1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/cgroup.h>
37 #include <linux/perf_event.h>
38 #include <linux/trace_events.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/module.h>
42 #include <linux/mman.h>
43 #include <linux/compat.h>
44 #include <linux/bpf.h>
45 #include <linux/filter.h>
46 #include <linux/namei.h>
47 #include <linux/parser.h>
48 #include <linux/sched/clock.h>
49 #include <linux/sched/mm.h>
50 #include <linux/proc_ns.h>
51 #include <linux/mount.h>
55 #include <asm/irq_regs.h>
57 typedef int (*remote_function_f)(void *);
59 struct remote_function_call {
60 struct task_struct *p;
61 remote_function_f func;
66 static void remote_function(void *data)
68 struct remote_function_call *tfc = data;
69 struct task_struct *p = tfc->p;
73 if (task_cpu(p) != smp_processor_id())
77 * Now that we're on right CPU with IRQs disabled, we can test
78 * if we hit the right task without races.
81 tfc->ret = -ESRCH; /* No such (running) process */
86 tfc->ret = tfc->func(tfc->info);
90 * task_function_call - call a function on the cpu on which a task runs
91 * @p: the task to evaluate
92 * @func: the function to be called
93 * @info: the function call argument
95 * Calls the function @func when the task is currently running. This might
96 * be on the current CPU, which just calls the function directly
98 * returns: @func return value, or
99 * -ESRCH - when the process isn't running
100 * -EAGAIN - when the process moved away
103 task_function_call(struct task_struct *p, remote_function_f func, void *info)
105 struct remote_function_call data = {
114 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
117 } while (ret == -EAGAIN);
123 * cpu_function_call - call a function on the cpu
124 * @func: the function to be called
125 * @info: the function call argument
127 * Calls the function @func on the remote cpu.
129 * returns: @func return value or -ENXIO when the cpu is offline
131 static int cpu_function_call(int cpu, remote_function_f func, void *info)
133 struct remote_function_call data = {
137 .ret = -ENXIO, /* No such CPU */
140 smp_call_function_single(cpu, remote_function, &data, 1);
145 static inline struct perf_cpu_context *
146 __get_cpu_context(struct perf_event_context *ctx)
148 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
151 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
152 struct perf_event_context *ctx)
154 raw_spin_lock(&cpuctx->ctx.lock);
156 raw_spin_lock(&ctx->lock);
159 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
160 struct perf_event_context *ctx)
163 raw_spin_unlock(&ctx->lock);
164 raw_spin_unlock(&cpuctx->ctx.lock);
167 #define TASK_TOMBSTONE ((void *)-1L)
169 static bool is_kernel_event(struct perf_event *event)
171 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
175 * On task ctx scheduling...
177 * When !ctx->nr_events a task context will not be scheduled. This means
178 * we can disable the scheduler hooks (for performance) without leaving
179 * pending task ctx state.
181 * This however results in two special cases:
183 * - removing the last event from a task ctx; this is relatively straight
184 * forward and is done in __perf_remove_from_context.
186 * - adding the first event to a task ctx; this is tricky because we cannot
187 * rely on ctx->is_active and therefore cannot use event_function_call().
188 * See perf_install_in_context().
190 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
193 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
194 struct perf_event_context *, void *);
196 struct event_function_struct {
197 struct perf_event *event;
202 static int event_function(void *info)
204 struct event_function_struct *efs = info;
205 struct perf_event *event = efs->event;
206 struct perf_event_context *ctx = event->ctx;
207 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
208 struct perf_event_context *task_ctx = cpuctx->task_ctx;
211 lockdep_assert_irqs_disabled();
213 perf_ctx_lock(cpuctx, task_ctx);
215 * Since we do the IPI call without holding ctx->lock things can have
216 * changed, double check we hit the task we set out to hit.
219 if (ctx->task != current) {
225 * We only use event_function_call() on established contexts,
226 * and event_function() is only ever called when active (or
227 * rather, we'll have bailed in task_function_call() or the
228 * above ctx->task != current test), therefore we must have
229 * ctx->is_active here.
231 WARN_ON_ONCE(!ctx->is_active);
233 * And since we have ctx->is_active, cpuctx->task_ctx must
236 WARN_ON_ONCE(task_ctx != ctx);
238 WARN_ON_ONCE(&cpuctx->ctx != ctx);
241 efs->func(event, cpuctx, ctx, efs->data);
243 perf_ctx_unlock(cpuctx, task_ctx);
248 static void event_function_call(struct perf_event *event, event_f func, void *data)
250 struct perf_event_context *ctx = event->ctx;
251 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
252 struct event_function_struct efs = {
258 if (!event->parent) {
260 * If this is a !child event, we must hold ctx::mutex to
261 * stabilize the the event->ctx relation. See
262 * perf_event_ctx_lock().
264 lockdep_assert_held(&ctx->mutex);
268 cpu_function_call(event->cpu, event_function, &efs);
272 if (task == TASK_TOMBSTONE)
276 if (!task_function_call(task, event_function, &efs))
279 raw_spin_lock_irq(&ctx->lock);
281 * Reload the task pointer, it might have been changed by
282 * a concurrent perf_event_context_sched_out().
285 if (task == TASK_TOMBSTONE) {
286 raw_spin_unlock_irq(&ctx->lock);
289 if (ctx->is_active) {
290 raw_spin_unlock_irq(&ctx->lock);
293 func(event, NULL, ctx, data);
294 raw_spin_unlock_irq(&ctx->lock);
298 * Similar to event_function_call() + event_function(), but hard assumes IRQs
299 * are already disabled and we're on the right CPU.
301 static void event_function_local(struct perf_event *event, event_f func, void *data)
303 struct perf_event_context *ctx = event->ctx;
304 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
305 struct task_struct *task = READ_ONCE(ctx->task);
306 struct perf_event_context *task_ctx = NULL;
308 lockdep_assert_irqs_disabled();
311 if (task == TASK_TOMBSTONE)
317 perf_ctx_lock(cpuctx, task_ctx);
320 if (task == TASK_TOMBSTONE)
325 * We must be either inactive or active and the right task,
326 * otherwise we're screwed, since we cannot IPI to somewhere
329 if (ctx->is_active) {
330 if (WARN_ON_ONCE(task != current))
333 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
337 WARN_ON_ONCE(&cpuctx->ctx != ctx);
340 func(event, cpuctx, ctx, data);
342 perf_ctx_unlock(cpuctx, task_ctx);
345 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
346 PERF_FLAG_FD_OUTPUT |\
347 PERF_FLAG_PID_CGROUP |\
348 PERF_FLAG_FD_CLOEXEC)
351 * branch priv levels that need permission checks
353 #define PERF_SAMPLE_BRANCH_PERM_PLM \
354 (PERF_SAMPLE_BRANCH_KERNEL |\
355 PERF_SAMPLE_BRANCH_HV)
358 EVENT_FLEXIBLE = 0x1,
361 /* see ctx_resched() for details */
363 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
367 * perf_sched_events : >0 events exist
368 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
371 static void perf_sched_delayed(struct work_struct *work);
372 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
373 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
374 static DEFINE_MUTEX(perf_sched_mutex);
375 static atomic_t perf_sched_count;
377 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
378 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
379 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
381 static atomic_t nr_mmap_events __read_mostly;
382 static atomic_t nr_comm_events __read_mostly;
383 static atomic_t nr_namespaces_events __read_mostly;
384 static atomic_t nr_task_events __read_mostly;
385 static atomic_t nr_freq_events __read_mostly;
386 static atomic_t nr_switch_events __read_mostly;
387 static atomic_t nr_ksymbol_events __read_mostly;
388 static atomic_t nr_bpf_events __read_mostly;
390 static LIST_HEAD(pmus);
391 static DEFINE_MUTEX(pmus_lock);
392 static struct srcu_struct pmus_srcu;
393 static cpumask_var_t perf_online_mask;
396 * perf event paranoia level:
397 * -1 - not paranoid at all
398 * 0 - disallow raw tracepoint access for unpriv
399 * 1 - disallow cpu events for unpriv
400 * 2 - disallow kernel profiling for unpriv
402 int sysctl_perf_event_paranoid __read_mostly = 2;
404 /* Minimum for 512 kiB + 1 user control page */
405 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
408 * max perf event sample rate
410 #define DEFAULT_MAX_SAMPLE_RATE 100000
411 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
412 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
414 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
416 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
417 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
419 static int perf_sample_allowed_ns __read_mostly =
420 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
422 static void update_perf_cpu_limits(void)
424 u64 tmp = perf_sample_period_ns;
426 tmp *= sysctl_perf_cpu_time_max_percent;
427 tmp = div_u64(tmp, 100);
431 WRITE_ONCE(perf_sample_allowed_ns, tmp);
434 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
436 int perf_proc_update_handler(struct ctl_table *table, int write,
437 void __user *buffer, size_t *lenp,
441 int perf_cpu = sysctl_perf_cpu_time_max_percent;
443 * If throttling is disabled don't allow the write:
445 if (write && (perf_cpu == 100 || perf_cpu == 0))
448 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
452 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
453 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
454 update_perf_cpu_limits();
459 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
461 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
462 void __user *buffer, size_t *lenp,
465 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
470 if (sysctl_perf_cpu_time_max_percent == 100 ||
471 sysctl_perf_cpu_time_max_percent == 0) {
473 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
474 WRITE_ONCE(perf_sample_allowed_ns, 0);
476 update_perf_cpu_limits();
483 * perf samples are done in some very critical code paths (NMIs).
484 * If they take too much CPU time, the system can lock up and not
485 * get any real work done. This will drop the sample rate when
486 * we detect that events are taking too long.
488 #define NR_ACCUMULATED_SAMPLES 128
489 static DEFINE_PER_CPU(u64, running_sample_length);
491 static u64 __report_avg;
492 static u64 __report_allowed;
494 static void perf_duration_warn(struct irq_work *w)
496 printk_ratelimited(KERN_INFO
497 "perf: interrupt took too long (%lld > %lld), lowering "
498 "kernel.perf_event_max_sample_rate to %d\n",
499 __report_avg, __report_allowed,
500 sysctl_perf_event_sample_rate);
503 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
505 void perf_sample_event_took(u64 sample_len_ns)
507 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
515 /* Decay the counter by 1 average sample. */
516 running_len = __this_cpu_read(running_sample_length);
517 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
518 running_len += sample_len_ns;
519 __this_cpu_write(running_sample_length, running_len);
522 * Note: this will be biased artifically low until we have
523 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
524 * from having to maintain a count.
526 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
527 if (avg_len <= max_len)
530 __report_avg = avg_len;
531 __report_allowed = max_len;
534 * Compute a throttle threshold 25% below the current duration.
536 avg_len += avg_len / 4;
537 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
543 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
544 WRITE_ONCE(max_samples_per_tick, max);
546 sysctl_perf_event_sample_rate = max * HZ;
547 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
549 if (!irq_work_queue(&perf_duration_work)) {
550 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
551 "kernel.perf_event_max_sample_rate to %d\n",
552 __report_avg, __report_allowed,
553 sysctl_perf_event_sample_rate);
557 static atomic64_t perf_event_id;
559 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
560 enum event_type_t event_type);
562 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
563 enum event_type_t event_type,
564 struct task_struct *task);
566 static void update_context_time(struct perf_event_context *ctx);
567 static u64 perf_event_time(struct perf_event *event);
569 void __weak perf_event_print_debug(void) { }
571 extern __weak const char *perf_pmu_name(void)
576 static inline u64 perf_clock(void)
578 return local_clock();
581 static inline u64 perf_event_clock(struct perf_event *event)
583 return event->clock();
587 * State based event timekeeping...
589 * The basic idea is to use event->state to determine which (if any) time
590 * fields to increment with the current delta. This means we only need to
591 * update timestamps when we change state or when they are explicitly requested
594 * Event groups make things a little more complicated, but not terribly so. The
595 * rules for a group are that if the group leader is OFF the entire group is
596 * OFF, irrespecive of what the group member states are. This results in
597 * __perf_effective_state().
599 * A futher ramification is that when a group leader flips between OFF and
600 * !OFF, we need to update all group member times.
603 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
604 * need to make sure the relevant context time is updated before we try and
605 * update our timestamps.
608 static __always_inline enum perf_event_state
609 __perf_effective_state(struct perf_event *event)
611 struct perf_event *leader = event->group_leader;
613 if (leader->state <= PERF_EVENT_STATE_OFF)
614 return leader->state;
619 static __always_inline void
620 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
622 enum perf_event_state state = __perf_effective_state(event);
623 u64 delta = now - event->tstamp;
625 *enabled = event->total_time_enabled;
626 if (state >= PERF_EVENT_STATE_INACTIVE)
629 *running = event->total_time_running;
630 if (state >= PERF_EVENT_STATE_ACTIVE)
634 static void perf_event_update_time(struct perf_event *event)
636 u64 now = perf_event_time(event);
638 __perf_update_times(event, now, &event->total_time_enabled,
639 &event->total_time_running);
643 static void perf_event_update_sibling_time(struct perf_event *leader)
645 struct perf_event *sibling;
647 for_each_sibling_event(sibling, leader)
648 perf_event_update_time(sibling);
652 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
654 if (event->state == state)
657 perf_event_update_time(event);
659 * If a group leader gets enabled/disabled all its siblings
662 if ((event->state < 0) ^ (state < 0))
663 perf_event_update_sibling_time(event);
665 WRITE_ONCE(event->state, state);
668 #ifdef CONFIG_CGROUP_PERF
671 perf_cgroup_match(struct perf_event *event)
673 struct perf_event_context *ctx = event->ctx;
674 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
676 /* @event doesn't care about cgroup */
680 /* wants specific cgroup scope but @cpuctx isn't associated with any */
685 * Cgroup scoping is recursive. An event enabled for a cgroup is
686 * also enabled for all its descendant cgroups. If @cpuctx's
687 * cgroup is a descendant of @event's (the test covers identity
688 * case), it's a match.
690 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
691 event->cgrp->css.cgroup);
694 static inline void perf_detach_cgroup(struct perf_event *event)
696 css_put(&event->cgrp->css);
700 static inline int is_cgroup_event(struct perf_event *event)
702 return event->cgrp != NULL;
705 static inline u64 perf_cgroup_event_time(struct perf_event *event)
707 struct perf_cgroup_info *t;
709 t = per_cpu_ptr(event->cgrp->info, event->cpu);
713 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
715 struct perf_cgroup_info *info;
720 info = this_cpu_ptr(cgrp->info);
722 info->time += now - info->timestamp;
723 info->timestamp = now;
726 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
728 struct perf_cgroup *cgrp = cpuctx->cgrp;
729 struct cgroup_subsys_state *css;
732 for (css = &cgrp->css; css; css = css->parent) {
733 cgrp = container_of(css, struct perf_cgroup, css);
734 __update_cgrp_time(cgrp);
739 static inline void update_cgrp_time_from_event(struct perf_event *event)
741 struct perf_cgroup *cgrp;
744 * ensure we access cgroup data only when needed and
745 * when we know the cgroup is pinned (css_get)
747 if (!is_cgroup_event(event))
750 cgrp = perf_cgroup_from_task(current, event->ctx);
752 * Do not update time when cgroup is not active
754 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
755 __update_cgrp_time(event->cgrp);
759 perf_cgroup_set_timestamp(struct task_struct *task,
760 struct perf_event_context *ctx)
762 struct perf_cgroup *cgrp;
763 struct perf_cgroup_info *info;
764 struct cgroup_subsys_state *css;
767 * ctx->lock held by caller
768 * ensure we do not access cgroup data
769 * unless we have the cgroup pinned (css_get)
771 if (!task || !ctx->nr_cgroups)
774 cgrp = perf_cgroup_from_task(task, ctx);
776 for (css = &cgrp->css; css; css = css->parent) {
777 cgrp = container_of(css, struct perf_cgroup, css);
778 info = this_cpu_ptr(cgrp->info);
779 info->timestamp = ctx->timestamp;
783 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
785 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
786 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
789 * reschedule events based on the cgroup constraint of task.
791 * mode SWOUT : schedule out everything
792 * mode SWIN : schedule in based on cgroup for next
794 static void perf_cgroup_switch(struct task_struct *task, int mode)
796 struct perf_cpu_context *cpuctx;
797 struct list_head *list;
801 * Disable interrupts and preemption to avoid this CPU's
802 * cgrp_cpuctx_entry to change under us.
804 local_irq_save(flags);
806 list = this_cpu_ptr(&cgrp_cpuctx_list);
807 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
808 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
810 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
811 perf_pmu_disable(cpuctx->ctx.pmu);
813 if (mode & PERF_CGROUP_SWOUT) {
814 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
816 * must not be done before ctxswout due
817 * to event_filter_match() in event_sched_out()
822 if (mode & PERF_CGROUP_SWIN) {
823 WARN_ON_ONCE(cpuctx->cgrp);
825 * set cgrp before ctxsw in to allow
826 * event_filter_match() to not have to pass
828 * we pass the cpuctx->ctx to perf_cgroup_from_task()
829 * because cgorup events are only per-cpu
831 cpuctx->cgrp = perf_cgroup_from_task(task,
833 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
835 perf_pmu_enable(cpuctx->ctx.pmu);
836 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
839 local_irq_restore(flags);
842 static inline void perf_cgroup_sched_out(struct task_struct *task,
843 struct task_struct *next)
845 struct perf_cgroup *cgrp1;
846 struct perf_cgroup *cgrp2 = NULL;
850 * we come here when we know perf_cgroup_events > 0
851 * we do not need to pass the ctx here because we know
852 * we are holding the rcu lock
854 cgrp1 = perf_cgroup_from_task(task, NULL);
855 cgrp2 = perf_cgroup_from_task(next, NULL);
858 * only schedule out current cgroup events if we know
859 * that we are switching to a different cgroup. Otherwise,
860 * do no touch the cgroup events.
863 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
868 static inline void perf_cgroup_sched_in(struct task_struct *prev,
869 struct task_struct *task)
871 struct perf_cgroup *cgrp1;
872 struct perf_cgroup *cgrp2 = NULL;
876 * we come here when we know perf_cgroup_events > 0
877 * we do not need to pass the ctx here because we know
878 * we are holding the rcu lock
880 cgrp1 = perf_cgroup_from_task(task, NULL);
881 cgrp2 = perf_cgroup_from_task(prev, NULL);
884 * only need to schedule in cgroup events if we are changing
885 * cgroup during ctxsw. Cgroup events were not scheduled
886 * out of ctxsw out if that was not the case.
889 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
894 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
895 struct perf_event_attr *attr,
896 struct perf_event *group_leader)
898 struct perf_cgroup *cgrp;
899 struct cgroup_subsys_state *css;
900 struct fd f = fdget(fd);
906 css = css_tryget_online_from_dir(f.file->f_path.dentry,
907 &perf_event_cgrp_subsys);
913 cgrp = container_of(css, struct perf_cgroup, css);
917 * all events in a group must monitor
918 * the same cgroup because a task belongs
919 * to only one perf cgroup at a time
921 if (group_leader && group_leader->cgrp != cgrp) {
922 perf_detach_cgroup(event);
931 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
933 struct perf_cgroup_info *t;
934 t = per_cpu_ptr(event->cgrp->info, event->cpu);
935 event->shadow_ctx_time = now - t->timestamp;
939 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
940 * cleared when last cgroup event is removed.
943 list_update_cgroup_event(struct perf_event *event,
944 struct perf_event_context *ctx, bool add)
946 struct perf_cpu_context *cpuctx;
947 struct list_head *cpuctx_entry;
949 if (!is_cgroup_event(event))
953 * Because cgroup events are always per-cpu events,
954 * this will always be called from the right CPU.
956 cpuctx = __get_cpu_context(ctx);
959 * Since setting cpuctx->cgrp is conditional on the current @cgrp
960 * matching the event's cgroup, we must do this for every new event,
961 * because if the first would mismatch, the second would not try again
962 * and we would leave cpuctx->cgrp unset.
964 if (add && !cpuctx->cgrp) {
965 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
967 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
971 if (add && ctx->nr_cgroups++)
973 else if (!add && --ctx->nr_cgroups)
976 /* no cgroup running */
980 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
982 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
984 list_del(cpuctx_entry);
987 #else /* !CONFIG_CGROUP_PERF */
990 perf_cgroup_match(struct perf_event *event)
995 static inline void perf_detach_cgroup(struct perf_event *event)
998 static inline int is_cgroup_event(struct perf_event *event)
1003 static inline void update_cgrp_time_from_event(struct perf_event *event)
1007 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1011 static inline void perf_cgroup_sched_out(struct task_struct *task,
1012 struct task_struct *next)
1016 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1017 struct task_struct *task)
1021 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1022 struct perf_event_attr *attr,
1023 struct perf_event *group_leader)
1029 perf_cgroup_set_timestamp(struct task_struct *task,
1030 struct perf_event_context *ctx)
1035 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1040 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1044 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1050 list_update_cgroup_event(struct perf_event *event,
1051 struct perf_event_context *ctx, bool add)
1058 * set default to be dependent on timer tick just
1059 * like original code
1061 #define PERF_CPU_HRTIMER (1000 / HZ)
1063 * function must be called with interrupts disabled
1065 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1067 struct perf_cpu_context *cpuctx;
1070 lockdep_assert_irqs_disabled();
1072 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1073 rotations = perf_rotate_context(cpuctx);
1075 raw_spin_lock(&cpuctx->hrtimer_lock);
1077 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1079 cpuctx->hrtimer_active = 0;
1080 raw_spin_unlock(&cpuctx->hrtimer_lock);
1082 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1085 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1087 struct hrtimer *timer = &cpuctx->hrtimer;
1088 struct pmu *pmu = cpuctx->ctx.pmu;
1091 /* no multiplexing needed for SW PMU */
1092 if (pmu->task_ctx_nr == perf_sw_context)
1096 * check default is sane, if not set then force to
1097 * default interval (1/tick)
1099 interval = pmu->hrtimer_interval_ms;
1101 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1103 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1105 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1106 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1107 timer->function = perf_mux_hrtimer_handler;
1110 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1112 struct hrtimer *timer = &cpuctx->hrtimer;
1113 struct pmu *pmu = cpuctx->ctx.pmu;
1114 unsigned long flags;
1116 /* not for SW PMU */
1117 if (pmu->task_ctx_nr == perf_sw_context)
1120 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1121 if (!cpuctx->hrtimer_active) {
1122 cpuctx->hrtimer_active = 1;
1123 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1124 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1126 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1131 void perf_pmu_disable(struct pmu *pmu)
1133 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1135 pmu->pmu_disable(pmu);
1138 void perf_pmu_enable(struct pmu *pmu)
1140 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1142 pmu->pmu_enable(pmu);
1145 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1148 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1149 * perf_event_task_tick() are fully serialized because they're strictly cpu
1150 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1151 * disabled, while perf_event_task_tick is called from IRQ context.
1153 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1155 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1157 lockdep_assert_irqs_disabled();
1159 WARN_ON(!list_empty(&ctx->active_ctx_list));
1161 list_add(&ctx->active_ctx_list, head);
1164 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1166 lockdep_assert_irqs_disabled();
1168 WARN_ON(list_empty(&ctx->active_ctx_list));
1170 list_del_init(&ctx->active_ctx_list);
1173 static void get_ctx(struct perf_event_context *ctx)
1175 refcount_inc(&ctx->refcount);
1178 static void free_ctx(struct rcu_head *head)
1180 struct perf_event_context *ctx;
1182 ctx = container_of(head, struct perf_event_context, rcu_head);
1183 kfree(ctx->task_ctx_data);
1187 static void put_ctx(struct perf_event_context *ctx)
1189 if (refcount_dec_and_test(&ctx->refcount)) {
1190 if (ctx->parent_ctx)
1191 put_ctx(ctx->parent_ctx);
1192 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1193 put_task_struct(ctx->task);
1194 call_rcu(&ctx->rcu_head, free_ctx);
1199 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1200 * perf_pmu_migrate_context() we need some magic.
1202 * Those places that change perf_event::ctx will hold both
1203 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1205 * Lock ordering is by mutex address. There are two other sites where
1206 * perf_event_context::mutex nests and those are:
1208 * - perf_event_exit_task_context() [ child , 0 ]
1209 * perf_event_exit_event()
1210 * put_event() [ parent, 1 ]
1212 * - perf_event_init_context() [ parent, 0 ]
1213 * inherit_task_group()
1216 * perf_event_alloc()
1218 * perf_try_init_event() [ child , 1 ]
1220 * While it appears there is an obvious deadlock here -- the parent and child
1221 * nesting levels are inverted between the two. This is in fact safe because
1222 * life-time rules separate them. That is an exiting task cannot fork, and a
1223 * spawning task cannot (yet) exit.
1225 * But remember that that these are parent<->child context relations, and
1226 * migration does not affect children, therefore these two orderings should not
1229 * The change in perf_event::ctx does not affect children (as claimed above)
1230 * because the sys_perf_event_open() case will install a new event and break
1231 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1232 * concerned with cpuctx and that doesn't have children.
1234 * The places that change perf_event::ctx will issue:
1236 * perf_remove_from_context();
1237 * synchronize_rcu();
1238 * perf_install_in_context();
1240 * to affect the change. The remove_from_context() + synchronize_rcu() should
1241 * quiesce the event, after which we can install it in the new location. This
1242 * means that only external vectors (perf_fops, prctl) can perturb the event
1243 * while in transit. Therefore all such accessors should also acquire
1244 * perf_event_context::mutex to serialize against this.
1246 * However; because event->ctx can change while we're waiting to acquire
1247 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1252 * task_struct::perf_event_mutex
1253 * perf_event_context::mutex
1254 * perf_event::child_mutex;
1255 * perf_event_context::lock
1256 * perf_event::mmap_mutex
1258 * perf_addr_filters_head::lock
1262 * cpuctx->mutex / perf_event_context::mutex
1264 static struct perf_event_context *
1265 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1267 struct perf_event_context *ctx;
1271 ctx = READ_ONCE(event->ctx);
1272 if (!refcount_inc_not_zero(&ctx->refcount)) {
1278 mutex_lock_nested(&ctx->mutex, nesting);
1279 if (event->ctx != ctx) {
1280 mutex_unlock(&ctx->mutex);
1288 static inline struct perf_event_context *
1289 perf_event_ctx_lock(struct perf_event *event)
1291 return perf_event_ctx_lock_nested(event, 0);
1294 static void perf_event_ctx_unlock(struct perf_event *event,
1295 struct perf_event_context *ctx)
1297 mutex_unlock(&ctx->mutex);
1302 * This must be done under the ctx->lock, such as to serialize against
1303 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1304 * calling scheduler related locks and ctx->lock nests inside those.
1306 static __must_check struct perf_event_context *
1307 unclone_ctx(struct perf_event_context *ctx)
1309 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1311 lockdep_assert_held(&ctx->lock);
1314 ctx->parent_ctx = NULL;
1320 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1325 * only top level events have the pid namespace they were created in
1328 event = event->parent;
1330 nr = __task_pid_nr_ns(p, type, event->ns);
1331 /* avoid -1 if it is idle thread or runs in another ns */
1332 if (!nr && !pid_alive(p))
1337 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1339 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1342 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1344 return perf_event_pid_type(event, p, PIDTYPE_PID);
1348 * If we inherit events we want to return the parent event id
1351 static u64 primary_event_id(struct perf_event *event)
1356 id = event->parent->id;
1362 * Get the perf_event_context for a task and lock it.
1364 * This has to cope with with the fact that until it is locked,
1365 * the context could get moved to another task.
1367 static struct perf_event_context *
1368 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1370 struct perf_event_context *ctx;
1374 * One of the few rules of preemptible RCU is that one cannot do
1375 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1376 * part of the read side critical section was irqs-enabled -- see
1377 * rcu_read_unlock_special().
1379 * Since ctx->lock nests under rq->lock we must ensure the entire read
1380 * side critical section has interrupts disabled.
1382 local_irq_save(*flags);
1384 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1387 * If this context is a clone of another, it might
1388 * get swapped for another underneath us by
1389 * perf_event_task_sched_out, though the
1390 * rcu_read_lock() protects us from any context
1391 * getting freed. Lock the context and check if it
1392 * got swapped before we could get the lock, and retry
1393 * if so. If we locked the right context, then it
1394 * can't get swapped on us any more.
1396 raw_spin_lock(&ctx->lock);
1397 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1398 raw_spin_unlock(&ctx->lock);
1400 local_irq_restore(*flags);
1404 if (ctx->task == TASK_TOMBSTONE ||
1405 !refcount_inc_not_zero(&ctx->refcount)) {
1406 raw_spin_unlock(&ctx->lock);
1409 WARN_ON_ONCE(ctx->task != task);
1414 local_irq_restore(*flags);
1419 * Get the context for a task and increment its pin_count so it
1420 * can't get swapped to another task. This also increments its
1421 * reference count so that the context can't get freed.
1423 static struct perf_event_context *
1424 perf_pin_task_context(struct task_struct *task, int ctxn)
1426 struct perf_event_context *ctx;
1427 unsigned long flags;
1429 ctx = perf_lock_task_context(task, ctxn, &flags);
1432 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1437 static void perf_unpin_context(struct perf_event_context *ctx)
1439 unsigned long flags;
1441 raw_spin_lock_irqsave(&ctx->lock, flags);
1443 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1447 * Update the record of the current time in a context.
1449 static void update_context_time(struct perf_event_context *ctx)
1451 u64 now = perf_clock();
1453 ctx->time += now - ctx->timestamp;
1454 ctx->timestamp = now;
1457 static u64 perf_event_time(struct perf_event *event)
1459 struct perf_event_context *ctx = event->ctx;
1461 if (is_cgroup_event(event))
1462 return perf_cgroup_event_time(event);
1464 return ctx ? ctx->time : 0;
1467 static enum event_type_t get_event_type(struct perf_event *event)
1469 struct perf_event_context *ctx = event->ctx;
1470 enum event_type_t event_type;
1472 lockdep_assert_held(&ctx->lock);
1475 * It's 'group type', really, because if our group leader is
1476 * pinned, so are we.
1478 if (event->group_leader != event)
1479 event = event->group_leader;
1481 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1483 event_type |= EVENT_CPU;
1489 * Helper function to initialize event group nodes.
1491 static void init_event_group(struct perf_event *event)
1493 RB_CLEAR_NODE(&event->group_node);
1494 event->group_index = 0;
1498 * Extract pinned or flexible groups from the context
1499 * based on event attrs bits.
1501 static struct perf_event_groups *
1502 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1504 if (event->attr.pinned)
1505 return &ctx->pinned_groups;
1507 return &ctx->flexible_groups;
1511 * Helper function to initializes perf_event_group trees.
1513 static void perf_event_groups_init(struct perf_event_groups *groups)
1515 groups->tree = RB_ROOT;
1520 * Compare function for event groups;
1522 * Implements complex key that first sorts by CPU and then by virtual index
1523 * which provides ordering when rotating groups for the same CPU.
1526 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1528 if (left->cpu < right->cpu)
1530 if (left->cpu > right->cpu)
1533 if (left->group_index < right->group_index)
1535 if (left->group_index > right->group_index)
1542 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1543 * key (see perf_event_groups_less). This places it last inside the CPU
1547 perf_event_groups_insert(struct perf_event_groups *groups,
1548 struct perf_event *event)
1550 struct perf_event *node_event;
1551 struct rb_node *parent;
1552 struct rb_node **node;
1554 event->group_index = ++groups->index;
1556 node = &groups->tree.rb_node;
1561 node_event = container_of(*node, struct perf_event, group_node);
1563 if (perf_event_groups_less(event, node_event))
1564 node = &parent->rb_left;
1566 node = &parent->rb_right;
1569 rb_link_node(&event->group_node, parent, node);
1570 rb_insert_color(&event->group_node, &groups->tree);
1574 * Helper function to insert event into the pinned or flexible groups.
1577 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1579 struct perf_event_groups *groups;
1581 groups = get_event_groups(event, ctx);
1582 perf_event_groups_insert(groups, event);
1586 * Delete a group from a tree.
1589 perf_event_groups_delete(struct perf_event_groups *groups,
1590 struct perf_event *event)
1592 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1593 RB_EMPTY_ROOT(&groups->tree));
1595 rb_erase(&event->group_node, &groups->tree);
1596 init_event_group(event);
1600 * Helper function to delete event from its groups.
1603 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1605 struct perf_event_groups *groups;
1607 groups = get_event_groups(event, ctx);
1608 perf_event_groups_delete(groups, event);
1612 * Get the leftmost event in the @cpu subtree.
1614 static struct perf_event *
1615 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1617 struct perf_event *node_event = NULL, *match = NULL;
1618 struct rb_node *node = groups->tree.rb_node;
1621 node_event = container_of(node, struct perf_event, group_node);
1623 if (cpu < node_event->cpu) {
1624 node = node->rb_left;
1625 } else if (cpu > node_event->cpu) {
1626 node = node->rb_right;
1629 node = node->rb_left;
1637 * Like rb_entry_next_safe() for the @cpu subtree.
1639 static struct perf_event *
1640 perf_event_groups_next(struct perf_event *event)
1642 struct perf_event *next;
1644 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1645 if (next && next->cpu == event->cpu)
1652 * Iterate through the whole groups tree.
1654 #define perf_event_groups_for_each(event, groups) \
1655 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1656 typeof(*event), group_node); event; \
1657 event = rb_entry_safe(rb_next(&event->group_node), \
1658 typeof(*event), group_node))
1661 * Add an event from the lists for its context.
