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
1258 * perf_addr_filters_head::lock
1262 * cpuctx->mutex / perf_event_context::mutex
1264 static struct perf_event_context *
1265 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1267 struct perf_event_context *ctx;
1271 ctx = READ_ONCE(event->ctx);
1272 if (!refcount_inc_not_zero(&ctx->refcount)) {
1278 mutex_lock_nested(&ctx->mutex, nesting);
1279 if (event->ctx != ctx) {
1280 mutex_unlock(&ctx->mutex);
1288 static inline struct perf_event_context *
1289 perf_event_ctx_lock(struct perf_event *event)
1291 return perf_event_ctx_lock_nested(event, 0);
1294 static void perf_event_ctx_unlock(struct perf_event *event,
1295 struct perf_event_context *ctx)
1297 mutex_unlock(&ctx->mutex);
1302 * This must be done under the ctx->lock, such as to serialize against
1303 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1304 * calling scheduler related locks and ctx->lock nests inside those.
1306 static __must_check struct perf_event_context *
1307 unclone_ctx(struct perf_event_context *ctx)
1309 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1311 lockdep_assert_held(&ctx->lock);
1314 ctx->parent_ctx = NULL;
1320 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1325 * only top level events have the pid namespace they were created in
1328 event = event->parent;
1330 nr = __task_pid_nr_ns(p, type, event->ns);
1331 /* avoid -1 if it is idle thread or runs in another ns */
1332 if (!nr && !pid_alive(p))
1337 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1339 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1342 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1344 return perf_event_pid_type(event, p, PIDTYPE_PID);
1348 * If we inherit events we want to return the parent event id
1351 static u64 primary_event_id(struct perf_event *event)
1356 id = event->parent->id;
1362 * Get the perf_event_context for a task and lock it.
1364 * This has to cope with with the fact that until it is locked,
1365 * the context could get moved to another task.
1367 static struct perf_event_context *
1368 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1370 struct perf_event_context *ctx;
1374 * One of the few rules of preemptible RCU is that one cannot do
1375 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1376 * part of the read side critical section was irqs-enabled -- see
1377 * rcu_read_unlock_special().
1379 * Since ctx->lock nests under rq->lock we must ensure the entire read
1380 * side critical section has interrupts disabled.
1382 local_irq_save(*flags);
1384 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1387 * If this context is a clone of another, it might
1388 * get swapped for another underneath us by
1389 * perf_event_task_sched_out, though the
1390 * rcu_read_lock() protects us from any context
1391 * getting freed. Lock the context and check if it
1392 * got swapped before we could get the lock, and retry
1393 * if so. If we locked the right context, then it
1394 * can't get swapped on us any more.
1396 raw_spin_lock(&ctx->lock);
1397 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1398 raw_spin_unlock(&ctx->lock);
1400 local_irq_restore(*flags);
1404 if (ctx->task == TASK_TOMBSTONE ||
1405 !refcount_inc_not_zero(&ctx->refcount)) {
1406 raw_spin_unlock(&ctx->lock);
1409 WARN_ON_ONCE(ctx->task != task);
1414 local_irq_restore(*flags);
1419 * Get the context for a task and increment its pin_count so it
1420 * can't get swapped to another task. This also increments its
1421 * reference count so that the context can't get freed.
1423 static struct perf_event_context *
1424 perf_pin_task_context(struct task_struct *task, int ctxn)
1426 struct perf_event_context *ctx;
1427 unsigned long flags;
1429 ctx = perf_lock_task_context(task, ctxn, &flags);
1432 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1437 static void perf_unpin_context(struct perf_event_context *ctx)
1439 unsigned long flags;
1441 raw_spin_lock_irqsave(&ctx->lock, flags);
1443 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1447 * Update the record of the current time in a context.
1449 static void update_context_time(struct perf_event_context *ctx)
1451 u64 now = perf_clock();
1453 ctx->time += now - ctx->timestamp;
1454 ctx->timestamp = now;
1457 static u64 perf_event_time(struct perf_event *event)
1459 struct perf_event_context *ctx = event->ctx;
1461 if (is_cgroup_event(event))
1462 return perf_cgroup_event_time(event);
1464 return ctx ? ctx->time : 0;
1467 static enum event_type_t get_event_type(struct perf_event *event)
1469 struct perf_event_context *ctx = event->ctx;
1470 enum event_type_t event_type;
1472 lockdep_assert_held(&ctx->lock);
1475 * It's 'group type', really, because if our group leader is
1476 * pinned, so are we.
1478 if (event->group_leader != event)
1479 event = event->group_leader;
1481 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1483 event_type |= EVENT_CPU;
1489 * Helper function to initialize event group nodes.
1491 static void init_event_group(struct perf_event *event)
1493 RB_CLEAR_NODE(&event->group_node);
1494 event->group_index = 0;
1498 * Extract pinned or flexible groups from the context
1499 * based on event attrs bits.
1501 static struct perf_event_groups *
1502 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1504 if (event->attr.pinned)
1505 return &ctx->pinned_groups;
1507 return &ctx->flexible_groups;
1511 * Helper function to initializes perf_event_group trees.
1513 static void perf_event_groups_init(struct perf_event_groups *groups)
1515 groups->tree = RB_ROOT;
1520 * Compare function for event groups;
1522 * Implements complex key that first sorts by CPU and then by virtual index
1523 * which provides ordering when rotating groups for the same CPU.
1526 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1528 if (left->cpu < right->cpu)
1530 if (left->cpu > right->cpu)
1533 if (left->group_index < right->group_index)
1535 if (left->group_index > right->group_index)
1542 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1543 * key (see perf_event_groups_less). This places it last inside the CPU
1547 perf_event_groups_insert(struct perf_event_groups *groups,
1548 struct perf_event *event)
1550 struct perf_event *node_event;
1551 struct rb_node *parent;
1552 struct rb_node **node;
1554 event->group_index = ++groups->index;
1556 node = &groups->tree.rb_node;
1561 node_event = container_of(*node, struct perf_event, group_node);
1563 if (perf_event_groups_less(event, node_event))
1564 node = &parent->rb_left;
1566 node = &parent->rb_right;
1569 rb_link_node(&event->group_node, parent, node);
1570 rb_insert_color(&event->group_node, &groups->tree);
1574 * Helper function to insert event into the pinned or flexible groups.
1577 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1579 struct perf_event_groups *groups;
1581 groups = get_event_groups(event, ctx);
1582 perf_event_groups_insert(groups, event);
1586 * Delete a group from a tree.
1589 perf_event_groups_delete(struct perf_event_groups *groups,
1590 struct perf_event *event)
1592 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1593 RB_EMPTY_ROOT(&groups->tree));
1595 rb_erase(&event->group_node, &groups->tree);
1596 init_event_group(event);
1600 * Helper function to delete event from its groups.
1603 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1605 struct perf_event_groups *groups;
1607 groups = get_event_groups(event, ctx);
1608 perf_event_groups_delete(groups, event);
1612 * Get the leftmost event in the @cpu subtree.
1614 static struct perf_event *
1615 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1617 struct perf_event *node_event = NULL, *match = NULL;
1618 struct rb_node *node = groups->tree.rb_node;
1621 node_event = container_of(node, struct perf_event, group_node);
1623 if (cpu < node_event->cpu) {
1624 node = node->rb_left;
1625 } else if (cpu > node_event->cpu) {
1626 node = node->rb_right;
1629 node = node->rb_left;
1637 * Like rb_entry_next_safe() for the @cpu subtree.
1639 static struct perf_event *
1640 perf_event_groups_next(struct perf_event *event)
1642 struct perf_event *next;
1644 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1645 if (next && next->cpu == event->cpu)
1652 * Iterate through the whole groups tree.
1654 #define perf_event_groups_for_each(event, groups) \
1655 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1656 typeof(*event), group_node); event; \
1657 event = rb_entry_safe(rb_next(&event->group_node), \
1658 typeof(*event), group_node))
1661 * Add an event from the lists for its context.
1662 * Must be called with ctx->mutex and ctx->lock held.
1665 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1667 lockdep_assert_held(&ctx->lock);
1669 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1670 event->attach_state |= PERF_ATTACH_CONTEXT;
1672 event->tstamp = perf_event_time(event);
1675 * If we're a stand alone event or group leader, we go to the context
1676 * list, group events are kept attached to the group so that
1677 * perf_group_detach can, at all times, locate all siblings.
1679 if (event->group_leader == event) {
1680 event->group_caps = event->event_caps;
1681 add_event_to_groups(event, ctx);
1684 list_update_cgroup_event(event, ctx, true);
1686 list_add_rcu(&event->event_entry, &ctx->event_list);
1688 if (event->attr.inherit_stat)
1695 * Initialize event state based on the perf_event_attr::disabled.
1697 static inline void perf_event__state_init(struct perf_event *event)
1699 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1700 PERF_EVENT_STATE_INACTIVE;
1703 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1705 int entry = sizeof(u64); /* value */
1709 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1710 size += sizeof(u64);
1712 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1713 size += sizeof(u64);
1715 if (event->attr.read_format & PERF_FORMAT_ID)
1716 entry += sizeof(u64);
1718 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1720 size += sizeof(u64);
1724 event->read_size = size;
1727 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1729 struct perf_sample_data *data;
1732 if (sample_type & PERF_SAMPLE_IP)
1733 size += sizeof(data->ip);
1735 if (sample_type & PERF_SAMPLE_ADDR)
1736 size += sizeof(data->addr);
1738 if (sample_type & PERF_SAMPLE_PERIOD)
1739 size += sizeof(data->period);
1741 if (sample_type & PERF_SAMPLE_WEIGHT)
1742 size += sizeof(data->weight);
1744 if (sample_type & PERF_SAMPLE_READ)
1745 size += event->read_size;
1747 if (sample_type & PERF_SAMPLE_DATA_SRC)
1748 size += sizeof(data->data_src.val);
1750 if (sample_type & PERF_SAMPLE_TRANSACTION)
1751 size += sizeof(data->txn);
1753 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1754 size += sizeof(data->phys_addr);
1756 event->header_size = size;
1760 * Called at perf_event creation and when events are attached/detached from a
1763 static void perf_event__header_size(struct perf_event *event)
1765 __perf_event_read_size(event,
1766 event->group_leader->nr_siblings);
1767 __perf_event_header_size(event, event->attr.sample_type);
1770 static void perf_event__id_header_size(struct perf_event *event)
1772 struct perf_sample_data *data;
1773 u64 sample_type = event->attr.sample_type;
1776 if (sample_type & PERF_SAMPLE_TID)
1777 size += sizeof(data->tid_entry);
1779 if (sample_type & PERF_SAMPLE_TIME)
1780 size += sizeof(data->time);
1782 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1783 size += sizeof(data->id);
1785 if (sample_type & PERF_SAMPLE_ID)
1786 size += sizeof(data->id);
1788 if (sample_type & PERF_SAMPLE_STREAM_ID)
1789 size += sizeof(data->stream_id);
1791 if (sample_type & PERF_SAMPLE_CPU)
1792 size += sizeof(data->cpu_entry);
1794 event->id_header_size = size;
1797 static bool perf_event_validate_size(struct perf_event *event)
1800 * The values computed here will be over-written when we actually
1803 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1804 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1805 perf_event__id_header_size(event);
1808 * Sum the lot; should not exceed the 64k limit we have on records.
1809 * Conservative limit to allow for callchains and other variable fields.
1811 if (event->read_size + event->header_size +
1812 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1818 static void perf_group_attach(struct perf_event *event)
1820 struct perf_event *group_leader = event->group_leader, *pos;
1822 lockdep_assert_held(&event->ctx->lock);
1825 * We can have double attach due to group movement in perf_event_open.
1827 if (event->attach_state & PERF_ATTACH_GROUP)
1830 event->attach_state |= PERF_ATTACH_GROUP;
1832 if (group_leader == event)
1835 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1837 group_leader->group_caps &= event->event_caps;
1839 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1840 group_leader->nr_siblings++;
1842 perf_event__header_size(group_leader);
1844 for_each_sibling_event(pos, group_leader)
1845 perf_event__header_size(pos);
1849 * Remove an event from the lists for its context.
1850 * Must be called with ctx->mutex and ctx->lock held.
1853 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1855 WARN_ON_ONCE(event->ctx != ctx);
1856 lockdep_assert_held(&ctx->lock);
1859 * We can have double detach due to exit/hot-unplug + close.
1861 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1864 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1866 list_update_cgroup_event(event, ctx, false);
1869 if (event->attr.inherit_stat)
1872 list_del_rcu(&event->event_entry);
1874 if (event->group_leader == event)
1875 del_event_from_groups(event, ctx);
1878 * If event was in error state, then keep it
1879 * that way, otherwise bogus counts will be
1880 * returned on read(). The only way to get out
1881 * of error state is by explicit re-enabling
1884 if (event->state > PERF_EVENT_STATE_OFF)
1885 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1890 static void perf_group_detach(struct perf_event *event)
1892 struct perf_event *sibling, *tmp;
1893 struct perf_event_context *ctx = event->ctx;
1895 lockdep_assert_held(&ctx->lock);
1898 * We can have double detach due to exit/hot-unplug + close.
1900 if (!(event->attach_state & PERF_ATTACH_GROUP))
1903 event->attach_state &= ~PERF_ATTACH_GROUP;
1906 * If this is a sibling, remove it from its group.
1908 if (event->group_leader != event) {
1909 list_del_init(&event->sibling_list);
1910 event->group_leader->nr_siblings--;
1915 * If this was a group event with sibling events then
1916 * upgrade the siblings to singleton events by adding them
1917 * to whatever list we are on.
1919 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1921 sibling->group_leader = sibling;
1922 list_del_init(&sibling->sibling_list);
1924 /* Inherit group flags from the previous leader */
1925 sibling->group_caps = event->group_caps;
1927 if (!RB_EMPTY_NODE(&event->group_node)) {
1928 add_event_to_groups(sibling, event->ctx);
1930 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1931 struct list_head *list = sibling->attr.pinned ?
1932 &ctx->pinned_active : &ctx->flexible_active;
1934 list_add_tail(&sibling->active_list, list);
1938 WARN_ON_ONCE(sibling->ctx != event->ctx);
1942 perf_event__header_size(event->group_leader);
1944 for_each_sibling_event(tmp, event->group_leader)
1945 perf_event__header_size(tmp);
1948 static bool is_orphaned_event(struct perf_event *event)
1950 return event->state == PERF_EVENT_STATE_DEAD;
1953 static inline int __pmu_filter_match(struct perf_event *event)
1955 struct pmu *pmu = event->pmu;
1956 return pmu->filter_match ? pmu->filter_match(event) : 1;
1960 * Check whether we should attempt to schedule an event group based on
1961 * PMU-specific filtering. An event group can consist of HW and SW events,
1962 * potentially with a SW leader, so we must check all the filters, to
1963 * determine whether a group is schedulable:
1965 static inline int pmu_filter_match(struct perf_event *event)
1967 struct perf_event *sibling;
1969 if (!__pmu_filter_match(event))
1972 for_each_sibling_event(sibling, event) {
1973 if (!__pmu_filter_match(sibling))
1981 event_filter_match(struct perf_event *event)
1983 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1984 perf_cgroup_match(event) && pmu_filter_match(event);
1988 event_sched_out(struct perf_event *event,
1989 struct perf_cpu_context *cpuctx,
1990 struct perf_event_context *ctx)
1992 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1994 WARN_ON_ONCE(event->ctx != ctx);
1995 lockdep_assert_held(&ctx->lock);
1997 if (event->state != PERF_EVENT_STATE_ACTIVE)
2001 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2002 * we can schedule events _OUT_ individually through things like
2003 * __perf_remove_from_context().
2005 list_del_init(&event->active_list);
2007 perf_pmu_disable(event->pmu);
2009 event->pmu->del(event, 0);
2012 if (event->pending_disable) {
2013 event->pending_disable = 0;
2014 state = PERF_EVENT_STATE_OFF;
2016 perf_event_set_state(event, state);
2018 if (!is_software_event(event))
2019 cpuctx->active_oncpu--;
2020 if (!--ctx->nr_active)
2021 perf_event_ctx_deactivate(ctx);
2022 if (event->attr.freq && event->attr.sample_freq)
2024 if (event->attr.exclusive || !cpuctx->active_oncpu)
2025 cpuctx->exclusive = 0;
2027 perf_pmu_enable(event->pmu);
2031 group_sched_out(struct perf_event *group_event,
2032 struct perf_cpu_context *cpuctx,
2033 struct perf_event_context *ctx)
2035 struct perf_event *event;
2037 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2040 perf_pmu_disable(ctx->pmu);
2042 event_sched_out(group_event, cpuctx, ctx);
2045 * Schedule out siblings (if any):
2047 for_each_sibling_event(event, group_event)
2048 event_sched_out(event, cpuctx, ctx);
2050 perf_pmu_enable(ctx->pmu);
2052 if (group_event->attr.exclusive)
2053 cpuctx->exclusive = 0;
2056 #define DETACH_GROUP 0x01UL
2059 * Cross CPU call to remove a performance event
2061 * We disable the event on the hardware level first. After that we
2062 * remove it from the context list.
2065 __perf_remove_from_context(struct perf_event *event,
2066 struct perf_cpu_context *cpuctx,
2067 struct perf_event_context *ctx,
2070 unsigned long flags = (unsigned long)info;
2072 if (ctx->is_active & EVENT_TIME) {
2073 update_context_time(ctx);
2074 update_cgrp_time_from_cpuctx(cpuctx);
2077 event_sched_out(event, cpuctx, ctx);
2078 if (flags & DETACH_GROUP)
2079 perf_group_detach(event);
2080 list_del_event(event, ctx);
2082 if (!ctx->nr_events && ctx->is_active) {
2085 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2086 cpuctx->task_ctx = NULL;
2092 * Remove the event from a task's (or a CPU's) list of events.
2094 * If event->ctx is a cloned context, callers must make sure that
2095 * every task struct that event->ctx->task could possibly point to
2096 * remains valid. This is OK when called from perf_release since
2097 * that only calls us on the top-level context, which can't be a clone.
2098 * When called from perf_event_exit_task, it's OK because the
2099 * context has been detached from its task.
2101 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2103 struct perf_event_context *ctx = event->ctx;
2105 lockdep_assert_held(&ctx->mutex);
2107 event_function_call(event, __perf_remove_from_context, (void *)flags);
2110 * The above event_function_call() can NO-OP when it hits
2111 * TASK_TOMBSTONE. In that case we must already have been detached
2112 * from the context (by perf_event_exit_event()) but the grouping
2113 * might still be in-tact.
2115 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2116 if ((flags & DETACH_GROUP) &&
2117 (event->attach_state & PERF_ATTACH_GROUP)) {
2119 * Since in that case we cannot possibly be scheduled, simply
2122 raw_spin_lock_irq(&ctx->lock);
2123 perf_group_detach(event);
2124 raw_spin_unlock_irq(&ctx->lock);
2129 * Cross CPU call to disable a performance event
2131 static void __perf_event_disable(struct perf_event *event,
2132 struct perf_cpu_context *cpuctx,
2133 struct perf_event_context *ctx,
2136 if (event->state < PERF_EVENT_STATE_INACTIVE)
2139 if (ctx->is_active & EVENT_TIME) {
2140 update_context_time(ctx);
2141 update_cgrp_time_from_event(event);
2144 if (event == event->group_leader)
2145 group_sched_out(event, cpuctx, ctx);
2147 event_sched_out(event, cpuctx, ctx);
2149 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2155 * If event->ctx is a cloned context, callers must make sure that
2156 * every task struct that event->ctx->task could possibly point to
2157 * remains valid. This condition is satisifed when called through
2158 * perf_event_for_each_child or perf_event_for_each because they
2159 * hold the top-level event's child_mutex, so any descendant that
2160 * goes to exit will block in perf_event_exit_event().
2162 * When called from perf_pending_event it's OK because event->ctx
2163 * is the current context on this CPU and preemption is disabled,
2164 * hence we can't get into perf_event_task_sched_out for this context.
2166 static void _perf_event_disable(struct perf_event *event)
2168 struct perf_event_context *ctx = event->ctx;
2170 raw_spin_lock_irq(&ctx->lock);
2171 if (event->state <= PERF_EVENT_STATE_OFF) {
2172 raw_spin_unlock_irq(&ctx->lock);
2175 raw_spin_unlock_irq(&ctx->lock);
2177 event_function_call(event, __perf_event_disable, NULL);
2180 void perf_event_disable_local(struct perf_event *event)
2182 event_function_local(event, __perf_event_disable, NULL);
2186 * Strictly speaking kernel users cannot create groups and therefore this
2187 * interface does not need the perf_event_ctx_lock() magic.
2189 void perf_event_disable(struct perf_event *event)
2191 struct perf_event_context *ctx;
2193 ctx = perf_event_ctx_lock(event);
2194 _perf_event_disable(event);
2195 perf_event_ctx_unlock(event, ctx);
2197 EXPORT_SYMBOL_GPL(perf_event_disable);
2199 void perf_event_disable_inatomic(struct perf_event *event)
2201 event->pending_disable = 1;
2202 irq_work_queue(&event->pending);
2205 static void perf_set_shadow_time(struct perf_event *event,
2206 struct perf_event_context *ctx)
2209 * use the correct time source for the time snapshot
2211 * We could get by without this by leveraging the
2212 * fact that to get to this function, the caller
2213 * has most likely already called update_context_time()
2214 * and update_cgrp_time_xx() and thus both timestamp
2215 * are identical (or very close). Given that tstamp is,
2216 * already adjusted for cgroup, we could say that:
2217 * tstamp - ctx->timestamp
2219 * tstamp - cgrp->timestamp.
2221 * Then, in perf_output_read(), the calculation would
2222 * work with no changes because:
2223 * - event is guaranteed scheduled in
2224 * - no scheduled out in between
2225 * - thus the timestamp would be the same
2227 * But this is a bit hairy.
2229 * So instead, we have an explicit cgroup call to remain
2230 * within the time time source all along. We believe it
2231 * is cleaner and simpler to understand.
2233 if (is_cgroup_event(event))
2234 perf_cgroup_set_shadow_time(event, event->tstamp);
2236 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2239 #define MAX_INTERRUPTS (~0ULL)
2241 static void perf_log_throttle(struct perf_event *event, int enable);
2242 static void perf_log_itrace_start(struct perf_event *event);
2245 event_sched_in(struct perf_event *event,
2246 struct perf_cpu_context *cpuctx,
2247 struct perf_event_context *ctx)
2251 lockdep_assert_held(&ctx->lock);
2253 if (event->state <= PERF_EVENT_STATE_OFF)
2256 WRITE_ONCE(event->oncpu, smp_processor_id());
2258 * Order event::oncpu write to happen before the ACTIVE state is
2259 * visible. This allows perf_event_{stop,read}() to observe the correct
2260 * ->oncpu if it sees ACTIVE.
2263 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2266 * Unthrottle events, since we scheduled we might have missed several
2267 * ticks already, also for a heavily scheduling task there is little
2268 * guarantee it'll get a tick in a timely manner.
2270 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2271 perf_log_throttle(event, 1);
2272 event->hw.interrupts = 0;
2275 perf_pmu_disable(event->pmu);
2277 perf_set_shadow_time(event, ctx);
2279 perf_log_itrace_start(event);
2281 if (event->pmu->add(event, PERF_EF_START)) {
2282 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2288 if (!is_software_event(event))
2289 cpuctx->active_oncpu++;
2290 if (!ctx->nr_active++)
2291 perf_event_ctx_activate(ctx);
2292 if (event->attr.freq && event->attr.sample_freq)
2295 if (event->attr.exclusive)
2296 cpuctx->exclusive = 1;
2299 perf_pmu_enable(event->pmu);
2305 group_sched_in(struct perf_event *group_event,
2306 struct perf_cpu_context *cpuctx,
2307 struct perf_event_context *ctx)
2309 struct perf_event *event, *partial_group = NULL;
2310 struct pmu *pmu = ctx->pmu;
2312 if (group_event->state == PERF_EVENT_STATE_OFF)
2315 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2317 if (event_sched_in(group_event, cpuctx, ctx)) {
2318 pmu->cancel_txn(pmu);
2319 perf_mux_hrtimer_restart(cpuctx);
2324 * Schedule in siblings as one group (if any):
2326 for_each_sibling_event(event, group_event) {
2327 if (event_sched_in(event, cpuctx, ctx)) {
2328 partial_group = event;
2333 if (!pmu->commit_txn(pmu))
2338 * Groups can be scheduled in as one unit only, so undo any
2339 * partial group before returning:
2340 * The events up to the failed event are scheduled out normally.
2342 for_each_sibling_event(event, group_event) {
2343 if (event == partial_group)
2346 event_sched_out(event, cpuctx, ctx);
2348 event_sched_out(group_event, cpuctx, ctx);
2350 pmu->cancel_txn(pmu);
2352 perf_mux_hrtimer_restart(cpuctx);
2358 * Work out whether we can put this event group on the CPU now.
2360 static int group_can_go_on(struct perf_event *event,
2361 struct perf_cpu_context *cpuctx,
2365 * Groups consisting entirely of software events can always go on.
2367 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2370 * If an exclusive group is already on, no other hardware
2373 if (cpuctx->exclusive)
2376 * If this group is exclusive and there are already
2377 * events on the CPU, it can't go on.
2379 if (event->attr.exclusive && cpuctx->active_oncpu)
2382 * Otherwise, try to add it if all previous groups were able
2388 static void add_event_to_ctx(struct perf_event *event,
2389 struct perf_event_context *ctx)
2391 list_add_event(event, ctx);
2392 perf_group_attach(event);
2395 static void ctx_sched_out(struct perf_event_context *ctx,
2396 struct perf_cpu_context *cpuctx,
2397 enum event_type_t event_type);
2399 ctx_sched_in(struct perf_event_context *ctx,
2400 struct perf_cpu_context *cpuctx,
2401 enum event_type_t event_type,
2402 struct task_struct *task);
2404 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2405 struct perf_event_context *ctx,
2406 enum event_type_t event_type)
2408 if (!cpuctx->task_ctx)
2411 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2414 ctx_sched_out(ctx, cpuctx, event_type);
2417 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2418 struct perf_event_context *ctx,
2419 struct task_struct *task)
2421 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2423 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2424 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2426 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2430 * We want to maintain the following priority of scheduling:
2431 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2432 * - task pinned (EVENT_PINNED)
2433 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2434 * - task flexible (EVENT_FLEXIBLE).
2436 * In order to avoid unscheduling and scheduling back in everything every
2437 * time an event is added, only do it for the groups of equal priority and
2440 * This can be called after a batch operation on task events, in which case
2441 * event_type is a bit mask of the types of events involved. For CPU events,
2442 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2444 static void ctx_resched(struct perf_cpu_context *cpuctx,
2445 struct perf_event_context *task_ctx,
2446 enum event_type_t event_type)
2448 enum event_type_t ctx_event_type;
2449 bool cpu_event = !!(event_type & EVENT_CPU);
2452 * If pinned groups are involved, flexible groups also need to be
2455 if (event_type & EVENT_PINNED)
2456 event_type |= EVENT_FLEXIBLE;
2458 ctx_event_type = event_type & EVENT_ALL;
2460 perf_pmu_disable(cpuctx->ctx.pmu);
2462 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2465 * Decide which cpu ctx groups to schedule out based on the types
2466 * of events that caused rescheduling:
2467 * - EVENT_CPU: schedule out corresponding groups;
2468 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2469 * - otherwise, do nothing more.
2472 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2473 else if (ctx_event_type & EVENT_PINNED)
2474 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2476 perf_event_sched_in(cpuctx, task_ctx, current);
2477 perf_pmu_enable(cpuctx->ctx.pmu);
2481 * Cross CPU call to install and enable a performance event
2483 * Very similar to remote_function() + event_function() but cannot assume that
2484 * things like ctx->is_active and cpuctx->task_ctx are set.
2486 static int __perf_install_in_context(void *info)
2488 struct perf_event *event = info;
2489 struct perf_event_context *ctx = event->ctx;
2490 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2491 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2492 bool reprogram = true;
2495 raw_spin_lock(&cpuctx->ctx.lock);
2497 raw_spin_lock(&ctx->lock);
2500 reprogram = (ctx->task == current);
2503 * If the task is running, it must be running on this CPU,
2504 * otherwise we cannot reprogram things.
2506 * If its not running, we don't care, ctx->lock will
2507 * serialize against it becoming runnable.
2509 if (task_curr(ctx->task) && !reprogram) {
2514 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2515 } else if (task_ctx) {
2516 raw_spin_lock(&task_ctx->lock);
2519 #ifdef CONFIG_CGROUP_PERF
2520 if (is_cgroup_event(event)) {
2522 * If the current cgroup doesn't match the event's
2523 * cgroup, we should not try to schedule it.
