENT_IOC_QUERY_BPF:
5229 return perf_event_query_prog_array(event, (void __user *)arg);
5231 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5232 struct perf_event_attr new_attr;
5233 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5239 return perf_event_modify_attr(event, &new_attr);
5245 if (flags & PERF_IOC_FLAG_GROUP)
5246 perf_event_for_each(event, func);
5248 perf_event_for_each_child(event, func);
5253 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5255 struct perf_event *event = file->private_data;
5256 struct perf_event_context *ctx;
5259 ctx = perf_event_ctx_lock(event);
5260 ret = _perf_ioctl(event, cmd, arg);
5261 perf_event_ctx_unlock(event, ctx);
5266 #ifdef CONFIG_COMPAT
5267 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5270 switch (_IOC_NR(cmd)) {
5271 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5272 case _IOC_NR(PERF_EVENT_IOC_ID):
5273 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5274 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5275 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5276 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5277 cmd &= ~IOCSIZE_MASK;
5278 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5282 return perf_ioctl(file, cmd, arg);
5285 # define perf_compat_ioctl NULL
5288 int perf_event_task_enable(void)
5290 struct perf_event_context *ctx;
5291 struct perf_event *event;
5293 mutex_lock(¤t->perf_event_mutex);
5294 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5295 ctx = perf_event_ctx_lock(event);
5296 perf_event_for_each_child(event, _perf_event_enable);
5297 perf_event_ctx_unlock(event, ctx);
5299 mutex_unlock(¤t->perf_event_mutex);
5304 int perf_event_task_disable(void)
5306 struct perf_event_context *ctx;
5307 struct perf_event *event;
5309 mutex_lock(¤t->perf_event_mutex);
5310 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5311 ctx = perf_event_ctx_lock(event);
5312 perf_event_for_each_child(event, _perf_event_disable);
5313 perf_event_ctx_unlock(event, ctx);
5315 mutex_unlock(¤t->perf_event_mutex);
5320 static int perf_event_index(struct perf_event *event)
5322 if (event->hw.state & PERF_HES_STOPPED)
5325 if (event->state != PERF_EVENT_STATE_ACTIVE)
5328 return event->pmu->event_idx(event);
5331 static void calc_timer_values(struct perf_event *event,
5338 *now = perf_clock();
5339 ctx_time = event->shadow_ctx_time + *now;
5340 __perf_update_times(event, ctx_time, enabled, running);
5343 static void perf_event_init_userpage(struct perf_event *event)
5345 struct perf_event_mmap_page *userpg;
5346 struct ring_buffer *rb;
5349 rb = rcu_dereference(event->rb);
5353 userpg = rb->user_page;
5355 /* Allow new userspace to detect that bit 0 is deprecated */
5356 userpg->cap_bit0_is_deprecated = 1;
5357 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5358 userpg->data_offset = PAGE_SIZE;
5359 userpg->data_size = perf_data_size(rb);
5365 void __weak arch_perf_update_userpage(
5366 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5371 * Callers need to ensure there can be no nesting of this function, otherwise
5372 * the seqlock logic goes bad. We can not serialize this because the arch
5373 * code calls this from NMI context.
5375 void perf_event_update_userpage(struct perf_event *event)
5377 struct perf_event_mmap_page *userpg;
5378 struct ring_buffer *rb;
5379 u64 enabled, running, now;
5382 rb = rcu_dereference(event->rb);
5387 * compute total_time_enabled, total_time_running
5388 * based on snapshot values taken when the event
5389 * was last scheduled in.
5391 * we cannot simply called update_context_time()
5392 * because of locking issue as we can be called in
5395 calc_timer_values(event, &now, &enabled, &running);
5397 userpg = rb->user_page;
5399 * Disable preemption to guarantee consistent time stamps are stored to
5405 userpg->index = perf_event_index(event);
5406 userpg->offset = perf_event_count(event);
5408 userpg->offset -= local64_read(&event->hw.prev_count);
5410 userpg->time_enabled = enabled +
5411 atomic64_read(&event->child_total_time_enabled);
5413 userpg->time_running = running +
5414 atomic64_read(&event->child_total_time_running);
5416 arch_perf_update_userpage(event, userpg, now);
5424 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5426 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5428 struct perf_event *event = vmf->vma->vm_file->private_data;
5429 struct ring_buffer *rb;
5430 vm_fault_t ret = VM_FAULT_SIGBUS;
5432 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5433 if (vmf->pgoff == 0)
5439 rb = rcu_dereference(event->rb);
5443 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5446 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5450 get_page(vmf->page);
5451 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5452 vmf->page->index = vmf->pgoff;
5461 static void ring_buffer_attach(struct perf_event *event,
5462 struct ring_buffer *rb)
5464 struct ring_buffer *old_rb = NULL;
5465 unsigned long flags;
5469 * Should be impossible, we set this when removing
5470 * event->rb_entry and wait/clear when adding event->rb_entry.
5472 WARN_ON_ONCE(event->rcu_pending);
5475 spin_lock_irqsave(&old_rb->event_lock, flags);
5476 list_del_rcu(&event->rb_entry);
5477 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5479 event->rcu_batches = get_state_synchronize_rcu();
5480 event->rcu_pending = 1;
5484 if (event->rcu_pending) {
5485 cond_synchronize_rcu(event->rcu_batches);
5486 event->rcu_pending = 0;
5489 spin_lock_irqsave(&rb->event_lock, flags);
5490 list_add_rcu(&event->rb_entry, &rb->event_list);
5491 spin_unlock_irqrestore(&rb->event_lock, flags);
5495 * Avoid racing with perf_mmap_close(AUX): stop the event
5496 * before swizzling the event::rb pointer; if it's getting
5497 * unmapped, its aux_mmap_count will be 0 and it won't
5498 * restart. See the comment in __perf_pmu_output_stop().
5500 * Data will inevitably be lost when set_output is done in
5501 * mid-air, but then again, whoever does it like this is
5502 * not in for the data anyway.
5505 perf_event_stop(event, 0);
5507 rcu_assign_pointer(event->rb, rb);
5510 ring_buffer_put(old_rb);
5512 * Since we detached before setting the new rb, so that we
5513 * could attach the new rb, we could have missed a wakeup.
5516 wake_up_all(&event->waitq);
5520 static void ring_buffer_wakeup(struct perf_event *event)
5522 struct ring_buffer *rb;
5525 rb = rcu_dereference(event->rb);
5527 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5528 wake_up_all(&event->waitq);
5533 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5535 struct ring_buffer *rb;
5538 rb = rcu_dereference(event->rb);
5540 if (!refcount_inc_not_zero(&rb->refcount))
5548 void ring_buffer_put(struct ring_buffer *rb)
5550 if (!refcount_dec_and_test(&rb->refcount))
5553 WARN_ON_ONCE(!list_empty(&rb->event_list));
5555 call_rcu(&rb->rcu_head, rb_free_rcu);
5558 static void perf_mmap_open(struct vm_area_struct *vma)
5560 struct perf_event *event = vma->vm_file->private_data;
5562 atomic_inc(&event->mmap_count);
5563 atomic_inc(&event->rb->mmap_count);
5566 atomic_inc(&event->rb->aux_mmap_count);
5568 if (event->pmu->event_mapped)
5569 event->pmu->event_mapped(event, vma->vm_mm);
5572 static void perf_pmu_output_stop(struct perf_event *event);
5575 * A buffer can be mmap()ed multiple times; either directly through the same
5576 * event, or through other events by use of perf_event_set_output().
5578 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5579 * the buffer here, where we still have a VM context. This means we need
5580 * to detach all events redirecting to us.
5582 static void perf_mmap_close(struct vm_area_struct *vma)
5584 struct perf_event *event = vma->vm_file->private_data;
5586 struct ring_buffer *rb = ring_buffer_get(event);
5587 struct user_struct *mmap_user = rb->mmap_user;
5588 int mmap_locked = rb->mmap_locked;
5589 unsigned long size = perf_data_size(rb);
5591 if (event->pmu->event_unmapped)
5592 event->pmu->event_unmapped(event, vma->vm_mm);
5595 * rb->aux_mmap_count will always drop before rb->mmap_count and
5596 * event->mmap_count, so it is ok to use event->mmap_mutex to
5597 * serialize with perf_mmap here.
5599 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5600 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5602 * Stop all AUX events that are writing to this buffer,
5603 * so that we can free its AUX pages and corresponding PMU
5604 * data. Note that after rb::aux_mmap_count dropped to zero,
5605 * they won't start any more (see perf_aux_output_begin()).
5607 perf_pmu_output_stop(event);
5609 /* now it's safe to free the pages */
5610 if (!rb->aux_mmap_locked)
5611 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5613 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5615 /* this has to be the last one */
5617 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5619 mutex_unlock(&event->mmap_mutex);
5622 atomic_dec(&rb->mmap_count);
5624 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5627 ring_buffer_attach(event, NULL);
5628 mutex_unlock(&event->mmap_mutex);
5630 /* If there's still other mmap()s of this buffer, we're done. */
5631 if (atomic_read(&rb->mmap_count))
5635 * No other mmap()s, detach from all other events that might redirect
5636 * into the now unreachable buffer. Somewhat complicated by the
5637 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5641 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5642 if (!atomic_long_inc_not_zero(&event->refcount)) {
5644 * This event is en-route to free_event() which will
5645 * detach it and remove it from the list.
5651 mutex_lock(&event->mmap_mutex);
5653 * Check we didn't race with perf_event_set_output() which can
5654 * swizzle the rb from under us while we were waiting to
5655 * acquire mmap_mutex.
5657 * If we find a different rb; ignore this event, a next
5658 * iteration will no longer find it on the list. We have to
5659 * still restart the iteration to make sure we're not now
5660 * iterating the wrong list.
5662 if (event->rb == rb)
5663 ring_buffer_attach(event, NULL);
5665 mutex_unlock(&event->mmap_mutex);
5669 * Restart the iteration; either we're on the wrong list or
5670 * destroyed its integrity by doing a deletion.
5677 * It could be there's still a few 0-ref events on the list; they'll
5678 * get cleaned up by free_event() -- they'll also still have their
5679 * ref on the rb and will free it whenever they are done with it.
5681 * Aside from that, this buffer is 'fully' detached and unmapped,
5682 * undo the VM accounting.
5685 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5686 &mmap_user->locked_vm);
5687 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5688 free_uid(mmap_user);
5691 ring_buffer_put(rb); /* could be last */
5694 static const struct vm_operations_struct perf_mmap_vmops = {
5695 .open = perf_mmap_open,
5696 .close = perf_mmap_close, /* non mergeable */
5697 .fault = perf_mmap_fault,
5698 .page_mkwrite = perf_mmap_fault,
5701 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5703 struct perf_event *event = file->private_data;
5704 unsigned long user_locked, user_lock_limit;
5705 struct user_struct *user = current_user();
5706 unsigned long locked, lock_limit;
5707 struct ring_buffer *rb = NULL;
5708 unsigned long vma_size;
5709 unsigned long nr_pages;
5710 long user_extra = 0, extra = 0;
5711 int ret = 0, flags = 0;
5714 * Don't allow mmap() of inherited per-task counters. This would
5715 * create a performance issue due to all children writing to the
5718 if (event->cpu == -1 && event->attr.inherit)
5721 if (!(vma->vm_flags & VM_SHARED))
5724 vma_size = vma->vm_end - vma->vm_start;
5726 if (vma->vm_pgoff == 0) {
5727 nr_pages = (vma_size / PAGE_SIZE) - 1;
5730 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5731 * mapped, all subsequent mappings should have the same size
5732 * and offset. Must be above the normal perf buffer.
5734 u64 aux_offset, aux_size;
5739 nr_pages = vma_size / PAGE_SIZE;
5741 mutex_lock(&event->mmap_mutex);
5748 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5749 aux_size = READ_ONCE(rb->user_page->aux_size);
5751 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5754 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5757 /* already mapped with a different offset */
5758 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5761 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5764 /* already mapped with a different size */
5765 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5768 if (!is_power_of_2(nr_pages))
5771 if (!atomic_inc_not_zero(&rb->mmap_count))
5774 if (rb_has_aux(rb)) {
5775 atomic_inc(&rb->aux_mmap_count);
5780 atomic_set(&rb->aux_mmap_count, 1);
5781 user_extra = nr_pages;
5787 * If we have rb pages ensure they're a power-of-two number, so we
5788 * can do bitmasks instead of modulo.
5790 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5793 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5796 WARN_ON_ONCE(event->ctx->parent_ctx);
5798 mutex_lock(&event->mmap_mutex);
5800 if (event->rb->nr_pages != nr_pages) {
5805 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5807 * Raced against perf_mmap_close() through
5808 * perf_event_set_output(). Try again, hope for better
5811 mutex_unlock(&event->mmap_mutex);
5818 user_extra = nr_pages + 1;
5821 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5824 * Increase the limit linearly with more CPUs:
5826 user_lock_limit *= num_online_cpus();
5828 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5830 if (user_locked <= user_lock_limit) {
5831 /* charge all to locked_vm */
5832 } else if (atomic_long_read(&user->locked_vm) >= user_lock_limit) {
5833 /* charge all to pinned_vm */
5838 * charge locked_vm until it hits user_lock_limit;
5839 * charge the rest from pinned_vm
5841 extra = user_locked - user_lock_limit;
5842 user_extra -= extra;
5845 lock_limit = rlimit(RLIMIT_MEMLOCK);
5846 lock_limit >>= PAGE_SHIFT;
5847 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5849 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5850 !capable(CAP_IPC_LOCK)) {
5855 WARN_ON(!rb && event->rb);
5857 if (vma->vm_flags & VM_WRITE)
5858 flags |= RING_BUFFER_WRITABLE;
5861 rb = rb_alloc(nr_pages,
5862 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5870 atomic_set(&rb->mmap_count, 1);
5871 rb->mmap_user = get_current_user();
5872 rb->mmap_locked = extra;
5874 ring_buffer_attach(event, rb);
5876 perf_event_init_userpage(event);
5877 perf_event_update_userpage(event);
5879 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5880 event->attr.aux_watermark, flags);
5882 rb->aux_mmap_locked = extra;
5887 atomic_long_add(user_extra, &user->locked_vm);
5888 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5890 atomic_inc(&event->mmap_count);
5892 atomic_dec(&rb->mmap_count);
5895 mutex_unlock(&event->mmap_mutex);
5898 * Since pinned accounting is per vm we cannot allow fork() to copy our
5901 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5902 vma->vm_ops = &perf_mmap_vmops;
5904 if (event->pmu->event_mapped)
5905 event->pmu->event_mapped(event, vma->vm_mm);
5910 static int perf_fasync(int fd, struct file *filp, int on)
5912 struct inode *inode = file_inode(filp);
5913 struct perf_event *event = filp->private_data;
5917 retval = fasync_helper(fd, filp, on, &event->fasync);
5918 inode_unlock(inode);
5926 static const struct file_operations perf_fops = {
5927 .llseek = no_llseek,
5928 .release = perf_release,
5931 .unlocked_ioctl = perf_ioctl,
5932 .compat_ioctl = perf_compat_ioctl,
5934 .fasync = perf_fasync,
5940 * If there's data, ensure we set the poll() state and publish everything
5941 * to user-space before waking everybody up.
5944 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5946 /* only the parent has fasync state */
5948 event = event->parent;
5949 return &event->fasync;
5952 void perf_event_wakeup(struct perf_event *event)
5954 ring_buffer_wakeup(event);
5956 if (event->pending_kill) {
5957 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5958 event->pending_kill = 0;
5962 static void perf_pending_event_disable(struct perf_event *event)
5964 int cpu = READ_ONCE(event->pending_disable);
5969 if (cpu == smp_processor_id()) {
5970 WRITE_ONCE(event->pending_disable, -1);
5971 perf_event_disable_local(event);
5978 * perf_event_disable_inatomic()
5979 * @pending_disable = CPU-A;
5983 * @pending_disable = -1;
5986 * perf_event_disable_inatomic()
5987 * @pending_disable = CPU-B;
5988 * irq_work_queue(); // FAILS
5991 * perf_pending_event()
5993 * But the event runs on CPU-B and wants disabling there.
5995 irq_work_queue_on(&event->pending, cpu);
5998 static void perf_pending_event(struct irq_work *entry)
6000 struct perf_event *event = container_of(entry, struct perf_event, pending);
6003 rctx = perf_swevent_get_recursion_context();
6005 * If we 'fail' here, that's OK, it means recursion is already disabled
6006 * and we won't recurse 'further'.
6009 perf_pending_event_disable(event);
6011 if (event->pending_wakeup) {
6012 event->pending_wakeup = 0;
6013 perf_event_wakeup(event);
6017 perf_swevent_put_recursion_context(rctx);
6021 * We assume there is only KVM supporting the callbacks.
6022 * Later on, we might change it to a list if there is
6023 * another virtualization implementation supporting the callbacks.
6025 struct perf_guest_info_callbacks *perf_guest_cbs;
6027 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6029 perf_guest_cbs = cbs;
6032 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6034 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6036 perf_guest_cbs = NULL;
6039 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6042 perf_output_sample_regs(struct perf_output_handle *handle,
6043 struct pt_regs *regs, u64 mask)
6046 DECLARE_BITMAP(_mask, 64);
6048 bitmap_from_u64(_mask, mask);
6049 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6052 val = perf_reg_value(regs, bit);
6053 perf_output_put(handle, val);
6057 static void perf_sample_regs_user(struct perf_regs *regs_user,
6058 struct pt_regs *regs,
6059 struct pt_regs *regs_user_copy)
6061 if (user_mode(regs)) {
6062 regs_user->abi = perf_reg_abi(current);
6063 regs_user->regs = regs;
6064 } else if (!(current->flags & PF_KTHREAD)) {
6065 perf_get_regs_user(regs_user, regs, regs_user_copy);
6067 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6068 regs_user->regs = NULL;
6072 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6073 struct pt_regs *regs)
6075 regs_intr->regs = regs;
6076 regs_intr->abi = perf_reg_abi(current);
6081 * Get remaining task size from user stack pointer.
6083 * It'd be better to take stack vma map and limit this more
6084 * precisely, but there's no way to get it safely under interrupt,
6085 * so using TASK_SIZE as limit.