1662 * Must be called with ctx->mutex and ctx->lock held.
1665 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1667 lockdep_assert_held(&ctx->lock);
1669 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1670 event->attach_state |= PERF_ATTACH_CONTEXT;
1672 event->tstamp = perf_event_time(event);
1675 * If we're a stand alone event or group leader, we go to the context
1676 * list, group events are kept attached to the group so that
1677 * perf_group_detach can, at all times, locate all siblings.
1679 if (event->group_leader == event) {
1680 event->group_caps = event->event_caps;
1681 add_event_to_groups(event, ctx);
1684 list_update_cgroup_event(event, ctx, true);
1686 list_add_rcu(&event->event_entry, &ctx->event_list);
1688 if (event->attr.inherit_stat)
1695 * Initialize event state based on the perf_event_attr::disabled.
1697 static inline void perf_event__state_init(struct perf_event *event)
1699 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1700 PERF_EVENT_STATE_INACTIVE;
1703 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1705 int entry = sizeof(u64); /* value */
1709 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1710 size += sizeof(u64);
1712 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1713 size += sizeof(u64);
1715 if (event->attr.read_format & PERF_FORMAT_ID)
1716 entry += sizeof(u64);
1718 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1720 size += sizeof(u64);
1724 event->read_size = size;
1727 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1729 struct perf_sample_data *data;
1732 if (sample_type & PERF_SAMPLE_IP)
1733 size += sizeof(data->ip);
1735 if (sample_type & PERF_SAMPLE_ADDR)
1736 size += sizeof(data->addr);
1738 if (sample_type & PERF_SAMPLE_PERIOD)
1739 size += sizeof(data->period);
1741 if (sample_type & PERF_SAMPLE_WEIGHT)
1742 size += sizeof(data->weight);
1744 if (sample_type & PERF_SAMPLE_READ)
1745 size += event->read_size;
1747 if (sample_type & PERF_SAMPLE_DATA_SRC)
1748 size += sizeof(data->data_src.val);
1750 if (sample_type & PERF_SAMPLE_TRANSACTION)
1751 size += sizeof(data->txn);
1753 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1754 size += sizeof(data->phys_addr);
1756 event->header_size = size;
1760 * Called at perf_event creation and when events are attached/detached from a
1763 static void perf_event__header_size(struct perf_event *event)
1765 __perf_event_read_size(event,
1766 event->group_leader->nr_siblings);
1767 __perf_event_header_size(event, event->attr.sample_type);
1770 static void perf_event__id_header_size(struct perf_event *event)
1772 struct perf_sample_data *data;
1773 u64 sample_type = event->attr.sample_type;
1776 if (sample_type & PERF_SAMPLE_TID)
1777 size += sizeof(data->tid_entry);
1779 if (sample_type & PERF_SAMPLE_TIME)
1780 size += sizeof(data->time);
1782 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1783 size += sizeof(data->id);
1785 if (sample_type & PERF_SAMPLE_ID)
1786 size += sizeof(data->id);
1788 if (sample_type & PERF_SAMPLE_STREAM_ID)
1789 size += sizeof(data->stream_id);
1791 if (sample_type & PERF_SAMPLE_CPU)
1792 size += sizeof(data->cpu_entry);
1794 event->id_header_size = size;
1797 static bool perf_event_validate_size(struct perf_event *event)
1800 * The values computed here will be over-written when we actually
1803 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1804 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1805 perf_event__id_header_size(event);
1808 * Sum the lot; should not exceed the 64k limit we have on records.
1809 * Conservative limit to allow for callchains and other variable fields.
1811 if (event->read_size + event->header_size +
1812 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1818 static void perf_group_attach(struct perf_event *event)
1820 struct perf_event *group_leader = event->group_leader, *pos;
1822 lockdep_assert_held(&event->ctx->lock);
1825 * We can have double attach due to group movement in perf_event_open.
1827 if (event->attach_state & PERF_ATTACH_GROUP)
1830 event->attach_state |= PERF_ATTACH_GROUP;
1832 if (group_leader == event)
1835 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1837 group_leader->group_caps &= event->event_caps;
1839 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1840 group_leader->nr_siblings++;
1842 perf_event__header_size(group_leader);
1844 for_each_sibling_event(pos, group_leader)
1845 perf_event__header_size(pos);
1849 * Remove an event from the lists for its context.
1850 * Must be called with ctx->mutex and ctx->lock held.
1853 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1855 WARN_ON_ONCE(event->ctx != ctx);
1856 lockdep_assert_held(&ctx->lock);
1859 * We can have double detach due to exit/hot-unplug + close.
1861 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1864 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1866 list_update_cgroup_event(event, ctx, false);
1869 if (event->attr.inherit_stat)
1872 list_del_rcu(&event->event_entry);
1874 if (event->group_leader == event)
1875 del_event_from_groups(event, ctx);
1878 * If event was in error state, then keep it
1879 * that way, otherwise bogus counts will be
1880 * returned on read(). The only way to get out
1881 * of error state is by explicit re-enabling
1884 if (event->state > PERF_EVENT_STATE_OFF)
1885 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1891 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
1893 if (!has_aux(aux_event))
1896 if (!event->pmu->aux_output_match)
1899 return event->pmu->aux_output_match(aux_event);
1902 static void put_event(struct perf_event *event);
1903 static void event_sched_out(struct perf_event *event,
1904 struct perf_cpu_context *cpuctx,
1905 struct perf_event_context *ctx);
1907 static void perf_put_aux_event(struct perf_event *event)
1909 struct perf_event_context *ctx = event->ctx;
1910 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1911 struct perf_event *iter;
1914 * If event uses aux_event tear down the link
1916 if (event->aux_event) {
1917 iter = event->aux_event;
1918 event->aux_event = NULL;
1924 * If the event is an aux_event, tear down all links to
1925 * it from other events.
1927 for_each_sibling_event(iter, event->group_leader) {
1928 if (iter->aux_event != event)
1931 iter->aux_event = NULL;
1935 * If it's ACTIVE, schedule it out and put it into ERROR
1936 * state so that we don't try to schedule it again. Note
1937 * that perf_event_enable() will clear the ERROR status.
1939 event_sched_out(iter, cpuctx, ctx);
1940 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
1944 static bool perf_need_aux_event(struct perf_event *event)
1946 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
1949 static int perf_get_aux_event(struct perf_event *event,
1950 struct perf_event *group_leader)
1953 * Our group leader must be an aux event if we want to be
1954 * an aux_output. This way, the aux event will precede its
1955 * aux_output events in the group, and therefore will always
1962 * aux_output and aux_sample_size are mutually exclusive.
1964 if (event->attr.aux_output && event->attr.aux_sample_size)
1967 if (event->attr.aux_output &&
1968 !perf_aux_output_match(event, group_leader))
1971 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
1974 if (!atomic_long_inc_not_zero(&group_leader->refcount))
1978 * Link aux_outputs to their aux event; this is undone in
1979 * perf_group_detach() by perf_put_aux_event(). When the
1980 * group in torn down, the aux_output events loose their
1981 * link to the aux_event and can't schedule any more.
1983 event->aux_event = group_leader;
1988 static void perf_group_detach(struct perf_event *event)
1990 struct perf_event *sibling, *tmp;
1991 struct perf_event_context *ctx = event->ctx;
1993 lockdep_assert_held(&ctx->lock);
1996 * We can have double detach due to exit/hot-unplug + close.
1998 if (!(event->attach_state & PERF_ATTACH_GROUP))
2001 event->attach_state &= ~PERF_ATTACH_GROUP;
2003 perf_put_aux_event(event);
2006 * If this is a sibling, remove it from its group.
2008 if (event->group_leader != event) {
2009 list_del_init(&event->sibling_list);
2010 event->group_leader->nr_siblings--;
2015 * If this was a group event with sibling events then
2016 * upgrade the siblings to singleton events by adding them
2017 * to whatever list we are on.
2019 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2021 sibling->group_leader = sibling;
2022 list_del_init(&sibling->sibling_list);
2024 /* Inherit group flags from the previous leader */
2025 sibling->group_caps = event->group_caps;
2027 if (!RB_EMPTY_NODE(&event->group_node)) {
2028 add_event_to_groups(sibling, event->ctx);
2030 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
2031 struct list_head *list = sibling->attr.pinned ?
2032 &ctx->pinned_active : &ctx->flexible_active;
2034 list_add_tail(&sibling->active_list, list);
2038 WARN_ON_ONCE(sibling->ctx != event->ctx);
2042 perf_event__header_size(event->group_leader);
2044 for_each_sibling_event(tmp, event->group_leader)
2045 perf_event__header_size(tmp);
2048 static bool is_orphaned_event(struct perf_event *event)
2050 return event->state == PERF_EVENT_STATE_DEAD;
2053 static inline int __pmu_filter_match(struct perf_event *event)
2055 struct pmu *pmu = event->pmu;
2056 return pmu->filter_match ? pmu->filter_match(event) : 1;
2060 * Check whether we should attempt to schedule an event group based on
2061 * PMU-specific filtering. An event group can consist of HW and SW events,
2062 * potentially with a SW leader, so we must check all the filters, to
2063 * determine whether a group is schedulable:
2065 static inline int pmu_filter_match(struct perf_event *event)
2067 struct perf_event *sibling;
2069 if (!__pmu_filter_match(event))
2072 for_each_sibling_event(sibling, event) {
2073 if (!__pmu_filter_match(sibling))
2081 event_filter_match(struct perf_event *event)
2083 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2084 perf_cgroup_match(event) && pmu_filter_match(event);
2088 event_sched_out(struct perf_event *event,
2089 struct perf_cpu_context *cpuctx,
2090 struct perf_event_context *ctx)
2092 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2094 WARN_ON_ONCE(event->ctx != ctx);
2095 lockdep_assert_held(&ctx->lock);
2097 if (event->state != PERF_EVENT_STATE_ACTIVE)
2101 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2102 * we can schedule events _OUT_ individually through things like
2103 * __perf_remove_from_context().
2105 list_del_init(&event->active_list);
2107 perf_pmu_disable(event->pmu);
2109 event->pmu->del(event, 0);
2112 if (READ_ONCE(event->pending_disable) >= 0) {
2113 WRITE_ONCE(event->pending_disable, -1);
2114 state = PERF_EVENT_STATE_OFF;
2116 perf_event_set_state(event, state);
2118 if (!is_software_event(event))
2119 cpuctx->active_oncpu--;
2120 if (!--ctx->nr_active)
2121 perf_event_ctx_deactivate(ctx);
2122 if (event->attr.freq && event->attr.sample_freq)
2124 if (event->attr.exclusive || !cpuctx->active_oncpu)
2125 cpuctx->exclusive = 0;
2127 perf_pmu_enable(event->pmu);
2131 group_sched_out(struct perf_event *group_event,
2132 struct perf_cpu_context *cpuctx,
2133 struct perf_event_context *ctx)
2135 struct perf_event *event;
2137 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2140 perf_pmu_disable(ctx->pmu);
2142 event_sched_out(group_event, cpuctx, ctx);
2145 * Schedule out siblings (if any):
2147 for_each_sibling_event(event, group_event)
2148 event_sched_out(event, cpuctx, ctx);
2150 perf_pmu_enable(ctx->pmu);
2152 if (group_event->attr.exclusive)
2153 cpuctx->exclusive = 0;
2156 #define DETACH_GROUP 0x01UL
2159 * Cross CPU call to remove a performance event
2161 * We disable the event on the hardware level first. After that we
2162 * remove it from the context list.
2165 __perf_remove_from_context(struct perf_event *event,
2166 struct perf_cpu_context *cpuctx,
2167 struct perf_event_context *ctx,
2170 unsigned long flags = (unsigned long)info;
2172 if (ctx->is_active & EVENT_TIME) {
2173 update_context_time(ctx);
2174 update_cgrp_time_from_cpuctx(cpuctx);
2177 event_sched_out(event, cpuctx, ctx);
2178 if (flags & DETACH_GROUP)
2179 perf_group_detach(event);
2180 list_del_event(event, ctx);
2182 if (!ctx->nr_events && ctx->is_active) {
2185 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2186 cpuctx->task_ctx = NULL;
2192 * Remove the event from a task's (or a CPU's) list of events.
2194 * If event->ctx is a cloned context, callers must make sure that
2195 * every task struct that event->ctx->task could possibly point to
2196 * remains valid. This is OK when called from perf_release since
2197 * that only calls us on the top-level context, which can't be a clone.
2198 * When called from perf_event_exit_task, it's OK because the
2199 * context has been detached from its task.
2201 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2203 struct perf_event_context *ctx = event->ctx;
2205 lockdep_assert_held(&ctx->mutex);
2207 event_function_call(event, __perf_remove_from_context, (void *)flags);
2210 * The above event_function_call() can NO-OP when it hits
2211 * TASK_TOMBSTONE. In that case we must already have been detached
2212 * from the context (by perf_event_exit_event()) but the grouping
2213 * might still be in-tact.
2215 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2216 if ((flags & DETACH_GROUP) &&
2217 (event->attach_state & PERF_ATTACH_GROUP)) {
2219 * Since in that case we cannot possibly be scheduled, simply
2222 raw_spin_lock_irq(&ctx->lock);
2223 perf_group_detach(event);
2224 raw_spin_unlock_irq(&ctx->lock);
2229 * Cross CPU call to disable a performance event
2231 static void __perf_event_disable(struct perf_event *event,
2232 struct perf_cpu_context *cpuctx,
2233 struct perf_event_context *ctx,
2236 if (event->state < PERF_EVENT_STATE_INACTIVE)
2239 if (ctx->is_active & EVENT_TIME) {
2240 update_context_time(ctx);
2241 update_cgrp_time_from_event(event);
2244 if (event == event->group_leader)
2245 group_sched_out(event, cpuctx, ctx);
2247 event_sched_out(event, cpuctx, ctx);
2249 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2255 * If event->ctx is a cloned context, callers must make sure that
2256 * every task struct that event->ctx->task could possibly point to
2257 * remains valid. This condition is satisfied when called through
2258 * perf_event_for_each_child or perf_event_for_each because they
2259 * hold the top-level event's child_mutex, so any descendant that
2260 * goes to exit will block in perf_event_exit_event().
2262 * When called from perf_pending_event it's OK because event->ctx
2263 * is the current context on this CPU and preemption is disabled,
2264 * hence we can't get into perf_event_task_sched_out for this context.
2266 static void _perf_event_disable(struct perf_event *event)
2268 struct perf_event_context *ctx = event->ctx;
2270 raw_spin_lock_irq(&ctx->lock);
2271 if (event->state <= PERF_EVENT_STATE_OFF) {
2272 raw_spin_unlock_irq(&ctx->lock);
2275 raw_spin_unlock_irq(&ctx->lock);
2277 event_function_call(event, __perf_event_disable, NULL);
2280 void perf_event_disable_local(struct perf_event *event)
2282 event_function_local(event, __perf_event_disable, NULL);
2286 * Strictly speaking kernel users cannot create groups and therefore this
2287 * interface does not need the perf_event_ctx_lock() magic.
2289 void perf_event_disable(struct perf_event *event)
2291 struct perf_event_context *ctx;
2293 ctx = perf_event_ctx_lock(event);
2294 _perf_event_disable(event);
2295 perf_event_ctx_unlock(event, ctx);
2297 EXPORT_SYMBOL_GPL(perf_event_disable);
2299 void perf_event_disable_inatomic(struct perf_event *event)
2301 WRITE_ONCE(event->pending_disable, smp_processor_id());
2302 /* can fail, see perf_pending_event_disable() */
2303 irq_work_queue(&event->pending);
2306 static void perf_set_shadow_time(struct perf_event *event,
2307 struct perf_event_context *ctx)
2310 * use the correct time source for the time snapshot
2312 * We could get by without this by leveraging the
2313 * fact that to get to this function, the caller
2314 * has most likely already called update_context_time()
2315 * and update_cgrp_time_xx() and thus both timestamp
2316 * are identical (or very close). Given that tstamp is,
2317 * already adjusted for cgroup, we could say that:
2318 * tstamp - ctx->timestamp
2320 * tstamp - cgrp->timestamp.
2322 * Then, in perf_output_read(), the calculation would
2323 * work with no changes because:
2324 * - event is guaranteed scheduled in
2325 * - no scheduled out in between
2326 * - thus the timestamp would be the same
2328 * But this is a bit hairy.
2330 * So instead, we have an explicit cgroup call to remain
2331 * within the time time source all along. We believe it
2332 * is cleaner and simpler to understand.
2334 if (is_cgroup_event(event))
2335 perf_cgroup_set_shadow_time(event, event->tstamp);
2337 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2340 #define MAX_INTERRUPTS (~0ULL)
2342 static void perf_log_throttle(struct perf_event *event, int enable);
2343 static void perf_log_itrace_start(struct perf_event *event);
2346 event_sched_in(struct perf_event *event,
2347 struct perf_cpu_context *cpuctx,
2348 struct perf_event_context *ctx)
2352 lockdep_assert_held(&ctx->lock);
2354 if (event->state <= PERF_EVENT_STATE_OFF)
2357 WRITE_ONCE(event->oncpu, smp_processor_id());
2359 * Order event::oncpu write to happen before the ACTIVE state is
2360 * visible. This allows perf_event_{stop,read}() to observe the correct
2361 * ->oncpu if it sees ACTIVE.
2364 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2367 * Unthrottle events, since we scheduled we might have missed several
2368 * ticks already, also for a heavily scheduling task there is little
2369 * guarantee it'll get a tick in a timely manner.
2371 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2372 perf_log_throttle(event, 1);
2373 event->hw.interrupts = 0;
2376 perf_pmu_disable(event->pmu);
2378 perf_set_shadow_time(event, ctx);
2380 perf_log_itrace_start(event);
2382 if (event->pmu->add(event, PERF_EF_START)) {
2383 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2389 if (!is_software_event(event))
2390 cpuctx->active_oncpu++;
2391 if (!ctx->nr_active++)
2392 perf_event_ctx_activate(ctx);
2393 if (event->attr.freq && event->attr.sample_freq)
2396 if (event->attr.exclusive)
2397 cpuctx->exclusive = 1;
2400 perf_pmu_enable(event->pmu);
2406 group_sched_in(struct perf_event *group_event,
2407 struct perf_cpu_context *cpuctx,
2408 struct perf_event_context *ctx)
2410 struct perf_event *event, *partial_group = NULL;
2411 struct pmu *pmu = ctx->pmu;
2413 if (group_event->state == PERF_EVENT_STATE_OFF)
2416 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2418 if (event_sched_in(group_event, cpuctx, ctx)) {
2419 pmu->cancel_txn(pmu);
2420 perf_mux_hrtimer_restart(cpuctx);
2425 * Schedule in siblings as one group (if any):
2427 for_each_sibling_event(event, group_event) {
2428 if (event_sched_in(event, cpuctx, ctx)) {
2429 partial_group = event;
2434 if (!pmu->commit_txn(pmu))
2439 * Groups can be scheduled in as one unit only, so undo any
2440 * partial group before returning:
2441 * The events up to the failed event are scheduled out normally.
2443 for_each_sibling_event(event, group_event) {
2444 if (event == partial_group)
2447 event_sched_out(event, cpuctx, ctx);
2449 event_sched_out(group_event, cpuctx, ctx);
2451 pmu->cancel_txn(pmu);
2453 perf_mux_hrtimer_restart(cpuctx);
2459 * Work out whether we can put this event group on the CPU now.
2461 static int group_can_go_on(struct perf_event *event,
2462 struct perf_cpu_context *cpuctx,
2466 * Groups consisting entirely of software events can always go on.
2468 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2471 * If an exclusive group is already on, no other hardware
2474 if (cpuctx->exclusive)
2477 * If this group is exclusive and there are already
2478 * events on the CPU, it can't go on.
2480 if (event->attr.exclusive && cpuctx->active_oncpu)
2483 * Otherwise, try to add it if all previous groups were able
2489 static void add_event_to_ctx(struct perf_event *event,
2490 struct perf_event_context *ctx)
2492 list_add_event(event, ctx);
2493 perf_group_attach(event);
2496 static void ctx_sched_out(struct perf_event_context *ctx,
2497 struct perf_cpu_context *cpuctx,
2498 enum event_type_t event_type);
2500 ctx_sched_in(struct perf_event_context *ctx,
2501 struct perf_cpu_context *cpuctx,
2502 enum event_type_t event_type,
2503 struct task_struct *task);
2505 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2506 struct perf_event_context *ctx,
2507 enum event_type_t event_type)
2509 if (!cpuctx->task_ctx)
2512 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2515 ctx_sched_out(ctx, cpuctx, event_type);
2518 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2519 struct perf_event_context *ctx,
2520 struct task_struct *task)
2522 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2524 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2525 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2527 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2531 * We want to maintain the following priority of scheduling:
2532 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2533 * - task pinned (EVENT_PINNED)
2534 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2535 * - task flexible (EVENT_FLEXIBLE).
2537 * In order to avoid unscheduling and scheduling back in everything every
2538 * time an event is added, only do it for the groups of equal priority and
2541 * This can be called after a batch operation on task events, in which case
2542 * event_type is a bit mask of the types of events involved. For CPU events,
2543 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2545 static void ctx_resched(struct perf_cpu_context *cpuctx,
2546 struct perf_event_context *task_ctx,
2547 enum event_type_t event_type)
2549 enum event_type_t ctx_event_type;
2550 bool cpu_event = !!(event_type & EVENT_CPU);
2553 * If pinned groups are involved, flexible groups also need to be
2556 if (event_type & EVENT_PINNED)
2557 event_type |= EVENT_FLEXIBLE;
2559 ctx_event_type = event_type & EVENT_ALL;
2561 perf_pmu_disable(cpuctx->ctx.pmu);
2563 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2566 * Decide which cpu ctx groups to schedule out based on the types
2567 * of events that caused rescheduling:
2568 * - EVENT_CPU: schedule out corresponding groups;
2569 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2570 * - otherwise, do nothing more.
2573 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2574 else if (ctx_event_type & EVENT_PINNED)
2575 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2577 perf_event_sched_in(cpuctx, task_ctx, current);
2578 perf_pmu_enable(cpuctx->ctx.pmu);
2581 void perf_pmu_resched(struct pmu *pmu)
2583 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2584 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2586 perf_ctx_lock(cpuctx, task_ctx);
2587 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2588 perf_ctx_unlock(cpuctx, task_ctx);
2592 * Cross CPU call to install and enable a performance event
2594 * Very similar to remote_function() + event_function() but cannot assume that
2595 * things like ctx->is_active and cpuctx->task_ctx are set.
2597 static int __perf_install_in_context(void *info)
2599 struct perf_event *event = info;
2600 struct perf_event_context *ctx = event->ctx;
2601 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2602 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2603 bool reprogram = true;
2606 raw_spin_lock(&cpuctx->ctx.lock);
2608 raw_spin_lock(&ctx->lock);
2611 reprogram = (ctx->task == current);
2614 * If the task is running, it must be running on this CPU,
2615 * otherwise we cannot reprogram things.
2617 * If its not running, we don't care, ctx->lock will
2618 * serialize against it becoming runnable.
2620 if (task_curr(ctx->task) && !reprogram) {
2625 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2626 } else if (task_ctx) {
2627 raw_spin_lock(&task_ctx->lock);
2630 #ifdef CONFIG_CGROUP_PERF
2631 if (is_cgroup_event(event)) {
2633 * If the current cgroup doesn't match the event's
2634 * cgroup, we should not try to schedule it.
2636 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2637 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2638 event->cgrp->css.cgroup);
2643 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2644 add_event_to_ctx(event, ctx);
2645 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2647 add_event_to_ctx(event, ctx);
2651 perf_ctx_unlock(cpuctx, task_ctx);
2656 static bool exclusive_event_installable(struct perf_event *event,
2657 struct perf_event_context *ctx);
2660 * Attach a performance event to a context.
2662 * Very similar to event_function_call, see comment there.
2665 perf_install_in_context(struct perf_event_context *ctx,
2666 struct perf_event *event,
2669 struct task_struct *task = READ_ONCE(ctx->task);
2671 lockdep_assert_held(&ctx->mutex);
2673 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2675 if (event->cpu != -1)
2679 * Ensures that if we can observe event->ctx, both the event and ctx
2680 * will be 'complete'. See perf_iterate_sb_cpu().
2682 smp_store_release(&event->ctx, ctx);
2685 * perf_event_attr::disabled events will not run and can be initialized
2686 * without IPI. Except when this is the first event for the context, in
2687 * that case we need the magic of the IPI to set ctx->is_active.
2689 * The IOC_ENABLE that is sure to follow the creation of a disabled
2690 * event will issue the IPI and reprogram the hardware.
2692 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2693 raw_spin_lock_irq(&ctx->lock);
2694 if (ctx->task == TASK_TOMBSTONE) {
2695 raw_spin_unlock_irq(&ctx->lock);
2698 add_event_to_ctx(event, ctx);
2699 raw_spin_unlock_irq(&ctx->lock);
2704 cpu_function_call(cpu, __perf_install_in_context, event);
2709 * Should not happen, we validate the ctx is still alive before calling.
2711 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2715 * Installing events is tricky because we cannot rely on ctx->is_active
2716 * to be set in case this is the nr_events 0 -> 1 transition.
2718 * Instead we use task_curr(), which tells us if the task is running.
2719 * However, since we use task_curr() outside of rq::lock, we can race
2720 * against the actual state. This means the result can be wrong.
2722 * If we get a false positive, we retry, this is harmless.
2724 * If we get a false negative, things are complicated. If we are after
2725 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2726 * value must be correct. If we're before, it doesn't matter since
2727 * perf_event_context_sched_in() will program the counter.
2729 * However, this hinges on the remote context switch having observed
2730 * our task->perf_event_ctxp[] store, such that it will in fact take
2731 * ctx::lock in perf_event_context_sched_in().
2733 * We do this by task_function_call(), if the IPI fails to hit the task
2734 * we know any future context switch of task must see the
2735 * perf_event_ctpx[] store.
2739 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2740 * task_cpu() load, such that if the IPI then does not find the task
2741 * running, a future context switch of that task must observe the
2746 if (!task_function_call(task, __perf_install_in_context, event))
2749 raw_spin_lock_irq(&ctx->lock);
2751 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2753 * Cannot happen because we already checked above (which also
2754 * cannot happen), and we hold ctx->mutex, which serializes us
2755 * against perf_event_exit_task_context().
2757 raw_spin_unlock_irq(&ctx->lock);
2761 * If the task is not running, ctx->lock will avoid it becoming so,
2762 * thus we can safely install the event.
2764 if (task_curr(task)) {
2765 raw_spin_unlock_irq(&ctx->lock);
2768 add_event_to_ctx(event, ctx);
2769 raw_spin_unlock_irq(&ctx->lock);
2773 * Cross CPU call to enable a performance event
2775 static void __perf_event_enable(struct perf_event *event,
2776 struct perf_cpu_context *cpuctx,
2777 struct perf_event_context *ctx,
2780 struct perf_event *leader = event->group_leader;
2781 struct perf_event_context *task_ctx;
2783 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2784 event->state <= PERF_EVENT_STATE_ERROR)
2788 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2790 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2792 if (!ctx->is_active)
2795 if (!event_filter_match(event)) {
2796 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2801 * If the event is in a group and isn't the group leader,
2802 * then don't put it on unless the group is on.
2804 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2805 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2809 task_ctx = cpuctx->task_ctx;
2811 WARN_ON_ONCE(task_ctx != ctx);
2813 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2819 * If event->ctx is a cloned context, callers must make sure that
2820 * every task struct that event->ctx->task could possibly point to
2821 * remains valid. This condition is satisfied when called through
2822 * perf_event_for_each_child or perf_event_for_each as described
2823 * for perf_event_disable.
2825 static void _perf_event_enable(struct perf_event *event)
2827 struct perf_event_context *ctx = event->ctx;
2829 raw_spin_lock_irq(&ctx->lock);
2830 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2831 event->state < PERF_EVENT_STATE_ERROR) {
2832 raw_spin_unlock_irq(&ctx->lock);
2837 * If the event is in error state, clear that first.
2839 * That way, if we see the event in error state below, we know that it
2840 * has gone back into error state, as distinct from the task having
2841 * been scheduled away before the cross-call arrived.
2843 if (event->state == PERF_EVENT_STATE_ERROR)
2844 event->state = PERF_EVENT_STATE_OFF;
2845 raw_spin_unlock_irq(&ctx->lock);
2847 event_function_call(event, __perf_event_enable, NULL);
2851 * See perf_event_disable();
2853 void perf_event_enable(struct perf_event *event)
2855 struct perf_event_context *ctx;
2857 ctx = perf_event_ctx_lock(event);
2858 _perf_event_enable(event);
2859 perf_event_ctx_unlock(event, ctx);
2861 EXPORT_SYMBOL_GPL(perf_event_enable);
2863 struct stop_event_data {
2864 struct perf_event *event;
2865 unsigned int restart;
2868 static int __perf_event_stop(void *info)
2870 struct stop_event_data *sd = info;
2871 struct perf_event *event = sd->event;
2873 /* if it's already INACTIVE, do nothing */
2874 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2877 /* matches smp_wmb() in event_sched_in() */
2881 * There is a window with interrupts enabled before we get here,
2882 * so we need to check again lest we try to stop another CPU's event.
2884 if (READ_ONCE(event->oncpu) != smp_processor_id())
2887 event->pmu->stop(event, PERF_EF_UPDATE);
2890 * May race with the actual stop (through perf_pmu_output_stop()),
2891 * but it is only used for events with AUX ring buffer, and such
2892 * events will refuse to restart because of rb::aux_mmap_count==0,
2893 * see comments in perf_aux_output_begin().
2895 * Since this is happening on an event-local CPU, no trace is lost
2899 event->pmu->start(event, 0);
2904 static int perf_event_stop(struct perf_event *event, int restart)
2906 struct stop_event_data sd = {
2913 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2916 /* matches smp_wmb() in event_sched_in() */
2920 * We only want to restart ACTIVE events, so if the event goes
2921 * inactive here (event->oncpu==-1), there's nothing more to do;
2922 * fall through with ret==-ENXIO.
2924 ret = cpu_function_call(READ_ONCE(event->oncpu),
2925 __perf_event_stop, &sd);
2926 } while (ret == -EAGAIN);
2932 * In order to contain the amount of racy and tricky in the address filter
2933 * configuration management, it is a two part process:
2935 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2936 * we update the addresses of corresponding vmas in
2937 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2938 * (p2) when an event is scheduled in (pmu::add), it calls
2939 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2940 * if the generation has changed since the previous call.
2942 * If (p1) happens while the event is active, we restart it to force (p2).
2944 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2945 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2947 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2948 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2950 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2953 void perf_event_addr_filters_sync(struct perf_event *event)
2955 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2957 if (!has_addr_filter(event))
2960 raw_spin_lock(&ifh->lock);
2961 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2962 event->pmu->addr_filters_sync(event);
2963 event->hw.addr_filters_gen = event->addr_filters_gen;
2965 raw_spin_unlock(&ifh->lock);
2967 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2969 static int _perf_event_refresh(struct perf_event *event, int refresh)
2972 * not supported on inherited events
2974 if (event->attr.inherit || !is_sampling_event(event))
2977 atomic_add(refresh, &event->event_limit);
2978 _perf_event_enable(event);
2984 * See perf_event_disable()
2986 int perf_event_refresh(struct perf_event *event, int refresh)
2988 struct perf_event_context *ctx;
2991 ctx = perf_event_ctx_lock(event);
2992 ret = _perf_event_refresh(event, refresh);
2993 perf_event_ctx_unlock(event, ctx);
2997 EXPORT_SYMBOL_GPL(perf_event_refresh);
2999 static int perf_event_modify_breakpoint(struct perf_event *bp,
3000 struct perf_event_attr *attr)
3004 _perf_event_disable(bp);
3006 err = modify_user_hw_breakpoint_check(bp, attr, true);
3008 if (!bp->attr.disabled)
3009 _perf_event_enable(bp);
3014 static int perf_event_modify_attr(struct perf_event *event,
3015 struct perf_event_attr *attr)
3017 if (event->attr.type != attr->type)
3020 switch (event->attr.type) {
3021 case PERF_TYPE_BREAKPOINT:
3022 return perf_event_modify_breakpoint(event, attr);
3024 /* Place holder for future additions. */
3029 static void ctx_sched_out(struct perf_event_context *ctx,
3030 struct perf_cpu_context *cpuctx,
3031 enum event_type_t event_type)
3033 struct perf_event *event, *tmp;
3034 int is_active = ctx->is_active;
3036 lockdep_assert_held(&ctx->lock);
3038 if (likely(!ctx->nr_events)) {
3040 * See __perf_remove_from_context().
3042 WARN_ON_ONCE(ctx->is_active);
3044 WARN_ON_ONCE(cpuctx->task_ctx);
3048 ctx->is_active &= ~event_type;
3049 if (!(ctx->is_active & EVENT_ALL))
3053 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3054 if (!ctx->is_active)
3055 cpuctx->task_ctx = NULL;
3059 * Always update time if it was set; not only when it changes.
3060 * Otherwise we can 'forget' to update time for any but the last
3061 * context we sched out. For example:
3063 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3064 * ctx_sched_out(.event_type = EVENT_PINNED)
3066 * would only update time for the pinned events.
