1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/cgroup.h>
37 #include <linux/perf_event.h>
38 #include <linux/trace_events.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/module.h>
42 #include <linux/mman.h>
43 #include <linux/compat.h>
44 #include <linux/bpf.h>
45 #include <linux/filter.h>
46 #include <linux/namei.h>
47 #include <linux/parser.h>
48 #include <linux/sched/clock.h>
49 #include <linux/sched/mm.h>
50 #include <linux/proc_ns.h>
51 #include <linux/mount.h>
55 #include <asm/irq_regs.h>
57 typedef int (*remote_function_f)(void *);
59 struct remote_function_call {
60 struct task_struct *p;
61 remote_function_f func;
66 static void remote_function(void *data)
68 struct remote_function_call *tfc = data;
69 struct task_struct *p = tfc->p;
73 if (task_cpu(p) != smp_processor_id())
77 * Now that we're on right CPU with IRQs disabled, we can test
78 * if we hit the right task without races.
81 tfc->ret = -ESRCH; /* No such (running) process */
86 tfc->ret = tfc->func(tfc->info);
90 * task_function_call - call a function on the cpu on which a task runs
91 * @p: the task to evaluate
92 * @func: the function to be called
93 * @info: the function call argument
95 * Calls the function @func when the task is currently running. This might
96 * be on the current CPU, which just calls the function directly
98 * returns: @func return value, or
99 * -ESRCH - when the process isn't running
100 * -EAGAIN - when the process moved away
103 task_function_call(struct task_struct *p, remote_function_f func, void *info)
105 struct remote_function_call data = {
114 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
117 } while (ret == -EAGAIN);
123 * cpu_function_call - call a function on the cpu
124 * @func: the function to be called
125 * @info: the function call argument
127 * Calls the function @func on the remote cpu.
129 * returns: @func return value or -ENXIO when the cpu is offline
131 static int cpu_function_call(int cpu, remote_function_f func, void *info)
133 struct remote_function_call data = {
137 .ret = -ENXIO, /* No such CPU */
140 smp_call_function_single(cpu, remote_function, &data, 1);
145 static inline struct perf_cpu_context *
146 __get_cpu_context(struct perf_event_context *ctx)
148 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
151 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
152 struct perf_event_context *ctx)
154 raw_spin_lock(&cpuctx->ctx.lock);
156 raw_spin_lock(&ctx->lock);
159 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
160 struct perf_event_context *ctx)
163 raw_spin_unlock(&ctx->lock);
164 raw_spin_unlock(&cpuctx->ctx.lock);
167 #define TASK_TOMBSTONE ((void *)-1L)
169 static bool is_kernel_event(struct perf_event *event)
171 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
175 * On task ctx scheduling...
177 * When !ctx->nr_events a task context will not be scheduled. This means
178 * we can disable the scheduler hooks (for performance) without leaving
179 * pending task ctx state.
181 * This however results in two special cases:
183 * - removing the last event from a task ctx; this is relatively straight
184 * forward and is done in __perf_remove_from_context.
186 * - adding the first event to a task ctx; this is tricky because we cannot
187 * rely on ctx->is_active and therefore cannot use event_function_call().
188 * See perf_install_in_context().
190 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
193 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
194 struct perf_event_context *, void *);
196 struct event_function_struct {
197 struct perf_event *event;
202 static int event_function(void *info)
204 struct event_function_struct *efs = info;
205 struct perf_event *event = efs->event;
206 struct perf_event_context *ctx = event->ctx;
207 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
208 struct perf_event_context *task_ctx = cpuctx->task_ctx;
211 lockdep_assert_irqs_disabled();
213 perf_ctx_lock(cpuctx, task_ctx);
215 * Since we do the IPI call without holding ctx->lock things can have
216 * changed, double check we hit the task we set out to hit.
219 if (ctx->task != current) {
225 * We only use event_function_call() on established contexts,
226 * and event_function() is only ever called when active (or
227 * rather, we'll have bailed in task_function_call() or the
228 * above ctx->task != current test), therefore we must have
229 * ctx->is_active here.
231 WARN_ON_ONCE(!ctx->is_active);
233 * And since we have ctx->is_active, cpuctx->task_ctx must
236 WARN_ON_ONCE(task_ctx != ctx);
238 WARN_ON_ONCE(&cpuctx->ctx != ctx);
241 efs->func(event, cpuctx, ctx, efs->data);
243 perf_ctx_unlock(cpuctx, task_ctx);
248 static void event_function_call(struct perf_event *event, event_f func, void *data)
250 struct perf_event_context *ctx = event->ctx;
251 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
252 struct event_function_struct efs = {
258 if (!event->parent) {
260 * If this is a !child event, we must hold ctx::mutex to
261 * stabilize the the event->ctx relation. See
262 * perf_event_ctx_lock().
264 lockdep_assert_held(&ctx->mutex);
268 cpu_function_call(event->cpu, event_function, &efs);
272 if (task == TASK_TOMBSTONE)
276 if (!task_function_call(task, event_function, &efs))
279 raw_spin_lock_irq(&ctx->lock);
281 * Reload the task pointer, it might have been changed by
282 * a concurrent perf_event_context_sched_out().
285 if (task == TASK_TOMBSTONE) {
286 raw_spin_unlock_irq(&ctx->lock);
289 if (ctx->is_active) {
290 raw_spin_unlock_irq(&ctx->lock);
293 func(event, NULL, ctx, data);
294 raw_spin_unlock_irq(&ctx->lock);
298 * Similar to event_function_call() + event_function(), but hard assumes IRQs
299 * are already disabled and we're on the right CPU.
301 static void event_function_local(struct perf_event *event, event_f func, void *data)
303 struct perf_event_context *ctx = event->ctx;
304 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
305 struct task_struct *task = READ_ONCE(ctx->task);
306 struct perf_event_context *task_ctx = NULL;
308 lockdep_assert_irqs_disabled();
311 if (task == TASK_TOMBSTONE)
317 perf_ctx_lock(cpuctx, task_ctx);
320 if (task == TASK_TOMBSTONE)
325 * We must be either inactive or active and the right task,
326 * otherwise we're screwed, since we cannot IPI to somewhere
329 if (ctx->is_active) {
330 if (WARN_ON_ONCE(task != current))
333 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
337 WARN_ON_ONCE(&cpuctx->ctx != ctx);
340 func(event, cpuctx, ctx, data);
342 perf_ctx_unlock(cpuctx, task_ctx);
345 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
346 PERF_FLAG_FD_OUTPUT |\
347 PERF_FLAG_PID_CGROUP |\
348 PERF_FLAG_FD_CLOEXEC)
351 * branch priv levels that need permission checks
353 #define PERF_SAMPLE_BRANCH_PERM_PLM \
354 (PERF_SAMPLE_BRANCH_KERNEL |\
355 PERF_SAMPLE_BRANCH_HV)
358 EVENT_FLEXIBLE = 0x1,
361 /* see ctx_resched() for details */
363 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
367 * perf_sched_events : >0 events exist
368 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
371 static void perf_sched_delayed(struct work_struct *work);
372 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
373 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
374 static DEFINE_MUTEX(perf_sched_mutex);
375 static atomic_t perf_sched_count;
377 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
378 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
379 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
381 static atomic_t nr_mmap_events __read_mostly;
382 static atomic_t nr_comm_events __read_mostly;
383 static atomic_t nr_namespaces_events __read_mostly;
384 static atomic_t nr_task_events __read_mostly;
385 static atomic_t nr_freq_events __read_mostly;
386 static atomic_t nr_switch_events __read_mostly;
387 static atomic_t nr_ksymbol_events __read_mostly;
388 static atomic_t nr_bpf_events __read_mostly;
390 static LIST_HEAD(pmus);
391 static DEFINE_MUTEX(pmus_lock);
392 static struct srcu_struct pmus_srcu;
393 static cpumask_var_t perf_online_mask;
396 * perf event paranoia level:
397 * -1 - not paranoid at all
398 * 0 - disallow raw tracepoint access for unpriv
399 * 1 - disallow cpu events for unpriv
400 * 2 - disallow kernel profiling for unpriv
402 int sysctl_perf_event_paranoid __read_mostly = 2;
404 /* Minimum for 512 kiB + 1 user control page */
405 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
408 * max perf event sample rate
410 #define DEFAULT_MAX_SAMPLE_RATE 100000
411 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
412 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
414 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
416 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
417 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
419 static int perf_sample_allowed_ns __read_mostly =
420 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
422 static void update_perf_cpu_limits(void)
424 u64 tmp = perf_sample_period_ns;
426 tmp *= sysctl_perf_cpu_time_max_percent;
427 tmp = div_u64(tmp, 100);
431 WRITE_ONCE(perf_sample_allowed_ns, tmp);
434 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
436 int perf_proc_update_handler(struct ctl_table *table, int write,
437 void __user *buffer, size_t *lenp,
441 int perf_cpu = sysctl_perf_cpu_time_max_percent;
443 * If throttling is disabled don't allow the write:
445 if (write && (perf_cpu == 100 || perf_cpu == 0))
448 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
452 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
453 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
454 update_perf_cpu_limits();
459 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
461 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
462 void __user *buffer, size_t *lenp,
465 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
470 if (sysctl_perf_cpu_time_max_percent == 100 ||
471 sysctl_perf_cpu_time_max_percent == 0) {
473 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
474 WRITE_ONCE(perf_sample_allowed_ns, 0);
476 update_perf_cpu_limits();
483 * perf samples are done in some very critical code paths (NMIs).
484 * If they take too much CPU time, the system can lock up and not
485 * get any real work done. This will drop the sample rate when
486 * we detect that events are taking too long.
488 #define NR_ACCUMULATED_SAMPLES 128
489 static DEFINE_PER_CPU(u64, running_sample_length);
491 static u64 __report_avg;
492 static u64 __report_allowed;
494 static void perf_duration_warn(struct irq_work *w)
496 printk_ratelimited(KERN_INFO
497 "perf: interrupt took too long (%lld > %lld), lowering "
498 "kernel.perf_event_max_sample_rate to %d\n",
499 __report_avg, __report_allowed,
500 sysctl_perf_event_sample_rate);
503 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
505 void perf_sample_event_took(u64 sample_len_ns)
507 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
515 /* Decay the counter by 1 average sample. */
516 running_len = __this_cpu_read(running_sample_length);
517 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
518 running_len += sample_len_ns;
519 __this_cpu_write(running_sample_length, running_len);
522 * Note: this will be biased artifically low until we have
523 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
524 * from having to maintain a count.
526 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
527 if (avg_len <= max_len)
530 __report_avg = avg_len;
531 __report_allowed = max_len;
534 * Compute a throttle threshold 25% below the current duration.
536 avg_len += avg_len / 4;
537 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
543 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
544 WRITE_ONCE(max_samples_per_tick, max);
546 sysctl_perf_event_sample_rate = max * HZ;
547 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
549 if (!irq_work_queue(&perf_duration_work)) {
550 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
551 "kernel.perf_event_max_sample_rate to %d\n",
552 __report_avg, __report_allowed,
553 sysctl_perf_event_sample_rate);
557 static atomic64_t perf_event_id;
559 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
560 enum event_type_t event_type);
562 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
563 enum event_type_t event_type,
564 struct task_struct *task);
566 static void update_context_time(struct perf_event_context *ctx);
567 static u64 perf_event_time(struct perf_event *event);
569 void __weak perf_event_print_debug(void) { }
571 extern __weak const char *perf_pmu_name(void)
576 static inline u64 perf_clock(void)
578 return local_clock();
581 static inline u64 perf_event_clock(struct perf_event *event)
583 return event->clock();
587 * State based event timekeeping...
589 * The basic idea is to use event->state to determine which (if any) time
590 * fields to increment with the current delta. This means we only need to
591 * update timestamps when we change state or when they are explicitly requested
594 * Event groups make things a little more complicated, but not terribly so. The
595 * rules for a group are that if the group leader is OFF the entire group is
596 * OFF, irrespecive of what the group member states are. This results in
597 * __perf_effective_state().
599 * A futher ramification is that when a group leader flips between OFF and
600 * !OFF, we need to update all group member times.
603 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
604 * need to make sure the relevant context time is updated before we try and
605 * update our timestamps.
608 static __always_inline enum perf_event_state
609 __perf_effective_state(struct perf_event *event)
611 struct perf_event *leader = event->group_leader;
613 if (leader->state <= PERF_EVENT_STATE_OFF)
614 return leader->state;
619 static __always_inline void
620 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
622 enum perf_event_state state = __perf_effective_state(event);
623 u64 delta = now - event->tstamp;
625 *enabled = event->total_time_enabled;
626 if (state >= PERF_EVENT_STATE_INACTIVE)
629 *running = event->total_time_running;
630 if (state >= PERF_EVENT_STATE_ACTIVE)
634 static void perf_event_update_time(struct perf_event *event)
636 u64 now = perf_event_time(event);
638 __perf_update_times(event, now, &event->total_time_enabled,
639 &event->total_time_running);
643 static void perf_event_update_sibling_time(struct perf_event *leader)
645 struct perf_event *sibling;
647 for_each_sibling_event(sibling, leader)
648 perf_event_update_time(sibling);
652 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
654 if (event->state == state)
657 perf_event_update_time(event);
659 * If a group leader gets enabled/disabled all its siblings
662 if ((event->state < 0) ^ (state < 0))
663 perf_event_update_sibling_time(event);
665 WRITE_ONCE(event->state, state);
668 #ifdef CONFIG_CGROUP_PERF
671 perf_cgroup_match(struct perf_event *event)
673 struct perf_event_context *ctx = event->ctx;
674 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
676 /* @event doesn't care about cgroup */
680 /* wants specific cgroup scope but @cpuctx isn't associated with any */
685 * Cgroup scoping is recursive. An event enabled for a cgroup is
686 * also enabled for all its descendant cgroups. If @cpuctx's
687 * cgroup is a descendant of @event's (the test covers identity
688 * case), it's a match.
690 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
691 event->cgrp->css.cgroup);
694 static inline void perf_detach_cgroup(struct perf_event *event)
696 css_put(&event->cgrp->css);
700 static inline int is_cgroup_event(struct perf_event *event)
702 return event->cgrp != NULL;
705 static inline u64 perf_cgroup_event_time(struct perf_event *event)
707 struct perf_cgroup_info *t;
709 t = per_cpu_ptr(event->cgrp->info, event->cpu);
713 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
715 struct perf_cgroup_info *info;
720 info = this_cpu_ptr(cgrp->info);
722 info->time += now - info->timestamp;
723 info->timestamp = now;
726 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
728 struct perf_cgroup *cgrp = cpuctx->cgrp;
729 struct cgroup_subsys_state *css;
732 for (css = &cgrp->css; css; css = css->parent) {
733 cgrp = container_of(css, struct perf_cgroup, css);
734 __update_cgrp_time(cgrp);
739 static inline void update_cgrp_time_from_event(struct perf_event *event)
741 struct perf_cgroup *cgrp;
744 * ensure we access cgroup data only when needed and
745 * when we know the cgroup is pinned (css_get)
747 if (!is_cgroup_event(event))
750 cgrp = perf_cgroup_from_task(current, event->ctx);
752 * Do not update time when cgroup is not active
754 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
755 __update_cgrp_time(event->cgrp);
759 perf_cgroup_set_timestamp(struct task_struct *task,
760 struct perf_event_context *ctx)
762 struct perf_cgroup *cgrp;
763 struct perf_cgroup_info *info;
764 struct cgroup_subsys_state *css;
767 * ctx->lock held by caller
768 * ensure we do not access cgroup data
769 * unless we have the cgroup pinned (css_get)
771 if (!task || !ctx->nr_cgroups)
774 cgrp = perf_cgroup_from_task(task, ctx);
776 for (css = &cgrp->css; css; css = css->parent) {
777 cgrp = container_of(css, struct perf_cgroup, css);
778 info = this_cpu_ptr(cgrp->info);
779 info->timestamp = ctx->timestamp;
783 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
785 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
786 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
789 * reschedule events based on the cgroup constraint of task.
791 * mode SWOUT : schedule out everything
792 * mode SWIN : schedule in based on cgroup for next
794 static void perf_cgroup_switch(struct task_struct *task, int mode)
796 struct perf_cpu_context *cpuctx;
797 struct list_head *list;
801 * Disable interrupts and preemption to avoid this CPU's
802 * cgrp_cpuctx_entry to change under us.
804 local_irq_save(flags);
806 list = this_cpu_ptr(&cgrp_cpuctx_list);
807 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
808 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
810 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
811 perf_pmu_disable(cpuctx->ctx.pmu);
813 if (mode & PERF_CGROUP_SWOUT) {
814 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
816 * must not be done before ctxswout due
817 * to event_filter_match() in event_sched_out()
822 if (mode & PERF_CGROUP_SWIN) {
823 WARN_ON_ONCE(cpuctx->cgrp);
825 * set cgrp before ctxsw in to allow
826 * event_filter_match() to not have to pass
828 * we pass the cpuctx->ctx to perf_cgroup_from_task()
829 * because cgorup events are only per-cpu
831 cpuctx->cgrp = perf_cgroup_from_task(task,
833 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
835 perf_pmu_enable(cpuctx->ctx.pmu);
836 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
839 local_irq_restore(flags);
842 static inline void perf_cgroup_sched_out(struct task_struct *task,
843 struct task_struct *next)
845 struct perf_cgroup *cgrp1;
846 struct perf_cgroup *cgrp2 = NULL;
850 * we come here when we know perf_cgroup_events > 0
851 * we do not need to pass the ctx here because we know
852 * we are holding the rcu lock
854 cgrp1 = perf_cgroup_from_task(task, NULL);
855 cgrp2 = perf_cgroup_from_task(next, NULL);
858 * only schedule out current cgroup events if we know
859 * that we are switching to a different cgroup. Otherwise,
860 * do no touch the cgroup events.
863 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
868 static inline void perf_cgroup_sched_in(struct task_struct *prev,
869 struct task_struct *task)
871 struct perf_cgroup *cgrp1;
872 struct perf_cgroup *cgrp2 = NULL;
876 * we come here when we know perf_cgroup_events > 0
877 * we do not need to pass the ctx here because we know
878 * we are holding the rcu lock
880 cgrp1 = perf_cgroup_from_task(task, NULL);
881 cgrp2 = perf_cgroup_from_task(prev, NULL);
884 * only need to schedule in cgroup events if we are changing
885 * cgroup during ctxsw. Cgroup events were not scheduled
886 * out of ctxsw out if that was not the case.
889 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
894 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
895 struct perf_event_attr *attr,
896 struct perf_event *group_leader)
898 struct perf_cgroup *cgrp;
899 struct cgroup_subsys_state *css;
900 struct fd f = fdget(fd);
906 css = css_tryget_online_from_dir(f.file->f_path.dentry,
907 &perf_event_cgrp_subsys);
913 cgrp = container_of(css, struct perf_cgroup, css);
917 * all events in a group must monitor
918 * the same cgroup because a task belongs
919 * to only one perf cgroup at a time
921 if (group_leader && group_leader->cgrp != cgrp) {
922 perf_detach_cgroup(event);
931 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
933 struct perf_cgroup_info *t;
934 t = per_cpu_ptr(event->cgrp->info, event->cpu);
935 event->shadow_ctx_time = now - t->timestamp;
939 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
940 * cleared when last cgroup event is removed.
943 list_update_cgroup_event(struct perf_event *event,
944 struct perf_event_context *ctx, bool add)
946 struct perf_cpu_context *cpuctx;
947 struct list_head *cpuctx_entry;
949 if (!is_cgroup_event(event))
953 * Because cgroup events are always per-cpu events,
954 * this will always be called from the right CPU.
956 cpuctx = __get_cpu_context(ctx);
959 * Since setting cpuctx->cgrp is conditional on the current @cgrp
960 * matching the event's cgroup, we must do this for every new event,
961 * because if the first would mismatch, the second would not try again
962 * and we would leave cpuctx->cgrp unset.
964 if (add && !cpuctx->cgrp) {
965 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
967 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
971 if (add && ctx->nr_cgroups++)
973 else if (!add && --ctx->nr_cgroups)
976 /* no cgroup running */
980 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
982 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
984 list_del(cpuctx_entry);
987 #else /* !CONFIG_CGROUP_PERF */
990 perf_cgroup_match(struct perf_event *event)
995 static inline void perf_detach_cgroup(struct perf_event *event)
998 static inline int is_cgroup_event(struct perf_event *event)
1003 static inline void update_cgrp_time_from_event(struct perf_event *event)
1007 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1011 static inline void perf_cgroup_sched_out(struct task_struct *task,
1012 struct task_struct *next)
1016 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1017 struct task_struct *task)
1021 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1022 struct perf_event_attr *attr,
1023 struct perf_event *group_leader)
1029 perf_cgroup_set_timestamp(struct task_struct *task,
1030 struct perf_event_context *ctx)
1035 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1040 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1044 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1050 list_update_cgroup_event(struct perf_event *event,
1051 struct perf_event_context *ctx, bool add)
1058 * set default to be dependent on timer tick just
1059 * like original code
1061 #define PERF_CPU_HRTIMER (1000 / HZ)
1063 * function must be called with interrupts disabled
1065 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1067 struct perf_cpu_context *cpuctx;
1070 lockdep_assert_irqs_disabled();
1072 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1073 rotations = perf_rotate_context(cpuctx);
1075 raw_spin_lock(&cpuctx->hrtimer_lock);
1077 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1079 cpuctx->hrtimer_active = 0;
1080 raw_spin_unlock(&cpuctx->hrtimer_lock);
1082 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1085 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1087 struct hrtimer *timer = &cpuctx->hrtimer;
1088 struct pmu *pmu = cpuctx->ctx.pmu;
1091 /* no multiplexing needed for SW PMU */
1092 if (pmu->task_ctx_nr == perf_sw_context)
1096 * check default is sane, if not set then force to
1097 * default interval (1/tick)
1099 interval = pmu->hrtimer_interval_ms;
1101 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1103 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1105 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1106 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1107 timer->function = perf_mux_hrtimer_handler;
1110 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1112 struct hrtimer *timer = &cpuctx->hrtimer;
1113 struct pmu *pmu = cpuctx->ctx.pmu;
1114 unsigned long flags;
1116 /* not for SW PMU */
1117 if (pmu->task_ctx_nr == perf_sw_context)
1120 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1121 if (!cpuctx->hrtimer_active) {
1122 cpuctx->hrtimer_active = 1;
1123 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1124 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1126 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1131 void perf_pmu_disable(struct pmu *pmu)
1133 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1135 pmu->pmu_disable(pmu);
1138 void perf_pmu_enable(struct pmu *pmu)
1140 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1142 pmu->pmu_enable(pmu);
1145 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1148 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1149 * perf_event_task_tick() are fully serialized because they're strictly cpu
1150 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1151 * disabled, while perf_event_task_tick is called from IRQ context.
1153 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1155 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1157 lockdep_assert_irqs_disabled();
1159 WARN_ON(!list_empty(&ctx->active_ctx_list));
1161 list_add(&ctx->active_ctx_list, head);
1164 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1166 lockdep_assert_irqs_disabled();
1168 WARN_ON(list_empty(&ctx->active_ctx_list));
1170 list_del_init(&ctx->active_ctx_list);
1173 static void get_ctx(struct perf_event_context *ctx)
1175 refcount_inc(&ctx->refcount);
1178 static void free_ctx(struct rcu_head *head)
1180 struct perf_event_context *ctx;
1182 ctx = container_of(head, struct perf_event_context, rcu_head);
1183 kfree(ctx->task_ctx_data);
1187 static void put_ctx(struct perf_event_context *ctx)
1189 if (refcount_dec_and_test(&ctx->refcount)) {
1190 if (ctx->parent_ctx)
1191 put_ctx(ctx->parent_ctx);
1192 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1193 put_task_struct(ctx->task);
1194 call_rcu(&ctx->rcu_head, free_ctx);
1199 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1200 * perf_pmu_migrate_context() we need some magic.
1202 * Those places that change perf_event::ctx will hold both
1203 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1205 * Lock ordering is by mutex address. There are two other sites where
1206 * perf_event_context::mutex nests and those are:
1208 * - perf_event_exit_task_context() [ child , 0 ]
1209 * perf_event_exit_event()
1210 * put_event() [ parent, 1 ]
1212 * - perf_event_init_context() [ parent, 0 ]
1213 * inherit_task_group()
1216 * perf_event_alloc()
1218 * perf_try_init_event() [ child , 1 ]
1220 * While it appears there is an obvious deadlock here -- the parent and child
1221 * nesting levels are inverted between the two. This is in fact safe because
1222 * life-time rules separate them. That is an exiting task cannot fork, and a
1223 * spawning task cannot (yet) exit.
1225 * But remember that that these are parent<->child context relations, and
1226 * migration does not affect children, therefore these two orderings should not
1229 * The change in perf_event::ctx does not affect children (as claimed above)
1230 * because the sys_perf_event_open() case will install a new event and break
1231 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1232 * concerned with cpuctx and that doesn't have children.
1234 * The places that change perf_event::ctx will issue:
1236 * perf_remove_from_context();
1237 * synchronize_rcu();
1238 * perf_install_in_context();
1240 * to affect the change. The remove_from_context() + synchronize_rcu() should
1241 * quiesce the event, after which we can install it in the new location. This
1242 * means that only external vectors (perf_fops, prctl) can perturb the event
1243 * while in transit. Therefore all such accessors should also acquire
1244 * perf_event_context::mutex to serialize against this.
1246 * However; because event->ctx can change while we're waiting to acquire
1247 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1252 * task_struct::perf_event_mutex
1253 * perf_event_context::mutex
1254 * perf_event::child_mutex;
1255 * perf_event_context::lock
1256 * perf_event::mmap_mutex
1261 * cpuctx->mutex / perf_event_context::mutex
1263 static struct perf_event_context *
1264 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1266 struct perf_event_context *ctx;
1270 ctx = READ_ONCE(event->ctx);
1271 if (!refcount_inc_not_zero(&ctx->refcount)) {
1277 mutex_lock_nested(&ctx->mutex, nesting);
1278 if (event->ctx != ctx) {
1279 mutex_unlock(&ctx->mutex);
1287 static inline struct perf_event_context *
1288 perf_event_ctx_lock(struct perf_event *event)
1290 return perf_event_ctx_lock_nested(event, 0);
1293 static void perf_event_ctx_unlock(struct perf_event *event,
1294 struct perf_event_context *ctx)
1296 mutex_unlock(&ctx->mutex);
1301 * This must be done under the ctx->lock, such as to serialize against
1302 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1303 * calling scheduler related locks and ctx->lock nests inside those.
1305 static __must_check struct perf_event_context *
1306 unclone_ctx(struct perf_event_context *ctx)
1308 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1310 lockdep_assert_held(&ctx->lock);
1313 ctx->parent_ctx = NULL;
1319 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1324 * only top level events have the pid namespace they were created in
1327 event = event->parent;
1329 nr = __task_pid_nr_ns(p, type, event->ns);
1330 /* avoid -1 if it is idle thread or runs in another ns */
1331 if (!nr && !pid_alive(p))
1336 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1338 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1341 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1343 return perf_event_pid_type(event, p, PIDTYPE_PID);
1347 * If we inherit events we want to return the parent event id
1350 static u64 primary_event_id(struct perf_event *event)
1355 id = event->parent->id;
1361 * Get the perf_event_context for a task and lock it.
1363 * This has to cope with with the fact that until it is locked,
1364 * the context could get moved to another task.
1366 static struct perf_event_context *
1367 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1369 struct perf_event_context *ctx;
1373 * One of the few rules of preemptible RCU is that one cannot do
1374 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1375 * part of the read side critical section was irqs-enabled -- see
1376 * rcu_read_unlock_special().
1378 * Since ctx->lock nests under rq->lock we must ensure the entire read
1379 * side critical section has interrupts disabled.
1381 local_irq_save(*flags);
1383 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1386 * If this context is a clone of another, it might
1387 * get swapped for another underneath us by
1388 * perf_event_task_sched_out, though the
1389 * rcu_read_lock() protects us from any context
1390 * getting freed. Lock the context and check if it
1391 * got swapped before we could get the lock, and retry
1392 * if so. If we locked the right context, then it
1393 * can't get swapped on us any more.
1395 raw_spin_lock(&ctx->lock);
1396 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1397 raw_spin_unlock(&ctx->lock);
1399 local_irq_restore(*flags);
1403 if (ctx->task == TASK_TOMBSTONE ||
1404 !refcount_inc_not_zero(&ctx->refcount)) {
1405 raw_spin_unlock(&ctx->lock);
1408 WARN_ON_ONCE(ctx->task != task);
1413 local_irq_restore(*flags);
1418 * Get the context for a task and increment its pin_count so it
1419 * can't get swapped to another task. This also increments its
1420 * reference count so that the context can't get freed.
1422 static struct perf_event_context *
1423 perf_pin_task_context(struct task_struct *task, int ctxn)
1425 struct perf_event_context *ctx;
1426 unsigned long flags;
1428 ctx = perf_lock_task_context(task, ctxn, &flags);
1431 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1436 static void perf_unpin_context(struct perf_event_context *ctx)
1438 unsigned long flags;
1440 raw_spin_lock_irqsave(&ctx->lock, flags);
1442 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1446 * Update the record of the current time in a context.
1448 static void update_context_time(struct perf_event_context *ctx)
1450 u64 now = perf_clock();
1452 ctx->time += now - ctx->timestamp;
1453 ctx->timestamp = now;
1456 static u64 perf_event_time(struct perf_event *event)
1458 struct perf_event_context *ctx = event->ctx;
1460 if (is_cgroup_event(event))
1461 return perf_cgroup_event_time(event);
1463 return ctx ? ctx->time : 0;
1466 static enum event_type_t get_event_type(struct perf_event *event)
1468 struct perf_event_context *ctx = event->ctx;
1469 enum event_type_t event_type;
1471 lockdep_assert_held(&ctx->lock);
1474 * It's 'group type', really, because if our group leader is
1475 * pinned, so are we.
1477 if (event->group_leader != event)
1478 event = event->group_leader;
1480 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1482 event_type |= EVENT_CPU;
1488 * Helper function to initialize event group nodes.
1490 static void init_event_group(struct perf_event *event)
1492 RB_CLEAR_NODE(&event->group_node);
1493 event->group_index = 0;
1497 * Extract pinned or flexible groups from the context
1498 * based on event attrs bits.
1500 static struct perf_event_groups *
1501 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1503 if (event->attr.pinned)
1504 return &ctx->pinned_groups;
1506 return &ctx->flexible_groups;
1510 * Helper function to initializes perf_event_group trees.
1512 static void perf_event_groups_init(struct perf_event_groups *groups)
1514 groups->tree = RB_ROOT;
1519 * Compare function for event groups;
1521 * Implements complex key that first sorts by CPU and then by virtual index
1522 * which provides ordering when rotating groups for the same CPU.
1525 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1527 if (left->cpu < right->cpu)
1529 if (left->cpu > right->cpu)
1532 if (left->group_index < right->group_index)
1534 if (left->group_index > right->group_index)
1541 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1542 * key (see perf_event_groups_less). This places it last inside the CPU
1546 perf_event_groups_insert(struct perf_event_groups *groups,
1547 struct perf_event *event)
1549 struct perf_event *node_event;
1550 struct rb_node *parent;
1551 struct rb_node **node;
1553 event->group_index = ++groups->index;
1555 node = &groups->tree.rb_node;
1560 node_event = container_of(*node, struct perf_event, group_node);
1562 if (perf_event_groups_less(event, node_event))
1563 node = &parent->rb_left;
1565 node = &parent->rb_right;
1568 rb_link_node(&event->group_node, parent, node);
1569 rb_insert_color(&event->group_node, &groups->tree);
1573 * Helper function to insert event into the pinned or flexible groups.