6087 static u64 perf_ustack_task_size(struct pt_regs *regs)
6089 unsigned long addr = perf_user_stack_pointer(regs);
6091 if (!addr || addr >= TASK_SIZE)
6094 return TASK_SIZE - addr;
6098 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6099 struct pt_regs *regs)
6103 /* No regs, no stack pointer, no dump. */
6108 * Check if we fit in with the requested stack size into the:
6110 * If we don't, we limit the size to the TASK_SIZE.
6112 * - remaining sample size
6113 * If we don't, we customize the stack size to
6114 * fit in to the remaining sample size.
6117 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6118 stack_size = min(stack_size, (u16) task_size);
6120 /* Current header size plus static size and dynamic size. */
6121 header_size += 2 * sizeof(u64);
6123 /* Do we fit in with the current stack dump size? */
6124 if ((u16) (header_size + stack_size) < header_size) {
6126 * If we overflow the maximum size for the sample,
6127 * we customize the stack dump size to fit in.
6129 stack_size = USHRT_MAX - header_size - sizeof(u64);
6130 stack_size = round_up(stack_size, sizeof(u64));
6137 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6138 struct pt_regs *regs)
6140 /* Case of a kernel thread, nothing to dump */
6143 perf_output_put(handle, size);
6153 * - the size requested by user or the best one we can fit
6154 * in to the sample max size
6156 * - user stack dump data
6158 * - the actual dumped size
6162 perf_output_put(handle, dump_size);
6165 sp = perf_user_stack_pointer(regs);
6168 rem = __output_copy_user(handle, (void *) sp, dump_size);
6170 dyn_size = dump_size - rem;
6172 perf_output_skip(handle, rem);
6175 perf_output_put(handle, dyn_size);
6179 static void __perf_event_header__init_id(struct perf_event_header *header,
6180 struct perf_sample_data *data,
6181 struct perf_event *event)
6183 u64 sample_type = event->attr.sample_type;
6185 data->type = sample_type;
6186 header->size += event->id_header_size;
6188 if (sample_type & PERF_SAMPLE_TID) {
6189 /* namespace issues */
6190 data->tid_entry.pid = perf_event_pid(event, current);
6191 data->tid_entry.tid = perf_event_tid(event, current);
6194 if (sample_type & PERF_SAMPLE_TIME)
6195 data->time = perf_event_clock(event);
6197 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6198 data->id = primary_event_id(event);
6200 if (sample_type & PERF_SAMPLE_STREAM_ID)
6201 data->stream_id = event->id;
6203 if (sample_type & PERF_SAMPLE_CPU) {
6204 data->cpu_entry.cpu = raw_smp_processor_id();
6205 data->cpu_entry.reserved = 0;
6209 void perf_event_header__init_id(struct perf_event_header *header,
6210 struct perf_sample_data *data,
6211 struct perf_event *event)
6213 if (event->attr.sample_id_all)
6214 __perf_event_header__init_id(header, data, event);
6217 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6218 struct perf_sample_data *data)
6220 u64 sample_type = data->type;
6222 if (sample_type & PERF_SAMPLE_TID)
6223 perf_output_put(handle, data->tid_entry);
6225 if (sample_type & PERF_SAMPLE_TIME)
6226 perf_output_put(handle, data->time);
6228 if (sample_type & PERF_SAMPLE_ID)
6229 perf_output_put(handle, data->id);
6231 if (sample_type & PERF_SAMPLE_STREAM_ID)
6232 perf_output_put(handle, data->stream_id);
6234 if (sample_type & PERF_SAMPLE_CPU)
6235 perf_output_put(handle, data->cpu_entry);
6237 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6238 perf_output_put(handle, data->id);
6241 void perf_event__output_id_sample(struct perf_event *event,
6242 struct perf_output_handle *handle,
6243 struct perf_sample_data *sample)
6245 if (event->attr.sample_id_all)
6246 __perf_event__output_id_sample(handle, sample);
6249 static void perf_output_read_one(struct perf_output_handle *handle,
6250 struct perf_event *event,
6251 u64 enabled, u64 running)
6253 u64 read_format = event->attr.read_format;
6257 values[n++] = perf_event_count(event);
6258 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6259 values[n++] = enabled +
6260 atomic64_read(&event->child_total_time_enabled);
6262 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6263 values[n++] = running +
6264 atomic64_read(&event->child_total_time_running);
6266 if (read_format & PERF_FORMAT_ID)
6267 values[n++] = primary_event_id(event);
6269 __output_copy(handle, values, n * sizeof(u64));
6272 static void perf_output_read_group(struct perf_output_handle *handle,
6273 struct perf_event *event,
6274 u64 enabled, u64 running)
6276 struct perf_event *leader = event->group_leader, *sub;
6277 u64 read_format = event->attr.read_format;
6281 values[n++] = 1 + leader->nr_siblings;
6283 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6284 values[n++] = enabled;
6286 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6287 values[n++] = running;
6289 if ((leader != event) &&
6290 (leader->state == PERF_EVENT_STATE_ACTIVE))
6291 leader->pmu->read(leader);
6293 values[n++] = perf_event_count(leader);
6294 if (read_format & PERF_FORMAT_ID)
6295 values[n++] = primary_event_id(leader);
6297 __output_copy(handle, values, n * sizeof(u64));
6299 for_each_sibling_event(sub, leader) {
6302 if ((sub != event) &&
6303 (sub->state == PERF_EVENT_STATE_ACTIVE))
6304 sub->pmu->read(sub);
6306 values[n++] = perf_event_count(sub);
6307 if (read_format & PERF_FORMAT_ID)
6308 values[n++] = primary_event_id(sub);
6310 __output_copy(handle, values, n * sizeof(u64));
6314 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6315 PERF_FORMAT_TOTAL_TIME_RUNNING)
6318 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6320 * The problem is that its both hard and excessively expensive to iterate the
6321 * child list, not to mention that its impossible to IPI the children running
6322 * on another CPU, from interrupt/NMI context.
6324 static void perf_output_read(struct perf_output_handle *handle,
6325 struct perf_event *event)
6327 u64 enabled = 0, running = 0, now;
6328 u64 read_format = event->attr.read_format;
6331 * compute total_time_enabled, total_time_running
6332 * based on snapshot values taken when the event
6333 * was last scheduled in.
6335 * we cannot simply called update_context_time()
6336 * because of locking issue as we are called in
6339 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6340 calc_timer_values(event, &now, &enabled, &running);
6342 if (event->attr.read_format & PERF_FORMAT_GROUP)
6343 perf_output_read_group(handle, event, enabled, running);
6345 perf_output_read_one(handle, event, enabled, running);
6348 void perf_output_sample(struct perf_output_handle *handle,
6349 struct perf_event_header *header,
6350 struct perf_sample_data *data,
6351 struct perf_event *event)
6353 u64 sample_type = data->type;
6355 perf_output_put(handle, *header);
6357 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6358 perf_output_put(handle, data->id);
6360 if (sample_type & PERF_SAMPLE_IP)
6361 perf_output_put(handle, data->ip);
6363 if (sample_type & PERF_SAMPLE_TID)
6364 perf_output_put(handle, data->tid_entry);
6366 if (sample_type & PERF_SAMPLE_TIME)
6367 perf_output_put(handle, data->time);
6369 if (sample_type & PERF_SAMPLE_ADDR)
6370 perf_output_put(handle, data->addr);
6372 if (sample_type & PERF_SAMPLE_ID)
6373 perf_output_put(handle, data->id);
6375 if (sample_type & PERF_SAMPLE_STREAM_ID)
6376 perf_output_put(handle, data->stream_id);
6378 if (sample_type & PERF_SAMPLE_CPU)
6379 perf_output_put(handle, data->cpu_entry);
6381 if (sample_type & PERF_SAMPLE_PERIOD)
6382 perf_output_put(handle, data->period);
6384 if (sample_type & PERF_SAMPLE_READ)
6385 perf_output_read(handle, event);
6387 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6390 size += data->callchain->nr;
6391 size *= sizeof(u64);
6392 __output_copy(handle, data->callchain, size);
6395 if (sample_type & PERF_SAMPLE_RAW) {
6396 struct perf_raw_record *raw = data->raw;
6399 struct perf_raw_frag *frag = &raw->frag;
6401 perf_output_put(handle, raw->size);
6404 __output_custom(handle, frag->copy,
6405 frag->data, frag->size);
6407 __output_copy(handle, frag->data,
6410 if (perf_raw_frag_last(frag))
6415 __output_skip(handle, NULL, frag->pad);
6421 .size = sizeof(u32),
6424 perf_output_put(handle, raw);
6428 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6429 if (data->br_stack) {
6432 size = data->br_stack->nr
6433 * sizeof(struct perf_branch_entry);
6435 perf_output_put(handle, data->br_stack->nr);
6436 perf_output_copy(handle, data->br_stack->entries, size);
6439 * we always store at least the value of nr
6442 perf_output_put(handle, nr);
6446 if (sample_type & PERF_SAMPLE_REGS_USER) {
6447 u64 abi = data->regs_user.abi;
6450 * If there are no regs to dump, notice it through
6451 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6453 perf_output_put(handle, abi);
6456 u64 mask = event->attr.sample_regs_user;
6457 perf_output_sample_regs(handle,
6458 data->regs_user.regs,
6463 if (sample_type & PERF_SAMPLE_STACK_USER) {
6464 perf_output_sample_ustack(handle,
6465 data->stack_user_size,
6466 data->regs_user.regs);
6469 if (sample_type & PERF_SAMPLE_WEIGHT)
6470 perf_output_put(handle, data->weight);
6472 if (sample_type & PERF_SAMPLE_DATA_SRC)
6473 perf_output_put(handle, data->data_src.val);
6475 if (sample_type & PERF_SAMPLE_TRANSACTION)
6476 perf_output_put(handle, data->txn);
6478 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6479 u64 abi = data->regs_intr.abi;
6481 * If there are no regs to dump, notice it through
6482 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6484 perf_output_put(handle, abi);
6487 u64 mask = event->attr.sample_regs_intr;
6489 perf_output_sample_regs(handle,
6490 data->regs_intr.regs,
6495 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6496 perf_output_put(handle, data->phys_addr);
6498 if (!event->attr.watermark) {
6499 int wakeup_events = event->attr.wakeup_events;
6501 if (wakeup_events) {
6502 struct ring_buffer *rb = handle->rb;
6503 int events = local_inc_return(&rb->events);
6505 if (events >= wakeup_events) {
6506 local_sub(wakeup_events, &rb->events);
6507 local_inc(&rb->wakeup);
6513 static u64 perf_virt_to_phys(u64 virt)
6516 struct page *p = NULL;
6521 if (virt >= TASK_SIZE) {
6522 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6523 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6524 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6525 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6528 * Walking the pages tables for user address.
6529 * Interrupts are disabled, so it prevents any tear down
6530 * of the page tables.
6531 * Try IRQ-safe __get_user_pages_fast first.
6532 * If failed, leave phys_addr as 0.
6534 if ((current->mm != NULL) &&
6535 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6536 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6545 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6547 struct perf_callchain_entry *
6548 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6550 bool kernel = !event->attr.exclude_callchain_kernel;
6551 bool user = !event->attr.exclude_callchain_user;
6552 /* Disallow cross-task user callchains. */
6553 bool crosstask = event->ctx->task && event->ctx->task != current;
6554 const u32 max_stack = event->attr.sample_max_stack;
6555 struct perf_callchain_entry *callchain;
6557 if (!kernel && !user)
6558 return &__empty_callchain;
6560 callchain = get_perf_callchain(regs, 0, kernel, user,
6561 max_stack, crosstask, true);
6562 return callchain ?: &__empty_callchain;
6565 void perf_prepare_sample(struct perf_event_header *header,
6566 struct perf_sample_data *data,
6567 struct perf_event *event,
6568 struct pt_regs *regs)
6570 u64 sample_type = event->attr.sample_type;
6572 header->type = PERF_RECORD_SAMPLE;
6573 header->size = sizeof(*header) + event->header_size;
6576 header->misc |= perf_misc_flags(regs);
6578 __perf_event_header__init_id(header, data, event);
6580 if (sample_type & PERF_SAMPLE_IP)
6581 data->ip = perf_instruction_pointer(regs);
6583 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6586 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6587 data->callchain = perf_callchain(event, regs);
6589 size += data->callchain->nr;
6591 header->size += size * sizeof(u64);
6594 if (sample_type & PERF_SAMPLE_RAW) {
6595 struct perf_raw_record *raw = data->raw;
6599 struct perf_raw_frag *frag = &raw->frag;
6604 if (perf_raw_frag_last(frag))
6609 size = round_up(sum + sizeof(u32), sizeof(u64));
6610 raw->size = size - sizeof(u32);
6611 frag->pad = raw->size - sum;
6616 header->size += size;
6619 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6620 int size = sizeof(u64); /* nr */
6621 if (data->br_stack) {
6622 size += data->br_stack->nr
6623 * sizeof(struct perf_branch_entry);
6625 header->size += size;
6628 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6629 perf_sample_regs_user(&data->regs_user, regs,
6630 &data->regs_user_copy);
6632 if (sample_type & PERF_SAMPLE_REGS_USER) {
6633 /* regs dump ABI info */
6634 int size = sizeof(u64);
6636 if (data->regs_user.regs) {
6637 u64 mask = event->attr.sample_regs_user;
6638 size += hweight64(mask) * sizeof(u64);
6641 header->size += size;
6644 if (sample_type & PERF_SAMPLE_STACK_USER) {
6646 * Either we need PERF_SAMPLE_STACK_USER bit to be always
6647 * processed as the last one or have additional check added
6648 * in case new sample type is added, because we could eat
6649 * up the rest of the sample size.
6651 u16 stack_size = event->attr.sample_stack_user;
6652 u16 size = sizeof(u64);
6654 stack_size = perf_sample_ustack_size(stack_size, header->size,
6655 data->regs_user.regs);
6658 * If there is something to dump, add space for the dump
6659 * itself and for the field that tells the dynamic size,
6660 * which is how many have been actually dumped.
6663 size += sizeof(u64) + stack_size;
6665 data->stack_user_size = stack_size;
6666 header->size += size;
6669 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6670 /* regs dump ABI info */
6671 int size = sizeof(u64);
6673 perf_sample_regs_intr(&data->regs_intr, regs);
6675 if (data->regs_intr.regs) {
6676 u64 mask = event->attr.sample_regs_intr;
6678 size += hweight64(mask) * sizeof(u64);
6681 header->size += size;
6684 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6685 data->phys_addr = perf_virt_to_phys(data->addr);
6688 static __always_inline int
6689 __perf_event_output(struct perf_event *event,
6690 struct perf_sample_data *data,
6691 struct pt_regs *regs,
6692 int (*output_begin)(struct perf_output_handle *,
6693 struct perf_event *,
6696 struct perf_output_handle handle;
6697 struct perf_event_header header;
6700 /* protect the callchain buffers */
6703 perf_prepare_sample(&header, data, event, regs);
6705 err = output_begin(&handle, event, header.size);
6709 perf_output_sample(&handle, &header, data, event);
6711 perf_output_end(&handle);
6719 perf_event_output_forward(struct perf_event *event,
6720 struct perf_sample_data *data,
6721 struct pt_regs *regs)
6723 __perf_event_output(event, data, regs, perf_output_begin_forward);
6727 perf_event_output_backward(struct perf_event *event,
6728 struct perf_sample_data *data,
6729 struct pt_regs *regs)
6731 __perf_event_output(event, data, regs, perf_output_begin_backward);
6735 perf_event_output(struct perf_event *event,
6736 struct perf_sample_data *data,
6737 struct pt_regs *regs)
6739 return __perf_event_output(event, data, regs, perf_output_begin);
6746 struct perf_read_event {
6747 struct perf_event_header header;
6754 perf_event_read_event(struct perf_event *event,
6755 struct task_struct *task)
6757 struct perf_output_handle handle;
6758 struct perf_sample_data sample;
6759 struct perf_read_event read_event = {
6761 .type = PERF_RECORD_READ,
6763 .size = sizeof(read_event) + event->read_size,
6765 .pid = perf_event_pid(event, task),
6766 .tid = perf_event_tid(event, task),
6770 perf_event_header__init_id(&read_event.header, &sample, event);
6771 ret = perf_output_begin(&handle, event, read_event.header.size);
6775 perf_output_put(&handle, read_event);
6776 perf_output_read(&handle, event);
6777 perf_event__output_id_sample(event, &handle, &sample);
6779 perf_output_end(&handle);
6782 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6785 perf_iterate_ctx(struct perf_event_context *ctx,
6786 perf_iterate_f output,
6787 void *data, bool all)
6789 struct perf_event *event;
6791 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6793 if (event->state < PERF_EVENT_STATE_INACTIVE)
6795 if (!event_filter_match(event))
6799 output(event, data);
6803 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6805 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6806 struct perf_event *event;
6808 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6810 * Skip events that are not fully formed yet; ensure that
6811 * if we observe event->ctx, both event and ctx will be
6812 * complete enough. See perf_install_in_context().
6814 if (!smp_load_acquire(&event->ctx))
6817 if (event->state < PERF_EVENT_STATE_INACTIVE)
6819 if (!event_filter_match(event))
6821 output(event, data);
6826 * Iterate all events that need to receive side-band events.
6828 * For new callers; ensure that account_pmu_sb_event() includes
6829 * your event, otherwise it might not get delivered.
6832 perf_iterate_sb(perf_iterate_f output, void *data,
6833 struct perf_event_context *task_ctx)
6835 struct perf_event_context *ctx;
6842 * If we have task_ctx != NULL we only notify the task context itself.
6843 * The task_ctx is set only for EXIT events before releasing task
6847 perf_iterate_ctx(task_ctx, output, data, false);
6851 perf_iterate_sb_cpu(output, data);
6853 for_each_task_context_nr(ctxn) {
6854 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6856 perf_iterate_ctx(ctx, output, data, false);
6864 * Clear all file-based filters at exec, they'll have to be
6865 * re-instated when/if these objects are mmapped again.
