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 (READ_ONCE(event->pending_disable) >= 0) {
2013 WRITE_ONCE(event->pending_disable, -1);
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 WRITE_ONCE(event->pending_disable, smp_processor_id());
2202 /* can fail, see perf_pending_event_disable() */
2203 irq_work_queue(&event->pending);
2206 static void perf_set_shadow_time(struct perf_event *event,
2207 struct perf_event_context *ctx)
2210 * use the correct time source for the time snapshot
2212 * We could get by without this by leveraging the
2213 * fact that to get to this function, the caller
2214 * has most likely already called update_context_time()
2215 * and update_cgrp_time_xx() and thus both timestamp
2216 * are identical (or very close). Given that tstamp is,
2217 * already adjusted for cgroup, we could say that:
2218 * tstamp - ctx->timestamp
2220 * tstamp - cgrp->timestamp.
2222 * Then, in perf_output_read(), the calculation would
2223 * work with no changes because:
2224 * - event is guaranteed scheduled in
2225 * - no scheduled out in between
2226 * - thus the timestamp would be the same
2228 * But this is a bit hairy.
2230 * So instead, we have an explicit cgroup call to remain
2231 * within the time time source all along. We believe it
2232 * is cleaner and simpler to understand.
2234 if (is_cgroup_event(event))
2235 perf_cgroup_set_shadow_time(event, event->tstamp);
2237 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2240 #define MAX_INTERRUPTS (~0ULL)
2242 static void perf_log_throttle(struct perf_event *event, int enable);
2243 static void perf_log_itrace_start(struct perf_event *event);
2246 event_sched_in(struct perf_event *event,
2247 struct perf_cpu_context *cpuctx,
2248 struct perf_event_context *ctx)
2252 lockdep_assert_held(&ctx->lock);
2254 if (event->state <= PERF_EVENT_STATE_OFF)
2257 WRITE_ONCE(event->oncpu, smp_processor_id());
2259 * Order event::oncpu write to happen before the ACTIVE state is
2260 * visible. This allows perf_event_{stop,read}() to observe the correct
2261 * ->oncpu if it sees ACTIVE.
2264 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2267 * Unthrottle events, since we scheduled we might have missed several
2268 * ticks already, also for a heavily scheduling task there is little
2269 * guarantee it'll get a tick in a timely manner.
2271 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2272 perf_log_throttle(event, 1);
2273 event->hw.interrupts = 0;
2276 perf_pmu_disable(event->pmu);
2278 perf_set_shadow_time(event, ctx);
2280 perf_log_itrace_start(event);
2282 if (event->pmu->add(event, PERF_EF_START)) {
2283 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2289 if (!is_software_event(event))
2290 cpuctx->active_oncpu++;
2291 if (!ctx->nr_active++)
2292 perf_event_ctx_activate(ctx);
2293 if (event->attr.freq && event->attr.sample_freq)
2296 if (event->attr.exclusive)
2297 cpuctx->exclusive = 1;
2300 perf_pmu_enable(event->pmu);
2306 group_sched_in(struct perf_event *group_event,
2307 struct perf_cpu_context *cpuctx,
2308 struct perf_event_context *ctx)
2310 struct perf_event *event, *partial_group = NULL;
2311 struct pmu *pmu = ctx->pmu;
2313 if (group_event->state == PERF_EVENT_STATE_OFF)
2316 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2318 if (event_sched_in(group_event, cpuctx, ctx)) {
2319 pmu->cancel_txn(pmu);
2320 perf_mux_hrtimer_restart(cpuctx);
2325 * Schedule in siblings as one group (if any):
2327 for_each_sibling_event(event, group_event) {
2328 if (event_sched_in(event, cpuctx, ctx)) {
2329 partial_group = event;
2334 if (!pmu->commit_txn(pmu))
2339 * Groups can be scheduled in as one unit only, so undo any
2340 * partial group before returning:
2341 * The events up to the failed event are scheduled out normally.
2343 for_each_sibling_event(event, group_event) {
2344 if (event == partial_group)
2347 event_sched_out(event, cpuctx, ctx);
2349 event_sched_out(group_event, cpuctx, ctx);
2351 pmu->cancel_txn(pmu);
2353 perf_mux_hrtimer_restart(cpuctx);
2359 * Work out whether we can put this event group on the CPU now.
2361 static int group_can_go_on(struct perf_event *event,
2362 struct perf_cpu_context *cpuctx,
2366 * Groups consisting entirely of software events can always go on.
2368 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2371 * If an exclusive group is already on, no other hardware
2374 if (cpuctx->exclusive)
2377 * If this group is exclusive and there are already
2378 * events on the CPU, it can't go on.
2380 if (event->attr.exclusive && cpuctx->active_oncpu)
2383 * Otherwise, try to add it if all previous groups were able
2389 static void add_event_to_ctx(struct perf_event *event,
2390 struct perf_event_context *ctx)
2392 list_add_event(event, ctx);
2393 perf_group_attach(event);
2396 static void ctx_sched_out(struct perf_event_context *ctx,
2397 struct perf_cpu_context *cpuctx,
2398 enum event_type_t event_type);
2400 ctx_sched_in(struct perf_event_context *ctx,
2401 struct perf_cpu_context *cpuctx,
2402 enum event_type_t event_type,
2403 struct task_struct *task);
2405 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2406 struct perf_event_context *ctx,
2407 enum event_type_t event_type)
2409 if (!cpuctx->task_ctx)
2412 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2415 ctx_sched_out(ctx, cpuctx, event_type);
2418 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2419 struct perf_event_context *ctx,
2420 struct task_struct *task)
2422 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2424 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2425 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2427 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2431 * We want to maintain the following priority of scheduling:
2432 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2433 * - task pinned (EVENT_PINNED)
2434 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2435 * - task flexible (EVENT_FLEXIBLE).
2437 * In order to avoid unscheduling and scheduling back in everything every
2438 * time an event is added, only do it for the groups of equal priority and
2441 * This can be called after a batch operation on task events, in which case
2442 * event_type is a bit mask of the types of events involved. For CPU events,
2443 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2445 static void ctx_resched(struct perf_cpu_context *cpuctx,
2446 struct perf_event_context *task_ctx,
2447 enum event_type_t event_type)
2449 enum event_type_t ctx_event_type;
2450 bool cpu_event = !!(event_type & EVENT_CPU);
2453 * If pinned groups are involved, flexible groups also need to be
2456 if (event_type & EVENT_PINNED)
2457 event_type |= EVENT_FLEXIBLE;
2459 ctx_event_type = event_type & EVENT_ALL;
2461 perf_pmu_disable(cpuctx->ctx.pmu);
2463 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2466 * Decide which cpu ctx groups to schedule out based on the types
2467 * of events that caused rescheduling:
2468 * - EVENT_CPU: schedule out corresponding groups;
2469 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2470 * - otherwise, do nothing more.
2473 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2474 else if (ctx_event_type & EVENT_PINNED)
2475 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2477 perf_event_sched_in(cpuctx, task_ctx, current);
2478 perf_pmu_enable(cpuctx->ctx.pmu);
2481 void perf_pmu_resched(struct pmu *pmu)
2483 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2484 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2486 perf_ctx_lock(cpuctx, task_ctx);
2487 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2488 perf_ctx_unlock(cpuctx, task_ctx);
2492 * Cross CPU call to install and enable a performance event
2494 * Very similar to remote_function() + event_function() but cannot assume that
2495 * things like ctx->is_active and cpuctx->task_ctx are set.
2497 static int __perf_install_in_context(void *info)
2499 struct perf_event *event = info;
2500 struct perf_event_context *ctx = event->ctx;
2501 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2502 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2503 bool reprogram = true;
2506 raw_spin_lock(&cpuctx->ctx.lock);
2508 raw_spin_lock(&ctx->lock);
2511 reprogram = (ctx->task == current);
2514 * If the task is running, it must be running on this CPU,
2515 * otherwise we cannot reprogram things.
2517 * If its not running, we don't care, ctx->lock will
2518 * serialize against it becoming runnable.
2520 if (task_curr(ctx->task) && !reprogram) {
2525 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2526 } else if (task_ctx) {
2527 raw_spin_lock(&task_ctx->lock);
2530 #ifdef CONFIG_CGROUP_PERF
2531 if (is_cgroup_event(event)) {
2533 * If the current cgroup doesn't match the event's
2534 * cgroup, we should not try to schedule it.
2536 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2537 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2538 event->cgrp->css.cgroup);
2543 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2544 add_event_to_ctx(event, ctx);
2545 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2547 add_event_to_ctx(event, ctx);
2551 perf_ctx_unlock(cpuctx, task_ctx);
2557 * Attach a performance event to a context.
2559 * Very similar to event_function_call, see comment there.
2562 perf_install_in_context(struct perf_event_context *ctx,
2563 struct perf_event *event,
2566 struct task_struct *task = READ_ONCE(ctx->task);
2568 lockdep_assert_held(&ctx->mutex);
2570 if (event->cpu != -1)
2574 * Ensures that if we can observe event->ctx, both the event and ctx
2575 * will be 'complete'. See perf_iterate_sb_cpu().
2577 smp_store_release(&event->ctx, ctx);
2580 cpu_function_call(cpu, __perf_install_in_context, event);
2585 * Should not happen, we validate the ctx is still alive before calling.
2587 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2591 * Installing events is tricky because we cannot rely on ctx->is_active
2592 * to be set in case this is the nr_events 0 -> 1 transition.
2594 * Instead we use task_curr(), which tells us if the task is running.
2595 * However, since we use task_curr() outside of rq::lock, we can race
2596 * against the actual state. This means the result can be wrong.
2598 * If we get a false positive, we retry, this is harmless.
2600 * If we get a false negative, things are complicated. If we are after
2601 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2602 * value must be correct. If we're before, it doesn't matter since
2603 * perf_event_context_sched_in() will program the counter.
2605 * However, this hinges on the remote context switch having observed
2606 * our task->perf_event_ctxp[] store, such that it will in fact take
2607 * ctx::lock in perf_event_context_sched_in().
2609 * We do this by task_function_call(), if the IPI fails to hit the task
2610 * we know any future context switch of task must see the
2611 * perf_event_ctpx[] store.
2615 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2616 * task_cpu() load, such that if the IPI then does not find the task
2617 * running, a future context switch of that task must observe the
2622 if (!task_function_call(task, __perf_install_in_context, event))
2625 raw_spin_lock_irq(&ctx->lock);
2627 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2629 * Cannot happen because we already checked above (which also
2630 * cannot happen), and we hold ctx->mutex, which serializes us
2631 * against perf_event_exit_task_context().
2633 raw_spin_unlock_irq(&ctx->lock);
2637 * If the task is not running, ctx->lock will avoid it becoming so,
2638 * thus we can safely install the event.
2640 if (task_curr(task)) {
2641 raw_spin_unlock_irq(&ctx->lock);
2644 add_event_to_ctx(event, ctx);
2645 raw_spin_unlock_irq(&ctx->lock);
2649 * Cross CPU call to enable a performance event
2651 static void __perf_event_enable(struct perf_event *event,
2652 struct perf_cpu_context *cpuctx,
2653 struct perf_event_context *ctx,
2656 struct perf_event *leader = event->group_leader;
2657 struct perf_event_context *task_ctx;
2659 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2660 event->state <= PERF_EVENT_STATE_ERROR)
2664 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2666 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2668 if (!ctx->is_active)
2671 if (!event_filter_match(event)) {
2672 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2677 * If the event is in a group and isn't the group leader,
2678 * then don't put it on unless the group is on.
2680 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2681 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2685 task_ctx = cpuctx->task_ctx;
2687 WARN_ON_ONCE(task_ctx != ctx);
2689 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2695 * If event->ctx is a cloned context, callers must make sure that
2696 * every task struct that event->ctx->task could possibly point to
2697 * remains valid. This condition is satisfied when called through
2698 * perf_event_for_each_child or perf_event_for_each as described
2699 * for perf_event_disable.
2701 static void _perf_event_enable(struct perf_event *event)
2703 struct perf_event_context *ctx = event->ctx;
2705 raw_spin_lock_irq(&ctx->lock);
2706 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2707 event->state < PERF_EVENT_STATE_ERROR) {
2708 raw_spin_unlock_irq(&ctx->lock);
2713 * If the event is in error state, clear that first.
2715 * That way, if we see the event in error state below, we know that it
2716 * has gone back into error state, as distinct from the task having
2717 * been scheduled away before the cross-call arrived.
2719 if (event->state == PERF_EVENT_STATE_ERROR)
2720 event->state = PERF_EVENT_STATE_OFF;
2721 raw_spin_unlock_irq(&ctx->lock);
2723 event_function_call(event, __perf_event_enable, NULL);
2727 * See perf_event_disable();
2729 void perf_event_enable(struct perf_event *event)
2731 struct perf_event_context *ctx;
2733 ctx = perf_event_ctx_lock(event);
2734 _perf_event_enable(event);
2735 perf_event_ctx_unlock(event, ctx);
2737 EXPORT_SYMBOL_GPL(perf_event_enable);
2739 struct stop_event_data {
2740 struct perf_event *event;
2741 unsigned int restart;
2744 static int __perf_event_stop(void *info)
2746 struct stop_event_data *sd = info;
2747 struct perf_event *event = sd->event;
2749 /* if it's already INACTIVE, do nothing */
2750 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2753 /* matches smp_wmb() in event_sched_in() */
2757 * There is a window with interrupts enabled before we get here,
2758 * so we need to check again lest we try to stop another CPU's event.
2760 if (READ_ONCE(event->oncpu) != smp_processor_id())
2763 event->pmu->stop(event, PERF_EF_UPDATE);
2766 * May race with the actual stop (through perf_pmu_output_stop()),
2767 * but it is only used for events with AUX ring buffer, and such
2768 * events will refuse to restart because of rb::aux_mmap_count==0,
2769 * see comments in perf_aux_output_begin().
2771 * Since this is happening on an event-local CPU, no trace is lost
2775 event->pmu->start(event, 0);
2780 static int perf_event_stop(struct perf_event *event, int restart)
2782 struct stop_event_data sd = {
2789 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2792 /* matches smp_wmb() in event_sched_in() */
2796 * We only want to restart ACTIVE events, so if the event goes
2797 * inactive here (event->oncpu==-1), there's nothing more to do;
2798 * fall through with ret==-ENXIO.
2800 ret = cpu_function_call(READ_ONCE(event->oncpu),
2801 __perf_event_stop, &sd);
2802 } while (ret == -EAGAIN);
2808 * In order to contain the amount of racy and tricky in the address filter
2809 * configuration management, it is a two part process:
2811 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2812 * we update the addresses of corresponding vmas in
2813 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2814 * (p2) when an event is scheduled in (pmu::add), it calls
2815 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2816 * if the generation has changed since the previous call.
2818 * If (p1) happens while the event is active, we restart it to force (p2).
2820 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2821 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2823 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2824 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2826 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2829 void perf_event_addr_filters_sync(struct perf_event *event)
2831 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2833 if (!has_addr_filter(event))
2836 raw_spin_lock(&ifh->lock);
2837 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2838 event->pmu->addr_filters_sync(event);
2839 event->hw.addr_filters_gen = event->addr_filters_gen;
2841 raw_spin_unlock(&ifh->lock);
2843 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2845 static int _perf_event_refresh(struct perf_event *event, int refresh)
2848 * not supported on inherited events
2850 if (event->attr.inherit || !is_sampling_event(event))
2853 atomic_add(refresh, &event->event_limit);
2854 _perf_event_enable(event);
2860 * See perf_event_disable()
2862 int perf_event_refresh(struct perf_event *event, int refresh)
2864 struct perf_event_context *ctx;
2867 ctx = perf_event_ctx_lock(event);
2868 ret = _perf_event_refresh(event, refresh);
2869 perf_event_ctx_unlock(event, ctx);
2873 EXPORT_SYMBOL_GPL(perf_event_refresh);
2875 static int perf_event_modify_breakpoint(struct perf_event *bp,
2876 struct perf_event_attr *attr)
2880 _perf_event_disable(bp);
2882 err = modify_user_hw_breakpoint_check(bp, attr, true);
2884 if (!bp->attr.disabled)
2885 _perf_event_enable(bp);
2890 static int perf_event_modify_attr(struct perf_event *event,
2891 struct perf_event_attr *attr)
2893 if (event->attr.type != attr->type)
2896 switch (event->attr.type) {
2897 case PERF_TYPE_BREAKPOINT:
2898 return perf_event_modify_breakpoint(event, attr);
2900 /* Place holder for future additions. */
2905 static void ctx_sched_out(struct perf_event_context *ctx,
2906 struct perf_cpu_context *cpuctx,
2907 enum event_type_t event_type)
2909 struct perf_event *event, *tmp;
2910 int is_active = ctx->is_active;
2912 lockdep_assert_held(&ctx->lock);
2914 if (likely(!ctx->nr_events)) {
2916 * See __perf_remove_from_context().
2918 WARN_ON_ONCE(ctx->is_active);
2920 WARN_ON_ONCE(cpuctx->task_ctx);
2924 ctx->is_active &= ~event_type;
2925 if (!(ctx->is_active & EVENT_ALL))
2929 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2930 if (!ctx->is_active)
2931 cpuctx->task_ctx = NULL;
2935 * Always update time if it was set; not only when it changes.
2936 * Otherwise we can 'forget' to update time for any but the last
2937 * context we sched out. For example:
2939 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2940 * ctx_sched_out(.event_type = EVENT_PINNED)
2942 * would only update time for the pinned events.
2944 if (is_active & EVENT_TIME) {
2945 /* update (and stop) ctx time */
2946 update_context_time(ctx);
2947 update_cgrp_time_from_cpuctx(cpuctx);
2950 is_active ^= ctx->is_active; /* changed bits */
2952 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2956 * If we had been multiplexing, no rotations are necessary, now no events
2959 ctx->rotate_necessary = 0;
2961 perf_pmu_disable(ctx->pmu);
2962 if (is_active & EVENT_PINNED) {
2963 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2964 group_sched_out(event, cpuctx, ctx);
2967 if (is_active & EVENT_FLEXIBLE) {
2968 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2969 group_sched_out(event, cpuctx, ctx);
2971 perf_pmu_enable(ctx->pmu);
2975 * Test whether two contexts are equivalent, i.e. whether they have both been
2976 * cloned from the same version of the same context.
2978 * Equivalence is measured using a generation number in the context that is
2979 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2980 * and list_del_event().
2982 static int context_equiv(struct perf_event_context *ctx1,
2983 struct perf_event_context *ctx2)
2985 lockdep_assert_held(&ctx1->lock);
2986 lockdep_assert_held(&ctx2->lock);
2988 /* Pinning disables the swap optimization */
2989 if (ctx1->pin_count || ctx2->pin_count)
2992 /* If ctx1 is the parent of ctx2 */
2993 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2996 /* If ctx2 is the parent of ctx1 */
2997 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3001 * If ctx1 and ctx2 have the same parent; we flatten the parent
3002 * hierarchy, see perf_event_init_context().
3004 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3005 ctx1->parent_gen == ctx2->parent_gen)
3012 static void __perf_event_sync_stat(struct perf_event *event,
3013 struct perf_event *next_event)
3017 if (!event->attr.inherit_stat)
3021 * Update the event value, we cannot use perf_event_read()
3022 * because we're in the middle of a context switch and have IRQs
3023 * disabled, which upsets smp_call_function_single(), however
3024 * we know the event must be on the current CPU, therefore we
3025 * don't need to use it.
3027 if (event->state == PERF_EVENT_STATE_ACTIVE)
3028 event->pmu->read(event);
3030 perf_event_update_time(event);
3033 * In order to keep per-task stats reliable we need to flip the event
3034 * values when we flip the contexts.
3036 value = local64_read(&next_event->count);
3037 value = local64_xchg(&event->count, value);
3038 local64_set(&next_event->count, value);
3040 swap(event->total_time_enabled, next_event->total_time_enabled);
3041 swap(event->total_time_running, next_event->total_time_running);
3044 * Since we swizzled the values, update the user visible data too.
3046 perf_event_update_userpage(event);
3047 perf_event_update_userpage(next_event);
3050 static void perf_event_sync_stat(struct perf_event_context *ctx,
3051 struct perf_event_context *next_ctx)
3053 struct perf_event *event, *next_event;
3058 update_context_time(ctx);
3060 event = list_first_entry(&ctx->event_list,
3061 struct perf_event, event_entry);
3063 next_event = list_first_entry(&next_ctx->event_list,
3064 struct perf_event, event_entry);
3066 while (&event->event_entry != &ctx->event_list &&
3067 &next_event->event_entry != &next_ctx->event_list) {
3069 __perf_event_sync_stat(event, next_event);
3071 event = list_next_entry(event, event_entry);
3072 next_event = list_next_entry(next_event, event_entry);
3076 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3077 struct task_struct *next)
3079 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3080 struct perf_event_context *next_ctx;
3081 struct perf_event_context *parent, *next_parent;
3082 struct perf_cpu_context *cpuctx;
3088 cpuctx = __get_cpu_context(ctx);
3089 if (!cpuctx->task_ctx)
3093 next_ctx = next->perf_event_ctxp[ctxn];
3097 parent = rcu_dereference(ctx->parent_ctx);
3098 next_parent = rcu_dereference(next_ctx->parent_ctx);
3100 /* If neither context have a parent context; they cannot be clones. */
3101 if (!parent && !next_parent)
3104 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3106 * Looks like the two contexts are clones, so we might be
3107 * able to optimize the context switch. We lock both
3108 * contexts and check that they are clones under the
3109 * lock (including re-checking that neither has been
3110 * uncloned in the meantime). It doesn't matter which
3111 * order we take the locks because no other cpu could
3112 * be trying to lock both of these tasks.
3114 raw_spin_lock(&ctx->lock);
3115 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3116 if (context_equiv(ctx, next_ctx)) {
3117 WRITE_ONCE(ctx->task, next);
3118 WRITE_ONCE(next_ctx->task, task);
3120 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3123 * RCU_INIT_POINTER here is safe because we've not
3124 * modified the ctx and the above modification of
3125 * ctx->task and ctx->task_ctx_data are immaterial
3126 * since those values are always verified under
3127 * ctx->lock which we're now holding.
3129 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3130 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3134 perf_event_sync_stat(ctx, next_ctx);
3136 raw_spin_unlock(&next_ctx->lock);
3137 raw_spin_unlock(&ctx->lock);
3143 raw_spin_lock(&ctx->lock);
3144 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3145 raw_spin_unlock(&ctx->lock);
3149 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3151 void perf_sched_cb_dec(struct pmu *pmu)
3153 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3155 this_cpu_dec(perf_sched_cb_usages);
3157 if (!--cpuctx->sched_cb_usage)
3158 list_del(&cpuctx->sched_cb_entry);
3162 void perf_sched_cb_inc(struct pmu *pmu)
3164 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3166 if (!cpuctx->sched_cb_usage++)
3167 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3169 this_cpu_inc(perf_sched_cb_usages);
3173 * This function provides the context switch callback to the lower code
3174 * layer. It is invoked ONLY when the context switch callback is enabled.
3176 * This callback is relevant even to per-cpu events; for example multi event
3177 * PEBS requires this to provide PID/TID information. This requires we flush
3178 * all queued PEBS records before we context switch to a new task.
3180 static void perf_pmu_sched_task(struct task_struct *prev,
3181 struct task_struct *next,
3184 struct perf_cpu_context *cpuctx;
3190 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3191 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3193 if (WARN_ON_ONCE(!pmu->sched_task))
3196 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3197 perf_pmu_disable(pmu);
3199 pmu->sched_task(cpuctx->task_ctx, sched_in);
3201 perf_pmu_enable(pmu);
3202 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3206 static void perf_event_switch(struct task_struct *task,
3207 struct task_struct *next_prev, bool sched_in);
3209 #define for_each_task_context_nr(ctxn) \
3210 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3213 * Called from scheduler to remove the events of the current task,
3214 * with interrupts disabled.
3216 * We stop each event and update the event value in event->count.
3218 * This does not protect us against NMI, but disable()
3219 * sets the disabled bit in the control field of event _before_
3220 * accessing the event control register. If a NMI hits, then it will
3221 * not restart the event.
3223 void __perf_event_task_sched_out(struct task_struct *task,
3224 struct task_struct *next)
3228 if (__this_cpu_read(perf_sched_cb_usages))
3229 perf_pmu_sched_task(task, next, false);
3231 if (atomic_read(&nr_switch_events))
3232 perf_event_switch(task, next, false);
3234 for_each_task_context_nr(ctxn)
3235 perf_event_context_sched_out(task, ctxn, next);
3238 * if cgroup events exist on this CPU, then we need
3239 * to check if we have to switch out PMU state.
3240 * cgroup event are system-wide mode only
3242 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3243 perf_cgroup_sched_out(task, next);
3247 * Called with IRQs disabled
3249 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3250 enum event_type_t event_type)
3252 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3255 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3256 int (*func)(struct perf_event *, void *), void *data)
3258 struct perf_event **evt, *evt1, *evt2;
3261 evt1 = perf_event_groups_first(groups, -1);
3262 evt2 = perf_event_groups_first(groups, cpu);
3264 while (evt1 || evt2) {
3266 if (evt1->group_index < evt2->group_index)
3276 ret = func(*evt, data);
3280 *evt = perf_event_groups_next(*evt);
3286 struct sched_in_data {
3287 struct perf_event_context *ctx;
3288 struct perf_cpu_context *cpuctx;
3292 static int pinned_sched_in(struct perf_event *event, void *data)
3294 struct sched_in_data *sid = data;
3296 if (event->state <= PERF_EVENT_STATE_OFF)
3299 if (!event_filter_match(event))
3302 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3303 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3304 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3308 * If this pinned group hasn't been scheduled,
3309 * put it in error state.
