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 * @ctx == &cpuctx->ctx.
956 cpuctx = container_of(ctx, struct perf_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,
983 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
985 list_del(cpuctx_entry);
988 #else /* !CONFIG_CGROUP_PERF */
991 perf_cgroup_match(struct perf_event *event)
996 static inline void perf_detach_cgroup(struct perf_event *event)
999 static inline int is_cgroup_event(struct perf_event *event)
1004 static inline void update_cgrp_time_from_event(struct perf_event *event)
1008 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1012 static inline void perf_cgroup_sched_out(struct task_struct *task,
1013 struct task_struct *next)
1017 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1018 struct task_struct *task)
1022 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1023 struct perf_event_attr *attr,
1024 struct perf_event *group_leader)
1030 perf_cgroup_set_timestamp(struct task_struct *task,
1031 struct perf_event_context *ctx)
1036 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1041 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1045 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1051 list_update_cgroup_event(struct perf_event *event,
1052 struct perf_event_context *ctx, bool add)
1059 * set default to be dependent on timer tick just
1060 * like original code
1062 #define PERF_CPU_HRTIMER (1000 / HZ)
1064 * function must be called with interrupts disabled
1066 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1068 struct perf_cpu_context *cpuctx;
1071 lockdep_assert_irqs_disabled();
1073 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1074 rotations = perf_rotate_context(cpuctx);
1076 raw_spin_lock(&cpuctx->hrtimer_lock);
1078 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1080 cpuctx->hrtimer_active = 0;
1081 raw_spin_unlock(&cpuctx->hrtimer_lock);
1083 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1086 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1088 struct hrtimer *timer = &cpuctx->hrtimer;
1089 struct pmu *pmu = cpuctx->ctx.pmu;
1092 /* no multiplexing needed for SW PMU */
1093 if (pmu->task_ctx_nr == perf_sw_context)
1097 * check default is sane, if not set then force to
1098 * default interval (1/tick)
1100 interval = pmu->hrtimer_interval_ms;
1102 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1104 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1106 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1107 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1108 timer->function = perf_mux_hrtimer_handler;
1111 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1113 struct hrtimer *timer = &cpuctx->hrtimer;
1114 struct pmu *pmu = cpuctx->ctx.pmu;
1115 unsigned long flags;
1117 /* not for SW PMU */
1118 if (pmu->task_ctx_nr == perf_sw_context)
1121 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1122 if (!cpuctx->hrtimer_active) {
1123 cpuctx->hrtimer_active = 1;
1124 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1125 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1127 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1132 void perf_pmu_disable(struct pmu *pmu)
1134 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1136 pmu->pmu_disable(pmu);
1139 void perf_pmu_enable(struct pmu *pmu)
1141 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1143 pmu->pmu_enable(pmu);
1146 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1149 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1150 * perf_event_task_tick() are fully serialized because they're strictly cpu
1151 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1152 * disabled, while perf_event_task_tick is called from IRQ context.
1154 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1156 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1158 lockdep_assert_irqs_disabled();
1160 WARN_ON(!list_empty(&ctx->active_ctx_list));
1162 list_add(&ctx->active_ctx_list, head);
1165 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1167 lockdep_assert_irqs_disabled();
1169 WARN_ON(list_empty(&ctx->active_ctx_list));
1171 list_del_init(&ctx->active_ctx_list);
1174 static void get_ctx(struct perf_event_context *ctx)
1176 refcount_inc(&ctx->refcount);
1179 static void free_ctx(struct rcu_head *head)
1181 struct perf_event_context *ctx;
1183 ctx = container_of(head, struct perf_event_context, rcu_head);
1184 kfree(ctx->task_ctx_data);
1188 static void put_ctx(struct perf_event_context *ctx)
1190 if (refcount_dec_and_test(&ctx->refcount)) {
1191 if (ctx->parent_ctx)
1192 put_ctx(ctx->parent_ctx);
1193 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1194 put_task_struct(ctx->task);
1195 call_rcu(&ctx->rcu_head, free_ctx);
1200 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1201 * perf_pmu_migrate_context() we need some magic.
1203 * Those places that change perf_event::ctx will hold both
1204 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1206 * Lock ordering is by mutex address. There are two other sites where
1207 * perf_event_context::mutex nests and those are:
1209 * - perf_event_exit_task_context() [ child , 0 ]
1210 * perf_event_exit_event()
1211 * put_event() [ parent, 1 ]
1213 * - perf_event_init_context() [ parent, 0 ]
1214 * inherit_task_group()
1217 * perf_event_alloc()
1219 * perf_try_init_event() [ child , 1 ]
1221 * While it appears there is an obvious deadlock here -- the parent and child
1222 * nesting levels are inverted between the two. This is in fact safe because
1223 * life-time rules separate them. That is an exiting task cannot fork, and a
1224 * spawning task cannot (yet) exit.
1226 * But remember that that these are parent<->child context relations, and
1227 * migration does not affect children, therefore these two orderings should not
1230 * The change in perf_event::ctx does not affect children (as claimed above)
1231 * because the sys_perf_event_open() case will install a new event and break
1232 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1233 * concerned with cpuctx and that doesn't have children.
1235 * The places that change perf_event::ctx will issue:
1237 * perf_remove_from_context();
1238 * synchronize_rcu();
1239 * perf_install_in_context();
1241 * to affect the change. The remove_from_context() + synchronize_rcu() should
1242 * quiesce the event, after which we can install it in the new location. This
1243 * means that only external vectors (perf_fops, prctl) can perturb the event
1244 * while in transit. Therefore all such accessors should also acquire
1245 * perf_event_context::mutex to serialize against this.
1247 * However; because event->ctx can change while we're waiting to acquire
1248 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1253 * task_struct::perf_event_mutex
1254 * perf_event_context::mutex
1255 * perf_event::child_mutex;
1256 * perf_event_context::lock
1257 * perf_event::mmap_mutex
1259 * perf_addr_filters_head::lock
1263 * cpuctx->mutex / perf_event_context::mutex
1265 static struct perf_event_context *
1266 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1268 struct perf_event_context *ctx;
1272 ctx = READ_ONCE(event->ctx);
1273 if (!refcount_inc_not_zero(&ctx->refcount)) {
1279 mutex_lock_nested(&ctx->mutex, nesting);
1280 if (event->ctx != ctx) {
1281 mutex_unlock(&ctx->mutex);
1289 static inline struct perf_event_context *
1290 perf_event_ctx_lock(struct perf_event *event)
1292 return perf_event_ctx_lock_nested(event, 0);
1295 static void perf_event_ctx_unlock(struct perf_event *event,
1296 struct perf_event_context *ctx)
1298 mutex_unlock(&ctx->mutex);
1303 * This must be done under the ctx->lock, such as to serialize against
1304 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1305 * calling scheduler related locks and ctx->lock nests inside those.
1307 static __must_check struct perf_event_context *
1308 unclone_ctx(struct perf_event_context *ctx)
1310 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1312 lockdep_assert_held(&ctx->lock);
1315 ctx->parent_ctx = NULL;
1321 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1326 * only top level events have the pid namespace they were created in
1329 event = event->parent;
1331 nr = __task_pid_nr_ns(p, type, event->ns);
1332 /* avoid -1 if it is idle thread or runs in another ns */
1333 if (!nr && !pid_alive(p))
1338 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1340 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1343 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1345 return perf_event_pid_type(event, p, PIDTYPE_PID);
1349 * If we inherit events we want to return the parent event id
1352 static u64 primary_event_id(struct perf_event *event)
1357 id = event->parent->id;
1363 * Get the perf_event_context for a task and lock it.
1365 * This has to cope with with the fact that until it is locked,
1366 * the context could get moved to another task.
1368 static struct perf_event_context *
1369 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1371 struct perf_event_context *ctx;
1375 * One of the few rules of preemptible RCU is that one cannot do
1376 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1377 * part of the read side critical section was irqs-enabled -- see
1378 * rcu_read_unlock_special().
1380 * Since ctx->lock nests under rq->lock we must ensure the entire read
1381 * side critical section has interrupts disabled.
1383 local_irq_save(*flags);
1385 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1388 * If this context is a clone of another, it might
1389 * get swapped for another underneath us by
1390 * perf_event_task_sched_out, though the
1391 * rcu_read_lock() protects us from any context
1392 * getting freed. Lock the context and check if it
1393 * got swapped before we could get the lock, and retry
1394 * if so. If we locked the right context, then it
1395 * can't get swapped on us any more.
1397 raw_spin_lock(&ctx->lock);
1398 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1399 raw_spin_unlock(&ctx->lock);
1401 local_irq_restore(*flags);
1405 if (ctx->task == TASK_TOMBSTONE ||
1406 !refcount_inc_not_zero(&ctx->refcount)) {
1407 raw_spin_unlock(&ctx->lock);
1410 WARN_ON_ONCE(ctx->task != task);
1415 local_irq_restore(*flags);
1420 * Get the context for a task and increment its pin_count so it
1421 * can't get swapped to another task. This also increments its
1422 * reference count so that the context can't get freed.
1424 static struct perf_event_context *
1425 perf_pin_task_context(struct task_struct *task, int ctxn)
1427 struct perf_event_context *ctx;
1428 unsigned long flags;
1430 ctx = perf_lock_task_context(task, ctxn, &flags);
1433 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1438 static void perf_unpin_context(struct perf_event_context *ctx)
1440 unsigned long flags;
1442 raw_spin_lock_irqsave(&ctx->lock, flags);
1444 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1448 * Update the record of the current time in a context.
1450 static void update_context_time(struct perf_event_context *ctx)
1452 u64 now = perf_clock();
1454 ctx->time += now - ctx->timestamp;
1455 ctx->timestamp = now;
1458 static u64 perf_event_time(struct perf_event *event)
1460 struct perf_event_context *ctx = event->ctx;
1462 if (is_cgroup_event(event))
1463 return perf_cgroup_event_time(event);
1465 return ctx ? ctx->time : 0;
1468 static enum event_type_t get_event_type(struct perf_event *event)
1470 struct perf_event_context *ctx = event->ctx;
1471 enum event_type_t event_type;
1473 lockdep_assert_held(&ctx->lock);
1476 * It's 'group type', really, because if our group leader is
1477 * pinned, so are we.
1479 if (event->group_leader != event)
1480 event = event->group_leader;
1482 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1484 event_type |= EVENT_CPU;
1490 * Helper function to initialize event group nodes.
1492 static void init_event_group(struct perf_event *event)
1494 RB_CLEAR_NODE(&event->group_node);
1495 event->group_index = 0;
1499 * Extract pinned or flexible groups from the context
1500 * based on event attrs bits.
1502 static struct perf_event_groups *
1503 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1505 if (event->attr.pinned)
1506 return &ctx->pinned_groups;
1508 return &ctx->flexible_groups;
1512 * Helper function to initializes perf_event_group trees.
1514 static void perf_event_groups_init(struct perf_event_groups *groups)
1516 groups->tree = RB_ROOT;
1521 * Compare function for event groups;
1523 * Implements complex key that first sorts by CPU and then by virtual index
1524 * which provides ordering when rotating groups for the same CPU.
1527 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1529 if (left->cpu < right->cpu)
1531 if (left->cpu > right->cpu)
1534 if (left->group_index < right->group_index)
1536 if (left->group_index > right->group_index)
1543 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1544 * key (see perf_event_groups_less). This places it last inside the CPU
1548 perf_event_groups_insert(struct perf_event_groups *groups,
1549 struct perf_event *event)
1551 struct perf_event *node_event;
1552 struct rb_node *parent;
1553 struct rb_node **node;
1555 event->group_index = ++groups->index;
1557 node = &groups->tree.rb_node;
1562 node_event = container_of(*node, struct perf_event, group_node);
1564 if (perf_event_groups_less(event, node_event))
1565 node = &parent->rb_left;
1567 node = &parent->rb_right;
1570 rb_link_node(&event->group_node, parent, node);
1571 rb_insert_color(&event->group_node, &groups->tree);
1575 * Helper function to insert event into the pinned or flexible groups.
1578 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1580 struct perf_event_groups *groups;
1582 groups = get_event_groups(event, ctx);
1583 perf_event_groups_insert(groups, event);
1587 * Delete a group from a tree.
1590 perf_event_groups_delete(struct perf_event_groups *groups,
1591 struct perf_event *event)
1593 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1594 RB_EMPTY_ROOT(&groups->tree));
1596 rb_erase(&event->group_node, &groups->tree);
1597 init_event_group(event);
1601 * Helper function to delete event from its groups.
1604 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1606 struct perf_event_groups *groups;
1608 groups = get_event_groups(event, ctx);
1609 perf_event_groups_delete(groups, event);
1613 * Get the leftmost event in the @cpu subtree.
1615 static struct perf_event *
1616 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1618 struct perf_event *node_event = NULL, *match = NULL;
1619 struct rb_node *node = groups->tree.rb_node;
1622 node_event = container_of(node, struct perf_event, group_node);
1624 if (cpu < node_event->cpu) {
1625 node = node->rb_left;
1626 } else if (cpu > node_event->cpu) {
1627 node = node->rb_right;
1630 node = node->rb_left;
1638 * Like rb_entry_next_safe() for the @cpu subtree.
1640 static struct perf_event *
1641 perf_event_groups_next(struct perf_event *event)
1643 struct perf_event *next;
1645 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1646 if (next && next->cpu == event->cpu)
1653 * Iterate through the whole groups tree.
1655 #define perf_event_groups_for_each(event, groups) \
1656 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1657 typeof(*event), group_node); event; \
1658 event = rb_entry_safe(rb_next(&event->group_node), \
1659 typeof(*event), group_node))
1662 * Add an event from the lists for its context.
1663 * Must be called with ctx->mutex and ctx->lock held.
1666 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1668 lockdep_assert_held(&ctx->lock);
1670 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1671 event->attach_state |= PERF_ATTACH_CONTEXT;
1673 event->tstamp = perf_event_time(event);
1676 * If we're a stand alone event or group leader, we go to the context
1677 * list, group events are kept attached to the group so that
1678 * perf_group_detach can, at all times, locate all siblings.
1680 if (event->group_leader == event) {
1681 event->group_caps = event->event_caps;
1682 add_event_to_groups(event, ctx);
1685 list_update_cgroup_event(event, ctx, true);
1687 list_add_rcu(&event->event_entry, &ctx->event_list);
1689 if (event->attr.inherit_stat)
1696 * Initialize event state based on the perf_event_attr::disabled.
1698 static inline void perf_event__state_init(struct perf_event *event)
1700 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1701 PERF_EVENT_STATE_INACTIVE;
1704 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1706 int entry = sizeof(u64); /* value */
1710 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1711 size += sizeof(u64);
1713 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1714 size += sizeof(u64);
1716 if (event->attr.read_format & PERF_FORMAT_ID)
1717 entry += sizeof(u64);
1719 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1721 size += sizeof(u64);
1725 event->read_size = size;
1728 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1730 struct perf_sample_data *data;
1733 if (sample_type & PERF_SAMPLE_IP)
1734 size += sizeof(data->ip);
1736 if (sample_type & PERF_SAMPLE_ADDR)
1737 size += sizeof(data->addr);
1739 if (sample_type & PERF_SAMPLE_PERIOD)
1740 size += sizeof(data->period);
1742 if (sample_type & PERF_SAMPLE_WEIGHT)
1743 size += sizeof(data->weight);
1745 if (sample_type & PERF_SAMPLE_READ)
1746 size += event->read_size;
1748 if (sample_type & PERF_SAMPLE_DATA_SRC)
1749 size += sizeof(data->data_src.val);
1751 if (sample_type & PERF_SAMPLE_TRANSACTION)
1752 size += sizeof(data->txn);
1754 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1755 size += sizeof(data->phys_addr);
1757 event->header_size = size;
1761 * Called at perf_event creation and when events are attached/detached from a
1764 static void perf_event__header_size(struct perf_event *event)
1766 __perf_event_read_size(event,
1767 event->group_leader->nr_siblings);
1768 __perf_event_header_size(event, event->attr.sample_type);
1771 static void perf_event__id_header_size(struct perf_event *event)
1773 struct perf_sample_data *data;
1774 u64 sample_type = event->attr.sample_type;
1777 if (sample_type & PERF_SAMPLE_TID)
1778 size += sizeof(data->tid_entry);
1780 if (sample_type & PERF_SAMPLE_TIME)
1781 size += sizeof(data->time);
1783 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1784 size += sizeof(data->id);
1786 if (sample_type & PERF_SAMPLE_ID)
1787 size += sizeof(data->id);
1789 if (sample_type & PERF_SAMPLE_STREAM_ID)
1790 size += sizeof(data->stream_id);
1792 if (sample_type & PERF_SAMPLE_CPU)
1793 size += sizeof(data->cpu_entry);
1795 event->id_header_size = size;
1798 static bool perf_event_validate_size(struct perf_event *event)
1801 * The values computed here will be over-written when we actually
1804 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1805 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1806 perf_event__id_header_size(event);
1809 * Sum the lot; should not exceed the 64k limit we have on records.
1810 * Conservative limit to allow for callchains and other variable fields.
1812 if (event->read_size + event->header_size +
1813 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1819 static void perf_group_attach(struct perf_event *event)
1821 struct perf_event *group_leader = event->group_leader, *pos;
1823 lockdep_assert_held(&event->ctx->lock);
1826 * We can have double attach due to group movement in perf_event_open.
1828 if (event->attach_state & PERF_ATTACH_GROUP)
1831 event->attach_state |= PERF_ATTACH_GROUP;
1833 if (group_leader == event)
1836 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1838 group_leader->group_caps &= event->event_caps;
1840 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1841 group_leader->nr_siblings++;
1843 perf_event__header_size(group_leader);
1845 for_each_sibling_event(pos, group_leader)
1846 perf_event__header_size(pos);
1850 * Remove an event from the lists for its context.
1851 * Must be called with ctx->mutex and ctx->lock held.
1854 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1856 WARN_ON_ONCE(event->ctx != ctx);
1857 lockdep_assert_held(&ctx->lock);
1860 * We can have double detach due to exit/hot-unplug + close.
1862 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1865 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1867 list_update_cgroup_event(event, ctx, false);
1870 if (event->attr.inherit_stat)
1873 list_del_rcu(&event->event_entry);
1875 if (event->group_leader == event)
1876 del_event_from_groups(event, ctx);
1879 * If event was in error state, then keep it
1880 * that way, otherwise bogus counts will be
1881 * returned on read(). The only way to get out
1882 * of error state is by explicit re-enabling
1885 if (event->state > PERF_EVENT_STATE_OFF)
1886 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1892 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
1894 if (!has_aux(aux_event))
1897 if (!event->pmu->aux_output_match)
1900 return event->pmu->aux_output_match(aux_event);
1903 static void put_event(struct perf_event *event);
1904 static void event_sched_out(struct perf_event *event,
1905 struct perf_cpu_context *cpuctx,
1906 struct perf_event_context *ctx);
1908 static void perf_put_aux_event(struct perf_event *event)
1910 struct perf_event_context *ctx = event->ctx;
1911 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1912 struct perf_event *iter;
1915 * If event uses aux_event tear down the link
1917 if (event->aux_event) {
1918 iter = event->aux_event;
1919 event->aux_event = NULL;
1925 * If the event is an aux_event, tear down all links to
1926 * it from other events.
1928 for_each_sibling_event(iter, event->group_leader) {
1929 if (iter->aux_event != event)
1932 iter->aux_event = NULL;
1936 * If it's ACTIVE, schedule it out and put it into ERROR
1937 * state so that we don't try to schedule it again. Note
1938 * that perf_event_enable() will clear the ERROR status.
1940 event_sched_out(iter, cpuctx, ctx);
1941 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
1945 static bool perf_need_aux_event(struct perf_event *event)
1947 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
1950 static int perf_get_aux_event(struct perf_event *event,
1951 struct perf_event *group_leader)
1954 * Our group leader must be an aux event if we want to be
1955 * an aux_output. This way, the aux event will precede its
1956 * aux_output events in the group, and therefore will always
1963 * aux_output and aux_sample_size are mutually exclusive.
1965 if (event->attr.aux_output && event->attr.aux_sample_size)
1968 if (event->attr.aux_output &&
1969 !perf_aux_output_match(event, group_leader))
1972 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
1975 if (!atomic_long_inc_not_zero(&group_leader->refcount))
1979 * Link aux_outputs to their aux event; this is undone in
1980 * perf_group_detach() by perf_put_aux_event(). When the
1981 * group in torn down, the aux_output events loose their
1982 * link to the aux_event and can't schedule any more.
1984 event->aux_event = group_leader;
1989 static void perf_group_detach(struct perf_event *event)
1991 struct perf_event *sibling, *tmp;
1992 struct perf_event_context *ctx = event->ctx;
1994 lockdep_assert_held(&ctx->lock);
1997 * We can have double detach due to exit/hot-unplug + close.
1999 if (!(event->attach_state & PERF_ATTACH_GROUP))
2002 event->attach_state &= ~PERF_ATTACH_GROUP;
2004 perf_put_aux_event(event);
2007 * If this is a sibling, remove it from its group.
2009 if (event->group_leader != event) {
2010 list_del_init(&event->sibling_list);
2011 event->group_leader->nr_siblings--;
2016 * If this was a group event with sibling events then
2017 * upgrade the siblings to singleton events by adding them
2018 * to whatever list we are on.
2020 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2022 sibling->group_leader = sibling;
2023 list_del_init(&sibling->sibling_list);
2025 /* Inherit group flags from the previous leader */
2026 sibling->group_caps = event->group_caps;
2028 if (!RB_EMPTY_NODE(&event->group_node)) {
2029 add_event_to_groups(sibling, event->ctx);
2031 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
2032 struct list_head *list = sibling->attr.pinned ?
2033 &ctx->pinned_active : &ctx->flexible_active;
2035 list_add_tail(&sibling->active_list, list);
2039 WARN_ON_ONCE(sibling->ctx != event->ctx);
2043 perf_event__header_size(event->group_leader);
2045 for_each_sibling_event(tmp, event->group_leader)
2046 perf_event__header_size(tmp);
2049 static bool is_orphaned_event(struct perf_event *event)
2051 return event->state == PERF_EVENT_STATE_DEAD;
2054 static inline int __pmu_filter_match(struct perf_event *event)
2056 struct pmu *pmu = event->pmu;
2057 return pmu->filter_match ? pmu->filter_match(event) : 1;
2061 * Check whether we should attempt to schedule an event group based on
2062 * PMU-specific filtering. An event group can consist of HW and SW events,
2063 * potentially with a SW leader, so we must check all the filters, to
2064 * determine whether a group is schedulable:
2066 static inline int pmu_filter_match(struct perf_event *event)
2068 struct perf_event *sibling;
2070 if (!__pmu_filter_match(event))
2073 for_each_sibling_event(sibling, event) {
2074 if (!__pmu_filter_match(sibling))
2082 event_filter_match(struct perf_event *event)
2084 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2085 perf_cgroup_match(event) && pmu_filter_match(event);
2089 event_sched_out(struct perf_event *event,
2090 struct perf_cpu_context *cpuctx,
2091 struct perf_event_context *ctx)
2093 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2095 WARN_ON_ONCE(event->ctx != ctx);
2096 lockdep_assert_held(&ctx->lock);
2098 if (event->state != PERF_EVENT_STATE_ACTIVE)
2102 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2103 * we can schedule events _OUT_ individually through things like
2104 * __perf_remove_from_context().
2106 list_del_init(&event->active_list);
2108 perf_pmu_disable(event->pmu);
2110 event->pmu->del(event, 0);
2113 if (READ_ONCE(event->pending_disable) >= 0) {
2114 WRITE_ONCE(event->pending_disable, -1);
2115 state = PERF_EVENT_STATE_OFF;
2117 perf_event_set_state(event, state);
2119 if (!is_software_event(event))
2120 cpuctx->active_oncpu--;
2121 if (!--ctx->nr_active)
2122 perf_event_ctx_deactivate(ctx);
2123 if (event->attr.freq && event->attr.sample_freq)
2125 if (event->attr.exclusive || !cpuctx->active_oncpu)
2126 cpuctx->exclusive = 0;
2128 perf_pmu_enable(event->pmu);
2132 group_sched_out(struct perf_event *group_event,
2133 struct perf_cpu_context *cpuctx,
2134 struct perf_event_context *ctx)
2136 struct perf_event *event;
2138 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2141 perf_pmu_disable(ctx->pmu);
2143 event_sched_out(group_event, cpuctx, ctx);
2146 * Schedule out siblings (if any):
2148 for_each_sibling_event(event, group_event)
2149 event_sched_out(event, cpuctx, ctx);
2151 perf_pmu_enable(ctx->pmu);
2153 if (group_event->attr.exclusive)
2154 cpuctx->exclusive = 0;
2157 #define DETACH_GROUP 0x01UL
2160 * Cross CPU call to remove a performance event
2162 * We disable the event on the hardware level first. After that we
2163 * remove it from the context list.
2166 __perf_remove_from_context(struct perf_event *event,
2167 struct perf_cpu_context *cpuctx,
2168 struct perf_event_context *ctx,
2171 unsigned long flags = (unsigned long)info;
2173 if (ctx->is_active & EVENT_TIME) {
2174 update_context_time(ctx);
2175 update_cgrp_time_from_cpuctx(cpuctx);
2178 event_sched_out(event, cpuctx, ctx);
2179 if (flags & DETACH_GROUP)
2180 perf_group_detach(event);
2181 list_del_event(event, ctx);
2183 if (!ctx->nr_events && ctx->is_active) {
2186 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2187 cpuctx->task_ctx = NULL;
2193 * Remove the event from a task's (or a CPU's) list of events.
2195 * If event->ctx is a cloned context, callers must make sure that
2196 * every task struct that event->ctx->task could possibly point to
2197 * remains valid. This is OK when called from perf_release since
2198 * that only calls us on the top-level context, which can't be a clone.
2199 * When called from perf_event_exit_task, it's OK because the
2200 * context has been detached from its task.
2202 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2204 struct perf_event_context *ctx = event->ctx;
2206 lockdep_assert_held(&ctx->mutex);
2208 event_function_call(event, __perf_remove_from_context, (void *)flags);
2211 * The above event_function_call() can NO-OP when it hits
2212 * TASK_TOMBSTONE. In that case we must already have been detached
2213 * from the context (by perf_event_exit_event()) but the grouping
2214 * might still be in-tact.
2216 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2217 if ((flags & DETACH_GROUP) &&
2218 (event->attach_state & PERF_ATTACH_GROUP)) {
2220 * Since in that case we cannot possibly be scheduled, simply
2223 raw_spin_lock_irq(&ctx->lock);
2224 perf_group_detach(event);
2225 raw_spin_unlock_irq(&ctx->lock);
2230 * Cross CPU call to disable a performance event
2232 static void __perf_event_disable(struct perf_event *event,
2233 struct perf_cpu_context *cpuctx,
2234 struct perf_event_context *ctx,
2237 if (event->state < PERF_EVENT_STATE_INACTIVE)
2240 if (ctx->is_active & EVENT_TIME) {
2241 update_context_time(ctx);
2242 update_cgrp_time_from_event(event);
2245 if (event == event->group_leader)
2246 group_sched_out(event, cpuctx, ctx);
2248 event_sched_out(event, cpuctx, ctx);
2250 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2256 * If event->ctx is a cloned context, callers must make sure that
2257 * every task struct that event->ctx->task could possibly point to
2258 * remains valid. This condition is satisfied when called through
2259 * perf_event_for_each_child or perf_event_for_each because they
2260 * hold the top-level event's child_mutex, so any descendant that
2261 * goes to exit will block in perf_event_exit_event().
2263 * When called from perf_pending_event it's OK because event->ctx
2264 * is the current context on this CPU and preemption is disabled,
2265 * hence we can't get into perf_event_task_sched_out for this context.
2267 static void _perf_event_disable(struct perf_event *event)
2269 struct perf_event_context *ctx = event->ctx;
2271 raw_spin_lock_irq(&ctx->lock);
2272 if (event->state <= PERF_EVENT_STATE_OFF) {
2273 raw_spin_unlock_irq(&ctx->lock);
2276 raw_spin_unlock_irq(&ctx->lock);
2278 event_function_call(event, __perf_event_disable, NULL);
2281 void perf_event_disable_local(struct perf_event *event)
2283 event_function_local(event, __perf_event_disable, NULL);
2287 * Strictly speaking kernel users cannot create groups and therefore this
2288 * interface does not need the perf_event_ctx_lock() magic.
2290 void perf_event_disable(struct perf_event *event)
2292 struct perf_event_context *ctx;
2294 ctx = perf_event_ctx_lock(event);
2295 _perf_event_disable(event);
2296 perf_event_ctx_unlock(event, ctx);
2298 EXPORT_SYMBOL_GPL(perf_event_disable);
2300 void perf_event_disable_inatomic(struct perf_event *event)
2302 WRITE_ONCE(event->pending_disable, smp_processor_id());
2303 /* can fail, see perf_pending_event_disable() */
2304 irq_work_queue(&event->pending);
2307 static void perf_set_shadow_time(struct perf_event *event,
2308 struct perf_event_context *ctx)
2311 * use the correct time source for the time snapshot
2313 * We could get by without this by leveraging the
2314 * fact that to get to this function, the caller
2315 * has most likely already called update_context_time()
2316 * and update_cgrp_time_xx() and thus both timestamp
2317 * are identical (or very close). Given that tstamp is,
2318 * already adjusted for cgroup, we could say that:
2319 * tstamp - ctx->timestamp
2321 * tstamp - cgrp->timestamp.
2323 * Then, in perf_output_read(), the calculation would
2324 * work with no changes because:
2325 * - event is guaranteed scheduled in
2326 * - no scheduled out in between
2327 * - thus the timestamp would be the same
2329 * But this is a bit hairy.
2331 * So instead, we have an explicit cgroup call to remain
2332 * within the time time source all along. We believe it
2333 * is cleaner and simpler to understand.
2335 if (is_cgroup_event(event))
2336 perf_cgroup_set_shadow_time(event, event->tstamp);
2338 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2341 #define MAX_INTERRUPTS (~0ULL)
2343 static void perf_log_throttle(struct perf_event *event, int enable);
2344 static void perf_log_itrace_start(struct perf_event *event);
2347 event_sched_in(struct perf_event *event,
2348 struct perf_cpu_context *cpuctx,
2349 struct perf_event_context *ctx)
2353 lockdep_assert_held(&ctx->lock);
2355 if (event->state <= PERF_EVENT_STATE_OFF)
2358 WRITE_ONCE(event->oncpu, smp_processor_id());
2360 * Order event::oncpu write to happen before the ACTIVE state is
2361 * visible. This allows perf_event_{stop,read}() to observe the correct
2362 * ->oncpu if it sees ACTIVE.
2365 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2368 * Unthrottle events, since we scheduled we might have missed several
2369 * ticks already, also for a heavily scheduling task there is little
2370 * guarantee it'll get a tick in a timely manner.
