1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/rculist.h>
32 #include <linux/uaccess.h>
33 #include <linux/syscalls.h>
34 #include <linux/anon_inodes.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/cgroup.h>
37 #include <linux/perf_event.h>
38 #include <linux/trace_events.h>
39 #include <linux/hw_breakpoint.h>
40 #include <linux/mm_types.h>
41 #include <linux/module.h>
42 #include <linux/mman.h>
43 #include <linux/compat.h>
44 #include <linux/bpf.h>
45 #include <linux/filter.h>
46 #include <linux/namei.h>
47 #include <linux/parser.h>
48 #include <linux/sched/clock.h>
49 #include <linux/sched/mm.h>
50 #include <linux/proc_ns.h>
51 #include <linux/mount.h>
55 #include <asm/irq_regs.h>
57 typedef int (*remote_function_f)(void *);
59 struct remote_function_call {
60 struct task_struct *p;
61 remote_function_f func;
66 static void remote_function(void *data)
68 struct remote_function_call *tfc = data;
69 struct task_struct *p = tfc->p;
73 if (task_cpu(p) != smp_processor_id())
77 * Now that we're on right CPU with IRQs disabled, we can test
78 * if we hit the right task without races.
81 tfc->ret = -ESRCH; /* No such (running) process */
86 tfc->ret = tfc->func(tfc->info);
90 * task_function_call - call a function on the cpu on which a task runs
91 * @p: the task to evaluate
92 * @func: the function to be called
93 * @info: the function call argument
95 * Calls the function @func when the task is currently running. This might
96 * be on the current CPU, which just calls the function directly
98 * returns: @func return value, or
99 * -ESRCH - when the process isn't running
100 * -EAGAIN - when the process moved away
103 task_function_call(struct task_struct *p, remote_function_f func, void *info)
105 struct remote_function_call data = {
114 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
117 } while (ret == -EAGAIN);
123 * cpu_function_call - call a function on the cpu
124 * @func: the function to be called
125 * @info: the function call argument
127 * Calls the function @func on the remote cpu.
129 * returns: @func return value or -ENXIO when the cpu is offline
131 static int cpu_function_call(int cpu, remote_function_f func, void *info)
133 struct remote_function_call data = {
137 .ret = -ENXIO, /* No such CPU */
140 smp_call_function_single(cpu, remote_function, &data, 1);
145 static inline struct perf_cpu_context *
146 __get_cpu_context(struct perf_event_context *ctx)
148 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
151 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
152 struct perf_event_context *ctx)
154 raw_spin_lock(&cpuctx->ctx.lock);
156 raw_spin_lock(&ctx->lock);
159 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
160 struct perf_event_context *ctx)
163 raw_spin_unlock(&ctx->lock);
164 raw_spin_unlock(&cpuctx->ctx.lock);
167 #define TASK_TOMBSTONE ((void *)-1L)
169 static bool is_kernel_event(struct perf_event *event)
171 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
175 * On task ctx scheduling...
177 * When !ctx->nr_events a task context will not be scheduled. This means
178 * we can disable the scheduler hooks (for performance) without leaving
179 * pending task ctx state.
181 * This however results in two special cases:
183 * - removing the last event from a task ctx; this is relatively straight
184 * forward and is done in __perf_remove_from_context.
186 * - adding the first event to a task ctx; this is tricky because we cannot
187 * rely on ctx->is_active and therefore cannot use event_function_call().
188 * See perf_install_in_context().
190 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
193 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
194 struct perf_event_context *, void *);
196 struct event_function_struct {
197 struct perf_event *event;
202 static int event_function(void *info)
204 struct event_function_struct *efs = info;
205 struct perf_event *event = efs->event;
206 struct perf_event_context *ctx = event->ctx;
207 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
208 struct perf_event_context *task_ctx = cpuctx->task_ctx;
211 lockdep_assert_irqs_disabled();
213 perf_ctx_lock(cpuctx, task_ctx);
215 * Since we do the IPI call without holding ctx->lock things can have
216 * changed, double check we hit the task we set out to hit.
219 if (ctx->task != current) {
225 * We only use event_function_call() on established contexts,
226 * and event_function() is only ever called when active (or
227 * rather, we'll have bailed in task_function_call() or the
228 * above ctx->task != current test), therefore we must have
229 * ctx->is_active here.
231 WARN_ON_ONCE(!ctx->is_active);
233 * And since we have ctx->is_active, cpuctx->task_ctx must
236 WARN_ON_ONCE(task_ctx != ctx);
238 WARN_ON_ONCE(&cpuctx->ctx != ctx);
241 efs->func(event, cpuctx, ctx, efs->data);
243 perf_ctx_unlock(cpuctx, task_ctx);
248 static void event_function_call(struct perf_event *event, event_f func, void *data)
250 struct perf_event_context *ctx = event->ctx;
251 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
252 struct event_function_struct efs = {
258 if (!event->parent) {
260 * If this is a !child event, we must hold ctx::mutex to
261 * stabilize the the event->ctx relation. See
262 * perf_event_ctx_lock().
264 lockdep_assert_held(&ctx->mutex);
268 cpu_function_call(event->cpu, event_function, &efs);
272 if (task == TASK_TOMBSTONE)
276 if (!task_function_call(task, event_function, &efs))
279 raw_spin_lock_irq(&ctx->lock);
281 * Reload the task pointer, it might have been changed by
282 * a concurrent perf_event_context_sched_out().
285 if (task == TASK_TOMBSTONE) {
286 raw_spin_unlock_irq(&ctx->lock);
289 if (ctx->is_active) {
290 raw_spin_unlock_irq(&ctx->lock);
293 func(event, NULL, ctx, data);
294 raw_spin_unlock_irq(&ctx->lock);
298 * Similar to event_function_call() + event_function(), but hard assumes IRQs
299 * are already disabled and we're on the right CPU.
301 static void event_function_local(struct perf_event *event, event_f func, void *data)
303 struct perf_event_context *ctx = event->ctx;
304 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
305 struct task_struct *task = READ_ONCE(ctx->task);
306 struct perf_event_context *task_ctx = NULL;
308 lockdep_assert_irqs_disabled();
311 if (task == TASK_TOMBSTONE)
317 perf_ctx_lock(cpuctx, task_ctx);
320 if (task == TASK_TOMBSTONE)
325 * We must be either inactive or active and the right task,
326 * otherwise we're screwed, since we cannot IPI to somewhere
329 if (ctx->is_active) {
330 if (WARN_ON_ONCE(task != current))
333 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
337 WARN_ON_ONCE(&cpuctx->ctx != ctx);
340 func(event, cpuctx, ctx, data);
342 perf_ctx_unlock(cpuctx, task_ctx);
345 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
346 PERF_FLAG_FD_OUTPUT |\
347 PERF_FLAG_PID_CGROUP |\
348 PERF_FLAG_FD_CLOEXEC)
351 * branch priv levels that need permission checks
353 #define PERF_SAMPLE_BRANCH_PERM_PLM \
354 (PERF_SAMPLE_BRANCH_KERNEL |\
355 PERF_SAMPLE_BRANCH_HV)
358 EVENT_FLEXIBLE = 0x1,
361 /* see ctx_resched() for details */
363 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
367 * perf_sched_events : >0 events exist
368 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
371 static void perf_sched_delayed(struct work_struct *work);
372 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
373 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
374 static DEFINE_MUTEX(perf_sched_mutex);
375 static atomic_t perf_sched_count;
377 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
378 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
379 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
381 static atomic_t nr_mmap_events __read_mostly;
382 static atomic_t nr_comm_events __read_mostly;
383 static atomic_t nr_namespaces_events __read_mostly;
384 static atomic_t nr_task_events __read_mostly;
385 static atomic_t nr_freq_events __read_mostly;
386 static atomic_t nr_switch_events __read_mostly;
387 static atomic_t nr_ksymbol_events __read_mostly;
388 static atomic_t nr_bpf_events __read_mostly;
390 static LIST_HEAD(pmus);
391 static DEFINE_MUTEX(pmus_lock);
392 static struct srcu_struct pmus_srcu;
393 static cpumask_var_t perf_online_mask;
396 * perf event paranoia level:
397 * -1 - not paranoid at all
398 * 0 - disallow raw tracepoint access for unpriv
399 * 1 - disallow cpu events for unpriv
400 * 2 - disallow kernel profiling for unpriv
402 int sysctl_perf_event_paranoid __read_mostly = 2;
404 /* Minimum for 512 kiB + 1 user control page */
405 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
408 * max perf event sample rate
410 #define DEFAULT_MAX_SAMPLE_RATE 100000
411 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
412 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
414 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
416 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
417 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
419 static int perf_sample_allowed_ns __read_mostly =
420 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
422 static void update_perf_cpu_limits(void)
424 u64 tmp = perf_sample_period_ns;
426 tmp *= sysctl_perf_cpu_time_max_percent;
427 tmp = div_u64(tmp, 100);
431 WRITE_ONCE(perf_sample_allowed_ns, tmp);
434 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
436 int perf_proc_update_handler(struct ctl_table *table, int write,
437 void __user *buffer, size_t *lenp,
441 int perf_cpu = sysctl_perf_cpu_time_max_percent;
443 * If throttling is disabled don't allow the write:
445 if (write && (perf_cpu == 100 || perf_cpu == 0))
448 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
452 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
453 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
454 update_perf_cpu_limits();
459 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
461 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
462 void __user *buffer, size_t *lenp,
465 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
470 if (sysctl_perf_cpu_time_max_percent == 100 ||
471 sysctl_perf_cpu_time_max_percent == 0) {
473 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
474 WRITE_ONCE(perf_sample_allowed_ns, 0);
476 update_perf_cpu_limits();
483 * perf samples are done in some very critical code paths (NMIs).
484 * If they take too much CPU time, the system can lock up and not
485 * get any real work done. This will drop the sample rate when
486 * we detect that events are taking too long.
488 #define NR_ACCUMULATED_SAMPLES 128
489 static DEFINE_PER_CPU(u64, running_sample_length);
491 static u64 __report_avg;
492 static u64 __report_allowed;
494 static void perf_duration_warn(struct irq_work *w)
496 printk_ratelimited(KERN_INFO
497 "perf: interrupt took too long (%lld > %lld), lowering "
498 "kernel.perf_event_max_sample_rate to %d\n",
499 __report_avg, __report_allowed,
500 sysctl_perf_event_sample_rate);
503 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
505 void perf_sample_event_took(u64 sample_len_ns)
507 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
515 /* Decay the counter by 1 average sample. */
516 running_len = __this_cpu_read(running_sample_length);
517 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
518 running_len += sample_len_ns;
519 __this_cpu_write(running_sample_length, running_len);
522 * Note: this will be biased artifically low until we have
523 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
524 * from having to maintain a count.
526 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
527 if (avg_len <= max_len)
530 __report_avg = avg_len;
531 __report_allowed = max_len;
534 * Compute a throttle threshold 25% below the current duration.
536 avg_len += avg_len / 4;
537 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
543 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
544 WRITE_ONCE(max_samples_per_tick, max);
546 sysctl_perf_event_sample_rate = max * HZ;
547 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
549 if (!irq_work_queue(&perf_duration_work)) {
550 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
551 "kernel.perf_event_max_sample_rate to %d\n",
552 __report_avg, __report_allowed,
553 sysctl_perf_event_sample_rate);
557 static atomic64_t perf_event_id;
559 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
560 enum event_type_t event_type);
562 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
563 enum event_type_t event_type,
564 struct task_struct *task);
566 static void update_context_time(struct perf_event_context *ctx);
567 static u64 perf_event_time(struct perf_event *event);
569 void __weak perf_event_print_debug(void) { }
571 extern __weak const char *perf_pmu_name(void)
576 static inline u64 perf_clock(void)
578 return local_clock();
581 static inline u64 perf_event_clock(struct perf_event *event)
583 return event->clock();
587 * State based event timekeeping...
589 * The basic idea is to use event->state to determine which (if any) time
590 * fields to increment with the current delta. This means we only need to
591 * update timestamps when we change state or when they are explicitly requested
594 * Event groups make things a little more complicated, but not terribly so. The
595 * rules for a group are that if the group leader is OFF the entire group is
596 * OFF, irrespecive of what the group member states are. This results in
597 * __perf_effective_state().
599 * A futher ramification is that when a group leader flips between OFF and
600 * !OFF, we need to update all group member times.
603 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
604 * need to make sure the relevant context time is updated before we try and
605 * update our timestamps.
608 static __always_inline enum perf_event_state
609 __perf_effective_state(struct perf_event *event)
611 struct perf_event *leader = event->group_leader;
613 if (leader->state <= PERF_EVENT_STATE_OFF)
614 return leader->state;
619 static __always_inline void
620 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
622 enum perf_event_state state = __perf_effective_state(event);
623 u64 delta = now - event->tstamp;
625 *enabled = event->total_time_enabled;
626 if (state >= PERF_EVENT_STATE_INACTIVE)
629 *running = event->total_time_running;
630 if (state >= PERF_EVENT_STATE_ACTIVE)
634 static void perf_event_update_time(struct perf_event *event)
636 u64 now = perf_event_time(event);
638 __perf_update_times(event, now, &event->total_time_enabled,
639 &event->total_time_running);
643 static void perf_event_update_sibling_time(struct perf_event *leader)
645 struct perf_event *sibling;
647 for_each_sibling_event(sibling, leader)
648 perf_event_update_time(sibling);
652 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
654 if (event->state == state)
657 perf_event_update_time(event);
659 * If a group leader gets enabled/disabled all its siblings
662 if ((event->state < 0) ^ (state < 0))
663 perf_event_update_sibling_time(event);
665 WRITE_ONCE(event->state, state);
668 #ifdef CONFIG_CGROUP_PERF
671 perf_cgroup_match(struct perf_event *event)
673 struct perf_event_context *ctx = event->ctx;
674 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
676 /* @event doesn't care about cgroup */
680 /* wants specific cgroup scope but @cpuctx isn't associated with any */
685 * Cgroup scoping is recursive. An event enabled for a cgroup is
686 * also enabled for all its descendant cgroups. If @cpuctx's
687 * cgroup is a descendant of @event's (the test covers identity
688 * case), it's a match.
690 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
691 event->cgrp->css.cgroup);
694 static inline void perf_detach_cgroup(struct perf_event *event)
696 css_put(&event->cgrp->css);
700 static inline int is_cgroup_event(struct perf_event *event)
702 return event->cgrp != NULL;
705 static inline u64 perf_cgroup_event_time(struct perf_event *event)
707 struct perf_cgroup_info *t;
709 t = per_cpu_ptr(event->cgrp->info, event->cpu);
713 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
715 struct perf_cgroup_info *info;
720 info = this_cpu_ptr(cgrp->info);
722 info->time += now - info->timestamp;
723 info->timestamp = now;
726 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
728 struct perf_cgroup *cgrp = cpuctx->cgrp;
729 struct cgroup_subsys_state *css;
732 for (css = &cgrp->css; css; css = css->parent) {
733 cgrp = container_of(css, struct perf_cgroup, css);
734 __update_cgrp_time(cgrp);
739 static inline void update_cgrp_time_from_event(struct perf_event *event)
741 struct perf_cgroup *cgrp;
744 * ensure we access cgroup data only when needed and
745 * when we know the cgroup is pinned (css_get)
747 if (!is_cgroup_event(event))
750 cgrp = perf_cgroup_from_task(current, event->ctx);
752 * Do not update time when cgroup is not active
754 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
755 __update_cgrp_time(event->cgrp);
759 perf_cgroup_set_timestamp(struct task_struct *task,
760 struct perf_event_context *ctx)
762 struct perf_cgroup *cgrp;
763 struct perf_cgroup_info *info;
764 struct cgroup_subsys_state *css;
767 * ctx->lock held by caller
768 * ensure we do not access cgroup data
769 * unless we have the cgroup pinned (css_get)
771 if (!task || !ctx->nr_cgroups)
774 cgrp = perf_cgroup_from_task(task, ctx);
776 for (css = &cgrp->css; css; css = css->parent) {
777 cgrp = container_of(css, struct perf_cgroup, css);
778 info = this_cpu_ptr(cgrp->info);
779 info->timestamp = ctx->timestamp;
783 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
785 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
786 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
789 * reschedule events based on the cgroup constraint of task.
