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);
5032 /* Assume it's not an event with inherit set. */
5033 u64 perf_event_pause(struct perf_event *event, bool reset)
5035 struct perf_event_context *ctx;
5038 ctx = perf_event_ctx_lock(event);
5039 WARN_ON_ONCE(event->attr.inherit);
5040 _perf_event_disable(event);
5041 count = local64_read(&event->count);
5043 local64_set(&event->count, 0);
5044 perf_event_ctx_unlock(event, ctx);
5048 EXPORT_SYMBOL_GPL(perf_event_pause);
5051 * Holding the top-level event's child_mutex means that any
5052 * descendant process that has inherited this event will block
5053 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5054 * task existence requirements of perf_event_enable/disable.
5056 static void perf_event_for_each_child(struct perf_event *event,
5057 void (*func)(struct perf_event *))
5059 struct perf_event *child;
5061 WARN_ON_ONCE(event->ctx->parent_ctx);
5063 mutex_lock(&event->child_mutex);
5065 list_for_each_entry(child, &event->child_list, child_list)
5067 mutex_unlock(&event->child_mutex);
5070 static void perf_event_for_each(struct perf_event *event,
5071 void (*func)(struct perf_event *))
5073 struct perf_event_context *ctx = event->ctx;
5074 struct perf_event *sibling;
5076 lockdep_assert_held(&ctx->mutex);
5078 event = event->group_leader;
5080 perf_event_for_each_child(event, func);
5081 for_each_sibling_event(sibling, event)
5082 perf_event_for_each_child(sibling, func);
5085 static void __perf_event_period(struct perf_event *event,
5086 struct perf_cpu_context *cpuctx,
5087 struct perf_event_context *ctx,
5090 u64 value = *((u64 *)info);
5093 if (event->attr.freq) {
5094 event->attr.sample_freq = value;
5096 event->attr.sample_period = value;
5097 event->hw.sample_period = value;
5100 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5102 perf_pmu_disable(ctx->pmu);
5104 * We could be throttled; unthrottle now to avoid the tick
5105 * trying to unthrottle while we already re-started the event.
5107 if (event->hw.interrupts == MAX_INTERRUPTS) {
5108 event->hw.interrupts = 0;
5109 perf_log_throttle(event, 1);
5111 event->pmu->stop(event, PERF_EF_UPDATE);
5114 local64_set(&event->hw.period_left, 0);
5117 event->pmu->start(event, PERF_EF_RELOAD);
5118 perf_pmu_enable(ctx->pmu);
5122 static int perf_event_check_period(struct perf_event *event, u64 value)
5124 return event->pmu->check_period(event, value);
5127 static int _perf_event_period(struct perf_event *event, u64 value)
5129 if (!is_sampling_event(event))
5135 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5138 if (perf_event_check_period(event, value))
5141 if (!event->attr.freq && (value & (1ULL << 63)))
5144 event_function_call(event, __perf_event_period, &value);
5149 int perf_event_period(struct perf_event *event, u64 value)
5151 struct perf_event_context *ctx;
5154 ctx = perf_event_ctx_lock(event);
5155 ret = _perf_event_period(event, value);
5156 perf_event_ctx_unlock(event, ctx);
5160 EXPORT_SYMBOL_GPL(perf_event_period);
5162 static const struct file_operations perf_fops;
5164 static inline int perf_fget_light(int fd, struct fd *p)
5166 struct fd f = fdget(fd);
5170 if (f.file->f_op != &perf_fops) {
5178 static int perf_event_set_output(struct perf_event *event,
5179 struct perf_event *output_event);
5180 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5181 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5182 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5183 struct perf_event_attr *attr);
5185 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5187 void (*func)(struct perf_event *);
5191 case PERF_EVENT_IOC_ENABLE:
5192 func = _perf_event_enable;
5194 case PERF_EVENT_IOC_DISABLE:
5195 func = _perf_event_disable;
5197 case PERF_EVENT_IOC_RESET:
5198 func = _perf_event_reset;
5201 case PERF_EVENT_IOC_REFRESH:
5202 return _perf_event_refresh(event, arg);
5204 case PERF_EVENT_IOC_PERIOD:
5208 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5211 return _perf_event_period(event, value);
5213 case PERF_EVENT_IOC_ID:
5215 u64 id = primary_event_id(event);
5217 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5222 case PERF_EVENT_IOC_SET_OUTPUT:
5226 struct perf_event *output_event;
5228 ret = perf_fget_light(arg, &output);
5231 output_event = output.file->private_data;
5232 ret = perf_event_set_output(event, output_event);
5235 ret = perf_event_set_output(event, NULL);
5240 case PERF_EVENT_IOC_SET_FILTER:
5241 return perf_event_set_filter(event, (void __user *)arg);
5243 case PERF_EVENT_IOC_SET_BPF:
5244 return perf_event_set_bpf_prog(event, arg);
5246 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5247 struct ring_buffer *rb;
5250 rb = rcu_dereference(event->rb);
5251 if (!rb || !rb->nr_pages) {
5255 rb_toggle_paused(rb, !!arg);
5260 case PERF_EVENT_IOC_QUERY_BPF:
5261 return perf_event_query_prog_array(event, (void __user *)arg);
5263 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5264 struct perf_event_attr new_attr;
5265 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5271 return perf_event_modify_attr(event, &new_attr);
5277 if (flags & PERF_IOC_FLAG_GROUP)
5278 perf_event_for_each(event, func);
5280 perf_event_for_each_child(event, func);
5285 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5287 struct perf_event *event = file->private_data;
5288 struct perf_event_context *ctx;
5291 ctx = perf_event_ctx_lock(event);
5292 ret = _perf_ioctl(event, cmd, arg);
5293 perf_event_ctx_unlock(event, ctx);
5298 #ifdef CONFIG_COMPAT
5299 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5302 switch (_IOC_NR(cmd)) {
5303 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5304 case _IOC_NR(PERF_EVENT_IOC_ID):
5305 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5306 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5307 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5308 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5309 cmd &= ~IOCSIZE_MASK;
5310 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5314 return perf_ioctl(file, cmd, arg);
5317 # define perf_compat_ioctl NULL
5320 int perf_event_task_enable(void)
5322 struct perf_event_context *ctx;
5323 struct perf_event *event;
5325 mutex_lock(¤t->perf_event_mutex);
5326 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5327 ctx = perf_event_ctx_lock(event);
5328 perf_event_for_each_child(event, _perf_event_enable);
5329 perf_event_ctx_unlock(event, ctx);
5331 mutex_unlock(¤t->perf_event_mutex);
5336 int perf_event_task_disable(void)
5338 struct perf_event_context *ctx;
5339 struct perf_event *event;
5341 mutex_lock(¤t->perf_event_mutex);
5342 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5343 ctx = perf_event_ctx_lock(event);
5344 perf_event_for_each_child(event, _perf_event_disable);
5345 perf_event_ctx_unlock(event, ctx);
5347 mutex_unlock(¤t->perf_event_mutex);
5352 static int perf_event_index(struct perf_event *event)
5354 if (event->hw.state & PERF_HES_STOPPED)
5357 if (event->state != PERF_EVENT_STATE_ACTIVE)
5360 return event->pmu->event_idx(event);
5363 static void calc_timer_values(struct perf_event *event,
5370 *now = perf_clock();
5371 ctx_time = event->shadow_ctx_time + *now;
5372 __perf_update_times(event, ctx_time, enabled, running);
5375 static void perf_event_init_userpage(struct perf_event *event)
5377 struct perf_event_mmap_page *userpg;
5378 struct ring_buffer *rb;
5381 rb = rcu_dereference(event->rb);
5385 userpg = rb->user_page;
5387 /* Allow new userspace to detect that bit 0 is deprecated */
5388 userpg->cap_bit0_is_deprecated = 1;
5389 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5390 userpg->data_offset = PAGE_SIZE;
5391 userpg->data_size = perf_data_size(rb);
5397 void __weak arch_perf_update_userpage(
5398 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5403 * Callers need to ensure there can be no nesting of this function, otherwise
5404 * the seqlock logic goes bad. We can not serialize this because the arch
5405 * code calls this from NMI context.
5407 void perf_event_update_userpage(struct perf_event *event)
5409 struct perf_event_mmap_page *userpg;
5410 struct ring_buffer *rb;
5411 u64 enabled, running, now;
5414 rb = rcu_dereference(event->rb);
5419 * compute total_time_enabled, total_time_running
5420 * based on snapshot values taken when the event
5421 * was last scheduled in.
5423 * we cannot simply called update_context_time()
5424 * because of locking issue as we can be called in
5427 calc_timer_values(event, &now, &enabled, &running);
5429 userpg = rb->user_page;
5431 * Disable preemption to guarantee consistent time stamps are stored to
5437 userpg->index = perf_event_index(event);
5438 userpg->offset = perf_event_count(event);
5440 userpg->offset -= local64_read(&event->hw.prev_count);
5442 userpg->time_enabled = enabled +
5443 atomic64_read(&event->child_total_time_enabled);
5445 userpg->time_running = running +
5446 atomic64_read(&event->child_total_time_running);
5448 arch_perf_update_userpage(event, userpg, now);
5456 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5458 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5460 struct perf_event *event = vmf->vma->vm_file->private_data;
5461 struct ring_buffer *rb;
5462 vm_fault_t ret = VM_FAULT_SIGBUS;
5464 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5465 if (vmf->pgoff == 0)
5471 rb = rcu_dereference(event->rb);
5475 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5478 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5482 get_page(vmf->page);
5483 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5484 vmf->page->index = vmf->pgoff;
5493 static void ring_buffer_attach(struct perf_event *event,
5494 struct ring_buffer *rb)
5496 struct ring_buffer *old_rb = NULL;
5497 unsigned long flags;
5501 * Should be impossible, we set this when removing
5502 * event->rb_entry and wait/clear when adding event->rb_entry.
5504 WARN_ON_ONCE(event->rcu_pending);
5507 spin_lock_irqsave(&old_rb->event_lock, flags);
5508 list_del_rcu(&event->rb_entry);
5509 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5511 event->rcu_batches = get_state_synchronize_rcu();
5512 event->rcu_pending = 1;
5516 if (event->rcu_pending) {
5517 cond_synchronize_rcu(event->rcu_batches);
5518 event->rcu_pending = 0;
5521 spin_lock_irqsave(&rb->event_lock, flags);
5522 list_add_rcu(&event->rb_entry, &rb->event_list);
5523 spin_unlock_irqrestore(&rb->event_lock, flags);
5527 * Avoid racing with perf_mmap_close(AUX): stop the event
5528 * before swizzling the event::rb pointer; if it's getting
5529 * unmapped, its aux_mmap_count will be 0 and it won't
5530 * restart. See the comment in __perf_pmu_output_stop().
5532 * Data will inevitably be lost when set_output is done in
5533 * mid-air, but then again, whoever does it like this is
5534 * not in for the data anyway.
5537 perf_event_stop(event, 0);
5539 rcu_assign_pointer(event->rb, rb);
5542 ring_buffer_put(old_rb);
5544 * Since we detached before setting the new rb, so that we
5545 * could attach the new rb, we could have missed a wakeup.
5548 wake_up_all(&event->waitq);
5552 static void ring_buffer_wakeup(struct perf_event *event)
5554 struct ring_buffer *rb;
5557 rb = rcu_dereference(event->rb);
5559 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5560 wake_up_all(&event->waitq);
5565 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5567 struct ring_buffer *rb;
5570 rb = rcu_dereference(event->rb);
5572 if (!refcount_inc_not_zero(&rb->refcount))
5580 void ring_buffer_put(struct ring_buffer *rb)
5582 if (!refcount_dec_and_test(&rb->refcount))
5585 WARN_ON_ONCE(!list_empty(&rb->event_list));
5587 call_rcu(&rb->rcu_head, rb_free_rcu);
5590 static void perf_mmap_open(struct vm_area_struct *vma)
5592 struct perf_event *event = vma->vm_file->private_data;
5594 atomic_inc(&event->mmap_count);
5595 atomic_inc(&event->rb->mmap_count);
5598 atomic_inc(&event->rb->aux_mmap_count);
5600 if (event->pmu->event_mapped)
5601 event->pmu->event_mapped(event, vma->vm_mm);
5604 static void perf_pmu_output_stop(struct perf_event *event);
5607 * A buffer can be mmap()ed multiple times; either directly through the same
5608 * event, or through other events by use of perf_event_set_output().
5610 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5611 * the buffer here, where we still have a VM context. This means we need
5612 * to detach all events redirecting to us.
5614 static void perf_mmap_close(struct vm_area_struct *vma)
5616 struct perf_event *event = vma->vm_file->private_data;
5618 struct ring_buffer *rb = ring_buffer_get(event);
5619 struct user_struct *mmap_user = rb->mmap_user;
5620 int mmap_locked = rb->mmap_locked;
5621 unsigned long size = perf_data_size(rb);
5623 if (event->pmu->event_unmapped)
5624 event->pmu->event_unmapped(event, vma->vm_mm);
5627 * rb->aux_mmap_count will always drop before rb->mmap_count and
5628 * event->mmap_count, so it is ok to use event->mmap_mutex to
5629 * serialize with perf_mmap here.
5631 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5632 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5634 * Stop all AUX events that are writing to this buffer,
5635 * so that we can free its AUX pages and corresponding PMU
5636 * data. Note that after rb::aux_mmap_count dropped to zero,
5637 * they won't start any more (see perf_aux_output_begin()).
5639 perf_pmu_output_stop(event);
5641 /* now it's safe to free the pages */
5642 if (!rb->aux_mmap_locked)
5643 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5645 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5647 /* this has to be the last one */
5649 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5651 mutex_unlock(&event->mmap_mutex);
5654 atomic_dec(&rb->mmap_count);
5656 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5659 ring_buffer_attach(event, NULL);
5660 mutex_unlock(&event->mmap_mutex);
5662 /* If there's still other mmap()s of this buffer, we're done. */
5663 if (atomic_read(&rb->mmap_count))
5667 * No other mmap()s, detach from all other events that might redirect
5668 * into the now unreachable buffer. Somewhat complicated by the
5669 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5673 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5674 if (!atomic_long_inc_not_zero(&event->refcount)) {
5676 * This event is en-route to free_event() which will
5677 * detach it and remove it from the list.
5683 mutex_lock(&event->mmap_mutex);
5685 * Check we didn't race with perf_event_set_output() which can
5686 * swizzle the rb from under us while we were waiting to
5687 * acquire mmap_mutex.
5689 * If we find a different rb; ignore this event, a next
5690 * iteration will no longer find it on the list. We have to
5691 * still restart the iteration to make sure we're not now
5692 * iterating the wrong list.
5694 if (event->rb == rb)
5695 ring_buffer_attach(event, NULL);
5697 mutex_unlock(&event->mmap_mutex);
5701 * Restart the iteration; either we're on the wrong list or
5702 * destroyed its integrity by doing a deletion.
5709 * It could be there's still a few 0-ref events on the list; they'll
5710 * get cleaned up by free_event() -- they'll also still have their
5711 * ref on the rb and will free it whenever they are done with it.
5713 * Aside from that, this buffer is 'fully' detached and unmapped,
5714 * undo the VM accounting.
5717 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5718 &mmap_user->locked_vm);
5719 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5720 free_uid(mmap_user);
5723 ring_buffer_put(rb); /* could be last */
5726 static const struct vm_operations_struct perf_mmap_vmops = {
5727 .open = perf_mmap_open,
5728 .close = perf_mmap_close, /* non mergeable */
5729 .fault = perf_mmap_fault,
5730 .page_mkwrite = perf_mmap_fault,
5733 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5735 struct perf_event *event = file->private_data;
5736 unsigned long user_locked, user_lock_limit;
5737 struct user_struct *user = current_user();
5738 unsigned long locked, lock_limit;
5739 struct ring_buffer *rb = NULL;
5740 unsigned long vma_size;
5741 unsigned long nr_pages;
5742 long user_extra = 0, extra = 0;
5743 int ret = 0, flags = 0;
5746 * Don't allow mmap() of inherited per-task counters. This would
5747 * create a performance issue due to all children writing to the
5750 if (event->cpu == -1 && event->attr.inherit)
5753 if (!(vma->vm_flags & VM_SHARED))
5756 vma_size = vma->vm_end - vma->vm_start;
5758 if (vma->vm_pgoff == 0) {
5759 nr_pages = (vma_size / PAGE_SIZE) - 1;
5762 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5763 * mapped, all subsequent mappings should have the same size
5764 * and offset. Must be above the normal perf buffer.
5766 u64 aux_offset, aux_size;
5771 nr_pages = vma_size / PAGE_SIZE;
5773 mutex_lock(&event->mmap_mutex);
5780 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5781 aux_size = READ_ONCE(rb->user_page->aux_size);
5783 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5786 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5789 /* already mapped with a different offset */
5790 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5793 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5796 /* already mapped with a different size */
5797 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5800 if (!is_power_of_2(nr_pages))
5803 if (!atomic_inc_not_zero(&rb->mmap_count))
5806 if (rb_has_aux(rb)) {
5807 atomic_inc(&rb->aux_mmap_count);
5812 atomic_set(&rb->aux_mmap_count, 1);
5813 user_extra = nr_pages;
5819 * If we have rb pages ensure they're a power-of-two number, so we
5820 * can do bitmasks instead of modulo.
5822 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5825 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5828 WARN_ON_ONCE(event->ctx->parent_ctx);
5830 mutex_lock(&event->mmap_mutex);
5832 if (event->rb->nr_pages != nr_pages) {
5837 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5839 * Raced against perf_mmap_close() through
5840 * perf_event_set_output(). Try again, hope for better
5843 mutex_unlock(&event->mmap_mutex);
5850 user_extra = nr_pages + 1;
5853 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5856 * Increase the limit linearly with more CPUs:
5858 user_lock_limit *= num_online_cpus();
5860 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5862 if (user_locked <= user_lock_limit) {
5863 /* charge all to locked_vm */
5864 } else if (atomic_long_read(&user->locked_vm) >= user_lock_limit) {
5865 /* charge all to pinned_vm */
5870 * charge locked_vm until it hits user_lock_limit;
5871 * charge the rest from pinned_vm
5873 extra = user_locked - user_lock_limit;
5874 user_extra -= extra;
5877 lock_limit = rlimit(RLIMIT_MEMLOCK);
5878 lock_limit >>= PAGE_SHIFT;
5879 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5881 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5882 !capable(CAP_IPC_LOCK)) {
5887 WARN_ON(!rb && event->rb);
5889 if (vma->vm_flags & VM_WRITE)
5890 flags |= RING_BUFFER_WRITABLE;
5893 rb = rb_alloc(nr_pages,
5894 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5902 atomic_set(&rb->mmap_count, 1);
5903 rb->mmap_user = get_current_user();
5904 rb->mmap_locked = extra;
5906 ring_buffer_attach(event, rb);
5908 perf_event_init_userpage(event);
5909 perf_event_update_userpage(event);
5911 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5912 event->attr.aux_watermark, flags);
5914 rb->aux_mmap_locked = extra;
5919 atomic_long_add(user_extra, &user->locked_vm);
5920 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5922 atomic_inc(&event->mmap_count);
5924 atomic_dec(&rb->mmap_count);
5927 mutex_unlock(&event->mmap_mutex);
5930 * Since pinned accounting is per vm we cannot allow fork() to copy our
5933 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5934 vma->vm_ops = &perf_mmap_vmops;
5936 if (event->pmu->event_mapped)
5937 event->pmu->event_mapped(event, vma->vm_mm);
5942 static int perf_fasync(int fd, struct file *filp, int on)
5944 struct inode *inode = file_inode(filp);
5945 struct perf_event *event = filp->private_data;
5949 retval = fasync_helper(fd, filp, on, &event->fasync);
5950 inode_unlock(inode);
5958 static const struct file_operations perf_fops = {
5959 .llseek = no_llseek,
5960 .release = perf_release,
5963 .unlocked_ioctl = perf_ioctl,
5964 .compat_ioctl = perf_compat_ioctl,
5966 .fasync = perf_fasync,
5972 * If there's data, ensure we set the poll() state and publish everything
5973 * to user-space before waking everybody up.