2372 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2373 perf_log_throttle(event, 1);
2374 event->hw.interrupts = 0;
2377 perf_pmu_disable(event->pmu);
2379 perf_set_shadow_time(event, ctx);
2381 perf_log_itrace_start(event);
2383 if (event->pmu->add(event, PERF_EF_START)) {
2384 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2390 if (!is_software_event(event))
2391 cpuctx->active_oncpu++;
2392 if (!ctx->nr_active++)
2393 perf_event_ctx_activate(ctx);
2394 if (event->attr.freq && event->attr.sample_freq)
2397 if (event->attr.exclusive)
2398 cpuctx->exclusive = 1;
2401 perf_pmu_enable(event->pmu);
2407 group_sched_in(struct perf_event *group_event,
2408 struct perf_cpu_context *cpuctx,
2409 struct perf_event_context *ctx)
2411 struct perf_event *event, *partial_group = NULL;
2412 struct pmu *pmu = ctx->pmu;
2414 if (group_event->state == PERF_EVENT_STATE_OFF)
2417 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2419 if (event_sched_in(group_event, cpuctx, ctx)) {
2420 pmu->cancel_txn(pmu);
2421 perf_mux_hrtimer_restart(cpuctx);
2426 * Schedule in siblings as one group (if any):
2428 for_each_sibling_event(event, group_event) {
2429 if (event_sched_in(event, cpuctx, ctx)) {
2430 partial_group = event;
2435 if (!pmu->commit_txn(pmu))
2440 * Groups can be scheduled in as one unit only, so undo any
2441 * partial group before returning:
2442 * The events up to the failed event are scheduled out normally.
2444 for_each_sibling_event(event, group_event) {
2445 if (event == partial_group)
2448 event_sched_out(event, cpuctx, ctx);
2450 event_sched_out(group_event, cpuctx, ctx);
2452 pmu->cancel_txn(pmu);
2454 perf_mux_hrtimer_restart(cpuctx);
2460 * Work out whether we can put this event group on the CPU now.
2462 static int group_can_go_on(struct perf_event *event,
2463 struct perf_cpu_context *cpuctx,
2467 * Groups consisting entirely of software events can always go on.
2469 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2472 * If an exclusive group is already on, no other hardware
2475 if (cpuctx->exclusive)
2478 * If this group is exclusive and there are already
2479 * events on the CPU, it can't go on.
2481 if (event->attr.exclusive && cpuctx->active_oncpu)
2484 * Otherwise, try to add it if all previous groups were able
2490 static void add_event_to_ctx(struct perf_event *event,
2491 struct perf_event_context *ctx)
2493 list_add_event(event, ctx);
2494 perf_group_attach(event);
2497 static void ctx_sched_out(struct perf_event_context *ctx,
2498 struct perf_cpu_context *cpuctx,
2499 enum event_type_t event_type);
2501 ctx_sched_in(struct perf_event_context *ctx,
2502 struct perf_cpu_context *cpuctx,
2503 enum event_type_t event_type,
2504 struct task_struct *task);
2506 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2507 struct perf_event_context *ctx,
2508 enum event_type_t event_type)
2510 if (!cpuctx->task_ctx)
2513 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2516 ctx_sched_out(ctx, cpuctx, event_type);
2519 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2520 struct perf_event_context *ctx,
2521 struct task_struct *task)
2523 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2525 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2526 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2528 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2532 * We want to maintain the following priority of scheduling:
2533 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2534 * - task pinned (EVENT_PINNED)
2535 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2536 * - task flexible (EVENT_FLEXIBLE).
2538 * In order to avoid unscheduling and scheduling back in everything every
2539 * time an event is added, only do it for the groups of equal priority and
2542 * This can be called after a batch operation on task events, in which case
2543 * event_type is a bit mask of the types of events involved. For CPU events,
2544 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2546 static void ctx_resched(struct perf_cpu_context *cpuctx,
2547 struct perf_event_context *task_ctx,
2548 enum event_type_t event_type)
2550 enum event_type_t ctx_event_type;
2551 bool cpu_event = !!(event_type & EVENT_CPU);
2554 * If pinned groups are involved, flexible groups also need to be
2557 if (event_type & EVENT_PINNED)
2558 event_type |= EVENT_FLEXIBLE;
2560 ctx_event_type = event_type & EVENT_ALL;
2562 perf_pmu_disable(cpuctx->ctx.pmu);
2564 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2567 * Decide which cpu ctx groups to schedule out based on the types
2568 * of events that caused rescheduling:
2569 * - EVENT_CPU: schedule out corresponding groups;
2570 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2571 * - otherwise, do nothing more.
2574 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2575 else if (ctx_event_type & EVENT_PINNED)
2576 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2578 perf_event_sched_in(cpuctx, task_ctx, current);
2579 perf_pmu_enable(cpuctx->ctx.pmu);
2582 void perf_pmu_resched(struct pmu *pmu)
2584 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2585 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2587 perf_ctx_lock(cpuctx, task_ctx);
2588 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2589 perf_ctx_unlock(cpuctx, task_ctx);
2593 * Cross CPU call to install and enable a performance event
2595 * Very similar to remote_function() + event_function() but cannot assume that
2596 * things like ctx->is_active and cpuctx->task_ctx are set.
2598 static int __perf_install_in_context(void *info)
2600 struct perf_event *event = info;
2601 struct perf_event_context *ctx = event->ctx;
2602 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2603 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2604 bool reprogram = true;
2607 raw_spin_lock(&cpuctx->ctx.lock);
2609 raw_spin_lock(&ctx->lock);
2612 reprogram = (ctx->task == current);
2615 * If the task is running, it must be running on this CPU,
2616 * otherwise we cannot reprogram things.
2618 * If its not running, we don't care, ctx->lock will
2619 * serialize against it becoming runnable.
2621 if (task_curr(ctx->task) && !reprogram) {
2626 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2627 } else if (task_ctx) {
2628 raw_spin_lock(&task_ctx->lock);
2631 #ifdef CONFIG_CGROUP_PERF
2632 if (is_cgroup_event(event)) {
2634 * If the current cgroup doesn't match the event's
2635 * cgroup, we should not try to schedule it.
2637 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2638 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2639 event->cgrp->css.cgroup);
2644 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2645 add_event_to_ctx(event, ctx);
2646 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2648 add_event_to_ctx(event, ctx);
2652 perf_ctx_unlock(cpuctx, task_ctx);
2657 static bool exclusive_event_installable(struct perf_event *event,
2658 struct perf_event_context *ctx);
2661 * Attach a performance event to a context.
2663 * Very similar to event_function_call, see comment there.
2666 perf_install_in_context(struct perf_event_context *ctx,
2667 struct perf_event *event,
2670 struct task_struct *task = READ_ONCE(ctx->task);
2672 lockdep_assert_held(&ctx->mutex);
2674 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2676 if (event->cpu != -1)
2680 * Ensures that if we can observe event->ctx, both the event and ctx
2681 * will be 'complete'. See perf_iterate_sb_cpu().
2683 smp_store_release(&event->ctx, ctx);
2686 * perf_event_attr::disabled events will not run and can be initialized
2687 * without IPI. Except when this is the first event for the context, in
2688 * that case we need the magic of the IPI to set ctx->is_active.
2690 * The IOC_ENABLE that is sure to follow the creation of a disabled
2691 * event will issue the IPI and reprogram the hardware.
2693 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2694 raw_spin_lock_irq(&ctx->lock);
2695 if (ctx->task == TASK_TOMBSTONE) {
2696 raw_spin_unlock_irq(&ctx->lock);
2699 add_event_to_ctx(event, ctx);
2700 raw_spin_unlock_irq(&ctx->lock);
2705 cpu_function_call(cpu, __perf_install_in_context, event);
2710 * Should not happen, we validate the ctx is still alive before calling.
2712 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2716 * Installing events is tricky because we cannot rely on ctx->is_active
2717 * to be set in case this is the nr_events 0 -> 1 transition.
2719 * Instead we use task_curr(), which tells us if the task is running.
2720 * However, since we use task_curr() outside of rq::lock, we can race
2721 * against the actual state. This means the result can be wrong.
2723 * If we get a false positive, we retry, this is harmless.
2725 * If we get a false negative, things are complicated. If we are after
2726 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2727 * value must be correct. If we're before, it doesn't matter since
2728 * perf_event_context_sched_in() will program the counter.
2730 * However, this hinges on the remote context switch having observed
2731 * our task->perf_event_ctxp[] store, such that it will in fact take
2732 * ctx::lock in perf_event_context_sched_in().
2734 * We do this by task_function_call(), if the IPI fails to hit the task
2735 * we know any future context switch of task must see the
2736 * perf_event_ctpx[] store.
2740 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2741 * task_cpu() load, such that if the IPI then does not find the task
2742 * running, a future context switch of that task must observe the
2747 if (!task_function_call(task, __perf_install_in_context, event))
2750 raw_spin_lock_irq(&ctx->lock);
2752 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2754 * Cannot happen because we already checked above (which also
2755 * cannot happen), and we hold ctx->mutex, which serializes us
2756 * against perf_event_exit_task_context().
2758 raw_spin_unlock_irq(&ctx->lock);
2762 * If the task is not running, ctx->lock will avoid it becoming so,
2763 * thus we can safely install the event.
2765 if (task_curr(task)) {
2766 raw_spin_unlock_irq(&ctx->lock);
2769 add_event_to_ctx(event, ctx);
2770 raw_spin_unlock_irq(&ctx->lock);
2774 * Cross CPU call to enable a performance event
2776 static void __perf_event_enable(struct perf_event *event,
2777 struct perf_cpu_context *cpuctx,
2778 struct perf_event_context *ctx,
2781 struct perf_event *leader = event->group_leader;
2782 struct perf_event_context *task_ctx;
2784 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2785 event->state <= PERF_EVENT_STATE_ERROR)
2789 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2791 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2793 if (!ctx->is_active)
2796 if (!event_filter_match(event)) {
2797 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2802 * If the event is in a group and isn't the group leader,
2803 * then don't put it on unless the group is on.
2805 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2806 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2810 task_ctx = cpuctx->task_ctx;
2812 WARN_ON_ONCE(task_ctx != ctx);
2814 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2820 * If event->ctx is a cloned context, callers must make sure that
2821 * every task struct that event->ctx->task could possibly point to
2822 * remains valid. This condition is satisfied when called through
2823 * perf_event_for_each_child or perf_event_for_each as described
2824 * for perf_event_disable.
2826 static void _perf_event_enable(struct perf_event *event)
2828 struct perf_event_context *ctx = event->ctx;
2830 raw_spin_lock_irq(&ctx->lock);
2831 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2832 event->state < PERF_EVENT_STATE_ERROR) {
2833 raw_spin_unlock_irq(&ctx->lock);
2838 * If the event is in error state, clear that first.
2840 * That way, if we see the event in error state below, we know that it
2841 * has gone back into error state, as distinct from the task having
2842 * been scheduled away before the cross-call arrived.
2844 if (event->state == PERF_EVENT_STATE_ERROR)
2845 event->state = PERF_EVENT_STATE_OFF;
2846 raw_spin_unlock_irq(&ctx->lock);
2848 event_function_call(event, __perf_event_enable, NULL);
2852 * See perf_event_disable();
2854 void perf_event_enable(struct perf_event *event)
2856 struct perf_event_context *ctx;
2858 ctx = perf_event_ctx_lock(event);
2859 _perf_event_enable(event);
2860 perf_event_ctx_unlock(event, ctx);
2862 EXPORT_SYMBOL_GPL(perf_event_enable);
2864 struct stop_event_data {
2865 struct perf_event *event;
2866 unsigned int restart;
2869 static int __perf_event_stop(void *info)
2871 struct stop_event_data *sd = info;
2872 struct perf_event *event = sd->event;
2874 /* if it's already INACTIVE, do nothing */
2875 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2878 /* matches smp_wmb() in event_sched_in() */
2882 * There is a window with interrupts enabled before we get here,
2883 * so we need to check again lest we try to stop another CPU's event.
2885 if (READ_ONCE(event->oncpu) != smp_processor_id())
2888 event->pmu->stop(event, PERF_EF_UPDATE);
2891 * May race with the actual stop (through perf_pmu_output_stop()),
2892 * but it is only used for events with AUX ring buffer, and such
2893 * events will refuse to restart because of rb::aux_mmap_count==0,
2894 * see comments in perf_aux_output_begin().
2896 * Since this is happening on an event-local CPU, no trace is lost
2900 event->pmu->start(event, 0);
2905 static int perf_event_stop(struct perf_event *event, int restart)
2907 struct stop_event_data sd = {
2914 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2917 /* matches smp_wmb() in event_sched_in() */
2921 * We only want to restart ACTIVE events, so if the event goes
2922 * inactive here (event->oncpu==-1), there's nothing more to do;
2923 * fall through with ret==-ENXIO.
2925 ret = cpu_function_call(READ_ONCE(event->oncpu),
2926 __perf_event_stop, &sd);
2927 } while (ret == -EAGAIN);
2933 * In order to contain the amount of racy and tricky in the address filter
2934 * configuration management, it is a two part process:
2936 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2937 * we update the addresses of corresponding vmas in
2938 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2939 * (p2) when an event is scheduled in (pmu::add), it calls
2940 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2941 * if the generation has changed since the previous call.
2943 * If (p1) happens while the event is active, we restart it to force (p2).
2945 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2946 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2948 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2949 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2951 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2954 void perf_event_addr_filters_sync(struct perf_event *event)
2956 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2958 if (!has_addr_filter(event))
2961 raw_spin_lock(&ifh->lock);
2962 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2963 event->pmu->addr_filters_sync(event);
2964 event->hw.addr_filters_gen = event->addr_filters_gen;
2966 raw_spin_unlock(&ifh->lock);
2968 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2970 static int _perf_event_refresh(struct perf_event *event, int refresh)
2973 * not supported on inherited events
2975 if (event->attr.inherit || !is_sampling_event(event))
2978 atomic_add(refresh, &event->event_limit);
2979 _perf_event_enable(event);
2985 * See perf_event_disable()
2987 int perf_event_refresh(struct perf_event *event, int refresh)
2989 struct perf_event_context *ctx;
2992 ctx = perf_event_ctx_lock(event);
2993 ret = _perf_event_refresh(event, refresh);
2994 perf_event_ctx_unlock(event, ctx);
2998 EXPORT_SYMBOL_GPL(perf_event_refresh);
3000 static int perf_event_modify_breakpoint(struct perf_event *bp,
3001 struct perf_event_attr *attr)
3005 _perf_event_disable(bp);
3007 err = modify_user_hw_breakpoint_check(bp, attr, true);
3009 if (!bp->attr.disabled)
3010 _perf_event_enable(bp);
3015 static int perf_event_modify_attr(struct perf_event *event,
3016 struct perf_event_attr *attr)
3018 if (event->attr.type != attr->type)
3021 switch (event->attr.type) {
3022 case PERF_TYPE_BREAKPOINT:
3023 return perf_event_modify_breakpoint(event, attr);
3025 /* Place holder for future additions. */
3030 static void ctx_sched_out(struct perf_event_context *ctx,
3031 struct perf_cpu_context *cpuctx,
3032 enum event_type_t event_type)
3034 struct perf_event *event, *tmp;
3035 int is_active = ctx->is_active;
3037 lockdep_assert_held(&ctx->lock);
3039 if (likely(!ctx->nr_events)) {
3041 * See __perf_remove_from_context().
3043 WARN_ON_ONCE(ctx->is_active);
3045 WARN_ON_ONCE(cpuctx->task_ctx);
3049 ctx->is_active &= ~event_type;
3050 if (!(ctx->is_active & EVENT_ALL))
3054 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3055 if (!ctx->is_active)
3056 cpuctx->task_ctx = NULL;
3060 * Always update time if it was set; not only when it changes.
3061 * Otherwise we can 'forget' to update time for any but the last
3062 * context we sched out. For example:
3064 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3065 * ctx_sched_out(.event_type = EVENT_PINNED)
3067 * would only update time for the pinned events.
3069 if (is_active & EVENT_TIME) {
3070 /* update (and stop) ctx time */
3071 update_context_time(ctx);
3072 update_cgrp_time_from_cpuctx(cpuctx);
3075 is_active ^= ctx->is_active; /* changed bits */
3077 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3081 * If we had been multiplexing, no rotations are necessary, now no events
3084 ctx->rotate_necessary = 0;
3086 perf_pmu_disable(ctx->pmu);
3087 if (is_active & EVENT_PINNED) {
3088 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3089 group_sched_out(event, cpuctx, ctx);
3092 if (is_active & EVENT_FLEXIBLE) {
3093 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3094 group_sched_out(event, cpuctx, ctx);
3096 perf_pmu_enable(ctx->pmu);
3100 * Test whether two contexts are equivalent, i.e. whether they have both been
3101 * cloned from the same version of the same context.
3103 * Equivalence is measured using a generation number in the context that is
3104 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3105 * and list_del_event().
3107 static int context_equiv(struct perf_event_context *ctx1,
3108 struct perf_event_context *ctx2)
3110 lockdep_assert_held(&ctx1->lock);
3111 lockdep_assert_held(&ctx2->lock);
3113 /* Pinning disables the swap optimization */
3114 if (ctx1->pin_count || ctx2->pin_count)
3117 /* If ctx1 is the parent of ctx2 */
3118 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3121 /* If ctx2 is the parent of ctx1 */
3122 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3126 * If ctx1 and ctx2 have the same parent; we flatten the parent
3127 * hierarchy, see perf_event_init_context().
3129 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3130 ctx1->parent_gen == ctx2->parent_gen)
3137 static void __perf_event_sync_stat(struct perf_event *event,
3138 struct perf_event *next_event)
3142 if (!event->attr.inherit_stat)
3146 * Update the event value, we cannot use perf_event_read()
3147 * because we're in the middle of a context switch and have IRQs
3148 * disabled, which upsets smp_call_function_single(), however
3149 * we know the event must be on the current CPU, therefore we
3150 * don't need to use it.
3152 if (event->state == PERF_EVENT_STATE_ACTIVE)
3153 event->pmu->read(event);
3155 perf_event_update_time(event);
3158 * In order to keep per-task stats reliable we need to flip the event
3159 * values when we flip the contexts.
3161 value = local64_read(&next_event->count);
3162 value = local64_xchg(&event->count, value);
3163 local64_set(&next_event->count, value);
3165 swap(event->total_time_enabled, next_event->total_time_enabled);
3166 swap(event->total_time_running, next_event->total_time_running);
3169 * Since we swizzled the values, update the user visible data too.
3171 perf_event_update_userpage(event);
3172 perf_event_update_userpage(next_event);
3175 static void perf_event_sync_stat(struct perf_event_context *ctx,
3176 struct perf_event_context *next_ctx)
3178 struct perf_event *event, *next_event;
3183 update_context_time(ctx);
3185 event = list_first_entry(&ctx->event_list,
3186 struct perf_event, event_entry);
3188 next_event = list_first_entry(&next_ctx->event_list,
3189 struct perf_event, event_entry);
3191 while (&event->event_entry != &ctx->event_list &&
3192 &next_event->event_entry != &next_ctx->event_list) {
3194 __perf_event_sync_stat(event, next_event);
3196 event = list_next_entry(event, event_entry);
3197 next_event = list_next_entry(next_event, event_entry);
3201 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3202 struct task_struct *next)
3204 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3205 struct perf_event_context *next_ctx;
3206 struct perf_event_context *parent, *next_parent;
3207 struct perf_cpu_context *cpuctx;
3213 cpuctx = __get_cpu_context(ctx);
3214 if (!cpuctx->task_ctx)
3218 next_ctx = next->perf_event_ctxp[ctxn];
3222 parent = rcu_dereference(ctx->parent_ctx);
3223 next_parent = rcu_dereference(next_ctx->parent_ctx);
3225 /* If neither context have a parent context; they cannot be clones. */
3226 if (!parent && !next_parent)
3229 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3231 * Looks like the two contexts are clones, so we might be
3232 * able to optimize the context switch. We lock both
3233 * contexts and check that they are clones under the
3234 * lock (including re-checking that neither has been
3235 * uncloned in the meantime). It doesn't matter which
3236 * order we take the locks because no other cpu could
3237 * be trying to lock both of these tasks.
3239 raw_spin_lock(&ctx->lock);
3240 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3241 if (context_equiv(ctx, next_ctx)) {
3242 struct pmu *pmu = ctx->pmu;
3244 WRITE_ONCE(ctx->task, next);
3245 WRITE_ONCE(next_ctx->task, task);
3248 * PMU specific parts of task perf context can require
3249 * additional synchronization. As an example of such
3250 * synchronization see implementation details of Intel
3251 * LBR call stack data profiling;
3253 if (pmu->swap_task_ctx)
3254 pmu->swap_task_ctx(ctx, next_ctx);
3256 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3259 * RCU_INIT_POINTER here is safe because we've not
3260 * modified the ctx and the above modification of
3261 * ctx->task and ctx->task_ctx_data are immaterial
3262 * since those values are always verified under
3263 * ctx->lock which we're now holding.
3265 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3266 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3270 perf_event_sync_stat(ctx, next_ctx);
3272 raw_spin_unlock(&next_ctx->lock);
3273 raw_spin_unlock(&ctx->lock);
3279 raw_spin_lock(&ctx->lock);
3280 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3281 raw_spin_unlock(&ctx->lock);
3285 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3287 void perf_sched_cb_dec(struct pmu *pmu)
3289 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3291 this_cpu_dec(perf_sched_cb_usages);
3293 if (!--cpuctx->sched_cb_usage)
3294 list_del(&cpuctx->sched_cb_entry);
3298 void perf_sched_cb_inc(struct pmu *pmu)
3300 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3302 if (!cpuctx->sched_cb_usage++)
3303 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3305 this_cpu_inc(perf_sched_cb_usages);
3309 * This function provides the context switch callback to the lower code
3310 * layer. It is invoked ONLY when the context switch callback is enabled.
3312 * This callback is relevant even to per-cpu events; for example multi event
3313 * PEBS requires this to provide PID/TID information. This requires we flush
3314 * all queued PEBS records before we context switch to a new task.
3316 static void perf_pmu_sched_task(struct task_struct *prev,
3317 struct task_struct *next,
3320 struct perf_cpu_context *cpuctx;
3326 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3327 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3329 if (WARN_ON_ONCE(!pmu->sched_task))
3332 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3333 perf_pmu_disable(pmu);
3335 pmu->sched_task(cpuctx->task_ctx, sched_in);
3337 perf_pmu_enable(pmu);
3338 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3342 static void perf_event_switch(struct task_struct *task,
3343 struct task_struct *next_prev, bool sched_in);
3345 #define for_each_task_context_nr(ctxn) \
3346 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3349 * Called from scheduler to remove the events of the current task,
3350 * with interrupts disabled.
3352 * We stop each event and update the event value in event->count.
3354 * This does not protect us against NMI, but disable()
3355 * sets the disabled bit in the control field of event _before_
3356 * accessing the event control register. If a NMI hits, then it will
3357 * not restart the event.
3359 void __perf_event_task_sched_out(struct task_struct *task,
3360 struct task_struct *next)
3364 if (__this_cpu_read(perf_sched_cb_usages))
3365 perf_pmu_sched_task(task, next, false);
3367 if (atomic_read(&nr_switch_events))
3368 perf_event_switch(task, next, false);
3370 for_each_task_context_nr(ctxn)
3371 perf_event_context_sched_out(task, ctxn, next);
3374 * if cgroup events exist on this CPU, then we need
3375 * to check if we have to switch out PMU state.
3376 * cgroup event are system-wide mode only
3378 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3379 perf_cgroup_sched_out(task, next);
3383 * Called with IRQs disabled
3385 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3386 enum event_type_t event_type)
3388 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3391 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3392 int (*func)(struct perf_event *, void *), void *data)
3394 struct perf_event **evt, *evt1, *evt2;
3397 evt1 = perf_event_groups_first(groups, -1);
3398 evt2 = perf_event_groups_first(groups, cpu);
3400 while (evt1 || evt2) {
3402 if (evt1->group_index < evt2->group_index)
3412 ret = func(*evt, data);
3416 *evt = perf_event_groups_next(*evt);
3422 struct sched_in_data {
3423 struct perf_event_context *ctx;
3424 struct perf_cpu_context *cpuctx;
3428 static int pinned_sched_in(struct perf_event *event, void *data)
3430 struct sched_in_data *sid = data;
3432 if (event->state <= PERF_EVENT_STATE_OFF)
3435 if (!event_filter_match(event))
3438 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3439 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3440 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3444 * If this pinned group hasn't been scheduled,
3445 * put it in error state.
3447 if (event->state == PERF_EVENT_STATE_INACTIVE)
3448 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3453 static int flexible_sched_in(struct perf_event *event, void *data)
3455 struct sched_in_data *sid = data;
3457 if (event->state <= PERF_EVENT_STATE_OFF)
3460 if (!event_filter_match(event))
3463 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3464 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3466 sid->can_add_hw = 0;
3467 sid->ctx->rotate_necessary = 1;
3470 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3477 ctx_pinned_sched_in(struct perf_event_context *ctx,
3478 struct perf_cpu_context *cpuctx)
3480 struct sched_in_data sid = {
3486 visit_groups_merge(&ctx->pinned_groups,
3488 pinned_sched_in, &sid);
3492 ctx_flexible_sched_in(struct perf_event_context *ctx,
3493 struct perf_cpu_context *cpuctx)
3495 struct sched_in_data sid = {
3501 visit_groups_merge(&ctx->flexible_groups,
3503 flexible_sched_in, &sid);
3507 ctx_sched_in(struct perf_event_context *ctx,
3508 struct perf_cpu_context *cpuctx,
3509 enum event_type_t event_type,
3510 struct task_struct *task)
3512 int is_active = ctx->is_active;
3515 lockdep_assert_held(&ctx->lock);
3517 if (likely(!ctx->nr_events))
3520 ctx->is_active |= (event_type | EVENT_TIME);
3523 cpuctx->task_ctx = ctx;
3525 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3528 is_active ^= ctx->is_active; /* changed bits */
3530 if (is_active & EVENT_TIME) {
3531 /* start ctx time */
3533 ctx->timestamp = now;
3534 perf_cgroup_set_timestamp(task, ctx);
3538 * First go through the list and put on any pinned groups
3539 * in order to give them the best chance of going on.
3541 if (is_active & EVENT_PINNED)
3542 ctx_pinned_sched_in(ctx, cpuctx);
3544 /* Then walk through the lower prio flexible groups */
3545 if (is_active & EVENT_FLEXIBLE)
3546 ctx_flexible_sched_in(ctx, cpuctx);
3549 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3550 enum event_type_t event_type,
3551 struct task_struct *task)
3553 struct perf_event_context *ctx = &cpuctx->ctx;
3555 ctx_sched_in(ctx, cpuctx, event_type, task);
3558 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3559 struct task_struct *task)
3561 struct perf_cpu_context *cpuctx;
3563 cpuctx = __get_cpu_context(ctx);
3564 if (cpuctx->task_ctx == ctx)
3567 perf_ctx_lock(cpuctx, ctx);
3569 * We must check ctx->nr_events while holding ctx->lock, such
3570 * that we serialize against perf_install_in_context().
3572 if (!ctx->nr_events)
3575 perf_pmu_disable(ctx->pmu);
3577 * We want to keep the following priority order:
3578 * cpu pinned (that don't need to move), task pinned,
3579 * cpu flexible, task flexible.
3581 * However, if task's ctx is not carrying any pinned
3582 * events, no need to flip the cpuctx's events around.
3584 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3585 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3586 perf_event_sched_in(cpuctx, ctx, task);
3587 perf_pmu_enable(ctx->pmu);
3590 perf_ctx_unlock(cpuctx, ctx);
3594 * Called from scheduler to add the events of the current task
3595 * with interrupts disabled.
3597 * We restore the event value and then enable it.
3599 * This does not protect us against NMI, but enable()
3600 * sets the enabled bit in the control field of event _before_
3601 * accessing the event control register. If a NMI hits, then it will
3602 * keep the event running.
3604 void __perf_event_task_sched_in(struct task_struct *prev,
3605 struct task_struct *task)
3607 struct perf_event_context *ctx;
3611 * If cgroup events exist on this CPU, then we need to check if we have
3612 * to switch in PMU state; cgroup event are system-wide mode only.
3614 * Since cgroup events are CPU events, we must schedule these in before
3615 * we schedule in the task events.
3617 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3618 perf_cgroup_sched_in(prev, task);
3620 for_each_task_context_nr(ctxn) {
3621 ctx = task->perf_event_ctxp[ctxn];
3625 perf_event_context_sched_in(ctx, task);
3628 if (atomic_read(&nr_switch_events))
3629 perf_event_switch(task, prev, true);
3631 if (__this_cpu_read(perf_sched_cb_usages))
3632 perf_pmu_sched_task(prev, task, true);
3635 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3637 u64 frequency = event->attr.sample_freq;
3638 u64 sec = NSEC_PER_SEC;
3639 u64 divisor, dividend;
3641 int count_fls, nsec_fls, frequency_fls, sec_fls;
3643 count_fls = fls64(count);
3644 nsec_fls = fls64(nsec);
3645 frequency_fls = fls64(frequency);
3649 * We got @count in @nsec, with a target of sample_freq HZ
3650 * the target period becomes:
3653 * period = -------------------
3654 * @nsec * sample_freq
3659 * Reduce accuracy by one bit such that @a and @b converge
3660 * to a similar magnitude.
3662 #define REDUCE_FLS(a, b) \
3664 if (a##_fls > b##_fls) { \
3674 * Reduce accuracy until either term fits in a u64, then proceed with
3675 * the other, so that finally we can do a u64/u64 division.
3677 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3678 REDUCE_FLS(nsec, frequency);
3679 REDUCE_FLS(sec, count);
3682 if (count_fls + sec_fls > 64) {
3683 divisor = nsec * frequency;
3685 while (count_fls + sec_fls > 64) {
3686 REDUCE_FLS(count, sec);
3690 dividend = count * sec;
3692 dividend = count * sec;
3694 while (nsec_fls + frequency_fls > 64) {
3695 REDUCE_FLS(nsec, frequency);
3699 divisor = nsec * frequency;
3705 return div64_u64(dividend, divisor);
3708 static DEFINE_PER_CPU(int, perf_throttled_count);
3709 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3711 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3713 struct hw_perf_event *hwc = &event->hw;
3714 s64 period, sample_period;
3717 period = perf_calculate_period(event, nsec, count);
3719 delta = (s64)(period - hwc->sample_period);
3720 delta = (delta + 7) / 8; /* low pass filter */
3722 sample_period = hwc->sample_period + delta;
3727 hwc->sample_period = sample_period;
3729 if (local64_read(&hwc->period_left) > 8*sample_period) {
3731 event->pmu->stop(event, PERF_EF_UPDATE);
3733 local64_set(&hwc->period_left, 0);
3736 event->pmu->start(event, PERF_EF_RELOAD);
3741 * combine freq adjustment with unthrottling to avoid two passes over the
3742 * events. At the same time, make sure, having freq events does not change
3743 * the rate of unthrottling as that would introduce bias.