791 * mode SWOUT : schedule out everything
792 * mode SWIN : schedule in based on cgroup for next
794 static void perf_cgroup_switch(struct task_struct *task, int mode)
796 struct perf_cpu_context *cpuctx;
797 struct list_head *list;
801 * Disable interrupts and preemption to avoid this CPU's
802 * cgrp_cpuctx_entry to change under us.
804 local_irq_save(flags);
806 list = this_cpu_ptr(&cgrp_cpuctx_list);
807 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
808 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
810 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
811 perf_pmu_disable(cpuctx->ctx.pmu);
813 if (mode & PERF_CGROUP_SWOUT) {
814 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
816 * must not be done before ctxswout due
817 * to event_filter_match() in event_sched_out()
822 if (mode & PERF_CGROUP_SWIN) {
823 WARN_ON_ONCE(cpuctx->cgrp);
825 * set cgrp before ctxsw in to allow
826 * event_filter_match() to not have to pass
828 * we pass the cpuctx->ctx to perf_cgroup_from_task()
829 * because cgorup events are only per-cpu
831 cpuctx->cgrp = perf_cgroup_from_task(task,
833 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
835 perf_pmu_enable(cpuctx->ctx.pmu);
836 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
839 local_irq_restore(flags);
842 static inline void perf_cgroup_sched_out(struct task_struct *task,
843 struct task_struct *next)
845 struct perf_cgroup *cgrp1;
846 struct perf_cgroup *cgrp2 = NULL;
850 * we come here when we know perf_cgroup_events > 0
851 * we do not need to pass the ctx here because we know
852 * we are holding the rcu lock
854 cgrp1 = perf_cgroup_from_task(task, NULL);
855 cgrp2 = perf_cgroup_from_task(next, NULL);
858 * only schedule out current cgroup events if we know
859 * that we are switching to a different cgroup. Otherwise,
860 * do no touch the cgroup events.
863 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
868 static inline void perf_cgroup_sched_in(struct task_struct *prev,
869 struct task_struct *task)
871 struct perf_cgroup *cgrp1;
872 struct perf_cgroup *cgrp2 = NULL;
876 * we come here when we know perf_cgroup_events > 0
877 * we do not need to pass the ctx here because we know
878 * we are holding the rcu lock
880 cgrp1 = perf_cgroup_from_task(task, NULL);
881 cgrp2 = perf_cgroup_from_task(prev, NULL);
884 * only need to schedule in cgroup events if we are changing
885 * cgroup during ctxsw. Cgroup events were not scheduled
886 * out of ctxsw out if that was not the case.
889 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
894 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
895 struct perf_event_attr *attr,
896 struct perf_event *group_leader)
898 struct perf_cgroup *cgrp;
899 struct cgroup_subsys_state *css;
900 struct fd f = fdget(fd);
906 css = css_tryget_online_from_dir(f.file->f_path.dentry,
907 &perf_event_cgrp_subsys);
913 cgrp = container_of(css, struct perf_cgroup, css);
917 * all events in a group must monitor
918 * the same cgroup because a task belongs
919 * to only one perf cgroup at a time
921 if (group_leader && group_leader->cgrp != cgrp) {
922 perf_detach_cgroup(event);
931 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
933 struct perf_cgroup_info *t;
934 t = per_cpu_ptr(event->cgrp->info, event->cpu);
935 event->shadow_ctx_time = now - t->timestamp;
939 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
940 * cleared when last cgroup event is removed.
943 list_update_cgroup_event(struct perf_event *event,
944 struct perf_event_context *ctx, bool add)
946 struct perf_cpu_context *cpuctx;
947 struct list_head *cpuctx_entry;
949 if (!is_cgroup_event(event))
953 * Because cgroup events are always per-cpu events,
954 * this will always be called from the right CPU.
956 cpuctx = __get_cpu_context(ctx);
959 * Since setting cpuctx->cgrp is conditional on the current @cgrp
960 * matching the event's cgroup, we must do this for every new event,
961 * because if the first would mismatch, the second would not try again
962 * and we would leave cpuctx->cgrp unset.
964 if (add && !cpuctx->cgrp) {
965 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
967 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
971 if (add && ctx->nr_cgroups++)
973 else if (!add && --ctx->nr_cgroups)
976 /* no cgroup running */
980 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
982 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
984 list_del(cpuctx_entry);
987 #else /* !CONFIG_CGROUP_PERF */
990 perf_cgroup_match(struct perf_event *event)
995 static inline void perf_detach_cgroup(struct perf_event *event)
998 static inline int is_cgroup_event(struct perf_event *event)
1003 static inline void update_cgrp_time_from_event(struct perf_event *event)
1007 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1011 static inline void perf_cgroup_sched_out(struct task_struct *task,
1012 struct task_struct *next)
1016 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1017 struct task_struct *task)
1021 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1022 struct perf_event_attr *attr,
1023 struct perf_event *group_leader)
1029 perf_cgroup_set_timestamp(struct task_struct *task,
1030 struct perf_event_context *ctx)
1035 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1040 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1044 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1050 list_update_cgroup_event(struct perf_event *event,
1051 struct perf_event_context *ctx, bool add)
1058 * set default to be dependent on timer tick just
1059 * like original code
1061 #define PERF_CPU_HRTIMER (1000 / HZ)
1063 * function must be called with interrupts disabled
1065 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1067 struct perf_cpu_context *cpuctx;
1070 lockdep_assert_irqs_disabled();
1072 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1073 rotations = perf_rotate_context(cpuctx);
1075 raw_spin_lock(&cpuctx->hrtimer_lock);
1077 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1079 cpuctx->hrtimer_active = 0;
1080 raw_spin_unlock(&cpuctx->hrtimer_lock);
1082 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1085 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1087 struct hrtimer *timer = &cpuctx->hrtimer;
1088 struct pmu *pmu = cpuctx->ctx.pmu;
1091 /* no multiplexing needed for SW PMU */
1092 if (pmu->task_ctx_nr == perf_sw_context)
1096 * check default is sane, if not set then force to
1097 * default interval (1/tick)
1099 interval = pmu->hrtimer_interval_ms;
1101 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1103 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1105 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1106 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1107 timer->function = perf_mux_hrtimer_handler;
1110 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1112 struct hrtimer *timer = &cpuctx->hrtimer;
1113 struct pmu *pmu = cpuctx->ctx.pmu;
1114 unsigned long flags;
1116 /* not for SW PMU */
1117 if (pmu->task_ctx_nr == perf_sw_context)
1120 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1121 if (!cpuctx->hrtimer_active) {
1122 cpuctx->hrtimer_active = 1;
1123 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1124 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1126 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1131 void perf_pmu_disable(struct pmu *pmu)
1133 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1135 pmu->pmu_disable(pmu);
1138 void perf_pmu_enable(struct pmu *pmu)
1140 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1142 pmu->pmu_enable(pmu);
1145 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1148 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1149 * perf_event_task_tick() are fully serialized because they're strictly cpu
1150 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1151 * disabled, while perf_event_task_tick is called from IRQ context.
1153 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1155 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1157 lockdep_assert_irqs_disabled();
1159 WARN_ON(!list_empty(&ctx->active_ctx_list));
1161 list_add(&ctx->active_ctx_list, head);
1164 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1166 lockdep_assert_irqs_disabled();
1168 WARN_ON(list_empty(&ctx->active_ctx_list));
1170 list_del_init(&ctx->active_ctx_list);
1173 static void get_ctx(struct perf_event_context *ctx)
1175 refcount_inc(&ctx->refcount);
1178 static void free_ctx(struct rcu_head *head)
1180 struct perf_event_context *ctx;
1182 ctx = container_of(head, struct perf_event_context, rcu_head);
1183 kfree(ctx->task_ctx_data);
1187 static void put_ctx(struct perf_event_context *ctx)
1189 if (refcount_dec_and_test(&ctx->refcount)) {
1190 if (ctx->parent_ctx)
1191 put_ctx(ctx->parent_ctx);
1192 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1193 put_task_struct(ctx->task);
1194 call_rcu(&ctx->rcu_head, free_ctx);
1199 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1200 * perf_pmu_migrate_context() we need some magic.
1202 * Those places that change perf_event::ctx will hold both
1203 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1205 * Lock ordering is by mutex address. There are two other sites where
1206 * perf_event_context::mutex nests and those are:
1208 * - perf_event_exit_task_context() [ child , 0 ]
1209 * perf_event_exit_event()
1210 * put_event() [ parent, 1 ]
1212 * - perf_event_init_context() [ parent, 0 ]
1213 * inherit_task_group()
1216 * perf_event_alloc()
1218 * perf_try_init_event() [ child , 1 ]
1220 * While it appears there is an obvious deadlock here -- the parent and child
1221 * nesting levels are inverted between the two. This is in fact safe because
1222 * life-time rules separate them. That is an exiting task cannot fork, and a
1223 * spawning task cannot (yet) exit.
1225 * But remember that that these are parent<->child context relations, and
1226 * migration does not affect children, therefore these two orderings should not
1229 * The change in perf_event::ctx does not affect children (as claimed above)
1230 * because the sys_perf_event_open() case will install a new event and break
1231 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1232 * concerned with cpuctx and that doesn't have children.
1234 * The places that change perf_event::ctx will issue:
1236 * perf_remove_from_context();
1237 * synchronize_rcu();
1238 * perf_install_in_context();
1240 * to affect the change. The remove_from_context() + synchronize_rcu() should
1241 * quiesce the event, after which we can install it in the new location. This
1242 * means that only external vectors (perf_fops, prctl) can perturb the event
1243 * while in transit. Therefore all such accessors should also acquire
1244 * perf_event_context::mutex to serialize against this.
1246 * However; because event->ctx can change while we're waiting to acquire
1247 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1252 * task_struct::perf_event_mutex
1253 * perf_event_context::mutex
1254 * perf_event::child_mutex;
1255 * perf_event_context::lock
1256 * perf_event::mmap_mutex
1258 * perf_addr_filters_head::lock
1262 * cpuctx->mutex / perf_event_context::mutex
1264 static struct perf_event_context *
1265 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1267 struct perf_event_context *ctx;
1271 ctx = READ_ONCE(event->ctx);
1272 if (!refcount_inc_not_zero(&ctx->refcount)) {
1278 mutex_lock_nested(&ctx->mutex, nesting);
1279 if (event->ctx != ctx) {
1280 mutex_unlock(&ctx->mutex);
1288 static inline struct perf_event_context *
1289 perf_event_ctx_lock(struct perf_event *event)
1291 return perf_event_ctx_lock_nested(event, 0);
1294 static void perf_event_ctx_unlock(struct perf_event *event,
1295 struct perf_event_context *ctx)
1297 mutex_unlock(&ctx->mutex);
1302 * This must be done under the ctx->lock, such as to serialize against
1303 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1304 * calling scheduler related locks and ctx->lock nests inside those.
1306 static __must_check struct perf_event_context *
1307 unclone_ctx(struct perf_event_context *ctx)
1309 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1311 lockdep_assert_held(&ctx->lock);
1314 ctx->parent_ctx = NULL;
1320 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1325 * only top level events have the pid namespace they were created in
1328 event = event->parent;
1330 nr = __task_pid_nr_ns(p, type, event->ns);
1331 /* avoid -1 if it is idle thread or runs in another ns */
1332 if (!nr && !pid_alive(p))
1337 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1339 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1342 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1344 return perf_event_pid_type(event, p, PIDTYPE_PID);
1348 * If we inherit events we want to return the parent event id
1351 static u64 primary_event_id(struct perf_event *event)
1356 id = event->parent->id;
1362 * Get the perf_event_context for a task and lock it.
1364 * This has to cope with with the fact that until it is locked,
1365 * the context could get moved to another task.
1367 static struct perf_event_context *
1368 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1370 struct perf_event_context *ctx;
1374 * One of the few rules of preemptible RCU is that one cannot do
1375 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1376 * part of the read side critical section was irqs-enabled -- see
1377 * rcu_read_unlock_special().
1379 * Since ctx->lock nests under rq->lock we must ensure the entire read
1380 * side critical section has interrupts disabled.
1382 local_irq_save(*flags);
1384 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1387 * If this context is a clone of another, it might
1388 * get swapped for another underneath us by
1389 * perf_event_task_sched_out, though the
1390 * rcu_read_lock() protects us from any context
1391 * getting freed. Lock the context and check if it
1392 * got swapped before we could get the lock, and retry
1393 * if so. If we locked the right context, then it
1394 * can't get swapped on us any more.
1396 raw_spin_lock(&ctx->lock);
1397 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1398 raw_spin_unlock(&ctx->lock);
1400 local_irq_restore(*flags);
1404 if (ctx->task == TASK_TOMBSTONE ||
1405 !refcount_inc_not_zero(&ctx->refcount)) {
1406 raw_spin_unlock(&ctx->lock);
1409 WARN_ON_ONCE(ctx->task != task);
1414 local_irq_restore(*flags);
1419 * Get the context for a task and increment its pin_count so it
1420 * can't get swapped to another task. This also increments its
1421 * reference count so that the context can't get freed.
1423 static struct perf_event_context *
1424 perf_pin_task_context(struct task_struct *task, int ctxn)
1426 struct perf_event_context *ctx;
1427 unsigned long flags;
1429 ctx = perf_lock_task_context(task, ctxn, &flags);
1432 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1437 static void perf_unpin_context(struct perf_event_context *ctx)
1439 unsigned long flags;
1441 raw_spin_lock_irqsave(&ctx->lock, flags);
1443 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1447 * Update the record of the current time in a context.
1449 static void update_context_time(struct perf_event_context *ctx)
1451 u64 now = perf_clock();
1453 ctx->time += now - ctx->timestamp;
1454 ctx->timestamp = now;
1457 static u64 perf_event_time(struct perf_event *event)
1459 struct perf_event_context *ctx = event->ctx;
1461 if (is_cgroup_event(event))
1462 return perf_cgroup_event_time(event);
1464 return ctx ? ctx->time : 0;
1467 static enum event_type_t get_event_type(struct perf_event *event)
1469 struct perf_event_context *ctx = event->ctx;
1470 enum event_type_t event_type;
1472 lockdep_assert_held(&ctx->lock);
1475 * It's 'group type', really, because if our group leader is
1476 * pinned, so are we.
1478 if (event->group_leader != event)
1479 event = event->group_leader;
1481 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1483 event_type |= EVENT_CPU;
1489 * Helper function to initialize event group nodes.