5976 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5978 /* only the parent has fasync state */
5980 event = event->parent;
5981 return &event->fasync;
5984 void perf_event_wakeup(struct perf_event *event)
5986 ring_buffer_wakeup(event);
5988 if (event->pending_kill) {
5989 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5990 event->pending_kill = 0;
5994 static void perf_pending_event_disable(struct perf_event *event)
5996 int cpu = READ_ONCE(event->pending_disable);
6001 if (cpu == smp_processor_id()) {
6002 WRITE_ONCE(event->pending_disable, -1);
6003 perf_event_disable_local(event);
6010 * perf_event_disable_inatomic()
6011 * @pending_disable = CPU-A;
6015 * @pending_disable = -1;
6018 * perf_event_disable_inatomic()
6019 * @pending_disable = CPU-B;
6020 * irq_work_queue(); // FAILS
6023 * perf_pending_event()
6025 * But the event runs on CPU-B and wants disabling there.
6027 irq_work_queue_on(&event->pending, cpu);
6030 static void perf_pending_event(struct irq_work *entry)
6032 struct perf_event *event = container_of(entry, struct perf_event, pending);
6035 rctx = perf_swevent_get_recursion_context();
6037 * If we 'fail' here, that's OK, it means recursion is already disabled
6038 * and we won't recurse 'further'.
6041 perf_pending_event_disable(event);
6043 if (event->pending_wakeup) {
6044 event->pending_wakeup = 0;
6045 perf_event_wakeup(event);
6049 perf_swevent_put_recursion_context(rctx);
6053 * We assume there is only KVM supporting the callbacks.
6054 * Later on, we might change it to a list if there is
6055 * another virtualization implementation supporting the callbacks.
6057 struct perf_guest_info_callbacks *perf_guest_cbs;
6059 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6061 perf_guest_cbs = cbs;
6064 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6066 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6068 perf_guest_cbs = NULL;
6071 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6074 perf_output_sample_regs(struct perf_output_handle *handle,
6075 struct pt_regs *regs, u64 mask)
6078 DECLARE_BITMAP(_mask, 64);
6080 bitmap_from_u64(_mask, mask);
6081 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6084 val = perf_reg_value(regs, bit);
6085 perf_output_put(handle, val);
6089 static void perf_sample_regs_user(struct perf_regs *regs_user,
6090 struct pt_regs *regs,
6091 struct pt_regs *regs_user_copy)
6093 if (user_mode(regs)) {
6094 regs_user->abi = perf_reg_abi(current);
6095 regs_user->regs = regs;
6096 } else if (!(current->flags & PF_KTHREAD)) {
6097 perf_get_regs_user(regs_user, regs, regs_user_copy);
6099 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6100 regs_user->regs = NULL;
6104 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6105 struct pt_regs *regs)
6107 regs_intr->regs = regs;
6108 regs_intr->abi = perf_reg_abi(current);
6113 * Get remaining task size from user stack pointer.
6115 * It'd be better to take stack vma map and limit this more
6116 * precisely, but there's no way to get it safely under interrupt,
6117 * so using TASK_SIZE as limit.
6119 static u64 perf_ustack_task_size(struct pt_regs *regs)
6121 unsigned long addr = perf_user_stack_pointer(regs);
6123 if (!addr || addr >= TASK_SIZE)
6126 return TASK_SIZE - addr;
6130 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6131 struct pt_regs *regs)
6135 /* No regs, no stack pointer, no dump. */
6140 * Check if we fit in with the requested stack size into the:
6142 * If we don't, we limit the size to the TASK_SIZE.
6144 * - remaining sample size
6145 * If we don't, we customize the stack size to
6146 * fit in to the remaining sample size.
6149 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6150 stack_size = min(stack_size, (u16) task_size);
6152 /* Current header size plus static size and dynamic size. */
6153 header_size += 2 * sizeof(u64);
6155 /* Do we fit in with the current stack dump size? */
6156 if ((u16) (header_size + stack_size) < header_size) {
6158 * If we overflow the maximum size for the sample,
6159 * we customize the stack dump size to fit in.
6161 stack_size = USHRT_MAX - header_size - sizeof(u64);
6162 stack_size = round_up(stack_size, sizeof(u64));
6169 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6170 struct pt_regs *regs)
6172 /* Case of a kernel thread, nothing to dump */
6175 perf_output_put(handle, size);
6185 * - the size requested by user or the best one we can fit
6186 * in to the sample max size
6188 * - user stack dump data
6190 * - the actual dumped size
6194 perf_output_put(handle, dump_size);
6197 sp = perf_user_stack_pointer(regs);
6200 rem = __output_copy_user(handle, (void *) sp, dump_size);
6202 dyn_size = dump_size - rem;
6204 perf_output_skip(handle, rem);
6207 perf_output_put(handle, dyn_size);
6211 static void __perf_event_header__init_id(struct perf_event_header *header,
6212 struct perf_sample_data *data,
6213 struct perf_event *event)
6215 u64 sample_type = event->attr.sample_type;
6217 data->type = sample_type;
6218 header->size += event->id_header_size;
6220 if (sample_type & PERF_SAMPLE_TID) {
6221 /* namespace issues */
6222 data->tid_entry.pid = perf_event_pid(event, current);
6223 data->tid_entry.tid = perf_event_tid(event, current);
6226 if (sample_type & PERF_SAMPLE_TIME)
6227 data->time = perf_event_clock(event);
6229 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6230 data->id = primary_event_id(event);
6232 if (sample_type & PERF_SAMPLE_STREAM_ID)
6233 data->stream_id = event->id;
6235 if (sample_type & PERF_SAMPLE_CPU) {
6236 data->cpu_entry.cpu = raw_smp_processor_id();
6237 data->cpu_entry.reserved = 0;
6241 void perf_event_header__init_id(struct perf_event_header *header,
6242 struct perf_sample_data *data,
6243 struct perf_event *event)
6245 if (event->attr.sample_id_all)
6246 __perf_event_header__init_id(header, data, event);
6249 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6250 struct perf_sample_data *data)
6252 u64 sample_type = data->type;
6254 if (sample_type & PERF_SAMPLE_TID)
6255 perf_output_put(handle, data->tid_entry);
6257 if (sample_type & PERF_SAMPLE_TIME)
6258 perf_output_put(handle, data->time);
6260 if (sample_type & PERF_SAMPLE_ID)
6261 perf_output_put(handle, data->id);
6263 if (sample_type & PERF_SAMPLE_STREAM_ID)
6264 perf_output_put(handle, data->stream_id);
6266 if (sample_type & PERF_SAMPLE_CPU)
6267 perf_output_put(handle, data->cpu_entry);
6269 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6270 perf_output_put(handle, data->id);
6273 void perf_event__output_id_sample(struct perf_event *event,
6274 struct perf_output_handle *handle,
6275 struct perf_sample_data *sample)
6277 if (event->attr.sample_id_all)
6278 __perf_event__output_id_sample(handle, sample);
6281 static void perf_output_read_one(struct perf_output_handle *handle,
6282 struct perf_event *event,
6283 u64 enabled, u64 running)
6285 u64 read_format = event->attr.read_format;
6289 values[n++] = perf_event_count(event);
6290 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6291 values[n++] = enabled +
6292 atomic64_read(&event->child_total_time_enabled);
6294 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6295 values[n++] = running +
6296 atomic64_read(&event->child_total_time_running);
6298 if (read_format & PERF_FORMAT_ID)
6299 values[n++] = primary_event_id(event);
6301 __output_copy(handle, values, n * sizeof(u64));
6304 static void perf_output_read_group(struct perf_output_handle *handle,
6305 struct perf_event *event,
6306 u64 enabled, u64 running)
6308 struct perf_event *leader = event->group_leader, *sub;
6309 u64 read_format = event->attr.read_format;
6313 values[n++] = 1 + leader->nr_siblings;
6315 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6316 values[n++] = enabled;
6318 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6319 values[n++] = running;
6321 if ((leader != event) &&
6322 (leader->state == PERF_EVENT_STATE_ACTIVE))
6323 leader->pmu->read(leader);
6325 values[n++] = perf_event_count(leader);
6326 if (read_format & PERF_FORMAT_ID)
6327 values[n++] = primary_event_id(leader);
6329 __output_copy(handle, values, n * sizeof(u64));
6331 for_each_sibling_event(sub, leader) {
6334 if ((sub != event) &&
6335 (sub->state == PERF_EVENT_STATE_ACTIVE))
6336 sub->pmu->read(sub);
6338 values[n++] = perf_event_count(sub);
6339 if (read_format & PERF_FORMAT_ID)
6340 values[n++] = primary_event_id(sub);
6342 __output_copy(handle, values, n * sizeof(u64));
6346 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6347 PERF_FORMAT_TOTAL_TIME_RUNNING)
6350 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6352 * The problem is that its both hard and excessively expensive to iterate the
6353 * child list, not to mention that its impossible to IPI the children running
6354 * on another CPU, from interrupt/NMI context.
6356 static void perf_output_read(struct perf_output_handle *handle,
6357 struct perf_event *event)
6359 u64 enabled = 0, running = 0, now;
6360 u64 read_format = event->attr.read_format;
6363 * compute total_time_enabled, total_time_running
6364 * based on snapshot values taken when the event
6365 * was last scheduled in.
6367 * we cannot simply called update_context_time()
6368 * because of locking issue as we are called in
6371 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6372 calc_timer_values(event, &now, &enabled, &running);
6374 if (event->attr.read_format & PERF_FORMAT_GROUP)
6375 perf_output_read_group(handle, event, enabled, running);
6377 perf_output_read_one(handle, event, enabled, running);
6380 void perf_output_sample(struct perf_output_handle *handle,
6381 struct perf_event_header *header,
6382 struct perf_sample_data *data,
6383 struct perf_event *event)
6385 u64 sample_type = data->type;
6387 perf_output_put(handle, *header);
6389 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6390 perf_output_put(handle, data->id);
6392 if (sample_type & PERF_SAMPLE_IP)
6393 perf_output_put(handle, data->ip);
6395 if (sample_type & PERF_SAMPLE_TID)
6396 perf_output_put(handle, data->tid_entry);
6398 if (sample_type & PERF_SAMPLE_TIME)
6399 perf_output_put(handle, data->time);
6401 if (sample_type & PERF_SAMPLE_ADDR)
6402 perf_output_put(handle, data->addr);
6404 if (sample_type & PERF_SAMPLE_ID)
6405 perf_output_put(handle, data->id);
6407 if (sample_type & PERF_SAMPLE_STREAM_ID)
6408 perf_output_put(handle, data->stream_id);
6410 if (sample_type & PERF_SAMPLE_CPU)
6411 perf_output_put(handle, data->cpu_entry);
6413 if (sample_type & PERF_SAMPLE_PERIOD)
6414 perf_output_put(handle, data->period);
6416 if (sample_type & PERF_SAMPLE_READ)
6417 perf_output_read(handle, event);
6419 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6422 size += data->callchain->nr;
6423 size *= sizeof(u64);
6424 __output_copy(handle, data->callchain, size);
6427 if (sample_type & PERF_SAMPLE_RAW) {
6428 struct perf_raw_record *raw = data->raw;
6431 struct perf_raw_frag *frag = &raw->frag;
6433 perf_output_put(handle, raw->size);
6436 __output_custom(handle, frag->copy,
6437 frag->data, frag->size);
6439 __output_copy(handle, frag->data,
6442 if (perf_raw_frag_last(frag))
6447 __output_skip(handle, NULL, frag->pad);
6453 .size = sizeof(u32),
6456 perf_output_put(handle, raw);
6460 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6461 if (data->br_stack) {
6464 size = data->br_stack->nr
6465 * sizeof(struct perf_branch_entry);
6467 perf_output_put(handle, data->br_stack->nr);
6468 perf_output_copy(handle, data->br_stack->entries, size);
6471 * we always store at least the value of nr
6474 perf_output_put(handle, nr);
6478 if (sample_type & PERF_SAMPLE_REGS_USER) {
6479 u64 abi = data->regs_user.abi;
6482 * If there are no regs to dump, notice it through
6483 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6485 perf_output_put(handle, abi);
6488 u64 mask = event->attr.sample_regs_user;
6489 perf_output_sample_regs(handle,
6490 data->regs_user.regs,
6495 if (sample_type & PERF_SAMPLE_STACK_USER) {
6496 perf_output_sample_ustack(handle,
6497 data->stack_user_size,
6498 data->regs_user.regs);
6501 if (sample_type & PERF_SAMPLE_WEIGHT)
6502 perf_output_put(handle, data->weight);
6504 if (sample_type & PERF_SAMPLE_DATA_SRC)
6505 perf_output_put(handle, data->data_src.val);
6507 if (sample_type & PERF_SAMPLE_TRANSACTION)
6508 perf_output_put(handle, data->txn);
6510 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6511 u64 abi = data->regs_intr.abi;
6513 * If there are no regs to dump, notice it through
6514 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6516 perf_output_put(handle, abi);
6519 u64 mask = event->attr.sample_regs_intr;
6521 perf_output_sample_regs(handle,
6522 data->regs_intr.regs,
6527 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6528 perf_output_put(handle, data->phys_addr);
6530 if (!event->attr.watermark) {
6531 int wakeup_events = event->attr.wakeup_events;
6533 if (wakeup_events) {
6534 struct ring_buffer *rb = handle->rb;
6535 int events = local_inc_return(&rb->events);
6537 if (events >= wakeup_events) {
6538 local_sub(wakeup_events, &rb->events);
6539 local_inc(&rb->wakeup);
6545 static u64 perf_virt_to_phys(u64 virt)
6548 struct page *p = NULL;
6553 if (virt >= TASK_SIZE) {
6554 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6555 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6556 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6557 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6560 * Walking the pages tables for user address.
6561 * Interrupts are disabled, so it prevents any tear down
6562 * of the page tables.
6563 * Try IRQ-safe __get_user_pages_fast first.
6564 * If failed, leave phys_addr as 0.
6566 if ((current->mm != NULL) &&
6567 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6568 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6577 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6579 struct perf_callchain_entry *
6580 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6582 bool kernel = !event->attr.exclude_callchain_kernel;
6583 bool user = !event->attr.exclude_callchain_user;
6584 /* Disallow cross-task user callchains. */
6585 bool crosstask = event->ctx->task && event->ctx->task != current;
6586 const u32 max_stack = event->attr.sample_max_stack;
6587 struct perf_callchain_entry *callchain;
6589 if (!kernel && !user)
6590 return &__empty_callchain;
6592 callchain = get_perf_callchain(regs, 0, kernel, user,
6593 max_stack, crosstask, true);
6594 return callchain ?: &__empty_callchain;
6597 void perf_prepare_sample(struct perf_event_header *header,
6598 struct perf_sample_data *data,
6599 struct perf_event *event,
6600 struct pt_regs *regs)
6602 u64 sample_type = event->attr.sample_type;
6604 header->type = PERF_RECORD_SAMPLE;
6605 header->size = sizeof(*header) + event->header_size;
6608 header->misc |= perf_misc_flags(regs);
6610 __perf_event_header__init_id(header, data, event);
6612 if (sample_type & PERF_SAMPLE_IP)
6613 data->ip = perf_instruction_pointer(regs);
6615 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6618 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6619 data->callchain = perf_callchain(event, regs);
6621 size += data->callchain->nr;
6623 header->size += size * sizeof(u64);
6626 if (sample_type & PERF_SAMPLE_RAW) {
6627 struct perf_raw_record *raw = data->raw;
6631 struct perf_raw_frag *frag = &raw->frag;
6636 if (perf_raw_frag_last(frag))
6641 size = round_up(sum + sizeof(u32), sizeof(u64));
6642 raw->size = size - sizeof(u32);
6643 frag->pad = raw->size - sum;
6648 header->size += size;
6651 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6652 int size = sizeof(u64); /* nr */
6653 if (data->br_stack) {
6654 size += data->br_stack->nr
6655 * sizeof(struct perf_branch_entry);
6657 header->size += size;
6660 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6661 perf_sample_regs_user(&data->regs_user, regs,
6662 &data->regs_user_copy);
6664 if (sample_type & PERF_SAMPLE_REGS_USER) {
6665 /* regs dump ABI info */
6666 int size = sizeof(u64);
6668 if (data->regs_user.regs) {
6669 u64 mask = event->attr.sample_regs_user;
6670 size += hweight64(mask) * sizeof(u64);
6673 header->size += size;
6676 if (sample_type & PERF_SAMPLE_STACK_USER) {
6678 * Either we need PERF_SAMPLE_STACK_USER bit to be always
6679 * processed as the last one or have additional check added
6680 * in case new sample type is added, because we could eat
6681 * up the rest of the sample size.
6683 u16 stack_size = event->attr.sample_stack_user;
6684 u16 size = sizeof(u64);
6686 stack_size = perf_sample_ustack_size(stack_size, header->size,
6687 data->regs_user.regs);
6690 * If there is something to dump, add space for the dump
6691 * itself and for the field that tells the dynamic size,
6692 * which is how many have been actually dumped.