6867 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6869 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6870 struct perf_addr_filter *filter;
6871 unsigned int restart = 0, count = 0;
6872 unsigned long flags;
6874 if (!has_addr_filter(event))
6877 raw_spin_lock_irqsave(&ifh->lock, flags);
6878 list_for_each_entry(filter, &ifh->list, entry) {
6879 if (filter->path.dentry) {
6880 event->addr_filter_ranges[count].start = 0;
6881 event->addr_filter_ranges[count].size = 0;
6889 event->addr_filters_gen++;
6890 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6893 perf_event_stop(event, 1);
6896 void perf_event_exec(void)
6898 struct perf_event_context *ctx;
6902 for_each_task_context_nr(ctxn) {
6903 ctx = current->perf_event_ctxp[ctxn];
6907 perf_event_enable_on_exec(ctxn);
6909 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6915 struct remote_output {
6916 struct ring_buffer *rb;
6920 static void __perf_event_output_stop(struct perf_event *event, void *data)
6922 struct perf_event *parent = event->parent;
6923 struct remote_output *ro = data;
6924 struct ring_buffer *rb = ro->rb;
6925 struct stop_event_data sd = {
6929 if (!has_aux(event))
6936 * In case of inheritance, it will be the parent that links to the
6937 * ring-buffer, but it will be the child that's actually using it.
6939 * We are using event::rb to determine if the event should be stopped,
6940 * however this may race with ring_buffer_attach() (through set_output),
6941 * which will make us skip the event that actually needs to be stopped.
6942 * So ring_buffer_attach() has to stop an aux event before re-assigning
6945 if (rcu_dereference(parent->rb) == rb)
6946 ro->err = __perf_event_stop(&sd);
6949 static int __perf_pmu_output_stop(void *info)
6951 struct perf_event *event = info;
6952 struct pmu *pmu = event->ctx->pmu;
6953 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6954 struct remote_output ro = {
6959 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6960 if (cpuctx->task_ctx)
6961 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6968 static void perf_pmu_output_stop(struct perf_event *event)
6970 struct perf_event *iter;
6975 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6977 * For per-CPU events, we need to make sure that neither they
6978 * nor their children are running; for cpu==-1 events it's
6979 * sufficient to stop the event itself if it's active, since
6980 * it can't have children.
6984 cpu = READ_ONCE(iter->oncpu);
6989 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6990 if (err == -EAGAIN) {
6999 * task tracking -- fork/exit
7001 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7004 struct perf_task_event {
7005 struct task_struct *task;
7006 struct perf_event_context *task_ctx;
7009 struct perf_event_header header;
7019 static int perf_event_task_match(struct perf_event *event)
7021 return event->attr.comm || event->attr.mmap ||
7022 event->attr.mmap2 || event->attr.mmap_data ||
7026 static void perf_event_task_output(struct perf_event *event,
7029 struct perf_task_event *task_event = data;
7030 struct perf_output_handle handle;
7031 struct perf_sample_data sample;
7032 struct task_struct *task = task_event->task;
7033 int ret, size = task_event->event_id.header.size;
7035 if (!perf_event_task_match(event))
7038 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7040 ret = perf_output_begin(&handle, event,
7041 task_event->event_id.header.size);
7045 task_event->event_id.pid = perf_event_pid(event, task);
7046 task_event->event_id.ppid = perf_event_pid(event, current);
7048 task_event->event_id.tid = perf_event_tid(event, task);
7049 task_event->event_id.ptid = perf_event_tid(event, current);
7051 task_event->event_id.time = perf_event_clock(event);
7053 perf_output_put(&handle, task_event->event_id);
7055 perf_event__output_id_sample(event, &handle, &sample);
7057 perf_output_end(&handle);
7059 task_event->event_id.header.size = size;
7062 static void perf_event_task(struct task_struct *task,
7063 struct perf_event_context *task_ctx,
7066 struct perf_task_event task_event;
7068 if (!atomic_read(&nr_comm_events) &&
7069 !atomic_read(&nr_mmap_events) &&
7070 !atomic_read(&nr_task_events))
7073 task_event = (struct perf_task_event){
7075 .task_ctx = task_ctx,
7078 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7080 .size = sizeof(task_event.event_id),
7090 perf_iterate_sb(perf_event_task_output,
7095 void perf_event_fork(struct task_struct *task)
7097 perf_event_task(task, NULL, 1);
7098 perf_event_namespaces(task);
7105 struct perf_comm_event {
7106 struct task_struct *task;
7111 struct perf_event_header header;
7118 static int perf_event_comm_match(struct perf_event *event)
7120 return event->attr.comm;
7123 static void perf_event_comm_output(struct perf_event *event,
7126 struct perf_comm_event *comm_event = data;
7127 struct perf_output_handle handle;
7128 struct perf_sample_data sample;
7129 int size = comm_event->event_id.header.size;
7132 if (!perf_event_comm_match(event))
7135 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7136 ret = perf_output_begin(&handle, event,
7137 comm_event->event_id.header.size);
7142 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7143 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7145 perf_output_put(&handle, comm_event->event_id);
7146 __output_copy(&handle, comm_event->comm,
7147 comm_event->comm_size);
7149 perf_event__output_id_sample(event, &handle, &sample);
7151 perf_output_end(&handle);
7153 comm_event->event_id.header.size = size;
7156 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7158 char comm[TASK_COMM_LEN];
7161 memset(comm, 0, sizeof(comm));
7162 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7163 size = ALIGN(strlen(comm)+1, sizeof(u64));
7165 comm_event->comm = comm;
7166 comm_event->comm_size = size;
7168 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7170 perf_iterate_sb(perf_event_comm_output,
7175 void perf_event_comm(struct task_struct *task, bool exec)
7177 struct perf_comm_event comm_event;
7179 if (!atomic_read(&nr_comm_events))
7182 comm_event = (struct perf_comm_event){
7188 .type = PERF_RECORD_COMM,
7189 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7197 perf_event_comm_event(&comm_event);
7201 * namespaces tracking
7204 struct perf_namespaces_event {
7205 struct task_struct *task;
7208 struct perf_event_header header;
7213 struct perf_ns_link_info link_info[NR_NAMESPACES];
7217 static int perf_event_namespaces_match(struct perf_event *event)
7219 return event->attr.namespaces;
7222 static void perf_event_namespaces_output(struct perf_event *event,
7225 struct perf_namespaces_event *namespaces_event = data;
7226 struct perf_output_handle handle;
7227 struct perf_sample_data sample;
7228 u16 header_size = namespaces_event->event_id.header.size;
7231 if (!perf_event_namespaces_match(event))
7234 perf_event_header__init_id(&namespaces_event->event_id.header,
7236 ret = perf_output_begin(&handle, event,
7237 namespaces_event->event_id.header.size);
7241 namespaces_event->event_id.pid = perf_event_pid(event,
7242 namespaces_event->task);
7243 namespaces_event->event_id.tid = perf_event_tid(event,
7244 namespaces_event->task);
7246 perf_output_put(&handle, namespaces_event->event_id);
7248 perf_event__output_id_sample(event, &handle, &sample);
7250 perf_output_end(&handle);
7252 namespaces_event->event_id.header.size = header_size;
7255 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7256 struct task_struct *task,
7257 const struct proc_ns_operations *ns_ops)
7259 struct path ns_path;
7260 struct inode *ns_inode;
7263 error = ns_get_path(&ns_path, task, ns_ops);
7265 ns_inode = ns_path.dentry->d_inode;
7266 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7267 ns_link_info->ino = ns_inode->i_ino;
7272 void perf_event_namespaces(struct task_struct *task)
7274 struct perf_namespaces_event namespaces_event;
7275 struct perf_ns_link_info *ns_link_info;
7277 if (!atomic_read(&nr_namespaces_events))
7280 namespaces_event = (struct perf_namespaces_event){
7284 .type = PERF_RECORD_NAMESPACES,
7286 .size = sizeof(namespaces_event.event_id),
7290 .nr_namespaces = NR_NAMESPACES,
7291 /* .link_info[NR_NAMESPACES] */
7295 ns_link_info = namespaces_event.event_id.link_info;
7297 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7298 task, &mntns_operations);
7300 #ifdef CONFIG_USER_NS
7301 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7302 task, &userns_operations);
7304 #ifdef CONFIG_NET_NS
7305 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7306 task, &netns_operations);
7308 #ifdef CONFIG_UTS_NS
7309 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7310 task, &utsns_operations);
7312 #ifdef CONFIG_IPC_NS
7313 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7314 task, &ipcns_operations);
7316 #ifdef CONFIG_PID_NS
7317 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7318 task, &pidns_operations);
7320 #ifdef CONFIG_CGROUPS
7321 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7322 task, &cgroupns_operations);
7325 perf_iterate_sb(perf_event_namespaces_output,
7334 struct perf_mmap_event {
7335 struct vm_area_struct *vma;
7337 const char *file_name;
7345 struct perf_event_header header;
7355 static int perf_event_mmap_match(struct perf_event *event,
7358 struct perf_mmap_event *mmap_event = data;
7359 struct vm_area_struct *vma = mmap_event->vma;
7360 int executable = vma->vm_flags & VM_EXEC;
7362 return (!executable && event->attr.mmap_data) ||
7363 (executable && (event->attr.mmap || event->attr.mmap2));
7366 static void perf_event_mmap_output(struct perf_event *event,
7369 struct perf_mmap_event *mmap_event = data;
7370 struct perf_output_handle handle;
7371 struct perf_sample_data sample;
7372 int size = mmap_event->event_id.header.size;
7373 u32 type = mmap_event->event_id.header.type;
7376 if (!perf_event_mmap_match(event, data))
7379 if (event->attr.mmap2) {
7380 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7381 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7382 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7383 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7384 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7385 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7386 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7389 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7390 ret = perf_output_begin(&handle, event,
7391 mmap_event->event_id.header.size);
7395 mmap_event->event_id.pid = perf_event_pid(event, current);
7396 mmap_event->event_id.tid = perf_event_tid(event, current);
7398 perf_output_put(&handle, mmap_event->event_id);
7400 if (event->attr.mmap2) {
7401 perf_output_put(&handle, mmap_event->maj);
7402 perf_output_put(&handle, mmap_event->min);
7403 perf_output_put(&handle, mmap_event->ino);
7404 perf_output_put(&handle, mmap_event->ino_generation);
7405 perf_output_put(&handle, mmap_event->prot);
7406 perf_output_put(&handle, mmap_event->flags);
7409 __output_copy(&handle, mmap_event->file_name,
7410 mmap_event->file_size);
7412 perf_event__output_id_sample(event, &handle, &sample);
7414 perf_output_end(&handle);
7416 mmap_event->event_id.header.size = size;
7417 mmap_event->event_id.header.type = type;
7420 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7422 struct vm_area_struct *vma = mmap_event->vma;
7423 struct file *file = vma->vm_file;
7424 int maj = 0, min = 0;
7425 u64 ino = 0, gen = 0;
7426 u32 prot = 0, flags = 0;
7432 if (vma->vm_flags & VM_READ)
7434 if (vma->vm_flags & VM_WRITE)
7436 if (vma->vm_flags & VM_EXEC)
7439 if (vma->vm_flags & VM_MAYSHARE)
7442 flags = MAP_PRIVATE;
7444 if (vma->vm_flags & VM_DENYWRITE)
7445 flags |= MAP_DENYWRITE;
7446 if (vma->vm_flags & VM_MAYEXEC)
7447 flags |= MAP_EXECUTABLE;
7448 if (vma->vm_flags & VM_LOCKED)
7449 flags |= MAP_LOCKED;
7450 if (vma->vm_flags & VM_HUGETLB)
7451 flags |= MAP_HUGETLB;
7454 struct inode *inode;
7457 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7463 * d_path() works from the end of the rb backwards, so we
7464 * need to add enough zero bytes after the string to handle
7465 * the 64bit alignment we do later.
7467 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7472 inode = file_inode(vma->vm_file);
7473 dev = inode->i_sb->s_dev;
7475 gen = inode->i_generation;
7481 if (vma->vm_ops && vma->vm_ops->name) {
7482 name = (char *) vma->vm_ops->name(vma);
7487 name = (char *)arch_vma_name(vma);
7491 if (vma->vm_start <= vma->vm_mm->start_brk &&
7492 vma->vm_end >= vma->vm_mm->brk) {
7496 if (vma->vm_start <= vma->vm_mm->start_stack &&
7497 vma->vm_end >= vma->vm_mm->start_stack) {
7507 strlcpy(tmp, name, sizeof(tmp));
7511 * Since our buffer works in 8 byte units we need to align our string
7512 * size to a multiple of 8. However, we must guarantee the tail end is
7513 * zero'd out to avoid leaking random bits to userspace.
7515 size = strlen(name)+1;
7516 while (!IS_ALIGNED(size, sizeof(u64)))
7517 name[size++] = '\0';
7519 mmap_event->file_name = name;
7520 mmap_event->file_size = size;
7521 mmap_event->maj = maj;
7522 mmap_event->min = min;
7523 mmap_event->ino = ino;
7524 mmap_event->ino_generation = gen;
7525 mmap_event->prot = prot;
7526 mmap_event->flags = flags;
7528 if (!(vma->vm_flags & VM_EXEC))
7529 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7531 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7533 perf_iterate_sb(perf_event_mmap_output,
7541 * Check whether inode and address range match filter criteria.
7543 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7544 struct file *file, unsigned long offset,
7547 /* d_inode(NULL) won't be equal to any mapped user-space file */
7548 if (!filter->path.dentry)
7551 if (d_inode(filter->path.dentry) != file_inode(file))
7554 if (filter->offset > offset + size)
7557 if (filter->offset + filter->size < offset)
7563 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7564 struct vm_area_struct *vma,
7565 struct perf_addr_filter_range *fr)
7567 unsigned long vma_size = vma->vm_end - vma->vm_start;
7568 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7569 struct file *file = vma->vm_file;
7571 if (!perf_addr_filter_match(filter, file, off, vma_size))
7574 if (filter->offset < off) {
7575 fr->start = vma->vm_start;
7576 fr->size = min(vma_size, filter->size - (off - filter->offset));
7578 fr->start = vma->vm_start + filter->offset - off;
7579 fr->size = min(vma->vm_end - fr->start, filter->size);
7585 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7587 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7588 struct vm_area_struct *vma = data;
7589 struct perf_addr_filter *filter;
7590 unsigned int restart = 0, count = 0;
7591 unsigned long flags;
7593 if (!has_addr_filter(event))
7599 raw_spin_lock_irqsave(&ifh->lock, flags);
7600 list_for_each_entry(filter, &ifh->list, entry) {
7601 if (perf_addr_filter_vma_adjust(filter, vma,
7602 &event->addr_filter_ranges[count]))
7609 event->addr_filters_gen++;
7610 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7613 perf_event_stop(event, 1);
7617 * Adjust all task's events' filters to the new vma
7619 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7621 struct perf_event_context *ctx;
7625 * Data tracing isn't supported yet and as such there is no need
7626 * to keep track of anything that isn't related to executable code:
7628 if (!(vma->vm_flags & VM_EXEC))
7632 for_each_task_context_nr(ctxn) {
7633 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7637 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7642 void perf_event_mmap(struct vm_area_struct *vma)
7644 struct perf_mmap_event mmap_event;
7646 if (!atomic_read(&nr_mmap_events))
7649 mmap_event = (struct perf_mmap_event){
7655 .type = PERF_RECORD_MMAP,
7656 .misc = PERF_RECORD_MISC_USER,
7661 .start = vma->vm_start,
7662 .len = vma->vm_end - vma->vm_start,
7663 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7665 /* .maj (attr_mmap2 only) */
7666 /* .min (attr_mmap2 only) */
7667 /* .ino (attr_mmap2 only) */
7668 /* .ino_generation (attr_mmap2 only) */
7669 /* .prot (attr_mmap2 only) */
7670 /* .flags (attr_mmap2 only) */
7673 perf_addr_filters_adjust(vma);
7674 perf_event_mmap_event(&mmap_event);
7677 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7678 unsigned long size, u64 flags)
7680 struct perf_output_handle handle;
7681 struct perf_sample_data sample;
7682 struct perf_aux_event {
7683 struct perf_event_header header;
7689 .type = PERF_RECORD_AUX,
7691 .size = sizeof(rec),
7699 perf_event_header__init_id(&rec.header, &sample, event);
7700 ret = perf_output_begin(&handle, event, rec.header.size);
7705 perf_output_put(&handle, rec);
7706 perf_event__output_id_sample(event, &handle, &sample);
7708 perf_output_end(&handle);
7712 * Lost/dropped samples logging
7714 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7716 struct perf_output_handle handle;
7717 struct perf_sample_data sample;
7721 struct perf_event_header header;
7723 } lost_samples_event = {
7725 .type = PERF_RECORD_LOST_SAMPLES,
7727 .size = sizeof(lost_samples_event),
7732 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7734 ret = perf_output_begin(&handle, event,
7735 lost_samples_event.header.size);
7739 perf_output_put(&handle, lost_samples_event);
7740 perf_event__output_id_sample(event, &handle, &sample);
7741 perf_output_end(&handle);
7745 * context_switch tracking
7748 struct perf_switch_event {
7749 struct task_struct *task;
7750 struct task_struct *next_prev;
7753 struct perf_event_header header;
7759 static int perf_event_switch_match(struct perf_event *event)
7761 return event->attr.context_switch;
7764 static void perf_event_switch_output(struct perf_event *event, void *data)
7766 struct perf_switch_event *se = data;
7767 struct perf_output_handle handle;
7768 struct perf_sample_data sample;
7771 if (!perf_event_switch_match(event))
7774 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7775 if (event->ctx->task) {
7776 se->event_id.header.type = PERF_RECORD_SWITCH;
7777 se->event_id.header.size = sizeof(se->event_id.header);
7779 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7780 se->event_id.header.size = sizeof(se->event_id);
7781 se->event_id.next_prev_pid =
7782 perf_event_pid(event, se->next_prev);
7783 se->event_id.next_prev_tid =
7784 perf_event_tid(event, se->next_prev);
7787 perf_event_header__init_id(&se->event_id.header, &sample, event);
7789 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7793 if (event->ctx->task)
7794 perf_output_put(&handle, se->event_id.header);
7796 perf_output_put(&handle, se->event_id);