1491 static void init_event_group(struct perf_event *event)
1493 RB_CLEAR_NODE(&event->group_node);
1494 event->group_index = 0;
1498 * Extract pinned or flexible groups from the context
1499 * based on event attrs bits.
1501 static struct perf_event_groups *
1502 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1504 if (event->attr.pinned)
1505 return &ctx->pinned_groups;
1507 return &ctx->flexible_groups;
1511 * Helper function to initializes perf_event_group trees.
1513 static void perf_event_groups_init(struct perf_event_groups *groups)
1515 groups->tree = RB_ROOT;
1520 * Compare function for event groups;
1522 * Implements complex key that first sorts by CPU and then by virtual index
1523 * which provides ordering when rotating groups for the same CPU.
1526 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1528 if (left->cpu < right->cpu)
1530 if (left->cpu > right->cpu)
1533 if (left->group_index < right->group_index)
1535 if (left->group_index > right->group_index)
1542 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1543 * key (see perf_event_groups_less). This places it last inside the CPU
1547 perf_event_groups_insert(struct perf_event_groups *groups,
1548 struct perf_event *event)
1550 struct perf_event *node_event;
1551 struct rb_node *parent;
1552 struct rb_node **node;
1554 event->group_index = ++groups->index;
1556 node = &groups->tree.rb_node;
1561 node_event = container_of(*node, struct perf_event, group_node);
1563 if (perf_event_groups_less(event, node_event))
1564 node = &parent->rb_left;
1566 node = &parent->rb_right;
1569 rb_link_node(&event->group_node, parent, node);
1570 rb_insert_color(&event->group_node, &groups->tree);
1574 * Helper function to insert event into the pinned or flexible groups.
1577 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1579 struct perf_event_groups *groups;
1581 groups = get_event_groups(event, ctx);
1582 perf_event_groups_insert(groups, event);
1586 * Delete a group from a tree.
1589 perf_event_groups_delete(struct perf_event_groups *groups,
1590 struct perf_event *event)
1592 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1593 RB_EMPTY_ROOT(&groups->tree));
1595 rb_erase(&event->group_node, &groups->tree);
1596 init_event_group(event);
1600 * Helper function to delete event from its groups.
1603 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1605 struct perf_event_groups *groups;
1607 groups = get_event_groups(event, ctx);
1608 perf_event_groups_delete(groups, event);
1612 * Get the leftmost event in the @cpu subtree.
1614 static struct perf_event *
1615 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1617 struct perf_event *node_event = NULL, *match = NULL;
1618 struct rb_node *node = groups->tree.rb_node;
1621 node_event = container_of(node, struct perf_event, group_node);
1623 if (cpu < node_event->cpu) {
1624 node = node->rb_left;
1625 } else if (cpu > node_event->cpu) {
1626 node = node->rb_right;
1629 node = node->rb_left;
1637 * Like rb_entry_next_safe() for the @cpu subtree.
1639 static struct perf_event *
1640 perf_event_groups_next(struct perf_event *event)
1642 struct perf_event *next;
1644 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1645 if (next && next->cpu == event->cpu)
1652 * Iterate through the whole groups tree.
1654 #define perf_event_groups_for_each(event, groups) \
1655 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1656 typeof(*event), group_node); event; \
1657 event = rb_entry_safe(rb_next(&event->group_node), \
1658 typeof(*event), group_node))
1661 * Add an event from the lists for its context.
1662 * Must be called with ctx->mutex and ctx->lock held.
1665 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1667 lockdep_assert_held(&ctx->lock);
1669 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1670 event->attach_state |= PERF_ATTACH_CONTEXT;
1672 event->tstamp = perf_event_time(event);
1675 * If we're a stand alone event or group leader, we go to the context
1676 * list, group events are kept attached to the group so that
1677 * perf_group_detach can, at all times, locate all siblings.
1679 if (event->group_leader == event) {
1680 event->group_caps = event->event_caps;
1681 add_event_to_groups(event, ctx);
1684 list_update_cgroup_event(event, ctx, true);
1686 list_add_rcu(&event->event_entry, &ctx->event_list);
1688 if (event->attr.inherit_stat)
1695 * Initialize event state based on the perf_event_attr::disabled.
1697 static inline void perf_event__state_init(struct perf_event *event)
1699 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1700 PERF_EVENT_STATE_INACTIVE;
1703 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1705 int entry = sizeof(u64); /* value */
1709 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1710 size += sizeof(u64);
1712 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1713 size += sizeof(u64);
1715 if (event->attr.read_format & PERF_FORMAT_ID)
1716 entry += sizeof(u64);
1718 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1720 size += sizeof(u64);
1724 event->read_size = size;
1727 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1729 struct perf_sample_data *data;
1732 if (sample_type & PERF_SAMPLE_IP)
1733 size += sizeof(data->ip);
1735 if (sample_type & PERF_SAMPLE_ADDR)
1736 size += sizeof(data->addr);
1738 if (sample_type & PERF_SAMPLE_PERIOD)
1739 size += sizeof(data->period);
1741 if (sample_type & PERF_SAMPLE_WEIGHT)
1742 size += sizeof(data->weight);
1744 if (sample_type & PERF_SAMPLE_READ)
1745 size += event->read_size;
1747 if (sample_type & PERF_SAMPLE_DATA_SRC)
1748 size += sizeof(data->data_src.val);
1750 if (sample_type & PERF_SAMPLE_TRANSACTION)
1751 size += sizeof(data->txn);
1753 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1754 size += sizeof(data->phys_addr);
1756 event->header_size = size;
1760 * Called at perf_event creation and when events are attached/detached from a
1763 static void perf_event__header_size(struct perf_event *event)
1765 __perf_event_read_size(event,
1766 event->group_leader->nr_siblings);
1767 __perf_event_header_size(event, event->attr.sample_type);
1770 static void perf_event__id_header_size(struct perf_event *event)
1772 struct perf_sample_data *data;
1773 u64 sample_type = event->attr.sample_type;
1776 if (sample_type & PERF_SAMPLE_TID)
1777 size += sizeof(data->tid_entry);
1779 if (sample_type & PERF_SAMPLE_TIME)
1780 size += sizeof(data->time);
1782 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1783 size += sizeof(data->id);
1785 if (sample_type & PERF_SAMPLE_ID)
1786 size += sizeof(data->id);
1788 if (sample_type & PERF_SAMPLE_STREAM_ID)
1789 size += sizeof(data->stream_id);
1791 if (sample_type & PERF_SAMPLE_CPU)
1792 size += sizeof(data->cpu_entry);
1794 event->id_header_size = size;
1797 static bool perf_event_validate_size(struct perf_event *event)
1800 * The values computed here will be over-written when we actually
1803 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1804 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1805 perf_event__id_header_size(event);
1808 * Sum the lot; should not exceed the 64k limit we have on records.
1809 * Conservative limit to allow for callchains and other variable fields.
1811 if (event->read_size + event->header_size +
1812 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1818 static void perf_group_attach(struct perf_event *event)
1820 struct perf_event *group_leader = event->group_leader, *pos;
1822 lockdep_assert_held(&event->ctx->lock);
1825 * We can have double attach due to group movement in perf_event_open.
1827 if (event->attach_state & PERF_ATTACH_GROUP)
1830 event->attach_state |= PERF_ATTACH_GROUP;
1832 if (group_leader == event)
1835 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1837 group_leader->group_caps &= event->event_caps;
1839 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1840 group_leader->nr_siblings++;
1842 perf_event__header_size(group_leader);
1844 for_each_sibling_event(pos, group_leader)
1845 perf_event__header_size(pos);
1849 * Remove an event from the lists for its context.
1850 * Must be called with ctx->mutex and ctx->lock held.
1853 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1855 WARN_ON_ONCE(event->ctx != ctx);
1856 lockdep_assert_held(&ctx->lock);
1859 * We can have double detach due to exit/hot-unplug + close.
1861 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1864 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1866 list_update_cgroup_event(event, ctx, false);
1869 if (event->attr.inherit_stat)
1872 list_del_rcu(&event->event_entry);
1874 if (event->group_leader == event)
1875 del_event_from_groups(event, ctx);
1878 * If event was in error state, then keep it
1879 * that way, otherwise bogus counts will be
1880 * returned on read(). The only way to get out
1881 * of error state is by explicit re-enabling
1884 if (event->state > PERF_EVENT_STATE_OFF)
1885 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1890 static void perf_group_detach(struct perf_event *event)
1892 struct perf_event *sibling, *tmp;
1893 struct perf_event_context *ctx = event->ctx;
1895 lockdep_assert_held(&ctx->lock);
1898 * We can have double detach due to exit/hot-unplug + close.
1900 if (!(event->attach_state & PERF_ATTACH_GROUP))
1903 event->attach_state &= ~PERF_ATTACH_GROUP;
1906 * If this is a sibling, remove it from its group.
1908 if (event->group_leader != event) {
1909 list_del_init(&event->sibling_list);
1910 event->group_leader->nr_siblings--;
1915 * If this was a group event with sibling events then
1916 * upgrade the siblings to singleton events by adding them
1917 * to whatever list we are on.
1919 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1921 sibling->group_leader = sibling;
1922 list_del_init(&sibling->sibling_list);
1924 /* Inherit group flags from the previous leader */
1925 sibling->group_caps = event->group_caps;
1927 if (!RB_EMPTY_NODE(&event->group_node)) {
1928 add_event_to_groups(sibling, event->ctx);
1930 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1931 struct list_head *list = sibling->attr.pinned ?
1932 &ctx->pinned_active : &ctx->flexible_active;
1934 list_add_tail(&sibling->active_list, list);
1938 WARN_ON_ONCE(sibling->ctx != event->ctx);
1942 perf_event__header_size(event->group_leader);
1944 for_each_sibling_event(tmp, event->group_leader)
1945 perf_event__header_size(tmp);
1948 static bool is_orphaned_event(struct perf_event *event)
1950 return event->state == PERF_EVENT_STATE_DEAD;
1953 static inline int __pmu_filter_match(struct perf_event *event)
1955 struct pmu *pmu = event->pmu;
1956 return pmu->filter_match ? pmu->filter_match(event) : 1;
1960 * Check whether we should attempt to schedule an event group based on
1961 * PMU-specific filtering. An event group can consist of HW and SW events,
1962 * potentially with a SW leader, so we must check all the filters, to
1963 * determine whether a group is schedulable:
1965 static inline int pmu_filter_match(struct perf_event *event)
1967 struct perf_event *sibling;
1969 if (!__pmu_filter_match(event))
1972 for_each_sibling_event(sibling, event) {
1973 if (!__pmu_filter_match(sibling))
1981 event_filter_match(struct perf_event *event)
1983 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1984 perf_cgroup_match(event) && pmu_filter_match(event);
1988 event_sched_out(struct perf_event *event,
1989 struct perf_cpu_context *cpuctx,
1990 struct perf_event_context *ctx)
1992 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1994 WARN_ON_ONCE(event->ctx != ctx);
1995 lockdep_assert_held(&ctx->lock);
1997 if (event->state != PERF_EVENT_STATE_ACTIVE)
2001 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2002 * we can schedule events _OUT_ individually through things like
2003 * __perf_remove_from_context().
2005 list_del_init(&event->active_list);
2007 perf_pmu_disable(event->pmu);
2009 event->pmu->del(event, 0);
2012 if (READ_ONCE(event->pending_disable) >= 0) {
2013 WRITE_ONCE(event->pending_disable, -1);
2014 state = PERF_EVENT_STATE_OFF;
2016 perf_event_set_state(event, state);
2018 if (!is_software_event(event))
2019 cpuctx->active_oncpu--;
2020 if (!--ctx->nr_active)
2021 perf_event_ctx_deactivate(ctx);
2022 if (event->attr.freq && event->attr.sample_freq)
2024 if (event->attr.exclusive || !cpuctx->active_oncpu)
2025 cpuctx->exclusive = 0;
2027 perf_pmu_enable(event->pmu);
2031 group_sched_out(struct perf_event *group_event,
2032 struct perf_cpu_context *cpuctx,
2033 struct perf_event_context *ctx)
2035 struct perf_event *event;
2037 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2040 perf_pmu_disable(ctx->pmu);
2042 event_sched_out(group_event, cpuctx, ctx);
2045 * Schedule out siblings (if any):
2047 for_each_sibling_event(event, group_event)
2048 event_sched_out(event, cpuctx, ctx);
2050 perf_pmu_enable(ctx->pmu);
2052 if (group_event->attr.exclusive)
2053 cpuctx->exclusive = 0;
2056 #define DETACH_GROUP 0x01UL
2059 * Cross CPU call to remove a performance event
2061 * We disable the event on the hardware level first. After that we
2062 * remove it from the context list.
2065 __perf_remove_from_context(struct perf_event *event,
2066 struct perf_cpu_context *cpuctx,
2067 struct perf_event_context *ctx,
2070 unsigned long flags = (unsigned long)info;
2072 if (ctx->is_active & EVENT_TIME) {
2073 update_context_time(ctx);
2074 update_cgrp_time_from_cpuctx(cpuctx);
2077 event_sched_out(event, cpuctx, ctx);
2078 if (flags & DETACH_GROUP)
2079 perf_group_detach(event);
2080 list_del_event(event, ctx);
2082 if (!ctx->nr_events && ctx->is_active) {
2085 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2086 cpuctx->task_ctx = NULL;
2092 * Remove the event from a task's (or a CPU's) list of events.
2094 * If event->ctx is a cloned context, callers must make sure that
2095 * every task struct that event->ctx->task could possibly point to
2096 * remains valid. This is OK when called from perf_release since
2097 * that only calls us on the top-level context, which can't be a clone.
2098 * When called from perf_event_exit_task, it's OK because the
2099 * context has been detached from its task.
2101 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2103 struct perf_event_context *ctx = event->ctx;
2105 lockdep_assert_held(&ctx->mutex);
2107 event_function_call(event, __perf_remove_from_context, (void *)flags);
2110 * The above event_function_call() can NO-OP when it hits
2111 * TASK_TOMBSTONE. In that case we must already have been detached
2112 * from the context (by perf_event_exit_event()) but the grouping
2113 * might still be in-tact.
2115 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2116 if ((flags & DETACH_GROUP) &&
2117 (event->attach_state & PERF_ATTACH_GROUP)) {
2119 * Since in that case we cannot possibly be scheduled, simply
2122 raw_spin_lock_irq(&ctx->lock);
2123 perf_group_detach(event);
2124 raw_spin_unlock_irq(&ctx->lock);
2129 * Cross CPU call to disable a performance event
2131 static void __perf_event_disable(struct perf_event *event,
2132 struct perf_cpu_context *cpuctx,
2133 struct perf_event_context *ctx,
2136 if (event->state < PERF_EVENT_STATE_INACTIVE)
2139 if (ctx->is_active & EVENT_TIME) {
2140 update_context_time(ctx);
2141 update_cgrp_time_from_event(event);
2144 if (event == event->group_leader)
2145 group_sched_out(event, cpuctx, ctx);
2147 event_sched_out(event, cpuctx, ctx);
2149 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2155 * If event->ctx is a cloned context, callers must make sure that
2156 * every task struct that event->ctx->task could possibly point to
2157 * remains valid. This condition is satisifed when called through
2158 * perf_event_for_each_child or perf_event_for_each because they
2159 * hold the top-level event's child_mutex, so any descendant that
2160 * goes to exit will block in perf_event_exit_event().
2162 * When called from perf_pending_event it's OK because event->ctx
2163 * is the current context on this CPU and preemption is disabled,
2164 * hence we can't get into perf_event_task_sched_out for this context.