3745 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3748 struct perf_event *event;
3749 struct hw_perf_event *hwc;
3750 u64 now, period = TICK_NSEC;
3754 * only need to iterate over all events iff:
3755 * - context have events in frequency mode (needs freq adjust)
3756 * - there are events to unthrottle on this cpu
3758 if (!(ctx->nr_freq || needs_unthr))
3761 raw_spin_lock(&ctx->lock);
3762 perf_pmu_disable(ctx->pmu);
3764 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3765 if (event->state != PERF_EVENT_STATE_ACTIVE)
3768 if (!event_filter_match(event))
3771 perf_pmu_disable(event->pmu);
3775 if (hwc->interrupts == MAX_INTERRUPTS) {
3776 hwc->interrupts = 0;
3777 perf_log_throttle(event, 1);
3778 event->pmu->start(event, 0);
3781 if (!event->attr.freq || !event->attr.sample_freq)
3785 * stop the event and update event->count
3787 event->pmu->stop(event, PERF_EF_UPDATE);
3789 now = local64_read(&event->count);
3790 delta = now - hwc->freq_count_stamp;
3791 hwc->freq_count_stamp = now;
3795 * reload only if value has changed
3796 * we have stopped the event so tell that
3797 * to perf_adjust_period() to avoid stopping it
3801 perf_adjust_period(event, period, delta, false);
3803 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3805 perf_pmu_enable(event->pmu);
3808 perf_pmu_enable(ctx->pmu);
3809 raw_spin_unlock(&ctx->lock);
3813 * Move @event to the tail of the @ctx's elegible events.
3815 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3818 * Rotate the first entry last of non-pinned groups. Rotation might be
3819 * disabled by the inheritance code.
3821 if (ctx->rotate_disable)
3824 perf_event_groups_delete(&ctx->flexible_groups, event);
3825 perf_event_groups_insert(&ctx->flexible_groups, event);
3828 /* pick an event from the flexible_groups to rotate */
3829 static inline struct perf_event *
3830 ctx_event_to_rotate(struct perf_event_context *ctx)
3832 struct perf_event *event;
3834 /* pick the first active flexible event */
3835 event = list_first_entry_or_null(&ctx->flexible_active,
3836 struct perf_event, active_list);
3838 /* if no active flexible event, pick the first event */
3840 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3841 typeof(*event), group_node);
3847 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3849 struct perf_event *cpu_event = NULL, *task_event = NULL;
3850 struct perf_event_context *task_ctx = NULL;
3851 int cpu_rotate, task_rotate;
3854 * Since we run this from IRQ context, nobody can install new
3855 * events, thus the event count values are stable.
3858 cpu_rotate = cpuctx->ctx.rotate_necessary;
3859 task_ctx = cpuctx->task_ctx;
3860 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3862 if (!(cpu_rotate || task_rotate))
3865 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3866 perf_pmu_disable(cpuctx->ctx.pmu);
3869 task_event = ctx_event_to_rotate(task_ctx);
3871 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3874 * As per the order given at ctx_resched() first 'pop' task flexible
3875 * and then, if needed CPU flexible.
3877 if (task_event || (task_ctx && cpu_event))
3878 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3880 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3883 rotate_ctx(task_ctx, task_event);
3885 rotate_ctx(&cpuctx->ctx, cpu_event);
3887 perf_event_sched_in(cpuctx, task_ctx, current);
3889 perf_pmu_enable(cpuctx->ctx.pmu);
3890 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3895 void perf_event_task_tick(void)
3897 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3898 struct perf_event_context *ctx, *tmp;
3901 lockdep_assert_irqs_disabled();
3903 __this_cpu_inc(perf_throttled_seq);
3904 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3905 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3907 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3908 perf_adjust_freq_unthr_context(ctx, throttled);
3911 static int event_enable_on_exec(struct perf_event *event,
3912 struct perf_event_context *ctx)
3914 if (!event->attr.enable_on_exec)
3917 event->attr.enable_on_exec = 0;
3918 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3921 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3927 * Enable all of a task's events that have been marked enable-on-exec.
3928 * This expects task == current.
3930 static void perf_event_enable_on_exec(int ctxn)
3932 struct perf_event_context *ctx, *clone_ctx = NULL;
3933 enum event_type_t event_type = 0;
3934 struct perf_cpu_context *cpuctx;
3935 struct perf_event *event;
3936 unsigned long flags;
3939 local_irq_save(flags);
3940 ctx = current->perf_event_ctxp[ctxn];
3941 if (!ctx || !ctx->nr_events)
3944 cpuctx = __get_cpu_context(ctx);
3945 perf_ctx_lock(cpuctx, ctx);
3946 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3947 list_for_each_entry(event, &ctx->event_list, event_entry) {
3948 enabled |= event_enable_on_exec(event, ctx);
3949 event_type |= get_event_type(event);
3953 * Unclone and reschedule this context if we enabled any event.
3956 clone_ctx = unclone_ctx(ctx);
3957 ctx_resched(cpuctx, ctx, event_type);
3959 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3961 perf_ctx_unlock(cpuctx, ctx);
3964 local_irq_restore(flags);
3970 struct perf_read_data {
3971 struct perf_event *event;
3976 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3978 u16 local_pkg, event_pkg;
3980 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3981 int local_cpu = smp_processor_id();
3983 event_pkg = topology_physical_package_id(event_cpu);
3984 local_pkg = topology_physical_package_id(local_cpu);
3986 if (event_pkg == local_pkg)
3994 * Cross CPU call to read the hardware event
3996 static void __perf_event_read(void *info)
3998 struct perf_read_data *data = info;
3999 struct perf_event *sub, *event = data->event;
4000 struct perf_event_context *ctx = event->ctx;
4001 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4002 struct pmu *pmu = event->pmu;
4005 * If this is a task context, we need to check whether it is
4006 * the current task context of this cpu. If not it has been
4007 * scheduled out before the smp call arrived. In that case
4008 * event->count would have been updated to a recent sample
4009 * when the event was scheduled out.
4011 if (ctx->task && cpuctx->task_ctx != ctx)
4014 raw_spin_lock(&ctx->lock);
4015 if (ctx->is_active & EVENT_TIME) {
4016 update_context_time(ctx);
4017 update_cgrp_time_from_event(event);
4020 perf_event_update_time(event);
4022 perf_event_update_sibling_time(event);
4024 if (event->state != PERF_EVENT_STATE_ACTIVE)
4033 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4037 for_each_sibling_event(sub, event) {
4038 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4040 * Use sibling's PMU rather than @event's since
4041 * sibling could be on different (eg: software) PMU.
4043 sub->pmu->read(sub);
4047 data->ret = pmu->commit_txn(pmu);
4050 raw_spin_unlock(&ctx->lock);
4053 static inline u64 perf_event_count(struct perf_event *event)
4055 return local64_read(&event->count) + atomic64_read(&event->child_count);
4059 * NMI-safe method to read a local event, that is an event that
4061 * - either for the current task, or for this CPU
4062 * - does not have inherit set, for inherited task events
4063 * will not be local and we cannot read them atomically
4064 * - must not have a pmu::count method
4066 int perf_event_read_local(struct perf_event *event, u64 *value,
4067 u64 *enabled, u64 *running)
4069 unsigned long flags;
4073 * Disabling interrupts avoids all counter scheduling (context
4074 * switches, timer based rotation and IPIs).
4076 local_irq_save(flags);
4079 * It must not be an event with inherit set, we cannot read
4080 * all child counters from atomic context.
4082 if (event->attr.inherit) {
4087 /* If this is a per-task event, it must be for current */
4088 if ((event->attach_state & PERF_ATTACH_TASK) &&
4089 event->hw.target != current) {
4094 /* If this is a per-CPU event, it must be for this CPU */
4095 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4096 event->cpu != smp_processor_id()) {
4101 /* If this is a pinned event it must be running on this CPU */
4102 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4108 * If the event is currently on this CPU, its either a per-task event,
4109 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4112 if (event->oncpu == smp_processor_id())
4113 event->pmu->read(event);
4115 *value = local64_read(&event->count);
4116 if (enabled || running) {
4117 u64 now = event->shadow_ctx_time + perf_clock();
4118 u64 __enabled, __running;
4120 __perf_update_times(event, now, &__enabled, &__running);
4122 *enabled = __enabled;
4124 *running = __running;
4127 local_irq_restore(flags);
4132 static int perf_event_read(struct perf_event *event, bool group)
4134 enum perf_event_state state = READ_ONCE(event->state);
4135 int event_cpu, ret = 0;
4138 * If event is enabled and currently active on a CPU, update the
4139 * value in the event structure:
4142 if (state == PERF_EVENT_STATE_ACTIVE) {
4143 struct perf_read_data data;
4146 * Orders the ->state and ->oncpu loads such that if we see
4147 * ACTIVE we must also see the right ->oncpu.
4149 * Matches the smp_wmb() from event_sched_in().
4153 event_cpu = READ_ONCE(event->oncpu);
4154 if ((unsigned)event_cpu >= nr_cpu_ids)
4157 data = (struct perf_read_data){
4164 event_cpu = __perf_event_read_cpu(event, event_cpu);
4167 * Purposely ignore the smp_call_function_single() return
4170 * If event_cpu isn't a valid CPU it means the event got
4171 * scheduled out and that will have updated the event count.
4173 * Therefore, either way, we'll have an up-to-date event count
4176 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4180 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4181 struct perf_event_context *ctx = event->ctx;
4182 unsigned long flags;
4184 raw_spin_lock_irqsave(&ctx->lock, flags);
4185 state = event->state;
4186 if (state != PERF_EVENT_STATE_INACTIVE) {
4187 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4192 * May read while context is not active (e.g., thread is
4193 * blocked), in that case we cannot update context time
4195 if (ctx->is_active & EVENT_TIME) {
4196 update_context_time(ctx);
4197 update_cgrp_time_from_event(event);
4200 perf_event_update_time(event);
4202 perf_event_update_sibling_time(event);
4203 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4210 * Initialize the perf_event context in a task_struct:
4212 static void __perf_event_init_context(struct perf_event_context *ctx)
4214 raw_spin_lock_init(&ctx->lock);
4215 mutex_init(&ctx->mutex);
4216 INIT_LIST_HEAD(&ctx->active_ctx_list);
4217 perf_event_groups_init(&ctx->pinned_groups);
4218 perf_event_groups_init(&ctx->flexible_groups);
4219 INIT_LIST_HEAD(&ctx->event_list);
4220 INIT_LIST_HEAD(&ctx->pinned_active);
4221 INIT_LIST_HEAD(&ctx->flexible_active);
4222 refcount_set(&ctx->refcount, 1);
4225 static struct perf_event_context *
4226 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4228 struct perf_event_context *ctx;
4230 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4234 __perf_event_init_context(ctx);
4236 ctx->task = get_task_struct(task);
4242 static struct task_struct *
4243 find_lively_task_by_vpid(pid_t vpid)
4245 struct task_struct *task;
4251 task = find_task_by_vpid(vpid);
4253 get_task_struct(task);
4257 return ERR_PTR(-ESRCH);
4263 * Returns a matching context with refcount and pincount.
4265 static struct perf_event_context *
4266 find_get_context(struct pmu *pmu, struct task_struct *task,
4267 struct perf_event *event)
4269 struct perf_event_context *ctx, *clone_ctx = NULL;
4270 struct perf_cpu_context *cpuctx;
4271 void *task_ctx_data = NULL;
4272 unsigned long flags;
4274 int cpu = event->cpu;
4277 /* Must be root to operate on a CPU event: */
4278 err = perf_allow_cpu(&event->attr);
4280 return ERR_PTR(err);
4282 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4291 ctxn = pmu->task_ctx_nr;
4295 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4296 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4297 if (!task_ctx_data) {
4304 ctx = perf_lock_task_context(task, ctxn, &flags);
4306 clone_ctx = unclone_ctx(ctx);
4309 if (task_ctx_data && !ctx->task_ctx_data) {
4310 ctx->task_ctx_data = task_ctx_data;
4311 task_ctx_data = NULL;
4313 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4318 ctx = alloc_perf_context(pmu, task);
4323 if (task_ctx_data) {
4324 ctx->task_ctx_data = task_ctx_data;
4325 task_ctx_data = NULL;
4329 mutex_lock(&task->perf_event_mutex);
4331 * If it has already passed perf_event_exit_task().
4332 * we must see PF_EXITING, it takes this mutex too.
4334 if (task->flags & PF_EXITING)
4336 else if (task->perf_event_ctxp[ctxn])
4341 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4343 mutex_unlock(&task->perf_event_mutex);
4345 if (unlikely(err)) {
4354 kfree(task_ctx_data);
4358 kfree(task_ctx_data);
4359 return ERR_PTR(err);
4362 static void perf_event_free_filter(struct perf_event *event);
4363 static void perf_event_free_bpf_prog(struct perf_event *event);
4365 static void free_event_rcu(struct rcu_head *head)
4367 struct perf_event *event;
4369 event = container_of(head, struct perf_event, rcu_head);
4371 put_pid_ns(event->ns);
4372 perf_event_free_filter(event);
4376 static void ring_buffer_attach(struct perf_event *event,
4377 struct perf_buffer *rb);
4379 static void detach_sb_event(struct perf_event *event)
4381 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4383 raw_spin_lock(&pel->lock);
4384 list_del_rcu(&event->sb_list);
4385 raw_spin_unlock(&pel->lock);
4388 static bool is_sb_event(struct perf_event *event)
4390 struct perf_event_attr *attr = &event->attr;
4395 if (event->attach_state & PERF_ATTACH_TASK)
4398 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4399 attr->comm || attr->comm_exec ||
4400 attr->task || attr->ksymbol ||
4401 attr->context_switch ||
4407 static void unaccount_pmu_sb_event(struct perf_event *event)
4409 if (is_sb_event(event))
4410 detach_sb_event(event);
4413 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4418 if (is_cgroup_event(event))
4419 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4422 #ifdef CONFIG_NO_HZ_FULL
4423 static DEFINE_SPINLOCK(nr_freq_lock);
4426 static void unaccount_freq_event_nohz(void)
4428 #ifdef CONFIG_NO_HZ_FULL
4429 spin_lock(&nr_freq_lock);
4430 if (atomic_dec_and_test(&nr_freq_events))
4431 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4432 spin_unlock(&nr_freq_lock);
4436 static void unaccount_freq_event(void)
4438 if (tick_nohz_full_enabled())
4439 unaccount_freq_event_nohz();
4441 atomic_dec(&nr_freq_events);
4444 static void unaccount_event(struct perf_event *event)
4451 if (event->attach_state & PERF_ATTACH_TASK)
4453 if (event->attr.mmap || event->attr.mmap_data)
4454 atomic_dec(&nr_mmap_events);
4455 if (event->attr.comm)
4456 atomic_dec(&nr_comm_events);
4457 if (event->attr.namespaces)
4458 atomic_dec(&nr_namespaces_events);
4459 if (event->attr.task)
4460 atomic_dec(&nr_task_events);
4461 if (event->attr.freq)
4462 unaccount_freq_event();
4463 if (event->attr.context_switch) {
4465 atomic_dec(&nr_switch_events);
4467 if (is_cgroup_event(event))
4469 if (has_branch_stack(event))
4471 if (event->attr.ksymbol)
4472 atomic_dec(&nr_ksymbol_events);
4473 if (event->attr.bpf_event)
4474 atomic_dec(&nr_bpf_events);
4477 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4478 schedule_delayed_work(&perf_sched_work, HZ);
4481 unaccount_event_cpu(event, event->cpu);
4483 unaccount_pmu_sb_event(event);
4486 static void perf_sched_delayed(struct work_struct *work)
4488 mutex_lock(&perf_sched_mutex);
4489 if (atomic_dec_and_test(&perf_sched_count))
4490 static_branch_disable(&perf_sched_events);
4491 mutex_unlock(&perf_sched_mutex);
4495 * The following implement mutual exclusion of events on "exclusive" pmus
4496 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4497 * at a time, so we disallow creating events that might conflict, namely:
4499 * 1) cpu-wide events in the presence of per-task events,
4500 * 2) per-task events in the presence of cpu-wide events,
4501 * 3) two matching events on the same context.
4503 * The former two cases are handled in the allocation path (perf_event_alloc(),
4504 * _free_event()), the latter -- before the first perf_install_in_context().
4506 static int exclusive_event_init(struct perf_event *event)
4508 struct pmu *pmu = event->pmu;
4510 if (!is_exclusive_pmu(pmu))
4514 * Prevent co-existence of per-task and cpu-wide events on the
4515 * same exclusive pmu.
4517 * Negative pmu::exclusive_cnt means there are cpu-wide
4518 * events on this "exclusive" pmu, positive means there are
4521 * Since this is called in perf_event_alloc() path, event::ctx
4522 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4523 * to mean "per-task event", because unlike other attach states it
4524 * never gets cleared.
4526 if (event->attach_state & PERF_ATTACH_TASK) {
4527 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4530 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4537 static void exclusive_event_destroy(struct perf_event *event)
4539 struct pmu *pmu = event->pmu;
4541 if (!is_exclusive_pmu(pmu))
4544 /* see comment in exclusive_event_init() */
4545 if (event->attach_state & PERF_ATTACH_TASK)
4546 atomic_dec(&pmu->exclusive_cnt);
4548 atomic_inc(&pmu->exclusive_cnt);
4551 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4553 if ((e1->pmu == e2->pmu) &&
4554 (e1->cpu == e2->cpu ||
4561 static bool exclusive_event_installable(struct perf_event *event,
4562 struct perf_event_context *ctx)
4564 struct perf_event *iter_event;
4565 struct pmu *pmu = event->pmu;
4567 lockdep_assert_held(&ctx->mutex);
4569 if (!is_exclusive_pmu(pmu))
4572 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4573 if (exclusive_event_match(iter_event, event))
4580 static void perf_addr_filters_splice(struct perf_event *event,
4581 struct list_head *head);
4583 static void _free_event(struct perf_event *event)
4585 irq_work_sync(&event->pending);
4587 unaccount_event(event);
4589 security_perf_event_free(event);
4593 * Can happen when we close an event with re-directed output.
4595 * Since we have a 0 refcount, perf_mmap_close() will skip
4596 * over us; possibly making our ring_buffer_put() the last.
4598 mutex_lock(&event->mmap_mutex);
4599 ring_buffer_attach(event, NULL);
4600 mutex_unlock(&event->mmap_mutex);
4603 if (is_cgroup_event(event))
4604 perf_detach_cgroup(event);
4606 if (!event->parent) {
4607 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4608 put_callchain_buffers();
4611 perf_event_free_bpf_prog(event);
4612 perf_addr_filters_splice(event, NULL);
4613 kfree(event->addr_filter_ranges);
4616 event->destroy(event);
4619 * Must be after ->destroy(), due to uprobe_perf_close() using
4622 if (event->hw.target)
4623 put_task_struct(event->hw.target);
4626 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4627 * all task references must be cleaned up.
4630 put_ctx(event->ctx);
4632 exclusive_event_destroy(event);
4633 module_put(event->pmu->module);
4635 call_rcu(&event->rcu_head, free_event_rcu);
4639 * Used to free events which have a known refcount of 1, such as in error paths
4640 * where the event isn't exposed yet and inherited events.
4642 static void free_event(struct perf_event *event)
4644 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4645 "unexpected event refcount: %ld; ptr=%p\n",
4646 atomic_long_read(&event->refcount), event)) {
4647 /* leak to avoid use-after-free */
4655 * Remove user event from the owner task.
4657 static void perf_remove_from_owner(struct perf_event *event)
4659 struct task_struct *owner;
4663 * Matches the smp_store_release() in perf_event_exit_task(). If we
4664 * observe !owner it means the list deletion is complete and we can
4665 * indeed free this event, otherwise we need to serialize on
4666 * owner->perf_event_mutex.
4668 owner = READ_ONCE(event->owner);
4671 * Since delayed_put_task_struct() also drops the last
4672 * task reference we can safely take a new reference
4673 * while holding the rcu_read_lock().
4675 get_task_struct(owner);
4681 * If we're here through perf_event_exit_task() we're already
4682 * holding ctx->mutex which would be an inversion wrt. the
4683 * normal lock order.
4685 * However we can safely take this lock because its the child
4688 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4691 * We have to re-check the event->owner field, if it is cleared
4692 * we raced with perf_event_exit_task(), acquiring the mutex
4693 * ensured they're done, and we can proceed with freeing the
4697 list_del_init(&event->owner_entry);
4698 smp_store_release(&event->owner, NULL);
4700 mutex_unlock(&owner->perf_event_mutex);
4701 put_task_struct(owner);
4705 static void put_event(struct perf_event *event)
4707 if (!atomic_long_dec_and_test(&event->refcount))
4714 * Kill an event dead; while event:refcount will preserve the event
4715 * object, it will not preserve its functionality. Once the last 'user'
4716 * gives up the object, we'll destroy the thing.
4718 int perf_event_release_kernel(struct perf_event *event)
4720 struct perf_event_context *ctx = event->ctx;
4721 struct perf_event *child, *tmp;
4722 LIST_HEAD(free_list);
4725 * If we got here through err_file: fput(event_file); we will not have
4726 * attached to a context yet.
4729 WARN_ON_ONCE(event->attach_state &
4730 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4734 if (!is_kernel_event(event))
4735 perf_remove_from_owner(event);
4737 ctx = perf_event_ctx_lock(event);
4738 WARN_ON_ONCE(ctx->parent_ctx);
4739 perf_remove_from_context(event, DETACH_GROUP);
4741 raw_spin_lock_irq(&ctx->lock);
4743 * Mark this event as STATE_DEAD, there is no external reference to it
4746 * Anybody acquiring event->child_mutex after the below loop _must_
4747 * also see this, most importantly inherit_event() which will avoid
4748 * placing more children on the list.
4750 * Thus this guarantees that we will in fact observe and kill _ALL_
4753 event->state = PERF_EVENT_STATE_DEAD;
4754 raw_spin_unlock_irq(&ctx->lock);
4756 perf_event_ctx_unlock(event, ctx);
4759 mutex_lock(&event->child_mutex);
4760 list_for_each_entry(child, &event->child_list, child_list) {
4763 * Cannot change, child events are not migrated, see the
4764 * comment with perf_event_ctx_lock_nested().
4766 ctx = READ_ONCE(child->ctx);
4768 * Since child_mutex nests inside ctx::mutex, we must jump
4769 * through hoops. We start by grabbing a reference on the ctx.
4771 * Since the event cannot get freed while we hold the
4772 * child_mutex, the context must also exist and have a !0
4778 * Now that we have a ctx ref, we can drop child_mutex, and
4779 * acquire ctx::mutex without fear of it going away. Then we
4780 * can re-acquire child_mutex.
4782 mutex_unlock(&event->child_mutex);
4783 mutex_lock(&ctx->mutex);
4784 mutex_lock(&event->child_mutex);
4787 * Now that we hold ctx::mutex and child_mutex, revalidate our
4788 * state, if child is still the first entry, it didn't get freed
4789 * and we can continue doing so.
4791 tmp = list_first_entry_or_null(&event->child_list,
4792 struct perf_event, child_list);
4794 perf_remove_from_context(child, DETACH_GROUP);
4795 list_move(&child->child_list, &free_list);
4797 * This matches the refcount bump in inherit_event();
4798 * this can't be the last reference.
4803 mutex_unlock(&event->child_mutex);
4804 mutex_unlock(&ctx->mutex);
4808 mutex_unlock(&event->child_mutex);
4810 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4811 void *var = &child->ctx->refcount;
4813 list_del(&child->child_list);
4817 * Wake any perf_event_free_task() waiting for this event to be
4820 smp_mb(); /* pairs with wait_var_event() */
4825 put_event(event); /* Must be the 'last' reference */
4828 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4831 * Called when the last reference to the file is gone.
4833 static int perf_release(struct inode *inode, struct file *file)
4835 perf_event_release_kernel(file->private_data);
4839 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4841 struct perf_event *child;
4847 mutex_lock(&event->child_mutex);
4849 (void)perf_event_read(event, false);
4850 total += perf_event_count(event);
4852 *enabled += event->total_time_enabled +
4853 atomic64_read(&event->child_total_time_enabled);
4854 *running += event->total_time_running +
4855 atomic64_read(&event->child_total_time_running);
4857 list_for_each_entry(child, &event->child_list, child_list) {
4858 (void)perf_event_read(child, false);
4859 total += perf_event_count(child);
4860 *enabled += child->total_time_enabled;
4861 *running += child->total_time_running;
4863 mutex_unlock(&event->child_mutex);
4868 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4870 struct perf_event_context *ctx;
4873 ctx = perf_event_ctx_lock(event);
4874 count = __perf_event_read_value(event, enabled, running);
4875 perf_event_ctx_unlock(event, ctx);
4879 EXPORT_SYMBOL_GPL(perf_event_read_value);
4881 static int __perf_read_group_add(struct perf_event *leader,
4882 u64 read_format, u64 *values)
4884 struct perf_event_context *ctx = leader->ctx;
4885 struct perf_event *sub;
4886 unsigned long flags;
4887 int n = 1; /* skip @nr */
4890 ret = perf_event_read(leader, true);
4894 raw_spin_lock_irqsave(&ctx->lock, flags);
4897 * Since we co-schedule groups, {enabled,running} times of siblings
4898 * will be identical to those of the leader, so we only publish one
4901 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4902 values[n++] += leader->total_time_enabled +
4903 atomic64_read(&leader->child_total_time_enabled);
4906 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4907 values[n++] += leader->total_time_running +
4908 atomic64_read(&leader->child_total_time_running);
4912 * Write {count,id} tuples for every sibling.
4914 values[n++] += perf_event_count(leader);
4915 if (read_format & PERF_FORMAT_ID)
4916 values[n++] = primary_event_id(leader);
4918 for_each_sibling_event(sub, leader) {
4919 values[n++] += perf_event_count(sub);
4920 if (read_format & PERF_FORMAT_ID)
4921 values[n++] = primary_event_id(sub);
4924 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4928 static int perf_read_group(struct perf_event *event,
4929 u64 read_format, char __user *buf)
4931 struct perf_event *leader = event->group_leader, *child;
4932 struct perf_event_context *ctx = leader->ctx;
4936 lockdep_assert_held(&ctx->mutex);
4938 values = kzalloc(event->read_size, GFP_KERNEL);
4942 values[0] = 1 + leader->nr_siblings;
4945 * By locking the child_mutex of the leader we effectively
4946 * lock the child list of all siblings.. XXX explain how.
4948 mutex_lock(&leader->child_mutex);
4950 ret = __perf_read_group_add(leader, read_format, values);
4954 list_for_each_entry(child, &leader->child_list, child_list) {
4955 ret = __perf_read_group_add(child, read_format, values);
4960 mutex_unlock(&leader->child_mutex);
4962 ret = event->read_size;
4963 if (copy_to_user(buf, values, event->read_size))
4968 mutex_unlock(&leader->child_mutex);
4974 static int perf_read_one(struct perf_event *event,
4975 u64 read_format, char __user *buf)
4977 u64 enabled, running;
4981 values[n++] = __perf_event_read_value(event, &enabled, &running);
4982 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4983 values[n++] = enabled;
4984 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4985 values[n++] = running;
4986 if (read_format & PERF_FORMAT_ID)
4987 values[n++] = primary_event_id(event);
4989 if (copy_to_user(buf, values, n * sizeof(u64)))
4992 return n * sizeof(u64);
4995 static bool is_event_hup(struct perf_event *event)
4999 if (event->state > PERF_EVENT_STATE_EXIT)
5002 mutex_lock(&event->child_mutex);
5003 no_children = list_empty(&event->child_list);
5004 mutex_unlock(&event->child_mutex);
5009 * Read the performance event - simple non blocking version for now
5012 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5014 u64 read_format = event->attr.read_format;
5018 * Return end-of-file for a read on an event that is in
5019 * error state (i.e. because it was pinned but it couldn't be
5020 * scheduled on to the CPU at some point).
5022 if (event->state == PERF_EVENT_STATE_ERROR)
5025 if (count < event->read_size)
5028 WARN_ON_ONCE(event->ctx->parent_ctx);
5029 if (read_format & PERF_FORMAT_GROUP)
5030 ret = perf_read_group(event, read_format, buf);
5032 ret = perf_read_one(event, read_format, buf);
5038 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5040 struct perf_event *event = file->private_data;
5041 struct perf_event_context *ctx;
5044 ret = security_perf_event_read(event);
5048 ctx = perf_event_ctx_lock(event);
5049 ret = __perf_read(event, buf, count);
5050 perf_event_ctx_unlock(event, ctx);
5055 static __poll_t perf_poll(struct file *file, poll_table *wait)
5057 struct perf_event *event = file->private_data;
5058 struct perf_buffer *rb;
5059 __poll_t events = EPOLLHUP;
5061 poll_wait(file, &event->waitq, wait);
5063 if (is_event_hup(event))
5067 * Pin the event->rb by taking event->mmap_mutex; otherwise
5068 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5070 mutex_lock(&event->mmap_mutex);
5073 events = atomic_xchg(&rb->poll, 0);
5074 mutex_unlock(&event->mmap_mutex);
5078 static void _perf_event_reset(struct perf_event *event)
5080 (void)perf_event_read(event, false);
5081 local64_set(&event->count, 0);
5082 perf_event_update_userpage(event);
5085 /* Assume it's not an event with inherit set. */
5086 u64 perf_event_pause(struct perf_event *event, bool reset)
5088 struct perf_event_context *ctx;
5091 ctx = perf_event_ctx_lock(event);
5092 WARN_ON_ONCE(event->attr.inherit);
5093 _perf_event_disable(event);
5094 count = local64_read(&event->count);
5096 local64_set(&event->count, 0);
5097 perf_event_ctx_unlock(event, ctx);
5101 EXPORT_SYMBOL_GPL(perf_event_pause);
5104 * Holding the top-level event's child_mutex means that any
5105 * descendant process that has inherited this event will block
5106 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5107 * task existence requirements of perf_event_enable/disable.
5109 static void perf_event_for_each_child(struct perf_event *event,
5110 void (*func)(struct perf_event *))
5112 struct perf_event *child;
5114 WARN_ON_ONCE(event->ctx->parent_ctx);
5116 mutex_lock(&event->child_mutex);
5118 list_for_each_entry(child, &event->child_list, child_list)
5120 mutex_unlock(&event->child_mutex);
5123 static void perf_event_for_each(struct perf_event *event,
5124 void (*func)(struct perf_event *))
5126 struct perf_event_context *ctx = event->ctx;
5127 struct perf_event *sibling;
5129 lockdep_assert_held(&ctx->mutex);
5131 event = event->group_leader;
5133 perf_event_for_each_child(event, func);
5134 for_each_sibling_event(sibling, event)
5135 perf_event_for_each_child(sibling, func);
5138 static void __perf_event_period(struct perf_event *event,
5139 struct perf_cpu_context *cpuctx,
5140 struct perf_event_context *ctx,
5143 u64 value = *((u64 *)info);
5146 if (event->attr.freq) {
5147 event->attr.sample_freq = value;
5149 event->attr.sample_period = value;
5150 event->hw.sample_period = value;
5153 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5155 perf_pmu_disable(ctx->pmu);
5157 * We could be throttled; unthrottle now to avoid the tick
5158 * trying to unthrottle while we already re-started the event.