3068 if (is_active & EVENT_TIME) {
3069 /* update (and stop) ctx time */
3070 update_context_time(ctx);
3071 update_cgrp_time_from_cpuctx(cpuctx);
3074 is_active ^= ctx->is_active; /* changed bits */
3076 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3080 * If we had been multiplexing, no rotations are necessary, now no events
3083 ctx->rotate_necessary = 0;
3085 perf_pmu_disable(ctx->pmu);
3086 if (is_active & EVENT_PINNED) {
3087 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3088 group_sched_out(event, cpuctx, ctx);
3091 if (is_active & EVENT_FLEXIBLE) {
3092 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3093 group_sched_out(event, cpuctx, ctx);
3095 perf_pmu_enable(ctx->pmu);
3099 * Test whether two contexts are equivalent, i.e. whether they have both been
3100 * cloned from the same version of the same context.
3102 * Equivalence is measured using a generation number in the context that is
3103 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3104 * and list_del_event().
3106 static int context_equiv(struct perf_event_context *ctx1,
3107 struct perf_event_context *ctx2)
3109 lockdep_assert_held(&ctx1->lock);
3110 lockdep_assert_held(&ctx2->lock);
3112 /* Pinning disables the swap optimization */
3113 if (ctx1->pin_count || ctx2->pin_count)
3116 /* If ctx1 is the parent of ctx2 */
3117 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3120 /* If ctx2 is the parent of ctx1 */
3121 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3125 * If ctx1 and ctx2 have the same parent; we flatten the parent
3126 * hierarchy, see perf_event_init_context().
3128 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3129 ctx1->parent_gen == ctx2->parent_gen)
3136 static void __perf_event_sync_stat(struct perf_event *event,
3137 struct perf_event *next_event)
3141 if (!event->attr.inherit_stat)
3145 * Update the event value, we cannot use perf_event_read()
3146 * because we're in the middle of a context switch and have IRQs
3147 * disabled, which upsets smp_call_function_single(), however
3148 * we know the event must be on the current CPU, therefore we
3149 * don't need to use it.
3151 if (event->state == PERF_EVENT_STATE_ACTIVE)
3152 event->pmu->read(event);
3154 perf_event_update_time(event);
3157 * In order to keep per-task stats reliable we need to flip the event
3158 * values when we flip the contexts.
3160 value = local64_read(&next_event->count);
3161 value = local64_xchg(&event->count, value);
3162 local64_set(&next_event->count, value);
3164 swap(event->total_time_enabled, next_event->total_time_enabled);
3165 swap(event->total_time_running, next_event->total_time_running);
3168 * Since we swizzled the values, update the user visible data too.
3170 perf_event_update_userpage(event);
3171 perf_event_update_userpage(next_event);
3174 static void perf_event_sync_stat(struct perf_event_context *ctx,
3175 struct perf_event_context *next_ctx)
3177 struct perf_event *event, *next_event;
3182 update_context_time(ctx);
3184 event = list_first_entry(&ctx->event_list,
3185 struct perf_event, event_entry);
3187 next_event = list_first_entry(&next_ctx->event_list,
3188 struct perf_event, event_entry);
3190 while (&event->event_entry != &ctx->event_list &&
3191 &next_event->event_entry != &next_ctx->event_list) {
3193 __perf_event_sync_stat(event, next_event);
3195 event = list_next_entry(event, event_entry);
3196 next_event = list_next_entry(next_event, event_entry);
3200 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3201 struct task_struct *next)
3203 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3204 struct perf_event_context *next_ctx;
3205 struct perf_event_context *parent, *next_parent;
3206 struct perf_cpu_context *cpuctx;
3212 cpuctx = __get_cpu_context(ctx);
3213 if (!cpuctx->task_ctx)
3217 next_ctx = next->perf_event_ctxp[ctxn];
3221 parent = rcu_dereference(ctx->parent_ctx);
3222 next_parent = rcu_dereference(next_ctx->parent_ctx);
3224 /* If neither context have a parent context; they cannot be clones. */
3225 if (!parent && !next_parent)
3228 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3230 * Looks like the two contexts are clones, so we might be
3231 * able to optimize the context switch. We lock both
3232 * contexts and check that they are clones under the
3233 * lock (including re-checking that neither has been
3234 * uncloned in the meantime). It doesn't matter which
3235 * order we take the locks because no other cpu could
3236 * be trying to lock both of these tasks.
3238 raw_spin_lock(&ctx->lock);
3239 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3240 if (context_equiv(ctx, next_ctx)) {
3241 struct pmu *pmu = ctx->pmu;
3243 WRITE_ONCE(ctx->task, next);
3244 WRITE_ONCE(next_ctx->task, task);
3247 * PMU specific parts of task perf context can require
3248 * additional synchronization. As an example of such
3249 * synchronization see implementation details of Intel
3250 * LBR call stack data profiling;
3252 if (pmu->swap_task_ctx)
3253 pmu->swap_task_ctx(ctx, next_ctx);
3255 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3258 * RCU_INIT_POINTER here is safe because we've not
3259 * modified the ctx and the above modification of
3260 * ctx->task and ctx->task_ctx_data are immaterial
3261 * since those values are always verified under
3262 * ctx->lock which we're now holding.
3264 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3265 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3269 perf_event_sync_stat(ctx, next_ctx);
3271 raw_spin_unlock(&next_ctx->lock);
3272 raw_spin_unlock(&ctx->lock);
3278 raw_spin_lock(&ctx->lock);
3279 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3280 raw_spin_unlock(&ctx->lock);
3284 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3286 void perf_sched_cb_dec(struct pmu *pmu)
3288 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3290 this_cpu_dec(perf_sched_cb_usages);
3292 if (!--cpuctx->sched_cb_usage)
3293 list_del(&cpuctx->sched_cb_entry);
3297 void perf_sched_cb_inc(struct pmu *pmu)
3299 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3301 if (!cpuctx->sched_cb_usage++)
3302 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3304 this_cpu_inc(perf_sched_cb_usages);
3308 * This function provides the context switch callback to the lower code
3309 * layer. It is invoked ONLY when the context switch callback is enabled.
3311 * This callback is relevant even to per-cpu events; for example multi event
3312 * PEBS requires this to provide PID/TID information. This requires we flush
3313 * all queued PEBS records before we context switch to a new task.
3315 static void perf_pmu_sched_task(struct task_struct *prev,
3316 struct task_struct *next,
3319 struct perf_cpu_context *cpuctx;
3325 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3326 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3328 if (WARN_ON_ONCE(!pmu->sched_task))
3331 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3332 perf_pmu_disable(pmu);
3334 pmu->sched_task(cpuctx->task_ctx, sched_in);
3336 perf_pmu_enable(pmu);
3337 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3341 static void perf_event_switch(struct task_struct *task,
3342 struct task_struct *next_prev, bool sched_in);
3344 #define for_each_task_context_nr(ctxn) \
3345 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3348 * Called from scheduler to remove the events of the current task,
3349 * with interrupts disabled.
3351 * We stop each event and update the event value in event->count.
3353 * This does not protect us against NMI, but disable()
3354 * sets the disabled bit in the control field of event _before_
3355 * accessing the event control register. If a NMI hits, then it will
3356 * not restart the event.
3358 void __perf_event_task_sched_out(struct task_struct *task,
3359 struct task_struct *next)
3363 if (__this_cpu_read(perf_sched_cb_usages))
3364 perf_pmu_sched_task(task, next, false);
3366 if (atomic_read(&nr_switch_events))
3367 perf_event_switch(task, next, false);
3369 for_each_task_context_nr(ctxn)
3370 perf_event_context_sched_out(task, ctxn, next);
3373 * if cgroup events exist on this CPU, then we need
3374 * to check if we have to switch out PMU state.
3375 * cgroup event are system-wide mode only
3377 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3378 perf_cgroup_sched_out(task, next);
3382 * Called with IRQs disabled
3384 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3385 enum event_type_t event_type)
3387 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3390 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3391 int (*func)(struct perf_event *, void *), void *data)
3393 struct perf_event **evt, *evt1, *evt2;
3396 evt1 = perf_event_groups_first(groups, -1);
3397 evt2 = perf_event_groups_first(groups, cpu);
3399 while (evt1 || evt2) {
3401 if (evt1->group_index < evt2->group_index)
3411 ret = func(*evt, data);
3415 *evt = perf_event_groups_next(*evt);
3421 struct sched_in_data {
3422 struct perf_event_context *ctx;
3423 struct perf_cpu_context *cpuctx;
3427 static int pinned_sched_in(struct perf_event *event, void *data)
3429 struct sched_in_data *sid = data;
3431 if (event->state <= PERF_EVENT_STATE_OFF)
3434 if (!event_filter_match(event))
3437 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3438 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3439 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3443 * If this pinned group hasn't been scheduled,
3444 * put it in error state.
3446 if (event->state == PERF_EVENT_STATE_INACTIVE)
3447 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3452 static int flexible_sched_in(struct perf_event *event, void *data)
3454 struct sched_in_data *sid = data;
3456 if (event->state <= PERF_EVENT_STATE_OFF)
3459 if (!event_filter_match(event))
3462 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3463 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3465 sid->can_add_hw = 0;
3466 sid->ctx->rotate_necessary = 1;
3469 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3476 ctx_pinned_sched_in(struct perf_event_context *ctx,
3477 struct perf_cpu_context *cpuctx)
3479 struct sched_in_data sid = {
3485 visit_groups_merge(&ctx->pinned_groups,
3487 pinned_sched_in, &sid);
3491 ctx_flexible_sched_in(struct perf_event_context *ctx,
3492 struct perf_cpu_context *cpuctx)
3494 struct sched_in_data sid = {
3500 visit_groups_merge(&ctx->flexible_groups,
3502 flexible_sched_in, &sid);
3506 ctx_sched_in(struct perf_event_context *ctx,
3507 struct perf_cpu_context *cpuctx,
3508 enum event_type_t event_type,
3509 struct task_struct *task)
3511 int is_active = ctx->is_active;
3514 lockdep_assert_held(&ctx->lock);
3516 if (likely(!ctx->nr_events))
3519 ctx->is_active |= (event_type | EVENT_TIME);
3522 cpuctx->task_ctx = ctx;
3524 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3527 is_active ^= ctx->is_active; /* changed bits */
3529 if (is_active & EVENT_TIME) {
3530 /* start ctx time */
3532 ctx->timestamp = now;
3533 perf_cgroup_set_timestamp(task, ctx);
3537 * First go through the list and put on any pinned groups
3538 * in order to give them the best chance of going on.
3540 if (is_active & EVENT_PINNED)
3541 ctx_pinned_sched_in(ctx, cpuctx);
3543 /* Then walk through the lower prio flexible groups */
3544 if (is_active & EVENT_FLEXIBLE)
3545 ctx_flexible_sched_in(ctx, cpuctx);
3548 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3549 enum event_type_t event_type,
3550 struct task_struct *task)
3552 struct perf_event_context *ctx = &cpuctx->ctx;
3554 ctx_sched_in(ctx, cpuctx, event_type, task);
3557 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3558 struct task_struct *task)
3560 struct perf_cpu_context *cpuctx;
3562 cpuctx = __get_cpu_context(ctx);
3563 if (cpuctx->task_ctx == ctx)
3566 perf_ctx_lock(cpuctx, ctx);
3568 * We must check ctx->nr_events while holding ctx->lock, such
3569 * that we serialize against perf_install_in_context().
3571 if (!ctx->nr_events)
3574 perf_pmu_disable(ctx->pmu);
3576 * We want to keep the following priority order:
3577 * cpu pinned (that don't need to move), task pinned,
3578 * cpu flexible, task flexible.
3580 * However, if task's ctx is not carrying any pinned
3581 * events, no need to flip the cpuctx's events around.
3583 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3584 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3585 perf_event_sched_in(cpuctx, ctx, task);
3586 perf_pmu_enable(ctx->pmu);
3589 perf_ctx_unlock(cpuctx, ctx);
3593 * Called from scheduler to add the events of the current task
3594 * with interrupts disabled.
3596 * We restore the event value and then enable it.
3598 * This does not protect us against NMI, but enable()
3599 * sets the enabled bit in the control field of event _before_
3600 * accessing the event control register. If a NMI hits, then it will
3601 * keep the event running.
3603 void __perf_event_task_sched_in(struct task_struct *prev,
3604 struct task_struct *task)
3606 struct perf_event_context *ctx;
3610 * If cgroup events exist on this CPU, then we need to check if we have
3611 * to switch in PMU state; cgroup event are system-wide mode only.
3613 * Since cgroup events are CPU events, we must schedule these in before
3614 * we schedule in the task events.
3616 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3617 perf_cgroup_sched_in(prev, task);
3619 for_each_task_context_nr(ctxn) {
3620 ctx = task->perf_event_ctxp[ctxn];
3624 perf_event_context_sched_in(ctx, task);
3627 if (atomic_read(&nr_switch_events))
3628 perf_event_switch(task, prev, true);
3630 if (__this_cpu_read(perf_sched_cb_usages))
3631 perf_pmu_sched_task(prev, task, true);
3634 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3636 u64 frequency = event->attr.sample_freq;
3637 u64 sec = NSEC_PER_SEC;
3638 u64 divisor, dividend;
3640 int count_fls, nsec_fls, frequency_fls, sec_fls;
3642 count_fls = fls64(count);
3643 nsec_fls = fls64(nsec);
3644 frequency_fls = fls64(frequency);
3648 * We got @count in @nsec, with a target of sample_freq HZ
3649 * the target period becomes:
3652 * period = -------------------
3653 * @nsec * sample_freq
3658 * Reduce accuracy by one bit such that @a and @b converge
3659 * to a similar magnitude.
3661 #define REDUCE_FLS(a, b) \
3663 if (a##_fls > b##_fls) { \
3673 * Reduce accuracy until either term fits in a u64, then proceed with
3674 * the other, so that finally we can do a u64/u64 division.
3676 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3677 REDUCE_FLS(nsec, frequency);
3678 REDUCE_FLS(sec, count);
3681 if (count_fls + sec_fls > 64) {
3682 divisor = nsec * frequency;
3684 while (count_fls + sec_fls > 64) {
3685 REDUCE_FLS(count, sec);
3689 dividend = count * sec;
3691 dividend = count * sec;
3693 while (nsec_fls + frequency_fls > 64) {
3694 REDUCE_FLS(nsec, frequency);
3698 divisor = nsec * frequency;
3704 return div64_u64(dividend, divisor);
3707 static DEFINE_PER_CPU(int, perf_throttled_count);
3708 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3710 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3712 struct hw_perf_event *hwc = &event->hw;
3713 s64 period, sample_period;
3716 period = perf_calculate_period(event, nsec, count);
3718 delta = (s64)(period - hwc->sample_period);
3719 delta = (delta + 7) / 8; /* low pass filter */
3721 sample_period = hwc->sample_period + delta;
3726 hwc->sample_period = sample_period;
3728 if (local64_read(&hwc->period_left) > 8*sample_period) {
3730 event->pmu->stop(event, PERF_EF_UPDATE);
3732 local64_set(&hwc->period_left, 0);
3735 event->pmu->start(event, PERF_EF_RELOAD);
3740 * combine freq adjustment with unthrottling to avoid two passes over the
3741 * events. At the same time, make sure, having freq events does not change
3742 * the rate of unthrottling as that would introduce bias.
3744 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3747 struct perf_event *event;
3748 struct hw_perf_event *hwc;
3749 u64 now, period = TICK_NSEC;
3753 * only need to iterate over all events iff:
3754 * - context have events in frequency mode (needs freq adjust)
3755 * - there are events to unthrottle on this cpu
3757 if (!(ctx->nr_freq || needs_unthr))
3760 raw_spin_lock(&ctx->lock);
3761 perf_pmu_disable(ctx->pmu);
3763 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3764 if (event->state != PERF_EVENT_STATE_ACTIVE)
3767 if (!event_filter_match(event))
3770 perf_pmu_disable(event->pmu);
3774 if (hwc->interrupts == MAX_INTERRUPTS) {
3775 hwc->interrupts = 0;
3776 perf_log_throttle(event, 1);
3777 event->pmu->start(event, 0);
3780 if (!event->attr.freq || !event->attr.sample_freq)
3784 * stop the event and update event->count
3786 event->pmu->stop(event, PERF_EF_UPDATE);
3788 now = local64_read(&event->count);
3789 delta = now - hwc->freq_count_stamp;
3790 hwc->freq_count_stamp = now;
3794 * reload only if value has changed
3795 * we have stopped the event so tell that
3796 * to perf_adjust_period() to avoid stopping it
3800 perf_adjust_period(event, period, delta, false);
3802 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3804 perf_pmu_enable(event->pmu);
3807 perf_pmu_enable(ctx->pmu);
3808 raw_spin_unlock(&ctx->lock);
3812 * Move @event to the tail of the @ctx's elegible events.
3814 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3817 * Rotate the first entry last of non-pinned groups. Rotation might be
3818 * disabled by the inheritance code.
3820 if (ctx->rotate_disable)
3823 perf_event_groups_delete(&ctx->flexible_groups, event);
3824 perf_event_groups_insert(&ctx->flexible_groups, event);
3827 /* pick an event from the flexible_groups to rotate */
3828 static inline struct perf_event *
3829 ctx_event_to_rotate(struct perf_event_context *ctx)
3831 struct perf_event *event;
3833 /* pick the first active flexible event */
3834 event = list_first_entry_or_null(&ctx->flexible_active,
3835 struct perf_event, active_list);
3837 /* if no active flexible event, pick the first event */
3839 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3840 typeof(*event), group_node);
3846 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3848 struct perf_event *cpu_event = NULL, *task_event = NULL;
3849 struct perf_event_context *task_ctx = NULL;
3850 int cpu_rotate, task_rotate;
3853 * Since we run this from IRQ context, nobody can install new
3854 * events, thus the event count values are stable.
3857 cpu_rotate = cpuctx->ctx.rotate_necessary;
3858 task_ctx = cpuctx->task_ctx;
3859 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3861 if (!(cpu_rotate || task_rotate))
3864 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3865 perf_pmu_disable(cpuctx->ctx.pmu);
3868 task_event = ctx_event_to_rotate(task_ctx);
3870 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3873 * As per the order given at ctx_resched() first 'pop' task flexible
3874 * and then, if needed CPU flexible.
3876 if (task_event || (task_ctx && cpu_event))
3877 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3879 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3882 rotate_ctx(task_ctx, task_event);
3884 rotate_ctx(&cpuctx->ctx, cpu_event);
3886 perf_event_sched_in(cpuctx, task_ctx, current);
3888 perf_pmu_enable(cpuctx->ctx.pmu);
3889 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3894 void perf_event_task_tick(void)
3896 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3897 struct perf_event_context *ctx, *tmp;
3900 lockdep_assert_irqs_disabled();
3902 __this_cpu_inc(perf_throttled_seq);
3903 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3904 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3906 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3907 perf_adjust_freq_unthr_context(ctx, throttled);
3910 static int event_enable_on_exec(struct perf_event *event,
3911 struct perf_event_context *ctx)
3913 if (!event->attr.enable_on_exec)
3916 event->attr.enable_on_exec = 0;
3917 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3920 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3926 * Enable all of a task's events that have been marked enable-on-exec.
3927 * This expects task == current.
3929 static void perf_event_enable_on_exec(int ctxn)
3931 struct perf_event_context *ctx, *clone_ctx = NULL;
3932 enum event_type_t event_type = 0;
3933 struct perf_cpu_context *cpuctx;
3934 struct perf_event *event;
3935 unsigned long flags;
3938 local_irq_save(flags);
3939 ctx = current->perf_event_ctxp[ctxn];
3940 if (!ctx || !ctx->nr_events)
3943 cpuctx = __get_cpu_context(ctx);
3944 perf_ctx_lock(cpuctx, ctx);
3945 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3946 list_for_each_entry(event, &ctx->event_list, event_entry) {
3947 enabled |= event_enable_on_exec(event, ctx);
3948 event_type |= get_event_type(event);
3952 * Unclone and reschedule this context if we enabled any event.
3955 clone_ctx = unclone_ctx(ctx);
3956 ctx_resched(cpuctx, ctx, event_type);
3958 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3960 perf_ctx_unlock(cpuctx, ctx);
3963 local_irq_restore(flags);
3969 struct perf_read_data {
3970 struct perf_event *event;
3975 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3977 u16 local_pkg, event_pkg;
3979 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3980 int local_cpu = smp_processor_id();
3982 event_pkg = topology_physical_package_id(event_cpu);
3983 local_pkg = topology_physical_package_id(local_cpu);
3985 if (event_pkg == local_pkg)
3993 * Cross CPU call to read the hardware event
3995 static void __perf_event_read(void *info)
3997 struct perf_read_data *data = info;
3998 struct perf_event *sub, *event = data->event;
3999 struct perf_event_context *ctx = event->ctx;
4000 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4001 struct pmu *pmu = event->pmu;
4004 * If this is a task context, we need to check whether it is
4005 * the current task context of this cpu. If not it has been
4006 * scheduled out before the smp call arrived. In that case
4007 * event->count would have been updated to a recent sample
4008 * when the event was scheduled out.
4010 if (ctx->task && cpuctx->task_ctx != ctx)
4013 raw_spin_lock(&ctx->lock);
4014 if (ctx->is_active & EVENT_TIME) {
4015 update_context_time(ctx);
4016 update_cgrp_time_from_event(event);
4019 perf_event_update_time(event);
4021 perf_event_update_sibling_time(event);
4023 if (event->state != PERF_EVENT_STATE_ACTIVE)
4032 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4036 for_each_sibling_event(sub, event) {
4037 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4039 * Use sibling's PMU rather than @event's since
4040 * sibling could be on different (eg: software) PMU.
4042 sub->pmu->read(sub);
4046 data->ret = pmu->commit_txn(pmu);
4049 raw_spin_unlock(&ctx->lock);
4052 static inline u64 perf_event_count(struct perf_event *event)
4054 return local64_read(&event->count) + atomic64_read(&event->child_count);
4058 * NMI-safe method to read a local event, that is an event that
4060 * - either for the current task, or for this CPU
4061 * - does not have inherit set, for inherited task events
4062 * will not be local and we cannot read them atomically
4063 * - must not have a pmu::count method
4065 int perf_event_read_local(struct perf_event *event, u64 *value,
4066 u64 *enabled, u64 *running)
4068 unsigned long flags;
4072 * Disabling interrupts avoids all counter scheduling (context
4073 * switches, timer based rotation and IPIs).
4075 local_irq_save(flags);
4078 * It must not be an event with inherit set, we cannot read
4079 * all child counters from atomic context.
4081 if (event->attr.inherit) {
4086 /* If this is a per-task event, it must be for current */
4087 if ((event->attach_state & PERF_ATTACH_TASK) &&
4088 event->hw.target != current) {
4093 /* If this is a per-CPU event, it must be for this CPU */
4094 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4095 event->cpu != smp_processor_id()) {
4100 /* If this is a pinned event it must be running on this CPU */
4101 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4107 * If the event is currently on this CPU, its either a per-task event,
4108 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4111 if (event->oncpu == smp_processor_id())
4112 event->pmu->read(event);
4114 *value = local64_read(&event->count);
4115 if (enabled || running) {
4116 u64 now = event->shadow_ctx_time + perf_clock();
4117 u64 __enabled, __running;
4119 __perf_update_times(event, now, &__enabled, &__running);
4121 *enabled = __enabled;
4123 *running = __running;
4126 local_irq_restore(flags);
4131 static int perf_event_read(struct perf_event *event, bool group)
4133 enum perf_event_state state = READ_ONCE(event->state);
4134 int event_cpu, ret = 0;
4137 * If event is enabled and currently active on a CPU, update the
4138 * value in the event structure:
4141 if (state == PERF_EVENT_STATE_ACTIVE) {
4142 struct perf_read_data data;
4145 * Orders the ->state and ->oncpu loads such that if we see
4146 * ACTIVE we must also see the right ->oncpu.
4148 * Matches the smp_wmb() from event_sched_in().
4152 event_cpu = READ_ONCE(event->oncpu);
4153 if ((unsigned)event_cpu >= nr_cpu_ids)
4156 data = (struct perf_read_data){
4163 event_cpu = __perf_event_read_cpu(event, event_cpu);
4166 * Purposely ignore the smp_call_function_single() return
4169 * If event_cpu isn't a valid CPU it means the event got
4170 * scheduled out and that will have updated the event count.
4172 * Therefore, either way, we'll have an up-to-date event count
4175 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4179 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4180 struct perf_event_context *ctx = event->ctx;
4181 unsigned long flags;
4183 raw_spin_lock_irqsave(&ctx->lock, flags);
4184 state = event->state;
4185 if (state != PERF_EVENT_STATE_INACTIVE) {
4186 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4191 * May read while context is not active (e.g., thread is
4192 * blocked), in that case we cannot update context time
4194 if (ctx->is_active & EVENT_TIME) {
4195 update_context_time(ctx);
4196 update_cgrp_time_from_event(event);
4199 perf_event_update_time(event);
4201 perf_event_update_sibling_time(event);
4202 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4209 * Initialize the perf_event context in a task_struct:
4211 static void __perf_event_init_context(struct perf_event_context *ctx)
4213 raw_spin_lock_init(&ctx->lock);
4214 mutex_init(&ctx->mutex);
4215 INIT_LIST_HEAD(&ctx->active_ctx_list);
4216 perf_event_groups_init(&ctx->pinned_groups);
4217 perf_event_groups_init(&ctx->flexible_groups);
4218 INIT_LIST_HEAD(&ctx->event_list);
4219 INIT_LIST_HEAD(&ctx->pinned_active);
4220 INIT_LIST_HEAD(&ctx->flexible_active);
4221 refcount_set(&ctx->refcount, 1);
4224 static struct perf_event_context *
4225 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4227 struct perf_event_context *ctx;
4229 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4233 __perf_event_init_context(ctx);
4235 ctx->task = get_task_struct(task);
4241 static struct task_struct *
4242 find_lively_task_by_vpid(pid_t vpid)
4244 struct task_struct *task;
4250 task = find_task_by_vpid(vpid);
4252 get_task_struct(task);
4256 return ERR_PTR(-ESRCH);
4262 * Returns a matching context with refcount and pincount.
4264 static struct perf_event_context *
4265 find_get_context(struct pmu *pmu, struct task_struct *task,
4266 struct perf_event *event)
4268 struct perf_event_context *ctx, *clone_ctx = NULL;
4269 struct perf_cpu_context *cpuctx;
4270 void *task_ctx_data = NULL;
4271 unsigned long flags;
4273 int cpu = event->cpu;
4276 /* Must be root to operate on a CPU event: */
4277 err = perf_allow_cpu(&event->attr);
4279 return ERR_PTR(err);
4281 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4290 ctxn = pmu->task_ctx_nr;
4294 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4295 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4296 if (!task_ctx_data) {
4303 ctx = perf_lock_task_context(task, ctxn, &flags);
4305 clone_ctx = unclone_ctx(ctx);
4308 if (task_ctx_data && !ctx->task_ctx_data) {
4309 ctx->task_ctx_data = task_ctx_data;
4310 task_ctx_data = NULL;
4312 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4317 ctx = alloc_perf_context(pmu, task);
4322 if (task_ctx_data) {
4323 ctx->task_ctx_data = task_ctx_data;
4324 task_ctx_data = NULL;
4328 mutex_lock(&task->perf_event_mutex);
4330 * If it has already passed perf_event_exit_task().
4331 * we must see PF_EXITING, it takes this mutex too.
4333 if (task->flags & PF_EXITING)
4335 else if (task->perf_event_ctxp[ctxn])
4340 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4342 mutex_unlock(&task->perf_event_mutex);
4344 if (unlikely(err)) {
4353 kfree(task_ctx_data);
4357 kfree(task_ctx_data);
4358 return ERR_PTR(err);
4361 static void perf_event_free_filter(struct perf_event *event);
4362 static void perf_event_free_bpf_prog(struct perf_event *event);
4364 static void free_event_rcu(struct rcu_head *head)
4366 struct perf_event *event;
4368 event = container_of(head, struct perf_event, rcu_head);
4370 put_pid_ns(event->ns);
4371 perf_event_free_filter(event);
4375 static void ring_buffer_attach(struct perf_event *event,
4376 struct ring_buffer *rb);
4378 static void detach_sb_event(struct perf_event *event)
4380 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4382 raw_spin_lock(&pel->lock);
4383 list_del_rcu(&event->sb_list);
4384 raw_spin_unlock(&pel->lock);
4387 static bool is_sb_event(struct perf_event *event)
4389 struct perf_event_attr *attr = &event->attr;
4394 if (event->attach_state & PERF_ATTACH_TASK)
4397 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4398 attr->comm || attr->comm_exec ||
4399 attr->task || attr->ksymbol ||
4400 attr->context_switch ||
4406 static void unaccount_pmu_sb_event(struct perf_event *event)
4408 if (is_sb_event(event))
4409 detach_sb_event(event);
4412 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4417 if (is_cgroup_event(event))
4418 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4421 #ifdef CONFIG_NO_HZ_FULL
4422 static DEFINE_SPINLOCK(nr_freq_lock);
4425 static void unaccount_freq_event_nohz(void)
4427 #ifdef CONFIG_NO_HZ_FULL
4428 spin_lock(&nr_freq_lock);
4429 if (atomic_dec_and_test(&nr_freq_events))
4430 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4431 spin_unlock(&nr_freq_lock);
4435 static void unaccount_freq_event(void)
4437 if (tick_nohz_full_enabled())
4438 unaccount_freq_event_nohz();
4440 atomic_dec(&nr_freq_events);
4443 static void unaccount_event(struct perf_event *event)
4450 if (event->attach_state & PERF_ATTACH_TASK)
4452 if (event->attr.mmap || event->attr.mmap_data)
4453 atomic_dec(&nr_mmap_events);
4454 if (event->attr.comm)
4455 atomic_dec(&nr_comm_events);
4456 if (event->attr.namespaces)
4457 atomic_dec(&nr_namespaces_events);
4458 if (event->attr.task)
4459 atomic_dec(&nr_task_events);
4460 if (event->attr.freq)
4461 unaccount_freq_event();
4462 if (event->attr.context_switch) {
4464 atomic_dec(&nr_switch_events);
4466 if (is_cgroup_event(event))
4468 if (has_branch_stack(event))
4470 if (event->attr.ksymbol)
4471 atomic_dec(&nr_ksymbol_events);
4472 if (event->attr.bpf_event)
4473 atomic_dec(&nr_bpf_events);
4476 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4477 schedule_delayed_work(&perf_sched_work, HZ);
4480 unaccount_event_cpu(event, event->cpu);
4482 unaccount_pmu_sb_event(event);
4485 static void perf_sched_delayed(struct work_struct *work)
4487 mutex_lock(&perf_sched_mutex);
4488 if (atomic_dec_and_test(&perf_sched_count))
4489 static_branch_disable(&perf_sched_events);
4490 mutex_unlock(&perf_sched_mutex);
4494 * The following implement mutual exclusion of events on "exclusive" pmus
4495 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4496 * at a time, so we disallow creating events that might conflict, namely:
4498 * 1) cpu-wide events in the presence of per-task events,
4499 * 2) per-task events in the presence of cpu-wide events,
4500 * 3) two matching events on the same context.
4502 * The former two cases are handled in the allocation path (perf_event_alloc(),
4503 * _free_event()), the latter -- before the first perf_install_in_context().
4505 static int exclusive_event_init(struct perf_event *event)
4507 struct pmu *pmu = event->pmu;
4509 if (!is_exclusive_pmu(pmu))
4513 * Prevent co-existence of per-task and cpu-wide events on the
4514 * same exclusive pmu.
4516 * Negative pmu::exclusive_cnt means there are cpu-wide
4517 * events on this "exclusive" pmu, positive means there are
4520 * Since this is called in perf_event_alloc() path, event::ctx
4521 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4522 * to mean "per-task event", because unlike other attach states it
4523 * never gets cleared.
4525 if (event->attach_state & PERF_ATTACH_TASK) {
4526 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4529 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4536 static void exclusive_event_destroy(struct perf_event *event)
4538 struct pmu *pmu = event->pmu;
4540 if (!is_exclusive_pmu(pmu))
4543 /* see comment in exclusive_event_init() */
4544 if (event->attach_state & PERF_ATTACH_TASK)
4545 atomic_dec(&pmu->exclusive_cnt);
4547 atomic_inc(&pmu->exclusive_cnt);
4550 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4552 if ((e1->pmu == e2->pmu) &&
4553 (e1->cpu == e2->cpu ||
4560 static bool exclusive_event_installable(struct perf_event *event,
4561 struct perf_event_context *ctx)
4563 struct perf_event *iter_event;
4564 struct pmu *pmu = event->pmu;
4566 lockdep_assert_held(&ctx->mutex);
4568 if (!is_exclusive_pmu(pmu))
4571 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4572 if (exclusive_event_match(iter_event, event))
4579 static void perf_addr_filters_splice(struct perf_event *event,
4580 struct list_head *head);
4582 static void _free_event(struct perf_event *event)
4584 irq_work_sync(&event->pending);
4586 unaccount_event(event);
4588 security_perf_event_free(event);
4592 * Can happen when we close an event with re-directed output.
4594 * Since we have a 0 refcount, perf_mmap_close() will skip
4595 * over us; possibly making our ring_buffer_put() the last.