6695 size += sizeof(u64) + stack_size;
6697 data->stack_user_size = stack_size;
6698 header->size += size;
6701 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6702 /* regs dump ABI info */
6703 int size = sizeof(u64);
6705 perf_sample_regs_intr(&data->regs_intr, regs);
6707 if (data->regs_intr.regs) {
6708 u64 mask = event->attr.sample_regs_intr;
6710 size += hweight64(mask) * sizeof(u64);
6713 header->size += size;
6716 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6717 data->phys_addr = perf_virt_to_phys(data->addr);
6720 static __always_inline int
6721 __perf_event_output(struct perf_event *event,
6722 struct perf_sample_data *data,
6723 struct pt_regs *regs,
6724 int (*output_begin)(struct perf_output_handle *,
6725 struct perf_event *,
6728 struct perf_output_handle handle;
6729 struct perf_event_header header;
6732 /* protect the callchain buffers */
6735 perf_prepare_sample(&header, data, event, regs);
6737 err = output_begin(&handle, event, header.size);
6741 perf_output_sample(&handle, &header, data, event);
6743 perf_output_end(&handle);
6751 perf_event_output_forward(struct perf_event *event,
6752 struct perf_sample_data *data,
6753 struct pt_regs *regs)
6755 __perf_event_output(event, data, regs, perf_output_begin_forward);
6759 perf_event_output_backward(struct perf_event *event,
6760 struct perf_sample_data *data,
6761 struct pt_regs *regs)
6763 __perf_event_output(event, data, regs, perf_output_begin_backward);
6767 perf_event_output(struct perf_event *event,
6768 struct perf_sample_data *data,
6769 struct pt_regs *regs)
6771 return __perf_event_output(event, data, regs, perf_output_begin);
6778 struct perf_read_event {
6779 struct perf_event_header header;
6786 perf_event_read_event(struct perf_event *event,
6787 struct task_struct *task)
6789 struct perf_output_handle handle;
6790 struct perf_sample_data sample;
6791 struct perf_read_event read_event = {
6793 .type = PERF_RECORD_READ,
6795 .size = sizeof(read_event) + event->read_size,
6797 .pid = perf_event_pid(event, task),
6798 .tid = perf_event_tid(event, task),
6802 perf_event_header__init_id(&read_event.header, &sample, event);
6803 ret = perf_output_begin(&handle, event, read_event.header.size);
6807 perf_output_put(&handle, read_event);
6808 perf_output_read(&handle, event);
6809 perf_event__output_id_sample(event, &handle, &sample);
6811 perf_output_end(&handle);
6814 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6817 perf_iterate_ctx(struct perf_event_context *ctx,
6818 perf_iterate_f output,
6819 void *data, bool all)
6821 struct perf_event *event;
6823 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6825 if (event->state < PERF_EVENT_STATE_INACTIVE)
6827 if (!event_filter_match(event))
6831 output(event, data);
6835 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6837 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6838 struct perf_event *event;
6840 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6842 * Skip events that are not fully formed yet; ensure that
6843 * if we observe event->ctx, both event and ctx will be
6844 * complete enough. See perf_install_in_context().
6846 if (!smp_load_acquire(&event->ctx))
6849 if (event->state < PERF_EVENT_STATE_INACTIVE)
6851 if (!event_filter_match(event))
6853 output(event, data);
6858 * Iterate all events that need to receive side-band events.
6860 * For new callers; ensure that account_pmu_sb_event() includes
6861 * your event, otherwise it might not get delivered.
6864 perf_iterate_sb(perf_iterate_f output, void *data,
6865 struct perf_event_context *task_ctx)
6867 struct perf_event_context *ctx;
6874 * If we have task_ctx != NULL we only notify the task context itself.
6875 * The task_ctx is set only for EXIT events before releasing task
6879 perf_iterate_ctx(task_ctx, output, data, false);
6883 perf_iterate_sb_cpu(output, data);
6885 for_each_task_context_nr(ctxn) {
6886 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6888 perf_iterate_ctx(ctx, output, data, false);
6896 * Clear all file-based filters at exec, they'll have to be
6897 * re-instated when/if these objects are mmapped again.
6899 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6901 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6902 struct perf_addr_filter *filter;
6903 unsigned int restart = 0, count = 0;
6904 unsigned long flags;
6906 if (!has_addr_filter(event))
6909 raw_spin_lock_irqsave(&ifh->lock, flags);
6910 list_for_each_entry(filter, &ifh->list, entry) {
6911 if (filter->path.dentry) {
6912 event->addr_filter_ranges[count].start = 0;
6913 event->addr_filter_ranges[count].size = 0;
6921 event->addr_filters_gen++;
6922 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6925 perf_event_stop(event, 1);
6928 void perf_event_exec(void)
6930 struct perf_event_context *ctx;
6934 for_each_task_context_nr(ctxn) {
6935 ctx = current->perf_event_ctxp[ctxn];
6939 perf_event_enable_on_exec(ctxn);
6941 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6947 struct remote_output {
6948 struct ring_buffer *rb;
6952 static void __perf_event_output_stop(struct perf_event *event, void *data)
6954 struct perf_event *parent = event->parent;
6955 struct remote_output *ro = data;
6956 struct ring_buffer *rb = ro->rb;
6957 struct stop_event_data sd = {
6961 if (!has_aux(event))
6968 * In case of inheritance, it will be the parent that links to the
6969 * ring-buffer, but it will be the child that's actually using it.
6971 * We are using event::rb to determine if the event should be stopped,
6972 * however this may race with ring_buffer_attach() (through set_output),
6973 * which will make us skip the event that actually needs to be stopped.
6974 * So ring_buffer_attach() has to stop an aux event before re-assigning
6977 if (rcu_dereference(parent->rb) == rb)
6978 ro->err = __perf_event_stop(&sd);
6981 static int __perf_pmu_output_stop(void *info)
6983 struct perf_event *event = info;
6984 struct pmu *pmu = event->ctx->pmu;
6985 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6986 struct remote_output ro = {
6991 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6992 if (cpuctx->task_ctx)
6993 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7000 static void perf_pmu_output_stop(struct perf_event *event)
7002 struct perf_event *iter;
7007 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7009 * For per-CPU events, we need to make sure that neither they
7010 * nor their children are running; for cpu==-1 events it's
7011 * sufficient to stop the event itself if it's active, since
7012 * it can't have children.
7016 cpu = READ_ONCE(iter->oncpu);
7021 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7022 if (err == -EAGAIN) {
7031 * task tracking -- fork/exit
7033 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7036 struct perf_task_event {
7037 struct task_struct *task;
7038 struct perf_event_context *task_ctx;
7041 struct perf_event_header header;
7051 static int perf_event_task_match(struct perf_event *event)
7053 return event->attr.comm || event->attr.mmap ||
7054 event->attr.mmap2 || event->attr.mmap_data ||
7058 static void perf_event_task_output(struct perf_event *event,
7061 struct perf_task_event *task_event = data;
7062 struct perf_output_handle handle;
7063 struct perf_sample_data sample;
7064 struct task_struct *task = task_event->task;
7065 int ret, size = task_event->event_id.header.size;
7067 if (!perf_event_task_match(event))
7070 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7072 ret = perf_output_begin(&handle, event,
7073 task_event->event_id.header.size);
7077 task_event->event_id.pid = perf_event_pid(event, task);
7078 task_event->event_id.ppid = perf_event_pid(event, current);
7080 task_event->event_id.tid = perf_event_tid(event, task);
7081 task_event->event_id.ptid = perf_event_tid(event, current);
7083 task_event->event_id.time = perf_event_clock(event);
7085 perf_output_put(&handle, task_event->event_id);
7087 perf_event__output_id_sample(event, &handle, &sample);
7089 perf_output_end(&handle);
7091 task_event->event_id.header.size = size;
7094 static void perf_event_task(struct task_struct *task,
7095 struct perf_event_context *task_ctx,
7098 struct perf_task_event task_event;
7100 if (!atomic_read(&nr_comm_events) &&
7101 !atomic_read(&nr_mmap_events) &&
7102 !atomic_read(&nr_task_events))
7105 task_event = (struct perf_task_event){
7107 .task_ctx = task_ctx,
7110 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7112 .size = sizeof(task_event.event_id),
7122 perf_iterate_sb(perf_event_task_output,
7127 void perf_event_fork(struct task_struct *task)
7129 perf_event_task(task, NULL, 1);
7130 perf_event_namespaces(task);
7137 struct perf_comm_event {
7138 struct task_struct *task;
7143 struct perf_event_header header;
7150 static int perf_event_comm_match(struct perf_event *event)
7152 return event->attr.comm;
7155 static void perf_event_comm_output(struct perf_event *event,
7158 struct perf_comm_event *comm_event = data;
7159 struct perf_output_handle handle;
7160 struct perf_sample_data sample;
7161 int size = comm_event->event_id.header.size;
7164 if (!perf_event_comm_match(event))
7167 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7168 ret = perf_output_begin(&handle, event,
7169 comm_event->event_id.header.size);
7174 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7175 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7177 perf_output_put(&handle, comm_event->event_id);
7178 __output_copy(&handle, comm_event->comm,
7179 comm_event->comm_size);
7181 perf_event__output_id_sample(event, &handle, &sample);
7183 perf_output_end(&handle);
7185 comm_event->event_id.header.size = size;
7188 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7190 char comm[TASK_COMM_LEN];
7193 memset(comm, 0, sizeof(comm));
7194 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7195 size = ALIGN(strlen(comm)+1, sizeof(u64));
7197 comm_event->comm = comm;
7198 comm_event->comm_size = size;
7200 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7202 perf_iterate_sb(perf_event_comm_output,
7207 void perf_event_comm(struct task_struct *task, bool exec)
7209 struct perf_comm_event comm_event;
7211 if (!atomic_read(&nr_comm_events))
7214 comm_event = (struct perf_comm_event){
7220 .type = PERF_RECORD_COMM,
7221 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7229 perf_event_comm_event(&comm_event);
7233 * namespaces tracking
7236 struct perf_namespaces_event {
7237 struct task_struct *task;
7240 struct perf_event_header header;
7245 struct perf_ns_link_info link_info[NR_NAMESPACES];
7249 static int perf_event_namespaces_match(struct perf_event *event)
7251 return event->attr.namespaces;
7254 static void perf_event_namespaces_output(struct perf_event *event,
7257 struct perf_namespaces_event *namespaces_event = data;
7258 struct perf_output_handle handle;
7259 struct perf_sample_data sample;
7260 u16 header_size = namespaces_event->event_id.header.size;
7263 if (!perf_event_namespaces_match(event))
7266 perf_event_header__init_id(&namespaces_event->event_id.header,
7268 ret = perf_output_begin(&handle, event,
7269 namespaces_event->event_id.header.size);
7273 namespaces_event->event_id.pid = perf_event_pid(event,
7274 namespaces_event->task);
7275 namespaces_event->event_id.tid = perf_event_tid(event,
7276 namespaces_event->task);
7278 perf_output_put(&handle, namespaces_event->event_id);
7280 perf_event__output_id_sample(event, &handle, &sample);
7282 perf_output_end(&handle);
7284 namespaces_event->event_id.header.size = header_size;
7287 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7288 struct task_struct *task,
7289 const struct proc_ns_operations *ns_ops)
7291 struct path ns_path;
7292 struct inode *ns_inode;
7295 error = ns_get_path(&ns_path, task, ns_ops);
7297 ns_inode = ns_path.dentry->d_inode;
7298 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7299 ns_link_info->ino = ns_inode->i_ino;
7304 void perf_event_namespaces(struct task_struct *task)
7306 struct perf_namespaces_event namespaces_event;
7307 struct perf_ns_link_info *ns_link_info;
7309 if (!atomic_read(&nr_namespaces_events))
7312 namespaces_event = (struct perf_namespaces_event){
7316 .type = PERF_RECORD_NAMESPACES,
7318 .size = sizeof(namespaces_event.event_id),
7322 .nr_namespaces = NR_NAMESPACES,
7323 /* .link_info[NR_NAMESPACES] */
7327 ns_link_info = namespaces_event.event_id.link_info;
7329 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7330 task, &mntns_operations);
7332 #ifdef CONFIG_USER_NS
7333 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7334 task, &userns_operations);
7336 #ifdef CONFIG_NET_NS
7337 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7338 task, &netns_operations);
7340 #ifdef CONFIG_UTS_NS
7341 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7342 task, &utsns_operations);
7344 #ifdef CONFIG_IPC_NS
7345 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7346 task, &ipcns_operations);
7348 #ifdef CONFIG_PID_NS
7349 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7350 task, &pidns_operations);
7352 #ifdef CONFIG_CGROUPS
7353 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7354 task, &cgroupns_operations);
7357 perf_iterate_sb(perf_event_namespaces_output,
7366 struct perf_mmap_event {
7367 struct vm_area_struct *vma;
7369 const char *file_name;
7377 struct perf_event_header header;
7387 static int perf_event_mmap_match(struct perf_event *event,
7390 struct perf_mmap_event *mmap_event = data;
7391 struct vm_area_struct *vma = mmap_event->vma;
7392 int executable = vma->vm_flags & VM_EXEC;
7394 return (!executable && event->attr.mmap_data) ||
7395 (executable && (event->attr.mmap || event->attr.mmap2));
7398 static void perf_event_mmap_output(struct perf_event *event,
7401 struct perf_mmap_event *mmap_event = data;
7402 struct perf_output_handle handle;
7403 struct perf_sample_data sample;
7404 int size = mmap_event->event_id.header.size;
7405 u32 type = mmap_event->event_id.header.type;
7408 if (!perf_event_mmap_match(event, data))
7411 if (event->attr.mmap2) {
7412 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7413 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7414 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7415 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7416 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7417 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7418 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7421 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7422 ret = perf_output_begin(&handle, event,
7423 mmap_event->event_id.header.size);
7427 mmap_event->event_id.pid = perf_event_pid(event, current);
7428 mmap_event->event_id.tid = perf_event_tid(event, current);
7430 perf_output_put(&handle, mmap_event->event_id);
7432 if (event->attr.mmap2) {
7433 perf_output_put(&handle, mmap_event->maj);
7434 perf_output_put(&handle, mmap_event->min);
7435 perf_output_put(&handle, mmap_event->ino);
7436 perf_output_put(&handle, mmap_event->ino_generation);
7437 perf_output_put(&handle, mmap_event->prot);
7438 perf_output_put(&handle, mmap_event->flags);
7441 __output_copy(&handle, mmap_event->file_name,
7442 mmap_event->file_size);
7444 perf_event__output_id_sample(event, &handle, &sample);
7446 perf_output_end(&handle);
7448 mmap_event->event_id.header.size = size;
7449 mmap_event->event_id.header.type = type;
7452 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7454 struct vm_area_struct *vma = mmap_event->vma;
7455 struct file *file = vma->vm_file;
7456 int maj = 0, min = 0;
7457 u64 ino = 0, gen = 0;
7458 u32 prot = 0, flags = 0;
7464 if (vma->vm_flags & VM_READ)
7466 if (vma->vm_flags & VM_WRITE)
7468 if (vma->vm_flags & VM_EXEC)
7471 if (vma->vm_flags & VM_MAYSHARE)
7474 flags = MAP_PRIVATE;
7476 if (vma->vm_flags & VM_DENYWRITE)
7477 flags |= MAP_DENYWRITE;
7478 if (vma->vm_flags & VM_MAYEXEC)
7479 flags |= MAP_EXECUTABLE;
7480 if (vma->vm_flags & VM_LOCKED)
7481 flags |= MAP_LOCKED;
7482 if (vma->vm_flags & VM_HUGETLB)
7483 flags |= MAP_HUGETLB;
7486 struct inode *inode;
7489 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7495 * d_path() works from the end of the rb backwards, so we
7496 * need to add enough zero bytes after the string to handle
7497 * the 64bit alignment we do later.
7499 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7504 inode = file_inode(vma->vm_file);
7505 dev = inode->i_sb->s_dev;
7507 gen = inode->i_generation;
7513 if (vma->vm_ops && vma->vm_ops->name) {
7514 name = (char *) vma->vm_ops->name(vma);
7519 name = (char *)arch_vma_name(vma);
7523 if (vma->vm_start <= vma->vm_mm->start_brk &&
7524 vma->vm_end >= vma->vm_mm->brk) {
7528 if (vma->vm_start <= vma->vm_mm->start_stack &&
7529 vma->vm_end >= vma->vm_mm->start_stack) {
7539 strlcpy(tmp, name, sizeof(tmp));
7543 * Since our buffer works in 8 byte units we need to align our string
7544 * size to a multiple of 8. However, we must guarantee the tail end is
7545 * zero'd out to avoid leaking random bits to userspace.
7547 size = strlen(name)+1;
7548 while (!IS_ALIGNED(size, sizeof(u64)))
7549 name[size++] = '\0';
7551 mmap_event->file_name = name;
7552 mmap_event->file_size = size;
7553 mmap_event->maj = maj;
7554 mmap_event->min = min;
7555 mmap_event->ino = ino;
7556 mmap_event->ino_generation = gen;
7557 mmap_event->prot = prot;
7558 mmap_event->flags = flags;
7560 if (!(vma->vm_flags & VM_EXEC))
7561 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7563 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7565 perf_iterate_sb(perf_event_mmap_output,
7573 * Check whether inode and address range match filter criteria.