5160 if (event->hw.interrupts == MAX_INTERRUPTS) {
5161 event->hw.interrupts = 0;
5162 perf_log_throttle(event, 1);
5164 event->pmu->stop(event, PERF_EF_UPDATE);
5167 local64_set(&event->hw.period_left, 0);
5170 event->pmu->start(event, PERF_EF_RELOAD);
5171 perf_pmu_enable(ctx->pmu);
5175 static int perf_event_check_period(struct perf_event *event, u64 value)
5177 return event->pmu->check_period(event, value);
5180 static int _perf_event_period(struct perf_event *event, u64 value)
5182 if (!is_sampling_event(event))
5188 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5191 if (perf_event_check_period(event, value))
5194 if (!event->attr.freq && (value & (1ULL << 63)))
5197 event_function_call(event, __perf_event_period, &value);
5202 int perf_event_period(struct perf_event *event, u64 value)
5204 struct perf_event_context *ctx;
5207 ctx = perf_event_ctx_lock(event);
5208 ret = _perf_event_period(event, value);
5209 perf_event_ctx_unlock(event, ctx);
5213 EXPORT_SYMBOL_GPL(perf_event_period);
5215 static const struct file_operations perf_fops;
5217 static inline int perf_fget_light(int fd, struct fd *p)
5219 struct fd f = fdget(fd);
5223 if (f.file->f_op != &perf_fops) {
5231 static int perf_event_set_output(struct perf_event *event,
5232 struct perf_event *output_event);
5233 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5234 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5235 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5236 struct perf_event_attr *attr);
5238 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5240 void (*func)(struct perf_event *);
5244 case PERF_EVENT_IOC_ENABLE:
5245 func = _perf_event_enable;
5247 case PERF_EVENT_IOC_DISABLE:
5248 func = _perf_event_disable;
5250 case PERF_EVENT_IOC_RESET:
5251 func = _perf_event_reset;
5254 case PERF_EVENT_IOC_REFRESH:
5255 return _perf_event_refresh(event, arg);
5257 case PERF_EVENT_IOC_PERIOD:
5261 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5264 return _perf_event_period(event, value);
5266 case PERF_EVENT_IOC_ID:
5268 u64 id = primary_event_id(event);
5270 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5275 case PERF_EVENT_IOC_SET_OUTPUT:
5279 struct perf_event *output_event;
5281 ret = perf_fget_light(arg, &output);
5284 output_event = output.file->private_data;
5285 ret = perf_event_set_output(event, output_event);
5288 ret = perf_event_set_output(event, NULL);
5293 case PERF_EVENT_IOC_SET_FILTER:
5294 return perf_event_set_filter(event, (void __user *)arg);
5296 case PERF_EVENT_IOC_SET_BPF:
5297 return perf_event_set_bpf_prog(event, arg);
5299 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5300 struct perf_buffer *rb;
5303 rb = rcu_dereference(event->rb);
5304 if (!rb || !rb->nr_pages) {
5308 rb_toggle_paused(rb, !!arg);
5313 case PERF_EVENT_IOC_QUERY_BPF:
5314 return perf_event_query_prog_array(event, (void __user *)arg);
5316 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5317 struct perf_event_attr new_attr;
5318 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5324 return perf_event_modify_attr(event, &new_attr);
5330 if (flags & PERF_IOC_FLAG_GROUP)
5331 perf_event_for_each(event, func);
5333 perf_event_for_each_child(event, func);
5338 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5340 struct perf_event *event = file->private_data;
5341 struct perf_event_context *ctx;
5344 /* Treat ioctl like writes as it is likely a mutating operation. */
5345 ret = security_perf_event_write(event);
5349 ctx = perf_event_ctx_lock(event);
5350 ret = _perf_ioctl(event, cmd, arg);
5351 perf_event_ctx_unlock(event, ctx);
5356 #ifdef CONFIG_COMPAT
5357 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5360 switch (_IOC_NR(cmd)) {
5361 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5362 case _IOC_NR(PERF_EVENT_IOC_ID):
5363 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5364 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5365 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5366 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5367 cmd &= ~IOCSIZE_MASK;
5368 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5372 return perf_ioctl(file, cmd, arg);
5375 # define perf_compat_ioctl NULL
5378 int perf_event_task_enable(void)
5380 struct perf_event_context *ctx;
5381 struct perf_event *event;
5383 mutex_lock(¤t->perf_event_mutex);
5384 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5385 ctx = perf_event_ctx_lock(event);
5386 perf_event_for_each_child(event, _perf_event_enable);
5387 perf_event_ctx_unlock(event, ctx);
5389 mutex_unlock(¤t->perf_event_mutex);
5394 int perf_event_task_disable(void)
5396 struct perf_event_context *ctx;
5397 struct perf_event *event;
5399 mutex_lock(¤t->perf_event_mutex);
5400 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5401 ctx = perf_event_ctx_lock(event);
5402 perf_event_for_each_child(event, _perf_event_disable);
5403 perf_event_ctx_unlock(event, ctx);
5405 mutex_unlock(¤t->perf_event_mutex);
5410 static int perf_event_index(struct perf_event *event)
5412 if (event->hw.state & PERF_HES_STOPPED)
5415 if (event->state != PERF_EVENT_STATE_ACTIVE)
5418 return event->pmu->event_idx(event);
5421 static void calc_timer_values(struct perf_event *event,
5428 *now = perf_clock();
5429 ctx_time = event->shadow_ctx_time + *now;
5430 __perf_update_times(event, ctx_time, enabled, running);
5433 static void perf_event_init_userpage(struct perf_event *event)
5435 struct perf_event_mmap_page *userpg;
5436 struct perf_buffer *rb;
5439 rb = rcu_dereference(event->rb);
5443 userpg = rb->user_page;
5445 /* Allow new userspace to detect that bit 0 is deprecated */
5446 userpg->cap_bit0_is_deprecated = 1;
5447 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5448 userpg->data_offset = PAGE_SIZE;
5449 userpg->data_size = perf_data_size(rb);
5455 void __weak arch_perf_update_userpage(
5456 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5461 * Callers need to ensure there can be no nesting of this function, otherwise
5462 * the seqlock logic goes bad. We can not serialize this because the arch
5463 * code calls this from NMI context.
5465 void perf_event_update_userpage(struct perf_event *event)
5467 struct perf_event_mmap_page *userpg;
5468 struct perf_buffer *rb;
5469 u64 enabled, running, now;
5472 rb = rcu_dereference(event->rb);
5477 * compute total_time_enabled, total_time_running
5478 * based on snapshot values taken when the event
5479 * was last scheduled in.
5481 * we cannot simply called update_context_time()
5482 * because of locking issue as we can be called in
5485 calc_timer_values(event, &now, &enabled, &running);
5487 userpg = rb->user_page;
5489 * Disable preemption to guarantee consistent time stamps are stored to
5495 userpg->index = perf_event_index(event);
5496 userpg->offset = perf_event_count(event);
5498 userpg->offset -= local64_read(&event->hw.prev_count);
5500 userpg->time_enabled = enabled +
5501 atomic64_read(&event->child_total_time_enabled);
5503 userpg->time_running = running +
5504 atomic64_read(&event->child_total_time_running);
5506 arch_perf_update_userpage(event, userpg, now);
5514 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5516 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5518 struct perf_event *event = vmf->vma->vm_file->private_data;
5519 struct perf_buffer *rb;
5520 vm_fault_t ret = VM_FAULT_SIGBUS;
5522 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5523 if (vmf->pgoff == 0)
5529 rb = rcu_dereference(event->rb);
5533 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5536 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5540 get_page(vmf->page);
5541 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5542 vmf->page->index = vmf->pgoff;
5551 static void ring_buffer_attach(struct perf_event *event,
5552 struct perf_buffer *rb)
5554 struct perf_buffer *old_rb = NULL;
5555 unsigned long flags;
5559 * Should be impossible, we set this when removing
5560 * event->rb_entry and wait/clear when adding event->rb_entry.
5562 WARN_ON_ONCE(event->rcu_pending);
5565 spin_lock_irqsave(&old_rb->event_lock, flags);
5566 list_del_rcu(&event->rb_entry);
5567 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5569 event->rcu_batches = get_state_synchronize_rcu();
5570 event->rcu_pending = 1;
5574 if (event->rcu_pending) {
5575 cond_synchronize_rcu(event->rcu_batches);
5576 event->rcu_pending = 0;
5579 spin_lock_irqsave(&rb->event_lock, flags);
5580 list_add_rcu(&event->rb_entry, &rb->event_list);
5581 spin_unlock_irqrestore(&rb->event_lock, flags);
5585 * Avoid racing with perf_mmap_close(AUX): stop the event
5586 * before swizzling the event::rb pointer; if it's getting
5587 * unmapped, its aux_mmap_count will be 0 and it won't
5588 * restart. See the comment in __perf_pmu_output_stop().
5590 * Data will inevitably be lost when set_output is done in
5591 * mid-air, but then again, whoever does it like this is
5592 * not in for the data anyway.
5595 perf_event_stop(event, 0);
5597 rcu_assign_pointer(event->rb, rb);
5600 ring_buffer_put(old_rb);
5602 * Since we detached before setting the new rb, so that we
5603 * could attach the new rb, we could have missed a wakeup.
5606 wake_up_all(&event->waitq);
5610 static void ring_buffer_wakeup(struct perf_event *event)
5612 struct perf_buffer *rb;
5615 rb = rcu_dereference(event->rb);
5617 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5618 wake_up_all(&event->waitq);
5623 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5625 struct perf_buffer *rb;
5628 rb = rcu_dereference(event->rb);
5630 if (!refcount_inc_not_zero(&rb->refcount))
5638 void ring_buffer_put(struct perf_buffer *rb)
5640 if (!refcount_dec_and_test(&rb->refcount))
5643 WARN_ON_ONCE(!list_empty(&rb->event_list));
5645 call_rcu(&rb->rcu_head, rb_free_rcu);
5648 static void perf_mmap_open(struct vm_area_struct *vma)
5650 struct perf_event *event = vma->vm_file->private_data;
5652 atomic_inc(&event->mmap_count);
5653 atomic_inc(&event->rb->mmap_count);
5656 atomic_inc(&event->rb->aux_mmap_count);
5658 if (event->pmu->event_mapped)
5659 event->pmu->event_mapped(event, vma->vm_mm);
5662 static void perf_pmu_output_stop(struct perf_event *event);
5665 * A buffer can be mmap()ed multiple times; either directly through the same
5666 * event, or through other events by use of perf_event_set_output().
5668 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5669 * the buffer here, where we still have a VM context. This means we need
5670 * to detach all events redirecting to us.
5672 static void perf_mmap_close(struct vm_area_struct *vma)
5674 struct perf_event *event = vma->vm_file->private_data;
5676 struct perf_buffer *rb = ring_buffer_get(event);
5677 struct user_struct *mmap_user = rb->mmap_user;
5678 int mmap_locked = rb->mmap_locked;
5679 unsigned long size = perf_data_size(rb);
5681 if (event->pmu->event_unmapped)
5682 event->pmu->event_unmapped(event, vma->vm_mm);
5685 * rb->aux_mmap_count will always drop before rb->mmap_count and
5686 * event->mmap_count, so it is ok to use event->mmap_mutex to
5687 * serialize with perf_mmap here.
5689 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5690 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5692 * Stop all AUX events that are writing to this buffer,
5693 * so that we can free its AUX pages and corresponding PMU
5694 * data. Note that after rb::aux_mmap_count dropped to zero,
5695 * they won't start any more (see perf_aux_output_begin()).
5697 perf_pmu_output_stop(event);
5699 /* now it's safe to free the pages */
5700 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
5701 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5703 /* this has to be the last one */
5705 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5707 mutex_unlock(&event->mmap_mutex);
5710 atomic_dec(&rb->mmap_count);
5712 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5715 ring_buffer_attach(event, NULL);
5716 mutex_unlock(&event->mmap_mutex);
5718 /* If there's still other mmap()s of this buffer, we're done. */
5719 if (atomic_read(&rb->mmap_count))
5723 * No other mmap()s, detach from all other events that might redirect
5724 * into the now unreachable buffer. Somewhat complicated by the
5725 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5729 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5730 if (!atomic_long_inc_not_zero(&event->refcount)) {
5732 * This event is en-route to free_event() which will
5733 * detach it and remove it from the list.
5739 mutex_lock(&event->mmap_mutex);
5741 * Check we didn't race with perf_event_set_output() which can
5742 * swizzle the rb from under us while we were waiting to
5743 * acquire mmap_mutex.
5745 * If we find a different rb; ignore this event, a next
5746 * iteration will no longer find it on the list. We have to
5747 * still restart the iteration to make sure we're not now
5748 * iterating the wrong list.
5750 if (event->rb == rb)
5751 ring_buffer_attach(event, NULL);
5753 mutex_unlock(&event->mmap_mutex);
5757 * Restart the iteration; either we're on the wrong list or
5758 * destroyed its integrity by doing a deletion.
5765 * It could be there's still a few 0-ref events on the list; they'll
5766 * get cleaned up by free_event() -- they'll also still have their
5767 * ref on the rb and will free it whenever they are done with it.
5769 * Aside from that, this buffer is 'fully' detached and unmapped,
5770 * undo the VM accounting.
5773 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5774 &mmap_user->locked_vm);
5775 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5776 free_uid(mmap_user);
5779 ring_buffer_put(rb); /* could be last */
5782 static const struct vm_operations_struct perf_mmap_vmops = {
5783 .open = perf_mmap_open,
5784 .close = perf_mmap_close, /* non mergeable */
5785 .fault = perf_mmap_fault,
5786 .page_mkwrite = perf_mmap_fault,
5789 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5791 struct perf_event *event = file->private_data;
5792 unsigned long user_locked, user_lock_limit;
5793 struct user_struct *user = current_user();
5794 struct perf_buffer *rb = NULL;
5795 unsigned long locked, lock_limit;
5796 unsigned long vma_size;
5797 unsigned long nr_pages;
5798 long user_extra = 0, extra = 0;
5799 int ret = 0, flags = 0;
5802 * Don't allow mmap() of inherited per-task counters. This would
5803 * create a performance issue due to all children writing to the
5806 if (event->cpu == -1 && event->attr.inherit)
5809 if (!(vma->vm_flags & VM_SHARED))
5812 ret = security_perf_event_read(event);
5816 vma_size = vma->vm_end - vma->vm_start;
5818 if (vma->vm_pgoff == 0) {
5819 nr_pages = (vma_size / PAGE_SIZE) - 1;
5822 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5823 * mapped, all subsequent mappings should have the same size
5824 * and offset. Must be above the normal perf buffer.
5826 u64 aux_offset, aux_size;
5831 nr_pages = vma_size / PAGE_SIZE;
5833 mutex_lock(&event->mmap_mutex);
5840 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5841 aux_size = READ_ONCE(rb->user_page->aux_size);
5843 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5846 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5849 /* already mapped with a different offset */
5850 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5853 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5856 /* already mapped with a different size */
5857 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5860 if (!is_power_of_2(nr_pages))
5863 if (!atomic_inc_not_zero(&rb->mmap_count))
5866 if (rb_has_aux(rb)) {
5867 atomic_inc(&rb->aux_mmap_count);
5872 atomic_set(&rb->aux_mmap_count, 1);
5873 user_extra = nr_pages;
5879 * If we have rb pages ensure they're a power-of-two number, so we
5880 * can do bitmasks instead of modulo.
5882 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5885 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5888 WARN_ON_ONCE(event->ctx->parent_ctx);
5890 mutex_lock(&event->mmap_mutex);
5892 if (event->rb->nr_pages != nr_pages) {
5897 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5899 * Raced against perf_mmap_close() through
5900 * perf_event_set_output(). Try again, hope for better
5903 mutex_unlock(&event->mmap_mutex);
5910 user_extra = nr_pages + 1;
5913 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5916 * Increase the limit linearly with more CPUs:
5918 user_lock_limit *= num_online_cpus();
5920 user_locked = atomic_long_read(&user->locked_vm);
5923 * sysctl_perf_event_mlock may have changed, so that
5924 * user->locked_vm > user_lock_limit
5926 if (user_locked > user_lock_limit)
5927 user_locked = user_lock_limit;
5928 user_locked += user_extra;
5930 if (user_locked > user_lock_limit) {
5932 * charge locked_vm until it hits user_lock_limit;
5933 * charge the rest from pinned_vm
5935 extra = user_locked - user_lock_limit;
5936 user_extra -= extra;
5939 lock_limit = rlimit(RLIMIT_MEMLOCK);
5940 lock_limit >>= PAGE_SHIFT;
5941 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5943 if ((locked > lock_limit) && perf_is_paranoid() &&
5944 !capable(CAP_IPC_LOCK)) {
5949 WARN_ON(!rb && event->rb);
5951 if (vma->vm_flags & VM_WRITE)
5952 flags |= RING_BUFFER_WRITABLE;
5955 rb = rb_alloc(nr_pages,
5956 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5964 atomic_set(&rb->mmap_count, 1);
5965 rb->mmap_user = get_current_user();
5966 rb->mmap_locked = extra;
5968 ring_buffer_attach(event, rb);
5970 perf_event_init_userpage(event);
5971 perf_event_update_userpage(event);
5973 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5974 event->attr.aux_watermark, flags);
5976 rb->aux_mmap_locked = extra;
5981 atomic_long_add(user_extra, &user->locked_vm);
5982 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5984 atomic_inc(&event->mmap_count);
5986 atomic_dec(&rb->mmap_count);
5989 mutex_unlock(&event->mmap_mutex);
5992 * Since pinned accounting is per vm we cannot allow fork() to copy our
5995 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5996 vma->vm_ops = &perf_mmap_vmops;
5998 if (event->pmu->event_mapped)
5999 event->pmu->event_mapped(event, vma->vm_mm);
6004 static int perf_fasync(int fd, struct file *filp, int on)
6006 struct inode *inode = file_inode(filp);
6007 struct perf_event *event = filp->private_data;
6011 retval = fasync_helper(fd, filp, on, &event->fasync);
6012 inode_unlock(inode);
6020 static const struct file_operations perf_fops = {
6021 .llseek = no_llseek,
6022 .release = perf_release,
6025 .unlocked_ioctl = perf_ioctl,
6026 .compat_ioctl = perf_compat_ioctl,
6028 .fasync = perf_fasync,
6034 * If there's data, ensure we set the poll() state and publish everything
6035 * to user-space before waking everybody up.
6038 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6040 /* only the parent has fasync state */
6042 event = event->parent;
6043 return &event->fasync;
6046 void perf_event_wakeup(struct perf_event *event)
6048 ring_buffer_wakeup(event);
6050 if (event->pending_kill) {
6051 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6052 event->pending_kill = 0;
6056 static void perf_pending_event_disable(struct perf_event *event)
6058 int cpu = READ_ONCE(event->pending_disable);
6063 if (cpu == smp_processor_id()) {
6064 WRITE_ONCE(event->pending_disable, -1);
6065 perf_event_disable_local(event);
6072 * perf_event_disable_inatomic()
6073 * @pending_disable = CPU-A;
6077 * @pending_disable = -1;
6080 * perf_event_disable_inatomic()
6081 * @pending_disable = CPU-B;
6082 * irq_work_queue(); // FAILS
6085 * perf_pending_event()
6087 * But the event runs on CPU-B and wants disabling there.
6089 irq_work_queue_on(&event->pending, cpu);
6092 static void perf_pending_event(struct irq_work *entry)
6094 struct perf_event *event = container_of(entry, struct perf_event, pending);
6097 rctx = perf_swevent_get_recursion_context();
6099 * If we 'fail' here, that's OK, it means recursion is already disabled
6100 * and we won't recurse 'further'.
6103 perf_pending_event_disable(event);
6105 if (event->pending_wakeup) {
6106 event->pending_wakeup = 0;
6107 perf_event_wakeup(event);
6111 perf_swevent_put_recursion_context(rctx);
6115 * We assume there is only KVM supporting the callbacks.
6116 * Later on, we might change it to a list if there is
6117 * another virtualization implementation supporting the callbacks.
6119 struct perf_guest_info_callbacks *perf_guest_cbs;
6121 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6123 perf_guest_cbs = cbs;
6126 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6128 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6130 perf_guest_cbs = NULL;
6133 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6136 perf_output_sample_regs(struct perf_output_handle *handle,
6137 struct pt_regs *regs, u64 mask)
6140 DECLARE_BITMAP(_mask, 64);
6142 bitmap_from_u64(_mask, mask);
6143 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6146 val = perf_reg_value(regs, bit);
6147 perf_output_put(handle, val);
6151 static void perf_sample_regs_user(struct perf_regs *regs_user,
6152 struct pt_regs *regs,
6153 struct pt_regs *regs_user_copy)
6155 if (user_mode(regs)) {
6156 regs_user->abi = perf_reg_abi(current);
6157 regs_user->regs = regs;
6158 } else if (!(current->flags & PF_KTHREAD)) {
6159 perf_get_regs_user(regs_user, regs, regs_user_copy);
6161 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6162 regs_user->regs = NULL;
6166 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6167 struct pt_regs *regs)
6169 regs_intr->regs = regs;
6170 regs_intr->abi = perf_reg_abi(current);
6175 * Get remaining task size from user stack pointer.
6177 * It'd be better to take stack vma map and limit this more
6178 * precisely, but there's no way to get it safely under interrupt,
6179 * so using TASK_SIZE as limit.
6181 static u64 perf_ustack_task_size(struct pt_regs *regs)
6183 unsigned long addr = perf_user_stack_pointer(regs);
6185 if (!addr || addr >= TASK_SIZE)
6188 return TASK_SIZE - addr;
6192 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6193 struct pt_regs *regs)
6197 /* No regs, no stack pointer, no dump. */
6202 * Check if we fit in with the requested stack size into the:
6204 * If we don't, we limit the size to the TASK_SIZE.
6206 * - remaining sample size
6207 * If we don't, we customize the stack size to
6208 * fit in to the remaining sample size.
6211 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6212 stack_size = min(stack_size, (u16) task_size);
6214 /* Current header size plus static size and dynamic size. */
6215 header_size += 2 * sizeof(u64);
6217 /* Do we fit in with the current stack dump size? */
6218 if ((u16) (header_size + stack_size) < header_size) {
6220 * If we overflow the maximum size for the sample,
6221 * we customize the stack dump size to fit in.
6223 stack_size = USHRT_MAX - header_size - sizeof(u64);
6224 stack_size = round_up(stack_size, sizeof(u64));
6231 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6232 struct pt_regs *regs)
6234 /* Case of a kernel thread, nothing to dump */
6237 perf_output_put(handle, size);
6247 * - the size requested by user or the best one we can fit
6248 * in to the sample max size
6250 * - user stack dump data
6252 * - the actual dumped size
6256 perf_output_put(handle, dump_size);
6259 sp = perf_user_stack_pointer(regs);
6262 rem = __output_copy_user(handle, (void *) sp, dump_size);
6264 dyn_size = dump_size - rem;
6266 perf_output_skip(handle, rem);
6269 perf_output_put(handle, dyn_size);
6273 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6274 struct perf_sample_data *data,
6277 struct perf_event *sampler = event->aux_event;
6278 struct perf_buffer *rb;
6285 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6288 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6291 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6296 * If this is an NMI hit inside sampling code, don't take
6297 * the sample. See also perf_aux_sample_output().
6299 if (READ_ONCE(rb->aux_in_sampling)) {
6302 size = min_t(size_t, size, perf_aux_size(rb));
6303 data->aux_size = ALIGN(size, sizeof(u64));
6305 ring_buffer_put(rb);
6308 return data->aux_size;
6311 long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6312 struct perf_event *event,
6313 struct perf_output_handle *handle,
6316 unsigned long flags;
6320 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6321 * paths. If we start calling them in NMI context, they may race with
6322 * the IRQ ones, that is, for example, re-starting an event that's just
6323 * been stopped, which is why we're using a separate callback that
6324 * doesn't change the event state.
6326 * IRQs need to be disabled to prevent IPIs from racing with us.
6328 local_irq_save(flags);
6330 * Guard against NMI hits inside the critical section;
6331 * see also perf_prepare_sample_aux().
6333 WRITE_ONCE(rb->aux_in_sampling, 1);
6336 ret = event->pmu->snapshot_aux(event, handle, size);
6339 WRITE_ONCE(rb->aux_in_sampling, 0);
6340 local_irq_restore(flags);
6345 static void perf_aux_sample_output(struct perf_event *event,
6346 struct perf_output_handle *handle,
6347 struct perf_sample_data *data)
6349 struct perf_event *sampler = event->aux_event;
6350 struct perf_buffer *rb;
6354 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6357 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6361 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6364 * An error here means that perf_output_copy() failed (returned a
6365 * non-zero surplus that it didn't copy), which in its current
6366 * enlightened implementation is not possible. If that changes, we'd
6369 if (WARN_ON_ONCE(size < 0))
6373 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6374 * perf_prepare_sample_aux(), so should not be more than that.
6376 pad = data->aux_size - size;
6377 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6382 perf_output_copy(handle, &zero, pad);
6386 ring_buffer_put(rb);
6389 static void __perf_event_header__init_id(struct perf_event_header *header,
6390 struct perf_sample_data *data,
6391 struct perf_event *event)
6393 u64 sample_type = event->attr.sample_type;
6395 data->type = sample_type;
6396 header->size += event->id_header_size;
6398 if (sample_type & PERF_SAMPLE_TID) {
6399 /* namespace issues */
6400 data->tid_entry.pid = perf_event_pid(event, current);
6401 data->tid_entry.tid = perf_event_tid(event, current);
6404 if (sample_type & PERF_SAMPLE_TIME)
6405 data->time = perf_event_clock(event);
6407 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6408 data->id = primary_event_id(event);
6410 if (sample_type & PERF_SAMPLE_STREAM_ID)
6411 data->stream_id = event->id;
6413 if (sample_type & PERF_SAMPLE_CPU) {
6414 data->cpu_entry.cpu = raw_smp_processor_id();
6415 data->cpu_entry.reserved = 0;
6419 void perf_event_header__init_id(struct perf_event_header *header,
6420 struct perf_sample_data *data,
6421 struct perf_event *event)
6423 if (event->attr.sample_id_all)
6424 __perf_event_header__init_id(header, data, event);
6427 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6428 struct perf_sample_data *data)
6430 u64 sample_type = data->type;
6432 if (sample_type & PERF_SAMPLE_TID)
6433 perf_output_put(handle, data->tid_entry);
6435 if (sample_type & PERF_SAMPLE_TIME)
6436 perf_output_put(handle, data->time);
6438 if (sample_type & PERF_SAMPLE_ID)
6439 perf_output_put(handle, data->id);
6441 if (sample_type & PERF_SAMPLE_STREAM_ID)
6442 perf_output_put(handle, data->stream_id);
6444 if (sample_type & PERF_SAMPLE_CPU)
6445 perf_output_put(handle, data->cpu_entry);
6447 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6448 perf_output_put(handle, data->id);
6451 void perf_event__output_id_sample(struct perf_event *event,
6452 struct perf_output_handle *handle,
6453 struct perf_sample_data *sample)
6455 if (event->attr.sample_id_all)
6456 __perf_event__output_id_sample(handle, sample);
6459 static void perf_output_read_one(struct perf_output_handle *handle,
6460 struct perf_event *event,
6461 u64 enabled, u64 running)
6463 u64 read_format = event->attr.read_format;
6467 values[n++] = perf_event_count(event);
6468 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6469 values[n++] = enabled +
6470 atomic64_read(&event->child_total_time_enabled);
6472 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6473 values[n++] = running +
6474 atomic64_read(&event->child_total_time_running);
6476 if (read_format & PERF_FORMAT_ID)
6477 values[n++] = primary_event_id(event);
6479 __output_copy(handle, values, n * sizeof(u64));
6482 static void perf_output_read_group(struct perf_output_handle *handle,
6483 struct perf_event *event,
6484 u64 enabled, u64 running)
6486 struct perf_event *leader = event->group_leader, *sub;
6487 u64 read_format = event->attr.read_format;
6491 values[n++] = 1 + leader->nr_siblings;
6493 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6494 values[n++] = enabled;
6496 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6497 values[n++] = running;
6499 if ((leader != event) &&
6500 (leader->state == PERF_EVENT_STATE_ACTIVE))
6501 leader->pmu->read(leader);
6503 values[n++] = perf_event_count(leader);
6504 if (read_format & PERF_FORMAT_ID)
6505 values[n++] = primary_event_id(leader);
6507 __output_copy(handle, values, n * sizeof(u64));
6509 for_each_sibling_event(sub, leader) {
6512 if ((sub != event) &&
6513 (sub->state == PERF_EVENT_STATE_ACTIVE))
6514 sub->pmu->read(sub);
6516 values[n++] = perf_event_count(sub);
6517 if (read_format & PERF_FORMAT_ID)
6518 values[n++] = primary_event_id(sub);
6520 __output_copy(handle, values, n * sizeof(u64));
6524 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6525 PERF_FORMAT_TOTAL_TIME_RUNNING)
6528 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6530 * The problem is that its both hard and excessively expensive to iterate the
6531 * child list, not to mention that its impossible to IPI the children running
6532 * on another CPU, from interrupt/NMI context.
6534 static void perf_output_read(struct perf_output_handle *handle,
6535 struct perf_event *event)
6537 u64 enabled = 0, running = 0, now;
6538 u64 read_format = event->attr.read_format;
6541 * compute total_time_enabled, total_time_running
6542 * based on snapshot values taken when the event
6543 * was last scheduled in.