2166 static void _perf_event_disable(struct perf_event *event)
2168 struct perf_event_context *ctx = event->ctx;
2170 raw_spin_lock_irq(&ctx->lock);
2171 if (event->state <= PERF_EVENT_STATE_OFF) {
2172 raw_spin_unlock_irq(&ctx->lock);
2175 raw_spin_unlock_irq(&ctx->lock);
2177 event_function_call(event, __perf_event_disable, NULL);
2180 void perf_event_disable_local(struct perf_event *event)
2182 event_function_local(event, __perf_event_disable, NULL);
2186 * Strictly speaking kernel users cannot create groups and therefore this
2187 * interface does not need the perf_event_ctx_lock() magic.
2189 void perf_event_disable(struct perf_event *event)
2191 struct perf_event_context *ctx;
2193 ctx = perf_event_ctx_lock(event);
2194 _perf_event_disable(event);
2195 perf_event_ctx_unlock(event, ctx);
2197 EXPORT_SYMBOL_GPL(perf_event_disable);
2199 void perf_event_disable_inatomic(struct perf_event *event)
2201 WRITE_ONCE(event->pending_disable, smp_processor_id());
2202 /* can fail, see perf_pending_event_disable() */
2203 irq_work_queue(&event->pending);
2206 static void perf_set_shadow_time(struct perf_event *event,
2207 struct perf_event_context *ctx)
2210 * use the correct time source for the time snapshot
2212 * We could get by without this by leveraging the
2213 * fact that to get to this function, the caller
2214 * has most likely already called update_context_time()
2215 * and update_cgrp_time_xx() and thus both timestamp
2216 * are identical (or very close). Given that tstamp is,
2217 * already adjusted for cgroup, we could say that:
2218 * tstamp - ctx->timestamp
2220 * tstamp - cgrp->timestamp.
2222 * Then, in perf_output_read(), the calculation would
2223 * work with no changes because:
2224 * - event is guaranteed scheduled in
2225 * - no scheduled out in between
2226 * - thus the timestamp would be the same
2228 * But this is a bit hairy.
2230 * So instead, we have an explicit cgroup call to remain
2231 * within the time time source all along. We believe it
2232 * is cleaner and simpler to understand.
2234 if (is_cgroup_event(event))
2235 perf_cgroup_set_shadow_time(event, event->tstamp);
2237 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2240 #define MAX_INTERRUPTS (~0ULL)
2242 static void perf_log_throttle(struct perf_event *event, int enable);
2243 static void perf_log_itrace_start(struct perf_event *event);
2246 event_sched_in(struct perf_event *event,
2247 struct perf_cpu_context *cpuctx,
2248 struct perf_event_context *ctx)
2252 lockdep_assert_held(&ctx->lock);
2254 if (event->state <= PERF_EVENT_STATE_OFF)
2257 WRITE_ONCE(event->oncpu, smp_processor_id());
2259 * Order event::oncpu write to happen before the ACTIVE state is
2260 * visible. This allows perf_event_{stop,read}() to observe the correct
2261 * ->oncpu if it sees ACTIVE.
2264 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2267 * Unthrottle events, since we scheduled we might have missed several
2268 * ticks already, also for a heavily scheduling task there is little
2269 * guarantee it'll get a tick in a timely manner.
2271 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2272 perf_log_throttle(event, 1);
2273 event->hw.interrupts = 0;
2276 perf_pmu_disable(event->pmu);
2278 perf_set_shadow_time(event, ctx);
2280 perf_log_itrace_start(event);
2282 if (event->pmu->add(event, PERF_EF_START)) {
2283 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2289 if (!is_software_event(event))
2290 cpuctx->active_oncpu++;
2291 if (!ctx->nr_active++)
2292 perf_event_ctx_activate(ctx);
2293 if (event->attr.freq && event->attr.sample_freq)
2296 if (event->attr.exclusive)
2297 cpuctx->exclusive = 1;
2300 perf_pmu_enable(event->pmu);
2306 group_sched_in(struct perf_event *group_event,
2307 struct perf_cpu_context *cpuctx,
2308 struct perf_event_context *ctx)
2310 struct perf_event *event, *partial_group = NULL;
2311 struct pmu *pmu = ctx->pmu;
2313 if (group_event->state == PERF_EVENT_STATE_OFF)
2316 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2318 if (event_sched_in(group_event, cpuctx, ctx)) {
2319 pmu->cancel_txn(pmu);
2320 perf_mux_hrtimer_restart(cpuctx);
2325 * Schedule in siblings as one group (if any):
2327 for_each_sibling_event(event, group_event) {
2328 if (event_sched_in(event, cpuctx, ctx)) {
2329 partial_group = event;
2334 if (!pmu->commit_txn(pmu))
2339 * Groups can be scheduled in as one unit only, so undo any
2340 * partial group before returning:
2341 * The events up to the failed event are scheduled out normally.
2343 for_each_sibling_event(event, group_event) {
2344 if (event == partial_group)
2347 event_sched_out(event, cpuctx, ctx);
2349 event_sched_out(group_event, cpuctx, ctx);
2351 pmu->cancel_txn(pmu);
2353 perf_mux_hrtimer_restart(cpuctx);
2359 * Work out whether we can put this event group on the CPU now.
2361 static int group_can_go_on(struct perf_event *event,
2362 struct perf_cpu_context *cpuctx,
2366 * Groups consisting entirely of software events can always go on.
2368 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2371 * If an exclusive group is already on, no other hardware
2374 if (cpuctx->exclusive)
2377 * If this group is exclusive and there are already
2378 * events on the CPU, it can't go on.
2380 if (event->attr.exclusive && cpuctx->active_oncpu)
2383 * Otherwise, try to add it if all previous groups were able
2389 static void add_event_to_ctx(struct perf_event *event,
2390 struct perf_event_context *ctx)
2392 list_add_event(event, ctx);
2393 perf_group_attach(event);
2396 static void ctx_sched_out(struct perf_event_context *ctx,
2397 struct perf_cpu_context *cpuctx,
2398 enum event_type_t event_type);
2400 ctx_sched_in(struct perf_event_context *ctx,
2401 struct perf_cpu_context *cpuctx,
2402 enum event_type_t event_type,
2403 struct task_struct *task);
2405 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2406 struct perf_event_context *ctx,
2407 enum event_type_t event_type)
2409 if (!cpuctx->task_ctx)
2412 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2415 ctx_sched_out(ctx, cpuctx, event_type);
2418 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2419 struct perf_event_context *ctx,
2420 struct task_struct *task)
2422 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2424 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2425 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2427 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2431 * We want to maintain the following priority of scheduling:
2432 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2433 * - task pinned (EVENT_PINNED)
2434 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2435 * - task flexible (EVENT_FLEXIBLE).
2437 * In order to avoid unscheduling and scheduling back in everything every
2438 * time an event is added, only do it for the groups of equal priority and
2441 * This can be called after a batch operation on task events, in which case
2442 * event_type is a bit mask of the types of events involved. For CPU events,
2443 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2445 static void ctx_resched(struct perf_cpu_context *cpuctx,
2446 struct perf_event_context *task_ctx,
2447 enum event_type_t event_type)
2449 enum event_type_t ctx_event_type;
2450 bool cpu_event = !!(event_type & EVENT_CPU);
2453 * If pinned groups are involved, flexible groups also need to be
2456 if (event_type & EVENT_PINNED)
2457 event_type |= EVENT_FLEXIBLE;
2459 ctx_event_type = event_type & EVENT_ALL;
2461 perf_pmu_disable(cpuctx->ctx.pmu);
2463 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2466 * Decide which cpu ctx groups to schedule out based on the types
2467 * of events that caused rescheduling:
2468 * - EVENT_CPU: schedule out corresponding groups;
2469 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2470 * - otherwise, do nothing more.
2473 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2474 else if (ctx_event_type & EVENT_PINNED)
2475 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2477 perf_event_sched_in(cpuctx, task_ctx, current);
2478 perf_pmu_enable(cpuctx->ctx.pmu);
2481 void perf_pmu_resched(struct pmu *pmu)
2483 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2484 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2486 perf_ctx_lock(cpuctx, task_ctx);
2487 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2488 perf_ctx_unlock(cpuctx, task_ctx);
2492 * Cross CPU call to install and enable a performance event
2494 * Very similar to remote_function() + event_function() but cannot assume that
2495 * things like ctx->is_active and cpuctx->task_ctx are set.
2497 static int __perf_install_in_context(void *info)
2499 struct perf_event *event = info;
2500 struct perf_event_context *ctx = event->ctx;
2501 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2502 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2503 bool reprogram = true;
2506 raw_spin_lock(&cpuctx->ctx.lock);
2508 raw_spin_lock(&ctx->lock);
2511 reprogram = (ctx->task == current);
2514 * If the task is running, it must be running on this CPU,
2515 * otherwise we cannot reprogram things.
2517 * If its not running, we don't care, ctx->lock will
2518 * serialize against it becoming runnable.
2520 if (task_curr(ctx->task) && !reprogram) {
2525 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2526 } else if (task_ctx) {
2527 raw_spin_lock(&task_ctx->lock);
2530 #ifdef CONFIG_CGROUP_PERF
2531 if (is_cgroup_event(event)) {
2533 * If the current cgroup doesn't match the event's
2534 * cgroup, we should not try to schedule it.
2536 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2537 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2538 event->cgrp->css.cgroup);
2543 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2544 add_event_to_ctx(event, ctx);
2545 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2547 add_event_to_ctx(event, ctx);
2551 perf_ctx_unlock(cpuctx, task_ctx);
2556 static bool exclusive_event_installable(struct perf_event *event,
2557 struct perf_event_context *ctx);
2560 * Attach a performance event to a context.
2562 * Very similar to event_function_call, see comment there.
2565 perf_install_in_context(struct perf_event_context *ctx,
2566 struct perf_event *event,
2569 struct task_struct *task = READ_ONCE(ctx->task);
2571 lockdep_assert_held(&ctx->mutex);
2573 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2575 if (event->cpu != -1)
2579 * Ensures that if we can observe event->ctx, both the event and ctx
2580 * will be 'complete'. See perf_iterate_sb_cpu().
2582 smp_store_release(&event->ctx, ctx);
2585 cpu_function_call(cpu, __perf_install_in_context, event);
2590 * Should not happen, we validate the ctx is still alive before calling.
2592 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2596 * Installing events is tricky because we cannot rely on ctx->is_active
2597 * to be set in case this is the nr_events 0 -> 1 transition.
2599 * Instead we use task_curr(), which tells us if the task is running.
2600 * However, since we use task_curr() outside of rq::lock, we can race
2601 * against the actual state. This means the result can be wrong.
2603 * If we get a false positive, we retry, this is harmless.
2605 * If we get a false negative, things are complicated. If we are after
2606 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2607 * value must be correct. If we're before, it doesn't matter since
2608 * perf_event_context_sched_in() will program the counter.
2610 * However, this hinges on the remote context switch having observed
2611 * our task->perf_event_ctxp[] store, such that it will in fact take
2612 * ctx::lock in perf_event_context_sched_in().
2614 * We do this by task_function_call(), if the IPI fails to hit the task
2615 * we know any future context switch of task must see the
2616 * perf_event_ctpx[] store.
2620 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2621 * task_cpu() load, such that if the IPI then does not find the task
2622 * running, a future context switch of that task must observe the
2627 if (!task_function_call(task, __perf_install_in_context, event))
2630 raw_spin_lock_irq(&ctx->lock);
2632 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2634 * Cannot happen because we already checked above (which also
2635 * cannot happen), and we hold ctx->mutex, which serializes us
2636 * against perf_event_exit_task_context().
2638 raw_spin_unlock_irq(&ctx->lock);
2642 * If the task is not running, ctx->lock will avoid it becoming so,
2643 * thus we can safely install the event.
2645 if (task_curr(task)) {
2646 raw_spin_unlock_irq(&ctx->lock);
2649 add_event_to_ctx(event, ctx);
2650 raw_spin_unlock_irq(&ctx->lock);
2654 * Cross CPU call to enable a performance event
2656 static void __perf_event_enable(struct perf_event *event,
2657 struct perf_cpu_context *cpuctx,
2658 struct perf_event_context *ctx,
2661 struct perf_event *leader = event->group_leader;
2662 struct perf_event_context *task_ctx;
2664 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2665 event->state <= PERF_EVENT_STATE_ERROR)
2669 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2671 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2673 if (!ctx->is_active)
2676 if (!event_filter_match(event)) {
2677 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2682 * If the event is in a group and isn't the group leader,
2683 * then don't put it on unless the group is on.
2685 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2686 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2690 task_ctx = cpuctx->task_ctx;
2692 WARN_ON_ONCE(task_ctx != ctx);
2694 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2700 * If event->ctx is a cloned context, callers must make sure that
2701 * every task struct that event->ctx->task could possibly point to
2702 * remains valid. This condition is satisfied when called through
2703 * perf_event_for_each_child or perf_event_for_each as described
2704 * for perf_event_disable.
2706 static void _perf_event_enable(struct perf_event *event)
2708 struct perf_event_context *ctx = event->ctx;
2710 raw_spin_lock_irq(&ctx->lock);
2711 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2712 event->state < PERF_EVENT_STATE_ERROR) {
2713 raw_spin_unlock_irq(&ctx->lock);
2718 * If the event is in error state, clear that first.
2720 * That way, if we see the event in error state below, we know that it
2721 * has gone back into error state, as distinct from the task having
2722 * been scheduled away before the cross-call arrived.
2724 if (event->state == PERF_EVENT_STATE_ERROR)
2725 event->state = PERF_EVENT_STATE_OFF;
2726 raw_spin_unlock_irq(&ctx->lock);
2728 event_function_call(event, __perf_event_enable, NULL);
2732 * See perf_event_disable();
2734 void perf_event_enable(struct perf_event *event)
2736 struct perf_event_context *ctx;
2738 ctx = perf_event_ctx_lock(event);
2739 _perf_event_enable(event);
2740 perf_event_ctx_unlock(event, ctx);
2742 EXPORT_SYMBOL_GPL(perf_event_enable);
2744 struct stop_event_data {
2745 struct perf_event *event;
2746 unsigned int restart;
2749 static int __perf_event_stop(void *info)
2751 struct stop_event_data *sd = info;
2752 struct perf_event *event = sd->event;
2754 /* if it's already INACTIVE, do nothing */
2755 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2758 /* matches smp_wmb() in event_sched_in() */
2762 * There is a window with interrupts enabled before we get here,
2763 * so we need to check again lest we try to stop another CPU's event.
2765 if (READ_ONCE(event->oncpu) != smp_processor_id())
2768 event->pmu->stop(event, PERF_EF_UPDATE);
2771 * May race with the actual stop (through perf_pmu_output_stop()),
2772 * but it is only used for events with AUX ring buffer, and such
2773 * events will refuse to restart because of rb::aux_mmap_count==0,
2774 * see comments in perf_aux_output_begin().
2776 * Since this is happening on an event-local CPU, no trace is lost
2780 event->pmu->start(event, 0);
2785 static int perf_event_stop(struct perf_event *event, int restart)
2787 struct stop_event_data sd = {
2794 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2797 /* matches smp_wmb() in event_sched_in() */
2801 * We only want to restart ACTIVE events, so if the event goes
2802 * inactive here (event->oncpu==-1), there's nothing more to do;
2803 * fall through with ret==-ENXIO.