7575 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7576 struct file *file, unsigned long offset,
7579 /* d_inode(NULL) won't be equal to any mapped user-space file */
7580 if (!filter->path.dentry)
7583 if (d_inode(filter->path.dentry) != file_inode(file))
7586 if (filter->offset > offset + size)
7589 if (filter->offset + filter->size < offset)
7595 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7596 struct vm_area_struct *vma,
7597 struct perf_addr_filter_range *fr)
7599 unsigned long vma_size = vma->vm_end - vma->vm_start;
7600 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7601 struct file *file = vma->vm_file;
7603 if (!perf_addr_filter_match(filter, file, off, vma_size))
7606 if (filter->offset < off) {
7607 fr->start = vma->vm_start;
7608 fr->size = min(vma_size, filter->size - (off - filter->offset));
7610 fr->start = vma->vm_start + filter->offset - off;
7611 fr->size = min(vma->vm_end - fr->start, filter->size);
7617 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7619 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7620 struct vm_area_struct *vma = data;
7621 struct perf_addr_filter *filter;
7622 unsigned int restart = 0, count = 0;
7623 unsigned long flags;
7625 if (!has_addr_filter(event))
7631 raw_spin_lock_irqsave(&ifh->lock, flags);
7632 list_for_each_entry(filter, &ifh->list, entry) {
7633 if (perf_addr_filter_vma_adjust(filter, vma,
7634 &event->addr_filter_ranges[count]))
7641 event->addr_filters_gen++;
7642 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7645 perf_event_stop(event, 1);
7649 * Adjust all task's events' filters to the new vma
7651 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7653 struct perf_event_context *ctx;
7657 * Data tracing isn't supported yet and as such there is no need
7658 * to keep track of anything that isn't related to executable code:
7660 if (!(vma->vm_flags & VM_EXEC))
7664 for_each_task_context_nr(ctxn) {
7665 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7669 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7674 void perf_event_mmap(struct vm_area_struct *vma)
7676 struct perf_mmap_event mmap_event;
7678 if (!atomic_read(&nr_mmap_events))
7681 mmap_event = (struct perf_mmap_event){
7687 .type = PERF_RECORD_MMAP,
7688 .misc = PERF_RECORD_MISC_USER,
7693 .start = vma->vm_start,
7694 .len = vma->vm_end - vma->vm_start,
7695 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7697 /* .maj (attr_mmap2 only) */
7698 /* .min (attr_mmap2 only) */
7699 /* .ino (attr_mmap2 only) */
7700 /* .ino_generation (attr_mmap2 only) */
7701 /* .prot (attr_mmap2 only) */
7702 /* .flags (attr_mmap2 only) */
7705 perf_addr_filters_adjust(vma);
7706 perf_event_mmap_event(&mmap_event);
7709 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7710 unsigned long size, u64 flags)
7712 struct perf_output_handle handle;
7713 struct perf_sample_data sample;
7714 struct perf_aux_event {
7715 struct perf_event_header header;
7721 .type = PERF_RECORD_AUX,
7723 .size = sizeof(rec),
7731 perf_event_header__init_id(&rec.header, &sample, event);
7732 ret = perf_output_begin(&handle, event, rec.header.size);
7737 perf_output_put(&handle, rec);
7738 perf_event__output_id_sample(event, &handle, &sample);
7740 perf_output_end(&handle);
7744 * Lost/dropped samples logging
7746 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7748 struct perf_output_handle handle;
7749 struct perf_sample_data sample;
7753 struct perf_event_header header;
7755 } lost_samples_event = {
7757 .type = PERF_RECORD_LOST_SAMPLES,
7759 .size = sizeof(lost_samples_event),
7764 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7766 ret = perf_output_begin(&handle, event,
7767 lost_samples_event.header.size);
7771 perf_output_put(&handle, lost_samples_event);
7772 perf_event__output_id_sample(event, &handle, &sample);
7773 perf_output_end(&handle);
7777 * context_switch tracking
7780 struct perf_switch_event {
7781 struct task_struct *task;
7782 struct task_struct *next_prev;
7785 struct perf_event_header header;
7791 static int perf_event_switch_match(struct perf_event *event)
7793 return event->attr.context_switch;
7796 static void perf_event_switch_output(struct perf_event *event, void *data)
7798 struct perf_switch_event *se = data;
7799 struct perf_output_handle handle;
7800 struct perf_sample_data sample;
7803 if (!perf_event_switch_match(event))
7806 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7807 if (event->ctx->task) {
7808 se->event_id.header.type = PERF_RECORD_SWITCH;
7809 se->event_id.header.size = sizeof(se->event_id.header);
7811 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7812 se->event_id.header.size = sizeof(se->event_id);
7813 se->event_id.next_prev_pid =
7814 perf_event_pid(event, se->next_prev);
7815 se->event_id.next_prev_tid =
7816 perf_event_tid(event, se->next_prev);
7819 perf_event_header__init_id(&se->event_id.header, &sample, event);
7821 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7825 if (event->ctx->task)
7826 perf_output_put(&handle, se->event_id.header);
7828 perf_output_put(&handle, se->event_id);
7830 perf_event__output_id_sample(event, &handle, &sample);
7832 perf_output_end(&handle);
7835 static void perf_event_switch(struct task_struct *task,
7836 struct task_struct *next_prev, bool sched_in)
7838 struct perf_switch_event switch_event;
7840 /* N.B. caller checks nr_switch_events != 0 */
7842 switch_event = (struct perf_switch_event){
7844 .next_prev = next_prev,
7848 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7851 /* .next_prev_pid */
7852 /* .next_prev_tid */
7856 if (!sched_in && task->state == TASK_RUNNING)
7857 switch_event.event_id.header.misc |=
7858 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7860 perf_iterate_sb(perf_event_switch_output,
7866 * IRQ throttle logging
7869 static void perf_log_throttle(struct perf_event *event, int enable)
7871 struct perf_output_handle handle;
7872 struct perf_sample_data sample;
7876 struct perf_event_header header;
7880 } throttle_event = {
7882 .type = PERF_RECORD_THROTTLE,
7884 .size = sizeof(throttle_event),
7886 .time = perf_event_clock(event),
7887 .id = primary_event_id(event),
7888 .stream_id = event->id,
7892 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7894 perf_event_header__init_id(&throttle_event.header, &sample, event);
7896 ret = perf_output_begin(&handle, event,
7897 throttle_event.header.size);
7901 perf_output_put(&handle, throttle_event);
7902 perf_event__output_id_sample(event, &handle, &sample);
7903 perf_output_end(&handle);
7907 * ksymbol register/unregister tracking
7910 struct perf_ksymbol_event {
7914 struct perf_event_header header;
7922 static int perf_event_ksymbol_match(struct perf_event *event)
7924 return event->attr.ksymbol;
7927 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7929 struct perf_ksymbol_event *ksymbol_event = data;
7930 struct perf_output_handle handle;
7931 struct perf_sample_data sample;
7934 if (!perf_event_ksymbol_match(event))
7937 perf_event_header__init_id(&ksymbol_event->event_id.header,
7939 ret = perf_output_begin(&handle, event,
7940 ksymbol_event->event_id.header.size);
7944 perf_output_put(&handle, ksymbol_event->event_id);
7945 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7946 perf_event__output_id_sample(event, &handle, &sample);
7948 perf_output_end(&handle);
7951 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7954 struct perf_ksymbol_event ksymbol_event;
7955 char name[KSYM_NAME_LEN];
7959 if (!atomic_read(&nr_ksymbol_events))
7962 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7963 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7966 strlcpy(name, sym, KSYM_NAME_LEN);
7967 name_len = strlen(name) + 1;
7968 while (!IS_ALIGNED(name_len, sizeof(u64)))
7969 name[name_len++] = '\0';
7970 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7973 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7975 ksymbol_event = (struct perf_ksymbol_event){
7977 .name_len = name_len,
7980 .type = PERF_RECORD_KSYMBOL,
7981 .size = sizeof(ksymbol_event.event_id) +
7986 .ksym_type = ksym_type,
7991 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7994 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7998 * bpf program load/unload tracking
8001 struct perf_bpf_event {
8002 struct bpf_prog *prog;
8004 struct perf_event_header header;
8008 u8 tag[BPF_TAG_SIZE];
8012 static int perf_event_bpf_match(struct perf_event *event)
8014 return event->attr.bpf_event;
8017 static void perf_event_bpf_output(struct perf_event *event, void *data)
8019 struct perf_bpf_event *bpf_event = data;
8020 struct perf_output_handle handle;
8021 struct perf_sample_data sample;
8024 if (!perf_event_bpf_match(event))
8027 perf_event_header__init_id(&bpf_event->event_id.header,
8029 ret = perf_output_begin(&handle, event,
8030 bpf_event->event_id.header.size);
8034 perf_output_put(&handle, bpf_event->event_id);
8035 perf_event__output_id_sample(event, &handle, &sample);
8037 perf_output_end(&handle);
8040 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8041 enum perf_bpf_event_type type)
8043 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8044 char sym[KSYM_NAME_LEN];
8047 if (prog->aux->func_cnt == 0) {
8048 bpf_get_prog_name(prog, sym);
8049 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8050 (u64)(unsigned long)prog->bpf_func,
8051 prog->jited_len, unregister, sym);
8053 for (i = 0; i < prog->aux->func_cnt; i++) {
8054 struct bpf_prog *subprog = prog->aux->func[i];
8056 bpf_get_prog_name(subprog, sym);
8058 PERF_RECORD_KSYMBOL_TYPE_BPF,
8059 (u64)(unsigned long)subprog->bpf_func,
8060 subprog->jited_len, unregister, sym);
8065 void perf_event_bpf_event(struct bpf_prog *prog,
8066 enum perf_bpf_event_type type,
8069 struct perf_bpf_event bpf_event;
8071 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8072 type >= PERF_BPF_EVENT_MAX)
8076 case PERF_BPF_EVENT_PROG_LOAD:
8077 case PERF_BPF_EVENT_PROG_UNLOAD:
8078 if (atomic_read(&nr_ksymbol_events))
8079 perf_event_bpf_emit_ksymbols(prog, type);
8085 if (!atomic_read(&nr_bpf_events))
8088 bpf_event = (struct perf_bpf_event){
8092 .type = PERF_RECORD_BPF_EVENT,
8093 .size = sizeof(bpf_event.event_id),
8097 .id = prog->aux->id,
8101 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8103 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8104 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8107 void perf_event_itrace_started(struct perf_event *event)
8109 event->attach_state |= PERF_ATTACH_ITRACE;
8112 static void perf_log_itrace_start(struct perf_event *event)
8114 struct perf_output_handle handle;
8115 struct perf_sample_data sample;
8116 struct perf_aux_event {
8117 struct perf_event_header header;
8124 event = event->parent;
8126 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8127 event->attach_state & PERF_ATTACH_ITRACE)
8130 rec.header.type = PERF_RECORD_ITRACE_START;
8131 rec.header.misc = 0;
8132 rec.header.size = sizeof(rec);
8133 rec.pid = perf_event_pid(event, current);
8134 rec.tid = perf_event_tid(event, current);
8136 perf_event_header__init_id(&rec.header, &sample, event);
8137 ret = perf_output_begin(&handle, event, rec.header.size);
8142 perf_output_put(&handle, rec);
8143 perf_event__output_id_sample(event, &handle, &sample);
8145 perf_output_end(&handle);
8149 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8151 struct hw_perf_event *hwc = &event->hw;
8155 seq = __this_cpu_read(perf_throttled_seq);
8156 if (seq != hwc->interrupts_seq) {
8157 hwc->interrupts_seq = seq;
8158 hwc->interrupts = 1;
8161 if (unlikely(throttle
8162 && hwc->interrupts >= max_samples_per_tick)) {
8163 __this_cpu_inc(perf_throttled_count);
8164 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8165 hwc->interrupts = MAX_INTERRUPTS;
8166 perf_log_throttle(event, 0);
8171 if (event->attr.freq) {
8172 u64 now = perf_clock();
8173 s64 delta = now - hwc->freq_time_stamp;
8175 hwc->freq_time_stamp = now;
8177 if (delta > 0 && delta < 2*TICK_NSEC)
8178 perf_adjust_period(event, delta, hwc->last_period, true);
8184 int perf_event_account_interrupt(struct perf_event *event)
8186 return __perf_event_account_interrupt(event, 1);
8190 * Generic event overflow handling, sampling.
8193 static int __perf_event_overflow(struct perf_event *event,
8194 int throttle, struct perf_sample_data *data,
8195 struct pt_regs *regs)
8197 int events = atomic_read(&event->event_limit);
8201 * Non-sampling counters might still use the PMI to fold short
8202 * hardware counters, ignore those.
8204 if (unlikely(!is_sampling_event(event)))
8207 ret = __perf_event_account_interrupt(event, throttle);
8210 * XXX event_limit might not quite work as expected on inherited
8214 event->pending_kill = POLL_IN;
8215 if (events && atomic_dec_and_test(&event->event_limit)) {
8217 event->pending_kill = POLL_HUP;
8219 perf_event_disable_inatomic(event);
8222 READ_ONCE(event->overflow_handler)(event, data, regs);
8224 if (*perf_event_fasync(event) && event->pending_kill) {
8225 event->pending_wakeup = 1;
8226 irq_work_queue(&event->pending);
8232 int perf_event_overflow(struct perf_event *event,
8233 struct perf_sample_data *data,
8234 struct pt_regs *regs)
8236 return __perf_event_overflow(event, 1, data, regs);
8240 * Generic software event infrastructure
8243 struct swevent_htable {
8244 struct swevent_hlist *swevent_hlist;
8245 struct mutex hlist_mutex;
8248 /* Recursion avoidance in each contexts */
8249 int recursion[PERF_NR_CONTEXTS];
8252 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8255 * We directly increment event->count and keep a second value in
8256 * event->hw.period_left to count intervals. This period event
8257 * is kept in the range [-sample_period, 0] so that we can use the
8261 u64 perf_swevent_set_period(struct perf_event *event)
8263 struct hw_perf_event *hwc = &event->hw;
8264 u64 period = hwc->last_period;
8268 hwc->last_period = hwc->sample_period;
8271 old = val = local64_read(&hwc->period_left);
8275 nr = div64_u64(period + val, period);
8276 offset = nr * period;
8278 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8284 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8285 struct perf_sample_data *data,
8286 struct pt_regs *regs)
8288 struct hw_perf_event *hwc = &event->hw;
8292 overflow = perf_swevent_set_period(event);
8294 if (hwc->interrupts == MAX_INTERRUPTS)
8297 for (; overflow; overflow--) {
8298 if (__perf_event_overflow(event, throttle,
8301 * We inhibit the overflow from happening when
8302 * hwc->interrupts == MAX_INTERRUPTS.
8310 static void perf_swevent_event(struct perf_event *event, u64 nr,
8311 struct perf_sample_data *data,
8312 struct pt_regs *regs)
8314 struct hw_perf_event *hwc = &event->hw;
8316 local64_add(nr, &event->count);
8321 if (!is_sampling_event(event))
8324 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8326 return perf_swevent_overflow(event, 1, data, regs);
8328 data->period = event->hw.last_period;
8330 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8331 return perf_swevent_overflow(event, 1, data, regs);
8333 if (local64_add_negative(nr, &hwc->period_left))
8336 perf_swevent_overflow(event, 0, data, regs);
8339 static int perf_exclude_event(struct perf_event *event,
8340 struct pt_regs *regs)
8342 if (event->hw.state & PERF_HES_STOPPED)
8346 if (event->attr.exclude_user && user_mode(regs))
8349 if (event->attr.exclude_kernel && !user_mode(regs))
8356 static int perf_swevent_match(struct perf_event *event,
8357 enum perf_type_id type,
8359 struct perf_sample_data *data,
8360 struct pt_regs *regs)
8362 if (event->attr.type != type)
8365 if (event->attr.config != event_id)
8368 if (perf_exclude_event(event, regs))
8374 static inline u64 swevent_hash(u64 type, u32 event_id)
8376 u64 val = event_id | (type << 32);
8378 return hash_64(val, SWEVENT_HLIST_BITS);
8381 static inline struct hlist_head *
8382 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8384 u64 hash = swevent_hash(type, event_id);
8386 return &hlist->heads[hash];
8389 /* For the read side: events when they trigger */
8390 static inline struct hlist_head *
8391 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8393 struct swevent_hlist *hlist;
8395 hlist = rcu_dereference(swhash->swevent_hlist);
8399 return __find_swevent_head(hlist, type, event_id);
8402 /* For the event head insertion and removal in the hlist */
8403 static inline struct hlist_head *
8404 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8406 struct swevent_hlist *hlist;
8407 u32 event_id = event->attr.config;
8408 u64 type = event->attr.type;
8411 * Event scheduling is always serialized against hlist allocation
8412 * and release. Which makes the protected version suitable here.
8413 * The context lock guarantees that.
8415 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8416 lockdep_is_held(&event->ctx->lock));
8420 return __find_swevent_head(hlist, type, event_id);
8423 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8425 struct perf_sample_data *data,
8426 struct pt_regs *regs)
8428 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8429 struct perf_event *event;
8430 struct hlist_head *head;
8433 head = find_swevent_head_rcu(swhash, type, event_id);
8437 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8438 if (perf_swevent_match(event, type, event_id, data, regs))
8439 perf_swevent_event(event, nr, data, regs);
8445 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8447 int perf_swevent_get_recursion_context(void)
8449 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8451 return get_recursion_context(swhash->recursion);
8453 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8455 void perf_swevent_put_recursion_context(int rctx)
8457 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8459 put_recursion_context(swhash->recursion, rctx);
8462 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8464 struct perf_sample_data data;
8466 if (WARN_ON_ONCE(!regs))
8469 perf_sample_data_init(&data, addr, 0);
8470 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8473 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8477 preempt_disable_notrace();
8478 rctx = perf_swevent_get_recursion_context();
8479 if (unlikely(rctx < 0))
8482 ___perf_sw_event(event_id, nr, regs, addr);
8484 perf_swevent_put_recursion_context(rctx);
8486 preempt_enable_notrace();
8489 static void perf_swevent_read(struct perf_event *event)
8493 static int perf_swevent_add(struct perf_event *event, int flags)
8495 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8496 struct hw_perf_event *hwc = &event->hw;
8497 struct hlist_head *head;
8499 if (is_sampling_event(event)) {
8500 hwc->last_period = hwc->sample_period;
8501 perf_swevent_set_period(event);
8504 hwc->state = !(flags & PERF_EF_START);
8506 head = find_swevent_head(swhash, event);
8507 if (WARN_ON_ONCE(!head))
8510 hlist_add_head_rcu(&event->hlist_entry, head);
8511 perf_event_update_userpage(event);
8516 static void perf_swevent_del(struct perf_event *event, int flags)
8518 hlist_del_rcu(&event->hlist_entry);
8521 static void perf_swevent_start(struct perf_event *event, int flags)
8523 event->hw.state = 0;
8526 static void perf_swevent_stop(struct perf_event *event, int flags)
8528 event->hw.state = PERF_HES_STOPPED;
8531 /* Deref the hlist from the update side */
8532 static inline struct swevent_hlist *
8533 swevent_hlist_deref(struct swevent_htable *swhash)
8535 return rcu_dereference_protected(swhash->swevent_hlist,
8536 lockdep_is_held(&swhash->hlist_mutex));
8539 static void swevent_hlist_release(struct swevent_htable *swhash)
8541 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8546 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8547 kfree_rcu(hlist, rcu_head);
8550 static void swevent_hlist_put_cpu(int cpu)
8552 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8554 mutex_lock(&swhash->hlist_mutex);
8556 if (!--swhash->hlist_refcount)
8557 swevent_hlist_release(swhash);
8559 mutex_unlock(&swhash->hlist_mutex);
8562 static void swevent_hlist_put(void)
8566 for_each_possible_cpu(cpu)
8567 swevent_hlist_put_cpu(cpu);
8570 static int swevent_hlist_get_cpu(int cpu)
8572 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8575 mutex_lock(&swhash->hlist_mutex);
8576 if (!swevent_hlist_deref(swhash) &&
8577 cpumask_test_cpu(cpu, perf_online_mask)) {
8578 struct swevent_hlist *hlist;
8580 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8585 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8587 swhash->hlist_refcount++;
8589 mutex_unlock(&swhash->hlist_mutex);
8594 static int swevent_hlist_get(void)
8596 int err, cpu, failed_cpu;
8598 mutex_lock(&pmus_lock);
8599 for_each_possible_cpu(cpu) {
8600 err = swevent_hlist_get_cpu(cpu);
8606 mutex_unlock(&pmus_lock);
8609 for_each_possible_cpu(cpu) {
8610 if (cpu == failed_cpu)
8612 swevent_hlist_put_cpu(cpu);
8614 mutex_unlock(&pmus_lock);
8618 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8620 static void sw_perf_event_destroy(struct perf_event *event)
8622 u64 event_id = event->attr.config;
8624 WARN_ON(event->parent);
8626 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8627 swevent_hlist_put();
8630 static int perf_swevent_init(struct perf_event *event)
8632 u64 event_id = event->attr.config;
8634 if (event->attr.type != PERF_TYPE_SOFTWARE)
8638 * no branch sampling for software events
8640 if (has_branch_stack(event))
8644 case PERF_COUNT_SW_CPU_CLOCK:
8645 case PERF_COUNT_SW_TASK_CLOCK:
8652 if (event_id >= PERF_COUNT_SW_MAX)
8655 if (!event->parent) {
8658 err = swevent_hlist_get();
8662 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8663 event->destroy = sw_perf_event_destroy;
8669 static struct pmu perf_swevent = {
8670 .task_ctx_nr = perf_sw_context,
8672 .capabilities = PERF_PMU_CAP_NO_NMI,
8674 .event_init = perf_swevent_init,
8675 .add = perf_swevent_add,
8676 .del = perf_swevent_del,
8677 .start = perf_swevent_start,
8678 .stop = perf_swevent_stop,
8679 .read = perf_swevent_read,
8682 #ifdef CONFIG_EVENT_TRACING
8684 static int perf_tp_filter_match(struct perf_event *event,
8685 struct perf_sample_data *data)
8687 void *record = data->raw->frag.data;
8689 /* only top level events have filters set */
8691 event = event->parent;
8693 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8698 static int perf_tp_event_match(struct perf_event *event,
8699 struct perf_sample_data *data,
8700 struct pt_regs *regs)
8702 if (event->hw.state & PERF_HES_STOPPED)
8705 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8707 if (event->attr.exclude_kernel && !user_mode(regs))
8710 if (!perf_tp_filter_match(event, data))
8716 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8717 struct trace_event_call *call, u64 count,
8718 struct pt_regs *regs, struct hlist_head *head,
8719 struct task_struct *task)
8721 if (bpf_prog_array_valid(call)) {
8722 *(struct pt_regs **)raw_data = regs;
8723 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8724 perf_swevent_put_recursion_context(rctx);
8728 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8731 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8733 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8734 struct pt_regs *regs, struct hlist_head *head, int rctx,
8735 struct task_struct *task)
8737 struct perf_sample_data data;
8738 struct perf_event *event;
8740 struct perf_raw_record raw = {
8747 perf_sample_data_init(&data, 0, 0);
8750 perf_trace_buf_update(record, event_type);
8752 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8753 if (perf_tp_event_match(event, &data, regs))
8754 perf_swevent_event(event, count, &data, regs);
8758 * If we got specified a target task, also iterate its context and
8759 * deliver this event there too.