2525 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2526 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2527 event->cgrp->css.cgroup);
2532 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2533 add_event_to_ctx(event, ctx);
2534 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2536 add_event_to_ctx(event, ctx);
2540 perf_ctx_unlock(cpuctx, task_ctx);
2546 * Attach a performance event to a context.
2548 * Very similar to event_function_call, see comment there.
2551 perf_install_in_context(struct perf_event_context *ctx,
2552 struct perf_event *event,
2555 struct task_struct *task = READ_ONCE(ctx->task);
2557 lockdep_assert_held(&ctx->mutex);
2559 if (event->cpu != -1)
2563 * Ensures that if we can observe event->ctx, both the event and ctx
2564 * will be 'complete'. See perf_iterate_sb_cpu().
2566 smp_store_release(&event->ctx, ctx);
2569 cpu_function_call(cpu, __perf_install_in_context, event);
2574 * Should not happen, we validate the ctx is still alive before calling.
2576 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2580 * Installing events is tricky because we cannot rely on ctx->is_active
2581 * to be set in case this is the nr_events 0 -> 1 transition.
2583 * Instead we use task_curr(), which tells us if the task is running.
2584 * However, since we use task_curr() outside of rq::lock, we can race
2585 * against the actual state. This means the result can be wrong.
2587 * If we get a false positive, we retry, this is harmless.
2589 * If we get a false negative, things are complicated. If we are after
2590 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2591 * value must be correct. If we're before, it doesn't matter since
2592 * perf_event_context_sched_in() will program the counter.
2594 * However, this hinges on the remote context switch having observed
2595 * our task->perf_event_ctxp[] store, such that it will in fact take
2596 * ctx::lock in perf_event_context_sched_in().
2598 * We do this by task_function_call(), if the IPI fails to hit the task
2599 * we know any future context switch of task must see the
2600 * perf_event_ctpx[] store.
2604 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2605 * task_cpu() load, such that if the IPI then does not find the task
2606 * running, a future context switch of that task must observe the
2611 if (!task_function_call(task, __perf_install_in_context, event))
2614 raw_spin_lock_irq(&ctx->lock);
2616 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2618 * Cannot happen because we already checked above (which also
2619 * cannot happen), and we hold ctx->mutex, which serializes us
2620 * against perf_event_exit_task_context().
2622 raw_spin_unlock_irq(&ctx->lock);
2626 * If the task is not running, ctx->lock will avoid it becoming so,
2627 * thus we can safely install the event.
2629 if (task_curr(task)) {
2630 raw_spin_unlock_irq(&ctx->lock);
2633 add_event_to_ctx(event, ctx);
2634 raw_spin_unlock_irq(&ctx->lock);
2638 * Cross CPU call to enable a performance event
2640 static void __perf_event_enable(struct perf_event *event,
2641 struct perf_cpu_context *cpuctx,
2642 struct perf_event_context *ctx,
2645 struct perf_event *leader = event->group_leader;
2646 struct perf_event_context *task_ctx;
2648 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2649 event->state <= PERF_EVENT_STATE_ERROR)
2653 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2655 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2657 if (!ctx->is_active)
2660 if (!event_filter_match(event)) {
2661 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2666 * If the event is in a group and isn't the group leader,
2667 * then don't put it on unless the group is on.
2669 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2670 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2674 task_ctx = cpuctx->task_ctx;
2676 WARN_ON_ONCE(task_ctx != ctx);
2678 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2684 * If event->ctx is a cloned context, callers must make sure that
2685 * every task struct that event->ctx->task could possibly point to
2686 * remains valid. This condition is satisfied when called through
2687 * perf_event_for_each_child or perf_event_for_each as described
2688 * for perf_event_disable.
2690 static void _perf_event_enable(struct perf_event *event)
2692 struct perf_event_context *ctx = event->ctx;
2694 raw_spin_lock_irq(&ctx->lock);
2695 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2696 event->state < PERF_EVENT_STATE_ERROR) {
2697 raw_spin_unlock_irq(&ctx->lock);
2702 * If the event is in error state, clear that first.
2704 * That way, if we see the event in error state below, we know that it
2705 * has gone back into error state, as distinct from the task having
2706 * been scheduled away before the cross-call arrived.
2708 if (event->state == PERF_EVENT_STATE_ERROR)
2709 event->state = PERF_EVENT_STATE_OFF;
2710 raw_spin_unlock_irq(&ctx->lock);
2712 event_function_call(event, __perf_event_enable, NULL);
2716 * See perf_event_disable();
2718 void perf_event_enable(struct perf_event *event)
2720 struct perf_event_context *ctx;
2722 ctx = perf_event_ctx_lock(event);
2723 _perf_event_enable(event);
2724 perf_event_ctx_unlock(event, ctx);
2726 EXPORT_SYMBOL_GPL(perf_event_enable);
2728 struct stop_event_data {
2729 struct perf_event *event;
2730 unsigned int restart;
2733 static int __perf_event_stop(void *info)
2735 struct stop_event_data *sd = info;
2736 struct perf_event *event = sd->event;
2738 /* if it's already INACTIVE, do nothing */
2739 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2742 /* matches smp_wmb() in event_sched_in() */
2746 * There is a window with interrupts enabled before we get here,
2747 * so we need to check again lest we try to stop another CPU's event.
2749 if (READ_ONCE(event->oncpu) != smp_processor_id())
2752 event->pmu->stop(event, PERF_EF_UPDATE);
2755 * May race with the actual stop (through perf_pmu_output_stop()),
2756 * but it is only used for events with AUX ring buffer, and such
2757 * events will refuse to restart because of rb::aux_mmap_count==0,
2758 * see comments in perf_aux_output_begin().
2760 * Since this is happening on an event-local CPU, no trace is lost
2764 event->pmu->start(event, 0);
2769 static int perf_event_stop(struct perf_event *event, int restart)
2771 struct stop_event_data sd = {
2778 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2781 /* matches smp_wmb() in event_sched_in() */
2785 * We only want to restart ACTIVE events, so if the event goes
2786 * inactive here (event->oncpu==-1), there's nothing more to do;
2787 * fall through with ret==-ENXIO.
2789 ret = cpu_function_call(READ_ONCE(event->oncpu),
2790 __perf_event_stop, &sd);
2791 } while (ret == -EAGAIN);
2797 * In order to contain the amount of racy and tricky in the address filter
2798 * configuration management, it is a two part process:
2800 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2801 * we update the addresses of corresponding vmas in
2802 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2803 * (p2) when an event is scheduled in (pmu::add), it calls
2804 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2805 * if the generation has changed since the previous call.
2807 * If (p1) happens while the event is active, we restart it to force (p2).
2809 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2810 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2812 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2813 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2815 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2818 void perf_event_addr_filters_sync(struct perf_event *event)
2820 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2822 if (!has_addr_filter(event))
2825 raw_spin_lock(&ifh->lock);
2826 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2827 event->pmu->addr_filters_sync(event);
2828 event->hw.addr_filters_gen = event->addr_filters_gen;
2830 raw_spin_unlock(&ifh->lock);
2832 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2834 static int _perf_event_refresh(struct perf_event *event, int refresh)
2837 * not supported on inherited events
2839 if (event->attr.inherit || !is_sampling_event(event))
2842 atomic_add(refresh, &event->event_limit);
2843 _perf_event_enable(event);
2849 * See perf_event_disable()
2851 int perf_event_refresh(struct perf_event *event, int refresh)
2853 struct perf_event_context *ctx;
2856 ctx = perf_event_ctx_lock(event);
2857 ret = _perf_event_refresh(event, refresh);
2858 perf_event_ctx_unlock(event, ctx);
2862 EXPORT_SYMBOL_GPL(perf_event_refresh);
2864 static int perf_event_modify_breakpoint(struct perf_event *bp,
2865 struct perf_event_attr *attr)
2869 _perf_event_disable(bp);
2871 err = modify_user_hw_breakpoint_check(bp, attr, true);
2873 if (!bp->attr.disabled)
2874 _perf_event_enable(bp);
2879 static int perf_event_modify_attr(struct perf_event *event,
2880 struct perf_event_attr *attr)
2882 if (event->attr.type != attr->type)
2885 switch (event->attr.type) {
2886 case PERF_TYPE_BREAKPOINT:
2887 return perf_event_modify_breakpoint(event, attr);
2889 /* Place holder for future additions. */
2894 static void ctx_sched_out(struct perf_event_context *ctx,
2895 struct perf_cpu_context *cpuctx,
2896 enum event_type_t event_type)
2898 struct perf_event *event, *tmp;
2899 int is_active = ctx->is_active;
2901 lockdep_assert_held(&ctx->lock);
2903 if (likely(!ctx->nr_events)) {
2905 * See __perf_remove_from_context().
2907 WARN_ON_ONCE(ctx->is_active);
2909 WARN_ON_ONCE(cpuctx->task_ctx);
2913 ctx->is_active &= ~event_type;
2914 if (!(ctx->is_active & EVENT_ALL))
2918 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2919 if (!ctx->is_active)
2920 cpuctx->task_ctx = NULL;
2924 * Always update time if it was set; not only when it changes.
2925 * Otherwise we can 'forget' to update time for any but the last
2926 * context we sched out. For example:
2928 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2929 * ctx_sched_out(.event_type = EVENT_PINNED)
2931 * would only update time for the pinned events.
2933 if (is_active & EVENT_TIME) {
2934 /* update (and stop) ctx time */
2935 update_context_time(ctx);
2936 update_cgrp_time_from_cpuctx(cpuctx);
2939 is_active ^= ctx->is_active; /* changed bits */
2941 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2944 perf_pmu_disable(ctx->pmu);
2945 if (is_active & EVENT_PINNED) {
2946 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2947 group_sched_out(event, cpuctx, ctx);
2950 if (is_active & EVENT_FLEXIBLE) {
2951 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2952 group_sched_out(event, cpuctx, ctx);
2954 perf_pmu_enable(ctx->pmu);
2958 * Test whether two contexts are equivalent, i.e. whether they have both been
2959 * cloned from the same version of the same context.
2961 * Equivalence is measured using a generation number in the context that is
2962 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2963 * and list_del_event().
2965 static int context_equiv(struct perf_event_context *ctx1,
2966 struct perf_event_context *ctx2)
2968 lockdep_assert_held(&ctx1->lock);
2969 lockdep_assert_held(&ctx2->lock);
2971 /* Pinning disables the swap optimization */
2972 if (ctx1->pin_count || ctx2->pin_count)
2975 /* If ctx1 is the parent of ctx2 */
2976 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2979 /* If ctx2 is the parent of ctx1 */
2980 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2984 * If ctx1 and ctx2 have the same parent; we flatten the parent
2985 * hierarchy, see perf_event_init_context().
2987 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2988 ctx1->parent_gen == ctx2->parent_gen)
2995 static void __perf_event_sync_stat(struct perf_event *event,
2996 struct perf_event *next_event)
3000 if (!event->attr.inherit_stat)
3004 * Update the event value, we cannot use perf_event_read()
3005 * because we're in the middle of a context switch and have IRQs
3006 * disabled, which upsets smp_call_function_single(), however
3007 * we know the event must be on the current CPU, therefore we
3008 * don't need to use it.
3010 if (event->state == PERF_EVENT_STATE_ACTIVE)
3011 event->pmu->read(event);
3013 perf_event_update_time(event);
3016 * In order to keep per-task stats reliable we need to flip the event
3017 * values when we flip the contexts.
3019 value = local64_read(&next_event->count);
3020 value = local64_xchg(&event->count, value);
3021 local64_set(&next_event->count, value);
3023 swap(event->total_time_enabled, next_event->total_time_enabled);
3024 swap(event->total_time_running, next_event->total_time_running);
3027 * Since we swizzled the values, update the user visible data too.
3029 perf_event_update_userpage(event);
3030 perf_event_update_userpage(next_event);
3033 static void perf_event_sync_stat(struct perf_event_context *ctx,
3034 struct perf_event_context *next_ctx)
3036 struct perf_event *event, *next_event;
3041 update_context_time(ctx);
3043 event = list_first_entry(&ctx->event_list,
3044 struct perf_event, event_entry);
3046 next_event = list_first_entry(&next_ctx->event_list,
3047 struct perf_event, event_entry);
3049 while (&event->event_entry != &ctx->event_list &&
3050 &next_event->event_entry != &next_ctx->event_list) {
3052 __perf_event_sync_stat(event, next_event);
3054 event = list_next_entry(event, event_entry);
3055 next_event = list_next_entry(next_event, event_entry);
3059 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3060 struct task_struct *next)
3062 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3063 struct perf_event_context *next_ctx;
3064 struct perf_event_context *parent, *next_parent;
3065 struct perf_cpu_context *cpuctx;
3071 cpuctx = __get_cpu_context(ctx);
3072 if (!cpuctx->task_ctx)
3076 next_ctx = next->perf_event_ctxp[ctxn];
3080 parent = rcu_dereference(ctx->parent_ctx);
3081 next_parent = rcu_dereference(next_ctx->parent_ctx);
3083 /* If neither context have a parent context; they cannot be clones. */
3084 if (!parent && !next_parent)
3087 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3089 * Looks like the two contexts are clones, so we might be
3090 * able to optimize the context switch. We lock both
3091 * contexts and check that they are clones under the
3092 * lock (including re-checking that neither has been
3093 * uncloned in the meantime). It doesn't matter which
3094 * order we take the locks because no other cpu could
3095 * be trying to lock both of these tasks.
3097 raw_spin_lock(&ctx->lock);
3098 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3099 if (context_equiv(ctx, next_ctx)) {
3100 WRITE_ONCE(ctx->task, next);
3101 WRITE_ONCE(next_ctx->task, task);
3103 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3106 * RCU_INIT_POINTER here is safe because we've not
3107 * modified the ctx and the above modification of
3108 * ctx->task and ctx->task_ctx_data are immaterial
3109 * since those values are always verified under
3110 * ctx->lock which we're now holding.
3112 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3113 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3117 perf_event_sync_stat(ctx, next_ctx);
3119 raw_spin_unlock(&next_ctx->lock);
3120 raw_spin_unlock(&ctx->lock);
3126 raw_spin_lock(&ctx->lock);
3127 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3128 raw_spin_unlock(&ctx->lock);
3132 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3134 void perf_sched_cb_dec(struct pmu *pmu)
3136 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3138 this_cpu_dec(perf_sched_cb_usages);
3140 if (!--cpuctx->sched_cb_usage)
3141 list_del(&cpuctx->sched_cb_entry);
3145 void perf_sched_cb_inc(struct pmu *pmu)
3147 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3149 if (!cpuctx->sched_cb_usage++)
3150 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3152 this_cpu_inc(perf_sched_cb_usages);
3156 * This function provides the context switch callback to the lower code
3157 * layer. It is invoked ONLY when the context switch callback is enabled.
3159 * This callback is relevant even to per-cpu events; for example multi event
3160 * PEBS requires this to provide PID/TID information. This requires we flush
3161 * all queued PEBS records before we context switch to a new task.
3163 static void perf_pmu_sched_task(struct task_struct *prev,
3164 struct task_struct *next,
3167 struct perf_cpu_context *cpuctx;
3173 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3174 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3176 if (WARN_ON_ONCE(!pmu->sched_task))
3179 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3180 perf_pmu_disable(pmu);
3182 pmu->sched_task(cpuctx->task_ctx, sched_in);
3184 perf_pmu_enable(pmu);
3185 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3189 static void perf_event_switch(struct task_struct *task,
3190 struct task_struct *next_prev, bool sched_in);
3192 #define for_each_task_context_nr(ctxn) \
3193 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3196 * Called from scheduler to remove the events of the current task,
3197 * with interrupts disabled.
3199 * We stop each event and update the event value in event->count.
3201 * This does not protect us against NMI, but disable()
3202 * sets the disabled bit in the control field of event _before_
3203 * accessing the event control register. If a NMI hits, then it will
3204 * not restart the event.
3206 void __perf_event_task_sched_out(struct task_struct *task,
3207 struct task_struct *next)
3211 if (__this_cpu_read(perf_sched_cb_usages))
3212 perf_pmu_sched_task(task, next, false);
3214 if (atomic_read(&nr_switch_events))
3215 perf_event_switch(task, next, false);
3217 for_each_task_context_nr(ctxn)
3218 perf_event_context_sched_out(task, ctxn, next);
3221 * if cgroup events exist on this CPU, then we need
3222 * to check if we have to switch out PMU state.
3223 * cgroup event are system-wide mode only
3225 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3226 perf_cgroup_sched_out(task, next);
3230 * Called with IRQs disabled
3232 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3233 enum event_type_t event_type)
3235 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3238 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3239 int (*func)(struct perf_event *, void *), void *data)
3241 struct perf_event **evt, *evt1, *evt2;
3244 evt1 = perf_event_groups_first(groups, -1);
3245 evt2 = perf_event_groups_first(groups, cpu);
3247 while (evt1 || evt2) {
3249 if (evt1->group_index < evt2->group_index)
3259 ret = func(*evt, data);
3263 *evt = perf_event_groups_next(*evt);
3269 struct sched_in_data {
3270 struct perf_event_context *ctx;
3271 struct perf_cpu_context *cpuctx;
3275 static int pinned_sched_in(struct perf_event *event, void *data)
3277 struct sched_in_data *sid = data;
3279 if (event->state <= PERF_EVENT_STATE_OFF)
3282 if (!event_filter_match(event))
3285 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3286 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3287 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3291 * If this pinned group hasn't been scheduled,
3292 * put it in error state.
3294 if (event->state == PERF_EVENT_STATE_INACTIVE)
3295 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3300 static int flexible_sched_in(struct perf_event *event, void *data)
3302 struct sched_in_data *sid = data;
3304 if (event->state <= PERF_EVENT_STATE_OFF)
3307 if (!event_filter_match(event))
3310 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3311 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3312 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3314 sid->can_add_hw = 0;
3321 ctx_pinned_sched_in(struct perf_event_context *ctx,
3322 struct perf_cpu_context *cpuctx)
3324 struct sched_in_data sid = {
3330 visit_groups_merge(&ctx->pinned_groups,
3332 pinned_sched_in, &sid);
3336 ctx_flexible_sched_in(struct perf_event_context *ctx,
3337 struct perf_cpu_context *cpuctx)
3339 struct sched_in_data sid = {
3345 visit_groups_merge(&ctx->flexible_groups,
3347 flexible_sched_in, &sid);
3351 ctx_sched_in(struct perf_event_context *ctx,
3352 struct perf_cpu_context *cpuctx,
3353 enum event_type_t event_type,
3354 struct task_struct *task)
3356 int is_active = ctx->is_active;
3359 lockdep_assert_held(&ctx->lock);
3361 if (likely(!ctx->nr_events))
3364 ctx->is_active |= (event_type | EVENT_TIME);
3367 cpuctx->task_ctx = ctx;
3369 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3372 is_active ^= ctx->is_active; /* changed bits */
3374 if (is_active & EVENT_TIME) {
3375 /* start ctx time */
3377 ctx->timestamp = now;
3378 perf_cgroup_set_timestamp(task, ctx);
3382 * First go through the list and put on any pinned groups
3383 * in order to give them the best chance of going on.
3385 if (is_active & EVENT_PINNED)
3386 ctx_pinned_sched_in(ctx, cpuctx);
3388 /* Then walk through the lower prio flexible groups */
3389 if (is_active & EVENT_FLEXIBLE)
3390 ctx_flexible_sched_in(ctx, cpuctx);
3393 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3394 enum event_type_t event_type,
3395 struct task_struct *task)
3397 struct perf_event_context *ctx = &cpuctx->ctx;
3399 ctx_sched_in(ctx, cpuctx, event_type, task);
3402 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3403 struct task_struct *task)
3405 struct perf_cpu_context *cpuctx;
3407 cpuctx = __get_cpu_context(ctx);
3408 if (cpuctx->task_ctx == ctx)
3411 perf_ctx_lock(cpuctx, ctx);
3413 * We must check ctx->nr_events while holding ctx->lock, such
3414 * that we serialize against perf_install_in_context().
3416 if (!ctx->nr_events)
3419 perf_pmu_disable(ctx->pmu);
3421 * We want to keep the following priority order:
3422 * cpu pinned (that don't need to move), task pinned,
3423 * cpu flexible, task flexible.
3425 * However, if task's ctx is not carrying any pinned
3426 * events, no need to flip the cpuctx's events around.
3428 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3429 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3430 perf_event_sched_in(cpuctx, ctx, task);
3431 perf_pmu_enable(ctx->pmu);
3434 perf_ctx_unlock(cpuctx, ctx);
3438 * Called from scheduler to add the events of the current task
3439 * with interrupts disabled.
3441 * We restore the event value and then enable it.
3443 * This does not protect us against NMI, but enable()
3444 * sets the enabled bit in the control field of event _before_
3445 * accessing the event control register. If a NMI hits, then it will
3446 * keep the event running.
3448 void __perf_event_task_sched_in(struct task_struct *prev,
3449 struct task_struct *task)
3451 struct perf_event_context *ctx;
3455 * If cgroup events exist on this CPU, then we need to check if we have
3456 * to switch in PMU state; cgroup event are system-wide mode only.
3458 * Since cgroup events are CPU events, we must schedule these in before
3459 * we schedule in the task events.
3461 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3462 perf_cgroup_sched_in(prev, task);
3464 for_each_task_context_nr(ctxn) {
3465 ctx = task->perf_event_ctxp[ctxn];
3469 perf_event_context_sched_in(ctx, task);
3472 if (atomic_read(&nr_switch_events))
3473 perf_event_switch(task, prev, true);
3475 if (__this_cpu_read(perf_sched_cb_usages))
3476 perf_pmu_sched_task(prev, task, true);
3479 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3481 u64 frequency = event->attr.sample_freq;
3482 u64 sec = NSEC_PER_SEC;
3483 u64 divisor, dividend;
3485 int count_fls, nsec_fls, frequency_fls, sec_fls;
3487 count_fls = fls64(count);
3488 nsec_fls = fls64(nsec);
3489 frequency_fls = fls64(frequency);
3493 * We got @count in @nsec, with a target of sample_freq HZ
3494 * the target period becomes:
3497 * period = -------------------
3498 * @nsec * sample_freq
3503 * Reduce accuracy by one bit such that @a and @b converge
3504 * to a similar magnitude.
3506 #define REDUCE_FLS(a, b) \
3508 if (a##_fls > b##_fls) { \
3518 * Reduce accuracy until either term fits in a u64, then proceed with
3519 * the other, so that finally we can do a u64/u64 division.
3521 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3522 REDUCE_FLS(nsec, frequency);
3523 REDUCE_FLS(sec, count);
3526 if (count_fls + sec_fls > 64) {
3527 divisor = nsec * frequency;
3529 while (count_fls + sec_fls > 64) {
3530 REDUCE_FLS(count, sec);
3534 dividend = count * sec;
3536 dividend = count * sec;
3538 while (nsec_fls + frequency_fls > 64) {
3539 REDUCE_FLS(nsec, frequency);
3543 divisor = nsec * frequency;
3549 return div64_u64(dividend, divisor);
3552 static DEFINE_PER_CPU(int, perf_throttled_count);
3553 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3555 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3557 struct hw_perf_event *hwc = &event->hw;
3558 s64 period, sample_period;
3561 period = perf_calculate_period(event, nsec, count);
3563 delta = (s64)(period - hwc->sample_period);
3564 delta = (delta + 7) / 8; /* low pass filter */
3566 sample_period = hwc->sample_period + delta;
3571 hwc->sample_period = sample_period;
3573 if (local64_read(&hwc->period_left) > 8*sample_period) {
3575 event->pmu->stop(event, PERF_EF_UPDATE);
3577 local64_set(&hwc->period_left, 0);
3580 event->pmu->start(event, PERF_EF_RELOAD);
3585 * combine freq adjustment with unthrottling to avoid two passes over the
3586 * events. At the same time, make sure, having freq events does not change
3587 * the rate of unthrottling as that would introduce bias.
3589 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3592 struct perf_event *event;
3593 struct hw_perf_event *hwc;
3594 u64 now, period = TICK_NSEC;
3598 * only need to iterate over all events iff:
3599 * - context have events in frequency mode (needs freq adjust)
3600 * - there are events to unthrottle on this cpu
3602 if (!(ctx->nr_freq || needs_unthr))
3605 raw_spin_lock(&ctx->lock);
3606 perf_pmu_disable(ctx->pmu);
3608 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3609 if (event->state != PERF_EVENT_STATE_ACTIVE)
3612 if (!event_filter_match(event))
3615 perf_pmu_disable(event->pmu);
3619 if (hwc->interrupts == MAX_INTERRUPTS) {
3620 hwc->interrupts = 0;
3621 perf_log_throttle(event, 1);
3622 event->pmu->start(event, 0);
3625 if (!event->attr.freq || !event->attr.sample_freq)
3629 * stop the event and update event->count
3631 event->pmu->stop(event, PERF_EF_UPDATE);
3633 now = local64_read(&event->count);
3634 delta = now - hwc->freq_count_stamp;
3635 hwc->freq_count_stamp = now;
3639 * reload only if value has changed
3640 * we have stopped the event so tell that
3641 * to perf_adjust_period() to avoid stopping it
3645 perf_adjust_period(event, period, delta, false);
3647 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3649 perf_pmu_enable(event->pmu);
3652 perf_pmu_enable(ctx->pmu);
3653 raw_spin_unlock(&ctx->lock);
3657 * Move @event to the tail of the @ctx's elegible events.
3659 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3662 * Rotate the first entry last of non-pinned groups. Rotation might be
3663 * disabled by the inheritance code.
3665 if (ctx->rotate_disable)
3668 perf_event_groups_delete(&ctx->flexible_groups, event);
3669 perf_event_groups_insert(&ctx->flexible_groups, event);
3672 static inline struct perf_event *
3673 ctx_first_active(struct perf_event_context *ctx)
3675 return list_first_entry_or_null(&ctx->flexible_active,
3676 struct perf_event, active_list);
3679 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3681 struct perf_event *cpu_event = NULL, *task_event = NULL;
3682 bool cpu_rotate = false, task_rotate = false;
3683 struct perf_event_context *ctx = NULL;
3686 * Since we run this from IRQ context, nobody can install new
3687 * events, thus the event count values are stable.
3690 if (cpuctx->ctx.nr_events) {
3691 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3695 ctx = cpuctx->task_ctx;
3696 if (ctx && ctx->nr_events) {
3697 if (ctx->nr_events != ctx->nr_active)
3701 if (!(cpu_rotate || task_rotate))
3704 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3705 perf_pmu_disable(cpuctx->ctx.pmu);
3708 task_event = ctx_first_active(ctx);
3710 cpu_event = ctx_first_active(&cpuctx->ctx);
3713 * As per the order given at ctx_resched() first 'pop' task flexible
3714 * and then, if needed CPU flexible.
3716 if (task_event || (ctx && cpu_event))
3717 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3719 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3722 rotate_ctx(ctx, task_event);
3724 rotate_ctx(&cpuctx->ctx, cpu_event);
3726 perf_event_sched_in(cpuctx, ctx, current);
3728 perf_pmu_enable(cpuctx->ctx.pmu);
3729 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3734 void perf_event_task_tick(void)
3736 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3737 struct perf_event_context *ctx, *tmp;
3740 lockdep_assert_irqs_disabled();
3742 __this_cpu_inc(perf_throttled_seq);
3743 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3744 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3746 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3747 perf_adjust_freq_unthr_context(ctx, throttled);
3750 static int event_enable_on_exec(struct perf_event *event,
3751 struct perf_event_context *ctx)
3753 if (!event->attr.enable_on_exec)
3756 event->attr.enable_on_exec = 0;
3757 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3760 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3766 * Enable all of a task's events that have been marked enable-on-exec.
3767 * This expects task == current.
3769 static void perf_event_enable_on_exec(int ctxn)
3771 struct perf_event_context *ctx, *clone_ctx = NULL;
3772 enum event_type_t event_type = 0;
3773 struct perf_cpu_context *cpuctx;
3774 struct perf_event *event;
3775 unsigned long flags;
3778 local_irq_save(flags);
3779 ctx = current->perf_event_ctxp[ctxn];
3780 if (!ctx || !ctx->nr_events)
3783 cpuctx = __get_cpu_context(ctx);
3784 perf_ctx_lock(cpuctx, ctx);
3785 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3786 list_for_each_entry(event, &ctx->event_list, event_entry) {
3787 enabled |= event_enable_on_exec(event, ctx);
3788 event_type |= get_event_type(event);
3792 * Unclone and reschedule this context if we enabled any event.