4597 mutex_lock(&event->mmap_mutex);
4598 ring_buffer_attach(event, NULL);
4599 mutex_unlock(&event->mmap_mutex);
4602 if (is_cgroup_event(event))
4603 perf_detach_cgroup(event);
4605 if (!event->parent) {
4606 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4607 put_callchain_buffers();
4610 perf_event_free_bpf_prog(event);
4611 perf_addr_filters_splice(event, NULL);
4612 kfree(event->addr_filter_ranges);
4615 event->destroy(event);
4618 * Must be after ->destroy(), due to uprobe_perf_close() using
4621 if (event->hw.target)
4622 put_task_struct(event->hw.target);
4625 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4626 * all task references must be cleaned up.
4629 put_ctx(event->ctx);
4631 exclusive_event_destroy(event);
4632 module_put(event->pmu->module);
4634 call_rcu(&event->rcu_head, free_event_rcu);
4638 * Used to free events which have a known refcount of 1, such as in error paths
4639 * where the event isn't exposed yet and inherited events.
4641 static void free_event(struct perf_event *event)
4643 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4644 "unexpected event refcount: %ld; ptr=%p\n",
4645 atomic_long_read(&event->refcount), event)) {
4646 /* leak to avoid use-after-free */
4654 * Remove user event from the owner task.
4656 static void perf_remove_from_owner(struct perf_event *event)
4658 struct task_struct *owner;
4662 * Matches the smp_store_release() in perf_event_exit_task(). If we
4663 * observe !owner it means the list deletion is complete and we can
4664 * indeed free this event, otherwise we need to serialize on
4665 * owner->perf_event_mutex.
4667 owner = READ_ONCE(event->owner);
4670 * Since delayed_put_task_struct() also drops the last
4671 * task reference we can safely take a new reference
4672 * while holding the rcu_read_lock().
4674 get_task_struct(owner);
4680 * If we're here through perf_event_exit_task() we're already
4681 * holding ctx->mutex which would be an inversion wrt. the
4682 * normal lock order.
4684 * However we can safely take this lock because its the child
4687 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4690 * We have to re-check the event->owner field, if it is cleared
4691 * we raced with perf_event_exit_task(), acquiring the mutex
4692 * ensured they're done, and we can proceed with freeing the
4696 list_del_init(&event->owner_entry);
4697 smp_store_release(&event->owner, NULL);
4699 mutex_unlock(&owner->perf_event_mutex);
4700 put_task_struct(owner);
4704 static void put_event(struct perf_event *event)
4706 if (!atomic_long_dec_and_test(&event->refcount))
4713 * Kill an event dead; while event:refcount will preserve the event
4714 * object, it will not preserve its functionality. Once the last 'user'
4715 * gives up the object, we'll destroy the thing.
4717 int perf_event_release_kernel(struct perf_event *event)
4719 struct perf_event_context *ctx = event->ctx;
4720 struct perf_event *child, *tmp;
4721 LIST_HEAD(free_list);
4724 * If we got here through err_file: fput(event_file); we will not have
4725 * attached to a context yet.
4728 WARN_ON_ONCE(event->attach_state &
4729 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4733 if (!is_kernel_event(event))
4734 perf_remove_from_owner(event);
4736 ctx = perf_event_ctx_lock(event);
4737 WARN_ON_ONCE(ctx->parent_ctx);
4738 perf_remove_from_context(event, DETACH_GROUP);
4740 raw_spin_lock_irq(&ctx->lock);
4742 * Mark this event as STATE_DEAD, there is no external reference to it
4745 * Anybody acquiring event->child_mutex after the below loop _must_
4746 * also see this, most importantly inherit_event() which will avoid
4747 * placing more children on the list.
4749 * Thus this guarantees that we will in fact observe and kill _ALL_
4752 event->state = PERF_EVENT_STATE_DEAD;
4753 raw_spin_unlock_irq(&ctx->lock);
4755 perf_event_ctx_unlock(event, ctx);
4758 mutex_lock(&event->child_mutex);
4759 list_for_each_entry(child, &event->child_list, child_list) {
4762 * Cannot change, child events are not migrated, see the
4763 * comment with perf_event_ctx_lock_nested().
4765 ctx = READ_ONCE(child->ctx);
4767 * Since child_mutex nests inside ctx::mutex, we must jump
4768 * through hoops. We start by grabbing a reference on the ctx.
4770 * Since the event cannot get freed while we hold the
4771 * child_mutex, the context must also exist and have a !0
4777 * Now that we have a ctx ref, we can drop child_mutex, and
4778 * acquire ctx::mutex without fear of it going away. Then we
4779 * can re-acquire child_mutex.
4781 mutex_unlock(&event->child_mutex);
4782 mutex_lock(&ctx->mutex);
4783 mutex_lock(&event->child_mutex);
4786 * Now that we hold ctx::mutex and child_mutex, revalidate our
4787 * state, if child is still the first entry, it didn't get freed
4788 * and we can continue doing so.
4790 tmp = list_first_entry_or_null(&event->child_list,
4791 struct perf_event, child_list);
4793 perf_remove_from_context(child, DETACH_GROUP);
4794 list_move(&child->child_list, &free_list);
4796 * This matches the refcount bump in inherit_event();
4797 * this can't be the last reference.
4802 mutex_unlock(&event->child_mutex);
4803 mutex_unlock(&ctx->mutex);
4807 mutex_unlock(&event->child_mutex);
4809 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4810 void *var = &child->ctx->refcount;
4812 list_del(&child->child_list);
4816 * Wake any perf_event_free_task() waiting for this event to be
4819 smp_mb(); /* pairs with wait_var_event() */
4824 put_event(event); /* Must be the 'last' reference */
4827 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4830 * Called when the last reference to the file is gone.
4832 static int perf_release(struct inode *inode, struct file *file)
4834 perf_event_release_kernel(file->private_data);
4838 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4840 struct perf_event *child;
4846 mutex_lock(&event->child_mutex);
4848 (void)perf_event_read(event, false);
4849 total += perf_event_count(event);
4851 *enabled += event->total_time_enabled +
4852 atomic64_read(&event->child_total_time_enabled);
4853 *running += event->total_time_running +
4854 atomic64_read(&event->child_total_time_running);
4856 list_for_each_entry(child, &event->child_list, child_list) {
4857 (void)perf_event_read(child, false);
4858 total += perf_event_count(child);
4859 *enabled += child->total_time_enabled;
4860 *running += child->total_time_running;
4862 mutex_unlock(&event->child_mutex);
4867 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4869 struct perf_event_context *ctx;
4872 ctx = perf_event_ctx_lock(event);
4873 count = __perf_event_read_value(event, enabled, running);
4874 perf_event_ctx_unlock(event, ctx);
4878 EXPORT_SYMBOL_GPL(perf_event_read_value);
4880 static int __perf_read_group_add(struct perf_event *leader,
4881 u64 read_format, u64 *values)
4883 struct perf_event_context *ctx = leader->ctx;
4884 struct perf_event *sub;
4885 unsigned long flags;
4886 int n = 1; /* skip @nr */
4889 ret = perf_event_read(leader, true);
4893 raw_spin_lock_irqsave(&ctx->lock, flags);
4896 * Since we co-schedule groups, {enabled,running} times of siblings
4897 * will be identical to those of the leader, so we only publish one
4900 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4901 values[n++] += leader->total_time_enabled +
4902 atomic64_read(&leader->child_total_time_enabled);
4905 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4906 values[n++] += leader->total_time_running +
4907 atomic64_read(&leader->child_total_time_running);
4911 * Write {count,id} tuples for every sibling.
4913 values[n++] += perf_event_count(leader);
4914 if (read_format & PERF_FORMAT_ID)
4915 values[n++] = primary_event_id(leader);
4917 for_each_sibling_event(sub, leader) {
4918 values[n++] += perf_event_count(sub);
4919 if (read_format & PERF_FORMAT_ID)
4920 values[n++] = primary_event_id(sub);
4923 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4927 static int perf_read_group(struct perf_event *event,
4928 u64 read_format, char __user *buf)
4930 struct perf_event *leader = event->group_leader, *child;
4931 struct perf_event_context *ctx = leader->ctx;
4935 lockdep_assert_held(&ctx->mutex);
4937 values = kzalloc(event->read_size, GFP_KERNEL);
4941 values[0] = 1 + leader->nr_siblings;
4944 * By locking the child_mutex of the leader we effectively
4945 * lock the child list of all siblings.. XXX explain how.
4947 mutex_lock(&leader->child_mutex);
4949 ret = __perf_read_group_add(leader, read_format, values);
4953 list_for_each_entry(child, &leader->child_list, child_list) {
4954 ret = __perf_read_group_add(child, read_format, values);
4959 mutex_unlock(&leader->child_mutex);
4961 ret = event->read_size;
4962 if (copy_to_user(buf, values, event->read_size))
4967 mutex_unlock(&leader->child_mutex);
4973 static int perf_read_one(struct perf_event *event,
4974 u64 read_format, char __user *buf)
4976 u64 enabled, running;
4980 values[n++] = __perf_event_read_value(event, &enabled, &running);
4981 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4982 values[n++] = enabled;
4983 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4984 values[n++] = running;
4985 if (read_format & PERF_FORMAT_ID)
4986 values[n++] = primary_event_id(event);
4988 if (copy_to_user(buf, values, n * sizeof(u64)))
4991 return n * sizeof(u64);
4994 static bool is_event_hup(struct perf_event *event)
4998 if (event->state > PERF_EVENT_STATE_EXIT)
5001 mutex_lock(&event->child_mutex);
5002 no_children = list_empty(&event->child_list);
5003 mutex_unlock(&event->child_mutex);
5008 * Read the performance event - simple non blocking version for now
5011 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5013 u64 read_format = event->attr.read_format;
5017 * Return end-of-file for a read on an event that is in
5018 * error state (i.e. because it was pinned but it couldn't be
5019 * scheduled on to the CPU at some point).
5021 if (event->state == PERF_EVENT_STATE_ERROR)
5024 if (count < event->read_size)
5027 WARN_ON_ONCE(event->ctx->parent_ctx);
5028 if (read_format & PERF_FORMAT_GROUP)
5029 ret = perf_read_group(event, read_format, buf);
5031 ret = perf_read_one(event, read_format, buf);
5037 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5039 struct perf_event *event = file->private_data;
5040 struct perf_event_context *ctx;
5043 ret = security_perf_event_read(event);
5047 ctx = perf_event_ctx_lock(event);
5048 ret = __perf_read(event, buf, count);
5049 perf_event_ctx_unlock(event, ctx);
5054 static __poll_t perf_poll(struct file *file, poll_table *wait)
5056 struct perf_event *event = file->private_data;
5057 struct ring_buffer *rb;
5058 __poll_t events = EPOLLHUP;
5060 poll_wait(file, &event->waitq, wait);
5062 if (is_event_hup(event))
5066 * Pin the event->rb by taking event->mmap_mutex; otherwise
5067 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5069 mutex_lock(&event->mmap_mutex);
5072 events = atomic_xchg(&rb->poll, 0);
5073 mutex_unlock(&event->mmap_mutex);
5077 static void _perf_event_reset(struct perf_event *event)
5079 (void)perf_event_read(event, false);
5080 local64_set(&event->count, 0);
5081 perf_event_update_userpage(event);
5084 /* Assume it's not an event with inherit set. */
5085 u64 perf_event_pause(struct perf_event *event, bool reset)
5087 struct perf_event_context *ctx;
5090 ctx = perf_event_ctx_lock(event);
5091 WARN_ON_ONCE(event->attr.inherit);
5092 _perf_event_disable(event);
5093 count = local64_read(&event->count);
5095 local64_set(&event->count, 0);
5096 perf_event_ctx_unlock(event, ctx);
5100 EXPORT_SYMBOL_GPL(perf_event_pause);
5103 * Holding the top-level event's child_mutex means that any
5104 * descendant process that has inherited this event will block
5105 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5106 * task existence requirements of perf_event_enable/disable.
5108 static void perf_event_for_each_child(struct perf_event *event,
5109 void (*func)(struct perf_event *))
5111 struct perf_event *child;
5113 WARN_ON_ONCE(event->ctx->parent_ctx);
5115 mutex_lock(&event->child_mutex);
5117 list_for_each_entry(child, &event->child_list, child_list)
5119 mutex_unlock(&event->child_mutex);
5122 static void perf_event_for_each(struct perf_event *event,
5123 void (*func)(struct perf_event *))
5125 struct perf_event_context *ctx = event->ctx;
5126 struct perf_event *sibling;
5128 lockdep_assert_held(&ctx->mutex);
5130 event = event->group_leader;
5132 perf_event_for_each_child(event, func);
5133 for_each_sibling_event(sibling, event)
5134 perf_event_for_each_child(sibling, func);
5137 static void __perf_event_period(struct perf_event *event,
5138 struct perf_cpu_context *cpuctx,
5139 struct perf_event_context *ctx,
5142 u64 value = *((u64 *)info);
5145 if (event->attr.freq) {
5146 event->attr.sample_freq = value;
5148 event->attr.sample_period = value;
5149 event->hw.sample_period = value;
5152 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5154 perf_pmu_disable(ctx->pmu);
5156 * We could be throttled; unthrottle now to avoid the tick
5157 * trying to unthrottle while we already re-started the event.
5159 if (event->hw.interrupts == MAX_INTERRUPTS) {
5160 event->hw.interrupts = 0;
5161 perf_log_throttle(event, 1);
5163 event->pmu->stop(event, PERF_EF_UPDATE);
5166 local64_set(&event->hw.period_left, 0);
5169 event->pmu->start(event, PERF_EF_RELOAD);
5170 perf_pmu_enable(ctx->pmu);
5174 static int perf_event_check_period(struct perf_event *event, u64 value)
5176 return event->pmu->check_period(event, value);
5179 static int _perf_event_period(struct perf_event *event, u64 value)
5181 if (!is_sampling_event(event))
5187 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5190 if (perf_event_check_period(event, value))
5193 if (!event->attr.freq && (value & (1ULL << 63)))
5196 event_function_call(event, __perf_event_period, &value);
5201 int perf_event_period(struct perf_event *event, u64 value)
5203 struct perf_event_context *ctx;
5206 ctx = perf_event_ctx_lock(event);
5207 ret = _perf_event_period(event, value);
5208 perf_event_ctx_unlock(event, ctx);
5212 EXPORT_SYMBOL_GPL(perf_event_period);
5214 static const struct file_operations perf_fops;
5216 static inline int perf_fget_light(int fd, struct fd *p)
5218 struct fd f = fdget(fd);
5222 if (f.file->f_op != &perf_fops) {
5230 static int perf_event_set_output(struct perf_event *event,
5231 struct perf_event *output_event);
5232 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5233 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5234 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5235 struct perf_event_attr *attr);
5237 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5239 void (*func)(struct perf_event *);
5243 case PERF_EVENT_IOC_ENABLE:
5244 func = _perf_event_enable;
5246 case PERF_EVENT_IOC_DISABLE:
5247 func = _perf_event_disable;
5249 case PERF_EVENT_IOC_RESET:
5250 func = _perf_event_reset;
5253 case PERF_EVENT_IOC_REFRESH:
5254 return _perf_event_refresh(event, arg);
5256 case PERF_EVENT_IOC_PERIOD:
5260 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5263 return _perf_event_period(event, value);
5265 case PERF_EVENT_IOC_ID:
5267 u64 id = primary_event_id(event);
5269 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5274 case PERF_EVENT_IOC_SET_OUTPUT:
5278 struct perf_event *output_event;
5280 ret = perf_fget_light(arg, &output);
5283 output_event = output.file->private_data;
5284 ret = perf_event_set_output(event, output_event);
5287 ret = perf_event_set_output(event, NULL);
5292 case PERF_EVENT_IOC_SET_FILTER:
5293 return perf_event_set_filter(event, (void __user *)arg);
5295 case PERF_EVENT_IOC_SET_BPF:
5296 return perf_event_set_bpf_prog(event, arg);
5298 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5299 struct ring_buffer *rb;
5302 rb = rcu_dereference(event->rb);
5303 if (!rb || !rb->nr_pages) {
5307 rb_toggle_paused(rb, !!arg);
5312 case PERF_EVENT_IOC_QUERY_BPF:
5313 return perf_event_query_prog_array(event, (void __user *)arg);
5315 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5316 struct perf_event_attr new_attr;
5317 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5323 return perf_event_modify_attr(event, &new_attr);
5329 if (flags & PERF_IOC_FLAG_GROUP)
5330 perf_event_for_each(event, func);
5332 perf_event_for_each_child(event, func);
5337 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5339 struct perf_event *event = file->private_data;
5340 struct perf_event_context *ctx;
5343 /* Treat ioctl like writes as it is likely a mutating operation. */
5344 ret = security_perf_event_write(event);
5348 ctx = perf_event_ctx_lock(event);
5349 ret = _perf_ioctl(event, cmd, arg);
5350 perf_event_ctx_unlock(event, ctx);
5355 #ifdef CONFIG_COMPAT
5356 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5359 switch (_IOC_NR(cmd)) {
5360 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5361 case _IOC_NR(PERF_EVENT_IOC_ID):
5362 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5363 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5364 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5365 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5366 cmd &= ~IOCSIZE_MASK;
5367 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5371 return perf_ioctl(file, cmd, arg);
5374 # define perf_compat_ioctl NULL
5377 int perf_event_task_enable(void)
5379 struct perf_event_context *ctx;
5380 struct perf_event *event;
5382 mutex_lock(¤t->perf_event_mutex);
5383 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5384 ctx = perf_event_ctx_lock(event);
5385 perf_event_for_each_child(event, _perf_event_enable);
5386 perf_event_ctx_unlock(event, ctx);
5388 mutex_unlock(¤t->perf_event_mutex);
5393 int perf_event_task_disable(void)
5395 struct perf_event_context *ctx;
5396 struct perf_event *event;
5398 mutex_lock(¤t->perf_event_mutex);
5399 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5400 ctx = perf_event_ctx_lock(event);
5401 perf_event_for_each_child(event, _perf_event_disable);
5402 perf_event_ctx_unlock(event, ctx);
5404 mutex_unlock(¤t->perf_event_mutex);
5409 static int perf_event_index(struct perf_event *event)
5411 if (event->hw.state & PERF_HES_STOPPED)
5414 if (event->state != PERF_EVENT_STATE_ACTIVE)
5417 return event->pmu->event_idx(event);
5420 static void calc_timer_values(struct perf_event *event,
5427 *now = perf_clock();
5428 ctx_time = event->shadow_ctx_time + *now;
5429 __perf_update_times(event, ctx_time, enabled, running);
5432 static void perf_event_init_userpage(struct perf_event *event)
5434 struct perf_event_mmap_page *userpg;
5435 struct ring_buffer *rb;
5438 rb = rcu_dereference(event->rb);
5442 userpg = rb->user_page;
5444 /* Allow new userspace to detect that bit 0 is deprecated */
5445 userpg->cap_bit0_is_deprecated = 1;
5446 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5447 userpg->data_offset = PAGE_SIZE;
5448 userpg->data_size = perf_data_size(rb);
5454 void __weak arch_perf_update_userpage(
5455 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5460 * Callers need to ensure there can be no nesting of this function, otherwise
5461 * the seqlock logic goes bad. We can not serialize this because the arch
5462 * code calls this from NMI context.
5464 void perf_event_update_userpage(struct perf_event *event)
5466 struct perf_event_mmap_page *userpg;
5467 struct ring_buffer *rb;
5468 u64 enabled, running, now;
5471 rb = rcu_dereference(event->rb);
5476 * compute total_time_enabled, total_time_running
5477 * based on snapshot values taken when the event
5478 * was last scheduled in.
5480 * we cannot simply called update_context_time()
5481 * because of locking issue as we can be called in
5484 calc_timer_values(event, &now, &enabled, &running);
5486 userpg = rb->user_page;
5488 * Disable preemption to guarantee consistent time stamps are stored to
5494 userpg->index = perf_event_index(event);
5495 userpg->offset = perf_event_count(event);
5497 userpg->offset -= local64_read(&event->hw.prev_count);
5499 userpg->time_enabled = enabled +
5500 atomic64_read(&event->child_total_time_enabled);
5502 userpg->time_running = running +
5503 atomic64_read(&event->child_total_time_running);
5505 arch_perf_update_userpage(event, userpg, now);
5513 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5515 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5517 struct perf_event *event = vmf->vma->vm_file->private_data;
5518 struct ring_buffer *rb;
5519 vm_fault_t ret = VM_FAULT_SIGBUS;
5521 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5522 if (vmf->pgoff == 0)
5528 rb = rcu_dereference(event->rb);
5532 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5535 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5539 get_page(vmf->page);
5540 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5541 vmf->page->index = vmf->pgoff;
5550 static void ring_buffer_attach(struct perf_event *event,
5551 struct ring_buffer *rb)
5553 struct ring_buffer *old_rb = NULL;
5554 unsigned long flags;
5558 * Should be impossible, we set this when removing
5559 * event->rb_entry and wait/clear when adding event->rb_entry.
5561 WARN_ON_ONCE(event->rcu_pending);
5564 spin_lock_irqsave(&old_rb->event_lock, flags);
5565 list_del_rcu(&event->rb_entry);
5566 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5568 event->rcu_batches = get_state_synchronize_rcu();
5569 event->rcu_pending = 1;
5573 if (event->rcu_pending) {
5574 cond_synchronize_rcu(event->rcu_batches);
5575 event->rcu_pending = 0;
5578 spin_lock_irqsave(&rb->event_lock, flags);
5579 list_add_rcu(&event->rb_entry, &rb->event_list);
5580 spin_unlock_irqrestore(&rb->event_lock, flags);
5584 * Avoid racing with perf_mmap_close(AUX): stop the event
5585 * before swizzling the event::rb pointer; if it's getting
5586 * unmapped, its aux_mmap_count will be 0 and it won't
5587 * restart. See the comment in __perf_pmu_output_stop().
5589 * Data will inevitably be lost when set_output is done in
5590 * mid-air, but then again, whoever does it like this is
5591 * not in for the data anyway.
5594 perf_event_stop(event, 0);
5596 rcu_assign_pointer(event->rb, rb);
5599 ring_buffer_put(old_rb);
5601 * Since we detached before setting the new rb, so that we
5602 * could attach the new rb, we could have missed a wakeup.
5605 wake_up_all(&event->waitq);
5609 static void ring_buffer_wakeup(struct perf_event *event)
5611 struct ring_buffer *rb;
5614 rb = rcu_dereference(event->rb);
5616 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5617 wake_up_all(&event->waitq);
5622 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5624 struct ring_buffer *rb;
5627 rb = rcu_dereference(event->rb);
5629 if (!refcount_inc_not_zero(&rb->refcount))
5637 void ring_buffer_put(struct ring_buffer *rb)
5639 if (!refcount_dec_and_test(&rb->refcount))
5642 WARN_ON_ONCE(!list_empty(&rb->event_list));
5644 call_rcu(&rb->rcu_head, rb_free_rcu);
5647 static void perf_mmap_open(struct vm_area_struct *vma)
5649 struct perf_event *event = vma->vm_file->private_data;
5651 atomic_inc(&event->mmap_count);
5652 atomic_inc(&event->rb->mmap_count);
5655 atomic_inc(&event->rb->aux_mmap_count);
5657 if (event->pmu->event_mapped)
5658 event->pmu->event_mapped(event, vma->vm_mm);
5661 static void perf_pmu_output_stop(struct perf_event *event);
5664 * A buffer can be mmap()ed multiple times; either directly through the same
5665 * event, or through other events by use of perf_event_set_output().
5667 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5668 * the buffer here, where we still have a VM context. This means we need
5669 * to detach all events redirecting to us.
5671 static void perf_mmap_close(struct vm_area_struct *vma)
5673 struct perf_event *event = vma->vm_file->private_data;
5675 struct ring_buffer *rb = ring_buffer_get(event);
5676 struct user_struct *mmap_user = rb->mmap_user;
5677 int mmap_locked = rb->mmap_locked;
5678 unsigned long size = perf_data_size(rb);
5680 if (event->pmu->event_unmapped)
5681 event->pmu->event_unmapped(event, vma->vm_mm);
5684 * rb->aux_mmap_count will always drop before rb->mmap_count and
5685 * event->mmap_count, so it is ok to use event->mmap_mutex to
5686 * serialize with perf_mmap here.
5688 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5689 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5691 * Stop all AUX events that are writing to this buffer,
5692 * so that we can free its AUX pages and corresponding PMU
5693 * data. Note that after rb::aux_mmap_count dropped to zero,
5694 * they won't start any more (see perf_aux_output_begin()).
5696 perf_pmu_output_stop(event);
5698 /* now it's safe to free the pages */
5699 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
5700 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5702 /* this has to be the last one */
5704 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5706 mutex_unlock(&event->mmap_mutex);
5709 atomic_dec(&rb->mmap_count);
5711 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5714 ring_buffer_attach(event, NULL);
5715 mutex_unlock(&event->mmap_mutex);
5717 /* If there's still other mmap()s of this buffer, we're done. */
5718 if (atomic_read(&rb->mmap_count))
5722 * No other mmap()s, detach from all other events that might redirect
5723 * into the now unreachable buffer. Somewhat complicated by the
5724 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5728 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5729 if (!atomic_long_inc_not_zero(&event->refcount)) {
5731 * This event is en-route to free_event() which will
5732 * detach it and remove it from the list.
5738 mutex_lock(&event->mmap_mutex);
5740 * Check we didn't race with perf_event_set_output() which can
5741 * swizzle the rb from under us while we were waiting to
5742 * acquire mmap_mutex.
5744 * If we find a different rb; ignore this event, a next
5745 * iteration will no longer find it on the list. We have to
5746 * still restart the iteration to make sure we're not now
5747 * iterating the wrong list.
5749 if (event->rb == rb)
5750 ring_buffer_attach(event, NULL);
5752 mutex_unlock(&event->mmap_mutex);
5756 * Restart the iteration; either we're on the wrong list or
5757 * destroyed its integrity by doing a deletion.
5764 * It could be there's still a few 0-ref events on the list; they'll
5765 * get cleaned up by free_event() -- they'll also still have their
5766 * ref on the rb and will free it whenever they are done with it.
5768 * Aside from that, this buffer is 'fully' detached and unmapped,
5769 * undo the VM accounting.
5772 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5773 &mmap_user->locked_vm);
5774 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5775 free_uid(mmap_user);
5778 ring_buffer_put(rb); /* could be last */
5781 static const struct vm_operations_struct perf_mmap_vmops = {
5782 .open = perf_mmap_open,
5783 .close = perf_mmap_close, /* non mergeable */
5784 .fault = perf_mmap_fault,
5785 .page_mkwrite = perf_mmap_fault,
5788 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5790 struct perf_event *event = file->private_data;
5791 unsigned long user_locked, user_lock_limit;
5792 struct user_struct *user = current_user();
5793 unsigned long locked, lock_limit;
5794 struct ring_buffer *rb = NULL;
5795 unsigned long vma_size;
5796 unsigned long nr_pages;
5797 long user_extra = 0, extra = 0;
5798 int ret = 0, flags = 0;
5801 * Don't allow mmap() of inherited per-task counters. This would
5802 * create a performance issue due to all children writing to the
5805 if (event->cpu == -1 && event->attr.inherit)
5808 if (!(vma->vm_flags & VM_SHARED))
5811 ret = security_perf_event_read(event);
5815 vma_size = vma->vm_end - vma->vm_start;
5817 if (vma->vm_pgoff == 0) {
5818 nr_pages = (vma_size / PAGE_SIZE) - 1;
5821 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5822 * mapped, all subsequent mappings should have the same size
5823 * and offset. Must be above the normal perf buffer.
5825 u64 aux_offset, aux_size;
5830 nr_pages = vma_size / PAGE_SIZE;
5832 mutex_lock(&event->mmap_mutex);
5839 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5840 aux_size = READ_ONCE(rb->user_page->aux_size);
5842 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5845 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5848 /* already mapped with a different offset */
5849 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5852 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5855 /* already mapped with a different size */
5856 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5859 if (!is_power_of_2(nr_pages))
5862 if (!atomic_inc_not_zero(&rb->mmap_count))
5865 if (rb_has_aux(rb)) {
5866 atomic_inc(&rb->aux_mmap_count);
5871 atomic_set(&rb->aux_mmap_count, 1);
5872 user_extra = nr_pages;
5878 * If we have rb pages ensure they're a power-of-two number, so we
5879 * can do bitmasks instead of modulo.
5881 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5884 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5887 WARN_ON_ONCE(event->ctx->parent_ctx);
5889 mutex_lock(&event->mmap_mutex);
5891 if (event->rb->nr_pages != nr_pages) {
5896 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5898 * Raced against perf_mmap_close() through
5899 * perf_event_set_output(). Try again, hope for better
5902 mutex_unlock(&event->mmap_mutex);
5909 user_extra = nr_pages + 1;
5912 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5915 * Increase the limit linearly with more CPUs:
5917 user_lock_limit *= num_online_cpus();
5919 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5921 if (user_locked > user_lock_limit) {
5923 * charge locked_vm until it hits user_lock_limit;
5924 * charge the rest from pinned_vm
5926 extra = user_locked - user_lock_limit;
5927 user_extra -= extra;
5930 lock_limit = rlimit(RLIMIT_MEMLOCK);
5931 lock_limit >>= PAGE_SHIFT;
5932 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5934 if ((locked > lock_limit) && perf_is_paranoid() &&
5935 !capable(CAP_IPC_LOCK)) {
5940 WARN_ON(!rb && event->rb);
5942 if (vma->vm_flags & VM_WRITE)
5943 flags |= RING_BUFFER_WRITABLE;
5946 rb = rb_alloc(nr_pages,
5947 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5955 atomic_set(&rb->mmap_count, 1);
5956 rb->mmap_user = get_current_user();
5957 rb->mmap_locked = extra;
5959 ring_buffer_attach(event, rb);
5961 perf_event_init_userpage(event);
5962 perf_event_update_userpage(event);
5964 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5965 event->attr.aux_watermark, flags);
5967 rb->aux_mmap_locked = extra;
5972 atomic_long_add(user_extra, &user->locked_vm);
5973 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5975 atomic_inc(&event->mmap_count);
5977 atomic_dec(&rb->mmap_count);
5980 mutex_unlock(&event->mmap_mutex);
5983 * Since pinned accounting is per vm we cannot allow fork() to copy our
5986 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5987 vma->vm_ops = &perf_mmap_vmops;
5989 if (event->pmu->event_mapped)
5990 event->pmu->event_mapped(event, vma->vm_mm);
5995 static int perf_fasync(int fd, struct file *filp, int on)
5997 struct inode *inode = file_inode(filp);
5998 struct perf_event *event = filp->private_data;
6002 retval = fasync_helper(fd, filp, on, &event->fasync);
6003 inode_unlock(inode);
6011 static const struct file_operations perf_fops = {
6012 .llseek = no_llseek,
6013 .release = perf_release,
6016 .unlocked_ioctl = perf_ioctl,
6017 .compat_ioctl = perf_compat_ioctl,
6019 .fasync = perf_fasync,
6025 * If there's data, ensure we set the poll() state and publish everything
6026 * to user-space before waking everybody up.
6029 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6031 /* only the parent has fasync state */
6033 event = event->parent;
6034 return &event->fasync;
6037 void perf_event_wakeup(struct perf_event *event)
6039 ring_buffer_wakeup(event);
6041 if (event->pending_kill) {
6042 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6043 event->pending_kill = 0;
6047 static void perf_pending_event_disable(struct perf_event *event)
6049 int cpu = READ_ONCE(event->pending_disable);
6054 if (cpu == smp_processor_id()) {
6055 WRITE_ONCE(event->pending_disable, -1);
6056 perf_event_disable_local(event);
6063 * perf_event_disable_inatomic()
6064 * @pending_disable = CPU-A;
6068 * @pending_disable = -1;
6071 * perf_event_disable_inatomic()
6072 * @pending_disable = CPU-B;
6073 * irq_work_queue(); // FAILS
6076 * perf_pending_event()
6078 * But the event runs on CPU-B and wants disabling there.
6080 irq_work_queue_on(&event->pending, cpu);
6083 static void perf_pending_event(struct irq_work *entry)
6085 struct perf_event *event = container_of(entry, struct perf_event, pending);
6088 rctx = perf_swevent_get_recursion_context();
6090 * If we 'fail' here, that's OK, it means recursion is already disabled
6091 * and we won't recurse 'further'.
6094 perf_pending_event_disable(event);
6096 if (event->pending_wakeup) {
6097 event->pending_wakeup = 0;
6098 perf_event_wakeup(event);
6102 perf_swevent_put_recursion_context(rctx);
6106 * We assume there is only KVM supporting the callbacks.
6107 * Later on, we might change it to a list if there is
6108 * another virtualization implementation supporting the callbacks.
6110 struct perf_guest_info_callbacks *perf_guest_cbs;
6112 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6114 perf_guest_cbs = cbs;
6117 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6119 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6121 perf_guest_cbs = NULL;
6124 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6127 perf_output_sample_regs(struct perf_output_handle *handle,
6128 struct pt_regs *regs, u64 mask)
6131 DECLARE_BITMAP(_mask, 64);
6133 bitmap_from_u64(_mask, mask);
6134 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6137 val = perf_reg_value(regs, bit);
6138 perf_output_put(handle, val);
6142 static void perf_sample_regs_user(struct perf_regs *regs_user,
6143 struct pt_regs *regs,
6144 struct pt_regs *regs_user_copy)
6146 if (user_mode(regs)) {
6147 regs_user->abi = perf_reg_abi(current);
6148 regs_user->regs = regs;
6149 } else if (!(current->flags & PF_KTHREAD)) {
6150 perf_get_regs_user(regs_user, regs, regs_user_copy);
6152 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6153 regs_user->regs = NULL;
6157 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6158 struct pt_regs *regs)
6160 regs_intr->regs = regs;
6161 regs_intr->abi = perf_reg_abi(current);
6166 * Get remaining task size from user stack pointer.