3311 if (event->state == PERF_EVENT_STATE_INACTIVE)
3312 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3317 static int flexible_sched_in(struct perf_event *event, void *data)
3319 struct sched_in_data *sid = data;
3321 if (event->state <= PERF_EVENT_STATE_OFF)
3324 if (!event_filter_match(event))
3327 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3328 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3330 sid->can_add_hw = 0;
3331 sid->ctx->rotate_necessary = 1;
3334 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3341 ctx_pinned_sched_in(struct perf_event_context *ctx,
3342 struct perf_cpu_context *cpuctx)
3344 struct sched_in_data sid = {
3350 visit_groups_merge(&ctx->pinned_groups,
3352 pinned_sched_in, &sid);
3356 ctx_flexible_sched_in(struct perf_event_context *ctx,
3357 struct perf_cpu_context *cpuctx)
3359 struct sched_in_data sid = {
3365 visit_groups_merge(&ctx->flexible_groups,
3367 flexible_sched_in, &sid);
3371 ctx_sched_in(struct perf_event_context *ctx,
3372 struct perf_cpu_context *cpuctx,
3373 enum event_type_t event_type,
3374 struct task_struct *task)
3376 int is_active = ctx->is_active;
3379 lockdep_assert_held(&ctx->lock);
3381 if (likely(!ctx->nr_events))
3384 ctx->is_active |= (event_type | EVENT_TIME);
3387 cpuctx->task_ctx = ctx;
3389 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3392 is_active ^= ctx->is_active; /* changed bits */
3394 if (is_active & EVENT_TIME) {
3395 /* start ctx time */
3397 ctx->timestamp = now;
3398 perf_cgroup_set_timestamp(task, ctx);
3402 * First go through the list and put on any pinned groups
3403 * in order to give them the best chance of going on.
3405 if (is_active & EVENT_PINNED)
3406 ctx_pinned_sched_in(ctx, cpuctx);
3408 /* Then walk through the lower prio flexible groups */
3409 if (is_active & EVENT_FLEXIBLE)
3410 ctx_flexible_sched_in(ctx, cpuctx);
3413 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3414 enum event_type_t event_type,
3415 struct task_struct *task)
3417 struct perf_event_context *ctx = &cpuctx->ctx;
3419 ctx_sched_in(ctx, cpuctx, event_type, task);
3422 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3423 struct task_struct *task)
3425 struct perf_cpu_context *cpuctx;
3427 cpuctx = __get_cpu_context(ctx);
3428 if (cpuctx->task_ctx == ctx)
3431 perf_ctx_lock(cpuctx, ctx);
3433 * We must check ctx->nr_events while holding ctx->lock, such
3434 * that we serialize against perf_install_in_context().
3436 if (!ctx->nr_events)
3439 perf_pmu_disable(ctx->pmu);
3441 * We want to keep the following priority order:
3442 * cpu pinned (that don't need to move), task pinned,
3443 * cpu flexible, task flexible.
3445 * However, if task's ctx is not carrying any pinned
3446 * events, no need to flip the cpuctx's events around.
3448 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3449 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3450 perf_event_sched_in(cpuctx, ctx, task);
3451 perf_pmu_enable(ctx->pmu);
3454 perf_ctx_unlock(cpuctx, ctx);
3458 * Called from scheduler to add the events of the current task
3459 * with interrupts disabled.
3461 * We restore the event value and then enable it.
3463 * This does not protect us against NMI, but enable()
3464 * sets the enabled bit in the control field of event _before_
3465 * accessing the event control register. If a NMI hits, then it will
3466 * keep the event running.
3468 void __perf_event_task_sched_in(struct task_struct *prev,
3469 struct task_struct *task)
3471 struct perf_event_context *ctx;
3475 * If cgroup events exist on this CPU, then we need to check if we have
3476 * to switch in PMU state; cgroup event are system-wide mode only.
3478 * Since cgroup events are CPU events, we must schedule these in before
3479 * we schedule in the task events.
3481 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3482 perf_cgroup_sched_in(prev, task);
3484 for_each_task_context_nr(ctxn) {
3485 ctx = task->perf_event_ctxp[ctxn];
3489 perf_event_context_sched_in(ctx, task);
3492 if (atomic_read(&nr_switch_events))
3493 perf_event_switch(task, prev, true);
3495 if (__this_cpu_read(perf_sched_cb_usages))
3496 perf_pmu_sched_task(prev, task, true);
3499 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3501 u64 frequency = event->attr.sample_freq;
3502 u64 sec = NSEC_PER_SEC;
3503 u64 divisor, dividend;
3505 int count_fls, nsec_fls, frequency_fls, sec_fls;
3507 count_fls = fls64(count);
3508 nsec_fls = fls64(nsec);
3509 frequency_fls = fls64(frequency);
3513 * We got @count in @nsec, with a target of sample_freq HZ
3514 * the target period becomes:
3517 * period = -------------------
3518 * @nsec * sample_freq
3523 * Reduce accuracy by one bit such that @a and @b converge
3524 * to a similar magnitude.
3526 #define REDUCE_FLS(a, b) \
3528 if (a##_fls > b##_fls) { \
3538 * Reduce accuracy until either term fits in a u64, then proceed with
3539 * the other, so that finally we can do a u64/u64 division.
3541 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3542 REDUCE_FLS(nsec, frequency);
3543 REDUCE_FLS(sec, count);
3546 if (count_fls + sec_fls > 64) {
3547 divisor = nsec * frequency;
3549 while (count_fls + sec_fls > 64) {
3550 REDUCE_FLS(count, sec);
3554 dividend = count * sec;
3556 dividend = count * sec;
3558 while (nsec_fls + frequency_fls > 64) {
3559 REDUCE_FLS(nsec, frequency);
3563 divisor = nsec * frequency;
3569 return div64_u64(dividend, divisor);
3572 static DEFINE_PER_CPU(int, perf_throttled_count);
3573 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3575 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3577 struct hw_perf_event *hwc = &event->hw;
3578 s64 period, sample_period;
3581 period = perf_calculate_period(event, nsec, count);
3583 delta = (s64)(period - hwc->sample_period);
3584 delta = (delta + 7) / 8; /* low pass filter */
3586 sample_period = hwc->sample_period + delta;
3591 hwc->sample_period = sample_period;
3593 if (local64_read(&hwc->period_left) > 8*sample_period) {
3595 event->pmu->stop(event, PERF_EF_UPDATE);
3597 local64_set(&hwc->period_left, 0);
3600 event->pmu->start(event, PERF_EF_RELOAD);
3605 * combine freq adjustment with unthrottling to avoid two passes over the
3606 * events. At the same time, make sure, having freq events does not change
3607 * the rate of unthrottling as that would introduce bias.
3609 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3612 struct perf_event *event;
3613 struct hw_perf_event *hwc;
3614 u64 now, period = TICK_NSEC;
3618 * only need to iterate over all events iff:
3619 * - context have events in frequency mode (needs freq adjust)
3620 * - there are events to unthrottle on this cpu
3622 if (!(ctx->nr_freq || needs_unthr))
3625 raw_spin_lock(&ctx->lock);
3626 perf_pmu_disable(ctx->pmu);
3628 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3629 if (event->state != PERF_EVENT_STATE_ACTIVE)
3632 if (!event_filter_match(event))
3635 perf_pmu_disable(event->pmu);
3639 if (hwc->interrupts == MAX_INTERRUPTS) {
3640 hwc->interrupts = 0;
3641 perf_log_throttle(event, 1);
3642 event->pmu->start(event, 0);
3645 if (!event->attr.freq || !event->attr.sample_freq)
3649 * stop the event and update event->count
3651 event->pmu->stop(event, PERF_EF_UPDATE);
3653 now = local64_read(&event->count);
3654 delta = now - hwc->freq_count_stamp;
3655 hwc->freq_count_stamp = now;
3659 * reload only if value has changed
3660 * we have stopped the event so tell that
3661 * to perf_adjust_period() to avoid stopping it
3665 perf_adjust_period(event, period, delta, false);
3667 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3669 perf_pmu_enable(event->pmu);
3672 perf_pmu_enable(ctx->pmu);
3673 raw_spin_unlock(&ctx->lock);
3677 * Move @event to the tail of the @ctx's elegible events.
3679 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3682 * Rotate the first entry last of non-pinned groups. Rotation might be
3683 * disabled by the inheritance code.
3685 if (ctx->rotate_disable)
3688 perf_event_groups_delete(&ctx->flexible_groups, event);
3689 perf_event_groups_insert(&ctx->flexible_groups, event);
3692 static inline struct perf_event *
3693 ctx_first_active(struct perf_event_context *ctx)
3695 return list_first_entry_or_null(&ctx->flexible_active,
3696 struct perf_event, active_list);
3699 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3701 struct perf_event *cpu_event = NULL, *task_event = NULL;
3702 struct perf_event_context *task_ctx = NULL;
3703 int cpu_rotate, task_rotate;
3706 * Since we run this from IRQ context, nobody can install new
3707 * events, thus the event count values are stable.
3710 cpu_rotate = cpuctx->ctx.rotate_necessary;
3711 task_ctx = cpuctx->task_ctx;
3712 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3714 if (!(cpu_rotate || task_rotate))
3717 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3718 perf_pmu_disable(cpuctx->ctx.pmu);
3721 task_event = ctx_first_active(task_ctx);
3723 cpu_event = ctx_first_active(&cpuctx->ctx);
3726 * As per the order given at ctx_resched() first 'pop' task flexible
3727 * and then, if needed CPU flexible.
3729 if (task_event || (task_ctx && cpu_event))
3730 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3732 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3735 rotate_ctx(task_ctx, task_event);
3737 rotate_ctx(&cpuctx->ctx, cpu_event);
3739 perf_event_sched_in(cpuctx, task_ctx, current);
3741 perf_pmu_enable(cpuctx->ctx.pmu);
3742 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3747 void perf_event_task_tick(void)
3749 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3750 struct perf_event_context *ctx, *tmp;
3753 lockdep_assert_irqs_disabled();
3755 __this_cpu_inc(perf_throttled_seq);
3756 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3757 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3759 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3760 perf_adjust_freq_unthr_context(ctx, throttled);
3763 static int event_enable_on_exec(struct perf_event *event,
3764 struct perf_event_context *ctx)
3766 if (!event->attr.enable_on_exec)
3769 event->attr.enable_on_exec = 0;
3770 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3773 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3779 * Enable all of a task's events that have been marked enable-on-exec.
3780 * This expects task == current.
3782 static void perf_event_enable_on_exec(int ctxn)
3784 struct perf_event_context *ctx, *clone_ctx = NULL;
3785 enum event_type_t event_type = 0;
3786 struct perf_cpu_context *cpuctx;
3787 struct perf_event *event;
3788 unsigned long flags;
3791 local_irq_save(flags);
3792 ctx = current->perf_event_ctxp[ctxn];
3793 if (!ctx || !ctx->nr_events)
3796 cpuctx = __get_cpu_context(ctx);
3797 perf_ctx_lock(cpuctx, ctx);
3798 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3799 list_for_each_entry(event, &ctx->event_list, event_entry) {
3800 enabled |= event_enable_on_exec(event, ctx);
3801 event_type |= get_event_type(event);
3805 * Unclone and reschedule this context if we enabled any event.
3808 clone_ctx = unclone_ctx(ctx);
3809 ctx_resched(cpuctx, ctx, event_type);
3811 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3813 perf_ctx_unlock(cpuctx, ctx);
3816 local_irq_restore(flags);
3822 struct perf_read_data {
3823 struct perf_event *event;
3828 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3830 u16 local_pkg, event_pkg;
3832 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3833 int local_cpu = smp_processor_id();
3835 event_pkg = topology_physical_package_id(event_cpu);
3836 local_pkg = topology_physical_package_id(local_cpu);
3838 if (event_pkg == local_pkg)
3846 * Cross CPU call to read the hardware event
3848 static void __perf_event_read(void *info)
3850 struct perf_read_data *data = info;
3851 struct perf_event *sub, *event = data->event;
3852 struct perf_event_context *ctx = event->ctx;
3853 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3854 struct pmu *pmu = event->pmu;
3857 * If this is a task context, we need to check whether it is
3858 * the current task context of this cpu. If not it has been
3859 * scheduled out before the smp call arrived. In that case
3860 * event->count would have been updated to a recent sample
3861 * when the event was scheduled out.
3863 if (ctx->task && cpuctx->task_ctx != ctx)
3866 raw_spin_lock(&ctx->lock);
3867 if (ctx->is_active & EVENT_TIME) {
3868 update_context_time(ctx);
3869 update_cgrp_time_from_event(event);
3872 perf_event_update_time(event);
3874 perf_event_update_sibling_time(event);
3876 if (event->state != PERF_EVENT_STATE_ACTIVE)
3885 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3889 for_each_sibling_event(sub, event) {
3890 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3892 * Use sibling's PMU rather than @event's since
3893 * sibling could be on different (eg: software) PMU.
3895 sub->pmu->read(sub);
3899 data->ret = pmu->commit_txn(pmu);
3902 raw_spin_unlock(&ctx->lock);
3905 static inline u64 perf_event_count(struct perf_event *event)
3907 return local64_read(&event->count) + atomic64_read(&event->child_count);
3911 * NMI-safe method to read a local event, that is an event that
3913 * - either for the current task, or for this CPU
3914 * - does not have inherit set, for inherited task events
3915 * will not be local and we cannot read them atomically
3916 * - must not have a pmu::count method
3918 int perf_event_read_local(struct perf_event *event, u64 *value,
3919 u64 *enabled, u64 *running)
3921 unsigned long flags;
3925 * Disabling interrupts avoids all counter scheduling (context
3926 * switches, timer based rotation and IPIs).
3928 local_irq_save(flags);
3931 * It must not be an event with inherit set, we cannot read
3932 * all child counters from atomic context.
3934 if (event->attr.inherit) {
3939 /* If this is a per-task event, it must be for current */
3940 if ((event->attach_state & PERF_ATTACH_TASK) &&
3941 event->hw.target != current) {
3946 /* If this is a per-CPU event, it must be for this CPU */
3947 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3948 event->cpu != smp_processor_id()) {
3953 /* If this is a pinned event it must be running on this CPU */
3954 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3960 * If the event is currently on this CPU, its either a per-task event,
3961 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3964 if (event->oncpu == smp_processor_id())
3965 event->pmu->read(event);
3967 *value = local64_read(&event->count);
3968 if (enabled || running) {
3969 u64 now = event->shadow_ctx_time + perf_clock();
3970 u64 __enabled, __running;
3972 __perf_update_times(event, now, &__enabled, &__running);
3974 *enabled = __enabled;
3976 *running = __running;
3979 local_irq_restore(flags);
3984 static int perf_event_read(struct perf_event *event, bool group)
3986 enum perf_event_state state = READ_ONCE(event->state);
3987 int event_cpu, ret = 0;
3990 * If event is enabled and currently active on a CPU, update the
3991 * value in the event structure:
3994 if (state == PERF_EVENT_STATE_ACTIVE) {
3995 struct perf_read_data data;
3998 * Orders the ->state and ->oncpu loads such that if we see
3999 * ACTIVE we must also see the right ->oncpu.
4001 * Matches the smp_wmb() from event_sched_in().
4005 event_cpu = READ_ONCE(event->oncpu);
4006 if ((unsigned)event_cpu >= nr_cpu_ids)
4009 data = (struct perf_read_data){
4016 event_cpu = __perf_event_read_cpu(event, event_cpu);
4019 * Purposely ignore the smp_call_function_single() return
4022 * If event_cpu isn't a valid CPU it means the event got
4023 * scheduled out and that will have updated the event count.
4025 * Therefore, either way, we'll have an up-to-date event count
4028 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4032 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4033 struct perf_event_context *ctx = event->ctx;
4034 unsigned long flags;
4036 raw_spin_lock_irqsave(&ctx->lock, flags);
4037 state = event->state;
4038 if (state != PERF_EVENT_STATE_INACTIVE) {
4039 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4044 * May read while context is not active (e.g., thread is
4045 * blocked), in that case we cannot update context time
4047 if (ctx->is_active & EVENT_TIME) {
4048 update_context_time(ctx);
4049 update_cgrp_time_from_event(event);
4052 perf_event_update_time(event);
4054 perf_event_update_sibling_time(event);
4055 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4062 * Initialize the perf_event context in a task_struct:
4064 static void __perf_event_init_context(struct perf_event_context *ctx)
4066 raw_spin_lock_init(&ctx->lock);
4067 mutex_init(&ctx->mutex);
4068 INIT_LIST_HEAD(&ctx->active_ctx_list);
4069 perf_event_groups_init(&ctx->pinned_groups);
4070 perf_event_groups_init(&ctx->flexible_groups);
4071 INIT_LIST_HEAD(&ctx->event_list);
4072 INIT_LIST_HEAD(&ctx->pinned_active);
4073 INIT_LIST_HEAD(&ctx->flexible_active);
4074 refcount_set(&ctx->refcount, 1);
4077 static struct perf_event_context *
4078 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4080 struct perf_event_context *ctx;
4082 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4086 __perf_event_init_context(ctx);
4089 get_task_struct(task);
4096 static struct task_struct *
4097 find_lively_task_by_vpid(pid_t vpid)
4099 struct task_struct *task;
4105 task = find_task_by_vpid(vpid);
4107 get_task_struct(task);
4111 return ERR_PTR(-ESRCH);
4117 * Returns a matching context with refcount and pincount.
4119 static struct perf_event_context *
4120 find_get_context(struct pmu *pmu, struct task_struct *task,
4121 struct perf_event *event)
4123 struct perf_event_context *ctx, *clone_ctx = NULL;
4124 struct perf_cpu_context *cpuctx;
4125 void *task_ctx_data = NULL;
4126 unsigned long flags;
4128 int cpu = event->cpu;
4131 /* Must be root to operate on a CPU event: */
4132 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4133 return ERR_PTR(-EACCES);
4135 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4144 ctxn = pmu->task_ctx_nr;
4148 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4149 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4150 if (!task_ctx_data) {
4157 ctx = perf_lock_task_context(task, ctxn, &flags);
4159 clone_ctx = unclone_ctx(ctx);
4162 if (task_ctx_data && !ctx->task_ctx_data) {
4163 ctx->task_ctx_data = task_ctx_data;
4164 task_ctx_data = NULL;
4166 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4171 ctx = alloc_perf_context(pmu, task);
4176 if (task_ctx_data) {
4177 ctx->task_ctx_data = task_ctx_data;
4178 task_ctx_data = NULL;
4182 mutex_lock(&task->perf_event_mutex);
4184 * If it has already passed perf_event_exit_task().
4185 * we must see PF_EXITING, it takes this mutex too.
4187 if (task->flags & PF_EXITING)
4189 else if (task->perf_event_ctxp[ctxn])
4194 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4196 mutex_unlock(&task->perf_event_mutex);
4198 if (unlikely(err)) {
4207 kfree(task_ctx_data);
4211 kfree(task_ctx_data);
4212 return ERR_PTR(err);
4215 static void perf_event_free_filter(struct perf_event *event);
4216 static void perf_event_free_bpf_prog(struct perf_event *event);
4218 static void free_event_rcu(struct rcu_head *head)
4220 struct perf_event *event;
4222 event = container_of(head, struct perf_event, rcu_head);
4224 put_pid_ns(event->ns);
4225 perf_event_free_filter(event);
4229 static void ring_buffer_attach(struct perf_event *event,
4230 struct ring_buffer *rb);
4232 static void detach_sb_event(struct perf_event *event)
4234 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4236 raw_spin_lock(&pel->lock);
4237 list_del_rcu(&event->sb_list);
4238 raw_spin_unlock(&pel->lock);
4241 static bool is_sb_event(struct perf_event *event)
4243 struct perf_event_attr *attr = &event->attr;
4248 if (event->attach_state & PERF_ATTACH_TASK)
4251 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4252 attr->comm || attr->comm_exec ||
4253 attr->task || attr->ksymbol ||
4254 attr->context_switch ||
4260 static void unaccount_pmu_sb_event(struct perf_event *event)
4262 if (is_sb_event(event))
4263 detach_sb_event(event);
4266 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4271 if (is_cgroup_event(event))
4272 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4275 #ifdef CONFIG_NO_HZ_FULL
4276 static DEFINE_SPINLOCK(nr_freq_lock);
4279 static void unaccount_freq_event_nohz(void)
4281 #ifdef CONFIG_NO_HZ_FULL
4282 spin_lock(&nr_freq_lock);
4283 if (atomic_dec_and_test(&nr_freq_events))
4284 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4285 spin_unlock(&nr_freq_lock);
4289 static void unaccount_freq_event(void)
4291 if (tick_nohz_full_enabled())
4292 unaccount_freq_event_nohz();
4294 atomic_dec(&nr_freq_events);
4297 static void unaccount_event(struct perf_event *event)
4304 if (event->attach_state & PERF_ATTACH_TASK)
4306 if (event->attr.mmap || event->attr.mmap_data)
4307 atomic_dec(&nr_mmap_events);
4308 if (event->attr.comm)
4309 atomic_dec(&nr_comm_events);
4310 if (event->attr.namespaces)
4311 atomic_dec(&nr_namespaces_events);
4312 if (event->attr.task)
4313 atomic_dec(&nr_task_events);
4314 if (event->attr.freq)
4315 unaccount_freq_event();
4316 if (event->attr.context_switch) {
4318 atomic_dec(&nr_switch_events);
4320 if (is_cgroup_event(event))
4322 if (has_branch_stack(event))
4324 if (event->attr.ksymbol)
4325 atomic_dec(&nr_ksymbol_events);
4326 if (event->attr.bpf_event)
4327 atomic_dec(&nr_bpf_events);
4330 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4331 schedule_delayed_work(&perf_sched_work, HZ);
4334 unaccount_event_cpu(event, event->cpu);
4336 unaccount_pmu_sb_event(event);
4339 static void perf_sched_delayed(struct work_struct *work)
4341 mutex_lock(&perf_sched_mutex);
4342 if (atomic_dec_and_test(&perf_sched_count))
4343 static_branch_disable(&perf_sched_events);
4344 mutex_unlock(&perf_sched_mutex);
4348 * The following implement mutual exclusion of events on "exclusive" pmus
4349 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4350 * at a time, so we disallow creating events that might conflict, namely:
4352 * 1) cpu-wide events in the presence of per-task events,
4353 * 2) per-task events in the presence of cpu-wide events,
4354 * 3) two matching events on the same context.
4356 * The former two cases are handled in the allocation path (perf_event_alloc(),
4357 * _free_event()), the latter -- before the first perf_install_in_context().
4359 static int exclusive_event_init(struct perf_event *event)
4361 struct pmu *pmu = event->pmu;
4363 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4367 * Prevent co-existence of per-task and cpu-wide events on the
4368 * same exclusive pmu.
4370 * Negative pmu::exclusive_cnt means there are cpu-wide
4371 * events on this "exclusive" pmu, positive means there are
4374 * Since this is called in perf_event_alloc() path, event::ctx
4375 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4376 * to mean "per-task event", because unlike other attach states it
4377 * never gets cleared.
4379 if (event->attach_state & PERF_ATTACH_TASK) {
4380 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4383 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4390 static void exclusive_event_destroy(struct perf_event *event)
4392 struct pmu *pmu = event->pmu;
4394 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4397 /* see comment in exclusive_event_init() */
4398 if (event->attach_state & PERF_ATTACH_TASK)
4399 atomic_dec(&pmu->exclusive_cnt);
4401 atomic_inc(&pmu->exclusive_cnt);
4404 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4406 if ((e1->pmu == e2->pmu) &&
4407 (e1->cpu == e2->cpu ||
4414 /* Called under the same ctx::mutex as perf_install_in_context() */
4415 static bool exclusive_event_installable(struct perf_event *event,
4416 struct perf_event_context *ctx)
4418 struct perf_event *iter_event;
4419 struct pmu *pmu = event->pmu;
4421 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4424 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4425 if (exclusive_event_match(iter_event, event))
4432 static void perf_addr_filters_splice(struct perf_event *event,
4433 struct list_head *head);
4435 static void _free_event(struct perf_event *event)
4437 irq_work_sync(&event->pending);
4439 unaccount_event(event);
4443 * Can happen when we close an event with re-directed output.
4445 * Since we have a 0 refcount, perf_mmap_close() will skip
4446 * over us; possibly making our ring_buffer_put() the last.
4448 mutex_lock(&event->mmap_mutex);
4449 ring_buffer_attach(event, NULL);
4450 mutex_unlock(&event->mmap_mutex);
4453 if (is_cgroup_event(event))
4454 perf_detach_cgroup(event);
4456 if (!event->parent) {
4457 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4458 put_callchain_buffers();
4461 perf_event_free_bpf_prog(event);
4462 perf_addr_filters_splice(event, NULL);
4463 kfree(event->addr_filter_ranges);
4466 event->destroy(event);
4469 put_ctx(event->ctx);
4471 if (event->hw.target)
4472 put_task_struct(event->hw.target);
4474 exclusive_event_destroy(event);
4475 module_put(event->pmu->module);
4477 call_rcu(&event->rcu_head, free_event_rcu);
4481 * Used to free events which have a known refcount of 1, such as in error paths
4482 * where the event isn't exposed yet and inherited events.
4484 static void free_event(struct perf_event *event)
4486 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4487 "unexpected event refcount: %ld; ptr=%p\n",
4488 atomic_long_read(&event->refcount), event)) {
4489 /* leak to avoid use-after-free */
4497 * Remove user event from the owner task.
4499 static void perf_remove_from_owner(struct perf_event *event)
4501 struct task_struct *owner;
4505 * Matches the smp_store_release() in perf_event_exit_task(). If we
4506 * observe !owner it means the list deletion is complete and we can
4507 * indeed free this event, otherwise we need to serialize on
4508 * owner->perf_event_mutex.
4510 owner = READ_ONCE(event->owner);
4513 * Since delayed_put_task_struct() also drops the last
4514 * task reference we can safely take a new reference
4515 * while holding the rcu_read_lock().
4517 get_task_struct(owner);
4523 * If we're here through perf_event_exit_task() we're already
4524 * holding ctx->mutex which would be an inversion wrt. the
4525 * normal lock order.
4527 * However we can safely take this lock because its the child
4530 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4533 * We have to re-check the event->owner field, if it is cleared
4534 * we raced with perf_event_exit_task(), acquiring the mutex
4535 * ensured they're done, and we can proceed with freeing the
4539 list_del_init(&event->owner_entry);
4540 smp_store_release(&event->owner, NULL);
4542 mutex_unlock(&owner->perf_event_mutex);
4543 put_task_struct(owner);
4547 static void put_event(struct perf_event *event)
4549 if (!atomic_long_dec_and_test(&event->refcount))
4556 * Kill an event dead; while event:refcount will preserve the event
4557 * object, it will not preserve its functionality. Once the last 'user'
4558 * gives up the object, we'll destroy the thing.