6545 * we cannot simply called update_context_time()
6546 * because of locking issue as we are called in
6549 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6550 calc_timer_values(event, &now, &enabled, &running);
6552 if (event->attr.read_format & PERF_FORMAT_GROUP)
6553 perf_output_read_group(handle, event, enabled, running);
6555 perf_output_read_one(handle, event, enabled, running);
6558 void perf_output_sample(struct perf_output_handle *handle,
6559 struct perf_event_header *header,
6560 struct perf_sample_data *data,
6561 struct perf_event *event)
6563 u64 sample_type = data->type;
6565 perf_output_put(handle, *header);
6567 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6568 perf_output_put(handle, data->id);
6570 if (sample_type & PERF_SAMPLE_IP)
6571 perf_output_put(handle, data->ip);
6573 if (sample_type & PERF_SAMPLE_TID)
6574 perf_output_put(handle, data->tid_entry);
6576 if (sample_type & PERF_SAMPLE_TIME)
6577 perf_output_put(handle, data->time);
6579 if (sample_type & PERF_SAMPLE_ADDR)
6580 perf_output_put(handle, data->addr);
6582 if (sample_type & PERF_SAMPLE_ID)
6583 perf_output_put(handle, data->id);
6585 if (sample_type & PERF_SAMPLE_STREAM_ID)
6586 perf_output_put(handle, data->stream_id);
6588 if (sample_type & PERF_SAMPLE_CPU)
6589 perf_output_put(handle, data->cpu_entry);
6591 if (sample_type & PERF_SAMPLE_PERIOD)
6592 perf_output_put(handle, data->period);
6594 if (sample_type & PERF_SAMPLE_READ)
6595 perf_output_read(handle, event);
6597 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6600 size += data->callchain->nr;
6601 size *= sizeof(u64);
6602 __output_copy(handle, data->callchain, size);
6605 if (sample_type & PERF_SAMPLE_RAW) {
6606 struct perf_raw_record *raw = data->raw;
6609 struct perf_raw_frag *frag = &raw->frag;
6611 perf_output_put(handle, raw->size);
6614 __output_custom(handle, frag->copy,
6615 frag->data, frag->size);
6617 __output_copy(handle, frag->data,
6620 if (perf_raw_frag_last(frag))
6625 __output_skip(handle, NULL, frag->pad);
6631 .size = sizeof(u32),
6634 perf_output_put(handle, raw);
6638 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6639 if (data->br_stack) {
6642 size = data->br_stack->nr
6643 * sizeof(struct perf_branch_entry);
6645 perf_output_put(handle, data->br_stack->nr);
6646 perf_output_copy(handle, data->br_stack->entries, size);
6649 * we always store at least the value of nr
6652 perf_output_put(handle, nr);
6656 if (sample_type & PERF_SAMPLE_REGS_USER) {
6657 u64 abi = data->regs_user.abi;
6660 * If there are no regs to dump, notice it through
6661 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6663 perf_output_put(handle, abi);
6666 u64 mask = event->attr.sample_regs_user;
6667 perf_output_sample_regs(handle,
6668 data->regs_user.regs,
6673 if (sample_type & PERF_SAMPLE_STACK_USER) {
6674 perf_output_sample_ustack(handle,
6675 data->stack_user_size,
6676 data->regs_user.regs);
6679 if (sample_type & PERF_SAMPLE_WEIGHT)
6680 perf_output_put(handle, data->weight);
6682 if (sample_type & PERF_SAMPLE_DATA_SRC)
6683 perf_output_put(handle, data->data_src.val);
6685 if (sample_type & PERF_SAMPLE_TRANSACTION)
6686 perf_output_put(handle, data->txn);
6688 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6689 u64 abi = data->regs_intr.abi;
6691 * If there are no regs to dump, notice it through
6692 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6694 perf_output_put(handle, abi);
6697 u64 mask = event->attr.sample_regs_intr;
6699 perf_output_sample_regs(handle,
6700 data->regs_intr.regs,
6705 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6706 perf_output_put(handle, data->phys_addr);
6708 if (sample_type & PERF_SAMPLE_AUX) {
6709 perf_output_put(handle, data->aux_size);
6712 perf_aux_sample_output(event, handle, data);
6715 if (!event->attr.watermark) {
6716 int wakeup_events = event->attr.wakeup_events;
6718 if (wakeup_events) {
6719 struct perf_buffer *rb = handle->rb;
6720 int events = local_inc_return(&rb->events);
6722 if (events >= wakeup_events) {
6723 local_sub(wakeup_events, &rb->events);
6724 local_inc(&rb->wakeup);
6730 static u64 perf_virt_to_phys(u64 virt)
6733 struct page *p = NULL;
6738 if (virt >= TASK_SIZE) {
6739 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6740 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6741 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6742 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6745 * Walking the pages tables for user address.
6746 * Interrupts are disabled, so it prevents any tear down
6747 * of the page tables.
6748 * Try IRQ-safe __get_user_pages_fast first.
6749 * If failed, leave phys_addr as 0.
6751 if ((current->mm != NULL) &&
6752 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6753 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6762 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6764 struct perf_callchain_entry *
6765 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6767 bool kernel = !event->attr.exclude_callchain_kernel;
6768 bool user = !event->attr.exclude_callchain_user;
6769 /* Disallow cross-task user callchains. */
6770 bool crosstask = event->ctx->task && event->ctx->task != current;
6771 const u32 max_stack = event->attr.sample_max_stack;
6772 struct perf_callchain_entry *callchain;
6774 if (!kernel && !user)
6775 return &__empty_callchain;
6777 callchain = get_perf_callchain(regs, 0, kernel, user,
6778 max_stack, crosstask, true);
6779 return callchain ?: &__empty_callchain;
6782 void perf_prepare_sample(struct perf_event_header *header,
6783 struct perf_sample_data *data,
6784 struct perf_event *event,
6785 struct pt_regs *regs)
6787 u64 sample_type = event->attr.sample_type;
6789 header->type = PERF_RECORD_SAMPLE;
6790 header->size = sizeof(*header) + event->header_size;
6793 header->misc |= perf_misc_flags(regs);
6795 __perf_event_header__init_id(header, data, event);
6797 if (sample_type & PERF_SAMPLE_IP)
6798 data->ip = perf_instruction_pointer(regs);
6800 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6803 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6804 data->callchain = perf_callchain(event, regs);
6806 size += data->callchain->nr;
6808 header->size += size * sizeof(u64);
6811 if (sample_type & PERF_SAMPLE_RAW) {
6812 struct perf_raw_record *raw = data->raw;
6816 struct perf_raw_frag *frag = &raw->frag;
6821 if (perf_raw_frag_last(frag))
6826 size = round_up(sum + sizeof(u32), sizeof(u64));
6827 raw->size = size - sizeof(u32);
6828 frag->pad = raw->size - sum;
6833 header->size += size;
6836 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6837 int size = sizeof(u64); /* nr */
6838 if (data->br_stack) {
6839 size += data->br_stack->nr
6840 * sizeof(struct perf_branch_entry);
6842 header->size += size;
6845 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6846 perf_sample_regs_user(&data->regs_user, regs,
6847 &data->regs_user_copy);
6849 if (sample_type & PERF_SAMPLE_REGS_USER) {
6850 /* regs dump ABI info */
6851 int size = sizeof(u64);
6853 if (data->regs_user.regs) {
6854 u64 mask = event->attr.sample_regs_user;
6855 size += hweight64(mask) * sizeof(u64);
6858 header->size += size;
6861 if (sample_type & PERF_SAMPLE_STACK_USER) {
6863 * Either we need PERF_SAMPLE_STACK_USER bit to be always
6864 * processed as the last one or have additional check added
6865 * in case new sample type is added, because we could eat
6866 * up the rest of the sample size.
6868 u16 stack_size = event->attr.sample_stack_user;
6869 u16 size = sizeof(u64);
6871 stack_size = perf_sample_ustack_size(stack_size, header->size,
6872 data->regs_user.regs);
6875 * If there is something to dump, add space for the dump
6876 * itself and for the field that tells the dynamic size,
6877 * which is how many have been actually dumped.
6880 size += sizeof(u64) + stack_size;
6882 data->stack_user_size = stack_size;
6883 header->size += size;
6886 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6887 /* regs dump ABI info */
6888 int size = sizeof(u64);
6890 perf_sample_regs_intr(&data->regs_intr, regs);
6892 if (data->regs_intr.regs) {
6893 u64 mask = event->attr.sample_regs_intr;
6895 size += hweight64(mask) * sizeof(u64);
6898 header->size += size;
6901 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6902 data->phys_addr = perf_virt_to_phys(data->addr);
6904 if (sample_type & PERF_SAMPLE_AUX) {
6907 header->size += sizeof(u64); /* size */
6910 * Given the 16bit nature of header::size, an AUX sample can
6911 * easily overflow it, what with all the preceding sample bits.
6912 * Make sure this doesn't happen by using up to U16_MAX bytes
6913 * per sample in total (rounded down to 8 byte boundary).
6915 size = min_t(size_t, U16_MAX - header->size,
6916 event->attr.aux_sample_size);
6917 size = rounddown(size, 8);
6918 size = perf_prepare_sample_aux(event, data, size);
6920 WARN_ON_ONCE(size + header->size > U16_MAX);
6921 header->size += size;
6924 * If you're adding more sample types here, you likely need to do
6925 * something about the overflowing header::size, like repurpose the
6926 * lowest 3 bits of size, which should be always zero at the moment.
6927 * This raises a more important question, do we really need 512k sized
6928 * samples and why, so good argumentation is in order for whatever you
6931 WARN_ON_ONCE(header->size & 7);
6934 static __always_inline int
6935 __perf_event_output(struct perf_event *event,
6936 struct perf_sample_data *data,
6937 struct pt_regs *regs,
6938 int (*output_begin)(struct perf_output_handle *,
6939 struct perf_event *,
6942 struct perf_output_handle handle;
6943 struct perf_event_header header;
6946 /* protect the callchain buffers */
6949 perf_prepare_sample(&header, data, event, regs);
6951 err = output_begin(&handle, event, header.size);
6955 perf_output_sample(&handle, &header, data, event);
6957 perf_output_end(&handle);
6965 perf_event_output_forward(struct perf_event *event,
6966 struct perf_sample_data *data,
6967 struct pt_regs *regs)
6969 __perf_event_output(event, data, regs, perf_output_begin_forward);
6973 perf_event_output_backward(struct perf_event *event,
6974 struct perf_sample_data *data,
6975 struct pt_regs *regs)
6977 __perf_event_output(event, data, regs, perf_output_begin_backward);
6981 perf_event_output(struct perf_event *event,
6982 struct perf_sample_data *data,
6983 struct pt_regs *regs)
6985 return __perf_event_output(event, data, regs, perf_output_begin);
6992 struct perf_read_event {
6993 struct perf_event_header header;
7000 perf_event_read_event(struct perf_event *event,
7001 struct task_struct *task)
7003 struct perf_output_handle handle;
7004 struct perf_sample_data sample;
7005 struct perf_read_event read_event = {
7007 .type = PERF_RECORD_READ,
7009 .size = sizeof(read_event) + event->read_size,
7011 .pid = perf_event_pid(event, task),
7012 .tid = perf_event_tid(event, task),
7016 perf_event_header__init_id(&read_event.header, &sample, event);
7017 ret = perf_output_begin(&handle, event, read_event.header.size);
7021 perf_output_put(&handle, read_event);
7022 perf_output_read(&handle, event);
7023 perf_event__output_id_sample(event, &handle, &sample);
7025 perf_output_end(&handle);
7028 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7031 perf_iterate_ctx(struct perf_event_context *ctx,
7032 perf_iterate_f output,
7033 void *data, bool all)
7035 struct perf_event *event;
7037 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7039 if (event->state < PERF_EVENT_STATE_INACTIVE)
7041 if (!event_filter_match(event))
7045 output(event, data);
7049 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7051 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7052 struct perf_event *event;
7054 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7056 * Skip events that are not fully formed yet; ensure that
7057 * if we observe event->ctx, both event and ctx will be
7058 * complete enough. See perf_install_in_context().
7060 if (!smp_load_acquire(&event->ctx))
7063 if (event->state < PERF_EVENT_STATE_INACTIVE)
7065 if (!event_filter_match(event))
7067 output(event, data);
7072 * Iterate all events that need to receive side-band events.
7074 * For new callers; ensure that account_pmu_sb_event() includes
7075 * your event, otherwise it might not get delivered.
7078 perf_iterate_sb(perf_iterate_f output, void *data,
7079 struct perf_event_context *task_ctx)
7081 struct perf_event_context *ctx;
7088 * If we have task_ctx != NULL we only notify the task context itself.
7089 * The task_ctx is set only for EXIT events before releasing task
7093 perf_iterate_ctx(task_ctx, output, data, false);
7097 perf_iterate_sb_cpu(output, data);
7099 for_each_task_context_nr(ctxn) {
7100 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7102 perf_iterate_ctx(ctx, output, data, false);
7110 * Clear all file-based filters at exec, they'll have to be
7111 * re-instated when/if these objects are mmapped again.
7113 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7115 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7116 struct perf_addr_filter *filter;
7117 unsigned int restart = 0, count = 0;
7118 unsigned long flags;
7120 if (!has_addr_filter(event))
7123 raw_spin_lock_irqsave(&ifh->lock, flags);
7124 list_for_each_entry(filter, &ifh->list, entry) {
7125 if (filter->path.dentry) {
7126 event->addr_filter_ranges[count].start = 0;
7127 event->addr_filter_ranges[count].size = 0;
7135 event->addr_filters_gen++;
7136 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7139 perf_event_stop(event, 1);
7142 void perf_event_exec(void)
7144 struct perf_event_context *ctx;
7148 for_each_task_context_nr(ctxn) {
7149 ctx = current->perf_event_ctxp[ctxn];
7153 perf_event_enable_on_exec(ctxn);
7155 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
7161 struct remote_output {
7162 struct perf_buffer *rb;
7166 static void __perf_event_output_stop(struct perf_event *event, void *data)
7168 struct perf_event *parent = event->parent;
7169 struct remote_output *ro = data;
7170 struct perf_buffer *rb = ro->rb;
7171 struct stop_event_data sd = {
7175 if (!has_aux(event))
7182 * In case of inheritance, it will be the parent that links to the
7183 * ring-buffer, but it will be the child that's actually using it.
7185 * We are using event::rb to determine if the event should be stopped,
7186 * however this may race with ring_buffer_attach() (through set_output),
7187 * which will make us skip the event that actually needs to be stopped.
7188 * So ring_buffer_attach() has to stop an aux event before re-assigning
7191 if (rcu_dereference(parent->rb) == rb)
7192 ro->err = __perf_event_stop(&sd);
7195 static int __perf_pmu_output_stop(void *info)
7197 struct perf_event *event = info;
7198 struct pmu *pmu = event->ctx->pmu;
7199 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7200 struct remote_output ro = {
7205 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7206 if (cpuctx->task_ctx)
7207 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7214 static void perf_pmu_output_stop(struct perf_event *event)
7216 struct perf_event *iter;
7221 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7223 * For per-CPU events, we need to make sure that neither they
7224 * nor their children are running; for cpu==-1 events it's
7225 * sufficient to stop the event itself if it's active, since
7226 * it can't have children.
7230 cpu = READ_ONCE(iter->oncpu);
7235 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7236 if (err == -EAGAIN) {
7245 * task tracking -- fork/exit
7247 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7250 struct perf_task_event {
7251 struct task_struct *task;
7252 struct perf_event_context *task_ctx;
7255 struct perf_event_header header;
7265 static int perf_event_task_match(struct perf_event *event)
7267 return event->attr.comm || event->attr.mmap ||
7268 event->attr.mmap2 || event->attr.mmap_data ||
7272 static void perf_event_task_output(struct perf_event *event,
7275 struct perf_task_event *task_event = data;
7276 struct perf_output_handle handle;
7277 struct perf_sample_data sample;
7278 struct task_struct *task = task_event->task;
7279 int ret, size = task_event->event_id.header.size;
7281 if (!perf_event_task_match(event))
7284 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7286 ret = perf_output_begin(&handle, event,
7287 task_event->event_id.header.size);
7291 task_event->event_id.pid = perf_event_pid(event, task);
7292 task_event->event_id.ppid = perf_event_pid(event, current);
7294 task_event->event_id.tid = perf_event_tid(event, task);
7295 task_event->event_id.ptid = perf_event_tid(event, current);
7297 task_event->event_id.time = perf_event_clock(event);
7299 perf_output_put(&handle, task_event->event_id);
7301 perf_event__output_id_sample(event, &handle, &sample);
7303 perf_output_end(&handle);
7305 task_event->event_id.header.size = size;
7308 static void perf_event_task(struct task_struct *task,
7309 struct perf_event_context *task_ctx,
7312 struct perf_task_event task_event;
7314 if (!atomic_read(&nr_comm_events) &&
7315 !atomic_read(&nr_mmap_events) &&
7316 !atomic_read(&nr_task_events))
7319 task_event = (struct perf_task_event){
7321 .task_ctx = task_ctx,
7324 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7326 .size = sizeof(task_event.event_id),
7336 perf_iterate_sb(perf_event_task_output,
7341 void perf_event_fork(struct task_struct *task)
7343 perf_event_task(task, NULL, 1);
7344 perf_event_namespaces(task);
7351 struct perf_comm_event {
7352 struct task_struct *task;
7357 struct perf_event_header header;
7364 static int perf_event_comm_match(struct perf_event *event)
7366 return event->attr.comm;
7369 static void perf_event_comm_output(struct perf_event *event,
7372 struct perf_comm_event *comm_event = data;
7373 struct perf_output_handle handle;
7374 struct perf_sample_data sample;
7375 int size = comm_event->event_id.header.size;
7378 if (!perf_event_comm_match(event))
7381 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7382 ret = perf_output_begin(&handle, event,
7383 comm_event->event_id.header.size);
7388 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7389 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7391 perf_output_put(&handle, comm_event->event_id);
7392 __output_copy(&handle, comm_event->comm,
7393 comm_event->comm_size);
7395 perf_event__output_id_sample(event, &handle, &sample);
7397 perf_output_end(&handle);
7399 comm_event->event_id.header.size = size;
7402 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7404 char comm[TASK_COMM_LEN];
7407 memset(comm, 0, sizeof(comm));
7408 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7409 size = ALIGN(strlen(comm)+1, sizeof(u64));
7411 comm_event->comm = comm;
7412 comm_event->comm_size = size;
7414 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7416 perf_iterate_sb(perf_event_comm_output,
7421 void perf_event_comm(struct task_struct *task, bool exec)
7423 struct perf_comm_event comm_event;
7425 if (!atomic_read(&nr_comm_events))
7428 comm_event = (struct perf_comm_event){
7434 .type = PERF_RECORD_COMM,
7435 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7443 perf_event_comm_event(&comm_event);
7447 * namespaces tracking
7450 struct perf_namespaces_event {
7451 struct task_struct *task;
7454 struct perf_event_header header;
7459 struct perf_ns_link_info link_info[NR_NAMESPACES];
7463 static int perf_event_namespaces_match(struct perf_event *event)
7465 return event->attr.namespaces;
7468 static void perf_event_namespaces_output(struct perf_event *event,
7471 struct perf_namespaces_event *namespaces_event = data;
7472 struct perf_output_handle handle;
7473 struct perf_sample_data sample;
7474 u16 header_size = namespaces_event->event_id.header.size;
7477 if (!perf_event_namespaces_match(event))
7480 perf_event_header__init_id(&namespaces_event->event_id.header,
7482 ret = perf_output_begin(&handle, event,
7483 namespaces_event->event_id.header.size);
7487 namespaces_event->event_id.pid = perf_event_pid(event,
7488 namespaces_event->task);
7489 namespaces_event->event_id.tid = perf_event_tid(event,
7490 namespaces_event->task);
7492 perf_output_put(&handle, namespaces_event->event_id);
7494 perf_event__output_id_sample(event, &handle, &sample);
7496 perf_output_end(&handle);
7498 namespaces_event->event_id.header.size = header_size;
7501 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7502 struct task_struct *task,
7503 const struct proc_ns_operations *ns_ops)
7505 struct path ns_path;
7506 struct inode *ns_inode;
7509 error = ns_get_path(&ns_path, task, ns_ops);
7511 ns_inode = ns_path.dentry->d_inode;
7512 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7513 ns_link_info->ino = ns_inode->i_ino;
7518 void perf_event_namespaces(struct task_struct *task)
7520 struct perf_namespaces_event namespaces_event;
7521 struct perf_ns_link_info *ns_link_info;
7523 if (!atomic_read(&nr_namespaces_events))
7526 namespaces_event = (struct perf_namespaces_event){
7530 .type = PERF_RECORD_NAMESPACES,
7532 .size = sizeof(namespaces_event.event_id),
7536 .nr_namespaces = NR_NAMESPACES,
7537 /* .link_info[NR_NAMESPACES] */
7541 ns_link_info = namespaces_event.event_id.link_info;
7543 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7544 task, &mntns_operations);
7546 #ifdef CONFIG_USER_NS
7547 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7548 task, &userns_operations);
7550 #ifdef CONFIG_NET_NS
7551 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7552 task, &netns_operations);
7554 #ifdef CONFIG_UTS_NS
7555 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7556 task, &utsns_operations);
7558 #ifdef CONFIG_IPC_NS
7559 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7560 task, &ipcns_operations);
7562 #ifdef CONFIG_PID_NS
7563 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7564 task, &pidns_operations);
7566 #ifdef CONFIG_CGROUPS
7567 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7568 task, &cgroupns_operations);
7571 perf_iterate_sb(perf_event_namespaces_output,
7580 struct perf_mmap_event {
7581 struct vm_area_struct *vma;
7583 const char *file_name;
7591 struct perf_event_header header;
7601 static int perf_event_mmap_match(struct perf_event *event,
7604 struct perf_mmap_event *mmap_event = data;
7605 struct vm_area_struct *vma = mmap_event->vma;
7606 int executable = vma->vm_flags & VM_EXEC;
7608 return (!executable && event->attr.mmap_data) ||
7609 (executable && (event->attr.mmap || event->attr.mmap2));
7612 static void perf_event_mmap_output(struct perf_event *event,
7615 struct perf_mmap_event *mmap_event = data;
7616 struct perf_output_handle handle;
7617 struct perf_sample_data sample;
7618 int size = mmap_event->event_id.header.size;
7619 u32 type = mmap_event->event_id.header.type;
7622 if (!perf_event_mmap_match(event, data))
7625 if (event->attr.mmap2) {
7626 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7627 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7628 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7629 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7630 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7631 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7632 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7635 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7636 ret = perf_output_begin(&handle, event,
7637 mmap_event->event_id.header.size);
7641 mmap_event->event_id.pid = perf_event_pid(event, current);
7642 mmap_event->event_id.tid = perf_event_tid(event, current);
7644 perf_output_put(&handle, mmap_event->event_id);
7646 if (event->attr.mmap2) {
7647 perf_output_put(&handle, mmap_event->maj);
7648 perf_output_put(&handle, mmap_event->min);
7649 perf_output_put(&handle, mmap_event->ino);
7650 perf_output_put(&handle, mmap_event->ino_generation);
7651 perf_output_put(&handle, mmap_event->prot);
7652 perf_output_put(&handle, mmap_event->flags);
7655 __output_copy(&handle, mmap_event->file_name,
7656 mmap_event->file_size);
7658 perf_event__output_id_sample(event, &handle, &sample);
7660 perf_output_end(&handle);
7662 mmap_event->event_id.header.size = size;
7663 mmap_event->event_id.header.type = type;
7666 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7668 struct vm_area_struct *vma = mmap_event->vma;
7669 struct file *file = vma->vm_file;
7670 int maj = 0, min = 0;
7671 u64 ino = 0, gen = 0;
7672 u32 prot = 0, flags = 0;
7678 if (vma->vm_flags & VM_READ)
7680 if (vma->vm_flags & VM_WRITE)
7682 if (vma->vm_flags & VM_EXEC)
7685 if (vma->vm_flags & VM_MAYSHARE)
7688 flags = MAP_PRIVATE;
7690 if (vma->vm_flags & VM_DENYWRITE)
7691 flags |= MAP_DENYWRITE;
7692 if (vma->vm_flags & VM_MAYEXEC)
7693 flags |= MAP_EXECUTABLE;
7694 if (vma->vm_flags & VM_LOCKED)
7695 flags |= MAP_LOCKED;
7696 if (vma->vm_flags & VM_HUGETLB)
7697 flags |= MAP_HUGETLB;
7700 struct inode *inode;
7703 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7709 * d_path() works from the end of the rb backwards, so we
7710 * need to add enough zero bytes after the string to handle
7711 * the 64bit alignment we do later.
7713 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7718 inode = file_inode(vma->vm_file);
7719 dev = inode->i_sb->s_dev;
7721 gen = inode->i_generation;
7727 if (vma->vm_ops && vma->vm_ops->name) {
7728 name = (char *) vma->vm_ops->name(vma);
7733 name = (char *)arch_vma_name(vma);
7737 if (vma->vm_start <= vma->vm_mm->start_brk &&
7738 vma->vm_end >= vma->vm_mm->brk) {
7742 if (vma->vm_start <= vma->vm_mm->start_stack &&
7743 vma->vm_end >= vma->vm_mm->start_stack) {
7753 strlcpy(tmp, name, sizeof(tmp));
7757 * Since our buffer works in 8 byte units we need to align our string
7758 * size to a multiple of 8. However, we must guarantee the tail end is
7759 * zero'd out to avoid leaking random bits to userspace.
7761 size = strlen(name)+1;
7762 while (!IS_ALIGNED(size, sizeof(u64)))
7763 name[size++] = '\0';
7765 mmap_event->file_name = name;
7766 mmap_event->file_size = size;
7767 mmap_event->maj = maj;
7768 mmap_event->min = min;
7769 mmap_event->ino = ino;
7770 mmap_event->ino_generation = gen;
7771 mmap_event->prot = prot;
7772 mmap_event->flags = flags;
7774 if (!(vma->vm_flags & VM_EXEC))
7775 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7777 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7779 perf_iterate_sb(perf_event_mmap_output,
7787 * Check whether inode and address range match filter criteria.