7798 perf_event__output_id_sample(event, &handle, &sample);
7800 perf_output_end(&handle);
7803 static void perf_event_switch(struct task_struct *task,
7804 struct task_struct *next_prev, bool sched_in)
7806 struct perf_switch_event switch_event;
7808 /* N.B. caller checks nr_switch_events != 0 */
7810 switch_event = (struct perf_switch_event){
7812 .next_prev = next_prev,
7816 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7819 /* .next_prev_pid */
7820 /* .next_prev_tid */
7824 if (!sched_in && task->state == TASK_RUNNING)
7825 switch_event.event_id.header.misc |=
7826 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7828 perf_iterate_sb(perf_event_switch_output,
7834 * IRQ throttle logging
7837 static void perf_log_throttle(struct perf_event *event, int enable)
7839 struct perf_output_handle handle;
7840 struct perf_sample_data sample;
7844 struct perf_event_header header;
7848 } throttle_event = {
7850 .type = PERF_RECORD_THROTTLE,
7852 .size = sizeof(throttle_event),
7854 .time = perf_event_clock(event),
7855 .id = primary_event_id(event),
7856 .stream_id = event->id,
7860 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7862 perf_event_header__init_id(&throttle_event.header, &sample, event);
7864 ret = perf_output_begin(&handle, event,
7865 throttle_event.header.size);
7869 perf_output_put(&handle, throttle_event);
7870 perf_event__output_id_sample(event, &handle, &sample);
7871 perf_output_end(&handle);
7875 * ksymbol register/unregister tracking
7878 struct perf_ksymbol_event {
7882 struct perf_event_header header;
7890 static int perf_event_ksymbol_match(struct perf_event *event)
7892 return event->attr.ksymbol;
7895 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7897 struct perf_ksymbol_event *ksymbol_event = data;
7898 struct perf_output_handle handle;
7899 struct perf_sample_data sample;
7902 if (!perf_event_ksymbol_match(event))
7905 perf_event_header__init_id(&ksymbol_event->event_id.header,
7907 ret = perf_output_begin(&handle, event,
7908 ksymbol_event->event_id.header.size);
7912 perf_output_put(&handle, ksymbol_event->event_id);
7913 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7914 perf_event__output_id_sample(event, &handle, &sample);
7916 perf_output_end(&handle);
7919 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7922 struct perf_ksymbol_event ksymbol_event;
7923 char name[KSYM_NAME_LEN];
7927 if (!atomic_read(&nr_ksymbol_events))
7930 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7931 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7934 strlcpy(name, sym, KSYM_NAME_LEN);
7935 name_len = strlen(name) + 1;
7936 while (!IS_ALIGNED(name_len, sizeof(u64)))
7937 name[name_len++] = '\0';
7938 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7941 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7943 ksymbol_event = (struct perf_ksymbol_event){
7945 .name_len = name_len,
7948 .type = PERF_RECORD_KSYMBOL,
7949 .size = sizeof(ksymbol_event.event_id) +
7954 .ksym_type = ksym_type,
7959 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7962 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7966 * bpf program load/unload tracking
7969 struct perf_bpf_event {
7970 struct bpf_prog *prog;
7972 struct perf_event_header header;
7976 u8 tag[BPF_TAG_SIZE];
7980 static int perf_event_bpf_match(struct perf_event *event)
7982 return event->attr.bpf_event;
7985 static void perf_event_bpf_output(struct perf_event *event, void *data)
7987 struct perf_bpf_event *bpf_event = data;
7988 struct perf_output_handle handle;
7989 struct perf_sample_data sample;
7992 if (!perf_event_bpf_match(event))
7995 perf_event_header__init_id(&bpf_event->event_id.header,
7997 ret = perf_output_begin(&handle, event,
7998 bpf_event->event_id.header.size);
8002 perf_output_put(&handle, bpf_event->event_id);
8003 perf_event__output_id_sample(event, &handle, &sample);
8005 perf_output_end(&handle);
8008 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8009 enum perf_bpf_event_type type)
8011 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8012 char sym[KSYM_NAME_LEN];
8015 if (prog->aux->func_cnt == 0) {
8016 bpf_get_prog_name(prog, sym);
8017 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8018 (u64)(unsigned long)prog->bpf_func,
8019 prog->jited_len, unregister, sym);
8021 for (i = 0; i < prog->aux->func_cnt; i++) {
8022 struct bpf_prog *subprog = prog->aux->func[i];
8024 bpf_get_prog_name(subprog, sym);
8026 PERF_RECORD_KSYMBOL_TYPE_BPF,
8027 (u64)(unsigned long)subprog->bpf_func,
8028 subprog->jited_len, unregister, sym);
8033 void perf_event_bpf_event(struct bpf_prog *prog,
8034 enum perf_bpf_event_type type,
8037 struct perf_bpf_event bpf_event;
8039 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8040 type >= PERF_BPF_EVENT_MAX)
8044 case PERF_BPF_EVENT_PROG_LOAD:
8045 case PERF_BPF_EVENT_PROG_UNLOAD:
8046 if (atomic_read(&nr_ksymbol_events))
8047 perf_event_bpf_emit_ksymbols(prog, type);
8053 if (!atomic_read(&nr_bpf_events))
8056 bpf_event = (struct perf_bpf_event){
8060 .type = PERF_RECORD_BPF_EVENT,
8061 .size = sizeof(bpf_event.event_id),
8065 .id = prog->aux->id,
8069 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8071 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8072 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8075 void perf_event_itrace_started(struct perf_event *event)
8077 event->attach_state |= PERF_ATTACH_ITRACE;
8080 static void perf_log_itrace_start(struct perf_event *event)
8082 struct perf_output_handle handle;
8083 struct perf_sample_data sample;
8084 struct perf_aux_event {
8085 struct perf_event_header header;
8092 event = event->parent;
8094 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8095 event->attach_state & PERF_ATTACH_ITRACE)
8098 rec.header.type = PERF_RECORD_ITRACE_START;
8099 rec.header.misc = 0;
8100 rec.header.size = sizeof(rec);
8101 rec.pid = perf_event_pid(event, current);
8102 rec.tid = perf_event_tid(event, current);
8104 perf_event_header__init_id(&rec.header, &sample, event);
8105 ret = perf_output_begin(&handle, event, rec.header.size);
8110 perf_output_put(&handle, rec);
8111 perf_event__output_id_sample(event, &handle, &sample);
8113 perf_output_end(&handle);
8117 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8119 struct hw_perf_event *hwc = &event->hw;
8123 seq = __this_cpu_read(perf_throttled_seq);
8124 if (seq != hwc->interrupts_seq) {
8125 hwc->interrupts_seq = seq;
8126 hwc->interrupts = 1;
8129 if (unlikely(throttle
8130 && hwc->interrupts >= max_samples_per_tick)) {
8131 __this_cpu_inc(perf_throttled_count);
8132 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8133 hwc->interrupts = MAX_INTERRUPTS;
8134 perf_log_throttle(event, 0);
8139 if (event->attr.freq) {
8140 u64 now = perf_clock();
8141 s64 delta = now - hwc->freq_time_stamp;
8143 hwc->freq_time_stamp = now;
8145 if (delta > 0 && delta < 2*TICK_NSEC)
8146 perf_adjust_period(event, delta, hwc->last_period, true);
8152 int perf_event_account_interrupt(struct perf_event *event)
8154 return __perf_event_account_interrupt(event, 1);
8158 * Generic event overflow handling, sampling.
8161 static int __perf_event_overflow(struct perf_event *event,
8162 int throttle, struct perf_sample_data *data,
8163 struct pt_regs *regs)
8165 int events = atomic_read(&event->event_limit);
8169 * Non-sampling counters might still use the PMI to fold short
8170 * hardware counters, ignore those.
8172 if (unlikely(!is_sampling_event(event)))
8175 ret = __perf_event_account_interrupt(event, throttle);
8178 * XXX event_limit might not quite work as expected on inherited
8182 event->pending_kill = POLL_IN;
8183 if (events && atomic_dec_and_test(&event->event_limit)) {
8185 event->pending_kill = POLL_HUP;
8187 perf_event_disable_inatomic(event);
8190 READ_ONCE(event->overflow_handler)(event, data, regs);
8192 if (*perf_event_fasync(event) && event->pending_kill) {
8193 event->pending_wakeup = 1;
8194 irq_work_queue(&event->pending);
8200 int perf_event_overflow(struct perf_event *event,
8201 struct perf_sample_data *data,
8202 struct pt_regs *regs)
8204 return __perf_event_overflow(event, 1, data, regs);
8208 * Generic software event infrastructure
8211 struct swevent_htable {
8212 struct swevent_hlist *swevent_hlist;
8213 struct mutex hlist_mutex;
8216 /* Recursion avoidance in each contexts */
8217 int recursion[PERF_NR_CONTEXTS];
8220 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8223 * We directly increment event->count and keep a second value in
8224 * event->hw.period_left to count intervals. This period event
8225 * is kept in the range [-sample_period, 0] so that we can use the
8229 u64 perf_swevent_set_period(struct perf_event *event)
8231 struct hw_perf_event *hwc = &event->hw;
8232 u64 period = hwc->last_period;
8236 hwc->last_period = hwc->sample_period;
8239 old = val = local64_read(&hwc->period_left);
8243 nr = div64_u64(period + val, period);
8244 offset = nr * period;
8246 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8252 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8253 struct perf_sample_data *data,
8254 struct pt_regs *regs)
8256 struct hw_perf_event *hwc = &event->hw;
8260 overflow = perf_swevent_set_period(event);
8262 if (hwc->interrupts == MAX_INTERRUPTS)
8265 for (; overflow; overflow--) {
8266 if (__perf_event_overflow(event, throttle,
8269 * We inhibit the overflow from happening when
8270 * hwc->interrupts == MAX_INTERRUPTS.
8278 static void perf_swevent_event(struct perf_event *event, u64 nr,
8279 struct perf_sample_data *data,
8280 struct pt_regs *regs)
8282 struct hw_perf_event *hwc = &event->hw;
8284 local64_add(nr, &event->count);
8289 if (!is_sampling_event(event))
8292 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8294 return perf_swevent_overflow(event, 1, data, regs);
8296 data->period = event->hw.last_period;
8298 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8299 return perf_swevent_overflow(event, 1, data, regs);
8301 if (local64_add_negative(nr, &hwc->period_left))
8304 perf_swevent_overflow(event, 0, data, regs);
8307 static int perf_exclude_event(struct perf_event *event,
8308 struct pt_regs *regs)
8310 if (event->hw.state & PERF_HES_STOPPED)
8314 if (event->attr.exclude_user && user_mode(regs))
8317 if (event->attr.exclude_kernel && !user_mode(regs))
8324 static int perf_swevent_match(struct perf_event *event,
8325 enum perf_type_id type,
8327 struct perf_sample_data *data,
8328 struct pt_regs *regs)
8330 if (event->attr.type != type)
8333 if (event->attr.config != event_id)
8336 if (perf_exclude_event(event, regs))
8342 static inline u64 swevent_hash(u64 type, u32 event_id)
8344 u64 val = event_id | (type << 32);
8346 return hash_64(val, SWEVENT_HLIST_BITS);
8349 static inline struct hlist_head *
8350 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8352 u64 hash = swevent_hash(type, event_id);
8354 return &hlist->heads[hash];
8357 /* For the read side: events when they trigger */
8358 static inline struct hlist_head *
8359 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8361 struct swevent_hlist *hlist;
8363 hlist = rcu_dereference(swhash->swevent_hlist);
8367 return __find_swevent_head(hlist, type, event_id);
8370 /* For the event head insertion and removal in the hlist */
8371 static inline struct hlist_head *
8372 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8374 struct swevent_hlist *hlist;
8375 u32 event_id = event->attr.config;
8376 u64 type = event->attr.type;
8379 * Event scheduling is always serialized against hlist allocation
8380 * and release. Which makes the protected version suitable here.
8381 * The context lock guarantees that.
8383 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8384 lockdep_is_held(&event->ctx->lock));
8388 return __find_swevent_head(hlist, type, event_id);
8391 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8393 struct perf_sample_data *data,
8394 struct pt_regs *regs)
8396 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8397 struct perf_event *event;
8398 struct hlist_head *head;
8401 head = find_swevent_head_rcu(swhash, type, event_id);
8405 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8406 if (perf_swevent_match(event, type, event_id, data, regs))
8407 perf_swevent_event(event, nr, data, regs);
8413 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8415 int perf_swevent_get_recursion_context(void)
8417 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8419 return get_recursion_context(swhash->recursion);
8421 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8423 void perf_swevent_put_recursion_context(int rctx)
8425 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8427 put_recursion_context(swhash->recursion, rctx);
8430 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8432 struct perf_sample_data data;
8434 if (WARN_ON_ONCE(!regs))
8437 perf_sample_data_init(&data, addr, 0);
8438 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8441 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8445 preempt_disable_notrace();
8446 rctx = perf_swevent_get_recursion_context();
8447 if (unlikely(rctx < 0))
8450 ___perf_sw_event(event_id, nr, regs, addr);
8452 perf_swevent_put_recursion_context(rctx);
8454 preempt_enable_notrace();
8457 static void perf_swevent_read(struct perf_event *event)
8461 static int perf_swevent_add(struct perf_event *event, int flags)
8463 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8464 struct hw_perf_event *hwc = &event->hw;
8465 struct hlist_head *head;
8467 if (is_sampling_event(event)) {
8468 hwc->last_period = hwc->sample_period;
8469 perf_swevent_set_period(event);
8472 hwc->state = !(flags & PERF_EF_START);
8474 head = find_swevent_head(swhash, event);
8475 if (WARN_ON_ONCE(!head))
8478 hlist_add_head_rcu(&event->hlist_entry, head);
8479 perf_event_update_userpage(event);
8484 static void perf_swevent_del(struct perf_event *event, int flags)
8486 hlist_del_rcu(&event->hlist_entry);
8489 static void perf_swevent_start(struct perf_event *event, int flags)
8491 event->hw.state = 0;
8494 static void perf_swevent_stop(struct perf_event *event, int flags)
8496 event->hw.state = PERF_HES_STOPPED;
8499 /* Deref the hlist from the update side */
8500 static inline struct swevent_hlist *
8501 swevent_hlist_deref(struct swevent_htable *swhash)
8503 return rcu_dereference_protected(swhash->swevent_hlist,
8504 lockdep_is_held(&swhash->hlist_mutex));
8507 static void swevent_hlist_release(struct swevent_htable *swhash)
8509 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8514 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8515 kfree_rcu(hlist, rcu_head);
8518 static void swevent_hlist_put_cpu(int cpu)
8520 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8522 mutex_lock(&swhash->hlist_mutex);
8524 if (!--swhash->hlist_refcount)
8525 swevent_hlist_release(swhash);
8527 mutex_unlock(&swhash->hlist_mutex);
8530 static void swevent_hlist_put(void)
8534 for_each_possible_cpu(cpu)
8535 swevent_hlist_put_cpu(cpu);
8538 static int swevent_hlist_get_cpu(int cpu)
8540 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8543 mutex_lock(&swhash->hlist_mutex);
8544 if (!swevent_hlist_deref(swhash) &&
8545 cpumask_test_cpu(cpu, perf_online_mask)) {
8546 struct swevent_hlist *hlist;
8548 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8553 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8555 swhash->hlist_refcount++;
8557 mutex_unlock(&swhash->hlist_mutex);
8562 static int swevent_hlist_get(void)
8564 int err, cpu, failed_cpu;
8566 mutex_lock(&pmus_lock);
8567 for_each_possible_cpu(cpu) {
8568 err = swevent_hlist_get_cpu(cpu);
8574 mutex_unlock(&pmus_lock);
8577 for_each_possible_cpu(cpu) {
8578 if (cpu == failed_cpu)
8580 swevent_hlist_put_cpu(cpu);
8582 mutex_unlock(&pmus_lock);
8586 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8588 static void sw_perf_event_destroy(struct perf_event *event)
8590 u64 event_id = event->attr.config;
8592 WARN_ON(event->parent);
8594 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8595 swevent_hlist_put();
8598 static int perf_swevent_init(struct perf_event *event)
8600 u64 event_id = event->attr.config;
8602 if (event->attr.type != PERF_TYPE_SOFTWARE)
8606 * no branch sampling for software events
8608 if (has_branch_stack(event))
8612 case PERF_COUNT_SW_CPU_CLOCK:
8613 case PERF_COUNT_SW_TASK_CLOCK:
8620 if (event_id >= PERF_COUNT_SW_MAX)
8623 if (!event->parent) {
8626 err = swevent_hlist_get();
8630 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8631 event->destroy = sw_perf_event_destroy;
8637 static struct pmu perf_swevent = {
8638 .task_ctx_nr = perf_sw_context,
8640 .capabilities = PERF_PMU_CAP_NO_NMI,
8642 .event_init = perf_swevent_init,
8643 .add = perf_swevent_add,
8644 .del = perf_swevent_del,
8645 .start = perf_swevent_start,
8646 .stop = perf_swevent_stop,
8647 .read = perf_swevent_read,
8650 #ifdef CONFIG_EVENT_TRACING
8652 static int perf_tp_filter_match(struct perf_event *event,
8653 struct perf_sample_data *data)
8655 void *record = data->raw->frag.data;
8657 /* only top level events have filters set */
8659 event = event->parent;
8661 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8666 static int perf_tp_event_match(struct perf_event *event,
8667 struct perf_sample_data *data,
8668 struct pt_regs *regs)
8670 if (event->hw.state & PERF_HES_STOPPED)
8673 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8675 if (event->attr.exclude_kernel && !user_mode(regs))
8678 if (!perf_tp_filter_match(event, data))
8684 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8685 struct trace_event_call *call, u64 count,
8686 struct pt_regs *regs, struct hlist_head *head,
8687 struct task_struct *task)
8689 if (bpf_prog_array_valid(call)) {
8690 *(struct pt_regs **)raw_data = regs;
8691 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8692 perf_swevent_put_recursion_context(rctx);
8696 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8699 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8701 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8702 struct pt_regs *regs, struct hlist_head *head, int rctx,
8703 struct task_struct *task)
8705 struct perf_sample_data data;
8706 struct perf_event *event;
8708 struct perf_raw_record raw = {
8715 perf_sample_data_init(&data, 0, 0);
8718 perf_trace_buf_update(record, event_type);
8720 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8721 if (perf_tp_event_match(event, &data, regs))
8722 perf_swevent_event(event, count, &data, regs);
8726 * If we got specified a target task, also iterate its context and
8727 * deliver this event there too.