4560 int perf_event_release_kernel(struct perf_event *event)
4562 struct perf_event_context *ctx = event->ctx;
4563 struct perf_event *child, *tmp;
4564 LIST_HEAD(free_list);
4567 * If we got here through err_file: fput(event_file); we will not have
4568 * attached to a context yet.
4571 WARN_ON_ONCE(event->attach_state &
4572 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4576 if (!is_kernel_event(event))
4577 perf_remove_from_owner(event);
4579 ctx = perf_event_ctx_lock(event);
4580 WARN_ON_ONCE(ctx->parent_ctx);
4581 perf_remove_from_context(event, DETACH_GROUP);
4583 raw_spin_lock_irq(&ctx->lock);
4585 * Mark this event as STATE_DEAD, there is no external reference to it
4588 * Anybody acquiring event->child_mutex after the below loop _must_
4589 * also see this, most importantly inherit_event() which will avoid
4590 * placing more children on the list.
4592 * Thus this guarantees that we will in fact observe and kill _ALL_
4595 event->state = PERF_EVENT_STATE_DEAD;
4596 raw_spin_unlock_irq(&ctx->lock);
4598 perf_event_ctx_unlock(event, ctx);
4601 mutex_lock(&event->child_mutex);
4602 list_for_each_entry(child, &event->child_list, child_list) {
4605 * Cannot change, child events are not migrated, see the
4606 * comment with perf_event_ctx_lock_nested().
4608 ctx = READ_ONCE(child->ctx);
4610 * Since child_mutex nests inside ctx::mutex, we must jump
4611 * through hoops. We start by grabbing a reference on the ctx.
4613 * Since the event cannot get freed while we hold the
4614 * child_mutex, the context must also exist and have a !0
4620 * Now that we have a ctx ref, we can drop child_mutex, and
4621 * acquire ctx::mutex without fear of it going away. Then we
4622 * can re-acquire child_mutex.
4624 mutex_unlock(&event->child_mutex);
4625 mutex_lock(&ctx->mutex);
4626 mutex_lock(&event->child_mutex);
4629 * Now that we hold ctx::mutex and child_mutex, revalidate our
4630 * state, if child is still the first entry, it didn't get freed
4631 * and we can continue doing so.
4633 tmp = list_first_entry_or_null(&event->child_list,
4634 struct perf_event, child_list);
4636 perf_remove_from_context(child, DETACH_GROUP);
4637 list_move(&child->child_list, &free_list);
4639 * This matches the refcount bump in inherit_event();
4640 * this can't be the last reference.
4645 mutex_unlock(&event->child_mutex);
4646 mutex_unlock(&ctx->mutex);
4650 mutex_unlock(&event->child_mutex);
4652 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4653 list_del(&child->child_list);
4658 put_event(event); /* Must be the 'last' reference */
4661 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4664 * Called when the last reference to the file is gone.
4666 static int perf_release(struct inode *inode, struct file *file)
4668 perf_event_release_kernel(file->private_data);
4672 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4674 struct perf_event *child;
4680 mutex_lock(&event->child_mutex);
4682 (void)perf_event_read(event, false);
4683 total += perf_event_count(event);
4685 *enabled += event->total_time_enabled +
4686 atomic64_read(&event->child_total_time_enabled);
4687 *running += event->total_time_running +
4688 atomic64_read(&event->child_total_time_running);
4690 list_for_each_entry(child, &event->child_list, child_list) {
4691 (void)perf_event_read(child, false);
4692 total += perf_event_count(child);
4693 *enabled += child->total_time_enabled;
4694 *running += child->total_time_running;
4696 mutex_unlock(&event->child_mutex);
4701 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4703 struct perf_event_context *ctx;
4706 ctx = perf_event_ctx_lock(event);
4707 count = __perf_event_read_value(event, enabled, running);
4708 perf_event_ctx_unlock(event, ctx);
4712 EXPORT_SYMBOL_GPL(perf_event_read_value);
4714 static int __perf_read_group_add(struct perf_event *leader,
4715 u64 read_format, u64 *values)
4717 struct perf_event_context *ctx = leader->ctx;
4718 struct perf_event *sub;
4719 unsigned long flags;
4720 int n = 1; /* skip @nr */
4723 ret = perf_event_read(leader, true);
4727 raw_spin_lock_irqsave(&ctx->lock, flags);
4730 * Since we co-schedule groups, {enabled,running} times of siblings
4731 * will be identical to those of the leader, so we only publish one
4734 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4735 values[n++] += leader->total_time_enabled +
4736 atomic64_read(&leader->child_total_time_enabled);
4739 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4740 values[n++] += leader->total_time_running +
4741 atomic64_read(&leader->child_total_time_running);
4745 * Write {count,id} tuples for every sibling.
4747 values[n++] += perf_event_count(leader);
4748 if (read_format & PERF_FORMAT_ID)
4749 values[n++] = primary_event_id(leader);
4751 for_each_sibling_event(sub, leader) {
4752 values[n++] += perf_event_count(sub);
4753 if (read_format & PERF_FORMAT_ID)
4754 values[n++] = primary_event_id(sub);
4757 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4761 static int perf_read_group(struct perf_event *event,
4762 u64 read_format, char __user *buf)
4764 struct perf_event *leader = event->group_leader, *child;
4765 struct perf_event_context *ctx = leader->ctx;
4769 lockdep_assert_held(&ctx->mutex);
4771 values = kzalloc(event->read_size, GFP_KERNEL);
4775 values[0] = 1 + leader->nr_siblings;
4778 * By locking the child_mutex of the leader we effectively
4779 * lock the child list of all siblings.. XXX explain how.
4781 mutex_lock(&leader->child_mutex);
4783 ret = __perf_read_group_add(leader, read_format, values);
4787 list_for_each_entry(child, &leader->child_list, child_list) {
4788 ret = __perf_read_group_add(child, read_format, values);
4793 mutex_unlock(&leader->child_mutex);
4795 ret = event->read_size;
4796 if (copy_to_user(buf, values, event->read_size))
4801 mutex_unlock(&leader->child_mutex);
4807 static int perf_read_one(struct perf_event *event,
4808 u64 read_format, char __user *buf)
4810 u64 enabled, running;
4814 values[n++] = __perf_event_read_value(event, &enabled, &running);
4815 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4816 values[n++] = enabled;
4817 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4818 values[n++] = running;
4819 if (read_format & PERF_FORMAT_ID)
4820 values[n++] = primary_event_id(event);
4822 if (copy_to_user(buf, values, n * sizeof(u64)))
4825 return n * sizeof(u64);
4828 static bool is_event_hup(struct perf_event *event)
4832 if (event->state > PERF_EVENT_STATE_EXIT)
4835 mutex_lock(&event->child_mutex);
4836 no_children = list_empty(&event->child_list);
4837 mutex_unlock(&event->child_mutex);
4842 * Read the performance event - simple non blocking version for now
4845 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4847 u64 read_format = event->attr.read_format;
4851 * Return end-of-file for a read on an event that is in
4852 * error state (i.e. because it was pinned but it couldn't be
4853 * scheduled on to the CPU at some point).
4855 if (event->state == PERF_EVENT_STATE_ERROR)
4858 if (count < event->read_size)
4861 WARN_ON_ONCE(event->ctx->parent_ctx);
4862 if (read_format & PERF_FORMAT_GROUP)
4863 ret = perf_read_group(event, read_format, buf);
4865 ret = perf_read_one(event, read_format, buf);
4871 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4873 struct perf_event *event = file->private_data;
4874 struct perf_event_context *ctx;
4877 ctx = perf_event_ctx_lock(event);
4878 ret = __perf_read(event, buf, count);
4879 perf_event_ctx_unlock(event, ctx);
4884 static __poll_t perf_poll(struct file *file, poll_table *wait)
4886 struct perf_event *event = file->private_data;
4887 struct ring_buffer *rb;
4888 __poll_t events = EPOLLHUP;
4890 poll_wait(file, &event->waitq, wait);
4892 if (is_event_hup(event))
4896 * Pin the event->rb by taking event->mmap_mutex; otherwise
4897 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4899 mutex_lock(&event->mmap_mutex);
4902 events = atomic_xchg(&rb->poll, 0);
4903 mutex_unlock(&event->mmap_mutex);
4907 static void _perf_event_reset(struct perf_event *event)
4909 (void)perf_event_read(event, false);
4910 local64_set(&event->count, 0);
4911 perf_event_update_userpage(event);
4915 * Holding the top-level event's child_mutex means that any
4916 * descendant process that has inherited this event will block
4917 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4918 * task existence requirements of perf_event_enable/disable.
4920 static void perf_event_for_each_child(struct perf_event *event,
4921 void (*func)(struct perf_event *))
4923 struct perf_event *child;
4925 WARN_ON_ONCE(event->ctx->parent_ctx);
4927 mutex_lock(&event->child_mutex);
4929 list_for_each_entry(child, &event->child_list, child_list)
4931 mutex_unlock(&event->child_mutex);
4934 static void perf_event_for_each(struct perf_event *event,
4935 void (*func)(struct perf_event *))
4937 struct perf_event_context *ctx = event->ctx;
4938 struct perf_event *sibling;
4940 lockdep_assert_held(&ctx->mutex);
4942 event = event->group_leader;
4944 perf_event_for_each_child(event, func);
4945 for_each_sibling_event(sibling, event)
4946 perf_event_for_each_child(sibling, func);
4949 static void __perf_event_period(struct perf_event *event,
4950 struct perf_cpu_context *cpuctx,
4951 struct perf_event_context *ctx,
4954 u64 value = *((u64 *)info);
4957 if (event->attr.freq) {
4958 event->attr.sample_freq = value;
4960 event->attr.sample_period = value;
4961 event->hw.sample_period = value;
4964 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4966 perf_pmu_disable(ctx->pmu);
4968 * We could be throttled; unthrottle now to avoid the tick
4969 * trying to unthrottle while we already re-started the event.
4971 if (event->hw.interrupts == MAX_INTERRUPTS) {
4972 event->hw.interrupts = 0;
4973 perf_log_throttle(event, 1);
4975 event->pmu->stop(event, PERF_EF_UPDATE);
4978 local64_set(&event->hw.period_left, 0);
4981 event->pmu->start(event, PERF_EF_RELOAD);
4982 perf_pmu_enable(ctx->pmu);
4986 static int perf_event_check_period(struct perf_event *event, u64 value)
4988 return event->pmu->check_period(event, value);
4991 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4995 if (!is_sampling_event(event))
4998 if (copy_from_user(&value, arg, sizeof(value)))
5004 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5007 if (perf_event_check_period(event, value))
5010 if (!event->attr.freq && (value & (1ULL << 63)))
5013 event_function_call(event, __perf_event_period, &value);
5018 static const struct file_operations perf_fops;
5020 static inline int perf_fget_light(int fd, struct fd *p)
5022 struct fd f = fdget(fd);
5026 if (f.file->f_op != &perf_fops) {
5034 static int perf_event_set_output(struct perf_event *event,
5035 struct perf_event *output_event);
5036 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5037 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5038 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5039 struct perf_event_attr *attr);
5041 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5043 void (*func)(struct perf_event *);
5047 case PERF_EVENT_IOC_ENABLE:
5048 func = _perf_event_enable;
5050 case PERF_EVENT_IOC_DISABLE:
5051 func = _perf_event_disable;
5053 case PERF_EVENT_IOC_RESET:
5054 func = _perf_event_reset;
5057 case PERF_EVENT_IOC_REFRESH:
5058 return _perf_event_refresh(event, arg);
5060 case PERF_EVENT_IOC_PERIOD:
5061 return perf_event_period(event, (u64 __user *)arg);
5063 case PERF_EVENT_IOC_ID:
5065 u64 id = primary_event_id(event);
5067 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5072 case PERF_EVENT_IOC_SET_OUTPUT:
5076 struct perf_event *output_event;
5078 ret = perf_fget_light(arg, &output);
5081 output_event = output.file->private_data;
5082 ret = perf_event_set_output(event, output_event);
5085 ret = perf_event_set_output(event, NULL);
5090 case PERF_EVENT_IOC_SET_FILTER:
5091 return perf_event_set_filter(event, (void __user *)arg);
5093 case PERF_EVENT_IOC_SET_BPF:
5094 return perf_event_set_bpf_prog(event, arg);
5096 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5097 struct ring_buffer *rb;
5100 rb = rcu_dereference(event->rb);
5101 if (!rb || !rb->nr_pages) {
5105 rb_toggle_paused(rb, !!arg);
5110 case PERF_EVENT_IOC_QUERY_BPF:
5111 return perf_event_query_prog_array(event, (void __user *)arg);
5113 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5114 struct perf_event_attr new_attr;
5115 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5121 return perf_event_modify_attr(event, &new_attr);
5127 if (flags & PERF_IOC_FLAG_GROUP)
5128 perf_event_for_each(event, func);
5130 perf_event_for_each_child(event, func);
5135 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5137 struct perf_event *event = file->private_data;
5138 struct perf_event_context *ctx;
5141 ctx = perf_event_ctx_lock(event);
5142 ret = _perf_ioctl(event, cmd, arg);
5143 perf_event_ctx_unlock(event, ctx);
5148 #ifdef CONFIG_COMPAT
5149 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5152 switch (_IOC_NR(cmd)) {
5153 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5154 case _IOC_NR(PERF_EVENT_IOC_ID):
5155 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5156 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5157 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5158 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5159 cmd &= ~IOCSIZE_MASK;
5160 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5164 return perf_ioctl(file, cmd, arg);
5167 # define perf_compat_ioctl NULL
5170 int perf_event_task_enable(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_enable);
5179 perf_event_ctx_unlock(event, ctx);
5181 mutex_unlock(¤t->perf_event_mutex);
5186 int perf_event_task_disable(void)
5188 struct perf_event_context *ctx;
5189 struct perf_event *event;
5191 mutex_lock(¤t->perf_event_mutex);
5192 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5193 ctx = perf_event_ctx_lock(event);
5194 perf_event_for_each_child(event, _perf_event_disable);
5195 perf_event_ctx_unlock(event, ctx);
5197 mutex_unlock(¤t->perf_event_mutex);
5202 static int perf_event_index(struct perf_event *event)
5204 if (event->hw.state & PERF_HES_STOPPED)
5207 if (event->state != PERF_EVENT_STATE_ACTIVE)
5210 return event->pmu->event_idx(event);
5213 static void calc_timer_values(struct perf_event *event,
5220 *now = perf_clock();
5221 ctx_time = event->shadow_ctx_time + *now;
5222 __perf_update_times(event, ctx_time, enabled, running);
5225 static void perf_event_init_userpage(struct perf_event *event)
5227 struct perf_event_mmap_page *userpg;
5228 struct ring_buffer *rb;
5231 rb = rcu_dereference(event->rb);
5235 userpg = rb->user_page;
5237 /* Allow new userspace to detect that bit 0 is deprecated */
5238 userpg->cap_bit0_is_deprecated = 1;
5239 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5240 userpg->data_offset = PAGE_SIZE;
5241 userpg->data_size = perf_data_size(rb);
5247 void __weak arch_perf_update_userpage(
5248 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5253 * Callers need to ensure there can be no nesting of this function, otherwise
5254 * the seqlock logic goes bad. We can not serialize this because the arch
5255 * code calls this from NMI context.
5257 void perf_event_update_userpage(struct perf_event *event)
5259 struct perf_event_mmap_page *userpg;
5260 struct ring_buffer *rb;
5261 u64 enabled, running, now;
5264 rb = rcu_dereference(event->rb);
5269 * compute total_time_enabled, total_time_running
5270 * based on snapshot values taken when the event
5271 * was last scheduled in.
5273 * we cannot simply called update_context_time()
5274 * because of locking issue as we can be called in
5277 calc_timer_values(event, &now, &enabled, &running);
5279 userpg = rb->user_page;
5281 * Disable preemption to guarantee consistent time stamps are stored to
5287 userpg->index = perf_event_index(event);
5288 userpg->offset = perf_event_count(event);
5290 userpg->offset -= local64_read(&event->hw.prev_count);
5292 userpg->time_enabled = enabled +
5293 atomic64_read(&event->child_total_time_enabled);
5295 userpg->time_running = running +
5296 atomic64_read(&event->child_total_time_running);
5298 arch_perf_update_userpage(event, userpg, now);
5306 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5308 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5310 struct perf_event *event = vmf->vma->vm_file->private_data;
5311 struct ring_buffer *rb;
5312 vm_fault_t ret = VM_FAULT_SIGBUS;
5314 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5315 if (vmf->pgoff == 0)
5321 rb = rcu_dereference(event->rb);
5325 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5328 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5332 get_page(vmf->page);
5333 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5334 vmf->page->index = vmf->pgoff;
5343 static void ring_buffer_attach(struct perf_event *event,
5344 struct ring_buffer *rb)
5346 struct ring_buffer *old_rb = NULL;
5347 unsigned long flags;
5351 * Should be impossible, we set this when removing
5352 * event->rb_entry and wait/clear when adding event->rb_entry.
5354 WARN_ON_ONCE(event->rcu_pending);
5357 spin_lock_irqsave(&old_rb->event_lock, flags);
5358 list_del_rcu(&event->rb_entry);
5359 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5361 event->rcu_batches = get_state_synchronize_rcu();
5362 event->rcu_pending = 1;
5366 if (event->rcu_pending) {
5367 cond_synchronize_rcu(event->rcu_batches);
5368 event->rcu_pending = 0;
5371 spin_lock_irqsave(&rb->event_lock, flags);
5372 list_add_rcu(&event->rb_entry, &rb->event_list);
5373 spin_unlock_irqrestore(&rb->event_lock, flags);
5377 * Avoid racing with perf_mmap_close(AUX): stop the event
5378 * before swizzling the event::rb pointer; if it's getting
5379 * unmapped, its aux_mmap_count will be 0 and it won't
5380 * restart. See the comment in __perf_pmu_output_stop().
5382 * Data will inevitably be lost when set_output is done in
5383 * mid-air, but then again, whoever does it like this is
5384 * not in for the data anyway.
5387 perf_event_stop(event, 0);
5389 rcu_assign_pointer(event->rb, rb);
5392 ring_buffer_put(old_rb);
5394 * Since we detached before setting the new rb, so that we
5395 * could attach the new rb, we could have missed a wakeup.
5398 wake_up_all(&event->waitq);
5402 static void ring_buffer_wakeup(struct perf_event *event)
5404 struct ring_buffer *rb;
5407 rb = rcu_dereference(event->rb);
5409 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5410 wake_up_all(&event->waitq);
5415 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5417 struct ring_buffer *rb;
5420 rb = rcu_dereference(event->rb);
5422 if (!refcount_inc_not_zero(&rb->refcount))
5430 void ring_buffer_put(struct ring_buffer *rb)
5432 if (!refcount_dec_and_test(&rb->refcount))
5435 WARN_ON_ONCE(!list_empty(&rb->event_list));
5437 call_rcu(&rb->rcu_head, rb_free_rcu);
5440 static void perf_mmap_open(struct vm_area_struct *vma)
5442 struct perf_event *event = vma->vm_file->private_data;
5444 atomic_inc(&event->mmap_count);
5445 atomic_inc(&event->rb->mmap_count);
5448 atomic_inc(&event->rb->aux_mmap_count);
5450 if (event->pmu->event_mapped)
5451 event->pmu->event_mapped(event, vma->vm_mm);
5454 static void perf_pmu_output_stop(struct perf_event *event);
5457 * A buffer can be mmap()ed multiple times; either directly through the same
5458 * event, or through other events by use of perf_event_set_output().
5460 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5461 * the buffer here, where we still have a VM context. This means we need
5462 * to detach all events redirecting to us.
5464 static void perf_mmap_close(struct vm_area_struct *vma)
5466 struct perf_event *event = vma->vm_file->private_data;
5468 struct ring_buffer *rb = ring_buffer_get(event);
5469 struct user_struct *mmap_user = rb->mmap_user;
5470 int mmap_locked = rb->mmap_locked;
5471 unsigned long size = perf_data_size(rb);
5473 if (event->pmu->event_unmapped)
5474 event->pmu->event_unmapped(event, vma->vm_mm);
5477 * rb->aux_mmap_count will always drop before rb->mmap_count and
5478 * event->mmap_count, so it is ok to use event->mmap_mutex to
5479 * serialize with perf_mmap here.
5481 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5482 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5484 * Stop all AUX events that are writing to this buffer,
5485 * so that we can free its AUX pages and corresponding PMU
5486 * data. Note that after rb::aux_mmap_count dropped to zero,
5487 * they won't start any more (see perf_aux_output_begin()).
5489 perf_pmu_output_stop(event);
5491 /* now it's safe to free the pages */
5492 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5493 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5495 /* this has to be the last one */
5497 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5499 mutex_unlock(&event->mmap_mutex);
5502 atomic_dec(&rb->mmap_count);
5504 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5507 ring_buffer_attach(event, NULL);
5508 mutex_unlock(&event->mmap_mutex);
5510 /* If there's still other mmap()s of this buffer, we're done. */
5511 if (atomic_read(&rb->mmap_count))
5515 * No other mmap()s, detach from all other events that might redirect
5516 * into the now unreachable buffer. Somewhat complicated by the
5517 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5521 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5522 if (!atomic_long_inc_not_zero(&event->refcount)) {
5524 * This event is en-route to free_event() which will
5525 * detach it and remove it from the list.
5531 mutex_lock(&event->mmap_mutex);
5533 * Check we didn't race with perf_event_set_output() which can
5534 * swizzle the rb from under us while we were waiting to
5535 * acquire mmap_mutex.
5537 * If we find a different rb; ignore this event, a next
5538 * iteration will no longer find it on the list. We have to
5539 * still restart the iteration to make sure we're not now
5540 * iterating the wrong list.
5542 if (event->rb == rb)
5543 ring_buffer_attach(event, NULL);
5545 mutex_unlock(&event->mmap_mutex);
5549 * Restart the iteration; either we're on the wrong list or
5550 * destroyed its integrity by doing a deletion.
5557 * It could be there's still a few 0-ref events on the list; they'll
5558 * get cleaned up by free_event() -- they'll also still have their
5559 * ref on the rb and will free it whenever they are done with it.
5561 * Aside from that, this buffer is 'fully' detached and unmapped,
5562 * undo the VM accounting.
5565 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5566 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5567 free_uid(mmap_user);
5570 ring_buffer_put(rb); /* could be last */
5573 static const struct vm_operations_struct perf_mmap_vmops = {
5574 .open = perf_mmap_open,
5575 .close = perf_mmap_close, /* non mergeable */
5576 .fault = perf_mmap_fault,
5577 .page_mkwrite = perf_mmap_fault,
5580 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5582 struct perf_event *event = file->private_data;
5583 unsigned long user_locked, user_lock_limit;
5584 struct user_struct *user = current_user();
5585 unsigned long locked, lock_limit;
5586 struct ring_buffer *rb = NULL;
5587 unsigned long vma_size;
5588 unsigned long nr_pages;
5589 long user_extra = 0, extra = 0;
5590 int ret = 0, flags = 0;
5593 * Don't allow mmap() of inherited per-task counters. This would
5594 * create a performance issue due to all children writing to the
5597 if (event->cpu == -1 && event->attr.inherit)
5600 if (!(vma->vm_flags & VM_SHARED))
5603 vma_size = vma->vm_end - vma->vm_start;
5605 if (vma->vm_pgoff == 0) {
5606 nr_pages = (vma_size / PAGE_SIZE) - 1;
5609 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5610 * mapped, all subsequent mappings should have the same size
5611 * and offset. Must be above the normal perf buffer.
5613 u64 aux_offset, aux_size;
5618 nr_pages = vma_size / PAGE_SIZE;
5620 mutex_lock(&event->mmap_mutex);
5627 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5628 aux_size = READ_ONCE(rb->user_page->aux_size);
5630 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5633 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5636 /* already mapped with a different offset */
5637 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5640 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5643 /* already mapped with a different size */
5644 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5647 if (!is_power_of_2(nr_pages))
5650 if (!atomic_inc_not_zero(&rb->mmap_count))
5653 if (rb_has_aux(rb)) {
5654 atomic_inc(&rb->aux_mmap_count);
5659 atomic_set(&rb->aux_mmap_count, 1);
5660 user_extra = nr_pages;
5666 * If we have rb pages ensure they're a power-of-two number, so we
5667 * can do bitmasks instead of modulo.
5669 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5672 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5675 WARN_ON_ONCE(event->ctx->parent_ctx);
5677 mutex_lock(&event->mmap_mutex);
5679 if (event->rb->nr_pages != nr_pages) {
5684 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5686 * Raced against perf_mmap_close() through
5687 * perf_event_set_output(). Try again, hope for better
5690 mutex_unlock(&event->mmap_mutex);
5697 user_extra = nr_pages + 1;
5700 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5703 * Increase the limit linearly with more CPUs:
5705 user_lock_limit *= num_online_cpus();
5707 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5709 if (user_locked > user_lock_limit)
5710 extra = user_locked - user_lock_limit;
5712 lock_limit = rlimit(RLIMIT_MEMLOCK);
5713 lock_limit >>= PAGE_SHIFT;
5714 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5716 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5717 !capable(CAP_IPC_LOCK)) {
5722 WARN_ON(!rb && event->rb);
5724 if (vma->vm_flags & VM_WRITE)
5725 flags |= RING_BUFFER_WRITABLE;
5728 rb = rb_alloc(nr_pages,
5729 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5737 atomic_set(&rb->mmap_count, 1);
5738 rb->mmap_user = get_current_user();
5739 rb->mmap_locked = extra;
5741 ring_buffer_attach(event, rb);
5743 perf_event_init_userpage(event);
5744 perf_event_update_userpage(event);
5746 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5747 event->attr.aux_watermark, flags);
5749 rb->aux_mmap_locked = extra;
5754 atomic_long_add(user_extra, &user->locked_vm);
5755 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5757 atomic_inc(&event->mmap_count);
5759 atomic_dec(&rb->mmap_count);
5762 mutex_unlock(&event->mmap_mutex);
5765 * Since pinned accounting is per vm we cannot allow fork() to copy our
5768 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5769 vma->vm_ops = &perf_mmap_vmops;
5771 if (event->pmu->event_mapped)
5772 event->pmu->event_mapped(event, vma->vm_mm);
5777 static int perf_fasync(int fd, struct file *filp, int on)
5779 struct inode *inode = file_inode(filp);
5780 struct perf_event *event = filp->private_data;
5784 retval = fasync_helper(fd, filp, on, &event->fasync);
5785 inode_unlock(inode);
5793 static const struct file_operations perf_fops = {
5794 .llseek = no_llseek,
5795 .release = perf_release,
5798 .unlocked_ioctl = perf_ioctl,
5799 .compat_ioctl = perf_compat_ioctl,
5801 .fasync = perf_fasync,
5807 * If there's data, ensure we set the poll() state and publish everything
5808 * to user-space before waking everybody up.