7789 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7790 struct file *file, unsigned long offset,
7793 /* d_inode(NULL) won't be equal to any mapped user-space file */
7794 if (!filter->path.dentry)
7797 if (d_inode(filter->path.dentry) != file_inode(file))
7800 if (filter->offset > offset + size)
7803 if (filter->offset + filter->size < offset)
7809 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7810 struct vm_area_struct *vma,
7811 struct perf_addr_filter_range *fr)
7813 unsigned long vma_size = vma->vm_end - vma->vm_start;
7814 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7815 struct file *file = vma->vm_file;
7817 if (!perf_addr_filter_match(filter, file, off, vma_size))
7820 if (filter->offset < off) {
7821 fr->start = vma->vm_start;
7822 fr->size = min(vma_size, filter->size - (off - filter->offset));
7824 fr->start = vma->vm_start + filter->offset - off;
7825 fr->size = min(vma->vm_end - fr->start, filter->size);
7831 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7833 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7834 struct vm_area_struct *vma = data;
7835 struct perf_addr_filter *filter;
7836 unsigned int restart = 0, count = 0;
7837 unsigned long flags;
7839 if (!has_addr_filter(event))
7845 raw_spin_lock_irqsave(&ifh->lock, flags);
7846 list_for_each_entry(filter, &ifh->list, entry) {
7847 if (perf_addr_filter_vma_adjust(filter, vma,
7848 &event->addr_filter_ranges[count]))
7855 event->addr_filters_gen++;
7856 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7859 perf_event_stop(event, 1);
7863 * Adjust all task's events' filters to the new vma
7865 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7867 struct perf_event_context *ctx;
7871 * Data tracing isn't supported yet and as such there is no need
7872 * to keep track of anything that isn't related to executable code:
7874 if (!(vma->vm_flags & VM_EXEC))
7878 for_each_task_context_nr(ctxn) {
7879 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7883 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7888 void perf_event_mmap(struct vm_area_struct *vma)
7890 struct perf_mmap_event mmap_event;
7892 if (!atomic_read(&nr_mmap_events))
7895 mmap_event = (struct perf_mmap_event){
7901 .type = PERF_RECORD_MMAP,
7902 .misc = PERF_RECORD_MISC_USER,
7907 .start = vma->vm_start,
7908 .len = vma->vm_end - vma->vm_start,
7909 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7911 /* .maj (attr_mmap2 only) */
7912 /* .min (attr_mmap2 only) */
7913 /* .ino (attr_mmap2 only) */
7914 /* .ino_generation (attr_mmap2 only) */
7915 /* .prot (attr_mmap2 only) */
7916 /* .flags (attr_mmap2 only) */
7919 perf_addr_filters_adjust(vma);
7920 perf_event_mmap_event(&mmap_event);
7923 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7924 unsigned long size, u64 flags)
7926 struct perf_output_handle handle;
7927 struct perf_sample_data sample;
7928 struct perf_aux_event {
7929 struct perf_event_header header;
7935 .type = PERF_RECORD_AUX,
7937 .size = sizeof(rec),
7945 perf_event_header__init_id(&rec.header, &sample, event);
7946 ret = perf_output_begin(&handle, event, rec.header.size);
7951 perf_output_put(&handle, rec);
7952 perf_event__output_id_sample(event, &handle, &sample);
7954 perf_output_end(&handle);
7958 * Lost/dropped samples logging
7960 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7962 struct perf_output_handle handle;
7963 struct perf_sample_data sample;
7967 struct perf_event_header header;
7969 } lost_samples_event = {
7971 .type = PERF_RECORD_LOST_SAMPLES,
7973 .size = sizeof(lost_samples_event),
7978 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7980 ret = perf_output_begin(&handle, event,
7981 lost_samples_event.header.size);
7985 perf_output_put(&handle, lost_samples_event);
7986 perf_event__output_id_sample(event, &handle, &sample);
7987 perf_output_end(&handle);
7991 * context_switch tracking
7994 struct perf_switch_event {
7995 struct task_struct *task;
7996 struct task_struct *next_prev;
7999 struct perf_event_header header;
8005 static int perf_event_switch_match(struct perf_event *event)
8007 return event->attr.context_switch;
8010 static void perf_event_switch_output(struct perf_event *event, void *data)
8012 struct perf_switch_event *se = data;
8013 struct perf_output_handle handle;
8014 struct perf_sample_data sample;
8017 if (!perf_event_switch_match(event))
8020 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8021 if (event->ctx->task) {
8022 se->event_id.header.type = PERF_RECORD_SWITCH;
8023 se->event_id.header.size = sizeof(se->event_id.header);
8025 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8026 se->event_id.header.size = sizeof(se->event_id);
8027 se->event_id.next_prev_pid =
8028 perf_event_pid(event, se->next_prev);
8029 se->event_id.next_prev_tid =
8030 perf_event_tid(event, se->next_prev);
8033 perf_event_header__init_id(&se->event_id.header, &sample, event);
8035 ret = perf_output_begin(&handle, event, se->event_id.header.size);
8039 if (event->ctx->task)
8040 perf_output_put(&handle, se->event_id.header);
8042 perf_output_put(&handle, se->event_id);
8044 perf_event__output_id_sample(event, &handle, &sample);
8046 perf_output_end(&handle);
8049 static void perf_event_switch(struct task_struct *task,
8050 struct task_struct *next_prev, bool sched_in)
8052 struct perf_switch_event switch_event;
8054 /* N.B. caller checks nr_switch_events != 0 */
8056 switch_event = (struct perf_switch_event){
8058 .next_prev = next_prev,
8062 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8065 /* .next_prev_pid */
8066 /* .next_prev_tid */
8070 if (!sched_in && task->state == TASK_RUNNING)
8071 switch_event.event_id.header.misc |=
8072 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8074 perf_iterate_sb(perf_event_switch_output,
8080 * IRQ throttle logging
8083 static void perf_log_throttle(struct perf_event *event, int enable)
8085 struct perf_output_handle handle;
8086 struct perf_sample_data sample;
8090 struct perf_event_header header;
8094 } throttle_event = {
8096 .type = PERF_RECORD_THROTTLE,
8098 .size = sizeof(throttle_event),
8100 .time = perf_event_clock(event),
8101 .id = primary_event_id(event),
8102 .stream_id = event->id,
8106 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8108 perf_event_header__init_id(&throttle_event.header, &sample, event);
8110 ret = perf_output_begin(&handle, event,
8111 throttle_event.header.size);
8115 perf_output_put(&handle, throttle_event);
8116 perf_event__output_id_sample(event, &handle, &sample);
8117 perf_output_end(&handle);
8121 * ksymbol register/unregister tracking
8124 struct perf_ksymbol_event {
8128 struct perf_event_header header;
8136 static int perf_event_ksymbol_match(struct perf_event *event)
8138 return event->attr.ksymbol;
8141 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8143 struct perf_ksymbol_event *ksymbol_event = data;
8144 struct perf_output_handle handle;
8145 struct perf_sample_data sample;
8148 if (!perf_event_ksymbol_match(event))
8151 perf_event_header__init_id(&ksymbol_event->event_id.header,
8153 ret = perf_output_begin(&handle, event,
8154 ksymbol_event->event_id.header.size);
8158 perf_output_put(&handle, ksymbol_event->event_id);
8159 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8160 perf_event__output_id_sample(event, &handle, &sample);
8162 perf_output_end(&handle);
8165 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8168 struct perf_ksymbol_event ksymbol_event;
8169 char name[KSYM_NAME_LEN];
8173 if (!atomic_read(&nr_ksymbol_events))
8176 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8177 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8180 strlcpy(name, sym, KSYM_NAME_LEN);
8181 name_len = strlen(name) + 1;
8182 while (!IS_ALIGNED(name_len, sizeof(u64)))
8183 name[name_len++] = '\0';
8184 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8187 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8189 ksymbol_event = (struct perf_ksymbol_event){
8191 .name_len = name_len,
8194 .type = PERF_RECORD_KSYMBOL,
8195 .size = sizeof(ksymbol_event.event_id) +
8200 .ksym_type = ksym_type,
8205 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8208 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8212 * bpf program load/unload tracking
8215 struct perf_bpf_event {
8216 struct bpf_prog *prog;
8218 struct perf_event_header header;
8222 u8 tag[BPF_TAG_SIZE];
8226 static int perf_event_bpf_match(struct perf_event *event)
8228 return event->attr.bpf_event;
8231 static void perf_event_bpf_output(struct perf_event *event, void *data)
8233 struct perf_bpf_event *bpf_event = data;
8234 struct perf_output_handle handle;
8235 struct perf_sample_data sample;
8238 if (!perf_event_bpf_match(event))
8241 perf_event_header__init_id(&bpf_event->event_id.header,
8243 ret = perf_output_begin(&handle, event,
8244 bpf_event->event_id.header.size);
8248 perf_output_put(&handle, bpf_event->event_id);
8249 perf_event__output_id_sample(event, &handle, &sample);
8251 perf_output_end(&handle);
8254 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8255 enum perf_bpf_event_type type)
8257 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8258 char sym[KSYM_NAME_LEN];
8261 if (prog->aux->func_cnt == 0) {
8262 bpf_get_prog_name(prog, sym);
8263 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8264 (u64)(unsigned long)prog->bpf_func,
8265 prog->jited_len, unregister, sym);
8267 for (i = 0; i < prog->aux->func_cnt; i++) {
8268 struct bpf_prog *subprog = prog->aux->func[i];
8270 bpf_get_prog_name(subprog, sym);
8272 PERF_RECORD_KSYMBOL_TYPE_BPF,
8273 (u64)(unsigned long)subprog->bpf_func,
8274 subprog->jited_len, unregister, sym);
8279 void perf_event_bpf_event(struct bpf_prog *prog,
8280 enum perf_bpf_event_type type,
8283 struct perf_bpf_event bpf_event;
8285 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8286 type >= PERF_BPF_EVENT_MAX)
8290 case PERF_BPF_EVENT_PROG_LOAD:
8291 case PERF_BPF_EVENT_PROG_UNLOAD:
8292 if (atomic_read(&nr_ksymbol_events))
8293 perf_event_bpf_emit_ksymbols(prog, type);
8299 if (!atomic_read(&nr_bpf_events))
8302 bpf_event = (struct perf_bpf_event){
8306 .type = PERF_RECORD_BPF_EVENT,
8307 .size = sizeof(bpf_event.event_id),
8311 .id = prog->aux->id,
8315 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8317 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8318 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8321 void perf_event_itrace_started(struct perf_event *event)
8323 event->attach_state |= PERF_ATTACH_ITRACE;
8326 static void perf_log_itrace_start(struct perf_event *event)
8328 struct perf_output_handle handle;
8329 struct perf_sample_data sample;
8330 struct perf_aux_event {
8331 struct perf_event_header header;
8338 event = event->parent;
8340 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8341 event->attach_state & PERF_ATTACH_ITRACE)
8344 rec.header.type = PERF_RECORD_ITRACE_START;
8345 rec.header.misc = 0;
8346 rec.header.size = sizeof(rec);
8347 rec.pid = perf_event_pid(event, current);
8348 rec.tid = perf_event_tid(event, current);
8350 perf_event_header__init_id(&rec.header, &sample, event);
8351 ret = perf_output_begin(&handle, event, rec.header.size);
8356 perf_output_put(&handle, rec);
8357 perf_event__output_id_sample(event, &handle, &sample);
8359 perf_output_end(&handle);
8363 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8365 struct hw_perf_event *hwc = &event->hw;
8369 seq = __this_cpu_read(perf_throttled_seq);
8370 if (seq != hwc->interrupts_seq) {
8371 hwc->interrupts_seq = seq;
8372 hwc->interrupts = 1;
8375 if (unlikely(throttle
8376 && hwc->interrupts >= max_samples_per_tick)) {
8377 __this_cpu_inc(perf_throttled_count);
8378 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8379 hwc->interrupts = MAX_INTERRUPTS;
8380 perf_log_throttle(event, 0);
8385 if (event->attr.freq) {
8386 u64 now = perf_clock();
8387 s64 delta = now - hwc->freq_time_stamp;
8389 hwc->freq_time_stamp = now;
8391 if (delta > 0 && delta < 2*TICK_NSEC)
8392 perf_adjust_period(event, delta, hwc->last_period, true);
8398 int perf_event_account_interrupt(struct perf_event *event)
8400 return __perf_event_account_interrupt(event, 1);
8404 * Generic event overflow handling, sampling.
8407 static int __perf_event_overflow(struct perf_event *event,
8408 int throttle, struct perf_sample_data *data,
8409 struct pt_regs *regs)
8411 int events = atomic_read(&event->event_limit);
8415 * Non-sampling counters might still use the PMI to fold short
8416 * hardware counters, ignore those.
8418 if (unlikely(!is_sampling_event(event)))
8421 ret = __perf_event_account_interrupt(event, throttle);
8424 * XXX event_limit might not quite work as expected on inherited
8428 event->pending_kill = POLL_IN;
8429 if (events && atomic_dec_and_test(&event->event_limit)) {
8431 event->pending_kill = POLL_HUP;
8433 perf_event_disable_inatomic(event);
8436 READ_ONCE(event->overflow_handler)(event, data, regs);
8438 if (*perf_event_fasync(event) && event->pending_kill) {
8439 event->pending_wakeup = 1;
8440 irq_work_queue(&event->pending);
8446 int perf_event_overflow(struct perf_event *event,
8447 struct perf_sample_data *data,
8448 struct pt_regs *regs)
8450 return __perf_event_overflow(event, 1, data, regs);
8454 * Generic software event infrastructure
8457 struct swevent_htable {
8458 struct swevent_hlist *swevent_hlist;
8459 struct mutex hlist_mutex;
8462 /* Recursion avoidance in each contexts */
8463 int recursion[PERF_NR_CONTEXTS];
8466 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8469 * We directly increment event->count and keep a second value in
8470 * event->hw.period_left to count intervals. This period event
8471 * is kept in the range [-sample_period, 0] so that we can use the
8475 u64 perf_swevent_set_period(struct perf_event *event)
8477 struct hw_perf_event *hwc = &event->hw;
8478 u64 period = hwc->last_period;
8482 hwc->last_period = hwc->sample_period;
8485 old = val = local64_read(&hwc->period_left);
8489 nr = div64_u64(period + val, period);
8490 offset = nr * period;
8492 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8498 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8499 struct perf_sample_data *data,
8500 struct pt_regs *regs)
8502 struct hw_perf_event *hwc = &event->hw;
8506 overflow = perf_swevent_set_period(event);
8508 if (hwc->interrupts == MAX_INTERRUPTS)
8511 for (; overflow; overflow--) {
8512 if (__perf_event_overflow(event, throttle,
8515 * We inhibit the overflow from happening when
8516 * hwc->interrupts == MAX_INTERRUPTS.
8524 static void perf_swevent_event(struct perf_event *event, u64 nr,
8525 struct perf_sample_data *data,
8526 struct pt_regs *regs)
8528 struct hw_perf_event *hwc = &event->hw;
8530 local64_add(nr, &event->count);
8535 if (!is_sampling_event(event))
8538 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8540 return perf_swevent_overflow(event, 1, data, regs);
8542 data->period = event->hw.last_period;
8544 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8545 return perf_swevent_overflow(event, 1, data, regs);
8547 if (local64_add_negative(nr, &hwc->period_left))
8550 perf_swevent_overflow(event, 0, data, regs);
8553 static int perf_exclude_event(struct perf_event *event,
8554 struct pt_regs *regs)
8556 if (event->hw.state & PERF_HES_STOPPED)
8560 if (event->attr.exclude_user && user_mode(regs))
8563 if (event->attr.exclude_kernel && !user_mode(regs))
8570 static int perf_swevent_match(struct perf_event *event,
8571 enum perf_type_id type,
8573 struct perf_sample_data *data,
8574 struct pt_regs *regs)
8576 if (event->attr.type != type)
8579 if (event->attr.config != event_id)
8582 if (perf_exclude_event(event, regs))
8588 static inline u64 swevent_hash(u64 type, u32 event_id)
8590 u64 val = event_id | (type << 32);
8592 return hash_64(val, SWEVENT_HLIST_BITS);
8595 static inline struct hlist_head *
8596 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8598 u64 hash = swevent_hash(type, event_id);
8600 return &hlist->heads[hash];
8603 /* For the read side: events when they trigger */
8604 static inline struct hlist_head *
8605 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8607 struct swevent_hlist *hlist;
8609 hlist = rcu_dereference(swhash->swevent_hlist);
8613 return __find_swevent_head(hlist, type, event_id);
8616 /* For the event head insertion and removal in the hlist */
8617 static inline struct hlist_head *
8618 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8620 struct swevent_hlist *hlist;
8621 u32 event_id = event->attr.config;
8622 u64 type = event->attr.type;
8625 * Event scheduling is always serialized against hlist allocation
8626 * and release. Which makes the protected version suitable here.
8627 * The context lock guarantees that.
8629 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8630 lockdep_is_held(&event->ctx->lock));
8634 return __find_swevent_head(hlist, type, event_id);
8637 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8639 struct perf_sample_data *data,
8640 struct pt_regs *regs)
8642 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8643 struct perf_event *event;
8644 struct hlist_head *head;
8647 head = find_swevent_head_rcu(swhash, type, event_id);
8651 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8652 if (perf_swevent_match(event, type, event_id, data, regs))
8653 perf_swevent_event(event, nr, data, regs);
8659 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8661 int perf_swevent_get_recursion_context(void)
8663 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8665 return get_recursion_context(swhash->recursion);
8667 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8669 void perf_swevent_put_recursion_context(int rctx)
8671 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8673 put_recursion_context(swhash->recursion, rctx);
8676 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8678 struct perf_sample_data data;
8680 if (WARN_ON_ONCE(!regs))
8683 perf_sample_data_init(&data, addr, 0);
8684 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8687 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8691 preempt_disable_notrace();
8692 rctx = perf_swevent_get_recursion_context();
8693 if (unlikely(rctx < 0))
8696 ___perf_sw_event(event_id, nr, regs, addr);
8698 perf_swevent_put_recursion_context(rctx);
8700 preempt_enable_notrace();
8703 static void perf_swevent_read(struct perf_event *event)
8707 static int perf_swevent_add(struct perf_event *event, int flags)
8709 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8710 struct hw_perf_event *hwc = &event->hw;
8711 struct hlist_head *head;
8713 if (is_sampling_event(event)) {
8714 hwc->last_period = hwc->sample_period;
8715 perf_swevent_set_period(event);
8718 hwc->state = !(flags & PERF_EF_START);
8720 head = find_swevent_head(swhash, event);
8721 if (WARN_ON_ONCE(!head))
8724 hlist_add_head_rcu(&event->hlist_entry, head);
8725 perf_event_update_userpage(event);
8730 static void perf_swevent_del(struct perf_event *event, int flags)
8732 hlist_del_rcu(&event->hlist_entry);
8735 static void perf_swevent_start(struct perf_event *event, int flags)
8737 event->hw.state = 0;
8740 static void perf_swevent_stop(struct perf_event *event, int flags)
8742 event->hw.state = PERF_HES_STOPPED;
8745 /* Deref the hlist from the update side */
8746 static inline struct swevent_hlist *
8747 swevent_hlist_deref(struct swevent_htable *swhash)
8749 return rcu_dereference_protected(swhash->swevent_hlist,
8750 lockdep_is_held(&swhash->hlist_mutex));
8753 static void swevent_hlist_release(struct swevent_htable *swhash)
8755 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8760 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8761 kfree_rcu(hlist, rcu_head);
8764 static void swevent_hlist_put_cpu(int cpu)
8766 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8768 mutex_lock(&swhash->hlist_mutex);
8770 if (!--swhash->hlist_refcount)
8771 swevent_hlist_release(swhash);
8773 mutex_unlock(&swhash->hlist_mutex);
8776 static void swevent_hlist_put(void)
8780 for_each_possible_cpu(cpu)
8781 swevent_hlist_put_cpu(cpu);
8784 static int swevent_hlist_get_cpu(int cpu)
8786 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8789 mutex_lock(&swhash->hlist_mutex);
8790 if (!swevent_hlist_deref(swhash) &&
8791 cpumask_test_cpu(cpu, perf_online_mask)) {
8792 struct swevent_hlist *hlist;
8794 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8799 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8801 swhash->hlist_refcount++;
8803 mutex_unlock(&swhash->hlist_mutex);
8808 static int swevent_hlist_get(void)
8810 int err, cpu, failed_cpu;
8812 mutex_lock(&pmus_lock);
8813 for_each_possible_cpu(cpu) {
8814 err = swevent_hlist_get_cpu(cpu);
8820 mutex_unlock(&pmus_lock);
8823 for_each_possible_cpu(cpu) {
8824 if (cpu == failed_cpu)
8826 swevent_hlist_put_cpu(cpu);
8828 mutex_unlock(&pmus_lock);
8832 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8834 static void sw_perf_event_destroy(struct perf_event *event)
8836 u64 event_id = event->attr.config;
8838 WARN_ON(event->parent);
8840 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8841 swevent_hlist_put();
8844 static int perf_swevent_init(struct perf_event *event)
8846 u64 event_id = event->attr.config;
8848 if (event->attr.type != PERF_TYPE_SOFTWARE)
8852 * no branch sampling for software events
8854 if (has_branch_stack(event))
8858 case PERF_COUNT_SW_CPU_CLOCK:
8859 case PERF_COUNT_SW_TASK_CLOCK:
8866 if (event_id >= PERF_COUNT_SW_MAX)
8869 if (!event->parent) {
8872 err = swevent_hlist_get();
8876 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8877 event->destroy = sw_perf_event_destroy;
8883 static struct pmu perf_swevent = {
8884 .task_ctx_nr = perf_sw_context,
8886 .capabilities = PERF_PMU_CAP_NO_NMI,
8888 .event_init = perf_swevent_init,
8889 .add = perf_swevent_add,
8890 .del = perf_swevent_del,
8891 .start = perf_swevent_start,
8892 .stop = perf_swevent_stop,
8893 .read = perf_swevent_read,
8896 #ifdef CONFIG_EVENT_TRACING
8898 static int perf_tp_filter_match(struct perf_event *event,
8899 struct perf_sample_data *data)
8901 void *record = data->raw->frag.data;
8903 /* only top level events have filters set */
8905 event = event->parent;
8907 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8912 static int perf_tp_event_match(struct perf_event *event,
8913 struct perf_sample_data *data,
8914 struct pt_regs *regs)
8916 if (event->hw.state & PERF_HES_STOPPED)
8919 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8921 if (event->attr.exclude_kernel && !user_mode(regs))
8924 if (!perf_tp_filter_match(event, data))
8930 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8931 struct trace_event_call *call, u64 count,
8932 struct pt_regs *regs, struct hlist_head *head,
8933 struct task_struct *task)
8935 if (bpf_prog_array_valid(call)) {
8936 *(struct pt_regs **)raw_data = regs;
8937 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8938 perf_swevent_put_recursion_context(rctx);
8942 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8945 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8947 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8948 struct pt_regs *regs, struct hlist_head *head, int rctx,
8949 struct task_struct *task)
8951 struct perf_sample_data data;
8952 struct perf_event *event;
8954 struct perf_raw_record raw = {
8961 perf_sample_data_init(&data, 0, 0);
8964 perf_trace_buf_update(record, event_type);
8966 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8967 if (perf_tp_event_match(event, &data, regs))
8968 perf_swevent_event(event, count, &data, regs);
8972 * If we got specified a target task, also iterate its context and
8973 * deliver this event there too.
8975 if (task && task != current) {
8976 struct perf_event_context *ctx;
8977 struct trace_entry *entry = record;
8980 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8984 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8985 if (event->cpu != smp_processor_id())
8987 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8989 if (event->attr.config != entry->type)
8991 if (perf_tp_event_match(event, &data, regs))
8992 perf_swevent_event(event, count, &data, regs);
8998 perf_swevent_put_recursion_context(rctx);
9000 EXPORT_SYMBOL_GPL(perf_tp_event);
9002 static void tp_perf_event_destroy(struct perf_event *event)
9004 perf_trace_destroy(event);
9007 static int perf_tp_event_init(struct perf_event *event)
9011 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9015 * no branch sampling for tracepoint events
9017 if (has_branch_stack(event))
9020 err = perf_trace_init(event);
9024 event->destroy = tp_perf_event_destroy;
9029 static struct pmu perf_tracepoint = {
9030 .task_ctx_nr = perf_sw_context,
9032 .event_init = perf_tp_event_init,
9033 .add = perf_trace_add,
9034 .del = perf_trace_del,
9035 .start = perf_swevent_start,
9036 .stop = perf_swevent_stop,
9037 .read = perf_swevent_read,
9040 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9042 * Flags in config, used by dynamic PMU kprobe and uprobe
9043 * The flags should match following PMU_FORMAT_ATTR().
9045 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9046 * if not set, create kprobe/uprobe
9048 * The following values specify a reference counter (or semaphore in the
9049 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9050 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9052 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9053 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9055 enum perf_probe_config {
9056 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9057 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9058 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9061 PMU_FORMAT_ATTR(retprobe, "config:0");
9064 #ifdef CONFIG_KPROBE_EVENTS
9065 static struct attribute *kprobe_attrs[] = {
9066 &format_attr_retprobe.attr,
9070 static struct attribute_group kprobe_format_group = {
9072 .attrs = kprobe_attrs,
9075 static const struct attribute_group *kprobe_attr_groups[] = {
9076 &kprobe_format_group,
9080 static int perf_kprobe_event_init(struct perf_event *event);
9081 static struct pmu perf_kprobe = {
9082 .task_ctx_nr = perf_sw_context,
9083 .event_init = perf_kprobe_event_init,
9084 .add = perf_trace_add,
9085 .del = perf_trace_del,
9086 .start = perf_swevent_start,
9087 .stop = perf_swevent_stop,
9088 .read = perf_swevent_read,
9089 .attr_groups = kprobe_attr_groups,
9092 static int perf_kprobe_event_init(struct perf_event *event)
9097 if (event->attr.type != perf_kprobe.type)
9100 if (!capable(CAP_SYS_ADMIN))
9104 * no branch sampling for probe events
9106 if (has_branch_stack(event))
9109 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9110 err = perf_kprobe_init(event, is_retprobe);
9114 event->destroy = perf_kprobe_destroy;
9118 #endif /* CONFIG_KPROBE_EVENTS */
9120 #ifdef CONFIG_UPROBE_EVENTS
9121 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9123 static struct attribute *uprobe_attrs[] = {
9124 &format_attr_retprobe.attr,
9125 &format_attr_ref_ctr_offset.attr,
9129 static struct attribute_group uprobe_format_group = {
9131 .attrs = uprobe_attrs,
9134 static const struct attribute_group *uprobe_attr_groups[] = {
9135 &uprobe_format_group,
9139 static int perf_uprobe_event_init(struct perf_event *event);
9140 static struct pmu perf_uprobe = {
9141 .task_ctx_nr = perf_sw_context,
9142 .event_init = perf_uprobe_event_init,
9143 .add = perf_trace_add,
9144 .del = perf_trace_del,
9145 .start = perf_swevent_start,
9146 .stop = perf_swevent_stop,
9147 .read = perf_swevent_read,
9148 .attr_groups = uprobe_attr_groups,
9151 static int perf_uprobe_event_init(struct perf_event *event)
9154 unsigned long ref_ctr_offset;
9157 if (event->attr.type != perf_uprobe.type)
9160 if (!capable(CAP_SYS_ADMIN))
9164 * no branch sampling for probe events
9166 if (has_branch_stack(event))
9169 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9170 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9171 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9175 event->destroy = perf_uprobe_destroy;
9179 #endif /* CONFIG_UPROBE_EVENTS */
9181 static inline void perf_tp_register(void)
9183 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9184 #ifdef CONFIG_KPROBE_EVENTS
9185 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9187 #ifdef CONFIG_UPROBE_EVENTS
9188 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9192 static void perf_event_free_filter(struct perf_event *event)
9194 ftrace_profile_free_filter(event);
9197 #ifdef CONFIG_BPF_SYSCALL
9198 static void bpf_overflow_handler(struct perf_event *event,
9199 struct perf_sample_data *data,
9200 struct pt_regs *regs)
9202 struct bpf_perf_event_data_kern ctx = {
9208 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9210 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9213 ret = BPF_PROG_RUN(event->prog, &ctx);
9216 __this_cpu_dec(bpf_prog_active);
9221 event->orig_overflow_handler(event, data, regs);
9224 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9226 struct bpf_prog *prog;
9228 if (event->overflow_handler_context)
9229 /* hw breakpoint or kernel counter */
9235 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9237 return PTR_ERR(prog);
9240 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9241 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9245 static void perf_event_free_bpf_handler(struct perf_event *event)
9247 struct bpf_prog *prog = event->prog;
9252 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9257 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9261 static void perf_event_free_bpf_handler(struct perf_event *event)
9267 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9268 * with perf_event_open()
9270 static inline bool perf_event_is_tracing(struct perf_event *event)
9272 if (event->pmu == &perf_tracepoint)
9274 #ifdef CONFIG_KPROBE_EVENTS
9275 if (event->pmu == &perf_kprobe)
9278 #ifdef CONFIG_UPROBE_EVENTS
9279 if (event->pmu == &perf_uprobe)
9285 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9287 bool is_kprobe, is_tracepoint, is_syscall_tp;
9288 struct bpf_prog *prog;
9291 if (!perf_event_is_tracing(event))
9292 return perf_event_set_bpf_handler(event, prog_fd);
9294 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9295 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9296 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9297 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9298 /* bpf programs can only be attached to u/kprobe or tracepoint */
9301 prog = bpf_prog_get(prog_fd);
9303 return PTR_ERR(prog);
9305 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9306 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9307 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9308 /* valid fd, but invalid bpf program type */
9313 /* Kprobe override only works for kprobes, not uprobes. */
9314 if (prog->kprobe_override &&
9315 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9320 if (is_tracepoint || is_syscall_tp) {
9321 int off = trace_event_get_offsets(event->tp_event);
9323 if (prog->aux->max_ctx_offset > off) {
9329 ret = perf_event_attach_bpf_prog(event, prog);
9335 static void perf_event_free_bpf_prog(struct perf_event *event)
9337 if (!perf_event_is_tracing(event)) {
9338 perf_event_free_bpf_handler(event);
9341 perf_event_detach_bpf_prog(event);
9346 static inline void perf_tp_register(void)
9350 static void perf_event_free_filter(struct perf_event *event)
9354 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9359 static void perf_event_free_bpf_prog(struct perf_event *event)
9362 #endif /* CONFIG_EVENT_TRACING */
9364 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9365 void perf_bp_event(struct perf_event *bp, void *data)
9367 struct perf_sample_data sample;
9368 struct pt_regs *regs = data;
9370 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9372 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9373 perf_swevent_event(bp, 1, &sample, regs);
9378 * Allocate a new address filter
9380 static struct perf_addr_filter *
9381 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9383 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9384 struct perf_addr_filter *filter;
9386 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9390 INIT_LIST_HEAD(&filter->entry);
9391 list_add_tail(&filter->entry, filters);
9396 static void free_filters_list(struct list_head *filters)
9398 struct perf_addr_filter *filter, *iter;
9400 list_for_each_entry_safe(filter, iter, filters, entry) {
9401 path_put(&filter->path);
9402 list_del(&filter->entry);
9408 * Free existing address filters and optionally install new ones
9410 static void perf_addr_filters_splice(struct perf_event *event,
9411 struct list_head *head)
9413 unsigned long flags;
9416 if (!has_addr_filter(event))
9419 /* don't bother with children, they don't have their own filters */
9423 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9425 list_splice_init(&event->addr_filters.list, &list);
9427 list_splice(head, &event->addr_filters.list);
9429 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9431 free_filters_list(&list);
9435 * Scan through mm's vmas and see if one of them matches the
9436 * @filter; if so, adjust filter's address range.
9437 * Called with mm::mmap_sem down for reading.
9439 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9440 struct mm_struct *mm,
9441 struct perf_addr_filter_range *fr)
9443 struct vm_area_struct *vma;
9445 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9449 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9455 * Update event's address range filters based on the
9456 * task's existing mappings, if any.
9458 static void perf_event_addr_filters_apply(struct perf_event *event)
9460 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9461 struct task_struct *task = READ_ONCE(event->ctx->task);
9462 struct perf_addr_filter *filter;
9463 struct mm_struct *mm = NULL;
9464 unsigned int count = 0;
9465 unsigned long flags;
9468 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9469 * will stop on the parent's child_mutex that our caller is also holding
9471 if (task == TASK_TOMBSTONE)
9474 if (ifh->nr_file_filters) {
9475 mm = get_task_mm(event->ctx->task);
9479 down_read(&mm->mmap_sem);
9482 raw_spin_lock_irqsave(&ifh->lock, flags);
9483 list_for_each_entry(filter, &ifh->list, entry) {
9484 if (filter->path.dentry) {
9486 * Adjust base offset if the filter is associated to a
9487 * binary that needs to be mapped:
9489 event->addr_filter_ranges[count].start = 0;
9490 event->addr_filter_ranges[count].size = 0;
9492 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9494 event->addr_filter_ranges[count].start = filter->offset;
9495 event->addr_filter_ranges[count].size = filter->size;
9501 event->addr_filters_gen++;
9502 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9504 if (ifh->nr_file_filters) {
9505 up_read(&mm->mmap_sem);
9511 perf_event_stop(event, 1);
9515 * Address range filtering: limiting the data to certain
9516 * instruction address ranges. Filters are ioctl()ed to us from
9517 * userspace as ascii strings.
9519 * Filter string format:
9522 * where ACTION is one of the
9523 * * "filter": limit the trace to this region
9524 * * "start": start tracing from this address
9525 * * "stop": stop tracing at this address/region;
9527 * * for kernel addresses: <start address>[/<size>]
9528 * * for object files: <start address>[/<size>]@</path/to/object/file>
9530 * if <size> is not specified or is zero, the range is treated as a single
9531 * address; not valid for ACTION=="filter".
9545 IF_STATE_ACTION = 0,
9550 static const match_table_t if_tokens = {
9551 { IF_ACT_FILTER, "filter" },
9552 { IF_ACT_START, "start" },
9553 { IF_ACT_STOP, "stop" },
9554 { IF_SRC_FILE, "%u/%u@%s" },
9555 { IF_SRC_KERNEL, "%u/%u" },
9556 { IF_SRC_FILEADDR, "%u@%s" },
9557 { IF_SRC_KERNELADDR, "%u" },
9558 { IF_ACT_NONE, NULL },
9562 * Address filter string parser
9565 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9566 struct list_head *filters)
9568 struct perf_addr_filter *filter = NULL;
9569 char *start, *orig, *filename = NULL;
9570 substring_t args[MAX_OPT_ARGS];
9571 int state = IF_STATE_ACTION, token;
9572 unsigned int kernel = 0;
9575 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9579 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9580 static const enum perf_addr_filter_action_t actions[] = {
9581 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9582 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9583 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9590 /* filter definition begins */
9591 if (state == IF_STATE_ACTION) {
9592 filter = perf_addr_filter_new(event, filters);
9597 token = match_token(start, if_tokens, args);
9602 if (state != IF_STATE_ACTION)
9605 filter->action = actions[token];
9606 state = IF_STATE_SOURCE;
9609 case IF_SRC_KERNELADDR:
9614 case IF_SRC_FILEADDR:
9616 if (state != IF_STATE_SOURCE)
9620 ret = kstrtoul(args[0].from, 0, &filter->offset);
9624 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9626 ret = kstrtoul(args[1].from, 0, &filter->size);
9631 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9632 int fpos = token == IF_SRC_FILE ? 2 : 1;
9634 filename = match_strdup(&args[fpos]);
9641 state = IF_STATE_END;
9649 * Filter definition is fully parsed, validate and install it.
9650 * Make sure that it doesn't contradict itself or the event's
9653 if (state == IF_STATE_END) {
9655 if (kernel && event->attr.exclude_kernel)
9659 * ACTION "filter" must have a non-zero length region
9662 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9671 * For now, we only support file-based filters
9672 * in per-task events; doing so for CPU-wide
9673 * events requires additional context switching
9674 * trickery, since same object code will be
9675 * mapped at different virtual addresses in
9676 * different processes.