8761 if (task && task != current) {
8762 struct perf_event_context *ctx;
8763 struct trace_entry *entry = record;
8766 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8770 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8771 if (event->cpu != smp_processor_id())
8773 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8775 if (event->attr.config != entry->type)
8777 if (perf_tp_event_match(event, &data, regs))
8778 perf_swevent_event(event, count, &data, regs);
8784 perf_swevent_put_recursion_context(rctx);
8786 EXPORT_SYMBOL_GPL(perf_tp_event);
8788 static void tp_perf_event_destroy(struct perf_event *event)
8790 perf_trace_destroy(event);
8793 static int perf_tp_event_init(struct perf_event *event)
8797 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8801 * no branch sampling for tracepoint events
8803 if (has_branch_stack(event))
8806 err = perf_trace_init(event);
8810 event->destroy = tp_perf_event_destroy;
8815 static struct pmu perf_tracepoint = {
8816 .task_ctx_nr = perf_sw_context,
8818 .event_init = perf_tp_event_init,
8819 .add = perf_trace_add,
8820 .del = perf_trace_del,
8821 .start = perf_swevent_start,
8822 .stop = perf_swevent_stop,
8823 .read = perf_swevent_read,
8826 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8828 * Flags in config, used by dynamic PMU kprobe and uprobe
8829 * The flags should match following PMU_FORMAT_ATTR().
8831 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8832 * if not set, create kprobe/uprobe
8834 * The following values specify a reference counter (or semaphore in the
8835 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8836 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8838 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8839 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8841 enum perf_probe_config {
8842 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8843 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8844 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8847 PMU_FORMAT_ATTR(retprobe, "config:0");
8850 #ifdef CONFIG_KPROBE_EVENTS
8851 static struct attribute *kprobe_attrs[] = {
8852 &format_attr_retprobe.attr,
8856 static struct attribute_group kprobe_format_group = {
8858 .attrs = kprobe_attrs,
8861 static const struct attribute_group *kprobe_attr_groups[] = {
8862 &kprobe_format_group,
8866 static int perf_kprobe_event_init(struct perf_event *event);
8867 static struct pmu perf_kprobe = {
8868 .task_ctx_nr = perf_sw_context,
8869 .event_init = perf_kprobe_event_init,
8870 .add = perf_trace_add,
8871 .del = perf_trace_del,
8872 .start = perf_swevent_start,
8873 .stop = perf_swevent_stop,
8874 .read = perf_swevent_read,
8875 .attr_groups = kprobe_attr_groups,
8878 static int perf_kprobe_event_init(struct perf_event *event)
8883 if (event->attr.type != perf_kprobe.type)
8886 if (!capable(CAP_SYS_ADMIN))
8890 * no branch sampling for probe events
8892 if (has_branch_stack(event))
8895 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8896 err = perf_kprobe_init(event, is_retprobe);
8900 event->destroy = perf_kprobe_destroy;
8904 #endif /* CONFIG_KPROBE_EVENTS */
8906 #ifdef CONFIG_UPROBE_EVENTS
8907 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8909 static struct attribute *uprobe_attrs[] = {
8910 &format_attr_retprobe.attr,
8911 &format_attr_ref_ctr_offset.attr,
8915 static struct attribute_group uprobe_format_group = {
8917 .attrs = uprobe_attrs,
8920 static const struct attribute_group *uprobe_attr_groups[] = {
8921 &uprobe_format_group,
8925 static int perf_uprobe_event_init(struct perf_event *event);
8926 static struct pmu perf_uprobe = {
8927 .task_ctx_nr = perf_sw_context,
8928 .event_init = perf_uprobe_event_init,
8929 .add = perf_trace_add,
8930 .del = perf_trace_del,
8931 .start = perf_swevent_start,
8932 .stop = perf_swevent_stop,
8933 .read = perf_swevent_read,
8934 .attr_groups = uprobe_attr_groups,
8937 static int perf_uprobe_event_init(struct perf_event *event)
8940 unsigned long ref_ctr_offset;
8943 if (event->attr.type != perf_uprobe.type)
8946 if (!capable(CAP_SYS_ADMIN))
8950 * no branch sampling for probe events
8952 if (has_branch_stack(event))
8955 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8956 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8957 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8961 event->destroy = perf_uprobe_destroy;
8965 #endif /* CONFIG_UPROBE_EVENTS */
8967 static inline void perf_tp_register(void)
8969 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8970 #ifdef CONFIG_KPROBE_EVENTS
8971 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8973 #ifdef CONFIG_UPROBE_EVENTS
8974 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8978 static void perf_event_free_filter(struct perf_event *event)
8980 ftrace_profile_free_filter(event);
8983 #ifdef CONFIG_BPF_SYSCALL
8984 static void bpf_overflow_handler(struct perf_event *event,
8985 struct perf_sample_data *data,
8986 struct pt_regs *regs)
8988 struct bpf_perf_event_data_kern ctx = {
8994 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8996 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8999 ret = BPF_PROG_RUN(event->prog, &ctx);
9002 __this_cpu_dec(bpf_prog_active);
9007 event->orig_overflow_handler(event, data, regs);
9010 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9012 struct bpf_prog *prog;
9014 if (event->overflow_handler_context)
9015 /* hw breakpoint or kernel counter */
9021 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9023 return PTR_ERR(prog);
9026 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9027 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9031 static void perf_event_free_bpf_handler(struct perf_event *event)
9033 struct bpf_prog *prog = event->prog;
9038 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9043 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9047 static void perf_event_free_bpf_handler(struct perf_event *event)
9053 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9054 * with perf_event_open()
9056 static inline bool perf_event_is_tracing(struct perf_event *event)
9058 if (event->pmu == &perf_tracepoint)
9060 #ifdef CONFIG_KPROBE_EVENTS
9061 if (event->pmu == &perf_kprobe)
9064 #ifdef CONFIG_UPROBE_EVENTS
9065 if (event->pmu == &perf_uprobe)
9071 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9073 bool is_kprobe, is_tracepoint, is_syscall_tp;
9074 struct bpf_prog *prog;
9077 if (!perf_event_is_tracing(event))
9078 return perf_event_set_bpf_handler(event, prog_fd);
9080 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9081 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9082 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9083 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9084 /* bpf programs can only be attached to u/kprobe or tracepoint */
9087 prog = bpf_prog_get(prog_fd);
9089 return PTR_ERR(prog);
9091 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9092 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9093 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9094 /* valid fd, but invalid bpf program type */
9099 /* Kprobe override only works for kprobes, not uprobes. */
9100 if (prog->kprobe_override &&
9101 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9106 if (is_tracepoint || is_syscall_tp) {
9107 int off = trace_event_get_offsets(event->tp_event);
9109 if (prog->aux->max_ctx_offset > off) {
9115 ret = perf_event_attach_bpf_prog(event, prog);
9121 static void perf_event_free_bpf_prog(struct perf_event *event)
9123 if (!perf_event_is_tracing(event)) {
9124 perf_event_free_bpf_handler(event);
9127 perf_event_detach_bpf_prog(event);
9132 static inline void perf_tp_register(void)
9136 static void perf_event_free_filter(struct perf_event *event)
9140 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9145 static void perf_event_free_bpf_prog(struct perf_event *event)
9148 #endif /* CONFIG_EVENT_TRACING */
9150 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9151 void perf_bp_event(struct perf_event *bp, void *data)
9153 struct perf_sample_data sample;
9154 struct pt_regs *regs = data;
9156 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9158 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9159 perf_swevent_event(bp, 1, &sample, regs);
9164 * Allocate a new address filter
9166 static struct perf_addr_filter *
9167 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9169 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9170 struct perf_addr_filter *filter;
9172 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9176 INIT_LIST_HEAD(&filter->entry);
9177 list_add_tail(&filter->entry, filters);
9182 static void free_filters_list(struct list_head *filters)
9184 struct perf_addr_filter *filter, *iter;
9186 list_for_each_entry_safe(filter, iter, filters, entry) {
9187 path_put(&filter->path);
9188 list_del(&filter->entry);
9194 * Free existing address filters and optionally install new ones
9196 static void perf_addr_filters_splice(struct perf_event *event,
9197 struct list_head *head)
9199 unsigned long flags;
9202 if (!has_addr_filter(event))
9205 /* don't bother with children, they don't have their own filters */
9209 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9211 list_splice_init(&event->addr_filters.list, &list);
9213 list_splice(head, &event->addr_filters.list);
9215 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9217 free_filters_list(&list);
9221 * Scan through mm's vmas and see if one of them matches the
9222 * @filter; if so, adjust filter's address range.
9223 * Called with mm::mmap_sem down for reading.
9225 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9226 struct mm_struct *mm,
9227 struct perf_addr_filter_range *fr)
9229 struct vm_area_struct *vma;
9231 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9235 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9241 * Update event's address range filters based on the
9242 * task's existing mappings, if any.
9244 static void perf_event_addr_filters_apply(struct perf_event *event)
9246 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9247 struct task_struct *task = READ_ONCE(event->ctx->task);
9248 struct perf_addr_filter *filter;
9249 struct mm_struct *mm = NULL;
9250 unsigned int count = 0;
9251 unsigned long flags;
9254 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9255 * will stop on the parent's child_mutex that our caller is also holding
9257 if (task == TASK_TOMBSTONE)
9260 if (ifh->nr_file_filters) {
9261 mm = get_task_mm(event->ctx->task);
9265 down_read(&mm->mmap_sem);
9268 raw_spin_lock_irqsave(&ifh->lock, flags);
9269 list_for_each_entry(filter, &ifh->list, entry) {
9270 if (filter->path.dentry) {
9272 * Adjust base offset if the filter is associated to a
9273 * binary that needs to be mapped:
9275 event->addr_filter_ranges[count].start = 0;
9276 event->addr_filter_ranges[count].size = 0;
9278 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9280 event->addr_filter_ranges[count].start = filter->offset;
9281 event->addr_filter_ranges[count].size = filter->size;
9287 event->addr_filters_gen++;
9288 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9290 if (ifh->nr_file_filters) {
9291 up_read(&mm->mmap_sem);
9297 perf_event_stop(event, 1);
9301 * Address range filtering: limiting the data to certain
9302 * instruction address ranges. Filters are ioctl()ed to us from
9303 * userspace as ascii strings.
9305 * Filter string format:
9308 * where ACTION is one of the
9309 * * "filter": limit the trace to this region
9310 * * "start": start tracing from this address
9311 * * "stop": stop tracing at this address/region;
9313 * * for kernel addresses: <start address>[/<size>]
9314 * * for object files: <start address>[/<size>]@</path/to/object/file>
9316 * if <size> is not specified or is zero, the range is treated as a single
9317 * address; not valid for ACTION=="filter".
9331 IF_STATE_ACTION = 0,
9336 static const match_table_t if_tokens = {
9337 { IF_ACT_FILTER, "filter" },
9338 { IF_ACT_START, "start" },
9339 { IF_ACT_STOP, "stop" },
9340 { IF_SRC_FILE, "%u/%u@%s" },
9341 { IF_SRC_KERNEL, "%u/%u" },
9342 { IF_SRC_FILEADDR, "%u@%s" },
9343 { IF_SRC_KERNELADDR, "%u" },
9344 { IF_ACT_NONE, NULL },
9348 * Address filter string parser
9351 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9352 struct list_head *filters)
9354 struct perf_addr_filter *filter = NULL;
9355 char *start, *orig, *filename = NULL;
9356 substring_t args[MAX_OPT_ARGS];
9357 int state = IF_STATE_ACTION, token;
9358 unsigned int kernel = 0;
9361 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9365 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9366 static const enum perf_addr_filter_action_t actions[] = {
9367 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9368 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9369 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9376 /* filter definition begins */
9377 if (state == IF_STATE_ACTION) {
9378 filter = perf_addr_filter_new(event, filters);
9383 token = match_token(start, if_tokens, args);
9388 if (state != IF_STATE_ACTION)
9391 filter->action = actions[token];
9392 state = IF_STATE_SOURCE;
9395 case IF_SRC_KERNELADDR:
9400 case IF_SRC_FILEADDR:
9402 if (state != IF_STATE_SOURCE)
9406 ret = kstrtoul(args[0].from, 0, &filter->offset);
9410 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9412 ret = kstrtoul(args[1].from, 0, &filter->size);
9417 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9418 int fpos = token == IF_SRC_FILE ? 2 : 1;
9420 filename = match_strdup(&args[fpos]);
9427 state = IF_STATE_END;
9435 * Filter definition is fully parsed, validate and install it.
9436 * Make sure that it doesn't contradict itself or the event's
9439 if (state == IF_STATE_END) {
9441 if (kernel && event->attr.exclude_kernel)
9445 * ACTION "filter" must have a non-zero length region
9448 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9457 * For now, we only support file-based filters
9458 * in per-task events; doing so for CPU-wide
9459 * events requires additional context switching
9460 * trickery, since same object code will be
9461 * mapped at different virtual addresses in
9462 * different processes.
9465 if (!event->ctx->task)
9466 goto fail_free_name;
9468 /* look up the path and grab its inode */
9469 ret = kern_path(filename, LOOKUP_FOLLOW,
9472 goto fail_free_name;
9478 if (!filter->path.dentry ||
9479 !S_ISREG(d_inode(filter->path.dentry)
9483 event->addr_filters.nr_file_filters++;
9486 /* ready to consume more filters */
9487 state = IF_STATE_ACTION;
9492 if (state != IF_STATE_ACTION)
9502 free_filters_list(filters);
9509 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9515 * Since this is called in perf_ioctl() path, we're already holding
9518 lockdep_assert_held(&event->ctx->mutex);
9520 if (WARN_ON_ONCE(event->parent))
9523 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9525 goto fail_clear_files;
9527 ret = event->pmu->addr_filters_validate(&filters);
9529 goto fail_free_filters;
9531 /* remove existing filters, if any */
9532 perf_addr_filters_splice(event, &filters);
9534 /* install new filters */
9535 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9540 free_filters_list(&filters);
9543 event->addr_filters.nr_file_filters = 0;
9548 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9553 filter_str = strndup_user(arg, PAGE_SIZE);
9554 if (IS_ERR(filter_str))
9555 return PTR_ERR(filter_str);
9557 #ifdef CONFIG_EVENT_TRACING
9558 if (perf_event_is_tracing(event)) {
9559 struct perf_event_context *ctx = event->ctx;
9562 * Beware, here be dragons!!
9564 * the tracepoint muck will deadlock against ctx->mutex, but
9565 * the tracepoint stuff does not actually need it. So
9566 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9567 * already have a reference on ctx.
9569 * This can result in event getting moved to a different ctx,
9570 * but that does not affect the tracepoint state.
9572 mutex_unlock(&ctx->mutex);
9573 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9574 mutex_lock(&ctx->mutex);
9577 if (has_addr_filter(event))
9578 ret = perf_event_set_addr_filter(event, filter_str);
9585 * hrtimer based swevent callback
9588 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9590 enum hrtimer_restart ret = HRTIMER_RESTART;
9591 struct perf_sample_data data;
9592 struct pt_regs *regs;
9593 struct perf_event *event;
9596 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9598 if (event->state != PERF_EVENT_STATE_ACTIVE)
9599 return HRTIMER_NORESTART;
9601 event->pmu->read(event);
9603 perf_sample_data_init(&data, 0, event->hw.last_period);
9604 regs = get_irq_regs();
9606 if (regs && !perf_exclude_event(event, regs)) {
9607 if (!(event->attr.exclude_idle && is_idle_task(current)))
9608 if (__perf_event_overflow(event, 1, &data, regs))
9609 ret = HRTIMER_NORESTART;
9612 period = max_t(u64, 10000, event->hw.sample_period);
9613 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9618 static void perf_swevent_start_hrtimer(struct perf_event *event)
9620 struct hw_perf_event *hwc = &event->hw;
9623 if (!is_sampling_event(event))
9626 period = local64_read(&hwc->period_left);
9631 local64_set(&hwc->period_left, 0);
9633 period = max_t(u64, 10000, hwc->sample_period);
9635 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9636 HRTIMER_MODE_REL_PINNED_HARD);
9639 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9641 struct hw_perf_event *hwc = &event->hw;
9643 if (is_sampling_event(event)) {
9644 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9645 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9647 hrtimer_cancel(&hwc->hrtimer);
9651 static void perf_swevent_init_hrtimer(struct perf_event *event)
9653 struct hw_perf_event *hwc = &event->hw;
9655 if (!is_sampling_event(event))
9658 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
9659 hwc->hrtimer.function = perf_swevent_hrtimer;
9662 * Since hrtimers have a fixed rate, we can do a static freq->period
9663 * mapping and avoid the whole period adjust feedback stuff.