3795 clone_ctx = unclone_ctx(ctx);
3796 ctx_resched(cpuctx, ctx, event_type);
3798 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3800 perf_ctx_unlock(cpuctx, ctx);
3803 local_irq_restore(flags);
3809 struct perf_read_data {
3810 struct perf_event *event;
3815 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3817 u16 local_pkg, event_pkg;
3819 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3820 int local_cpu = smp_processor_id();
3822 event_pkg = topology_physical_package_id(event_cpu);
3823 local_pkg = topology_physical_package_id(local_cpu);
3825 if (event_pkg == local_pkg)
3833 * Cross CPU call to read the hardware event
3835 static void __perf_event_read(void *info)
3837 struct perf_read_data *data = info;
3838 struct perf_event *sub, *event = data->event;
3839 struct perf_event_context *ctx = event->ctx;
3840 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3841 struct pmu *pmu = event->pmu;
3844 * If this is a task context, we need to check whether it is
3845 * the current task context of this cpu. If not it has been
3846 * scheduled out before the smp call arrived. In that case
3847 * event->count would have been updated to a recent sample
3848 * when the event was scheduled out.
3850 if (ctx->task && cpuctx->task_ctx != ctx)
3853 raw_spin_lock(&ctx->lock);
3854 if (ctx->is_active & EVENT_TIME) {
3855 update_context_time(ctx);
3856 update_cgrp_time_from_event(event);
3859 perf_event_update_time(event);
3861 perf_event_update_sibling_time(event);
3863 if (event->state != PERF_EVENT_STATE_ACTIVE)
3872 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3876 for_each_sibling_event(sub, event) {
3877 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3879 * Use sibling's PMU rather than @event's since
3880 * sibling could be on different (eg: software) PMU.
3882 sub->pmu->read(sub);
3886 data->ret = pmu->commit_txn(pmu);
3889 raw_spin_unlock(&ctx->lock);
3892 static inline u64 perf_event_count(struct perf_event *event)
3894 return local64_read(&event->count) + atomic64_read(&event->child_count);
3898 * NMI-safe method to read a local event, that is an event that
3900 * - either for the current task, or for this CPU
3901 * - does not have inherit set, for inherited task events
3902 * will not be local and we cannot read them atomically
3903 * - must not have a pmu::count method
3905 int perf_event_read_local(struct perf_event *event, u64 *value,
3906 u64 *enabled, u64 *running)
3908 unsigned long flags;
3912 * Disabling interrupts avoids all counter scheduling (context
3913 * switches, timer based rotation and IPIs).
3915 local_irq_save(flags);
3918 * It must not be an event with inherit set, we cannot read
3919 * all child counters from atomic context.
3921 if (event->attr.inherit) {
3926 /* If this is a per-task event, it must be for current */
3927 if ((event->attach_state & PERF_ATTACH_TASK) &&
3928 event->hw.target != current) {
3933 /* If this is a per-CPU event, it must be for this CPU */
3934 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3935 event->cpu != smp_processor_id()) {
3940 /* If this is a pinned event it must be running on this CPU */
3941 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3947 * If the event is currently on this CPU, its either a per-task event,
3948 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3951 if (event->oncpu == smp_processor_id())
3952 event->pmu->read(event);
3954 *value = local64_read(&event->count);
3955 if (enabled || running) {
3956 u64 now = event->shadow_ctx_time + perf_clock();
3957 u64 __enabled, __running;
3959 __perf_update_times(event, now, &__enabled, &__running);
3961 *enabled = __enabled;
3963 *running = __running;
3966 local_irq_restore(flags);
3971 static int perf_event_read(struct perf_event *event, bool group)
3973 enum perf_event_state state = READ_ONCE(event->state);
3974 int event_cpu, ret = 0;
3977 * If event is enabled and currently active on a CPU, update the
3978 * value in the event structure:
3981 if (state == PERF_EVENT_STATE_ACTIVE) {
3982 struct perf_read_data data;
3985 * Orders the ->state and ->oncpu loads such that if we see
3986 * ACTIVE we must also see the right ->oncpu.
3988 * Matches the smp_wmb() from event_sched_in().
3992 event_cpu = READ_ONCE(event->oncpu);
3993 if ((unsigned)event_cpu >= nr_cpu_ids)
3996 data = (struct perf_read_data){
4003 event_cpu = __perf_event_read_cpu(event, event_cpu);
4006 * Purposely ignore the smp_call_function_single() return
4009 * If event_cpu isn't a valid CPU it means the event got
4010 * scheduled out and that will have updated the event count.
4012 * Therefore, either way, we'll have an up-to-date event count
4015 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4019 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4020 struct perf_event_context *ctx = event->ctx;
4021 unsigned long flags;
4023 raw_spin_lock_irqsave(&ctx->lock, flags);
4024 state = event->state;
4025 if (state != PERF_EVENT_STATE_INACTIVE) {
4026 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4031 * May read while context is not active (e.g., thread is
4032 * blocked), in that case we cannot update context time
4034 if (ctx->is_active & EVENT_TIME) {
4035 update_context_time(ctx);
4036 update_cgrp_time_from_event(event);
4039 perf_event_update_time(event);
4041 perf_event_update_sibling_time(event);
4042 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4049 * Initialize the perf_event context in a task_struct:
4051 static void __perf_event_init_context(struct perf_event_context *ctx)
4053 raw_spin_lock_init(&ctx->lock);
4054 mutex_init(&ctx->mutex);
4055 INIT_LIST_HEAD(&ctx->active_ctx_list);
4056 perf_event_groups_init(&ctx->pinned_groups);
4057 perf_event_groups_init(&ctx->flexible_groups);
4058 INIT_LIST_HEAD(&ctx->event_list);
4059 INIT_LIST_HEAD(&ctx->pinned_active);
4060 INIT_LIST_HEAD(&ctx->flexible_active);
4061 refcount_set(&ctx->refcount, 1);
4064 static struct perf_event_context *
4065 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4067 struct perf_event_context *ctx;
4069 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4073 __perf_event_init_context(ctx);
4076 get_task_struct(task);
4083 static struct task_struct *
4084 find_lively_task_by_vpid(pid_t vpid)
4086 struct task_struct *task;
4092 task = find_task_by_vpid(vpid);
4094 get_task_struct(task);
4098 return ERR_PTR(-ESRCH);
4104 * Returns a matching context with refcount and pincount.
4106 static struct perf_event_context *
4107 find_get_context(struct pmu *pmu, struct task_struct *task,
4108 struct perf_event *event)
4110 struct perf_event_context *ctx, *clone_ctx = NULL;
4111 struct perf_cpu_context *cpuctx;
4112 void *task_ctx_data = NULL;
4113 unsigned long flags;
4115 int cpu = event->cpu;
4118 /* Must be root to operate on a CPU event: */
4119 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4120 return ERR_PTR(-EACCES);
4122 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4131 ctxn = pmu->task_ctx_nr;
4135 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4136 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4137 if (!task_ctx_data) {
4144 ctx = perf_lock_task_context(task, ctxn, &flags);
4146 clone_ctx = unclone_ctx(ctx);
4149 if (task_ctx_data && !ctx->task_ctx_data) {
4150 ctx->task_ctx_data = task_ctx_data;
4151 task_ctx_data = NULL;
4153 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4158 ctx = alloc_perf_context(pmu, task);
4163 if (task_ctx_data) {
4164 ctx->task_ctx_data = task_ctx_data;
4165 task_ctx_data = NULL;
4169 mutex_lock(&task->perf_event_mutex);
4171 * If it has already passed perf_event_exit_task().
4172 * we must see PF_EXITING, it takes this mutex too.
4174 if (task->flags & PF_EXITING)
4176 else if (task->perf_event_ctxp[ctxn])
4181 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4183 mutex_unlock(&task->perf_event_mutex);
4185 if (unlikely(err)) {
4194 kfree(task_ctx_data);
4198 kfree(task_ctx_data);
4199 return ERR_PTR(err);
4202 static void perf_event_free_filter(struct perf_event *event);
4203 static void perf_event_free_bpf_prog(struct perf_event *event);
4205 static void free_event_rcu(struct rcu_head *head)
4207 struct perf_event *event;
4209 event = container_of(head, struct perf_event, rcu_head);
4211 put_pid_ns(event->ns);
4212 perf_event_free_filter(event);
4216 static void ring_buffer_attach(struct perf_event *event,
4217 struct ring_buffer *rb);
4219 static void detach_sb_event(struct perf_event *event)
4221 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4223 raw_spin_lock(&pel->lock);
4224 list_del_rcu(&event->sb_list);
4225 raw_spin_unlock(&pel->lock);
4228 static bool is_sb_event(struct perf_event *event)
4230 struct perf_event_attr *attr = &event->attr;
4235 if (event->attach_state & PERF_ATTACH_TASK)
4238 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4239 attr->comm || attr->comm_exec ||
4240 attr->task || attr->ksymbol ||
4241 attr->context_switch ||
4247 static void unaccount_pmu_sb_event(struct perf_event *event)
4249 if (is_sb_event(event))
4250 detach_sb_event(event);
4253 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4258 if (is_cgroup_event(event))
4259 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4262 #ifdef CONFIG_NO_HZ_FULL
4263 static DEFINE_SPINLOCK(nr_freq_lock);
4266 static void unaccount_freq_event_nohz(void)
4268 #ifdef CONFIG_NO_HZ_FULL
4269 spin_lock(&nr_freq_lock);
4270 if (atomic_dec_and_test(&nr_freq_events))
4271 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4272 spin_unlock(&nr_freq_lock);
4276 static void unaccount_freq_event(void)
4278 if (tick_nohz_full_enabled())
4279 unaccount_freq_event_nohz();
4281 atomic_dec(&nr_freq_events);
4284 static void unaccount_event(struct perf_event *event)
4291 if (event->attach_state & PERF_ATTACH_TASK)
4293 if (event->attr.mmap || event->attr.mmap_data)
4294 atomic_dec(&nr_mmap_events);
4295 if (event->attr.comm)
4296 atomic_dec(&nr_comm_events);
4297 if (event->attr.namespaces)
4298 atomic_dec(&nr_namespaces_events);
4299 if (event->attr.task)
4300 atomic_dec(&nr_task_events);
4301 if (event->attr.freq)
4302 unaccount_freq_event();
4303 if (event->attr.context_switch) {
4305 atomic_dec(&nr_switch_events);
4307 if (is_cgroup_event(event))
4309 if (has_branch_stack(event))
4311 if (event->attr.ksymbol)
4312 atomic_dec(&nr_ksymbol_events);
4313 if (event->attr.bpf_event)
4314 atomic_dec(&nr_bpf_events);
4317 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4318 schedule_delayed_work(&perf_sched_work, HZ);
4321 unaccount_event_cpu(event, event->cpu);
4323 unaccount_pmu_sb_event(event);
4326 static void perf_sched_delayed(struct work_struct *work)
4328 mutex_lock(&perf_sched_mutex);
4329 if (atomic_dec_and_test(&perf_sched_count))
4330 static_branch_disable(&perf_sched_events);
4331 mutex_unlock(&perf_sched_mutex);
4335 * The following implement mutual exclusion of events on "exclusive" pmus
4336 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4337 * at a time, so we disallow creating events that might conflict, namely:
4339 * 1) cpu-wide events in the presence of per-task events,
4340 * 2) per-task events in the presence of cpu-wide events,
4341 * 3) two matching events on the same context.
4343 * The former two cases are handled in the allocation path (perf_event_alloc(),
4344 * _free_event()), the latter -- before the first perf_install_in_context().
4346 static int exclusive_event_init(struct perf_event *event)
4348 struct pmu *pmu = event->pmu;
4350 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4354 * Prevent co-existence of per-task and cpu-wide events on the
4355 * same exclusive pmu.
4357 * Negative pmu::exclusive_cnt means there are cpu-wide
4358 * events on this "exclusive" pmu, positive means there are
4361 * Since this is called in perf_event_alloc() path, event::ctx
4362 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4363 * to mean "per-task event", because unlike other attach states it
4364 * never gets cleared.
4366 if (event->attach_state & PERF_ATTACH_TASK) {
4367 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4370 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4377 static void exclusive_event_destroy(struct perf_event *event)
4379 struct pmu *pmu = event->pmu;
4381 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4384 /* see comment in exclusive_event_init() */
4385 if (event->attach_state & PERF_ATTACH_TASK)
4386 atomic_dec(&pmu->exclusive_cnt);
4388 atomic_inc(&pmu->exclusive_cnt);
4391 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4393 if ((e1->pmu == e2->pmu) &&
4394 (e1->cpu == e2->cpu ||
4401 /* Called under the same ctx::mutex as perf_install_in_context() */
4402 static bool exclusive_event_installable(struct perf_event *event,
4403 struct perf_event_context *ctx)
4405 struct perf_event *iter_event;
4406 struct pmu *pmu = event->pmu;
4408 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4411 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4412 if (exclusive_event_match(iter_event, event))
4419 static void perf_addr_filters_splice(struct perf_event *event,
4420 struct list_head *head);
4422 static void _free_event(struct perf_event *event)
4424 irq_work_sync(&event->pending);
4426 unaccount_event(event);
4430 * Can happen when we close an event with re-directed output.
4432 * Since we have a 0 refcount, perf_mmap_close() will skip
4433 * over us; possibly making our ring_buffer_put() the last.
4435 mutex_lock(&event->mmap_mutex);
4436 ring_buffer_attach(event, NULL);
4437 mutex_unlock(&event->mmap_mutex);
4440 if (is_cgroup_event(event))
4441 perf_detach_cgroup(event);
4443 if (!event->parent) {
4444 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4445 put_callchain_buffers();
4448 perf_event_free_bpf_prog(event);
4449 perf_addr_filters_splice(event, NULL);
4450 kfree(event->addr_filter_ranges);
4453 event->destroy(event);
4456 put_ctx(event->ctx);
4458 if (event->hw.target)
4459 put_task_struct(event->hw.target);
4461 exclusive_event_destroy(event);
4462 module_put(event->pmu->module);
4464 call_rcu(&event->rcu_head, free_event_rcu);
4468 * Used to free events which have a known refcount of 1, such as in error paths
4469 * where the event isn't exposed yet and inherited events.
4471 static void free_event(struct perf_event *event)
4473 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4474 "unexpected event refcount: %ld; ptr=%p\n",
4475 atomic_long_read(&event->refcount), event)) {
4476 /* leak to avoid use-after-free */
4484 * Remove user event from the owner task.
4486 static void perf_remove_from_owner(struct perf_event *event)
4488 struct task_struct *owner;
4492 * Matches the smp_store_release() in perf_event_exit_task(). If we
4493 * observe !owner it means the list deletion is complete and we can
4494 * indeed free this event, otherwise we need to serialize on
4495 * owner->perf_event_mutex.
4497 owner = READ_ONCE(event->owner);
4500 * Since delayed_put_task_struct() also drops the last
4501 * task reference we can safely take a new reference
4502 * while holding the rcu_read_lock().
4504 get_task_struct(owner);
4510 * If we're here through perf_event_exit_task() we're already
4511 * holding ctx->mutex which would be an inversion wrt. the
4512 * normal lock order.
4514 * However we can safely take this lock because its the child
4517 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4520 * We have to re-check the event->owner field, if it is cleared
4521 * we raced with perf_event_exit_task(), acquiring the mutex
4522 * ensured they're done, and we can proceed with freeing the
4526 list_del_init(&event->owner_entry);
4527 smp_store_release(&event->owner, NULL);
4529 mutex_unlock(&owner->perf_event_mutex);
4530 put_task_struct(owner);
4534 static void put_event(struct perf_event *event)
4536 if (!atomic_long_dec_and_test(&event->refcount))
4543 * Kill an event dead; while event:refcount will preserve the event
4544 * object, it will not preserve its functionality. Once the last 'user'
4545 * gives up the object, we'll destroy the thing.
4547 int perf_event_release_kernel(struct perf_event *event)
4549 struct perf_event_context *ctx = event->ctx;
4550 struct perf_event *child, *tmp;
4551 LIST_HEAD(free_list);
4554 * If we got here through err_file: fput(event_file); we will not have
4555 * attached to a context yet.
4558 WARN_ON_ONCE(event->attach_state &
4559 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4563 if (!is_kernel_event(event))
4564 perf_remove_from_owner(event);
4566 ctx = perf_event_ctx_lock(event);
4567 WARN_ON_ONCE(ctx->parent_ctx);
4568 perf_remove_from_context(event, DETACH_GROUP);
4570 raw_spin_lock_irq(&ctx->lock);
4572 * Mark this event as STATE_DEAD, there is no external reference to it
4575 * Anybody acquiring event->child_mutex after the below loop _must_
4576 * also see this, most importantly inherit_event() which will avoid
4577 * placing more children on the list.
4579 * Thus this guarantees that we will in fact observe and kill _ALL_
4582 event->state = PERF_EVENT_STATE_DEAD;
4583 raw_spin_unlock_irq(&ctx->lock);
4585 perf_event_ctx_unlock(event, ctx);
4588 mutex_lock(&event->child_mutex);
4589 list_for_each_entry(child, &event->child_list, child_list) {
4592 * Cannot change, child events are not migrated, see the
4593 * comment with perf_event_ctx_lock_nested().
4595 ctx = READ_ONCE(child->ctx);
4597 * Since child_mutex nests inside ctx::mutex, we must jump
4598 * through hoops. We start by grabbing a reference on the ctx.
4600 * Since the event cannot get freed while we hold the
4601 * child_mutex, the context must also exist and have a !0
4607 * Now that we have a ctx ref, we can drop child_mutex, and
4608 * acquire ctx::mutex without fear of it going away. Then we
4609 * can re-acquire child_mutex.
4611 mutex_unlock(&event->child_mutex);
4612 mutex_lock(&ctx->mutex);
4613 mutex_lock(&event->child_mutex);
4616 * Now that we hold ctx::mutex and child_mutex, revalidate our
4617 * state, if child is still the first entry, it didn't get freed
4618 * and we can continue doing so.
4620 tmp = list_first_entry_or_null(&event->child_list,
4621 struct perf_event, child_list);
4623 perf_remove_from_context(child, DETACH_GROUP);
4624 list_move(&child->child_list, &free_list);
4626 * This matches the refcount bump in inherit_event();
4627 * this can't be the last reference.
4632 mutex_unlock(&event->child_mutex);
4633 mutex_unlock(&ctx->mutex);
4637 mutex_unlock(&event->child_mutex);
4639 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4640 list_del(&child->child_list);
4645 put_event(event); /* Must be the 'last' reference */
4648 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4651 * Called when the last reference to the file is gone.
4653 static int perf_release(struct inode *inode, struct file *file)
4655 perf_event_release_kernel(file->private_data);
4659 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4661 struct perf_event *child;
4667 mutex_lock(&event->child_mutex);
4669 (void)perf_event_read(event, false);
4670 total += perf_event_count(event);
4672 *enabled += event->total_time_enabled +
4673 atomic64_read(&event->child_total_time_enabled);
4674 *running += event->total_time_running +
4675 atomic64_read(&event->child_total_time_running);
4677 list_for_each_entry(child, &event->child_list, child_list) {
4678 (void)perf_event_read(child, false);
4679 total += perf_event_count(child);
4680 *enabled += child->total_time_enabled;
4681 *running += child->total_time_running;
4683 mutex_unlock(&event->child_mutex);
4688 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4690 struct perf_event_context *ctx;
4693 ctx = perf_event_ctx_lock(event);
4694 count = __perf_event_read_value(event, enabled, running);
4695 perf_event_ctx_unlock(event, ctx);
4699 EXPORT_SYMBOL_GPL(perf_event_read_value);
4701 static int __perf_read_group_add(struct perf_event *leader,
4702 u64 read_format, u64 *values)
4704 struct perf_event_context *ctx = leader->ctx;
4705 struct perf_event *sub;
4706 unsigned long flags;
4707 int n = 1; /* skip @nr */
4710 ret = perf_event_read(leader, true);
4714 raw_spin_lock_irqsave(&ctx->lock, flags);
4717 * Since we co-schedule groups, {enabled,running} times of siblings
4718 * will be identical to those of the leader, so we only publish one
4721 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4722 values[n++] += leader->total_time_enabled +
4723 atomic64_read(&leader->child_total_time_enabled);
4726 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4727 values[n++] += leader->total_time_running +
4728 atomic64_read(&leader->child_total_time_running);
4732 * Write {count,id} tuples for every sibling.
4734 values[n++] += perf_event_count(leader);
4735 if (read_format & PERF_FORMAT_ID)
4736 values[n++] = primary_event_id(leader);
4738 for_each_sibling_event(sub, leader) {
4739 values[n++] += perf_event_count(sub);
4740 if (read_format & PERF_FORMAT_ID)
4741 values[n++] = primary_event_id(sub);
4744 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4748 static int perf_read_group(struct perf_event *event,
4749 u64 read_format, char __user *buf)
4751 struct perf_event *leader = event->group_leader, *child;
4752 struct perf_event_context *ctx = leader->ctx;
4756 lockdep_assert_held(&ctx->mutex);
4758 values = kzalloc(event->read_size, GFP_KERNEL);
4762 values[0] = 1 + leader->nr_siblings;
4765 * By locking the child_mutex of the leader we effectively
4766 * lock the child list of all siblings.. XXX explain how.
4768 mutex_lock(&leader->child_mutex);
4770 ret = __perf_read_group_add(leader, read_format, values);
4774 list_for_each_entry(child, &leader->child_list, child_list) {
4775 ret = __perf_read_group_add(child, read_format, values);
4780 mutex_unlock(&leader->child_mutex);
4782 ret = event->read_size;
4783 if (copy_to_user(buf, values, event->read_size))
4788 mutex_unlock(&leader->child_mutex);
4794 static int perf_read_one(struct perf_event *event,
4795 u64 read_format, char __user *buf)
4797 u64 enabled, running;
4801 values[n++] = __perf_event_read_value(event, &enabled, &running);
4802 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4803 values[n++] = enabled;
4804 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4805 values[n++] = running;
4806 if (read_format & PERF_FORMAT_ID)
4807 values[n++] = primary_event_id(event);
4809 if (copy_to_user(buf, values, n * sizeof(u64)))
4812 return n * sizeof(u64);
4815 static bool is_event_hup(struct perf_event *event)
4819 if (event->state > PERF_EVENT_STATE_EXIT)
4822 mutex_lock(&event->child_mutex);
4823 no_children = list_empty(&event->child_list);
4824 mutex_unlock(&event->child_mutex);
4829 * Read the performance event - simple non blocking version for now
4832 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4834 u64 read_format = event->attr.read_format;
4838 * Return end-of-file for a read on an event that is in
4839 * error state (i.e. because it was pinned but it couldn't be
4840 * scheduled on to the CPU at some point).
4842 if (event->state == PERF_EVENT_STATE_ERROR)
4845 if (count < event->read_size)
4848 WARN_ON_ONCE(event->ctx->parent_ctx);
4849 if (read_format & PERF_FORMAT_GROUP)
4850 ret = perf_read_group(event, read_format, buf);
4852 ret = perf_read_one(event, read_format, buf);
4858 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4860 struct perf_event *event = file->private_data;
4861 struct perf_event_context *ctx;
4864 ctx = perf_event_ctx_lock(event);
4865 ret = __perf_read(event, buf, count);
4866 perf_event_ctx_unlock(event, ctx);
4871 static __poll_t perf_poll(struct file *file, poll_table *wait)
4873 struct perf_event *event = file->private_data;
4874 struct ring_buffer *rb;
4875 __poll_t events = EPOLLHUP;
4877 poll_wait(file, &event->waitq, wait);
4879 if (is_event_hup(event))
4883 * Pin the event->rb by taking event->mmap_mutex; otherwise
4884 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4886 mutex_lock(&event->mmap_mutex);
4889 events = atomic_xchg(&rb->poll, 0);
4890 mutex_unlock(&event->mmap_mutex);
4894 static void _perf_event_reset(struct perf_event *event)
4896 (void)perf_event_read(event, false);
4897 local64_set(&event->count, 0);
4898 perf_event_update_userpage(event);
4902 * Holding the top-level event's child_mutex means that any
4903 * descendant process that has inherited this event will block
4904 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4905 * task existence requirements of perf_event_enable/disable.
4907 static void perf_event_for_each_child(struct perf_event *event,
4908 void (*func)(struct perf_event *))
4910 struct perf_event *child;
4912 WARN_ON_ONCE(event->ctx->parent_ctx);
4914 mutex_lock(&event->child_mutex);
4916 list_for_each_entry(child, &event->child_list, child_list)
4918 mutex_unlock(&event->child_mutex);
4921 static void perf_event_for_each(struct perf_event *event,
4922 void (*func)(struct perf_event *))
4924 struct perf_event_context *ctx = event->ctx;
4925 struct perf_event *sibling;
4927 lockdep_assert_held(&ctx->mutex);
4929 event = event->group_leader;
4931 perf_event_for_each_child(event, func);
4932 for_each_sibling_event(sibling, event)
4933 perf_event_for_each_child(sibling, func);
4936 static void __perf_event_period(struct perf_event *event,
4937 struct perf_cpu_context *cpuctx,
4938 struct perf_event_context *ctx,
4941 u64 value = *((u64 *)info);
4944 if (event->attr.freq) {
4945 event->attr.sample_freq = value;
4947 event->attr.sample_period = value;
4948 event->hw.sample_period = value;
4951 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4953 perf_pmu_disable(ctx->pmu);
4955 * We could be throttled; unthrottle now to avoid the tick
4956 * trying to unthrottle while we already re-started the event.
4958 if (event->hw.interrupts == MAX_INTERRUPTS) {
4959 event->hw.interrupts = 0;
4960 perf_log_throttle(event, 1);
4962 event->pmu->stop(event, PERF_EF_UPDATE);
4965 local64_set(&event->hw.period_left, 0);
4968 event->pmu->start(event, PERF_EF_RELOAD);
4969 perf_pmu_enable(ctx->pmu);
4973 static int perf_event_check_period(struct perf_event *event, u64 value)
4975 return event->pmu->check_period(event, value);
4978 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4982 if (!is_sampling_event(event))
4985 if (copy_from_user(&value, arg, sizeof(value)))
4991 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4994 if (perf_event_check_period(event, value))
4997 event_function_call(event, __perf_event_period, &value);
5002 static const struct file_operations perf_fops;
5004 static inline int perf_fget_light(int fd, struct fd *p)
5006 struct fd f = fdget(fd);
5010 if (f.file->f_op != &perf_fops) {
5018 static int perf_event_set_output(struct perf_event *event,
5019 struct perf_event *output_event);
5020 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5021 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5022 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5023 struct perf_event_attr *attr);
5025 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5027 void (*func)(struct perf_event *);
5031 case PERF_EVENT_IOC_ENABLE:
5032 func = _perf_event_enable;
5034 case PERF_EVENT_IOC_DISABLE:
5035 func = _perf_event_disable;
5037 case PERF_EVENT_IOC_RESET:
5038 func = _perf_event_reset;
5041 case PERF_EVENT_IOC_REFRESH:
5042 return _perf_event_refresh(event, arg);
5044 case PERF_EVENT_IOC_PERIOD:
5045 return perf_event_period(event, (u64 __user *)arg);
5047 case PERF_EVENT_IOC_ID:
5049 u64 id = primary_event_id(event);
5051 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5056 case PERF_EVENT_IOC_SET_OUTPUT:
5060 struct perf_event *output_event;
5062 ret = perf_fget_light(arg, &output);
5065 output_event = output.file->private_data;
5066 ret = perf_event_set_output(event, output_event);
5069 ret = perf_event_set_output(event, NULL);
5074 case PERF_EVENT_IOC_SET_FILTER:
5075 return perf_event_set_filter(event, (void __user *)arg);
5077 case PERF_EVENT_IOC_SET_BPF:
5078 return perf_event_set_bpf_prog(event, arg);
5080 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5081 struct ring_buffer *rb;
5084 rb = rcu_dereference(event->rb);
5085 if (!rb || !rb->nr_pages) {
5089 rb_toggle_paused(rb, !!arg);
5094 case PERF_EVENT_IOC_QUERY_BPF:
5095 return perf_event_query_prog_array(event, (void __user *)arg);
5097 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5098 struct perf_event_attr new_attr;
5099 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5105 return perf_event_modify_attr(event, &new_attr);
5111 if (flags & PERF_IOC_FLAG_GROUP)
5112 perf_event_for_each(event, func);
5114 perf_event_for_each_child(event, func);
5119 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5121 struct perf_event *event = file->private_data;
5122 struct perf_event_context *ctx;
5125 ctx = perf_event_ctx_lock(event);
5126 ret = _perf_ioctl(event, cmd, arg);
5127 perf_event_ctx_unlock(event, ctx);
5132 #ifdef CONFIG_COMPAT
5133 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5136 switch (_IOC_NR(cmd)) {
5137 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5138 case _IOC_NR(PERF_EVENT_IOC_ID):
5139 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5140 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5141 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5142 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5143 cmd &= ~IOCSIZE_MASK;
5144 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5148 return perf_ioctl(file, cmd, arg);
5151 # define perf_compat_ioctl NULL
5154 int perf_event_task_enable(void)
5156 struct perf_event_context *ctx;
5157 struct perf_event *event;
5159 mutex_lock(¤t->perf_event_mutex);
5160 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5161 ctx = perf_event_ctx_lock(event);
5162 perf_event_for_each_child(event, _perf_event_enable);
5163 perf_event_ctx_unlock(event, ctx);
5165 mutex_unlock(¤t->perf_event_mutex);
5170 int perf_event_task_disable(void)
5172 struct perf_event_context *ctx;
5173 struct perf_event *event;
5175 mutex_lock(¤t->perf_event_mutex);
5176 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5177 ctx = perf_event_ctx_lock(event);
5178 perf_event_for_each_child(event, _perf_event_disable);
5179 perf_event_ctx_unlock(event, ctx);
5181 mutex_unlock(¤t->perf_event_mutex);
5186 static int perf_event_index(struct perf_event *event)
5188 if (event->hw.state & PERF_HES_STOPPED)
5191 if (event->state != PERF_EVENT_STATE_ACTIVE)
5194 return event->pmu->event_idx(event);
5197 static void calc_timer_values(struct perf_event *event,
5204 *now = perf_clock();
5205 ctx_time = event->shadow_ctx_time + *now;
5206 __perf_update_times(event, ctx_time, enabled, running);
5209 static void perf_event_init_userpage(struct perf_event *event)
5211 struct perf_event_mmap_page *userpg;
5212 struct ring_buffer *rb;
5215 rb = rcu_dereference(event->rb);
5219 userpg = rb->user_page;
5221 /* Allow new userspace to detect that bit 0 is deprecated */
5222 userpg->cap_bit0_is_deprecated = 1;
5223 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5224 userpg->data_offset = PAGE_SIZE;
5225 userpg->data_size = perf_data_size(rb);
5231 void __weak arch_perf_update_userpage(
5232 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5237 * Callers need to ensure there can be no nesting of this function, otherwise
5238 * the seqlock logic goes bad. We can not serialize this because the arch
5239 * code calls this from NMI context.