2805 ret = cpu_function_call(READ_ONCE(event->oncpu),
2806 __perf_event_stop, &sd);
2807 } while (ret == -EAGAIN);
2813 * In order to contain the amount of racy and tricky in the address filter
2814 * configuration management, it is a two part process:
2816 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2817 * we update the addresses of corresponding vmas in
2818 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2819 * (p2) when an event is scheduled in (pmu::add), it calls
2820 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2821 * if the generation has changed since the previous call.
2823 * If (p1) happens while the event is active, we restart it to force (p2).
2825 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2826 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2828 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2829 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2831 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2834 void perf_event_addr_filters_sync(struct perf_event *event)
2836 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2838 if (!has_addr_filter(event))
2841 raw_spin_lock(&ifh->lock);
2842 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2843 event->pmu->addr_filters_sync(event);
2844 event->hw.addr_filters_gen = event->addr_filters_gen;
2846 raw_spin_unlock(&ifh->lock);
2848 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2850 static int _perf_event_refresh(struct perf_event *event, int refresh)
2853 * not supported on inherited events
2855 if (event->attr.inherit || !is_sampling_event(event))
2858 atomic_add(refresh, &event->event_limit);
2859 _perf_event_enable(event);
2865 * See perf_event_disable()
2867 int perf_event_refresh(struct perf_event *event, int refresh)
2869 struct perf_event_context *ctx;
2872 ctx = perf_event_ctx_lock(event);
2873 ret = _perf_event_refresh(event, refresh);
2874 perf_event_ctx_unlock(event, ctx);
2878 EXPORT_SYMBOL_GPL(perf_event_refresh);
2880 static int perf_event_modify_breakpoint(struct perf_event *bp,
2881 struct perf_event_attr *attr)
2885 _perf_event_disable(bp);
2887 err = modify_user_hw_breakpoint_check(bp, attr, true);
2889 if (!bp->attr.disabled)
2890 _perf_event_enable(bp);
2895 static int perf_event_modify_attr(struct perf_event *event,
2896 struct perf_event_attr *attr)
2898 if (event->attr.type != attr->type)
2901 switch (event->attr.type) {
2902 case PERF_TYPE_BREAKPOINT:
2903 return perf_event_modify_breakpoint(event, attr);
2905 /* Place holder for future additions. */
2910 static void ctx_sched_out(struct perf_event_context *ctx,
2911 struct perf_cpu_context *cpuctx,
2912 enum event_type_t event_type)
2914 struct perf_event *event, *tmp;
2915 int is_active = ctx->is_active;
2917 lockdep_assert_held(&ctx->lock);
2919 if (likely(!ctx->nr_events)) {
2921 * See __perf_remove_from_context().
2923 WARN_ON_ONCE(ctx->is_active);
2925 WARN_ON_ONCE(cpuctx->task_ctx);
2929 ctx->is_active &= ~event_type;
2930 if (!(ctx->is_active & EVENT_ALL))
2934 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2935 if (!ctx->is_active)
2936 cpuctx->task_ctx = NULL;
2940 * Always update time if it was set; not only when it changes.
2941 * Otherwise we can 'forget' to update time for any but the last
2942 * context we sched out. For example:
2944 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2945 * ctx_sched_out(.event_type = EVENT_PINNED)
2947 * would only update time for the pinned events.
2949 if (is_active & EVENT_TIME) {
2950 /* update (and stop) ctx time */
2951 update_context_time(ctx);
2952 update_cgrp_time_from_cpuctx(cpuctx);
2955 is_active ^= ctx->is_active; /* changed bits */
2957 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2961 * If we had been multiplexing, no rotations are necessary, now no events
2964 ctx->rotate_necessary = 0;
2966 perf_pmu_disable(ctx->pmu);
2967 if (is_active & EVENT_PINNED) {
2968 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2969 group_sched_out(event, cpuctx, ctx);
2972 if (is_active & EVENT_FLEXIBLE) {
2973 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2974 group_sched_out(event, cpuctx, ctx);
2976 perf_pmu_enable(ctx->pmu);
2980 * Test whether two contexts are equivalent, i.e. whether they have both been
2981 * cloned from the same version of the same context.
2983 * Equivalence is measured using a generation number in the context that is
2984 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2985 * and list_del_event().
2987 static int context_equiv(struct perf_event_context *ctx1,
2988 struct perf_event_context *ctx2)
2990 lockdep_assert_held(&ctx1->lock);
2991 lockdep_assert_held(&ctx2->lock);
2993 /* Pinning disables the swap optimization */
2994 if (ctx1->pin_count || ctx2->pin_count)
2997 /* If ctx1 is the parent of ctx2 */
2998 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3001 /* If ctx2 is the parent of ctx1 */
3002 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3006 * If ctx1 and ctx2 have the same parent; we flatten the parent
3007 * hierarchy, see perf_event_init_context().
3009 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3010 ctx1->parent_gen == ctx2->parent_gen)
3017 static void __perf_event_sync_stat(struct perf_event *event,
3018 struct perf_event *next_event)
3022 if (!event->attr.inherit_stat)
3026 * Update the event value, we cannot use perf_event_read()
3027 * because we're in the middle of a context switch and have IRQs
3028 * disabled, which upsets smp_call_function_single(), however
3029 * we know the event must be on the current CPU, therefore we
3030 * don't need to use it.
3032 if (event->state == PERF_EVENT_STATE_ACTIVE)
3033 event->pmu->read(event);
3035 perf_event_update_time(event);
3038 * In order to keep per-task stats reliable we need to flip the event
3039 * values when we flip the contexts.
3041 value = local64_read(&next_event->count);
3042 value = local64_xchg(&event->count, value);
3043 local64_set(&next_event->count, value);
3045 swap(event->total_time_enabled, next_event->total_time_enabled);
3046 swap(event->total_time_running, next_event->total_time_running);
3049 * Since we swizzled the values, update the user visible data too.
3051 perf_event_update_userpage(event);
3052 perf_event_update_userpage(next_event);
3055 static void perf_event_sync_stat(struct perf_event_context *ctx,
3056 struct perf_event_context *next_ctx)
3058 struct perf_event *event, *next_event;
3063 update_context_time(ctx);
3065 event = list_first_entry(&ctx->event_list,
3066 struct perf_event, event_entry);
3068 next_event = list_first_entry(&next_ctx->event_list,
3069 struct perf_event, event_entry);
3071 while (&event->event_entry != &ctx->event_list &&
3072 &next_event->event_entry != &next_ctx->event_list) {
3074 __perf_event_sync_stat(event, next_event);
3076 event = list_next_entry(event, event_entry);
3077 next_event = list_next_entry(next_event, event_entry);
3081 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3082 struct task_struct *next)
3084 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3085 struct perf_event_context *next_ctx;
3086 struct perf_event_context *parent, *next_parent;
3087 struct perf_cpu_context *cpuctx;
3093 cpuctx = __get_cpu_context(ctx);
3094 if (!cpuctx->task_ctx)
3098 next_ctx = next->perf_event_ctxp[ctxn];
3102 parent = rcu_dereference(ctx->parent_ctx);
3103 next_parent = rcu_dereference(next_ctx->parent_ctx);
3105 /* If neither context have a parent context; they cannot be clones. */
3106 if (!parent && !next_parent)
3109 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3111 * Looks like the two contexts are clones, so we might be
3112 * able to optimize the context switch. We lock both
3113 * contexts and check that they are clones under the
3114 * lock (including re-checking that neither has been
3115 * uncloned in the meantime). It doesn't matter which
3116 * order we take the locks because no other cpu could
3117 * be trying to lock both of these tasks.
3119 raw_spin_lock(&ctx->lock);
3120 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3121 if (context_equiv(ctx, next_ctx)) {
3122 WRITE_ONCE(ctx->task, next);
3123 WRITE_ONCE(next_ctx->task, task);
3125 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3128 * RCU_INIT_POINTER here is safe because we've not
3129 * modified the ctx and the above modification of
3130 * ctx->task and ctx->task_ctx_data are immaterial
3131 * since those values are always verified under
3132 * ctx->lock which we're now holding.
3134 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3135 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3139 perf_event_sync_stat(ctx, next_ctx);
3141 raw_spin_unlock(&next_ctx->lock);
3142 raw_spin_unlock(&ctx->lock);
3148 raw_spin_lock(&ctx->lock);
3149 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3150 raw_spin_unlock(&ctx->lock);
3154 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3156 void perf_sched_cb_dec(struct pmu *pmu)
3158 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3160 this_cpu_dec(perf_sched_cb_usages);
3162 if (!--cpuctx->sched_cb_usage)
3163 list_del(&cpuctx->sched_cb_entry);
3167 void perf_sched_cb_inc(struct pmu *pmu)
3169 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3171 if (!cpuctx->sched_cb_usage++)
3172 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3174 this_cpu_inc(perf_sched_cb_usages);
3178 * This function provides the context switch callback to the lower code
3179 * layer. It is invoked ONLY when the context switch callback is enabled.
3181 * This callback is relevant even to per-cpu events; for example multi event
3182 * PEBS requires this to provide PID/TID information. This requires we flush
3183 * all queued PEBS records before we context switch to a new task.
3185 static void perf_pmu_sched_task(struct task_struct *prev,
3186 struct task_struct *next,
3189 struct perf_cpu_context *cpuctx;
3195 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3196 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3198 if (WARN_ON_ONCE(!pmu->sched_task))
3201 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3202 perf_pmu_disable(pmu);
3204 pmu->sched_task(cpuctx->task_ctx, sched_in);
3206 perf_pmu_enable(pmu);
3207 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3211 static void perf_event_switch(struct task_struct *task,
3212 struct task_struct *next_prev, bool sched_in);
3214 #define for_each_task_context_nr(ctxn) \
3215 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3218 * Called from scheduler to remove the events of the current task,
3219 * with interrupts disabled.
3221 * We stop each event and update the event value in event->count.
3223 * This does not protect us against NMI, but disable()
3224 * sets the disabled bit in the control field of event _before_
3225 * accessing the event control register. If a NMI hits, then it will
3226 * not restart the event.
3228 void __perf_event_task_sched_out(struct task_struct *task,
3229 struct task_struct *next)
3233 if (__this_cpu_read(perf_sched_cb_usages))
3234 perf_pmu_sched_task(task, next, false);
3236 if (atomic_read(&nr_switch_events))
3237 perf_event_switch(task, next, false);
3239 for_each_task_context_nr(ctxn)
3240 perf_event_context_sched_out(task, ctxn, next);
3243 * if cgroup events exist on this CPU, then we need
3244 * to check if we have to switch out PMU state.
3245 * cgroup event are system-wide mode only
3247 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3248 perf_cgroup_sched_out(task, next);
3252 * Called with IRQs disabled
3254 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3255 enum event_type_t event_type)
3257 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3260 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3261 int (*func)(struct perf_event *, void *), void *data)
3263 struct perf_event **evt, *evt1, *evt2;
3266 evt1 = perf_event_groups_first(groups, -1);
3267 evt2 = perf_event_groups_first(groups, cpu);
3269 while (evt1 || evt2) {
3271 if (evt1->group_index < evt2->group_index)
3281 ret = func(*evt, data);
3285 *evt = perf_event_groups_next(*evt);
3291 struct sched_in_data {
3292 struct perf_event_context *ctx;
3293 struct perf_cpu_context *cpuctx;
3297 static int pinned_sched_in(struct perf_event *event, void *data)
3299 struct sched_in_data *sid = data;
3301 if (event->state <= PERF_EVENT_STATE_OFF)
3304 if (!event_filter_match(event))
3307 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3308 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3309 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3313 * If this pinned group hasn't been scheduled,
3314 * put it in error state.
3316 if (event->state == PERF_EVENT_STATE_INACTIVE)
3317 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3322 static int flexible_sched_in(struct perf_event *event, void *data)
3324 struct sched_in_data *sid = data;
3326 if (event->state <= PERF_EVENT_STATE_OFF)
3329 if (!event_filter_match(event))
3332 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3333 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3335 sid->can_add_hw = 0;
3336 sid->ctx->rotate_necessary = 1;
3339 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3346 ctx_pinned_sched_in(struct perf_event_context *ctx,
3347 struct perf_cpu_context *cpuctx)
3349 struct sched_in_data sid = {
3355 visit_groups_merge(&ctx->pinned_groups,
3357 pinned_sched_in, &sid);
3361 ctx_flexible_sched_in(struct perf_event_context *ctx,
3362 struct perf_cpu_context *cpuctx)
3364 struct sched_in_data sid = {
3370 visit_groups_merge(&ctx->flexible_groups,
3372 flexible_sched_in, &sid);
3376 ctx_sched_in(struct perf_event_context *ctx,
3377 struct perf_cpu_context *cpuctx,
3378 enum event_type_t event_type,
3379 struct task_struct *task)
3381 int is_active = ctx->is_active;
3384 lockdep_assert_held(&ctx->lock);
3386 if (likely(!ctx->nr_events))
3389 ctx->is_active |= (event_type | EVENT_TIME);
3392 cpuctx->task_ctx = ctx;
3394 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3397 is_active ^= ctx->is_active; /* changed bits */
3399 if (is_active & EVENT_TIME) {
3400 /* start ctx time */
3402 ctx->timestamp = now;
3403 perf_cgroup_set_timestamp(task, ctx);
3407 * First go through the list and put on any pinned groups
3408 * in order to give them the best chance of going on.
3410 if (is_active & EVENT_PINNED)
3411 ctx_pinned_sched_in(ctx, cpuctx);
3413 /* Then walk through the lower prio flexible groups */
3414 if (is_active & EVENT_FLEXIBLE)
3415 ctx_flexible_sched_in(ctx, cpuctx);
3418 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3419 enum event_type_t event_type,
3420 struct task_struct *task)
3422 struct perf_event_context *ctx = &cpuctx->ctx;
3424 ctx_sched_in(ctx, cpuctx, event_type, task);
3427 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3428 struct task_struct *task)
3430 struct perf_cpu_context *cpuctx;
3432 cpuctx = __get_cpu_context(ctx);
3433 if (cpuctx->task_ctx == ctx)
3436 perf_ctx_lock(cpuctx, ctx);
3438 * We must check ctx->nr_events while holding ctx->lock, such
3439 * that we serialize against perf_install_in_context().
3441 if (!ctx->nr_events)
3444 perf_pmu_disable(ctx->pmu);
3446 * We want to keep the following priority order:
3447 * cpu pinned (that don't need to move), task pinned,
3448 * cpu flexible, task flexible.
3450 * However, if task's ctx is not carrying any pinned
3451 * events, no need to flip the cpuctx's events around.
3453 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3454 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3455 perf_event_sched_in(cpuctx, ctx, task);
3456 perf_pmu_enable(ctx->pmu);
3459 perf_ctx_unlock(cpuctx, ctx);
3463 * Called from scheduler to add the events of the current task
3464 * with interrupts disabled.
3466 * We restore the event value and then enable it.
3468 * This does not protect us against NMI, but enable()
3469 * sets the enabled bit in the control field of event _before_
3470 * accessing the event control register. If a NMI hits, then it will
3471 * keep the event running.
3473 void __perf_event_task_sched_in(struct task_struct *prev,
3474 struct task_struct *task)
3476 struct perf_event_context *ctx;
3480 * If cgroup events exist on this CPU, then we need to check if we have
3481 * to switch in PMU state; cgroup event are system-wide mode only.