5811 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5813 /* only the parent has fasync state */
5815 event = event->parent;
5816 return &event->fasync;
5819 void perf_event_wakeup(struct perf_event *event)
5821 ring_buffer_wakeup(event);
5823 if (event->pending_kill) {
5824 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5825 event->pending_kill = 0;
5829 static void perf_pending_event_disable(struct perf_event *event)
5831 int cpu = READ_ONCE(event->pending_disable);
5836 if (cpu == smp_processor_id()) {
5837 WRITE_ONCE(event->pending_disable, -1);
5838 perf_event_disable_local(event);
5845 * perf_event_disable_inatomic()
5846 * @pending_disable = CPU-A;
5850 * @pending_disable = -1;
5853 * perf_event_disable_inatomic()
5854 * @pending_disable = CPU-B;
5855 * irq_work_queue(); // FAILS
5858 * perf_pending_event()
5860 * But the event runs on CPU-B and wants disabling there.
5862 irq_work_queue_on(&event->pending, cpu);
5865 static void perf_pending_event(struct irq_work *entry)
5867 struct perf_event *event = container_of(entry, struct perf_event, pending);
5870 rctx = perf_swevent_get_recursion_context();
5872 * If we 'fail' here, that's OK, it means recursion is already disabled
5873 * and we won't recurse 'further'.
5876 perf_pending_event_disable(event);
5878 if (event->pending_wakeup) {
5879 event->pending_wakeup = 0;
5880 perf_event_wakeup(event);
5884 perf_swevent_put_recursion_context(rctx);
5888 * We assume there is only KVM supporting the callbacks.
5889 * Later on, we might change it to a list if there is
5890 * another virtualization implementation supporting the callbacks.
5892 struct perf_guest_info_callbacks *perf_guest_cbs;
5894 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5896 perf_guest_cbs = cbs;
5899 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5901 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5903 perf_guest_cbs = NULL;
5906 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5909 perf_output_sample_regs(struct perf_output_handle *handle,
5910 struct pt_regs *regs, u64 mask)
5913 DECLARE_BITMAP(_mask, 64);
5915 bitmap_from_u64(_mask, mask);
5916 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5919 val = perf_reg_value(regs, bit);
5920 perf_output_put(handle, val);
5924 static void perf_sample_regs_user(struct perf_regs *regs_user,
5925 struct pt_regs *regs,
5926 struct pt_regs *regs_user_copy)
5928 if (user_mode(regs)) {
5929 regs_user->abi = perf_reg_abi(current);
5930 regs_user->regs = regs;
5931 } else if (!(current->flags & PF_KTHREAD)) {
5932 perf_get_regs_user(regs_user, regs, regs_user_copy);
5934 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5935 regs_user->regs = NULL;
5939 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5940 struct pt_regs *regs)
5942 regs_intr->regs = regs;
5943 regs_intr->abi = perf_reg_abi(current);
5948 * Get remaining task size from user stack pointer.
5950 * It'd be better to take stack vma map and limit this more
5951 * precisly, but there's no way to get it safely under interrupt,
5952 * so using TASK_SIZE as limit.
5954 static u64 perf_ustack_task_size(struct pt_regs *regs)
5956 unsigned long addr = perf_user_stack_pointer(regs);
5958 if (!addr || addr >= TASK_SIZE)
5961 return TASK_SIZE - addr;
5965 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5966 struct pt_regs *regs)
5970 /* No regs, no stack pointer, no dump. */
5975 * Check if we fit in with the requested stack size into the:
5977 * If we don't, we limit the size to the TASK_SIZE.
5979 * - remaining sample size
5980 * If we don't, we customize the stack size to
5981 * fit in to the remaining sample size.
5984 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5985 stack_size = min(stack_size, (u16) task_size);
5987 /* Current header size plus static size and dynamic size. */
5988 header_size += 2 * sizeof(u64);
5990 /* Do we fit in with the current stack dump size? */
5991 if ((u16) (header_size + stack_size) < header_size) {
5993 * If we overflow the maximum size for the sample,
5994 * we customize the stack dump size to fit in.
5996 stack_size = USHRT_MAX - header_size - sizeof(u64);
5997 stack_size = round_up(stack_size, sizeof(u64));
6004 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6005 struct pt_regs *regs)
6007 /* Case of a kernel thread, nothing to dump */
6010 perf_output_put(handle, size);
6020 * - the size requested by user or the best one we can fit
6021 * in to the sample max size
6023 * - user stack dump data
6025 * - the actual dumped size
6029 perf_output_put(handle, dump_size);
6032 sp = perf_user_stack_pointer(regs);
6035 rem = __output_copy_user(handle, (void *) sp, dump_size);
6037 dyn_size = dump_size - rem;
6039 perf_output_skip(handle, rem);
6042 perf_output_put(handle, dyn_size);
6046 static void __perf_event_header__init_id(struct perf_event_header *header,
6047 struct perf_sample_data *data,
6048 struct perf_event *event)
6050 u64 sample_type = event->attr.sample_type;
6052 data->type = sample_type;
6053 header->size += event->id_header_size;
6055 if (sample_type & PERF_SAMPLE_TID) {
6056 /* namespace issues */
6057 data->tid_entry.pid = perf_event_pid(event, current);
6058 data->tid_entry.tid = perf_event_tid(event, current);
6061 if (sample_type & PERF_SAMPLE_TIME)
6062 data->time = perf_event_clock(event);
6064 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6065 data->id = primary_event_id(event);
6067 if (sample_type & PERF_SAMPLE_STREAM_ID)
6068 data->stream_id = event->id;
6070 if (sample_type & PERF_SAMPLE_CPU) {
6071 data->cpu_entry.cpu = raw_smp_processor_id();
6072 data->cpu_entry.reserved = 0;
6076 void perf_event_header__init_id(struct perf_event_header *header,
6077 struct perf_sample_data *data,
6078 struct perf_event *event)
6080 if (event->attr.sample_id_all)
6081 __perf_event_header__init_id(header, data, event);
6084 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6085 struct perf_sample_data *data)
6087 u64 sample_type = data->type;
6089 if (sample_type & PERF_SAMPLE_TID)
6090 perf_output_put(handle, data->tid_entry);
6092 if (sample_type & PERF_SAMPLE_TIME)
6093 perf_output_put(handle, data->time);
6095 if (sample_type & PERF_SAMPLE_ID)
6096 perf_output_put(handle, data->id);
6098 if (sample_type & PERF_SAMPLE_STREAM_ID)
6099 perf_output_put(handle, data->stream_id);
6101 if (sample_type & PERF_SAMPLE_CPU)
6102 perf_output_put(handle, data->cpu_entry);
6104 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6105 perf_output_put(handle, data->id);
6108 void perf_event__output_id_sample(struct perf_event *event,
6109 struct perf_output_handle *handle,
6110 struct perf_sample_data *sample)
6112 if (event->attr.sample_id_all)
6113 __perf_event__output_id_sample(handle, sample);
6116 static void perf_output_read_one(struct perf_output_handle *handle,
6117 struct perf_event *event,
6118 u64 enabled, u64 running)
6120 u64 read_format = event->attr.read_format;
6124 values[n++] = perf_event_count(event);
6125 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6126 values[n++] = enabled +
6127 atomic64_read(&event->child_total_time_enabled);
6129 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6130 values[n++] = running +
6131 atomic64_read(&event->child_total_time_running);
6133 if (read_format & PERF_FORMAT_ID)
6134 values[n++] = primary_event_id(event);
6136 __output_copy(handle, values, n * sizeof(u64));
6139 static void perf_output_read_group(struct perf_output_handle *handle,
6140 struct perf_event *event,
6141 u64 enabled, u64 running)
6143 struct perf_event *leader = event->group_leader, *sub;
6144 u64 read_format = event->attr.read_format;
6148 values[n++] = 1 + leader->nr_siblings;
6150 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6151 values[n++] = enabled;
6153 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6154 values[n++] = running;
6156 if ((leader != event) &&
6157 (leader->state == PERF_EVENT_STATE_ACTIVE))
6158 leader->pmu->read(leader);
6160 values[n++] = perf_event_count(leader);
6161 if (read_format & PERF_FORMAT_ID)
6162 values[n++] = primary_event_id(leader);
6164 __output_copy(handle, values, n * sizeof(u64));
6166 for_each_sibling_event(sub, leader) {
6169 if ((sub != event) &&
6170 (sub->state == PERF_EVENT_STATE_ACTIVE))
6171 sub->pmu->read(sub);
6173 values[n++] = perf_event_count(sub);
6174 if (read_format & PERF_FORMAT_ID)
6175 values[n++] = primary_event_id(sub);
6177 __output_copy(handle, values, n * sizeof(u64));
6181 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6182 PERF_FORMAT_TOTAL_TIME_RUNNING)
6185 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6187 * The problem is that its both hard and excessively expensive to iterate the
6188 * child list, not to mention that its impossible to IPI the children running
6189 * on another CPU, from interrupt/NMI context.
6191 static void perf_output_read(struct perf_output_handle *handle,
6192 struct perf_event *event)
6194 u64 enabled = 0, running = 0, now;
6195 u64 read_format = event->attr.read_format;
6198 * compute total_time_enabled, total_time_running
6199 * based on snapshot values taken when the event
6200 * was last scheduled in.
6202 * we cannot simply called update_context_time()
6203 * because of locking issue as we are called in
6206 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6207 calc_timer_values(event, &now, &enabled, &running);
6209 if (event->attr.read_format & PERF_FORMAT_GROUP)
6210 perf_output_read_group(handle, event, enabled, running);
6212 perf_output_read_one(handle, event, enabled, running);
6215 void perf_output_sample(struct perf_output_handle *handle,
6216 struct perf_event_header *header,
6217 struct perf_sample_data *data,
6218 struct perf_event *event)
6220 u64 sample_type = data->type;
6222 perf_output_put(handle, *header);
6224 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6225 perf_output_put(handle, data->id);
6227 if (sample_type & PERF_SAMPLE_IP)
6228 perf_output_put(handle, data->ip);
6230 if (sample_type & PERF_SAMPLE_TID)
6231 perf_output_put(handle, data->tid_entry);
6233 if (sample_type & PERF_SAMPLE_TIME)
6234 perf_output_put(handle, data->time);
6236 if (sample_type & PERF_SAMPLE_ADDR)
6237 perf_output_put(handle, data->addr);
6239 if (sample_type & PERF_SAMPLE_ID)
6240 perf_output_put(handle, data->id);
6242 if (sample_type & PERF_SAMPLE_STREAM_ID)
6243 perf_output_put(handle, data->stream_id);
6245 if (sample_type & PERF_SAMPLE_CPU)
6246 perf_output_put(handle, data->cpu_entry);
6248 if (sample_type & PERF_SAMPLE_PERIOD)
6249 perf_output_put(handle, data->period);
6251 if (sample_type & PERF_SAMPLE_READ)
6252 perf_output_read(handle, event);
6254 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6257 size += data->callchain->nr;
6258 size *= sizeof(u64);
6259 __output_copy(handle, data->callchain, size);
6262 if (sample_type & PERF_SAMPLE_RAW) {
6263 struct perf_raw_record *raw = data->raw;
6266 struct perf_raw_frag *frag = &raw->frag;
6268 perf_output_put(handle, raw->size);
6271 __output_custom(handle, frag->copy,
6272 frag->data, frag->size);
6274 __output_copy(handle, frag->data,
6277 if (perf_raw_frag_last(frag))
6282 __output_skip(handle, NULL, frag->pad);
6288 .size = sizeof(u32),
6291 perf_output_put(handle, raw);
6295 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6296 if (data->br_stack) {
6299 size = data->br_stack->nr
6300 * sizeof(struct perf_branch_entry);
6302 perf_output_put(handle, data->br_stack->nr);
6303 perf_output_copy(handle, data->br_stack->entries, size);
6306 * we always store at least the value of nr
6309 perf_output_put(handle, nr);
6313 if (sample_type & PERF_SAMPLE_REGS_USER) {
6314 u64 abi = data->regs_user.abi;
6317 * If there are no regs to dump, notice it through
6318 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6320 perf_output_put(handle, abi);
6323 u64 mask = event->attr.sample_regs_user;
6324 perf_output_sample_regs(handle,
6325 data->regs_user.regs,
6330 if (sample_type & PERF_SAMPLE_STACK_USER) {
6331 perf_output_sample_ustack(handle,
6332 data->stack_user_size,
6333 data->regs_user.regs);
6336 if (sample_type & PERF_SAMPLE_WEIGHT)
6337 perf_output_put(handle, data->weight);
6339 if (sample_type & PERF_SAMPLE_DATA_SRC)
6340 perf_output_put(handle, data->data_src.val);
6342 if (sample_type & PERF_SAMPLE_TRANSACTION)
6343 perf_output_put(handle, data->txn);
6345 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6346 u64 abi = data->regs_intr.abi;
6348 * If there are no regs to dump, notice it through
6349 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6351 perf_output_put(handle, abi);
6354 u64 mask = event->attr.sample_regs_intr;
6356 perf_output_sample_regs(handle,
6357 data->regs_intr.regs,
6362 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6363 perf_output_put(handle, data->phys_addr);
6365 if (!event->attr.watermark) {
6366 int wakeup_events = event->attr.wakeup_events;
6368 if (wakeup_events) {
6369 struct ring_buffer *rb = handle->rb;
6370 int events = local_inc_return(&rb->events);
6372 if (events >= wakeup_events) {
6373 local_sub(wakeup_events, &rb->events);
6374 local_inc(&rb->wakeup);
6380 static u64 perf_virt_to_phys(u64 virt)
6383 struct page *p = NULL;
6388 if (virt >= TASK_SIZE) {
6389 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6390 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6391 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6392 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6395 * Walking the pages tables for user address.
6396 * Interrupts are disabled, so it prevents any tear down
6397 * of the page tables.
6398 * Try IRQ-safe __get_user_pages_fast first.
6399 * If failed, leave phys_addr as 0.
6401 if ((current->mm != NULL) &&
6402 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6403 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6412 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6414 struct perf_callchain_entry *
6415 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6417 bool kernel = !event->attr.exclude_callchain_kernel;
6418 bool user = !event->attr.exclude_callchain_user;
6419 /* Disallow cross-task user callchains. */
6420 bool crosstask = event->ctx->task && event->ctx->task != current;
6421 const u32 max_stack = event->attr.sample_max_stack;
6422 struct perf_callchain_entry *callchain;
6424 if (!kernel && !user)
6425 return &__empty_callchain;
6427 callchain = get_perf_callchain(regs, 0, kernel, user,
6428 max_stack, crosstask, true);
6429 return callchain ?: &__empty_callchain;
6432 void perf_prepare_sample(struct perf_event_header *header,
6433 struct perf_sample_data *data,
6434 struct perf_event *event,
6435 struct pt_regs *regs)
6437 u64 sample_type = event->attr.sample_type;
6439 header->type = PERF_RECORD_SAMPLE;
6440 header->size = sizeof(*header) + event->header_size;
6443 header->misc |= perf_misc_flags(regs);
6445 __perf_event_header__init_id(header, data, event);
6447 if (sample_type & PERF_SAMPLE_IP)
6448 data->ip = perf_instruction_pointer(regs);
6450 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6453 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6454 data->callchain = perf_callchain(event, regs);
6456 size += data->callchain->nr;
6458 header->size += size * sizeof(u64);
6461 if (sample_type & PERF_SAMPLE_RAW) {
6462 struct perf_raw_record *raw = data->raw;
6466 struct perf_raw_frag *frag = &raw->frag;
6471 if (perf_raw_frag_last(frag))
6476 size = round_up(sum + sizeof(u32), sizeof(u64));
6477 raw->size = size - sizeof(u32);
6478 frag->pad = raw->size - sum;
6483 header->size += size;
6486 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6487 int size = sizeof(u64); /* nr */
6488 if (data->br_stack) {
6489 size += data->br_stack->nr
6490 * sizeof(struct perf_branch_entry);
6492 header->size += size;
6495 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6496 perf_sample_regs_user(&data->regs_user, regs,
6497 &data->regs_user_copy);
6499 if (sample_type & PERF_SAMPLE_REGS_USER) {
6500 /* regs dump ABI info */
6501 int size = sizeof(u64);
6503 if (data->regs_user.regs) {
6504 u64 mask = event->attr.sample_regs_user;
6505 size += hweight64(mask) * sizeof(u64);
6508 header->size += size;
6511 if (sample_type & PERF_SAMPLE_STACK_USER) {
6513 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6514 * processed as the last one or have additional check added
6515 * in case new sample type is added, because we could eat
6516 * up the rest of the sample size.
6518 u16 stack_size = event->attr.sample_stack_user;
6519 u16 size = sizeof(u64);
6521 stack_size = perf_sample_ustack_size(stack_size, header->size,
6522 data->regs_user.regs);
6525 * If there is something to dump, add space for the dump
6526 * itself and for the field that tells the dynamic size,
6527 * which is how many have been actually dumped.
6530 size += sizeof(u64) + stack_size;
6532 data->stack_user_size = stack_size;
6533 header->size += size;
6536 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6537 /* regs dump ABI info */
6538 int size = sizeof(u64);
6540 perf_sample_regs_intr(&data->regs_intr, regs);
6542 if (data->regs_intr.regs) {
6543 u64 mask = event->attr.sample_regs_intr;
6545 size += hweight64(mask) * sizeof(u64);
6548 header->size += size;
6551 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6552 data->phys_addr = perf_virt_to_phys(data->addr);
6555 static __always_inline int
6556 __perf_event_output(struct perf_event *event,
6557 struct perf_sample_data *data,
6558 struct pt_regs *regs,
6559 int (*output_begin)(struct perf_output_handle *,
6560 struct perf_event *,
6563 struct perf_output_handle handle;
6564 struct perf_event_header header;
6567 /* protect the callchain buffers */
6570 perf_prepare_sample(&header, data, event, regs);
6572 err = output_begin(&handle, event, header.size);
6576 perf_output_sample(&handle, &header, data, event);
6578 perf_output_end(&handle);
6586 perf_event_output_forward(struct perf_event *event,
6587 struct perf_sample_data *data,
6588 struct pt_regs *regs)
6590 __perf_event_output(event, data, regs, perf_output_begin_forward);
6594 perf_event_output_backward(struct perf_event *event,
6595 struct perf_sample_data *data,
6596 struct pt_regs *regs)
6598 __perf_event_output(event, data, regs, perf_output_begin_backward);
6602 perf_event_output(struct perf_event *event,
6603 struct perf_sample_data *data,
6604 struct pt_regs *regs)
6606 return __perf_event_output(event, data, regs, perf_output_begin);
6613 struct perf_read_event {
6614 struct perf_event_header header;
6621 perf_event_read_event(struct perf_event *event,
6622 struct task_struct *task)
6624 struct perf_output_handle handle;
6625 struct perf_sample_data sample;
6626 struct perf_read_event read_event = {
6628 .type = PERF_RECORD_READ,
6630 .size = sizeof(read_event) + event->read_size,
6632 .pid = perf_event_pid(event, task),
6633 .tid = perf_event_tid(event, task),
6637 perf_event_header__init_id(&read_event.header, &sample, event);
6638 ret = perf_output_begin(&handle, event, read_event.header.size);
6642 perf_output_put(&handle, read_event);
6643 perf_output_read(&handle, event);
6644 perf_event__output_id_sample(event, &handle, &sample);
6646 perf_output_end(&handle);
6649 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6652 perf_iterate_ctx(struct perf_event_context *ctx,
6653 perf_iterate_f output,
6654 void *data, bool all)
6656 struct perf_event *event;
6658 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6660 if (event->state < PERF_EVENT_STATE_INACTIVE)
6662 if (!event_filter_match(event))
6666 output(event, data);
6670 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6672 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6673 struct perf_event *event;
6675 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6677 * Skip events that are not fully formed yet; ensure that
6678 * if we observe event->ctx, both event and ctx will be
6679 * complete enough. See perf_install_in_context().
6681 if (!smp_load_acquire(&event->ctx))
6684 if (event->state < PERF_EVENT_STATE_INACTIVE)
6686 if (!event_filter_match(event))
6688 output(event, data);
6693 * Iterate all events that need to receive side-band events.
6695 * For new callers; ensure that account_pmu_sb_event() includes
6696 * your event, otherwise it might not get delivered.
6699 perf_iterate_sb(perf_iterate_f output, void *data,
6700 struct perf_event_context *task_ctx)
6702 struct perf_event_context *ctx;
6709 * If we have task_ctx != NULL we only notify the task context itself.
6710 * The task_ctx is set only for EXIT events before releasing task
6714 perf_iterate_ctx(task_ctx, output, data, false);
6718 perf_iterate_sb_cpu(output, data);
6720 for_each_task_context_nr(ctxn) {
6721 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6723 perf_iterate_ctx(ctx, output, data, false);
6731 * Clear all file-based filters at exec, they'll have to be
6732 * re-instated when/if these objects are mmapped again.
6734 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6736 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6737 struct perf_addr_filter *filter;
6738 unsigned int restart = 0, count = 0;
6739 unsigned long flags;
6741 if (!has_addr_filter(event))
6744 raw_spin_lock_irqsave(&ifh->lock, flags);
6745 list_for_each_entry(filter, &ifh->list, entry) {
6746 if (filter->path.dentry) {
6747 event->addr_filter_ranges[count].start = 0;
6748 event->addr_filter_ranges[count].size = 0;
6756 event->addr_filters_gen++;
6757 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6760 perf_event_stop(event, 1);
6763 void perf_event_exec(void)
6765 struct perf_event_context *ctx;
6769 for_each_task_context_nr(ctxn) {
6770 ctx = current->perf_event_ctxp[ctxn];
6774 perf_event_enable_on_exec(ctxn);
6776 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6782 struct remote_output {
6783 struct ring_buffer *rb;
6787 static void __perf_event_output_stop(struct perf_event *event, void *data)
6789 struct perf_event *parent = event->parent;
6790 struct remote_output *ro = data;
6791 struct ring_buffer *rb = ro->rb;
6792 struct stop_event_data sd = {
6796 if (!has_aux(event))
6803 * In case of inheritance, it will be the parent that links to the
6804 * ring-buffer, but it will be the child that's actually using it.
6806 * We are using event::rb to determine if the event should be stopped,
6807 * however this may race with ring_buffer_attach() (through set_output),
6808 * which will make us skip the event that actually needs to be stopped.
6809 * So ring_buffer_attach() has to stop an aux event before re-assigning
6812 if (rcu_dereference(parent->rb) == rb)
6813 ro->err = __perf_event_stop(&sd);
6816 static int __perf_pmu_output_stop(void *info)
6818 struct perf_event *event = info;
6819 struct pmu *pmu = event->pmu;
6820 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6821 struct remote_output ro = {
6826 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6827 if (cpuctx->task_ctx)
6828 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6835 static void perf_pmu_output_stop(struct perf_event *event)
6837 struct perf_event *iter;
6842 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6844 * For per-CPU events, we need to make sure that neither they
6845 * nor their children are running; for cpu==-1 events it's
6846 * sufficient to stop the event itself if it's active, since
6847 * it can't have children.