8729 if (task && task != current) {
8730 struct perf_event_context *ctx;
8731 struct trace_entry *entry = record;
8734 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8738 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8739 if (event->cpu != smp_processor_id())
8741 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8743 if (event->attr.config != entry->type)
8745 if (perf_tp_event_match(event, &data, regs))
8746 perf_swevent_event(event, count, &data, regs);
8752 perf_swevent_put_recursion_context(rctx);
8754 EXPORT_SYMBOL_GPL(perf_tp_event);
8756 static void tp_perf_event_destroy(struct perf_event *event)
8758 perf_trace_destroy(event);
8761 static int perf_tp_event_init(struct perf_event *event)
8765 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8769 * no branch sampling for tracepoint events
8771 if (has_branch_stack(event))
8774 err = perf_trace_init(event);
8778 event->destroy = tp_perf_event_destroy;
8783 static struct pmu perf_tracepoint = {
8784 .task_ctx_nr = perf_sw_context,
8786 .event_init = perf_tp_event_init,
8787 .add = perf_trace_add,
8788 .del = perf_trace_del,
8789 .start = perf_swevent_start,
8790 .stop = perf_swevent_stop,
8791 .read = perf_swevent_read,
8794 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8796 * Flags in config, used by dynamic PMU kprobe and uprobe
8797 * The flags should match following PMU_FORMAT_ATTR().
8799 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8800 * if not set, create kprobe/uprobe
8802 * The following values specify a reference counter (or semaphore in the
8803 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8804 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8806 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8807 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8809 enum perf_probe_config {
8810 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8811 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8812 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8815 PMU_FORMAT_ATTR(retprobe, "config:0");
8818 #ifdef CONFIG_KPROBE_EVENTS
8819 static struct attribute *kprobe_attrs[] = {
8820 &format_attr_retprobe.attr,
8824 static struct attribute_group kprobe_format_group = {
8826 .attrs = kprobe_attrs,
8829 static const struct attribute_group *kprobe_attr_groups[] = {
8830 &kprobe_format_group,
8834 static int perf_kprobe_event_init(struct perf_event *event);
8835 static struct pmu perf_kprobe = {
8836 .task_ctx_nr = perf_sw_context,
8837 .event_init = perf_kprobe_event_init,
8838 .add = perf_trace_add,
8839 .del = perf_trace_del,
8840 .start = perf_swevent_start,
8841 .stop = perf_swevent_stop,
8842 .read = perf_swevent_read,
8843 .attr_groups = kprobe_attr_groups,
8846 static int perf_kprobe_event_init(struct perf_event *event)
8851 if (event->attr.type != perf_kprobe.type)
8854 if (!capable(CAP_SYS_ADMIN))
8858 * no branch sampling for probe events
8860 if (has_branch_stack(event))
8863 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8864 err = perf_kprobe_init(event, is_retprobe);
8868 event->destroy = perf_kprobe_destroy;
8872 #endif /* CONFIG_KPROBE_EVENTS */
8874 #ifdef CONFIG_UPROBE_EVENTS
8875 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8877 static struct attribute *uprobe_attrs[] = {
8878 &format_attr_retprobe.attr,
8879 &format_attr_ref_ctr_offset.attr,
8883 static struct attribute_group uprobe_format_group = {
8885 .attrs = uprobe_attrs,
8888 static const struct attribute_group *uprobe_attr_groups[] = {
8889 &uprobe_format_group,
8893 static int perf_uprobe_event_init(struct perf_event *event);
8894 static struct pmu perf_uprobe = {
8895 .task_ctx_nr = perf_sw_context,
8896 .event_init = perf_uprobe_event_init,
8897 .add = perf_trace_add,
8898 .del = perf_trace_del,
8899 .start = perf_swevent_start,
8900 .stop = perf_swevent_stop,
8901 .read = perf_swevent_read,
8902 .attr_groups = uprobe_attr_groups,
8905 static int perf_uprobe_event_init(struct perf_event *event)
8908 unsigned long ref_ctr_offset;
8911 if (event->attr.type != perf_uprobe.type)
8914 if (!capable(CAP_SYS_ADMIN))
8918 * no branch sampling for probe events
8920 if (has_branch_stack(event))
8923 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8924 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8925 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8929 event->destroy = perf_uprobe_destroy;
8933 #endif /* CONFIG_UPROBE_EVENTS */
8935 static inline void perf_tp_register(void)
8937 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8938 #ifdef CONFIG_KPROBE_EVENTS
8939 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8941 #ifdef CONFIG_UPROBE_EVENTS
8942 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8946 static void perf_event_free_filter(struct perf_event *event)
8948 ftrace_profile_free_filter(event);
8951 #ifdef CONFIG_BPF_SYSCALL
8952 static void bpf_overflow_handler(struct perf_event *event,
8953 struct perf_sample_data *data,
8954 struct pt_regs *regs)
8956 struct bpf_perf_event_data_kern ctx = {
8962 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8964 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8967 ret = BPF_PROG_RUN(event->prog, &ctx);
8970 __this_cpu_dec(bpf_prog_active);
8975 event->orig_overflow_handler(event, data, regs);
8978 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8980 struct bpf_prog *prog;
8982 if (event->overflow_handler_context)
8983 /* hw breakpoint or kernel counter */
8989 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8991 return PTR_ERR(prog);
8994 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8995 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8999 static void perf_event_free_bpf_handler(struct perf_event *event)
9001 struct bpf_prog *prog = event->prog;
9006 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9011 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9015 static void perf_event_free_bpf_handler(struct perf_event *event)
9021 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9022 * with perf_event_open()
9024 static inline bool perf_event_is_tracing(struct perf_event *event)
9026 if (event->pmu == &perf_tracepoint)
9028 #ifdef CONFIG_KPROBE_EVENTS
9029 if (event->pmu == &perf_kprobe)
9032 #ifdef CONFIG_UPROBE_EVENTS
9033 if (event->pmu == &perf_uprobe)
9039 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9041 bool is_kprobe, is_tracepoint, is_syscall_tp;
9042 struct bpf_prog *prog;
9045 if (!perf_event_is_tracing(event))
9046 return perf_event_set_bpf_handler(event, prog_fd);
9048 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9049 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9050 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9051 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9052 /* bpf programs can only be attached to u/kprobe or tracepoint */
9055 prog = bpf_prog_get(prog_fd);
9057 return PTR_ERR(prog);
9059 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9060 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9061 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9062 /* valid fd, but invalid bpf program type */
9067 /* Kprobe override only works for kprobes, not uprobes. */
9068 if (prog->kprobe_override &&
9069 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9074 if (is_tracepoint || is_syscall_tp) {
9075 int off = trace_event_get_offsets(event->tp_event);
9077 if (prog->aux->max_ctx_offset > off) {
9083 ret = perf_event_attach_bpf_prog(event, prog);
9089 static void perf_event_free_bpf_prog(struct perf_event *event)
9091 if (!perf_event_is_tracing(event)) {
9092 perf_event_free_bpf_handler(event);
9095 perf_event_detach_bpf_prog(event);
9100 static inline void perf_tp_register(void)
9104 static void perf_event_free_filter(struct perf_event *event)
9108 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9113 static void perf_event_free_bpf_prog(struct perf_event *event)
9116 #endif /* CONFIG_EVENT_TRACING */
9118 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9119 void perf_bp_event(struct perf_event *bp, void *data)
9121 struct perf_sample_data sample;
9122 struct pt_regs *regs = data;
9124 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9126 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9127 perf_swevent_event(bp, 1, &sample, regs);
9132 * Allocate a new address filter
9134 static struct perf_addr_filter *
9135 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9137 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9138 struct perf_addr_filter *filter;
9140 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9144 INIT_LIST_HEAD(&filter->entry);
9145 list_add_tail(&filter->entry, filters);
9150 static void free_filters_list(struct list_head *filters)
9152 struct perf_addr_filter *filter, *iter;
9154 list_for_each_entry_safe(filter, iter, filters, entry) {
9155 path_put(&filter->path);
9156 list_del(&filter->entry);
9162 * Free existing address filters and optionally install new ones
9164 static void perf_addr_filters_splice(struct perf_event *event,
9165 struct list_head *head)
9167 unsigned long flags;
9170 if (!has_addr_filter(event))
9173 /* don't bother with children, they don't have their own filters */
9177 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9179 list_splice_init(&event->addr_filters.list, &list);
9181 list_splice(head, &event->addr_filters.list);
9183 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9185 free_filters_list(&list);
9189 * Scan through mm's vmas and see if one of them matches the
9190 * @filter; if so, adjust filter's address range.
9191 * Called with mm::mmap_sem down for reading.
9193 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9194 struct mm_struct *mm,
9195 struct perf_addr_filter_range *fr)
9197 struct vm_area_struct *vma;
9199 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9203 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9209 * Update event's address range filters based on the
9210 * task's existing mappings, if any.
9212 static void perf_event_addr_filters_apply(struct perf_event *event)
9214 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9215 struct task_struct *task = READ_ONCE(event->ctx->task);
9216 struct perf_addr_filter *filter;
9217 struct mm_struct *mm = NULL;
9218 unsigned int count = 0;
9219 unsigned long flags;
9222 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9223 * will stop on the parent's child_mutex that our caller is also holding
9225 if (task == TASK_TOMBSTONE)
9228 if (ifh->nr_file_filters) {
9229 mm = get_task_mm(event->ctx->task);
9233 down_read(&mm->mmap_sem);
9236 raw_spin_lock_irqsave(&ifh->lock, flags);
9237 list_for_each_entry(filter, &ifh->list, entry) {
9238 if (filter->path.dentry) {
9240 * Adjust base offset if the filter is associated to a
9241 * binary that needs to be mapped:
9243 event->addr_filter_ranges[count].start = 0;
9244 event->addr_filter_ranges[count].size = 0;
9246 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9248 event->addr_filter_ranges[count].start = filter->offset;
9249 event->addr_filter_ranges[count].size = filter->size;
9255 event->addr_filters_gen++;
9256 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9258 if (ifh->nr_file_filters) {
9259 up_read(&mm->mmap_sem);
9265 perf_event_stop(event, 1);
9269 * Address range filtering: limiting the data to certain
9270 * instruction address ranges. Filters are ioctl()ed to us from
9271 * userspace as ascii strings.
9273 * Filter string format:
9276 * where ACTION is one of the
9277 * * "filter": limit the trace to this region
9278 * * "start": start tracing from this address
9279 * * "stop": stop tracing at this address/region;
9281 * * for kernel addresses: <start address>[/<size>]
9282 * * for object files: <start address>[/<size>]@</path/to/object/file>
9284 * if <size> is not specified or is zero, the range is treated as a single
9285 * address; not valid for ACTION=="filter".
9299 IF_STATE_ACTION = 0,
9304 static const match_table_t if_tokens = {
9305 { IF_ACT_FILTER, "filter" },
9306 { IF_ACT_START, "start" },
9307 { IF_ACT_STOP, "stop" },
9308 { IF_SRC_FILE, "%u/%u@%s" },
9309 { IF_SRC_KERNEL, "%u/%u" },
9310 { IF_SRC_FILEADDR, "%u@%s" },
9311 { IF_SRC_KERNELADDR, "%u" },
9312 { IF_ACT_NONE, NULL },
9316 * Address filter string parser
9319 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9320 struct list_head *filters)
9322 struct perf_addr_filter *filter = NULL;
9323 char *start, *orig, *filename = NULL;
9324 substring_t args[MAX_OPT_ARGS];
9325 int state = IF_STATE_ACTION, token;
9326 unsigned int kernel = 0;
9329 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9333 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9334 static const enum perf_addr_filter_action_t actions[] = {
9335 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9336 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9337 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9344 /* filter definition begins */
9345 if (state == IF_STATE_ACTION) {
9346 filter = perf_addr_filter_new(event, filters);
9351 token = match_token(start, if_tokens, args);
9356 if (state != IF_STATE_ACTION)
9359 filter->action = actions[token];
9360 state = IF_STATE_SOURCE;
9363 case IF_SRC_KERNELADDR:
9368 case IF_SRC_FILEADDR:
9370 if (state != IF_STATE_SOURCE)
9374 ret = kstrtoul(args[0].from, 0, &filter->offset);
9378 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9380 ret = kstrtoul(args[1].from, 0, &filter->size);
9385 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9386 int fpos = token == IF_SRC_FILE ? 2 : 1;
9388 filename = match_strdup(&args[fpos]);
9395 state = IF_STATE_END;
9403 * Filter definition is fully parsed, validate and install it.
9404 * Make sure that it doesn't contradict itself or the event's
9407 if (state == IF_STATE_END) {
9409 if (kernel && event->attr.exclude_kernel)
9413 * ACTION "filter" must have a non-zero length region
9416 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9425 * For now, we only support file-based filters
9426 * in per-task events; doing so for CPU-wide
9427 * events requires additional context switching
9428 * trickery, since same object code will be
9429 * mapped at different virtual addresses in
9430 * different processes.
9433 if (!event->ctx->task)
9434 goto fail_free_name;
9436 /* look up the path and grab its inode */
9437 ret = kern_path(filename, LOOKUP_FOLLOW,
9440 goto fail_free_name;
9446 if (!filter->path.dentry ||
9447 !S_ISREG(d_inode(filter->path.dentry)
9451 event->addr_filters.nr_file_filters++;
9454 /* ready to consume more filters */
9455 state = IF_STATE_ACTION;
9460 if (state != IF_STATE_ACTION)
9470 free_filters_list(filters);
9477 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9483 * Since this is called in perf_ioctl() path, we're already holding
9486 lockdep_assert_held(&event->ctx->mutex);
9488 if (WARN_ON_ONCE(event->parent))
9491 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9493 goto fail_clear_files;
9495 ret = event->pmu->addr_filters_validate(&filters);
9497 goto fail_free_filters;
9499 /* remove existing filters, if any */
9500 perf_addr_filters_splice(event, &filters);
9502 /* install new filters */
9503 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9508 free_filters_list(&filters);
9511 event->addr_filters.nr_file_filters = 0;
9516 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9521 filter_str = strndup_user(arg, PAGE_SIZE);
9522 if (IS_ERR(filter_str))
9523 return PTR_ERR(filter_str);
9525 #ifdef CONFIG_EVENT_TRACING
9526 if (perf_event_is_tracing(event)) {
9527 struct perf_event_context *ctx = event->ctx;
9530 * Beware, here be dragons!!
9532 * the tracepoint muck will deadlock against ctx->mutex, but
9533 * the tracepoint stuff does not actually need it. So
9534 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9535 * already have a reference on ctx.
9537 * This can result in event getting moved to a different ctx,
9538 * but that does not affect the tracepoint state.
9540 mutex_unlock(&ctx->mutex);
9541 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9542 mutex_lock(&ctx->mutex);
9545 if (has_addr_filter(event))
9546 ret = perf_event_set_addr_filter(event, filter_str);
9553 * hrtimer based swevent callback
9556 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9558 enum hrtimer_restart ret = HRTIMER_RESTART;
9559 struct perf_sample_data data;
9560 struct pt_regs *regs;
9561 struct perf_event *event;
9564 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9566 if (event->state != PERF_EVENT_STATE_ACTIVE)
9567 return HRTIMER_NORESTART;
9569 event->pmu->read(event);
9571 perf_sample_data_init(&data, 0, event->hw.last_period);
9572 regs = get_irq_regs();
9574 if (regs && !perf_exclude_event(event, regs)) {
9575 if (!(event->attr.exclude_idle && is_idle_task(current)))
9576 if (__perf_event_overflow(event, 1, &data, regs))
9577 ret = HRTIMER_NORESTART;
9580 period = max_t(u64, 10000, event->hw.sample_period);
9581 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9586 static void perf_swevent_start_hrtimer(struct perf_event *event)
9588 struct hw_perf_event *hwc = &event->hw;
9591 if (!is_sampling_event(event))
9594 period = local64_read(&hwc->period_left);
9599 local64_set(&hwc->period_left, 0);
9601 period = max_t(u64, 10000, hwc->sample_period);
9603 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9604 HRTIMER_MODE_REL_PINNED_HARD);
9607 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9609 struct hw_perf_event *hwc = &event->hw;
9611 if (is_sampling_event(event)) {
9612 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9613 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9615 hrtimer_cancel(&hwc->hrtimer);
9619 static void perf_swevent_init_hrtimer(struct perf_event *event)
9621 struct hw_perf_event *hwc = &event->hw;
9623 if (!is_sampling_event(event))
9626 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
9627 hwc->hrtimer.function = perf_swevent_hrtimer;
9630 * Since hrtimers have a fixed rate, we can do a static freq->period
9631 * mapping and avoid the whole period adjust feedback stuff.