5241 void perf_event_update_userpage(struct perf_event *event)
5243 struct perf_event_mmap_page *userpg;
5244 struct ring_buffer *rb;
5245 u64 enabled, running, now;
5248 rb = rcu_dereference(event->rb);
5253 * compute total_time_enabled, total_time_running
5254 * based on snapshot values taken when the event
5255 * was last scheduled in.
5257 * we cannot simply called update_context_time()
5258 * because of locking issue as we can be called in
5261 calc_timer_values(event, &now, &enabled, &running);
5263 userpg = rb->user_page;
5265 * Disable preemption to guarantee consistent time stamps are stored to
5271 userpg->index = perf_event_index(event);
5272 userpg->offset = perf_event_count(event);
5274 userpg->offset -= local64_read(&event->hw.prev_count);
5276 userpg->time_enabled = enabled +
5277 atomic64_read(&event->child_total_time_enabled);
5279 userpg->time_running = running +
5280 atomic64_read(&event->child_total_time_running);
5282 arch_perf_update_userpage(event, userpg, now);
5290 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5292 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5294 struct perf_event *event = vmf->vma->vm_file->private_data;
5295 struct ring_buffer *rb;
5296 vm_fault_t ret = VM_FAULT_SIGBUS;
5298 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5299 if (vmf->pgoff == 0)
5305 rb = rcu_dereference(event->rb);
5309 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5312 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5316 get_page(vmf->page);
5317 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5318 vmf->page->index = vmf->pgoff;
5327 static void ring_buffer_attach(struct perf_event *event,
5328 struct ring_buffer *rb)
5330 struct ring_buffer *old_rb = NULL;
5331 unsigned long flags;
5335 * Should be impossible, we set this when removing
5336 * event->rb_entry and wait/clear when adding event->rb_entry.
5338 WARN_ON_ONCE(event->rcu_pending);
5341 spin_lock_irqsave(&old_rb->event_lock, flags);
5342 list_del_rcu(&event->rb_entry);
5343 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5345 event->rcu_batches = get_state_synchronize_rcu();
5346 event->rcu_pending = 1;
5350 if (event->rcu_pending) {
5351 cond_synchronize_rcu(event->rcu_batches);
5352 event->rcu_pending = 0;
5355 spin_lock_irqsave(&rb->event_lock, flags);
5356 list_add_rcu(&event->rb_entry, &rb->event_list);
5357 spin_unlock_irqrestore(&rb->event_lock, flags);
5361 * Avoid racing with perf_mmap_close(AUX): stop the event
5362 * before swizzling the event::rb pointer; if it's getting
5363 * unmapped, its aux_mmap_count will be 0 and it won't
5364 * restart. See the comment in __perf_pmu_output_stop().
5366 * Data will inevitably be lost when set_output is done in
5367 * mid-air, but then again, whoever does it like this is
5368 * not in for the data anyway.
5371 perf_event_stop(event, 0);
5373 rcu_assign_pointer(event->rb, rb);
5376 ring_buffer_put(old_rb);
5378 * Since we detached before setting the new rb, so that we
5379 * could attach the new rb, we could have missed a wakeup.
5382 wake_up_all(&event->waitq);
5386 static void ring_buffer_wakeup(struct perf_event *event)
5388 struct ring_buffer *rb;
5391 rb = rcu_dereference(event->rb);
5393 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5394 wake_up_all(&event->waitq);
5399 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5401 struct ring_buffer *rb;
5404 rb = rcu_dereference(event->rb);
5406 if (!refcount_inc_not_zero(&rb->refcount))
5414 void ring_buffer_put(struct ring_buffer *rb)
5416 if (!refcount_dec_and_test(&rb->refcount))
5419 WARN_ON_ONCE(!list_empty(&rb->event_list));
5421 call_rcu(&rb->rcu_head, rb_free_rcu);
5424 static void perf_mmap_open(struct vm_area_struct *vma)
5426 struct perf_event *event = vma->vm_file->private_data;
5428 atomic_inc(&event->mmap_count);
5429 atomic_inc(&event->rb->mmap_count);
5432 atomic_inc(&event->rb->aux_mmap_count);
5434 if (event->pmu->event_mapped)
5435 event->pmu->event_mapped(event, vma->vm_mm);
5438 static void perf_pmu_output_stop(struct perf_event *event);
5441 * A buffer can be mmap()ed multiple times; either directly through the same
5442 * event, or through other events by use of perf_event_set_output().
5444 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5445 * the buffer here, where we still have a VM context. This means we need
5446 * to detach all events redirecting to us.
5448 static void perf_mmap_close(struct vm_area_struct *vma)
5450 struct perf_event *event = vma->vm_file->private_data;
5452 struct ring_buffer *rb = ring_buffer_get(event);
5453 struct user_struct *mmap_user = rb->mmap_user;
5454 int mmap_locked = rb->mmap_locked;
5455 unsigned long size = perf_data_size(rb);
5457 if (event->pmu->event_unmapped)
5458 event->pmu->event_unmapped(event, vma->vm_mm);
5461 * rb->aux_mmap_count will always drop before rb->mmap_count and
5462 * event->mmap_count, so it is ok to use event->mmap_mutex to
5463 * serialize with perf_mmap here.
5465 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5466 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5468 * Stop all AUX events that are writing to this buffer,
5469 * so that we can free its AUX pages and corresponding PMU
5470 * data. Note that after rb::aux_mmap_count dropped to zero,
5471 * they won't start any more (see perf_aux_output_begin()).
5473 perf_pmu_output_stop(event);
5475 /* now it's safe to free the pages */
5476 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5477 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5479 /* this has to be the last one */
5481 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5483 mutex_unlock(&event->mmap_mutex);
5486 atomic_dec(&rb->mmap_count);
5488 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5491 ring_buffer_attach(event, NULL);
5492 mutex_unlock(&event->mmap_mutex);
5494 /* If there's still other mmap()s of this buffer, we're done. */
5495 if (atomic_read(&rb->mmap_count))
5499 * No other mmap()s, detach from all other events that might redirect
5500 * into the now unreachable buffer. Somewhat complicated by the
5501 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5505 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5506 if (!atomic_long_inc_not_zero(&event->refcount)) {
5508 * This event is en-route to free_event() which will
5509 * detach it and remove it from the list.
5515 mutex_lock(&event->mmap_mutex);
5517 * Check we didn't race with perf_event_set_output() which can
5518 * swizzle the rb from under us while we were waiting to
5519 * acquire mmap_mutex.
5521 * If we find a different rb; ignore this event, a next
5522 * iteration will no longer find it on the list. We have to
5523 * still restart the iteration to make sure we're not now
5524 * iterating the wrong list.
5526 if (event->rb == rb)
5527 ring_buffer_attach(event, NULL);
5529 mutex_unlock(&event->mmap_mutex);
5533 * Restart the iteration; either we're on the wrong list or
5534 * destroyed its integrity by doing a deletion.
5541 * It could be there's still a few 0-ref events on the list; they'll
5542 * get cleaned up by free_event() -- they'll also still have their
5543 * ref on the rb and will free it whenever they are done with it.
5545 * Aside from that, this buffer is 'fully' detached and unmapped,
5546 * undo the VM accounting.
5549 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5550 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5551 free_uid(mmap_user);
5554 ring_buffer_put(rb); /* could be last */
5557 static const struct vm_operations_struct perf_mmap_vmops = {
5558 .open = perf_mmap_open,
5559 .close = perf_mmap_close, /* non mergeable */
5560 .fault = perf_mmap_fault,
5561 .page_mkwrite = perf_mmap_fault,
5564 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5566 struct perf_event *event = file->private_data;
5567 unsigned long user_locked, user_lock_limit;
5568 struct user_struct *user = current_user();
5569 unsigned long locked, lock_limit;
5570 struct ring_buffer *rb = NULL;
5571 unsigned long vma_size;
5572 unsigned long nr_pages;
5573 long user_extra = 0, extra = 0;
5574 int ret = 0, flags = 0;
5577 * Don't allow mmap() of inherited per-task counters. This would
5578 * create a performance issue due to all children writing to the
5581 if (event->cpu == -1 && event->attr.inherit)
5584 if (!(vma->vm_flags & VM_SHARED))
5587 vma_size = vma->vm_end - vma->vm_start;
5589 if (vma->vm_pgoff == 0) {
5590 nr_pages = (vma_size / PAGE_SIZE) - 1;
5593 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5594 * mapped, all subsequent mappings should have the same size
5595 * and offset. Must be above the normal perf buffer.
5597 u64 aux_offset, aux_size;
5602 nr_pages = vma_size / PAGE_SIZE;
5604 mutex_lock(&event->mmap_mutex);
5611 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5612 aux_size = READ_ONCE(rb->user_page->aux_size);
5614 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5617 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5620 /* already mapped with a different offset */
5621 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5624 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5627 /* already mapped with a different size */
5628 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5631 if (!is_power_of_2(nr_pages))
5634 if (!atomic_inc_not_zero(&rb->mmap_count))
5637 if (rb_has_aux(rb)) {
5638 atomic_inc(&rb->aux_mmap_count);
5643 atomic_set(&rb->aux_mmap_count, 1);
5644 user_extra = nr_pages;
5650 * If we have rb pages ensure they're a power-of-two number, so we
5651 * can do bitmasks instead of modulo.
5653 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5656 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5659 WARN_ON_ONCE(event->ctx->parent_ctx);
5661 mutex_lock(&event->mmap_mutex);
5663 if (event->rb->nr_pages != nr_pages) {
5668 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5670 * Raced against perf_mmap_close() through
5671 * perf_event_set_output(). Try again, hope for better
5674 mutex_unlock(&event->mmap_mutex);
5681 user_extra = nr_pages + 1;
5684 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5687 * Increase the limit linearly with more CPUs:
5689 user_lock_limit *= num_online_cpus();
5691 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5693 if (user_locked > user_lock_limit)
5694 extra = user_locked - user_lock_limit;
5696 lock_limit = rlimit(RLIMIT_MEMLOCK);
5697 lock_limit >>= PAGE_SHIFT;
5698 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5700 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5701 !capable(CAP_IPC_LOCK)) {
5706 WARN_ON(!rb && event->rb);
5708 if (vma->vm_flags & VM_WRITE)
5709 flags |= RING_BUFFER_WRITABLE;
5712 rb = rb_alloc(nr_pages,
5713 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5721 atomic_set(&rb->mmap_count, 1);
5722 rb->mmap_user = get_current_user();
5723 rb->mmap_locked = extra;
5725 ring_buffer_attach(event, rb);
5727 perf_event_init_userpage(event);
5728 perf_event_update_userpage(event);
5730 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5731 event->attr.aux_watermark, flags);
5733 rb->aux_mmap_locked = extra;
5738 atomic_long_add(user_extra, &user->locked_vm);
5739 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5741 atomic_inc(&event->mmap_count);
5743 atomic_dec(&rb->mmap_count);
5746 mutex_unlock(&event->mmap_mutex);
5749 * Since pinned accounting is per vm we cannot allow fork() to copy our
5752 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5753 vma->vm_ops = &perf_mmap_vmops;
5755 if (event->pmu->event_mapped)
5756 event->pmu->event_mapped(event, vma->vm_mm);
5761 static int perf_fasync(int fd, struct file *filp, int on)
5763 struct inode *inode = file_inode(filp);
5764 struct perf_event *event = filp->private_data;
5768 retval = fasync_helper(fd, filp, on, &event->fasync);
5769 inode_unlock(inode);
5777 static const struct file_operations perf_fops = {
5778 .llseek = no_llseek,
5779 .release = perf_release,
5782 .unlocked_ioctl = perf_ioctl,
5783 .compat_ioctl = perf_compat_ioctl,
5785 .fasync = perf_fasync,
5791 * If there's data, ensure we set the poll() state and publish everything
5792 * to user-space before waking everybody up.
5795 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5797 /* only the parent has fasync state */
5799 event = event->parent;
5800 return &event->fasync;
5803 void perf_event_wakeup(struct perf_event *event)
5805 ring_buffer_wakeup(event);
5807 if (event->pending_kill) {
5808 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5809 event->pending_kill = 0;
5813 static void perf_pending_event(struct irq_work *entry)
5815 struct perf_event *event = container_of(entry,
5816 struct perf_event, pending);
5819 rctx = perf_swevent_get_recursion_context();
5821 * If we 'fail' here, that's OK, it means recursion is already disabled
5822 * and we won't recurse 'further'.
5825 if (event->pending_disable) {
5826 event->pending_disable = 0;
5827 perf_event_disable_local(event);
5830 if (event->pending_wakeup) {
5831 event->pending_wakeup = 0;
5832 perf_event_wakeup(event);
5836 perf_swevent_put_recursion_context(rctx);
5840 * We assume there is only KVM supporting the callbacks.
5841 * Later on, we might change it to a list if there is
5842 * another virtualization implementation supporting the callbacks.
5844 struct perf_guest_info_callbacks *perf_guest_cbs;
5846 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5848 perf_guest_cbs = cbs;
5851 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5853 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5855 perf_guest_cbs = NULL;
5858 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5861 perf_output_sample_regs(struct perf_output_handle *handle,
5862 struct pt_regs *regs, u64 mask)
5865 DECLARE_BITMAP(_mask, 64);
5867 bitmap_from_u64(_mask, mask);
5868 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5871 val = perf_reg_value(regs, bit);
5872 perf_output_put(handle, val);
5876 static void perf_sample_regs_user(struct perf_regs *regs_user,
5877 struct pt_regs *regs,
5878 struct pt_regs *regs_user_copy)
5880 if (user_mode(regs)) {
5881 regs_user->abi = perf_reg_abi(current);
5882 regs_user->regs = regs;
5883 } else if (current->mm) {
5884 perf_get_regs_user(regs_user, regs, regs_user_copy);
5886 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5887 regs_user->regs = NULL;
5891 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5892 struct pt_regs *regs)
5894 regs_intr->regs = regs;
5895 regs_intr->abi = perf_reg_abi(current);
5900 * Get remaining task size from user stack pointer.
5902 * It'd be better to take stack vma map and limit this more
5903 * precisly, but there's no way to get it safely under interrupt,
5904 * so using TASK_SIZE as limit.
5906 static u64 perf_ustack_task_size(struct pt_regs *regs)
5908 unsigned long addr = perf_user_stack_pointer(regs);
5910 if (!addr || addr >= TASK_SIZE)
5913 return TASK_SIZE - addr;
5917 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5918 struct pt_regs *regs)
5922 /* No regs, no stack pointer, no dump. */
5927 * Check if we fit in with the requested stack size into the:
5929 * If we don't, we limit the size to the TASK_SIZE.
5931 * - remaining sample size
5932 * If we don't, we customize the stack size to
5933 * fit in to the remaining sample size.
5936 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5937 stack_size = min(stack_size, (u16) task_size);
5939 /* Current header size plus static size and dynamic size. */
5940 header_size += 2 * sizeof(u64);
5942 /* Do we fit in with the current stack dump size? */
5943 if ((u16) (header_size + stack_size) < header_size) {
5945 * If we overflow the maximum size for the sample,
5946 * we customize the stack dump size to fit in.
5948 stack_size = USHRT_MAX - header_size - sizeof(u64);
5949 stack_size = round_up(stack_size, sizeof(u64));
5956 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5957 struct pt_regs *regs)
5959 /* Case of a kernel thread, nothing to dump */
5962 perf_output_put(handle, size);
5972 * - the size requested by user or the best one we can fit
5973 * in to the sample max size
5975 * - user stack dump data
5977 * - the actual dumped size
5981 perf_output_put(handle, dump_size);
5984 sp = perf_user_stack_pointer(regs);
5987 rem = __output_copy_user(handle, (void *) sp, dump_size);
5989 dyn_size = dump_size - rem;
5991 perf_output_skip(handle, rem);
5994 perf_output_put(handle, dyn_size);
5998 static void __perf_event_header__init_id(struct perf_event_header *header,
5999 struct perf_sample_data *data,
6000 struct perf_event *event)
6002 u64 sample_type = event->attr.sample_type;
6004 data->type = sample_type;
6005 header->size += event->id_header_size;
6007 if (sample_type & PERF_SAMPLE_TID) {
6008 /* namespace issues */
6009 data->tid_entry.pid = perf_event_pid(event, current);
6010 data->tid_entry.tid = perf_event_tid(event, current);
6013 if (sample_type & PERF_SAMPLE_TIME)
6014 data->time = perf_event_clock(event);
6016 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6017 data->id = primary_event_id(event);
6019 if (sample_type & PERF_SAMPLE_STREAM_ID)
6020 data->stream_id = event->id;
6022 if (sample_type & PERF_SAMPLE_CPU) {
6023 data->cpu_entry.cpu = raw_smp_processor_id();
6024 data->cpu_entry.reserved = 0;
6028 void perf_event_header__init_id(struct perf_event_header *header,
6029 struct perf_sample_data *data,
6030 struct perf_event *event)
6032 if (event->attr.sample_id_all)
6033 __perf_event_header__init_id(header, data, event);
6036 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6037 struct perf_sample_data *data)
6039 u64 sample_type = data->type;
6041 if (sample_type & PERF_SAMPLE_TID)
6042 perf_output_put(handle, data->tid_entry);
6044 if (sample_type & PERF_SAMPLE_TIME)
6045 perf_output_put(handle, data->time);
6047 if (sample_type & PERF_SAMPLE_ID)
6048 perf_output_put(handle, data->id);
6050 if (sample_type & PERF_SAMPLE_STREAM_ID)
6051 perf_output_put(handle, data->stream_id);
6053 if (sample_type & PERF_SAMPLE_CPU)
6054 perf_output_put(handle, data->cpu_entry);
6056 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6057 perf_output_put(handle, data->id);
6060 void perf_event__output_id_sample(struct perf_event *event,
6061 struct perf_output_handle *handle,
6062 struct perf_sample_data *sample)
6064 if (event->attr.sample_id_all)
6065 __perf_event__output_id_sample(handle, sample);
6068 static void perf_output_read_one(struct perf_output_handle *handle,
6069 struct perf_event *event,
6070 u64 enabled, u64 running)
6072 u64 read_format = event->attr.read_format;
6076 values[n++] = perf_event_count(event);
6077 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6078 values[n++] = enabled +
6079 atomic64_read(&event->child_total_time_enabled);
6081 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6082 values[n++] = running +
6083 atomic64_read(&event->child_total_time_running);
6085 if (read_format & PERF_FORMAT_ID)
6086 values[n++] = primary_event_id(event);
6088 __output_copy(handle, values, n * sizeof(u64));
6091 static void perf_output_read_group(struct perf_output_handle *handle,
6092 struct perf_event *event,
6093 u64 enabled, u64 running)
6095 struct perf_event *leader = event->group_leader, *sub;
6096 u64 read_format = event->attr.read_format;
6100 values[n++] = 1 + leader->nr_siblings;
6102 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6103 values[n++] = enabled;
6105 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6106 values[n++] = running;
6108 if ((leader != event) &&
6109 (leader->state == PERF_EVENT_STATE_ACTIVE))
6110 leader->pmu->read(leader);
6112 values[n++] = perf_event_count(leader);
6113 if (read_format & PERF_FORMAT_ID)
6114 values[n++] = primary_event_id(leader);
6116 __output_copy(handle, values, n * sizeof(u64));
6118 for_each_sibling_event(sub, leader) {
6121 if ((sub != event) &&
6122 (sub->state == PERF_EVENT_STATE_ACTIVE))
6123 sub->pmu->read(sub);
6125 values[n++] = perf_event_count(sub);
6126 if (read_format & PERF_FORMAT_ID)
6127 values[n++] = primary_event_id(sub);
6129 __output_copy(handle, values, n * sizeof(u64));
6133 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6134 PERF_FORMAT_TOTAL_TIME_RUNNING)
6137 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6139 * The problem is that its both hard and excessively expensive to iterate the
6140 * child list, not to mention that its impossible to IPI the children running
6141 * on another CPU, from interrupt/NMI context.
6143 static void perf_output_read(struct perf_output_handle *handle,
6144 struct perf_event *event)
6146 u64 enabled = 0, running = 0, now;
6147 u64 read_format = event->attr.read_format;
6150 * compute total_time_enabled, total_time_running
6151 * based on snapshot values taken when the event
6152 * was last scheduled in.
6154 * we cannot simply called update_context_time()
6155 * because of locking issue as we are called in
6158 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6159 calc_timer_values(event, &now, &enabled, &running);
6161 if (event->attr.read_format & PERF_FORMAT_GROUP)
6162 perf_output_read_group(handle, event, enabled, running);
6164 perf_output_read_one(handle, event, enabled, running);
6167 void perf_output_sample(struct perf_output_handle *handle,
6168 struct perf_event_header *header,
6169 struct perf_sample_data *data,
6170 struct perf_event *event)
6172 u64 sample_type = data->type;
6174 perf_output_put(handle, *header);
6176 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6177 perf_output_put(handle, data->id);
6179 if (sample_type & PERF_SAMPLE_IP)
6180 perf_output_put(handle, data->ip);
6182 if (sample_type & PERF_SAMPLE_TID)
6183 perf_output_put(handle, data->tid_entry);
6185 if (sample_type & PERF_SAMPLE_TIME)
6186 perf_output_put(handle, data->time);
6188 if (sample_type & PERF_SAMPLE_ADDR)
6189 perf_output_put(handle, data->addr);
6191 if (sample_type & PERF_SAMPLE_ID)
6192 perf_output_put(handle, data->id);
6194 if (sample_type & PERF_SAMPLE_STREAM_ID)
6195 perf_output_put(handle, data->stream_id);
6197 if (sample_type & PERF_SAMPLE_CPU)
6198 perf_output_put(handle, data->cpu_entry);
6200 if (sample_type & PERF_SAMPLE_PERIOD)
6201 perf_output_put(handle, data->period);
6203 if (sample_type & PERF_SAMPLE_READ)
6204 perf_output_read(handle, event);
6206 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6209 size += data->callchain->nr;
6210 size *= sizeof(u64);
6211 __output_copy(handle, data->callchain, size);
6214 if (sample_type & PERF_SAMPLE_RAW) {
6215 struct perf_raw_record *raw = data->raw;
6218 struct perf_raw_frag *frag = &raw->frag;
6220 perf_output_put(handle, raw->size);
6223 __output_custom(handle, frag->copy,
6224 frag->data, frag->size);
6226 __output_copy(handle, frag->data,
6229 if (perf_raw_frag_last(frag))
6234 __output_skip(handle, NULL, frag->pad);
6240 .size = sizeof(u32),
6243 perf_output_put(handle, raw);
6247 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6248 if (data->br_stack) {
6251 size = data->br_stack->nr
6252 * sizeof(struct perf_branch_entry);
6254 perf_output_put(handle, data->br_stack->nr);
6255 perf_output_copy(handle, data->br_stack->entries, size);
6258 * we always store at least the value of nr
6261 perf_output_put(handle, nr);
6265 if (sample_type & PERF_SAMPLE_REGS_USER) {
6266 u64 abi = data->regs_user.abi;
6269 * If there are no regs to dump, notice it through
6270 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6272 perf_output_put(handle, abi);
6275 u64 mask = event->attr.sample_regs_user;
6276 perf_output_sample_regs(handle,
6277 data->regs_user.regs,
6282 if (sample_type & PERF_SAMPLE_STACK_USER) {
6283 perf_output_sample_ustack(handle,
6284 data->stack_user_size,
6285 data->regs_user.regs);
6288 if (sample_type & PERF_SAMPLE_WEIGHT)
6289 perf_output_put(handle, data->weight);
6291 if (sample_type & PERF_SAMPLE_DATA_SRC)
6292 perf_output_put(handle, data->data_src.val);
6294 if (sample_type & PERF_SAMPLE_TRANSACTION)
6295 perf_output_put(handle, data->txn);
6297 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6298 u64 abi = data->regs_intr.abi;
6300 * If there are no regs to dump, notice it through
6301 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6303 perf_output_put(handle, abi);
6306 u64 mask = event->attr.sample_regs_intr;
6308 perf_output_sample_regs(handle,
6309 data->regs_intr.regs,
6314 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6315 perf_output_put(handle, data->phys_addr);
6317 if (!event->attr.watermark) {
6318 int wakeup_events = event->attr.wakeup_events;
6320 if (wakeup_events) {
6321 struct ring_buffer *rb = handle->rb;
6322 int events = local_inc_return(&rb->events);
6324 if (events >= wakeup_events) {
6325 local_sub(wakeup_events, &rb->events);
6326 local_inc(&rb->wakeup);
6332 static u64 perf_virt_to_phys(u64 virt)
6335 struct page *p = NULL;
6340 if (virt >= TASK_SIZE) {
6341 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6342 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6343 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6344 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6347 * Walking the pages tables for user address.
6348 * Interrupts are disabled, so it prevents any tear down
6349 * of the page tables.
6350 * Try IRQ-safe __get_user_pages_fast first.
6351 * If failed, leave phys_addr as 0.
6353 if ((current->mm != NULL) &&
6354 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6355 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6364 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6366 struct perf_callchain_entry *
6367 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6369 bool kernel = !event->attr.exclude_callchain_kernel;
6370 bool user = !event->attr.exclude_callchain_user;
6371 /* Disallow cross-task user callchains. */
6372 bool crosstask = event->ctx->task && event->ctx->task != current;
6373 const u32 max_stack = event->attr.sample_max_stack;
6374 struct perf_callchain_entry *callchain;
6376 if (!kernel && !user)
6377 return &__empty_callchain;
6379 callchain = get_perf_callchain(regs, 0, kernel, user,
6380 max_stack, crosstask, true);
6381 return callchain ?: &__empty_callchain;
6384 void perf_prepare_sample(struct perf_event_header *header,
6385 struct perf_sample_data *data,
6386 struct perf_event *event,
6387 struct pt_regs *regs)
6389 u64 sample_type = event->attr.sample_type;
6391 header->type = PERF_RECORD_SAMPLE;
6392 header->size = sizeof(*header) + event->header_size;
6395 header->misc |= perf_misc_flags(regs);
6397 __perf_event_header__init_id(header, data, event);
6399 if (sample_type & PERF_SAMPLE_IP)
6400 data->ip = perf_instruction_pointer(regs);
6402 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6405 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6406 data->callchain = perf_callchain(event, regs);
6408 size += data->callchain->nr;
6410 header->size += size * sizeof(u64);
6413 if (sample_type & PERF_SAMPLE_RAW) {
6414 struct perf_raw_record *raw = data->raw;
6418 struct perf_raw_frag *frag = &raw->frag;
6423 if (perf_raw_frag_last(frag))
6428 size = round_up(sum + sizeof(u32), sizeof(u64));
6429 raw->size = size - sizeof(u32);
6430 frag->pad = raw->size - sum;
6435 header->size += size;
6438 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6439 int size = sizeof(u64); /* nr */
6440 if (data->br_stack) {
6441 size += data->br_stack->nr
6442 * sizeof(struct perf_branch_entry);
6444 header->size += size;
6447 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6448 perf_sample_regs_user(&data->regs_user, regs,
6449 &data->regs_user_copy);
6451 if (sample_type & PERF_SAMPLE_REGS_USER) {
6452 /* regs dump ABI info */
6453 int size = sizeof(u64);
6455 if (data->regs_user.regs) {
6456 u64 mask = event->attr.sample_regs_user;
6457 size += hweight64(mask) * sizeof(u64);
6460 header->size += size;
6463 if (sample_type & PERF_SAMPLE_STACK_USER) {
6465 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6466 * processed as the last one or have additional check added
6467 * in case new sample type is added, because we could eat
6468 * up the rest of the sample size.