1576 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1578 struct perf_event_groups *groups;
1580 groups = get_event_groups(event, ctx);
1581 perf_event_groups_insert(groups, event);
1585 * Delete a group from a tree.
1588 perf_event_groups_delete(struct perf_event_groups *groups,
1589 struct perf_event *event)
1591 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1592 RB_EMPTY_ROOT(&groups->tree));
1594 rb_erase(&event->group_node, &groups->tree);
1595 init_event_group(event);
1599 * Helper function to delete event from its groups.
1602 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1604 struct perf_event_groups *groups;
1606 groups = get_event_groups(event, ctx);
1607 perf_event_groups_delete(groups, event);
1611 * Get the leftmost event in the @cpu subtree.
1613 static struct perf_event *
1614 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1616 struct perf_event *node_event = NULL, *match = NULL;
1617 struct rb_node *node = groups->tree.rb_node;
1620 node_event = container_of(node, struct perf_event, group_node);
1622 if (cpu < node_event->cpu) {
1623 node = node->rb_left;
1624 } else if (cpu > node_event->cpu) {
1625 node = node->rb_right;
1628 node = node->rb_left;
1636 * Like rb_entry_next_safe() for the @cpu subtree.
1638 static struct perf_event *
1639 perf_event_groups_next(struct perf_event *event)
1641 struct perf_event *next;
1643 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1644 if (next && next->cpu == event->cpu)
1651 * Iterate through the whole groups tree.
1653 #define perf_event_groups_for_each(event, groups) \
1654 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1655 typeof(*event), group_node); event; \
1656 event = rb_entry_safe(rb_next(&event->group_node), \
1657 typeof(*event), group_node))
1660 * Add an event from the lists for its context.
1661 * Must be called with ctx->mutex and ctx->lock held.
1664 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1666 lockdep_assert_held(&ctx->lock);
1668 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1669 event->attach_state |= PERF_ATTACH_CONTEXT;
1671 event->tstamp = perf_event_time(event);
1674 * If we're a stand alone event or group leader, we go to the context
1675 * list, group events are kept attached to the group so that
1676 * perf_group_detach can, at all times, locate all siblings.
1678 if (event->group_leader == event) {
1679 event->group_caps = event->event_caps;
1680 add_event_to_groups(event, ctx);
1683 list_update_cgroup_event(event, ctx, true);
1685 list_add_rcu(&event->event_entry, &ctx->event_list);
1687 if (event->attr.inherit_stat)
1694 * Initialize event state based on the perf_event_attr::disabled.
1696 static inline void perf_event__state_init(struct perf_event *event)
1698 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1699 PERF_EVENT_STATE_INACTIVE;
1702 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1704 int entry = sizeof(u64); /* value */
1708 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1709 size += sizeof(u64);
1711 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1712 size += sizeof(u64);
1714 if (event->attr.read_format & PERF_FORMAT_ID)
1715 entry += sizeof(u64);
1717 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1719 size += sizeof(u64);
1723 event->read_size = size;
1726 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1728 struct perf_sample_data *data;
1731 if (sample_type & PERF_SAMPLE_IP)
1732 size += sizeof(data->ip);
1734 if (sample_type & PERF_SAMPLE_ADDR)
1735 size += sizeof(data->addr);
1737 if (sample_type & PERF_SAMPLE_PERIOD)
1738 size += sizeof(data->period);
1740 if (sample_type & PERF_SAMPLE_WEIGHT)
1741 size += sizeof(data->weight);
1743 if (sample_type & PERF_SAMPLE_READ)
1744 size += event->read_size;
1746 if (sample_type & PERF_SAMPLE_DATA_SRC)
1747 size += sizeof(data->data_src.val);
1749 if (sample_type & PERF_SAMPLE_TRANSACTION)
1750 size += sizeof(data->txn);
1752 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1753 size += sizeof(data->phys_addr);
1755 event->header_size = size;
1759 * Called at perf_event creation and when events are attached/detached from a
1762 static void perf_event__header_size(struct perf_event *event)
1764 __perf_event_read_size(event,
1765 event->group_leader->nr_siblings);
1766 __perf_event_header_size(event, event->attr.sample_type);
1769 static void perf_event__id_header_size(struct perf_event *event)
1771 struct perf_sample_data *data;
1772 u64 sample_type = event->attr.sample_type;
1775 if (sample_type & PERF_SAMPLE_TID)
1776 size += sizeof(data->tid_entry);
1778 if (sample_type & PERF_SAMPLE_TIME)
1779 size += sizeof(data->time);
1781 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1782 size += sizeof(data->id);
1784 if (sample_type & PERF_SAMPLE_ID)
1785 size += sizeof(data->id);
1787 if (sample_type & PERF_SAMPLE_STREAM_ID)
1788 size += sizeof(data->stream_id);
1790 if (sample_type & PERF_SAMPLE_CPU)
1791 size += sizeof(data->cpu_entry);
1793 event->id_header_size = size;
1796 static bool perf_event_validate_size(struct perf_event *event)
1799 * The values computed here will be over-written when we actually
1802 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1803 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1804 perf_event__id_header_size(event);
1807 * Sum the lot; should not exceed the 64k limit we have on records.
1808 * Conservative limit to allow for callchains and other variable fields.
1810 if (event->read_size + event->header_size +
1811 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1817 static void perf_group_attach(struct perf_event *event)
1819 struct perf_event *group_leader = event->group_leader, *pos;
1821 lockdep_assert_held(&event->ctx->lock);
1824 * We can have double attach due to group movement in perf_event_open.
1826 if (event->attach_state & PERF_ATTACH_GROUP)
1829 event->attach_state |= PERF_ATTACH_GROUP;
1831 if (group_leader == event)
1834 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1836 group_leader->group_caps &= event->event_caps;
1838 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1839 group_leader->nr_siblings++;
1841 perf_event__header_size(group_leader);
1843 for_each_sibling_event(pos, group_leader)
1844 perf_event__header_size(pos);
1848 * Remove an event from the lists for its context.
1849 * Must be called with ctx->mutex and ctx->lock held.
1852 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1854 WARN_ON_ONCE(event->ctx != ctx);
1855 lockdep_assert_held(&ctx->lock);
1858 * We can have double detach due to exit/hot-unplug + close.
1860 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1863 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1865 list_update_cgroup_event(event, ctx, false);
1868 if (event->attr.inherit_stat)
1871 list_del_rcu(&event->event_entry);
1873 if (event->group_leader == event)
1874 del_event_from_groups(event, ctx);
1877 * If event was in error state, then keep it
1878 * that way, otherwise bogus counts will be
1879 * returned on read(). The only way to get out
1880 * of error state is by explicit re-enabling
1883 if (event->state > PERF_EVENT_STATE_OFF)
1884 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1889 static void perf_group_detach(struct perf_event *event)
1891 struct perf_event *sibling, *tmp;
1892 struct perf_event_context *ctx = event->ctx;
1894 lockdep_assert_held(&ctx->lock);
1897 * We can have double detach due to exit/hot-unplug + close.
1899 if (!(event->attach_state & PERF_ATTACH_GROUP))
1902 event->attach_state &= ~PERF_ATTACH_GROUP;
1905 * If this is a sibling, remove it from its group.
1907 if (event->group_leader != event) {
1908 list_del_init(&event->sibling_list);
1909 event->group_leader->nr_siblings--;
1914 * If this was a group event with sibling events then
1915 * upgrade the siblings to singleton events by adding them
1916 * to whatever list we are on.
1918 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1920 sibling->group_leader = sibling;
1921 list_del_init(&sibling->sibling_list);
1923 /* Inherit group flags from the previous leader */
1924 sibling->group_caps = event->group_caps;
1926 if (!RB_EMPTY_NODE(&event->group_node)) {
1927 add_event_to_groups(sibling, event->ctx);
1929 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1930 struct list_head *list = sibling->attr.pinned ?
1931 &ctx->pinned_active : &ctx->flexible_active;
1933 list_add_tail(&sibling->active_list, list);
1937 WARN_ON_ONCE(sibling->ctx != event->ctx);
1941 perf_event__header_size(event->group_leader);
1943 for_each_sibling_event(tmp, event->group_leader)
1944 perf_event__header_size(tmp);
1947 static bool is_orphaned_event(struct perf_event *event)
1949 return event->state == PERF_EVENT_STATE_DEAD;
1952 static inline int __pmu_filter_match(struct perf_event *event)
1954 struct pmu *pmu = event->pmu;
1955 return pmu->filter_match ? pmu->filter_match(event) : 1;
1959 * Check whether we should attempt to schedule an event group based on
1960 * PMU-specific filtering. An event group can consist of HW and SW events,
1961 * potentially with a SW leader, so we must check all the filters, to
1962 * determine whether a group is schedulable:
1964 static inline int pmu_filter_match(struct perf_event *event)
1966 struct perf_event *sibling;
1968 if (!__pmu_filter_match(event))
1971 for_each_sibling_event(sibling, event) {
1972 if (!__pmu_filter_match(sibling))
1980 event_filter_match(struct perf_event *event)
1982 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1983 perf_cgroup_match(event) && pmu_filter_match(event);
1987 event_sched_out(struct perf_event *event,
1988 struct perf_cpu_context *cpuctx,
1989 struct perf_event_context *ctx)
1991 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1993 WARN_ON_ONCE(event->ctx != ctx);
1994 lockdep_assert_held(&ctx->lock);
1996 if (event->state != PERF_EVENT_STATE_ACTIVE)
2000 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2001 * we can schedule events _OUT_ individually through things like
2002 * __perf_remove_from_context().
2004 list_del_init(&event->active_list);
2006 perf_pmu_disable(event->pmu);
2008 event->pmu->del(event, 0);
2011 if (event->pending_disable) {
2012 event->pending_disable = 0;
2013 state = PERF_EVENT_STATE_OFF;
2015 perf_event_set_state(event, state);
2017 if (!is_software_event(event))
2018 cpuctx->active_oncpu--;
2019 if (!--ctx->nr_active)
2020 perf_event_ctx_deactivate(ctx);
2021 if (event->attr.freq && event->attr.sample_freq)
2023 if (event->attr.exclusive || !cpuctx->active_oncpu)
2024 cpuctx->exclusive = 0;
2026 perf_pmu_enable(event->pmu);
2030 group_sched_out(struct perf_event *group_event,
2031 struct perf_cpu_context *cpuctx,
2032 struct perf_event_context *ctx)
2034 struct perf_event *event;
2036 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2039 perf_pmu_disable(ctx->pmu);
2041 event_sched_out(group_event, cpuctx, ctx);
2044 * Schedule out siblings (if any):
2046 for_each_sibling_event(event, group_event)
2047 event_sched_out(event, cpuctx, ctx);
2049 perf_pmu_enable(ctx->pmu);
2051 if (group_event->attr.exclusive)
2052 cpuctx->exclusive = 0;
2055 #define DETACH_GROUP 0x01UL
2058 * Cross CPU call to remove a performance event
2060 * We disable the event on the hardware level first. After that we
2061 * remove it from the context list.
2064 __perf_remove_from_context(struct perf_event *event,
2065 struct perf_cpu_context *cpuctx,
2066 struct perf_event_context *ctx,
2069 unsigned long flags = (unsigned long)info;
2071 if (ctx->is_active & EVENT_TIME) {
2072 update_context_time(ctx);
2073 update_cgrp_time_from_cpuctx(cpuctx);
2076 event_sched_out(event, cpuctx, ctx);
2077 if (flags & DETACH_GROUP)
2078 perf_group_detach(event);
2079 list_del_event(event, ctx);
2081 if (!ctx->nr_events && ctx->is_active) {
2084 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2085 cpuctx->task_ctx = NULL;
2091 * Remove the event from a task's (or a CPU's) list of events.
2093 * If event->ctx is a cloned context, callers must make sure that
2094 * every task struct that event->ctx->task could possibly point to
2095 * remains valid. This is OK when called from perf_release since
2096 * that only calls us on the top-level context, which can't be a clone.
2097 * When called from perf_event_exit_task, it's OK because the
2098 * context has been detached from its task.
2100 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2102 struct perf_event_context *ctx = event->ctx;
2104 lockdep_assert_held(&ctx->mutex);
2106 event_function_call(event, __perf_remove_from_context, (void *)flags);
2109 * The above event_function_call() can NO-OP when it hits
2110 * TASK_TOMBSTONE. In that case we must already have been detached
2111 * from the context (by perf_event_exit_event()) but the grouping
2112 * might still be in-tact.
2114 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2115 if ((flags & DETACH_GROUP) &&
2116 (event->attach_state & PERF_ATTACH_GROUP)) {
2118 * Since in that case we cannot possibly be scheduled, simply
2121 raw_spin_lock_irq(&ctx->lock);
2122 perf_group_detach(event);
2123 raw_spin_unlock_irq(&ctx->lock);
2128 * Cross CPU call to disable a performance event
2130 static void __perf_event_disable(struct perf_event *event,
2131 struct perf_cpu_context *cpuctx,
2132 struct perf_event_context *ctx,
2135 if (event->state < PERF_EVENT_STATE_INACTIVE)
2138 if (ctx->is_active & EVENT_TIME) {
2139 update_context_time(ctx);
2140 update_cgrp_time_from_event(event);
2143 if (event == event->group_leader)
2144 group_sched_out(event, cpuctx, ctx);
2146 event_sched_out(event, cpuctx, ctx);
2148 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2154 * If event->ctx is a cloned context, callers must make sure that
2155 * every task struct that event->ctx->task could possibly point to
2156 * remains valid. This condition is satisifed when called through
2157 * perf_event_for_each_child or perf_event_for_each because they
2158 * hold the top-level event's child_mutex, so any descendant that
2159 * goes to exit will block in perf_event_exit_event().
2161 * When called from perf_pending_event it's OK because event->ctx
2162 * is the current context on this CPU and preemption is disabled,
2163 * hence we can't get into perf_event_task_sched_out for this context.
2165 static void _perf_event_disable(struct perf_event *event)
2167 struct perf_event_context *ctx = event->ctx;
2169 raw_spin_lock_irq(&ctx->lock);
2170 if (event->state <= PERF_EVENT_STATE_OFF) {
2171 raw_spin_unlock_irq(&ctx->lock);
2174 raw_spin_unlock_irq(&ctx->lock);
2176 event_function_call(event, __perf_event_disable, NULL);
2179 void perf_event_disable_local(struct perf_event *event)
2181 event_function_local(event, __perf_event_disable, NULL);
2185 * Strictly speaking kernel users cannot create groups and therefore this
2186 * interface does not need the perf_event_ctx_lock() magic.
2188 void perf_event_disable(struct perf_event *event)
2190 struct perf_event_context *ctx;
2192 ctx = perf_event_ctx_lock(event);
2193 _perf_event_disable(event);
2194 perf_event_ctx_unlock(event, ctx);
2196 EXPORT_SYMBOL_GPL(perf_event_disable);
2198 void perf_event_disable_inatomic(struct perf_event *event)
2200 event->pending_disable = 1;
2201 irq_work_queue(&event->pending);
2204 static void perf_set_shadow_time(struct perf_event *event,
2205 struct perf_event_context *ctx)
2208 * use the correct time source for the time snapshot
2210 * We could get by without this by leveraging the
2211 * fact that to get to this function, the caller
2212 * has most likely already called update_context_time()
2213 * and update_cgrp_time_xx() and thus both timestamp
2214 * are identical (or very close). Given that tstamp is,
2215 * already adjusted for cgroup, we could say that:
2216 * tstamp - ctx->timestamp
2218 * tstamp - cgrp->timestamp.
2220 * Then, in perf_output_read(), the calculation would
2221 * work with no changes because:
2222 * - event is guaranteed scheduled in
2223 * - no scheduled out in between
2224 * - thus the timestamp would be the same
2226 * But this is a bit hairy.
2228 * So instead, we have an explicit cgroup call to remain
2229 * within the time time source all along. We believe it
2230 * is cleaner and simpler to understand.
2232 if (is_cgroup_event(event))
2233 perf_cgroup_set_shadow_time(event, event->tstamp);
2235 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2238 #define MAX_INTERRUPTS (~0ULL)
2240 static void perf_log_throttle(struct perf_event *event, int enable);
2241 static void perf_log_itrace_start(struct perf_event *event);
2244 event_sched_in(struct perf_event *event,
2245 struct perf_cpu_context *cpuctx,
2246 struct perf_event_context *ctx)
2250 lockdep_assert_held(&ctx->lock);
2252 if (event->state <= PERF_EVENT_STATE_OFF)
2255 WRITE_ONCE(event->oncpu, smp_processor_id());
2257 * Order event::oncpu write to happen before the ACTIVE state is
2258 * visible. This allows perf_event_{stop,read}() to observe the correct
2259 * ->oncpu if it sees ACTIVE.
2262 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2265 * Unthrottle events, since we scheduled we might have missed several
2266 * ticks already, also for a heavily scheduling task there is little
2267 * guarantee it'll get a tick in a timely manner.
2269 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2270 perf_log_throttle(event, 1);
2271 event->hw.interrupts = 0;
2274 perf_pmu_disable(event->pmu);
2276 perf_set_shadow_time(event, ctx);
2278 perf_log_itrace_start(event);
2280 if (event->pmu->add(event, PERF_EF_START)) {
2281 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2287 if (!is_software_event(event))
2288 cpuctx->active_oncpu++;
2289 if (!ctx->nr_active++)
2290 perf_event_ctx_activate(ctx);
2291 if (event->attr.freq && event->attr.sample_freq)
2294 if (event->attr.exclusive)
2295 cpuctx->exclusive = 1;
2298 perf_pmu_enable(event->pmu);
2304 group_sched_in(struct perf_event *group_event,
2305 struct perf_cpu_context *cpuctx,
2306 struct perf_event_context *ctx)
2308 struct perf_event *event, *partial_group = NULL;
2309 struct pmu *pmu = ctx->pmu;
2311 if (group_event->state == PERF_EVENT_STATE_OFF)
2314 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2316 if (event_sched_in(group_event, cpuctx, ctx)) {
2317 pmu->cancel_txn(pmu);
2318 perf_mux_hrtimer_restart(cpuctx);
2323 * Schedule in siblings as one group (if any):
2325 for_each_sibling_event(event, group_event) {
2326 if (event_sched_in(event, cpuctx, ctx)) {
2327 partial_group = event;
2332 if (!pmu->commit_txn(pmu))
2337 * Groups can be scheduled in as one unit only, so undo any
2338 * partial group before returning:
2339 * The events up to the failed event are scheduled out normally.
2341 for_each_sibling_event(event, group_event) {
2342 if (event == partial_group)
2345 event_sched_out(event, cpuctx, ctx);
2347 event_sched_out(group_event, cpuctx, ctx);
2349 pmu->cancel_txn(pmu);
2351 perf_mux_hrtimer_restart(cpuctx);
2357 * Work out whether we can put this event group on the CPU now.
2359 static int group_can_go_on(struct perf_event *event,
2360 struct perf_cpu_context *cpuctx,
2364 * Groups consisting entirely of software events can always go on.
2366 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2369 * If an exclusive group is already on, no other hardware
2372 if (cpuctx->exclusive)
2375 * If this group is exclusive and there are already
2376 * events on the CPU, it can't go on.
2378 if (event->attr.exclusive && cpuctx->active_oncpu)
2381 * Otherwise, try to add it if all previous groups were able
2387 static void add_event_to_ctx(struct perf_event *event,
2388 struct perf_event_context *ctx)
2390 list_add_event(event, ctx);
2391 perf_group_attach(event);
2394 static void ctx_sched_out(struct perf_event_context *ctx,
2395 struct perf_cpu_context *cpuctx,
2396 enum event_type_t event_type);
2398 ctx_sched_in(struct perf_event_context *ctx,
2399 struct perf_cpu_context *cpuctx,
2400 enum event_type_t event_type,
2401 struct task_struct *task);
2403 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2404 struct perf_event_context *ctx,
2405 enum event_type_t event_type)
2407 if (!cpuctx->task_ctx)
2410 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2413 ctx_sched_out(ctx, cpuctx, event_type);
2416 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2417 struct perf_event_context *ctx,
2418 struct task_struct *task)
2420 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2422 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2423 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2425 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2429 * We want to maintain the following priority of scheduling:
2430 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2431 * - task pinned (EVENT_PINNED)
2432 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2433 * - task flexible (EVENT_FLEXIBLE).
2435 * In order to avoid unscheduling and scheduling back in everything every
2436 * time an event is added, only do it for the groups of equal priority and
2439 * This can be called after a batch operation on task events, in which case
2440 * event_type is a bit mask of the types of events involved. For CPU events,
2441 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2443 static void ctx_resched(struct perf_cpu_context *cpuctx,
2444 struct perf_event_context *task_ctx,
2445 enum event_type_t event_type)
2447 enum event_type_t ctx_event_type;
2448 bool cpu_event = !!(event_type & EVENT_CPU);
2451 * If pinned groups are involved, flexible groups also need to be
2454 if (event_type & EVENT_PINNED)
2455 event_type |= EVENT_FLEXIBLE;
2457 ctx_event_type = event_type & EVENT_ALL;
2459 perf_pmu_disable(cpuctx->ctx.pmu);
2461 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2464 * Decide which cpu ctx groups to schedule out based on the types
2465 * of events that caused rescheduling:
2466 * - EVENT_CPU: schedule out corresponding groups;
2467 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2468 * - otherwise, do nothing more.
2471 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2472 else if (ctx_event_type & EVENT_PINNED)
2473 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2475 perf_event_sched_in(cpuctx, task_ctx, current);
2476 perf_pmu_enable(cpuctx->ctx.pmu);
2480 * Cross CPU call to install and enable a performance event
2482 * Very similar to remote_function() + event_function() but cannot assume that
2483 * things like ctx->is_active and cpuctx->task_ctx are set.
2485 static int __perf_install_in_context(void *info)
2487 struct perf_event *event = info;
2488 struct perf_event_context *ctx = event->ctx;
2489 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2490 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2491 bool reprogram = true;
2494 raw_spin_lock(&cpuctx->ctx.lock);
2496 raw_spin_lock(&ctx->lock);
2499 reprogram = (ctx->task == current);
2502 * If the task is running, it must be running on this CPU,
2503 * otherwise we cannot reprogram things.
2505 * If its not running, we don't care, ctx->lock will
2506 * serialize against it becoming runnable.
2508 if (task_curr(ctx->task) && !reprogram) {
2513 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2514 } else if (task_ctx) {
2515 raw_spin_lock(&task_ctx->lock);
2518 #ifdef CONFIG_CGROUP_PERF
2519 if (is_cgroup_event(event)) {
2521 * If the current cgroup doesn't match the event's
2522 * cgroup, we should not try to schedule it.
2524 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2525 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2526 event->cgrp->css.cgroup);
2531 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2532 add_event_to_ctx(event, ctx);
2533 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2535 add_event_to_ctx(event, ctx);
2539 perf_ctx_unlock(cpuctx, task_ctx);
2545 * Attach a performance event to a context.
2547 * Very similar to event_function_call, see comment there.
2550 perf_install_in_context(struct perf_event_context *ctx,
2551 struct perf_event *event,
2554 struct task_struct *task = READ_ONCE(ctx->task);
2556 lockdep_assert_held(&ctx->mutex);
2558 if (event->cpu != -1)
2562 * Ensures that if we can observe event->ctx, both the event and ctx
2563 * will be 'complete'. See perf_iterate_sb_cpu().
2565 smp_store_release(&event->ctx, ctx);
2568 cpu_function_call(cpu, __perf_install_in_context, event);
2573 * Should not happen, we validate the ctx is still alive before calling.
2575 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2579 * Installing events is tricky because we cannot rely on ctx->is_active
2580 * to be set in case this is the nr_events 0 -> 1 transition.
2582 * Instead we use task_curr(), which tells us if the task is running.
2583 * However, since we use task_curr() outside of rq::lock, we can race
2584 * against the actual state. This means the result can be wrong.
2586 * If we get a false positive, we retry, this is harmless.
2588 * If we get a false negative, things are complicated. If we are after
2589 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2590 * value must be correct. If we're before, it doesn't matter since
2591 * perf_event_context_sched_in() will program the counter.
2593 * However, this hinges on the remote context switch having observed
2594 * our task->perf_event_ctxp[] store, such that it will in fact take
2595 * ctx::lock in perf_event_context_sched_in().
2597 * We do this by task_function_call(), if the IPI fails to hit the task
2598 * we know any future context switch of task must see the
2599 * perf_event_ctpx[] store.
2603 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2604 * task_cpu() load, such that if the IPI then does not find the task
2605 * running, a future context switch of that task must observe the
2610 if (!task_function_call(task, __perf_install_in_context, event))
2613 raw_spin_lock_irq(&ctx->lock);
2615 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2617 * Cannot happen because we already checked above (which also
2618 * cannot happen), and we hold ctx->mutex, which serializes us
2619 * against perf_event_exit_task_context().
2621 raw_spin_unlock_irq(&ctx->lock);
2625 * If the task is not running, ctx->lock will avoid it becoming so,
2626 * thus we can safely install the event.
2628 if (task_curr(task)) {
2629 raw_spin_unlock_irq(&ctx->lock);
2632 add_event_to_ctx(event, ctx);
2633 raw_spin_unlock_irq(&ctx->lock);
2637 * Cross CPU call to enable a performance event
2639 static void __perf_event_enable(struct perf_event *event,
2640 struct perf_cpu_context *cpuctx,
2641 struct perf_event_context *ctx,
2644 struct perf_event *leader = event->group_leader;
2645 struct perf_event_context *task_ctx;
2647 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2648 event->state <= PERF_EVENT_STATE_ERROR)
2652 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2654 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2656 if (!ctx->is_active)
2659 if (!event_filter_match(event)) {
2660 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2665 * If the event is in a group and isn't the group leader,
2666 * then don't put it on unless the group is on.
2668 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2669 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2673 task_ctx = cpuctx->task_ctx;
2675 WARN_ON_ONCE(task_ctx != ctx);
2677 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2683 * If event->ctx is a cloned context, callers must make sure that
2684 * every task struct that event->ctx->task could possibly point to
2685 * remains valid. This condition is satisfied when called through
2686 * perf_event_for_each_child or perf_event_for_each as described
2687 * for perf_event_disable.
2689 static void _perf_event_enable(struct perf_event *event)
2691 struct perf_event_context *ctx = event->ctx;
2693 raw_spin_lock_irq(&ctx->lock);
2694 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2695 event->state < PERF_EVENT_STATE_ERROR) {
2696 raw_spin_unlock_irq(&ctx->lock);
2701 * If the event is in error state, clear that first.
2703 * That way, if we see the event in error state below, we know that it
2704 * has gone back into error state, as distinct from the task having
2705 * been scheduled away before the cross-call arrived.
2707 if (event->state == PERF_EVENT_STATE_ERROR)
2708 event->state = PERF_EVENT_STATE_OFF;
2709 raw_spin_unlock_irq(&ctx->lock);
2711 event_function_call(event, __perf_event_enable, NULL);
2715 * See perf_event_disable();
2717 void perf_event_enable(struct perf_event *event)
2719 struct perf_event_context *ctx;
2721 ctx = perf_event_ctx_lock(event);
2722 _perf_event_enable(event);
2723 perf_event_ctx_unlock(event, ctx);
2725 EXPORT_SYMBOL_GPL(perf_event_enable);
2727 struct stop_event_data {
2728 struct perf_event *event;
2729 unsigned int restart;
2732 static int __perf_event_stop(void *info)
2734 struct stop_event_data *sd = info;
2735 struct perf_event *event = sd->event;
2737 /* if it's already INACTIVE, do nothing */
2738 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2741 /* matches smp_wmb() in event_sched_in() */
2745 * There is a window with interrupts enabled before we get here,
2746 * so we need to check again lest we try to stop another CPU's event.
2748 if (READ_ONCE(event->oncpu) != smp_processor_id())
2751 event->pmu->stop(event, PERF_EF_UPDATE);
2754 * May race with the actual stop (through perf_pmu_output_stop()),
2755 * but it is only used for events with AUX ring buffer, and such
2756 * events will refuse to restart because of rb::aux_mmap_count==0,
2757 * see comments in perf_aux_output_begin().
2759 * Since this is happening on an event-local CPU, no trace is lost
2763 event->pmu->start(event, 0);
2768 static int perf_event_stop(struct perf_event *event, int restart)
2770 struct stop_event_data sd = {
2777 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2780 /* matches smp_wmb() in event_sched_in() */
2784 * We only want to restart ACTIVE events, so if the event goes
2785 * inactive here (event->oncpu==-1), there's nothing more to do;
2786 * fall through with ret==-ENXIO.
2788 ret = cpu_function_call(READ_ONCE(event->oncpu),
2789 __perf_event_stop, &sd);
2790 } while (ret == -EAGAIN);
2796 * In order to contain the amount of racy and tricky in the address filter
2797 * configuration management, it is a two part process:
2799 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2800 * we update the addresses of corresponding vmas in
2801 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2802 * (p2) when an event is scheduled in (pmu::add), it calls
2803 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2804 * if the generation has changed since the previous call.
2806 * If (p1) happens while the event is active, we restart it to force (p2).
2808 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2809 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2811 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2812 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2814 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2817 void perf_event_addr_filters_sync(struct perf_event *event)
2819 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2821 if (!has_addr_filter(event))
2824 raw_spin_lock(&ifh->lock);
2825 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2826 event->pmu->addr_filters_sync(event);
2827 event->hw.addr_filters_gen = event->addr_filters_gen;
2829 raw_spin_unlock(&ifh->lock);
2831 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2833 static int _perf_event_refresh(struct perf_event *event, int refresh)
2836 * not supported on inherited events
2838 if (event->attr.inherit || !is_sampling_event(event))
2841 atomic_add(refresh, &event->event_limit);
2842 _perf_event_enable(event);
2848 * See perf_event_disable()
2850 int perf_event_refresh(struct perf_event *event, int refresh)
2852 struct perf_event_context *ctx;
2855 ctx = perf_event_ctx_lock(event);
2856 ret = _perf_event_refresh(event, refresh);
2857 perf_event_ctx_unlock(event, ctx);
2861 EXPORT_SYMBOL_GPL(perf_event_refresh);
2863 static int perf_event_modify_breakpoint(struct perf_event *bp,
2864 struct perf_event_attr *attr)
2868 _perf_event_disable(bp);
2870 err = modify_user_hw_breakpoint_check(bp, attr, true);
2872 if (!bp->attr.disabled)
2873 _perf_event_enable(bp);
2878 static int perf_event_modify_attr(struct perf_event *event,
2879 struct perf_event_attr *attr)
2881 if (event->attr.type != attr->type)
2884 switch (event->attr.type) {
2885 case PERF_TYPE_BREAKPOINT:
2886 return perf_event_modify_breakpoint(event, attr);
2888 /* Place holder for future additions. */
2893 static void ctx_sched_out(struct perf_event_context *ctx,
2894 struct perf_cpu_context *cpuctx,
2895 enum event_type_t event_type)
2897 struct perf_event *event, *tmp;
2898 int is_active = ctx->is_active;
2900 lockdep_assert_held(&ctx->lock);
2902 if (likely(!ctx->nr_events)) {
2904 * See __perf_remove_from_context().
2906 WARN_ON_ONCE(ctx->is_active);
2908 WARN_ON_ONCE(cpuctx->task_ctx);
2912 ctx->is_active &= ~event_type;
2913 if (!(ctx->is_active & EVENT_ALL))
2917 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2918 if (!ctx->is_active)
2919 cpuctx->task_ctx = NULL;
2923 * Always update time if it was set; not only when it changes.
2924 * Otherwise we can 'forget' to update time for any but the last
2925 * context we sched out. For example:
2927 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2928 * ctx_sched_out(.event_type = EVENT_PINNED)
2930 * would only update time for the pinned events.