6168 * It'd be better to take stack vma map and limit this more
6169 * precisely, but there's no way to get it safely under interrupt,
6170 * so using TASK_SIZE as limit.
6172 static u64 perf_ustack_task_size(struct pt_regs *regs)
6174 unsigned long addr = perf_user_stack_pointer(regs);
6176 if (!addr || addr >= TASK_SIZE)
6179 return TASK_SIZE - addr;
6183 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6184 struct pt_regs *regs)
6188 /* No regs, no stack pointer, no dump. */
6193 * Check if we fit in with the requested stack size into the:
6195 * If we don't, we limit the size to the TASK_SIZE.
6197 * - remaining sample size
6198 * If we don't, we customize the stack size to
6199 * fit in to the remaining sample size.
6202 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6203 stack_size = min(stack_size, (u16) task_size);
6205 /* Current header size plus static size and dynamic size. */
6206 header_size += 2 * sizeof(u64);
6208 /* Do we fit in with the current stack dump size? */
6209 if ((u16) (header_size + stack_size) < header_size) {
6211 * If we overflow the maximum size for the sample,
6212 * we customize the stack dump size to fit in.
6214 stack_size = USHRT_MAX - header_size - sizeof(u64);
6215 stack_size = round_up(stack_size, sizeof(u64));
6222 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6223 struct pt_regs *regs)
6225 /* Case of a kernel thread, nothing to dump */
6228 perf_output_put(handle, size);
6238 * - the size requested by user or the best one we can fit
6239 * in to the sample max size
6241 * - user stack dump data
6243 * - the actual dumped size
6247 perf_output_put(handle, dump_size);
6250 sp = perf_user_stack_pointer(regs);
6253 rem = __output_copy_user(handle, (void *) sp, dump_size);
6255 dyn_size = dump_size - rem;
6257 perf_output_skip(handle, rem);
6260 perf_output_put(handle, dyn_size);
6264 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6265 struct perf_sample_data *data,
6268 struct perf_event *sampler = event->aux_event;
6269 struct ring_buffer *rb;
6276 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6279 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6282 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6287 * If this is an NMI hit inside sampling code, don't take
6288 * the sample. See also perf_aux_sample_output().
6290 if (READ_ONCE(rb->aux_in_sampling)) {
6293 size = min_t(size_t, size, perf_aux_size(rb));
6294 data->aux_size = ALIGN(size, sizeof(u64));
6296 ring_buffer_put(rb);
6299 return data->aux_size;
6302 long perf_pmu_snapshot_aux(struct ring_buffer *rb,
6303 struct perf_event *event,
6304 struct perf_output_handle *handle,
6307 unsigned long flags;
6311 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6312 * paths. If we start calling them in NMI context, they may race with
6313 * the IRQ ones, that is, for example, re-starting an event that's just
6314 * been stopped, which is why we're using a separate callback that
6315 * doesn't change the event state.
6317 * IRQs need to be disabled to prevent IPIs from racing with us.
6319 local_irq_save(flags);
6321 * Guard against NMI hits inside the critical section;
6322 * see also perf_prepare_sample_aux().
6324 WRITE_ONCE(rb->aux_in_sampling, 1);
6327 ret = event->pmu->snapshot_aux(event, handle, size);
6330 WRITE_ONCE(rb->aux_in_sampling, 0);
6331 local_irq_restore(flags);
6336 static void perf_aux_sample_output(struct perf_event *event,
6337 struct perf_output_handle *handle,
6338 struct perf_sample_data *data)
6340 struct perf_event *sampler = event->aux_event;
6342 struct ring_buffer *rb;
6345 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6348 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6352 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6355 * An error here means that perf_output_copy() failed (returned a
6356 * non-zero surplus that it didn't copy), which in its current
6357 * enlightened implementation is not possible. If that changes, we'd
6360 if (WARN_ON_ONCE(size < 0))
6364 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6365 * perf_prepare_sample_aux(), so should not be more than that.
6367 pad = data->aux_size - size;
6368 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6373 perf_output_copy(handle, &zero, pad);
6377 ring_buffer_put(rb);
6380 static void __perf_event_header__init_id(struct perf_event_header *header,
6381 struct perf_sample_data *data,
6382 struct perf_event *event)
6384 u64 sample_type = event->attr.sample_type;
6386 data->type = sample_type;
6387 header->size += event->id_header_size;
6389 if (sample_type & PERF_SAMPLE_TID) {
6390 /* namespace issues */
6391 data->tid_entry.pid = perf_event_pid(event, current);
6392 data->tid_entry.tid = perf_event_tid(event, current);
6395 if (sample_type & PERF_SAMPLE_TIME)
6396 data->time = perf_event_clock(event);
6398 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6399 data->id = primary_event_id(event);
6401 if (sample_type & PERF_SAMPLE_STREAM_ID)
6402 data->stream_id = event->id;
6404 if (sample_type & PERF_SAMPLE_CPU) {
6405 data->cpu_entry.cpu = raw_smp_processor_id();
6406 data->cpu_entry.reserved = 0;
6410 void perf_event_header__init_id(struct perf_event_header *header,
6411 struct perf_sample_data *data,
6412 struct perf_event *event)
6414 if (event->attr.sample_id_all)
6415 __perf_event_header__init_id(header, data, event);
6418 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6419 struct perf_sample_data *data)
6421 u64 sample_type = data->type;
6423 if (sample_type & PERF_SAMPLE_TID)
6424 perf_output_put(handle, data->tid_entry);
6426 if (sample_type & PERF_SAMPLE_TIME)
6427 perf_output_put(handle, data->time);
6429 if (sample_type & PERF_SAMPLE_ID)
6430 perf_output_put(handle, data->id);
6432 if (sample_type & PERF_SAMPLE_STREAM_ID)
6433 perf_output_put(handle, data->stream_id);
6435 if (sample_type & PERF_SAMPLE_CPU)
6436 perf_output_put(handle, data->cpu_entry);
6438 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6439 perf_output_put(handle, data->id);
6442 void perf_event__output_id_sample(struct perf_event *event,
6443 struct perf_output_handle *handle,
6444 struct perf_sample_data *sample)
6446 if (event->attr.sample_id_all)
6447 __perf_event__output_id_sample(handle, sample);
6450 static void perf_output_read_one(struct perf_output_handle *handle,
6451 struct perf_event *event,
6452 u64 enabled, u64 running)
6454 u64 read_format = event->attr.read_format;
6458 values[n++] = perf_event_count(event);
6459 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6460 values[n++] = enabled +
6461 atomic64_read(&event->child_total_time_enabled);
6463 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6464 values[n++] = running +
6465 atomic64_read(&event->child_total_time_running);
6467 if (read_format & PERF_FORMAT_ID)
6468 values[n++] = primary_event_id(event);
6470 __output_copy(handle, values, n * sizeof(u64));
6473 static void perf_output_read_group(struct perf_output_handle *handle,
6474 struct perf_event *event,
6475 u64 enabled, u64 running)
6477 struct perf_event *leader = event->group_leader, *sub;
6478 u64 read_format = event->attr.read_format;
6482 values[n++] = 1 + leader->nr_siblings;
6484 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6485 values[n++] = enabled;
6487 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6488 values[n++] = running;
6490 if ((leader != event) &&
6491 (leader->state == PERF_EVENT_STATE_ACTIVE))
6492 leader->pmu->read(leader);
6494 values[n++] = perf_event_count(leader);
6495 if (read_format & PERF_FORMAT_ID)
6496 values[n++] = primary_event_id(leader);
6498 __output_copy(handle, values, n * sizeof(u64));
6500 for_each_sibling_event(sub, leader) {
6503 if ((sub != event) &&
6504 (sub->state == PERF_EVENT_STATE_ACTIVE))
6505 sub->pmu->read(sub);
6507 values[n++] = perf_event_count(sub);
6508 if (read_format & PERF_FORMAT_ID)
6509 values[n++] = primary_event_id(sub);
6511 __output_copy(handle, values, n * sizeof(u64));
6515 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6516 PERF_FORMAT_TOTAL_TIME_RUNNING)
6519 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6521 * The problem is that its both hard and excessively expensive to iterate the
6522 * child list, not to mention that its impossible to IPI the children running
6523 * on another CPU, from interrupt/NMI context.
6525 static void perf_output_read(struct perf_output_handle *handle,
6526 struct perf_event *event)
6528 u64 enabled = 0, running = 0, now;
6529 u64 read_format = event->attr.read_format;
6532 * compute total_time_enabled, total_time_running
6533 * based on snapshot values taken when the event
6534 * was last scheduled in.
6536 * we cannot simply called update_context_time()
6537 * because of locking issue as we are called in
6540 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6541 calc_timer_values(event, &now, &enabled, &running);
6543 if (event->attr.read_format & PERF_FORMAT_GROUP)
6544 perf_output_read_group(handle, event, enabled, running);
6546 perf_output_read_one(handle, event, enabled, running);
6549 void perf_output_sample(struct perf_output_handle *handle,
6550 struct perf_event_header *header,
6551 struct perf_sample_data *data,
6552 struct perf_event *event)
6554 u64 sample_type = data->type;
6556 perf_output_put(handle, *header);
6558 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6559 perf_output_put(handle, data->id);
6561 if (sample_type & PERF_SAMPLE_IP)
6562 perf_output_put(handle, data->ip);
6564 if (sample_type & PERF_SAMPLE_TID)
6565 perf_output_put(handle, data->tid_entry);
6567 if (sample_type & PERF_SAMPLE_TIME)
6568 perf_output_put(handle, data->time);
6570 if (sample_type & PERF_SAMPLE_ADDR)
6571 perf_output_put(handle, data->addr);
6573 if (sample_type & PERF_SAMPLE_ID)
6574 perf_output_put(handle, data->id);
6576 if (sample_type & PERF_SAMPLE_STREAM_ID)
6577 perf_output_put(handle, data->stream_id);
6579 if (sample_type & PERF_SAMPLE_CPU)
6580 perf_output_put(handle, data->cpu_entry);
6582 if (sample_type & PERF_SAMPLE_PERIOD)
6583 perf_output_put(handle, data->period);
6585 if (sample_type & PERF_SAMPLE_READ)
6586 perf_output_read(handle, event);
6588 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6591 size += data->callchain->nr;
6592 size *= sizeof(u64);
6593 __output_copy(handle, data->callchain, size);
6596 if (sample_type & PERF_SAMPLE_RAW) {
6597 struct perf_raw_record *raw = data->raw;
6600 struct perf_raw_frag *frag = &raw->frag;
6602 perf_output_put(handle, raw->size);
6605 __output_custom(handle, frag->copy,
6606 frag->data, frag->size);
6608 __output_copy(handle, frag->data,
6611 if (perf_raw_frag_last(frag))
6616 __output_skip(handle, NULL, frag->pad);
6622 .size = sizeof(u32),
6625 perf_output_put(handle, raw);
6629 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6630 if (data->br_stack) {
6633 size = data->br_stack->nr
6634 * sizeof(struct perf_branch_entry);
6636 perf_output_put(handle, data->br_stack->nr);
6637 perf_output_copy(handle, data->br_stack->entries, size);
6640 * we always store at least the value of nr
6643 perf_output_put(handle, nr);
6647 if (sample_type & PERF_SAMPLE_REGS_USER) {
6648 u64 abi = data->regs_user.abi;
6651 * If there are no regs to dump, notice it through
6652 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6654 perf_output_put(handle, abi);
6657 u64 mask = event->attr.sample_regs_user;
6658 perf_output_sample_regs(handle,
6659 data->regs_user.regs,
6664 if (sample_type & PERF_SAMPLE_STACK_USER) {
6665 perf_output_sample_ustack(handle,
6666 data->stack_user_size,
6667 data->regs_user.regs);
6670 if (sample_type & PERF_SAMPLE_WEIGHT)
6671 perf_output_put(handle, data->weight);
6673 if (sample_type & PERF_SAMPLE_DATA_SRC)
6674 perf_output_put(handle, data->data_src.val);
6676 if (sample_type & PERF_SAMPLE_TRANSACTION)
6677 perf_output_put(handle, data->txn);
6679 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6680 u64 abi = data->regs_intr.abi;
6682 * If there are no regs to dump, notice it through
6683 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6685 perf_output_put(handle, abi);
6688 u64 mask = event->attr.sample_regs_intr;
6690 perf_output_sample_regs(handle,
6691 data->regs_intr.regs,
6696 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6697 perf_output_put(handle, data->phys_addr);
6699 if (sample_type & PERF_SAMPLE_AUX) {
6700 perf_output_put(handle, data->aux_size);
6703 perf_aux_sample_output(event, handle, data);
6706 if (!event->attr.watermark) {
6707 int wakeup_events = event->attr.wakeup_events;
6709 if (wakeup_events) {
6710 struct ring_buffer *rb = handle->rb;
6711 int events = local_inc_return(&rb->events);
6713 if (events >= wakeup_events) {
6714 local_sub(wakeup_events, &rb->events);
6715 local_inc(&rb->wakeup);
6721 static u64 perf_virt_to_phys(u64 virt)
6724 struct page *p = NULL;
6729 if (virt >= TASK_SIZE) {
6730 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6731 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6732 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6733 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6736 * Walking the pages tables for user address.
6737 * Interrupts are disabled, so it prevents any tear down
6738 * of the page tables.
6739 * Try IRQ-safe __get_user_pages_fast first.
6740 * If failed, leave phys_addr as 0.
6742 if ((current->mm != NULL) &&
6743 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6744 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6753 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6755 struct perf_callchain_entry *
6756 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6758 bool kernel = !event->attr.exclude_callchain_kernel;
6759 bool user = !event->attr.exclude_callchain_user;
6760 /* Disallow cross-task user callchains. */
6761 bool crosstask = event->ctx->task && event->ctx->task != current;
6762 const u32 max_stack = event->attr.sample_max_stack;
6763 struct perf_callchain_entry *callchain;
6765 if (!kernel && !user)
6766 return &__empty_callchain;
6768 callchain = get_perf_callchain(regs, 0, kernel, user,
6769 max_stack, crosstask, true);
6770 return callchain ?: &__empty_callchain;
6773 void perf_prepare_sample(struct perf_event_header *header,
6774 struct perf_sample_data *data,
6775 struct perf_event *event,
6776 struct pt_regs *regs)
6778 u64 sample_type = event->attr.sample_type;
6780 header->type = PERF_RECORD_SAMPLE;
6781 header->size = sizeof(*header) + event->header_size;
6784 header->misc |= perf_misc_flags(regs);
6786 __perf_event_header__init_id(header, data, event);
6788 if (sample_type & PERF_SAMPLE_IP)
6789 data->ip = perf_instruction_pointer(regs);
6791 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6794 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6795 data->callchain = perf_callchain(event, regs);
6797 size += data->callchain->nr;
6799 header->size += size * sizeof(u64);
6802 if (sample_type & PERF_SAMPLE_RAW) {
6803 struct perf_raw_record *raw = data->raw;
6807 struct perf_raw_frag *frag = &raw->frag;
6812 if (perf_raw_frag_last(frag))
6817 size = round_up(sum + sizeof(u32), sizeof(u64));
6818 raw->size = size - sizeof(u32);
6819 frag->pad = raw->size - sum;
6824 header->size += size;
6827 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6828 int size = sizeof(u64); /* nr */
6829 if (data->br_stack) {
6830 size += data->br_stack->nr
6831 * sizeof(struct perf_branch_entry);
6833 header->size += size;
6836 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6837 perf_sample_regs_user(&data->regs_user, regs,
6838 &data->regs_user_copy);
6840 if (sample_type & PERF_SAMPLE_REGS_USER) {
6841 /* regs dump ABI info */
6842 int size = sizeof(u64);
6844 if (data->regs_user.regs) {
6845 u64 mask = event->attr.sample_regs_user;
6846 size += hweight64(mask) * sizeof(u64);
6849 header->size += size;
6852 if (sample_type & PERF_SAMPLE_STACK_USER) {
6854 * Either we need PERF_SAMPLE_STACK_USER bit to be always
6855 * processed as the last one or have additional check added
6856 * in case new sample type is added, because we could eat
6857 * up the rest of the sample size.
6859 u16 stack_size = event->attr.sample_stack_user;
6860 u16 size = sizeof(u64);
6862 stack_size = perf_sample_ustack_size(stack_size, header->size,
6863 data->regs_user.regs);
6866 * If there is something to dump, add space for the dump
6867 * itself and for the field that tells the dynamic size,
6868 * which is how many have been actually dumped.
6871 size += sizeof(u64) + stack_size;
6873 data->stack_user_size = stack_size;
6874 header->size += size;
6877 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6878 /* regs dump ABI info */
6879 int size = sizeof(u64);
6881 perf_sample_regs_intr(&data->regs_intr, regs);
6883 if (data->regs_intr.regs) {
6884 u64 mask = event->attr.sample_regs_intr;
6886 size += hweight64(mask) * sizeof(u64);
6889 header->size += size;
6892 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6893 data->phys_addr = perf_virt_to_phys(data->addr);
6895 if (sample_type & PERF_SAMPLE_AUX) {
6898 header->size += sizeof(u64); /* size */
6901 * Given the 16bit nature of header::size, an AUX sample can
6902 * easily overflow it, what with all the preceding sample bits.
6903 * Make sure this doesn't happen by using up to U16_MAX bytes
6904 * per sample in total (rounded down to 8 byte boundary).
6906 size = min_t(size_t, U16_MAX - header->size,
6907 event->attr.aux_sample_size);
6908 size = rounddown(size, 8);
6909 size = perf_prepare_sample_aux(event, data, size);
6911 WARN_ON_ONCE(size + header->size > U16_MAX);
6912 header->size += size;
6915 * If you're adding more sample types here, you likely need to do
6916 * something about the overflowing header::size, like repurpose the
6917 * lowest 3 bits of size, which should be always zero at the moment.
6918 * This raises a more important question, do we really need 512k sized
6919 * samples and why, so good argumentation is in order for whatever you
6922 WARN_ON_ONCE(header->size & 7);
6925 static __always_inline int
6926 __perf_event_output(struct perf_event *event,
6927 struct perf_sample_data *data,
6928 struct pt_regs *regs,
6929 int (*output_begin)(struct perf_output_handle *,
6930 struct perf_event *,
6933 struct perf_output_handle handle;
6934 struct perf_event_header header;
6937 /* protect the callchain buffers */
6940 perf_prepare_sample(&header, data, event, regs);
6942 err = output_begin(&handle, event, header.size);
6946 perf_output_sample(&handle, &header, data, event);
6948 perf_output_end(&handle);
6956 perf_event_output_forward(struct perf_event *event,
6957 struct perf_sample_data *data,
6958 struct pt_regs *regs)
6960 __perf_event_output(event, data, regs, perf_output_begin_forward);
6964 perf_event_output_backward(struct perf_event *event,
6965 struct perf_sample_data *data,
6966 struct pt_regs *regs)
6968 __perf_event_output(event, data, regs, perf_output_begin_backward);
6972 perf_event_output(struct perf_event *event,
6973 struct perf_sample_data *data,
6974 struct pt_regs *regs)
6976 return __perf_event_output(event, data, regs, perf_output_begin);
6983 struct perf_read_event {
6984 struct perf_event_header header;
6991 perf_event_read_event(struct perf_event *event,
6992 struct task_struct *task)
6994 struct perf_output_handle handle;
6995 struct perf_sample_data sample;
6996 struct perf_read_event read_event = {
6998 .type = PERF_RECORD_READ,
7000 .size = sizeof(read_event) + event->read_size,
7002 .pid = perf_event_pid(event, task),
7003 .tid = perf_event_tid(event, task),
7007 perf_event_header__init_id(&read_event.header, &sample, event);
7008 ret = perf_output_begin(&handle, event, read_event.header.size);
7012 perf_output_put(&handle, read_event);
7013 perf_output_read(&handle, event);
7014 perf_event__output_id_sample(event, &handle, &sample);
7016 perf_output_end(&handle);
7019 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7022 perf_iterate_ctx(struct perf_event_context *ctx,
7023 perf_iterate_f output,
7024 void *data, bool all)
7026 struct perf_event *event;
7028 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7030 if (event->state < PERF_EVENT_STATE_INACTIVE)
7032 if (!event_filter_match(event))
7036 output(event, data);
7040 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7042 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7043 struct perf_event *event;
7045 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7047 * Skip events that are not fully formed yet; ensure that
7048 * if we observe event->ctx, both event and ctx will be
7049 * complete enough. See perf_install_in_context().
7051 if (!smp_load_acquire(&event->ctx))
7054 if (event->state < PERF_EVENT_STATE_INACTIVE)
7056 if (!event_filter_match(event))
7058 output(event, data);
7063 * Iterate all events that need to receive side-band events.
7065 * For new callers; ensure that account_pmu_sb_event() includes
7066 * your event, otherwise it might not get delivered.
7069 perf_iterate_sb(perf_iterate_f output, void *data,
7070 struct perf_event_context *task_ctx)
7072 struct perf_event_context *ctx;
7079 * If we have task_ctx != NULL we only notify the task context itself.
7080 * The task_ctx is set only for EXIT events before releasing task
7084 perf_iterate_ctx(task_ctx, output, data, false);
7088 perf_iterate_sb_cpu(output, data);
7090 for_each_task_context_nr(ctxn) {
7091 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7093 perf_iterate_ctx(ctx, output, data, false);
7101 * Clear all file-based filters at exec, they'll have to be
7102 * re-instated when/if these objects are mmapped again.
7104 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7106 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7107 struct perf_addr_filter *filter;
7108 unsigned int restart = 0, count = 0;
7109 unsigned long flags;
7111 if (!has_addr_filter(event))
7114 raw_spin_lock_irqsave(&ifh->lock, flags);
7115 list_for_each_entry(filter, &ifh->list, entry) {
7116 if (filter->path.dentry) {
7117 event->addr_filter_ranges[count].start = 0;
7118 event->addr_filter_ranges[count].size = 0;
7126 event->addr_filters_gen++;
7127 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7130 perf_event_stop(event, 1);
7133 void perf_event_exec(void)
7135 struct perf_event_context *ctx;
7139 for_each_task_context_nr(ctxn) {
7140 ctx = current->perf_event_ctxp[ctxn];
7144 perf_event_enable_on_exec(ctxn);
7146 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
7152 struct remote_output {
7153 struct ring_buffer *rb;
7157 static void __perf_event_output_stop(struct perf_event *event, void *data)
7159 struct perf_event *parent = event->parent;
7160 struct remote_output *ro = data;
7161 struct ring_buffer *rb = ro->rb;
7162 struct stop_event_data sd = {
7166 if (!has_aux(event))
7173 * In case of inheritance, it will be the parent that links to the
7174 * ring-buffer, but it will be the child that's actually using it.
7176 * We are using event::rb to determine if the event should be stopped,
7177 * however this may race with ring_buffer_attach() (through set_output),
7178 * which will make us skip the event that actually needs to be stopped.
7179 * So ring_buffer_attach() has to stop an aux event before re-assigning
7182 if (rcu_dereference(parent->rb) == rb)
7183 ro->err = __perf_event_stop(&sd);
7186 static int __perf_pmu_output_stop(void *info)
7188 struct perf_event *event = info;
7189 struct pmu *pmu = event->ctx->pmu;
7190 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7191 struct remote_output ro = {
7196 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7197 if (cpuctx->task_ctx)
7198 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7205 static void perf_pmu_output_stop(struct perf_event *event)
7207 struct perf_event *iter;
7212 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7214 * For per-CPU events, we need to make sure that neither they
7215 * nor their children are running; for cpu==-1 events it's
7216 * sufficient to stop the event itself if it's active, since
7217 * it can't have children.
7221 cpu = READ_ONCE(iter->oncpu);
7226 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7227 if (err == -EAGAIN) {
7236 * task tracking -- fork/exit
7238 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7241 struct perf_task_event {
7242 struct task_struct *task;
7243 struct perf_event_context *task_ctx;
7246 struct perf_event_header header;
7256 static int perf_event_task_match(struct perf_event *event)
7258 return event->attr.comm || event->attr.mmap ||
7259 event->attr.mmap2 || event->attr.mmap_data ||
7263 static void perf_event_task_output(struct perf_event *event,
7266 struct perf_task_event *task_event = data;
7267 struct perf_output_handle handle;
7268 struct perf_sample_data sample;
7269 struct task_struct *task = task_event->task;
7270 int ret, size = task_event->event_id.header.size;
7272 if (!perf_event_task_match(event))
7275 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7277 ret = perf_output_begin(&handle, event,
7278 task_event->event_id.header.size);
7282 task_event->event_id.pid = perf_event_pid(event, task);
7283 task_event->event_id.ppid = perf_event_pid(event, current);
7285 task_event->event_id.tid = perf_event_tid(event, task);
7286 task_event->event_id.ptid = perf_event_tid(event, current);
7288 task_event->event_id.time = perf_event_clock(event);
7290 perf_output_put(&handle, task_event->event_id);
7292 perf_event__output_id_sample(event, &handle, &sample);
7294 perf_output_end(&handle);
7296 task_event->event_id.header.size = size;
7299 static void perf_event_task(struct task_struct *task,
7300 struct perf_event_context *task_ctx,
7303 struct perf_task_event task_event;
7305 if (!atomic_read(&nr_comm_events) &&
7306 !atomic_read(&nr_mmap_events) &&
7307 !atomic_read(&nr_task_events))
7310 task_event = (struct perf_task_event){
7312 .task_ctx = task_ctx,
7315 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7317 .size = sizeof(task_event.event_id),
7327 perf_iterate_sb(perf_event_task_output,
7332 void perf_event_fork(struct task_struct *task)
7334 perf_event_task(task, NULL, 1);
7335 perf_event_namespaces(task);
7342 struct perf_comm_event {
7343 struct task_struct *task;
7348 struct perf_event_header header;
7355 static int perf_event_comm_match(struct perf_event *event)
7357 return event->attr.comm;
7360 static void perf_event_comm_output(struct perf_event *event,
7363 struct perf_comm_event *comm_event = data;
7364 struct perf_output_handle handle;
7365 struct perf_sample_data sample;
7366 int size = comm_event->event_id.header.size;
7369 if (!perf_event_comm_match(event))
7372 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7373 ret = perf_output_begin(&handle, event,
7374 comm_event->event_id.header.size);
7379 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7380 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7382 perf_output_put(&handle, comm_event->event_id);
7383 __output_copy(&handle, comm_event->comm,
7384 comm_event->comm_size);
7386 perf_event__output_id_sample(event, &handle, &sample);
7388 perf_output_end(&handle);
7390 comm_event->event_id.header.size = size;
7393 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7395 char comm[TASK_COMM_LEN];
7398 memset(comm, 0, sizeof(comm));
7399 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7400 size = ALIGN(strlen(comm)+1, sizeof(u64));
7402 comm_event->comm = comm;
7403 comm_event->comm_size = size;
7405 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7407 perf_iterate_sb(perf_event_comm_output,
7412 void perf_event_comm(struct task_struct *task, bool exec)
7414 struct perf_comm_event comm_event;
7416 if (!atomic_read(&nr_comm_events))
7419 comm_event = (struct perf_comm_event){
7425 .type = PERF_RECORD_COMM,
7426 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7434 perf_event_comm_event(&comm_event);
7438 * namespaces tracking
7441 struct perf_namespaces_event {
7442 struct task_struct *task;
7445 struct perf_event_header header;
7450 struct perf_ns_link_info link_info[NR_NAMESPACES];
7454 static int perf_event_namespaces_match(struct perf_event *event)
7456 return event->attr.namespaces;
7459 static void perf_event_namespaces_output(struct perf_event *event,
7462 struct perf_namespaces_event *namespaces_event = data;
7463 struct perf_output_handle handle;
7464 struct perf_sample_data sample;
7465 u16 header_size = namespaces_event->event_id.header.size;
7468 if (!perf_event_namespaces_match(event))
7471 perf_event_header__init_id(&namespaces_event->event_id.header,
7473 ret = perf_output_begin(&handle, event,
7474 namespaces_event->event_id.header.size);
7478 namespaces_event->event_id.pid = perf_event_pid(event,
7479 namespaces_event->task);
7480 namespaces_event->event_id.tid = perf_event_tid(event,
7481 namespaces_event->task);
7483 perf_output_put(&handle, namespaces_event->event_id);
7485 perf_event__output_id_sample(event, &handle, &sample);
7487 perf_output_end(&handle);
7489 namespaces_event->event_id.header.size = header_size;
7492 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7493 struct task_struct *task,
7494 const struct proc_ns_operations *ns_ops)
7496 struct path ns_path;
7497 struct inode *ns_inode;
7500 error = ns_get_path(&ns_path, task, ns_ops);
7502 ns_inode = ns_path.dentry->d_inode;
7503 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7504 ns_link_info->ino = ns_inode->i_ino;
7509 void perf_event_namespaces(struct task_struct *task)
7511 struct perf_namespaces_event namespaces_event;
7512 struct perf_ns_link_info *ns_link_info;
7514 if (!atomic_read(&nr_namespaces_events))
7517 namespaces_event = (struct perf_namespaces_event){
7521 .type = PERF_RECORD_NAMESPACES,
7523 .size = sizeof(namespaces_event.event_id),
7527 .nr_namespaces = NR_NAMESPACES,
7528 /* .link_info[NR_NAMESPACES] */
7532 ns_link_info = namespaces_event.event_id.link_info;
7534 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7535 task, &mntns_operations);
7537 #ifdef CONFIG_USER_NS
7538 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7539 task, &userns_operations);
7541 #ifdef CONFIG_NET_NS
7542 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7543 task, &netns_operations);
7545 #ifdef CONFIG_UTS_NS
7546 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7547 task, &utsns_operations);
7549 #ifdef CONFIG_IPC_NS
7550 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7551 task, &ipcns_operations);
7553 #ifdef CONFIG_PID_NS
7554 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7555 task, &pidns_operations);
7557 #ifdef CONFIG_CGROUPS
7558 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7559 task, &cgroupns_operations);
7562 perf_iterate_sb(perf_event_namespaces_output,
7571 struct perf_mmap_event {
7572 struct vm_area_struct *vma;
7574 const char *file_name;
7582 struct perf_event_header header;
7592 static int perf_event_mmap_match(struct perf_event *event,
7595 struct perf_mmap_event *mmap_event = data;
7596 struct vm_area_struct *vma = mmap_event->vma;
7597 int executable = vma->vm_flags & VM_EXEC;
7599 return (!executable && event->attr.mmap_data) ||
7600 (executable && (event->attr.mmap || event->attr.mmap2));
7603 static void perf_event_mmap_output(struct perf_event *event,
7606 struct perf_mmap_event *mmap_event = data;
7607 struct perf_output_handle handle;
7608 struct perf_sample_data sample;
7609 int size = mmap_event->event_id.header.size;
7610 u32 type = mmap_event->event_id.header.type;
7613 if (!perf_event_mmap_match(event, data))
7616 if (event->attr.mmap2) {
7617 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7618 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7619 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7620 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7621 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7622 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7623 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7626 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7627 ret = perf_output_begin(&handle, event,
7628 mmap_event->event_id.header.size);
7632 mmap_event->event_id.pid = perf_event_pid(event, current);
7633 mmap_event->event_id.tid = perf_event_tid(event, current);
7635 perf_output_put(&handle, mmap_event->event_id);
7637 if (event->attr.mmap2) {
7638 perf_output_put(&handle, mmap_event->maj);
7639 perf_output_put(&handle, mmap_event->min);
7640 perf_output_put(&handle, mmap_event->ino);
7641 perf_output_put(&handle, mmap_event->ino_generation);
7642 perf_output_put(&handle, mmap_event->prot);
7643 perf_output_put(&handle, mmap_event->flags);
7646 __output_copy(&handle, mmap_event->file_name,
7647 mmap_event->file_size);
7649 perf_event__output_id_sample(event, &handle, &sample);
7651 perf_output_end(&handle);
7653 mmap_event->event_id.header.size = size;
7654 mmap_event->event_id.header.type = type;
7657 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7659 struct vm_area_struct *vma = mmap_event->vma;
7660 struct file *file = vma->vm_file;
7661 int maj = 0, min = 0;
7662 u64 ino = 0, gen = 0;
7663 u32 prot = 0, flags = 0;
7669 if (vma->vm_flags & VM_READ)
7671 if (vma->vm_flags & VM_WRITE)
7673 if (vma->vm_flags & VM_EXEC)
7676 if (vma->vm_flags & VM_MAYSHARE)
7679 flags = MAP_PRIVATE;
7681 if (vma->vm_flags & VM_DENYWRITE)
7682 flags |= MAP_DENYWRITE;
7683 if (vma->vm_flags & VM_MAYEXEC)
7684 flags |= MAP_EXECUTABLE;
7685 if (vma->vm_flags & VM_LOCKED)
7686 flags |= MAP_LOCKED;
7687 if (vma->vm_flags & VM_HUGETLB)
7688 flags |= MAP_HUGETLB;
7691 struct inode *inode;
7694 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7700 * d_path() works from the end of the rb backwards, so we
7701 * need to add enough zero bytes after the string to handle
7702 * the 64bit alignment we do later.