9633 if (event->attr.freq) {
9634 long freq = event->attr.sample_freq;
9636 event->attr.sample_period = NSEC_PER_SEC / freq;
9637 hwc->sample_period = event->attr.sample_period;
9638 local64_set(&hwc->period_left, hwc->sample_period);
9639 hwc->last_period = hwc->sample_period;
9640 event->attr.freq = 0;
9645 * Software event: cpu wall time clock
9648 static void cpu_clock_event_update(struct perf_event *event)
9653 now = local_clock();
9654 prev = local64_xchg(&event->hw.prev_count, now);
9655 local64_add(now - prev, &event->count);
9658 static void cpu_clock_event_start(struct perf_event *event, int flags)
9660 local64_set(&event->hw.prev_count, local_clock());
9661 perf_swevent_start_hrtimer(event);
9664 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9666 perf_swevent_cancel_hrtimer(event);
9667 cpu_clock_event_update(event);
9670 static int cpu_clock_event_add(struct perf_event *event, int flags)
9672 if (flags & PERF_EF_START)
9673 cpu_clock_event_start(event, flags);
9674 perf_event_update_userpage(event);
9679 static void cpu_clock_event_del(struct perf_event *event, int flags)
9681 cpu_clock_event_stop(event, flags);
9684 static void cpu_clock_event_read(struct perf_event *event)
9686 cpu_clock_event_update(event);
9689 static int cpu_clock_event_init(struct perf_event *event)
9691 if (event->attr.type != PERF_TYPE_SOFTWARE)
9694 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9698 * no branch sampling for software events
9700 if (has_branch_stack(event))
9703 perf_swevent_init_hrtimer(event);
9708 static struct pmu perf_cpu_clock = {
9709 .task_ctx_nr = perf_sw_context,
9711 .capabilities = PERF_PMU_CAP_NO_NMI,
9713 .event_init = cpu_clock_event_init,
9714 .add = cpu_clock_event_add,
9715 .del = cpu_clock_event_del,
9716 .start = cpu_clock_event_start,
9717 .stop = cpu_clock_event_stop,
9718 .read = cpu_clock_event_read,
9722 * Software event: task time clock
9725 static void task_clock_event_update(struct perf_event *event, u64 now)
9730 prev = local64_xchg(&event->hw.prev_count, now);
9732 local64_add(delta, &event->count);
9735 static void task_clock_event_start(struct perf_event *event, int flags)
9737 local64_set(&event->hw.prev_count, event->ctx->time);
9738 perf_swevent_start_hrtimer(event);
9741 static void task_clock_event_stop(struct perf_event *event, int flags)
9743 perf_swevent_cancel_hrtimer(event);
9744 task_clock_event_update(event, event->ctx->time);
9747 static int task_clock_event_add(struct perf_event *event, int flags)
9749 if (flags & PERF_EF_START)
9750 task_clock_event_start(event, flags);
9751 perf_event_update_userpage(event);
9756 static void task_clock_event_del(struct perf_event *event, int flags)
9758 task_clock_event_stop(event, PERF_EF_UPDATE);
9761 static void task_clock_event_read(struct perf_event *event)
9763 u64 now = perf_clock();
9764 u64 delta = now - event->ctx->timestamp;
9765 u64 time = event->ctx->time + delta;
9767 task_clock_event_update(event, time);
9770 static int task_clock_event_init(struct perf_event *event)
9772 if (event->attr.type != PERF_TYPE_SOFTWARE)
9775 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9779 * no branch sampling for software events
9781 if (has_branch_stack(event))
9784 perf_swevent_init_hrtimer(event);
9789 static struct pmu perf_task_clock = {
9790 .task_ctx_nr = perf_sw_context,
9792 .capabilities = PERF_PMU_CAP_NO_NMI,
9794 .event_init = task_clock_event_init,
9795 .add = task_clock_event_add,
9796 .del = task_clock_event_del,
9797 .start = task_clock_event_start,
9798 .stop = task_clock_event_stop,
9799 .read = task_clock_event_read,
9802 static void perf_pmu_nop_void(struct pmu *pmu)
9806 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9810 static int perf_pmu_nop_int(struct pmu *pmu)
9815 static int perf_event_nop_int(struct perf_event *event, u64 value)
9820 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9822 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9824 __this_cpu_write(nop_txn_flags, flags);
9826 if (flags & ~PERF_PMU_TXN_ADD)
9829 perf_pmu_disable(pmu);
9832 static int perf_pmu_commit_txn(struct pmu *pmu)
9834 unsigned int flags = __this_cpu_read(nop_txn_flags);
9836 __this_cpu_write(nop_txn_flags, 0);
9838 if (flags & ~PERF_PMU_TXN_ADD)
9841 perf_pmu_enable(pmu);
9845 static void perf_pmu_cancel_txn(struct pmu *pmu)
9847 unsigned int flags = __this_cpu_read(nop_txn_flags);
9849 __this_cpu_write(nop_txn_flags, 0);
9851 if (flags & ~PERF_PMU_TXN_ADD)
9854 perf_pmu_enable(pmu);
9857 static int perf_event_idx_default(struct perf_event *event)
9863 * Ensures all contexts with the same task_ctx_nr have the same
9864 * pmu_cpu_context too.
9866 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9873 list_for_each_entry(pmu, &pmus, entry) {
9874 if (pmu->task_ctx_nr == ctxn)
9875 return pmu->pmu_cpu_context;
9881 static void free_pmu_context(struct pmu *pmu)
9884 * Static contexts such as perf_sw_context have a global lifetime
9885 * and may be shared between different PMUs. Avoid freeing them
9886 * when a single PMU is going away.
9888 if (pmu->task_ctx_nr > perf_invalid_context)
9891 free_percpu(pmu->pmu_cpu_context);
9895 * Let userspace know that this PMU supports address range filtering:
9897 static ssize_t nr_addr_filters_show(struct device *dev,
9898 struct device_attribute *attr,
9901 struct pmu *pmu = dev_get_drvdata(dev);
9903 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9905 DEVICE_ATTR_RO(nr_addr_filters);
9907 static struct idr pmu_idr;
9910 type_show(struct device *dev, struct device_attribute *attr, char *page)
9912 struct pmu *pmu = dev_get_drvdata(dev);
9914 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9916 static DEVICE_ATTR_RO(type);
9919 perf_event_mux_interval_ms_show(struct device *dev,
9920 struct device_attribute *attr,
9923 struct pmu *pmu = dev_get_drvdata(dev);
9925 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9928 static DEFINE_MUTEX(mux_interval_mutex);
9931 perf_event_mux_interval_ms_store(struct device *dev,
9932 struct device_attribute *attr,
9933 const char *buf, size_t count)
9935 struct pmu *pmu = dev_get_drvdata(dev);
9936 int timer, cpu, ret;
9938 ret = kstrtoint(buf, 0, &timer);
9945 /* same value, noting to do */
9946 if (timer == pmu->hrtimer_interval_ms)
9949 mutex_lock(&mux_interval_mutex);
9950 pmu->hrtimer_interval_ms = timer;
9952 /* update all cpuctx for this PMU */
9954 for_each_online_cpu(cpu) {
9955 struct perf_cpu_context *cpuctx;
9956 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9957 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9959 cpu_function_call(cpu,
9960 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9963 mutex_unlock(&mux_interval_mutex);
9967 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9969 static struct attribute *pmu_dev_attrs[] = {
9970 &dev_attr_type.attr,
9971 &dev_attr_perf_event_mux_interval_ms.attr,
9974 ATTRIBUTE_GROUPS(pmu_dev);
9976 static int pmu_bus_running;
9977 static struct bus_type pmu_bus = {
9978 .name = "event_source",
9979 .dev_groups = pmu_dev_groups,
9982 static void pmu_dev_release(struct device *dev)
9987 static int pmu_dev_alloc(struct pmu *pmu)
9991 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9995 pmu->dev->groups = pmu->attr_groups;
9996 device_initialize(pmu->dev);
9997 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10001 dev_set_drvdata(pmu->dev, pmu);
10002 pmu->dev->bus = &pmu_bus;
10003 pmu->dev->release = pmu_dev_release;
10004 ret = device_add(pmu->dev);
10008 /* For PMUs with address filters, throw in an extra attribute: */
10009 if (pmu->nr_addr_filters)
10010 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10015 if (pmu->attr_update)
10016 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10025 device_del(pmu->dev);
10028 put_device(pmu->dev);
10032 static struct lock_class_key cpuctx_mutex;
10033 static struct lock_class_key cpuctx_lock;
10035 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10039 mutex_lock(&pmus_lock);
10041 pmu->pmu_disable_count = alloc_percpu(int);
10042 if (!pmu->pmu_disable_count)
10051 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
10059 if (pmu_bus_running) {
10060 ret = pmu_dev_alloc(pmu);
10066 if (pmu->task_ctx_nr == perf_hw_context) {
10067 static int hw_context_taken = 0;
10070 * Other than systems with heterogeneous CPUs, it never makes
10071 * sense for two PMUs to share perf_hw_context. PMUs which are
10072 * uncore must use perf_invalid_context.
10074 if (WARN_ON_ONCE(hw_context_taken &&
10075 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10076 pmu->task_ctx_nr = perf_invalid_context;
10078 hw_context_taken = 1;
10081 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10082 if (pmu->pmu_cpu_context)
10083 goto got_cpu_context;
10086 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10087 if (!pmu->pmu_cpu_context)
10090 for_each_possible_cpu(cpu) {
10091 struct perf_cpu_context *cpuctx;
10093 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10094 __perf_event_init_context(&cpuctx->ctx);
10095 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10096 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10097 cpuctx->ctx.pmu = pmu;
10098 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10100 __perf_mux_hrtimer_init(cpuctx, cpu);
10104 if (!pmu->start_txn) {
10105 if (pmu->pmu_enable) {
10107 * If we have pmu_enable/pmu_disable calls, install
10108 * transaction stubs that use that to try and batch
10109 * hardware accesses.
10111 pmu->start_txn = perf_pmu_start_txn;
10112 pmu->commit_txn = perf_pmu_commit_txn;
10113 pmu->cancel_txn = perf_pmu_cancel_txn;
10115 pmu->start_txn = perf_pmu_nop_txn;
10116 pmu->commit_txn = perf_pmu_nop_int;
10117 pmu->cancel_txn = perf_pmu_nop_void;
10121 if (!pmu->pmu_enable) {
10122 pmu->pmu_enable = perf_pmu_nop_void;
10123 pmu->pmu_disable = perf_pmu_nop_void;
10126 if (!pmu->check_period)
10127 pmu->check_period = perf_event_nop_int;
10129 if (!pmu->event_idx)
10130 pmu->event_idx = perf_event_idx_default;
10132 list_add_rcu(&pmu->entry, &pmus);
10133 atomic_set(&pmu->exclusive_cnt, 0);
10136 mutex_unlock(&pmus_lock);
10141 device_del(pmu->dev);
10142 put_device(pmu->dev);
10145 if (pmu->type >= PERF_TYPE_MAX)
10146 idr_remove(&pmu_idr, pmu->type);
10149 free_percpu(pmu->pmu_disable_count);
10152 EXPORT_SYMBOL_GPL(perf_pmu_register);
10154 void perf_pmu_unregister(struct pmu *pmu)
10156 mutex_lock(&pmus_lock);
10157 list_del_rcu(&pmu->entry);
10160 * We dereference the pmu list under both SRCU and regular RCU, so
10161 * synchronize against both of those.
10163 synchronize_srcu(&pmus_srcu);
10166 free_percpu(pmu->pmu_disable_count);
10167 if (pmu->type >= PERF_TYPE_MAX)
10168 idr_remove(&pmu_idr, pmu->type);
10169 if (pmu_bus_running) {
10170 if (pmu->nr_addr_filters)
10171 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10172 device_del(pmu->dev);
10173 put_device(pmu->dev);
10175 free_pmu_context(pmu);
10176 mutex_unlock(&pmus_lock);
10178 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10180 static inline bool has_extended_regs(struct perf_event *event)
10182 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10183 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10186 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10188 struct perf_event_context *ctx = NULL;
10191 if (!try_module_get(pmu->module))
10195 * A number of pmu->event_init() methods iterate the sibling_list to,
10196 * for example, validate if the group fits on the PMU. Therefore,
10197 * if this is a sibling event, acquire the ctx->mutex to protect
10198 * the sibling_list.
10200 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10202 * This ctx->mutex can nest when we're called through
10203 * inheritance. See the perf_event_ctx_lock_nested() comment.
10205 ctx = perf_event_ctx_lock_nested(event->group_leader,
10206 SINGLE_DEPTH_NESTING);
10211 ret = pmu->event_init(event);
10214 perf_event_ctx_unlock(event->group_leader, ctx);
10217 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10218 has_extended_regs(event))
10221 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10222 event_has_any_exclude_flag(event))
10225 if (ret && event->destroy)
10226 event->destroy(event);
10230 module_put(pmu->module);
10235 static struct pmu *perf_init_event(struct perf_event *event)
10241 idx = srcu_read_lock(&pmus_srcu);
10243 /* Try parent's PMU first: */
10244 if (event->parent && event->parent->pmu) {
10245 pmu = event->parent->pmu;
10246 ret = perf_try_init_event(pmu, event);
10252 pmu = idr_find(&pmu_idr, event->attr.type);
10255 ret = perf_try_init_event(pmu, event);
10257 pmu = ERR_PTR(ret);
10261 list_for_each_entry_rcu(pmu, &pmus, entry) {
10262 ret = perf_try_init_event(pmu, event);
10266 if (ret != -ENOENT) {
10267 pmu = ERR_PTR(ret);
10271 pmu = ERR_PTR(-ENOENT);
10273 srcu_read_unlock(&pmus_srcu, idx);
10278 static void attach_sb_event(struct perf_event *event)
10280 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10282 raw_spin_lock(&pel->lock);
10283 list_add_rcu(&event->sb_list, &pel->list);
10284 raw_spin_unlock(&pel->lock);
10288 * We keep a list of all !task (and therefore per-cpu) events
10289 * that need to receive side-band records.
10291 * This avoids having to scan all the various PMU per-cpu contexts
10292 * looking for them.
10294 static void account_pmu_sb_event(struct perf_event *event)
10296 if (is_sb_event(event))
10297 attach_sb_event(event);
10300 static void account_event_cpu(struct perf_event *event, int cpu)
10305 if (is_cgroup_event(event))
10306 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10309 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10310 static void account_freq_event_nohz(void)
10312 #ifdef CONFIG_NO_HZ_FULL
10313 /* Lock so we don't race with concurrent unaccount */
10314 spin_lock(&nr_freq_lock);
10315 if (atomic_inc_return(&nr_freq_events) == 1)
10316 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10317 spin_unlock(&nr_freq_lock);
10321 static void account_freq_event(void)
10323 if (tick_nohz_full_enabled())
10324 account_freq_event_nohz();
10326 atomic_inc(&nr_freq_events);
10330 static void account_event(struct perf_event *event)
10337 if (event->attach_state & PERF_ATTACH_TASK)
10339 if (event->attr.mmap || event->attr.mmap_data)
10340 atomic_inc(&nr_mmap_events);
10341 if (event->attr.comm)
10342 atomic_inc(&nr_comm_events);
10343 if (event->attr.namespaces)
10344 atomic_inc(&nr_namespaces_events);
10345 if (event->attr.task)
10346 atomic_inc(&nr_task_events);
10347 if (event->attr.freq)
10348 account_freq_event();
10349 if (event->attr.context_switch) {
10350 atomic_inc(&nr_switch_events);
10353 if (has_branch_stack(event))
10355 if (is_cgroup_event(event))
10357 if (event->attr.ksymbol)
10358 atomic_inc(&nr_ksymbol_events);
10359 if (event->attr.bpf_event)
10360 atomic_inc(&nr_bpf_events);
10364 * We need the mutex here because static_branch_enable()
10365 * must complete *before* the perf_sched_count increment
10368 if (atomic_inc_not_zero(&perf_sched_count))
10371 mutex_lock(&perf_sched_mutex);
10372 if (!atomic_read(&perf_sched_count)) {
10373 static_branch_enable(&perf_sched_events);
10375 * Guarantee that all CPUs observe they key change and
10376 * call the perf scheduling hooks before proceeding to
10377 * install events that need them.
10382 * Now that we have waited for the sync_sched(), allow further
10383 * increments to by-pass the mutex.
10385 atomic_inc(&perf_sched_count);
10386 mutex_unlock(&perf_sched_mutex);
10390 account_event_cpu(event, event->cpu);
10392 account_pmu_sb_event(event);
10396 * Allocate and initialize an event structure
10398 static struct perf_event *
10399 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10400 struct task_struct *task,
10401 struct perf_event *group_leader,
10402 struct perf_event *parent_event,
10403 perf_overflow_handler_t overflow_handler,
10404 void *context, int cgroup_fd)
10407 struct perf_event *event;
10408 struct hw_perf_event *hwc;
10409 long err = -EINVAL;
10411 if ((unsigned)cpu >= nr_cpu_ids) {
10412 if (!task || cpu != -1)
10413 return ERR_PTR(-EINVAL);
10416 event = kzalloc(sizeof(*event), GFP_KERNEL);
10418 return ERR_PTR(-ENOMEM);
10421 * Single events are their own group leaders, with an
10422 * empty sibling list:
10425 group_leader = event;
10427 mutex_init(&event->child_mutex);
10428 INIT_LIST_HEAD(&event->child_list);
10430 INIT_LIST_HEAD(&event->event_entry);
10431 INIT_LIST_HEAD(&event->sibling_list);
10432 INIT_LIST_HEAD(&event->active_list);
10433 init_event_group(event);
10434 INIT_LIST_HEAD(&event->rb_entry);
10435 INIT_LIST_HEAD(&event->active_entry);
10436 INIT_LIST_HEAD(&event->addr_filters.list);
10437 INIT_HLIST_NODE(&event->hlist_entry);
10440 init_waitqueue_head(&event->waitq);
10441 event->pending_disable = -1;
10442 init_irq_work(&event->pending, perf_pending_event);
10444 mutex_init(&event->mmap_mutex);
10445 raw_spin_lock_init(&event->addr_filters.lock);
10447 atomic_long_set(&event->refcount, 1);
10449 event->attr = *attr;
10450 event->group_leader = group_leader;
10454 event->parent = parent_event;
10456 event->ns = get_pid_ns(task_active_pid_ns(current));
10457 event->id = atomic64_inc_return(&perf_event_id);
10459 event->state = PERF_EVENT_STATE_INACTIVE;
10462 event->attach_state = PERF_ATTACH_TASK;
10464 * XXX pmu::event_init needs to know what task to account to
10465 * and we cannot use the ctx information because we need the
10466 * pmu before we get a ctx.
10468 event->hw.target = get_task_struct(task);
10471 event->clock = &local_clock;
10473 event->clock = parent_event->clock;
10475 if (!overflow_handler && parent_event) {
10476 overflow_handler = parent_event->overflow_handler;
10477 context = parent_event->overflow_handler_context;
10478 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10479 if (overflow_handler == bpf_overflow_handler) {
10480 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10482 if (IS_ERR(prog)) {
10483 err = PTR_ERR(prog);
10486 event->prog = prog;
10487 event->orig_overflow_handler =
10488 parent_event->orig_overflow_handler;
10493 if (overflow_handler) {
10494 event->overflow_handler = overflow_handler;
10495 event->overflow_handler_context = context;
10496 } else if (is_write_backward(event)){
10497 event->overflow_handler = perf_event_output_backward;
10498 event->overflow_handler_context = NULL;
10500 event->overflow_handler = perf_event_output_forward;
10501 event->overflow_handler_context = NULL;
10504 perf_event__state_init(event);
10509 hwc->sample_period = attr->sample_period;
10510 if (attr->freq && attr->sample_freq)
10511 hwc->sample_period = 1;
10512 hwc->last_period = hwc->sample_period;
10514 local64_set(&hwc->period_left, hwc->sample_period);
10517 * We currently do not support PERF_SAMPLE_READ on inherited events.
10518 * See perf_output_read().
10520 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10523 if (!has_branch_stack(event))
10524 event->attr.branch_sample_type = 0;
10526 if (cgroup_fd != -1) {
10527 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10532 pmu = perf_init_event(event);
10534 err = PTR_ERR(pmu);
10538 if (event->attr.aux_output &&
10539 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10544 err = exclusive_event_init(event);
10548 if (has_addr_filter(event)) {
10549 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10550 sizeof(struct perf_addr_filter_range),
10552 if (!event->addr_filter_ranges) {
10558 * Clone the parent's vma offsets: they are valid until exec()
10559 * even if the mm is not shared with the parent.