9665 if (event->attr.freq) {
9666 long freq = event->attr.sample_freq;
9668 event->attr.sample_period = NSEC_PER_SEC / freq;
9669 hwc->sample_period = event->attr.sample_period;
9670 local64_set(&hwc->period_left, hwc->sample_period);
9671 hwc->last_period = hwc->sample_period;
9672 event->attr.freq = 0;
9677 * Software event: cpu wall time clock
9680 static void cpu_clock_event_update(struct perf_event *event)
9685 now = local_clock();
9686 prev = local64_xchg(&event->hw.prev_count, now);
9687 local64_add(now - prev, &event->count);
9690 static void cpu_clock_event_start(struct perf_event *event, int flags)
9692 local64_set(&event->hw.prev_count, local_clock());
9693 perf_swevent_start_hrtimer(event);
9696 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9698 perf_swevent_cancel_hrtimer(event);
9699 cpu_clock_event_update(event);
9702 static int cpu_clock_event_add(struct perf_event *event, int flags)
9704 if (flags & PERF_EF_START)
9705 cpu_clock_event_start(event, flags);
9706 perf_event_update_userpage(event);
9711 static void cpu_clock_event_del(struct perf_event *event, int flags)
9713 cpu_clock_event_stop(event, flags);
9716 static void cpu_clock_event_read(struct perf_event *event)
9718 cpu_clock_event_update(event);
9721 static int cpu_clock_event_init(struct perf_event *event)
9723 if (event->attr.type != PERF_TYPE_SOFTWARE)
9726 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9730 * no branch sampling for software events
9732 if (has_branch_stack(event))
9735 perf_swevent_init_hrtimer(event);
9740 static struct pmu perf_cpu_clock = {
9741 .task_ctx_nr = perf_sw_context,
9743 .capabilities = PERF_PMU_CAP_NO_NMI,
9745 .event_init = cpu_clock_event_init,
9746 .add = cpu_clock_event_add,
9747 .del = cpu_clock_event_del,
9748 .start = cpu_clock_event_start,
9749 .stop = cpu_clock_event_stop,
9750 .read = cpu_clock_event_read,
9754 * Software event: task time clock
9757 static void task_clock_event_update(struct perf_event *event, u64 now)
9762 prev = local64_xchg(&event->hw.prev_count, now);
9764 local64_add(delta, &event->count);
9767 static void task_clock_event_start(struct perf_event *event, int flags)
9769 local64_set(&event->hw.prev_count, event->ctx->time);
9770 perf_swevent_start_hrtimer(event);
9773 static void task_clock_event_stop(struct perf_event *event, int flags)
9775 perf_swevent_cancel_hrtimer(event);
9776 task_clock_event_update(event, event->ctx->time);
9779 static int task_clock_event_add(struct perf_event *event, int flags)
9781 if (flags & PERF_EF_START)
9782 task_clock_event_start(event, flags);
9783 perf_event_update_userpage(event);
9788 static void task_clock_event_del(struct perf_event *event, int flags)
9790 task_clock_event_stop(event, PERF_EF_UPDATE);
9793 static void task_clock_event_read(struct perf_event *event)
9795 u64 now = perf_clock();
9796 u64 delta = now - event->ctx->timestamp;
9797 u64 time = event->ctx->time + delta;
9799 task_clock_event_update(event, time);
9802 static int task_clock_event_init(struct perf_event *event)
9804 if (event->attr.type != PERF_TYPE_SOFTWARE)
9807 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9811 * no branch sampling for software events
9813 if (has_branch_stack(event))
9816 perf_swevent_init_hrtimer(event);
9821 static struct pmu perf_task_clock = {
9822 .task_ctx_nr = perf_sw_context,
9824 .capabilities = PERF_PMU_CAP_NO_NMI,
9826 .event_init = task_clock_event_init,
9827 .add = task_clock_event_add,
9828 .del = task_clock_event_del,
9829 .start = task_clock_event_start,
9830 .stop = task_clock_event_stop,
9831 .read = task_clock_event_read,
9834 static void perf_pmu_nop_void(struct pmu *pmu)
9838 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9842 static int perf_pmu_nop_int(struct pmu *pmu)
9847 static int perf_event_nop_int(struct perf_event *event, u64 value)
9852 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9854 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9856 __this_cpu_write(nop_txn_flags, flags);
9858 if (flags & ~PERF_PMU_TXN_ADD)
9861 perf_pmu_disable(pmu);
9864 static int perf_pmu_commit_txn(struct pmu *pmu)
9866 unsigned int flags = __this_cpu_read(nop_txn_flags);
9868 __this_cpu_write(nop_txn_flags, 0);
9870 if (flags & ~PERF_PMU_TXN_ADD)
9873 perf_pmu_enable(pmu);
9877 static void perf_pmu_cancel_txn(struct pmu *pmu)
9879 unsigned int flags = __this_cpu_read(nop_txn_flags);
9881 __this_cpu_write(nop_txn_flags, 0);
9883 if (flags & ~PERF_PMU_TXN_ADD)
9886 perf_pmu_enable(pmu);
9889 static int perf_event_idx_default(struct perf_event *event)
9895 * Ensures all contexts with the same task_ctx_nr have the same
9896 * pmu_cpu_context too.
9898 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9905 list_for_each_entry(pmu, &pmus, entry) {
9906 if (pmu->task_ctx_nr == ctxn)
9907 return pmu->pmu_cpu_context;
9913 static void free_pmu_context(struct pmu *pmu)
9916 * Static contexts such as perf_sw_context have a global lifetime
9917 * and may be shared between different PMUs. Avoid freeing them
9918 * when a single PMU is going away.
9920 if (pmu->task_ctx_nr > perf_invalid_context)
9923 free_percpu(pmu->pmu_cpu_context);
9927 * Let userspace know that this PMU supports address range filtering:
9929 static ssize_t nr_addr_filters_show(struct device *dev,
9930 struct device_attribute *attr,
9933 struct pmu *pmu = dev_get_drvdata(dev);
9935 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9937 DEVICE_ATTR_RO(nr_addr_filters);
9939 static struct idr pmu_idr;
9942 type_show(struct device *dev, struct device_attribute *attr, char *page)
9944 struct pmu *pmu = dev_get_drvdata(dev);
9946 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9948 static DEVICE_ATTR_RO(type);
9951 perf_event_mux_interval_ms_show(struct device *dev,
9952 struct device_attribute *attr,
9955 struct pmu *pmu = dev_get_drvdata(dev);
9957 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9960 static DEFINE_MUTEX(mux_interval_mutex);
9963 perf_event_mux_interval_ms_store(struct device *dev,
9964 struct device_attribute *attr,
9965 const char *buf, size_t count)
9967 struct pmu *pmu = dev_get_drvdata(dev);
9968 int timer, cpu, ret;
9970 ret = kstrtoint(buf, 0, &timer);
9977 /* same value, noting to do */
9978 if (timer == pmu->hrtimer_interval_ms)
9981 mutex_lock(&mux_interval_mutex);
9982 pmu->hrtimer_interval_ms = timer;
9984 /* update all cpuctx for this PMU */
9986 for_each_online_cpu(cpu) {
9987 struct perf_cpu_context *cpuctx;
9988 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9989 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9991 cpu_function_call(cpu,
9992 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9995 mutex_unlock(&mux_interval_mutex);
9999 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10001 static struct attribute *pmu_dev_attrs[] = {
10002 &dev_attr_type.attr,
10003 &dev_attr_perf_event_mux_interval_ms.attr,
10006 ATTRIBUTE_GROUPS(pmu_dev);
10008 static int pmu_bus_running;
10009 static struct bus_type pmu_bus = {
10010 .name = "event_source",
10011 .dev_groups = pmu_dev_groups,
10014 static void pmu_dev_release(struct device *dev)
10019 static int pmu_dev_alloc(struct pmu *pmu)
10023 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10027 pmu->dev->groups = pmu->attr_groups;
10028 device_initialize(pmu->dev);
10029 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10033 dev_set_drvdata(pmu->dev, pmu);
10034 pmu->dev->bus = &pmu_bus;
10035 pmu->dev->release = pmu_dev_release;
10036 ret = device_add(pmu->dev);
10040 /* For PMUs with address filters, throw in an extra attribute: */
10041 if (pmu->nr_addr_filters)
10042 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10047 if (pmu->attr_update)
10048 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10057 device_del(pmu->dev);
10060 put_device(pmu->dev);
10064 static struct lock_class_key cpuctx_mutex;
10065 static struct lock_class_key cpuctx_lock;
10067 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10071 mutex_lock(&pmus_lock);
10073 pmu->pmu_disable_count = alloc_percpu(int);
10074 if (!pmu->pmu_disable_count)
10083 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
10091 if (pmu_bus_running) {
10092 ret = pmu_dev_alloc(pmu);
10098 if (pmu->task_ctx_nr == perf_hw_context) {
10099 static int hw_context_taken = 0;
10102 * Other than systems with heterogeneous CPUs, it never makes
10103 * sense for two PMUs to share perf_hw_context. PMUs which are
10104 * uncore must use perf_invalid_context.
10106 if (WARN_ON_ONCE(hw_context_taken &&
10107 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10108 pmu->task_ctx_nr = perf_invalid_context;
10110 hw_context_taken = 1;
10113 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10114 if (pmu->pmu_cpu_context)
10115 goto got_cpu_context;
10118 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10119 if (!pmu->pmu_cpu_context)
10122 for_each_possible_cpu(cpu) {
10123 struct perf_cpu_context *cpuctx;
10125 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10126 __perf_event_init_context(&cpuctx->ctx);
10127 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10128 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10129 cpuctx->ctx.pmu = pmu;
10130 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10132 __perf_mux_hrtimer_init(cpuctx, cpu);
10136 if (!pmu->start_txn) {
10137 if (pmu->pmu_enable) {
10139 * If we have pmu_enable/pmu_disable calls, install
10140 * transaction stubs that use that to try and batch
10141 * hardware accesses.
10143 pmu->start_txn = perf_pmu_start_txn;
10144 pmu->commit_txn = perf_pmu_commit_txn;
10145 pmu->cancel_txn = perf_pmu_cancel_txn;
10147 pmu->start_txn = perf_pmu_nop_txn;
10148 pmu->commit_txn = perf_pmu_nop_int;
10149 pmu->cancel_txn = perf_pmu_nop_void;
10153 if (!pmu->pmu_enable) {
10154 pmu->pmu_enable = perf_pmu_nop_void;
10155 pmu->pmu_disable = perf_pmu_nop_void;
10158 if (!pmu->check_period)
10159 pmu->check_period = perf_event_nop_int;
10161 if (!pmu->event_idx)
10162 pmu->event_idx = perf_event_idx_default;
10164 list_add_rcu(&pmu->entry, &pmus);
10165 atomic_set(&pmu->exclusive_cnt, 0);
10168 mutex_unlock(&pmus_lock);
10173 device_del(pmu->dev);
10174 put_device(pmu->dev);
10177 if (pmu->type >= PERF_TYPE_MAX)
10178 idr_remove(&pmu_idr, pmu->type);
10181 free_percpu(pmu->pmu_disable_count);
10184 EXPORT_SYMBOL_GPL(perf_pmu_register);
10186 void perf_pmu_unregister(struct pmu *pmu)
10188 mutex_lock(&pmus_lock);
10189 list_del_rcu(&pmu->entry);
10192 * We dereference the pmu list under both SRCU and regular RCU, so
10193 * synchronize against both of those.
10195 synchronize_srcu(&pmus_srcu);
10198 free_percpu(pmu->pmu_disable_count);
10199 if (pmu->type >= PERF_TYPE_MAX)
10200 idr_remove(&pmu_idr, pmu->type);
10201 if (pmu_bus_running) {
10202 if (pmu->nr_addr_filters)
10203 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10204 device_del(pmu->dev);
10205 put_device(pmu->dev);
10207 free_pmu_context(pmu);
10208 mutex_unlock(&pmus_lock);
10210 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10212 static inline bool has_extended_regs(struct perf_event *event)
10214 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10215 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10218 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10220 struct perf_event_context *ctx = NULL;
10223 if (!try_module_get(pmu->module))
10227 * A number of pmu->event_init() methods iterate the sibling_list to,
10228 * for example, validate if the group fits on the PMU. Therefore,
10229 * if this is a sibling event, acquire the ctx->mutex to protect
10230 * the sibling_list.
10232 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10234 * This ctx->mutex can nest when we're called through
10235 * inheritance. See the perf_event_ctx_lock_nested() comment.
10237 ctx = perf_event_ctx_lock_nested(event->group_leader,
10238 SINGLE_DEPTH_NESTING);
10243 ret = pmu->event_init(event);
10246 perf_event_ctx_unlock(event->group_leader, ctx);
10249 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10250 has_extended_regs(event))
10253 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10254 event_has_any_exclude_flag(event))
10257 if (ret && event->destroy)
10258 event->destroy(event);
10262 module_put(pmu->module);
10267 static struct pmu *perf_init_event(struct perf_event *event)
10273 idx = srcu_read_lock(&pmus_srcu);
10275 /* Try parent's PMU first: */
10276 if (event->parent && event->parent->pmu) {
10277 pmu = event->parent->pmu;
10278 ret = perf_try_init_event(pmu, event);
10284 pmu = idr_find(&pmu_idr, event->attr.type);
10287 ret = perf_try_init_event(pmu, event);
10289 pmu = ERR_PTR(ret);
10293 list_for_each_entry_rcu(pmu, &pmus, entry) {
10294 ret = perf_try_init_event(pmu, event);
10298 if (ret != -ENOENT) {
10299 pmu = ERR_PTR(ret);
10303 pmu = ERR_PTR(-ENOENT);
10305 srcu_read_unlock(&pmus_srcu, idx);
10310 static void attach_sb_event(struct perf_event *event)
10312 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10314 raw_spin_lock(&pel->lock);
10315 list_add_rcu(&event->sb_list, &pel->list);
10316 raw_spin_unlock(&pel->lock);
10320 * We keep a list of all !task (and therefore per-cpu) events
10321 * that need to receive side-band records.
10323 * This avoids having to scan all the various PMU per-cpu contexts
10324 * looking for them.
10326 static void account_pmu_sb_event(struct perf_event *event)
10328 if (is_sb_event(event))
10329 attach_sb_event(event);
10332 static void account_event_cpu(struct perf_event *event, int cpu)
10337 if (is_cgroup_event(event))
10338 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10341 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10342 static void account_freq_event_nohz(void)
10344 #ifdef CONFIG_NO_HZ_FULL
10345 /* Lock so we don't race with concurrent unaccount */
10346 spin_lock(&nr_freq_lock);
10347 if (atomic_inc_return(&nr_freq_events) == 1)
10348 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10349 spin_unlock(&nr_freq_lock);
10353 static void account_freq_event(void)
10355 if (tick_nohz_full_enabled())
10356 account_freq_event_nohz();
10358 atomic_inc(&nr_freq_events);
10362 static void account_event(struct perf_event *event)
10369 if (event->attach_state & PERF_ATTACH_TASK)
10371 if (event->attr.mmap || event->attr.mmap_data)
10372 atomic_inc(&nr_mmap_events);
10373 if (event->attr.comm)
10374 atomic_inc(&nr_comm_events);
10375 if (event->attr.namespaces)
10376 atomic_inc(&nr_namespaces_events);
10377 if (event->attr.task)
10378 atomic_inc(&nr_task_events);
10379 if (event->attr.freq)
10380 account_freq_event();
10381 if (event->attr.context_switch) {
10382 atomic_inc(&nr_switch_events);
10385 if (has_branch_stack(event))
10387 if (is_cgroup_event(event))
10389 if (event->attr.ksymbol)
10390 atomic_inc(&nr_ksymbol_events);
10391 if (event->attr.bpf_event)
10392 atomic_inc(&nr_bpf_events);
10396 * We need the mutex here because static_branch_enable()
10397 * must complete *before* the perf_sched_count increment
10400 if (atomic_inc_not_zero(&perf_sched_count))
10403 mutex_lock(&perf_sched_mutex);
10404 if (!atomic_read(&perf_sched_count)) {
10405 static_branch_enable(&perf_sched_events);
10407 * Guarantee that all CPUs observe they key change and
10408 * call the perf scheduling hooks before proceeding to
10409 * install events that need them.
10414 * Now that we have waited for the sync_sched(), allow further
10415 * increments to by-pass the mutex.
10417 atomic_inc(&perf_sched_count);
10418 mutex_unlock(&perf_sched_mutex);
10422 account_event_cpu(event, event->cpu);
10424 account_pmu_sb_event(event);
10428 * Allocate and initialize an event structure
10430 static struct perf_event *
10431 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10432 struct task_struct *task,
10433 struct perf_event *group_leader,
10434 struct perf_event *parent_event,
10435 perf_overflow_handler_t overflow_handler,
10436 void *context, int cgroup_fd)
10439 struct perf_event *event;
10440 struct hw_perf_event *hwc;
10441 long err = -EINVAL;
10443 if ((unsigned)cpu >= nr_cpu_ids) {
10444 if (!task || cpu != -1)
10445 return ERR_PTR(-EINVAL);
10448 event = kzalloc(sizeof(*event), GFP_KERNEL);
10450 return ERR_PTR(-ENOMEM);
10453 * Single events are their own group leaders, with an
10454 * empty sibling list:
10457 group_leader = event;
10459 mutex_init(&event->child_mutex);
10460 INIT_LIST_HEAD(&event->child_list);
10462 INIT_LIST_HEAD(&event->event_entry);
10463 INIT_LIST_HEAD(&event->sibling_list);
10464 INIT_LIST_HEAD(&event->active_list);
10465 init_event_group(event);
10466 INIT_LIST_HEAD(&event->rb_entry);
10467 INIT_LIST_HEAD(&event->active_entry);
10468 INIT_LIST_HEAD(&event->addr_filters.list);
10469 INIT_HLIST_NODE(&event->hlist_entry);
10472 init_waitqueue_head(&event->waitq);
10473 event->pending_disable = -1;
10474 init_irq_work(&event->pending, perf_pending_event);
10476 mutex_init(&event->mmap_mutex);
10477 raw_spin_lock_init(&event->addr_filters.lock);
10479 atomic_long_set(&event->refcount, 1);
10481 event->attr = *attr;
10482 event->group_leader = group_leader;
10486 event->parent = parent_event;
10488 event->ns = get_pid_ns(task_active_pid_ns(current));
10489 event->id = atomic64_inc_return(&perf_event_id);
10491 event->state = PERF_EVENT_STATE_INACTIVE;
10494 event->attach_state = PERF_ATTACH_TASK;
10496 * XXX pmu::event_init needs to know what task to account to
10497 * and we cannot use the ctx information because we need the
10498 * pmu before we get a ctx.
10500 event->hw.target = get_task_struct(task);
10503 event->clock = &local_clock;
10505 event->clock = parent_event->clock;
10507 if (!overflow_handler && parent_event) {
10508 overflow_handler = parent_event->overflow_handler;
10509 context = parent_event->overflow_handler_context;
10510 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10511 if (overflow_handler == bpf_overflow_handler) {
10512 struct bpf_prog *prog = parent_event->prog;
10514 bpf_prog_inc(prog);
10515 event->prog = prog;
10516 event->orig_overflow_handler =
10517 parent_event->orig_overflow_handler;
10522 if (overflow_handler) {
10523 event->overflow_handler = overflow_handler;
10524 event->overflow_handler_context = context;
10525 } else if (is_write_backward(event)){
10526 event->overflow_handler = perf_event_output_backward;
10527 event->overflow_handler_context = NULL;
10529 event->overflow_handler = perf_event_output_forward;
10530 event->overflow_handler_context = NULL;
10533 perf_event__state_init(event);
10538 hwc->sample_period = attr->sample_period;
10539 if (attr->freq && attr->sample_freq)
10540 hwc->sample_period = 1;
10541 hwc->last_period = hwc->sample_period;
10543 local64_set(&hwc->period_left, hwc->sample_period);
10546 * We currently do not support PERF_SAMPLE_READ on inherited events.