7704 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7709 inode = file_inode(vma->vm_file);
7710 dev = inode->i_sb->s_dev;
7712 gen = inode->i_generation;
7718 if (vma->vm_ops && vma->vm_ops->name) {
7719 name = (char *) vma->vm_ops->name(vma);
7724 name = (char *)arch_vma_name(vma);
7728 if (vma->vm_start <= vma->vm_mm->start_brk &&
7729 vma->vm_end >= vma->vm_mm->brk) {
7733 if (vma->vm_start <= vma->vm_mm->start_stack &&
7734 vma->vm_end >= vma->vm_mm->start_stack) {
7744 strlcpy(tmp, name, sizeof(tmp));
7748 * Since our buffer works in 8 byte units we need to align our string
7749 * size to a multiple of 8. However, we must guarantee the tail end is
7750 * zero'd out to avoid leaking random bits to userspace.
7752 size = strlen(name)+1;
7753 while (!IS_ALIGNED(size, sizeof(u64)))
7754 name[size++] = '\0';
7756 mmap_event->file_name = name;
7757 mmap_event->file_size = size;
7758 mmap_event->maj = maj;
7759 mmap_event->min = min;
7760 mmap_event->ino = ino;
7761 mmap_event->ino_generation = gen;
7762 mmap_event->prot = prot;
7763 mmap_event->flags = flags;
7765 if (!(vma->vm_flags & VM_EXEC))
7766 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7768 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7770 perf_iterate_sb(perf_event_mmap_output,
7778 * Check whether inode and address range match filter criteria.
7780 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7781 struct file *file, unsigned long offset,
7784 /* d_inode(NULL) won't be equal to any mapped user-space file */
7785 if (!filter->path.dentry)
7788 if (d_inode(filter->path.dentry) != file_inode(file))
7791 if (filter->offset > offset + size)
7794 if (filter->offset + filter->size < offset)
7800 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7801 struct vm_area_struct *vma,
7802 struct perf_addr_filter_range *fr)
7804 unsigned long vma_size = vma->vm_end - vma->vm_start;
7805 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7806 struct file *file = vma->vm_file;
7808 if (!perf_addr_filter_match(filter, file, off, vma_size))
7811 if (filter->offset < off) {
7812 fr->start = vma->vm_start;
7813 fr->size = min(vma_size, filter->size - (off - filter->offset));
7815 fr->start = vma->vm_start + filter->offset - off;
7816 fr->size = min(vma->vm_end - fr->start, filter->size);
7822 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7824 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7825 struct vm_area_struct *vma = data;
7826 struct perf_addr_filter *filter;
7827 unsigned int restart = 0, count = 0;
7828 unsigned long flags;
7830 if (!has_addr_filter(event))
7836 raw_spin_lock_irqsave(&ifh->lock, flags);
7837 list_for_each_entry(filter, &ifh->list, entry) {
7838 if (perf_addr_filter_vma_adjust(filter, vma,
7839 &event->addr_filter_ranges[count]))
7846 event->addr_filters_gen++;
7847 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7850 perf_event_stop(event, 1);
7854 * Adjust all task's events' filters to the new vma
7856 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7858 struct perf_event_context *ctx;
7862 * Data tracing isn't supported yet and as such there is no need
7863 * to keep track of anything that isn't related to executable code:
7865 if (!(vma->vm_flags & VM_EXEC))
7869 for_each_task_context_nr(ctxn) {
7870 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7874 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7879 void perf_event_mmap(struct vm_area_struct *vma)
7881 struct perf_mmap_event mmap_event;
7883 if (!atomic_read(&nr_mmap_events))
7886 mmap_event = (struct perf_mmap_event){
7892 .type = PERF_RECORD_MMAP,
7893 .misc = PERF_RECORD_MISC_USER,
7898 .start = vma->vm_start,
7899 .len = vma->vm_end - vma->vm_start,
7900 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7902 /* .maj (attr_mmap2 only) */
7903 /* .min (attr_mmap2 only) */
7904 /* .ino (attr_mmap2 only) */
7905 /* .ino_generation (attr_mmap2 only) */
7906 /* .prot (attr_mmap2 only) */
7907 /* .flags (attr_mmap2 only) */
7910 perf_addr_filters_adjust(vma);
7911 perf_event_mmap_event(&mmap_event);
7914 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7915 unsigned long size, u64 flags)
7917 struct perf_output_handle handle;
7918 struct perf_sample_data sample;
7919 struct perf_aux_event {
7920 struct perf_event_header header;
7926 .type = PERF_RECORD_AUX,
7928 .size = sizeof(rec),
7936 perf_event_header__init_id(&rec.header, &sample, event);
7937 ret = perf_output_begin(&handle, event, rec.header.size);
7942 perf_output_put(&handle, rec);
7943 perf_event__output_id_sample(event, &handle, &sample);
7945 perf_output_end(&handle);
7949 * Lost/dropped samples logging
7951 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7953 struct perf_output_handle handle;
7954 struct perf_sample_data sample;
7958 struct perf_event_header header;
7960 } lost_samples_event = {
7962 .type = PERF_RECORD_LOST_SAMPLES,
7964 .size = sizeof(lost_samples_event),
7969 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7971 ret = perf_output_begin(&handle, event,
7972 lost_samples_event.header.size);
7976 perf_output_put(&handle, lost_samples_event);
7977 perf_event__output_id_sample(event, &handle, &sample);
7978 perf_output_end(&handle);
7982 * context_switch tracking
7985 struct perf_switch_event {
7986 struct task_struct *task;
7987 struct task_struct *next_prev;
7990 struct perf_event_header header;
7996 static int perf_event_switch_match(struct perf_event *event)
7998 return event->attr.context_switch;
8001 static void perf_event_switch_output(struct perf_event *event, void *data)
8003 struct perf_switch_event *se = data;
8004 struct perf_output_handle handle;
8005 struct perf_sample_data sample;
8008 if (!perf_event_switch_match(event))
8011 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8012 if (event->ctx->task) {
8013 se->event_id.header.type = PERF_RECORD_SWITCH;
8014 se->event_id.header.size = sizeof(se->event_id.header);
8016 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8017 se->event_id.header.size = sizeof(se->event_id);
8018 se->event_id.next_prev_pid =
8019 perf_event_pid(event, se->next_prev);
8020 se->event_id.next_prev_tid =
8021 perf_event_tid(event, se->next_prev);
8024 perf_event_header__init_id(&se->event_id.header, &sample, event);
8026 ret = perf_output_begin(&handle, event, se->event_id.header.size);
8030 if (event->ctx->task)
8031 perf_output_put(&handle, se->event_id.header);
8033 perf_output_put(&handle, se->event_id);
8035 perf_event__output_id_sample(event, &handle, &sample);
8037 perf_output_end(&handle);
8040 static void perf_event_switch(struct task_struct *task,
8041 struct task_struct *next_prev, bool sched_in)
8043 struct perf_switch_event switch_event;
8045 /* N.B. caller checks nr_switch_events != 0 */
8047 switch_event = (struct perf_switch_event){
8049 .next_prev = next_prev,
8053 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8056 /* .next_prev_pid */
8057 /* .next_prev_tid */
8061 if (!sched_in && task->state == TASK_RUNNING)
8062 switch_event.event_id.header.misc |=
8063 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8065 perf_iterate_sb(perf_event_switch_output,
8071 * IRQ throttle logging
8074 static void perf_log_throttle(struct perf_event *event, int enable)
8076 struct perf_output_handle handle;
8077 struct perf_sample_data sample;
8081 struct perf_event_header header;
8085 } throttle_event = {
8087 .type = PERF_RECORD_THROTTLE,
8089 .size = sizeof(throttle_event),
8091 .time = perf_event_clock(event),
8092 .id = primary_event_id(event),
8093 .stream_id = event->id,
8097 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8099 perf_event_header__init_id(&throttle_event.header, &sample, event);
8101 ret = perf_output_begin(&handle, event,
8102 throttle_event.header.size);
8106 perf_output_put(&handle, throttle_event);
8107 perf_event__output_id_sample(event, &handle, &sample);
8108 perf_output_end(&handle);
8112 * ksymbol register/unregister tracking
8115 struct perf_ksymbol_event {
8119 struct perf_event_header header;
8127 static int perf_event_ksymbol_match(struct perf_event *event)
8129 return event->attr.ksymbol;
8132 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8134 struct perf_ksymbol_event *ksymbol_event = data;
8135 struct perf_output_handle handle;
8136 struct perf_sample_data sample;
8139 if (!perf_event_ksymbol_match(event))
8142 perf_event_header__init_id(&ksymbol_event->event_id.header,
8144 ret = perf_output_begin(&handle, event,
8145 ksymbol_event->event_id.header.size);
8149 perf_output_put(&handle, ksymbol_event->event_id);
8150 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8151 perf_event__output_id_sample(event, &handle, &sample);
8153 perf_output_end(&handle);
8156 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8159 struct perf_ksymbol_event ksymbol_event;
8160 char name[KSYM_NAME_LEN];
8164 if (!atomic_read(&nr_ksymbol_events))
8167 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8168 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8171 strlcpy(name, sym, KSYM_NAME_LEN);
8172 name_len = strlen(name) + 1;
8173 while (!IS_ALIGNED(name_len, sizeof(u64)))
8174 name[name_len++] = '\0';
8175 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8178 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8180 ksymbol_event = (struct perf_ksymbol_event){
8182 .name_len = name_len,
8185 .type = PERF_RECORD_KSYMBOL,
8186 .size = sizeof(ksymbol_event.event_id) +
8191 .ksym_type = ksym_type,
8196 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8199 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8203 * bpf program load/unload tracking
8206 struct perf_bpf_event {
8207 struct bpf_prog *prog;
8209 struct perf_event_header header;
8213 u8 tag[BPF_TAG_SIZE];
8217 static int perf_event_bpf_match(struct perf_event *event)
8219 return event->attr.bpf_event;
8222 static void perf_event_bpf_output(struct perf_event *event, void *data)
8224 struct perf_bpf_event *bpf_event = data;
8225 struct perf_output_handle handle;
8226 struct perf_sample_data sample;
8229 if (!perf_event_bpf_match(event))
8232 perf_event_header__init_id(&bpf_event->event_id.header,
8234 ret = perf_output_begin(&handle, event,
8235 bpf_event->event_id.header.size);
8239 perf_output_put(&handle, bpf_event->event_id);
8240 perf_event__output_id_sample(event, &handle, &sample);
8242 perf_output_end(&handle);
8245 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8246 enum perf_bpf_event_type type)
8248 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8249 char sym[KSYM_NAME_LEN];
8252 if (prog->aux->func_cnt == 0) {
8253 bpf_get_prog_name(prog, sym);
8254 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8255 (u64)(unsigned long)prog->bpf_func,
8256 prog->jited_len, unregister, sym);
8258 for (i = 0; i < prog->aux->func_cnt; i++) {
8259 struct bpf_prog *subprog = prog->aux->func[i];
8261 bpf_get_prog_name(subprog, sym);
8263 PERF_RECORD_KSYMBOL_TYPE_BPF,
8264 (u64)(unsigned long)subprog->bpf_func,
8265 subprog->jited_len, unregister, sym);
8270 void perf_event_bpf_event(struct bpf_prog *prog,
8271 enum perf_bpf_event_type type,
8274 struct perf_bpf_event bpf_event;
8276 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8277 type >= PERF_BPF_EVENT_MAX)
8281 case PERF_BPF_EVENT_PROG_LOAD:
8282 case PERF_BPF_EVENT_PROG_UNLOAD:
8283 if (atomic_read(&nr_ksymbol_events))
8284 perf_event_bpf_emit_ksymbols(prog, type);
8290 if (!atomic_read(&nr_bpf_events))
8293 bpf_event = (struct perf_bpf_event){
8297 .type = PERF_RECORD_BPF_EVENT,
8298 .size = sizeof(bpf_event.event_id),
8302 .id = prog->aux->id,
8306 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8308 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8309 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8312 void perf_event_itrace_started(struct perf_event *event)
8314 event->attach_state |= PERF_ATTACH_ITRACE;
8317 static void perf_log_itrace_start(struct perf_event *event)
8319 struct perf_output_handle handle;
8320 struct perf_sample_data sample;
8321 struct perf_aux_event {
8322 struct perf_event_header header;
8329 event = event->parent;
8331 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8332 event->attach_state & PERF_ATTACH_ITRACE)
8335 rec.header.type = PERF_RECORD_ITRACE_START;
8336 rec.header.misc = 0;
8337 rec.header.size = sizeof(rec);
8338 rec.pid = perf_event_pid(event, current);
8339 rec.tid = perf_event_tid(event, current);
8341 perf_event_header__init_id(&rec.header, &sample, event);
8342 ret = perf_output_begin(&handle, event, rec.header.size);
8347 perf_output_put(&handle, rec);
8348 perf_event__output_id_sample(event, &handle, &sample);
8350 perf_output_end(&handle);
8354 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8356 struct hw_perf_event *hwc = &event->hw;
8360 seq = __this_cpu_read(perf_throttled_seq);
8361 if (seq != hwc->interrupts_seq) {
8362 hwc->interrupts_seq = seq;
8363 hwc->interrupts = 1;
8366 if (unlikely(throttle
8367 && hwc->interrupts >= max_samples_per_tick)) {
8368 __this_cpu_inc(perf_throttled_count);
8369 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8370 hwc->interrupts = MAX_INTERRUPTS;
8371 perf_log_throttle(event, 0);
8376 if (event->attr.freq) {
8377 u64 now = perf_clock();
8378 s64 delta = now - hwc->freq_time_stamp;
8380 hwc->freq_time_stamp = now;
8382 if (delta > 0 && delta < 2*TICK_NSEC)
8383 perf_adjust_period(event, delta, hwc->last_period, true);
8389 int perf_event_account_interrupt(struct perf_event *event)
8391 return __perf_event_account_interrupt(event, 1);
8395 * Generic event overflow handling, sampling.
8398 static int __perf_event_overflow(struct perf_event *event,
8399 int throttle, struct perf_sample_data *data,
8400 struct pt_regs *regs)
8402 int events = atomic_read(&event->event_limit);
8406 * Non-sampling counters might still use the PMI to fold short
8407 * hardware counters, ignore those.
8409 if (unlikely(!is_sampling_event(event)))
8412 ret = __perf_event_account_interrupt(event, throttle);
8415 * XXX event_limit might not quite work as expected on inherited
8419 event->pending_kill = POLL_IN;
8420 if (events && atomic_dec_and_test(&event->event_limit)) {
8422 event->pending_kill = POLL_HUP;
8424 perf_event_disable_inatomic(event);
8427 READ_ONCE(event->overflow_handler)(event, data, regs);
8429 if (*perf_event_fasync(event) && event->pending_kill) {
8430 event->pending_wakeup = 1;
8431 irq_work_queue(&event->pending);
8437 int perf_event_overflow(struct perf_event *event,
8438 struct perf_sample_data *data,
8439 struct pt_regs *regs)
8441 return __perf_event_overflow(event, 1, data, regs);
8445 * Generic software event infrastructure
8448 struct swevent_htable {
8449 struct swevent_hlist *swevent_hlist;
8450 struct mutex hlist_mutex;
8453 /* Recursion avoidance in each contexts */
8454 int recursion[PERF_NR_CONTEXTS];
8457 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8460 * We directly increment event->count and keep a second value in
8461 * event->hw.period_left to count intervals. This period event
8462 * is kept in the range [-sample_period, 0] so that we can use the
8466 u64 perf_swevent_set_period(struct perf_event *event)
8468 struct hw_perf_event *hwc = &event->hw;
8469 u64 period = hwc->last_period;
8473 hwc->last_period = hwc->sample_period;
8476 old = val = local64_read(&hwc->period_left);
8480 nr = div64_u64(period + val, period);
8481 offset = nr * period;
8483 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8489 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8490 struct perf_sample_data *data,
8491 struct pt_regs *regs)
8493 struct hw_perf_event *hwc = &event->hw;
8497 overflow = perf_swevent_set_period(event);
8499 if (hwc->interrupts == MAX_INTERRUPTS)
8502 for (; overflow; overflow--) {
8503 if (__perf_event_overflow(event, throttle,
8506 * We inhibit the overflow from happening when
8507 * hwc->interrupts == MAX_INTERRUPTS.
8515 static void perf_swevent_event(struct perf_event *event, u64 nr,
8516 struct perf_sample_data *data,
8517 struct pt_regs *regs)
8519 struct hw_perf_event *hwc = &event->hw;
8521 local64_add(nr, &event->count);
8526 if (!is_sampling_event(event))
8529 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8531 return perf_swevent_overflow(event, 1, data, regs);
8533 data->period = event->hw.last_period;
8535 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8536 return perf_swevent_overflow(event, 1, data, regs);
8538 if (local64_add_negative(nr, &hwc->period_left))
8541 perf_swevent_overflow(event, 0, data, regs);
8544 static int perf_exclude_event(struct perf_event *event,
8545 struct pt_regs *regs)
8547 if (event->hw.state & PERF_HES_STOPPED)
8551 if (event->attr.exclude_user && user_mode(regs))
8554 if (event->attr.exclude_kernel && !user_mode(regs))
8561 static int perf_swevent_match(struct perf_event *event,
8562 enum perf_type_id type,
8564 struct perf_sample_data *data,
8565 struct pt_regs *regs)
8567 if (event->attr.type != type)
8570 if (event->attr.config != event_id)
8573 if (perf_exclude_event(event, regs))
8579 static inline u64 swevent_hash(u64 type, u32 event_id)
8581 u64 val = event_id | (type << 32);
8583 return hash_64(val, SWEVENT_HLIST_BITS);
8586 static inline struct hlist_head *
8587 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8589 u64 hash = swevent_hash(type, event_id);
8591 return &hlist->heads[hash];
8594 /* For the read side: events when they trigger */
8595 static inline struct hlist_head *
8596 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8598 struct swevent_hlist *hlist;
8600 hlist = rcu_dereference(swhash->swevent_hlist);
8604 return __find_swevent_head(hlist, type, event_id);
8607 /* For the event head insertion and removal in the hlist */
8608 static inline struct hlist_head *
8609 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8611 struct swevent_hlist *hlist;
8612 u32 event_id = event->attr.config;
8613 u64 type = event->attr.type;
8616 * Event scheduling is always serialized against hlist allocation
8617 * and release. Which makes the protected version suitable here.
8618 * The context lock guarantees that.
8620 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8621 lockdep_is_held(&event->ctx->lock));
8625 return __find_swevent_head(hlist, type, event_id);
8628 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8630 struct perf_sample_data *data,
8631 struct pt_regs *regs)
8633 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8634 struct perf_event *event;
8635 struct hlist_head *head;
8638 head = find_swevent_head_rcu(swhash, type, event_id);
8642 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8643 if (perf_swevent_match(event, type, event_id, data, regs))
8644 perf_swevent_event(event, nr, data, regs);
8650 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8652 int perf_swevent_get_recursion_context(void)
8654 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8656 return get_recursion_context(swhash->recursion);
8658 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8660 void perf_swevent_put_recursion_context(int rctx)
8662 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8664 put_recursion_context(swhash->recursion, rctx);
8667 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8669 struct perf_sample_data data;
8671 if (WARN_ON_ONCE(!regs))
8674 perf_sample_data_init(&data, addr, 0);
8675 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8678 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8682 preempt_disable_notrace();
8683 rctx = perf_swevent_get_recursion_context();
8684 if (unlikely(rctx < 0))
8687 ___perf_sw_event(event_id, nr, regs, addr);
8689 perf_swevent_put_recursion_context(rctx);
8691 preempt_enable_notrace();
8694 static void perf_swevent_read(struct perf_event *event)
8698 static int perf_swevent_add(struct perf_event *event, int flags)
8700 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8701 struct hw_perf_event *hwc = &event->hw;
8702 struct hlist_head *head;
8704 if (is_sampling_event(event)) {
8705 hwc->last_period = hwc->sample_period;
8706 perf_swevent_set_period(event);
8709 hwc->state = !(flags & PERF_EF_START);
8711 head = find_swevent_head(swhash, event);
8712 if (WARN_ON_ONCE(!head))
8715 hlist_add_head_rcu(&event->hlist_entry, head);
8716 perf_event_update_userpage(event);
8721 static void perf_swevent_del(struct perf_event *event, int flags)
8723 hlist_del_rcu(&event->hlist_entry);
8726 static void perf_swevent_start(struct perf_event *event, int flags)
8728 event->hw.state = 0;
8731 static void perf_swevent_stop(struct perf_event *event, int flags)
8733 event->hw.state = PERF_HES_STOPPED;
8736 /* Deref the hlist from the update side */
8737 static inline struct swevent_hlist *
8738 swevent_hlist_deref(struct swevent_htable *swhash)
8740 return rcu_dereference_protected(swhash->swevent_hlist,
8741 lockdep_is_held(&swhash->hlist_mutex));
8744 static void swevent_hlist_release(struct swevent_htable *swhash)
8746 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8751 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8752 kfree_rcu(hlist, rcu_head);
8755 static void swevent_hlist_put_cpu(int cpu)
8757 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8759 mutex_lock(&swhash->hlist_mutex);
8761 if (!--swhash->hlist_refcount)
8762 swevent_hlist_release(swhash);
8764 mutex_unlock(&swhash->hlist_mutex);
8767 static void swevent_hlist_put(void)
8771 for_each_possible_cpu(cpu)
8772 swevent_hlist_put_cpu(cpu);
8775 static int swevent_hlist_get_cpu(int cpu)
8777 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8780 mutex_lock(&swhash->hlist_mutex);
8781 if (!swevent_hlist_deref(swhash) &&
8782 cpumask_test_cpu(cpu, perf_online_mask)) {
8783 struct swevent_hlist *hlist;
8785 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8790 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8792 swhash->hlist_refcount++;
8794 mutex_unlock(&swhash->hlist_mutex);
8799 static int swevent_hlist_get(void)
8801 int err, cpu, failed_cpu;
8803 mutex_lock(&pmus_lock);
8804 for_each_possible_cpu(cpu) {
8805 err = swevent_hlist_get_cpu(cpu);
8811 mutex_unlock(&pmus_lock);
8814 for_each_possible_cpu(cpu) {
8815 if (cpu == failed_cpu)
8817 swevent_hlist_put_cpu(cpu);
8819 mutex_unlock(&pmus_lock);
8823 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8825 static void sw_perf_event_destroy(struct perf_event *event)
8827 u64 event_id = event->attr.config;
8829 WARN_ON(event->parent);
8831 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8832 swevent_hlist_put();
8835 static int perf_swevent_init(struct perf_event *event)
8837 u64 event_id = event->attr.config;
8839 if (event->attr.type != PERF_TYPE_SOFTWARE)
8843 * no branch sampling for software events
8845 if (has_branch_stack(event))
8849 case PERF_COUNT_SW_CPU_CLOCK:
8850 case PERF_COUNT_SW_TASK_CLOCK:
8857 if (event_id >= PERF_COUNT_SW_MAX)
8860 if (!event->parent) {
8863 err = swevent_hlist_get();
8867 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8868 event->destroy = sw_perf_event_destroy;
8874 static struct pmu perf_swevent = {
8875 .task_ctx_nr = perf_sw_context,
8877 .capabilities = PERF_PMU_CAP_NO_NMI,
8879 .event_init = perf_swevent_init,
8880 .add = perf_swevent_add,
8881 .del = perf_swevent_del,
8882 .start = perf_swevent_start,
8883 .stop = perf_swevent_stop,
8884 .read = perf_swevent_read,
8887 #ifdef CONFIG_EVENT_TRACING
8889 static int perf_tp_filter_match(struct perf_event *event,
8890 struct perf_sample_data *data)
8892 void *record = data->raw->frag.data;
8894 /* only top level events have filters set */
8896 event = event->parent;
8898 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8903 static int perf_tp_event_match(struct perf_event *event,
8904 struct perf_sample_data *data,
8905 struct pt_regs *regs)
8907 if (event->hw.state & PERF_HES_STOPPED)
8910 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8912 if (event->attr.exclude_kernel && !user_mode(regs))
8915 if (!perf_tp_filter_match(event, data))
8921 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8922 struct trace_event_call *call, u64 count,
8923 struct pt_regs *regs, struct hlist_head *head,
8924 struct task_struct *task)
8926 if (bpf_prog_array_valid(call)) {
8927 *(struct pt_regs **)raw_data = regs;
8928 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8929 perf_swevent_put_recursion_context(rctx);
8933 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8936 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8938 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8939 struct pt_regs *regs, struct hlist_head *head, int rctx,
8940 struct task_struct *task)
8942 struct perf_sample_data data;
8943 struct perf_event *event;
8945 struct perf_raw_record raw = {
8952 perf_sample_data_init(&data, 0, 0);
8955 perf_trace_buf_update(record, event_type);
8957 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8958 if (perf_tp_event_match(event, &data, regs))
8959 perf_swevent_event(event, count, &data, regs);
8963 * If we got specified a target task, also iterate its context and
8964 * deliver this event there too.
8966 if (task && task != current) {
8967 struct perf_event_context *ctx;
8968 struct trace_entry *entry = record;
8971 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8975 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8976 if (event->cpu != smp_processor_id())
8978 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8980 if (event->attr.config != entry->type)
8982 if (perf_tp_event_match(event, &data, regs))
8983 perf_swevent_event(event, count, &data, regs);
8989 perf_swevent_put_recursion_context(rctx);
8991 EXPORT_SYMBOL_GPL(perf_tp_event);
8993 static void tp_perf_event_destroy(struct perf_event *event)
8995 perf_trace_destroy(event);
8998 static int perf_tp_event_init(struct perf_event *event)
9002 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9006 * no branch sampling for tracepoint events
9008 if (has_branch_stack(event))
9011 err = perf_trace_init(event);
9015 event->destroy = tp_perf_event_destroy;
9020 static struct pmu perf_tracepoint = {
9021 .task_ctx_nr = perf_sw_context,
9023 .event_init = perf_tp_event_init,
9024 .add = perf_trace_add,
9025 .del = perf_trace_del,
9026 .start = perf_swevent_start,
9027 .stop = perf_swevent_stop,
9028 .read = perf_swevent_read,
9031 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9033 * Flags in config, used by dynamic PMU kprobe and uprobe
9034 * The flags should match following PMU_FORMAT_ATTR().
9036 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9037 * if not set, create kprobe/uprobe
9039 * The following values specify a reference counter (or semaphore in the
9040 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9041 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9043 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9044 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9046 enum perf_probe_config {
9047 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9048 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9049 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9052 PMU_FORMAT_ATTR(retprobe, "config:0");
9055 #ifdef CONFIG_KPROBE_EVENTS
9056 static struct attribute *kprobe_attrs[] = {
9057 &format_attr_retprobe.attr,
9061 static struct attribute_group kprobe_format_group = {
9063 .attrs = kprobe_attrs,
9066 static const struct attribute_group *kprobe_attr_groups[] = {
9067 &kprobe_format_group,
9071 static int perf_kprobe_event_init(struct perf_event *event);
9072 static struct pmu perf_kprobe = {
9073 .task_ctx_nr = perf_sw_context,
9074 .event_init = perf_kprobe_event_init,
9075 .add = perf_trace_add,
9076 .del = perf_trace_del,
9077 .start = perf_swevent_start,
9078 .stop = perf_swevent_stop,
9079 .read = perf_swevent_read,
9080 .attr_groups = kprobe_attr_groups,
9083 static int perf_kprobe_event_init(struct perf_event *event)
9088 if (event->attr.type != perf_kprobe.type)
9091 if (!capable(CAP_SYS_ADMIN))
9095 * no branch sampling for probe events
9097 if (has_branch_stack(event))
9100 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9101 err = perf_kprobe_init(event, is_retprobe);
9105 event->destroy = perf_kprobe_destroy;
9109 #endif /* CONFIG_KPROBE_EVENTS */
9111 #ifdef CONFIG_UPROBE_EVENTS
9112 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9114 static struct attribute *uprobe_attrs[] = {
9115 &format_attr_retprobe.attr,
9116 &format_attr_ref_ctr_offset.attr,
9120 static struct attribute_group uprobe_format_group = {
9122 .attrs = uprobe_attrs,
9125 static const struct attribute_group *uprobe_attr_groups[] = {
9126 &uprobe_format_group,
9130 static int perf_uprobe_event_init(struct perf_event *event);
9131 static struct pmu perf_uprobe = {
9132 .task_ctx_nr = perf_sw_context,
9133 .event_init = perf_uprobe_event_init,
9134 .add = perf_trace_add,
9135 .del = perf_trace_del,
9136 .start = perf_swevent_start,
9137 .stop = perf_swevent_stop,
9138 .read = perf_swevent_read,
9139 .attr_groups = uprobe_attr_groups,
9142 static int perf_uprobe_event_init(struct perf_event *event)
9145 unsigned long ref_ctr_offset;
9148 if (event->attr.type != perf_uprobe.type)
9151 if (!capable(CAP_SYS_ADMIN))
9155 * no branch sampling for probe events
9157 if (has_branch_stack(event))
9160 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9161 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9162 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9166 event->destroy = perf_uprobe_destroy;
9170 #endif /* CONFIG_UPROBE_EVENTS */
9172 static inline void perf_tp_register(void)
9174 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9175 #ifdef CONFIG_KPROBE_EVENTS
9176 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9178 #ifdef CONFIG_UPROBE_EVENTS
9179 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9183 static void perf_event_free_filter(struct perf_event *event)
9185 ftrace_profile_free_filter(event);
9188 #ifdef CONFIG_BPF_SYSCALL
9189 static void bpf_overflow_handler(struct perf_event *event,
9190 struct perf_sample_data *data,
9191 struct pt_regs *regs)
9193 struct bpf_perf_event_data_kern ctx = {
9199 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9201 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9204 ret = BPF_PROG_RUN(event->prog, &ctx);
9207 __this_cpu_dec(bpf_prog_active);
9212 event->orig_overflow_handler(event, data, regs);
9215 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9217 struct bpf_prog *prog;
9219 if (event->overflow_handler_context)
9220 /* hw breakpoint or kernel counter */
9226 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9228 return PTR_ERR(prog);
9231 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9232 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9236 static void perf_event_free_bpf_handler(struct perf_event *event)
9238 struct bpf_prog *prog = event->prog;
9243 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9248 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9252 static void perf_event_free_bpf_handler(struct perf_event *event)
9258 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9259 * with perf_event_open()
9261 static inline bool perf_event_is_tracing(struct perf_event *event)
9263 if (event->pmu == &perf_tracepoint)
9265 #ifdef CONFIG_KPROBE_EVENTS
9266 if (event->pmu == &perf_kprobe)
9269 #ifdef CONFIG_UPROBE_EVENTS
9270 if (event->pmu == &perf_uprobe)
9276 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9278 bool is_kprobe, is_tracepoint, is_syscall_tp;
9279 struct bpf_prog *prog;
9282 if (!perf_event_is_tracing(event))
9283 return perf_event_set_bpf_handler(event, prog_fd);
9285 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9286 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9287 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9288 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9289 /* bpf programs can only be attached to u/kprobe or tracepoint */
9292 prog = bpf_prog_get(prog_fd);
9294 return PTR_ERR(prog);
9296 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9297 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9298 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9299 /* valid fd, but invalid bpf program type */
9304 /* Kprobe override only works for kprobes, not uprobes. */
9305 if (prog->kprobe_override &&
9306 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9311 if (is_tracepoint || is_syscall_tp) {
9312 int off = trace_event_get_offsets(event->tp_event);
9314 if (prog->aux->max_ctx_offset > off) {
9320 ret = perf_event_attach_bpf_prog(event, prog);
9326 static void perf_event_free_bpf_prog(struct perf_event *event)
9328 if (!perf_event_is_tracing(event)) {
9329 perf_event_free_bpf_handler(event);
9332 perf_event_detach_bpf_prog(event);
9337 static inline void perf_tp_register(void)
9341 static void perf_event_free_filter(struct perf_event *event)
9345 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9350 static void perf_event_free_bpf_prog(struct perf_event *event)
9353 #endif /* CONFIG_EVENT_TRACING */
9355 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9356 void perf_bp_event(struct perf_event *bp, void *data)
9358 struct perf_sample_data sample;
9359 struct pt_regs *regs = data;
9361 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9363 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9364 perf_swevent_event(bp, 1, &sample, regs);
9369 * Allocate a new address filter
9371 static struct perf_addr_filter *
9372 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9374 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9375 struct perf_addr_filter *filter;
9377 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9381 INIT_LIST_HEAD(&filter->entry);
9382 list_add_tail(&filter->entry, filters);
9387 static void free_filters_list(struct list_head *filters)
9389 struct perf_addr_filter *filter, *iter;
9391 list_for_each_entry_safe(filter, iter, filters, entry) {
9392 path_put(&filter->path);
9393 list_del(&filter->entry);
9399 * Free existing address filters and optionally install new ones
9401 static void perf_addr_filters_splice(struct perf_event *event,
9402 struct list_head *head)
9404 unsigned long flags;
9407 if (!has_addr_filter(event))
9410 /* don't bother with children, they don't have their own filters */
9414 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9416 list_splice_init(&event->addr_filters.list, &list);
9418 list_splice(head, &event->addr_filters.list);
9420 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9422 free_filters_list(&list);
9426 * Scan through mm's vmas and see if one of them matches the
9427 * @filter; if so, adjust filter's address range.
9428 * Called with mm::mmap_sem down for reading.