6470 u16 stack_size = event->attr.sample_stack_user;
6471 u16 size = sizeof(u64);
6473 stack_size = perf_sample_ustack_size(stack_size, header->size,
6474 data->regs_user.regs);
6477 * If there is something to dump, add space for the dump
6478 * itself and for the field that tells the dynamic size,
6479 * which is how many have been actually dumped.
6482 size += sizeof(u64) + stack_size;
6484 data->stack_user_size = stack_size;
6485 header->size += size;
6488 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6489 /* regs dump ABI info */
6490 int size = sizeof(u64);
6492 perf_sample_regs_intr(&data->regs_intr, regs);
6494 if (data->regs_intr.regs) {
6495 u64 mask = event->attr.sample_regs_intr;
6497 size += hweight64(mask) * sizeof(u64);
6500 header->size += size;
6503 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6504 data->phys_addr = perf_virt_to_phys(data->addr);
6507 static __always_inline int
6508 __perf_event_output(struct perf_event *event,
6509 struct perf_sample_data *data,
6510 struct pt_regs *regs,
6511 int (*output_begin)(struct perf_output_handle *,
6512 struct perf_event *,
6515 struct perf_output_handle handle;
6516 struct perf_event_header header;
6519 /* protect the callchain buffers */
6522 perf_prepare_sample(&header, data, event, regs);
6524 err = output_begin(&handle, event, header.size);
6528 perf_output_sample(&handle, &header, data, event);
6530 perf_output_end(&handle);
6538 perf_event_output_forward(struct perf_event *event,
6539 struct perf_sample_data *data,
6540 struct pt_regs *regs)
6542 __perf_event_output(event, data, regs, perf_output_begin_forward);
6546 perf_event_output_backward(struct perf_event *event,
6547 struct perf_sample_data *data,
6548 struct pt_regs *regs)
6550 __perf_event_output(event, data, regs, perf_output_begin_backward);
6554 perf_event_output(struct perf_event *event,
6555 struct perf_sample_data *data,
6556 struct pt_regs *regs)
6558 return __perf_event_output(event, data, regs, perf_output_begin);
6565 struct perf_read_event {
6566 struct perf_event_header header;
6573 perf_event_read_event(struct perf_event *event,
6574 struct task_struct *task)
6576 struct perf_output_handle handle;
6577 struct perf_sample_data sample;
6578 struct perf_read_event read_event = {
6580 .type = PERF_RECORD_READ,
6582 .size = sizeof(read_event) + event->read_size,
6584 .pid = perf_event_pid(event, task),
6585 .tid = perf_event_tid(event, task),
6589 perf_event_header__init_id(&read_event.header, &sample, event);
6590 ret = perf_output_begin(&handle, event, read_event.header.size);
6594 perf_output_put(&handle, read_event);
6595 perf_output_read(&handle, event);
6596 perf_event__output_id_sample(event, &handle, &sample);
6598 perf_output_end(&handle);
6601 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6604 perf_iterate_ctx(struct perf_event_context *ctx,
6605 perf_iterate_f output,
6606 void *data, bool all)
6608 struct perf_event *event;
6610 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6612 if (event->state < PERF_EVENT_STATE_INACTIVE)
6614 if (!event_filter_match(event))
6618 output(event, data);
6622 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6624 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6625 struct perf_event *event;
6627 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6629 * Skip events that are not fully formed yet; ensure that
6630 * if we observe event->ctx, both event and ctx will be
6631 * complete enough. See perf_install_in_context().
6633 if (!smp_load_acquire(&event->ctx))
6636 if (event->state < PERF_EVENT_STATE_INACTIVE)
6638 if (!event_filter_match(event))
6640 output(event, data);
6645 * Iterate all events that need to receive side-band events.
6647 * For new callers; ensure that account_pmu_sb_event() includes
6648 * your event, otherwise it might not get delivered.
6651 perf_iterate_sb(perf_iterate_f output, void *data,
6652 struct perf_event_context *task_ctx)
6654 struct perf_event_context *ctx;
6661 * If we have task_ctx != NULL we only notify the task context itself.
6662 * The task_ctx is set only for EXIT events before releasing task
6666 perf_iterate_ctx(task_ctx, output, data, false);
6670 perf_iterate_sb_cpu(output, data);
6672 for_each_task_context_nr(ctxn) {
6673 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6675 perf_iterate_ctx(ctx, output, data, false);
6683 * Clear all file-based filters at exec, they'll have to be
6684 * re-instated when/if these objects are mmapped again.
6686 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6688 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6689 struct perf_addr_filter *filter;
6690 unsigned int restart = 0, count = 0;
6691 unsigned long flags;
6693 if (!has_addr_filter(event))
6696 raw_spin_lock_irqsave(&ifh->lock, flags);
6697 list_for_each_entry(filter, &ifh->list, entry) {
6698 if (filter->path.dentry) {
6699 event->addr_filter_ranges[count].start = 0;
6700 event->addr_filter_ranges[count].size = 0;
6708 event->addr_filters_gen++;
6709 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6712 perf_event_stop(event, 1);
6715 void perf_event_exec(void)
6717 struct perf_event_context *ctx;
6721 for_each_task_context_nr(ctxn) {
6722 ctx = current->perf_event_ctxp[ctxn];
6726 perf_event_enable_on_exec(ctxn);
6728 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6734 struct remote_output {
6735 struct ring_buffer *rb;
6739 static void __perf_event_output_stop(struct perf_event *event, void *data)
6741 struct perf_event *parent = event->parent;
6742 struct remote_output *ro = data;
6743 struct ring_buffer *rb = ro->rb;
6744 struct stop_event_data sd = {
6748 if (!has_aux(event))
6755 * In case of inheritance, it will be the parent that links to the
6756 * ring-buffer, but it will be the child that's actually using it.
6758 * We are using event::rb to determine if the event should be stopped,
6759 * however this may race with ring_buffer_attach() (through set_output),
6760 * which will make us skip the event that actually needs to be stopped.
6761 * So ring_buffer_attach() has to stop an aux event before re-assigning
6764 if (rcu_dereference(parent->rb) == rb)
6765 ro->err = __perf_event_stop(&sd);
6768 static int __perf_pmu_output_stop(void *info)
6770 struct perf_event *event = info;
6771 struct pmu *pmu = event->pmu;
6772 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6773 struct remote_output ro = {
6778 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6779 if (cpuctx->task_ctx)
6780 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6787 static void perf_pmu_output_stop(struct perf_event *event)
6789 struct perf_event *iter;
6794 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6796 * For per-CPU events, we need to make sure that neither they
6797 * nor their children are running; for cpu==-1 events it's
6798 * sufficient to stop the event itself if it's active, since
6799 * it can't have children.
6803 cpu = READ_ONCE(iter->oncpu);
6808 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6809 if (err == -EAGAIN) {
6818 * task tracking -- fork/exit
6820 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6823 struct perf_task_event {
6824 struct task_struct *task;
6825 struct perf_event_context *task_ctx;
6828 struct perf_event_header header;
6838 static int perf_event_task_match(struct perf_event *event)
6840 return event->attr.comm || event->attr.mmap ||
6841 event->attr.mmap2 || event->attr.mmap_data ||
6845 static void perf_event_task_output(struct perf_event *event,
6848 struct perf_task_event *task_event = data;
6849 struct perf_output_handle handle;
6850 struct perf_sample_data sample;
6851 struct task_struct *task = task_event->task;
6852 int ret, size = task_event->event_id.header.size;
6854 if (!perf_event_task_match(event))
6857 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6859 ret = perf_output_begin(&handle, event,
6860 task_event->event_id.header.size);
6864 task_event->event_id.pid = perf_event_pid(event, task);
6865 task_event->event_id.ppid = perf_event_pid(event, current);
6867 task_event->event_id.tid = perf_event_tid(event, task);
6868 task_event->event_id.ptid = perf_event_tid(event, current);
6870 task_event->event_id.time = perf_event_clock(event);
6872 perf_output_put(&handle, task_event->event_id);
6874 perf_event__output_id_sample(event, &handle, &sample);
6876 perf_output_end(&handle);
6878 task_event->event_id.header.size = size;
6881 static void perf_event_task(struct task_struct *task,
6882 struct perf_event_context *task_ctx,
6885 struct perf_task_event task_event;
6887 if (!atomic_read(&nr_comm_events) &&
6888 !atomic_read(&nr_mmap_events) &&
6889 !atomic_read(&nr_task_events))
6892 task_event = (struct perf_task_event){
6894 .task_ctx = task_ctx,
6897 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6899 .size = sizeof(task_event.event_id),
6909 perf_iterate_sb(perf_event_task_output,
6914 void perf_event_fork(struct task_struct *task)
6916 perf_event_task(task, NULL, 1);
6917 perf_event_namespaces(task);
6924 struct perf_comm_event {
6925 struct task_struct *task;
6930 struct perf_event_header header;
6937 static int perf_event_comm_match(struct perf_event *event)
6939 return event->attr.comm;
6942 static void perf_event_comm_output(struct perf_event *event,
6945 struct perf_comm_event *comm_event = data;
6946 struct perf_output_handle handle;
6947 struct perf_sample_data sample;
6948 int size = comm_event->event_id.header.size;
6951 if (!perf_event_comm_match(event))
6954 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6955 ret = perf_output_begin(&handle, event,
6956 comm_event->event_id.header.size);
6961 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6962 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6964 perf_output_put(&handle, comm_event->event_id);
6965 __output_copy(&handle, comm_event->comm,
6966 comm_event->comm_size);
6968 perf_event__output_id_sample(event, &handle, &sample);
6970 perf_output_end(&handle);
6972 comm_event->event_id.header.size = size;
6975 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6977 char comm[TASK_COMM_LEN];
6980 memset(comm, 0, sizeof(comm));
6981 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6982 size = ALIGN(strlen(comm)+1, sizeof(u64));
6984 comm_event->comm = comm;
6985 comm_event->comm_size = size;
6987 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6989 perf_iterate_sb(perf_event_comm_output,
6994 void perf_event_comm(struct task_struct *task, bool exec)
6996 struct perf_comm_event comm_event;
6998 if (!atomic_read(&nr_comm_events))
7001 comm_event = (struct perf_comm_event){
7007 .type = PERF_RECORD_COMM,
7008 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7016 perf_event_comm_event(&comm_event);
7020 * namespaces tracking
7023 struct perf_namespaces_event {
7024 struct task_struct *task;
7027 struct perf_event_header header;
7032 struct perf_ns_link_info link_info[NR_NAMESPACES];
7036 static int perf_event_namespaces_match(struct perf_event *event)
7038 return event->attr.namespaces;
7041 static void perf_event_namespaces_output(struct perf_event *event,
7044 struct perf_namespaces_event *namespaces_event = data;
7045 struct perf_output_handle handle;
7046 struct perf_sample_data sample;
7047 u16 header_size = namespaces_event->event_id.header.size;
7050 if (!perf_event_namespaces_match(event))
7053 perf_event_header__init_id(&namespaces_event->event_id.header,
7055 ret = perf_output_begin(&handle, event,
7056 namespaces_event->event_id.header.size);
7060 namespaces_event->event_id.pid = perf_event_pid(event,
7061 namespaces_event->task);
7062 namespaces_event->event_id.tid = perf_event_tid(event,
7063 namespaces_event->task);
7065 perf_output_put(&handle, namespaces_event->event_id);
7067 perf_event__output_id_sample(event, &handle, &sample);
7069 perf_output_end(&handle);
7071 namespaces_event->event_id.header.size = header_size;
7074 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7075 struct task_struct *task,
7076 const struct proc_ns_operations *ns_ops)
7078 struct path ns_path;
7079 struct inode *ns_inode;
7082 error = ns_get_path(&ns_path, task, ns_ops);
7084 ns_inode = ns_path.dentry->d_inode;
7085 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7086 ns_link_info->ino = ns_inode->i_ino;
7091 void perf_event_namespaces(struct task_struct *task)
7093 struct perf_namespaces_event namespaces_event;
7094 struct perf_ns_link_info *ns_link_info;
7096 if (!atomic_read(&nr_namespaces_events))
7099 namespaces_event = (struct perf_namespaces_event){
7103 .type = PERF_RECORD_NAMESPACES,
7105 .size = sizeof(namespaces_event.event_id),
7109 .nr_namespaces = NR_NAMESPACES,
7110 /* .link_info[NR_NAMESPACES] */
7114 ns_link_info = namespaces_event.event_id.link_info;
7116 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7117 task, &mntns_operations);
7119 #ifdef CONFIG_USER_NS
7120 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7121 task, &userns_operations);
7123 #ifdef CONFIG_NET_NS
7124 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7125 task, &netns_operations);
7127 #ifdef CONFIG_UTS_NS
7128 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7129 task, &utsns_operations);
7131 #ifdef CONFIG_IPC_NS
7132 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7133 task, &ipcns_operations);
7135 #ifdef CONFIG_PID_NS
7136 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7137 task, &pidns_operations);
7139 #ifdef CONFIG_CGROUPS
7140 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7141 task, &cgroupns_operations);
7144 perf_iterate_sb(perf_event_namespaces_output,
7153 struct perf_mmap_event {
7154 struct vm_area_struct *vma;
7156 const char *file_name;
7164 struct perf_event_header header;
7174 static int perf_event_mmap_match(struct perf_event *event,
7177 struct perf_mmap_event *mmap_event = data;
7178 struct vm_area_struct *vma = mmap_event->vma;
7179 int executable = vma->vm_flags & VM_EXEC;
7181 return (!executable && event->attr.mmap_data) ||
7182 (executable && (event->attr.mmap || event->attr.mmap2));
7185 static void perf_event_mmap_output(struct perf_event *event,
7188 struct perf_mmap_event *mmap_event = data;
7189 struct perf_output_handle handle;
7190 struct perf_sample_data sample;
7191 int size = mmap_event->event_id.header.size;
7192 u32 type = mmap_event->event_id.header.type;
7195 if (!perf_event_mmap_match(event, data))
7198 if (event->attr.mmap2) {
7199 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7200 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7201 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7202 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7203 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7204 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7205 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7208 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7209 ret = perf_output_begin(&handle, event,
7210 mmap_event->event_id.header.size);
7214 mmap_event->event_id.pid = perf_event_pid(event, current);
7215 mmap_event->event_id.tid = perf_event_tid(event, current);
7217 perf_output_put(&handle, mmap_event->event_id);
7219 if (event->attr.mmap2) {
7220 perf_output_put(&handle, mmap_event->maj);
7221 perf_output_put(&handle, mmap_event->min);
7222 perf_output_put(&handle, mmap_event->ino);
7223 perf_output_put(&handle, mmap_event->ino_generation);
7224 perf_output_put(&handle, mmap_event->prot);
7225 perf_output_put(&handle, mmap_event->flags);
7228 __output_copy(&handle, mmap_event->file_name,
7229 mmap_event->file_size);
7231 perf_event__output_id_sample(event, &handle, &sample);
7233 perf_output_end(&handle);
7235 mmap_event->event_id.header.size = size;
7236 mmap_event->event_id.header.type = type;
7239 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7241 struct vm_area_struct *vma = mmap_event->vma;
7242 struct file *file = vma->vm_file;
7243 int maj = 0, min = 0;
7244 u64 ino = 0, gen = 0;
7245 u32 prot = 0, flags = 0;
7251 if (vma->vm_flags & VM_READ)
7253 if (vma->vm_flags & VM_WRITE)
7255 if (vma->vm_flags & VM_EXEC)
7258 if (vma->vm_flags & VM_MAYSHARE)
7261 flags = MAP_PRIVATE;
7263 if (vma->vm_flags & VM_DENYWRITE)
7264 flags |= MAP_DENYWRITE;
7265 if (vma->vm_flags & VM_MAYEXEC)
7266 flags |= MAP_EXECUTABLE;
7267 if (vma->vm_flags & VM_LOCKED)
7268 flags |= MAP_LOCKED;
7269 if (vma->vm_flags & VM_HUGETLB)
7270 flags |= MAP_HUGETLB;
7273 struct inode *inode;
7276 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7282 * d_path() works from the end of the rb backwards, so we
7283 * need to add enough zero bytes after the string to handle
7284 * the 64bit alignment we do later.
7286 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7291 inode = file_inode(vma->vm_file);
7292 dev = inode->i_sb->s_dev;
7294 gen = inode->i_generation;
7300 if (vma->vm_ops && vma->vm_ops->name) {
7301 name = (char *) vma->vm_ops->name(vma);
7306 name = (char *)arch_vma_name(vma);
7310 if (vma->vm_start <= vma->vm_mm->start_brk &&
7311 vma->vm_end >= vma->vm_mm->brk) {
7315 if (vma->vm_start <= vma->vm_mm->start_stack &&
7316 vma->vm_end >= vma->vm_mm->start_stack) {
7326 strlcpy(tmp, name, sizeof(tmp));
7330 * Since our buffer works in 8 byte units we need to align our string
7331 * size to a multiple of 8. However, we must guarantee the tail end is
7332 * zero'd out to avoid leaking random bits to userspace.
7334 size = strlen(name)+1;
7335 while (!IS_ALIGNED(size, sizeof(u64)))
7336 name[size++] = '\0';
7338 mmap_event->file_name = name;
7339 mmap_event->file_size = size;
7340 mmap_event->maj = maj;
7341 mmap_event->min = min;
7342 mmap_event->ino = ino;
7343 mmap_event->ino_generation = gen;
7344 mmap_event->prot = prot;
7345 mmap_event->flags = flags;
7347 if (!(vma->vm_flags & VM_EXEC))
7348 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7350 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7352 perf_iterate_sb(perf_event_mmap_output,
7360 * Check whether inode and address range match filter criteria.
7362 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7363 struct file *file, unsigned long offset,
7366 /* d_inode(NULL) won't be equal to any mapped user-space file */
7367 if (!filter->path.dentry)
7370 if (d_inode(filter->path.dentry) != file_inode(file))
7373 if (filter->offset > offset + size)
7376 if (filter->offset + filter->size < offset)
7382 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7383 struct vm_area_struct *vma,
7384 struct perf_addr_filter_range *fr)
7386 unsigned long vma_size = vma->vm_end - vma->vm_start;
7387 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7388 struct file *file = vma->vm_file;
7390 if (!perf_addr_filter_match(filter, file, off, vma_size))
7393 if (filter->offset < off) {
7394 fr->start = vma->vm_start;
7395 fr->size = min(vma_size, filter->size - (off - filter->offset));
7397 fr->start = vma->vm_start + filter->offset - off;
7398 fr->size = min(vma->vm_end - fr->start, filter->size);
7404 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7406 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7407 struct vm_area_struct *vma = data;
7408 struct perf_addr_filter *filter;
7409 unsigned int restart = 0, count = 0;
7410 unsigned long flags;
7412 if (!has_addr_filter(event))
7418 raw_spin_lock_irqsave(&ifh->lock, flags);
7419 list_for_each_entry(filter, &ifh->list, entry) {
7420 if (perf_addr_filter_vma_adjust(filter, vma,
7421 &event->addr_filter_ranges[count]))
7428 event->addr_filters_gen++;
7429 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7432 perf_event_stop(event, 1);
7436 * Adjust all task's events' filters to the new vma
7438 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7440 struct perf_event_context *ctx;
7444 * Data tracing isn't supported yet and as such there is no need
7445 * to keep track of anything that isn't related to executable code:
7447 if (!(vma->vm_flags & VM_EXEC))
7451 for_each_task_context_nr(ctxn) {
7452 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7456 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7461 void perf_event_mmap(struct vm_area_struct *vma)
7463 struct perf_mmap_event mmap_event;
7465 if (!atomic_read(&nr_mmap_events))
7468 mmap_event = (struct perf_mmap_event){
7474 .type = PERF_RECORD_MMAP,
7475 .misc = PERF_RECORD_MISC_USER,
7480 .start = vma->vm_start,
7481 .len = vma->vm_end - vma->vm_start,
7482 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7484 /* .maj (attr_mmap2 only) */
7485 /* .min (attr_mmap2 only) */
7486 /* .ino (attr_mmap2 only) */
7487 /* .ino_generation (attr_mmap2 only) */
7488 /* .prot (attr_mmap2 only) */
7489 /* .flags (attr_mmap2 only) */
7492 perf_addr_filters_adjust(vma);
7493 perf_event_mmap_event(&mmap_event);
7496 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7497 unsigned long size, u64 flags)
7499 struct perf_output_handle handle;
7500 struct perf_sample_data sample;
7501 struct perf_aux_event {
7502 struct perf_event_header header;
7508 .type = PERF_RECORD_AUX,
7510 .size = sizeof(rec),
7518 perf_event_header__init_id(&rec.header, &sample, event);
7519 ret = perf_output_begin(&handle, event, rec.header.size);
7524 perf_output_put(&handle, rec);
7525 perf_event__output_id_sample(event, &handle, &sample);
7527 perf_output_end(&handle);
7531 * Lost/dropped samples logging
7533 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7535 struct perf_output_handle handle;
7536 struct perf_sample_data sample;
7540 struct perf_event_header header;
7542 } lost_samples_event = {
7544 .type = PERF_RECORD_LOST_SAMPLES,
7546 .size = sizeof(lost_samples_event),
7551 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7553 ret = perf_output_begin(&handle, event,
7554 lost_samples_event.header.size);
7558 perf_output_put(&handle, lost_samples_event);
7559 perf_event__output_id_sample(event, &handle, &sample);
7560 perf_output_end(&handle);
7564 * context_switch tracking
7567 struct perf_switch_event {
7568 struct task_struct *task;
7569 struct task_struct *next_prev;
7572 struct perf_event_header header;
7578 static int perf_event_switch_match(struct perf_event *event)
7580 return event->attr.context_switch;
7583 static void perf_event_switch_output(struct perf_event *event, void *data)
7585 struct perf_switch_event *se = data;
7586 struct perf_output_handle handle;
7587 struct perf_sample_data sample;
7590 if (!perf_event_switch_match(event))
7593 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7594 if (event->ctx->task) {
7595 se->event_id.header.type = PERF_RECORD_SWITCH;
7596 se->event_id.header.size = sizeof(se->event_id.header);
7598 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7599 se->event_id.header.size = sizeof(se->event_id);
7600 se->event_id.next_prev_pid =
7601 perf_event_pid(event, se->next_prev);
7602 se->event_id.next_prev_tid =
7603 perf_event_tid(event, se->next_prev);
7606 perf_event_header__init_id(&se->event_id.header, &sample, event);
7608 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7612 if (event->ctx->task)
7613 perf_output_put(&handle, se->event_id.header);
7615 perf_output_put(&handle, se->event_id);
7617 perf_event__output_id_sample(event, &handle, &sample);
7619 perf_output_end(&handle);
7622 static void perf_event_switch(struct task_struct *task,
7623 struct task_struct *next_prev, bool sched_in)
7625 struct perf_switch_event switch_event;
7627 /* N.B. caller checks nr_switch_events != 0 */
7629 switch_event = (struct perf_switch_event){
7631 .next_prev = next_prev,
7635 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7638 /* .next_prev_pid */
7639 /* .next_prev_tid */
7643 if (!sched_in && task->state == TASK_RUNNING)
7644 switch_event.event_id.header.misc |=
7645 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7647 perf_iterate_sb(perf_event_switch_output,
7653 * IRQ throttle logging
7656 static void perf_log_throttle(struct perf_event *event, int enable)
7658 struct perf_output_handle handle;
7659 struct perf_sample_data sample;
7663 struct perf_event_header header;
7667 } throttle_event = {
7669 .type = PERF_RECORD_THROTTLE,
7671 .size = sizeof(throttle_event),
7673 .time = perf_event_clock(event),
7674 .id = primary_event_id(event),
7675 .stream_id = event->id,
7679 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7681 perf_event_header__init_id(&throttle_event.header, &sample, event);
7683 ret = perf_output_begin(&handle, event,
7684 throttle_event.header.size);
7688 perf_output_put(&handle, throttle_event);
7689 perf_event__output_id_sample(event, &handle, &sample);
7690 perf_output_end(&handle);
7694 * ksymbol register/unregister tracking
7697 struct perf_ksymbol_event {
7701 struct perf_event_header header;
7709 static int perf_event_ksymbol_match(struct perf_event *event)
7711 return event->attr.ksymbol;
7714 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7716 struct perf_ksymbol_event *ksymbol_event = data;
7717 struct perf_output_handle handle;
7718 struct perf_sample_data sample;
7721 if (!perf_event_ksymbol_match(event))
7724 perf_event_header__init_id(&ksymbol_event->event_id.header,
7726 ret = perf_output_begin(&handle, event,
7727 ksymbol_event->event_id.header.size);
7731 perf_output_put(&handle, ksymbol_event->event_id);
7732 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7733 perf_event__output_id_sample(event, &handle, &sample);
7735 perf_output_end(&handle);
7738 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7741 struct perf_ksymbol_event ksymbol_event;
7742 char name[KSYM_NAME_LEN];
7746 if (!atomic_read(&nr_ksymbol_events))
7749 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7750 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7753 strlcpy(name, sym, KSYM_NAME_LEN);
7754 name_len = strlen(name) + 1;
7755 while (!IS_ALIGNED(name_len, sizeof(u64)))
7756 name[name_len++] = '\0';
7757 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7760 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7762 ksymbol_event = (struct perf_ksymbol_event){
7764 .name_len = name_len,
7767 .type = PERF_RECORD_KSYMBOL,
7768 .size = sizeof(ksymbol_event.event_id) +
7773 .ksym_type = ksym_type,
7778 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7781 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7785 * bpf program load/unload tracking
7788 struct perf_bpf_event {
7789 struct bpf_prog *prog;
7791 struct perf_event_header header;
7795 u8 tag[BPF_TAG_SIZE];
7799 static int perf_event_bpf_match(struct perf_event *event)
7801 return event->attr.bpf_event;
7804 static void perf_event_bpf_output(struct perf_event *event, void *data)
7806 struct perf_bpf_event *bpf_event = data;
7807 struct perf_output_handle handle;
7808 struct perf_sample_data sample;
7811 if (!perf_event_bpf_match(event))
7814 perf_event_header__init_id(&bpf_event->event_id.header,
7816 ret = perf_output_begin(&handle, event,
7817 bpf_event->event_id.header.size);
7821 perf_output_put(&handle, bpf_event->event_id);
7822 perf_event__output_id_sample(event, &handle, &sample);
7824 perf_output_end(&handle);
7827 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
7828 enum perf_bpf_event_type type)
7830 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
7831 char sym[KSYM_NAME_LEN];
7834 if (prog->aux->func_cnt == 0) {
7835 bpf_get_prog_name(prog, sym);
7836 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
7837 (u64)(unsigned long)prog->bpf_func,
7838 prog->jited_len, unregister, sym);
7840 for (i = 0; i < prog->aux->func_cnt; i++) {
7841 struct bpf_prog *subprog = prog->aux->func[i];
7843 bpf_get_prog_name(subprog, sym);
7845 PERF_RECORD_KSYMBOL_TYPE_BPF,
7846 (u64)(unsigned long)subprog->bpf_func,
7847 subprog->jited_len, unregister, sym);
7852 void perf_event_bpf_event(struct bpf_prog *prog,
7853 enum perf_bpf_event_type type,
7856 struct perf_bpf_event bpf_event;
7858 if (type <= PERF_BPF_EVENT_UNKNOWN ||
7859 type >= PERF_BPF_EVENT_MAX)
7863 case PERF_BPF_EVENT_PROG_LOAD:
7864 case PERF_BPF_EVENT_PROG_UNLOAD:
7865 if (atomic_read(&nr_ksymbol_events))
7866 perf_event_bpf_emit_ksymbols(prog, type);
7872 if (!atomic_read(&nr_bpf_events))
7875 bpf_event = (struct perf_bpf_event){
7879 .type = PERF_RECORD_BPF_EVENT,
7880 .size = sizeof(bpf_event.event_id),
7884 .id = prog->aux->id,
7888 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
7890 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
7891 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
7894 void perf_event_itrace_started(struct perf_event *event)
7896 event->attach_state |= PERF_ATTACH_ITRACE;
7899 static void perf_log_itrace_start(struct perf_event *event)
7901 struct perf_output_handle handle;
7902 struct perf_sample_data sample;
7903 struct perf_aux_event {
7904 struct perf_event_header header;
7911 event = event->parent;
7913 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7914 event->attach_state & PERF_ATTACH_ITRACE)
7917 rec.header.type = PERF_RECORD_ITRACE_START;
7918 rec.header.misc = 0;
7919 rec.header.size = sizeof(rec);
7920 rec.pid = perf_event_pid(event, current);
7921 rec.tid = perf_event_tid(event, current);
7923 perf_event_header__init_id(&rec.header, &sample, event);
7924 ret = perf_output_begin(&handle, event, rec.header.size);
7929 perf_output_put(&handle, rec);
7930 perf_event__output_id_sample(event, &handle, &sample);
7932 perf_output_end(&handle);
7936 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7938 struct hw_perf_event *hwc = &event->hw;
7942 seq = __this_cpu_read(perf_throttled_seq);
7943 if (seq != hwc->interrupts_seq) {
7944 hwc->interrupts_seq = seq;
7945 hwc->interrupts = 1;
7948 if (unlikely(throttle
7949 && hwc->interrupts >= max_samples_per_tick)) {
7950 __this_cpu_inc(perf_throttled_count);
7951 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7952 hwc->interrupts = MAX_INTERRUPTS;
7953 perf_log_throttle(event, 0);
7958 if (event->attr.freq) {
7959 u64 now = perf_clock();
7960 s64 delta = now - hwc->freq_time_stamp;
7962 hwc->freq_time_stamp = now;
7964 if (delta > 0 && delta < 2*TICK_NSEC)
7965 perf_adjust_period(event, delta, hwc->last_period, true);
7971 int perf_event_account_interrupt(struct perf_event *event)
7973 return __perf_event_account_interrupt(event, 1);
7977 * Generic event overflow handling, sampling.