9679 if (!event->ctx->task)
9680 goto fail_free_name;
9682 /* look up the path and grab its inode */
9683 ret = kern_path(filename, LOOKUP_FOLLOW,
9686 goto fail_free_name;
9692 if (!filter->path.dentry ||
9693 !S_ISREG(d_inode(filter->path.dentry)
9697 event->addr_filters.nr_file_filters++;
9700 /* ready to consume more filters */
9701 state = IF_STATE_ACTION;
9706 if (state != IF_STATE_ACTION)
9716 free_filters_list(filters);
9723 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9729 * Since this is called in perf_ioctl() path, we're already holding
9732 lockdep_assert_held(&event->ctx->mutex);
9734 if (WARN_ON_ONCE(event->parent))
9737 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9739 goto fail_clear_files;
9741 ret = event->pmu->addr_filters_validate(&filters);
9743 goto fail_free_filters;
9745 /* remove existing filters, if any */
9746 perf_addr_filters_splice(event, &filters);
9748 /* install new filters */
9749 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9754 free_filters_list(&filters);
9757 event->addr_filters.nr_file_filters = 0;
9762 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9767 filter_str = strndup_user(arg, PAGE_SIZE);
9768 if (IS_ERR(filter_str))
9769 return PTR_ERR(filter_str);
9771 #ifdef CONFIG_EVENT_TRACING
9772 if (perf_event_is_tracing(event)) {
9773 struct perf_event_context *ctx = event->ctx;
9776 * Beware, here be dragons!!
9778 * the tracepoint muck will deadlock against ctx->mutex, but
9779 * the tracepoint stuff does not actually need it. So
9780 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9781 * already have a reference on ctx.
9783 * This can result in event getting moved to a different ctx,
9784 * but that does not affect the tracepoint state.
9786 mutex_unlock(&ctx->mutex);
9787 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9788 mutex_lock(&ctx->mutex);
9791 if (has_addr_filter(event))
9792 ret = perf_event_set_addr_filter(event, filter_str);
9799 * hrtimer based swevent callback
9802 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9804 enum hrtimer_restart ret = HRTIMER_RESTART;
9805 struct perf_sample_data data;
9806 struct pt_regs *regs;
9807 struct perf_event *event;
9810 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9812 if (event->state != PERF_EVENT_STATE_ACTIVE)
9813 return HRTIMER_NORESTART;
9815 event->pmu->read(event);
9817 perf_sample_data_init(&data, 0, event->hw.last_period);
9818 regs = get_irq_regs();
9820 if (regs && !perf_exclude_event(event, regs)) {
9821 if (!(event->attr.exclude_idle && is_idle_task(current)))
9822 if (__perf_event_overflow(event, 1, &data, regs))
9823 ret = HRTIMER_NORESTART;
9826 period = max_t(u64, 10000, event->hw.sample_period);
9827 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9832 static void perf_swevent_start_hrtimer(struct perf_event *event)
9834 struct hw_perf_event *hwc = &event->hw;
9837 if (!is_sampling_event(event))
9840 period = local64_read(&hwc->period_left);
9845 local64_set(&hwc->period_left, 0);
9847 period = max_t(u64, 10000, hwc->sample_period);
9849 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9850 HRTIMER_MODE_REL_PINNED_HARD);
9853 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9855 struct hw_perf_event *hwc = &event->hw;
9857 if (is_sampling_event(event)) {
9858 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9859 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9861 hrtimer_cancel(&hwc->hrtimer);
9865 static void perf_swevent_init_hrtimer(struct perf_event *event)
9867 struct hw_perf_event *hwc = &event->hw;
9869 if (!is_sampling_event(event))
9872 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
9873 hwc->hrtimer.function = perf_swevent_hrtimer;
9876 * Since hrtimers have a fixed rate, we can do a static freq->period
9877 * mapping and avoid the whole period adjust feedback stuff.
9879 if (event->attr.freq) {
9880 long freq = event->attr.sample_freq;
9882 event->attr.sample_period = NSEC_PER_SEC / freq;
9883 hwc->sample_period = event->attr.sample_period;
9884 local64_set(&hwc->period_left, hwc->sample_period);
9885 hwc->last_period = hwc->sample_period;
9886 event->attr.freq = 0;
9891 * Software event: cpu wall time clock
9894 static void cpu_clock_event_update(struct perf_event *event)
9899 now = local_clock();
9900 prev = local64_xchg(&event->hw.prev_count, now);
9901 local64_add(now - prev, &event->count);
9904 static void cpu_clock_event_start(struct perf_event *event, int flags)
9906 local64_set(&event->hw.prev_count, local_clock());
9907 perf_swevent_start_hrtimer(event);
9910 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9912 perf_swevent_cancel_hrtimer(event);
9913 cpu_clock_event_update(event);
9916 static int cpu_clock_event_add(struct perf_event *event, int flags)
9918 if (flags & PERF_EF_START)
9919 cpu_clock_event_start(event, flags);
9920 perf_event_update_userpage(event);
9925 static void cpu_clock_event_del(struct perf_event *event, int flags)
9927 cpu_clock_event_stop(event, flags);
9930 static void cpu_clock_event_read(struct perf_event *event)
9932 cpu_clock_event_update(event);
9935 static int cpu_clock_event_init(struct perf_event *event)
9937 if (event->attr.type != PERF_TYPE_SOFTWARE)
9940 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9944 * no branch sampling for software events
9946 if (has_branch_stack(event))
9949 perf_swevent_init_hrtimer(event);
9954 static struct pmu perf_cpu_clock = {
9955 .task_ctx_nr = perf_sw_context,
9957 .capabilities = PERF_PMU_CAP_NO_NMI,
9959 .event_init = cpu_clock_event_init,
9960 .add = cpu_clock_event_add,
9961 .del = cpu_clock_event_del,
9962 .start = cpu_clock_event_start,
9963 .stop = cpu_clock_event_stop,
9964 .read = cpu_clock_event_read,
9968 * Software event: task time clock
9971 static void task_clock_event_update(struct perf_event *event, u64 now)
9976 prev = local64_xchg(&event->hw.prev_count, now);
9978 local64_add(delta, &event->count);
9981 static void task_clock_event_start(struct perf_event *event, int flags)
9983 local64_set(&event->hw.prev_count, event->ctx->time);
9984 perf_swevent_start_hrtimer(event);
9987 static void task_clock_event_stop(struct perf_event *event, int flags)
9989 perf_swevent_cancel_hrtimer(event);
9990 task_clock_event_update(event, event->ctx->time);
9993 static int task_clock_event_add(struct perf_event *event, int flags)
9995 if (flags & PERF_EF_START)
9996 task_clock_event_start(event, flags);
9997 perf_event_update_userpage(event);
10002 static void task_clock_event_del(struct perf_event *event, int flags)
10004 task_clock_event_stop(event, PERF_EF_UPDATE);
10007 static void task_clock_event_read(struct perf_event *event)
10009 u64 now = perf_clock();
10010 u64 delta = now - event->ctx->timestamp;
10011 u64 time = event->ctx->time + delta;
10013 task_clock_event_update(event, time);
10016 static int task_clock_event_init(struct perf_event *event)
10018 if (event->attr.type != PERF_TYPE_SOFTWARE)
10021 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10025 * no branch sampling for software events
10027 if (has_branch_stack(event))
10028 return -EOPNOTSUPP;
10030 perf_swevent_init_hrtimer(event);
10035 static struct pmu perf_task_clock = {
10036 .task_ctx_nr = perf_sw_context,
10038 .capabilities = PERF_PMU_CAP_NO_NMI,
10040 .event_init = task_clock_event_init,
10041 .add = task_clock_event_add,
10042 .del = task_clock_event_del,
10043 .start = task_clock_event_start,
10044 .stop = task_clock_event_stop,
10045 .read = task_clock_event_read,
10048 static void perf_pmu_nop_void(struct pmu *pmu)
10052 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10056 static int perf_pmu_nop_int(struct pmu *pmu)
10061 static int perf_event_nop_int(struct perf_event *event, u64 value)
10066 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10068 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10070 __this_cpu_write(nop_txn_flags, flags);
10072 if (flags & ~PERF_PMU_TXN_ADD)
10075 perf_pmu_disable(pmu);
10078 static int perf_pmu_commit_txn(struct pmu *pmu)
10080 unsigned int flags = __this_cpu_read(nop_txn_flags);
10082 __this_cpu_write(nop_txn_flags, 0);
10084 if (flags & ~PERF_PMU_TXN_ADD)
10087 perf_pmu_enable(pmu);
10091 static void perf_pmu_cancel_txn(struct pmu *pmu)
10093 unsigned int flags = __this_cpu_read(nop_txn_flags);
10095 __this_cpu_write(nop_txn_flags, 0);
10097 if (flags & ~PERF_PMU_TXN_ADD)
10100 perf_pmu_enable(pmu);
10103 static int perf_event_idx_default(struct perf_event *event)
10109 * Ensures all contexts with the same task_ctx_nr have the same
10110 * pmu_cpu_context too.
10112 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10119 list_for_each_entry(pmu, &pmus, entry) {
10120 if (pmu->task_ctx_nr == ctxn)
10121 return pmu->pmu_cpu_context;
10127 static void free_pmu_context(struct pmu *pmu)
10130 * Static contexts such as perf_sw_context have a global lifetime
10131 * and may be shared between different PMUs. Avoid freeing them
10132 * when a single PMU is going away.
10134 if (pmu->task_ctx_nr > perf_invalid_context)
10137 free_percpu(pmu->pmu_cpu_context);
10141 * Let userspace know that this PMU supports address range filtering:
10143 static ssize_t nr_addr_filters_show(struct device *dev,
10144 struct device_attribute *attr,
10147 struct pmu *pmu = dev_get_drvdata(dev);
10149 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10151 DEVICE_ATTR_RO(nr_addr_filters);
10153 static struct idr pmu_idr;
10156 type_show(struct device *dev, struct device_attribute *attr, char *page)
10158 struct pmu *pmu = dev_get_drvdata(dev);
10160 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10162 static DEVICE_ATTR_RO(type);
10165 perf_event_mux_interval_ms_show(struct device *dev,
10166 struct device_attribute *attr,
10169 struct pmu *pmu = dev_get_drvdata(dev);
10171 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10174 static DEFINE_MUTEX(mux_interval_mutex);
10177 perf_event_mux_interval_ms_store(struct device *dev,
10178 struct device_attribute *attr,
10179 const char *buf, size_t count)
10181 struct pmu *pmu = dev_get_drvdata(dev);
10182 int timer, cpu, ret;
10184 ret = kstrtoint(buf, 0, &timer);
10191 /* same value, noting to do */
10192 if (timer == pmu->hrtimer_interval_ms)
10195 mutex_lock(&mux_interval_mutex);
10196 pmu->hrtimer_interval_ms = timer;
10198 /* update all cpuctx for this PMU */
10200 for_each_online_cpu(cpu) {
10201 struct perf_cpu_context *cpuctx;
10202 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10203 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10205 cpu_function_call(cpu,
10206 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10208 cpus_read_unlock();
10209 mutex_unlock(&mux_interval_mutex);
10213 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10215 static struct attribute *pmu_dev_attrs[] = {
10216 &dev_attr_type.attr,
10217 &dev_attr_perf_event_mux_interval_ms.attr,
10220 ATTRIBUTE_GROUPS(pmu_dev);
10222 static int pmu_bus_running;
10223 static struct bus_type pmu_bus = {
10224 .name = "event_source",
10225 .dev_groups = pmu_dev_groups,
10228 static void pmu_dev_release(struct device *dev)
10233 static int pmu_dev_alloc(struct pmu *pmu)
10237 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10241 pmu->dev->groups = pmu->attr_groups;
10242 device_initialize(pmu->dev);
10243 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10247 dev_set_drvdata(pmu->dev, pmu);
10248 pmu->dev->bus = &pmu_bus;
10249 pmu->dev->release = pmu_dev_release;
10250 ret = device_add(pmu->dev);
10254 /* For PMUs with address filters, throw in an extra attribute: */
10255 if (pmu->nr_addr_filters)
10256 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10261 if (pmu->attr_update)
10262 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10271 device_del(pmu->dev);
10274 put_device(pmu->dev);
10278 static struct lock_class_key cpuctx_mutex;
10279 static struct lock_class_key cpuctx_lock;
10281 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10283 int cpu, ret, max = PERF_TYPE_MAX;
10285 mutex_lock(&pmus_lock);
10287 pmu->pmu_disable_count = alloc_percpu(int);
10288 if (!pmu->pmu_disable_count)
10296 if (type != PERF_TYPE_SOFTWARE) {
10300 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
10304 WARN_ON(type >= 0 && ret != type);
10310 if (pmu_bus_running) {
10311 ret = pmu_dev_alloc(pmu);
10317 if (pmu->task_ctx_nr == perf_hw_context) {
10318 static int hw_context_taken = 0;
10321 * Other than systems with heterogeneous CPUs, it never makes
10322 * sense for two PMUs to share perf_hw_context. PMUs which are
10323 * uncore must use perf_invalid_context.
10325 if (WARN_ON_ONCE(hw_context_taken &&
10326 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10327 pmu->task_ctx_nr = perf_invalid_context;
10329 hw_context_taken = 1;
10332 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10333 if (pmu->pmu_cpu_context)
10334 goto got_cpu_context;
10337 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10338 if (!pmu->pmu_cpu_context)
10341 for_each_possible_cpu(cpu) {
10342 struct perf_cpu_context *cpuctx;
10344 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10345 __perf_event_init_context(&cpuctx->ctx);
10346 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10347 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10348 cpuctx->ctx.pmu = pmu;
10349 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10351 __perf_mux_hrtimer_init(cpuctx, cpu);
10355 if (!pmu->start_txn) {
10356 if (pmu->pmu_enable) {
10358 * If we have pmu_enable/pmu_disable calls, install
10359 * transaction stubs that use that to try and batch
10360 * hardware accesses.
10362 pmu->start_txn = perf_pmu_start_txn;
10363 pmu->commit_txn = perf_pmu_commit_txn;
10364 pmu->cancel_txn = perf_pmu_cancel_txn;
10366 pmu->start_txn = perf_pmu_nop_txn;
10367 pmu->commit_txn = perf_pmu_nop_int;
10368 pmu->cancel_txn = perf_pmu_nop_void;
10372 if (!pmu->pmu_enable) {
10373 pmu->pmu_enable = perf_pmu_nop_void;
10374 pmu->pmu_disable = perf_pmu_nop_void;
10377 if (!pmu->check_period)
10378 pmu->check_period = perf_event_nop_int;
10380 if (!pmu->event_idx)
10381 pmu->event_idx = perf_event_idx_default;
10384 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
10385 * since these cannot be in the IDR. This way the linear search
10386 * is fast, provided a valid software event is provided.
10388 if (type == PERF_TYPE_SOFTWARE || !name)
10389 list_add_rcu(&pmu->entry, &pmus);
10391 list_add_tail_rcu(&pmu->entry, &pmus);
10393 atomic_set(&pmu->exclusive_cnt, 0);
10396 mutex_unlock(&pmus_lock);
10401 device_del(pmu->dev);
10402 put_device(pmu->dev);
10405 if (pmu->type != PERF_TYPE_SOFTWARE)
10406 idr_remove(&pmu_idr, pmu->type);
10409 free_percpu(pmu->pmu_disable_count);
10412 EXPORT_SYMBOL_GPL(perf_pmu_register);
10414 void perf_pmu_unregister(struct pmu *pmu)
10416 mutex_lock(&pmus_lock);
10417 list_del_rcu(&pmu->entry);
10420 * We dereference the pmu list under both SRCU and regular RCU, so
10421 * synchronize against both of those.
10423 synchronize_srcu(&pmus_srcu);
10426 free_percpu(pmu->pmu_disable_count);
10427 if (pmu->type != PERF_TYPE_SOFTWARE)
10428 idr_remove(&pmu_idr, pmu->type);
10429 if (pmu_bus_running) {
10430 if (pmu->nr_addr_filters)
10431 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10432 device_del(pmu->dev);
10433 put_device(pmu->dev);
10435 free_pmu_context(pmu);
10436 mutex_unlock(&pmus_lock);
10438 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10440 static inline bool has_extended_regs(struct perf_event *event)
10442 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10443 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10446 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10448 struct perf_event_context *ctx = NULL;
10451 if (!try_module_get(pmu->module))
10455 * A number of pmu->event_init() methods iterate the sibling_list to,
10456 * for example, validate if the group fits on the PMU. Therefore,
10457 * if this is a sibling event, acquire the ctx->mutex to protect
10458 * the sibling_list.
10460 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10462 * This ctx->mutex can nest when we're called through
10463 * inheritance. See the perf_event_ctx_lock_nested() comment.
10465 ctx = perf_event_ctx_lock_nested(event->group_leader,
10466 SINGLE_DEPTH_NESTING);
10471 ret = pmu->event_init(event);
10474 perf_event_ctx_unlock(event->group_leader, ctx);
10477 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10478 has_extended_regs(event))
10481 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10482 event_has_any_exclude_flag(event))
10485 if (ret && event->destroy)
10486 event->destroy(event);
10490 module_put(pmu->module);
10495 static struct pmu *perf_init_event(struct perf_event *event)
10497 int idx, type, ret;
10500 idx = srcu_read_lock(&pmus_srcu);
10502 /* Try parent's PMU first: */
10503 if (event->parent && event->parent->pmu) {
10504 pmu = event->parent->pmu;
10505 ret = perf_try_init_event(pmu, event);
10511 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
10512 * are often aliases for PERF_TYPE_RAW.
10514 type = event->attr.type;
10515 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
10516 type = PERF_TYPE_RAW;
10520 pmu = idr_find(&pmu_idr, type);
10523 ret = perf_try_init_event(pmu, event);
10524 if (ret == -ENOENT && event->attr.type != type) {
10525 type = event->attr.type;
10530 pmu = ERR_PTR(ret);
10535 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
10536 ret = perf_try_init_event(pmu, event);
10540 if (ret != -ENOENT) {
10541 pmu = ERR_PTR(ret);
10545 pmu = ERR_PTR(-ENOENT);
10547 srcu_read_unlock(&pmus_srcu, idx);
10552 static void attach_sb_event(struct perf_event *event)
10554 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10556 raw_spin_lock(&pel->lock);
10557 list_add_rcu(&event->sb_list, &pel->list);
10558 raw_spin_unlock(&pel->lock);
10562 * We keep a list of all !task (and therefore per-cpu) events
10563 * that need to receive side-band records.
10565 * This avoids having to scan all the various PMU per-cpu contexts
10566 * looking for them.
10568 static void account_pmu_sb_event(struct perf_event *event)
10570 if (is_sb_event(event))
10571 attach_sb_event(event);
10574 static void account_event_cpu(struct perf_event *event, int cpu)
10579 if (is_cgroup_event(event))
10580 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10583 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10584 static void account_freq_event_nohz(void)
10586 #ifdef CONFIG_NO_HZ_FULL
10587 /* Lock so we don't race with concurrent unaccount */
10588 spin_lock(&nr_freq_lock);
10589 if (atomic_inc_return(&nr_freq_events) == 1)
10590 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10591 spin_unlock(&nr_freq_lock);
10595 static void account_freq_event(void)
10597 if (tick_nohz_full_enabled())
10598 account_freq_event_nohz();
10600 atomic_inc(&nr_freq_events);
10604 static void account_event(struct perf_event *event)
10611 if (event->attach_state & PERF_ATTACH_TASK)
10613 if (event->attr.mmap || event->attr.mmap_data)
10614 atomic_inc(&nr_mmap_events);
10615 if (event->attr.comm)
10616 atomic_inc(&nr_comm_events);
10617 if (event->attr.namespaces)
10618 atomic_inc(&nr_namespaces_events);
10619 if (event->attr.task)
10620 atomic_inc(&nr_task_events);
10621 if (event->attr.freq)
10622 account_freq_event();
10623 if (event->attr.context_switch) {
10624 atomic_inc(&nr_switch_events);
10627 if (has_branch_stack(event))
10629 if (is_cgroup_event(event))
10631 if (event->attr.ksymbol)
10632 atomic_inc(&nr_ksymbol_events);
10633 if (event->attr.bpf_event)
10634 atomic_inc(&nr_bpf_events);
10638 * We need the mutex here because static_branch_enable()
10639 * must complete *before* the perf_sched_count increment
10642 if (atomic_inc_not_zero(&perf_sched_count))
10645 mutex_lock(&perf_sched_mutex);
10646 if (!atomic_read(&perf_sched_count)) {
10647 static_branch_enable(&perf_sched_events);
10649 * Guarantee that all CPUs observe they key change and
10650 * call the perf scheduling hooks before proceeding to
10651 * install events that need them.
10656 * Now that we have waited for the sync_sched(), allow further
10657 * increments to by-pass the mutex.
10659 atomic_inc(&perf_sched_count);
10660 mutex_unlock(&perf_sched_mutex);
10664 account_event_cpu(event, event->cpu);
10666 account_pmu_sb_event(event);
10670 * Allocate and initialize an event structure
10672 static struct perf_event *
10673 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10674 struct task_struct *task,
10675 struct perf_event *group_leader,
10676 struct perf_event *parent_event,
10677 perf_overflow_handler_t overflow_handler,
10678 void *context, int cgroup_fd)
10681 struct perf_event *event;
10682 struct hw_perf_event *hwc;
10683 long err = -EINVAL;
10685 if ((unsigned)cpu >= nr_cpu_ids) {
10686 if (!task || cpu != -1)
10687 return ERR_PTR(-EINVAL);
10690 event = kzalloc(sizeof(*event), GFP_KERNEL);
10692 return ERR_PTR(-ENOMEM);
10695 * Single events are their own group leaders, with an
10696 * empty sibling list:
10699 group_leader = event;
10701 mutex_init(&event->child_mutex);
10702 INIT_LIST_HEAD(&event->child_list);
10704 INIT_LIST_HEAD(&event->event_entry);
10705 INIT_LIST_HEAD(&event->sibling_list);
10706 INIT_LIST_HEAD(&event->active_list);
10707 init_event_group(event);
10708 INIT_LIST_HEAD(&event->rb_entry);
10709 INIT_LIST_HEAD(&event->active_entry);
10710 INIT_LIST_HEAD(&event->addr_filters.list);
10711 INIT_HLIST_NODE(&event->hlist_entry);
10714 init_waitqueue_head(&event->waitq);
10715 event->pending_disable = -1;
10716 init_irq_work(&event->pending, perf_pending_event);
10718 mutex_init(&event->mmap_mutex);
10719 raw_spin_lock_init(&event->addr_filters.lock);
10721 atomic_long_set(&event->refcount, 1);
10723 event->attr = *attr;
10724 event->group_leader = group_leader;
10728 event->parent = parent_event;
10730 event->ns = get_pid_ns(task_active_pid_ns(current));
10731 event->id = atomic64_inc_return(&perf_event_id);
10733 event->state = PERF_EVENT_STATE_INACTIVE;
10736 event->attach_state = PERF_ATTACH_TASK;
10738 * XXX pmu::event_init needs to know what task to account to
10739 * and we cannot use the ctx information because we need the
10740 * pmu before we get a ctx.
10742 event->hw.target = get_task_struct(task);
10745 event->clock = &local_clock;
10747 event->clock = parent_event->clock;
10749 if (!overflow_handler && parent_event) {
10750 overflow_handler = parent_event->overflow_handler;
10751 context = parent_event->overflow_handler_context;
10752 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10753 if (overflow_handler == bpf_overflow_handler) {
10754 struct bpf_prog *prog = parent_event->prog;
10756 bpf_prog_inc(prog);
10757 event->prog = prog;
10758 event->orig_overflow_handler =
10759 parent_event->orig_overflow_handler;
10764 if (overflow_handler) {
10765 event->overflow_handler = overflow_handler;
10766 event->overflow_handler_context = context;
10767 } else if (is_write_backward(event)){
10768 event->overflow_handler = perf_event_output_backward;
10769 event->overflow_handler_context = NULL;
10771 event->overflow_handler = perf_event_output_forward;
10772 event->overflow_handler_context = NULL;
10775 perf_event__state_init(event);
10780 hwc->sample_period = attr->sample_period;
10781 if (attr->freq && attr->sample_freq)
10782 hwc->sample_period = 1;
10783 hwc->last_period = hwc->sample_period;
10785 local64_set(&hwc->period_left, hwc->sample_period);
10788 * We currently do not support PERF_SAMPLE_READ on inherited events.
10789 * See perf_output_read().
10791 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10794 if (!has_branch_stack(event))
10795 event->attr.branch_sample_type = 0;
10797 if (cgroup_fd != -1) {
10798 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10803 pmu = perf_init_event(event);
10805 err = PTR_ERR(pmu);
10810 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
10811 * be different on other CPUs in the uncore mask.
10813 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
10818 if (event->attr.aux_output &&
10819 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10824 err = exclusive_event_init(event);
10828 if (has_addr_filter(event)) {
10829 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10830 sizeof(struct perf_addr_filter_range),
10832 if (!event->addr_filter_ranges) {
10838 * Clone the parent's vma offsets: they are valid until exec()
10839 * even if the mm is not shared with the parent.
10841 if (event->parent) {
10842 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10844 raw_spin_lock_irq(&ifh->lock);
10845 memcpy(event->addr_filter_ranges,
10846 event->parent->addr_filter_ranges,
10847 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10848 raw_spin_unlock_irq(&ifh->lock);
10851 /* force hw sync on the address filters */
10852 event->addr_filters_gen = 1;
10855 if (!event->parent) {
10856 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10857 err = get_callchain_buffers(attr->sample_max_stack);
10859 goto err_addr_filters;
10863 err = security_perf_event_alloc(event);
10865 goto err_callchain_buffer;
10867 /* symmetric to unaccount_event() in _free_event() */
10868 account_event(event);
10872 err_callchain_buffer:
10873 if (!event->parent) {
10874 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
10875 put_callchain_buffers();
10878 kfree(event->addr_filter_ranges);
10881 exclusive_event_destroy(event);
10884 if (event->destroy)
10885 event->destroy(event);
10886 module_put(pmu->module);
10888 if (is_cgroup_event(event))
10889 perf_detach_cgroup(event);
10891 put_pid_ns(event->ns);
10892 if (event->hw.target)
10893 put_task_struct(event->hw.target);
10896 return ERR_PTR(err);
10899 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10900 struct perf_event_attr *attr)
10905 /* Zero the full structure, so that a short copy will be nice. */
10906 memset(attr, 0, sizeof(*attr));
10908 ret = get_user(size, &uattr->size);
10912 /* ABI compatibility quirk: */
10914 size = PERF_ATTR_SIZE_VER0;
10915 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
10918 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
10927 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
10930 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10933 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10936 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10937 u64 mask = attr->branch_sample_type;
10939 /* only using defined bits */
10940 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10943 /* at least one branch bit must be set */
10944 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10947 /* propagate priv level, when not set for branch */
10948 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10950 /* exclude_kernel checked on syscall entry */
10951 if (!attr->exclude_kernel)
10952 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10954 if (!attr->exclude_user)
10955 mask |= PERF_SAMPLE_BRANCH_USER;
10957 if (!attr->exclude_hv)
10958 mask |= PERF_SAMPLE_BRANCH_HV;
10960 * adjust user setting (for HW filter setup)
10962 attr->branch_sample_type = mask;
10964 /* privileged levels capture (kernel, hv): check permissions */
10965 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
10966 ret = perf_allow_kernel(attr);
10972 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10973 ret = perf_reg_validate(attr->sample_regs_user);
10978 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10979 if (!arch_perf_have_user_stack_dump())
10983 * We have __u32 type for the size, but so far
10984 * we can only use __u16 as maximum due to the
10985 * __u16 sample size limit.
10987 if (attr->sample_stack_user >= USHRT_MAX)
10989 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10993 if (!attr->sample_max_stack)
10994 attr->sample_max_stack = sysctl_perf_event_max_stack;
10996 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10997 ret = perf_reg_validate(attr->sample_regs_intr);
11002 put_user(sizeof(*attr), &uattr->size);
11008 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11010 struct perf_buffer *rb = NULL;
11016 /* don't allow circular references */
11017 if (event == output_event)
11021 * Don't allow cross-cpu buffers
11023 if (output_event->cpu != event->cpu)
11027 * If its not a per-cpu rb, it must be the same task.
11029 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11033 * Mixing clocks in the same buffer is trouble you don't need.
11035 if (output_event->clock != event->clock)
11039 * Either writing ring buffer from beginning or from end.
11040 * Mixing is not allowed.
11042 if (is_write_backward(output_event) != is_write_backward(event))
11046 * If both events generate aux data, they must be on the same PMU
11048 if (has_aux(event) && has_aux(output_event) &&
11049 event->pmu != output_event->pmu)
11053 mutex_lock(&event->mmap_mutex);
11054 /* Can't redirect output if we've got an active mmap() */
11055 if (atomic_read(&event->mmap_count))
11058 if (output_event) {
11059 /* get the rb we want to redirect to */
11060 rb = ring_buffer_get(output_event);
11065 ring_buffer_attach(event, rb);
11069 mutex_unlock(&event->mmap_mutex);
11075 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11081 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11084 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11086 bool nmi_safe = false;
11089 case CLOCK_MONOTONIC:
11090 event->clock = &ktime_get_mono_fast_ns;
11094 case CLOCK_MONOTONIC_RAW:
11095 event->clock = &ktime_get_raw_fast_ns;
11099 case CLOCK_REALTIME:
11100 event->clock = &ktime_get_real_ns;
11103 case CLOCK_BOOTTIME:
11104 event->clock = &ktime_get_boottime_ns;
11108 event->clock = &ktime_get_clocktai_ns;
11115 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11122 * Variation on perf_event_ctx_lock_nested(), except we take two context
11125 static struct perf_event_context *
11126 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11127 struct perf_event_context *ctx)
11129 struct perf_event_context *gctx;
11133 gctx = READ_ONCE(group_leader->ctx);
11134 if (!refcount_inc_not_zero(&gctx->refcount)) {
11140 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11142 if (group_leader->ctx != gctx) {
11143 mutex_unlock(&ctx->mutex);
11144 mutex_unlock(&gctx->mutex);
11153 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11155 * @attr_uptr: event_id type attributes for monitoring/sampling
11158 * @group_fd: group leader event fd
11160 SYSCALL_DEFINE5(perf_event_open,
11161 struct perf_event_attr __user *, attr_uptr,
11162 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11164 struct perf_event *group_leader = NULL, *output_event = NULL;
11165 struct perf_event *event, *sibling;
11166 struct perf_event_attr attr;
11167 struct perf_event_context *ctx, *uninitialized_var(gctx);
11168 struct file *event_file = NULL;
11169 struct fd group = {NULL, 0};
11170 struct task_struct *task = NULL;
11173 int move_group = 0;
11175 int f_flags = O_RDWR;
11176 int cgroup_fd = -1;
11178 /* for future expandability... */
11179 if (flags & ~PERF_FLAG_ALL)
11182 /* Do we allow access to perf_event_open(2) ? */
11183 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11187 err = perf_copy_attr(attr_uptr, &attr);
11191 if (!attr.exclude_kernel) {
11192 err = perf_allow_kernel(&attr);
11197 if (attr.namespaces) {
11198 if (!capable(CAP_SYS_ADMIN))
11203 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11206 if (attr.sample_period & (1ULL << 63))
11210 /* Only privileged users can get physical addresses */
11211 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11212 err = perf_allow_kernel(&attr);
11217 err = security_locked_down(LOCKDOWN_PERF);
11218 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
11219 /* REGS_INTR can leak data, lockdown must prevent this */
11225 * In cgroup mode, the pid argument is used to pass the fd
11226 * opened to the cgroup directory in cgroupfs. The cpu argument
11227 * designates the cpu on which to monitor threads from that
11230 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
11233 if (flags & PERF_FLAG_FD_CLOEXEC)
11234 f_flags |= O_CLOEXEC;
11236 event_fd = get_unused_fd_flags(f_flags);
11240 if (group_fd != -1) {
11241 err = perf_fget_light(group_fd, &group);
11244 group_leader = group.file->private_data;
11245 if (flags & PERF_FLAG_FD_OUTPUT)
11246 output_event = group_leader;
11247 if (flags & PERF_FLAG_FD_NO_GROUP)
11248 group_leader = NULL;
11251 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
11252 task = find_lively_task_by_vpid(pid);
11253 if (IS_ERR(task)) {
11254 err = PTR_ERR(task);
11259 if (task && group_leader &&
11260 group_leader->attr.inherit != attr.inherit) {
11266 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
11271 * Reuse ptrace permission checks for now.