2932 if (is_active & EVENT_TIME) {
2933 /* update (and stop) ctx time */
2934 update_context_time(ctx);
2935 update_cgrp_time_from_cpuctx(cpuctx);
2938 is_active ^= ctx->is_active; /* changed bits */
2940 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2943 perf_pmu_disable(ctx->pmu);
2944 if (is_active & EVENT_PINNED) {
2945 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2946 group_sched_out(event, cpuctx, ctx);
2949 if (is_active & EVENT_FLEXIBLE) {
2950 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2951 group_sched_out(event, cpuctx, ctx);
2953 perf_pmu_enable(ctx->pmu);
2957 * Test whether two contexts are equivalent, i.e. whether they have both been
2958 * cloned from the same version of the same context.
2960 * Equivalence is measured using a generation number in the context that is
2961 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2962 * and list_del_event().
2964 static int context_equiv(struct perf_event_context *ctx1,
2965 struct perf_event_context *ctx2)
2967 lockdep_assert_held(&ctx1->lock);
2968 lockdep_assert_held(&ctx2->lock);
2970 /* Pinning disables the swap optimization */
2971 if (ctx1->pin_count || ctx2->pin_count)
2974 /* If ctx1 is the parent of ctx2 */
2975 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2978 /* If ctx2 is the parent of ctx1 */
2979 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2983 * If ctx1 and ctx2 have the same parent; we flatten the parent
2984 * hierarchy, see perf_event_init_context().
2986 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2987 ctx1->parent_gen == ctx2->parent_gen)
2994 static void __perf_event_sync_stat(struct perf_event *event,
2995 struct perf_event *next_event)
2999 if (!event->attr.inherit_stat)
3003 * Update the event value, we cannot use perf_event_read()
3004 * because we're in the middle of a context switch and have IRQs
3005 * disabled, which upsets smp_call_function_single(), however
3006 * we know the event must be on the current CPU, therefore we
3007 * don't need to use it.
3009 if (event->state == PERF_EVENT_STATE_ACTIVE)
3010 event->pmu->read(event);
3012 perf_event_update_time(event);
3015 * In order to keep per-task stats reliable we need to flip the event
3016 * values when we flip the contexts.
3018 value = local64_read(&next_event->count);
3019 value = local64_xchg(&event->count, value);
3020 local64_set(&next_event->count, value);
3022 swap(event->total_time_enabled, next_event->total_time_enabled);
3023 swap(event->total_time_running, next_event->total_time_running);
3026 * Since we swizzled the values, update the user visible data too.
3028 perf_event_update_userpage(event);
3029 perf_event_update_userpage(next_event);
3032 static void perf_event_sync_stat(struct perf_event_context *ctx,
3033 struct perf_event_context *next_ctx)
3035 struct perf_event *event, *next_event;
3040 update_context_time(ctx);
3042 event = list_first_entry(&ctx->event_list,
3043 struct perf_event, event_entry);
3045 next_event = list_first_entry(&next_ctx->event_list,
3046 struct perf_event, event_entry);
3048 while (&event->event_entry != &ctx->event_list &&
3049 &next_event->event_entry != &next_ctx->event_list) {
3051 __perf_event_sync_stat(event, next_event);
3053 event = list_next_entry(event, event_entry);
3054 next_event = list_next_entry(next_event, event_entry);
3058 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3059 struct task_struct *next)
3061 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3062 struct perf_event_context *next_ctx;
3063 struct perf_event_context *parent, *next_parent;
3064 struct perf_cpu_context *cpuctx;
3070 cpuctx = __get_cpu_context(ctx);
3071 if (!cpuctx->task_ctx)
3075 next_ctx = next->perf_event_ctxp[ctxn];
3079 parent = rcu_dereference(ctx->parent_ctx);
3080 next_parent = rcu_dereference(next_ctx->parent_ctx);
3082 /* If neither context have a parent context; they cannot be clones. */
3083 if (!parent && !next_parent)
3086 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3088 * Looks like the two contexts are clones, so we might be
3089 * able to optimize the context switch. We lock both
3090 * contexts and check that they are clones under the
3091 * lock (including re-checking that neither has been
3092 * uncloned in the meantime). It doesn't matter which
3093 * order we take the locks because no other cpu could
3094 * be trying to lock both of these tasks.
3096 raw_spin_lock(&ctx->lock);
3097 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3098 if (context_equiv(ctx, next_ctx)) {
3099 WRITE_ONCE(ctx->task, next);
3100 WRITE_ONCE(next_ctx->task, task);
3102 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3105 * RCU_INIT_POINTER here is safe because we've not
3106 * modified the ctx and the above modification of
3107 * ctx->task and ctx->task_ctx_data are immaterial
3108 * since those values are always verified under
3109 * ctx->lock which we're now holding.
3111 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3112 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3116 perf_event_sync_stat(ctx, next_ctx);
3118 raw_spin_unlock(&next_ctx->lock);
3119 raw_spin_unlock(&ctx->lock);
3125 raw_spin_lock(&ctx->lock);
3126 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3127 raw_spin_unlock(&ctx->lock);
3131 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3133 void perf_sched_cb_dec(struct pmu *pmu)
3135 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3137 this_cpu_dec(perf_sched_cb_usages);
3139 if (!--cpuctx->sched_cb_usage)
3140 list_del(&cpuctx->sched_cb_entry);
3144 void perf_sched_cb_inc(struct pmu *pmu)
3146 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3148 if (!cpuctx->sched_cb_usage++)
3149 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3151 this_cpu_inc(perf_sched_cb_usages);
3155 * This function provides the context switch callback to the lower code
3156 * layer. It is invoked ONLY when the context switch callback is enabled.
3158 * This callback is relevant even to per-cpu events; for example multi event
3159 * PEBS requires this to provide PID/TID information. This requires we flush
3160 * all queued PEBS records before we context switch to a new task.
3162 static void perf_pmu_sched_task(struct task_struct *prev,
3163 struct task_struct *next,
3166 struct perf_cpu_context *cpuctx;
3172 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3173 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3175 if (WARN_ON_ONCE(!pmu->sched_task))
3178 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3179 perf_pmu_disable(pmu);
3181 pmu->sched_task(cpuctx->task_ctx, sched_in);
3183 perf_pmu_enable(pmu);
3184 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3188 static void perf_event_switch(struct task_struct *task,
3189 struct task_struct *next_prev, bool sched_in);
3191 #define for_each_task_context_nr(ctxn) \
3192 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3195 * Called from scheduler to remove the events of the current task,
3196 * with interrupts disabled.
3198 * We stop each event and update the event value in event->count.
3200 * This does not protect us against NMI, but disable()
3201 * sets the disabled bit in the control field of event _before_
3202 * accessing the event control register. If a NMI hits, then it will
3203 * not restart the event.
3205 void __perf_event_task_sched_out(struct task_struct *task,
3206 struct task_struct *next)
3210 if (__this_cpu_read(perf_sched_cb_usages))
3211 perf_pmu_sched_task(task, next, false);
3213 if (atomic_read(&nr_switch_events))
3214 perf_event_switch(task, next, false);
3216 for_each_task_context_nr(ctxn)
3217 perf_event_context_sched_out(task, ctxn, next);
3220 * if cgroup events exist on this CPU, then we need
3221 * to check if we have to switch out PMU state.
3222 * cgroup event are system-wide mode only
3224 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3225 perf_cgroup_sched_out(task, next);
3229 * Called with IRQs disabled
3231 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3232 enum event_type_t event_type)
3234 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3237 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3238 int (*func)(struct perf_event *, void *), void *data)
3240 struct perf_event **evt, *evt1, *evt2;
3243 evt1 = perf_event_groups_first(groups, -1);
3244 evt2 = perf_event_groups_first(groups, cpu);
3246 while (evt1 || evt2) {
3248 if (evt1->group_index < evt2->group_index)
3258 ret = func(*evt, data);
3262 *evt = perf_event_groups_next(*evt);
3268 struct sched_in_data {
3269 struct perf_event_context *ctx;
3270 struct perf_cpu_context *cpuctx;
3274 static int pinned_sched_in(struct perf_event *event, void *data)
3276 struct sched_in_data *sid = data;
3278 if (event->state <= PERF_EVENT_STATE_OFF)
3281 if (!event_filter_match(event))
3284 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3285 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3286 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3290 * If this pinned group hasn't been scheduled,
3291 * put it in error state.
3293 if (event->state == PERF_EVENT_STATE_INACTIVE)
3294 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3299 static int flexible_sched_in(struct perf_event *event, void *data)
3301 struct sched_in_data *sid = data;
3303 if (event->state <= PERF_EVENT_STATE_OFF)
3306 if (!event_filter_match(event))
3309 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3310 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3311 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3313 sid->can_add_hw = 0;
3320 ctx_pinned_sched_in(struct perf_event_context *ctx,
3321 struct perf_cpu_context *cpuctx)
3323 struct sched_in_data sid = {
3329 visit_groups_merge(&ctx->pinned_groups,
3331 pinned_sched_in, &sid);
3335 ctx_flexible_sched_in(struct perf_event_context *ctx,
3336 struct perf_cpu_context *cpuctx)
3338 struct sched_in_data sid = {
3344 visit_groups_merge(&ctx->flexible_groups,
3346 flexible_sched_in, &sid);
3350 ctx_sched_in(struct perf_event_context *ctx,
3351 struct perf_cpu_context *cpuctx,
3352 enum event_type_t event_type,
3353 struct task_struct *task)
3355 int is_active = ctx->is_active;
3358 lockdep_assert_held(&ctx->lock);
3360 if (likely(!ctx->nr_events))
3363 ctx->is_active |= (event_type | EVENT_TIME);
3366 cpuctx->task_ctx = ctx;
3368 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3371 is_active ^= ctx->is_active; /* changed bits */
3373 if (is_active & EVENT_TIME) {
3374 /* start ctx time */
3376 ctx->timestamp = now;
3377 perf_cgroup_set_timestamp(task, ctx);
3381 * First go through the list and put on any pinned groups
3382 * in order to give them the best chance of going on.
3384 if (is_active & EVENT_PINNED)
3385 ctx_pinned_sched_in(ctx, cpuctx);
3387 /* Then walk through the lower prio flexible groups */
3388 if (is_active & EVENT_FLEXIBLE)
3389 ctx_flexible_sched_in(ctx, cpuctx);
3392 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3393 enum event_type_t event_type,
3394 struct task_struct *task)
3396 struct perf_event_context *ctx = &cpuctx->ctx;
3398 ctx_sched_in(ctx, cpuctx, event_type, task);
3401 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3402 struct task_struct *task)
3404 struct perf_cpu_context *cpuctx;
3406 cpuctx = __get_cpu_context(ctx);
3407 if (cpuctx->task_ctx == ctx)
3410 perf_ctx_lock(cpuctx, ctx);
3412 * We must check ctx->nr_events while holding ctx->lock, such
3413 * that we serialize against perf_install_in_context().
3415 if (!ctx->nr_events)
3418 perf_pmu_disable(ctx->pmu);
3420 * We want to keep the following priority order:
3421 * cpu pinned (that don't need to move), task pinned,
3422 * cpu flexible, task flexible.
3424 * However, if task's ctx is not carrying any pinned
3425 * events, no need to flip the cpuctx's events around.
3427 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3428 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3429 perf_event_sched_in(cpuctx, ctx, task);
3430 perf_pmu_enable(ctx->pmu);
3433 perf_ctx_unlock(cpuctx, ctx);
3437 * Called from scheduler to add the events of the current task
3438 * with interrupts disabled.
3440 * We restore the event value and then enable it.
3442 * This does not protect us against NMI, but enable()
3443 * sets the enabled bit in the control field of event _before_
3444 * accessing the event control register. If a NMI hits, then it will
3445 * keep the event running.
3447 void __perf_event_task_sched_in(struct task_struct *prev,
3448 struct task_struct *task)
3450 struct perf_event_context *ctx;
3454 * If cgroup events exist on this CPU, then we need to check if we have
3455 * to switch in PMU state; cgroup event are system-wide mode only.
3457 * Since cgroup events are CPU events, we must schedule these in before
3458 * we schedule in the task events.
3460 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3461 perf_cgroup_sched_in(prev, task);
3463 for_each_task_context_nr(ctxn) {
3464 ctx = task->perf_event_ctxp[ctxn];
3468 perf_event_context_sched_in(ctx, task);
3471 if (atomic_read(&nr_switch_events))
3472 perf_event_switch(task, prev, true);
3474 if (__this_cpu_read(perf_sched_cb_usages))
3475 perf_pmu_sched_task(prev, task, true);
3478 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3480 u64 frequency = event->attr.sample_freq;
3481 u64 sec = NSEC_PER_SEC;
3482 u64 divisor, dividend;
3484 int count_fls, nsec_fls, frequency_fls, sec_fls;
3486 count_fls = fls64(count);
3487 nsec_fls = fls64(nsec);
3488 frequency_fls = fls64(frequency);
3492 * We got @count in @nsec, with a target of sample_freq HZ
3493 * the target period becomes:
3496 * period = -------------------
3497 * @nsec * sample_freq
3502 * Reduce accuracy by one bit such that @a and @b converge
3503 * to a similar magnitude.
3505 #define REDUCE_FLS(a, b) \
3507 if (a##_fls > b##_fls) { \
3517 * Reduce accuracy until either term fits in a u64, then proceed with
3518 * the other, so that finally we can do a u64/u64 division.
3520 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3521 REDUCE_FLS(nsec, frequency);
3522 REDUCE_FLS(sec, count);
3525 if (count_fls + sec_fls > 64) {
3526 divisor = nsec * frequency;
3528 while (count_fls + sec_fls > 64) {
3529 REDUCE_FLS(count, sec);
3533 dividend = count * sec;
3535 dividend = count * sec;
3537 while (nsec_fls + frequency_fls > 64) {
3538 REDUCE_FLS(nsec, frequency);
3542 divisor = nsec * frequency;
3548 return div64_u64(dividend, divisor);
3551 static DEFINE_PER_CPU(int, perf_throttled_count);
3552 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3554 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3556 struct hw_perf_event *hwc = &event->hw;
3557 s64 period, sample_period;
3560 period = perf_calculate_period(event, nsec, count);
3562 delta = (s64)(period - hwc->sample_period);
3563 delta = (delta + 7) / 8; /* low pass filter */
3565 sample_period = hwc->sample_period + delta;
3570 hwc->sample_period = sample_period;
3572 if (local64_read(&hwc->period_left) > 8*sample_period) {
3574 event->pmu->stop(event, PERF_EF_UPDATE);
3576 local64_set(&hwc->period_left, 0);
3579 event->pmu->start(event, PERF_EF_RELOAD);
3584 * combine freq adjustment with unthrottling to avoid two passes over the
3585 * events. At the same time, make sure, having freq events does not change
3586 * the rate of unthrottling as that would introduce bias.
3588 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3591 struct perf_event *event;
3592 struct hw_perf_event *hwc;
3593 u64 now, period = TICK_NSEC;
3597 * only need to iterate over all events iff:
3598 * - context have events in frequency mode (needs freq adjust)
3599 * - there are events to unthrottle on this cpu
3601 if (!(ctx->nr_freq || needs_unthr))
3604 raw_spin_lock(&ctx->lock);
3605 perf_pmu_disable(ctx->pmu);
3607 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3608 if (event->state != PERF_EVENT_STATE_ACTIVE)
3611 if (!event_filter_match(event))
3614 perf_pmu_disable(event->pmu);
3618 if (hwc->interrupts == MAX_INTERRUPTS) {
3619 hwc->interrupts = 0;
3620 perf_log_throttle(event, 1);
3621 event->pmu->start(event, 0);
3624 if (!event->attr.freq || !event->attr.sample_freq)
3628 * stop the event and update event->count
3630 event->pmu->stop(event, PERF_EF_UPDATE);
3632 now = local64_read(&event->count);
3633 delta = now - hwc->freq_count_stamp;
3634 hwc->freq_count_stamp = now;
3638 * reload only if value has changed
3639 * we have stopped the event so tell that
3640 * to perf_adjust_period() to avoid stopping it
3644 perf_adjust_period(event, period, delta, false);
3646 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3648 perf_pmu_enable(event->pmu);
3651 perf_pmu_enable(ctx->pmu);
3652 raw_spin_unlock(&ctx->lock);
3656 * Move @event to the tail of the @ctx's elegible events.
3658 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3661 * Rotate the first entry last of non-pinned groups. Rotation might be
3662 * disabled by the inheritance code.
3664 if (ctx->rotate_disable)
3667 perf_event_groups_delete(&ctx->flexible_groups, event);
3668 perf_event_groups_insert(&ctx->flexible_groups, event);
3671 static inline struct perf_event *
3672 ctx_first_active(struct perf_event_context *ctx)
3674 return list_first_entry_or_null(&ctx->flexible_active,
3675 struct perf_event, active_list);
3678 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3680 struct perf_event *cpu_event = NULL, *task_event = NULL;
3681 bool cpu_rotate = false, task_rotate = false;
3682 struct perf_event_context *ctx = NULL;
3685 * Since we run this from IRQ context, nobody can install new
3686 * events, thus the event count values are stable.
3689 if (cpuctx->ctx.nr_events) {
3690 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3694 ctx = cpuctx->task_ctx;
3695 if (ctx && ctx->nr_events) {
3696 if (ctx->nr_events != ctx->nr_active)
3700 if (!(cpu_rotate || task_rotate))
3703 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3704 perf_pmu_disable(cpuctx->ctx.pmu);
3707 task_event = ctx_first_active(ctx);
3709 cpu_event = ctx_first_active(&cpuctx->ctx);
3712 * As per the order given at ctx_resched() first 'pop' task flexible
3713 * and then, if needed CPU flexible.
3715 if (task_event || (ctx && cpu_event))
3716 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3718 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3721 rotate_ctx(ctx, task_event);
3723 rotate_ctx(&cpuctx->ctx, cpu_event);
3725 perf_event_sched_in(cpuctx, ctx, current);
3727 perf_pmu_enable(cpuctx->ctx.pmu);
3728 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3733 void perf_event_task_tick(void)
3735 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3736 struct perf_event_context *ctx, *tmp;
3739 lockdep_assert_irqs_disabled();
3741 __this_cpu_inc(perf_throttled_seq);
3742 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3743 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3745 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3746 perf_adjust_freq_unthr_context(ctx, throttled);
3749 static int event_enable_on_exec(struct perf_event *event,
3750 struct perf_event_context *ctx)
3752 if (!event->attr.enable_on_exec)
3755 event->attr.enable_on_exec = 0;
3756 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3759 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3765 * Enable all of a task's events that have been marked enable-on-exec.
3766 * This expects task == current.
3768 static void perf_event_enable_on_exec(int ctxn)
3770 struct perf_event_context *ctx, *clone_ctx = NULL;
3771 enum event_type_t event_type = 0;
3772 struct perf_cpu_context *cpuctx;
3773 struct perf_event *event;
3774 unsigned long flags;
3777 local_irq_save(flags);
3778 ctx = current->perf_event_ctxp[ctxn];
3779 if (!ctx || !ctx->nr_events)
3782 cpuctx = __get_cpu_context(ctx);
3783 perf_ctx_lock(cpuctx, ctx);
3784 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3785 list_for_each_entry(event, &ctx->event_list, event_entry) {
3786 enabled |= event_enable_on_exec(event, ctx);
3787 event_type |= get_event_type(event);
3791 * Unclone and reschedule this context if we enabled any event.
3794 clone_ctx = unclone_ctx(ctx);
3795 ctx_resched(cpuctx, ctx, event_type);
3797 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3799 perf_ctx_unlock(cpuctx, ctx);
3802 local_irq_restore(flags);
3808 struct perf_read_data {
3809 struct perf_event *event;
3814 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3816 u16 local_pkg, event_pkg;
3818 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3819 int local_cpu = smp_processor_id();
3821 event_pkg = topology_physical_package_id(event_cpu);
3822 local_pkg = topology_physical_package_id(local_cpu);
3824 if (event_pkg == local_pkg)
3832 * Cross CPU call to read the hardware event
3834 static void __perf_event_read(void *info)
3836 struct perf_read_data *data = info;
3837 struct perf_event *sub, *event = data->event;
3838 struct perf_event_context *ctx = event->ctx;
3839 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3840 struct pmu *pmu = event->pmu;
3843 * If this is a task context, we need to check whether it is
3844 * the current task context of this cpu. If not it has been
3845 * scheduled out before the smp call arrived. In that case
3846 * event->count would have been updated to a recent sample
3847 * when the event was scheduled out.
3849 if (ctx->task && cpuctx->task_ctx != ctx)
3852 raw_spin_lock(&ctx->lock);
3853 if (ctx->is_active & EVENT_TIME) {
3854 update_context_time(ctx);
3855 update_cgrp_time_from_event(event);
3858 perf_event_update_time(event);
3860 perf_event_update_sibling_time(event);
3862 if (event->state != PERF_EVENT_STATE_ACTIVE)
3871 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3875 for_each_sibling_event(sub, event) {
3876 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3878 * Use sibling's PMU rather than @event's since
3879 * sibling could be on different (eg: software) PMU.
3881 sub->pmu->read(sub);
3885 data->ret = pmu->commit_txn(pmu);
3888 raw_spin_unlock(&ctx->lock);
3891 static inline u64 perf_event_count(struct perf_event *event)
3893 return local64_read(&event->count) + atomic64_read(&event->child_count);
3897 * NMI-safe method to read a local event, that is an event that
3899 * - either for the current task, or for this CPU
3900 * - does not have inherit set, for inherited task events
3901 * will not be local and we cannot read them atomically
3902 * - must not have a pmu::count method
3904 int perf_event_read_local(struct perf_event *event, u64 *value,
3905 u64 *enabled, u64 *running)
3907 unsigned long flags;
3911 * Disabling interrupts avoids all counter scheduling (context
3912 * switches, timer based rotation and IPIs).
3914 local_irq_save(flags);
3917 * It must not be an event with inherit set, we cannot read
3918 * all child counters from atomic context.
3920 if (event->attr.inherit) {
3925 /* If this is a per-task event, it must be for current */
3926 if ((event->attach_state & PERF_ATTACH_TASK) &&
3927 event->hw.target != current) {
3932 /* If this is a per-CPU event, it must be for this CPU */
3933 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3934 event->cpu != smp_processor_id()) {
3939 /* If this is a pinned event it must be running on this CPU */
3940 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3946 * If the event is currently on this CPU, its either a per-task event,
3947 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3950 if (event->oncpu == smp_processor_id())
3951 event->pmu->read(event);
3953 *value = local64_read(&event->count);
3954 if (enabled || running) {
3955 u64 now = event->shadow_ctx_time + perf_clock();
3956 u64 __enabled, __running;
3958 __perf_update_times(event, now, &__enabled, &__running);
3960 *enabled = __enabled;
3962 *running = __running;
3965 local_irq_restore(flags);
3970 static int perf_event_read(struct perf_event *event, bool group)
3972 enum perf_event_state state = READ_ONCE(event->state);
3973 int event_cpu, ret = 0;
3976 * If event is enabled and currently active on a CPU, update the
3977 * value in the event structure:
3980 if (state == PERF_EVENT_STATE_ACTIVE) {
3981 struct perf_read_data data;
3984 * Orders the ->state and ->oncpu loads such that if we see
3985 * ACTIVE we must also see the right ->oncpu.
3987 * Matches the smp_wmb() from event_sched_in().
3991 event_cpu = READ_ONCE(event->oncpu);
3992 if ((unsigned)event_cpu >= nr_cpu_ids)
3995 data = (struct perf_read_data){
4002 event_cpu = __perf_event_read_cpu(event, event_cpu);
4005 * Purposely ignore the smp_call_function_single() return
4008 * If event_cpu isn't a valid CPU it means the event got
4009 * scheduled out and that will have updated the event count.
4011 * Therefore, either way, we'll have an up-to-date event count
4014 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4018 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4019 struct perf_event_context *ctx = event->ctx;
4020 unsigned long flags;
4022 raw_spin_lock_irqsave(&ctx->lock, flags);
4023 state = event->state;
4024 if (state != PERF_EVENT_STATE_INACTIVE) {
4025 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4030 * May read while context is not active (e.g., thread is
4031 * blocked), in that case we cannot update context time
4033 if (ctx->is_active & EVENT_TIME) {
4034 update_context_time(ctx);
4035 update_cgrp_time_from_event(event);
4038 perf_event_update_time(event);
4040 perf_event_update_sibling_time(event);
4041 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4048 * Initialize the perf_event context in a task_struct:
4050 static void __perf_event_init_context(struct perf_event_context *ctx)
4052 raw_spin_lock_init(&ctx->lock);
4053 mutex_init(&ctx->mutex);
4054 INIT_LIST_HEAD(&ctx->active_ctx_list);
4055 perf_event_groups_init(&ctx->pinned_groups);
4056 perf_event_groups_init(&ctx->flexible_groups);
4057 INIT_LIST_HEAD(&ctx->event_list);
4058 INIT_LIST_HEAD(&ctx->pinned_active);
4059 INIT_LIST_HEAD(&ctx->flexible_active);
4060 refcount_set(&ctx->refcount, 1);
4063 static struct perf_event_context *
4064 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4066 struct perf_event_context *ctx;
4068 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4072 __perf_event_init_context(ctx);
4075 get_task_struct(task);
4082 static struct task_struct *
4083 find_lively_task_by_vpid(pid_t vpid)
4085 struct task_struct *task;
4091 task = find_task_by_vpid(vpid);
4093 get_task_struct(task);
4097 return ERR_PTR(-ESRCH);
4103 * Returns a matching context with refcount and pincount.
4105 static struct perf_event_context *
4106 find_get_context(struct pmu *pmu, struct task_struct *task,
4107 struct perf_event *event)
4109 struct perf_event_context *ctx, *clone_ctx = NULL;
4110 struct perf_cpu_context *cpuctx;
4111 void *task_ctx_data = NULL;
4112 unsigned long flags;
4114 int cpu = event->cpu;
4117 /* Must be root to operate on a CPU event: */
4118 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4119 return ERR_PTR(-EACCES);
4121 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4130 ctxn = pmu->task_ctx_nr;
4134 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4135 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4136 if (!task_ctx_data) {
4143 ctx = perf_lock_task_context(task, ctxn, &flags);
4145 clone_ctx = unclone_ctx(ctx);
4148 if (task_ctx_data && !ctx->task_ctx_data) {
4149 ctx->task_ctx_data = task_ctx_data;
4150 task_ctx_data = NULL;
4152 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4157 ctx = alloc_perf_context(pmu, task);
4162 if (task_ctx_data) {
4163 ctx->task_ctx_data = task_ctx_data;
4164 task_ctx_data = NULL;
4168 mutex_lock(&task->perf_event_mutex);
4170 * If it has already passed perf_event_exit_task().
4171 * we must see PF_EXITING, it takes this mutex too.
4173 if (task->flags & PF_EXITING)
4175 else if (task->perf_event_ctxp[ctxn])
4180 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4182 mutex_unlock(&task->perf_event_mutex);
4184 if (unlikely(err)) {
4193 kfree(task_ctx_data);
4197 kfree(task_ctx_data);
4198 return ERR_PTR(err);
4201 static void perf_event_free_filter(struct perf_event *event);
4202 static void perf_event_free_bpf_prog(struct perf_event *event);
4204 static void free_event_rcu(struct rcu_head *head)
4206 struct perf_event *event;
4208 event = container_of(head, struct perf_event, rcu_head);
4210 put_pid_ns(event->ns);
4211 perf_event_free_filter(event);
4215 static void ring_buffer_attach(struct perf_event *event,
4216 struct ring_buffer *rb);
4218 static void detach_sb_event(struct perf_event *event)
4220 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4222 raw_spin_lock(&pel->lock);
4223 list_del_rcu(&event->sb_list);
4224 raw_spin_unlock(&pel->lock);
4227 static bool is_sb_event(struct perf_event *event)
4229 struct perf_event_attr *attr = &event->attr;
4234 if (event->attach_state & PERF_ATTACH_TASK)
4237 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4238 attr->comm || attr->comm_exec ||
4239 attr->task || attr->ksymbol ||
4240 attr->context_switch)
4245 static void unaccount_pmu_sb_event(struct perf_event *event)
4247 if (is_sb_event(event))
4248 detach_sb_event(event);
4251 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4256 if (is_cgroup_event(event))
4257 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4260 #ifdef CONFIG_NO_HZ_FULL
4261 static DEFINE_SPINLOCK(nr_freq_lock);
4264 static void unaccount_freq_event_nohz(void)
4266 #ifdef CONFIG_NO_HZ_FULL
4267 spin_lock(&nr_freq_lock);
4268 if (atomic_dec_and_test(&nr_freq_events))
4269 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4270 spin_unlock(&nr_freq_lock);
4274 static void unaccount_freq_event(void)
4276 if (tick_nohz_full_enabled())
4277 unaccount_freq_event_nohz();
4279 atomic_dec(&nr_freq_events);
4282 static void unaccount_event(struct perf_event *event)
4289 if (event->attach_state & PERF_ATTACH_TASK)
4291 if (event->attr.mmap || event->attr.mmap_data)
4292 atomic_dec(&nr_mmap_events);
4293 if (event->attr.comm)
4294 atomic_dec(&nr_comm_events);
4295 if (event->attr.namespaces)
4296 atomic_dec(&nr_namespaces_events);
4297 if (event->attr.task)
4298 atomic_dec(&nr_task_events);
4299 if (event->attr.freq)
4300 unaccount_freq_event();
4301 if (event->attr.context_switch) {
4303 atomic_dec(&nr_switch_events);
4305 if (is_cgroup_event(event))
4307 if (has_branch_stack(event))
4309 if (event->attr.ksymbol)
4310 atomic_dec(&nr_ksymbol_events);
4311 if (event->attr.bpf_event)
4312 atomic_dec(&nr_bpf_events);
4315 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4316 schedule_delayed_work(&perf_sched_work, HZ);
4319 unaccount_event_cpu(event, event->cpu);
4321 unaccount_pmu_sb_event(event);
4324 static void perf_sched_delayed(struct work_struct *work)
4326 mutex_lock(&perf_sched_mutex);
4327 if (atomic_dec_and_test(&perf_sched_count))
4328 static_branch_disable(&perf_sched_events);
4329 mutex_unlock(&perf_sched_mutex);
4333 * The following implement mutual exclusion of events on "exclusive" pmus
4334 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4335 * at a time, so we disallow creating events that might conflict, namely:
4337 * 1) cpu-wide events in the presence of per-task events,
4338 * 2) per-task events in the presence of cpu-wide events,
4339 * 3) two matching events on the same context.
4341 * The former two cases are handled in the allocation path (perf_event_alloc(),
4342 * _free_event()), the latter -- before the first perf_install_in_context().
4344 static int exclusive_event_init(struct perf_event *event)
4346 struct pmu *pmu = event->pmu;
4348 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4352 * Prevent co-existence of per-task and cpu-wide events on the
4353 * same exclusive pmu.
4355 * Negative pmu::exclusive_cnt means there are cpu-wide
4356 * events on this "exclusive" pmu, positive means there are
4359 * Since this is called in perf_event_alloc() path, event::ctx
4360 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4361 * to mean "per-task event", because unlike other attach states it
4362 * never gets cleared.
4364 if (event->attach_state & PERF_ATTACH_TASK) {
4365 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4368 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4375 static void exclusive_event_destroy(struct perf_event *event)
4377 struct pmu *pmu = event->pmu;
4379 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4382 /* see comment in exclusive_event_init() */
4383 if (event->attach_state & PERF_ATTACH_TASK)
4384 atomic_dec(&pmu->exclusive_cnt);
4386 atomic_inc(&pmu->exclusive_cnt);
4389 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4391 if ((e1->pmu == e2->pmu) &&
4392 (e1->cpu == e2->cpu ||
4399 /* Called under the same ctx::mutex as perf_install_in_context() */
4400 static bool exclusive_event_installable(struct perf_event *event,
4401 struct perf_event_context *ctx)
4403 struct perf_event *iter_event;
4404 struct pmu *pmu = event->pmu;
4406 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4409 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4410 if (exclusive_event_match(iter_event, event))
4417 static void perf_addr_filters_splice(struct perf_event *event,
4418 struct list_head *head);
4420 static void _free_event(struct perf_event *event)
4422 irq_work_sync(&event->pending);
4424 unaccount_event(event);
4428 * Can happen when we close an event with re-directed output.