7980 static int __perf_event_overflow(struct perf_event *event,
7981 int throttle, struct perf_sample_data *data,
7982 struct pt_regs *regs)
7984 int events = atomic_read(&event->event_limit);
7988 * Non-sampling counters might still use the PMI to fold short
7989 * hardware counters, ignore those.
7991 if (unlikely(!is_sampling_event(event)))
7994 ret = __perf_event_account_interrupt(event, throttle);
7997 * XXX event_limit might not quite work as expected on inherited
8001 event->pending_kill = POLL_IN;
8002 if (events && atomic_dec_and_test(&event->event_limit)) {
8004 event->pending_kill = POLL_HUP;
8006 perf_event_disable_inatomic(event);
8009 READ_ONCE(event->overflow_handler)(event, data, regs);
8011 if (*perf_event_fasync(event) && event->pending_kill) {
8012 event->pending_wakeup = 1;
8013 irq_work_queue(&event->pending);
8019 int perf_event_overflow(struct perf_event *event,
8020 struct perf_sample_data *data,
8021 struct pt_regs *regs)
8023 return __perf_event_overflow(event, 1, data, regs);
8027 * Generic software event infrastructure
8030 struct swevent_htable {
8031 struct swevent_hlist *swevent_hlist;
8032 struct mutex hlist_mutex;
8035 /* Recursion avoidance in each contexts */
8036 int recursion[PERF_NR_CONTEXTS];
8039 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8042 * We directly increment event->count and keep a second value in
8043 * event->hw.period_left to count intervals. This period event
8044 * is kept in the range [-sample_period, 0] so that we can use the
8048 u64 perf_swevent_set_period(struct perf_event *event)
8050 struct hw_perf_event *hwc = &event->hw;
8051 u64 period = hwc->last_period;
8055 hwc->last_period = hwc->sample_period;
8058 old = val = local64_read(&hwc->period_left);
8062 nr = div64_u64(period + val, period);
8063 offset = nr * period;
8065 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8071 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8072 struct perf_sample_data *data,
8073 struct pt_regs *regs)
8075 struct hw_perf_event *hwc = &event->hw;
8079 overflow = perf_swevent_set_period(event);
8081 if (hwc->interrupts == MAX_INTERRUPTS)
8084 for (; overflow; overflow--) {
8085 if (__perf_event_overflow(event, throttle,
8088 * We inhibit the overflow from happening when
8089 * hwc->interrupts == MAX_INTERRUPTS.
8097 static void perf_swevent_event(struct perf_event *event, u64 nr,
8098 struct perf_sample_data *data,
8099 struct pt_regs *regs)
8101 struct hw_perf_event *hwc = &event->hw;
8103 local64_add(nr, &event->count);
8108 if (!is_sampling_event(event))
8111 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8113 return perf_swevent_overflow(event, 1, data, regs);
8115 data->period = event->hw.last_period;
8117 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8118 return perf_swevent_overflow(event, 1, data, regs);
8120 if (local64_add_negative(nr, &hwc->period_left))
8123 perf_swevent_overflow(event, 0, data, regs);
8126 static int perf_exclude_event(struct perf_event *event,
8127 struct pt_regs *regs)
8129 if (event->hw.state & PERF_HES_STOPPED)
8133 if (event->attr.exclude_user && user_mode(regs))
8136 if (event->attr.exclude_kernel && !user_mode(regs))
8143 static int perf_swevent_match(struct perf_event *event,
8144 enum perf_type_id type,
8146 struct perf_sample_data *data,
8147 struct pt_regs *regs)
8149 if (event->attr.type != type)
8152 if (event->attr.config != event_id)
8155 if (perf_exclude_event(event, regs))
8161 static inline u64 swevent_hash(u64 type, u32 event_id)
8163 u64 val = event_id | (type << 32);
8165 return hash_64(val, SWEVENT_HLIST_BITS);
8168 static inline struct hlist_head *
8169 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8171 u64 hash = swevent_hash(type, event_id);
8173 return &hlist->heads[hash];
8176 /* For the read side: events when they trigger */
8177 static inline struct hlist_head *
8178 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8180 struct swevent_hlist *hlist;
8182 hlist = rcu_dereference(swhash->swevent_hlist);
8186 return __find_swevent_head(hlist, type, event_id);
8189 /* For the event head insertion and removal in the hlist */
8190 static inline struct hlist_head *
8191 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8193 struct swevent_hlist *hlist;
8194 u32 event_id = event->attr.config;
8195 u64 type = event->attr.type;
8198 * Event scheduling is always serialized against hlist allocation
8199 * and release. Which makes the protected version suitable here.
8200 * The context lock guarantees that.
8202 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8203 lockdep_is_held(&event->ctx->lock));
8207 return __find_swevent_head(hlist, type, event_id);
8210 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8212 struct perf_sample_data *data,
8213 struct pt_regs *regs)
8215 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8216 struct perf_event *event;
8217 struct hlist_head *head;
8220 head = find_swevent_head_rcu(swhash, type, event_id);
8224 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8225 if (perf_swevent_match(event, type, event_id, data, regs))
8226 perf_swevent_event(event, nr, data, regs);
8232 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8234 int perf_swevent_get_recursion_context(void)
8236 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8238 return get_recursion_context(swhash->recursion);
8240 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8242 void perf_swevent_put_recursion_context(int rctx)
8244 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8246 put_recursion_context(swhash->recursion, rctx);
8249 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8251 struct perf_sample_data data;
8253 if (WARN_ON_ONCE(!regs))
8256 perf_sample_data_init(&data, addr, 0);
8257 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8260 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8264 preempt_disable_notrace();
8265 rctx = perf_swevent_get_recursion_context();
8266 if (unlikely(rctx < 0))
8269 ___perf_sw_event(event_id, nr, regs, addr);
8271 perf_swevent_put_recursion_context(rctx);
8273 preempt_enable_notrace();
8276 static void perf_swevent_read(struct perf_event *event)
8280 static int perf_swevent_add(struct perf_event *event, int flags)
8282 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8283 struct hw_perf_event *hwc = &event->hw;
8284 struct hlist_head *head;
8286 if (is_sampling_event(event)) {
8287 hwc->last_period = hwc->sample_period;
8288 perf_swevent_set_period(event);
8291 hwc->state = !(flags & PERF_EF_START);
8293 head = find_swevent_head(swhash, event);
8294 if (WARN_ON_ONCE(!head))
8297 hlist_add_head_rcu(&event->hlist_entry, head);
8298 perf_event_update_userpage(event);
8303 static void perf_swevent_del(struct perf_event *event, int flags)
8305 hlist_del_rcu(&event->hlist_entry);
8308 static void perf_swevent_start(struct perf_event *event, int flags)
8310 event->hw.state = 0;
8313 static void perf_swevent_stop(struct perf_event *event, int flags)
8315 event->hw.state = PERF_HES_STOPPED;
8318 /* Deref the hlist from the update side */
8319 static inline struct swevent_hlist *
8320 swevent_hlist_deref(struct swevent_htable *swhash)
8322 return rcu_dereference_protected(swhash->swevent_hlist,
8323 lockdep_is_held(&swhash->hlist_mutex));
8326 static void swevent_hlist_release(struct swevent_htable *swhash)
8328 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8333 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8334 kfree_rcu(hlist, rcu_head);
8337 static void swevent_hlist_put_cpu(int cpu)
8339 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8341 mutex_lock(&swhash->hlist_mutex);
8343 if (!--swhash->hlist_refcount)
8344 swevent_hlist_release(swhash);
8346 mutex_unlock(&swhash->hlist_mutex);
8349 static void swevent_hlist_put(void)
8353 for_each_possible_cpu(cpu)
8354 swevent_hlist_put_cpu(cpu);
8357 static int swevent_hlist_get_cpu(int cpu)
8359 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8362 mutex_lock(&swhash->hlist_mutex);
8363 if (!swevent_hlist_deref(swhash) &&
8364 cpumask_test_cpu(cpu, perf_online_mask)) {
8365 struct swevent_hlist *hlist;
8367 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8372 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8374 swhash->hlist_refcount++;
8376 mutex_unlock(&swhash->hlist_mutex);
8381 static int swevent_hlist_get(void)
8383 int err, cpu, failed_cpu;
8385 mutex_lock(&pmus_lock);
8386 for_each_possible_cpu(cpu) {
8387 err = swevent_hlist_get_cpu(cpu);
8393 mutex_unlock(&pmus_lock);
8396 for_each_possible_cpu(cpu) {
8397 if (cpu == failed_cpu)
8399 swevent_hlist_put_cpu(cpu);
8401 mutex_unlock(&pmus_lock);
8405 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8407 static void sw_perf_event_destroy(struct perf_event *event)
8409 u64 event_id = event->attr.config;
8411 WARN_ON(event->parent);
8413 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8414 swevent_hlist_put();
8417 static int perf_swevent_init(struct perf_event *event)
8419 u64 event_id = event->attr.config;
8421 if (event->attr.type != PERF_TYPE_SOFTWARE)
8425 * no branch sampling for software events
8427 if (has_branch_stack(event))
8431 case PERF_COUNT_SW_CPU_CLOCK:
8432 case PERF_COUNT_SW_TASK_CLOCK:
8439 if (event_id >= PERF_COUNT_SW_MAX)
8442 if (!event->parent) {
8445 err = swevent_hlist_get();
8449 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8450 event->destroy = sw_perf_event_destroy;
8456 static struct pmu perf_swevent = {
8457 .task_ctx_nr = perf_sw_context,
8459 .capabilities = PERF_PMU_CAP_NO_NMI,
8461 .event_init = perf_swevent_init,
8462 .add = perf_swevent_add,
8463 .del = perf_swevent_del,
8464 .start = perf_swevent_start,
8465 .stop = perf_swevent_stop,
8466 .read = perf_swevent_read,
8469 #ifdef CONFIG_EVENT_TRACING
8471 static int perf_tp_filter_match(struct perf_event *event,
8472 struct perf_sample_data *data)
8474 void *record = data->raw->frag.data;
8476 /* only top level events have filters set */
8478 event = event->parent;
8480 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8485 static int perf_tp_event_match(struct perf_event *event,
8486 struct perf_sample_data *data,
8487 struct pt_regs *regs)
8489 if (event->hw.state & PERF_HES_STOPPED)
8492 * All tracepoints are from kernel-space.
8494 if (event->attr.exclude_kernel)
8497 if (!perf_tp_filter_match(event, data))
8503 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8504 struct trace_event_call *call, u64 count,
8505 struct pt_regs *regs, struct hlist_head *head,
8506 struct task_struct *task)
8508 if (bpf_prog_array_valid(call)) {
8509 *(struct pt_regs **)raw_data = regs;
8510 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8511 perf_swevent_put_recursion_context(rctx);
8515 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8518 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8520 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8521 struct pt_regs *regs, struct hlist_head *head, int rctx,
8522 struct task_struct *task)
8524 struct perf_sample_data data;
8525 struct perf_event *event;
8527 struct perf_raw_record raw = {
8534 perf_sample_data_init(&data, 0, 0);
8537 perf_trace_buf_update(record, event_type);
8539 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8540 if (perf_tp_event_match(event, &data, regs))
8541 perf_swevent_event(event, count, &data, regs);
8545 * If we got specified a target task, also iterate its context and
8546 * deliver this event there too.
8548 if (task && task != current) {
8549 struct perf_event_context *ctx;
8550 struct trace_entry *entry = record;
8553 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8557 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8558 if (event->cpu != smp_processor_id())
8560 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8562 if (event->attr.config != entry->type)
8564 if (perf_tp_event_match(event, &data, regs))
8565 perf_swevent_event(event, count, &data, regs);
8571 perf_swevent_put_recursion_context(rctx);
8573 EXPORT_SYMBOL_GPL(perf_tp_event);
8575 static void tp_perf_event_destroy(struct perf_event *event)
8577 perf_trace_destroy(event);
8580 static int perf_tp_event_init(struct perf_event *event)
8584 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8588 * no branch sampling for tracepoint events
8590 if (has_branch_stack(event))
8593 err = perf_trace_init(event);
8597 event->destroy = tp_perf_event_destroy;
8602 static struct pmu perf_tracepoint = {
8603 .task_ctx_nr = perf_sw_context,
8605 .event_init = perf_tp_event_init,
8606 .add = perf_trace_add,
8607 .del = perf_trace_del,
8608 .start = perf_swevent_start,
8609 .stop = perf_swevent_stop,
8610 .read = perf_swevent_read,
8613 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8615 * Flags in config, used by dynamic PMU kprobe and uprobe
8616 * The flags should match following PMU_FORMAT_ATTR().
8618 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8619 * if not set, create kprobe/uprobe
8621 * The following values specify a reference counter (or semaphore in the
8622 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8623 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8625 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8626 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8628 enum perf_probe_config {
8629 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8630 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8631 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8634 PMU_FORMAT_ATTR(retprobe, "config:0");
8637 #ifdef CONFIG_KPROBE_EVENTS
8638 static struct attribute *kprobe_attrs[] = {
8639 &format_attr_retprobe.attr,
8643 static struct attribute_group kprobe_format_group = {
8645 .attrs = kprobe_attrs,
8648 static const struct attribute_group *kprobe_attr_groups[] = {
8649 &kprobe_format_group,
8653 static int perf_kprobe_event_init(struct perf_event *event);
8654 static struct pmu perf_kprobe = {
8655 .task_ctx_nr = perf_sw_context,
8656 .event_init = perf_kprobe_event_init,
8657 .add = perf_trace_add,
8658 .del = perf_trace_del,
8659 .start = perf_swevent_start,
8660 .stop = perf_swevent_stop,
8661 .read = perf_swevent_read,
8662 .attr_groups = kprobe_attr_groups,
8665 static int perf_kprobe_event_init(struct perf_event *event)
8670 if (event->attr.type != perf_kprobe.type)
8673 if (!capable(CAP_SYS_ADMIN))
8677 * no branch sampling for probe events
8679 if (has_branch_stack(event))
8682 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8683 err = perf_kprobe_init(event, is_retprobe);
8687 event->destroy = perf_kprobe_destroy;
8691 #endif /* CONFIG_KPROBE_EVENTS */
8693 #ifdef CONFIG_UPROBE_EVENTS
8694 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8696 static struct attribute *uprobe_attrs[] = {
8697 &format_attr_retprobe.attr,
8698 &format_attr_ref_ctr_offset.attr,
8702 static struct attribute_group uprobe_format_group = {
8704 .attrs = uprobe_attrs,
8707 static const struct attribute_group *uprobe_attr_groups[] = {
8708 &uprobe_format_group,
8712 static int perf_uprobe_event_init(struct perf_event *event);
8713 static struct pmu perf_uprobe = {
8714 .task_ctx_nr = perf_sw_context,
8715 .event_init = perf_uprobe_event_init,
8716 .add = perf_trace_add,
8717 .del = perf_trace_del,
8718 .start = perf_swevent_start,
8719 .stop = perf_swevent_stop,
8720 .read = perf_swevent_read,
8721 .attr_groups = uprobe_attr_groups,
8724 static int perf_uprobe_event_init(struct perf_event *event)
8727 unsigned long ref_ctr_offset;
8730 if (event->attr.type != perf_uprobe.type)
8733 if (!capable(CAP_SYS_ADMIN))
8737 * no branch sampling for probe events
8739 if (has_branch_stack(event))
8742 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8743 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8744 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8748 event->destroy = perf_uprobe_destroy;
8752 #endif /* CONFIG_UPROBE_EVENTS */
8754 static inline void perf_tp_register(void)
8756 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8757 #ifdef CONFIG_KPROBE_EVENTS
8758 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8760 #ifdef CONFIG_UPROBE_EVENTS
8761 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8765 static void perf_event_free_filter(struct perf_event *event)
8767 ftrace_profile_free_filter(event);
8770 #ifdef CONFIG_BPF_SYSCALL
8771 static void bpf_overflow_handler(struct perf_event *event,
8772 struct perf_sample_data *data,
8773 struct pt_regs *regs)
8775 struct bpf_perf_event_data_kern ctx = {
8781 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8783 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8786 ret = BPF_PROG_RUN(event->prog, &ctx);
8789 __this_cpu_dec(bpf_prog_active);
8794 event->orig_overflow_handler(event, data, regs);
8797 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8799 struct bpf_prog *prog;
8801 if (event->overflow_handler_context)
8802 /* hw breakpoint or kernel counter */
8808 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8810 return PTR_ERR(prog);
8813 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8814 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8818 static void perf_event_free_bpf_handler(struct perf_event *event)
8820 struct bpf_prog *prog = event->prog;
8825 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8830 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8834 static void perf_event_free_bpf_handler(struct perf_event *event)
8840 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8841 * with perf_event_open()
8843 static inline bool perf_event_is_tracing(struct perf_event *event)
8845 if (event->pmu == &perf_tracepoint)
8847 #ifdef CONFIG_KPROBE_EVENTS
8848 if (event->pmu == &perf_kprobe)
8851 #ifdef CONFIG_UPROBE_EVENTS
8852 if (event->pmu == &perf_uprobe)
8858 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8860 bool is_kprobe, is_tracepoint, is_syscall_tp;
8861 struct bpf_prog *prog;
8864 if (!perf_event_is_tracing(event))
8865 return perf_event_set_bpf_handler(event, prog_fd);
8867 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8868 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8869 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8870 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8871 /* bpf programs can only be attached to u/kprobe or tracepoint */
8874 prog = bpf_prog_get(prog_fd);
8876 return PTR_ERR(prog);
8878 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8879 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8880 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8881 /* valid fd, but invalid bpf program type */
8886 /* Kprobe override only works for kprobes, not uprobes. */
8887 if (prog->kprobe_override &&
8888 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8893 if (is_tracepoint || is_syscall_tp) {
8894 int off = trace_event_get_offsets(event->tp_event);
8896 if (prog->aux->max_ctx_offset > off) {
8902 ret = perf_event_attach_bpf_prog(event, prog);
8908 static void perf_event_free_bpf_prog(struct perf_event *event)
8910 if (!perf_event_is_tracing(event)) {
8911 perf_event_free_bpf_handler(event);
8914 perf_event_detach_bpf_prog(event);
8919 static inline void perf_tp_register(void)
8923 static void perf_event_free_filter(struct perf_event *event)
8927 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8932 static void perf_event_free_bpf_prog(struct perf_event *event)
8935 #endif /* CONFIG_EVENT_TRACING */
8937 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8938 void perf_bp_event(struct perf_event *bp, void *data)
8940 struct perf_sample_data sample;
8941 struct pt_regs *regs = data;
8943 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8945 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8946 perf_swevent_event(bp, 1, &sample, regs);
8951 * Allocate a new address filter
8953 static struct perf_addr_filter *
8954 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8956 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8957 struct perf_addr_filter *filter;
8959 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8963 INIT_LIST_HEAD(&filter->entry);
8964 list_add_tail(&filter->entry, filters);
8969 static void free_filters_list(struct list_head *filters)
8971 struct perf_addr_filter *filter, *iter;
8973 list_for_each_entry_safe(filter, iter, filters, entry) {
8974 path_put(&filter->path);
8975 list_del(&filter->entry);
8981 * Free existing address filters and optionally install new ones
8983 static void perf_addr_filters_splice(struct perf_event *event,
8984 struct list_head *head)
8986 unsigned long flags;
8989 if (!has_addr_filter(event))
8992 /* don't bother with children, they don't have their own filters */
8996 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8998 list_splice_init(&event->addr_filters.list, &list);
9000 list_splice(head, &event->addr_filters.list);
9002 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9004 free_filters_list(&list);
9008 * Scan through mm's vmas and see if one of them matches the
9009 * @filter; if so, adjust filter's address range.
9010 * Called with mm::mmap_sem down for reading.
9012 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9013 struct mm_struct *mm,
9014 struct perf_addr_filter_range *fr)
9016 struct vm_area_struct *vma;
9018 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9022 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9028 * Update event's address range filters based on the
9029 * task's existing mappings, if any.
9031 static void perf_event_addr_filters_apply(struct perf_event *event)
9033 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9034 struct task_struct *task = READ_ONCE(event->ctx->task);
9035 struct perf_addr_filter *filter;
9036 struct mm_struct *mm = NULL;
9037 unsigned int count = 0;
9038 unsigned long flags;
9041 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9042 * will stop on the parent's child_mutex that our caller is also holding
9044 if (task == TASK_TOMBSTONE)
9047 if (!ifh->nr_file_filters)
9050 mm = get_task_mm(event->ctx->task);
9054 down_read(&mm->mmap_sem);
9056 raw_spin_lock_irqsave(&ifh->lock, flags);
9057 list_for_each_entry(filter, &ifh->list, entry) {
9058 event->addr_filter_ranges[count].start = 0;
9059 event->addr_filter_ranges[count].size = 0;
9062 * Adjust base offset if the filter is associated to a binary
9063 * that needs to be mapped:
9065 if (filter->path.dentry)
9066 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9071 event->addr_filters_gen++;
9072 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9074 up_read(&mm->mmap_sem);
9079 perf_event_stop(event, 1);
9083 * Address range filtering: limiting the data to certain
9084 * instruction address ranges. Filters are ioctl()ed to us from
9085 * userspace as ascii strings.
9087 * Filter string format:
9090 * where ACTION is one of the
9091 * * "filter": limit the trace to this region
9092 * * "start": start tracing from this address
9093 * * "stop": stop tracing at this address/region;
9095 * * for kernel addresses: <start address>[/<size>]
9096 * * for object files: <start address>[/<size>]@</path/to/object/file>
9098 * if <size> is not specified or is zero, the range is treated as a single
9099 * address; not valid for ACTION=="filter".
9113 IF_STATE_ACTION = 0,
9118 static const match_table_t if_tokens = {
9119 { IF_ACT_FILTER, "filter" },
9120 { IF_ACT_START, "start" },
9121 { IF_ACT_STOP, "stop" },
9122 { IF_SRC_FILE, "%u/%u@%s" },
9123 { IF_SRC_KERNEL, "%u/%u" },
9124 { IF_SRC_FILEADDR, "%u@%s" },
9125 { IF_SRC_KERNELADDR, "%u" },
9126 { IF_ACT_NONE, NULL },
9130 * Address filter string parser
9133 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9134 struct list_head *filters)
9136 struct perf_addr_filter *filter = NULL;
9137 char *start, *orig, *filename = NULL;
9138 substring_t args[MAX_OPT_ARGS];
9139 int state = IF_STATE_ACTION, token;
9140 unsigned int kernel = 0;
9143 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9147 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9148 static const enum perf_addr_filter_action_t actions[] = {
9149 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9150 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9151 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9158 /* filter definition begins */
9159 if (state == IF_STATE_ACTION) {
9160 filter = perf_addr_filter_new(event, filters);
9165 token = match_token(start, if_tokens, args);
9170 if (state != IF_STATE_ACTION)
9173 filter->action = actions[token];
9174 state = IF_STATE_SOURCE;
9177 case IF_SRC_KERNELADDR:
9182 case IF_SRC_FILEADDR:
9184 if (state != IF_STATE_SOURCE)
9188 ret = kstrtoul(args[0].from, 0, &filter->offset);
9192 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9194 ret = kstrtoul(args[1].from, 0, &filter->size);
9199 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9200 int fpos = token == IF_SRC_FILE ? 2 : 1;
9202 filename = match_strdup(&args[fpos]);
9209 state = IF_STATE_END;
9217 * Filter definition is fully parsed, validate and install it.
9218 * Make sure that it doesn't contradict itself or the event's
9221 if (state == IF_STATE_END) {
9223 if (kernel && event->attr.exclude_kernel)
9227 * ACTION "filter" must have a non-zero length region
9230 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9239 * For now, we only support file-based filters
9240 * in per-task events; doing so for CPU-wide
9241 * events requires additional context switching
9242 * trickery, since same object code will be
9243 * mapped at different virtual addresses in
9244 * different processes.
9247 if (!event->ctx->task)
9248 goto fail_free_name;
9250 /* look up the path and grab its inode */
9251 ret = kern_path(filename, LOOKUP_FOLLOW,
9254 goto fail_free_name;
9260 if (!filter->path.dentry ||
9261 !S_ISREG(d_inode(filter->path.dentry)
9265 event->addr_filters.nr_file_filters++;
9268 /* ready to consume more filters */
9269 state = IF_STATE_ACTION;
9274 if (state != IF_STATE_ACTION)
9284 free_filters_list(filters);
9291 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9297 * Since this is called in perf_ioctl() path, we're already holding
9300 lockdep_assert_held(&event->ctx->mutex);
9302 if (WARN_ON_ONCE(event->parent))
9305 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9307 goto fail_clear_files;
9309 ret = event->pmu->addr_filters_validate(&filters);
9311 goto fail_free_filters;
9313 /* remove existing filters, if any */
9314 perf_addr_filters_splice(event, &filters);
9316 /* install new filters */
9317 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9322 free_filters_list(&filters);
9325 event->addr_filters.nr_file_filters = 0;
9330 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9335 filter_str = strndup_user(arg, PAGE_SIZE);
9336 if (IS_ERR(filter_str))
9337 return PTR_ERR(filter_str);
9339 #ifdef CONFIG_EVENT_TRACING
9340 if (perf_event_is_tracing(event)) {
9341 struct perf_event_context *ctx = event->ctx;
9344 * Beware, here be dragons!!
9346 * the tracepoint muck will deadlock against ctx->mutex, but
9347 * the tracepoint stuff does not actually need it. So
9348 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9349 * already have a reference on ctx.
9351 * This can result in event getting moved to a different ctx,
9352 * but that does not affect the tracepoint state.
9354 mutex_unlock(&ctx->mutex);
9355 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9356 mutex_lock(&ctx->mutex);
9359 if (has_addr_filter(event))
9360 ret = perf_event_set_addr_filter(event, filter_str);
9367 * hrtimer based swevent callback
9370 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9372 enum hrtimer_restart ret = HRTIMER_RESTART;
9373 struct perf_sample_data data;
9374 struct pt_regs *regs;
9375 struct perf_event *event;
9378 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9380 if (event->state != PERF_EVENT_STATE_ACTIVE)
9381 return HRTIMER_NORESTART;
9383 event->pmu->read(event);
9385 perf_sample_data_init(&data, 0, event->hw.last_period);
9386 regs = get_irq_regs();
9388 if (regs && !perf_exclude_event(event, regs)) {
9389 if (!(event->attr.exclude_idle && is_idle_task(current)))
9390 if (__perf_event_overflow(event, 1, &data, regs))
9391 ret = HRTIMER_NORESTART;
9394 period = max_t(u64, 10000, event->hw.sample_period);
9395 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9400 static void perf_swevent_start_hrtimer(struct perf_event *event)
9402 struct hw_perf_event *hwc = &event->hw;
9405 if (!is_sampling_event(event))
9408 period = local64_read(&hwc->period_left);
9413 local64_set(&hwc->period_left, 0);
9415 period = max_t(u64, 10000, hwc->sample_period);
9417 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9418 HRTIMER_MODE_REL_PINNED);
9421 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9423 struct hw_perf_event *hwc = &event->hw;
9425 if (is_sampling_event(event)) {
9426 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9427 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9429 hrtimer_cancel(&hwc->hrtimer);
9433 static void perf_swevent_init_hrtimer(struct perf_event *event)
9435 struct hw_perf_event *hwc = &event->hw;
9437 if (!is_sampling_event(event))
9440 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9441 hwc->hrtimer.function = perf_swevent_hrtimer;
9444 * Since hrtimers have a fixed rate, we can do a static freq->period
9445 * mapping and avoid the whole period adjust feedback stuff.