3483 * Since cgroup events are CPU events, we must schedule these in before
3484 * we schedule in the task events.
3486 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3487 perf_cgroup_sched_in(prev, task);
3489 for_each_task_context_nr(ctxn) {
3490 ctx = task->perf_event_ctxp[ctxn];
3494 perf_event_context_sched_in(ctx, task);
3497 if (atomic_read(&nr_switch_events))
3498 perf_event_switch(task, prev, true);
3500 if (__this_cpu_read(perf_sched_cb_usages))
3501 perf_pmu_sched_task(prev, task, true);
3504 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3506 u64 frequency = event->attr.sample_freq;
3507 u64 sec = NSEC_PER_SEC;
3508 u64 divisor, dividend;
3510 int count_fls, nsec_fls, frequency_fls, sec_fls;
3512 count_fls = fls64(count);
3513 nsec_fls = fls64(nsec);
3514 frequency_fls = fls64(frequency);
3518 * We got @count in @nsec, with a target of sample_freq HZ
3519 * the target period becomes:
3522 * period = -------------------
3523 * @nsec * sample_freq
3528 * Reduce accuracy by one bit such that @a and @b converge
3529 * to a similar magnitude.
3531 #define REDUCE_FLS(a, b) \
3533 if (a##_fls > b##_fls) { \
3543 * Reduce accuracy until either term fits in a u64, then proceed with
3544 * the other, so that finally we can do a u64/u64 division.
3546 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3547 REDUCE_FLS(nsec, frequency);
3548 REDUCE_FLS(sec, count);
3551 if (count_fls + sec_fls > 64) {
3552 divisor = nsec * frequency;
3554 while (count_fls + sec_fls > 64) {
3555 REDUCE_FLS(count, sec);
3559 dividend = count * sec;
3561 dividend = count * sec;
3563 while (nsec_fls + frequency_fls > 64) {
3564 REDUCE_FLS(nsec, frequency);
3568 divisor = nsec * frequency;
3574 return div64_u64(dividend, divisor);
3577 static DEFINE_PER_CPU(int, perf_throttled_count);
3578 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3580 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3582 struct hw_perf_event *hwc = &event->hw;
3583 s64 period, sample_period;
3586 period = perf_calculate_period(event, nsec, count);
3588 delta = (s64)(period - hwc->sample_period);
3589 delta = (delta + 7) / 8; /* low pass filter */
3591 sample_period = hwc->sample_period + delta;
3596 hwc->sample_period = sample_period;
3598 if (local64_read(&hwc->period_left) > 8*sample_period) {
3600 event->pmu->stop(event, PERF_EF_UPDATE);
3602 local64_set(&hwc->period_left, 0);
3605 event->pmu->start(event, PERF_EF_RELOAD);
3610 * combine freq adjustment with unthrottling to avoid two passes over the
3611 * events. At the same time, make sure, having freq events does not change
3612 * the rate of unthrottling as that would introduce bias.
3614 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3617 struct perf_event *event;
3618 struct hw_perf_event *hwc;
3619 u64 now, period = TICK_NSEC;
3623 * only need to iterate over all events iff:
3624 * - context have events in frequency mode (needs freq adjust)
3625 * - there are events to unthrottle on this cpu
3627 if (!(ctx->nr_freq || needs_unthr))
3630 raw_spin_lock(&ctx->lock);
3631 perf_pmu_disable(ctx->pmu);
3633 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3634 if (event->state != PERF_EVENT_STATE_ACTIVE)
3637 if (!event_filter_match(event))
3640 perf_pmu_disable(event->pmu);
3644 if (hwc->interrupts == MAX_INTERRUPTS) {
3645 hwc->interrupts = 0;
3646 perf_log_throttle(event, 1);
3647 event->pmu->start(event, 0);
3650 if (!event->attr.freq || !event->attr.sample_freq)
3654 * stop the event and update event->count
3656 event->pmu->stop(event, PERF_EF_UPDATE);
3658 now = local64_read(&event->count);
3659 delta = now - hwc->freq_count_stamp;
3660 hwc->freq_count_stamp = now;
3664 * reload only if value has changed
3665 * we have stopped the event so tell that
3666 * to perf_adjust_period() to avoid stopping it
3670 perf_adjust_period(event, period, delta, false);
3672 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3674 perf_pmu_enable(event->pmu);
3677 perf_pmu_enable(ctx->pmu);
3678 raw_spin_unlock(&ctx->lock);
3682 * Move @event to the tail of the @ctx's elegible events.
3684 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3687 * Rotate the first entry last of non-pinned groups. Rotation might be
3688 * disabled by the inheritance code.
3690 if (ctx->rotate_disable)
3693 perf_event_groups_delete(&ctx->flexible_groups, event);
3694 perf_event_groups_insert(&ctx->flexible_groups, event);
3697 static inline struct perf_event *
3698 ctx_first_active(struct perf_event_context *ctx)
3700 return list_first_entry_or_null(&ctx->flexible_active,
3701 struct perf_event, active_list);
3704 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3706 struct perf_event *cpu_event = NULL, *task_event = NULL;
3707 struct perf_event_context *task_ctx = NULL;
3708 int cpu_rotate, task_rotate;
3711 * Since we run this from IRQ context, nobody can install new
3712 * events, thus the event count values are stable.
3715 cpu_rotate = cpuctx->ctx.rotate_necessary;
3716 task_ctx = cpuctx->task_ctx;
3717 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3719 if (!(cpu_rotate || task_rotate))
3722 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3723 perf_pmu_disable(cpuctx->ctx.pmu);
3726 task_event = ctx_first_active(task_ctx);
3728 cpu_event = ctx_first_active(&cpuctx->ctx);
3731 * As per the order given at ctx_resched() first 'pop' task flexible
3732 * and then, if needed CPU flexible.
3734 if (task_event || (task_ctx && cpu_event))
3735 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3737 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3740 rotate_ctx(task_ctx, task_event);
3742 rotate_ctx(&cpuctx->ctx, cpu_event);
3744 perf_event_sched_in(cpuctx, task_ctx, current);
3746 perf_pmu_enable(cpuctx->ctx.pmu);
3747 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3752 void perf_event_task_tick(void)
3754 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3755 struct perf_event_context *ctx, *tmp;
3758 lockdep_assert_irqs_disabled();
3760 __this_cpu_inc(perf_throttled_seq);
3761 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3762 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3764 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3765 perf_adjust_freq_unthr_context(ctx, throttled);
3768 static int event_enable_on_exec(struct perf_event *event,
3769 struct perf_event_context *ctx)
3771 if (!event->attr.enable_on_exec)
3774 event->attr.enable_on_exec = 0;
3775 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3778 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3784 * Enable all of a task's events that have been marked enable-on-exec.
3785 * This expects task == current.
3787 static void perf_event_enable_on_exec(int ctxn)
3789 struct perf_event_context *ctx, *clone_ctx = NULL;
3790 enum event_type_t event_type = 0;
3791 struct perf_cpu_context *cpuctx;
3792 struct perf_event *event;
3793 unsigned long flags;
3796 local_irq_save(flags);
3797 ctx = current->perf_event_ctxp[ctxn];
3798 if (!ctx || !ctx->nr_events)
3801 cpuctx = __get_cpu_context(ctx);
3802 perf_ctx_lock(cpuctx, ctx);
3803 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3804 list_for_each_entry(event, &ctx->event_list, event_entry) {
3805 enabled |= event_enable_on_exec(event, ctx);
3806 event_type |= get_event_type(event);
3810 * Unclone and reschedule this context if we enabled any event.
3813 clone_ctx = unclone_ctx(ctx);
3814 ctx_resched(cpuctx, ctx, event_type);
3816 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3818 perf_ctx_unlock(cpuctx, ctx);
3821 local_irq_restore(flags);
3827 struct perf_read_data {
3828 struct perf_event *event;
3833 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3835 u16 local_pkg, event_pkg;
3837 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3838 int local_cpu = smp_processor_id();
3840 event_pkg = topology_physical_package_id(event_cpu);
3841 local_pkg = topology_physical_package_id(local_cpu);
3843 if (event_pkg == local_pkg)
3851 * Cross CPU call to read the hardware event
3853 static void __perf_event_read(void *info)
3855 struct perf_read_data *data = info;
3856 struct perf_event *sub, *event = data->event;
3857 struct perf_event_context *ctx = event->ctx;
3858 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3859 struct pmu *pmu = event->pmu;
3862 * If this is a task context, we need to check whether it is
3863 * the current task context of this cpu. If not it has been
3864 * scheduled out before the smp call arrived. In that case
3865 * event->count would have been updated to a recent sample
3866 * when the event was scheduled out.
3868 if (ctx->task && cpuctx->task_ctx != ctx)
3871 raw_spin_lock(&ctx->lock);
3872 if (ctx->is_active & EVENT_TIME) {
3873 update_context_time(ctx);
3874 update_cgrp_time_from_event(event);
3877 perf_event_update_time(event);
3879 perf_event_update_sibling_time(event);
3881 if (event->state != PERF_EVENT_STATE_ACTIVE)
3890 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3894 for_each_sibling_event(sub, event) {
3895 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3897 * Use sibling's PMU rather than @event's since
3898 * sibling could be on different (eg: software) PMU.
3900 sub->pmu->read(sub);
3904 data->ret = pmu->commit_txn(pmu);
3907 raw_spin_unlock(&ctx->lock);
3910 static inline u64 perf_event_count(struct perf_event *event)
3912 return local64_read(&event->count) + atomic64_read(&event->child_count);
3916 * NMI-safe method to read a local event, that is an event that
3918 * - either for the current task, or for this CPU
3919 * - does not have inherit set, for inherited task events
3920 * will not be local and we cannot read them atomically
3921 * - must not have a pmu::count method
3923 int perf_event_read_local(struct perf_event *event, u64 *value,
3924 u64 *enabled, u64 *running)
3926 unsigned long flags;
3930 * Disabling interrupts avoids all counter scheduling (context
3931 * switches, timer based rotation and IPIs).
3933 local_irq_save(flags);
3936 * It must not be an event with inherit set, we cannot read
3937 * all child counters from atomic context.
3939 if (event->attr.inherit) {
3944 /* If this is a per-task event, it must be for current */
3945 if ((event->attach_state & PERF_ATTACH_TASK) &&
3946 event->hw.target != current) {
3951 /* If this is a per-CPU event, it must be for this CPU */
3952 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3953 event->cpu != smp_processor_id()) {
3958 /* If this is a pinned event it must be running on this CPU */
3959 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3965 * If the event is currently on this CPU, its either a per-task event,
3966 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3969 if (event->oncpu == smp_processor_id())
3970 event->pmu->read(event);
3972 *value = local64_read(&event->count);
3973 if (enabled || running) {
3974 u64 now = event->shadow_ctx_time + perf_clock();
3975 u64 __enabled, __running;
3977 __perf_update_times(event, now, &__enabled, &__running);
3979 *enabled = __enabled;
3981 *running = __running;
3984 local_irq_restore(flags);
3989 static int perf_event_read(struct perf_event *event, bool group)
3991 enum perf_event_state state = READ_ONCE(event->state);
3992 int event_cpu, ret = 0;
3995 * If event is enabled and currently active on a CPU, update the
3996 * value in the event structure:
3999 if (state == PERF_EVENT_STATE_ACTIVE) {
4000 struct perf_read_data data;
4003 * Orders the ->state and ->oncpu loads such that if we see
4004 * ACTIVE we must also see the right ->oncpu.
4006 * Matches the smp_wmb() from event_sched_in().
4010 event_cpu = READ_ONCE(event->oncpu);
4011 if ((unsigned)event_cpu >= nr_cpu_ids)
4014 data = (struct perf_read_data){
4021 event_cpu = __perf_event_read_cpu(event, event_cpu);
4024 * Purposely ignore the smp_call_function_single() return
4027 * If event_cpu isn't a valid CPU it means the event got
4028 * scheduled out and that will have updated the event count.
4030 * Therefore, either way, we'll have an up-to-date event count
4033 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4037 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4038 struct perf_event_context *ctx = event->ctx;
4039 unsigned long flags;
4041 raw_spin_lock_irqsave(&ctx->lock, flags);
4042 state = event->state;
4043 if (state != PERF_EVENT_STATE_INACTIVE) {
4044 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4049 * May read while context is not active (e.g., thread is
4050 * blocked), in that case we cannot update context time
4052 if (ctx->is_active & EVENT_TIME) {
4053 update_context_time(ctx);
4054 update_cgrp_time_from_event(event);
4057 perf_event_update_time(event);
4059 perf_event_update_sibling_time(event);
4060 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4067 * Initialize the perf_event context in a task_struct:
4069 static void __perf_event_init_context(struct perf_event_context *ctx)
4071 raw_spin_lock_init(&ctx->lock);
4072 mutex_init(&ctx->mutex);
4073 INIT_LIST_HEAD(&ctx->active_ctx_list);
4074 perf_event_groups_init(&ctx->pinned_groups);
4075 perf_event_groups_init(&ctx->flexible_groups);
4076 INIT_LIST_HEAD(&ctx->event_list);
4077 INIT_LIST_HEAD(&ctx->pinned_active);
4078 INIT_LIST_HEAD(&ctx->flexible_active);
4079 refcount_set(&ctx->refcount, 1);
4082 static struct perf_event_context *
4083 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4085 struct perf_event_context *ctx;
4087 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4091 __perf_event_init_context(ctx);
4093 ctx->task = get_task_struct(task);
4099 static struct task_struct *
4100 find_lively_task_by_vpid(pid_t vpid)
4102 struct task_struct *task;
4108 task = find_task_by_vpid(vpid);
4110 get_task_struct(task);
4114 return ERR_PTR(-ESRCH);
4120 * Returns a matching context with refcount and pincount.
4122 static struct perf_event_context *
4123 find_get_context(struct pmu *pmu, struct task_struct *task,
4124 struct perf_event *event)
4126 struct perf_event_context *ctx, *clone_ctx = NULL;
4127 struct perf_cpu_context *cpuctx;
4128 void *task_ctx_data = NULL;
4129 unsigned long flags;
4131 int cpu = event->cpu;
4134 /* Must be root to operate on a CPU event: */
4135 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4136 return ERR_PTR(-EACCES);
4138 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4147 ctxn = pmu->task_ctx_nr;
4151 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4152 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4153 if (!task_ctx_data) {
4160 ctx = perf_lock_task_context(task, ctxn, &flags);
4162 clone_ctx = unclone_ctx(ctx);
4165 if (task_ctx_data && !ctx->task_ctx_data) {
4166 ctx->task_ctx_data = task_ctx_data;
4167 task_ctx_data = NULL;
4169 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4174 ctx = alloc_perf_context(pmu, task);
4179 if (task_ctx_data) {
4180 ctx->task_ctx_data = task_ctx_data;
4181 task_ctx_data = NULL;
4185 mutex_lock(&task->perf_event_mutex);
4187 * If it has already passed perf_event_exit_task().
4188 * we must see PF_EXITING, it takes this mutex too.