9430 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9431 struct mm_struct *mm,
9432 struct perf_addr_filter_range *fr)
9434 struct vm_area_struct *vma;
9436 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9440 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9446 * Update event's address range filters based on the
9447 * task's existing mappings, if any.
9449 static void perf_event_addr_filters_apply(struct perf_event *event)
9451 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9452 struct task_struct *task = READ_ONCE(event->ctx->task);
9453 struct perf_addr_filter *filter;
9454 struct mm_struct *mm = NULL;
9455 unsigned int count = 0;
9456 unsigned long flags;
9459 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9460 * will stop on the parent's child_mutex that our caller is also holding
9462 if (task == TASK_TOMBSTONE)
9465 if (ifh->nr_file_filters) {
9466 mm = get_task_mm(event->ctx->task);
9470 down_read(&mm->mmap_sem);
9473 raw_spin_lock_irqsave(&ifh->lock, flags);
9474 list_for_each_entry(filter, &ifh->list, entry) {
9475 if (filter->path.dentry) {
9477 * Adjust base offset if the filter is associated to a
9478 * binary that needs to be mapped:
9480 event->addr_filter_ranges[count].start = 0;
9481 event->addr_filter_ranges[count].size = 0;
9483 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9485 event->addr_filter_ranges[count].start = filter->offset;
9486 event->addr_filter_ranges[count].size = filter->size;
9492 event->addr_filters_gen++;
9493 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9495 if (ifh->nr_file_filters) {
9496 up_read(&mm->mmap_sem);
9502 perf_event_stop(event, 1);
9506 * Address range filtering: limiting the data to certain
9507 * instruction address ranges. Filters are ioctl()ed to us from
9508 * userspace as ascii strings.
9510 * Filter string format:
9513 * where ACTION is one of the
9514 * * "filter": limit the trace to this region
9515 * * "start": start tracing from this address
9516 * * "stop": stop tracing at this address/region;
9518 * * for kernel addresses: <start address>[/<size>]
9519 * * for object files: <start address>[/<size>]@</path/to/object/file>
9521 * if <size> is not specified or is zero, the range is treated as a single
9522 * address; not valid for ACTION=="filter".
9536 IF_STATE_ACTION = 0,
9541 static const match_table_t if_tokens = {
9542 { IF_ACT_FILTER, "filter" },
9543 { IF_ACT_START, "start" },
9544 { IF_ACT_STOP, "stop" },
9545 { IF_SRC_FILE, "%u/%u@%s" },
9546 { IF_SRC_KERNEL, "%u/%u" },
9547 { IF_SRC_FILEADDR, "%u@%s" },
9548 { IF_SRC_KERNELADDR, "%u" },
9549 { IF_ACT_NONE, NULL },
9553 * Address filter string parser
9556 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9557 struct list_head *filters)
9559 struct perf_addr_filter *filter = NULL;
9560 char *start, *orig, *filename = NULL;
9561 substring_t args[MAX_OPT_ARGS];
9562 int state = IF_STATE_ACTION, token;
9563 unsigned int kernel = 0;
9566 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9570 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9571 static const enum perf_addr_filter_action_t actions[] = {
9572 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9573 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9574 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9581 /* filter definition begins */
9582 if (state == IF_STATE_ACTION) {
9583 filter = perf_addr_filter_new(event, filters);
9588 token = match_token(start, if_tokens, args);
9593 if (state != IF_STATE_ACTION)
9596 filter->action = actions[token];
9597 state = IF_STATE_SOURCE;
9600 case IF_SRC_KERNELADDR:
9605 case IF_SRC_FILEADDR:
9607 if (state != IF_STATE_SOURCE)
9611 ret = kstrtoul(args[0].from, 0, &filter->offset);
9615 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9617 ret = kstrtoul(args[1].from, 0, &filter->size);
9622 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9623 int fpos = token == IF_SRC_FILE ? 2 : 1;
9625 filename = match_strdup(&args[fpos]);
9632 state = IF_STATE_END;
9640 * Filter definition is fully parsed, validate and install it.
9641 * Make sure that it doesn't contradict itself or the event's
9644 if (state == IF_STATE_END) {
9646 if (kernel && event->attr.exclude_kernel)
9650 * ACTION "filter" must have a non-zero length region
9653 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9662 * For now, we only support file-based filters
9663 * in per-task events; doing so for CPU-wide
9664 * events requires additional context switching
9665 * trickery, since same object code will be
9666 * mapped at different virtual addresses in
9667 * different processes.
9670 if (!event->ctx->task)
9671 goto fail_free_name;
9673 /* look up the path and grab its inode */
9674 ret = kern_path(filename, LOOKUP_FOLLOW,
9677 goto fail_free_name;
9683 if (!filter->path.dentry ||
9684 !S_ISREG(d_inode(filter->path.dentry)
9688 event->addr_filters.nr_file_filters++;
9691 /* ready to consume more filters */
9692 state = IF_STATE_ACTION;
9697 if (state != IF_STATE_ACTION)
9707 free_filters_list(filters);
9714 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9720 * Since this is called in perf_ioctl() path, we're already holding
9723 lockdep_assert_held(&event->ctx->mutex);
9725 if (WARN_ON_ONCE(event->parent))
9728 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9730 goto fail_clear_files;
9732 ret = event->pmu->addr_filters_validate(&filters);
9734 goto fail_free_filters;
9736 /* remove existing filters, if any */
9737 perf_addr_filters_splice(event, &filters);
9739 /* install new filters */
9740 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9745 free_filters_list(&filters);
9748 event->addr_filters.nr_file_filters = 0;
9753 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9758 filter_str = strndup_user(arg, PAGE_SIZE);
9759 if (IS_ERR(filter_str))
9760 return PTR_ERR(filter_str);
9762 #ifdef CONFIG_EVENT_TRACING
9763 if (perf_event_is_tracing(event)) {
9764 struct perf_event_context *ctx = event->ctx;
9767 * Beware, here be dragons!!
9769 * the tracepoint muck will deadlock against ctx->mutex, but
9770 * the tracepoint stuff does not actually need it. So
9771 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9772 * already have a reference on ctx.
9774 * This can result in event getting moved to a different ctx,
9775 * but that does not affect the tracepoint state.
9777 mutex_unlock(&ctx->mutex);
9778 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9779 mutex_lock(&ctx->mutex);
9782 if (has_addr_filter(event))
9783 ret = perf_event_set_addr_filter(event, filter_str);
9790 * hrtimer based swevent callback
9793 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9795 enum hrtimer_restart ret = HRTIMER_RESTART;
9796 struct perf_sample_data data;
9797 struct pt_regs *regs;
9798 struct perf_event *event;
9801 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9803 if (event->state != PERF_EVENT_STATE_ACTIVE)
9804 return HRTIMER_NORESTART;
9806 event->pmu->read(event);
9808 perf_sample_data_init(&data, 0, event->hw.last_period);
9809 regs = get_irq_regs();
9811 if (regs && !perf_exclude_event(event, regs)) {
9812 if (!(event->attr.exclude_idle && is_idle_task(current)))
9813 if (__perf_event_overflow(event, 1, &data, regs))
9814 ret = HRTIMER_NORESTART;
9817 period = max_t(u64, 10000, event->hw.sample_period);
9818 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9823 static void perf_swevent_start_hrtimer(struct perf_event *event)
9825 struct hw_perf_event *hwc = &event->hw;
9828 if (!is_sampling_event(event))
9831 period = local64_read(&hwc->period_left);
9836 local64_set(&hwc->period_left, 0);
9838 period = max_t(u64, 10000, hwc->sample_period);
9840 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9841 HRTIMER_MODE_REL_PINNED_HARD);
9844 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9846 struct hw_perf_event *hwc = &event->hw;
9848 if (is_sampling_event(event)) {
9849 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9850 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9852 hrtimer_cancel(&hwc->hrtimer);
9856 static void perf_swevent_init_hrtimer(struct perf_event *event)
9858 struct hw_perf_event *hwc = &event->hw;
9860 if (!is_sampling_event(event))
9863 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
9864 hwc->hrtimer.function = perf_swevent_hrtimer;
9867 * Since hrtimers have a fixed rate, we can do a static freq->period
9868 * mapping and avoid the whole period adjust feedback stuff.
9870 if (event->attr.freq) {
9871 long freq = event->attr.sample_freq;
9873 event->attr.sample_period = NSEC_PER_SEC / freq;
9874 hwc->sample_period = event->attr.sample_period;
9875 local64_set(&hwc->period_left, hwc->sample_period);
9876 hwc->last_period = hwc->sample_period;
9877 event->attr.freq = 0;
9882 * Software event: cpu wall time clock
9885 static void cpu_clock_event_update(struct perf_event *event)
9890 now = local_clock();
9891 prev = local64_xchg(&event->hw.prev_count, now);
9892 local64_add(now - prev, &event->count);
9895 static void cpu_clock_event_start(struct perf_event *event, int flags)
9897 local64_set(&event->hw.prev_count, local_clock());
9898 perf_swevent_start_hrtimer(event);
9901 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9903 perf_swevent_cancel_hrtimer(event);
9904 cpu_clock_event_update(event);
9907 static int cpu_clock_event_add(struct perf_event *event, int flags)
9909 if (flags & PERF_EF_START)
9910 cpu_clock_event_start(event, flags);
9911 perf_event_update_userpage(event);
9916 static void cpu_clock_event_del(struct perf_event *event, int flags)
9918 cpu_clock_event_stop(event, flags);
9921 static void cpu_clock_event_read(struct perf_event *event)
9923 cpu_clock_event_update(event);
9926 static int cpu_clock_event_init(struct perf_event *event)
9928 if (event->attr.type != PERF_TYPE_SOFTWARE)
9931 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9935 * no branch sampling for software events
9937 if (has_branch_stack(event))
9940 perf_swevent_init_hrtimer(event);
9945 static struct pmu perf_cpu_clock = {
9946 .task_ctx_nr = perf_sw_context,
9948 .capabilities = PERF_PMU_CAP_NO_NMI,
9950 .event_init = cpu_clock_event_init,
9951 .add = cpu_clock_event_add,
9952 .del = cpu_clock_event_del,
9953 .start = cpu_clock_event_start,
9954 .stop = cpu_clock_event_stop,
9955 .read = cpu_clock_event_read,
9959 * Software event: task time clock
9962 static void task_clock_event_update(struct perf_event *event, u64 now)
9967 prev = local64_xchg(&event->hw.prev_count, now);
9969 local64_add(delta, &event->count);
9972 static void task_clock_event_start(struct perf_event *event, int flags)
9974 local64_set(&event->hw.prev_count, event->ctx->time);
9975 perf_swevent_start_hrtimer(event);
9978 static void task_clock_event_stop(struct perf_event *event, int flags)
9980 perf_swevent_cancel_hrtimer(event);
9981 task_clock_event_update(event, event->ctx->time);
9984 static int task_clock_event_add(struct perf_event *event, int flags)
9986 if (flags & PERF_EF_START)
9987 task_clock_event_start(event, flags);
9988 perf_event_update_userpage(event);
9993 static void task_clock_event_del(struct perf_event *event, int flags)
9995 task_clock_event_stop(event, PERF_EF_UPDATE);
9998 static void task_clock_event_read(struct perf_event *event)
10000 u64 now = perf_clock();
10001 u64 delta = now - event->ctx->timestamp;
10002 u64 time = event->ctx->time + delta;
10004 task_clock_event_update(event, time);
10007 static int task_clock_event_init(struct perf_event *event)
10009 if (event->attr.type != PERF_TYPE_SOFTWARE)
10012 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10016 * no branch sampling for software events
10018 if (has_branch_stack(event))
10019 return -EOPNOTSUPP;
10021 perf_swevent_init_hrtimer(event);
10026 static struct pmu perf_task_clock = {
10027 .task_ctx_nr = perf_sw_context,
10029 .capabilities = PERF_PMU_CAP_NO_NMI,
10031 .event_init = task_clock_event_init,
10032 .add = task_clock_event_add,
10033 .del = task_clock_event_del,
10034 .start = task_clock_event_start,
10035 .stop = task_clock_event_stop,
10036 .read = task_clock_event_read,
10039 static void perf_pmu_nop_void(struct pmu *pmu)
10043 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10047 static int perf_pmu_nop_int(struct pmu *pmu)
10052 static int perf_event_nop_int(struct perf_event *event, u64 value)
10057 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10059 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10061 __this_cpu_write(nop_txn_flags, flags);
10063 if (flags & ~PERF_PMU_TXN_ADD)
10066 perf_pmu_disable(pmu);
10069 static int perf_pmu_commit_txn(struct pmu *pmu)
10071 unsigned int flags = __this_cpu_read(nop_txn_flags);
10073 __this_cpu_write(nop_txn_flags, 0);
10075 if (flags & ~PERF_PMU_TXN_ADD)
10078 perf_pmu_enable(pmu);
10082 static void perf_pmu_cancel_txn(struct pmu *pmu)
10084 unsigned int flags = __this_cpu_read(nop_txn_flags);
10086 __this_cpu_write(nop_txn_flags, 0);
10088 if (flags & ~PERF_PMU_TXN_ADD)
10091 perf_pmu_enable(pmu);
10094 static int perf_event_idx_default(struct perf_event *event)
10100 * Ensures all contexts with the same task_ctx_nr have the same
10101 * pmu_cpu_context too.
10103 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10110 list_for_each_entry(pmu, &pmus, entry) {
10111 if (pmu->task_ctx_nr == ctxn)
10112 return pmu->pmu_cpu_context;
10118 static void free_pmu_context(struct pmu *pmu)
10121 * Static contexts such as perf_sw_context have a global lifetime
10122 * and may be shared between different PMUs. Avoid freeing them
10123 * when a single PMU is going away.
10125 if (pmu->task_ctx_nr > perf_invalid_context)
10128 free_percpu(pmu->pmu_cpu_context);
10132 * Let userspace know that this PMU supports address range filtering:
10134 static ssize_t nr_addr_filters_show(struct device *dev,
10135 struct device_attribute *attr,
10138 struct pmu *pmu = dev_get_drvdata(dev);
10140 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10142 DEVICE_ATTR_RO(nr_addr_filters);
10144 static struct idr pmu_idr;
10147 type_show(struct device *dev, struct device_attribute *attr, char *page)
10149 struct pmu *pmu = dev_get_drvdata(dev);
10151 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10153 static DEVICE_ATTR_RO(type);
10156 perf_event_mux_interval_ms_show(struct device *dev,
10157 struct device_attribute *attr,
10160 struct pmu *pmu = dev_get_drvdata(dev);
10162 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10165 static DEFINE_MUTEX(mux_interval_mutex);
10168 perf_event_mux_interval_ms_store(struct device *dev,
10169 struct device_attribute *attr,
10170 const char *buf, size_t count)
10172 struct pmu *pmu = dev_get_drvdata(dev);
10173 int timer, cpu, ret;
10175 ret = kstrtoint(buf, 0, &timer);
10182 /* same value, noting to do */
10183 if (timer == pmu->hrtimer_interval_ms)
10186 mutex_lock(&mux_interval_mutex);
10187 pmu->hrtimer_interval_ms = timer;
10189 /* update all cpuctx for this PMU */
10191 for_each_online_cpu(cpu) {
10192 struct perf_cpu_context *cpuctx;
10193 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10194 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10196 cpu_function_call(cpu,
10197 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10199 cpus_read_unlock();
10200 mutex_unlock(&mux_interval_mutex);
10204 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10206 static struct attribute *pmu_dev_attrs[] = {
10207 &dev_attr_type.attr,
10208 &dev_attr_perf_event_mux_interval_ms.attr,
10211 ATTRIBUTE_GROUPS(pmu_dev);
10213 static int pmu_bus_running;
10214 static struct bus_type pmu_bus = {
10215 .name = "event_source",
10216 .dev_groups = pmu_dev_groups,
10219 static void pmu_dev_release(struct device *dev)
10224 static int pmu_dev_alloc(struct pmu *pmu)
10228 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10232 pmu->dev->groups = pmu->attr_groups;
10233 device_initialize(pmu->dev);
10234 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10238 dev_set_drvdata(pmu->dev, pmu);
10239 pmu->dev->bus = &pmu_bus;
10240 pmu->dev->release = pmu_dev_release;
10241 ret = device_add(pmu->dev);
10245 /* For PMUs with address filters, throw in an extra attribute: */
10246 if (pmu->nr_addr_filters)
10247 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10252 if (pmu->attr_update)
10253 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10262 device_del(pmu->dev);
10265 put_device(pmu->dev);
10269 static struct lock_class_key cpuctx_mutex;
10270 static struct lock_class_key cpuctx_lock;
10272 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10274 int cpu, ret, max = PERF_TYPE_MAX;
10276 mutex_lock(&pmus_lock);
10278 pmu->pmu_disable_count = alloc_percpu(int);
10279 if (!pmu->pmu_disable_count)
10287 if (type != PERF_TYPE_SOFTWARE) {
10291 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
10295 WARN_ON(type >= 0 && ret != type);
10301 if (pmu_bus_running) {
10302 ret = pmu_dev_alloc(pmu);
10308 if (pmu->task_ctx_nr == perf_hw_context) {
10309 static int hw_context_taken = 0;
10312 * Other than systems with heterogeneous CPUs, it never makes
10313 * sense for two PMUs to share perf_hw_context. PMUs which are
10314 * uncore must use perf_invalid_context.
10316 if (WARN_ON_ONCE(hw_context_taken &&
10317 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10318 pmu->task_ctx_nr = perf_invalid_context;
10320 hw_context_taken = 1;
10323 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10324 if (pmu->pmu_cpu_context)
10325 goto got_cpu_context;
10328 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10329 if (!pmu->pmu_cpu_context)
10332 for_each_possible_cpu(cpu) {
10333 struct perf_cpu_context *cpuctx;
10335 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10336 __perf_event_init_context(&cpuctx->ctx);
10337 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10338 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10339 cpuctx->ctx.pmu = pmu;
10340 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10342 __perf_mux_hrtimer_init(cpuctx, cpu);
10346 if (!pmu->start_txn) {
10347 if (pmu->pmu_enable) {
10349 * If we have pmu_enable/pmu_disable calls, install
10350 * transaction stubs that use that to try and batch
10351 * hardware accesses.
10353 pmu->start_txn = perf_pmu_start_txn;
10354 pmu->commit_txn = perf_pmu_commit_txn;
10355 pmu->cancel_txn = perf_pmu_cancel_txn;
10357 pmu->start_txn = perf_pmu_nop_txn;
10358 pmu->commit_txn = perf_pmu_nop_int;
10359 pmu->cancel_txn = perf_pmu_nop_void;
10363 if (!pmu->pmu_enable) {
10364 pmu->pmu_enable = perf_pmu_nop_void;
10365 pmu->pmu_disable = perf_pmu_nop_void;
10368 if (!pmu->check_period)
10369 pmu->check_period = perf_event_nop_int;
10371 if (!pmu->event_idx)
10372 pmu->event_idx = perf_event_idx_default;
10375 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
10376 * since these cannot be in the IDR. This way the linear search
10377 * is fast, provided a valid software event is provided.
10379 if (type == PERF_TYPE_SOFTWARE || !name)
10380 list_add_rcu(&pmu->entry, &pmus);
10382 list_add_tail_rcu(&pmu->entry, &pmus);
10384 atomic_set(&pmu->exclusive_cnt, 0);
10387 mutex_unlock(&pmus_lock);
10392 device_del(pmu->dev);
10393 put_device(pmu->dev);
10396 if (pmu->type != PERF_TYPE_SOFTWARE)
10397 idr_remove(&pmu_idr, pmu->type);
10400 free_percpu(pmu->pmu_disable_count);
10403 EXPORT_SYMBOL_GPL(perf_pmu_register);
10405 void perf_pmu_unregister(struct pmu *pmu)
10407 mutex_lock(&pmus_lock);
10408 list_del_rcu(&pmu->entry);
10411 * We dereference the pmu list under both SRCU and regular RCU, so
10412 * synchronize against both of those.
10414 synchronize_srcu(&pmus_srcu);
10417 free_percpu(pmu->pmu_disable_count);
10418 if (pmu->type != PERF_TYPE_SOFTWARE)
10419 idr_remove(&pmu_idr, pmu->type);
10420 if (pmu_bus_running) {
10421 if (pmu->nr_addr_filters)
10422 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10423 device_del(pmu->dev);
10424 put_device(pmu->dev);
10426 free_pmu_context(pmu);
10427 mutex_unlock(&pmus_lock);
10429 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10431 static inline bool has_extended_regs(struct perf_event *event)
10433 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10434 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10437 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10439 struct perf_event_context *ctx = NULL;
10442 if (!try_module_get(pmu->module))
10446 * A number of pmu->event_init() methods iterate the sibling_list to,
10447 * for example, validate if the group fits on the PMU. Therefore,
10448 * if this is a sibling event, acquire the ctx->mutex to protect
10449 * the sibling_list.
10451 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10453 * This ctx->mutex can nest when we're called through
10454 * inheritance. See the perf_event_ctx_lock_nested() comment.
10456 ctx = perf_event_ctx_lock_nested(event->group_leader,
10457 SINGLE_DEPTH_NESTING);
10462 ret = pmu->event_init(event);
10465 perf_event_ctx_unlock(event->group_leader, ctx);
10468 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10469 has_extended_regs(event))
10472 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10473 event_has_any_exclude_flag(event))
10476 if (ret && event->destroy)
10477 event->destroy(event);
10481 module_put(pmu->module);
10486 static struct pmu *perf_init_event(struct perf_event *event)
10488 int idx, type, ret;
10491 idx = srcu_read_lock(&pmus_srcu);
10493 /* Try parent's PMU first: */
10494 if (event->parent && event->parent->pmu) {
10495 pmu = event->parent->pmu;
10496 ret = perf_try_init_event(pmu, event);
10502 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
10503 * are often aliases for PERF_TYPE_RAW.
10505 type = event->attr.type;
10506 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
10507 type = PERF_TYPE_RAW;
10511 pmu = idr_find(&pmu_idr, type);
10514 ret = perf_try_init_event(pmu, event);
10515 if (ret == -ENOENT && event->attr.type != type) {
10516 type = event->attr.type;
10521 pmu = ERR_PTR(ret);
10526 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
10527 ret = perf_try_init_event(pmu, event);
10531 if (ret != -ENOENT) {
10532 pmu = ERR_PTR(ret);
10536 pmu = ERR_PTR(-ENOENT);
10538 srcu_read_unlock(&pmus_srcu, idx);
10543 static void attach_sb_event(struct perf_event *event)
10545 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10547 raw_spin_lock(&pel->lock);
10548 list_add_rcu(&event->sb_list, &pel->list);
10549 raw_spin_unlock(&pel->lock);
10553 * We keep a list of all !task (and therefore per-cpu) events
10554 * that need to receive side-band records.
10556 * This avoids having to scan all the various PMU per-cpu contexts
10557 * looking for them.
10559 static void account_pmu_sb_event(struct perf_event *event)
10561 if (is_sb_event(event))
10562 attach_sb_event(event);
10565 static void account_event_cpu(struct perf_event *event, int cpu)
10570 if (is_cgroup_event(event))
10571 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10574 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10575 static void account_freq_event_nohz(void)
10577 #ifdef CONFIG_NO_HZ_FULL
10578 /* Lock so we don't race with concurrent unaccount */
10579 spin_lock(&nr_freq_lock);
10580 if (atomic_inc_return(&nr_freq_events) == 1)
10581 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10582 spin_unlock(&nr_freq_lock);
10586 static void account_freq_event(void)
10588 if (tick_nohz_full_enabled())
10589 account_freq_event_nohz();
10591 atomic_inc(&nr_freq_events);
10595 static void account_event(struct perf_event *event)
10602 if (event->attach_state & PERF_ATTACH_TASK)
10604 if (event->attr.mmap || event->attr.mmap_data)
10605 atomic_inc(&nr_mmap_events);
10606 if (event->attr.comm)
10607 atomic_inc(&nr_comm_events);
10608 if (event->attr.namespaces)
10609 atomic_inc(&nr_namespaces_events);
10610 if (event->attr.task)
10611 atomic_inc(&nr_task_events);
10612 if (event->attr.freq)
10613 account_freq_event();
10614 if (event->attr.context_switch) {
10615 atomic_inc(&nr_switch_events);
10618 if (has_branch_stack(event))
10620 if (is_cgroup_event(event))
10622 if (event->attr.ksymbol)
10623 atomic_inc(&nr_ksymbol_events);
10624 if (event->attr.bpf_event)
10625 atomic_inc(&nr_bpf_events);
10629 * We need the mutex here because static_branch_enable()
10630 * must complete *before* the perf_sched_count increment
10633 if (atomic_inc_not_zero(&perf_sched_count))
10636 mutex_lock(&perf_sched_mutex);
10637 if (!atomic_read(&perf_sched_count)) {
10638 static_branch_enable(&perf_sched_events);
10640 * Guarantee that all CPUs observe they key change and
10641 * call the perf scheduling hooks before proceeding to
10642 * install events that need them.
10647 * Now that we have waited for the sync_sched(), allow further
10648 * increments to by-pass the mutex.
10650 atomic_inc(&perf_sched_count);
10651 mutex_unlock(&perf_sched_mutex);
10655 account_event_cpu(event, event->cpu);
10657 account_pmu_sb_event(event);
10661 * Allocate and initialize an event structure
10663 static struct perf_event *
10664 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10665 struct task_struct *task,
10666 struct perf_event *group_leader,
10667 struct perf_event *parent_event,
10668 perf_overflow_handler_t overflow_handler,
10669 void *context, int cgroup_fd)
10672 struct perf_event *event;
10673 struct hw_perf_event *hwc;
10674 long err = -EINVAL;
10676 if ((unsigned)cpu >= nr_cpu_ids) {
10677 if (!task || cpu != -1)
10678 return ERR_PTR(-EINVAL);
10681 event = kzalloc(sizeof(*event), GFP_KERNEL);
10683 return ERR_PTR(-ENOMEM);
10686 * Single events are their own group leaders, with an
10687 * empty sibling list:
10690 group_leader = event;
10692 mutex_init(&event->child_mutex);
10693 INIT_LIST_HEAD(&event->child_list);
10695 INIT_LIST_HEAD(&event->event_entry);
10696 INIT_LIST_HEAD(&event->sibling_list);
10697 INIT_LIST_HEAD(&event->active_list);
10698 init_event_group(event);
10699 INIT_LIST_HEAD(&event->rb_entry);
10700 INIT_LIST_HEAD(&event->active_entry);
10701 INIT_LIST_HEAD(&event->addr_filters.list);
10702 INIT_HLIST_NODE(&event->hlist_entry);
10705 init_waitqueue_head(&event->waitq);
10706 event->pending_disable = -1;
10707 init_irq_work(&event->pending, perf_pending_event);
10709 mutex_init(&event->mmap_mutex);
10710 raw_spin_lock_init(&event->addr_filters.lock);
10712 atomic_long_set(&event->refcount, 1);
10714 event->attr = *attr;
10715 event->group_leader = group_leader;
10719 event->parent = parent_event;
10721 event->ns = get_pid_ns(task_active_pid_ns(current));
10722 event->id = atomic64_inc_return(&perf_event_id);
10724 event->state = PERF_EVENT_STATE_INACTIVE;
10727 event->attach_state = PERF_ATTACH_TASK;
10729 * XXX pmu::event_init needs to know what task to account to
10730 * and we cannot use the ctx information because we need the
10731 * pmu before we get a ctx.
10733 event->hw.target = get_task_struct(task);
10736 event->clock = &local_clock;
10738 event->clock = parent_event->clock;
10740 if (!overflow_handler && parent_event) {
10741 overflow_handler = parent_event->overflow_handler;
10742 context = parent_event->overflow_handler_context;
10743 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10744 if (overflow_handler == bpf_overflow_handler) {
10745 struct bpf_prog *prog = parent_event->prog;
10747 bpf_prog_inc(prog);
10748 event->prog = prog;
10749 event->orig_overflow_handler =
10750 parent_event->orig_overflow_handler;
10755 if (overflow_handler) {
10756 event->overflow_handler = overflow_handler;
10757 event->overflow_handler_context = context;
10758 } else if (is_write_backward(event)){
10759 event->overflow_handler = perf_event_output_backward;
10760 event->overflow_handler_context = NULL;
10762 event->overflow_handler = perf_event_output_forward;
10763 event->overflow_handler_context = NULL;
10766 perf_event__state_init(event);
10771 hwc->sample_period = attr->sample_period;
10772 if (attr->freq && attr->sample_freq)
10773 hwc->sample_period = 1;
10774 hwc->last_period = hwc->sample_period;
10776 local64_set(&hwc->period_left, hwc->sample_period);
10779 * We currently do not support PERF_SAMPLE_READ on inherited events.
10780 * See perf_output_read().
10782 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10785 if (!has_branch_stack(event))
10786 event->attr.branch_sample_type = 0;
10788 if (cgroup_fd != -1) {
10789 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10794 pmu = perf_init_event(event);
10796 err = PTR_ERR(pmu);
10801 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
10802 * be different on other CPUs in the uncore mask.
10804 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
10809 if (event->attr.aux_output &&
10810 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10815 err = exclusive_event_init(event);
10819 if (has_addr_filter(event)) {
10820 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10821 sizeof(struct perf_addr_filter_range),
10823 if (!event->addr_filter_ranges) {
10829 * Clone the parent's vma offsets: they are valid until exec()
10830 * even if the mm is not shared with the parent.
10832 if (event->parent) {
10833 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10835 raw_spin_lock_irq(&ifh->lock);
10836 memcpy(event->addr_filter_ranges,
10837 event->parent->addr_filter_ranges,
10838 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10839 raw_spin_unlock_irq(&ifh->lock);
10842 /* force hw sync on the address filters */
10843 event->addr_filters_gen = 1;
10846 if (!event->parent) {
10847 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10848 err = get_callchain_buffers(attr->sample_max_stack);
10850 goto err_addr_filters;
10854 err = security_perf_event_alloc(event);
10856 goto err_callchain_buffer;
10858 /* symmetric to unaccount_event() in _free_event() */
10859 account_event(event);
10863 err_callchain_buffer:
10864 if (!event->parent) {
10865 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
10866 put_callchain_buffers();
10869 kfree(event->addr_filter_ranges);
10872 exclusive_event_destroy(event);
10875 if (event->destroy)
10876 event->destroy(event);
10877 module_put(pmu->module);
10879 if (is_cgroup_event(event))
10880 perf_detach_cgroup(event);
10882 put_pid_ns(event->ns);
10883 if (event->hw.target)
10884 put_task_struct(event->hw.target);
10887 return ERR_PTR(err);
10890 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10891 struct perf_event_attr *attr)
10896 /* Zero the full structure, so that a short copy will be nice. */
10897 memset(attr, 0, sizeof(*attr));
10899 ret = get_user(size, &uattr->size);
10903 /* ABI compatibility quirk: */
10905 size = PERF_ATTR_SIZE_VER0;
10906 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
10909 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
10918 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
10921 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10924 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10927 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10928 u64 mask = attr->branch_sample_type;
10930 /* only using defined bits */
10931 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10934 /* at least one branch bit must be set */
10935 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10938 /* propagate priv level, when not set for branch */
10939 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10941 /* exclude_kernel checked on syscall entry */
10942 if (!attr->exclude_kernel)
10943 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10945 if (!attr->exclude_user)
10946 mask |= PERF_SAMPLE_BRANCH_USER;
10948 if (!attr->exclude_hv)
10949 mask |= PERF_SAMPLE_BRANCH_HV;
10951 * adjust user setting (for HW filter setup)
10953 attr->branch_sample_type = mask;
10955 /* privileged levels capture (kernel, hv): check permissions */
10956 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
10957 ret = perf_allow_kernel(attr);
10963 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10964 ret = perf_reg_validate(attr->sample_regs_user);
10969 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10970 if (!arch_perf_have_user_stack_dump())
10974 * We have __u32 type for the size, but so far
10975 * we can only use __u16 as maximum due to the
10976 * __u16 sample size limit.
10978 if (attr->sample_stack_user >= USHRT_MAX)
10980 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10984 if (!attr->sample_max_stack)
10985 attr->sample_max_stack = sysctl_perf_event_max_stack;
10987 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10988 ret = perf_reg_validate(attr->sample_regs_intr);
10993 put_user(sizeof(*attr), &uattr->size);
10999 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11001 struct ring_buffer *rb = NULL;
11007 /* don't allow circular references */
11008 if (event == output_event)
11012 * Don't allow cross-cpu buffers
11014 if (output_event->cpu != event->cpu)
11018 * If its not a per-cpu rb, it must be the same task.
11020 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11024 * Mixing clocks in the same buffer is trouble you don't need.
11026 if (output_event->clock != event->clock)
11030 * Either writing ring buffer from beginning or from end.
11031 * Mixing is not allowed.