9447 if (event->attr.freq) {
9448 long freq = event->attr.sample_freq;
9450 event->attr.sample_period = NSEC_PER_SEC / freq;
9451 hwc->sample_period = event->attr.sample_period;
9452 local64_set(&hwc->period_left, hwc->sample_period);
9453 hwc->last_period = hwc->sample_period;
9454 event->attr.freq = 0;
9459 * Software event: cpu wall time clock
9462 static void cpu_clock_event_update(struct perf_event *event)
9467 now = local_clock();
9468 prev = local64_xchg(&event->hw.prev_count, now);
9469 local64_add(now - prev, &event->count);
9472 static void cpu_clock_event_start(struct perf_event *event, int flags)
9474 local64_set(&event->hw.prev_count, local_clock());
9475 perf_swevent_start_hrtimer(event);
9478 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9480 perf_swevent_cancel_hrtimer(event);
9481 cpu_clock_event_update(event);
9484 static int cpu_clock_event_add(struct perf_event *event, int flags)
9486 if (flags & PERF_EF_START)
9487 cpu_clock_event_start(event, flags);
9488 perf_event_update_userpage(event);
9493 static void cpu_clock_event_del(struct perf_event *event, int flags)
9495 cpu_clock_event_stop(event, flags);
9498 static void cpu_clock_event_read(struct perf_event *event)
9500 cpu_clock_event_update(event);
9503 static int cpu_clock_event_init(struct perf_event *event)
9505 if (event->attr.type != PERF_TYPE_SOFTWARE)
9508 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9512 * no branch sampling for software events
9514 if (has_branch_stack(event))
9517 perf_swevent_init_hrtimer(event);
9522 static struct pmu perf_cpu_clock = {
9523 .task_ctx_nr = perf_sw_context,
9525 .capabilities = PERF_PMU_CAP_NO_NMI,
9527 .event_init = cpu_clock_event_init,
9528 .add = cpu_clock_event_add,
9529 .del = cpu_clock_event_del,
9530 .start = cpu_clock_event_start,
9531 .stop = cpu_clock_event_stop,
9532 .read = cpu_clock_event_read,
9536 * Software event: task time clock
9539 static void task_clock_event_update(struct perf_event *event, u64 now)
9544 prev = local64_xchg(&event->hw.prev_count, now);
9546 local64_add(delta, &event->count);
9549 static void task_clock_event_start(struct perf_event *event, int flags)
9551 local64_set(&event->hw.prev_count, event->ctx->time);
9552 perf_swevent_start_hrtimer(event);
9555 static void task_clock_event_stop(struct perf_event *event, int flags)
9557 perf_swevent_cancel_hrtimer(event);
9558 task_clock_event_update(event, event->ctx->time);
9561 static int task_clock_event_add(struct perf_event *event, int flags)
9563 if (flags & PERF_EF_START)
9564 task_clock_event_start(event, flags);
9565 perf_event_update_userpage(event);
9570 static void task_clock_event_del(struct perf_event *event, int flags)
9572 task_clock_event_stop(event, PERF_EF_UPDATE);
9575 static void task_clock_event_read(struct perf_event *event)
9577 u64 now = perf_clock();
9578 u64 delta = now - event->ctx->timestamp;
9579 u64 time = event->ctx->time + delta;
9581 task_clock_event_update(event, time);
9584 static int task_clock_event_init(struct perf_event *event)
9586 if (event->attr.type != PERF_TYPE_SOFTWARE)
9589 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9593 * no branch sampling for software events
9595 if (has_branch_stack(event))
9598 perf_swevent_init_hrtimer(event);
9603 static struct pmu perf_task_clock = {
9604 .task_ctx_nr = perf_sw_context,
9606 .capabilities = PERF_PMU_CAP_NO_NMI,
9608 .event_init = task_clock_event_init,
9609 .add = task_clock_event_add,
9610 .del = task_clock_event_del,
9611 .start = task_clock_event_start,
9612 .stop = task_clock_event_stop,
9613 .read = task_clock_event_read,
9616 static void perf_pmu_nop_void(struct pmu *pmu)
9620 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9624 static int perf_pmu_nop_int(struct pmu *pmu)
9629 static int perf_event_nop_int(struct perf_event *event, u64 value)
9634 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9636 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9638 __this_cpu_write(nop_txn_flags, flags);
9640 if (flags & ~PERF_PMU_TXN_ADD)
9643 perf_pmu_disable(pmu);
9646 static int perf_pmu_commit_txn(struct pmu *pmu)
9648 unsigned int flags = __this_cpu_read(nop_txn_flags);
9650 __this_cpu_write(nop_txn_flags, 0);
9652 if (flags & ~PERF_PMU_TXN_ADD)
9655 perf_pmu_enable(pmu);
9659 static void perf_pmu_cancel_txn(struct pmu *pmu)
9661 unsigned int flags = __this_cpu_read(nop_txn_flags);
9663 __this_cpu_write(nop_txn_flags, 0);
9665 if (flags & ~PERF_PMU_TXN_ADD)
9668 perf_pmu_enable(pmu);
9671 static int perf_event_idx_default(struct perf_event *event)
9677 * Ensures all contexts with the same task_ctx_nr have the same
9678 * pmu_cpu_context too.
9680 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9687 list_for_each_entry(pmu, &pmus, entry) {
9688 if (pmu->task_ctx_nr == ctxn)
9689 return pmu->pmu_cpu_context;
9695 static void free_pmu_context(struct pmu *pmu)
9698 * Static contexts such as perf_sw_context have a global lifetime
9699 * and may be shared between different PMUs. Avoid freeing them
9700 * when a single PMU is going away.
9702 if (pmu->task_ctx_nr > perf_invalid_context)
9705 free_percpu(pmu->pmu_cpu_context);
9709 * Let userspace know that this PMU supports address range filtering:
9711 static ssize_t nr_addr_filters_show(struct device *dev,
9712 struct device_attribute *attr,
9715 struct pmu *pmu = dev_get_drvdata(dev);
9717 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9719 DEVICE_ATTR_RO(nr_addr_filters);
9721 static struct idr pmu_idr;
9724 type_show(struct device *dev, struct device_attribute *attr, char *page)
9726 struct pmu *pmu = dev_get_drvdata(dev);
9728 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9730 static DEVICE_ATTR_RO(type);
9733 perf_event_mux_interval_ms_show(struct device *dev,
9734 struct device_attribute *attr,
9737 struct pmu *pmu = dev_get_drvdata(dev);
9739 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9742 static DEFINE_MUTEX(mux_interval_mutex);
9745 perf_event_mux_interval_ms_store(struct device *dev,
9746 struct device_attribute *attr,
9747 const char *buf, size_t count)
9749 struct pmu *pmu = dev_get_drvdata(dev);
9750 int timer, cpu, ret;
9752 ret = kstrtoint(buf, 0, &timer);
9759 /* same value, noting to do */
9760 if (timer == pmu->hrtimer_interval_ms)
9763 mutex_lock(&mux_interval_mutex);
9764 pmu->hrtimer_interval_ms = timer;
9766 /* update all cpuctx for this PMU */
9768 for_each_online_cpu(cpu) {
9769 struct perf_cpu_context *cpuctx;
9770 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9771 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9773 cpu_function_call(cpu,
9774 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9777 mutex_unlock(&mux_interval_mutex);
9781 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9783 static struct attribute *pmu_dev_attrs[] = {
9784 &dev_attr_type.attr,
9785 &dev_attr_perf_event_mux_interval_ms.attr,
9788 ATTRIBUTE_GROUPS(pmu_dev);
9790 static int pmu_bus_running;
9791 static struct bus_type pmu_bus = {
9792 .name = "event_source",
9793 .dev_groups = pmu_dev_groups,
9796 static void pmu_dev_release(struct device *dev)
9801 static int pmu_dev_alloc(struct pmu *pmu)
9805 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9809 pmu->dev->groups = pmu->attr_groups;
9810 device_initialize(pmu->dev);
9811 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9815 dev_set_drvdata(pmu->dev, pmu);
9816 pmu->dev->bus = &pmu_bus;
9817 pmu->dev->release = pmu_dev_release;
9818 ret = device_add(pmu->dev);
9822 /* For PMUs with address filters, throw in an extra attribute: */
9823 if (pmu->nr_addr_filters)
9824 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9833 device_del(pmu->dev);
9836 put_device(pmu->dev);
9840 static struct lock_class_key cpuctx_mutex;
9841 static struct lock_class_key cpuctx_lock;
9843 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9847 mutex_lock(&pmus_lock);
9849 pmu->pmu_disable_count = alloc_percpu(int);
9850 if (!pmu->pmu_disable_count)
9859 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9867 if (pmu_bus_running) {
9868 ret = pmu_dev_alloc(pmu);
9874 if (pmu->task_ctx_nr == perf_hw_context) {
9875 static int hw_context_taken = 0;
9878 * Other than systems with heterogeneous CPUs, it never makes
9879 * sense for two PMUs to share perf_hw_context. PMUs which are
9880 * uncore must use perf_invalid_context.
9882 if (WARN_ON_ONCE(hw_context_taken &&
9883 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9884 pmu->task_ctx_nr = perf_invalid_context;
9886 hw_context_taken = 1;
9889 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9890 if (pmu->pmu_cpu_context)
9891 goto got_cpu_context;
9894 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9895 if (!pmu->pmu_cpu_context)
9898 for_each_possible_cpu(cpu) {
9899 struct perf_cpu_context *cpuctx;
9901 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9902 __perf_event_init_context(&cpuctx->ctx);
9903 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9904 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9905 cpuctx->ctx.pmu = pmu;
9906 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9908 __perf_mux_hrtimer_init(cpuctx, cpu);
9912 if (!pmu->start_txn) {
9913 if (pmu->pmu_enable) {
9915 * If we have pmu_enable/pmu_disable calls, install
9916 * transaction stubs that use that to try and batch
9917 * hardware accesses.
9919 pmu->start_txn = perf_pmu_start_txn;
9920 pmu->commit_txn = perf_pmu_commit_txn;
9921 pmu->cancel_txn = perf_pmu_cancel_txn;
9923 pmu->start_txn = perf_pmu_nop_txn;
9924 pmu->commit_txn = perf_pmu_nop_int;
9925 pmu->cancel_txn = perf_pmu_nop_void;
9929 if (!pmu->pmu_enable) {
9930 pmu->pmu_enable = perf_pmu_nop_void;
9931 pmu->pmu_disable = perf_pmu_nop_void;
9934 if (!pmu->check_period)
9935 pmu->check_period = perf_event_nop_int;
9937 if (!pmu->event_idx)
9938 pmu->event_idx = perf_event_idx_default;
9940 list_add_rcu(&pmu->entry, &pmus);
9941 atomic_set(&pmu->exclusive_cnt, 0);
9944 mutex_unlock(&pmus_lock);
9949 device_del(pmu->dev);
9950 put_device(pmu->dev);
9953 if (pmu->type >= PERF_TYPE_MAX)
9954 idr_remove(&pmu_idr, pmu->type);
9957 free_percpu(pmu->pmu_disable_count);
9960 EXPORT_SYMBOL_GPL(perf_pmu_register);
9962 void perf_pmu_unregister(struct pmu *pmu)
9964 mutex_lock(&pmus_lock);
9965 list_del_rcu(&pmu->entry);
9968 * We dereference the pmu list under both SRCU and regular RCU, so
9969 * synchronize against both of those.
9971 synchronize_srcu(&pmus_srcu);
9974 free_percpu(pmu->pmu_disable_count);
9975 if (pmu->type >= PERF_TYPE_MAX)
9976 idr_remove(&pmu_idr, pmu->type);
9977 if (pmu_bus_running) {
9978 if (pmu->nr_addr_filters)
9979 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9980 device_del(pmu->dev);
9981 put_device(pmu->dev);
9983 free_pmu_context(pmu);
9984 mutex_unlock(&pmus_lock);
9986 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9988 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9990 struct perf_event_context *ctx = NULL;
9993 if (!try_module_get(pmu->module))
9997 * A number of pmu->event_init() methods iterate the sibling_list to,
9998 * for example, validate if the group fits on the PMU. Therefore,
9999 * if this is a sibling event, acquire the ctx->mutex to protect
10000 * the sibling_list.
10002 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10004 * This ctx->mutex can nest when we're called through
10005 * inheritance. See the perf_event_ctx_lock_nested() comment.
10007 ctx = perf_event_ctx_lock_nested(event->group_leader,
10008 SINGLE_DEPTH_NESTING);
10013 ret = pmu->event_init(event);
10016 perf_event_ctx_unlock(event->group_leader, ctx);
10019 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10020 event_has_any_exclude_flag(event)) {
10021 if (event->destroy)
10022 event->destroy(event);
10028 module_put(pmu->module);
10033 static struct pmu *perf_init_event(struct perf_event *event)
10039 idx = srcu_read_lock(&pmus_srcu);
10041 /* Try parent's PMU first: */
10042 if (event->parent && event->parent->pmu) {
10043 pmu = event->parent->pmu;
10044 ret = perf_try_init_event(pmu, event);
10050 pmu = idr_find(&pmu_idr, event->attr.type);
10053 ret = perf_try_init_event(pmu, event);
10055 pmu = ERR_PTR(ret);
10059 list_for_each_entry_rcu(pmu, &pmus, entry) {
10060 ret = perf_try_init_event(pmu, event);
10064 if (ret != -ENOENT) {
10065 pmu = ERR_PTR(ret);
10069 pmu = ERR_PTR(-ENOENT);
10071 srcu_read_unlock(&pmus_srcu, idx);
10076 static void attach_sb_event(struct perf_event *event)
10078 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10080 raw_spin_lock(&pel->lock);
10081 list_add_rcu(&event->sb_list, &pel->list);
10082 raw_spin_unlock(&pel->lock);
10086 * We keep a list of all !task (and therefore per-cpu) events
10087 * that need to receive side-band records.
10089 * This avoids having to scan all the various PMU per-cpu contexts
10090 * looking for them.
10092 static void account_pmu_sb_event(struct perf_event *event)
10094 if (is_sb_event(event))
10095 attach_sb_event(event);
10098 static void account_event_cpu(struct perf_event *event, int cpu)
10103 if (is_cgroup_event(event))
10104 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10107 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10108 static void account_freq_event_nohz(void)
10110 #ifdef CONFIG_NO_HZ_FULL
10111 /* Lock so we don't race with concurrent unaccount */
10112 spin_lock(&nr_freq_lock);
10113 if (atomic_inc_return(&nr_freq_events) == 1)
10114 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10115 spin_unlock(&nr_freq_lock);
10119 static void account_freq_event(void)
10121 if (tick_nohz_full_enabled())
10122 account_freq_event_nohz();
10124 atomic_inc(&nr_freq_events);
10128 static void account_event(struct perf_event *event)
10135 if (event->attach_state & PERF_ATTACH_TASK)
10137 if (event->attr.mmap || event->attr.mmap_data)
10138 atomic_inc(&nr_mmap_events);
10139 if (event->attr.comm)
10140 atomic_inc(&nr_comm_events);
10141 if (event->attr.namespaces)
10142 atomic_inc(&nr_namespaces_events);
10143 if (event->attr.task)
10144 atomic_inc(&nr_task_events);
10145 if (event->attr.freq)
10146 account_freq_event();
10147 if (event->attr.context_switch) {
10148 atomic_inc(&nr_switch_events);
10151 if (has_branch_stack(event))
10153 if (is_cgroup_event(event))
10155 if (event->attr.ksymbol)
10156 atomic_inc(&nr_ksymbol_events);
10157 if (event->attr.bpf_event)
10158 atomic_inc(&nr_bpf_events);
10162 * We need the mutex here because static_branch_enable()
10163 * must complete *before* the perf_sched_count increment
10166 if (atomic_inc_not_zero(&perf_sched_count))
10169 mutex_lock(&perf_sched_mutex);
10170 if (!atomic_read(&perf_sched_count)) {
10171 static_branch_enable(&perf_sched_events);
10173 * Guarantee that all CPUs observe they key change and
10174 * call the perf scheduling hooks before proceeding to
10175 * install events that need them.
10180 * Now that we have waited for the sync_sched(), allow further
10181 * increments to by-pass the mutex.
10183 atomic_inc(&perf_sched_count);
10184 mutex_unlock(&perf_sched_mutex);
10188 account_event_cpu(event, event->cpu);
10190 account_pmu_sb_event(event);
10194 * Allocate and initialize an event structure
10196 static struct perf_event *
10197 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10198 struct task_struct *task,
10199 struct perf_event *group_leader,
10200 struct perf_event *parent_event,
10201 perf_overflow_handler_t overflow_handler,
10202 void *context, int cgroup_fd)
10205 struct perf_event *event;
10206 struct hw_perf_event *hwc;
10207 long err = -EINVAL;
10209 if ((unsigned)cpu >= nr_cpu_ids) {
10210 if (!task || cpu != -1)
10211 return ERR_PTR(-EINVAL);
10214 event = kzalloc(sizeof(*event), GFP_KERNEL);
10216 return ERR_PTR(-ENOMEM);
10219 * Single events are their own group leaders, with an
10220 * empty sibling list:
10223 group_leader = event;
10225 mutex_init(&event->child_mutex);
10226 INIT_LIST_HEAD(&event->child_list);
10228 INIT_LIST_HEAD(&event->event_entry);
10229 INIT_LIST_HEAD(&event->sibling_list);
10230 INIT_LIST_HEAD(&event->active_list);
10231 init_event_group(event);
10232 INIT_LIST_HEAD(&event->rb_entry);
10233 INIT_LIST_HEAD(&event->active_entry);
10234 INIT_LIST_HEAD(&event->addr_filters.list);
10235 INIT_HLIST_NODE(&event->hlist_entry);
10238 init_waitqueue_head(&event->waitq);
10239 init_irq_work(&event->pending, perf_pending_event);
10241 mutex_init(&event->mmap_mutex);
10242 raw_spin_lock_init(&event->addr_filters.lock);
10244 atomic_long_set(&event->refcount, 1);
10246 event->attr = *attr;
10247 event->group_leader = group_leader;
10251 event->parent = parent_event;
10253 event->ns = get_pid_ns(task_active_pid_ns(current));
10254 event->id = atomic64_inc_return(&perf_event_id);
10256 event->state = PERF_EVENT_STATE_INACTIVE;
10259 event->attach_state = PERF_ATTACH_TASK;
10261 * XXX pmu::event_init needs to know what task to account to
10262 * and we cannot use the ctx information because we need the
10263 * pmu before we get a ctx.
10265 get_task_struct(task);
10266 event->hw.target = task;
10269 event->clock = &local_clock;
10271 event->clock = parent_event->clock;
10273 if (!overflow_handler && parent_event) {
10274 overflow_handler = parent_event->overflow_handler;
10275 context = parent_event->overflow_handler_context;
10276 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10277 if (overflow_handler == bpf_overflow_handler) {
10278 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10280 if (IS_ERR(prog)) {
10281 err = PTR_ERR(prog);
10284 event->prog = prog;
10285 event->orig_overflow_handler =
10286 parent_event->orig_overflow_handler;
10291 if (overflow_handler) {
10292 event->overflow_handler = overflow_handler;
10293 event->overflow_handler_context = context;
10294 } else if (is_write_backward(event)){
10295 event->overflow_handler = perf_event_output_backward;
10296 event->overflow_handler_context = NULL;
10298 event->overflow_handler = perf_event_output_forward;
10299 event->overflow_handler_context = NULL;
10302 perf_event__state_init(event);
10307 hwc->sample_period = attr->sample_period;
10308 if (attr->freq && attr->sample_freq)
10309 hwc->sample_period = 1;
10310 hwc->last_period = hwc->sample_period;
10312 local64_set(&hwc->period_left, hwc->sample_period);
10315 * We currently do not support PERF_SAMPLE_READ on inherited events.
10316 * See perf_output_read().
10318 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10321 if (!has_branch_stack(event))
10322 event->attr.branch_sample_type = 0;
10324 if (cgroup_fd != -1) {
10325 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10330 pmu = perf_init_event(event);
10332 err = PTR_ERR(pmu);
10336 err = exclusive_event_init(event);
10340 if (has_addr_filter(event)) {
10341 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10342 sizeof(struct perf_addr_filter_range),
10344 if (!event->addr_filter_ranges) {
10350 * Clone the parent's vma offsets: they are valid until exec()
10351 * even if the mm is not shared with the parent.
10353 if (event->parent) {
10354 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10356 raw_spin_lock_irq(&ifh->lock);
10357 memcpy(event->addr_filter_ranges,
10358 event->parent->addr_filter_ranges,
10359 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10360 raw_spin_unlock_irq(&ifh->lock);
10363 /* force hw sync on the address filters */
10364 event->addr_filters_gen = 1;
10367 if (!event->parent) {
10368 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10369 err = get_callchain_buffers(attr->sample_max_stack);
10371 goto err_addr_filters;
10375 /* symmetric to unaccount_event() in _free_event() */
10376 account_event(event);
10381 kfree(event->addr_filter_ranges);
10384 exclusive_event_destroy(event);
10387 if (event->destroy)
10388 event->destroy(event);
10389 module_put(pmu->module);
10391 if (is_cgroup_event(event))
10392 perf_detach_cgroup(event);
10394 put_pid_ns(event->ns);
10395 if (event->hw.target)
10396 put_task_struct(event->hw.target);
10399 return ERR_PTR(err);
10402 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10403 struct perf_event_attr *attr)
10408 if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
10412 * zero the full structure, so that a short copy will be nice.
10414 memset(attr, 0, sizeof(*attr));
10416 ret = get_user(size, &uattr->size);
10420 if (size > PAGE_SIZE) /* silly large */
10423 if (!size) /* abi compat */
10424 size = PERF_ATTR_SIZE_VER0;
10426 if (size < PERF_ATTR_SIZE_VER0)
10430 * If we're handed a bigger struct than we know of,
10431 * ensure all the unknown bits are 0 - i.e. new
10432 * user-space does not rely on any kernel feature
10433 * extensions we dont know about yet.
10435 if (size > sizeof(*attr)) {
10436 unsigned char __user *addr;
10437 unsigned char __user *end;
10440 addr = (void __user *)uattr + sizeof(*attr);
10441 end = (void __user *)uattr + size;
10443 for (; addr < end; addr++) {
10444 ret = get_user(val, addr);
10450 size = sizeof(*attr);
10453 ret = copy_from_user(attr, uattr, size);
10459 if (attr->__reserved_1)
10462 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10465 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10468 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10469 u64 mask = attr->branch_sample_type;
10471 /* only using defined bits */
10472 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10475 /* at least one branch bit must be set */
10476 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10479 /* propagate priv level, when not set for branch */
10480 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10482 /* exclude_kernel checked on syscall entry */
10483 if (!attr->exclude_kernel)
10484 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10486 if (!attr->exclude_user)
10487 mask |= PERF_SAMPLE_BRANCH_USER;
10489 if (!attr->exclude_hv)
10490 mask |= PERF_SAMPLE_BRANCH_HV;
10492 * adjust user setting (for HW filter setup)
10494 attr->branch_sample_type = mask;
10496 /* privileged levels capture (kernel, hv): check permissions */
10497 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10498 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10502 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10503 ret = perf_reg_validate(attr->sample_regs_user);
10508 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10509 if (!arch_perf_have_user_stack_dump())
10513 * We have __u32 type for the size, but so far
10514 * we can only use __u16 as maximum due to the
10515 * __u16 sample size limit.
10517 if (attr->sample_stack_user >= USHRT_MAX)
10519 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10523 if (!attr->sample_max_stack)
10524 attr->sample_max_stack = sysctl_perf_event_max_stack;
10526 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10527 ret = perf_reg_validate(attr->sample_regs_intr);
10532 put_user(sizeof(*attr), &uattr->size);
10538 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10540 struct ring_buffer *rb = NULL;
10546 /* don't allow circular references */
10547 if (event == output_event)
10551 * Don't allow cross-cpu buffers
10553 if (output_event->cpu != event->cpu)
10557 * If its not a per-cpu rb, it must be the same task.
10559 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10563 * Mixing clocks in the same buffer is trouble you don't need.
10565 if (output_event->clock != event->clock)
10569 * Either writing ring buffer from beginning or from end.
10570 * Mixing is not allowed.
10572 if (is_write_backward(output_event) != is_write_backward(event))
10576 * If both events generate aux data, they must be on the same PMU
10578 if (has_aux(event) && has_aux(output_event) &&
10579 event->pmu != output_event->pmu)
10583 mutex_lock(&event->mmap_mutex);
10584 /* Can't redirect output if we've got an active mmap() */
10585 if (atomic_read(&event->mmap_count))
10588 if (output_event) {
10589 /* get the rb we want to redirect to */
10590 rb = ring_buffer_get(output_event);
10595 ring_buffer_attach(event, rb);
10599 mutex_unlock(&event->mmap_mutex);
10605 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10611 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10614 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10616 bool nmi_safe = false;
10619 case CLOCK_MONOTONIC:
10620 event->clock = &ktime_get_mono_fast_ns;
10624 case CLOCK_MONOTONIC_RAW:
10625 event->clock = &ktime_get_raw_fast_ns;
10629 case CLOCK_REALTIME:
10630 event->clock = &ktime_get_real_ns;
10633 case CLOCK_BOOTTIME:
10634 event->clock = &ktime_get_boot_ns;
10638 event->clock = &ktime_get_tai_ns;
10645 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10652 * Variation on perf_event_ctx_lock_nested(), except we take two context
10655 static struct perf_event_context *
10656 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10657 struct perf_event_context *ctx)
10659 struct perf_event_context *gctx;
10663 gctx = READ_ONCE(group_leader->ctx);
10664 if (!refcount_inc_not_zero(&gctx->refcount)) {
10670 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10672 if (group_leader->ctx != gctx) {
10673 mutex_unlock(&ctx->mutex);
10674 mutex_unlock(&gctx->mutex);
10683 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10685 * @attr_uptr: event_id type attributes for monitoring/sampling
10688 * @group_fd: group leader event fd
10690 SYSCALL_DEFINE5(perf_event_open,
10691 struct perf_event_attr __user *, attr_uptr,
10692 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10694 struct perf_event *group_leader = NULL, *output_event = NULL;
10695 struct perf_event *event, *sibling;
10696 struct perf_event_attr attr;
10697 struct perf_event_context *ctx, *uninitialized_var(gctx);
10698 struct file *event_file = NULL;
10699 struct fd group = {NULL, 0};
10700 struct task_struct *task = NULL;
10703 int move_group = 0;
10705 int f_flags = O_RDWR;
10706 int cgroup_fd = -1;
10708 /* for future expandability... */
10709 if (flags & ~PERF_FLAG_ALL)
10712 err = perf_copy_attr(attr_uptr, &attr);
10716 if (!attr.exclude_kernel) {
10717 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10721 if (attr.namespaces) {
10722 if (!capable(CAP_SYS_ADMIN))
10727 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10730 if (attr.sample_period & (1ULL << 63))
10734 /* Only privileged users can get physical addresses */
10735 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10736 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10740 * In cgroup mode, the pid argument is used to pass the fd
10741 * opened to the cgroup directory in cgroupfs. The cpu argument
10742 * designates the cpu on which to monitor threads from that
10745 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10748 if (flags & PERF_FLAG_FD_CLOEXEC)
10749 f_flags |= O_CLOEXEC;
10751 event_fd = get_unused_fd_flags(f_flags);
10755 if (group_fd != -1) {
10756 err = perf_fget_light(group_fd, &group);
10759 group_leader = group.file->private_data;
10760 if (flags & PERF_FLAG_FD_OUTPUT)
10761 output_event = group_leader;
10762 if (flags & PERF_FLAG_FD_NO_GROUP)
10763 group_leader = NULL;
10766 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10767 task = find_lively_task_by_vpid(pid);
10768 if (IS_ERR(task)) {
10769 err = PTR_ERR(task);
10774 if (task && group_leader &&
10775 group_leader->attr.inherit != attr.inherit) {
10781 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10786 * Reuse ptrace permission checks for now.
10788 * We must hold cred_guard_mutex across this and any potential
10789 * perf_install_in_context() call for this new event to
10790 * serialize against exec() altering our credentials (and the
10791 * perf_event_exit_task() that could imply).