4190 if (task->flags & PF_EXITING)
4192 else if (task->perf_event_ctxp[ctxn])
4197 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4199 mutex_unlock(&task->perf_event_mutex);
4201 if (unlikely(err)) {
4210 kfree(task_ctx_data);
4214 kfree(task_ctx_data);
4215 return ERR_PTR(err);
4218 static void perf_event_free_filter(struct perf_event *event);
4219 static void perf_event_free_bpf_prog(struct perf_event *event);
4221 static void free_event_rcu(struct rcu_head *head)
4223 struct perf_event *event;
4225 event = container_of(head, struct perf_event, rcu_head);
4227 put_pid_ns(event->ns);
4228 perf_event_free_filter(event);
4232 static void ring_buffer_attach(struct perf_event *event,
4233 struct ring_buffer *rb);
4235 static void detach_sb_event(struct perf_event *event)
4237 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4239 raw_spin_lock(&pel->lock);
4240 list_del_rcu(&event->sb_list);
4241 raw_spin_unlock(&pel->lock);
4244 static bool is_sb_event(struct perf_event *event)
4246 struct perf_event_attr *attr = &event->attr;
4251 if (event->attach_state & PERF_ATTACH_TASK)
4254 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4255 attr->comm || attr->comm_exec ||
4256 attr->task || attr->ksymbol ||
4257 attr->context_switch ||
4263 static void unaccount_pmu_sb_event(struct perf_event *event)
4265 if (is_sb_event(event))
4266 detach_sb_event(event);
4269 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4274 if (is_cgroup_event(event))
4275 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4278 #ifdef CONFIG_NO_HZ_FULL
4279 static DEFINE_SPINLOCK(nr_freq_lock);
4282 static void unaccount_freq_event_nohz(void)
4284 #ifdef CONFIG_NO_HZ_FULL
4285 spin_lock(&nr_freq_lock);
4286 if (atomic_dec_and_test(&nr_freq_events))
4287 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4288 spin_unlock(&nr_freq_lock);
4292 static void unaccount_freq_event(void)
4294 if (tick_nohz_full_enabled())
4295 unaccount_freq_event_nohz();
4297 atomic_dec(&nr_freq_events);
4300 static void unaccount_event(struct perf_event *event)
4307 if (event->attach_state & PERF_ATTACH_TASK)
4309 if (event->attr.mmap || event->attr.mmap_data)
4310 atomic_dec(&nr_mmap_events);
4311 if (event->attr.comm)
4312 atomic_dec(&nr_comm_events);
4313 if (event->attr.namespaces)
4314 atomic_dec(&nr_namespaces_events);
4315 if (event->attr.task)
4316 atomic_dec(&nr_task_events);
4317 if (event->attr.freq)
4318 unaccount_freq_event();
4319 if (event->attr.context_switch) {
4321 atomic_dec(&nr_switch_events);
4323 if (is_cgroup_event(event))
4325 if (has_branch_stack(event))
4327 if (event->attr.ksymbol)
4328 atomic_dec(&nr_ksymbol_events);
4329 if (event->attr.bpf_event)
4330 atomic_dec(&nr_bpf_events);
4333 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4334 schedule_delayed_work(&perf_sched_work, HZ);
4337 unaccount_event_cpu(event, event->cpu);
4339 unaccount_pmu_sb_event(event);
4342 static void perf_sched_delayed(struct work_struct *work)
4344 mutex_lock(&perf_sched_mutex);
4345 if (atomic_dec_and_test(&perf_sched_count))
4346 static_branch_disable(&perf_sched_events);
4347 mutex_unlock(&perf_sched_mutex);
4351 * The following implement mutual exclusion of events on "exclusive" pmus
4352 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4353 * at a time, so we disallow creating events that might conflict, namely:
4355 * 1) cpu-wide events in the presence of per-task events,
4356 * 2) per-task events in the presence of cpu-wide events,
4357 * 3) two matching events on the same context.
4359 * The former two cases are handled in the allocation path (perf_event_alloc(),
4360 * _free_event()), the latter -- before the first perf_install_in_context().
4362 static int exclusive_event_init(struct perf_event *event)
4364 struct pmu *pmu = event->pmu;
4366 if (!is_exclusive_pmu(pmu))
4370 * Prevent co-existence of per-task and cpu-wide events on the
4371 * same exclusive pmu.
4373 * Negative pmu::exclusive_cnt means there are cpu-wide
4374 * events on this "exclusive" pmu, positive means there are
4377 * Since this is called in perf_event_alloc() path, event::ctx
4378 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4379 * to mean "per-task event", because unlike other attach states it
4380 * never gets cleared.
4382 if (event->attach_state & PERF_ATTACH_TASK) {
4383 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4386 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4393 static void exclusive_event_destroy(struct perf_event *event)
4395 struct pmu *pmu = event->pmu;
4397 if (!is_exclusive_pmu(pmu))
4400 /* see comment in exclusive_event_init() */
4401 if (event->attach_state & PERF_ATTACH_TASK)
4402 atomic_dec(&pmu->exclusive_cnt);
4404 atomic_inc(&pmu->exclusive_cnt);
4407 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4409 if ((e1->pmu == e2->pmu) &&
4410 (e1->cpu == e2->cpu ||
4417 static bool exclusive_event_installable(struct perf_event *event,
4418 struct perf_event_context *ctx)
4420 struct perf_event *iter_event;
4421 struct pmu *pmu = event->pmu;
4423 lockdep_assert_held(&ctx->mutex);
4425 if (!is_exclusive_pmu(pmu))
4428 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4429 if (exclusive_event_match(iter_event, event))
4436 static void perf_addr_filters_splice(struct perf_event *event,
4437 struct list_head *head);
4439 static void _free_event(struct perf_event *event)
4441 irq_work_sync(&event->pending);
4443 unaccount_event(event);
4447 * Can happen when we close an event with re-directed output.
4449 * Since we have a 0 refcount, perf_mmap_close() will skip
4450 * over us; possibly making our ring_buffer_put() the last.
4452 mutex_lock(&event->mmap_mutex);
4453 ring_buffer_attach(event, NULL);
4454 mutex_unlock(&event->mmap_mutex);
4457 if (is_cgroup_event(event))
4458 perf_detach_cgroup(event);
4460 if (!event->parent) {
4461 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4462 put_callchain_buffers();
4465 perf_event_free_bpf_prog(event);
4466 perf_addr_filters_splice(event, NULL);
4467 kfree(event->addr_filter_ranges);
4470 event->destroy(event);
4473 * Must be after ->destroy(), due to uprobe_perf_close() using
4476 if (event->hw.target)
4477 put_task_struct(event->hw.target);
4480 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4481 * all task references must be cleaned up.
4484 put_ctx(event->ctx);
4486 exclusive_event_destroy(event);
4487 module_put(event->pmu->module);
4489 call_rcu(&event->rcu_head, free_event_rcu);
4493 * Used to free events which have a known refcount of 1, such as in error paths
4494 * where the event isn't exposed yet and inherited events.
4496 static void free_event(struct perf_event *event)
4498 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4499 "unexpected event refcount: %ld; ptr=%p\n",
4500 atomic_long_read(&event->refcount), event)) {
4501 /* leak to avoid use-after-free */
4509 * Remove user event from the owner task.
4511 static void perf_remove_from_owner(struct perf_event *event)
4513 struct task_struct *owner;
4517 * Matches the smp_store_release() in perf_event_exit_task(). If we
4518 * observe !owner it means the list deletion is complete and we can
4519 * indeed free this event, otherwise we need to serialize on
4520 * owner->perf_event_mutex.
4522 owner = READ_ONCE(event->owner);
4525 * Since delayed_put_task_struct() also drops the last
4526 * task reference we can safely take a new reference
4527 * while holding the rcu_read_lock().
4529 get_task_struct(owner);
4535 * If we're here through perf_event_exit_task() we're already
4536 * holding ctx->mutex which would be an inversion wrt. the
4537 * normal lock order.
4539 * However we can safely take this lock because its the child
4542 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4545 * We have to re-check the event->owner field, if it is cleared
4546 * we raced with perf_event_exit_task(), acquiring the mutex
4547 * ensured they're done, and we can proceed with freeing the
4551 list_del_init(&event->owner_entry);
4552 smp_store_release(&event->owner, NULL);
4554 mutex_unlock(&owner->perf_event_mutex);
4555 put_task_struct(owner);
4559 static void put_event(struct perf_event *event)
4561 if (!atomic_long_dec_and_test(&event->refcount))
4568 * Kill an event dead; while event:refcount will preserve the event
4569 * object, it will not preserve its functionality. Once the last 'user'
4570 * gives up the object, we'll destroy the thing.
4572 int perf_event_release_kernel(struct perf_event *event)
4574 struct perf_event_context *ctx = event->ctx;
4575 struct perf_event *child, *tmp;
4576 LIST_HEAD(free_list);
4579 * If we got here through err_file: fput(event_file); we will not have
4580 * attached to a context yet.
4583 WARN_ON_ONCE(event->attach_state &
4584 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4588 if (!is_kernel_event(event))
4589 perf_remove_from_owner(event);
4591 ctx = perf_event_ctx_lock(event);
4592 WARN_ON_ONCE(ctx->parent_ctx);
4593 perf_remove_from_context(event, DETACH_GROUP);
4595 raw_spin_lock_irq(&ctx->lock);
4597 * Mark this event as STATE_DEAD, there is no external reference to it
4600 * Anybody acquiring event->child_mutex after the below loop _must_
4601 * also see this, most importantly inherit_event() which will avoid
4602 * placing more children on the list.
4604 * Thus this guarantees that we will in fact observe and kill _ALL_
4607 event->state = PERF_EVENT_STATE_DEAD;
4608 raw_spin_unlock_irq(&ctx->lock);
4610 perf_event_ctx_unlock(event, ctx);
4613 mutex_lock(&event->child_mutex);
4614 list_for_each_entry(child, &event->child_list, child_list) {
4617 * Cannot change, child events are not migrated, see the
4618 * comment with perf_event_ctx_lock_nested().
4620 ctx = READ_ONCE(child->ctx);
4622 * Since child_mutex nests inside ctx::mutex, we must jump
4623 * through hoops. We start by grabbing a reference on the ctx.
4625 * Since the event cannot get freed while we hold the
4626 * child_mutex, the context must also exist and have a !0
4632 * Now that we have a ctx ref, we can drop child_mutex, and
4633 * acquire ctx::mutex without fear of it going away. Then we
4634 * can re-acquire child_mutex.
4636 mutex_unlock(&event->child_mutex);
4637 mutex_lock(&ctx->mutex);
4638 mutex_lock(&event->child_mutex);
4641 * Now that we hold ctx::mutex and child_mutex, revalidate our
4642 * state, if child is still the first entry, it didn't get freed
4643 * and we can continue doing so.
4645 tmp = list_first_entry_or_null(&event->child_list,
4646 struct perf_event, child_list);
4648 perf_remove_from_context(child, DETACH_GROUP);
4649 list_move(&child->child_list, &free_list);
4651 * This matches the refcount bump in inherit_event();
4652 * this can't be the last reference.
4657 mutex_unlock(&event->child_mutex);
4658 mutex_unlock(&ctx->mutex);
4662 mutex_unlock(&event->child_mutex);
4664 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4665 void *var = &child->ctx->refcount;
4667 list_del(&child->child_list);
4671 * Wake any perf_event_free_task() waiting for this event to be
4674 smp_mb(); /* pairs with wait_var_event() */
4679 put_event(event); /* Must be the 'last' reference */
4682 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4685 * Called when the last reference to the file is gone.
4687 static int perf_release(struct inode *inode, struct file *file)
4689 perf_event_release_kernel(file->private_data);
4693 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4695 struct perf_event *child;
4701 mutex_lock(&event->child_mutex);
4703 (void)perf_event_read(event, false);
4704 total += perf_event_count(event);
4706 *enabled += event->total_time_enabled +
4707 atomic64_read(&event->child_total_time_enabled);
4708 *running += event->total_time_running +
4709 atomic64_read(&event->child_total_time_running);
4711 list_for_each_entry(child, &event->child_list, child_list) {
4712 (void)perf_event_read(child, false);
4713 total += perf_event_count(child);
4714 *enabled += child->total_time_enabled;
4715 *running += child->total_time_running;
4717 mutex_unlock(&event->child_mutex);
4722 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4724 struct perf_event_context *ctx;
4727 ctx = perf_event_ctx_lock(event);
4728 count = __perf_event_read_value(event, enabled, running);
4729 perf_event_ctx_unlock(event, ctx);
4733 EXPORT_SYMBOL_GPL(perf_event_read_value);
4735 static int __perf_read_group_add(struct perf_event *leader,
4736 u64 read_format, u64 *values)
4738 struct perf_event_context *ctx = leader->ctx;
4739 struct perf_event *sub;
4740 unsigned long flags;
4741 int n = 1; /* skip @nr */
4744 ret = perf_event_read(leader, true);
4748 raw_spin_lock_irqsave(&ctx->lock, flags);
4751 * Since we co-schedule groups, {enabled,running} times of siblings
4752 * will be identical to those of the leader, so we only publish one
4755 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4756 values[n++] += leader->total_time_enabled +
4757 atomic64_read(&leader->child_total_time_enabled);
4760 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4761 values[n++] += leader->total_time_running +
4762 atomic64_read(&leader->child_total_time_running);
4766 * Write {count,id} tuples for every sibling.
4768 values[n++] += perf_event_count(leader);
4769 if (read_format & PERF_FORMAT_ID)
4770 values[n++] = primary_event_id(leader);
4772 for_each_sibling_event(sub, leader) {
4773 values[n++] += perf_event_count(sub);
4774 if (read_format & PERF_FORMAT_ID)
4775 values[n++] = primary_event_id(sub);
4778 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4782 static int perf_read_group(struct perf_event *event,
4783 u64 read_format, char __user *buf)
4785 struct perf_event *leader = event->group_leader, *child;
4786 struct perf_event_context *ctx = leader->ctx;
4790 lockdep_assert_held(&ctx->mutex);
4792 values = kzalloc(event->read_size, GFP_KERNEL);
4796 values[0] = 1 + leader->nr_siblings;
4799 * By locking the child_mutex of the leader we effectively
4800 * lock the child list of all siblings.. XXX explain how.
4802 mutex_lock(&leader->child_mutex);
4804 ret = __perf_read_group_add(leader, read_format, values);
4808 list_for_each_entry(child, &leader->child_list, child_list) {
4809 ret = __perf_read_group_add(child, read_format, values);
4814 mutex_unlock(&leader->child_mutex);
4816 ret = event->read_size;
4817 if (copy_to_user(buf, values, event->read_size))
4822 mutex_unlock(&leader->child_mutex);
4828 static int perf_read_one(struct perf_event *event,
4829 u64 read_format, char __user *buf)
4831 u64 enabled, running;
4835 values[n++] = __perf_event_read_value(event, &enabled, &running);
4836 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4837 values[n++] = enabled;
4838 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4839 values[n++] = running;
4840 if (read_format & PERF_FORMAT_ID)
4841 values[n++] = primary_event_id(event);
4843 if (copy_to_user(buf, values, n * sizeof(u64)))
4846 return n * sizeof(u64);
4849 static bool is_event_hup(struct perf_event *event)
4853 if (event->state > PERF_EVENT_STATE_EXIT)
4856 mutex_lock(&event->child_mutex);
4857 no_children = list_empty(&event->child_list);
4858 mutex_unlock(&event->child_mutex);
4863 * Read the performance event - simple non blocking version for now
4866 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4868 u64 read_format = event->attr.read_format;
4872 * Return end-of-file for a read on an event that is in
4873 * error state (i.e. because it was pinned but it couldn't be
4874 * scheduled on to the CPU at some point).