6851 cpu = READ_ONCE(iter->oncpu);
6856 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6857 if (err == -EAGAIN) {
6866 * task tracking -- fork/exit
6868 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6871 struct perf_task_event {
6872 struct task_struct *task;
6873 struct perf_event_context *task_ctx;
6876 struct perf_event_header header;
6886 static int perf_event_task_match(struct perf_event *event)
6888 return event->attr.comm || event->attr.mmap ||
6889 event->attr.mmap2 || event->attr.mmap_data ||
6893 static void perf_event_task_output(struct perf_event *event,
6896 struct perf_task_event *task_event = data;
6897 struct perf_output_handle handle;
6898 struct perf_sample_data sample;
6899 struct task_struct *task = task_event->task;
6900 int ret, size = task_event->event_id.header.size;
6902 if (!perf_event_task_match(event))
6905 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6907 ret = perf_output_begin(&handle, event,
6908 task_event->event_id.header.size);
6912 task_event->event_id.pid = perf_event_pid(event, task);
6913 task_event->event_id.ppid = perf_event_pid(event, current);
6915 task_event->event_id.tid = perf_event_tid(event, task);
6916 task_event->event_id.ptid = perf_event_tid(event, current);
6918 task_event->event_id.time = perf_event_clock(event);
6920 perf_output_put(&handle, task_event->event_id);
6922 perf_event__output_id_sample(event, &handle, &sample);
6924 perf_output_end(&handle);
6926 task_event->event_id.header.size = size;
6929 static void perf_event_task(struct task_struct *task,
6930 struct perf_event_context *task_ctx,
6933 struct perf_task_event task_event;
6935 if (!atomic_read(&nr_comm_events) &&
6936 !atomic_read(&nr_mmap_events) &&
6937 !atomic_read(&nr_task_events))
6940 task_event = (struct perf_task_event){
6942 .task_ctx = task_ctx,
6945 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6947 .size = sizeof(task_event.event_id),
6957 perf_iterate_sb(perf_event_task_output,
6962 void perf_event_fork(struct task_struct *task)
6964 perf_event_task(task, NULL, 1);
6965 perf_event_namespaces(task);
6972 struct perf_comm_event {
6973 struct task_struct *task;
6978 struct perf_event_header header;
6985 static int perf_event_comm_match(struct perf_event *event)
6987 return event->attr.comm;
6990 static void perf_event_comm_output(struct perf_event *event,
6993 struct perf_comm_event *comm_event = data;
6994 struct perf_output_handle handle;
6995 struct perf_sample_data sample;
6996 int size = comm_event->event_id.header.size;
6999 if (!perf_event_comm_match(event))
7002 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7003 ret = perf_output_begin(&handle, event,
7004 comm_event->event_id.header.size);
7009 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7010 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7012 perf_output_put(&handle, comm_event->event_id);
7013 __output_copy(&handle, comm_event->comm,
7014 comm_event->comm_size);
7016 perf_event__output_id_sample(event, &handle, &sample);
7018 perf_output_end(&handle);
7020 comm_event->event_id.header.size = size;
7023 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7025 char comm[TASK_COMM_LEN];
7028 memset(comm, 0, sizeof(comm));
7029 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7030 size = ALIGN(strlen(comm)+1, sizeof(u64));
7032 comm_event->comm = comm;
7033 comm_event->comm_size = size;
7035 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7037 perf_iterate_sb(perf_event_comm_output,
7042 void perf_event_comm(struct task_struct *task, bool exec)
7044 struct perf_comm_event comm_event;
7046 if (!atomic_read(&nr_comm_events))
7049 comm_event = (struct perf_comm_event){
7055 .type = PERF_RECORD_COMM,
7056 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7064 perf_event_comm_event(&comm_event);
7068 * namespaces tracking
7071 struct perf_namespaces_event {
7072 struct task_struct *task;
7075 struct perf_event_header header;
7080 struct perf_ns_link_info link_info[NR_NAMESPACES];
7084 static int perf_event_namespaces_match(struct perf_event *event)
7086 return event->attr.namespaces;
7089 static void perf_event_namespaces_output(struct perf_event *event,
7092 struct perf_namespaces_event *namespaces_event = data;
7093 struct perf_output_handle handle;
7094 struct perf_sample_data sample;
7095 u16 header_size = namespaces_event->event_id.header.size;
7098 if (!perf_event_namespaces_match(event))
7101 perf_event_header__init_id(&namespaces_event->event_id.header,
7103 ret = perf_output_begin(&handle, event,
7104 namespaces_event->event_id.header.size);
7108 namespaces_event->event_id.pid = perf_event_pid(event,
7109 namespaces_event->task);
7110 namespaces_event->event_id.tid = perf_event_tid(event,
7111 namespaces_event->task);
7113 perf_output_put(&handle, namespaces_event->event_id);
7115 perf_event__output_id_sample(event, &handle, &sample);
7117 perf_output_end(&handle);
7119 namespaces_event->event_id.header.size = header_size;
7122 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7123 struct task_struct *task,
7124 const struct proc_ns_operations *ns_ops)
7126 struct path ns_path;
7127 struct inode *ns_inode;
7130 error = ns_get_path(&ns_path, task, ns_ops);
7132 ns_inode = ns_path.dentry->d_inode;
7133 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7134 ns_link_info->ino = ns_inode->i_ino;
7139 void perf_event_namespaces(struct task_struct *task)
7141 struct perf_namespaces_event namespaces_event;
7142 struct perf_ns_link_info *ns_link_info;
7144 if (!atomic_read(&nr_namespaces_events))
7147 namespaces_event = (struct perf_namespaces_event){
7151 .type = PERF_RECORD_NAMESPACES,
7153 .size = sizeof(namespaces_event.event_id),
7157 .nr_namespaces = NR_NAMESPACES,
7158 /* .link_info[NR_NAMESPACES] */
7162 ns_link_info = namespaces_event.event_id.link_info;
7164 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7165 task, &mntns_operations);
7167 #ifdef CONFIG_USER_NS
7168 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7169 task, &userns_operations);
7171 #ifdef CONFIG_NET_NS
7172 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7173 task, &netns_operations);
7175 #ifdef CONFIG_UTS_NS
7176 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7177 task, &utsns_operations);
7179 #ifdef CONFIG_IPC_NS
7180 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7181 task, &ipcns_operations);
7183 #ifdef CONFIG_PID_NS
7184 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7185 task, &pidns_operations);
7187 #ifdef CONFIG_CGROUPS
7188 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7189 task, &cgroupns_operations);
7192 perf_iterate_sb(perf_event_namespaces_output,
7201 struct perf_mmap_event {
7202 struct vm_area_struct *vma;
7204 const char *file_name;
7212 struct perf_event_header header;
7222 static int perf_event_mmap_match(struct perf_event *event,
7225 struct perf_mmap_event *mmap_event = data;
7226 struct vm_area_struct *vma = mmap_event->vma;
7227 int executable = vma->vm_flags & VM_EXEC;
7229 return (!executable && event->attr.mmap_data) ||
7230 (executable && (event->attr.mmap || event->attr.mmap2));
7233 static void perf_event_mmap_output(struct perf_event *event,
7236 struct perf_mmap_event *mmap_event = data;
7237 struct perf_output_handle handle;
7238 struct perf_sample_data sample;
7239 int size = mmap_event->event_id.header.size;
7240 u32 type = mmap_event->event_id.header.type;
7243 if (!perf_event_mmap_match(event, data))
7246 if (event->attr.mmap2) {
7247 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7248 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7249 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7250 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7251 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7252 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7253 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7256 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7257 ret = perf_output_begin(&handle, event,
7258 mmap_event->event_id.header.size);
7262 mmap_event->event_id.pid = perf_event_pid(event, current);
7263 mmap_event->event_id.tid = perf_event_tid(event, current);
7265 perf_output_put(&handle, mmap_event->event_id);
7267 if (event->attr.mmap2) {
7268 perf_output_put(&handle, mmap_event->maj);
7269 perf_output_put(&handle, mmap_event->min);
7270 perf_output_put(&handle, mmap_event->ino);
7271 perf_output_put(&handle, mmap_event->ino_generation);
7272 perf_output_put(&handle, mmap_event->prot);
7273 perf_output_put(&handle, mmap_event->flags);
7276 __output_copy(&handle, mmap_event->file_name,
7277 mmap_event->file_size);
7279 perf_event__output_id_sample(event, &handle, &sample);
7281 perf_output_end(&handle);
7283 mmap_event->event_id.header.size = size;
7284 mmap_event->event_id.header.type = type;
7287 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7289 struct vm_area_struct *vma = mmap_event->vma;
7290 struct file *file = vma->vm_file;
7291 int maj = 0, min = 0;
7292 u64 ino = 0, gen = 0;
7293 u32 prot = 0, flags = 0;
7299 if (vma->vm_flags & VM_READ)
7301 if (vma->vm_flags & VM_WRITE)
7303 if (vma->vm_flags & VM_EXEC)
7306 if (vma->vm_flags & VM_MAYSHARE)
7309 flags = MAP_PRIVATE;
7311 if (vma->vm_flags & VM_DENYWRITE)
7312 flags |= MAP_DENYWRITE;
7313 if (vma->vm_flags & VM_MAYEXEC)
7314 flags |= MAP_EXECUTABLE;
7315 if (vma->vm_flags & VM_LOCKED)
7316 flags |= MAP_LOCKED;
7317 if (vma->vm_flags & VM_HUGETLB)
7318 flags |= MAP_HUGETLB;
7321 struct inode *inode;
7324 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7330 * d_path() works from the end of the rb backwards, so we
7331 * need to add enough zero bytes after the string to handle
7332 * the 64bit alignment we do later.
7334 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7339 inode = file_inode(vma->vm_file);
7340 dev = inode->i_sb->s_dev;
7342 gen = inode->i_generation;
7348 if (vma->vm_ops && vma->vm_ops->name) {
7349 name = (char *) vma->vm_ops->name(vma);
7354 name = (char *)arch_vma_name(vma);
7358 if (vma->vm_start <= vma->vm_mm->start_brk &&
7359 vma->vm_end >= vma->vm_mm->brk) {
7363 if (vma->vm_start <= vma->vm_mm->start_stack &&
7364 vma->vm_end >= vma->vm_mm->start_stack) {
7374 strlcpy(tmp, name, sizeof(tmp));
7378 * Since our buffer works in 8 byte units we need to align our string
7379 * size to a multiple of 8. However, we must guarantee the tail end is
7380 * zero'd out to avoid leaking random bits to userspace.
7382 size = strlen(name)+1;
7383 while (!IS_ALIGNED(size, sizeof(u64)))
7384 name[size++] = '\0';
7386 mmap_event->file_name = name;
7387 mmap_event->file_size = size;
7388 mmap_event->maj = maj;
7389 mmap_event->min = min;
7390 mmap_event->ino = ino;
7391 mmap_event->ino_generation = gen;
7392 mmap_event->prot = prot;
7393 mmap_event->flags = flags;
7395 if (!(vma->vm_flags & VM_EXEC))
7396 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7398 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7400 perf_iterate_sb(perf_event_mmap_output,
7408 * Check whether inode and address range match filter criteria.
7410 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7411 struct file *file, unsigned long offset,
7414 /* d_inode(NULL) won't be equal to any mapped user-space file */
7415 if (!filter->path.dentry)
7418 if (d_inode(filter->path.dentry) != file_inode(file))
7421 if (filter->offset > offset + size)
7424 if (filter->offset + filter->size < offset)
7430 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7431 struct vm_area_struct *vma,
7432 struct perf_addr_filter_range *fr)
7434 unsigned long vma_size = vma->vm_end - vma->vm_start;
7435 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7436 struct file *file = vma->vm_file;
7438 if (!perf_addr_filter_match(filter, file, off, vma_size))
7441 if (filter->offset < off) {
7442 fr->start = vma->vm_start;
7443 fr->size = min(vma_size, filter->size - (off - filter->offset));
7445 fr->start = vma->vm_start + filter->offset - off;
7446 fr->size = min(vma->vm_end - fr->start, filter->size);
7452 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7454 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7455 struct vm_area_struct *vma = data;
7456 struct perf_addr_filter *filter;
7457 unsigned int restart = 0, count = 0;
7458 unsigned long flags;
7460 if (!has_addr_filter(event))
7466 raw_spin_lock_irqsave(&ifh->lock, flags);
7467 list_for_each_entry(filter, &ifh->list, entry) {
7468 if (perf_addr_filter_vma_adjust(filter, vma,
7469 &event->addr_filter_ranges[count]))
7476 event->addr_filters_gen++;
7477 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7480 perf_event_stop(event, 1);
7484 * Adjust all task's events' filters to the new vma
7486 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7488 struct perf_event_context *ctx;
7492 * Data tracing isn't supported yet and as such there is no need
7493 * to keep track of anything that isn't related to executable code:
7495 if (!(vma->vm_flags & VM_EXEC))
7499 for_each_task_context_nr(ctxn) {
7500 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7504 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7509 void perf_event_mmap(struct vm_area_struct *vma)
7511 struct perf_mmap_event mmap_event;
7513 if (!atomic_read(&nr_mmap_events))
7516 mmap_event = (struct perf_mmap_event){
7522 .type = PERF_RECORD_MMAP,
7523 .misc = PERF_RECORD_MISC_USER,
7528 .start = vma->vm_start,
7529 .len = vma->vm_end - vma->vm_start,
7530 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7532 /* .maj (attr_mmap2 only) */
7533 /* .min (attr_mmap2 only) */
7534 /* .ino (attr_mmap2 only) */
7535 /* .ino_generation (attr_mmap2 only) */
7536 /* .prot (attr_mmap2 only) */
7537 /* .flags (attr_mmap2 only) */
7540 perf_addr_filters_adjust(vma);
7541 perf_event_mmap_event(&mmap_event);
7544 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7545 unsigned long size, u64 flags)
7547 struct perf_output_handle handle;
7548 struct perf_sample_data sample;
7549 struct perf_aux_event {
7550 struct perf_event_header header;
7556 .type = PERF_RECORD_AUX,
7558 .size = sizeof(rec),
7566 perf_event_header__init_id(&rec.header, &sample, event);
7567 ret = perf_output_begin(&handle, event, rec.header.size);
7572 perf_output_put(&handle, rec);
7573 perf_event__output_id_sample(event, &handle, &sample);
7575 perf_output_end(&handle);
7579 * Lost/dropped samples logging
7581 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7583 struct perf_output_handle handle;
7584 struct perf_sample_data sample;
7588 struct perf_event_header header;
7590 } lost_samples_event = {
7592 .type = PERF_RECORD_LOST_SAMPLES,
7594 .size = sizeof(lost_samples_event),
7599 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7601 ret = perf_output_begin(&handle, event,
7602 lost_samples_event.header.size);
7606 perf_output_put(&handle, lost_samples_event);
7607 perf_event__output_id_sample(event, &handle, &sample);
7608 perf_output_end(&handle);
7612 * context_switch tracking
7615 struct perf_switch_event {
7616 struct task_struct *task;
7617 struct task_struct *next_prev;
7620 struct perf_event_header header;
7626 static int perf_event_switch_match(struct perf_event *event)
7628 return event->attr.context_switch;
7631 static void perf_event_switch_output(struct perf_event *event, void *data)
7633 struct perf_switch_event *se = data;
7634 struct perf_output_handle handle;
7635 struct perf_sample_data sample;
7638 if (!perf_event_switch_match(event))
7641 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7642 if (event->ctx->task) {
7643 se->event_id.header.type = PERF_RECORD_SWITCH;
7644 se->event_id.header.size = sizeof(se->event_id.header);
7646 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7647 se->event_id.header.size = sizeof(se->event_id);
7648 se->event_id.next_prev_pid =
7649 perf_event_pid(event, se->next_prev);
7650 se->event_id.next_prev_tid =
7651 perf_event_tid(event, se->next_prev);
7654 perf_event_header__init_id(&se->event_id.header, &sample, event);
7656 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7660 if (event->ctx->task)
7661 perf_output_put(&handle, se->event_id.header);
7663 perf_output_put(&handle, se->event_id);
7665 perf_event__output_id_sample(event, &handle, &sample);
7667 perf_output_end(&handle);
7670 static void perf_event_switch(struct task_struct *task,
7671 struct task_struct *next_prev, bool sched_in)
7673 struct perf_switch_event switch_event;
7675 /* N.B. caller checks nr_switch_events != 0 */
7677 switch_event = (struct perf_switch_event){
7679 .next_prev = next_prev,
7683 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7686 /* .next_prev_pid */
7687 /* .next_prev_tid */
7691 if (!sched_in && task->state == TASK_RUNNING)
7692 switch_event.event_id.header.misc |=
7693 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7695 perf_iterate_sb(perf_event_switch_output,
7701 * IRQ throttle logging
7704 static void perf_log_throttle(struct perf_event *event, int enable)
7706 struct perf_output_handle handle;
7707 struct perf_sample_data sample;
7711 struct perf_event_header header;
7715 } throttle_event = {
7717 .type = PERF_RECORD_THROTTLE,
7719 .size = sizeof(throttle_event),
7721 .time = perf_event_clock(event),
7722 .id = primary_event_id(event),
7723 .stream_id = event->id,
7727 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7729 perf_event_header__init_id(&throttle_event.header, &sample, event);
7731 ret = perf_output_begin(&handle, event,
7732 throttle_event.header.size);
7736 perf_output_put(&handle, throttle_event);
7737 perf_event__output_id_sample(event, &handle, &sample);
7738 perf_output_end(&handle);
7742 * ksymbol register/unregister tracking
7745 struct perf_ksymbol_event {
7749 struct perf_event_header header;
7757 static int perf_event_ksymbol_match(struct perf_event *event)
7759 return event->attr.ksymbol;
7762 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7764 struct perf_ksymbol_event *ksymbol_event = data;
7765 struct perf_output_handle handle;
7766 struct perf_sample_data sample;
7769 if (!perf_event_ksymbol_match(event))
7772 perf_event_header__init_id(&ksymbol_event->event_id.header,
7774 ret = perf_output_begin(&handle, event,
7775 ksymbol_event->event_id.header.size);
7779 perf_output_put(&handle, ksymbol_event->event_id);
7780 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7781 perf_event__output_id_sample(event, &handle, &sample);
7783 perf_output_end(&handle);
7786 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7789 struct perf_ksymbol_event ksymbol_event;
7790 char name[KSYM_NAME_LEN];
7794 if (!atomic_read(&nr_ksymbol_events))
7797 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7798 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7801 strlcpy(name, sym, KSYM_NAME_LEN);
7802 name_len = strlen(name) + 1;
7803 while (!IS_ALIGNED(name_len, sizeof(u64)))
7804 name[name_len++] = '\0';
7805 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7808 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7810 ksymbol_event = (struct perf_ksymbol_event){
7812 .name_len = name_len,
7815 .type = PERF_RECORD_KSYMBOL,
7816 .size = sizeof(ksymbol_event.event_id) +
7821 .ksym_type = ksym_type,
7826 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7829 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7833 * bpf program load/unload tracking
7836 struct perf_bpf_event {
7837 struct bpf_prog *prog;
7839 struct perf_event_header header;
7843 u8 tag[BPF_TAG_SIZE];
7847 static int perf_event_bpf_match(struct perf_event *event)
7849 return event->attr.bpf_event;
7852 static void perf_event_bpf_output(struct perf_event *event, void *data)
7854 struct perf_bpf_event *bpf_event = data;
7855 struct perf_output_handle handle;
7856 struct perf_sample_data sample;
7859 if (!perf_event_bpf_match(event))
7862 perf_event_header__init_id(&bpf_event->event_id.header,
7864 ret = perf_output_begin(&handle, event,
7865 bpf_event->event_id.header.size);
7869 perf_output_put(&handle, bpf_event->event_id);
7870 perf_event__output_id_sample(event, &handle, &sample);
7872 perf_output_end(&handle);
7875 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
7876 enum perf_bpf_event_type type)
7878 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
7879 char sym[KSYM_NAME_LEN];
7882 if (prog->aux->func_cnt == 0) {
7883 bpf_get_prog_name(prog, sym);
7884 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
7885 (u64)(unsigned long)prog->bpf_func,
7886 prog->jited_len, unregister, sym);
7888 for (i = 0; i < prog->aux->func_cnt; i++) {
7889 struct bpf_prog *subprog = prog->aux->func[i];
7891 bpf_get_prog_name(subprog, sym);
7893 PERF_RECORD_KSYMBOL_TYPE_BPF,
7894 (u64)(unsigned long)subprog->bpf_func,
7895 subprog->jited_len, unregister, sym);
7900 void perf_event_bpf_event(struct bpf_prog *prog,
7901 enum perf_bpf_event_type type,
7904 struct perf_bpf_event bpf_event;
7906 if (type <= PERF_BPF_EVENT_UNKNOWN ||
7907 type >= PERF_BPF_EVENT_MAX)
7911 case PERF_BPF_EVENT_PROG_LOAD:
7912 case PERF_BPF_EVENT_PROG_UNLOAD:
7913 if (atomic_read(&nr_ksymbol_events))
7914 perf_event_bpf_emit_ksymbols(prog, type);
7920 if (!atomic_read(&nr_bpf_events))
7923 bpf_event = (struct perf_bpf_event){
7927 .type = PERF_RECORD_BPF_EVENT,
7928 .size = sizeof(bpf_event.event_id),
7932 .id = prog->aux->id,
7936 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
7938 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
7939 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
7942 void perf_event_itrace_started(struct perf_event *event)
7944 event->attach_state |= PERF_ATTACH_ITRACE;
7947 static void perf_log_itrace_start(struct perf_event *event)
7949 struct perf_output_handle handle;
7950 struct perf_sample_data sample;
7951 struct perf_aux_event {
7952 struct perf_event_header header;
7959 event = event->parent;
7961 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7962 event->attach_state & PERF_ATTACH_ITRACE)
7965 rec.header.type = PERF_RECORD_ITRACE_START;
7966 rec.header.misc = 0;
7967 rec.header.size = sizeof(rec);
7968 rec.pid = perf_event_pid(event, current);
7969 rec.tid = perf_event_tid(event, current);
7971 perf_event_header__init_id(&rec.header, &sample, event);
7972 ret = perf_output_begin(&handle, event, rec.header.size);
7977 perf_output_put(&handle, rec);
7978 perf_event__output_id_sample(event, &handle, &sample);
7980 perf_output_end(&handle);
7984 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7986 struct hw_perf_event *hwc = &event->hw;
7990 seq = __this_cpu_read(perf_throttled_seq);
7991 if (seq != hwc->interrupts_seq) {
7992 hwc->interrupts_seq = seq;
7993 hwc->interrupts = 1;
7996 if (unlikely(throttle
7997 && hwc->interrupts >= max_samples_per_tick)) {
7998 __this_cpu_inc(perf_throttled_count);
7999 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8000 hwc->interrupts = MAX_INTERRUPTS;
8001 perf_log_throttle(event, 0);
8006 if (event->attr.freq) {
8007 u64 now = perf_clock();
8008 s64 delta = now - hwc->freq_time_stamp;
8010 hwc->freq_time_stamp = now;
8012 if (delta > 0 && delta < 2*TICK_NSEC)
8013 perf_adjust_period(event, delta, hwc->last_period, true);
8019 int perf_event_account_interrupt(struct perf_event *event)
8021 return __perf_event_account_interrupt(event, 1);
8025 * Generic event overflow handling, sampling.
8028 static int __perf_event_overflow(struct perf_event *event,
8029 int throttle, struct perf_sample_data *data,
8030 struct pt_regs *regs)
8032 int events = atomic_read(&event->event_limit);
8036 * Non-sampling counters might still use the PMI to fold short
8037 * hardware counters, ignore those.
8039 if (unlikely(!is_sampling_event(event)))
8042 ret = __perf_event_account_interrupt(event, throttle);
8045 * XXX event_limit might not quite work as expected on inherited
8049 event->pending_kill = POLL_IN;
8050 if (events && atomic_dec_and_test(&event->event_limit)) {
8052 event->pending_kill = POLL_HUP;
8054 perf_event_disable_inatomic(event);
8057 READ_ONCE(event->overflow_handler)(event, data, regs);
8059 if (*perf_event_fasync(event) && event->pending_kill) {
8060 event->pending_wakeup = 1;
8061 irq_work_queue(&event->pending);
8067 int perf_event_overflow(struct perf_event *event,
8068 struct perf_sample_data *data,
8069 struct pt_regs *regs)
8071 return __perf_event_overflow(event, 1, data, regs);
8075 * Generic software event infrastructure
8078 struct swevent_htable {
8079 struct swevent_hlist *swevent_hlist;
8080 struct mutex hlist_mutex;
8083 /* Recursion avoidance in each contexts */
8084 int recursion[PERF_NR_CONTEXTS];
8087 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8090 * We directly increment event->count and keep a second value in
8091 * event->hw.period_left to count intervals. This period event
8092 * is kept in the range [-sample_period, 0] so that we can use the
8096 u64 perf_swevent_set_period(struct perf_event *event)
8098 struct hw_perf_event *hwc = &event->hw;
8099 u64 period = hwc->last_period;
8103 hwc->last_period = hwc->sample_period;
8106 old = val = local64_read(&hwc->period_left);
8110 nr = div64_u64(period + val, period);
8111 offset = nr * period;
8113 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8119 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8120 struct perf_sample_data *data,
8121 struct pt_regs *regs)
8123 struct hw_perf_event *hwc = &event->hw;
8127 overflow = perf_swevent_set_period(event);
8129 if (hwc->interrupts == MAX_INTERRUPTS)
8132 for (; overflow; overflow--) {
8133 if (__perf_event_overflow(event, throttle,
8136 * We inhibit the overflow from happening when
8137 * hwc->interrupts == MAX_INTERRUPTS.
8145 static void perf_swevent_event(struct perf_event *event, u64 nr,
8146 struct perf_sample_data *data,
8147 struct pt_regs *regs)
8149 struct hw_perf_event *hwc = &event->hw;
8151 local64_add(nr, &event->count);
8156 if (!is_sampling_event(event))
8159 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8161 return perf_swevent_overflow(event, 1, data, regs);
8163 data->period = event->hw.last_period;
8165 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8166 return perf_swevent_overflow(event, 1, data, regs);
8168 if (local64_add_negative(nr, &hwc->period_left))
8171 perf_swevent_overflow(event, 0, data, regs);
8174 static int perf_exclude_event(struct perf_event *event,
8175 struct pt_regs *regs)
8177 if (event->hw.state & PERF_HES_STOPPED)
8181 if (event->attr.exclude_user && user_mode(regs))
8184 if (event->attr.exclude_kernel && !user_mode(regs))
8191 static int perf_swevent_match(struct perf_event *event,
8192 enum perf_type_id type,
8194 struct perf_sample_data *data,
8195 struct pt_regs *regs)
8197 if (event->attr.type != type)
8200 if (event->attr.config != event_id)
8203 if (perf_exclude_event(event, regs))
8209 static inline u64 swevent_hash(u64 type, u32 event_id)
8211 u64 val = event_id | (type << 32);
8213 return hash_64(val, SWEVENT_HLIST_BITS);
8216 static inline struct hlist_head *
8217 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8219 u64 hash = swevent_hash(type, event_id);
8221 return &hlist->heads[hash];
8224 /* For the read side: events when they trigger */
8225 static inline struct hlist_head *
8226 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8228 struct swevent_hlist *hlist;
8230 hlist = rcu_dereference(swhash->swevent_hlist);
8234 return __find_swevent_head(hlist, type, event_id);
8237 /* For the event head insertion and removal in the hlist */
8238 static inline struct hlist_head *
8239 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8241 struct swevent_hlist *hlist;
8242 u32 event_id = event->attr.config;
8243 u64 type = event->attr.type;
8246 * Event scheduling is always serialized against hlist allocation
8247 * and release. Which makes the protected version suitable here.
8248 * The context lock guarantees that.