10794 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10798 if (flags & PERF_FLAG_PID_CGROUP)
10801 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10802 NULL, NULL, cgroup_fd);
10803 if (IS_ERR(event)) {
10804 err = PTR_ERR(event);
10808 if (is_sampling_event(event)) {
10809 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10816 * Special case software events and allow them to be part of
10817 * any hardware group.
10821 if (attr.use_clockid) {
10822 err = perf_event_set_clock(event, attr.clockid);
10827 if (pmu->task_ctx_nr == perf_sw_context)
10828 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10830 if (group_leader) {
10831 if (is_software_event(event) &&
10832 !in_software_context(group_leader)) {
10834 * If the event is a sw event, but the group_leader
10835 * is on hw context.
10837 * Allow the addition of software events to hw
10838 * groups, this is safe because software events
10839 * never fail to schedule.
10841 pmu = group_leader->ctx->pmu;
10842 } else if (!is_software_event(event) &&
10843 is_software_event(group_leader) &&
10844 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10846 * In case the group is a pure software group, and we
10847 * try to add a hardware event, move the whole group to
10848 * the hardware context.
10855 * Get the target context (task or percpu):
10857 ctx = find_get_context(pmu, task, event);
10859 err = PTR_ERR(ctx);
10863 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10869 * Look up the group leader (we will attach this event to it):
10871 if (group_leader) {
10875 * Do not allow a recursive hierarchy (this new sibling
10876 * becoming part of another group-sibling):
10878 if (group_leader->group_leader != group_leader)
10881 /* All events in a group should have the same clock */
10882 if (group_leader->clock != event->clock)
10886 * Make sure we're both events for the same CPU;
10887 * grouping events for different CPUs is broken; since
10888 * you can never concurrently schedule them anyhow.
10890 if (group_leader->cpu != event->cpu)
10894 * Make sure we're both on the same task, or both
10897 if (group_leader->ctx->task != ctx->task)
10901 * Do not allow to attach to a group in a different task
10902 * or CPU context. If we're moving SW events, we'll fix
10903 * this up later, so allow that.
10905 if (!move_group && group_leader->ctx != ctx)
10909 * Only a group leader can be exclusive or pinned
10911 if (attr.exclusive || attr.pinned)
10915 if (output_event) {
10916 err = perf_event_set_output(event, output_event);
10921 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10923 if (IS_ERR(event_file)) {
10924 err = PTR_ERR(event_file);
10930 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10932 if (gctx->task == TASK_TOMBSTONE) {
10938 * Check if we raced against another sys_perf_event_open() call
10939 * moving the software group underneath us.
10941 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10943 * If someone moved the group out from under us, check
10944 * if this new event wound up on the same ctx, if so
10945 * its the regular !move_group case, otherwise fail.
10951 perf_event_ctx_unlock(group_leader, gctx);
10956 mutex_lock(&ctx->mutex);
10959 if (ctx->task == TASK_TOMBSTONE) {
10964 if (!perf_event_validate_size(event)) {
10971 * Check if the @cpu we're creating an event for is online.
10973 * We use the perf_cpu_context::ctx::mutex to serialize against
10974 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10976 struct perf_cpu_context *cpuctx =
10977 container_of(ctx, struct perf_cpu_context, ctx);
10979 if (!cpuctx->online) {
10987 * Must be under the same ctx::mutex as perf_install_in_context(),
10988 * because we need to serialize with concurrent event creation.
10990 if (!exclusive_event_installable(event, ctx)) {
10991 /* exclusive and group stuff are assumed mutually exclusive */
10992 WARN_ON_ONCE(move_group);
10998 WARN_ON_ONCE(ctx->parent_ctx);
11001 * This is the point on no return; we cannot fail hereafter. This is
11002 * where we start modifying current state.
11007 * See perf_event_ctx_lock() for comments on the details
11008 * of swizzling perf_event::ctx.
11010 perf_remove_from_context(group_leader, 0);
11013 for_each_sibling_event(sibling, group_leader) {
11014 perf_remove_from_context(sibling, 0);
11019 * Wait for everybody to stop referencing the events through
11020 * the old lists, before installing it on new lists.
11025 * Install the group siblings before the group leader.
11027 * Because a group leader will try and install the entire group
11028 * (through the sibling list, which is still in-tact), we can
11029 * end up with siblings installed in the wrong context.
11031 * By installing siblings first we NO-OP because they're not
11032 * reachable through the group lists.
11034 for_each_sibling_event(sibling, group_leader) {
11035 perf_event__state_init(sibling);
11036 perf_install_in_context(ctx, sibling, sibling->cpu);
11041 * Removing from the context ends up with disabled
11042 * event. What we want here is event in the initial
11043 * startup state, ready to be add into new context.
11045 perf_event__state_init(group_leader);
11046 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11051 * Precalculate sample_data sizes; do while holding ctx::mutex such
11052 * that we're serialized against further additions and before
11053 * perf_install_in_context() which is the point the event is active and
11054 * can use these values.
11056 perf_event__header_size(event);
11057 perf_event__id_header_size(event);
11059 event->owner = current;
11061 perf_install_in_context(ctx, event, event->cpu);
11062 perf_unpin_context(ctx);
11065 perf_event_ctx_unlock(group_leader, gctx);
11066 mutex_unlock(&ctx->mutex);
11069 mutex_unlock(&task->signal->cred_guard_mutex);
11070 put_task_struct(task);
11073 mutex_lock(¤t->perf_event_mutex);
11074 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11075 mutex_unlock(¤t->perf_event_mutex);
11078 * Drop the reference on the group_event after placing the
11079 * new event on the sibling_list. This ensures destruction
11080 * of the group leader will find the pointer to itself in
11081 * perf_group_detach().
11084 fd_install(event_fd, event_file);
11089 perf_event_ctx_unlock(group_leader, gctx);
11090 mutex_unlock(&ctx->mutex);
11094 perf_unpin_context(ctx);
11098 * If event_file is set, the fput() above will have called ->release()
11099 * and that will take care of freeing the event.
11105 mutex_unlock(&task->signal->cred_guard_mutex);
11108 put_task_struct(task);
11112 put_unused_fd(event_fd);
11117 * perf_event_create_kernel_counter
11119 * @attr: attributes of the counter to create
11120 * @cpu: cpu in which the counter is bound
11121 * @task: task to profile (NULL for percpu)
11123 struct perf_event *
11124 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11125 struct task_struct *task,
11126 perf_overflow_handler_t overflow_handler,
11129 struct perf_event_context *ctx;
11130 struct perf_event *event;
11134 * Get the target context (task or percpu):
11137 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11138 overflow_handler, context, -1);
11139 if (IS_ERR(event)) {
11140 err = PTR_ERR(event);
11144 /* Mark owner so we could distinguish it from user events. */
11145 event->owner = TASK_TOMBSTONE;
11147 ctx = find_get_context(event->pmu, task, event);
11149 err = PTR_ERR(ctx);
11153 WARN_ON_ONCE(ctx->parent_ctx);
11154 mutex_lock(&ctx->mutex);
11155 if (ctx->task == TASK_TOMBSTONE) {
11162 * Check if the @cpu we're creating an event for is online.
11164 * We use the perf_cpu_context::ctx::mutex to serialize against
11165 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11167 struct perf_cpu_context *cpuctx =
11168 container_of(ctx, struct perf_cpu_context, ctx);
11169 if (!cpuctx->online) {
11175 if (!exclusive_event_installable(event, ctx)) {
11180 perf_install_in_context(ctx, event, cpu);
11181 perf_unpin_context(ctx);
11182 mutex_unlock(&ctx->mutex);
11187 mutex_unlock(&ctx->mutex);
11188 perf_unpin_context(ctx);
11193 return ERR_PTR(err);
11195 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11197 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11199 struct perf_event_context *src_ctx;
11200 struct perf_event_context *dst_ctx;
11201 struct perf_event *event, *tmp;
11204 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11205 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11208 * See perf_event_ctx_lock() for comments on the details
11209 * of swizzling perf_event::ctx.
11211 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11212 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11214 perf_remove_from_context(event, 0);
11215 unaccount_event_cpu(event, src_cpu);
11217 list_add(&event->migrate_entry, &events);
11221 * Wait for the events to quiesce before re-instating them.
11226 * Re-instate events in 2 passes.
11228 * Skip over group leaders and only install siblings on this first
11229 * pass, siblings will not get enabled without a leader, however a
11230 * leader will enable its siblings, even if those are still on the old
11233 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11234 if (event->group_leader == event)
11237 list_del(&event->migrate_entry);
11238 if (event->state >= PERF_EVENT_STATE_OFF)
11239 event->state = PERF_EVENT_STATE_INACTIVE;
11240 account_event_cpu(event, dst_cpu);
11241 perf_install_in_context(dst_ctx, event, dst_cpu);
11246 * Once all the siblings are setup properly, install the group leaders
11249 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11250 list_del(&event->migrate_entry);
11251 if (event->state >= PERF_EVENT_STATE_OFF)
11252 event->state = PERF_EVENT_STATE_INACTIVE;
11253 account_event_cpu(event, dst_cpu);
11254 perf_install_in_context(dst_ctx, event, dst_cpu);
11257 mutex_unlock(&dst_ctx->mutex);
11258 mutex_unlock(&src_ctx->mutex);
11260 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11262 static void sync_child_event(struct perf_event *child_event,
11263 struct task_struct *child)
11265 struct perf_event *parent_event = child_event->parent;
11268 if (child_event->attr.inherit_stat)
11269 perf_event_read_event(child_event, child);
11271 child_val = perf_event_count(child_event);
11274 * Add back the child's count to the parent's count:
11276 atomic64_add(child_val, &parent_event->child_count);
11277 atomic64_add(child_event->total_time_enabled,
11278 &parent_event->child_total_time_enabled);
11279 atomic64_add(child_event->total_time_running,
11280 &parent_event->child_total_time_running);
11284 perf_event_exit_event(struct perf_event *child_event,
11285 struct perf_event_context *child_ctx,
11286 struct task_struct *child)
11288 struct perf_event *parent_event = child_event->parent;
11291 * Do not destroy the 'original' grouping; because of the context
11292 * switch optimization the original events could've ended up in a
11293 * random child task.
11295 * If we were to destroy the original group, all group related
11296 * operations would cease to function properly after this random
11299 * Do destroy all inherited groups, we don't care about those
11300 * and being thorough is better.
11302 raw_spin_lock_irq(&child_ctx->lock);
11303 WARN_ON_ONCE(child_ctx->is_active);
11306 perf_group_detach(child_event);
11307 list_del_event(child_event, child_ctx);
11308 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11309 raw_spin_unlock_irq(&child_ctx->lock);
11312 * Parent events are governed by their filedesc, retain them.
11314 if (!parent_event) {
11315 perf_event_wakeup(child_event);
11319 * Child events can be cleaned up.
11322 sync_child_event(child_event, child);
11325 * Remove this event from the parent's list
11327 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11328 mutex_lock(&parent_event->child_mutex);
11329 list_del_init(&child_event->child_list);
11330 mutex_unlock(&parent_event->child_mutex);
11333 * Kick perf_poll() for is_event_hup().
11335 perf_event_wakeup(parent_event);
11336 free_event(child_event);
11337 put_event(parent_event);
11340 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11342 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11343 struct perf_event *child_event, *next;
11345 WARN_ON_ONCE(child != current);
11347 child_ctx = perf_pin_task_context(child, ctxn);
11352 * In order to reduce the amount of tricky in ctx tear-down, we hold
11353 * ctx::mutex over the entire thing. This serializes against almost
11354 * everything that wants to access the ctx.
11356 * The exception is sys_perf_event_open() /
11357 * perf_event_create_kernel_count() which does find_get_context()
11358 * without ctx::mutex (it cannot because of the move_group double mutex
11359 * lock thing). See the comments in perf_install_in_context().
11361 mutex_lock(&child_ctx->mutex);
11364 * In a single ctx::lock section, de-schedule the events and detach the
11365 * context from the task such that we cannot ever get it scheduled back
11368 raw_spin_lock_irq(&child_ctx->lock);
11369 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11372 * Now that the context is inactive, destroy the task <-> ctx relation
11373 * and mark the context dead.
11375 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11376 put_ctx(child_ctx); /* cannot be last */
11377 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11378 put_task_struct(current); /* cannot be last */
11380 clone_ctx = unclone_ctx(child_ctx);
11381 raw_spin_unlock_irq(&child_ctx->lock);
11384 put_ctx(clone_ctx);
11387 * Report the task dead after unscheduling the events so that we
11388 * won't get any samples after PERF_RECORD_EXIT. We can however still
11389 * get a few PERF_RECORD_READ events.
11391 perf_event_task(child, child_ctx, 0);
11393 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11394 perf_event_exit_event(child_event, child_ctx, child);
11396 mutex_unlock(&child_ctx->mutex);
11398 put_ctx(child_ctx);
11402 * When a child task exits, feed back event values to parent events.
11404 * Can be called with cred_guard_mutex held when called from
11405 * install_exec_creds().
11407 void perf_event_exit_task(struct task_struct *child)
11409 struct perf_event *event, *tmp;
11412 mutex_lock(&child->perf_event_mutex);
11413 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11415 list_del_init(&event->owner_entry);
11418 * Ensure the list deletion is visible before we clear
11419 * the owner, closes a race against perf_release() where
11420 * we need to serialize on the owner->perf_event_mutex.
11422 smp_store_release(&event->owner, NULL);
11424 mutex_unlock(&child->perf_event_mutex);
11426 for_each_task_context_nr(ctxn)
11427 perf_event_exit_task_context(child, ctxn);
11430 * The perf_event_exit_task_context calls perf_event_task
11431 * with child's task_ctx, which generates EXIT events for
11432 * child contexts and sets child->perf_event_ctxp[] to NULL.
11433 * At this point we need to send EXIT events to cpu contexts.
11435 perf_event_task(child, NULL, 0);
11438 static void perf_free_event(struct perf_event *event,
11439 struct perf_event_context *ctx)
11441 struct perf_event *parent = event->parent;
11443 if (WARN_ON_ONCE(!parent))
11446 mutex_lock(&parent->child_mutex);
11447 list_del_init(&event->child_list);
11448 mutex_unlock(&parent->child_mutex);
11452 raw_spin_lock_irq(&ctx->lock);
11453 perf_group_detach(event);
11454 list_del_event(event, ctx);
11455 raw_spin_unlock_irq(&ctx->lock);
11460 * Free an unexposed, unused context as created by inheritance by
11461 * perf_event_init_task below, used by fork() in case of fail.
11463 * Not all locks are strictly required, but take them anyway to be nice and
11464 * help out with the lockdep assertions.
11466 void perf_event_free_task(struct task_struct *task)
11468 struct perf_event_context *ctx;
11469 struct perf_event *event, *tmp;
11472 for_each_task_context_nr(ctxn) {
11473 ctx = task->perf_event_ctxp[ctxn];
11477 mutex_lock(&ctx->mutex);
11478 raw_spin_lock_irq(&ctx->lock);
11480 * Destroy the task <-> ctx relation and mark the context dead.
11482 * This is important because even though the task hasn't been
11483 * exposed yet the context has been (through child_list).
11485 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11486 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11487 put_task_struct(task); /* cannot be last */
11488 raw_spin_unlock_irq(&ctx->lock);
11490 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11491 perf_free_event(event, ctx);
11493 mutex_unlock(&ctx->mutex);
11498 void perf_event_delayed_put(struct task_struct *task)
11502 for_each_task_context_nr(ctxn)
11503 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11506 struct file *perf_event_get(unsigned int fd)
11510 file = fget_raw(fd);
11512 return ERR_PTR(-EBADF);
11514 if (file->f_op != &perf_fops) {
11516 return ERR_PTR(-EBADF);
11522 const struct perf_event *perf_get_event(struct file *file)
11524 if (file->f_op != &perf_fops)
11525 return ERR_PTR(-EINVAL);
11527 return file->private_data;
11530 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11533 return ERR_PTR(-EINVAL);
11535 return &event->attr;
11539 * Inherit an event from parent task to child task.
11542 * - valid pointer on success
11543 * - NULL for orphaned events
11544 * - IS_ERR() on error
11546 static struct perf_event *
11547 inherit_event(struct perf_event *parent_event,
11548 struct task_struct *parent,
11549 struct perf_event_context *parent_ctx,
11550 struct task_struct *child,
11551 struct perf_event *group_leader,
11552 struct perf_event_context *child_ctx)
11554 enum perf_event_state parent_state = parent_event->state;
11555 struct perf_event *child_event;
11556 unsigned long flags;
11559 * Instead of creating recursive hierarchies of events,
11560 * we link inherited events back to the original parent,
11561 * which has a filp for sure, which we use as the reference
11564 if (parent_event->parent)
11565 parent_event = parent_event->parent;
11567 child_event = perf_event_alloc(&parent_event->attr,
11570 group_leader, parent_event,
11572 if (IS_ERR(child_event))
11573 return child_event;
11576 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11577 !child_ctx->task_ctx_data) {
11578 struct pmu *pmu = child_event->pmu;
11580 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11582 if (!child_ctx->task_ctx_data) {
11583 free_event(child_event);
11589 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11590 * must be under the same lock in order to serialize against
11591 * perf_event_release_kernel(), such that either we must observe
11592 * is_orphaned_event() or they will observe us on the child_list.
11594 mutex_lock(&parent_event->child_mutex);
11595 if (is_orphaned_event(parent_event) ||
11596 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11597 mutex_unlock(&parent_event->child_mutex);
11598 /* task_ctx_data is freed with child_ctx */
11599 free_event(child_event);
11603 get_ctx(child_ctx);
11606 * Make the child state follow the state of the parent event,
11607 * not its attr.disabled bit. We hold the parent's mutex,
11608 * so we won't race with perf_event_{en, dis}able_family.
11610 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11611 child_event->state = PERF_EVENT_STATE_INACTIVE;
11613 child_event->state = PERF_EVENT_STATE_OFF;
11615 if (parent_event->attr.freq) {
11616 u64 sample_period = parent_event->hw.sample_period;
11617 struct hw_perf_event *hwc = &child_event->hw;
11619 hwc->sample_period = sample_period;
11620 hwc->last_period = sample_period;
11622 local64_set(&hwc->period_left, sample_period);
11625 child_event->ctx = child_ctx;
11626 child_event->overflow_handler = parent_event->overflow_handler;
11627 child_event->overflow_handler_context
11628 = parent_event->overflow_handler_context;
11631 * Precalculate sample_data sizes
11633 perf_event__header_size(child_event);
11634 perf_event__id_header_size(child_event);
11637 * Link it up in the child's context:
11639 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11640 add_event_to_ctx(child_event, child_ctx);
11641 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11644 * Link this into the parent event's child list
11646 list_add_tail(&child_event->child_list, &parent_event->child_list);
11647 mutex_unlock(&parent_event->child_mutex);
11649 return child_event;
11653 * Inherits an event group.
11655 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11656 * This matches with perf_event_release_kernel() removing all child events.
11662 static int inherit_group(struct perf_event *parent_event,
11663 struct task_struct *parent,
11664 struct perf_event_context *parent_ctx,
11665 struct task_struct *child,
11666 struct perf_event_context *child_ctx)
11668 struct perf_event *leader;
11669 struct perf_event *sub;
11670 struct perf_event *child_ctr;
11672 leader = inherit_event(parent_event, parent, parent_ctx,
11673 child, NULL, child_ctx);
11674 if (IS_ERR(leader))
11675 return PTR_ERR(leader);
11677 * @leader can be NULL here because of is_orphaned_event(). In this
11678 * case inherit_event() will create individual events, similar to what
11679 * perf_group_detach() would do anyway.
11681 for_each_sibling_event(sub, parent_event) {
11682 child_ctr = inherit_event(sub, parent, parent_ctx,
11683 child, leader, child_ctx);
11684 if (IS_ERR(child_ctr))
11685 return PTR_ERR(child_ctr);
11691 * Creates the child task context and tries to inherit the event-group.
11693 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11694 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11695 * consistent with perf_event_release_kernel() removing all child events.
11702 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11703 struct perf_event_context *parent_ctx,
11704 struct task_struct *child, int ctxn,
11705 int *inherited_all)
11708 struct perf_event_context *child_ctx;
11710 if (!event->attr.inherit) {
11711 *inherited_all = 0;
11715 child_ctx = child->perf_event_ctxp[ctxn];
11718 * This is executed from the parent task context, so
11719 * inherit events that have been marked for cloning.
11720 * First allocate and initialize a context for the
11723 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11727 child->perf_event_ctxp[ctxn] = child_ctx;
11730 ret = inherit_group(event, parent, parent_ctx,
11734 *inherited_all = 0;
11740 * Initialize the perf_event context in task_struct
11742 static int perf_event_init_context(struct task_struct *child, int ctxn)
11744 struct perf_event_context *child_ctx, *parent_ctx;
11745 struct perf_event_context *cloned_ctx;
11746 struct perf_event *event;
11747 struct task_struct *parent = current;
11748 int inherited_all = 1;
11749 unsigned long flags;
11752 if (likely(!parent->perf_event_ctxp[ctxn]))
11756 * If the parent's context is a clone, pin it so it won't get
11757 * swapped under us.
11759 parent_ctx = perf_pin_task_context(parent, ctxn);
11764 * No need to check if parent_ctx != NULL here; since we saw
11765 * it non-NULL earlier, the only reason for it to become NULL
11766 * is if we exit, and since we're currently in the middle of
11767 * a fork we can't be exiting at the same time.
11771 * Lock the parent list. No need to lock the child - not PID
11772 * hashed yet and not running, so nobody can access it.
11774 mutex_lock(&parent_ctx->mutex);
11777 * We dont have to disable NMIs - we are only looking at
11778 * the list, not manipulating it:
11780 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11781 ret = inherit_task_group(event, parent, parent_ctx,
11782 child, ctxn, &inherited_all);
11788 * We can't hold ctx->lock when iterating the ->flexible_group list due
11789 * to allocations, but we need to prevent rotation because
11790 * rotate_ctx() will change the list from interrupt context.
11792 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11793 parent_ctx->rotate_disable = 1;
11794 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11796 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11797 ret = inherit_task_group(event, parent, parent_ctx,
11798 child, ctxn, &inherited_all);
11803 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11804 parent_ctx->rotate_disable = 0;
11806 child_ctx = child->perf_event_ctxp[ctxn];
11808 if (child_ctx && inherited_all) {
11810 * Mark the child context as a clone of the parent
11811 * context, or of whatever the parent is a clone of.
11813 * Note that if the parent is a clone, the holding of
11814 * parent_ctx->lock avoids it from being uncloned.
11816 cloned_ctx = parent_ctx->parent_ctx;
11818 child_ctx->parent_ctx = cloned_ctx;
11819 child_ctx->parent_gen = parent_ctx->parent_gen;
11821 child_ctx->parent_ctx = parent_ctx;
11822 child_ctx->parent_gen = parent_ctx->generation;
11824 get_ctx(child_ctx->parent_ctx);
11827 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11829 mutex_unlock(&parent_ctx->mutex);
11831 perf_unpin_context(parent_ctx);
11832 put_ctx(parent_ctx);
11838 * Initialize the perf_event context in task_struct
11840 int perf_event_init_task(struct task_struct *child)
11844 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11845 mutex_init(&child->perf_event_mutex);
11846 INIT_LIST_HEAD(&child->perf_event_list);
11848 for_each_task_context_nr(ctxn) {
11849 ret = perf_event_init_context(child, ctxn);
11851 perf_event_free_task(child);
11859 static void __init perf_event_init_all_cpus(void)
11861 struct swevent_htable *swhash;
11864 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11866 for_each_possible_cpu(cpu) {
11867 swhash = &per_cpu(swevent_htable, cpu);
11868 mutex_init(&swhash->hlist_mutex);
11869 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11871 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11872 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11874 #ifdef CONFIG_CGROUP_PERF
11875 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11877 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11881 void perf_swevent_init_cpu(unsigned int cpu)
11883 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11885 mutex_lock(&swhash->hlist_mutex);
11886 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11887 struct swevent_hlist *hlist;
11889 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11891 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11893 mutex_unlock(&swhash->hlist_mutex);
11896 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11897 static void __perf_event_exit_context(void *__info)
11899 struct perf_event_context *ctx = __info;
11900 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11901 struct perf_event *event;
11903 raw_spin_lock(&ctx->lock);
11904 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11905 list_for_each_entry(event, &ctx->event_list, event_entry)
11906 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11907 raw_spin_unlock(&ctx->lock);
11910 static void perf_event_exit_cpu_context(int cpu)
11912 struct perf_cpu_context *cpuctx;
11913 struct perf_event_context *ctx;
11916 mutex_lock(&pmus_lock);
11917 list_for_each_entry(pmu, &pmus, entry) {
11918 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11919 ctx = &cpuctx->ctx;
11921 mutex_lock(&ctx->mutex);
11922 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11923 cpuctx->online = 0;
11924 mutex_unlock(&ctx->mutex);
11926 cpumask_clear_cpu(cpu, perf_online_mask);
11927 mutex_unlock(&pmus_lock);
11931 static void perf_event_exit_cpu_context(int cpu) { }
11935 int perf_event_init_cpu(unsigned int cpu)
11937 struct perf_cpu_context *cpuctx;
11938 struct perf_event_context *ctx;
11941 perf_swevent_init_cpu(cpu);
11943 mutex_lock(&pmus_lock);
11944 cpumask_set_cpu(cpu, perf_online_mask);
11945 list_for_each_entry(pmu, &pmus, entry) {
11946 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11947 ctx = &cpuctx->ctx;
11949 mutex_lock(&ctx->mutex);
11950 cpuctx->online = 1;
11951 mutex_unlock(&ctx->mutex);
11953 mutex_unlock(&pmus_lock);
11958 int perf_event_exit_cpu(unsigned int cpu)
11960 perf_event_exit_cpu_context(cpu);
11965 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11969 for_each_online_cpu(cpu)
11970 perf_event_exit_cpu(cpu);
11976 * Run the perf reboot notifier at the very last possible moment so that
11977 * the generic watchdog code runs as long as possible.
11979 static struct notifier_block perf_reboot_notifier = {
11980 .notifier_call = perf_reboot,
11981 .priority = INT_MIN,
11984 void __init perf_event_init(void)
11988 idr_init(&pmu_idr);
11990 perf_event_init_all_cpus();
11991 init_srcu_struct(&pmus_srcu);
11992 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11993 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11994 perf_pmu_register(&perf_task_clock, NULL, -1);
11995 perf_tp_register();
11996 perf_event_init_cpu(smp_processor_id());
11997 register_reboot_notifier(&perf_reboot_notifier);
11999 ret = init_hw_breakpoint();
12000 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12003 * Build time assertion that we keep the data_head at the intended
12004 * location. IOW, validation we got the __reserved[] size right.
12006 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12010 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12013 struct perf_pmu_events_attr *pmu_attr =
12014 container_of(attr, struct perf_pmu_events_attr, attr);
12016 if (pmu_attr->event_str)
12017 return sprintf(page, "%s\n", pmu_attr->event_str);
12021 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12023 static int __init perf_event_sysfs_init(void)
12028 mutex_lock(&pmus_lock);
12030 ret = bus_register(&pmu_bus);
12034 list_for_each_entry(pmu, &pmus, entry) {
12035 if (!pmu->name || pmu->type < 0)
12038 ret = pmu_dev_alloc(pmu);
12039 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12041 pmu_bus_running = 1;
12045 mutex_unlock(&pmus_lock);
12049 device_initcall(perf_event_sysfs_init);
12051 #ifdef CONFIG_CGROUP_PERF
12052 static struct cgroup_subsys_state *
12053 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12055 struct perf_cgroup *jc;
12057 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12059 return ERR_PTR(-ENOMEM);
12061 jc->info = alloc_percpu(struct perf_cgroup_info);
12064 return ERR_PTR(-ENOMEM);
12070 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12072 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12074 free_percpu(jc->info);
12078 static int __perf_cgroup_move(void *info)
12080 struct task_struct *task = info;
12082 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12087 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12089 struct task_struct *task;
12090 struct cgroup_subsys_state *css;
12092 cgroup_taskset_for_each(task, css, tset)
12093 task_function_call(task, __perf_cgroup_move, task);
12096 struct cgroup_subsys perf_event_cgrp_subsys = {
12097 .css_alloc = perf_cgroup_css_alloc,
12098 .css_free = perf_cgroup_css_free,
12099 .attach = perf_cgroup_attach,
12101 * Implicitly enable on dfl hierarchy so that perf events can
12102 * always be filtered by cgroup2 path as long as perf_event
12103 * controller is not mounted on a legacy hierarchy.
12105 .implicit_on_dfl = true,
12108 #endif /* CONFIG_CGROUP_PERF */