4430 * Since we have a 0 refcount, perf_mmap_close() will skip
4431 * over us; possibly making our ring_buffer_put() the last.
4433 mutex_lock(&event->mmap_mutex);
4434 ring_buffer_attach(event, NULL);
4435 mutex_unlock(&event->mmap_mutex);
4438 if (is_cgroup_event(event))
4439 perf_detach_cgroup(event);
4441 if (!event->parent) {
4442 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4443 put_callchain_buffers();
4446 perf_event_free_bpf_prog(event);
4447 perf_addr_filters_splice(event, NULL);
4448 kfree(event->addr_filters_offs);
4451 event->destroy(event);
4454 put_ctx(event->ctx);
4456 if (event->hw.target)
4457 put_task_struct(event->hw.target);
4459 exclusive_event_destroy(event);
4460 module_put(event->pmu->module);
4462 call_rcu(&event->rcu_head, free_event_rcu);
4466 * Used to free events which have a known refcount of 1, such as in error paths
4467 * where the event isn't exposed yet and inherited events.
4469 static void free_event(struct perf_event *event)
4471 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4472 "unexpected event refcount: %ld; ptr=%p\n",
4473 atomic_long_read(&event->refcount), event)) {
4474 /* leak to avoid use-after-free */
4482 * Remove user event from the owner task.
4484 static void perf_remove_from_owner(struct perf_event *event)
4486 struct task_struct *owner;
4490 * Matches the smp_store_release() in perf_event_exit_task(). If we
4491 * observe !owner it means the list deletion is complete and we can
4492 * indeed free this event, otherwise we need to serialize on
4493 * owner->perf_event_mutex.
4495 owner = READ_ONCE(event->owner);
4498 * Since delayed_put_task_struct() also drops the last
4499 * task reference we can safely take a new reference
4500 * while holding the rcu_read_lock().
4502 get_task_struct(owner);
4508 * If we're here through perf_event_exit_task() we're already
4509 * holding ctx->mutex which would be an inversion wrt. the
4510 * normal lock order.
4512 * However we can safely take this lock because its the child
4515 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4518 * We have to re-check the event->owner field, if it is cleared
4519 * we raced with perf_event_exit_task(), acquiring the mutex
4520 * ensured they're done, and we can proceed with freeing the
4524 list_del_init(&event->owner_entry);
4525 smp_store_release(&event->owner, NULL);
4527 mutex_unlock(&owner->perf_event_mutex);
4528 put_task_struct(owner);
4532 static void put_event(struct perf_event *event)
4534 if (!atomic_long_dec_and_test(&event->refcount))
4541 * Kill an event dead; while event:refcount will preserve the event
4542 * object, it will not preserve its functionality. Once the last 'user'
4543 * gives up the object, we'll destroy the thing.
4545 int perf_event_release_kernel(struct perf_event *event)
4547 struct perf_event_context *ctx = event->ctx;
4548 struct perf_event *child, *tmp;
4549 LIST_HEAD(free_list);
4552 * If we got here through err_file: fput(event_file); we will not have
4553 * attached to a context yet.
4556 WARN_ON_ONCE(event->attach_state &
4557 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4561 if (!is_kernel_event(event))
4562 perf_remove_from_owner(event);
4564 ctx = perf_event_ctx_lock(event);
4565 WARN_ON_ONCE(ctx->parent_ctx);
4566 perf_remove_from_context(event, DETACH_GROUP);
4568 raw_spin_lock_irq(&ctx->lock);
4570 * Mark this event as STATE_DEAD, there is no external reference to it
4573 * Anybody acquiring event->child_mutex after the below loop _must_
4574 * also see this, most importantly inherit_event() which will avoid
4575 * placing more children on the list.
4577 * Thus this guarantees that we will in fact observe and kill _ALL_
4580 event->state = PERF_EVENT_STATE_DEAD;
4581 raw_spin_unlock_irq(&ctx->lock);
4583 perf_event_ctx_unlock(event, ctx);
4586 mutex_lock(&event->child_mutex);
4587 list_for_each_entry(child, &event->child_list, child_list) {
4590 * Cannot change, child events are not migrated, see the
4591 * comment with perf_event_ctx_lock_nested().
4593 ctx = READ_ONCE(child->ctx);
4595 * Since child_mutex nests inside ctx::mutex, we must jump
4596 * through hoops. We start by grabbing a reference on the ctx.
4598 * Since the event cannot get freed while we hold the
4599 * child_mutex, the context must also exist and have a !0
4605 * Now that we have a ctx ref, we can drop child_mutex, and
4606 * acquire ctx::mutex without fear of it going away. Then we
4607 * can re-acquire child_mutex.
4609 mutex_unlock(&event->child_mutex);
4610 mutex_lock(&ctx->mutex);
4611 mutex_lock(&event->child_mutex);
4614 * Now that we hold ctx::mutex and child_mutex, revalidate our
4615 * state, if child is still the first entry, it didn't get freed
4616 * and we can continue doing so.
4618 tmp = list_first_entry_or_null(&event->child_list,
4619 struct perf_event, child_list);
4621 perf_remove_from_context(child, DETACH_GROUP);
4622 list_move(&child->child_list, &free_list);
4624 * This matches the refcount bump in inherit_event();
4625 * this can't be the last reference.
4630 mutex_unlock(&event->child_mutex);
4631 mutex_unlock(&ctx->mutex);
4635 mutex_unlock(&event->child_mutex);
4637 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4638 list_del(&child->child_list);
4643 put_event(event); /* Must be the 'last' reference */
4646 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4649 * Called when the last reference to the file is gone.
4651 static int perf_release(struct inode *inode, struct file *file)
4653 perf_event_release_kernel(file->private_data);
4657 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4659 struct perf_event *child;
4665 mutex_lock(&event->child_mutex);
4667 (void)perf_event_read(event, false);
4668 total += perf_event_count(event);
4670 *enabled += event->total_time_enabled +
4671 atomic64_read(&event->child_total_time_enabled);
4672 *running += event->total_time_running +
4673 atomic64_read(&event->child_total_time_running);
4675 list_for_each_entry(child, &event->child_list, child_list) {
4676 (void)perf_event_read(child, false);
4677 total += perf_event_count(child);
4678 *enabled += child->total_time_enabled;
4679 *running += child->total_time_running;
4681 mutex_unlock(&event->child_mutex);
4686 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4688 struct perf_event_context *ctx;
4691 ctx = perf_event_ctx_lock(event);
4692 count = __perf_event_read_value(event, enabled, running);
4693 perf_event_ctx_unlock(event, ctx);
4697 EXPORT_SYMBOL_GPL(perf_event_read_value);
4699 static int __perf_read_group_add(struct perf_event *leader,
4700 u64 read_format, u64 *values)
4702 struct perf_event_context *ctx = leader->ctx;
4703 struct perf_event *sub;
4704 unsigned long flags;
4705 int n = 1; /* skip @nr */
4708 ret = perf_event_read(leader, true);
4712 raw_spin_lock_irqsave(&ctx->lock, flags);
4715 * Since we co-schedule groups, {enabled,running} times of siblings
4716 * will be identical to those of the leader, so we only publish one
4719 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4720 values[n++] += leader->total_time_enabled +
4721 atomic64_read(&leader->child_total_time_enabled);
4724 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4725 values[n++] += leader->total_time_running +
4726 atomic64_read(&leader->child_total_time_running);
4730 * Write {count,id} tuples for every sibling.
4732 values[n++] += perf_event_count(leader);
4733 if (read_format & PERF_FORMAT_ID)
4734 values[n++] = primary_event_id(leader);
4736 for_each_sibling_event(sub, leader) {
4737 values[n++] += perf_event_count(sub);
4738 if (read_format & PERF_FORMAT_ID)
4739 values[n++] = primary_event_id(sub);
4742 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4746 static int perf_read_group(struct perf_event *event,
4747 u64 read_format, char __user *buf)
4749 struct perf_event *leader = event->group_leader, *child;
4750 struct perf_event_context *ctx = leader->ctx;
4754 lockdep_assert_held(&ctx->mutex);
4756 values = kzalloc(event->read_size, GFP_KERNEL);
4760 values[0] = 1 + leader->nr_siblings;
4763 * By locking the child_mutex of the leader we effectively
4764 * lock the child list of all siblings.. XXX explain how.
4766 mutex_lock(&leader->child_mutex);
4768 ret = __perf_read_group_add(leader, read_format, values);
4772 list_for_each_entry(child, &leader->child_list, child_list) {
4773 ret = __perf_read_group_add(child, read_format, values);
4778 mutex_unlock(&leader->child_mutex);
4780 ret = event->read_size;
4781 if (copy_to_user(buf, values, event->read_size))
4786 mutex_unlock(&leader->child_mutex);
4792 static int perf_read_one(struct perf_event *event,
4793 u64 read_format, char __user *buf)
4795 u64 enabled, running;
4799 values[n++] = __perf_event_read_value(event, &enabled, &running);
4800 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4801 values[n++] = enabled;
4802 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4803 values[n++] = running;
4804 if (read_format & PERF_FORMAT_ID)
4805 values[n++] = primary_event_id(event);
4807 if (copy_to_user(buf, values, n * sizeof(u64)))
4810 return n * sizeof(u64);
4813 static bool is_event_hup(struct perf_event *event)
4817 if (event->state > PERF_EVENT_STATE_EXIT)
4820 mutex_lock(&event->child_mutex);
4821 no_children = list_empty(&event->child_list);
4822 mutex_unlock(&event->child_mutex);
4827 * Read the performance event - simple non blocking version for now
4830 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4832 u64 read_format = event->attr.read_format;
4836 * Return end-of-file for a read on an event that is in
4837 * error state (i.e. because it was pinned but it couldn't be
4838 * scheduled on to the CPU at some point).
4840 if (event->state == PERF_EVENT_STATE_ERROR)
4843 if (count < event->read_size)
4846 WARN_ON_ONCE(event->ctx->parent_ctx);
4847 if (read_format & PERF_FORMAT_GROUP)
4848 ret = perf_read_group(event, read_format, buf);
4850 ret = perf_read_one(event, read_format, buf);
4856 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4858 struct perf_event *event = file->private_data;
4859 struct perf_event_context *ctx;
4862 ctx = perf_event_ctx_lock(event);
4863 ret = __perf_read(event, buf, count);
4864 perf_event_ctx_unlock(event, ctx);
4869 static __poll_t perf_poll(struct file *file, poll_table *wait)
4871 struct perf_event *event = file->private_data;
4872 struct ring_buffer *rb;
4873 __poll_t events = EPOLLHUP;
4875 poll_wait(file, &event->waitq, wait);
4877 if (is_event_hup(event))
4881 * Pin the event->rb by taking event->mmap_mutex; otherwise
4882 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4884 mutex_lock(&event->mmap_mutex);
4887 events = atomic_xchg(&rb->poll, 0);
4888 mutex_unlock(&event->mmap_mutex);
4892 static void _perf_event_reset(struct perf_event *event)
4894 (void)perf_event_read(event, false);
4895 local64_set(&event->count, 0);
4896 perf_event_update_userpage(event);
4900 * Holding the top-level event's child_mutex means that any
4901 * descendant process that has inherited this event will block
4902 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4903 * task existence requirements of perf_event_enable/disable.
4905 static void perf_event_for_each_child(struct perf_event *event,
4906 void (*func)(struct perf_event *))
4908 struct perf_event *child;
4910 WARN_ON_ONCE(event->ctx->parent_ctx);
4912 mutex_lock(&event->child_mutex);
4914 list_for_each_entry(child, &event->child_list, child_list)
4916 mutex_unlock(&event->child_mutex);
4919 static void perf_event_for_each(struct perf_event *event,
4920 void (*func)(struct perf_event *))
4922 struct perf_event_context *ctx = event->ctx;
4923 struct perf_event *sibling;
4925 lockdep_assert_held(&ctx->mutex);
4927 event = event->group_leader;
4929 perf_event_for_each_child(event, func);
4930 for_each_sibling_event(sibling, event)
4931 perf_event_for_each_child(sibling, func);
4934 static void __perf_event_period(struct perf_event *event,
4935 struct perf_cpu_context *cpuctx,
4936 struct perf_event_context *ctx,
4939 u64 value = *((u64 *)info);
4942 if (event->attr.freq) {
4943 event->attr.sample_freq = value;
4945 event->attr.sample_period = value;
4946 event->hw.sample_period = value;
4949 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4951 perf_pmu_disable(ctx->pmu);
4953 * We could be throttled; unthrottle now to avoid the tick
4954 * trying to unthrottle while we already re-started the event.
4956 if (event->hw.interrupts == MAX_INTERRUPTS) {
4957 event->hw.interrupts = 0;
4958 perf_log_throttle(event, 1);
4960 event->pmu->stop(event, PERF_EF_UPDATE);
4963 local64_set(&event->hw.period_left, 0);
4966 event->pmu->start(event, PERF_EF_RELOAD);
4967 perf_pmu_enable(ctx->pmu);
4971 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4975 if (!is_sampling_event(event))
4978 if (copy_from_user(&value, arg, sizeof(value)))
4984 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4987 event_function_call(event, __perf_event_period, &value);
4992 static const struct file_operations perf_fops;
4994 static inline int perf_fget_light(int fd, struct fd *p)
4996 struct fd f = fdget(fd);
5000 if (f.file->f_op != &perf_fops) {
5008 static int perf_event_set_output(struct perf_event *event,
5009 struct perf_event *output_event);
5010 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5011 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5012 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5013 struct perf_event_attr *attr);
5015 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5017 void (*func)(struct perf_event *);
5021 case PERF_EVENT_IOC_ENABLE:
5022 func = _perf_event_enable;
5024 case PERF_EVENT_IOC_DISABLE:
5025 func = _perf_event_disable;
5027 case PERF_EVENT_IOC_RESET:
5028 func = _perf_event_reset;
5031 case PERF_EVENT_IOC_REFRESH:
5032 return _perf_event_refresh(event, arg);
5034 case PERF_EVENT_IOC_PERIOD:
5035 return perf_event_period(event, (u64 __user *)arg);
5037 case PERF_EVENT_IOC_ID:
5039 u64 id = primary_event_id(event);
5041 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5046 case PERF_EVENT_IOC_SET_OUTPUT:
5050 struct perf_event *output_event;
5052 ret = perf_fget_light(arg, &output);
5055 output_event = output.file->private_data;
5056 ret = perf_event_set_output(event, output_event);
5059 ret = perf_event_set_output(event, NULL);
5064 case PERF_EVENT_IOC_SET_FILTER:
5065 return perf_event_set_filter(event, (void __user *)arg);
5067 case PERF_EVENT_IOC_SET_BPF:
5068 return perf_event_set_bpf_prog(event, arg);
5070 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5071 struct ring_buffer *rb;
5074 rb = rcu_dereference(event->rb);
5075 if (!rb || !rb->nr_pages) {
5079 rb_toggle_paused(rb, !!arg);
5084 case PERF_EVENT_IOC_QUERY_BPF:
5085 return perf_event_query_prog_array(event, (void __user *)arg);
5087 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5088 struct perf_event_attr new_attr;
5089 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5095 return perf_event_modify_attr(event, &new_attr);
5101 if (flags & PERF_IOC_FLAG_GROUP)
5102 perf_event_for_each(event, func);
5104 perf_event_for_each_child(event, func);
5109 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5111 struct perf_event *event = file->private_data;
5112 struct perf_event_context *ctx;
5115 ctx = perf_event_ctx_lock(event);
5116 ret = _perf_ioctl(event, cmd, arg);
5117 perf_event_ctx_unlock(event, ctx);
5122 #ifdef CONFIG_COMPAT
5123 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5126 switch (_IOC_NR(cmd)) {
5127 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5128 case _IOC_NR(PERF_EVENT_IOC_ID):
5129 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5130 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5131 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5132 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5133 cmd &= ~IOCSIZE_MASK;
5134 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5138 return perf_ioctl(file, cmd, arg);
5141 # define perf_compat_ioctl NULL
5144 int perf_event_task_enable(void)
5146 struct perf_event_context *ctx;
5147 struct perf_event *event;
5149 mutex_lock(¤t->perf_event_mutex);
5150 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5151 ctx = perf_event_ctx_lock(event);
5152 perf_event_for_each_child(event, _perf_event_enable);
5153 perf_event_ctx_unlock(event, ctx);
5155 mutex_unlock(¤t->perf_event_mutex);
5160 int perf_event_task_disable(void)
5162 struct perf_event_context *ctx;
5163 struct perf_event *event;
5165 mutex_lock(¤t->perf_event_mutex);
5166 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5167 ctx = perf_event_ctx_lock(event);
5168 perf_event_for_each_child(event, _perf_event_disable);
5169 perf_event_ctx_unlock(event, ctx);
5171 mutex_unlock(¤t->perf_event_mutex);
5176 static int perf_event_index(struct perf_event *event)
5178 if (event->hw.state & PERF_HES_STOPPED)
5181 if (event->state != PERF_EVENT_STATE_ACTIVE)
5184 return event->pmu->event_idx(event);
5187 static void calc_timer_values(struct perf_event *event,
5194 *now = perf_clock();
5195 ctx_time = event->shadow_ctx_time + *now;
5196 __perf_update_times(event, ctx_time, enabled, running);
5199 static void perf_event_init_userpage(struct perf_event *event)
5201 struct perf_event_mmap_page *userpg;
5202 struct ring_buffer *rb;
5205 rb = rcu_dereference(event->rb);
5209 userpg = rb->user_page;
5211 /* Allow new userspace to detect that bit 0 is deprecated */
5212 userpg->cap_bit0_is_deprecated = 1;
5213 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5214 userpg->data_offset = PAGE_SIZE;
5215 userpg->data_size = perf_data_size(rb);
5221 void __weak arch_perf_update_userpage(
5222 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5227 * Callers need to ensure there can be no nesting of this function, otherwise
5228 * the seqlock logic goes bad. We can not serialize this because the arch
5229 * code calls this from NMI context.
5231 void perf_event_update_userpage(struct perf_event *event)
5233 struct perf_event_mmap_page *userpg;
5234 struct ring_buffer *rb;
5235 u64 enabled, running, now;
5238 rb = rcu_dereference(event->rb);
5243 * compute total_time_enabled, total_time_running
5244 * based on snapshot values taken when the event
5245 * was last scheduled in.
5247 * we cannot simply called update_context_time()
5248 * because of locking issue as we can be called in
5251 calc_timer_values(event, &now, &enabled, &running);
5253 userpg = rb->user_page;
5255 * Disable preemption to guarantee consistent time stamps are stored to
5261 userpg->index = perf_event_index(event);
5262 userpg->offset = perf_event_count(event);
5264 userpg->offset -= local64_read(&event->hw.prev_count);
5266 userpg->time_enabled = enabled +
5267 atomic64_read(&event->child_total_time_enabled);
5269 userpg->time_running = running +
5270 atomic64_read(&event->child_total_time_running);
5272 arch_perf_update_userpage(event, userpg, now);
5280 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5282 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5284 struct perf_event *event = vmf->vma->vm_file->private_data;
5285 struct ring_buffer *rb;
5286 vm_fault_t ret = VM_FAULT_SIGBUS;
5288 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5289 if (vmf->pgoff == 0)
5295 rb = rcu_dereference(event->rb);
5299 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5302 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5306 get_page(vmf->page);
5307 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5308 vmf->page->index = vmf->pgoff;
5317 static void ring_buffer_attach(struct perf_event *event,
5318 struct ring_buffer *rb)
5320 struct ring_buffer *old_rb = NULL;
5321 unsigned long flags;
5325 * Should be impossible, we set this when removing
5326 * event->rb_entry and wait/clear when adding event->rb_entry.
5328 WARN_ON_ONCE(event->rcu_pending);
5331 spin_lock_irqsave(&old_rb->event_lock, flags);
5332 list_del_rcu(&event->rb_entry);
5333 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5335 event->rcu_batches = get_state_synchronize_rcu();
5336 event->rcu_pending = 1;
5340 if (event->rcu_pending) {
5341 cond_synchronize_rcu(event->rcu_batches);
5342 event->rcu_pending = 0;
5345 spin_lock_irqsave(&rb->event_lock, flags);
5346 list_add_rcu(&event->rb_entry, &rb->event_list);
5347 spin_unlock_irqrestore(&rb->event_lock, flags);
5351 * Avoid racing with perf_mmap_close(AUX): stop the event
5352 * before swizzling the event::rb pointer; if it's getting
5353 * unmapped, its aux_mmap_count will be 0 and it won't
5354 * restart. See the comment in __perf_pmu_output_stop().
5356 * Data will inevitably be lost when set_output is done in
5357 * mid-air, but then again, whoever does it like this is
5358 * not in for the data anyway.
5361 perf_event_stop(event, 0);
5363 rcu_assign_pointer(event->rb, rb);
5366 ring_buffer_put(old_rb);
5368 * Since we detached before setting the new rb, so that we
5369 * could attach the new rb, we could have missed a wakeup.
5372 wake_up_all(&event->waitq);
5376 static void ring_buffer_wakeup(struct perf_event *event)
5378 struct ring_buffer *rb;
5381 rb = rcu_dereference(event->rb);
5383 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5384 wake_up_all(&event->waitq);
5389 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5391 struct ring_buffer *rb;
5394 rb = rcu_dereference(event->rb);
5396 if (!refcount_inc_not_zero(&rb->refcount))
5404 void ring_buffer_put(struct ring_buffer *rb)
5406 if (!refcount_dec_and_test(&rb->refcount))
5409 WARN_ON_ONCE(!list_empty(&rb->event_list));
5411 call_rcu(&rb->rcu_head, rb_free_rcu);
5414 static void perf_mmap_open(struct vm_area_struct *vma)
5416 struct perf_event *event = vma->vm_file->private_data;
5418 atomic_inc(&event->mmap_count);
5419 atomic_inc(&event->rb->mmap_count);
5422 atomic_inc(&event->rb->aux_mmap_count);
5424 if (event->pmu->event_mapped)
5425 event->pmu->event_mapped(event, vma->vm_mm);
5428 static void perf_pmu_output_stop(struct perf_event *event);
5431 * A buffer can be mmap()ed multiple times; either directly through the same
5432 * event, or through other events by use of perf_event_set_output().
5434 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5435 * the buffer here, where we still have a VM context. This means we need
5436 * to detach all events redirecting to us.
5438 static void perf_mmap_close(struct vm_area_struct *vma)
5440 struct perf_event *event = vma->vm_file->private_data;
5442 struct ring_buffer *rb = ring_buffer_get(event);
5443 struct user_struct *mmap_user = rb->mmap_user;
5444 int mmap_locked = rb->mmap_locked;
5445 unsigned long size = perf_data_size(rb);
5447 if (event->pmu->event_unmapped)
5448 event->pmu->event_unmapped(event, vma->vm_mm);
5451 * rb->aux_mmap_count will always drop before rb->mmap_count and
5452 * event->mmap_count, so it is ok to use event->mmap_mutex to
5453 * serialize with perf_mmap here.
5455 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5456 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5458 * Stop all AUX events that are writing to this buffer,
5459 * so that we can free its AUX pages and corresponding PMU
5460 * data. Note that after rb::aux_mmap_count dropped to zero,
5461 * they won't start any more (see perf_aux_output_begin()).
5463 perf_pmu_output_stop(event);
5465 /* now it's safe to free the pages */
5466 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5467 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5469 /* this has to be the last one */
5471 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5473 mutex_unlock(&event->mmap_mutex);
5476 atomic_dec(&rb->mmap_count);
5478 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5481 ring_buffer_attach(event, NULL);
5482 mutex_unlock(&event->mmap_mutex);
5484 /* If there's still other mmap()s of this buffer, we're done. */
5485 if (atomic_read(&rb->mmap_count))
5489 * No other mmap()s, detach from all other events that might redirect
5490 * into the now unreachable buffer. Somewhat complicated by the
5491 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5495 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5496 if (!atomic_long_inc_not_zero(&event->refcount)) {
5498 * This event is en-route to free_event() which will
5499 * detach it and remove it from the list.
5505 mutex_lock(&event->mmap_mutex);
5507 * Check we didn't race with perf_event_set_output() which can
5508 * swizzle the rb from under us while we were waiting to
5509 * acquire mmap_mutex.
5511 * If we find a different rb; ignore this event, a next
5512 * iteration will no longer find it on the list. We have to
5513 * still restart the iteration to make sure we're not now
5514 * iterating the wrong list.
5516 if (event->rb == rb)
5517 ring_buffer_attach(event, NULL);
5519 mutex_unlock(&event->mmap_mutex);
5523 * Restart the iteration; either we're on the wrong list or
5524 * destroyed its integrity by doing a deletion.
5531 * It could be there's still a few 0-ref events on the list; they'll
5532 * get cleaned up by free_event() -- they'll also still have their
5533 * ref on the rb and will free it whenever they are done with it.
5535 * Aside from that, this buffer is 'fully' detached and unmapped,
5536 * undo the VM accounting.
5539 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5540 vma->vm_mm->pinned_vm -= mmap_locked;
5541 free_uid(mmap_user);
5544 ring_buffer_put(rb); /* could be last */
5547 static const struct vm_operations_struct perf_mmap_vmops = {
5548 .open = perf_mmap_open,
5549 .close = perf_mmap_close, /* non mergeable */
5550 .fault = perf_mmap_fault,
5551 .page_mkwrite = perf_mmap_fault,
5554 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5556 struct perf_event *event = file->private_data;
5557 unsigned long user_locked, user_lock_limit;
5558 struct user_struct *user = current_user();
5559 unsigned long locked, lock_limit;
5560 struct ring_buffer *rb = NULL;
5561 unsigned long vma_size;
5562 unsigned long nr_pages;
5563 long user_extra = 0, extra = 0;
5564 int ret = 0, flags = 0;
5567 * Don't allow mmap() of inherited per-task counters. This would
5568 * create a performance issue due to all children writing to the
5571 if (event->cpu == -1 && event->attr.inherit)
5574 if (!(vma->vm_flags & VM_SHARED))
5577 vma_size = vma->vm_end - vma->vm_start;
5579 if (vma->vm_pgoff == 0) {
5580 nr_pages = (vma_size / PAGE_SIZE) - 1;
5583 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5584 * mapped, all subsequent mappings should have the same size
5585 * and offset. Must be above the normal perf buffer.
5587 u64 aux_offset, aux_size;
5592 nr_pages = vma_size / PAGE_SIZE;
5594 mutex_lock(&event->mmap_mutex);
5601 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5602 aux_size = READ_ONCE(rb->user_page->aux_size);
5604 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5607 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5610 /* already mapped with a different offset */
5611 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5614 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5617 /* already mapped with a different size */
5618 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5621 if (!is_power_of_2(nr_pages))
5624 if (!atomic_inc_not_zero(&rb->mmap_count))
5627 if (rb_has_aux(rb)) {
5628 atomic_inc(&rb->aux_mmap_count);
5633 atomic_set(&rb->aux_mmap_count, 1);
5634 user_extra = nr_pages;
5640 * If we have rb pages ensure they're a power-of-two number, so we
5641 * can do bitmasks instead of modulo.
5643 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5646 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5649 WARN_ON_ONCE(event->ctx->parent_ctx);
5651 mutex_lock(&event->mmap_mutex);
5653 if (event->rb->nr_pages != nr_pages) {
5658 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5660 * Raced against perf_mmap_close() through
5661 * perf_event_set_output(). Try again, hope for better
5664 mutex_unlock(&event->mmap_mutex);
5671 user_extra = nr_pages + 1;
5674 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5677 * Increase the limit linearly with more CPUs:
5679 user_lock_limit *= num_online_cpus();
5681 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5683 if (user_locked > user_lock_limit)
5684 extra = user_locked - user_lock_limit;
5686 lock_limit = rlimit(RLIMIT_MEMLOCK);
5687 lock_limit >>= PAGE_SHIFT;
5688 locked = vma->vm_mm->pinned_vm + extra;
5690 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5691 !capable(CAP_IPC_LOCK)) {
5696 WARN_ON(!rb && event->rb);
5698 if (vma->vm_flags & VM_WRITE)
5699 flags |= RING_BUFFER_WRITABLE;
5702 rb = rb_alloc(nr_pages,
5703 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5711 atomic_set(&rb->mmap_count, 1);
5712 rb->mmap_user = get_current_user();
5713 rb->mmap_locked = extra;
5715 ring_buffer_attach(event, rb);
5717 perf_event_init_userpage(event);
5718 perf_event_update_userpage(event);
5720 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5721 event->attr.aux_watermark, flags);
5723 rb->aux_mmap_locked = extra;
5728 atomic_long_add(user_extra, &user->locked_vm);
5729 vma->vm_mm->pinned_vm += extra;
5731 atomic_inc(&event->mmap_count);
5733 atomic_dec(&rb->mmap_count);
5736 mutex_unlock(&event->mmap_mutex);
5739 * Since pinned accounting is per vm we cannot allow fork() to copy our
5742 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5743 vma->vm_ops = &perf_mmap_vmops;
5745 if (event->pmu->event_mapped)
5746 event->pmu->event_mapped(event, vma->vm_mm);
5751 static int perf_fasync(int fd, struct file *filp, int on)
5753 struct inode *inode = file_inode(filp);
5754 struct perf_event *event = filp->private_data;
5758 retval = fasync_helper(fd, filp, on, &event->fasync);
5759 inode_unlock(inode);
5767 static const struct file_operations perf_fops = {
5768 .llseek = no_llseek,
5769 .release = perf_release,
5772 .unlocked_ioctl = perf_ioctl,
5773 .compat_ioctl = perf_compat_ioctl,
5775 .fasync = perf_fasync,
5781 * If there's data, ensure we set the poll() state and publish everything
5782 * to user-space before waking everybody up.
5785 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5787 /* only the parent has fasync state */
5789 event = event->parent;
5790 return &event->fasync;
5793 void perf_event_wakeup(struct perf_event *event)
5795 ring_buffer_wakeup(event);
5797 if (event->pending_kill) {
5798 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5799 event->pending_kill = 0;
5803 static void perf_pending_event(struct irq_work *entry)
5805 struct perf_event *event = container_of(entry,
5806 struct perf_event, pending);
5809 rctx = perf_swevent_get_recursion_context();
5811 * If we 'fail' here, that's OK, it means recursion is already disabled
5812 * and we won't recurse 'further'.
5815 if (event->pending_disable) {
5816 event->pending_disable = 0;
5817 perf_event_disable_local(event);
5820 if (event->pending_wakeup) {
5821 event->pending_wakeup = 0;
5822 perf_event_wakeup(event);
5826 perf_swevent_put_recursion_context(rctx);
5830 * We assume there is only KVM supporting the callbacks.
5831 * Later on, we might change it to a list if there is
5832 * another virtualization implementation supporting the callbacks.
5834 struct perf_guest_info_callbacks *perf_guest_cbs;
5836 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5838 perf_guest_cbs = cbs;
5841 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5843 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5845 perf_guest_cbs = NULL;
5848 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5851 perf_output_sample_regs(struct perf_output_handle *handle,
5852 struct pt_regs *regs, u64 mask)
5855 DECLARE_BITMAP(_mask, 64);
5857 bitmap_from_u64(_mask, mask);
5858 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5861 val = perf_reg_value(regs, bit);
5862 perf_output_put(handle, val);
5866 static void perf_sample_regs_user(struct perf_regs *regs_user,
5867 struct pt_regs *regs,
5868 struct pt_regs *regs_user_copy)
5870 if (user_mode(regs)) {
5871 regs_user->abi = perf_reg_abi(current);
5872 regs_user->regs = regs;
5873 } else if (current->mm) {
5874 perf_get_regs_user(regs_user, regs, regs_user_copy);
5876 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5877 regs_user->regs = NULL;
5881 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5882 struct pt_regs *regs)
5884 regs_intr->regs = regs;
5885 regs_intr->abi = perf_reg_abi(current);
5890 * Get remaining task size from user stack pointer.