8250 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8251 lockdep_is_held(&event->ctx->lock));
8255 return __find_swevent_head(hlist, type, event_id);
8258 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8260 struct perf_sample_data *data,
8261 struct pt_regs *regs)
8263 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8264 struct perf_event *event;
8265 struct hlist_head *head;
8268 head = find_swevent_head_rcu(swhash, type, event_id);
8272 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8273 if (perf_swevent_match(event, type, event_id, data, regs))
8274 perf_swevent_event(event, nr, data, regs);
8280 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8282 int perf_swevent_get_recursion_context(void)
8284 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8286 return get_recursion_context(swhash->recursion);
8288 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8290 void perf_swevent_put_recursion_context(int rctx)
8292 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8294 put_recursion_context(swhash->recursion, rctx);
8297 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8299 struct perf_sample_data data;
8301 if (WARN_ON_ONCE(!regs))
8304 perf_sample_data_init(&data, addr, 0);
8305 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8308 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8312 preempt_disable_notrace();
8313 rctx = perf_swevent_get_recursion_context();
8314 if (unlikely(rctx < 0))
8317 ___perf_sw_event(event_id, nr, regs, addr);
8319 perf_swevent_put_recursion_context(rctx);
8321 preempt_enable_notrace();
8324 static void perf_swevent_read(struct perf_event *event)
8328 static int perf_swevent_add(struct perf_event *event, int flags)
8330 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8331 struct hw_perf_event *hwc = &event->hw;
8332 struct hlist_head *head;
8334 if (is_sampling_event(event)) {
8335 hwc->last_period = hwc->sample_period;
8336 perf_swevent_set_period(event);
8339 hwc->state = !(flags & PERF_EF_START);
8341 head = find_swevent_head(swhash, event);
8342 if (WARN_ON_ONCE(!head))
8345 hlist_add_head_rcu(&event->hlist_entry, head);
8346 perf_event_update_userpage(event);
8351 static void perf_swevent_del(struct perf_event *event, int flags)
8353 hlist_del_rcu(&event->hlist_entry);
8356 static void perf_swevent_start(struct perf_event *event, int flags)
8358 event->hw.state = 0;
8361 static void perf_swevent_stop(struct perf_event *event, int flags)
8363 event->hw.state = PERF_HES_STOPPED;
8366 /* Deref the hlist from the update side */
8367 static inline struct swevent_hlist *
8368 swevent_hlist_deref(struct swevent_htable *swhash)
8370 return rcu_dereference_protected(swhash->swevent_hlist,
8371 lockdep_is_held(&swhash->hlist_mutex));
8374 static void swevent_hlist_release(struct swevent_htable *swhash)
8376 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8381 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8382 kfree_rcu(hlist, rcu_head);
8385 static void swevent_hlist_put_cpu(int cpu)
8387 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8389 mutex_lock(&swhash->hlist_mutex);
8391 if (!--swhash->hlist_refcount)
8392 swevent_hlist_release(swhash);
8394 mutex_unlock(&swhash->hlist_mutex);
8397 static void swevent_hlist_put(void)
8401 for_each_possible_cpu(cpu)
8402 swevent_hlist_put_cpu(cpu);
8405 static int swevent_hlist_get_cpu(int cpu)
8407 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8410 mutex_lock(&swhash->hlist_mutex);
8411 if (!swevent_hlist_deref(swhash) &&
8412 cpumask_test_cpu(cpu, perf_online_mask)) {
8413 struct swevent_hlist *hlist;
8415 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8420 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8422 swhash->hlist_refcount++;
8424 mutex_unlock(&swhash->hlist_mutex);
8429 static int swevent_hlist_get(void)
8431 int err, cpu, failed_cpu;
8433 mutex_lock(&pmus_lock);
8434 for_each_possible_cpu(cpu) {
8435 err = swevent_hlist_get_cpu(cpu);
8441 mutex_unlock(&pmus_lock);
8444 for_each_possible_cpu(cpu) {
8445 if (cpu == failed_cpu)
8447 swevent_hlist_put_cpu(cpu);
8449 mutex_unlock(&pmus_lock);
8453 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8455 static void sw_perf_event_destroy(struct perf_event *event)
8457 u64 event_id = event->attr.config;
8459 WARN_ON(event->parent);
8461 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8462 swevent_hlist_put();
8465 static int perf_swevent_init(struct perf_event *event)
8467 u64 event_id = event->attr.config;
8469 if (event->attr.type != PERF_TYPE_SOFTWARE)
8473 * no branch sampling for software events
8475 if (has_branch_stack(event))
8479 case PERF_COUNT_SW_CPU_CLOCK:
8480 case PERF_COUNT_SW_TASK_CLOCK:
8487 if (event_id >= PERF_COUNT_SW_MAX)
8490 if (!event->parent) {
8493 err = swevent_hlist_get();
8497 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8498 event->destroy = sw_perf_event_destroy;
8504 static struct pmu perf_swevent = {
8505 .task_ctx_nr = perf_sw_context,
8507 .capabilities = PERF_PMU_CAP_NO_NMI,
8509 .event_init = perf_swevent_init,
8510 .add = perf_swevent_add,
8511 .del = perf_swevent_del,
8512 .start = perf_swevent_start,
8513 .stop = perf_swevent_stop,
8514 .read = perf_swevent_read,
8517 #ifdef CONFIG_EVENT_TRACING
8519 static int perf_tp_filter_match(struct perf_event *event,
8520 struct perf_sample_data *data)
8522 void *record = data->raw->frag.data;
8524 /* only top level events have filters set */
8526 event = event->parent;
8528 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8533 static int perf_tp_event_match(struct perf_event *event,
8534 struct perf_sample_data *data,
8535 struct pt_regs *regs)
8537 if (event->hw.state & PERF_HES_STOPPED)
8540 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8542 if (event->attr.exclude_kernel && !user_mode(regs))
8545 if (!perf_tp_filter_match(event, data))
8551 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8552 struct trace_event_call *call, u64 count,
8553 struct pt_regs *regs, struct hlist_head *head,
8554 struct task_struct *task)
8556 if (bpf_prog_array_valid(call)) {
8557 *(struct pt_regs **)raw_data = regs;
8558 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8559 perf_swevent_put_recursion_context(rctx);
8563 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8566 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8568 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8569 struct pt_regs *regs, struct hlist_head *head, int rctx,
8570 struct task_struct *task)
8572 struct perf_sample_data data;
8573 struct perf_event *event;
8575 struct perf_raw_record raw = {
8582 perf_sample_data_init(&data, 0, 0);
8585 perf_trace_buf_update(record, event_type);
8587 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8588 if (perf_tp_event_match(event, &data, regs))
8589 perf_swevent_event(event, count, &data, regs);
8593 * If we got specified a target task, also iterate its context and
8594 * deliver this event there too.
8596 if (task && task != current) {
8597 struct perf_event_context *ctx;
8598 struct trace_entry *entry = record;
8601 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8605 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8606 if (event->cpu != smp_processor_id())
8608 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8610 if (event->attr.config != entry->type)
8612 if (perf_tp_event_match(event, &data, regs))
8613 perf_swevent_event(event, count, &data, regs);
8619 perf_swevent_put_recursion_context(rctx);
8621 EXPORT_SYMBOL_GPL(perf_tp_event);
8623 static void tp_perf_event_destroy(struct perf_event *event)
8625 perf_trace_destroy(event);
8628 static int perf_tp_event_init(struct perf_event *event)
8632 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8636 * no branch sampling for tracepoint events
8638 if (has_branch_stack(event))
8641 err = perf_trace_init(event);
8645 event->destroy = tp_perf_event_destroy;
8650 static struct pmu perf_tracepoint = {
8651 .task_ctx_nr = perf_sw_context,
8653 .event_init = perf_tp_event_init,
8654 .add = perf_trace_add,
8655 .del = perf_trace_del,
8656 .start = perf_swevent_start,
8657 .stop = perf_swevent_stop,
8658 .read = perf_swevent_read,
8661 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8663 * Flags in config, used by dynamic PMU kprobe and uprobe
8664 * The flags should match following PMU_FORMAT_ATTR().
8666 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8667 * if not set, create kprobe/uprobe
8669 * The following values specify a reference counter (or semaphore in the
8670 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8671 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8673 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8674 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8676 enum perf_probe_config {
8677 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8678 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8679 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8682 PMU_FORMAT_ATTR(retprobe, "config:0");
8685 #ifdef CONFIG_KPROBE_EVENTS
8686 static struct attribute *kprobe_attrs[] = {
8687 &format_attr_retprobe.attr,
8691 static struct attribute_group kprobe_format_group = {
8693 .attrs = kprobe_attrs,
8696 static const struct attribute_group *kprobe_attr_groups[] = {
8697 &kprobe_format_group,
8701 static int perf_kprobe_event_init(struct perf_event *event);
8702 static struct pmu perf_kprobe = {
8703 .task_ctx_nr = perf_sw_context,
8704 .event_init = perf_kprobe_event_init,
8705 .add = perf_trace_add,
8706 .del = perf_trace_del,
8707 .start = perf_swevent_start,
8708 .stop = perf_swevent_stop,
8709 .read = perf_swevent_read,
8710 .attr_groups = kprobe_attr_groups,
8713 static int perf_kprobe_event_init(struct perf_event *event)
8718 if (event->attr.type != perf_kprobe.type)
8721 if (!capable(CAP_SYS_ADMIN))
8725 * no branch sampling for probe events
8727 if (has_branch_stack(event))
8730 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8731 err = perf_kprobe_init(event, is_retprobe);
8735 event->destroy = perf_kprobe_destroy;
8739 #endif /* CONFIG_KPROBE_EVENTS */
8741 #ifdef CONFIG_UPROBE_EVENTS
8742 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8744 static struct attribute *uprobe_attrs[] = {
8745 &format_attr_retprobe.attr,
8746 &format_attr_ref_ctr_offset.attr,
8750 static struct attribute_group uprobe_format_group = {
8752 .attrs = uprobe_attrs,
8755 static const struct attribute_group *uprobe_attr_groups[] = {
8756 &uprobe_format_group,
8760 static int perf_uprobe_event_init(struct perf_event *event);
8761 static struct pmu perf_uprobe = {
8762 .task_ctx_nr = perf_sw_context,
8763 .event_init = perf_uprobe_event_init,
8764 .add = perf_trace_add,
8765 .del = perf_trace_del,
8766 .start = perf_swevent_start,
8767 .stop = perf_swevent_stop,
8768 .read = perf_swevent_read,
8769 .attr_groups = uprobe_attr_groups,
8772 static int perf_uprobe_event_init(struct perf_event *event)
8775 unsigned long ref_ctr_offset;
8778 if (event->attr.type != perf_uprobe.type)
8781 if (!capable(CAP_SYS_ADMIN))
8785 * no branch sampling for probe events
8787 if (has_branch_stack(event))
8790 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8791 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8792 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8796 event->destroy = perf_uprobe_destroy;
8800 #endif /* CONFIG_UPROBE_EVENTS */
8802 static inline void perf_tp_register(void)
8804 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8805 #ifdef CONFIG_KPROBE_EVENTS
8806 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8808 #ifdef CONFIG_UPROBE_EVENTS
8809 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8813 static void perf_event_free_filter(struct perf_event *event)
8815 ftrace_profile_free_filter(event);
8818 #ifdef CONFIG_BPF_SYSCALL
8819 static void bpf_overflow_handler(struct perf_event *event,
8820 struct perf_sample_data *data,
8821 struct pt_regs *regs)
8823 struct bpf_perf_event_data_kern ctx = {
8829 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8831 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8834 ret = BPF_PROG_RUN(event->prog, &ctx);
8837 __this_cpu_dec(bpf_prog_active);
8842 event->orig_overflow_handler(event, data, regs);
8845 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8847 struct bpf_prog *prog;
8849 if (event->overflow_handler_context)
8850 /* hw breakpoint or kernel counter */
8856 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8858 return PTR_ERR(prog);
8861 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8862 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8866 static void perf_event_free_bpf_handler(struct perf_event *event)
8868 struct bpf_prog *prog = event->prog;
8873 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8878 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8882 static void perf_event_free_bpf_handler(struct perf_event *event)
8888 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8889 * with perf_event_open()
8891 static inline bool perf_event_is_tracing(struct perf_event *event)
8893 if (event->pmu == &perf_tracepoint)
8895 #ifdef CONFIG_KPROBE_EVENTS
8896 if (event->pmu == &perf_kprobe)
8899 #ifdef CONFIG_UPROBE_EVENTS
8900 if (event->pmu == &perf_uprobe)
8906 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8908 bool is_kprobe, is_tracepoint, is_syscall_tp;
8909 struct bpf_prog *prog;
8912 if (!perf_event_is_tracing(event))
8913 return perf_event_set_bpf_handler(event, prog_fd);
8915 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8916 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8917 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8918 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8919 /* bpf programs can only be attached to u/kprobe or tracepoint */
8922 prog = bpf_prog_get(prog_fd);
8924 return PTR_ERR(prog);
8926 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8927 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8928 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8929 /* valid fd, but invalid bpf program type */
8934 /* Kprobe override only works for kprobes, not uprobes. */
8935 if (prog->kprobe_override &&
8936 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8941 if (is_tracepoint || is_syscall_tp) {
8942 int off = trace_event_get_offsets(event->tp_event);
8944 if (prog->aux->max_ctx_offset > off) {
8950 ret = perf_event_attach_bpf_prog(event, prog);
8956 static void perf_event_free_bpf_prog(struct perf_event *event)
8958 if (!perf_event_is_tracing(event)) {
8959 perf_event_free_bpf_handler(event);
8962 perf_event_detach_bpf_prog(event);
8967 static inline void perf_tp_register(void)
8971 static void perf_event_free_filter(struct perf_event *event)
8975 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8980 static void perf_event_free_bpf_prog(struct perf_event *event)
8983 #endif /* CONFIG_EVENT_TRACING */
8985 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8986 void perf_bp_event(struct perf_event *bp, void *data)
8988 struct perf_sample_data sample;
8989 struct pt_regs *regs = data;
8991 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8993 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8994 perf_swevent_event(bp, 1, &sample, regs);
8999 * Allocate a new address filter
9001 static struct perf_addr_filter *
9002 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9004 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9005 struct perf_addr_filter *filter;
9007 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9011 INIT_LIST_HEAD(&filter->entry);
9012 list_add_tail(&filter->entry, filters);
9017 static void free_filters_list(struct list_head *filters)
9019 struct perf_addr_filter *filter, *iter;
9021 list_for_each_entry_safe(filter, iter, filters, entry) {
9022 path_put(&filter->path);
9023 list_del(&filter->entry);
9029 * Free existing address filters and optionally install new ones
9031 static void perf_addr_filters_splice(struct perf_event *event,
9032 struct list_head *head)
9034 unsigned long flags;
9037 if (!has_addr_filter(event))
9040 /* don't bother with children, they don't have their own filters */
9044 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9046 list_splice_init(&event->addr_filters.list, &list);
9048 list_splice(head, &event->addr_filters.list);
9050 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9052 free_filters_list(&list);
9056 * Scan through mm's vmas and see if one of them matches the
9057 * @filter; if so, adjust filter's address range.
9058 * Called with mm::mmap_sem down for reading.
9060 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9061 struct mm_struct *mm,
9062 struct perf_addr_filter_range *fr)
9064 struct vm_area_struct *vma;
9066 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9070 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9076 * Update event's address range filters based on the
9077 * task's existing mappings, if any.
9079 static void perf_event_addr_filters_apply(struct perf_event *event)
9081 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9082 struct task_struct *task = READ_ONCE(event->ctx->task);
9083 struct perf_addr_filter *filter;
9084 struct mm_struct *mm = NULL;
9085 unsigned int count = 0;
9086 unsigned long flags;
9089 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9090 * will stop on the parent's child_mutex that our caller is also holding
9092 if (task == TASK_TOMBSTONE)
9095 if (ifh->nr_file_filters) {
9096 mm = get_task_mm(event->ctx->task);
9100 down_read(&mm->mmap_sem);
9103 raw_spin_lock_irqsave(&ifh->lock, flags);
9104 list_for_each_entry(filter, &ifh->list, entry) {
9105 if (filter->path.dentry) {
9107 * Adjust base offset if the filter is associated to a
9108 * binary that needs to be mapped:
9110 event->addr_filter_ranges[count].start = 0;
9111 event->addr_filter_ranges[count].size = 0;
9113 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9115 event->addr_filter_ranges[count].start = filter->offset;
9116 event->addr_filter_ranges[count].size = filter->size;
9122 event->addr_filters_gen++;
9123 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9125 if (ifh->nr_file_filters) {
9126 up_read(&mm->mmap_sem);
9132 perf_event_stop(event, 1);
9136 * Address range filtering: limiting the data to certain
9137 * instruction address ranges. Filters are ioctl()ed to us from
9138 * userspace as ascii strings.
9140 * Filter string format:
9143 * where ACTION is one of the
9144 * * "filter": limit the trace to this region
9145 * * "start": start tracing from this address
9146 * * "stop": stop tracing at this address/region;
9148 * * for kernel addresses: <start address>[/<size>]
9149 * * for object files: <start address>[/<size>]@</path/to/object/file>
9151 * if <size> is not specified or is zero, the range is treated as a single
9152 * address; not valid for ACTION=="filter".
9166 IF_STATE_ACTION = 0,
9171 static const match_table_t if_tokens = {
9172 { IF_ACT_FILTER, "filter" },
9173 { IF_ACT_START, "start" },
9174 { IF_ACT_STOP, "stop" },
9175 { IF_SRC_FILE, "%u/%u@%s" },
9176 { IF_SRC_KERNEL, "%u/%u" },
9177 { IF_SRC_FILEADDR, "%u@%s" },
9178 { IF_SRC_KERNELADDR, "%u" },
9179 { IF_ACT_NONE, NULL },
9183 * Address filter string parser
9186 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9187 struct list_head *filters)
9189 struct perf_addr_filter *filter = NULL;
9190 char *start, *orig, *filename = NULL;
9191 substring_t args[MAX_OPT_ARGS];
9192 int state = IF_STATE_ACTION, token;
9193 unsigned int kernel = 0;
9196 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9200 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9201 static const enum perf_addr_filter_action_t actions[] = {
9202 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9203 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9204 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9211 /* filter definition begins */
9212 if (state == IF_STATE_ACTION) {
9213 filter = perf_addr_filter_new(event, filters);
9218 token = match_token(start, if_tokens, args);
9223 if (state != IF_STATE_ACTION)
9226 filter->action = actions[token];
9227 state = IF_STATE_SOURCE;
9230 case IF_SRC_KERNELADDR:
9235 case IF_SRC_FILEADDR:
9237 if (state != IF_STATE_SOURCE)
9241 ret = kstrtoul(args[0].from, 0, &filter->offset);
9245 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9247 ret = kstrtoul(args[1].from, 0, &filter->size);
9252 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9253 int fpos = token == IF_SRC_FILE ? 2 : 1;
9255 filename = match_strdup(&args[fpos]);
9262 state = IF_STATE_END;
9270 * Filter definition is fully parsed, validate and install it.
9271 * Make sure that it doesn't contradict itself or the event's
9274 if (state == IF_STATE_END) {
9276 if (kernel && event->attr.exclude_kernel)
9280 * ACTION "filter" must have a non-zero length region
9283 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9292 * For now, we only support file-based filters
9293 * in per-task events; doing so for CPU-wide
9294 * events requires additional context switching
9295 * trickery, since same object code will be
9296 * mapped at different virtual addresses in
9297 * different processes.
9300 if (!event->ctx->task)
9301 goto fail_free_name;
9303 /* look up the path and grab its inode */
9304 ret = kern_path(filename, LOOKUP_FOLLOW,
9307 goto fail_free_name;
9313 if (!filter->path.dentry ||
9314 !S_ISREG(d_inode(filter->path.dentry)
9318 event->addr_filters.nr_file_filters++;
9321 /* ready to consume more filters */
9322 state = IF_STATE_ACTION;
9327 if (state != IF_STATE_ACTION)
9337 free_filters_list(filters);
9344 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9350 * Since this is called in perf_ioctl() path, we're already holding
9353 lockdep_assert_held(&event->ctx->mutex);
9355 if (WARN_ON_ONCE(event->parent))
9358 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9360 goto fail_clear_files;
9362 ret = event->pmu->addr_filters_validate(&filters);
9364 goto fail_free_filters;
9366 /* remove existing filters, if any */
9367 perf_addr_filters_splice(event, &filters);
9369 /* install new filters */
9370 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9375 free_filters_list(&filters);
9378 event->addr_filters.nr_file_filters = 0;
9383 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9388 filter_str = strndup_user(arg, PAGE_SIZE);
9389 if (IS_ERR(filter_str))
9390 return PTR_ERR(filter_str);
9392 #ifdef CONFIG_EVENT_TRACING
9393 if (perf_event_is_tracing(event)) {
9394 struct perf_event_context *ctx = event->ctx;
9397 * Beware, here be dragons!!
9399 * the tracepoint muck will deadlock against ctx->mutex, but
9400 * the tracepoint stuff does not actually need it. So
9401 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9402 * already have a reference on ctx.
9404 * This can result in event getting moved to a different ctx,
9405 * but that does not affect the tracepoint state.
9407 mutex_unlock(&ctx->mutex);
9408 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9409 mutex_lock(&ctx->mutex);
9412 if (has_addr_filter(event))
9413 ret = perf_event_set_addr_filter(event, filter_str);
9420 * hrtimer based swevent callback
9423 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9425 enum hrtimer_restart ret = HRTIMER_RESTART;
9426 struct perf_sample_data data;
9427 struct pt_regs *regs;
9428 struct perf_event *event;
9431 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9433 if (event->state != PERF_EVENT_STATE_ACTIVE)
9434 return HRTIMER_NORESTART;
9436 event->pmu->read(event);
9438 perf_sample_data_init(&data, 0, event->hw.last_period);
9439 regs = get_irq_regs();
9441 if (regs && !perf_exclude_event(event, regs)) {
9442 if (!(event->attr.exclude_idle && is_idle_task(current)))
9443 if (__perf_event_overflow(event, 1, &data, regs))
9444 ret = HRTIMER_NORESTART;
9447 period = max_t(u64, 10000, event->hw.sample_period);
9448 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9453 static void perf_swevent_start_hrtimer(struct perf_event *event)
9455 struct hw_perf_event *hwc = &event->hw;
9458 if (!is_sampling_event(event))
9461 period = local64_read(&hwc->period_left);
9466 local64_set(&hwc->period_left, 0);
9468 period = max_t(u64, 10000, hwc->sample_period);
9470 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9471 HRTIMER_MODE_REL_PINNED);
9474 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9476 struct hw_perf_event *hwc = &event->hw;
9478 if (is_sampling_event(event)) {
9479 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9480 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9482 hrtimer_cancel(&hwc->hrtimer);
9486 static void perf_swevent_init_hrtimer(struct perf_event *event)
9488 struct hw_perf_event *hwc = &event->hw;
9490 if (!is_sampling_event(event))
9493 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9494 hwc->hrtimer.function = perf_swevent_hrtimer;
9497 * Since hrtimers have a fixed rate, we can do a static freq->period
9498 * mapping and avoid the whole period adjust feedback stuff.
9500 if (event->attr.freq) {
9501 long freq = event->attr.sample_freq;
9503 event->attr.sample_period = NSEC_PER_SEC / freq;
9504 hwc->sample_period = event->attr.sample_period;
9505 local64_set(&hwc->period_left, hwc->sample_period);
9506 hwc->last_period = hwc->sample_period;
9507 event->attr.freq = 0;
9512 * Software event: cpu wall time clock
9515 static void cpu_clock_event_update(struct perf_event *event)
9520 now = local_clock();
9521 prev = local64_xchg(&event->hw.prev_count, now);
9522 local64_add(now - prev, &event->count);
9525 static void cpu_clock_event_start(struct perf_event *event, int flags)
9527 local64_set(&event->hw.prev_count, local_clock());
9528 perf_swevent_start_hrtimer(event);
9531 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9533 perf_swevent_cancel_hrtimer(event);
9534 cpu_clock_event_update(event);
9537 static int cpu_clock_event_add(struct perf_event *event, int flags)
9539 if (flags & PERF_EF_START)
9540 cpu_clock_event_start(event, flags);
9541 perf_event_update_userpage(event);
9546 static void cpu_clock_event_del(struct perf_event *event, int flags)
9548 cpu_clock_event_stop(event, flags);
9551 static void cpu_clock_event_read(struct perf_event *event)
9553 cpu_clock_event_update(event);
9556 static int cpu_clock_event_init(struct perf_event *event)
9558 if (event->attr.type != PERF_TYPE_SOFTWARE)
9561 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9565 * no branch sampling for software events
9567 if (has_branch_stack(event))
9570 perf_swevent_init_hrtimer(event);
9575 static struct pmu perf_cpu_clock = {
9576 .task_ctx_nr = perf_sw_context,
9578 .capabilities = PERF_PMU_CAP_NO_NMI,
9580 .event_init = cpu_clock_event_init,
9581 .add = cpu_clock_event_add,
9582 .del = cpu_clock_event_del,
9583 .start = cpu_clock_event_start,
9584 .stop = cpu_clock_event_stop,
9585 .read = cpu_clock_event_read,
9589 * Software event: task time clock
9592 static void task_clock_event_update(struct perf_event *event, u64 now)
9597 prev = local64_xchg(&event->hw.prev_count, now);
9599 local64_add(delta, &event->count);
9602 static void task_clock_event_start(struct perf_event *event, int flags)
9604 local64_set(&event->hw.prev_count, event->ctx->time);
9605 perf_swevent_start_hrtimer(event);
9608 static void task_clock_event_stop(struct perf_event *event, int flags)
9610 perf_swevent_cancel_hrtimer(event);
9611 task_clock_event_update(event, event->ctx->time);
9614 static int task_clock_event_add(struct perf_event *event, int flags)
9616 if (flags & PERF_EF_START)
9617 task_clock_event_start(event, flags);
9618 perf_event_update_userpage(event);
9623 static void task_clock_event_del(struct perf_event *event, int flags)
9625 task_clock_event_stop(event, PERF_EF_UPDATE);
9628 static void task_clock_event_read(struct perf_event *event)
9630 u64 now = perf_clock();
9631 u64 delta = now - event->ctx->timestamp;
9632 u64 time = event->ctx->time + delta;
9634 task_clock_event_update(event, time);
9637 static int task_clock_event_init(struct perf_event *event)
9639 if (event->attr.type != PERF_TYPE_SOFTWARE)
9642 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9646 * no branch sampling for software events
9648 if (has_branch_stack(event))
9651 perf_swevent_init_hrtimer(event);
9656 static struct pmu perf_task_clock = {
9657 .task_ctx_nr = perf_sw_context,
9659 .capabilities = PERF_PMU_CAP_NO_NMI,
9661 .event_init = task_clock_event_init,
9662 .add = task_clock_event_add,
9663 .del = task_clock_event_del,
9664 .start = task_clock_event_start,
9665 .stop = task_clock_event_stop,
9666 .read = task_clock_event_read,
9669 static void perf_pmu_nop_void(struct pmu *pmu)
9673 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9677 static int perf_pmu_nop_int(struct pmu *pmu)
9682 static int perf_event_nop_int(struct perf_event *event, u64 value)
9687 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9689 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9691 __this_cpu_write(nop_txn_flags, flags);
9693 if (flags & ~PERF_PMU_TXN_ADD)
9696 perf_pmu_disable(pmu);
9699 static int perf_pmu_commit_txn(struct pmu *pmu)
9701 unsigned int flags = __this_cpu_read(nop_txn_flags);
9703 __this_cpu_write(nop_txn_flags, 0);
9705 if (flags & ~PERF_PMU_TXN_ADD)
9708 perf_pmu_enable(pmu);
9712 static void perf_pmu_cancel_txn(struct pmu *pmu)
9714 unsigned int flags = __this_cpu_read(nop_txn_flags);
9716 __this_cpu_write(nop_txn_flags, 0);
9718 if (flags & ~PERF_PMU_TXN_ADD)
9721 perf_pmu_enable(pmu);
9724 static int perf_event_idx_default(struct perf_event *event)
9730 * Ensures all contexts with the same task_ctx_nr have the same
9731 * pmu_cpu_context too.