10547 * See perf_output_read().
10549 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10552 if (!has_branch_stack(event))
10553 event->attr.branch_sample_type = 0;
10555 if (cgroup_fd != -1) {
10556 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10561 pmu = perf_init_event(event);
10563 err = PTR_ERR(pmu);
10568 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
10569 * be different on other CPUs in the uncore mask.
10571 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
10576 if (event->attr.aux_output &&
10577 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10582 err = exclusive_event_init(event);
10586 if (has_addr_filter(event)) {
10587 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10588 sizeof(struct perf_addr_filter_range),
10590 if (!event->addr_filter_ranges) {
10596 * Clone the parent's vma offsets: they are valid until exec()
10597 * even if the mm is not shared with the parent.
10599 if (event->parent) {
10600 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10602 raw_spin_lock_irq(&ifh->lock);
10603 memcpy(event->addr_filter_ranges,
10604 event->parent->addr_filter_ranges,
10605 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10606 raw_spin_unlock_irq(&ifh->lock);
10609 /* force hw sync on the address filters */
10610 event->addr_filters_gen = 1;
10613 if (!event->parent) {
10614 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10615 err = get_callchain_buffers(attr->sample_max_stack);
10617 goto err_addr_filters;
10621 /* symmetric to unaccount_event() in _free_event() */
10622 account_event(event);
10627 kfree(event->addr_filter_ranges);
10630 exclusive_event_destroy(event);
10633 if (event->destroy)
10634 event->destroy(event);
10635 module_put(pmu->module);
10637 if (is_cgroup_event(event))
10638 perf_detach_cgroup(event);
10640 put_pid_ns(event->ns);
10641 if (event->hw.target)
10642 put_task_struct(event->hw.target);
10645 return ERR_PTR(err);
10648 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10649 struct perf_event_attr *attr)
10654 /* Zero the full structure, so that a short copy will be nice. */
10655 memset(attr, 0, sizeof(*attr));
10657 ret = get_user(size, &uattr->size);
10661 /* ABI compatibility quirk: */
10663 size = PERF_ATTR_SIZE_VER0;
10664 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
10667 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
10676 if (attr->__reserved_1 || attr->__reserved_2)
10679 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10682 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10685 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10686 u64 mask = attr->branch_sample_type;
10688 /* only using defined bits */
10689 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10692 /* at least one branch bit must be set */
10693 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10696 /* propagate priv level, when not set for branch */
10697 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10699 /* exclude_kernel checked on syscall entry */
10700 if (!attr->exclude_kernel)
10701 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10703 if (!attr->exclude_user)
10704 mask |= PERF_SAMPLE_BRANCH_USER;
10706 if (!attr->exclude_hv)
10707 mask |= PERF_SAMPLE_BRANCH_HV;
10709 * adjust user setting (for HW filter setup)
10711 attr->branch_sample_type = mask;
10713 /* privileged levels capture (kernel, hv): check permissions */
10714 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10715 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10719 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10720 ret = perf_reg_validate(attr->sample_regs_user);
10725 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10726 if (!arch_perf_have_user_stack_dump())
10730 * We have __u32 type for the size, but so far
10731 * we can only use __u16 as maximum due to the
10732 * __u16 sample size limit.
10734 if (attr->sample_stack_user >= USHRT_MAX)
10736 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10740 if (!attr->sample_max_stack)
10741 attr->sample_max_stack = sysctl_perf_event_max_stack;
10743 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10744 ret = perf_reg_validate(attr->sample_regs_intr);
10749 put_user(sizeof(*attr), &uattr->size);
10755 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10757 struct ring_buffer *rb = NULL;
10763 /* don't allow circular references */
10764 if (event == output_event)
10768 * Don't allow cross-cpu buffers
10770 if (output_event->cpu != event->cpu)
10774 * If its not a per-cpu rb, it must be the same task.
10776 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10780 * Mixing clocks in the same buffer is trouble you don't need.
10782 if (output_event->clock != event->clock)
10786 * Either writing ring buffer from beginning or from end.
10787 * Mixing is not allowed.
10789 if (is_write_backward(output_event) != is_write_backward(event))
10793 * If both events generate aux data, they must be on the same PMU
10795 if (has_aux(event) && has_aux(output_event) &&
10796 event->pmu != output_event->pmu)
10800 mutex_lock(&event->mmap_mutex);
10801 /* Can't redirect output if we've got an active mmap() */
10802 if (atomic_read(&event->mmap_count))
10805 if (output_event) {
10806 /* get the rb we want to redirect to */
10807 rb = ring_buffer_get(output_event);
10812 ring_buffer_attach(event, rb);
10816 mutex_unlock(&event->mmap_mutex);
10822 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10828 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10831 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10833 bool nmi_safe = false;
10836 case CLOCK_MONOTONIC:
10837 event->clock = &ktime_get_mono_fast_ns;
10841 case CLOCK_MONOTONIC_RAW:
10842 event->clock = &ktime_get_raw_fast_ns;
10846 case CLOCK_REALTIME:
10847 event->clock = &ktime_get_real_ns;
10850 case CLOCK_BOOTTIME:
10851 event->clock = &ktime_get_boottime_ns;
10855 event->clock = &ktime_get_clocktai_ns;
10862 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10869 * Variation on perf_event_ctx_lock_nested(), except we take two context
10872 static struct perf_event_context *
10873 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10874 struct perf_event_context *ctx)
10876 struct perf_event_context *gctx;
10880 gctx = READ_ONCE(group_leader->ctx);
10881 if (!refcount_inc_not_zero(&gctx->refcount)) {
10887 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10889 if (group_leader->ctx != gctx) {
10890 mutex_unlock(&ctx->mutex);
10891 mutex_unlock(&gctx->mutex);
10900 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10902 * @attr_uptr: event_id type attributes for monitoring/sampling
10905 * @group_fd: group leader event fd
10907 SYSCALL_DEFINE5(perf_event_open,
10908 struct perf_event_attr __user *, attr_uptr,
10909 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10911 struct perf_event *group_leader = NULL, *output_event = NULL;
10912 struct perf_event *event, *sibling;
10913 struct perf_event_attr attr;
10914 struct perf_event_context *ctx, *uninitialized_var(gctx);
10915 struct file *event_file = NULL;
10916 struct fd group = {NULL, 0};
10917 struct task_struct *task = NULL;
10920 int move_group = 0;
10922 int f_flags = O_RDWR;
10923 int cgroup_fd = -1;
10925 /* for future expandability... */
10926 if (flags & ~PERF_FLAG_ALL)
10929 err = perf_copy_attr(attr_uptr, &attr);
10933 if (!attr.exclude_kernel) {
10934 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10938 if (attr.namespaces) {
10939 if (!capable(CAP_SYS_ADMIN))
10944 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10947 if (attr.sample_period & (1ULL << 63))
10951 /* Only privileged users can get physical addresses */
10952 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10953 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10956 err = security_locked_down(LOCKDOWN_PERF);
10957 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
10958 /* REGS_INTR can leak data, lockdown must prevent this */
10964 * In cgroup mode, the pid argument is used to pass the fd
10965 * opened to the cgroup directory in cgroupfs. The cpu argument
10966 * designates the cpu on which to monitor threads from that
10969 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10972 if (flags & PERF_FLAG_FD_CLOEXEC)
10973 f_flags |= O_CLOEXEC;
10975 event_fd = get_unused_fd_flags(f_flags);
10979 if (group_fd != -1) {
10980 err = perf_fget_light(group_fd, &group);
10983 group_leader = group.file->private_data;
10984 if (flags & PERF_FLAG_FD_OUTPUT)
10985 output_event = group_leader;
10986 if (flags & PERF_FLAG_FD_NO_GROUP)
10987 group_leader = NULL;
10990 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10991 task = find_lively_task_by_vpid(pid);
10992 if (IS_ERR(task)) {
10993 err = PTR_ERR(task);
10998 if (task && group_leader &&
10999 group_leader->attr.inherit != attr.inherit) {
11005 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
11010 * Reuse ptrace permission checks for now.
11012 * We must hold cred_guard_mutex across this and any potential
11013 * perf_install_in_context() call for this new event to
11014 * serialize against exec() altering our credentials (and the
11015 * perf_event_exit_task() that could imply).
11018 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
11022 if (flags & PERF_FLAG_PID_CGROUP)
11025 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11026 NULL, NULL, cgroup_fd);
11027 if (IS_ERR(event)) {
11028 err = PTR_ERR(event);
11032 if (is_sampling_event(event)) {
11033 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11040 * Special case software events and allow them to be part of
11041 * any hardware group.
11045 if (attr.use_clockid) {
11046 err = perf_event_set_clock(event, attr.clockid);
11051 if (pmu->task_ctx_nr == perf_sw_context)
11052 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11054 if (group_leader) {
11055 if (is_software_event(event) &&
11056 !in_software_context(group_leader)) {
11058 * If the event is a sw event, but the group_leader
11059 * is on hw context.
11061 * Allow the addition of software events to hw
11062 * groups, this is safe because software events
11063 * never fail to schedule.
11065 pmu = group_leader->ctx->pmu;
11066 } else if (!is_software_event(event) &&
11067 is_software_event(group_leader) &&
11068 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11070 * In case the group is a pure software group, and we
11071 * try to add a hardware event, move the whole group to
11072 * the hardware context.
11079 * Get the target context (task or percpu):
11081 ctx = find_get_context(pmu, task, event);
11083 err = PTR_ERR(ctx);
11088 * Look up the group leader (we will attach this event to it):
11090 if (group_leader) {
11094 * Do not allow a recursive hierarchy (this new sibling
11095 * becoming part of another group-sibling):
11097 if (group_leader->group_leader != group_leader)
11100 /* All events in a group should have the same clock */
11101 if (group_leader->clock != event->clock)
11105 * Make sure we're both events for the same CPU;
11106 * grouping events for different CPUs is broken; since
11107 * you can never concurrently schedule them anyhow.
11109 if (group_leader->cpu != event->cpu)
11113 * Make sure we're both on the same task, or both
11116 if (group_leader->ctx->task != ctx->task)
11120 * Do not allow to attach to a group in a different task
11121 * or CPU context. If we're moving SW events, we'll fix
11122 * this up later, so allow that.
11124 if (!move_group && group_leader->ctx != ctx)
11128 * Only a group leader can be exclusive or pinned
11130 if (attr.exclusive || attr.pinned)
11134 if (output_event) {
11135 err = perf_event_set_output(event, output_event);
11140 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11142 if (IS_ERR(event_file)) {
11143 err = PTR_ERR(event_file);
11149 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11151 if (gctx->task == TASK_TOMBSTONE) {
11157 * Check if we raced against another sys_perf_event_open() call
11158 * moving the software group underneath us.
11160 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11162 * If someone moved the group out from under us, check
11163 * if this new event wound up on the same ctx, if so
11164 * its the regular !move_group case, otherwise fail.
11170 perf_event_ctx_unlock(group_leader, gctx);
11176 * Failure to create exclusive events returns -EBUSY.
11179 if (!exclusive_event_installable(group_leader, ctx))
11182 for_each_sibling_event(sibling, group_leader) {
11183 if (!exclusive_event_installable(sibling, ctx))
11187 mutex_lock(&ctx->mutex);
11190 if (ctx->task == TASK_TOMBSTONE) {
11195 if (!perf_event_validate_size(event)) {
11202 * Check if the @cpu we're creating an event for is online.
11204 * We use the perf_cpu_context::ctx::mutex to serialize against
11205 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11207 struct perf_cpu_context *cpuctx =
11208 container_of(ctx, struct perf_cpu_context, ctx);
11210 if (!cpuctx->online) {
11216 if (event->attr.aux_output && !perf_get_aux_event(event, group_leader))
11220 * Must be under the same ctx::mutex as perf_install_in_context(),
11221 * because we need to serialize with concurrent event creation.
11223 if (!exclusive_event_installable(event, ctx)) {
11228 WARN_ON_ONCE(ctx->parent_ctx);
11231 * This is the point on no return; we cannot fail hereafter. This is
11232 * where we start modifying current state.
11237 * See perf_event_ctx_lock() for comments on the details
11238 * of swizzling perf_event::ctx.
11240 perf_remove_from_context(group_leader, 0);
11243 for_each_sibling_event(sibling, group_leader) {
11244 perf_remove_from_context(sibling, 0);
11249 * Wait for everybody to stop referencing the events through
11250 * the old lists, before installing it on new lists.
11255 * Install the group siblings before the group leader.
11257 * Because a group leader will try and install the entire group
11258 * (through the sibling list, which is still in-tact), we can
11259 * end up with siblings installed in the wrong context.
11261 * By installing siblings first we NO-OP because they're not
11262 * reachable through the group lists.
11264 for_each_sibling_event(sibling, group_leader) {
11265 perf_event__state_init(sibling);
11266 perf_install_in_context(ctx, sibling, sibling->cpu);
11271 * Removing from the context ends up with disabled
11272 * event. What we want here is event in the initial
11273 * startup state, ready to be add into new context.
11275 perf_event__state_init(group_leader);
11276 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11281 * Precalculate sample_data sizes; do while holding ctx::mutex such
11282 * that we're serialized against further additions and before
11283 * perf_install_in_context() which is the point the event is active and
11284 * can use these values.
11286 perf_event__header_size(event);
11287 perf_event__id_header_size(event);
11289 event->owner = current;
11291 perf_install_in_context(ctx, event, event->cpu);
11292 perf_unpin_context(ctx);
11295 perf_event_ctx_unlock(group_leader, gctx);
11296 mutex_unlock(&ctx->mutex);
11299 mutex_unlock(&task->signal->cred_guard_mutex);
11300 put_task_struct(task);
11303 mutex_lock(¤t->perf_event_mutex);
11304 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11305 mutex_unlock(¤t->perf_event_mutex);
11308 * Drop the reference on the group_event after placing the
11309 * new event on the sibling_list. This ensures destruction
11310 * of the group leader will find the pointer to itself in
11311 * perf_group_detach().
11314 fd_install(event_fd, event_file);
11319 perf_event_ctx_unlock(group_leader, gctx);
11320 mutex_unlock(&ctx->mutex);
11324 perf_unpin_context(ctx);
11328 * If event_file is set, the fput() above will have called ->release()
11329 * and that will take care of freeing the event.
11335 mutex_unlock(&task->signal->cred_guard_mutex);
11338 put_task_struct(task);
11342 put_unused_fd(event_fd);
11347 * perf_event_create_kernel_counter
11349 * @attr: attributes of the counter to create
11350 * @cpu: cpu in which the counter is bound
11351 * @task: task to profile (NULL for percpu)
11353 struct perf_event *
11354 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11355 struct task_struct *task,
11356 perf_overflow_handler_t overflow_handler,
11359 struct perf_event_context *ctx;
11360 struct perf_event *event;
11364 * Grouping is not supported for kernel events, neither is 'AUX',
11365 * make sure the caller's intentions are adjusted.
11367 if (attr->aux_output)
11368 return ERR_PTR(-EINVAL);
11370 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11371 overflow_handler, context, -1);
11372 if (IS_ERR(event)) {
11373 err = PTR_ERR(event);
11377 /* Mark owner so we could distinguish it from user events. */
11378 event->owner = TASK_TOMBSTONE;
11381 * Get the target context (task or percpu):
11383 ctx = find_get_context(event->pmu, task, event);
11385 err = PTR_ERR(ctx);
11389 WARN_ON_ONCE(ctx->parent_ctx);
11390 mutex_lock(&ctx->mutex);
11391 if (ctx->task == TASK_TOMBSTONE) {
11398 * Check if the @cpu we're creating an event for is online.
11400 * We use the perf_cpu_context::ctx::mutex to serialize against
11401 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11403 struct perf_cpu_context *cpuctx =
11404 container_of(ctx, struct perf_cpu_context, ctx);
11405 if (!cpuctx->online) {
11411 if (!exclusive_event_installable(event, ctx)) {
11416 perf_install_in_context(ctx, event, event->cpu);
11417 perf_unpin_context(ctx);
11418 mutex_unlock(&ctx->mutex);
11423 mutex_unlock(&ctx->mutex);
11424 perf_unpin_context(ctx);
11429 return ERR_PTR(err);
11431 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11433 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11435 struct perf_event_context *src_ctx;
11436 struct perf_event_context *dst_ctx;
11437 struct perf_event *event, *tmp;
11440 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11441 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11444 * See perf_event_ctx_lock() for comments on the details
11445 * of swizzling perf_event::ctx.
11447 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11448 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11450 perf_remove_from_context(event, 0);
11451 unaccount_event_cpu(event, src_cpu);
11453 list_add(&event->migrate_entry, &events);
11457 * Wait for the events to quiesce before re-instating them.
11462 * Re-instate events in 2 passes.
11464 * Skip over group leaders and only install siblings on this first
11465 * pass, siblings will not get enabled without a leader, however a
11466 * leader will enable its siblings, even if those are still on the old
11469 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11470 if (event->group_leader == event)
11473 list_del(&event->migrate_entry);
11474 if (event->state >= PERF_EVENT_STATE_OFF)
11475 event->state = PERF_EVENT_STATE_INACTIVE;
11476 account_event_cpu(event, dst_cpu);
11477 perf_install_in_context(dst_ctx, event, dst_cpu);
11482 * Once all the siblings are setup properly, install the group leaders
11485 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11486 list_del(&event->migrate_entry);
11487 if (event->state >= PERF_EVENT_STATE_OFF)
11488 event->state = PERF_EVENT_STATE_INACTIVE;
11489 account_event_cpu(event, dst_cpu);
11490 perf_install_in_context(dst_ctx, event, dst_cpu);
11493 mutex_unlock(&dst_ctx->mutex);
11494 mutex_unlock(&src_ctx->mutex);
11496 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11498 static void sync_child_event(struct perf_event *child_event,
11499 struct task_struct *child)
11501 struct perf_event *parent_event = child_event->parent;
11504 if (child_event->attr.inherit_stat)
11505 perf_event_read_event(child_event, child);
11507 child_val = perf_event_count(child_event);
11510 * Add back the child's count to the parent's count:
11512 atomic64_add(child_val, &parent_event->child_count);
11513 atomic64_add(child_event->total_time_enabled,
11514 &parent_event->child_total_time_enabled);
11515 atomic64_add(child_event->total_time_running,
11516 &parent_event->child_total_time_running);
11520 perf_event_exit_event(struct perf_event *child_event,
11521 struct perf_event_context *child_ctx,
11522 struct task_struct *child)
11524 struct perf_event *parent_event = child_event->parent;
11527 * Do not destroy the 'original' grouping; because of the context
11528 * switch optimization the original events could've ended up in a
11529 * random child task.
11531 * If we were to destroy the original group, all group related
11532 * operations would cease to function properly after this random
11535 * Do destroy all inherited groups, we don't care about those
11536 * and being thorough is better.