5892 * It'd be better to take stack vma map and limit this more
5893 * precisly, but there's no way to get it safely under interrupt,
5894 * so using TASK_SIZE as limit.
5896 static u64 perf_ustack_task_size(struct pt_regs *regs)
5898 unsigned long addr = perf_user_stack_pointer(regs);
5900 if (!addr || addr >= TASK_SIZE)
5903 return TASK_SIZE - addr;
5907 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5908 struct pt_regs *regs)
5912 /* No regs, no stack pointer, no dump. */
5917 * Check if we fit in with the requested stack size into the:
5919 * If we don't, we limit the size to the TASK_SIZE.
5921 * - remaining sample size
5922 * If we don't, we customize the stack size to
5923 * fit in to the remaining sample size.
5926 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5927 stack_size = min(stack_size, (u16) task_size);
5929 /* Current header size plus static size and dynamic size. */
5930 header_size += 2 * sizeof(u64);
5932 /* Do we fit in with the current stack dump size? */
5933 if ((u16) (header_size + stack_size) < header_size) {
5935 * If we overflow the maximum size for the sample,
5936 * we customize the stack dump size to fit in.
5938 stack_size = USHRT_MAX - header_size - sizeof(u64);
5939 stack_size = round_up(stack_size, sizeof(u64));
5946 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5947 struct pt_regs *regs)
5949 /* Case of a kernel thread, nothing to dump */
5952 perf_output_put(handle, size);
5962 * - the size requested by user or the best one we can fit
5963 * in to the sample max size
5965 * - user stack dump data
5967 * - the actual dumped size
5971 perf_output_put(handle, dump_size);
5974 sp = perf_user_stack_pointer(regs);
5977 rem = __output_copy_user(handle, (void *) sp, dump_size);
5979 dyn_size = dump_size - rem;
5981 perf_output_skip(handle, rem);
5984 perf_output_put(handle, dyn_size);
5988 static void __perf_event_header__init_id(struct perf_event_header *header,
5989 struct perf_sample_data *data,
5990 struct perf_event *event)
5992 u64 sample_type = event->attr.sample_type;
5994 data->type = sample_type;
5995 header->size += event->id_header_size;
5997 if (sample_type & PERF_SAMPLE_TID) {
5998 /* namespace issues */
5999 data->tid_entry.pid = perf_event_pid(event, current);
6000 data->tid_entry.tid = perf_event_tid(event, current);
6003 if (sample_type & PERF_SAMPLE_TIME)
6004 data->time = perf_event_clock(event);
6006 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6007 data->id = primary_event_id(event);
6009 if (sample_type & PERF_SAMPLE_STREAM_ID)
6010 data->stream_id = event->id;
6012 if (sample_type & PERF_SAMPLE_CPU) {
6013 data->cpu_entry.cpu = raw_smp_processor_id();
6014 data->cpu_entry.reserved = 0;
6018 void perf_event_header__init_id(struct perf_event_header *header,
6019 struct perf_sample_data *data,
6020 struct perf_event *event)
6022 if (event->attr.sample_id_all)
6023 __perf_event_header__init_id(header, data, event);
6026 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6027 struct perf_sample_data *data)
6029 u64 sample_type = data->type;
6031 if (sample_type & PERF_SAMPLE_TID)
6032 perf_output_put(handle, data->tid_entry);
6034 if (sample_type & PERF_SAMPLE_TIME)
6035 perf_output_put(handle, data->time);
6037 if (sample_type & PERF_SAMPLE_ID)
6038 perf_output_put(handle, data->id);
6040 if (sample_type & PERF_SAMPLE_STREAM_ID)
6041 perf_output_put(handle, data->stream_id);
6043 if (sample_type & PERF_SAMPLE_CPU)
6044 perf_output_put(handle, data->cpu_entry);
6046 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6047 perf_output_put(handle, data->id);
6050 void perf_event__output_id_sample(struct perf_event *event,
6051 struct perf_output_handle *handle,
6052 struct perf_sample_data *sample)
6054 if (event->attr.sample_id_all)
6055 __perf_event__output_id_sample(handle, sample);
6058 static void perf_output_read_one(struct perf_output_handle *handle,
6059 struct perf_event *event,
6060 u64 enabled, u64 running)
6062 u64 read_format = event->attr.read_format;
6066 values[n++] = perf_event_count(event);
6067 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6068 values[n++] = enabled +
6069 atomic64_read(&event->child_total_time_enabled);
6071 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6072 values[n++] = running +
6073 atomic64_read(&event->child_total_time_running);
6075 if (read_format & PERF_FORMAT_ID)
6076 values[n++] = primary_event_id(event);
6078 __output_copy(handle, values, n * sizeof(u64));
6081 static void perf_output_read_group(struct perf_output_handle *handle,
6082 struct perf_event *event,
6083 u64 enabled, u64 running)
6085 struct perf_event *leader = event->group_leader, *sub;
6086 u64 read_format = event->attr.read_format;
6090 values[n++] = 1 + leader->nr_siblings;
6092 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6093 values[n++] = enabled;
6095 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6096 values[n++] = running;
6098 if ((leader != event) &&
6099 (leader->state == PERF_EVENT_STATE_ACTIVE))
6100 leader->pmu->read(leader);
6102 values[n++] = perf_event_count(leader);
6103 if (read_format & PERF_FORMAT_ID)
6104 values[n++] = primary_event_id(leader);
6106 __output_copy(handle, values, n * sizeof(u64));
6108 for_each_sibling_event(sub, leader) {
6111 if ((sub != event) &&
6112 (sub->state == PERF_EVENT_STATE_ACTIVE))
6113 sub->pmu->read(sub);
6115 values[n++] = perf_event_count(sub);
6116 if (read_format & PERF_FORMAT_ID)
6117 values[n++] = primary_event_id(sub);
6119 __output_copy(handle, values, n * sizeof(u64));
6123 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6124 PERF_FORMAT_TOTAL_TIME_RUNNING)
6127 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6129 * The problem is that its both hard and excessively expensive to iterate the
6130 * child list, not to mention that its impossible to IPI the children running
6131 * on another CPU, from interrupt/NMI context.
6133 static void perf_output_read(struct perf_output_handle *handle,
6134 struct perf_event *event)
6136 u64 enabled = 0, running = 0, now;
6137 u64 read_format = event->attr.read_format;
6140 * compute total_time_enabled, total_time_running
6141 * based on snapshot values taken when the event
6142 * was last scheduled in.
6144 * we cannot simply called update_context_time()
6145 * because of locking issue as we are called in
6148 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6149 calc_timer_values(event, &now, &enabled, &running);
6151 if (event->attr.read_format & PERF_FORMAT_GROUP)
6152 perf_output_read_group(handle, event, enabled, running);
6154 perf_output_read_one(handle, event, enabled, running);
6157 void perf_output_sample(struct perf_output_handle *handle,
6158 struct perf_event_header *header,
6159 struct perf_sample_data *data,
6160 struct perf_event *event)
6162 u64 sample_type = data->type;
6164 perf_output_put(handle, *header);
6166 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6167 perf_output_put(handle, data->id);
6169 if (sample_type & PERF_SAMPLE_IP)
6170 perf_output_put(handle, data->ip);
6172 if (sample_type & PERF_SAMPLE_TID)
6173 perf_output_put(handle, data->tid_entry);
6175 if (sample_type & PERF_SAMPLE_TIME)
6176 perf_output_put(handle, data->time);
6178 if (sample_type & PERF_SAMPLE_ADDR)
6179 perf_output_put(handle, data->addr);
6181 if (sample_type & PERF_SAMPLE_ID)
6182 perf_output_put(handle, data->id);
6184 if (sample_type & PERF_SAMPLE_STREAM_ID)
6185 perf_output_put(handle, data->stream_id);
6187 if (sample_type & PERF_SAMPLE_CPU)
6188 perf_output_put(handle, data->cpu_entry);
6190 if (sample_type & PERF_SAMPLE_PERIOD)
6191 perf_output_put(handle, data->period);
6193 if (sample_type & PERF_SAMPLE_READ)
6194 perf_output_read(handle, event);
6196 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6199 size += data->callchain->nr;
6200 size *= sizeof(u64);
6201 __output_copy(handle, data->callchain, size);
6204 if (sample_type & PERF_SAMPLE_RAW) {
6205 struct perf_raw_record *raw = data->raw;
6208 struct perf_raw_frag *frag = &raw->frag;
6210 perf_output_put(handle, raw->size);
6213 __output_custom(handle, frag->copy,
6214 frag->data, frag->size);
6216 __output_copy(handle, frag->data,
6219 if (perf_raw_frag_last(frag))
6224 __output_skip(handle, NULL, frag->pad);
6230 .size = sizeof(u32),
6233 perf_output_put(handle, raw);
6237 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6238 if (data->br_stack) {
6241 size = data->br_stack->nr
6242 * sizeof(struct perf_branch_entry);
6244 perf_output_put(handle, data->br_stack->nr);
6245 perf_output_copy(handle, data->br_stack->entries, size);
6248 * we always store at least the value of nr
6251 perf_output_put(handle, nr);
6255 if (sample_type & PERF_SAMPLE_REGS_USER) {
6256 u64 abi = data->regs_user.abi;
6259 * If there are no regs to dump, notice it through
6260 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6262 perf_output_put(handle, abi);
6265 u64 mask = event->attr.sample_regs_user;
6266 perf_output_sample_regs(handle,
6267 data->regs_user.regs,
6272 if (sample_type & PERF_SAMPLE_STACK_USER) {
6273 perf_output_sample_ustack(handle,
6274 data->stack_user_size,
6275 data->regs_user.regs);
6278 if (sample_type & PERF_SAMPLE_WEIGHT)
6279 perf_output_put(handle, data->weight);
6281 if (sample_type & PERF_SAMPLE_DATA_SRC)
6282 perf_output_put(handle, data->data_src.val);
6284 if (sample_type & PERF_SAMPLE_TRANSACTION)
6285 perf_output_put(handle, data->txn);
6287 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6288 u64 abi = data->regs_intr.abi;
6290 * If there are no regs to dump, notice it through
6291 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6293 perf_output_put(handle, abi);
6296 u64 mask = event->attr.sample_regs_intr;
6298 perf_output_sample_regs(handle,
6299 data->regs_intr.regs,
6304 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6305 perf_output_put(handle, data->phys_addr);
6307 if (!event->attr.watermark) {
6308 int wakeup_events = event->attr.wakeup_events;
6310 if (wakeup_events) {
6311 struct ring_buffer *rb = handle->rb;
6312 int events = local_inc_return(&rb->events);
6314 if (events >= wakeup_events) {
6315 local_sub(wakeup_events, &rb->events);
6316 local_inc(&rb->wakeup);
6322 static u64 perf_virt_to_phys(u64 virt)
6325 struct page *p = NULL;
6330 if (virt >= TASK_SIZE) {
6331 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6332 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6333 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6334 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6337 * Walking the pages tables for user address.
6338 * Interrupts are disabled, so it prevents any tear down
6339 * of the page tables.
6340 * Try IRQ-safe __get_user_pages_fast first.
6341 * If failed, leave phys_addr as 0.
6343 if ((current->mm != NULL) &&
6344 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6345 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6354 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6356 struct perf_callchain_entry *
6357 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6359 bool kernel = !event->attr.exclude_callchain_kernel;
6360 bool user = !event->attr.exclude_callchain_user;
6361 /* Disallow cross-task user callchains. */
6362 bool crosstask = event->ctx->task && event->ctx->task != current;
6363 const u32 max_stack = event->attr.sample_max_stack;
6364 struct perf_callchain_entry *callchain;
6366 if (!kernel && !user)
6367 return &__empty_callchain;
6369 callchain = get_perf_callchain(regs, 0, kernel, user,
6370 max_stack, crosstask, true);
6371 return callchain ?: &__empty_callchain;
6374 void perf_prepare_sample(struct perf_event_header *header,
6375 struct perf_sample_data *data,
6376 struct perf_event *event,
6377 struct pt_regs *regs)
6379 u64 sample_type = event->attr.sample_type;
6381 header->type = PERF_RECORD_SAMPLE;
6382 header->size = sizeof(*header) + event->header_size;
6385 header->misc |= perf_misc_flags(regs);
6387 __perf_event_header__init_id(header, data, event);
6389 if (sample_type & PERF_SAMPLE_IP)
6390 data->ip = perf_instruction_pointer(regs);
6392 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6395 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6396 data->callchain = perf_callchain(event, regs);
6398 size += data->callchain->nr;
6400 header->size += size * sizeof(u64);
6403 if (sample_type & PERF_SAMPLE_RAW) {
6404 struct perf_raw_record *raw = data->raw;
6408 struct perf_raw_frag *frag = &raw->frag;
6413 if (perf_raw_frag_last(frag))
6418 size = round_up(sum + sizeof(u32), sizeof(u64));
6419 raw->size = size - sizeof(u32);
6420 frag->pad = raw->size - sum;
6425 header->size += size;
6428 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6429 int size = sizeof(u64); /* nr */
6430 if (data->br_stack) {
6431 size += data->br_stack->nr
6432 * sizeof(struct perf_branch_entry);
6434 header->size += size;
6437 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6438 perf_sample_regs_user(&data->regs_user, regs,
6439 &data->regs_user_copy);
6441 if (sample_type & PERF_SAMPLE_REGS_USER) {
6442 /* regs dump ABI info */
6443 int size = sizeof(u64);
6445 if (data->regs_user.regs) {
6446 u64 mask = event->attr.sample_regs_user;
6447 size += hweight64(mask) * sizeof(u64);
6450 header->size += size;
6453 if (sample_type & PERF_SAMPLE_STACK_USER) {
6455 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6456 * processed as the last one or have additional check added
6457 * in case new sample type is added, because we could eat
6458 * up the rest of the sample size.
6460 u16 stack_size = event->attr.sample_stack_user;
6461 u16 size = sizeof(u64);
6463 stack_size = perf_sample_ustack_size(stack_size, header->size,
6464 data->regs_user.regs);
6467 * If there is something to dump, add space for the dump
6468 * itself and for the field that tells the dynamic size,
6469 * which is how many have been actually dumped.
6472 size += sizeof(u64) + stack_size;
6474 data->stack_user_size = stack_size;
6475 header->size += size;
6478 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6479 /* regs dump ABI info */
6480 int size = sizeof(u64);
6482 perf_sample_regs_intr(&data->regs_intr, regs);
6484 if (data->regs_intr.regs) {
6485 u64 mask = event->attr.sample_regs_intr;
6487 size += hweight64(mask) * sizeof(u64);
6490 header->size += size;
6493 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6494 data->phys_addr = perf_virt_to_phys(data->addr);
6497 static __always_inline int
6498 __perf_event_output(struct perf_event *event,
6499 struct perf_sample_data *data,
6500 struct pt_regs *regs,
6501 int (*output_begin)(struct perf_output_handle *,
6502 struct perf_event *,
6505 struct perf_output_handle handle;
6506 struct perf_event_header header;
6509 /* protect the callchain buffers */
6512 perf_prepare_sample(&header, data, event, regs);
6514 err = output_begin(&handle, event, header.size);
6518 perf_output_sample(&handle, &header, data, event);
6520 perf_output_end(&handle);
6528 perf_event_output_forward(struct perf_event *event,
6529 struct perf_sample_data *data,
6530 struct pt_regs *regs)
6532 __perf_event_output(event, data, regs, perf_output_begin_forward);
6536 perf_event_output_backward(struct perf_event *event,
6537 struct perf_sample_data *data,
6538 struct pt_regs *regs)
6540 __perf_event_output(event, data, regs, perf_output_begin_backward);
6544 perf_event_output(struct perf_event *event,
6545 struct perf_sample_data *data,
6546 struct pt_regs *regs)
6548 return __perf_event_output(event, data, regs, perf_output_begin);
6555 struct perf_read_event {
6556 struct perf_event_header header;
6563 perf_event_read_event(struct perf_event *event,
6564 struct task_struct *task)
6566 struct perf_output_handle handle;
6567 struct perf_sample_data sample;
6568 struct perf_read_event read_event = {
6570 .type = PERF_RECORD_READ,
6572 .size = sizeof(read_event) + event->read_size,
6574 .pid = perf_event_pid(event, task),
6575 .tid = perf_event_tid(event, task),
6579 perf_event_header__init_id(&read_event.header, &sample, event);
6580 ret = perf_output_begin(&handle, event, read_event.header.size);
6584 perf_output_put(&handle, read_event);
6585 perf_output_read(&handle, event);
6586 perf_event__output_id_sample(event, &handle, &sample);
6588 perf_output_end(&handle);
6591 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6594 perf_iterate_ctx(struct perf_event_context *ctx,
6595 perf_iterate_f output,
6596 void *data, bool all)
6598 struct perf_event *event;
6600 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6602 if (event->state < PERF_EVENT_STATE_INACTIVE)
6604 if (!event_filter_match(event))
6608 output(event, data);
6612 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6614 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6615 struct perf_event *event;
6617 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6619 * Skip events that are not fully formed yet; ensure that
6620 * if we observe event->ctx, both event and ctx will be
6621 * complete enough. See perf_install_in_context().
6623 if (!smp_load_acquire(&event->ctx))
6626 if (event->state < PERF_EVENT_STATE_INACTIVE)
6628 if (!event_filter_match(event))
6630 output(event, data);
6635 * Iterate all events that need to receive side-band events.
6637 * For new callers; ensure that account_pmu_sb_event() includes
6638 * your event, otherwise it might not get delivered.
6641 perf_iterate_sb(perf_iterate_f output, void *data,
6642 struct perf_event_context *task_ctx)
6644 struct perf_event_context *ctx;
6651 * If we have task_ctx != NULL we only notify the task context itself.
6652 * The task_ctx is set only for EXIT events before releasing task
6656 perf_iterate_ctx(task_ctx, output, data, false);
6660 perf_iterate_sb_cpu(output, data);
6662 for_each_task_context_nr(ctxn) {
6663 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6665 perf_iterate_ctx(ctx, output, data, false);
6673 * Clear all file-based filters at exec, they'll have to be
6674 * re-instated when/if these objects are mmapped again.
6676 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6678 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6679 struct perf_addr_filter *filter;
6680 unsigned int restart = 0, count = 0;
6681 unsigned long flags;
6683 if (!has_addr_filter(event))
6686 raw_spin_lock_irqsave(&ifh->lock, flags);
6687 list_for_each_entry(filter, &ifh->list, entry) {
6688 if (filter->path.dentry) {
6689 event->addr_filters_offs[count] = 0;
6697 event->addr_filters_gen++;
6698 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6701 perf_event_stop(event, 1);
6704 void perf_event_exec(void)
6706 struct perf_event_context *ctx;
6710 for_each_task_context_nr(ctxn) {
6711 ctx = current->perf_event_ctxp[ctxn];
6715 perf_event_enable_on_exec(ctxn);
6717 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6723 struct remote_output {
6724 struct ring_buffer *rb;
6728 static void __perf_event_output_stop(struct perf_event *event, void *data)
6730 struct perf_event *parent = event->parent;
6731 struct remote_output *ro = data;
6732 struct ring_buffer *rb = ro->rb;
6733 struct stop_event_data sd = {
6737 if (!has_aux(event))
6744 * In case of inheritance, it will be the parent that links to the
6745 * ring-buffer, but it will be the child that's actually using it.
6747 * We are using event::rb to determine if the event should be stopped,
6748 * however this may race with ring_buffer_attach() (through set_output),
6749 * which will make us skip the event that actually needs to be stopped.
6750 * So ring_buffer_attach() has to stop an aux event before re-assigning
6753 if (rcu_dereference(parent->rb) == rb)
6754 ro->err = __perf_event_stop(&sd);
6757 static int __perf_pmu_output_stop(void *info)
6759 struct perf_event *event = info;
6760 struct pmu *pmu = event->pmu;
6761 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6762 struct remote_output ro = {
6767 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6768 if (cpuctx->task_ctx)
6769 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6776 static void perf_pmu_output_stop(struct perf_event *event)
6778 struct perf_event *iter;
6783 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6785 * For per-CPU events, we need to make sure that neither they
6786 * nor their children are running; for cpu==-1 events it's
6787 * sufficient to stop the event itself if it's active, since
6788 * it can't have children.
6792 cpu = READ_ONCE(iter->oncpu);
6797 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6798 if (err == -EAGAIN) {
6807 * task tracking -- fork/exit
6809 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6812 struct perf_task_event {
6813 struct task_struct *task;
6814 struct perf_event_context *task_ctx;
6817 struct perf_event_header header;
6827 static int perf_event_task_match(struct perf_event *event)
6829 return event->attr.comm || event->attr.mmap ||
6830 event->attr.mmap2 || event->attr.mmap_data ||
6834 static void perf_event_task_output(struct perf_event *event,
6837 struct perf_task_event *task_event = data;
6838 struct perf_output_handle handle;
6839 struct perf_sample_data sample;
6840 struct task_struct *task = task_event->task;
6841 int ret, size = task_event->event_id.header.size;
6843 if (!perf_event_task_match(event))
6846 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6848 ret = perf_output_begin(&handle, event,
6849 task_event->event_id.header.size);
6853 task_event->event_id.pid = perf_event_pid(event, task);
6854 task_event->event_id.ppid = perf_event_pid(event, current);
6856 task_event->event_id.tid = perf_event_tid(event, task);
6857 task_event->event_id.ptid = perf_event_tid(event, current);
6859 task_event->event_id.time = perf_event_clock(event);
6861 perf_output_put(&handle, task_event->event_id);
6863 perf_event__output_id_sample(event, &handle, &sample);
6865 perf_output_end(&handle);
6867 task_event->event_id.header.size = size;
6870 static void perf_event_task(struct task_struct *task,
6871 struct perf_event_context *task_ctx,
6874 struct perf_task_event task_event;
6876 if (!atomic_read(&nr_comm_events) &&
6877 !atomic_read(&nr_mmap_events) &&
6878 !atomic_read(&nr_task_events))
6881 task_event = (struct perf_task_event){
6883 .task_ctx = task_ctx,
6886 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6888 .size = sizeof(task_event.event_id),
6898 perf_iterate_sb(perf_event_task_output,
6903 void perf_event_fork(struct task_struct *task)
6905 perf_event_task(task, NULL, 1);
6906 perf_event_namespaces(task);
6913 struct perf_comm_event {
6914 struct task_struct *task;
6919 struct perf_event_header header;
6926 static int perf_event_comm_match(struct perf_event *event)
6928 return event->attr.comm;
6931 static void perf_event_comm_output(struct perf_event *event,
6934 struct perf_comm_event *comm_event = data;
6935 struct perf_output_handle handle;
6936 struct perf_sample_data sample;
6937 int size = comm_event->event_id.header.size;
6940 if (!perf_event_comm_match(event))
6943 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6944 ret = perf_output_begin(&handle, event,
6945 comm_event->event_id.header.size);
6950 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6951 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6953 perf_output_put(&handle, comm_event->event_id);
6954 __output_copy(&handle, comm_event->comm,
6955 comm_event->comm_size);
6957 perf_event__output_id_sample(event, &handle, &sample);
6959 perf_output_end(&handle);
6961 comm_event->event_id.header.size = size;
6964 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6966 char comm[TASK_COMM_LEN];
6969 memset(comm, 0, sizeof(comm));
6970 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6971 size = ALIGN(strlen(comm)+1, sizeof(u64));
6973 comm_event->comm = comm;
6974 comm_event->comm_size = size;
6976 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6978 perf_iterate_sb(perf_event_comm_output,
6983 void perf_event_comm(struct task_struct *task, bool exec)
6985 struct perf_comm_event comm_event;
6987 if (!atomic_read(&nr_comm_events))
6990 comm_event = (struct perf_comm_event){
6996 .type = PERF_RECORD_COMM,
6997 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7005 perf_event_comm_event(&comm_event);
7009 * namespaces tracking
7012 struct perf_namespaces_event {
7013 struct task_struct *task;
7016 struct perf_event_header header;
7021 struct perf_ns_link_info link_info[NR_NAMESPACES];
7025 static int perf_event_namespaces_match(struct perf_event *event)
7027 return event->attr.namespaces;
7030 static void perf_event_namespaces_output(struct perf_event *event,
7033 struct perf_namespaces_event *namespaces_event = data;
7034 struct perf_output_handle handle;
7035 struct perf_sample_data sample;
7036 u16 header_size = namespaces_event->event_id.header.size;
7039 if (!perf_event_namespaces_match(event))
7042 perf_event_header__init_id(&namespaces_event->event_id.header,
7044 ret = perf_output_begin(&handle, event,
7045 namespaces_event->event_id.header.size);
7049 namespaces_event->event_id.pid = perf_event_pid(event,
7050 namespaces_event->task);
7051 namespaces_event->event_id.tid = perf_event_tid(event,
7052 namespaces_event->task);
7054 perf_output_put(&handle, namespaces_event->event_id);
7056 perf_event__output_id_sample(event, &handle, &sample);
7058 perf_output_end(&handle);
7060 namespaces_event->event_id.header.size = header_size;
7063 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7064 struct task_struct *task,
7065 const struct proc_ns_operations *ns_ops)
7067 struct path ns_path;
7068 struct inode *ns_inode;
7071 error = ns_get_path(&ns_path, task, ns_ops);
7073 ns_inode = ns_path.dentry->d_inode;
7074 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7075 ns_link_info->ino = ns_inode->i_ino;
7080 void perf_event_namespaces(struct task_struct *task)
7082 struct perf_namespaces_event namespaces_event;
7083 struct perf_ns_link_info *ns_link_info;
7085 if (!atomic_read(&nr_namespaces_events))
7088 namespaces_event = (struct perf_namespaces_event){
7092 .type = PERF_RECORD_NAMESPACES,
7094 .size = sizeof(namespaces_event.event_id),
7098 .nr_namespaces = NR_NAMESPACES,
7099 /* .link_info[NR_NAMESPACES] */
7103 ns_link_info = namespaces_event.event_id.link_info;
7105 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7106 task, &mntns_operations);
7108 #ifdef CONFIG_USER_NS
7109 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7110 task, &userns_operations);
7112 #ifdef CONFIG_NET_NS
7113 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7114 task, &netns_operations);
7116 #ifdef CONFIG_UTS_NS
7117 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7118 task, &utsns_operations);
7120 #ifdef CONFIG_IPC_NS
7121 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7122 task, &ipcns_operations);
7124 #ifdef CONFIG_PID_NS
7125 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7126 task, &pidns_operations);
7128 #ifdef CONFIG_CGROUPS
7129 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7130 task, &cgroupns_operations);
7133 perf_iterate_sb(perf_event_namespaces_output,
7142 struct perf_mmap_event {
7143 struct vm_area_struct *vma;
7145 const char *file_name;
7153 struct perf_event_header header;
7163 static int perf_event_mmap_match(struct perf_event *event,
7166 struct perf_mmap_event *mmap_event = data;
7167 struct vm_area_struct *vma = mmap_event->vma;
7168 int executable = vma->vm_flags & VM_EXEC;
7170 return (!executable && event->attr.mmap_data) ||
7171 (executable && (event->attr.mmap || event->attr.mmap2));
7174 static void perf_event_mmap_output(struct perf_event *event,
7177 struct perf_mmap_event *mmap_event = data;
7178 struct perf_output_handle handle;
7179 struct perf_sample_data sample;
7180 int size = mmap_event->event_id.header.size;
7183 if (!perf_event_mmap_match(event, data))
7186 if (event->attr.mmap2) {
7187 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7188 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7189 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7190 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7191 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7192 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7193 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7196 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7197 ret = perf_output_begin(&handle, event,
7198 mmap_event->event_id.header.size);
7202 mmap_event->event_id.pid = perf_event_pid(event, current);
7203 mmap_event->event_id.tid = perf_event_tid(event, current);
7205 perf_output_put(&handle, mmap_event->event_id);
7207 if (event->attr.mmap2) {
7208 perf_output_put(&handle, mmap_event->maj);
7209 perf_output_put(&handle, mmap_event->min);
7210 perf_output_put(&handle, mmap_event->ino);
7211 perf_output_put(&handle, mmap_event->ino_generation);
7212 perf_output_put(&handle, mmap_event->prot);
7213 perf_output_put(&handle, mmap_event->flags);
7216 __output_copy(&handle, mmap_event->file_name,
7217 mmap_event->file_size);
7219 perf_event__output_id_sample(event, &handle, &sample);
7221 perf_output_end(&handle);
7223 mmap_event->event_id.header.size = size;
7226 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7228 struct vm_area_struct *vma = mmap_event->vma;
7229 struct file *file = vma->vm_file;
7230 int maj = 0, min = 0;
7231 u64 ino = 0, gen = 0;
7232 u32 prot = 0, flags = 0;
7238 if (vma->vm_flags & VM_READ)
7240 if (vma->vm_flags & VM_WRITE)
7242 if (vma->vm_flags & VM_EXEC)
7245 if (vma->vm_flags & VM_MAYSHARE)
7248 flags = MAP_PRIVATE;
7250 if (vma->vm_flags & VM_DENYWRITE)
7251 flags |= MAP_DENYWRITE;
7252 if (vma->vm_flags & VM_MAYEXEC)
7253 flags |= MAP_EXECUTABLE;
7254 if (vma->vm_flags & VM_LOCKED)
7255 flags |= MAP_LOCKED;
7256 if (vma->vm_flags & VM_HUGETLB)
7257 flags |= MAP_HUGETLB;
7260 struct inode *inode;
7263 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7269 * d_path() works from the end of the rb backwards, so we
7270 * need to add enough zero bytes after the string to handle
7271 * the 64bit alignment we do later.
7273 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7278 inode = file_inode(vma->vm_file);
7279 dev = inode->i_sb->s_dev;
7281 gen = inode->i_generation;
7287 if (vma->vm_ops && vma->vm_ops->name) {
7288 name = (char *) vma->vm_ops->name(vma);
7293 name = (char *)arch_vma_name(vma);
7297 if (vma->vm_start <= vma->vm_mm->start_brk &&
7298 vma->vm_end >= vma->vm_mm->brk) {
7302 if (vma->vm_start <= vma->vm_mm->start_stack &&
7303 vma->vm_end >= vma->vm_mm->start_stack) {
7313 strlcpy(tmp, name, sizeof(tmp));
7317 * Since our buffer works in 8 byte units we need to align our string
7318 * size to a multiple of 8. However, we must guarantee the tail end is
7319 * zero'd out to avoid leaking random bits to userspace.
7321 size = strlen(name)+1;
7322 while (!IS_ALIGNED(size, sizeof(u64)))
7323 name[size++] = '\0';
7325 mmap_event->file_name = name;
7326 mmap_event->file_size = size;
7327 mmap_event->maj = maj;
7328 mmap_event->min = min;
7329 mmap_event->ino = ino;
7330 mmap_event->ino_generation = gen;
7331 mmap_event->prot = prot;
7332 mmap_event->flags = flags;
7334 if (!(vma->vm_flags & VM_EXEC))
7335 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7337 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7339 perf_iterate_sb(perf_event_mmap_output,
7347 * Check whether inode and address range match filter criteria.