10561 if (event->parent) {
10562 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10564 raw_spin_lock_irq(&ifh->lock);
10565 memcpy(event->addr_filter_ranges,
10566 event->parent->addr_filter_ranges,
10567 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10568 raw_spin_unlock_irq(&ifh->lock);
10571 /* force hw sync on the address filters */
10572 event->addr_filters_gen = 1;
10575 if (!event->parent) {
10576 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10577 err = get_callchain_buffers(attr->sample_max_stack);
10579 goto err_addr_filters;
10583 /* symmetric to unaccount_event() in _free_event() */
10584 account_event(event);
10589 kfree(event->addr_filter_ranges);
10592 exclusive_event_destroy(event);
10595 if (event->destroy)
10596 event->destroy(event);
10597 module_put(pmu->module);
10599 if (is_cgroup_event(event))
10600 perf_detach_cgroup(event);
10602 put_pid_ns(event->ns);
10603 if (event->hw.target)
10604 put_task_struct(event->hw.target);
10607 return ERR_PTR(err);
10610 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10611 struct perf_event_attr *attr)
10616 /* Zero the full structure, so that a short copy will be nice. */
10617 memset(attr, 0, sizeof(*attr));
10619 ret = get_user(size, &uattr->size);
10623 /* ABI compatibility quirk: */
10625 size = PERF_ATTR_SIZE_VER0;
10626 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
10629 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
10638 if (attr->__reserved_1 || attr->__reserved_2)
10641 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10644 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10647 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10648 u64 mask = attr->branch_sample_type;
10650 /* only using defined bits */
10651 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10654 /* at least one branch bit must be set */
10655 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10658 /* propagate priv level, when not set for branch */
10659 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10661 /* exclude_kernel checked on syscall entry */
10662 if (!attr->exclude_kernel)
10663 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10665 if (!attr->exclude_user)
10666 mask |= PERF_SAMPLE_BRANCH_USER;
10668 if (!attr->exclude_hv)
10669 mask |= PERF_SAMPLE_BRANCH_HV;
10671 * adjust user setting (for HW filter setup)
10673 attr->branch_sample_type = mask;
10675 /* privileged levels capture (kernel, hv): check permissions */
10676 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10677 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10681 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10682 ret = perf_reg_validate(attr->sample_regs_user);
10687 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10688 if (!arch_perf_have_user_stack_dump())
10692 * We have __u32 type for the size, but so far
10693 * we can only use __u16 as maximum due to the
10694 * __u16 sample size limit.
10696 if (attr->sample_stack_user >= USHRT_MAX)
10698 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10702 if (!attr->sample_max_stack)
10703 attr->sample_max_stack = sysctl_perf_event_max_stack;
10705 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10706 ret = perf_reg_validate(attr->sample_regs_intr);
10711 put_user(sizeof(*attr), &uattr->size);
10717 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10719 struct ring_buffer *rb = NULL;
10725 /* don't allow circular references */
10726 if (event == output_event)
10730 * Don't allow cross-cpu buffers
10732 if (output_event->cpu != event->cpu)
10736 * If its not a per-cpu rb, it must be the same task.
10738 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10742 * Mixing clocks in the same buffer is trouble you don't need.
10744 if (output_event->clock != event->clock)
10748 * Either writing ring buffer from beginning or from end.
10749 * Mixing is not allowed.
10751 if (is_write_backward(output_event) != is_write_backward(event))
10755 * If both events generate aux data, they must be on the same PMU
10757 if (has_aux(event) && has_aux(output_event) &&
10758 event->pmu != output_event->pmu)
10762 mutex_lock(&event->mmap_mutex);
10763 /* Can't redirect output if we've got an active mmap() */
10764 if (atomic_read(&event->mmap_count))
10767 if (output_event) {
10768 /* get the rb we want to redirect to */
10769 rb = ring_buffer_get(output_event);
10774 ring_buffer_attach(event, rb);
10778 mutex_unlock(&event->mmap_mutex);
10784 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10790 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10793 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10795 bool nmi_safe = false;
10798 case CLOCK_MONOTONIC:
10799 event->clock = &ktime_get_mono_fast_ns;
10803 case CLOCK_MONOTONIC_RAW:
10804 event->clock = &ktime_get_raw_fast_ns;
10808 case CLOCK_REALTIME:
10809 event->clock = &ktime_get_real_ns;
10812 case CLOCK_BOOTTIME:
10813 event->clock = &ktime_get_boottime_ns;
10817 event->clock = &ktime_get_clocktai_ns;
10824 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10831 * Variation on perf_event_ctx_lock_nested(), except we take two context
10834 static struct perf_event_context *
10835 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10836 struct perf_event_context *ctx)
10838 struct perf_event_context *gctx;
10842 gctx = READ_ONCE(group_leader->ctx);
10843 if (!refcount_inc_not_zero(&gctx->refcount)) {
10849 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10851 if (group_leader->ctx != gctx) {
10852 mutex_unlock(&ctx->mutex);
10853 mutex_unlock(&gctx->mutex);
10862 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10864 * @attr_uptr: event_id type attributes for monitoring/sampling
10867 * @group_fd: group leader event fd
10869 SYSCALL_DEFINE5(perf_event_open,
10870 struct perf_event_attr __user *, attr_uptr,
10871 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10873 struct perf_event *group_leader = NULL, *output_event = NULL;
10874 struct perf_event *event, *sibling;
10875 struct perf_event_attr attr;
10876 struct perf_event_context *ctx, *uninitialized_var(gctx);
10877 struct file *event_file = NULL;
10878 struct fd group = {NULL, 0};
10879 struct task_struct *task = NULL;
10882 int move_group = 0;
10884 int f_flags = O_RDWR;
10885 int cgroup_fd = -1;
10887 /* for future expandability... */
10888 if (flags & ~PERF_FLAG_ALL)
10891 err = perf_copy_attr(attr_uptr, &attr);
10895 if (!attr.exclude_kernel) {
10896 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10900 if (attr.namespaces) {
10901 if (!capable(CAP_SYS_ADMIN))
10906 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10909 if (attr.sample_period & (1ULL << 63))
10913 /* Only privileged users can get physical addresses */
10914 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10915 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10918 err = security_locked_down(LOCKDOWN_PERF);
10919 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
10920 /* REGS_INTR can leak data, lockdown must prevent this */
10926 * In cgroup mode, the pid argument is used to pass the fd
10927 * opened to the cgroup directory in cgroupfs. The cpu argument
10928 * designates the cpu on which to monitor threads from that
10931 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10934 if (flags & PERF_FLAG_FD_CLOEXEC)
10935 f_flags |= O_CLOEXEC;
10937 event_fd = get_unused_fd_flags(f_flags);
10941 if (group_fd != -1) {
10942 err = perf_fget_light(group_fd, &group);
10945 group_leader = group.file->private_data;
10946 if (flags & PERF_FLAG_FD_OUTPUT)
10947 output_event = group_leader;
10948 if (flags & PERF_FLAG_FD_NO_GROUP)
10949 group_leader = NULL;
10952 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10953 task = find_lively_task_by_vpid(pid);
10954 if (IS_ERR(task)) {
10955 err = PTR_ERR(task);
10960 if (task && group_leader &&
10961 group_leader->attr.inherit != attr.inherit) {
10967 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10972 * Reuse ptrace permission checks for now.
10974 * We must hold cred_guard_mutex across this and any potential
10975 * perf_install_in_context() call for this new event to
10976 * serialize against exec() altering our credentials (and the
10977 * perf_event_exit_task() that could imply).
10980 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10984 if (flags & PERF_FLAG_PID_CGROUP)
10987 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10988 NULL, NULL, cgroup_fd);
10989 if (IS_ERR(event)) {
10990 err = PTR_ERR(event);
10994 if (is_sampling_event(event)) {
10995 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11002 * Special case software events and allow them to be part of
11003 * any hardware group.
11007 if (attr.use_clockid) {
11008 err = perf_event_set_clock(event, attr.clockid);
11013 if (pmu->task_ctx_nr == perf_sw_context)
11014 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11016 if (group_leader) {
11017 if (is_software_event(event) &&
11018 !in_software_context(group_leader)) {
11020 * If the event is a sw event, but the group_leader
11021 * is on hw context.
11023 * Allow the addition of software events to hw
11024 * groups, this is safe because software events
11025 * never fail to schedule.
11027 pmu = group_leader->ctx->pmu;
11028 } else if (!is_software_event(event) &&
11029 is_software_event(group_leader) &&
11030 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11032 * In case the group is a pure software group, and we
11033 * try to add a hardware event, move the whole group to
11034 * the hardware context.
11041 * Get the target context (task or percpu):
11043 ctx = find_get_context(pmu, task, event);
11045 err = PTR_ERR(ctx);
11050 * Look up the group leader (we will attach this event to it):
11052 if (group_leader) {
11056 * Do not allow a recursive hierarchy (this new sibling
11057 * becoming part of another group-sibling):
11059 if (group_leader->group_leader != group_leader)
11062 /* All events in a group should have the same clock */
11063 if (group_leader->clock != event->clock)
11067 * Make sure we're both events for the same CPU;
11068 * grouping events for different CPUs is broken; since
11069 * you can never concurrently schedule them anyhow.
11071 if (group_leader->cpu != event->cpu)
11075 * Make sure we're both on the same task, or both
11078 if (group_leader->ctx->task != ctx->task)
11082 * Do not allow to attach to a group in a different task
11083 * or CPU context. If we're moving SW events, we'll fix
11084 * this up later, so allow that.
11086 if (!move_group && group_leader->ctx != ctx)
11090 * Only a group leader can be exclusive or pinned
11092 if (attr.exclusive || attr.pinned)
11096 if (output_event) {
11097 err = perf_event_set_output(event, output_event);
11102 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11104 if (IS_ERR(event_file)) {
11105 err = PTR_ERR(event_file);
11111 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11113 if (gctx->task == TASK_TOMBSTONE) {
11119 * Check if we raced against another sys_perf_event_open() call
11120 * moving the software group underneath us.
11122 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11124 * If someone moved the group out from under us, check
11125 * if this new event wound up on the same ctx, if so
11126 * its the regular !move_group case, otherwise fail.
11132 perf_event_ctx_unlock(group_leader, gctx);
11138 * Failure to create exclusive events returns -EBUSY.
11141 if (!exclusive_event_installable(group_leader, ctx))
11144 for_each_sibling_event(sibling, group_leader) {
11145 if (!exclusive_event_installable(sibling, ctx))
11149 mutex_lock(&ctx->mutex);
11152 if (ctx->task == TASK_TOMBSTONE) {
11157 if (!perf_event_validate_size(event)) {
11164 * Check if the @cpu we're creating an event for is online.
11166 * We use the perf_cpu_context::ctx::mutex to serialize against
11167 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11169 struct perf_cpu_context *cpuctx =
11170 container_of(ctx, struct perf_cpu_context, ctx);
11172 if (!cpuctx->online) {
11178 if (event->attr.aux_output && !perf_get_aux_event(event, group_leader))
11182 * Must be under the same ctx::mutex as perf_install_in_context(),
11183 * because we need to serialize with concurrent event creation.
11185 if (!exclusive_event_installable(event, ctx)) {
11190 WARN_ON_ONCE(ctx->parent_ctx);
11193 * This is the point on no return; we cannot fail hereafter. This is
11194 * where we start modifying current state.
11199 * See perf_event_ctx_lock() for comments on the details
11200 * of swizzling perf_event::ctx.
11202 perf_remove_from_context(group_leader, 0);
11205 for_each_sibling_event(sibling, group_leader) {
11206 perf_remove_from_context(sibling, 0);
11211 * Wait for everybody to stop referencing the events through
11212 * the old lists, before installing it on new lists.
11217 * Install the group siblings before the group leader.
11219 * Because a group leader will try and install the entire group
11220 * (through the sibling list, which is still in-tact), we can
11221 * end up with siblings installed in the wrong context.
11223 * By installing siblings first we NO-OP because they're not
11224 * reachable through the group lists.
11226 for_each_sibling_event(sibling, group_leader) {
11227 perf_event__state_init(sibling);
11228 perf_install_in_context(ctx, sibling, sibling->cpu);
11233 * Removing from the context ends up with disabled
11234 * event. What we want here is event in the initial
11235 * startup state, ready to be add into new context.
11237 perf_event__state_init(group_leader);
11238 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11243 * Precalculate sample_data sizes; do while holding ctx::mutex such
11244 * that we're serialized against further additions and before
11245 * perf_install_in_context() which is the point the event is active and
11246 * can use these values.
11248 perf_event__header_size(event);
11249 perf_event__id_header_size(event);
11251 event->owner = current;
11253 perf_install_in_context(ctx, event, event->cpu);
11254 perf_unpin_context(ctx);
11257 perf_event_ctx_unlock(group_leader, gctx);
11258 mutex_unlock(&ctx->mutex);
11261 mutex_unlock(&task->signal->cred_guard_mutex);
11262 put_task_struct(task);
11265 mutex_lock(¤t->perf_event_mutex);
11266 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11267 mutex_unlock(¤t->perf_event_mutex);
11270 * Drop the reference on the group_event after placing the
11271 * new event on the sibling_list. This ensures destruction
11272 * of the group leader will find the pointer to itself in
11273 * perf_group_detach().
11276 fd_install(event_fd, event_file);
11281 perf_event_ctx_unlock(group_leader, gctx);
11282 mutex_unlock(&ctx->mutex);
11286 perf_unpin_context(ctx);
11290 * If event_file is set, the fput() above will have called ->release()
11291 * and that will take care of freeing the event.
11297 mutex_unlock(&task->signal->cred_guard_mutex);
11300 put_task_struct(task);
11304 put_unused_fd(event_fd);
11309 * perf_event_create_kernel_counter
11311 * @attr: attributes of the counter to create
11312 * @cpu: cpu in which the counter is bound
11313 * @task: task to profile (NULL for percpu)
11315 struct perf_event *
11316 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11317 struct task_struct *task,
11318 perf_overflow_handler_t overflow_handler,
11321 struct perf_event_context *ctx;
11322 struct perf_event *event;
11326 * Get the target context (task or percpu):
11329 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11330 overflow_handler, context, -1);
11331 if (IS_ERR(event)) {
11332 err = PTR_ERR(event);
11336 /* Mark owner so we could distinguish it from user events. */
11337 event->owner = TASK_TOMBSTONE;
11339 ctx = find_get_context(event->pmu, task, event);
11341 err = PTR_ERR(ctx);
11345 WARN_ON_ONCE(ctx->parent_ctx);
11346 mutex_lock(&ctx->mutex);
11347 if (ctx->task == TASK_TOMBSTONE) {
11354 * Check if the @cpu we're creating an event for is online.
11356 * We use the perf_cpu_context::ctx::mutex to serialize against
11357 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11359 struct perf_cpu_context *cpuctx =
11360 container_of(ctx, struct perf_cpu_context, ctx);
11361 if (!cpuctx->online) {
11367 if (!exclusive_event_installable(event, ctx)) {
11372 perf_install_in_context(ctx, event, event->cpu);
11373 perf_unpin_context(ctx);
11374 mutex_unlock(&ctx->mutex);
11379 mutex_unlock(&ctx->mutex);
11380 perf_unpin_context(ctx);
11385 return ERR_PTR(err);
11387 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11389 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11391 struct perf_event_context *src_ctx;
11392 struct perf_event_context *dst_ctx;
11393 struct perf_event *event, *tmp;
11396 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11397 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11400 * See perf_event_ctx_lock() for comments on the details
11401 * of swizzling perf_event::ctx.
11403 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11404 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11406 perf_remove_from_context(event, 0);
11407 unaccount_event_cpu(event, src_cpu);
11409 list_add(&event->migrate_entry, &events);
11413 * Wait for the events to quiesce before re-instating them.
11418 * Re-instate events in 2 passes.
11420 * Skip over group leaders and only install siblings on this first
11421 * pass, siblings will not get enabled without a leader, however a
11422 * leader will enable its siblings, even if those are still on the old
11425 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11426 if (event->group_leader == event)
11429 list_del(&event->migrate_entry);
11430 if (event->state >= PERF_EVENT_STATE_OFF)
11431 event->state = PERF_EVENT_STATE_INACTIVE;
11432 account_event_cpu(event, dst_cpu);
11433 perf_install_in_context(dst_ctx, event, dst_cpu);
11438 * Once all the siblings are setup properly, install the group leaders
11441 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11442 list_del(&event->migrate_entry);
11443 if (event->state >= PERF_EVENT_STATE_OFF)
11444 event->state = PERF_EVENT_STATE_INACTIVE;
11445 account_event_cpu(event, dst_cpu);
11446 perf_install_in_context(dst_ctx, event, dst_cpu);
11449 mutex_unlock(&dst_ctx->mutex);
11450 mutex_unlock(&src_ctx->mutex);
11452 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11454 static void sync_child_event(struct perf_event *child_event,
11455 struct task_struct *child)
11457 struct perf_event *parent_event = child_event->parent;
11460 if (child_event->attr.inherit_stat)
11461 perf_event_read_event(child_event, child);
11463 child_val = perf_event_count(child_event);
11466 * Add back the child's count to the parent's count:
11468 atomic64_add(child_val, &parent_event->child_count);
11469 atomic64_add(child_event->total_time_enabled,
11470 &parent_event->child_total_time_enabled);
11471 atomic64_add(child_event->total_time_running,
11472 &parent_event->child_total_time_running);
11476 perf_event_exit_event(struct perf_event *child_event,
11477 struct perf_event_context *child_ctx,
11478 struct task_struct *child)
11480 struct perf_event *parent_event = child_event->parent;
11483 * Do not destroy the 'original' grouping; because of the context
11484 * switch optimization the original events could've ended up in a
11485 * random child task.
11487 * If we were to destroy the original group, all group related
11488 * operations would cease to function properly after this random
11491 * Do destroy all inherited groups, we don't care about those
11492 * and being thorough is better.
11494 raw_spin_lock_irq(&child_ctx->lock);
11495 WARN_ON_ONCE(child_ctx->is_active);
11498 perf_group_detach(child_event);
11499 list_del_event(child_event, child_ctx);
11500 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11501 raw_spin_unlock_irq(&child_ctx->lock);
11504 * Parent events are governed by their filedesc, retain them.
11506 if (!parent_event) {
11507 perf_event_wakeup(child_event);
11511 * Child events can be cleaned up.
11514 sync_child_event(child_event, child);
11517 * Remove this event from the parent's list
11519 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11520 mutex_lock(&parent_event->child_mutex);
11521 list_del_init(&child_event->child_list);
11522 mutex_unlock(&parent_event->child_mutex);
11525 * Kick perf_poll() for is_event_hup().