11033 if (is_write_backward(output_event) != is_write_backward(event))
11037 * If both events generate aux data, they must be on the same PMU
11039 if (has_aux(event) && has_aux(output_event) &&
11040 event->pmu != output_event->pmu)
11044 mutex_lock(&event->mmap_mutex);
11045 /* Can't redirect output if we've got an active mmap() */
11046 if (atomic_read(&event->mmap_count))
11049 if (output_event) {
11050 /* get the rb we want to redirect to */
11051 rb = ring_buffer_get(output_event);
11056 ring_buffer_attach(event, rb);
11060 mutex_unlock(&event->mmap_mutex);
11066 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11072 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11075 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11077 bool nmi_safe = false;
11080 case CLOCK_MONOTONIC:
11081 event->clock = &ktime_get_mono_fast_ns;
11085 case CLOCK_MONOTONIC_RAW:
11086 event->clock = &ktime_get_raw_fast_ns;
11090 case CLOCK_REALTIME:
11091 event->clock = &ktime_get_real_ns;
11094 case CLOCK_BOOTTIME:
11095 event->clock = &ktime_get_boottime_ns;
11099 event->clock = &ktime_get_clocktai_ns;
11106 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11113 * Variation on perf_event_ctx_lock_nested(), except we take two context
11116 static struct perf_event_context *
11117 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11118 struct perf_event_context *ctx)
11120 struct perf_event_context *gctx;
11124 gctx = READ_ONCE(group_leader->ctx);
11125 if (!refcount_inc_not_zero(&gctx->refcount)) {
11131 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11133 if (group_leader->ctx != gctx) {
11134 mutex_unlock(&ctx->mutex);
11135 mutex_unlock(&gctx->mutex);
11144 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11146 * @attr_uptr: event_id type attributes for monitoring/sampling
11149 * @group_fd: group leader event fd
11151 SYSCALL_DEFINE5(perf_event_open,
11152 struct perf_event_attr __user *, attr_uptr,
11153 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11155 struct perf_event *group_leader = NULL, *output_event = NULL;
11156 struct perf_event *event, *sibling;
11157 struct perf_event_attr attr;
11158 struct perf_event_context *ctx, *uninitialized_var(gctx);
11159 struct file *event_file = NULL;
11160 struct fd group = {NULL, 0};
11161 struct task_struct *task = NULL;
11164 int move_group = 0;
11166 int f_flags = O_RDWR;
11167 int cgroup_fd = -1;
11169 /* for future expandability... */
11170 if (flags & ~PERF_FLAG_ALL)
11173 /* Do we allow access to perf_event_open(2) ? */
11174 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11178 err = perf_copy_attr(attr_uptr, &attr);
11182 if (!attr.exclude_kernel) {
11183 err = perf_allow_kernel(&attr);
11188 if (attr.namespaces) {
11189 if (!capable(CAP_SYS_ADMIN))
11194 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11197 if (attr.sample_period & (1ULL << 63))
11201 /* Only privileged users can get physical addresses */
11202 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11203 err = perf_allow_kernel(&attr);
11208 err = security_locked_down(LOCKDOWN_PERF);
11209 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
11210 /* REGS_INTR can leak data, lockdown must prevent this */
11216 * In cgroup mode, the pid argument is used to pass the fd
11217 * opened to the cgroup directory in cgroupfs. The cpu argument
11218 * designates the cpu on which to monitor threads from that
11221 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
11224 if (flags & PERF_FLAG_FD_CLOEXEC)
11225 f_flags |= O_CLOEXEC;
11227 event_fd = get_unused_fd_flags(f_flags);
11231 if (group_fd != -1) {
11232 err = perf_fget_light(group_fd, &group);
11235 group_leader = group.file->private_data;
11236 if (flags & PERF_FLAG_FD_OUTPUT)
11237 output_event = group_leader;
11238 if (flags & PERF_FLAG_FD_NO_GROUP)
11239 group_leader = NULL;
11242 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
11243 task = find_lively_task_by_vpid(pid);
11244 if (IS_ERR(task)) {
11245 err = PTR_ERR(task);
11250 if (task && group_leader &&
11251 group_leader->attr.inherit != attr.inherit) {
11257 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
11262 * Reuse ptrace permission checks for now.
11264 * We must hold cred_guard_mutex across this and any potential
11265 * perf_install_in_context() call for this new event to
11266 * serialize against exec() altering our credentials (and the
11267 * perf_event_exit_task() that could imply).
11270 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
11274 if (flags & PERF_FLAG_PID_CGROUP)
11277 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11278 NULL, NULL, cgroup_fd);
11279 if (IS_ERR(event)) {
11280 err = PTR_ERR(event);
11284 if (is_sampling_event(event)) {
11285 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11292 * Special case software events and allow them to be part of
11293 * any hardware group.
11297 if (attr.use_clockid) {
11298 err = perf_event_set_clock(event, attr.clockid);
11303 if (pmu->task_ctx_nr == perf_sw_context)
11304 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11306 if (group_leader) {
11307 if (is_software_event(event) &&
11308 !in_software_context(group_leader)) {
11310 * If the event is a sw event, but the group_leader
11311 * is on hw context.
11313 * Allow the addition of software events to hw
11314 * groups, this is safe because software events
11315 * never fail to schedule.
11317 pmu = group_leader->ctx->pmu;
11318 } else if (!is_software_event(event) &&
11319 is_software_event(group_leader) &&
11320 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11322 * In case the group is a pure software group, and we
11323 * try to add a hardware event, move the whole group to
11324 * the hardware context.
11331 * Get the target context (task or percpu):
11333 ctx = find_get_context(pmu, task, event);
11335 err = PTR_ERR(ctx);
11340 * Look up the group leader (we will attach this event to it):
11342 if (group_leader) {
11346 * Do not allow a recursive hierarchy (this new sibling
11347 * becoming part of another group-sibling):
11349 if (group_leader->group_leader != group_leader)
11352 /* All events in a group should have the same clock */
11353 if (group_leader->clock != event->clock)
11357 * Make sure we're both events for the same CPU;
11358 * grouping events for different CPUs is broken; since
11359 * you can never concurrently schedule them anyhow.
11361 if (group_leader->cpu != event->cpu)
11365 * Make sure we're both on the same task, or both
11368 if (group_leader->ctx->task != ctx->task)
11372 * Do not allow to attach to a group in a different task
11373 * or CPU context. If we're moving SW events, we'll fix
11374 * this up later, so allow that.
11376 if (!move_group && group_leader->ctx != ctx)
11380 * Only a group leader can be exclusive or pinned
11382 if (attr.exclusive || attr.pinned)
11386 if (output_event) {
11387 err = perf_event_set_output(event, output_event);
11392 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11394 if (IS_ERR(event_file)) {
11395 err = PTR_ERR(event_file);
11401 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11403 if (gctx->task == TASK_TOMBSTONE) {
11409 * Check if we raced against another sys_perf_event_open() call
11410 * moving the software group underneath us.
11412 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11414 * If someone moved the group out from under us, check
11415 * if this new event wound up on the same ctx, if so
11416 * its the regular !move_group case, otherwise fail.
11422 perf_event_ctx_unlock(group_leader, gctx);
11428 * Failure to create exclusive events returns -EBUSY.
11431 if (!exclusive_event_installable(group_leader, ctx))
11434 for_each_sibling_event(sibling, group_leader) {
11435 if (!exclusive_event_installable(sibling, ctx))
11439 mutex_lock(&ctx->mutex);
11442 if (ctx->task == TASK_TOMBSTONE) {
11447 if (!perf_event_validate_size(event)) {
11454 * Check if the @cpu we're creating an event for is online.
11456 * We use the perf_cpu_context::ctx::mutex to serialize against
11457 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11459 struct perf_cpu_context *cpuctx =
11460 container_of(ctx, struct perf_cpu_context, ctx);
11462 if (!cpuctx->online) {
11468 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
11474 * Must be under the same ctx::mutex as perf_install_in_context(),
11475 * because we need to serialize with concurrent event creation.
11477 if (!exclusive_event_installable(event, ctx)) {
11482 WARN_ON_ONCE(ctx->parent_ctx);
11485 * This is the point on no return; we cannot fail hereafter. This is
11486 * where we start modifying current state.
11491 * See perf_event_ctx_lock() for comments on the details
11492 * of swizzling perf_event::ctx.
11494 perf_remove_from_context(group_leader, 0);
11497 for_each_sibling_event(sibling, group_leader) {
11498 perf_remove_from_context(sibling, 0);
11503 * Wait for everybody to stop referencing the events through
11504 * the old lists, before installing it on new lists.
11509 * Install the group siblings before the group leader.
11511 * Because a group leader will try and install the entire group
11512 * (through the sibling list, which is still in-tact), we can
11513 * end up with siblings installed in the wrong context.
11515 * By installing siblings first we NO-OP because they're not
11516 * reachable through the group lists.
11518 for_each_sibling_event(sibling, group_leader) {
11519 perf_event__state_init(sibling);
11520 perf_install_in_context(ctx, sibling, sibling->cpu);
11525 * Removing from the context ends up with disabled
11526 * event. What we want here is event in the initial
11527 * startup state, ready to be add into new context.
11529 perf_event__state_init(group_leader);
11530 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11535 * Precalculate sample_data sizes; do while holding ctx::mutex such
11536 * that we're serialized against further additions and before
11537 * perf_install_in_context() which is the point the event is active and
11538 * can use these values.
11540 perf_event__header_size(event);
11541 perf_event__id_header_size(event);
11543 event->owner = current;
11545 perf_install_in_context(ctx, event, event->cpu);
11546 perf_unpin_context(ctx);
11549 perf_event_ctx_unlock(group_leader, gctx);
11550 mutex_unlock(&ctx->mutex);
11553 mutex_unlock(&task->signal->cred_guard_mutex);
11554 put_task_struct(task);
11557 mutex_lock(¤t->perf_event_mutex);
11558 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11559 mutex_unlock(¤t->perf_event_mutex);
11562 * Drop the reference on the group_event after placing the
11563 * new event on the sibling_list. This ensures destruction
11564 * of the group leader will find the pointer to itself in
11565 * perf_group_detach().
11568 fd_install(event_fd, event_file);
11573 perf_event_ctx_unlock(group_leader, gctx);
11574 mutex_unlock(&ctx->mutex);
11578 perf_unpin_context(ctx);
11582 * If event_file is set, the fput() above will have called ->release()
11583 * and that will take care of freeing the event.
11589 mutex_unlock(&task->signal->cred_guard_mutex);
11592 put_task_struct(task);
11596 put_unused_fd(event_fd);
11601 * perf_event_create_kernel_counter
11603 * @attr: attributes of the counter to create
11604 * @cpu: cpu in which the counter is bound
11605 * @task: task to profile (NULL for percpu)
11607 struct perf_event *
11608 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11609 struct task_struct *task,
11610 perf_overflow_handler_t overflow_handler,
11613 struct perf_event_context *ctx;
11614 struct perf_event *event;
11618 * Grouping is not supported for kernel events, neither is 'AUX',
11619 * make sure the caller's intentions are adjusted.
11621 if (attr->aux_output)
11622 return ERR_PTR(-EINVAL);
11624 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11625 overflow_handler, context, -1);
11626 if (IS_ERR(event)) {
11627 err = PTR_ERR(event);
11631 /* Mark owner so we could distinguish it from user events. */
11632 event->owner = TASK_TOMBSTONE;
11635 * Get the target context (task or percpu):
11637 ctx = find_get_context(event->pmu, task, event);
11639 err = PTR_ERR(ctx);
11643 WARN_ON_ONCE(ctx->parent_ctx);
11644 mutex_lock(&ctx->mutex);
11645 if (ctx->task == TASK_TOMBSTONE) {
11652 * Check if the @cpu we're creating an event for is online.
11654 * We use the perf_cpu_context::ctx::mutex to serialize against
11655 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11657 struct perf_cpu_context *cpuctx =
11658 container_of(ctx, struct perf_cpu_context, ctx);
11659 if (!cpuctx->online) {
11665 if (!exclusive_event_installable(event, ctx)) {
11670 perf_install_in_context(ctx, event, event->cpu);
11671 perf_unpin_context(ctx);
11672 mutex_unlock(&ctx->mutex);
11677 mutex_unlock(&ctx->mutex);
11678 perf_unpin_context(ctx);
11683 return ERR_PTR(err);
11685 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11687 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11689 struct perf_event_context *src_ctx;
11690 struct perf_event_context *dst_ctx;
11691 struct perf_event *event, *tmp;
11694 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11695 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11698 * See perf_event_ctx_lock() for comments on the details
11699 * of swizzling perf_event::ctx.
11701 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11702 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11704 perf_remove_from_context(event, 0);
11705 unaccount_event_cpu(event, src_cpu);
11707 list_add(&event->migrate_entry, &events);
11711 * Wait for the events to quiesce before re-instating them.
11716 * Re-instate events in 2 passes.
11718 * Skip over group leaders and only install siblings on this first
11719 * pass, siblings will not get enabled without a leader, however a
11720 * leader will enable its siblings, even if those are still on the old
11723 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11724 if (event->group_leader == event)
11727 list_del(&event->migrate_entry);
11728 if (event->state >= PERF_EVENT_STATE_OFF)
11729 event->state = PERF_EVENT_STATE_INACTIVE;
11730 account_event_cpu(event, dst_cpu);
11731 perf_install_in_context(dst_ctx, event, dst_cpu);
11736 * Once all the siblings are setup properly, install the group leaders
11739 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11740 list_del(&event->migrate_entry);
11741 if (event->state >= PERF_EVENT_STATE_OFF)
11742 event->state = PERF_EVENT_STATE_INACTIVE;
11743 account_event_cpu(event, dst_cpu);
11744 perf_install_in_context(dst_ctx, event, dst_cpu);
11747 mutex_unlock(&dst_ctx->mutex);
11748 mutex_unlock(&src_ctx->mutex);
11750 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11752 static void sync_child_event(struct perf_event *child_event,
11753 struct task_struct *child)
11755 struct perf_event *parent_event = child_event->parent;
11758 if (child_event->attr.inherit_stat)
11759 perf_event_read_event(child_event, child);
11761 child_val = perf_event_count(child_event);
11764 * Add back the child's count to the parent's count:
11766 atomic64_add(child_val, &parent_event->child_count);
11767 atomic64_add(child_event->total_time_enabled,
11768 &parent_event->child_total_time_enabled);
11769 atomic64_add(child_event->total_time_running,
11770 &parent_event->child_total_time_running);
11774 perf_event_exit_event(struct perf_event *child_event,
11775 struct perf_event_context *child_ctx,
11776 struct task_struct *child)
11778 struct perf_event *parent_event = child_event->parent;
11781 * Do not destroy the 'original' grouping; because of the context
11782 * switch optimization the original events could've ended up in a
11783 * random child task.
11785 * If we were to destroy the original group, all group related
11786 * operations would cease to function properly after this random
11789 * Do destroy all inherited groups, we don't care about those
11790 * and being thorough is better.
11792 raw_spin_lock_irq(&child_ctx->lock);
11793 WARN_ON_ONCE(child_ctx->is_active);
11796 perf_group_detach(child_event);
11797 list_del_event(child_event, child_ctx);
11798 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11799 raw_spin_unlock_irq(&child_ctx->lock);
11802 * Parent events are governed by their filedesc, retain them.
11804 if (!parent_event) {
11805 perf_event_wakeup(child_event);
11809 * Child events can be cleaned up.
11812 sync_child_event(child_event, child);
11815 * Remove this event from the parent's list
11817 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11818 mutex_lock(&parent_event->child_mutex);
11819 list_del_init(&child_event->child_list);
11820 mutex_unlock(&parent_event->child_mutex);
11823 * Kick perf_poll() for is_event_hup().
11825 perf_event_wakeup(parent_event);
11826 free_event(child_event);
11827 put_event(parent_event);
11830 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11832 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11833 struct perf_event *child_event, *next;
11835 WARN_ON_ONCE(child != current);
11837 child_ctx = perf_pin_task_context(child, ctxn);
11842 * In order to reduce the amount of tricky in ctx tear-down, we hold
11843 * ctx::mutex over the entire thing. This serializes against almost
11844 * everything that wants to access the ctx.
11846 * The exception is sys_perf_event_open() /
11847 * perf_event_create_kernel_count() which does find_get_context()
11848 * without ctx::mutex (it cannot because of the move_group double mutex
11849 * lock thing). See the comments in perf_install_in_context().
11851 mutex_lock(&child_ctx->mutex);
11854 * In a single ctx::lock section, de-schedule the events and detach the
11855 * context from the task such that we cannot ever get it scheduled back
11858 raw_spin_lock_irq(&child_ctx->lock);
11859 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11862 * Now that the context is inactive, destroy the task <-> ctx relation
11863 * and mark the context dead.
11865 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11866 put_ctx(child_ctx); /* cannot be last */
11867 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11868 put_task_struct(current); /* cannot be last */
11870 clone_ctx = unclone_ctx(child_ctx);
11871 raw_spin_unlock_irq(&child_ctx->lock);
11874 put_ctx(clone_ctx);
11877 * Report the task dead after unscheduling the events so that we
11878 * won't get any samples after PERF_RECORD_EXIT. We can however still
11879 * get a few PERF_RECORD_READ events.
11881 perf_event_task(child, child_ctx, 0);
11883 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11884 perf_event_exit_event(child_event, child_ctx, child);
11886 mutex_unlock(&child_ctx->mutex);
11888 put_ctx(child_ctx);
11892 * When a child task exits, feed back event values to parent events.
11894 * Can be called with cred_guard_mutex held when called from
11895 * install_exec_creds().
11897 void perf_event_exit_task(struct task_struct *child)
11899 struct perf_event *event, *tmp;
11902 mutex_lock(&child->perf_event_mutex);
11903 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11905 list_del_init(&event->owner_entry);
11908 * Ensure the list deletion is visible before we clear
11909 * the owner, closes a race against perf_release() where
11910 * we need to serialize on the owner->perf_event_mutex.
11912 smp_store_release(&event->owner, NULL);
11914 mutex_unlock(&child->perf_event_mutex);
11916 for_each_task_context_nr(ctxn)
11917 perf_event_exit_task_context(child, ctxn);
11920 * The perf_event_exit_task_context calls perf_event_task
11921 * with child's task_ctx, which generates EXIT events for
11922 * child contexts and sets child->perf_event_ctxp[] to NULL.
11923 * At this point we need to send EXIT events to cpu contexts.
11925 perf_event_task(child, NULL, 0);
11928 static void perf_free_event(struct perf_event *event,
11929 struct perf_event_context *ctx)
11931 struct perf_event *parent = event->parent;
11933 if (WARN_ON_ONCE(!parent))
11936 mutex_lock(&parent->child_mutex);
11937 list_del_init(&event->child_list);
11938 mutex_unlock(&parent->child_mutex);
11942 raw_spin_lock_irq(&ctx->lock);
11943 perf_group_detach(event);
11944 list_del_event(event, ctx);
11945 raw_spin_unlock_irq(&ctx->lock);
11950 * Free a context as created by inheritance by perf_event_init_task() below,
11951 * used by fork() in case of fail.
11953 * Even though the task has never lived, the context and events have been
11954 * exposed through the child_list, so we must take care tearing it all down.
11956 void perf_event_free_task(struct task_struct *task)
11958 struct perf_event_context *ctx;
11959 struct perf_event *event, *tmp;
11962 for_each_task_context_nr(ctxn) {
11963 ctx = task->perf_event_ctxp[ctxn];
11967 mutex_lock(&ctx->mutex);
11968 raw_spin_lock_irq(&ctx->lock);
11970 * Destroy the task <-> ctx relation and mark the context dead.
11972 * This is important because even though the task hasn't been
11973 * exposed yet the context has been (through child_list).
11975 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11976 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11977 put_task_struct(task); /* cannot be last */
11978 raw_spin_unlock_irq(&ctx->lock);
11980 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11981 perf_free_event(event, ctx);
11983 mutex_unlock(&ctx->mutex);
11986 * perf_event_release_kernel() could've stolen some of our
11987 * child events and still have them on its free_list. In that
11988 * case we must wait for these events to have been freed (in
11989 * particular all their references to this task must've been
11992 * Without this copy_process() will unconditionally free this
11993 * task (irrespective of its reference count) and
11994 * _free_event()'s put_task_struct(event->hw.target) will be a
11997 * Wait for all events to drop their context reference.
11999 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12000 put_ctx(ctx); /* must be last */
12004 void perf_event_delayed_put(struct task_struct *task)
12008 for_each_task_context_nr(ctxn)
12009 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12012 struct file *perf_event_get(unsigned int fd)
12014 struct file *file = fget(fd);
12016 return ERR_PTR(-EBADF);
12018 if (file->f_op != &perf_fops) {
12020 return ERR_PTR(-EBADF);
12026 const struct perf_event *perf_get_event(struct file *file)
12028 if (file->f_op != &perf_fops)
12029 return ERR_PTR(-EINVAL);
12031 return file->private_data;
12034 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12037 return ERR_PTR(-EINVAL);
12039 return &event->attr;
12043 * Inherit an event from parent task to child task.
12046 * - valid pointer on success
12047 * - NULL for orphaned events
12048 * - IS_ERR() on error
12050 static struct perf_event *
12051 inherit_event(struct perf_event *parent_event,
12052 struct task_struct *parent,
12053 struct perf_event_context *parent_ctx,
12054 struct task_struct *child,
12055 struct perf_event *group_leader,
12056 struct perf_event_context *child_ctx)
12058 enum perf_event_state parent_state = parent_event->state;
12059 struct perf_event *child_event;
12060 unsigned long flags;
12063 * Instead of creating recursive hierarchies of events,
12064 * we link inherited events back to the original parent,
12065 * which has a filp for sure, which we use as the reference
12068 if (parent_event->parent)
12069 parent_event = parent_event->parent;
12071 child_event = perf_event_alloc(&parent_event->attr,
12074 group_leader, parent_event,
12076 if (IS_ERR(child_event))
12077 return child_event;
12080 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12081 !child_ctx->task_ctx_data) {
12082 struct pmu *pmu = child_event->pmu;
12084 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
12086 if (!child_ctx->task_ctx_data) {
12087 free_event(child_event);
12088 return ERR_PTR(-ENOMEM);
12093 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12094 * must be under the same lock in order to serialize against
12095 * perf_event_release_kernel(), such that either we must observe
12096 * is_orphaned_event() or they will observe us on the child_list.
12098 mutex_lock(&parent_event->child_mutex);
12099 if (is_orphaned_event(parent_event) ||
12100 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12101 mutex_unlock(&parent_event->child_mutex);
12102 /* task_ctx_data is freed with child_ctx */
12103 free_event(child_event);
12107 get_ctx(child_ctx);
12110 * Make the child state follow the state of the parent event,
12111 * not its attr.disabled bit. We hold the parent's mutex,
12112 * so we won't race with perf_event_{en, dis}able_family.
12114 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12115 child_event->state = PERF_EVENT_STATE_INACTIVE;
12117 child_event->state = PERF_EVENT_STATE_OFF;
12119 if (parent_event->attr.freq) {
12120 u64 sample_period = parent_event->hw.sample_period;
12121 struct hw_perf_event *hwc = &child_event->hw;
12123 hwc->sample_period = sample_period;
12124 hwc->last_period = sample_period;
12126 local64_set(&hwc->period_left, sample_period);
12129 child_event->ctx = child_ctx;
12130 child_event->overflow_handler = parent_event->overflow_handler;
12131 child_event->overflow_handler_context
12132 = parent_event->overflow_handler_context;
12135 * Precalculate sample_data sizes
12137 perf_event__header_size(child_event);
12138 perf_event__id_header_size(child_event);
12141 * Link it up in the child's context:
12143 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12144 add_event_to_ctx(child_event, child_ctx);
12145 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12148 * Link this into the parent event's child list
12150 list_add_tail(&child_event->child_list, &parent_event->child_list);
12151 mutex_unlock(&parent_event->child_mutex);
12153 return child_event;
12157 * Inherits an event group.
12159 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12160 * This matches with perf_event_release_kernel() removing all child events.
12166 static int inherit_group(struct perf_event *parent_event,
12167 struct task_struct *parent,
12168 struct perf_event_context *parent_ctx,
12169 struct task_struct *child,
12170 struct perf_event_context *child_ctx)
12172 struct perf_event *leader;
12173 struct perf_event *sub;
12174 struct perf_event *child_ctr;
12176 leader = inherit_event(parent_event, parent, parent_ctx,
12177 child, NULL, child_ctx);
12178 if (IS_ERR(leader))
12179 return PTR_ERR(leader);
12181 * @leader can be NULL here because of is_orphaned_event(). In this
12182 * case inherit_event() will create individual events, similar to what
12183 * perf_group_detach() would do anyway.
12185 for_each_sibling_event(sub, parent_event) {
12186 child_ctr = inherit_event(sub, parent, parent_ctx,
12187 child, leader, child_ctx);
12188 if (IS_ERR(child_ctr))
12189 return PTR_ERR(child_ctr);
12191 if (sub->aux_event == parent_event && child_ctr &&
12192 !perf_get_aux_event(child_ctr, leader))
12199 * Creates the child task context and tries to inherit the event-group.
12201 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12202 * inherited_all set when we 'fail' to inherit an orphaned event; this is
12203 * consistent with perf_event_release_kernel() removing all child events.
12210 inherit_task_group(struct perf_event *event, struct task_struct *parent,
12211 struct perf_event_context *parent_ctx,
12212 struct task_struct *child, int ctxn,
12213 int *inherited_all)
12216 struct perf_event_context *child_ctx;
12218 if (!event->attr.inherit) {
12219 *inherited_all = 0;
12223 child_ctx = child->perf_event_ctxp[ctxn];
12226 * This is executed from the parent task context, so
12227 * inherit events that have been marked for cloning.
12228 * First allocate and initialize a context for the
12231 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
12235 child->perf_event_ctxp[ctxn] = child_ctx;
12238 ret = inherit_group(event, parent, parent_ctx,
12242 *inherited_all = 0;
12248 * Initialize the perf_event context in task_struct
12250 static int perf_event_init_context(struct task_struct *child, int ctxn)
12252 struct perf_event_context *child_ctx, *parent_ctx;
12253 struct perf_event_context *cloned_ctx;
12254 struct perf_event *event;
12255 struct task_struct *parent = current;
12256 int inherited_all = 1;
12257 unsigned long flags;
12260 if (likely(!parent->perf_event_ctxp[ctxn]))
12264 * If the parent's context is a clone, pin it so it won't get
12265 * swapped under us.
12267 parent_ctx = perf_pin_task_context(parent, ctxn);
12272 * No need to check if parent_ctx != NULL here; since we saw
12273 * it non-NULL earlier, the only reason for it to become NULL
12274 * is if we exit, and since we're currently in the middle of
12275 * a fork we can't be exiting at the same time.
12279 * Lock the parent list. No need to lock the child - not PID
12280 * hashed yet and not running, so nobody can access it.
12282 mutex_lock(&parent_ctx->mutex);
12285 * We dont have to disable NMIs - we are only looking at
12286 * the list, not manipulating it:
12288 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12289 ret = inherit_task_group(event, parent, parent_ctx,
12290 child, ctxn, &inherited_all);
12296 * We can't hold ctx->lock when iterating the ->flexible_group list due
12297 * to allocations, but we need to prevent rotation because
12298 * rotate_ctx() will change the list from interrupt context.
12300 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12301 parent_ctx->rotate_disable = 1;
12302 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12304 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12305 ret = inherit_task_group(event, parent, parent_ctx,
12306 child, ctxn, &inherited_all);
12311 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12312 parent_ctx->rotate_disable = 0;
12314 child_ctx = child->perf_event_ctxp[ctxn];
12316 if (child_ctx && inherited_all) {
12318 * Mark the child context as a clone of the parent
12319 * context, or of whatever the parent is a clone of.
12321 * Note that if the parent is a clone, the holding of
12322 * parent_ctx->lock avoids it from being uncloned.
12324 cloned_ctx = parent_ctx->parent_ctx;
12326 child_ctx->parent_ctx = cloned_ctx;
12327 child_ctx->parent_gen = parent_ctx->parent_gen;
12329 child_ctx->parent_ctx = parent_ctx;
12330 child_ctx->parent_gen = parent_ctx->generation;
12332 get_ctx(child_ctx->parent_ctx);
12335 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12337 mutex_unlock(&parent_ctx->mutex);
12339 perf_unpin_context(parent_ctx);
12340 put_ctx(parent_ctx);
12346 * Initialize the perf_event context in task_struct
12348 int perf_event_init_task(struct task_struct *child)
12352 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12353 mutex_init(&child->perf_event_mutex);
12354 INIT_LIST_HEAD(&child->perf_event_list);
12356 for_each_task_context_nr(ctxn) {
12357 ret = perf_event_init_context(child, ctxn);
12359 perf_event_free_task(child);
12367 static void __init perf_event_init_all_cpus(void)
12369 struct swevent_htable *swhash;
12372 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12374 for_each_possible_cpu(cpu) {
12375 swhash = &per_cpu(swevent_htable, cpu);
12376 mutex_init(&swhash->hlist_mutex);
12377 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12379 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12380 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12382 #ifdef CONFIG_CGROUP_PERF
12383 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12385 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12389 static void perf_swevent_init_cpu(unsigned int cpu)
12391 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12393 mutex_lock(&swhash->hlist_mutex);
12394 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12395 struct swevent_hlist *hlist;
12397 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12399 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12401 mutex_unlock(&swhash->hlist_mutex);
12404 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12405 static void __perf_event_exit_context(void *__info)
12407 struct perf_event_context *ctx = __info;
12408 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12409 struct perf_event *event;
12411 raw_spin_lock(&ctx->lock);
12412 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12413 list_for_each_entry(event, &ctx->event_list, event_entry)
12414 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12415 raw_spin_unlock(&ctx->lock);
12418 static void perf_event_exit_cpu_context(int cpu)
12420 struct perf_cpu_context *cpuctx;
12421 struct perf_event_context *ctx;
12424 mutex_lock(&pmus_lock);
12425 list_for_each_entry(pmu, &pmus, entry) {
12426 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12427 ctx = &cpuctx->ctx;
12429 mutex_lock(&ctx->mutex);
12430 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12431 cpuctx->online = 0;
12432 mutex_unlock(&ctx->mutex);
12434 cpumask_clear_cpu(cpu, perf_online_mask);
12435 mutex_unlock(&pmus_lock);
12439 static void perf_event_exit_cpu_context(int cpu) { }
12443 int perf_event_init_cpu(unsigned int cpu)
12445 struct perf_cpu_context *cpuctx;
12446 struct perf_event_context *ctx;
12449 perf_swevent_init_cpu(cpu);
12451 mutex_lock(&pmus_lock);
12452 cpumask_set_cpu(cpu, perf_online_mask);
12453 list_for_each_entry(pmu, &pmus, entry) {
12454 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12455 ctx = &cpuctx->ctx;
12457 mutex_lock(&ctx->mutex);
12458 cpuctx->online = 1;
12459 mutex_unlock(&ctx->mutex);
12461 mutex_unlock(&pmus_lock);
12466 int perf_event_exit_cpu(unsigned int cpu)
12468 perf_event_exit_cpu_context(cpu);
12473 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12477 for_each_online_cpu(cpu)
12478 perf_event_exit_cpu(cpu);
12484 * Run the perf reboot notifier at the very last possible moment so that
12485 * the generic watchdog code runs as long as possible.
12487 static struct notifier_block perf_reboot_notifier = {
12488 .notifier_call = perf_reboot,
12489 .priority = INT_MIN,
12492 void __init perf_event_init(void)
12496 idr_init(&pmu_idr);
12498 perf_event_init_all_cpus();
12499 init_srcu_struct(&pmus_srcu);
12500 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12501 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12502 perf_pmu_register(&perf_task_clock, NULL, -1);
12503 perf_tp_register();
12504 perf_event_init_cpu(smp_processor_id());
12505 register_reboot_notifier(&perf_reboot_notifier);
12507 ret = init_hw_breakpoint();
12508 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12511 * Build time assertion that we keep the data_head at the intended
12512 * location. IOW, validation we got the __reserved[] size right.
12514 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12518 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12521 struct perf_pmu_events_attr *pmu_attr =
12522 container_of(attr, struct perf_pmu_events_attr, attr);
12524 if (pmu_attr->event_str)
12525 return sprintf(page, "%s\n", pmu_attr->event_str);
12529 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12531 static int __init perf_event_sysfs_init(void)
12536 mutex_lock(&pmus_lock);
12538 ret = bus_register(&pmu_bus);
12542 list_for_each_entry(pmu, &pmus, entry) {
12543 if (!pmu->name || pmu->type < 0)
12546 ret = pmu_dev_alloc(pmu);
12547 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12549 pmu_bus_running = 1;
12553 mutex_unlock(&pmus_lock);
12557 device_initcall(perf_event_sysfs_init);
12559 #ifdef CONFIG_CGROUP_PERF
12560 static struct cgroup_subsys_state *
12561 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12563 struct perf_cgroup *jc;
12565 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12567 return ERR_PTR(-ENOMEM);
12569 jc->info = alloc_percpu(struct perf_cgroup_info);
12572 return ERR_PTR(-ENOMEM);
12578 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12580 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12582 free_percpu(jc->info);
12586 static int __perf_cgroup_move(void *info)
12588 struct task_struct *task = info;
12590 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12595 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12597 struct task_struct *task;
12598 struct cgroup_subsys_state *css;
12600 cgroup_taskset_for_each(task, css, tset)
12601 task_function_call(task, __perf_cgroup_move, task);
12604 struct cgroup_subsys perf_event_cgrp_subsys = {
12605 .css_alloc = perf_cgroup_css_alloc,
12606 .css_free = perf_cgroup_css_free,
12607 .attach = perf_cgroup_attach,
12609 * Implicitly enable on dfl hierarchy so that perf events can
12610 * always be filtered by cgroup2 path as long as perf_event
12611 * controller is not mounted on a legacy hierarchy.
12613 .implicit_on_dfl = true,
12616 #endif /* CONFIG_CGROUP_PERF */