7349 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7350 struct file *file, unsigned long offset,
7353 /* d_inode(NULL) won't be equal to any mapped user-space file */
7354 if (!filter->path.dentry)
7357 if (d_inode(filter->path.dentry) != file_inode(file))
7360 if (filter->offset > offset + size)
7363 if (filter->offset + filter->size < offset)
7369 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7371 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7372 struct vm_area_struct *vma = data;
7373 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7374 struct file *file = vma->vm_file;
7375 struct perf_addr_filter *filter;
7376 unsigned int restart = 0, count = 0;
7378 if (!has_addr_filter(event))
7384 raw_spin_lock_irqsave(&ifh->lock, flags);
7385 list_for_each_entry(filter, &ifh->list, entry) {
7386 if (perf_addr_filter_match(filter, file, off,
7387 vma->vm_end - vma->vm_start)) {
7388 event->addr_filters_offs[count] = vma->vm_start;
7396 event->addr_filters_gen++;
7397 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7400 perf_event_stop(event, 1);
7404 * Adjust all task's events' filters to the new vma
7406 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7408 struct perf_event_context *ctx;
7412 * Data tracing isn't supported yet and as such there is no need
7413 * to keep track of anything that isn't related to executable code:
7415 if (!(vma->vm_flags & VM_EXEC))
7419 for_each_task_context_nr(ctxn) {
7420 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7424 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7429 void perf_event_mmap(struct vm_area_struct *vma)
7431 struct perf_mmap_event mmap_event;
7433 if (!atomic_read(&nr_mmap_events))
7436 mmap_event = (struct perf_mmap_event){
7442 .type = PERF_RECORD_MMAP,
7443 .misc = PERF_RECORD_MISC_USER,
7448 .start = vma->vm_start,
7449 .len = vma->vm_end - vma->vm_start,
7450 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7452 /* .maj (attr_mmap2 only) */
7453 /* .min (attr_mmap2 only) */
7454 /* .ino (attr_mmap2 only) */
7455 /* .ino_generation (attr_mmap2 only) */
7456 /* .prot (attr_mmap2 only) */
7457 /* .flags (attr_mmap2 only) */
7460 perf_addr_filters_adjust(vma);
7461 perf_event_mmap_event(&mmap_event);
7464 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7465 unsigned long size, u64 flags)
7467 struct perf_output_handle handle;
7468 struct perf_sample_data sample;
7469 struct perf_aux_event {
7470 struct perf_event_header header;
7476 .type = PERF_RECORD_AUX,
7478 .size = sizeof(rec),
7486 perf_event_header__init_id(&rec.header, &sample, event);
7487 ret = perf_output_begin(&handle, event, rec.header.size);
7492 perf_output_put(&handle, rec);
7493 perf_event__output_id_sample(event, &handle, &sample);
7495 perf_output_end(&handle);
7499 * Lost/dropped samples logging
7501 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7503 struct perf_output_handle handle;
7504 struct perf_sample_data sample;
7508 struct perf_event_header header;
7510 } lost_samples_event = {
7512 .type = PERF_RECORD_LOST_SAMPLES,
7514 .size = sizeof(lost_samples_event),
7519 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7521 ret = perf_output_begin(&handle, event,
7522 lost_samples_event.header.size);
7526 perf_output_put(&handle, lost_samples_event);
7527 perf_event__output_id_sample(event, &handle, &sample);
7528 perf_output_end(&handle);
7532 * context_switch tracking
7535 struct perf_switch_event {
7536 struct task_struct *task;
7537 struct task_struct *next_prev;
7540 struct perf_event_header header;
7546 static int perf_event_switch_match(struct perf_event *event)
7548 return event->attr.context_switch;
7551 static void perf_event_switch_output(struct perf_event *event, void *data)
7553 struct perf_switch_event *se = data;
7554 struct perf_output_handle handle;
7555 struct perf_sample_data sample;
7558 if (!perf_event_switch_match(event))
7561 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7562 if (event->ctx->task) {
7563 se->event_id.header.type = PERF_RECORD_SWITCH;
7564 se->event_id.header.size = sizeof(se->event_id.header);
7566 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7567 se->event_id.header.size = sizeof(se->event_id);
7568 se->event_id.next_prev_pid =
7569 perf_event_pid(event, se->next_prev);
7570 se->event_id.next_prev_tid =
7571 perf_event_tid(event, se->next_prev);
7574 perf_event_header__init_id(&se->event_id.header, &sample, event);
7576 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7580 if (event->ctx->task)
7581 perf_output_put(&handle, se->event_id.header);
7583 perf_output_put(&handle, se->event_id);
7585 perf_event__output_id_sample(event, &handle, &sample);
7587 perf_output_end(&handle);
7590 static void perf_event_switch(struct task_struct *task,
7591 struct task_struct *next_prev, bool sched_in)
7593 struct perf_switch_event switch_event;
7595 /* N.B. caller checks nr_switch_events != 0 */
7597 switch_event = (struct perf_switch_event){
7599 .next_prev = next_prev,
7603 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7606 /* .next_prev_pid */
7607 /* .next_prev_tid */
7611 if (!sched_in && task->state == TASK_RUNNING)
7612 switch_event.event_id.header.misc |=
7613 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7615 perf_iterate_sb(perf_event_switch_output,
7621 * IRQ throttle logging
7624 static void perf_log_throttle(struct perf_event *event, int enable)
7626 struct perf_output_handle handle;
7627 struct perf_sample_data sample;
7631 struct perf_event_header header;
7635 } throttle_event = {
7637 .type = PERF_RECORD_THROTTLE,
7639 .size = sizeof(throttle_event),
7641 .time = perf_event_clock(event),
7642 .id = primary_event_id(event),
7643 .stream_id = event->id,
7647 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7649 perf_event_header__init_id(&throttle_event.header, &sample, event);
7651 ret = perf_output_begin(&handle, event,
7652 throttle_event.header.size);
7656 perf_output_put(&handle, throttle_event);
7657 perf_event__output_id_sample(event, &handle, &sample);
7658 perf_output_end(&handle);
7662 * ksymbol register/unregister tracking
7665 struct perf_ksymbol_event {
7669 struct perf_event_header header;
7677 static int perf_event_ksymbol_match(struct perf_event *event)
7679 return event->attr.ksymbol;
7682 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7684 struct perf_ksymbol_event *ksymbol_event = data;
7685 struct perf_output_handle handle;
7686 struct perf_sample_data sample;
7689 if (!perf_event_ksymbol_match(event))
7692 perf_event_header__init_id(&ksymbol_event->event_id.header,
7694 ret = perf_output_begin(&handle, event,
7695 ksymbol_event->event_id.header.size);
7699 perf_output_put(&handle, ksymbol_event->event_id);
7700 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7701 perf_event__output_id_sample(event, &handle, &sample);
7703 perf_output_end(&handle);
7706 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7709 struct perf_ksymbol_event ksymbol_event;
7710 char name[KSYM_NAME_LEN];
7714 if (!atomic_read(&nr_ksymbol_events))
7717 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7718 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7721 strlcpy(name, sym, KSYM_NAME_LEN);
7722 name_len = strlen(name) + 1;
7723 while (!IS_ALIGNED(name_len, sizeof(u64)))
7724 name[name_len++] = '\0';
7725 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7728 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7730 ksymbol_event = (struct perf_ksymbol_event){
7732 .name_len = name_len,
7735 .type = PERF_RECORD_KSYMBOL,
7736 .size = sizeof(ksymbol_event.event_id) +
7741 .ksym_type = ksym_type,
7746 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7749 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7753 * bpf program load/unload tracking
7756 struct perf_bpf_event {
7757 struct bpf_prog *prog;
7759 struct perf_event_header header;
7763 u8 tag[BPF_TAG_SIZE];
7767 static int perf_event_bpf_match(struct perf_event *event)
7769 return event->attr.bpf_event;
7772 static void perf_event_bpf_output(struct perf_event *event, void *data)
7774 struct perf_bpf_event *bpf_event = data;
7775 struct perf_output_handle handle;
7776 struct perf_sample_data sample;
7779 if (!perf_event_bpf_match(event))
7782 perf_event_header__init_id(&bpf_event->event_id.header,
7784 ret = perf_output_begin(&handle, event,
7785 bpf_event->event_id.header.size);
7789 perf_output_put(&handle, bpf_event->event_id);
7790 perf_event__output_id_sample(event, &handle, &sample);
7792 perf_output_end(&handle);
7795 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
7796 enum perf_bpf_event_type type)
7798 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
7799 char sym[KSYM_NAME_LEN];
7802 if (prog->aux->func_cnt == 0) {
7803 bpf_get_prog_name(prog, sym);
7804 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
7805 (u64)(unsigned long)prog->bpf_func,
7806 prog->jited_len, unregister, sym);
7808 for (i = 0; i < prog->aux->func_cnt; i++) {
7809 struct bpf_prog *subprog = prog->aux->func[i];
7811 bpf_get_prog_name(subprog, sym);
7813 PERF_RECORD_KSYMBOL_TYPE_BPF,
7814 (u64)(unsigned long)subprog->bpf_func,
7815 subprog->jited_len, unregister, sym);
7820 void perf_event_bpf_event(struct bpf_prog *prog,
7821 enum perf_bpf_event_type type,
7824 struct perf_bpf_event bpf_event;
7826 if (type <= PERF_BPF_EVENT_UNKNOWN ||
7827 type >= PERF_BPF_EVENT_MAX)
7831 case PERF_BPF_EVENT_PROG_LOAD:
7832 case PERF_BPF_EVENT_PROG_UNLOAD:
7833 if (atomic_read(&nr_ksymbol_events))
7834 perf_event_bpf_emit_ksymbols(prog, type);
7840 if (!atomic_read(&nr_bpf_events))
7843 bpf_event = (struct perf_bpf_event){
7847 .type = PERF_RECORD_BPF_EVENT,
7848 .size = sizeof(bpf_event.event_id),
7852 .id = prog->aux->id,
7856 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
7858 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
7859 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
7862 void perf_event_itrace_started(struct perf_event *event)
7864 event->attach_state |= PERF_ATTACH_ITRACE;
7867 static void perf_log_itrace_start(struct perf_event *event)
7869 struct perf_output_handle handle;
7870 struct perf_sample_data sample;
7871 struct perf_aux_event {
7872 struct perf_event_header header;
7879 event = event->parent;
7881 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7882 event->attach_state & PERF_ATTACH_ITRACE)
7885 rec.header.type = PERF_RECORD_ITRACE_START;
7886 rec.header.misc = 0;
7887 rec.header.size = sizeof(rec);
7888 rec.pid = perf_event_pid(event, current);
7889 rec.tid = perf_event_tid(event, current);
7891 perf_event_header__init_id(&rec.header, &sample, event);
7892 ret = perf_output_begin(&handle, event, rec.header.size);
7897 perf_output_put(&handle, rec);
7898 perf_event__output_id_sample(event, &handle, &sample);
7900 perf_output_end(&handle);
7904 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7906 struct hw_perf_event *hwc = &event->hw;
7910 seq = __this_cpu_read(perf_throttled_seq);
7911 if (seq != hwc->interrupts_seq) {
7912 hwc->interrupts_seq = seq;
7913 hwc->interrupts = 1;
7916 if (unlikely(throttle
7917 && hwc->interrupts >= max_samples_per_tick)) {
7918 __this_cpu_inc(perf_throttled_count);
7919 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7920 hwc->interrupts = MAX_INTERRUPTS;
7921 perf_log_throttle(event, 0);
7926 if (event->attr.freq) {
7927 u64 now = perf_clock();
7928 s64 delta = now - hwc->freq_time_stamp;
7930 hwc->freq_time_stamp = now;
7932 if (delta > 0 && delta < 2*TICK_NSEC)
7933 perf_adjust_period(event, delta, hwc->last_period, true);
7939 int perf_event_account_interrupt(struct perf_event *event)
7941 return __perf_event_account_interrupt(event, 1);
7945 * Generic event overflow handling, sampling.
7948 static int __perf_event_overflow(struct perf_event *event,
7949 int throttle, struct perf_sample_data *data,
7950 struct pt_regs *regs)
7952 int events = atomic_read(&event->event_limit);
7956 * Non-sampling counters might still use the PMI to fold short
7957 * hardware counters, ignore those.
7959 if (unlikely(!is_sampling_event(event)))
7962 ret = __perf_event_account_interrupt(event, throttle);
7965 * XXX event_limit might not quite work as expected on inherited
7969 event->pending_kill = POLL_IN;
7970 if (events && atomic_dec_and_test(&event->event_limit)) {
7972 event->pending_kill = POLL_HUP;
7974 perf_event_disable_inatomic(event);
7977 READ_ONCE(event->overflow_handler)(event, data, regs);
7979 if (*perf_event_fasync(event) && event->pending_kill) {
7980 event->pending_wakeup = 1;
7981 irq_work_queue(&event->pending);
7987 int perf_event_overflow(struct perf_event *event,
7988 struct perf_sample_data *data,
7989 struct pt_regs *regs)
7991 return __perf_event_overflow(event, 1, data, regs);
7995 * Generic software event infrastructure
7998 struct swevent_htable {
7999 struct swevent_hlist *swevent_hlist;
8000 struct mutex hlist_mutex;
8003 /* Recursion avoidance in each contexts */
8004 int recursion[PERF_NR_CONTEXTS];
8007 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8010 * We directly increment event->count and keep a second value in
8011 * event->hw.period_left to count intervals. This period event
8012 * is kept in the range [-sample_period, 0] so that we can use the
8016 u64 perf_swevent_set_period(struct perf_event *event)
8018 struct hw_perf_event *hwc = &event->hw;
8019 u64 period = hwc->last_period;
8023 hwc->last_period = hwc->sample_period;
8026 old = val = local64_read(&hwc->period_left);
8030 nr = div64_u64(period + val, period);
8031 offset = nr * period;
8033 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8039 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8040 struct perf_sample_data *data,
8041 struct pt_regs *regs)
8043 struct hw_perf_event *hwc = &event->hw;
8047 overflow = perf_swevent_set_period(event);
8049 if (hwc->interrupts == MAX_INTERRUPTS)
8052 for (; overflow; overflow--) {
8053 if (__perf_event_overflow(event, throttle,
8056 * We inhibit the overflow from happening when
8057 * hwc->interrupts == MAX_INTERRUPTS.
8065 static void perf_swevent_event(struct perf_event *event, u64 nr,
8066 struct perf_sample_data *data,
8067 struct pt_regs *regs)
8069 struct hw_perf_event *hwc = &event->hw;
8071 local64_add(nr, &event->count);
8076 if (!is_sampling_event(event))
8079 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8081 return perf_swevent_overflow(event, 1, data, regs);
8083 data->period = event->hw.last_period;
8085 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8086 return perf_swevent_overflow(event, 1, data, regs);
8088 if (local64_add_negative(nr, &hwc->period_left))
8091 perf_swevent_overflow(event, 0, data, regs);
8094 static int perf_exclude_event(struct perf_event *event,
8095 struct pt_regs *regs)
8097 if (event->hw.state & PERF_HES_STOPPED)
8101 if (event->attr.exclude_user && user_mode(regs))
8104 if (event->attr.exclude_kernel && !user_mode(regs))
8111 static int perf_swevent_match(struct perf_event *event,
8112 enum perf_type_id type,
8114 struct perf_sample_data *data,
8115 struct pt_regs *regs)
8117 if (event->attr.type != type)
8120 if (event->attr.config != event_id)
8123 if (perf_exclude_event(event, regs))
8129 static inline u64 swevent_hash(u64 type, u32 event_id)
8131 u64 val = event_id | (type << 32);
8133 return hash_64(val, SWEVENT_HLIST_BITS);
8136 static inline struct hlist_head *
8137 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8139 u64 hash = swevent_hash(type, event_id);
8141 return &hlist->heads[hash];
8144 /* For the read side: events when they trigger */
8145 static inline struct hlist_head *
8146 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8148 struct swevent_hlist *hlist;
8150 hlist = rcu_dereference(swhash->swevent_hlist);
8154 return __find_swevent_head(hlist, type, event_id);
8157 /* For the event head insertion and removal in the hlist */
8158 static inline struct hlist_head *
8159 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8161 struct swevent_hlist *hlist;
8162 u32 event_id = event->attr.config;
8163 u64 type = event->attr.type;
8166 * Event scheduling is always serialized against hlist allocation
8167 * and release. Which makes the protected version suitable here.
8168 * The context lock guarantees that.
8170 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8171 lockdep_is_held(&event->ctx->lock));
8175 return __find_swevent_head(hlist, type, event_id);
8178 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8180 struct perf_sample_data *data,
8181 struct pt_regs *regs)
8183 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8184 struct perf_event *event;
8185 struct hlist_head *head;
8188 head = find_swevent_head_rcu(swhash, type, event_id);
8192 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8193 if (perf_swevent_match(event, type, event_id, data, regs))
8194 perf_swevent_event(event, nr, data, regs);
8200 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8202 int perf_swevent_get_recursion_context(void)
8204 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8206 return get_recursion_context(swhash->recursion);
8208 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8210 void perf_swevent_put_recursion_context(int rctx)
8212 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8214 put_recursion_context(swhash->recursion, rctx);
8217 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8219 struct perf_sample_data data;
8221 if (WARN_ON_ONCE(!regs))
8224 perf_sample_data_init(&data, addr, 0);
8225 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8228 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8232 preempt_disable_notrace();
8233 rctx = perf_swevent_get_recursion_context();
8234 if (unlikely(rctx < 0))
8237 ___perf_sw_event(event_id, nr, regs, addr);
8239 perf_swevent_put_recursion_context(rctx);
8241 preempt_enable_notrace();
8244 static void perf_swevent_read(struct perf_event *event)
8248 static int perf_swevent_add(struct perf_event *event, int flags)
8250 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8251 struct hw_perf_event *hwc = &event->hw;
8252 struct hlist_head *head;
8254 if (is_sampling_event(event)) {
8255 hwc->last_period = hwc->sample_period;
8256 perf_swevent_set_period(event);
8259 hwc->state = !(flags & PERF_EF_START);
8261 head = find_swevent_head(swhash, event);
8262 if (WARN_ON_ONCE(!head))
8265 hlist_add_head_rcu(&event->hlist_entry, head);
8266 perf_event_update_userpage(event);
8271 static void perf_swevent_del(struct perf_event *event, int flags)
8273 hlist_del_rcu(&event->hlist_entry);
8276 static void perf_swevent_start(struct perf_event *event, int flags)
8278 event->hw.state = 0;
8281 static void perf_swevent_stop(struct perf_event *event, int flags)
8283 event->hw.state = PERF_HES_STOPPED;
8286 /* Deref the hlist from the update side */
8287 static inline struct swevent_hlist *
8288 swevent_hlist_deref(struct swevent_htable *swhash)
8290 return rcu_dereference_protected(swhash->swevent_hlist,
8291 lockdep_is_held(&swhash->hlist_mutex));
8294 static void swevent_hlist_release(struct swevent_htable *swhash)
8296 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8301 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8302 kfree_rcu(hlist, rcu_head);
8305 static void swevent_hlist_put_cpu(int cpu)
8307 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8309 mutex_lock(&swhash->hlist_mutex);
8311 if (!--swhash->hlist_refcount)
8312 swevent_hlist_release(swhash);
8314 mutex_unlock(&swhash->hlist_mutex);
8317 static void swevent_hlist_put(void)
8321 for_each_possible_cpu(cpu)
8322 swevent_hlist_put_cpu(cpu);
8325 static int swevent_hlist_get_cpu(int cpu)
8327 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8330 mutex_lock(&swhash->hlist_mutex);
8331 if (!swevent_hlist_deref(swhash) &&
8332 cpumask_test_cpu(cpu, perf_online_mask)) {
8333 struct swevent_hlist *hlist;
8335 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8340 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8342 swhash->hlist_refcount++;
8344 mutex_unlock(&swhash->hlist_mutex);
8349 static int swevent_hlist_get(void)
8351 int err, cpu, failed_cpu;
8353 mutex_lock(&pmus_lock);
8354 for_each_possible_cpu(cpu) {
8355 err = swevent_hlist_get_cpu(cpu);
8361 mutex_unlock(&pmus_lock);
8364 for_each_possible_cpu(cpu) {
8365 if (cpu == failed_cpu)
8367 swevent_hlist_put_cpu(cpu);
8369 mutex_unlock(&pmus_lock);
8373 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8375 static void sw_perf_event_destroy(struct perf_event *event)
8377 u64 event_id = event->attr.config;
8379 WARN_ON(event->parent);
8381 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8382 swevent_hlist_put();
8385 static int perf_swevent_init(struct perf_event *event)
8387 u64 event_id = event->attr.config;
8389 if (event->attr.type != PERF_TYPE_SOFTWARE)
8393 * no branch sampling for software events
8395 if (has_branch_stack(event))
8399 case PERF_COUNT_SW_CPU_CLOCK:
8400 case PERF_COUNT_SW_TASK_CLOCK:
8407 if (event_id >= PERF_COUNT_SW_MAX)
8410 if (!event->parent) {
8413 err = swevent_hlist_get();
8417 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8418 event->destroy = sw_perf_event_destroy;
8424 static struct pmu perf_swevent = {
8425 .task_ctx_nr = perf_sw_context,
8427 .capabilities = PERF_PMU_CAP_NO_NMI,
8429 .event_init = perf_swevent_init,
8430 .add = perf_swevent_add,
8431 .del = perf_swevent_del,
8432 .start = perf_swevent_start,
8433 .stop = perf_swevent_stop,
8434 .read = perf_swevent_read,
8437 #ifdef CONFIG_EVENT_TRACING
8439 static int perf_tp_filter_match(struct perf_event *event,
8440 struct perf_sample_data *data)
8442 void *record = data->raw->frag.data;
8444 /* only top level events have filters set */
8446 event = event->parent;
8448 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8453 static int perf_tp_event_match(struct perf_event *event,
8454 struct perf_sample_data *data,
8455 struct pt_regs *regs)
8457 if (event->hw.state & PERF_HES_STOPPED)
8460 * All tracepoints are from kernel-space.
8462 if (event->attr.exclude_kernel)
8465 if (!perf_tp_filter_match(event, data))
8471 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8472 struct trace_event_call *call, u64 count,
8473 struct pt_regs *regs, struct hlist_head *head,
8474 struct task_struct *task)
8476 if (bpf_prog_array_valid(call)) {
8477 *(struct pt_regs **)raw_data = regs;
8478 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8479 perf_swevent_put_recursion_context(rctx);
8483 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8486 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8488 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8489 struct pt_regs *regs, struct hlist_head *head, int rctx,
8490 struct task_struct *task)
8492 struct perf_sample_data data;
8493 struct perf_event *event;
8495 struct perf_raw_record raw = {
8502 perf_sample_data_init(&data, 0, 0);
8505 perf_trace_buf_update(record, event_type);
8507 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8508 if (perf_tp_event_match(event, &data, regs))
8509 perf_swevent_event(event, count, &data, regs);
8513 * If we got specified a target task, also iterate its context and
8514 * deliver this event there too.
8516 if (task && task != current) {
8517 struct perf_event_context *ctx;
8518 struct trace_entry *entry = record;
8521 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8525 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8526 if (event->cpu != smp_processor_id())
8528 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8530 if (event->attr.config != entry->type)
8532 if (perf_tp_event_match(event, &data, regs))
8533 perf_swevent_event(event, count, &data, regs);
8539 perf_swevent_put_recursion_context(rctx);
8541 EXPORT_SYMBOL_GPL(perf_tp_event);
8543 static void tp_perf_event_destroy(struct perf_event *event)
8545 perf_trace_destroy(event);
8548 static int perf_tp_event_init(struct perf_event *event)
8552 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8556 * no branch sampling for tracepoint events
8558 if (has_branch_stack(event))
8561 err = perf_trace_init(event);
8565 event->destroy = tp_perf_event_destroy;
8570 static struct pmu perf_tracepoint = {
8571 .task_ctx_nr = perf_sw_context,
8573 .event_init = perf_tp_event_init,
8574 .add = perf_trace_add,
8575 .del = perf_trace_del,
8576 .start = perf_swevent_start,
8577 .stop = perf_swevent_stop,
8578 .read = perf_swevent_read,
8581 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8583 * Flags in config, used by dynamic PMU kprobe and uprobe
8584 * The flags should match following PMU_FORMAT_ATTR().
8586 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8587 * if not set, create kprobe/uprobe
8589 * The following values specify a reference counter (or semaphore in the
8590 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8591 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8593 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8594 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8596 enum perf_probe_config {
8597 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8598 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8599 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8602 PMU_FORMAT_ATTR(retprobe, "config:0");
8605 #ifdef CONFIG_KPROBE_EVENTS
8606 static struct attribute *kprobe_attrs[] = {
8607 &format_attr_retprobe.attr,
8611 static struct attribute_group kprobe_format_group = {
8613 .attrs = kprobe_attrs,
8616 static const struct attribute_group *kprobe_attr_groups[] = {
8617 &kprobe_format_group,
8621 static int perf_kprobe_event_init(struct perf_event *event);
8622 static struct pmu perf_kprobe = {
8623 .task_ctx_nr = perf_sw_context,
8624 .event_init = perf_kprobe_event_init,
8625 .add = perf_trace_add,
8626 .del = perf_trace_del,
8627 .start = perf_swevent_start,
8628 .stop = perf_swevent_stop,
8629 .read = perf_swevent_read,
8630 .attr_groups = kprobe_attr_groups,
8633 static int perf_kprobe_event_init(struct perf_event *event)
8638 if (event->attr.type != perf_kprobe.type)
8641 if (!capable(CAP_SYS_ADMIN))
8645 * no branch sampling for probe events
8647 if (has_branch_stack(event))
8650 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8651 err = perf_kprobe_init(event, is_retprobe);
8655 event->destroy = perf_kprobe_destroy;
8659 #endif /* CONFIG_KPROBE_EVENTS */
8661 #ifdef CONFIG_UPROBE_EVENTS
8662 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8664 static struct attribute *uprobe_attrs[] = {
8665 &format_attr_retprobe.attr,
8666 &format_attr_ref_ctr_offset.attr,
8670 static struct attribute_group uprobe_format_group = {
8672 .attrs = uprobe_attrs,
8675 static const struct attribute_group *uprobe_attr_groups[] = {
8676 &uprobe_format_group,
8680 static int perf_uprobe_event_init(struct perf_event *event);
8681 static struct pmu perf_uprobe = {
8682 .task_ctx_nr = perf_sw_context,
8683 .event_init = perf_uprobe_event_init,
8684 .add = perf_trace_add,
8685 .del = perf_trace_del,
8686 .start = perf_swevent_start,
8687 .stop = perf_swevent_stop,
8688 .read = perf_swevent_read,
8689 .attr_groups = uprobe_attr_groups,
8692 static int perf_uprobe_event_init(struct perf_event *event)
8695 unsigned long ref_ctr_offset;
8698 if (event->attr.type != perf_uprobe.type)
8701 if (!capable(CAP_SYS_ADMIN))
8705 * no branch sampling for probe events
8707 if (has_branch_stack(event))
8710 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8711 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8712 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8716 event->destroy = perf_uprobe_destroy;
8720 #endif /* CONFIG_UPROBE_EVENTS */
8722 static inline void perf_tp_register(void)
8724 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8725 #ifdef CONFIG_KPROBE_EVENTS
8726 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8728 #ifdef CONFIG_UPROBE_EVENTS
8729 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8733 static void perf_event_free_filter(struct perf_event *event)
8735 ftrace_profile_free_filter(event);
8738 #ifdef CONFIG_BPF_SYSCALL
8739 static void bpf_overflow_handler(struct perf_event *event,
8740 struct perf_sample_data *data,
8741 struct pt_regs *regs)
8743 struct bpf_perf_event_data_kern ctx = {
8749 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8751 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8754 ret = BPF_PROG_RUN(event->prog, &ctx);
8757 __this_cpu_dec(bpf_prog_active);
8762 event->orig_overflow_handler(event, data, regs);
8765 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8767 struct bpf_prog *prog;
8769 if (event->overflow_handler_context)
8770 /* hw breakpoint or kernel counter */
8776 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8778 return PTR_ERR(prog);
8781 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8782 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8786 static void perf_event_free_bpf_handler(struct perf_event *event)
8788 struct bpf_prog *prog = event->prog;
8793 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8798 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8802 static void perf_event_free_bpf_handler(struct perf_event *event)
8808 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8809 * with perf_event_open()
8811 static inline bool perf_event_is_tracing(struct perf_event *event)
8813 if (event->pmu == &perf_tracepoint)
8815 #ifdef CONFIG_KPROBE_EVENTS
8816 if (event->pmu == &perf_kprobe)
8819 #ifdef CONFIG_UPROBE_EVENTS
8820 if (event->pmu == &perf_uprobe)
8826 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8828 bool is_kprobe, is_tracepoint, is_syscall_tp;
8829 struct bpf_prog *prog;
8832 if (!perf_event_is_tracing(event))
8833 return perf_event_set_bpf_handler(event, prog_fd);
8835 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8836 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8837 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8838 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8839 /* bpf programs can only be attached to u/kprobe or tracepoint */
8842 prog = bpf_prog_get(prog_fd);
8844 return PTR_ERR(prog);
8846 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8847 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8848 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8849 /* valid fd, but invalid bpf program type */
8854 /* Kprobe override only works for kprobes, not uprobes. */
8855 if (prog->kprobe_override &&
8856 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8861 if (is_tracepoint || is_syscall_tp) {
8862 int off = trace_event_get_offsets(event->tp_event);
8864 if (prog->aux->max_ctx_offset > off) {
8870 ret = perf_event_attach_bpf_prog(event, prog);
8876 static void perf_event_free_bpf_prog(struct perf_event *event)
8878 if (!perf_event_is_tracing(event)) {
8879 perf_event_free_bpf_handler(event);
8882 perf_event_detach_bpf_prog(event);
8887 static inline void perf_tp_register(void)
8891 static void perf_event_free_filter(struct perf_event *event)
8895 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8900 static void perf_event_free_bpf_prog(struct perf_event *event)
8903 #endif /* CONFIG_EVENT_TRACING */
8905 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8906 void perf_bp_event(struct perf_event *bp, void *data)
8908 struct perf_sample_data sample;
8909 struct pt_regs *regs = data;
8911 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8913 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8914 perf_swevent_event(bp, 1, &sample, regs);
8919 * Allocate a new address filter
8921 static struct perf_addr_filter *
8922 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8924 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8925 struct perf_addr_filter *filter;
8927 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8931 INIT_LIST_HEAD(&filter->entry);
8932 list_add_tail(&filter->entry, filters);
8937 static void free_filters_list(struct list_head *filters)
8939 struct perf_addr_filter *filter, *iter;
8941 list_for_each_entry_safe(filter, iter, filters, entry) {
8942 path_put(&filter->path);
8943 list_del(&filter->entry);
8949 * Free existing address filters and optionally install new ones
8951 static void perf_addr_filters_splice(struct perf_event *event,
8952 struct list_head *head)
8954 unsigned long flags;
8957 if (!has_addr_filter(event))
8960 /* don't bother with children, they don't have their own filters */
8964 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8966 list_splice_init(&event->addr_filters.list, &list);
8968 list_splice(head, &event->addr_filters.list);
8970 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8972 free_filters_list(&list);
8976 * Scan through mm's vmas and see if one of them matches the
8977 * @filter; if so, adjust filter's address range.
8978 * Called with mm::mmap_sem down for reading.
8980 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8981 struct mm_struct *mm)
8983 struct vm_area_struct *vma;
8985 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8986 struct file *file = vma->vm_file;
8987 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8988 unsigned long vma_size = vma->vm_end - vma->vm_start;
8993 if (!perf_addr_filter_match(filter, file, off, vma_size))
8996 return vma->vm_start;
9003 * Update event's address range filters based on the
9004 * task's existing mappings, if any.