11538 raw_spin_lock_irq(&child_ctx->lock);
11539 WARN_ON_ONCE(child_ctx->is_active);
11542 perf_group_detach(child_event);
11543 list_del_event(child_event, child_ctx);
11544 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11545 raw_spin_unlock_irq(&child_ctx->lock);
11548 * Parent events are governed by their filedesc, retain them.
11550 if (!parent_event) {
11551 perf_event_wakeup(child_event);
11555 * Child events can be cleaned up.
11558 sync_child_event(child_event, child);
11561 * Remove this event from the parent's list
11563 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11564 mutex_lock(&parent_event->child_mutex);
11565 list_del_init(&child_event->child_list);
11566 mutex_unlock(&parent_event->child_mutex);
11569 * Kick perf_poll() for is_event_hup().
11571 perf_event_wakeup(parent_event);
11572 free_event(child_event);
11573 put_event(parent_event);
11576 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11578 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11579 struct perf_event *child_event, *next;
11581 WARN_ON_ONCE(child != current);
11583 child_ctx = perf_pin_task_context(child, ctxn);
11588 * In order to reduce the amount of tricky in ctx tear-down, we hold
11589 * ctx::mutex over the entire thing. This serializes against almost
11590 * everything that wants to access the ctx.
11592 * The exception is sys_perf_event_open() /
11593 * perf_event_create_kernel_count() which does find_get_context()
11594 * without ctx::mutex (it cannot because of the move_group double mutex
11595 * lock thing). See the comments in perf_install_in_context().
11597 mutex_lock(&child_ctx->mutex);
11600 * In a single ctx::lock section, de-schedule the events and detach the
11601 * context from the task such that we cannot ever get it scheduled back
11604 raw_spin_lock_irq(&child_ctx->lock);
11605 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11608 * Now that the context is inactive, destroy the task <-> ctx relation
11609 * and mark the context dead.
11611 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11612 put_ctx(child_ctx); /* cannot be last */
11613 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11614 put_task_struct(current); /* cannot be last */
11616 clone_ctx = unclone_ctx(child_ctx);
11617 raw_spin_unlock_irq(&child_ctx->lock);
11620 put_ctx(clone_ctx);
11623 * Report the task dead after unscheduling the events so that we
11624 * won't get any samples after PERF_RECORD_EXIT. We can however still
11625 * get a few PERF_RECORD_READ events.
11627 perf_event_task(child, child_ctx, 0);
11629 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11630 perf_event_exit_event(child_event, child_ctx, child);
11632 mutex_unlock(&child_ctx->mutex);
11634 put_ctx(child_ctx);
11638 * When a child task exits, feed back event values to parent events.
11640 * Can be called with cred_guard_mutex held when called from
11641 * install_exec_creds().
11643 void perf_event_exit_task(struct task_struct *child)
11645 struct perf_event *event, *tmp;
11648 mutex_lock(&child->perf_event_mutex);
11649 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11651 list_del_init(&event->owner_entry);
11654 * Ensure the list deletion is visible before we clear
11655 * the owner, closes a race against perf_release() where
11656 * we need to serialize on the owner->perf_event_mutex.
11658 smp_store_release(&event->owner, NULL);
11660 mutex_unlock(&child->perf_event_mutex);
11662 for_each_task_context_nr(ctxn)
11663 perf_event_exit_task_context(child, ctxn);
11666 * The perf_event_exit_task_context calls perf_event_task
11667 * with child's task_ctx, which generates EXIT events for
11668 * child contexts and sets child->perf_event_ctxp[] to NULL.
11669 * At this point we need to send EXIT events to cpu contexts.
11671 perf_event_task(child, NULL, 0);
11674 static void perf_free_event(struct perf_event *event,
11675 struct perf_event_context *ctx)
11677 struct perf_event *parent = event->parent;
11679 if (WARN_ON_ONCE(!parent))
11682 mutex_lock(&parent->child_mutex);
11683 list_del_init(&event->child_list);
11684 mutex_unlock(&parent->child_mutex);
11688 raw_spin_lock_irq(&ctx->lock);
11689 perf_group_detach(event);
11690 list_del_event(event, ctx);
11691 raw_spin_unlock_irq(&ctx->lock);
11696 * Free a context as created by inheritance by perf_event_init_task() below,
11697 * used by fork() in case of fail.
11699 * Even though the task has never lived, the context and events have been
11700 * exposed through the child_list, so we must take care tearing it all down.
11702 void perf_event_free_task(struct task_struct *task)
11704 struct perf_event_context *ctx;
11705 struct perf_event *event, *tmp;
11708 for_each_task_context_nr(ctxn) {
11709 ctx = task->perf_event_ctxp[ctxn];
11713 mutex_lock(&ctx->mutex);
11714 raw_spin_lock_irq(&ctx->lock);
11716 * Destroy the task <-> ctx relation and mark the context dead.
11718 * This is important because even though the task hasn't been
11719 * exposed yet the context has been (through child_list).
11721 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11722 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11723 put_task_struct(task); /* cannot be last */
11724 raw_spin_unlock_irq(&ctx->lock);
11726 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11727 perf_free_event(event, ctx);
11729 mutex_unlock(&ctx->mutex);
11732 * perf_event_release_kernel() could've stolen some of our
11733 * child events and still have them on its free_list. In that
11734 * case we must wait for these events to have been freed (in
11735 * particular all their references to this task must've been
11738 * Without this copy_process() will unconditionally free this
11739 * task (irrespective of its reference count) and
11740 * _free_event()'s put_task_struct(event->hw.target) will be a
11743 * Wait for all events to drop their context reference.
11745 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
11746 put_ctx(ctx); /* must be last */
11750 void perf_event_delayed_put(struct task_struct *task)
11754 for_each_task_context_nr(ctxn)
11755 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11758 struct file *perf_event_get(unsigned int fd)
11760 struct file *file = fget(fd);
11762 return ERR_PTR(-EBADF);
11764 if (file->f_op != &perf_fops) {
11766 return ERR_PTR(-EBADF);
11772 const struct perf_event *perf_get_event(struct file *file)
11774 if (file->f_op != &perf_fops)
11775 return ERR_PTR(-EINVAL);
11777 return file->private_data;
11780 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11783 return ERR_PTR(-EINVAL);
11785 return &event->attr;
11789 * Inherit an event from parent task to child task.
11792 * - valid pointer on success
11793 * - NULL for orphaned events
11794 * - IS_ERR() on error
11796 static struct perf_event *
11797 inherit_event(struct perf_event *parent_event,
11798 struct task_struct *parent,
11799 struct perf_event_context *parent_ctx,
11800 struct task_struct *child,
11801 struct perf_event *group_leader,
11802 struct perf_event_context *child_ctx)
11804 enum perf_event_state parent_state = parent_event->state;
11805 struct perf_event *child_event;
11806 unsigned long flags;
11809 * Instead of creating recursive hierarchies of events,
11810 * we link inherited events back to the original parent,
11811 * which has a filp for sure, which we use as the reference
11814 if (parent_event->parent)
11815 parent_event = parent_event->parent;
11817 child_event = perf_event_alloc(&parent_event->attr,
11820 group_leader, parent_event,
11822 if (IS_ERR(child_event))
11823 return child_event;
11826 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11827 !child_ctx->task_ctx_data) {
11828 struct pmu *pmu = child_event->pmu;
11830 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11832 if (!child_ctx->task_ctx_data) {
11833 free_event(child_event);
11834 return ERR_PTR(-ENOMEM);
11839 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11840 * must be under the same lock in order to serialize against
11841 * perf_event_release_kernel(), such that either we must observe
11842 * is_orphaned_event() or they will observe us on the child_list.
11844 mutex_lock(&parent_event->child_mutex);
11845 if (is_orphaned_event(parent_event) ||
11846 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11847 mutex_unlock(&parent_event->child_mutex);
11848 /* task_ctx_data is freed with child_ctx */
11849 free_event(child_event);
11853 get_ctx(child_ctx);
11856 * Make the child state follow the state of the parent event,
11857 * not its attr.disabled bit. We hold the parent's mutex,
11858 * so we won't race with perf_event_{en, dis}able_family.
11860 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11861 child_event->state = PERF_EVENT_STATE_INACTIVE;
11863 child_event->state = PERF_EVENT_STATE_OFF;
11865 if (parent_event->attr.freq) {
11866 u64 sample_period = parent_event->hw.sample_period;
11867 struct hw_perf_event *hwc = &child_event->hw;
11869 hwc->sample_period = sample_period;
11870 hwc->last_period = sample_period;
11872 local64_set(&hwc->period_left, sample_period);
11875 child_event->ctx = child_ctx;
11876 child_event->overflow_handler = parent_event->overflow_handler;
11877 child_event->overflow_handler_context
11878 = parent_event->overflow_handler_context;
11881 * Precalculate sample_data sizes
11883 perf_event__header_size(child_event);
11884 perf_event__id_header_size(child_event);
11887 * Link it up in the child's context:
11889 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11890 add_event_to_ctx(child_event, child_ctx);
11891 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11894 * Link this into the parent event's child list
11896 list_add_tail(&child_event->child_list, &parent_event->child_list);
11897 mutex_unlock(&parent_event->child_mutex);
11899 return child_event;
11903 * Inherits an event group.
11905 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11906 * This matches with perf_event_release_kernel() removing all child events.
11912 static int inherit_group(struct perf_event *parent_event,
11913 struct task_struct *parent,
11914 struct perf_event_context *parent_ctx,
11915 struct task_struct *child,
11916 struct perf_event_context *child_ctx)
11918 struct perf_event *leader;
11919 struct perf_event *sub;
11920 struct perf_event *child_ctr;
11922 leader = inherit_event(parent_event, parent, parent_ctx,
11923 child, NULL, child_ctx);
11924 if (IS_ERR(leader))
11925 return PTR_ERR(leader);
11927 * @leader can be NULL here because of is_orphaned_event(). In this
11928 * case inherit_event() will create individual events, similar to what
11929 * perf_group_detach() would do anyway.
11931 for_each_sibling_event(sub, parent_event) {
11932 child_ctr = inherit_event(sub, parent, parent_ctx,
11933 child, leader, child_ctx);
11934 if (IS_ERR(child_ctr))
11935 return PTR_ERR(child_ctr);
11937 if (sub->aux_event == parent_event && child_ctr &&
11938 !perf_get_aux_event(child_ctr, leader))
11945 * Creates the child task context and tries to inherit the event-group.
11947 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11948 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11949 * consistent with perf_event_release_kernel() removing all child events.
11956 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11957 struct perf_event_context *parent_ctx,
11958 struct task_struct *child, int ctxn,
11959 int *inherited_all)
11962 struct perf_event_context *child_ctx;
11964 if (!event->attr.inherit) {
11965 *inherited_all = 0;
11969 child_ctx = child->perf_event_ctxp[ctxn];
11972 * This is executed from the parent task context, so
11973 * inherit events that have been marked for cloning.
11974 * First allocate and initialize a context for the
11977 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11981 child->perf_event_ctxp[ctxn] = child_ctx;
11984 ret = inherit_group(event, parent, parent_ctx,
11988 *inherited_all = 0;
11994 * Initialize the perf_event context in task_struct
11996 static int perf_event_init_context(struct task_struct *child, int ctxn)
11998 struct perf_event_context *child_ctx, *parent_ctx;
11999 struct perf_event_context *cloned_ctx;
12000 struct perf_event *event;
12001 struct task_struct *parent = current;
12002 int inherited_all = 1;
12003 unsigned long flags;
12006 if (likely(!parent->perf_event_ctxp[ctxn]))
12010 * If the parent's context is a clone, pin it so it won't get
12011 * swapped under us.
12013 parent_ctx = perf_pin_task_context(parent, ctxn);
12018 * No need to check if parent_ctx != NULL here; since we saw
12019 * it non-NULL earlier, the only reason for it to become NULL
12020 * is if we exit, and since we're currently in the middle of
12021 * a fork we can't be exiting at the same time.
12025 * Lock the parent list. No need to lock the child - not PID
12026 * hashed yet and not running, so nobody can access it.
12028 mutex_lock(&parent_ctx->mutex);
12031 * We dont have to disable NMIs - we are only looking at
12032 * the list, not manipulating it:
12034 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12035 ret = inherit_task_group(event, parent, parent_ctx,
12036 child, ctxn, &inherited_all);
12042 * We can't hold ctx->lock when iterating the ->flexible_group list due
12043 * to allocations, but we need to prevent rotation because
12044 * rotate_ctx() will change the list from interrupt context.
12046 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12047 parent_ctx->rotate_disable = 1;
12048 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12050 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12051 ret = inherit_task_group(event, parent, parent_ctx,
12052 child, ctxn, &inherited_all);
12057 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12058 parent_ctx->rotate_disable = 0;
12060 child_ctx = child->perf_event_ctxp[ctxn];
12062 if (child_ctx && inherited_all) {
12064 * Mark the child context as a clone of the parent
12065 * context, or of whatever the parent is a clone of.
12067 * Note that if the parent is a clone, the holding of
12068 * parent_ctx->lock avoids it from being uncloned.
12070 cloned_ctx = parent_ctx->parent_ctx;
12072 child_ctx->parent_ctx = cloned_ctx;
12073 child_ctx->parent_gen = parent_ctx->parent_gen;
12075 child_ctx->parent_ctx = parent_ctx;
12076 child_ctx->parent_gen = parent_ctx->generation;
12078 get_ctx(child_ctx->parent_ctx);
12081 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12083 mutex_unlock(&parent_ctx->mutex);
12085 perf_unpin_context(parent_ctx);
12086 put_ctx(parent_ctx);
12092 * Initialize the perf_event context in task_struct
12094 int perf_event_init_task(struct task_struct *child)
12098 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12099 mutex_init(&child->perf_event_mutex);
12100 INIT_LIST_HEAD(&child->perf_event_list);
12102 for_each_task_context_nr(ctxn) {
12103 ret = perf_event_init_context(child, ctxn);
12105 perf_event_free_task(child);
12113 static void __init perf_event_init_all_cpus(void)
12115 struct swevent_htable *swhash;
12118 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12120 for_each_possible_cpu(cpu) {
12121 swhash = &per_cpu(swevent_htable, cpu);
12122 mutex_init(&swhash->hlist_mutex);
12123 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12125 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12126 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12128 #ifdef CONFIG_CGROUP_PERF
12129 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12131 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12135 static void perf_swevent_init_cpu(unsigned int cpu)
12137 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12139 mutex_lock(&swhash->hlist_mutex);
12140 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12141 struct swevent_hlist *hlist;
12143 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12145 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12147 mutex_unlock(&swhash->hlist_mutex);
12150 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12151 static void __perf_event_exit_context(void *__info)
12153 struct perf_event_context *ctx = __info;
12154 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12155 struct perf_event *event;
12157 raw_spin_lock(&ctx->lock);
12158 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12159 list_for_each_entry(event, &ctx->event_list, event_entry)
12160 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12161 raw_spin_unlock(&ctx->lock);
12164 static void perf_event_exit_cpu_context(int cpu)
12166 struct perf_cpu_context *cpuctx;
12167 struct perf_event_context *ctx;
12170 mutex_lock(&pmus_lock);
12171 list_for_each_entry(pmu, &pmus, entry) {
12172 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12173 ctx = &cpuctx->ctx;
12175 mutex_lock(&ctx->mutex);
12176 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12177 cpuctx->online = 0;
12178 mutex_unlock(&ctx->mutex);
12180 cpumask_clear_cpu(cpu, perf_online_mask);
12181 mutex_unlock(&pmus_lock);
12185 static void perf_event_exit_cpu_context(int cpu) { }
12189 int perf_event_init_cpu(unsigned int cpu)
12191 struct perf_cpu_context *cpuctx;
12192 struct perf_event_context *ctx;
12195 perf_swevent_init_cpu(cpu);
12197 mutex_lock(&pmus_lock);
12198 cpumask_set_cpu(cpu, perf_online_mask);
12199 list_for_each_entry(pmu, &pmus, entry) {
12200 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12201 ctx = &cpuctx->ctx;
12203 mutex_lock(&ctx->mutex);
12204 cpuctx->online = 1;
12205 mutex_unlock(&ctx->mutex);
12207 mutex_unlock(&pmus_lock);
12212 int perf_event_exit_cpu(unsigned int cpu)
12214 perf_event_exit_cpu_context(cpu);
12219 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12223 for_each_online_cpu(cpu)
12224 perf_event_exit_cpu(cpu);
12230 * Run the perf reboot notifier at the very last possible moment so that
12231 * the generic watchdog code runs as long as possible.
12233 static struct notifier_block perf_reboot_notifier = {
12234 .notifier_call = perf_reboot,
12235 .priority = INT_MIN,
12238 void __init perf_event_init(void)
12242 idr_init(&pmu_idr);
12244 perf_event_init_all_cpus();
12245 init_srcu_struct(&pmus_srcu);
12246 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12247 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12248 perf_pmu_register(&perf_task_clock, NULL, -1);
12249 perf_tp_register();
12250 perf_event_init_cpu(smp_processor_id());
12251 register_reboot_notifier(&perf_reboot_notifier);
12253 ret = init_hw_breakpoint();
12254 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12257 * Build time assertion that we keep the data_head at the intended
12258 * location. IOW, validation we got the __reserved[] size right.
12260 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12264 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12267 struct perf_pmu_events_attr *pmu_attr =
12268 container_of(attr, struct perf_pmu_events_attr, attr);
12270 if (pmu_attr->event_str)
12271 return sprintf(page, "%s\n", pmu_attr->event_str);
12275 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12277 static int __init perf_event_sysfs_init(void)
12282 mutex_lock(&pmus_lock);
12284 ret = bus_register(&pmu_bus);
12288 list_for_each_entry(pmu, &pmus, entry) {
12289 if (!pmu->name || pmu->type < 0)
12292 ret = pmu_dev_alloc(pmu);
12293 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12295 pmu_bus_running = 1;
12299 mutex_unlock(&pmus_lock);
12303 device_initcall(perf_event_sysfs_init);
12305 #ifdef CONFIG_CGROUP_PERF
12306 static struct cgroup_subsys_state *
12307 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12309 struct perf_cgroup *jc;
12311 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12313 return ERR_PTR(-ENOMEM);
12315 jc->info = alloc_percpu(struct perf_cgroup_info);
12318 return ERR_PTR(-ENOMEM);
12324 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12326 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12328 free_percpu(jc->info);
12332 static int __perf_cgroup_move(void *info)
12334 struct task_struct *task = info;
12336 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12341 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12343 struct task_struct *task;
12344 struct cgroup_subsys_state *css;
12346 cgroup_taskset_for_each(task, css, tset)
12347 task_function_call(task, __perf_cgroup_move, task);
12350 struct cgroup_subsys perf_event_cgrp_subsys = {
12351 .css_alloc = perf_cgroup_css_alloc,
12352 .css_free = perf_cgroup_css_free,
12353 .attach = perf_cgroup_attach,
12355 * Implicitly enable on dfl hierarchy so that perf events can
12356 * always be filtered by cgroup2 path as long as perf_event
12357 * controller is not mounted on a legacy hierarchy.
12359 .implicit_on_dfl = true,
12362 #endif /* CONFIG_CGROUP_PERF */