11273 * We must hold cred_guard_mutex across this and any potential
11274 * perf_install_in_context() call for this new event to
11275 * serialize against exec() altering our credentials (and the
11276 * perf_event_exit_task() that could imply).
11279 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
11283 if (flags & PERF_FLAG_PID_CGROUP)
11286 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11287 NULL, NULL, cgroup_fd);
11288 if (IS_ERR(event)) {
11289 err = PTR_ERR(event);
11293 if (is_sampling_event(event)) {
11294 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11301 * Special case software events and allow them to be part of
11302 * any hardware group.
11306 if (attr.use_clockid) {
11307 err = perf_event_set_clock(event, attr.clockid);
11312 if (pmu->task_ctx_nr == perf_sw_context)
11313 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11315 if (group_leader) {
11316 if (is_software_event(event) &&
11317 !in_software_context(group_leader)) {
11319 * If the event is a sw event, but the group_leader
11320 * is on hw context.
11322 * Allow the addition of software events to hw
11323 * groups, this is safe because software events
11324 * never fail to schedule.
11326 pmu = group_leader->ctx->pmu;
11327 } else if (!is_software_event(event) &&
11328 is_software_event(group_leader) &&
11329 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11331 * In case the group is a pure software group, and we
11332 * try to add a hardware event, move the whole group to
11333 * the hardware context.
11340 * Get the target context (task or percpu):
11342 ctx = find_get_context(pmu, task, event);
11344 err = PTR_ERR(ctx);
11349 * Look up the group leader (we will attach this event to it):
11351 if (group_leader) {
11355 * Do not allow a recursive hierarchy (this new sibling
11356 * becoming part of another group-sibling):
11358 if (group_leader->group_leader != group_leader)
11361 /* All events in a group should have the same clock */
11362 if (group_leader->clock != event->clock)
11366 * Make sure we're both events for the same CPU;
11367 * grouping events for different CPUs is broken; since
11368 * you can never concurrently schedule them anyhow.
11370 if (group_leader->cpu != event->cpu)
11374 * Make sure we're both on the same task, or both
11377 if (group_leader->ctx->task != ctx->task)
11381 * Do not allow to attach to a group in a different task
11382 * or CPU context. If we're moving SW events, we'll fix
11383 * this up later, so allow that.
11385 if (!move_group && group_leader->ctx != ctx)
11389 * Only a group leader can be exclusive or pinned
11391 if (attr.exclusive || attr.pinned)
11395 if (output_event) {
11396 err = perf_event_set_output(event, output_event);
11401 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11403 if (IS_ERR(event_file)) {
11404 err = PTR_ERR(event_file);
11410 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11412 if (gctx->task == TASK_TOMBSTONE) {
11418 * Check if we raced against another sys_perf_event_open() call
11419 * moving the software group underneath us.
11421 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11423 * If someone moved the group out from under us, check
11424 * if this new event wound up on the same ctx, if so
11425 * its the regular !move_group case, otherwise fail.
11431 perf_event_ctx_unlock(group_leader, gctx);
11437 * Failure to create exclusive events returns -EBUSY.
11440 if (!exclusive_event_installable(group_leader, ctx))
11443 for_each_sibling_event(sibling, group_leader) {
11444 if (!exclusive_event_installable(sibling, ctx))
11448 mutex_lock(&ctx->mutex);
11451 if (ctx->task == TASK_TOMBSTONE) {
11456 if (!perf_event_validate_size(event)) {
11463 * Check if the @cpu we're creating an event for is online.
11465 * We use the perf_cpu_context::ctx::mutex to serialize against
11466 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11468 struct perf_cpu_context *cpuctx =
11469 container_of(ctx, struct perf_cpu_context, ctx);
11471 if (!cpuctx->online) {
11477 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
11483 * Must be under the same ctx::mutex as perf_install_in_context(),
11484 * because we need to serialize with concurrent event creation.
11486 if (!exclusive_event_installable(event, ctx)) {
11491 WARN_ON_ONCE(ctx->parent_ctx);
11494 * This is the point on no return; we cannot fail hereafter. This is
11495 * where we start modifying current state.
11500 * See perf_event_ctx_lock() for comments on the details
11501 * of swizzling perf_event::ctx.
11503 perf_remove_from_context(group_leader, 0);
11506 for_each_sibling_event(sibling, group_leader) {
11507 perf_remove_from_context(sibling, 0);
11512 * Wait for everybody to stop referencing the events through
11513 * the old lists, before installing it on new lists.
11518 * Install the group siblings before the group leader.
11520 * Because a group leader will try and install the entire group
11521 * (through the sibling list, which is still in-tact), we can
11522 * end up with siblings installed in the wrong context.
11524 * By installing siblings first we NO-OP because they're not
11525 * reachable through the group lists.
11527 for_each_sibling_event(sibling, group_leader) {
11528 perf_event__state_init(sibling);
11529 perf_install_in_context(ctx, sibling, sibling->cpu);
11534 * Removing from the context ends up with disabled
11535 * event. What we want here is event in the initial
11536 * startup state, ready to be add into new context.
11538 perf_event__state_init(group_leader);
11539 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11544 * Precalculate sample_data sizes; do while holding ctx::mutex such
11545 * that we're serialized against further additions and before
11546 * perf_install_in_context() which is the point the event is active and
11547 * can use these values.
11549 perf_event__header_size(event);
11550 perf_event__id_header_size(event);
11552 event->owner = current;
11554 perf_install_in_context(ctx, event, event->cpu);
11555 perf_unpin_context(ctx);
11558 perf_event_ctx_unlock(group_leader, gctx);
11559 mutex_unlock(&ctx->mutex);
11562 mutex_unlock(&task->signal->cred_guard_mutex);
11563 put_task_struct(task);
11566 mutex_lock(¤t->perf_event_mutex);
11567 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11568 mutex_unlock(¤t->perf_event_mutex);
11571 * Drop the reference on the group_event after placing the
11572 * new event on the sibling_list. This ensures destruction
11573 * of the group leader will find the pointer to itself in
11574 * perf_group_detach().
11577 fd_install(event_fd, event_file);
11582 perf_event_ctx_unlock(group_leader, gctx);
11583 mutex_unlock(&ctx->mutex);
11587 perf_unpin_context(ctx);
11591 * If event_file is set, the fput() above will have called ->release()
11592 * and that will take care of freeing the event.
11598 mutex_unlock(&task->signal->cred_guard_mutex);
11601 put_task_struct(task);
11605 put_unused_fd(event_fd);
11610 * perf_event_create_kernel_counter
11612 * @attr: attributes of the counter to create
11613 * @cpu: cpu in which the counter is bound
11614 * @task: task to profile (NULL for percpu)
11616 struct perf_event *
11617 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11618 struct task_struct *task,
11619 perf_overflow_handler_t overflow_handler,
11622 struct perf_event_context *ctx;
11623 struct perf_event *event;
11627 * Grouping is not supported for kernel events, neither is 'AUX',
11628 * make sure the caller's intentions are adjusted.
11630 if (attr->aux_output)
11631 return ERR_PTR(-EINVAL);
11633 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11634 overflow_handler, context, -1);
11635 if (IS_ERR(event)) {
11636 err = PTR_ERR(event);
11640 /* Mark owner so we could distinguish it from user events. */
11641 event->owner = TASK_TOMBSTONE;
11644 * Get the target context (task or percpu):
11646 ctx = find_get_context(event->pmu, task, event);
11648 err = PTR_ERR(ctx);
11652 WARN_ON_ONCE(ctx->parent_ctx);
11653 mutex_lock(&ctx->mutex);
11654 if (ctx->task == TASK_TOMBSTONE) {
11661 * Check if the @cpu we're creating an event for is online.
11663 * We use the perf_cpu_context::ctx::mutex to serialize against
11664 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11666 struct perf_cpu_context *cpuctx =
11667 container_of(ctx, struct perf_cpu_context, ctx);
11668 if (!cpuctx->online) {
11674 if (!exclusive_event_installable(event, ctx)) {
11679 perf_install_in_context(ctx, event, event->cpu);
11680 perf_unpin_context(ctx);
11681 mutex_unlock(&ctx->mutex);
11686 mutex_unlock(&ctx->mutex);
11687 perf_unpin_context(ctx);
11692 return ERR_PTR(err);
11694 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11696 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11698 struct perf_event_context *src_ctx;
11699 struct perf_event_context *dst_ctx;
11700 struct perf_event *event, *tmp;
11703 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11704 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11707 * See perf_event_ctx_lock() for comments on the details
11708 * of swizzling perf_event::ctx.
11710 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11711 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11713 perf_remove_from_context(event, 0);
11714 unaccount_event_cpu(event, src_cpu);
11716 list_add(&event->migrate_entry, &events);
11720 * Wait for the events to quiesce before re-instating them.
11725 * Re-instate events in 2 passes.
11727 * Skip over group leaders and only install siblings on this first
11728 * pass, siblings will not get enabled without a leader, however a
11729 * leader will enable its siblings, even if those are still on the old
11732 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11733 if (event->group_leader == event)
11736 list_del(&event->migrate_entry);
11737 if (event->state >= PERF_EVENT_STATE_OFF)
11738 event->state = PERF_EVENT_STATE_INACTIVE;
11739 account_event_cpu(event, dst_cpu);
11740 perf_install_in_context(dst_ctx, event, dst_cpu);
11745 * Once all the siblings are setup properly, install the group leaders
11748 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11749 list_del(&event->migrate_entry);
11750 if (event->state >= PERF_EVENT_STATE_OFF)
11751 event->state = PERF_EVENT_STATE_INACTIVE;
11752 account_event_cpu(event, dst_cpu);
11753 perf_install_in_context(dst_ctx, event, dst_cpu);
11756 mutex_unlock(&dst_ctx->mutex);
11757 mutex_unlock(&src_ctx->mutex);
11759 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11761 static void sync_child_event(struct perf_event *child_event,
11762 struct task_struct *child)
11764 struct perf_event *parent_event = child_event->parent;
11767 if (child_event->attr.inherit_stat)
11768 perf_event_read_event(child_event, child);
11770 child_val = perf_event_count(child_event);
11773 * Add back the child's count to the parent's count:
11775 atomic64_add(child_val, &parent_event->child_count);
11776 atomic64_add(child_event->total_time_enabled,
11777 &parent_event->child_total_time_enabled);
11778 atomic64_add(child_event->total_time_running,
11779 &parent_event->child_total_time_running);
11783 perf_event_exit_event(struct perf_event *child_event,
11784 struct perf_event_context *child_ctx,
11785 struct task_struct *child)
11787 struct perf_event *parent_event = child_event->parent;
11790 * Do not destroy the 'original' grouping; because of the context
11791 * switch optimization the original events could've ended up in a
11792 * random child task.
11794 * If we were to destroy the original group, all group related
11795 * operations would cease to function properly after this random
11798 * Do destroy all inherited groups, we don't care about those
11799 * and being thorough is better.
11801 raw_spin_lock_irq(&child_ctx->lock);
11802 WARN_ON_ONCE(child_ctx->is_active);
11805 perf_group_detach(child_event);
11806 list_del_event(child_event, child_ctx);
11807 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11808 raw_spin_unlock_irq(&child_ctx->lock);
11811 * Parent events are governed by their filedesc, retain them.
11813 if (!parent_event) {
11814 perf_event_wakeup(child_event);
11818 * Child events can be cleaned up.
11821 sync_child_event(child_event, child);
11824 * Remove this event from the parent's list
11826 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11827 mutex_lock(&parent_event->child_mutex);
11828 list_del_init(&child_event->child_list);
11829 mutex_unlock(&parent_event->child_mutex);
11832 * Kick perf_poll() for is_event_hup().
11834 perf_event_wakeup(parent_event);
11835 free_event(child_event);
11836 put_event(parent_event);
11839 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11841 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11842 struct perf_event *child_event, *next;
11844 WARN_ON_ONCE(child != current);
11846 child_ctx = perf_pin_task_context(child, ctxn);
11851 * In order to reduce the amount of tricky in ctx tear-down, we hold
11852 * ctx::mutex over the entire thing. This serializes against almost
11853 * everything that wants to access the ctx.
11855 * The exception is sys_perf_event_open() /
11856 * perf_event_create_kernel_count() which does find_get_context()
11857 * without ctx::mutex (it cannot because of the move_group double mutex
11858 * lock thing). See the comments in perf_install_in_context().
11860 mutex_lock(&child_ctx->mutex);
11863 * In a single ctx::lock section, de-schedule the events and detach the
11864 * context from the task such that we cannot ever get it scheduled back
11867 raw_spin_lock_irq(&child_ctx->lock);
11868 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11871 * Now that the context is inactive, destroy the task <-> ctx relation
11872 * and mark the context dead.
11874 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11875 put_ctx(child_ctx); /* cannot be last */
11876 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11877 put_task_struct(current); /* cannot be last */
11879 clone_ctx = unclone_ctx(child_ctx);
11880 raw_spin_unlock_irq(&child_ctx->lock);
11883 put_ctx(clone_ctx);
11886 * Report the task dead after unscheduling the events so that we
11887 * won't get any samples after PERF_RECORD_EXIT. We can however still
11888 * get a few PERF_RECORD_READ events.
11890 perf_event_task(child, child_ctx, 0);
11892 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11893 perf_event_exit_event(child_event, child_ctx, child);
11895 mutex_unlock(&child_ctx->mutex);
11897 put_ctx(child_ctx);
11901 * When a child task exits, feed back event values to parent events.
11903 * Can be called with cred_guard_mutex held when called from
11904 * install_exec_creds().
11906 void perf_event_exit_task(struct task_struct *child)
11908 struct perf_event *event, *tmp;
11911 mutex_lock(&child->perf_event_mutex);
11912 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11914 list_del_init(&event->owner_entry);
11917 * Ensure the list deletion is visible before we clear
11918 * the owner, closes a race against perf_release() where
11919 * we need to serialize on the owner->perf_event_mutex.
11921 smp_store_release(&event->owner, NULL);
11923 mutex_unlock(&child->perf_event_mutex);
11925 for_each_task_context_nr(ctxn)
11926 perf_event_exit_task_context(child, ctxn);
11929 * The perf_event_exit_task_context calls perf_event_task
11930 * with child's task_ctx, which generates EXIT events for
11931 * child contexts and sets child->perf_event_ctxp[] to NULL.
11932 * At this point we need to send EXIT events to cpu contexts.
11934 perf_event_task(child, NULL, 0);
11937 static void perf_free_event(struct perf_event *event,
11938 struct perf_event_context *ctx)
11940 struct perf_event *parent = event->parent;
11942 if (WARN_ON_ONCE(!parent))
11945 mutex_lock(&parent->child_mutex);
11946 list_del_init(&event->child_list);
11947 mutex_unlock(&parent->child_mutex);
11951 raw_spin_lock_irq(&ctx->lock);
11952 perf_group_detach(event);
11953 list_del_event(event, ctx);
11954 raw_spin_unlock_irq(&ctx->lock);
11959 * Free a context as created by inheritance by perf_event_init_task() below,
11960 * used by fork() in case of fail.
11962 * Even though the task has never lived, the context and events have been
11963 * exposed through the child_list, so we must take care tearing it all down.
11965 void perf_event_free_task(struct task_struct *task)
11967 struct perf_event_context *ctx;
11968 struct perf_event *event, *tmp;
11971 for_each_task_context_nr(ctxn) {
11972 ctx = task->perf_event_ctxp[ctxn];
11976 mutex_lock(&ctx->mutex);
11977 raw_spin_lock_irq(&ctx->lock);
11979 * Destroy the task <-> ctx relation and mark the context dead.
11981 * This is important because even though the task hasn't been
11982 * exposed yet the context has been (through child_list).
11984 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11985 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11986 put_task_struct(task); /* cannot be last */
11987 raw_spin_unlock_irq(&ctx->lock);
11989 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11990 perf_free_event(event, ctx);
11992 mutex_unlock(&ctx->mutex);
11995 * perf_event_release_kernel() could've stolen some of our
11996 * child events and still have them on its free_list. In that
11997 * case we must wait for these events to have been freed (in
11998 * particular all their references to this task must've been
12001 * Without this copy_process() will unconditionally free this
12002 * task (irrespective of its reference count) and
12003 * _free_event()'s put_task_struct(event->hw.target) will be a
12006 * Wait for all events to drop their context reference.
12008 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12009 put_ctx(ctx); /* must be last */
12013 void perf_event_delayed_put(struct task_struct *task)
12017 for_each_task_context_nr(ctxn)
12018 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12021 struct file *perf_event_get(unsigned int fd)
12023 struct file *file = fget(fd);
12025 return ERR_PTR(-EBADF);
12027 if (file->f_op != &perf_fops) {
12029 return ERR_PTR(-EBADF);
12035 const struct perf_event *perf_get_event(struct file *file)
12037 if (file->f_op != &perf_fops)
12038 return ERR_PTR(-EINVAL);
12040 return file->private_data;
12043 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12046 return ERR_PTR(-EINVAL);
12048 return &event->attr;
12052 * Inherit an event from parent task to child task.
12055 * - valid pointer on success
12056 * - NULL for orphaned events
12057 * - IS_ERR() on error
12059 static struct perf_event *
12060 inherit_event(struct perf_event *parent_event,
12061 struct task_struct *parent,
12062 struct perf_event_context *parent_ctx,
12063 struct task_struct *child,
12064 struct perf_event *group_leader,
12065 struct perf_event_context *child_ctx)
12067 enum perf_event_state parent_state = parent_event->state;
12068 struct perf_event *child_event;
12069 unsigned long flags;
12072 * Instead of creating recursive hierarchies of events,
12073 * we link inherited events back to the original parent,
12074 * which has a filp for sure, which we use as the reference
12077 if (parent_event->parent)
12078 parent_event = parent_event->parent;
12080 child_event = perf_event_alloc(&parent_event->attr,
12083 group_leader, parent_event,
12085 if (IS_ERR(child_event))
12086 return child_event;
12089 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12090 !child_ctx->task_ctx_data) {
12091 struct pmu *pmu = child_event->pmu;
12093 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
12095 if (!child_ctx->task_ctx_data) {
12096 free_event(child_event);
12097 return ERR_PTR(-ENOMEM);
12102 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12103 * must be under the same lock in order to serialize against
12104 * perf_event_release_kernel(), such that either we must observe
12105 * is_orphaned_event() or they will observe us on the child_list.
12107 mutex_lock(&parent_event->child_mutex);
12108 if (is_orphaned_event(parent_event) ||
12109 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12110 mutex_unlock(&parent_event->child_mutex);
12111 /* task_ctx_data is freed with child_ctx */
12112 free_event(child_event);
12116 get_ctx(child_ctx);
12119 * Make the child state follow the state of the parent event,
12120 * not its attr.disabled bit. We hold the parent's mutex,
12121 * so we won't race with perf_event_{en, dis}able_family.
12123 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12124 child_event->state = PERF_EVENT_STATE_INACTIVE;
12126 child_event->state = PERF_EVENT_STATE_OFF;
12128 if (parent_event->attr.freq) {
12129 u64 sample_period = parent_event->hw.sample_period;
12130 struct hw_perf_event *hwc = &child_event->hw;
12132 hwc->sample_period = sample_period;
12133 hwc->last_period = sample_period;
12135 local64_set(&hwc->period_left, sample_period);
12138 child_event->ctx = child_ctx;
12139 child_event->overflow_handler = parent_event->overflow_handler;
12140 child_event->overflow_handler_context
12141 = parent_event->overflow_handler_context;
12144 * Precalculate sample_data sizes
12146 perf_event__header_size(child_event);
12147 perf_event__id_header_size(child_event);
12150 * Link it up in the child's context:
12152 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12153 add_event_to_ctx(child_event, child_ctx);
12154 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12157 * Link this into the parent event's child list
12159 list_add_tail(&child_event->child_list, &parent_event->child_list);
12160 mutex_unlock(&parent_event->child_mutex);
12162 return child_event;
12166 * Inherits an event group.
12168 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12169 * This matches with perf_event_release_kernel() removing all child events.
12175 static int inherit_group(struct perf_event *parent_event,
12176 struct task_struct *parent,
12177 struct perf_event_context *parent_ctx,
12178 struct task_struct *child,
12179 struct perf_event_context *child_ctx)
12181 struct perf_event *leader;
12182 struct perf_event *sub;
12183 struct perf_event *child_ctr;
12185 leader = inherit_event(parent_event, parent, parent_ctx,
12186 child, NULL, child_ctx);
12187 if (IS_ERR(leader))
12188 return PTR_ERR(leader);
12190 * @leader can be NULL here because of is_orphaned_event(). In this
12191 * case inherit_event() will create individual events, similar to what
12192 * perf_group_detach() would do anyway.
12194 for_each_sibling_event(sub, parent_event) {
12195 child_ctr = inherit_event(sub, parent, parent_ctx,
12196 child, leader, child_ctx);
12197 if (IS_ERR(child_ctr))
12198 return PTR_ERR(child_ctr);
12200 if (sub->aux_event == parent_event && child_ctr &&
12201 !perf_get_aux_event(child_ctr, leader))
12208 * Creates the child task context and tries to inherit the event-group.
12210 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12211 * inherited_all set when we 'fail' to inherit an orphaned event; this is
12212 * consistent with perf_event_release_kernel() removing all child events.
12219 inherit_task_group(struct perf_event *event, struct task_struct *parent,
12220 struct perf_event_context *parent_ctx,
12221 struct task_struct *child, int ctxn,
12222 int *inherited_all)
12225 struct perf_event_context *child_ctx;
12227 if (!event->attr.inherit) {
12228 *inherited_all = 0;
12232 child_ctx = child->perf_event_ctxp[ctxn];
12235 * This is executed from the parent task context, so
12236 * inherit events that have been marked for cloning.
12237 * First allocate and initialize a context for the
12240 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
12244 child->perf_event_ctxp[ctxn] = child_ctx;
12247 ret = inherit_group(event, parent, parent_ctx,
12251 *inherited_all = 0;
12257 * Initialize the perf_event context in task_struct
12259 static int perf_event_init_context(struct task_struct *child, int ctxn)
12261 struct perf_event_context *child_ctx, *parent_ctx;
12262 struct perf_event_context *cloned_ctx;
12263 struct perf_event *event;
12264 struct task_struct *parent = current;
12265 int inherited_all = 1;
12266 unsigned long flags;
12269 if (likely(!parent->perf_event_ctxp[ctxn]))
12273 * If the parent's context is a clone, pin it so it won't get
12274 * swapped under us.
12276 parent_ctx = perf_pin_task_context(parent, ctxn);
12281 * No need to check if parent_ctx != NULL here; since we saw
12282 * it non-NULL earlier, the only reason for it to become NULL
12283 * is if we exit, and since we're currently in the middle of
12284 * a fork we can't be exiting at the same time.
12288 * Lock the parent list. No need to lock the child - not PID
12289 * hashed yet and not running, so nobody can access it.
12291 mutex_lock(&parent_ctx->mutex);
12294 * We dont have to disable NMIs - we are only looking at
12295 * the list, not manipulating it:
12297 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12298 ret = inherit_task_group(event, parent, parent_ctx,
12299 child, ctxn, &inherited_all);
12305 * We can't hold ctx->lock when iterating the ->flexible_group list due
12306 * to allocations, but we need to prevent rotation because
12307 * rotate_ctx() will change the list from interrupt context.
12309 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12310 parent_ctx->rotate_disable = 1;
12311 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12313 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12314 ret = inherit_task_group(event, parent, parent_ctx,
12315 child, ctxn, &inherited_all);
12320 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12321 parent_ctx->rotate_disable = 0;
12323 child_ctx = child->perf_event_ctxp[ctxn];
12325 if (child_ctx && inherited_all) {
12327 * Mark the child context as a clone of the parent
12328 * context, or of whatever the parent is a clone of.
12330 * Note that if the parent is a clone, the holding of
12331 * parent_ctx->lock avoids it from being uncloned.
12333 cloned_ctx = parent_ctx->parent_ctx;
12335 child_ctx->parent_ctx = cloned_ctx;
12336 child_ctx->parent_gen = parent_ctx->parent_gen;
12338 child_ctx->parent_ctx = parent_ctx;
12339 child_ctx->parent_gen = parent_ctx->generation;
12341 get_ctx(child_ctx->parent_ctx);
12344 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12346 mutex_unlock(&parent_ctx->mutex);
12348 perf_unpin_context(parent_ctx);
12349 put_ctx(parent_ctx);
12355 * Initialize the perf_event context in task_struct
12357 int perf_event_init_task(struct task_struct *child)
12361 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12362 mutex_init(&child->perf_event_mutex);
12363 INIT_LIST_HEAD(&child->perf_event_list);
12365 for_each_task_context_nr(ctxn) {
12366 ret = perf_event_init_context(child, ctxn);
12368 perf_event_free_task(child);
12376 static void __init perf_event_init_all_cpus(void)
12378 struct swevent_htable *swhash;
12381 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12383 for_each_possible_cpu(cpu) {
12384 swhash = &per_cpu(swevent_htable, cpu);
12385 mutex_init(&swhash->hlist_mutex);
12386 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12388 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12389 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12391 #ifdef CONFIG_CGROUP_PERF
12392 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12394 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12398 static void perf_swevent_init_cpu(unsigned int cpu)
12400 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12402 mutex_lock(&swhash->hlist_mutex);
12403 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12404 struct swevent_hlist *hlist;
12406 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12408 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12410 mutex_unlock(&swhash->hlist_mutex);
12413 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12414 static void __perf_event_exit_context(void *__info)
12416 struct perf_event_context *ctx = __info;
12417 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12418 struct perf_event *event;
12420 raw_spin_lock(&ctx->lock);
12421 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12422 list_for_each_entry(event, &ctx->event_list, event_entry)
12423 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12424 raw_spin_unlock(&ctx->lock);
12427 static void perf_event_exit_cpu_context(int cpu)
12429 struct perf_cpu_context *cpuctx;
12430 struct perf_event_context *ctx;
12433 mutex_lock(&pmus_lock);
12434 list_for_each_entry(pmu, &pmus, entry) {
12435 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12436 ctx = &cpuctx->ctx;
12438 mutex_lock(&ctx->mutex);
12439 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12440 cpuctx->online = 0;
12441 mutex_unlock(&ctx->mutex);
12443 cpumask_clear_cpu(cpu, perf_online_mask);
12444 mutex_unlock(&pmus_lock);
12448 static void perf_event_exit_cpu_context(int cpu) { }
12452 int perf_event_init_cpu(unsigned int cpu)
12454 struct perf_cpu_context *cpuctx;
12455 struct perf_event_context *ctx;
12458 perf_swevent_init_cpu(cpu);
12460 mutex_lock(&pmus_lock);
12461 cpumask_set_cpu(cpu, perf_online_mask);
12462 list_for_each_entry(pmu, &pmus, entry) {
12463 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12464 ctx = &cpuctx->ctx;
12466 mutex_lock(&ctx->mutex);
12467 cpuctx->online = 1;
12468 mutex_unlock(&ctx->mutex);
12470 mutex_unlock(&pmus_lock);
12475 int perf_event_exit_cpu(unsigned int cpu)
12477 perf_event_exit_cpu_context(cpu);
12482 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12486 for_each_online_cpu(cpu)
12487 perf_event_exit_cpu(cpu);
12493 * Run the perf reboot notifier at the very last possible moment so that
12494 * the generic watchdog code runs as long as possible.
12496 static struct notifier_block perf_reboot_notifier = {
12497 .notifier_call = perf_reboot,
12498 .priority = INT_MIN,
12501 void __init perf_event_init(void)
12505 idr_init(&pmu_idr);
12507 perf_event_init_all_cpus();
12508 init_srcu_struct(&pmus_srcu);
12509 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12510 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12511 perf_pmu_register(&perf_task_clock, NULL, -1);
12512 perf_tp_register();
12513 perf_event_init_cpu(smp_processor_id());
12514 register_reboot_notifier(&perf_reboot_notifier);
12516 ret = init_hw_breakpoint();
12517 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12520 * Build time assertion that we keep the data_head at the intended
12521 * location. IOW, validation we got the __reserved[] size right.
12523 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12527 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12530 struct perf_pmu_events_attr *pmu_attr =
12531 container_of(attr, struct perf_pmu_events_attr, attr);
12533 if (pmu_attr->event_str)
12534 return sprintf(page, "%s\n", pmu_attr->event_str);
12538 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12540 static int __init perf_event_sysfs_init(void)
12545 mutex_lock(&pmus_lock);
12547 ret = bus_register(&pmu_bus);
12551 list_for_each_entry(pmu, &pmus, entry) {
12552 if (!pmu->name || pmu->type < 0)
12555 ret = pmu_dev_alloc(pmu);
12556 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12558 pmu_bus_running = 1;
12562 mutex_unlock(&pmus_lock);
12566 device_initcall(perf_event_sysfs_init);
12568 #ifdef CONFIG_CGROUP_PERF
12569 static struct cgroup_subsys_state *
12570 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12572 struct perf_cgroup *jc;
12574 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12576 return ERR_PTR(-ENOMEM);
12578 jc->info = alloc_percpu(struct perf_cgroup_info);
12581 return ERR_PTR(-ENOMEM);
12587 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12589 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12591 free_percpu(jc->info);
12595 static int __perf_cgroup_move(void *info)
12597 struct task_struct *task = info;
12599 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12604 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12606 struct task_struct *task;
12607 struct cgroup_subsys_state *css;
12609 cgroup_taskset_for_each(task, css, tset)
12610 task_function_call(task, __perf_cgroup_move, task);
12613 struct cgroup_subsys perf_event_cgrp_subsys = {
12614 .css_alloc = perf_cgroup_css_alloc,
12615 .css_free = perf_cgroup_css_free,
12616 .attach = perf_cgroup_attach,
12618 * Implicitly enable on dfl hierarchy so that perf events can
12619 * always be filtered by cgroup2 path as long as perf_event
12620 * controller is not mounted on a legacy hierarchy.
12622 .implicit_on_dfl = true,
12625 #endif /* CONFIG_CGROUP_PERF */