9006 static void perf_event_addr_filters_apply(struct perf_event *event)
9008 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9009 struct task_struct *task = READ_ONCE(event->ctx->task);
9010 struct perf_addr_filter *filter;
9011 struct mm_struct *mm = NULL;
9012 unsigned int count = 0;
9013 unsigned long flags;
9016 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9017 * will stop on the parent's child_mutex that our caller is also holding
9019 if (task == TASK_TOMBSTONE)
9022 if (!ifh->nr_file_filters)
9025 mm = get_task_mm(event->ctx->task);
9029 down_read(&mm->mmap_sem);
9031 raw_spin_lock_irqsave(&ifh->lock, flags);
9032 list_for_each_entry(filter, &ifh->list, entry) {
9033 event->addr_filters_offs[count] = 0;
9036 * Adjust base offset if the filter is associated to a binary
9037 * that needs to be mapped:
9039 if (filter->path.dentry)
9040 event->addr_filters_offs[count] =
9041 perf_addr_filter_apply(filter, mm);
9046 event->addr_filters_gen++;
9047 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9049 up_read(&mm->mmap_sem);
9054 perf_event_stop(event, 1);
9058 * Address range filtering: limiting the data to certain
9059 * instruction address ranges. Filters are ioctl()ed to us from
9060 * userspace as ascii strings.
9062 * Filter string format:
9065 * where ACTION is one of the
9066 * * "filter": limit the trace to this region
9067 * * "start": start tracing from this address
9068 * * "stop": stop tracing at this address/region;
9070 * * for kernel addresses: <start address>[/<size>]
9071 * * for object files: <start address>[/<size>]@</path/to/object/file>
9073 * if <size> is not specified or is zero, the range is treated as a single
9074 * address; not valid for ACTION=="filter".
9088 IF_STATE_ACTION = 0,
9093 static const match_table_t if_tokens = {
9094 { IF_ACT_FILTER, "filter" },
9095 { IF_ACT_START, "start" },
9096 { IF_ACT_STOP, "stop" },
9097 { IF_SRC_FILE, "%u/%u@%s" },
9098 { IF_SRC_KERNEL, "%u/%u" },
9099 { IF_SRC_FILEADDR, "%u@%s" },
9100 { IF_SRC_KERNELADDR, "%u" },
9101 { IF_ACT_NONE, NULL },
9105 * Address filter string parser
9108 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9109 struct list_head *filters)
9111 struct perf_addr_filter *filter = NULL;
9112 char *start, *orig, *filename = NULL;
9113 substring_t args[MAX_OPT_ARGS];
9114 int state = IF_STATE_ACTION, token;
9115 unsigned int kernel = 0;
9118 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9122 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9123 static const enum perf_addr_filter_action_t actions[] = {
9124 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9125 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9126 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9133 /* filter definition begins */
9134 if (state == IF_STATE_ACTION) {
9135 filter = perf_addr_filter_new(event, filters);
9140 token = match_token(start, if_tokens, args);
9145 if (state != IF_STATE_ACTION)
9148 filter->action = actions[token];
9149 state = IF_STATE_SOURCE;
9152 case IF_SRC_KERNELADDR:
9156 case IF_SRC_FILEADDR:
9158 if (state != IF_STATE_SOURCE)
9162 ret = kstrtoul(args[0].from, 0, &filter->offset);
9166 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9168 ret = kstrtoul(args[1].from, 0, &filter->size);
9173 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9174 int fpos = token == IF_SRC_FILE ? 2 : 1;
9176 filename = match_strdup(&args[fpos]);
9183 state = IF_STATE_END;
9191 * Filter definition is fully parsed, validate and install it.
9192 * Make sure that it doesn't contradict itself or the event's
9195 if (state == IF_STATE_END) {
9197 if (kernel && event->attr.exclude_kernel)
9201 * ACTION "filter" must have a non-zero length region
9204 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9213 * For now, we only support file-based filters
9214 * in per-task events; doing so for CPU-wide
9215 * events requires additional context switching
9216 * trickery, since same object code will be
9217 * mapped at different virtual addresses in
9218 * different processes.
9221 if (!event->ctx->task)
9222 goto fail_free_name;
9224 /* look up the path and grab its inode */
9225 ret = kern_path(filename, LOOKUP_FOLLOW,
9228 goto fail_free_name;
9234 if (!filter->path.dentry ||
9235 !S_ISREG(d_inode(filter->path.dentry)
9239 event->addr_filters.nr_file_filters++;
9242 /* ready to consume more filters */
9243 state = IF_STATE_ACTION;
9248 if (state != IF_STATE_ACTION)
9258 free_filters_list(filters);
9265 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9271 * Since this is called in perf_ioctl() path, we're already holding
9274 lockdep_assert_held(&event->ctx->mutex);
9276 if (WARN_ON_ONCE(event->parent))
9279 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9281 goto fail_clear_files;
9283 ret = event->pmu->addr_filters_validate(&filters);
9285 goto fail_free_filters;
9287 /* remove existing filters, if any */
9288 perf_addr_filters_splice(event, &filters);
9290 /* install new filters */
9291 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9296 free_filters_list(&filters);
9299 event->addr_filters.nr_file_filters = 0;
9304 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9309 filter_str = strndup_user(arg, PAGE_SIZE);
9310 if (IS_ERR(filter_str))
9311 return PTR_ERR(filter_str);
9313 #ifdef CONFIG_EVENT_TRACING
9314 if (perf_event_is_tracing(event)) {
9315 struct perf_event_context *ctx = event->ctx;
9318 * Beware, here be dragons!!
9320 * the tracepoint muck will deadlock against ctx->mutex, but
9321 * the tracepoint stuff does not actually need it. So
9322 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9323 * already have a reference on ctx.
9325 * This can result in event getting moved to a different ctx,
9326 * but that does not affect the tracepoint state.
9328 mutex_unlock(&ctx->mutex);
9329 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9330 mutex_lock(&ctx->mutex);
9333 if (has_addr_filter(event))
9334 ret = perf_event_set_addr_filter(event, filter_str);
9341 * hrtimer based swevent callback
9344 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9346 enum hrtimer_restart ret = HRTIMER_RESTART;
9347 struct perf_sample_data data;
9348 struct pt_regs *regs;
9349 struct perf_event *event;
9352 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9354 if (event->state != PERF_EVENT_STATE_ACTIVE)
9355 return HRTIMER_NORESTART;
9357 event->pmu->read(event);
9359 perf_sample_data_init(&data, 0, event->hw.last_period);
9360 regs = get_irq_regs();
9362 if (regs && !perf_exclude_event(event, regs)) {
9363 if (!(event->attr.exclude_idle && is_idle_task(current)))
9364 if (__perf_event_overflow(event, 1, &data, regs))
9365 ret = HRTIMER_NORESTART;
9368 period = max_t(u64, 10000, event->hw.sample_period);
9369 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9374 static void perf_swevent_start_hrtimer(struct perf_event *event)
9376 struct hw_perf_event *hwc = &event->hw;
9379 if (!is_sampling_event(event))
9382 period = local64_read(&hwc->period_left);
9387 local64_set(&hwc->period_left, 0);
9389 period = max_t(u64, 10000, hwc->sample_period);
9391 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9392 HRTIMER_MODE_REL_PINNED);
9395 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9397 struct hw_perf_event *hwc = &event->hw;
9399 if (is_sampling_event(event)) {
9400 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9401 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9403 hrtimer_cancel(&hwc->hrtimer);
9407 static void perf_swevent_init_hrtimer(struct perf_event *event)
9409 struct hw_perf_event *hwc = &event->hw;
9411 if (!is_sampling_event(event))
9414 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9415 hwc->hrtimer.function = perf_swevent_hrtimer;
9418 * Since hrtimers have a fixed rate, we can do a static freq->period
9419 * mapping and avoid the whole period adjust feedback stuff.
9421 if (event->attr.freq) {
9422 long freq = event->attr.sample_freq;
9424 event->attr.sample_period = NSEC_PER_SEC / freq;
9425 hwc->sample_period = event->attr.sample_period;
9426 local64_set(&hwc->period_left, hwc->sample_period);
9427 hwc->last_period = hwc->sample_period;
9428 event->attr.freq = 0;
9433 * Software event: cpu wall time clock
9436 static void cpu_clock_event_update(struct perf_event *event)
9441 now = local_clock();
9442 prev = local64_xchg(&event->hw.prev_count, now);
9443 local64_add(now - prev, &event->count);
9446 static void cpu_clock_event_start(struct perf_event *event, int flags)
9448 local64_set(&event->hw.prev_count, local_clock());
9449 perf_swevent_start_hrtimer(event);
9452 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9454 perf_swevent_cancel_hrtimer(event);
9455 cpu_clock_event_update(event);
9458 static int cpu_clock_event_add(struct perf_event *event, int flags)
9460 if (flags & PERF_EF_START)
9461 cpu_clock_event_start(event, flags);
9462 perf_event_update_userpage(event);
9467 static void cpu_clock_event_del(struct perf_event *event, int flags)
9469 cpu_clock_event_stop(event, flags);
9472 static void cpu_clock_event_read(struct perf_event *event)
9474 cpu_clock_event_update(event);
9477 static int cpu_clock_event_init(struct perf_event *event)
9479 if (event->attr.type != PERF_TYPE_SOFTWARE)
9482 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9486 * no branch sampling for software events
9488 if (has_branch_stack(event))
9491 perf_swevent_init_hrtimer(event);
9496 static struct pmu perf_cpu_clock = {
9497 .task_ctx_nr = perf_sw_context,
9499 .capabilities = PERF_PMU_CAP_NO_NMI,
9501 .event_init = cpu_clock_event_init,
9502 .add = cpu_clock_event_add,
9503 .del = cpu_clock_event_del,
9504 .start = cpu_clock_event_start,
9505 .stop = cpu_clock_event_stop,
9506 .read = cpu_clock_event_read,
9510 * Software event: task time clock
9513 static void task_clock_event_update(struct perf_event *event, u64 now)
9518 prev = local64_xchg(&event->hw.prev_count, now);
9520 local64_add(delta, &event->count);
9523 static void task_clock_event_start(struct perf_event *event, int flags)
9525 local64_set(&event->hw.prev_count, event->ctx->time);
9526 perf_swevent_start_hrtimer(event);
9529 static void task_clock_event_stop(struct perf_event *event, int flags)
9531 perf_swevent_cancel_hrtimer(event);
9532 task_clock_event_update(event, event->ctx->time);
9535 static int task_clock_event_add(struct perf_event *event, int flags)
9537 if (flags & PERF_EF_START)
9538 task_clock_event_start(event, flags);
9539 perf_event_update_userpage(event);
9544 static void task_clock_event_del(struct perf_event *event, int flags)
9546 task_clock_event_stop(event, PERF_EF_UPDATE);
9549 static void task_clock_event_read(struct perf_event *event)
9551 u64 now = perf_clock();
9552 u64 delta = now - event->ctx->timestamp;
9553 u64 time = event->ctx->time + delta;
9555 task_clock_event_update(event, time);
9558 static int task_clock_event_init(struct perf_event *event)
9560 if (event->attr.type != PERF_TYPE_SOFTWARE)
9563 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9567 * no branch sampling for software events
9569 if (has_branch_stack(event))
9572 perf_swevent_init_hrtimer(event);
9577 static struct pmu perf_task_clock = {
9578 .task_ctx_nr = perf_sw_context,
9580 .capabilities = PERF_PMU_CAP_NO_NMI,
9582 .event_init = task_clock_event_init,
9583 .add = task_clock_event_add,
9584 .del = task_clock_event_del,
9585 .start = task_clock_event_start,
9586 .stop = task_clock_event_stop,
9587 .read = task_clock_event_read,
9590 static void perf_pmu_nop_void(struct pmu *pmu)
9594 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9598 static int perf_pmu_nop_int(struct pmu *pmu)
9603 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9605 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9607 __this_cpu_write(nop_txn_flags, flags);
9609 if (flags & ~PERF_PMU_TXN_ADD)
9612 perf_pmu_disable(pmu);
9615 static int perf_pmu_commit_txn(struct pmu *pmu)
9617 unsigned int flags = __this_cpu_read(nop_txn_flags);
9619 __this_cpu_write(nop_txn_flags, 0);
9621 if (flags & ~PERF_PMU_TXN_ADD)
9624 perf_pmu_enable(pmu);
9628 static void perf_pmu_cancel_txn(struct pmu *pmu)
9630 unsigned int flags = __this_cpu_read(nop_txn_flags);
9632 __this_cpu_write(nop_txn_flags, 0);
9634 if (flags & ~PERF_PMU_TXN_ADD)
9637 perf_pmu_enable(pmu);
9640 static int perf_event_idx_default(struct perf_event *event)
9646 * Ensures all contexts with the same task_ctx_nr have the same
9647 * pmu_cpu_context too.
9649 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9656 list_for_each_entry(pmu, &pmus, entry) {
9657 if (pmu->task_ctx_nr == ctxn)
9658 return pmu->pmu_cpu_context;
9664 static void free_pmu_context(struct pmu *pmu)
9667 * Static contexts such as perf_sw_context have a global lifetime
9668 * and may be shared between different PMUs. Avoid freeing them
9669 * when a single PMU is going away.
9671 if (pmu->task_ctx_nr > perf_invalid_context)
9674 free_percpu(pmu->pmu_cpu_context);
9678 * Let userspace know that this PMU supports address range filtering:
9680 static ssize_t nr_addr_filters_show(struct device *dev,
9681 struct device_attribute *attr,
9684 struct pmu *pmu = dev_get_drvdata(dev);
9686 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9688 DEVICE_ATTR_RO(nr_addr_filters);
9690 static struct idr pmu_idr;
9693 type_show(struct device *dev, struct device_attribute *attr, char *page)
9695 struct pmu *pmu = dev_get_drvdata(dev);
9697 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9699 static DEVICE_ATTR_RO(type);
9702 perf_event_mux_interval_ms_show(struct device *dev,
9703 struct device_attribute *attr,
9706 struct pmu *pmu = dev_get_drvdata(dev);
9708 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9711 static DEFINE_MUTEX(mux_interval_mutex);
9714 perf_event_mux_interval_ms_store(struct device *dev,
9715 struct device_attribute *attr,
9716 const char *buf, size_t count)
9718 struct pmu *pmu = dev_get_drvdata(dev);
9719 int timer, cpu, ret;
9721 ret = kstrtoint(buf, 0, &timer);
9728 /* same value, noting to do */
9729 if (timer == pmu->hrtimer_interval_ms)
9732 mutex_lock(&mux_interval_mutex);
9733 pmu->hrtimer_interval_ms = timer;
9735 /* update all cpuctx for this PMU */
9737 for_each_online_cpu(cpu) {
9738 struct perf_cpu_context *cpuctx;
9739 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9740 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9742 cpu_function_call(cpu,
9743 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9746 mutex_unlock(&mux_interval_mutex);
9750 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9752 static struct attribute *pmu_dev_attrs[] = {
9753 &dev_attr_type.attr,
9754 &dev_attr_perf_event_mux_interval_ms.attr,
9757 ATTRIBUTE_GROUPS(pmu_dev);
9759 static int pmu_bus_running;
9760 static struct bus_type pmu_bus = {
9761 .name = "event_source",
9762 .dev_groups = pmu_dev_groups,
9765 static void pmu_dev_release(struct device *dev)
9770 static int pmu_dev_alloc(struct pmu *pmu)
9774 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9778 pmu->dev->groups = pmu->attr_groups;
9779 device_initialize(pmu->dev);
9780 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9784 dev_set_drvdata(pmu->dev, pmu);
9785 pmu->dev->bus = &pmu_bus;
9786 pmu->dev->release = pmu_dev_release;
9787 ret = device_add(pmu->dev);
9791 /* For PMUs with address filters, throw in an extra attribute: */
9792 if (pmu->nr_addr_filters)
9793 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9802 device_del(pmu->dev);
9805 put_device(pmu->dev);
9809 static struct lock_class_key cpuctx_mutex;
9810 static struct lock_class_key cpuctx_lock;
9812 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9816 mutex_lock(&pmus_lock);
9818 pmu->pmu_disable_count = alloc_percpu(int);
9819 if (!pmu->pmu_disable_count)
9828 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9836 if (pmu_bus_running) {
9837 ret = pmu_dev_alloc(pmu);
9843 if (pmu->task_ctx_nr == perf_hw_context) {
9844 static int hw_context_taken = 0;
9847 * Other than systems with heterogeneous CPUs, it never makes
9848 * sense for two PMUs to share perf_hw_context. PMUs which are
9849 * uncore must use perf_invalid_context.
9851 if (WARN_ON_ONCE(hw_context_taken &&
9852 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9853 pmu->task_ctx_nr = perf_invalid_context;
9855 hw_context_taken = 1;
9858 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9859 if (pmu->pmu_cpu_context)
9860 goto got_cpu_context;
9863 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9864 if (!pmu->pmu_cpu_context)
9867 for_each_possible_cpu(cpu) {
9868 struct perf_cpu_context *cpuctx;
9870 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9871 __perf_event_init_context(&cpuctx->ctx);
9872 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9873 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9874 cpuctx->ctx.pmu = pmu;
9875 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9877 __perf_mux_hrtimer_init(cpuctx, cpu);
9881 if (!pmu->start_txn) {
9882 if (pmu->pmu_enable) {
9884 * If we have pmu_enable/pmu_disable calls, install
9885 * transaction stubs that use that to try and batch
9886 * hardware accesses.
9888 pmu->start_txn = perf_pmu_start_txn;
9889 pmu->commit_txn = perf_pmu_commit_txn;
9890 pmu->cancel_txn = perf_pmu_cancel_txn;
9892 pmu->start_txn = perf_pmu_nop_txn;
9893 pmu->commit_txn = perf_pmu_nop_int;
9894 pmu->cancel_txn = perf_pmu_nop_void;
9898 if (!pmu->pmu_enable) {
9899 pmu->pmu_enable = perf_pmu_nop_void;
9900 pmu->pmu_disable = perf_pmu_nop_void;
9903 if (!pmu->event_idx)
9904 pmu->event_idx = perf_event_idx_default;
9906 list_add_rcu(&pmu->entry, &pmus);
9907 atomic_set(&pmu->exclusive_cnt, 0);
9910 mutex_unlock(&pmus_lock);
9915 device_del(pmu->dev);
9916 put_device(pmu->dev);
9919 if (pmu->type >= PERF_TYPE_MAX)
9920 idr_remove(&pmu_idr, pmu->type);
9923 free_percpu(pmu->pmu_disable_count);
9926 EXPORT_SYMBOL_GPL(perf_pmu_register);
9928 void perf_pmu_unregister(struct pmu *pmu)
9930 mutex_lock(&pmus_lock);
9931 list_del_rcu(&pmu->entry);
9934 * We dereference the pmu list under both SRCU and regular RCU, so
9935 * synchronize against both of those.
9937 synchronize_srcu(&pmus_srcu);
9940 free_percpu(pmu->pmu_disable_count);
9941 if (pmu->type >= PERF_TYPE_MAX)
9942 idr_remove(&pmu_idr, pmu->type);
9943 if (pmu_bus_running) {
9944 if (pmu->nr_addr_filters)
9945 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9946 device_del(pmu->dev);
9947 put_device(pmu->dev);
9949 free_pmu_context(pmu);
9950 mutex_unlock(&pmus_lock);
9952 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9954 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9956 struct perf_event_context *ctx = NULL;
9959 if (!try_module_get(pmu->module))
9963 * A number of pmu->event_init() methods iterate the sibling_list to,
9964 * for example, validate if the group fits on the PMU. Therefore,
9965 * if this is a sibling event, acquire the ctx->mutex to protect
9968 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9970 * This ctx->mutex can nest when we're called through
9971 * inheritance. See the perf_event_ctx_lock_nested() comment.
9973 ctx = perf_event_ctx_lock_nested(event->group_leader,
9974 SINGLE_DEPTH_NESTING);
9979 ret = pmu->event_init(event);
9982 perf_event_ctx_unlock(event->group_leader, ctx);
9985 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
9986 event_has_any_exclude_flag(event)) {
9988 event->destroy(event);
9994 module_put(pmu->module);
9999 static struct pmu *perf_init_event(struct perf_event *event)
10005 idx = srcu_read_lock(&pmus_srcu);
10007 /* Try parent's PMU first: */
10008 if (event->parent && event->parent->pmu) {
10009 pmu = event->parent->pmu;
10010 ret = perf_try_init_event(pmu, event);
10016 pmu = idr_find(&pmu_idr, event->attr.type);
10019 ret = perf_try_init_event(pmu, event);
10021 pmu = ERR_PTR(ret);
10025 list_for_each_entry_rcu(pmu, &pmus, entry) {
10026 ret = perf_try_init_event(pmu, event);
10030 if (ret != -ENOENT) {
10031 pmu = ERR_PTR(ret);
10035 pmu = ERR_PTR(-ENOENT);
10037 srcu_read_unlock(&pmus_srcu, idx);
10042 static void attach_sb_event(struct perf_event *event)
10044 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10046 raw_spin_lock(&pel->lock);
10047 list_add_rcu(&event->sb_list, &pel->list);
10048 raw_spin_unlock(&pel->lock);
10052 * We keep a list of all !task (and therefore per-cpu) events
10053 * that need to receive side-band records.
10055 * This avoids having to scan all the various PMU per-cpu contexts
10056 * looking for them.
10058 static void account_pmu_sb_event(struct perf_event *event)
10060 if (is_sb_event(event))
10061 attach_sb_event(event);
10064 static void account_event_cpu(struct perf_event *event, int cpu)
10069 if (is_cgroup_event(event))
10070 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10073 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10074 static void account_freq_event_nohz(void)
10076 #ifdef CONFIG_NO_HZ_FULL
10077 /* Lock so we don't race with concurrent unaccount */
10078 spin_lock(&nr_freq_lock);
10079 if (atomic_inc_return(&nr_freq_events) == 1)
10080 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10081 spin_unlock(&nr_freq_lock);
10085 static void account_freq_event(void)
10087 if (tick_nohz_full_enabled())
10088 account_freq_event_nohz();
10090 atomic_inc(&nr_freq_events);
10094 static void account_event(struct perf_event *event)
10101 if (event->attach_state & PERF_ATTACH_TASK)
10103 if (event->attr.mmap || event->attr.mmap_data)
10104 atomic_inc(&nr_mmap_events);
10105 if (event->attr.comm)
10106 atomic_inc(&nr_comm_events);
10107 if (event->attr.namespaces)
10108 atomic_inc(&nr_namespaces_events);
10109 if (event->attr.task)
10110 atomic_inc(&nr_task_events);
10111 if (event->attr.freq)
10112 account_freq_event();
10113 if (event->attr.context_switch) {
10114 atomic_inc(&nr_switch_events);
10117 if (has_branch_stack(event))
10119 if (is_cgroup_event(event))
10121 if (event->attr.ksymbol)
10122 atomic_inc(&nr_ksymbol_events);
10123 if (event->attr.bpf_event)
10124 atomic_inc(&nr_bpf_events);
10128 * We need the mutex here because static_branch_enable()
10129 * must complete *before* the perf_sched_count increment
10132 if (atomic_inc_not_zero(&perf_sched_count))
10135 mutex_lock(&perf_sched_mutex);
10136 if (!atomic_read(&perf_sched_count)) {
10137 static_branch_enable(&perf_sched_events);
10139 * Guarantee that all CPUs observe they key change and
10140 * call the perf scheduling hooks before proceeding to
10141 * install events that need them.
10146 * Now that we have waited for the sync_sched(), allow further
10147 * increments to by-pass the mutex.
10149 atomic_inc(&perf_sched_count);
10150 mutex_unlock(&perf_sched_mutex);
10154 account_event_cpu(event, event->cpu);
10156 account_pmu_sb_event(event);
10160 * Allocate and initialize an event structure
10162 static struct perf_event *
10163 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10164 struct task_struct *task,
10165 struct perf_event *group_leader,
10166 struct perf_event *parent_event,
10167 perf_overflow_handler_t overflow_handler,
10168 void *context, int cgroup_fd)
10171 struct perf_event *event;
10172 struct hw_perf_event *hwc;
10173 long err = -EINVAL;
10175 if ((unsigned)cpu >= nr_cpu_ids) {
10176 if (!task || cpu != -1)
10177 return ERR_PTR(-EINVAL);
10180 event = kzalloc(sizeof(*event), GFP_KERNEL);
10182 return ERR_PTR(-ENOMEM);
10185 * Single events are their own group leaders, with an
10186 * empty sibling list:
10189 group_leader = event;
10191 mutex_init(&event->child_mutex);
10192 INIT_LIST_HEAD(&event->child_list);
10194 INIT_LIST_HEAD(&event->event_entry);
10195 INIT_LIST_HEAD(&event->sibling_list);
10196 INIT_LIST_HEAD(&event->active_list);
10197 init_event_group(event);
10198 INIT_LIST_HEAD(&event->rb_entry);
10199 INIT_LIST_HEAD(&event->active_entry);
10200 INIT_LIST_HEAD(&event->addr_filters.list);
10201 INIT_HLIST_NODE(&event->hlist_entry);
10204 init_waitqueue_head(&event->waitq);
10205 init_irq_work(&event->pending, perf_pending_event);
10207 mutex_init(&event->mmap_mutex);
10208 raw_spin_lock_init(&event->addr_filters.lock);
10210 atomic_long_set(&event->refcount, 1);
10212 event->attr = *attr;
10213 event->group_leader = group_leader;
10217 event->parent = parent_event;
10219 event->ns = get_pid_ns(task_active_pid_ns(current));
10220 event->id = atomic64_inc_return(&perf_event_id);
10222 event->state = PERF_EVENT_STATE_INACTIVE;
10225 event->attach_state = PERF_ATTACH_TASK;
10227 * XXX pmu::event_init needs to know what task to account to
10228 * and we cannot use the ctx information because we need the
10229 * pmu before we get a ctx.
10231 get_task_struct(task);
10232 event->hw.target = task;
10235 event->clock = &local_clock;
10237 event->clock = parent_event->clock;
10239 if (!overflow_handler && parent_event) {
10240 overflow_handler = parent_event->overflow_handler;
10241 context = parent_event->overflow_handler_context;
10242 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10243 if (overflow_handler == bpf_overflow_handler) {
10244 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10246 if (IS_ERR(prog)) {
10247 err = PTR_ERR(prog);
10250 event->prog = prog;
10251 event->orig_overflow_handler =
10252 parent_event->orig_overflow_handler;
10257 if (overflow_handler) {
10258 event->overflow_handler = overflow_handler;
10259 event->overflow_handler_context = context;
10260 } else if (is_write_backward(event)){
10261 event->overflow_handler = perf_event_output_backward;
10262 event->overflow_handler_context = NULL;
10264 event->overflow_handler = perf_event_output_forward;
10265 event->overflow_handler_context = NULL;
10268 perf_event__state_init(event);
10273 hwc->sample_period = attr->sample_period;
10274 if (attr->freq && attr->sample_freq)
10275 hwc->sample_period = 1;
10276 hwc->last_period = hwc->sample_period;
10278 local64_set(&hwc->period_left, hwc->sample_period);
10281 * We currently do not support PERF_SAMPLE_READ on inherited events.
10282 * See perf_output_read().
10284 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10287 if (!has_branch_stack(event))
10288 event->attr.branch_sample_type = 0;
10290 if (cgroup_fd != -1) {
10291 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10296 pmu = perf_init_event(event);
10298 err = PTR_ERR(pmu);
10302 err = exclusive_event_init(event);
10306 if (has_addr_filter(event)) {
10307 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
10308 sizeof(unsigned long),
10310 if (!event->addr_filters_offs) {
10315 /* force hw sync on the address filters */
10316 event->addr_filters_gen = 1;
10319 if (!event->parent) {
10320 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10321 err = get_callchain_buffers(attr->sample_max_stack);
10323 goto err_addr_filters;
10327 /* symmetric to unaccount_event() in _free_event() */
10328 account_event(event);
10333 kfree(event->addr_filters_offs);
10336 exclusive_event_destroy(event);
10339 if (event->destroy)
10340 event->destroy(event);
10341 module_put(pmu->module);
10343 if (is_cgroup_event(event))
10344 perf_detach_cgroup(event);
10346 put_pid_ns(event->ns);
10347 if (event->hw.target)
10348 put_task_struct(event->hw.target);
10351 return ERR_PTR(err);
10354 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10355 struct perf_event_attr *attr)
10360 if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
10364 * zero the full structure, so that a short copy will be nice.
10366 memset(attr, 0, sizeof(*attr));
10368 ret = get_user(size, &uattr->size);
10372 if (size > PAGE_SIZE) /* silly large */
10375 if (!size) /* abi compat */
10376 size = PERF_ATTR_SIZE_VER0;
10378 if (size < PERF_ATTR_SIZE_VER0)
10382 * If we're handed a bigger struct than we know of,
10383 * ensure all the unknown bits are 0 - i.e. new
10384 * user-space does not rely on any kernel feature
10385 * extensions we dont know about yet.
10387 if (size > sizeof(*attr)) {
10388 unsigned char __user *addr;
10389 unsigned char __user *end;
10392 addr = (void __user *)uattr + sizeof(*attr);
10393 end = (void __user *)uattr + size;
10395 for (; addr < end; addr++) {
10396 ret = get_user(val, addr);
10402 size = sizeof(*attr);
10405 ret = copy_from_user(attr, uattr, size);
10411 if (attr->__reserved_1)
10414 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10417 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10420 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10421 u64 mask = attr->branch_sample_type;
10423 /* only using defined bits */
10424 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10427 /* at least one branch bit must be set */
10428 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10431 /* propagate priv level, when not set for branch */
10432 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10434 /* exclude_kernel checked on syscall entry */
10435 if (!attr->exclude_kernel)
10436 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10438 if (!attr->exclude_user)
10439 mask |= PERF_SAMPLE_BRANCH_USER;
10441 if (!attr->exclude_hv)
10442 mask |= PERF_SAMPLE_BRANCH_HV;
10444 * adjust user setting (for HW filter setup)
10446 attr->branch_sample_type = mask;
10448 /* privileged levels capture (kernel, hv): check permissions */
10449 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10450 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10454 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10455 ret = perf_reg_validate(attr->sample_regs_user);
10460 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10461 if (!arch_perf_have_user_stack_dump())
10465 * We have __u32 type for the size, but so far
10466 * we can only use __u16 as maximum due to the
10467 * __u16 sample size limit.
10469 if (attr->sample_stack_user >= USHRT_MAX)
10471 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10475 if (!attr->sample_max_stack)
10476 attr->sample_max_stack = sysctl_perf_event_max_stack;
10478 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10479 ret = perf_reg_validate(attr->sample_regs_intr);
10484 put_user(sizeof(*attr), &uattr->size);
10490 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10492 struct ring_buffer *rb = NULL;
10498 /* don't allow circular references */
10499 if (event == output_event)
10503 * Don't allow cross-cpu buffers
10505 if (output_event->cpu != event->cpu)
10509 * If its not a per-cpu rb, it must be the same task.
10511 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10515 * Mixing clocks in the same buffer is trouble you don't need.
10517 if (output_event->clock != event->clock)
10521 * Either writing ring buffer from beginning or from end.
10522 * Mixing is not allowed.