9733 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9740 list_for_each_entry(pmu, &pmus, entry) {
9741 if (pmu->task_ctx_nr == ctxn)
9742 return pmu->pmu_cpu_context;
9748 static void free_pmu_context(struct pmu *pmu)
9751 * Static contexts such as perf_sw_context have a global lifetime
9752 * and may be shared between different PMUs. Avoid freeing them
9753 * when a single PMU is going away.
9755 if (pmu->task_ctx_nr > perf_invalid_context)
9758 free_percpu(pmu->pmu_cpu_context);
9762 * Let userspace know that this PMU supports address range filtering:
9764 static ssize_t nr_addr_filters_show(struct device *dev,
9765 struct device_attribute *attr,
9768 struct pmu *pmu = dev_get_drvdata(dev);
9770 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9772 DEVICE_ATTR_RO(nr_addr_filters);
9774 static struct idr pmu_idr;
9777 type_show(struct device *dev, struct device_attribute *attr, char *page)
9779 struct pmu *pmu = dev_get_drvdata(dev);
9781 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9783 static DEVICE_ATTR_RO(type);
9786 perf_event_mux_interval_ms_show(struct device *dev,
9787 struct device_attribute *attr,
9790 struct pmu *pmu = dev_get_drvdata(dev);
9792 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9795 static DEFINE_MUTEX(mux_interval_mutex);
9798 perf_event_mux_interval_ms_store(struct device *dev,
9799 struct device_attribute *attr,
9800 const char *buf, size_t count)
9802 struct pmu *pmu = dev_get_drvdata(dev);
9803 int timer, cpu, ret;
9805 ret = kstrtoint(buf, 0, &timer);
9812 /* same value, noting to do */
9813 if (timer == pmu->hrtimer_interval_ms)
9816 mutex_lock(&mux_interval_mutex);
9817 pmu->hrtimer_interval_ms = timer;
9819 /* update all cpuctx for this PMU */
9821 for_each_online_cpu(cpu) {
9822 struct perf_cpu_context *cpuctx;
9823 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9824 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9826 cpu_function_call(cpu,
9827 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9830 mutex_unlock(&mux_interval_mutex);
9834 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9836 static struct attribute *pmu_dev_attrs[] = {
9837 &dev_attr_type.attr,
9838 &dev_attr_perf_event_mux_interval_ms.attr,
9841 ATTRIBUTE_GROUPS(pmu_dev);
9843 static int pmu_bus_running;
9844 static struct bus_type pmu_bus = {
9845 .name = "event_source",
9846 .dev_groups = pmu_dev_groups,
9849 static void pmu_dev_release(struct device *dev)
9854 static int pmu_dev_alloc(struct pmu *pmu)
9858 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9862 pmu->dev->groups = pmu->attr_groups;
9863 device_initialize(pmu->dev);
9864 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9868 dev_set_drvdata(pmu->dev, pmu);
9869 pmu->dev->bus = &pmu_bus;
9870 pmu->dev->release = pmu_dev_release;
9871 ret = device_add(pmu->dev);
9875 /* For PMUs with address filters, throw in an extra attribute: */
9876 if (pmu->nr_addr_filters)
9877 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9882 if (pmu->attr_update)
9883 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
9892 device_del(pmu->dev);
9895 put_device(pmu->dev);
9899 static struct lock_class_key cpuctx_mutex;
9900 static struct lock_class_key cpuctx_lock;
9902 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9906 mutex_lock(&pmus_lock);
9908 pmu->pmu_disable_count = alloc_percpu(int);
9909 if (!pmu->pmu_disable_count)
9918 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9926 if (pmu_bus_running) {
9927 ret = pmu_dev_alloc(pmu);
9933 if (pmu->task_ctx_nr == perf_hw_context) {
9934 static int hw_context_taken = 0;
9937 * Other than systems with heterogeneous CPUs, it never makes
9938 * sense for two PMUs to share perf_hw_context. PMUs which are
9939 * uncore must use perf_invalid_context.
9941 if (WARN_ON_ONCE(hw_context_taken &&
9942 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9943 pmu->task_ctx_nr = perf_invalid_context;
9945 hw_context_taken = 1;
9948 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9949 if (pmu->pmu_cpu_context)
9950 goto got_cpu_context;
9953 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9954 if (!pmu->pmu_cpu_context)
9957 for_each_possible_cpu(cpu) {
9958 struct perf_cpu_context *cpuctx;
9960 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9961 __perf_event_init_context(&cpuctx->ctx);
9962 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9963 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9964 cpuctx->ctx.pmu = pmu;
9965 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9967 __perf_mux_hrtimer_init(cpuctx, cpu);
9971 if (!pmu->start_txn) {
9972 if (pmu->pmu_enable) {
9974 * If we have pmu_enable/pmu_disable calls, install
9975 * transaction stubs that use that to try and batch
9976 * hardware accesses.
9978 pmu->start_txn = perf_pmu_start_txn;
9979 pmu->commit_txn = perf_pmu_commit_txn;
9980 pmu->cancel_txn = perf_pmu_cancel_txn;
9982 pmu->start_txn = perf_pmu_nop_txn;
9983 pmu->commit_txn = perf_pmu_nop_int;
9984 pmu->cancel_txn = perf_pmu_nop_void;
9988 if (!pmu->pmu_enable) {
9989 pmu->pmu_enable = perf_pmu_nop_void;
9990 pmu->pmu_disable = perf_pmu_nop_void;
9993 if (!pmu->check_period)
9994 pmu->check_period = perf_event_nop_int;
9996 if (!pmu->event_idx)
9997 pmu->event_idx = perf_event_idx_default;
9999 list_add_rcu(&pmu->entry, &pmus);
10000 atomic_set(&pmu->exclusive_cnt, 0);
10003 mutex_unlock(&pmus_lock);
10008 device_del(pmu->dev);
10009 put_device(pmu->dev);
10012 if (pmu->type >= PERF_TYPE_MAX)
10013 idr_remove(&pmu_idr, pmu->type);
10016 free_percpu(pmu->pmu_disable_count);
10019 EXPORT_SYMBOL_GPL(perf_pmu_register);
10021 void perf_pmu_unregister(struct pmu *pmu)
10023 mutex_lock(&pmus_lock);
10024 list_del_rcu(&pmu->entry);
10027 * We dereference the pmu list under both SRCU and regular RCU, so
10028 * synchronize against both of those.
10030 synchronize_srcu(&pmus_srcu);
10033 free_percpu(pmu->pmu_disable_count);
10034 if (pmu->type >= PERF_TYPE_MAX)
10035 idr_remove(&pmu_idr, pmu->type);
10036 if (pmu_bus_running) {
10037 if (pmu->nr_addr_filters)
10038 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10039 device_del(pmu->dev);
10040 put_device(pmu->dev);
10042 free_pmu_context(pmu);
10043 mutex_unlock(&pmus_lock);
10045 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10047 static inline bool has_extended_regs(struct perf_event *event)
10049 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10050 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10053 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10055 struct perf_event_context *ctx = NULL;
10058 if (!try_module_get(pmu->module))
10062 * A number of pmu->event_init() methods iterate the sibling_list to,
10063 * for example, validate if the group fits on the PMU. Therefore,
10064 * if this is a sibling event, acquire the ctx->mutex to protect
10065 * the sibling_list.
10067 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10069 * This ctx->mutex can nest when we're called through
10070 * inheritance. See the perf_event_ctx_lock_nested() comment.
10072 ctx = perf_event_ctx_lock_nested(event->group_leader,
10073 SINGLE_DEPTH_NESTING);
10078 ret = pmu->event_init(event);
10081 perf_event_ctx_unlock(event->group_leader, ctx);
10084 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10085 has_extended_regs(event))
10088 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10089 event_has_any_exclude_flag(event))
10092 if (ret && event->destroy)
10093 event->destroy(event);
10097 module_put(pmu->module);
10102 static struct pmu *perf_init_event(struct perf_event *event)
10108 idx = srcu_read_lock(&pmus_srcu);
10110 /* Try parent's PMU first: */
10111 if (event->parent && event->parent->pmu) {
10112 pmu = event->parent->pmu;
10113 ret = perf_try_init_event(pmu, event);
10119 pmu = idr_find(&pmu_idr, event->attr.type);
10122 ret = perf_try_init_event(pmu, event);
10124 pmu = ERR_PTR(ret);
10128 list_for_each_entry_rcu(pmu, &pmus, entry) {
10129 ret = perf_try_init_event(pmu, event);
10133 if (ret != -ENOENT) {
10134 pmu = ERR_PTR(ret);
10138 pmu = ERR_PTR(-ENOENT);
10140 srcu_read_unlock(&pmus_srcu, idx);
10145 static void attach_sb_event(struct perf_event *event)
10147 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10149 raw_spin_lock(&pel->lock);
10150 list_add_rcu(&event->sb_list, &pel->list);
10151 raw_spin_unlock(&pel->lock);
10155 * We keep a list of all !task (and therefore per-cpu) events
10156 * that need to receive side-band records.
10158 * This avoids having to scan all the various PMU per-cpu contexts
10159 * looking for them.
10161 static void account_pmu_sb_event(struct perf_event *event)
10163 if (is_sb_event(event))
10164 attach_sb_event(event);
10167 static void account_event_cpu(struct perf_event *event, int cpu)
10172 if (is_cgroup_event(event))
10173 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10176 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10177 static void account_freq_event_nohz(void)
10179 #ifdef CONFIG_NO_HZ_FULL
10180 /* Lock so we don't race with concurrent unaccount */
10181 spin_lock(&nr_freq_lock);
10182 if (atomic_inc_return(&nr_freq_events) == 1)
10183 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10184 spin_unlock(&nr_freq_lock);
10188 static void account_freq_event(void)
10190 if (tick_nohz_full_enabled())
10191 account_freq_event_nohz();
10193 atomic_inc(&nr_freq_events);
10197 static void account_event(struct perf_event *event)
10204 if (event->attach_state & PERF_ATTACH_TASK)
10206 if (event->attr.mmap || event->attr.mmap_data)
10207 atomic_inc(&nr_mmap_events);
10208 if (event->attr.comm)
10209 atomic_inc(&nr_comm_events);
10210 if (event->attr.namespaces)
10211 atomic_inc(&nr_namespaces_events);
10212 if (event->attr.task)
10213 atomic_inc(&nr_task_events);
10214 if (event->attr.freq)
10215 account_freq_event();
10216 if (event->attr.context_switch) {
10217 atomic_inc(&nr_switch_events);
10220 if (has_branch_stack(event))
10222 if (is_cgroup_event(event))
10224 if (event->attr.ksymbol)
10225 atomic_inc(&nr_ksymbol_events);
10226 if (event->attr.bpf_event)
10227 atomic_inc(&nr_bpf_events);
10231 * We need the mutex here because static_branch_enable()
10232 * must complete *before* the perf_sched_count increment
10235 if (atomic_inc_not_zero(&perf_sched_count))
10238 mutex_lock(&perf_sched_mutex);
10239 if (!atomic_read(&perf_sched_count)) {
10240 static_branch_enable(&perf_sched_events);
10242 * Guarantee that all CPUs observe they key change and
10243 * call the perf scheduling hooks before proceeding to
10244 * install events that need them.
10249 * Now that we have waited for the sync_sched(), allow further
10250 * increments to by-pass the mutex.
10252 atomic_inc(&perf_sched_count);
10253 mutex_unlock(&perf_sched_mutex);
10257 account_event_cpu(event, event->cpu);
10259 account_pmu_sb_event(event);
10263 * Allocate and initialize an event structure
10265 static struct perf_event *
10266 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10267 struct task_struct *task,
10268 struct perf_event *group_leader,
10269 struct perf_event *parent_event,
10270 perf_overflow_handler_t overflow_handler,
10271 void *context, int cgroup_fd)
10274 struct perf_event *event;
10275 struct hw_perf_event *hwc;
10276 long err = -EINVAL;
10278 if ((unsigned)cpu >= nr_cpu_ids) {
10279 if (!task || cpu != -1)
10280 return ERR_PTR(-EINVAL);
10283 event = kzalloc(sizeof(*event), GFP_KERNEL);
10285 return ERR_PTR(-ENOMEM);
10288 * Single events are their own group leaders, with an
10289 * empty sibling list:
10292 group_leader = event;
10294 mutex_init(&event->child_mutex);
10295 INIT_LIST_HEAD(&event->child_list);
10297 INIT_LIST_HEAD(&event->event_entry);
10298 INIT_LIST_HEAD(&event->sibling_list);
10299 INIT_LIST_HEAD(&event->active_list);
10300 init_event_group(event);
10301 INIT_LIST_HEAD(&event->rb_entry);
10302 INIT_LIST_HEAD(&event->active_entry);
10303 INIT_LIST_HEAD(&event->addr_filters.list);
10304 INIT_HLIST_NODE(&event->hlist_entry);
10307 init_waitqueue_head(&event->waitq);
10308 event->pending_disable = -1;
10309 init_irq_work(&event->pending, perf_pending_event);
10311 mutex_init(&event->mmap_mutex);
10312 raw_spin_lock_init(&event->addr_filters.lock);
10314 atomic_long_set(&event->refcount, 1);
10316 event->attr = *attr;
10317 event->group_leader = group_leader;
10321 event->parent = parent_event;
10323 event->ns = get_pid_ns(task_active_pid_ns(current));
10324 event->id = atomic64_inc_return(&perf_event_id);
10326 event->state = PERF_EVENT_STATE_INACTIVE;
10329 event->attach_state = PERF_ATTACH_TASK;
10331 * XXX pmu::event_init needs to know what task to account to
10332 * and we cannot use the ctx information because we need the
10333 * pmu before we get a ctx.
10335 get_task_struct(task);
10336 event->hw.target = task;
10339 event->clock = &local_clock;
10341 event->clock = parent_event->clock;
10343 if (!overflow_handler && parent_event) {
10344 overflow_handler = parent_event->overflow_handler;
10345 context = parent_event->overflow_handler_context;
10346 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10347 if (overflow_handler == bpf_overflow_handler) {
10348 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10350 if (IS_ERR(prog)) {
10351 err = PTR_ERR(prog);
10354 event->prog = prog;
10355 event->orig_overflow_handler =
10356 parent_event->orig_overflow_handler;
10361 if (overflow_handler) {
10362 event->overflow_handler = overflow_handler;
10363 event->overflow_handler_context = context;
10364 } else if (is_write_backward(event)){
10365 event->overflow_handler = perf_event_output_backward;
10366 event->overflow_handler_context = NULL;
10368 event->overflow_handler = perf_event_output_forward;
10369 event->overflow_handler_context = NULL;
10372 perf_event__state_init(event);
10377 hwc->sample_period = attr->sample_period;
10378 if (attr->freq && attr->sample_freq)
10379 hwc->sample_period = 1;
10380 hwc->last_period = hwc->sample_period;
10382 local64_set(&hwc->period_left, hwc->sample_period);
10385 * We currently do not support PERF_SAMPLE_READ on inherited events.
10386 * See perf_output_read().
10388 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10391 if (!has_branch_stack(event))
10392 event->attr.branch_sample_type = 0;
10394 if (cgroup_fd != -1) {
10395 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10400 pmu = perf_init_event(event);
10402 err = PTR_ERR(pmu);
10406 err = exclusive_event_init(event);
10410 if (has_addr_filter(event)) {
10411 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10412 sizeof(struct perf_addr_filter_range),
10414 if (!event->addr_filter_ranges) {
10420 * Clone the parent's vma offsets: they are valid until exec()
10421 * even if the mm is not shared with the parent.
10423 if (event->parent) {
10424 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10426 raw_spin_lock_irq(&ifh->lock);
10427 memcpy(event->addr_filter_ranges,
10428 event->parent->addr_filter_ranges,
10429 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10430 raw_spin_unlock_irq(&ifh->lock);
10433 /* force hw sync on the address filters */
10434 event->addr_filters_gen = 1;
10437 if (!event->parent) {
10438 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10439 err = get_callchain_buffers(attr->sample_max_stack);
10441 goto err_addr_filters;
10445 /* symmetric to unaccount_event() in _free_event() */
10446 account_event(event);
10451 kfree(event->addr_filter_ranges);
10454 exclusive_event_destroy(event);
10457 if (event->destroy)
10458 event->destroy(event);
10459 module_put(pmu->module);
10461 if (is_cgroup_event(event))
10462 perf_detach_cgroup(event);
10464 put_pid_ns(event->ns);
10465 if (event->hw.target)
10466 put_task_struct(event->hw.target);
10469 return ERR_PTR(err);
10472 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10473 struct perf_event_attr *attr)
10478 if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
10482 * zero the full structure, so that a short copy will be nice.
10484 memset(attr, 0, sizeof(*attr));
10486 ret = get_user(size, &uattr->size);
10490 if (size > PAGE_SIZE) /* silly large */
10493 if (!size) /* abi compat */
10494 size = PERF_ATTR_SIZE_VER0;
10496 if (size < PERF_ATTR_SIZE_VER0)
10500 * If we're handed a bigger struct than we know of,
10501 * ensure all the unknown bits are 0 - i.e. new
10502 * user-space does not rely on any kernel feature
10503 * extensions we dont know about yet.
10505 if (size > sizeof(*attr)) {
10506 unsigned char __user *addr;
10507 unsigned char __user *end;
10510 addr = (void __user *)uattr + sizeof(*attr);
10511 end = (void __user *)uattr + size;
10513 for (; addr < end; addr++) {
10514 ret = get_user(val, addr);
10520 size = sizeof(*attr);
10523 ret = copy_from_user(attr, uattr, size);
10529 if (attr->__reserved_1)
10532 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10535 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10538 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10539 u64 mask = attr->branch_sample_type;
10541 /* only using defined bits */
10542 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10545 /* at least one branch bit must be set */
10546 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10549 /* propagate priv level, when not set for branch */
10550 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10552 /* exclude_kernel checked on syscall entry */
10553 if (!attr->exclude_kernel)
10554 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10556 if (!attr->exclude_user)
10557 mask |= PERF_SAMPLE_BRANCH_USER;
10559 if (!attr->exclude_hv)
10560 mask |= PERF_SAMPLE_BRANCH_HV;
10562 * adjust user setting (for HW filter setup)
10564 attr->branch_sample_type = mask;
10566 /* privileged levels capture (kernel, hv): check permissions */
10567 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10568 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10572 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10573 ret = perf_reg_validate(attr->sample_regs_user);
10578 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10579 if (!arch_perf_have_user_stack_dump())
10583 * We have __u32 type for the size, but so far
10584 * we can only use __u16 as maximum due to the
10585 * __u16 sample size limit.
10587 if (attr->sample_stack_user >= USHRT_MAX)
10589 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10593 if (!attr->sample_max_stack)
10594 attr->sample_max_stack = sysctl_perf_event_max_stack;
10596 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10597 ret = perf_reg_validate(attr->sample_regs_intr);
10602 put_user(sizeof(*attr), &uattr->size);
10608 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10610 struct ring_buffer *rb = NULL;
10616 /* don't allow circular references */
10617 if (event == output_event)
10621 * Don't allow cross-cpu buffers
10623 if (output_event->cpu != event->cpu)
10627 * If its not a per-cpu rb, it must be the same task.
10629 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10633 * Mixing clocks in the same buffer is trouble you don't need.
10635 if (output_event->clock != event->clock)
10639 * Either writing ring buffer from beginning or from end.
10640 * Mixing is not allowed.
10642 if (is_write_backward(output_event) != is_write_backward(event))
10646 * If both events generate aux data, they must be on the same PMU
10648 if (has_aux(event) && has_aux(output_event) &&
10649 event->pmu != output_event->pmu)
10653 mutex_lock(&event->mmap_mutex);
10654 /* Can't redirect output if we've got an active mmap() */
10655 if (atomic_read(&event->mmap_count))
10658 if (output_event) {
10659 /* get the rb we want to redirect to */
10660 rb = ring_buffer_get(output_event);
10665 ring_buffer_attach(event, rb);
10669 mutex_unlock(&event->mmap_mutex);
10675 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10681 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10684 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10686 bool nmi_safe = false;
10689 case CLOCK_MONOTONIC:
10690 event->clock = &ktime_get_mono_fast_ns;
10694 case CLOCK_MONOTONIC_RAW:
10695 event->clock = &ktime_get_raw_fast_ns;
10699 case CLOCK_REALTIME:
10700 event->clock = &ktime_get_real_ns;
10703 case CLOCK_BOOTTIME:
10704 event->clock = &ktime_get_boottime_ns;
10708 event->clock = &ktime_get_clocktai_ns;
10715 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10722 * Variation on perf_event_ctx_lock_nested(), except we take two context
10725 static struct perf_event_context *
10726 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10727 struct perf_event_context *ctx)
10729 struct perf_event_context *gctx;
10733 gctx = READ_ONCE(group_leader->ctx);
10734 if (!refcount_inc_not_zero(&gctx->refcount)) {
10740 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10742 if (group_leader->ctx != gctx) {
10743 mutex_unlock(&ctx->mutex);
10744 mutex_unlock(&gctx->mutex);
10753 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10755 * @attr_uptr: event_id type attributes for monitoring/sampling
10758 * @group_fd: group leader event fd
10760 SYSCALL_DEFINE5(perf_event_open,
10761 struct perf_event_attr __user *, attr_uptr,
10762 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10764 struct perf_event *group_leader = NULL, *output_event = NULL;
10765 struct perf_event *event, *sibling;
10766 struct perf_event_attr attr;
10767 struct perf_event_context *ctx, *uninitialized_var(gctx);
10768 struct file *event_file = NULL;
10769 struct fd group = {NULL, 0};
10770 struct task_struct *task = NULL;
10773 int move_group = 0;
10775 int f_flags = O_RDWR;
10776 int cgroup_fd = -1;
10778 /* for future expandability... */
10779 if (flags & ~PERF_FLAG_ALL)
10782 err = perf_copy_attr(attr_uptr, &attr);
10786 if (!attr.exclude_kernel) {
10787 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10791 if (attr.namespaces) {
10792 if (!capable(CAP_SYS_ADMIN))
10797 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10800 if (attr.sample_period & (1ULL << 63))
10804 /* Only privileged users can get physical addresses */
10805 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10806 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10810 * In cgroup mode, the pid argument is used to pass the fd
10811 * opened to the cgroup directory in cgroupfs. The cpu argument
10812 * designates the cpu on which to monitor threads from that
10815 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10818 if (flags & PERF_FLAG_FD_CLOEXEC)
10819 f_flags |= O_CLOEXEC;
10821 event_fd = get_unused_fd_flags(f_flags);
10825 if (group_fd != -1) {
10826 err = perf_fget_light(group_fd, &group);
10829 group_leader = group.file->private_data;
10830 if (flags & PERF_FLAG_FD_OUTPUT)
10831 output_event = group_leader;
10832 if (flags & PERF_FLAG_FD_NO_GROUP)
10833 group_leader = NULL;
10836 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10837 task = find_lively_task_by_vpid(pid);
10838 if (IS_ERR(task)) {
10839 err = PTR_ERR(task);
10844 if (task && group_leader &&
10845 group_leader->attr.inherit != attr.inherit) {
10851 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10856 * Reuse ptrace permission checks for now.
10858 * We must hold cred_guard_mutex across this and any potential
10859 * perf_install_in_context() call for this new event to
10860 * serialize against exec() altering our credentials (and the
10861 * perf_event_exit_task() that could imply).
10864 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10868 if (flags & PERF_FLAG_PID_CGROUP)
10871 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10872 NULL, NULL, cgroup_fd);
10873 if (IS_ERR(event)) {
10874 err = PTR_ERR(event);
10878 if (is_sampling_event(event)) {
10879 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10886 * Special case software events and allow them to be part of
10887 * any hardware group.
10891 if (attr.use_clockid) {
10892 err = perf_event_set_clock(event, attr.clockid);
10897 if (pmu->task_ctx_nr == perf_sw_context)
10898 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10900 if (group_leader) {
10901 if (is_software_event(event) &&
10902 !in_software_context(group_leader)) {
10904 * If the event is a sw event, but the group_leader
10905 * is on hw context.
10907 * Allow the addition of software events to hw
10908 * groups, this is safe because software events
10909 * never fail to schedule.
10911 pmu = group_leader->ctx->pmu;
10912 } else if (!is_software_event(event) &&
10913 is_software_event(group_leader) &&
10914 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10916 * In case the group is a pure software group, and we
10917 * try to add a hardware event, move the whole group to
10918 * the hardware context.
10925 * Get the target context (task or percpu):
10927 ctx = find_get_context(pmu, task, event);
10929 err = PTR_ERR(ctx);
10933 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10939 * Look up the group leader (we will attach this event to it):
10941 if (group_leader) {
10945 * Do not allow a recursive hierarchy (this new sibling
10946 * becoming part of another group-sibling):
10948 if (group_leader->group_leader != group_leader)
10951 /* All events in a group should have the same clock */
10952 if (group_leader->clock != event->clock)
10956 * Make sure we're both events for the same CPU;
10957 * grouping events for different CPUs is broken; since
10958 * you can never concurrently schedule them anyhow.
10960 if (group_leader->cpu != event->cpu)
10964 * Make sure we're both on the same task, or both
10967 if (group_leader->ctx->task != ctx->task)
10971 * Do not allow to attach to a group in a different task
10972 * or CPU context. If we're moving SW events, we'll fix
10973 * this up later, so allow that.
10975 if (!move_group && group_leader->ctx != ctx)
10979 * Only a group leader can be exclusive or pinned
10981 if (attr.exclusive || attr.pinned)
10985 if (output_event) {
10986 err = perf_event_set_output(event, output_event);
10991 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10993 if (IS_ERR(event_file)) {
10994 err = PTR_ERR(event_file);
11000 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11002 if (gctx->task == TASK_TOMBSTONE) {
11008 * Check if we raced against another sys_perf_event_open() call
11009 * moving the software group underneath us.