11527 perf_event_wakeup(parent_event);
11528 free_event(child_event);
11529 put_event(parent_event);
11532 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11534 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11535 struct perf_event *child_event, *next;
11537 WARN_ON_ONCE(child != current);
11539 child_ctx = perf_pin_task_context(child, ctxn);
11544 * In order to reduce the amount of tricky in ctx tear-down, we hold
11545 * ctx::mutex over the entire thing. This serializes against almost
11546 * everything that wants to access the ctx.
11548 * The exception is sys_perf_event_open() /
11549 * perf_event_create_kernel_count() which does find_get_context()
11550 * without ctx::mutex (it cannot because of the move_group double mutex
11551 * lock thing). See the comments in perf_install_in_context().
11553 mutex_lock(&child_ctx->mutex);
11556 * In a single ctx::lock section, de-schedule the events and detach the
11557 * context from the task such that we cannot ever get it scheduled back
11560 raw_spin_lock_irq(&child_ctx->lock);
11561 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11564 * Now that the context is inactive, destroy the task <-> ctx relation
11565 * and mark the context dead.
11567 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11568 put_ctx(child_ctx); /* cannot be last */
11569 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11570 put_task_struct(current); /* cannot be last */
11572 clone_ctx = unclone_ctx(child_ctx);
11573 raw_spin_unlock_irq(&child_ctx->lock);
11576 put_ctx(clone_ctx);
11579 * Report the task dead after unscheduling the events so that we
11580 * won't get any samples after PERF_RECORD_EXIT. We can however still
11581 * get a few PERF_RECORD_READ events.
11583 perf_event_task(child, child_ctx, 0);
11585 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11586 perf_event_exit_event(child_event, child_ctx, child);
11588 mutex_unlock(&child_ctx->mutex);
11590 put_ctx(child_ctx);
11594 * When a child task exits, feed back event values to parent events.
11596 * Can be called with cred_guard_mutex held when called from
11597 * install_exec_creds().
11599 void perf_event_exit_task(struct task_struct *child)
11601 struct perf_event *event, *tmp;
11604 mutex_lock(&child->perf_event_mutex);
11605 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11607 list_del_init(&event->owner_entry);
11610 * Ensure the list deletion is visible before we clear
11611 * the owner, closes a race against perf_release() where
11612 * we need to serialize on the owner->perf_event_mutex.
11614 smp_store_release(&event->owner, NULL);
11616 mutex_unlock(&child->perf_event_mutex);
11618 for_each_task_context_nr(ctxn)
11619 perf_event_exit_task_context(child, ctxn);
11622 * The perf_event_exit_task_context calls perf_event_task
11623 * with child's task_ctx, which generates EXIT events for
11624 * child contexts and sets child->perf_event_ctxp[] to NULL.
11625 * At this point we need to send EXIT events to cpu contexts.
11627 perf_event_task(child, NULL, 0);
11630 static void perf_free_event(struct perf_event *event,
11631 struct perf_event_context *ctx)
11633 struct perf_event *parent = event->parent;
11635 if (WARN_ON_ONCE(!parent))
11638 mutex_lock(&parent->child_mutex);
11639 list_del_init(&event->child_list);
11640 mutex_unlock(&parent->child_mutex);
11644 raw_spin_lock_irq(&ctx->lock);
11645 perf_group_detach(event);
11646 list_del_event(event, ctx);
11647 raw_spin_unlock_irq(&ctx->lock);
11652 * Free a context as created by inheritance by perf_event_init_task() below,
11653 * used by fork() in case of fail.
11655 * Even though the task has never lived, the context and events have been
11656 * exposed through the child_list, so we must take care tearing it all down.
11658 void perf_event_free_task(struct task_struct *task)
11660 struct perf_event_context *ctx;
11661 struct perf_event *event, *tmp;
11664 for_each_task_context_nr(ctxn) {
11665 ctx = task->perf_event_ctxp[ctxn];
11669 mutex_lock(&ctx->mutex);
11670 raw_spin_lock_irq(&ctx->lock);
11672 * Destroy the task <-> ctx relation and mark the context dead.
11674 * This is important because even though the task hasn't been
11675 * exposed yet the context has been (through child_list).
11677 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11678 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11679 put_task_struct(task); /* cannot be last */
11680 raw_spin_unlock_irq(&ctx->lock);
11682 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11683 perf_free_event(event, ctx);
11685 mutex_unlock(&ctx->mutex);
11688 * perf_event_release_kernel() could've stolen some of our
11689 * child events and still have them on its free_list. In that
11690 * case we must wait for these events to have been freed (in
11691 * particular all their references to this task must've been
11694 * Without this copy_process() will unconditionally free this
11695 * task (irrespective of its reference count) and
11696 * _free_event()'s put_task_struct(event->hw.target) will be a
11699 * Wait for all events to drop their context reference.
11701 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
11702 put_ctx(ctx); /* must be last */
11706 void perf_event_delayed_put(struct task_struct *task)
11710 for_each_task_context_nr(ctxn)
11711 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11714 struct file *perf_event_get(unsigned int fd)
11716 struct file *file = fget(fd);
11718 return ERR_PTR(-EBADF);
11720 if (file->f_op != &perf_fops) {
11722 return ERR_PTR(-EBADF);
11728 const struct perf_event *perf_get_event(struct file *file)
11730 if (file->f_op != &perf_fops)
11731 return ERR_PTR(-EINVAL);
11733 return file->private_data;
11736 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11739 return ERR_PTR(-EINVAL);
11741 return &event->attr;
11745 * Inherit an event from parent task to child task.
11748 * - valid pointer on success
11749 * - NULL for orphaned events
11750 * - IS_ERR() on error
11752 static struct perf_event *
11753 inherit_event(struct perf_event *parent_event,
11754 struct task_struct *parent,
11755 struct perf_event_context *parent_ctx,
11756 struct task_struct *child,
11757 struct perf_event *group_leader,
11758 struct perf_event_context *child_ctx)
11760 enum perf_event_state parent_state = parent_event->state;
11761 struct perf_event *child_event;
11762 unsigned long flags;
11765 * Instead of creating recursive hierarchies of events,
11766 * we link inherited events back to the original parent,
11767 * which has a filp for sure, which we use as the reference
11770 if (parent_event->parent)
11771 parent_event = parent_event->parent;
11773 child_event = perf_event_alloc(&parent_event->attr,
11776 group_leader, parent_event,
11778 if (IS_ERR(child_event))
11779 return child_event;
11782 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11783 !child_ctx->task_ctx_data) {
11784 struct pmu *pmu = child_event->pmu;
11786 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11788 if (!child_ctx->task_ctx_data) {
11789 free_event(child_event);
11795 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11796 * must be under the same lock in order to serialize against
11797 * perf_event_release_kernel(), such that either we must observe
11798 * is_orphaned_event() or they will observe us on the child_list.
11800 mutex_lock(&parent_event->child_mutex);
11801 if (is_orphaned_event(parent_event) ||
11802 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11803 mutex_unlock(&parent_event->child_mutex);
11804 /* task_ctx_data is freed with child_ctx */
11805 free_event(child_event);
11809 get_ctx(child_ctx);
11812 * Make the child state follow the state of the parent event,
11813 * not its attr.disabled bit. We hold the parent's mutex,
11814 * so we won't race with perf_event_{en, dis}able_family.
11816 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11817 child_event->state = PERF_EVENT_STATE_INACTIVE;
11819 child_event->state = PERF_EVENT_STATE_OFF;
11821 if (parent_event->attr.freq) {
11822 u64 sample_period = parent_event->hw.sample_period;
11823 struct hw_perf_event *hwc = &child_event->hw;
11825 hwc->sample_period = sample_period;
11826 hwc->last_period = sample_period;
11828 local64_set(&hwc->period_left, sample_period);
11831 child_event->ctx = child_ctx;
11832 child_event->overflow_handler = parent_event->overflow_handler;
11833 child_event->overflow_handler_context
11834 = parent_event->overflow_handler_context;
11837 * Precalculate sample_data sizes
11839 perf_event__header_size(child_event);
11840 perf_event__id_header_size(child_event);
11843 * Link it up in the child's context:
11845 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11846 add_event_to_ctx(child_event, child_ctx);
11847 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11850 * Link this into the parent event's child list
11852 list_add_tail(&child_event->child_list, &parent_event->child_list);
11853 mutex_unlock(&parent_event->child_mutex);
11855 return child_event;
11859 * Inherits an event group.
11861 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11862 * This matches with perf_event_release_kernel() removing all child events.
11868 static int inherit_group(struct perf_event *parent_event,
11869 struct task_struct *parent,
11870 struct perf_event_context *parent_ctx,
11871 struct task_struct *child,
11872 struct perf_event_context *child_ctx)
11874 struct perf_event *leader;
11875 struct perf_event *sub;
11876 struct perf_event *child_ctr;
11878 leader = inherit_event(parent_event, parent, parent_ctx,
11879 child, NULL, child_ctx);
11880 if (IS_ERR(leader))
11881 return PTR_ERR(leader);
11883 * @leader can be NULL here because of is_orphaned_event(). In this
11884 * case inherit_event() will create individual events, similar to what
11885 * perf_group_detach() would do anyway.
11887 for_each_sibling_event(sub, parent_event) {
11888 child_ctr = inherit_event(sub, parent, parent_ctx,
11889 child, leader, child_ctx);
11890 if (IS_ERR(child_ctr))
11891 return PTR_ERR(child_ctr);
11893 if (sub->aux_event == parent_event &&
11894 !perf_get_aux_event(child_ctr, leader))
11901 * Creates the child task context and tries to inherit the event-group.
11903 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11904 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11905 * consistent with perf_event_release_kernel() removing all child events.
11912 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11913 struct perf_event_context *parent_ctx,
11914 struct task_struct *child, int ctxn,
11915 int *inherited_all)
11918 struct perf_event_context *child_ctx;
11920 if (!event->attr.inherit) {
11921 *inherited_all = 0;
11925 child_ctx = child->perf_event_ctxp[ctxn];
11928 * This is executed from the parent task context, so
11929 * inherit events that have been marked for cloning.
11930 * First allocate and initialize a context for the
11933 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11937 child->perf_event_ctxp[ctxn] = child_ctx;
11940 ret = inherit_group(event, parent, parent_ctx,
11944 *inherited_all = 0;
11950 * Initialize the perf_event context in task_struct
11952 static int perf_event_init_context(struct task_struct *child, int ctxn)
11954 struct perf_event_context *child_ctx, *parent_ctx;
11955 struct perf_event_context *cloned_ctx;
11956 struct perf_event *event;
11957 struct task_struct *parent = current;
11958 int inherited_all = 1;
11959 unsigned long flags;
11962 if (likely(!parent->perf_event_ctxp[ctxn]))
11966 * If the parent's context is a clone, pin it so it won't get
11967 * swapped under us.
11969 parent_ctx = perf_pin_task_context(parent, ctxn);
11974 * No need to check if parent_ctx != NULL here; since we saw
11975 * it non-NULL earlier, the only reason for it to become NULL
11976 * is if we exit, and since we're currently in the middle of
11977 * a fork we can't be exiting at the same time.
11981 * Lock the parent list. No need to lock the child - not PID
11982 * hashed yet and not running, so nobody can access it.
11984 mutex_lock(&parent_ctx->mutex);
11987 * We dont have to disable NMIs - we are only looking at
11988 * the list, not manipulating it:
11990 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11991 ret = inherit_task_group(event, parent, parent_ctx,
11992 child, ctxn, &inherited_all);
11998 * We can't hold ctx->lock when iterating the ->flexible_group list due
11999 * to allocations, but we need to prevent rotation because
12000 * rotate_ctx() will change the list from interrupt context.
12002 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12003 parent_ctx->rotate_disable = 1;
12004 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12006 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12007 ret = inherit_task_group(event, parent, parent_ctx,
12008 child, ctxn, &inherited_all);
12013 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12014 parent_ctx->rotate_disable = 0;
12016 child_ctx = child->perf_event_ctxp[ctxn];
12018 if (child_ctx && inherited_all) {
12020 * Mark the child context as a clone of the parent
12021 * context, or of whatever the parent is a clone of.
12023 * Note that if the parent is a clone, the holding of
12024 * parent_ctx->lock avoids it from being uncloned.
12026 cloned_ctx = parent_ctx->parent_ctx;
12028 child_ctx->parent_ctx = cloned_ctx;
12029 child_ctx->parent_gen = parent_ctx->parent_gen;
12031 child_ctx->parent_ctx = parent_ctx;
12032 child_ctx->parent_gen = parent_ctx->generation;
12034 get_ctx(child_ctx->parent_ctx);
12037 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12039 mutex_unlock(&parent_ctx->mutex);
12041 perf_unpin_context(parent_ctx);
12042 put_ctx(parent_ctx);
12048 * Initialize the perf_event context in task_struct
12050 int perf_event_init_task(struct task_struct *child)
12054 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12055 mutex_init(&child->perf_event_mutex);
12056 INIT_LIST_HEAD(&child->perf_event_list);
12058 for_each_task_context_nr(ctxn) {
12059 ret = perf_event_init_context(child, ctxn);
12061 perf_event_free_task(child);
12069 static void __init perf_event_init_all_cpus(void)
12071 struct swevent_htable *swhash;
12074 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12076 for_each_possible_cpu(cpu) {
12077 swhash = &per_cpu(swevent_htable, cpu);
12078 mutex_init(&swhash->hlist_mutex);
12079 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12081 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12082 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12084 #ifdef CONFIG_CGROUP_PERF
12085 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12087 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12091 static void perf_swevent_init_cpu(unsigned int cpu)
12093 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12095 mutex_lock(&swhash->hlist_mutex);
12096 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12097 struct swevent_hlist *hlist;
12099 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12101 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12103 mutex_unlock(&swhash->hlist_mutex);
12106 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12107 static void __perf_event_exit_context(void *__info)
12109 struct perf_event_context *ctx = __info;
12110 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12111 struct perf_event *event;
12113 raw_spin_lock(&ctx->lock);
12114 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12115 list_for_each_entry(event, &ctx->event_list, event_entry)
12116 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12117 raw_spin_unlock(&ctx->lock);
12120 static void perf_event_exit_cpu_context(int cpu)
12122 struct perf_cpu_context *cpuctx;
12123 struct perf_event_context *ctx;
12126 mutex_lock(&pmus_lock);
12127 list_for_each_entry(pmu, &pmus, entry) {
12128 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12129 ctx = &cpuctx->ctx;
12131 mutex_lock(&ctx->mutex);
12132 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12133 cpuctx->online = 0;
12134 mutex_unlock(&ctx->mutex);
12136 cpumask_clear_cpu(cpu, perf_online_mask);
12137 mutex_unlock(&pmus_lock);
12141 static void perf_event_exit_cpu_context(int cpu) { }
12145 int perf_event_init_cpu(unsigned int cpu)
12147 struct perf_cpu_context *cpuctx;
12148 struct perf_event_context *ctx;
12151 perf_swevent_init_cpu(cpu);
12153 mutex_lock(&pmus_lock);
12154 cpumask_set_cpu(cpu, perf_online_mask);
12155 list_for_each_entry(pmu, &pmus, entry) {
12156 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12157 ctx = &cpuctx->ctx;
12159 mutex_lock(&ctx->mutex);
12160 cpuctx->online = 1;
12161 mutex_unlock(&ctx->mutex);
12163 mutex_unlock(&pmus_lock);
12168 int perf_event_exit_cpu(unsigned int cpu)
12170 perf_event_exit_cpu_context(cpu);
12175 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12179 for_each_online_cpu(cpu)
12180 perf_event_exit_cpu(cpu);
12186 * Run the perf reboot notifier at the very last possible moment so that
12187 * the generic watchdog code runs as long as possible.
12189 static struct notifier_block perf_reboot_notifier = {
12190 .notifier_call = perf_reboot,
12191 .priority = INT_MIN,
12194 void __init perf_event_init(void)
12198 idr_init(&pmu_idr);
12200 perf_event_init_all_cpus();
12201 init_srcu_struct(&pmus_srcu);
12202 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12203 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12204 perf_pmu_register(&perf_task_clock, NULL, -1);
12205 perf_tp_register();
12206 perf_event_init_cpu(smp_processor_id());
12207 register_reboot_notifier(&perf_reboot_notifier);
12209 ret = init_hw_breakpoint();
12210 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12213 * Build time assertion that we keep the data_head at the intended
12214 * location. IOW, validation we got the __reserved[] size right.
12216 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12220 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12223 struct perf_pmu_events_attr *pmu_attr =
12224 container_of(attr, struct perf_pmu_events_attr, attr);
12226 if (pmu_attr->event_str)
12227 return sprintf(page, "%s\n", pmu_attr->event_str);
12231 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12233 static int __init perf_event_sysfs_init(void)
12238 mutex_lock(&pmus_lock);
12240 ret = bus_register(&pmu_bus);
12244 list_for_each_entry(pmu, &pmus, entry) {
12245 if (!pmu->name || pmu->type < 0)
12248 ret = pmu_dev_alloc(pmu);
12249 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12251 pmu_bus_running = 1;
12255 mutex_unlock(&pmus_lock);
12259 device_initcall(perf_event_sysfs_init);
12261 #ifdef CONFIG_CGROUP_PERF
12262 static struct cgroup_subsys_state *
12263 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12265 struct perf_cgroup *jc;
12267 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12269 return ERR_PTR(-ENOMEM);
12271 jc->info = alloc_percpu(struct perf_cgroup_info);
12274 return ERR_PTR(-ENOMEM);
12280 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12282 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12284 free_percpu(jc->info);
12288 static int __perf_cgroup_move(void *info)
12290 struct task_struct *task = info;
12292 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12297 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12299 struct task_struct *task;
12300 struct cgroup_subsys_state *css;
12302 cgroup_taskset_for_each(task, css, tset)
12303 task_function_call(task, __perf_cgroup_move, task);
12306 struct cgroup_subsys perf_event_cgrp_subsys = {
12307 .css_alloc = perf_cgroup_css_alloc,
12308 .css_free = perf_cgroup_css_free,
12309 .attach = perf_cgroup_attach,
12311 * Implicitly enable on dfl hierarchy so that perf events can
12312 * always be filtered by cgroup2 path as long as perf_event
12313 * controller is not mounted on a legacy hierarchy.
12315 .implicit_on_dfl = true,
12318 #endif /* CONFIG_CGROUP_PERF */