10524 if (is_write_backward(output_event) != is_write_backward(event))
10528 * If both events generate aux data, they must be on the same PMU
10530 if (has_aux(event) && has_aux(output_event) &&
10531 event->pmu != output_event->pmu)
10535 mutex_lock(&event->mmap_mutex);
10536 /* Can't redirect output if we've got an active mmap() */
10537 if (atomic_read(&event->mmap_count))
10540 if (output_event) {
10541 /* get the rb we want to redirect to */
10542 rb = ring_buffer_get(output_event);
10547 ring_buffer_attach(event, rb);
10551 mutex_unlock(&event->mmap_mutex);
10557 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10563 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10566 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10568 bool nmi_safe = false;
10571 case CLOCK_MONOTONIC:
10572 event->clock = &ktime_get_mono_fast_ns;
10576 case CLOCK_MONOTONIC_RAW:
10577 event->clock = &ktime_get_raw_fast_ns;
10581 case CLOCK_REALTIME:
10582 event->clock = &ktime_get_real_ns;
10585 case CLOCK_BOOTTIME:
10586 event->clock = &ktime_get_boot_ns;
10590 event->clock = &ktime_get_tai_ns;
10597 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10604 * Variation on perf_event_ctx_lock_nested(), except we take two context
10607 static struct perf_event_context *
10608 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10609 struct perf_event_context *ctx)
10611 struct perf_event_context *gctx;
10615 gctx = READ_ONCE(group_leader->ctx);
10616 if (!refcount_inc_not_zero(&gctx->refcount)) {
10622 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10624 if (group_leader->ctx != gctx) {
10625 mutex_unlock(&ctx->mutex);
10626 mutex_unlock(&gctx->mutex);
10635 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10637 * @attr_uptr: event_id type attributes for monitoring/sampling
10640 * @group_fd: group leader event fd
10642 SYSCALL_DEFINE5(perf_event_open,
10643 struct perf_event_attr __user *, attr_uptr,
10644 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10646 struct perf_event *group_leader = NULL, *output_event = NULL;
10647 struct perf_event *event, *sibling;
10648 struct perf_event_attr attr;
10649 struct perf_event_context *ctx, *uninitialized_var(gctx);
10650 struct file *event_file = NULL;
10651 struct fd group = {NULL, 0};
10652 struct task_struct *task = NULL;
10655 int move_group = 0;
10657 int f_flags = O_RDWR;
10658 int cgroup_fd = -1;
10660 /* for future expandability... */
10661 if (flags & ~PERF_FLAG_ALL)
10664 err = perf_copy_attr(attr_uptr, &attr);
10668 if (!attr.exclude_kernel) {
10669 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10673 if (attr.namespaces) {
10674 if (!capable(CAP_SYS_ADMIN))
10679 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10682 if (attr.sample_period & (1ULL << 63))
10686 /* Only privileged users can get physical addresses */
10687 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10688 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10692 * In cgroup mode, the pid argument is used to pass the fd
10693 * opened to the cgroup directory in cgroupfs. The cpu argument
10694 * designates the cpu on which to monitor threads from that
10697 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10700 if (flags & PERF_FLAG_FD_CLOEXEC)
10701 f_flags |= O_CLOEXEC;
10703 event_fd = get_unused_fd_flags(f_flags);
10707 if (group_fd != -1) {
10708 err = perf_fget_light(group_fd, &group);
10711 group_leader = group.file->private_data;
10712 if (flags & PERF_FLAG_FD_OUTPUT)
10713 output_event = group_leader;
10714 if (flags & PERF_FLAG_FD_NO_GROUP)
10715 group_leader = NULL;
10718 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10719 task = find_lively_task_by_vpid(pid);
10720 if (IS_ERR(task)) {
10721 err = PTR_ERR(task);
10726 if (task && group_leader &&
10727 group_leader->attr.inherit != attr.inherit) {
10733 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10738 * Reuse ptrace permission checks for now.
10740 * We must hold cred_guard_mutex across this and any potential
10741 * perf_install_in_context() call for this new event to
10742 * serialize against exec() altering our credentials (and the
10743 * perf_event_exit_task() that could imply).
10746 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10750 if (flags & PERF_FLAG_PID_CGROUP)
10753 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10754 NULL, NULL, cgroup_fd);
10755 if (IS_ERR(event)) {
10756 err = PTR_ERR(event);
10760 if (is_sampling_event(event)) {
10761 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10768 * Special case software events and allow them to be part of
10769 * any hardware group.
10773 if (attr.use_clockid) {
10774 err = perf_event_set_clock(event, attr.clockid);
10779 if (pmu->task_ctx_nr == perf_sw_context)
10780 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10782 if (group_leader) {
10783 if (is_software_event(event) &&
10784 !in_software_context(group_leader)) {
10786 * If the event is a sw event, but the group_leader
10787 * is on hw context.
10789 * Allow the addition of software events to hw
10790 * groups, this is safe because software events
10791 * never fail to schedule.
10793 pmu = group_leader->ctx->pmu;
10794 } else if (!is_software_event(event) &&
10795 is_software_event(group_leader) &&
10796 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10798 * In case the group is a pure software group, and we
10799 * try to add a hardware event, move the whole group to
10800 * the hardware context.
10807 * Get the target context (task or percpu):
10809 ctx = find_get_context(pmu, task, event);
10811 err = PTR_ERR(ctx);
10815 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10821 * Look up the group leader (we will attach this event to it):
10823 if (group_leader) {
10827 * Do not allow a recursive hierarchy (this new sibling
10828 * becoming part of another group-sibling):
10830 if (group_leader->group_leader != group_leader)
10833 /* All events in a group should have the same clock */
10834 if (group_leader->clock != event->clock)
10838 * Make sure we're both events for the same CPU;
10839 * grouping events for different CPUs is broken; since
10840 * you can never concurrently schedule them anyhow.
10842 if (group_leader->cpu != event->cpu)
10846 * Make sure we're both on the same task, or both
10849 if (group_leader->ctx->task != ctx->task)
10853 * Do not allow to attach to a group in a different task
10854 * or CPU context. If we're moving SW events, we'll fix
10855 * this up later, so allow that.
10857 if (!move_group && group_leader->ctx != ctx)
10861 * Only a group leader can be exclusive or pinned
10863 if (attr.exclusive || attr.pinned)
10867 if (output_event) {
10868 err = perf_event_set_output(event, output_event);
10873 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10875 if (IS_ERR(event_file)) {
10876 err = PTR_ERR(event_file);
10882 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10884 if (gctx->task == TASK_TOMBSTONE) {
10890 * Check if we raced against another sys_perf_event_open() call
10891 * moving the software group underneath us.
10893 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10895 * If someone moved the group out from under us, check
10896 * if this new event wound up on the same ctx, if so
10897 * its the regular !move_group case, otherwise fail.
10903 perf_event_ctx_unlock(group_leader, gctx);
10908 mutex_lock(&ctx->mutex);
10911 if (ctx->task == TASK_TOMBSTONE) {
10916 if (!perf_event_validate_size(event)) {
10923 * Check if the @cpu we're creating an event for is online.
10925 * We use the perf_cpu_context::ctx::mutex to serialize against
10926 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10928 struct perf_cpu_context *cpuctx =
10929 container_of(ctx, struct perf_cpu_context, ctx);
10931 if (!cpuctx->online) {
10939 * Must be under the same ctx::mutex as perf_install_in_context(),
10940 * because we need to serialize with concurrent event creation.
10942 if (!exclusive_event_installable(event, ctx)) {
10943 /* exclusive and group stuff are assumed mutually exclusive */
10944 WARN_ON_ONCE(move_group);
10950 WARN_ON_ONCE(ctx->parent_ctx);
10953 * This is the point on no return; we cannot fail hereafter. This is
10954 * where we start modifying current state.
10959 * See perf_event_ctx_lock() for comments on the details
10960 * of swizzling perf_event::ctx.
10962 perf_remove_from_context(group_leader, 0);
10965 for_each_sibling_event(sibling, group_leader) {
10966 perf_remove_from_context(sibling, 0);
10971 * Wait for everybody to stop referencing the events through
10972 * the old lists, before installing it on new lists.
10977 * Install the group siblings before the group leader.
10979 * Because a group leader will try and install the entire group
10980 * (through the sibling list, which is still in-tact), we can
10981 * end up with siblings installed in the wrong context.
10983 * By installing siblings first we NO-OP because they're not
10984 * reachable through the group lists.
10986 for_each_sibling_event(sibling, group_leader) {
10987 perf_event__state_init(sibling);
10988 perf_install_in_context(ctx, sibling, sibling->cpu);
10993 * Removing from the context ends up with disabled
10994 * event. What we want here is event in the initial
10995 * startup state, ready to be add into new context.
10997 perf_event__state_init(group_leader);
10998 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11003 * Precalculate sample_data sizes; do while holding ctx::mutex such
11004 * that we're serialized against further additions and before
11005 * perf_install_in_context() which is the point the event is active and
11006 * can use these values.
11008 perf_event__header_size(event);
11009 perf_event__id_header_size(event);
11011 event->owner = current;
11013 perf_install_in_context(ctx, event, event->cpu);
11014 perf_unpin_context(ctx);
11017 perf_event_ctx_unlock(group_leader, gctx);
11018 mutex_unlock(&ctx->mutex);
11021 mutex_unlock(&task->signal->cred_guard_mutex);
11022 put_task_struct(task);
11025 mutex_lock(¤t->perf_event_mutex);
11026 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11027 mutex_unlock(¤t->perf_event_mutex);
11030 * Drop the reference on the group_event after placing the
11031 * new event on the sibling_list. This ensures destruction
11032 * of the group leader will find the pointer to itself in
11033 * perf_group_detach().
11036 fd_install(event_fd, event_file);
11041 perf_event_ctx_unlock(group_leader, gctx);
11042 mutex_unlock(&ctx->mutex);
11046 perf_unpin_context(ctx);
11050 * If event_file is set, the fput() above will have called ->release()
11051 * and that will take care of freeing the event.
11057 mutex_unlock(&task->signal->cred_guard_mutex);
11060 put_task_struct(task);
11064 put_unused_fd(event_fd);
11069 * perf_event_create_kernel_counter
11071 * @attr: attributes of the counter to create
11072 * @cpu: cpu in which the counter is bound
11073 * @task: task to profile (NULL for percpu)
11075 struct perf_event *
11076 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11077 struct task_struct *task,
11078 perf_overflow_handler_t overflow_handler,
11081 struct perf_event_context *ctx;
11082 struct perf_event *event;
11086 * Get the target context (task or percpu):
11089 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11090 overflow_handler, context, -1);
11091 if (IS_ERR(event)) {
11092 err = PTR_ERR(event);
11096 /* Mark owner so we could distinguish it from user events. */
11097 event->owner = TASK_TOMBSTONE;
11099 ctx = find_get_context(event->pmu, task, event);
11101 err = PTR_ERR(ctx);
11105 WARN_ON_ONCE(ctx->parent_ctx);
11106 mutex_lock(&ctx->mutex);
11107 if (ctx->task == TASK_TOMBSTONE) {
11114 * Check if the @cpu we're creating an event for is online.
11116 * We use the perf_cpu_context::ctx::mutex to serialize against
11117 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11119 struct perf_cpu_context *cpuctx =
11120 container_of(ctx, struct perf_cpu_context, ctx);
11121 if (!cpuctx->online) {
11127 if (!exclusive_event_installable(event, ctx)) {
11132 perf_install_in_context(ctx, event, cpu);
11133 perf_unpin_context(ctx);
11134 mutex_unlock(&ctx->mutex);
11139 mutex_unlock(&ctx->mutex);
11140 perf_unpin_context(ctx);
11145 return ERR_PTR(err);
11147 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11149 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11151 struct perf_event_context *src_ctx;
11152 struct perf_event_context *dst_ctx;
11153 struct perf_event *event, *tmp;
11156 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11157 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11160 * See perf_event_ctx_lock() for comments on the details
11161 * of swizzling perf_event::ctx.
11163 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11164 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11166 perf_remove_from_context(event, 0);
11167 unaccount_event_cpu(event, src_cpu);
11169 list_add(&event->migrate_entry, &events);
11173 * Wait for the events to quiesce before re-instating them.
11178 * Re-instate events in 2 passes.
11180 * Skip over group leaders and only install siblings on this first
11181 * pass, siblings will not get enabled without a leader, however a
11182 * leader will enable its siblings, even if those are still on the old
11185 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11186 if (event->group_leader == event)
11189 list_del(&event->migrate_entry);
11190 if (event->state >= PERF_EVENT_STATE_OFF)
11191 event->state = PERF_EVENT_STATE_INACTIVE;
11192 account_event_cpu(event, dst_cpu);
11193 perf_install_in_context(dst_ctx, event, dst_cpu);
11198 * Once all the siblings are setup properly, install the group leaders
11201 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11202 list_del(&event->migrate_entry);
11203 if (event->state >= PERF_EVENT_STATE_OFF)
11204 event->state = PERF_EVENT_STATE_INACTIVE;
11205 account_event_cpu(event, dst_cpu);
11206 perf_install_in_context(dst_ctx, event, dst_cpu);
11209 mutex_unlock(&dst_ctx->mutex);
11210 mutex_unlock(&src_ctx->mutex);
11212 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11214 static void sync_child_event(struct perf_event *child_event,
11215 struct task_struct *child)
11217 struct perf_event *parent_event = child_event->parent;
11220 if (child_event->attr.inherit_stat)
11221 perf_event_read_event(child_event, child);
11223 child_val = perf_event_count(child_event);
11226 * Add back the child's count to the parent's count:
11228 atomic64_add(child_val, &parent_event->child_count);
11229 atomic64_add(child_event->total_time_enabled,
11230 &parent_event->child_total_time_enabled);
11231 atomic64_add(child_event->total_time_running,
11232 &parent_event->child_total_time_running);
11236 perf_event_exit_event(struct perf_event *child_event,
11237 struct perf_event_context *child_ctx,
11238 struct task_struct *child)
11240 struct perf_event *parent_event = child_event->parent;
11243 * Do not destroy the 'original' grouping; because of the context
11244 * switch optimization the original events could've ended up in a
11245 * random child task.
11247 * If we were to destroy the original group, all group related
11248 * operations would cease to function properly after this random
11251 * Do destroy all inherited groups, we don't care about those
11252 * and being thorough is better.
11254 raw_spin_lock_irq(&child_ctx->lock);
11255 WARN_ON_ONCE(child_ctx->is_active);
11258 perf_group_detach(child_event);
11259 list_del_event(child_event, child_ctx);
11260 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11261 raw_spin_unlock_irq(&child_ctx->lock);
11264 * Parent events are governed by their filedesc, retain them.
11266 if (!parent_event) {
11267 perf_event_wakeup(child_event);
11271 * Child events can be cleaned up.
11274 sync_child_event(child_event, child);
11277 * Remove this event from the parent's list
11279 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11280 mutex_lock(&parent_event->child_mutex);
11281 list_del_init(&child_event->child_list);
11282 mutex_unlock(&parent_event->child_mutex);
11285 * Kick perf_poll() for is_event_hup().
11287 perf_event_wakeup(parent_event);
11288 free_event(child_event);
11289 put_event(parent_event);
11292 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11294 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11295 struct perf_event *child_event, *next;
11297 WARN_ON_ONCE(child != current);
11299 child_ctx = perf_pin_task_context(child, ctxn);
11304 * In order to reduce the amount of tricky in ctx tear-down, we hold
11305 * ctx::mutex over the entire thing. This serializes against almost
11306 * everything that wants to access the ctx.
11308 * The exception is sys_perf_event_open() /
11309 * perf_event_create_kernel_count() which does find_get_context()
11310 * without ctx::mutex (it cannot because of the move_group double mutex
11311 * lock thing). See the comments in perf_install_in_context().
11313 mutex_lock(&child_ctx->mutex);
11316 * In a single ctx::lock section, de-schedule the events and detach the
11317 * context from the task such that we cannot ever get it scheduled back
11320 raw_spin_lock_irq(&child_ctx->lock);
11321 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11324 * Now that the context is inactive, destroy the task <-> ctx relation
11325 * and mark the context dead.
11327 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11328 put_ctx(child_ctx); /* cannot be last */
11329 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11330 put_task_struct(current); /* cannot be last */
11332 clone_ctx = unclone_ctx(child_ctx);
11333 raw_spin_unlock_irq(&child_ctx->lock);
11336 put_ctx(clone_ctx);
11339 * Report the task dead after unscheduling the events so that we
11340 * won't get any samples after PERF_RECORD_EXIT. We can however still
11341 * get a few PERF_RECORD_READ events.
11343 perf_event_task(child, child_ctx, 0);
11345 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11346 perf_event_exit_event(child_event, child_ctx, child);
11348 mutex_unlock(&child_ctx->mutex);
11350 put_ctx(child_ctx);
11354 * When a child task exits, feed back event values to parent events.
11356 * Can be called with cred_guard_mutex held when called from
11357 * install_exec_creds().
11359 void perf_event_exit_task(struct task_struct *child)
11361 struct perf_event *event, *tmp;
11364 mutex_lock(&child->perf_event_mutex);
11365 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11367 list_del_init(&event->owner_entry);
11370 * Ensure the list deletion is visible before we clear
11371 * the owner, closes a race against perf_release() where
11372 * we need to serialize on the owner->perf_event_mutex.
11374 smp_store_release(&event->owner, NULL);
11376 mutex_unlock(&child->perf_event_mutex);
11378 for_each_task_context_nr(ctxn)
11379 perf_event_exit_task_context(child, ctxn);
11382 * The perf_event_exit_task_context calls perf_event_task
11383 * with child's task_ctx, which generates EXIT events for
11384 * child contexts and sets child->perf_event_ctxp[] to NULL.
11385 * At this point we need to send EXIT events to cpu contexts.
11387 perf_event_task(child, NULL, 0);
11390 static void perf_free_event(struct perf_event *event,
11391 struct perf_event_context *ctx)
11393 struct perf_event *parent = event->parent;
11395 if (WARN_ON_ONCE(!parent))
11398 mutex_lock(&parent->child_mutex);
11399 list_del_init(&event->child_list);
11400 mutex_unlock(&parent->child_mutex);
11404 raw_spin_lock_irq(&ctx->lock);
11405 perf_group_detach(event);
11406 list_del_event(event, ctx);
11407 raw_spin_unlock_irq(&ctx->lock);
11412 * Free an unexposed, unused context as created by inheritance by
11413 * perf_event_init_task below, used by fork() in case of fail.
11415 * Not all locks are strictly required, but take them anyway to be nice and
11416 * help out with the lockdep assertions.
11418 void perf_event_free_task(struct task_struct *task)
11420 struct perf_event_context *ctx;
11421 struct perf_event *event, *tmp;
11424 for_each_task_context_nr(ctxn) {
11425 ctx = task->perf_event_ctxp[ctxn];
11429 mutex_lock(&ctx->mutex);
11430 raw_spin_lock_irq(&ctx->lock);
11432 * Destroy the task <-> ctx relation and mark the context dead.
11434 * This is important because even though the task hasn't been
11435 * exposed yet the context has been (through child_list).
11437 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11438 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11439 put_task_struct(task); /* cannot be last */
11440 raw_spin_unlock_irq(&ctx->lock);
11442 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11443 perf_free_event(event, ctx);
11445 mutex_unlock(&ctx->mutex);
11450 void perf_event_delayed_put(struct task_struct *task)
11454 for_each_task_context_nr(ctxn)
11455 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11458 struct file *perf_event_get(unsigned int fd)
11462 file = fget_raw(fd);
11464 return ERR_PTR(-EBADF);
11466 if (file->f_op != &perf_fops) {
11468 return ERR_PTR(-EBADF);
11474 const struct perf_event *perf_get_event(struct file *file)
11476 if (file->f_op != &perf_fops)
11477 return ERR_PTR(-EINVAL);
11479 return file->private_data;
11482 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11485 return ERR_PTR(-EINVAL);
11487 return &event->attr;
11491 * Inherit an event from parent task to child task.
11494 * - valid pointer on success
11495 * - NULL for orphaned events
11496 * - IS_ERR() on error
11498 static struct perf_event *
11499 inherit_event(struct perf_event *parent_event,
11500 struct task_struct *parent,
11501 struct perf_event_context *parent_ctx,
11502 struct task_struct *child,
11503 struct perf_event *group_leader,
11504 struct perf_event_context *child_ctx)
11506 enum perf_event_state parent_state = parent_event->state;
11507 struct perf_event *child_event;
11508 unsigned long flags;
11511 * Instead of creating recursive hierarchies of events,
11512 * we link inherited events back to the original parent,
11513 * which has a filp for sure, which we use as the reference
11516 if (parent_event->parent)
11517 parent_event = parent_event->parent;
11519 child_event = perf_event_alloc(&parent_event->attr,
11522 group_leader, parent_event,
11524 if (IS_ERR(child_event))
11525 return child_event;
11528 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11529 !child_ctx->task_ctx_data) {
11530 struct pmu *pmu = child_event->pmu;
11532 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11534 if (!child_ctx->task_ctx_data) {
11535 free_event(child_event);
11541 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11542 * must be under the same lock in order to serialize against
11543 * perf_event_release_kernel(), such that either we must observe
11544 * is_orphaned_event() or they will observe us on the child_list.
11546 mutex_lock(&parent_event->child_mutex);
11547 if (is_orphaned_event(parent_event) ||
11548 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11549 mutex_unlock(&parent_event->child_mutex);
11550 /* task_ctx_data is freed with child_ctx */
11551 free_event(child_event);
11555 get_ctx(child_ctx);
11558 * Make the child state follow the state of the parent event,
11559 * not its attr.disabled bit. We hold the parent's mutex,
11560 * so we won't race with perf_event_{en, dis}able_family.
11562 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11563 child_event->state = PERF_EVENT_STATE_INACTIVE;
11565 child_event->state = PERF_EVENT_STATE_OFF;
11567 if (parent_event->attr.freq) {
11568 u64 sample_period = parent_event->hw.sample_period;
11569 struct hw_perf_event *hwc = &child_event->hw;
11571 hwc->sample_period = sample_period;
11572 hwc->last_period = sample_period;
11574 local64_set(&hwc->period_left, sample_period);
11577 child_event->ctx = child_ctx;
11578 child_event->overflow_handler = parent_event->overflow_handler;
11579 child_event->overflow_handler_context
11580 = parent_event->overflow_handler_context;
11583 * Precalculate sample_data sizes
11585 perf_event__header_size(child_event);
11586 perf_event__id_header_size(child_event);
11589 * Link it up in the child's context:
11591 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11592 add_event_to_ctx(child_event, child_ctx);
11593 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11596 * Link this into the parent event's child list
11598 list_add_tail(&child_event->child_list, &parent_event->child_list);
11599 mutex_unlock(&parent_event->child_mutex);
11601 return child_event;
11605 * Inherits an event group.
11607 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11608 * This matches with perf_event_release_kernel() removing all child events.
11614 static int inherit_group(struct perf_event *parent_event,
11615 struct task_struct *parent,
11616 struct perf_event_context *parent_ctx,
11617 struct task_struct *child,
11618 struct perf_event_context *child_ctx)
11620 struct perf_event *leader;
11621 struct perf_event *sub;
11622 struct perf_event *child_ctr;
11624 leader = inherit_event(parent_event, parent, parent_ctx,
11625 child, NULL, child_ctx);
11626 if (IS_ERR(leader))
11627 return PTR_ERR(leader);
11629 * @leader can be NULL here because of is_orphaned_event(). In this
11630 * case inherit_event() will create individual events, similar to what
11631 * perf_group_detach() would do anyway.
11633 for_each_sibling_event(sub, parent_event) {
11634 child_ctr = inherit_event(sub, parent, parent_ctx,
11635 child, leader, child_ctx);
11636 if (IS_ERR(child_ctr))
11637 return PTR_ERR(child_ctr);
11643 * Creates the child task context and tries to inherit the event-group.
11645 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11646 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11647 * consistent with perf_event_release_kernel() removing all child events.
11654 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11655 struct perf_event_context *parent_ctx,
11656 struct task_struct *child, int ctxn,
11657 int *inherited_all)
11660 struct perf_event_context *child_ctx;
11662 if (!event->attr.inherit) {
11663 *inherited_all = 0;
11667 child_ctx = child->perf_event_ctxp[ctxn];
11670 * This is executed from the parent task context, so
11671 * inherit events that have been marked for cloning.
11672 * First allocate and initialize a context for the
11675 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11679 child->perf_event_ctxp[ctxn] = child_ctx;
11682 ret = inherit_group(event, parent, parent_ctx,
11686 *inherited_all = 0;
11692 * Initialize the perf_event context in task_struct
11694 static int perf_event_init_context(struct task_struct *child, int ctxn)
11696 struct perf_event_context *child_ctx, *parent_ctx;
11697 struct perf_event_context *cloned_ctx;
11698 struct perf_event *event;
11699 struct task_struct *parent = current;
11700 int inherited_all = 1;
11701 unsigned long flags;
11704 if (likely(!parent->perf_event_ctxp[ctxn]))
11708 * If the parent's context is a clone, pin it so it won't get
11709 * swapped under us.
11711 parent_ctx = perf_pin_task_context(parent, ctxn);
11716 * No need to check if parent_ctx != NULL here; since we saw
11717 * it non-NULL earlier, the only reason for it to become NULL
11718 * is if we exit, and since we're currently in the middle of
11719 * a fork we can't be exiting at the same time.
11723 * Lock the parent list. No need to lock the child - not PID
11724 * hashed yet and not running, so nobody can access it.
11726 mutex_lock(&parent_ctx->mutex);
11729 * We dont have to disable NMIs - we are only looking at
11730 * the list, not manipulating it:
11732 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11733 ret = inherit_task_group(event, parent, parent_ctx,
11734 child, ctxn, &inherited_all);
11740 * We can't hold ctx->lock when iterating the ->flexible_group list due
11741 * to allocations, but we need to prevent rotation because
11742 * rotate_ctx() will change the list from interrupt context.
11744 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11745 parent_ctx->rotate_disable = 1;
11746 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11748 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11749 ret = inherit_task_group(event, parent, parent_ctx,
11750 child, ctxn, &inherited_all);
11755 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11756 parent_ctx->rotate_disable = 0;
11758 child_ctx = child->perf_event_ctxp[ctxn];
11760 if (child_ctx && inherited_all) {
11762 * Mark the child context as a clone of the parent
11763 * context, or of whatever the parent is a clone of.
11765 * Note that if the parent is a clone, the holding of
11766 * parent_ctx->lock avoids it from being uncloned.
11768 cloned_ctx = parent_ctx->parent_ctx;
11770 child_ctx->parent_ctx = cloned_ctx;
11771 child_ctx->parent_gen = parent_ctx->parent_gen;
11773 child_ctx->parent_ctx = parent_ctx;
11774 child_ctx->parent_gen = parent_ctx->generation;
11776 get_ctx(child_ctx->parent_ctx);
11779 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11781 mutex_unlock(&parent_ctx->mutex);
11783 perf_unpin_context(parent_ctx);
11784 put_ctx(parent_ctx);
11790 * Initialize the perf_event context in task_struct
11792 int perf_event_init_task(struct task_struct *child)
11796 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11797 mutex_init(&child->perf_event_mutex);
11798 INIT_LIST_HEAD(&child->perf_event_list);
11800 for_each_task_context_nr(ctxn) {
11801 ret = perf_event_init_context(child, ctxn);
11803 perf_event_free_task(child);
11811 static void __init perf_event_init_all_cpus(void)
11813 struct swevent_htable *swhash;
11816 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11818 for_each_possible_cpu(cpu) {
11819 swhash = &per_cpu(swevent_htable, cpu);
11820 mutex_init(&swhash->hlist_mutex);
11821 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11823 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11824 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11826 #ifdef CONFIG_CGROUP_PERF
11827 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11829 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11833 void perf_swevent_init_cpu(unsigned int cpu)
11835 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11837 mutex_lock(&swhash->hlist_mutex);
11838 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11839 struct swevent_hlist *hlist;
11841 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11843 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11845 mutex_unlock(&swhash->hlist_mutex);
11848 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11849 static void __perf_event_exit_context(void *__info)
11851 struct perf_event_context *ctx = __info;
11852 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11853 struct perf_event *event;
11855 raw_spin_lock(&ctx->lock);
11856 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11857 list_for_each_entry(event, &ctx->event_list, event_entry)
11858 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11859 raw_spin_unlock(&ctx->lock);
11862 static void perf_event_exit_cpu_context(int cpu)
11864 struct perf_cpu_context *cpuctx;
11865 struct perf_event_context *ctx;
11868 mutex_lock(&pmus_lock);
11869 list_for_each_entry(pmu, &pmus, entry) {
11870 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11871 ctx = &cpuctx->ctx;
11873 mutex_lock(&ctx->mutex);
11874 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11875 cpuctx->online = 0;
11876 mutex_unlock(&ctx->mutex);
11878 cpumask_clear_cpu(cpu, perf_online_mask);
11879 mutex_unlock(&pmus_lock);
11883 static void perf_event_exit_cpu_context(int cpu) { }
11887 int perf_event_init_cpu(unsigned int cpu)
11889 struct perf_cpu_context *cpuctx;
11890 struct perf_event_context *ctx;
11893 perf_swevent_init_cpu(cpu);
11895 mutex_lock(&pmus_lock);
11896 cpumask_set_cpu(cpu, perf_online_mask);
11897 list_for_each_entry(pmu, &pmus, entry) {
11898 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11899 ctx = &cpuctx->ctx;
11901 mutex_lock(&ctx->mutex);
11902 cpuctx->online = 1;
11903 mutex_unlock(&ctx->mutex);
11905 mutex_unlock(&pmus_lock);
11910 int perf_event_exit_cpu(unsigned int cpu)
11912 perf_event_exit_cpu_context(cpu);
11917 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11921 for_each_online_cpu(cpu)
11922 perf_event_exit_cpu(cpu);
11928 * Run the perf reboot notifier at the very last possible moment so that
11929 * the generic watchdog code runs as long as possible.
11931 static struct notifier_block perf_reboot_notifier = {
11932 .notifier_call = perf_reboot,
11933 .priority = INT_MIN,
11936 void __init perf_event_init(void)
11940 idr_init(&pmu_idr);
11942 perf_event_init_all_cpus();
11943 init_srcu_struct(&pmus_srcu);
11944 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11945 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11946 perf_pmu_register(&perf_task_clock, NULL, -1);
11947 perf_tp_register();
11948 perf_event_init_cpu(smp_processor_id());
11949 register_reboot_notifier(&perf_reboot_notifier);
11951 ret = init_hw_breakpoint();
11952 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11955 * Build time assertion that we keep the data_head at the intended
11956 * location. IOW, validation we got the __reserved[] size right.
11958 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11962 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11965 struct perf_pmu_events_attr *pmu_attr =
11966 container_of(attr, struct perf_pmu_events_attr, attr);
11968 if (pmu_attr->event_str)
11969 return sprintf(page, "%s\n", pmu_attr->event_str);
11973 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11975 static int __init perf_event_sysfs_init(void)
11980 mutex_lock(&pmus_lock);
11982 ret = bus_register(&pmu_bus);
11986 list_for_each_entry(pmu, &pmus, entry) {
11987 if (!pmu->name || pmu->type < 0)
11990 ret = pmu_dev_alloc(pmu);
11991 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11993 pmu_bus_running = 1;
11997 mutex_unlock(&pmus_lock);
12001 device_initcall(perf_event_sysfs_init);
12003 #ifdef CONFIG_CGROUP_PERF
12004 static struct cgroup_subsys_state *
12005 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12007 struct perf_cgroup *jc;
12009 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12011 return ERR_PTR(-ENOMEM);
12013 jc->info = alloc_percpu(struct perf_cgroup_info);
12016 return ERR_PTR(-ENOMEM);
12022 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12024 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12026 free_percpu(jc->info);
12030 static int __perf_cgroup_move(void *info)
12032 struct task_struct *task = info;
12034 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12039 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12041 struct task_struct *task;
12042 struct cgroup_subsys_state *css;
12044 cgroup_taskset_for_each(task, css, tset)
12045 task_function_call(task, __perf_cgroup_move, task);
12048 struct cgroup_subsys perf_event_cgrp_subsys = {
12049 .css_alloc = perf_cgroup_css_alloc,
12050 .css_free = perf_cgroup_css_free,
12051 .attach = perf_cgroup_attach,
12053 * Implicitly enable on dfl hierarchy so that perf events can
12054 * always be filtered by cgroup2 path as long as perf_event
12055 * controller is not mounted on a legacy hierarchy.
12057 .implicit_on_dfl = true,
12060 #endif /* CONFIG_CGROUP_PERF */