11011 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11013 * If someone moved the group out from under us, check
11014 * if this new event wound up on the same ctx, if so
11015 * its the regular !move_group case, otherwise fail.
11021 perf_event_ctx_unlock(group_leader, gctx);
11026 mutex_lock(&ctx->mutex);
11029 if (ctx->task == TASK_TOMBSTONE) {
11034 if (!perf_event_validate_size(event)) {
11041 * Check if the @cpu we're creating an event for is online.
11043 * We use the perf_cpu_context::ctx::mutex to serialize against
11044 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11046 struct perf_cpu_context *cpuctx =
11047 container_of(ctx, struct perf_cpu_context, ctx);
11049 if (!cpuctx->online) {
11057 * Must be under the same ctx::mutex as perf_install_in_context(),
11058 * because we need to serialize with concurrent event creation.
11060 if (!exclusive_event_installable(event, ctx)) {
11061 /* exclusive and group stuff are assumed mutually exclusive */
11062 WARN_ON_ONCE(move_group);
11068 WARN_ON_ONCE(ctx->parent_ctx);
11071 * This is the point on no return; we cannot fail hereafter. This is
11072 * where we start modifying current state.
11077 * See perf_event_ctx_lock() for comments on the details
11078 * of swizzling perf_event::ctx.
11080 perf_remove_from_context(group_leader, 0);
11083 for_each_sibling_event(sibling, group_leader) {
11084 perf_remove_from_context(sibling, 0);
11089 * Wait for everybody to stop referencing the events through
11090 * the old lists, before installing it on new lists.
11095 * Install the group siblings before the group leader.
11097 * Because a group leader will try and install the entire group
11098 * (through the sibling list, which is still in-tact), we can
11099 * end up with siblings installed in the wrong context.
11101 * By installing siblings first we NO-OP because they're not
11102 * reachable through the group lists.
11104 for_each_sibling_event(sibling, group_leader) {
11105 perf_event__state_init(sibling);
11106 perf_install_in_context(ctx, sibling, sibling->cpu);
11111 * Removing from the context ends up with disabled
11112 * event. What we want here is event in the initial
11113 * startup state, ready to be add into new context.
11115 perf_event__state_init(group_leader);
11116 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11121 * Precalculate sample_data sizes; do while holding ctx::mutex such
11122 * that we're serialized against further additions and before
11123 * perf_install_in_context() which is the point the event is active and
11124 * can use these values.
11126 perf_event__header_size(event);
11127 perf_event__id_header_size(event);
11129 event->owner = current;
11131 perf_install_in_context(ctx, event, event->cpu);
11132 perf_unpin_context(ctx);
11135 perf_event_ctx_unlock(group_leader, gctx);
11136 mutex_unlock(&ctx->mutex);
11139 mutex_unlock(&task->signal->cred_guard_mutex);
11140 put_task_struct(task);
11143 mutex_lock(¤t->perf_event_mutex);
11144 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11145 mutex_unlock(¤t->perf_event_mutex);
11148 * Drop the reference on the group_event after placing the
11149 * new event on the sibling_list. This ensures destruction
11150 * of the group leader will find the pointer to itself in
11151 * perf_group_detach().
11154 fd_install(event_fd, event_file);
11159 perf_event_ctx_unlock(group_leader, gctx);
11160 mutex_unlock(&ctx->mutex);
11164 perf_unpin_context(ctx);
11168 * If event_file is set, the fput() above will have called ->release()
11169 * and that will take care of freeing the event.
11175 mutex_unlock(&task->signal->cred_guard_mutex);
11178 put_task_struct(task);
11182 put_unused_fd(event_fd);
11187 * perf_event_create_kernel_counter
11189 * @attr: attributes of the counter to create
11190 * @cpu: cpu in which the counter is bound
11191 * @task: task to profile (NULL for percpu)
11193 struct perf_event *
11194 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11195 struct task_struct *task,
11196 perf_overflow_handler_t overflow_handler,
11199 struct perf_event_context *ctx;
11200 struct perf_event *event;
11204 * Get the target context (task or percpu):
11207 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11208 overflow_handler, context, -1);
11209 if (IS_ERR(event)) {
11210 err = PTR_ERR(event);
11214 /* Mark owner so we could distinguish it from user events. */
11215 event->owner = TASK_TOMBSTONE;
11217 ctx = find_get_context(event->pmu, task, event);
11219 err = PTR_ERR(ctx);
11223 WARN_ON_ONCE(ctx->parent_ctx);
11224 mutex_lock(&ctx->mutex);
11225 if (ctx->task == TASK_TOMBSTONE) {
11232 * Check if the @cpu we're creating an event for is online.
11234 * We use the perf_cpu_context::ctx::mutex to serialize against
11235 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11237 struct perf_cpu_context *cpuctx =
11238 container_of(ctx, struct perf_cpu_context, ctx);
11239 if (!cpuctx->online) {
11245 if (!exclusive_event_installable(event, ctx)) {
11250 perf_install_in_context(ctx, event, cpu);
11251 perf_unpin_context(ctx);
11252 mutex_unlock(&ctx->mutex);
11257 mutex_unlock(&ctx->mutex);
11258 perf_unpin_context(ctx);
11263 return ERR_PTR(err);
11265 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11267 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11269 struct perf_event_context *src_ctx;
11270 struct perf_event_context *dst_ctx;
11271 struct perf_event *event, *tmp;
11274 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11275 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11278 * See perf_event_ctx_lock() for comments on the details
11279 * of swizzling perf_event::ctx.
11281 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11282 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11284 perf_remove_from_context(event, 0);
11285 unaccount_event_cpu(event, src_cpu);
11287 list_add(&event->migrate_entry, &events);
11291 * Wait for the events to quiesce before re-instating them.
11296 * Re-instate events in 2 passes.
11298 * Skip over group leaders and only install siblings on this first
11299 * pass, siblings will not get enabled without a leader, however a
11300 * leader will enable its siblings, even if those are still on the old
11303 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11304 if (event->group_leader == event)
11307 list_del(&event->migrate_entry);
11308 if (event->state >= PERF_EVENT_STATE_OFF)
11309 event->state = PERF_EVENT_STATE_INACTIVE;
11310 account_event_cpu(event, dst_cpu);
11311 perf_install_in_context(dst_ctx, event, dst_cpu);
11316 * Once all the siblings are setup properly, install the group leaders
11319 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11320 list_del(&event->migrate_entry);
11321 if (event->state >= PERF_EVENT_STATE_OFF)
11322 event->state = PERF_EVENT_STATE_INACTIVE;
11323 account_event_cpu(event, dst_cpu);
11324 perf_install_in_context(dst_ctx, event, dst_cpu);
11327 mutex_unlock(&dst_ctx->mutex);
11328 mutex_unlock(&src_ctx->mutex);
11330 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11332 static void sync_child_event(struct perf_event *child_event,
11333 struct task_struct *child)
11335 struct perf_event *parent_event = child_event->parent;
11338 if (child_event->attr.inherit_stat)
11339 perf_event_read_event(child_event, child);
11341 child_val = perf_event_count(child_event);
11344 * Add back the child's count to the parent's count:
11346 atomic64_add(child_val, &parent_event->child_count);
11347 atomic64_add(child_event->total_time_enabled,
11348 &parent_event->child_total_time_enabled);
11349 atomic64_add(child_event->total_time_running,
11350 &parent_event->child_total_time_running);
11354 perf_event_exit_event(struct perf_event *child_event,
11355 struct perf_event_context *child_ctx,
11356 struct task_struct *child)
11358 struct perf_event *parent_event = child_event->parent;
11361 * Do not destroy the 'original' grouping; because of the context
11362 * switch optimization the original events could've ended up in a
11363 * random child task.
11365 * If we were to destroy the original group, all group related
11366 * operations would cease to function properly after this random
11369 * Do destroy all inherited groups, we don't care about those
11370 * and being thorough is better.
11372 raw_spin_lock_irq(&child_ctx->lock);
11373 WARN_ON_ONCE(child_ctx->is_active);
11376 perf_group_detach(child_event);
11377 list_del_event(child_event, child_ctx);
11378 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11379 raw_spin_unlock_irq(&child_ctx->lock);
11382 * Parent events are governed by their filedesc, retain them.
11384 if (!parent_event) {
11385 perf_event_wakeup(child_event);
11389 * Child events can be cleaned up.
11392 sync_child_event(child_event, child);
11395 * Remove this event from the parent's list
11397 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11398 mutex_lock(&parent_event->child_mutex);
11399 list_del_init(&child_event->child_list);
11400 mutex_unlock(&parent_event->child_mutex);
11403 * Kick perf_poll() for is_event_hup().
11405 perf_event_wakeup(parent_event);
11406 free_event(child_event);
11407 put_event(parent_event);
11410 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11412 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11413 struct perf_event *child_event, *next;
11415 WARN_ON_ONCE(child != current);
11417 child_ctx = perf_pin_task_context(child, ctxn);
11422 * In order to reduce the amount of tricky in ctx tear-down, we hold
11423 * ctx::mutex over the entire thing. This serializes against almost
11424 * everything that wants to access the ctx.
11426 * The exception is sys_perf_event_open() /
11427 * perf_event_create_kernel_count() which does find_get_context()
11428 * without ctx::mutex (it cannot because of the move_group double mutex
11429 * lock thing). See the comments in perf_install_in_context().
11431 mutex_lock(&child_ctx->mutex);
11434 * In a single ctx::lock section, de-schedule the events and detach the
11435 * context from the task such that we cannot ever get it scheduled back
11438 raw_spin_lock_irq(&child_ctx->lock);
11439 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11442 * Now that the context is inactive, destroy the task <-> ctx relation
11443 * and mark the context dead.
11445 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11446 put_ctx(child_ctx); /* cannot be last */
11447 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11448 put_task_struct(current); /* cannot be last */
11450 clone_ctx = unclone_ctx(child_ctx);
11451 raw_spin_unlock_irq(&child_ctx->lock);
11454 put_ctx(clone_ctx);
11457 * Report the task dead after unscheduling the events so that we
11458 * won't get any samples after PERF_RECORD_EXIT. We can however still
11459 * get a few PERF_RECORD_READ events.
11461 perf_event_task(child, child_ctx, 0);
11463 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11464 perf_event_exit_event(child_event, child_ctx, child);
11466 mutex_unlock(&child_ctx->mutex);
11468 put_ctx(child_ctx);
11472 * When a child task exits, feed back event values to parent events.
11474 * Can be called with cred_guard_mutex held when called from
11475 * install_exec_creds().
11477 void perf_event_exit_task(struct task_struct *child)
11479 struct perf_event *event, *tmp;
11482 mutex_lock(&child->perf_event_mutex);
11483 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11485 list_del_init(&event->owner_entry);
11488 * Ensure the list deletion is visible before we clear
11489 * the owner, closes a race against perf_release() where
11490 * we need to serialize on the owner->perf_event_mutex.
11492 smp_store_release(&event->owner, NULL);
11494 mutex_unlock(&child->perf_event_mutex);
11496 for_each_task_context_nr(ctxn)
11497 perf_event_exit_task_context(child, ctxn);
11500 * The perf_event_exit_task_context calls perf_event_task
11501 * with child's task_ctx, which generates EXIT events for
11502 * child contexts and sets child->perf_event_ctxp[] to NULL.
11503 * At this point we need to send EXIT events to cpu contexts.
11505 perf_event_task(child, NULL, 0);
11508 static void perf_free_event(struct perf_event *event,
11509 struct perf_event_context *ctx)
11511 struct perf_event *parent = event->parent;
11513 if (WARN_ON_ONCE(!parent))
11516 mutex_lock(&parent->child_mutex);
11517 list_del_init(&event->child_list);
11518 mutex_unlock(&parent->child_mutex);
11522 raw_spin_lock_irq(&ctx->lock);
11523 perf_group_detach(event);
11524 list_del_event(event, ctx);
11525 raw_spin_unlock_irq(&ctx->lock);
11530 * Free an unexposed, unused context as created by inheritance by
11531 * perf_event_init_task below, used by fork() in case of fail.
11533 * Not all locks are strictly required, but take them anyway to be nice and
11534 * help out with the lockdep assertions.
11536 void perf_event_free_task(struct task_struct *task)
11538 struct perf_event_context *ctx;
11539 struct perf_event *event, *tmp;
11542 for_each_task_context_nr(ctxn) {
11543 ctx = task->perf_event_ctxp[ctxn];
11547 mutex_lock(&ctx->mutex);
11548 raw_spin_lock_irq(&ctx->lock);
11550 * Destroy the task <-> ctx relation and mark the context dead.
11552 * This is important because even though the task hasn't been
11553 * exposed yet the context has been (through child_list).
11555 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11556 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11557 put_task_struct(task); /* cannot be last */
11558 raw_spin_unlock_irq(&ctx->lock);
11560 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11561 perf_free_event(event, ctx);
11563 mutex_unlock(&ctx->mutex);
11568 void perf_event_delayed_put(struct task_struct *task)
11572 for_each_task_context_nr(ctxn)
11573 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11576 struct file *perf_event_get(unsigned int fd)
11580 file = fget_raw(fd);
11582 return ERR_PTR(-EBADF);
11584 if (file->f_op != &perf_fops) {
11586 return ERR_PTR(-EBADF);
11592 const struct perf_event *perf_get_event(struct file *file)
11594 if (file->f_op != &perf_fops)
11595 return ERR_PTR(-EINVAL);
11597 return file->private_data;
11600 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11603 return ERR_PTR(-EINVAL);
11605 return &event->attr;
11609 * Inherit an event from parent task to child task.
11612 * - valid pointer on success
11613 * - NULL for orphaned events
11614 * - IS_ERR() on error
11616 static struct perf_event *
11617 inherit_event(struct perf_event *parent_event,
11618 struct task_struct *parent,
11619 struct perf_event_context *parent_ctx,
11620 struct task_struct *child,
11621 struct perf_event *group_leader,
11622 struct perf_event_context *child_ctx)
11624 enum perf_event_state parent_state = parent_event->state;
11625 struct perf_event *child_event;
11626 unsigned long flags;
11629 * Instead of creating recursive hierarchies of events,
11630 * we link inherited events back to the original parent,
11631 * which has a filp for sure, which we use as the reference
11634 if (parent_event->parent)
11635 parent_event = parent_event->parent;
11637 child_event = perf_event_alloc(&parent_event->attr,
11640 group_leader, parent_event,
11642 if (IS_ERR(child_event))
11643 return child_event;
11646 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11647 !child_ctx->task_ctx_data) {
11648 struct pmu *pmu = child_event->pmu;
11650 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11652 if (!child_ctx->task_ctx_data) {
11653 free_event(child_event);
11659 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11660 * must be under the same lock in order to serialize against
11661 * perf_event_release_kernel(), such that either we must observe
11662 * is_orphaned_event() or they will observe us on the child_list.
11664 mutex_lock(&parent_event->child_mutex);
11665 if (is_orphaned_event(parent_event) ||
11666 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11667 mutex_unlock(&parent_event->child_mutex);
11668 /* task_ctx_data is freed with child_ctx */
11669 free_event(child_event);
11673 get_ctx(child_ctx);
11676 * Make the child state follow the state of the parent event,
11677 * not its attr.disabled bit. We hold the parent's mutex,
11678 * so we won't race with perf_event_{en, dis}able_family.
11680 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11681 child_event->state = PERF_EVENT_STATE_INACTIVE;
11683 child_event->state = PERF_EVENT_STATE_OFF;
11685 if (parent_event->attr.freq) {
11686 u64 sample_period = parent_event->hw.sample_period;
11687 struct hw_perf_event *hwc = &child_event->hw;
11689 hwc->sample_period = sample_period;
11690 hwc->last_period = sample_period;
11692 local64_set(&hwc->period_left, sample_period);
11695 child_event->ctx = child_ctx;
11696 child_event->overflow_handler = parent_event->overflow_handler;
11697 child_event->overflow_handler_context
11698 = parent_event->overflow_handler_context;
11701 * Precalculate sample_data sizes
11703 perf_event__header_size(child_event);
11704 perf_event__id_header_size(child_event);
11707 * Link it up in the child's context:
11709 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11710 add_event_to_ctx(child_event, child_ctx);
11711 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11714 * Link this into the parent event's child list
11716 list_add_tail(&child_event->child_list, &parent_event->child_list);
11717 mutex_unlock(&parent_event->child_mutex);
11719 return child_event;
11723 * Inherits an event group.
11725 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11726 * This matches with perf_event_release_kernel() removing all child events.
11732 static int inherit_group(struct perf_event *parent_event,
11733 struct task_struct *parent,
11734 struct perf_event_context *parent_ctx,
11735 struct task_struct *child,
11736 struct perf_event_context *child_ctx)
11738 struct perf_event *leader;
11739 struct perf_event *sub;
11740 struct perf_event *child_ctr;
11742 leader = inherit_event(parent_event, parent, parent_ctx,
11743 child, NULL, child_ctx);
11744 if (IS_ERR(leader))
11745 return PTR_ERR(leader);
11747 * @leader can be NULL here because of is_orphaned_event(). In this
11748 * case inherit_event() will create individual events, similar to what
11749 * perf_group_detach() would do anyway.
11751 for_each_sibling_event(sub, parent_event) {
11752 child_ctr = inherit_event(sub, parent, parent_ctx,
11753 child, leader, child_ctx);
11754 if (IS_ERR(child_ctr))
11755 return PTR_ERR(child_ctr);
11761 * Creates the child task context and tries to inherit the event-group.
11763 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11764 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11765 * consistent with perf_event_release_kernel() removing all child events.
11772 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11773 struct perf_event_context *parent_ctx,
11774 struct task_struct *child, int ctxn,
11775 int *inherited_all)
11778 struct perf_event_context *child_ctx;
11780 if (!event->attr.inherit) {
11781 *inherited_all = 0;
11785 child_ctx = child->perf_event_ctxp[ctxn];
11788 * This is executed from the parent task context, so
11789 * inherit events that have been marked for cloning.
11790 * First allocate and initialize a context for the
11793 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11797 child->perf_event_ctxp[ctxn] = child_ctx;
11800 ret = inherit_group(event, parent, parent_ctx,
11804 *inherited_all = 0;
11810 * Initialize the perf_event context in task_struct
11812 static int perf_event_init_context(struct task_struct *child, int ctxn)
11814 struct perf_event_context *child_ctx, *parent_ctx;
11815 struct perf_event_context *cloned_ctx;
11816 struct perf_event *event;
11817 struct task_struct *parent = current;
11818 int inherited_all = 1;
11819 unsigned long flags;
11822 if (likely(!parent->perf_event_ctxp[ctxn]))
11826 * If the parent's context is a clone, pin it so it won't get
11827 * swapped under us.
11829 parent_ctx = perf_pin_task_context(parent, ctxn);
11834 * No need to check if parent_ctx != NULL here; since we saw
11835 * it non-NULL earlier, the only reason for it to become NULL
11836 * is if we exit, and since we're currently in the middle of
11837 * a fork we can't be exiting at the same time.
11841 * Lock the parent list. No need to lock the child - not PID
11842 * hashed yet and not running, so nobody can access it.
11844 mutex_lock(&parent_ctx->mutex);
11847 * We dont have to disable NMIs - we are only looking at
11848 * the list, not manipulating it:
11850 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11851 ret = inherit_task_group(event, parent, parent_ctx,
11852 child, ctxn, &inherited_all);
11858 * We can't hold ctx->lock when iterating the ->flexible_group list due
11859 * to allocations, but we need to prevent rotation because
11860 * rotate_ctx() will change the list from interrupt context.
11862 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11863 parent_ctx->rotate_disable = 1;
11864 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11866 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11867 ret = inherit_task_group(event, parent, parent_ctx,
11868 child, ctxn, &inherited_all);
11873 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11874 parent_ctx->rotate_disable = 0;
11876 child_ctx = child->perf_event_ctxp[ctxn];
11878 if (child_ctx && inherited_all) {
11880 * Mark the child context as a clone of the parent
11881 * context, or of whatever the parent is a clone of.
11883 * Note that if the parent is a clone, the holding of
11884 * parent_ctx->lock avoids it from being uncloned.
11886 cloned_ctx = parent_ctx->parent_ctx;
11888 child_ctx->parent_ctx = cloned_ctx;
11889 child_ctx->parent_gen = parent_ctx->parent_gen;
11891 child_ctx->parent_ctx = parent_ctx;
11892 child_ctx->parent_gen = parent_ctx->generation;
11894 get_ctx(child_ctx->parent_ctx);
11897 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11899 mutex_unlock(&parent_ctx->mutex);
11901 perf_unpin_context(parent_ctx);
11902 put_ctx(parent_ctx);
11908 * Initialize the perf_event context in task_struct
11910 int perf_event_init_task(struct task_struct *child)
11914 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11915 mutex_init(&child->perf_event_mutex);
11916 INIT_LIST_HEAD(&child->perf_event_list);
11918 for_each_task_context_nr(ctxn) {
11919 ret = perf_event_init_context(child, ctxn);
11921 perf_event_free_task(child);
11929 static void __init perf_event_init_all_cpus(void)
11931 struct swevent_htable *swhash;
11934 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11936 for_each_possible_cpu(cpu) {
11937 swhash = &per_cpu(swevent_htable, cpu);
11938 mutex_init(&swhash->hlist_mutex);
11939 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11941 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11942 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11944 #ifdef CONFIG_CGROUP_PERF
11945 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11947 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11951 static void perf_swevent_init_cpu(unsigned int cpu)
11953 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11955 mutex_lock(&swhash->hlist_mutex);
11956 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11957 struct swevent_hlist *hlist;
11959 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11961 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11963 mutex_unlock(&swhash->hlist_mutex);
11966 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11967 static void __perf_event_exit_context(void *__info)
11969 struct perf_event_context *ctx = __info;
11970 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11971 struct perf_event *event;
11973 raw_spin_lock(&ctx->lock);
11974 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11975 list_for_each_entry(event, &ctx->event_list, event_entry)
11976 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11977 raw_spin_unlock(&ctx->lock);
11980 static void perf_event_exit_cpu_context(int cpu)
11982 struct perf_cpu_context *cpuctx;
11983 struct perf_event_context *ctx;
11986 mutex_lock(&pmus_lock);
11987 list_for_each_entry(pmu, &pmus, entry) {
11988 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11989 ctx = &cpuctx->ctx;
11991 mutex_lock(&ctx->mutex);
11992 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11993 cpuctx->online = 0;
11994 mutex_unlock(&ctx->mutex);
11996 cpumask_clear_cpu(cpu, perf_online_mask);
11997 mutex_unlock(&pmus_lock);
12001 static void perf_event_exit_cpu_context(int cpu) { }
12005 int perf_event_init_cpu(unsigned int cpu)
12007 struct perf_cpu_context *cpuctx;
12008 struct perf_event_context *ctx;
12011 perf_swevent_init_cpu(cpu);
12013 mutex_lock(&pmus_lock);
12014 cpumask_set_cpu(cpu, perf_online_mask);
12015 list_for_each_entry(pmu, &pmus, entry) {
12016 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12017 ctx = &cpuctx->ctx;
12019 mutex_lock(&ctx->mutex);
12020 cpuctx->online = 1;
12021 mutex_unlock(&ctx->mutex);
12023 mutex_unlock(&pmus_lock);
12028 int perf_event_exit_cpu(unsigned int cpu)
12030 perf_event_exit_cpu_context(cpu);
12035 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12039 for_each_online_cpu(cpu)
12040 perf_event_exit_cpu(cpu);
12046 * Run the perf reboot notifier at the very last possible moment so that
12047 * the generic watchdog code runs as long as possible.
12049 static struct notifier_block perf_reboot_notifier = {
12050 .notifier_call = perf_reboot,
12051 .priority = INT_MIN,
12054 void __init perf_event_init(void)
12058 idr_init(&pmu_idr);
12060 perf_event_init_all_cpus();
12061 init_srcu_struct(&pmus_srcu);
12062 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12063 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12064 perf_pmu_register(&perf_task_clock, NULL, -1);
12065 perf_tp_register();
12066 perf_event_init_cpu(smp_processor_id());
12067 register_reboot_notifier(&perf_reboot_notifier);
12069 ret = init_hw_breakpoint();
12070 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12073 * Build time assertion that we keep the data_head at the intended
12074 * location. IOW, validation we got the __reserved[] size right.
12076 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12080 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12083 struct perf_pmu_events_attr *pmu_attr =
12084 container_of(attr, struct perf_pmu_events_attr, attr);
12086 if (pmu_attr->event_str)
12087 return sprintf(page, "%s\n", pmu_attr->event_str);
12091 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12093 static int __init perf_event_sysfs_init(void)
12098 mutex_lock(&pmus_lock);
12100 ret = bus_register(&pmu_bus);
12104 list_for_each_entry(pmu, &pmus, entry) {
12105 if (!pmu->name || pmu->type < 0)
12108 ret = pmu_dev_alloc(pmu);
12109 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12111 pmu_bus_running = 1;
12115 mutex_unlock(&pmus_lock);
12119 device_initcall(perf_event_sysfs_init);
12121 #ifdef CONFIG_CGROUP_PERF
12122 static struct cgroup_subsys_state *
12123 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12125 struct perf_cgroup *jc;
12127 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12129 return ERR_PTR(-ENOMEM);
12131 jc->info = alloc_percpu(struct perf_cgroup_info);
12134 return ERR_PTR(-ENOMEM);
12140 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12142 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12144 free_percpu(jc->info);
12148 static int __perf_cgroup_move(void *info)
12150 struct task_struct *task = info;
12152 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12157 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12159 struct task_struct *task;
12160 struct cgroup_subsys_state *css;
12162 cgroup_taskset_for_each(task, css, tset)
12163 task_function_call(task, __perf_cgroup_move, task);
12166 struct cgroup_subsys perf_event_cgrp_subsys = {
12167 .css_alloc = perf_cgroup_css_alloc,
12168 .css_free = perf_cgroup_css_free,
12169 .attach = perf_cgroup_attach,
12171 * Implicitly enable on dfl hierarchy so that perf events can
12172 * always be filtered by cgroup2 path as long as perf_event
12173 * controller is not mounted on a legacy hierarchy.
12175 .implicit_on_dfl = true,
12178 #endif /* CONFIG_CGROUP_PERF */