4876 if (event->state == PERF_EVENT_STATE_ERROR)
4879 if (count < event->read_size)
4882 WARN_ON_ONCE(event->ctx->parent_ctx);
4883 if (read_format & PERF_FORMAT_GROUP)
4884 ret = perf_read_group(event, read_format, buf);
4886 ret = perf_read_one(event, read_format, buf);
4892 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4894 struct perf_event *event = file->private_data;
4895 struct perf_event_context *ctx;
4898 ctx = perf_event_ctx_lock(event);
4899 ret = __perf_read(event, buf, count);
4900 perf_event_ctx_unlock(event, ctx);
4905 static __poll_t perf_poll(struct file *file, poll_table *wait)
4907 struct perf_event *event = file->private_data;
4908 struct ring_buffer *rb;
4909 __poll_t events = EPOLLHUP;
4911 poll_wait(file, &event->waitq, wait);
4913 if (is_event_hup(event))
4917 * Pin the event->rb by taking event->mmap_mutex; otherwise
4918 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4920 mutex_lock(&event->mmap_mutex);
4923 events = atomic_xchg(&rb->poll, 0);
4924 mutex_unlock(&event->mmap_mutex);
4928 static void _perf_event_reset(struct perf_event *event)
4930 (void)perf_event_read(event, false);
4931 local64_set(&event->count, 0);
4932 perf_event_update_userpage(event);
4936 * Holding the top-level event's child_mutex means that any
4937 * descendant process that has inherited this event will block
4938 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4939 * task existence requirements of perf_event_enable/disable.
4941 static void perf_event_for_each_child(struct perf_event *event,
4942 void (*func)(struct perf_event *))
4944 struct perf_event *child;
4946 WARN_ON_ONCE(event->ctx->parent_ctx);
4948 mutex_lock(&event->child_mutex);
4950 list_for_each_entry(child, &event->child_list, child_list)
4952 mutex_unlock(&event->child_mutex);
4955 static void perf_event_for_each(struct perf_event *event,
4956 void (*func)(struct perf_event *))
4958 struct perf_event_context *ctx = event->ctx;
4959 struct perf_event *sibling;
4961 lockdep_assert_held(&ctx->mutex);
4963 event = event->group_leader;
4965 perf_event_for_each_child(event, func);
4966 for_each_sibling_event(sibling, event)
4967 perf_event_for_each_child(sibling, func);
4970 static void __perf_event_period(struct perf_event *event,
4971 struct perf_cpu_context *cpuctx,
4972 struct perf_event_context *ctx,
4975 u64 value = *((u64 *)info);
4978 if (event->attr.freq) {
4979 event->attr.sample_freq = value;
4981 event->attr.sample_period = value;
4982 event->hw.sample_period = value;
4985 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4987 perf_pmu_disable(ctx->pmu);
4989 * We could be throttled; unthrottle now to avoid the tick
4990 * trying to unthrottle while we already re-started the event.
4992 if (event->hw.interrupts == MAX_INTERRUPTS) {
4993 event->hw.interrupts = 0;
4994 perf_log_throttle(event, 1);
4996 event->pmu->stop(event, PERF_EF_UPDATE);
4999 local64_set(&event->hw.period_left, 0);
5002 event->pmu->start(event, PERF_EF_RELOAD);
5003 perf_pmu_enable(ctx->pmu);
5007 static int perf_event_check_period(struct perf_event *event, u64 value)
5009 return event->pmu->check_period(event, value);
5012 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5016 if (!is_sampling_event(event))
5019 if (copy_from_user(&value, arg, sizeof(value)))
5025 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5028 if (perf_event_check_period(event, value))
5031 if (!event->attr.freq && (value & (1ULL << 63)))
5034 event_function_call(event, __perf_event_period, &value);
5039 static const struct file_operations perf_fops;
5041 static inline int perf_fget_light(int fd, struct fd *p)
5043 struct fd f = fdget(fd);
5047 if (f.file->f_op != &perf_fops) {
5055 static int perf_event_set_output(struct perf_event *event,
5056 struct perf_event *output_event);
5057 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5058 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5059 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5060 struct perf_event_attr *attr);
5062 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5064 void (*func)(struct perf_event *);
5068 case PERF_EVENT_IOC_ENABLE:
5069 func = _perf_event_enable;
5071 case PERF_EVENT_IOC_DISABLE:
5072 func = _perf_event_disable;
5074 case PERF_EVENT_IOC_RESET:
5075 func = _perf_event_reset;
5078 case PERF_EVENT_IOC_REFRESH:
5079 return _perf_event_refresh(event, arg);
5081 case PERF_EVENT_IOC_PERIOD:
5082 return perf_event_period(event, (u64 __user *)arg);
5084 case PERF_EVENT_IOC_ID:
5086 u64 id = primary_event_id(event);
5088 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5093 case PERF_EVENT_IOC_SET_OUTPUT:
5097 struct perf_event *output_event;
5099 ret = perf_fget_light(arg, &output);
5102 output_event = output.file->private_data;
5103 ret = perf_event_set_output(event, output_event);
5106 ret = perf_event_set_output(event, NULL);
5111 case PERF_EVENT_IOC_SET_FILTER:
5112 return perf_event_set_filter(event, (void __user *)arg);
5114 case PERF_EVENT_IOC_SET_BPF:
5115 return perf_event_set_bpf_prog(event, arg);
5117 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5118 struct ring_buffer *rb;
5121 rb = rcu_dereference(event->rb);
5122 if (!rb || !rb->nr_pages) {
5126 rb_toggle_paused(rb, !!arg);
5131 case PERF_EVENT_IOC_QUERY_BPF:
5132 return perf_event_query_prog_array(event, (void __user *)arg);
5134 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5135 struct perf_event_attr new_attr;
5136 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5142 return perf_event_modify_attr(event, &new_attr);
5148 if (flags & PERF_IOC_FLAG_GROUP)
5149 perf_event_for_each(event, func);
5151 perf_event_for_each_child(event, func);
5156 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5158 struct perf_event *event = file->private_data;
5159 struct perf_event_context *ctx;
5162 ctx = perf_event_ctx_lock(event);
5163 ret = _perf_ioctl(event, cmd, arg);
5164 perf_event_ctx_unlock(event, ctx);
5169 #ifdef CONFIG_COMPAT
5170 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5173 switch (_IOC_NR(cmd)) {
5174 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5175 case _IOC_NR(PERF_EVENT_IOC_ID):
5176 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5177 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5178 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5179 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5180 cmd &= ~IOCSIZE_MASK;
5181 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5185 return perf_ioctl(file, cmd, arg);
5188 # define perf_compat_ioctl NULL
5191 int perf_event_task_enable(void)
5193 struct perf_event_context *ctx;
5194 struct perf_event *event;
5196 mutex_lock(¤t->perf_event_mutex);
5197 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5198 ctx = perf_event_ctx_lock(event);
5199 perf_event_for_each_child(event, _perf_event_enable);
5200 perf_event_ctx_unlock(event, ctx);
5202 mutex_unlock(¤t->perf_event_mutex);
5207 int perf_event_task_disable(void)
5209 struct perf_event_context *ctx;
5210 struct perf_event *event;
5212 mutex_lock(¤t->perf_event_mutex);
5213 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5214 ctx = perf_event_ctx_lock(event);
5215 perf_event_for_each_child(event, _perf_event_disable);
5216 perf_event_ctx_unlock(event, ctx);
5218 mutex_unlock(¤t->perf_event_mutex);
5223 static int perf_event_index(struct perf_event *event)
5225 if (event->hw.state & PERF_HES_STOPPED)
5228 if (event->state != PERF_EVENT_STATE_ACTIVE)
5231 return event->pmu->event_idx(event);
5234 static void calc_timer_values(struct perf_event *event,
5241 *now = perf_clock();
5242 ctx_time = event->shadow_ctx_time + *now;
5243 __perf_update_times(event, ctx_time, enabled, running);
5246 static void perf_event_init_userpage(struct perf_event *event)
5248 struct perf_event_mmap_page *userpg;
5249 struct ring_buffer *rb;
5252 rb = rcu_dereference(event->rb);
5256 userpg = rb->user_page;
5258 /* Allow new userspace to detect that bit 0 is deprecated */
5259 userpg->cap_bit0_is_deprecated = 1;
5260 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5261 userpg->data_offset = PAGE_SIZE;
5262 userpg->data_size = perf_data_size(rb);
5268 void __weak arch_perf_update_userpage(
5269 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5274 * Callers need to ensure there can be no nesting of this function, otherwise
5275 * the seqlock logic goes bad. We can not serialize this because the arch
5276 * code calls this from NMI context.
5278 void perf_event_update_userpage(struct perf_event *event)
5280 struct perf_event_mmap_page *userpg;
5281 struct ring_buffer *rb;
5282 u64 enabled, running, now;
5285 rb = rcu_dereference(event->rb);
5290 * compute total_time_enabled, total_time_running
5291 * based on snapshot values taken when the event
5292 * was last scheduled in.
5294 * we cannot simply called update_context_time()
5295 * because of locking issue as we can be called in
5298 calc_timer_values(event, &now, &enabled, &running);
5300 userpg = rb->user_page;
5302 * Disable preemption to guarantee consistent time stamps are stored to
5308 userpg->index = perf_event_index(event);
5309 userpg->offset = perf_event_count(event);
5311 userpg->offset -= local64_read(&event->hw.prev_count);
5313 userpg->time_enabled = enabled +
5314 atomic64_read(&event->child_total_time_enabled);
5316 userpg->time_running = running +
5317 atomic64_read(&event->child_total_time_running);
5319 arch_perf_update_userpage(event, userpg, now);
5327 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5329 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5331 struct perf_event *event = vmf->vma->vm_file->private_data;
5332 struct ring_buffer *rb;
5333 vm_fault_t ret = VM_FAULT_SIGBUS;
5335 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5336 if (vmf->pgoff == 0)
5342 rb = rcu_dereference(event->rb);
5346 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5349 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5353 get_page(vmf->page);
5354 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5355 vmf->page->index = vmf->pgoff;
5364 static void ring_buffer_attach(struct perf_event *event,
5365 struct ring_buffer *rb)
5367 struct ring_buffer *old_rb = NULL;
5368 unsigned long flags;
5372 * Should be impossible, we set this when removing
5373 * event->rb_entry and wait/clear when adding event->rb_entry.
5375 WARN_ON_ONCE(event->rcu_pending);
5378 spin_lock_irqsave(&old_rb->event_lock, flags);
5379 list_del_rcu(&event->rb_entry);
5380 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5382 event->rcu_batches = get_state_synchronize_rcu();
5383 event->rcu_pending = 1;
5387 if (event->rcu_pending) {
5388 cond_synchronize_rcu(event->rcu_batches);
5389 event->rcu_pending = 0;
5392 spin_lock_irqsave(&rb->event_lock, flags);
5393 list_add_rcu(&event->rb_entry, &rb->event_list);
5394 spin_unlock_irqrestore(&rb->event_lock, flags);
5398 * Avoid racing with perf_mmap_close(AUX): stop the event
5399 * before swizzling the event::rb pointer; if it's getting
5400 * unmapped, its aux_mmap_count will be 0 and it won't
5401 * restart. See the comment in __perf_pmu_output_stop().
5403 * Data will inevitably be lost when set_output is done in
5404 * mid-air, but then again, whoever does it like this is
5405 * not in for the data anyway.
5408 perf_event_stop(event, 0);
5410 rcu_assign_pointer(event->rb, rb);
5413 ring_buffer_put(old_rb);
5415 * Since we detached before setting the new rb, so that we
5416 * could attach the new rb, we could have missed a wakeup.
5419 wake_up_all(&event->waitq);
5423 static void ring_buffer_wakeup(struct perf_event *event)
5425 struct ring_buffer *rb;
5428 rb = rcu_dereference(event->rb);
5430 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5431 wake_up_all(&event->waitq);
5436 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5438 struct ring_buffer *rb;
5441 rb = rcu_dereference(event->rb);
5443 if (!refcount_inc_not_zero(&rb->refcount))
5451 void ring_buffer_put(struct ring_buffer *rb)
5453 if (!refcount_dec_and_test(&rb->refcount))
5456 WARN_ON_ONCE(!list_empty(&rb->event_list));
5458 call_rcu(&rb->rcu_head, rb_free_rcu);
5461 static void perf_mmap_open(struct vm_area_struct *vma)
5463 struct perf_event *event = vma->vm_file->private_data;
5465 atomic_inc(&event->mmap_count);
5466 atomic_inc(&event->rb->mmap_count);
5469 atomic_inc(&event->rb->aux_mmap_count);
5471 if (event->pmu->event_mapped)
5472 event->pmu->event_mapped(event, vma->vm_mm);
5475 static void perf_pmu_output_stop(struct perf_event *event);
5478 * A buffer can be mmap()ed multiple times; either directly through the same
5479 * event, or through other events by use of perf_event_set_output().
5481 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5482 * the buffer here, where we still have a VM context. This means we need
5483 * to detach all events redirecting to us.
5485 static void perf_mmap_close(struct vm_area_struct *vma)
5487 struct perf_event *event = vma->vm_file->private_data;
5489 struct ring_buffer *rb = ring_buffer_get(event);
5490 struct user_struct *mmap_user = rb->mmap_user;
5491 int mmap_locked = rb->mmap_locked;
5492 unsigned long size = perf_data_size(rb);
5494 if (event->pmu->event_unmapped)
5495 event->pmu->event_unmapped(event, vma->vm_mm);
5498 * rb->aux_mmap_count will always drop before rb->mmap_count and
5499 * event->mmap_count, so it is ok to use event->mmap_mutex to
5500 * serialize with perf_mmap here.
5502 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5503 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5505 * Stop all AUX events that are writing to this buffer,
5506 * so that we can free its AUX pages and corresponding PMU
5507 * data. Note that after rb::aux_mmap_count dropped to zero,
5508 * they won't start any more (see perf_aux_output_begin()).
5510 perf_pmu_output_stop(event);
5512 /* now it's safe to free the pages */
5513 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5514 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5516 /* this has to be the last one */
5518 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5520 mutex_unlock(&event->mmap_mutex);
5523 atomic_dec(&rb->mmap_count);
5525 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5528 ring_buffer_attach(event, NULL);
5529 mutex_unlock(&event->mmap_mutex);
5531 /* If there's still other mmap()s of this buffer, we're done. */
5532 if (atomic_read(&rb->mmap_count))
5536 * No other mmap()s, detach from all other events that might redirect
5537 * into the now unreachable buffer. Somewhat complicated by the
5538 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5542 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5543 if (!atomic_long_inc_not_zero(&event->refcount)) {
5545 * This event is en-route to free_event() which will
5546 * detach it and remove it from the list.
5552 mutex_lock(&event->mmap_mutex);
5554 * Check we didn't race with perf_event_set_output() which can
5555 * swizzle the rb from under us while we were waiting to
5556 * acquire mmap_mutex.
5558 * If we find a different rb; ignore this event, a next
5559 * iteration will no longer find it on the list. We have to
5560 * still restart the iteration to make sure we're not now
5561 * iterating the wrong list.
5563 if (event->rb == rb)
5564 ring_buffer_attach(event, NULL);
5566 mutex_unlock(&event->mmap_mutex);
5570 * Restart the iteration; either we're on the wrong list or
5571 * destroyed its integrity by doing a deletion.
5578 * It could be there's still a few 0-ref events on the list; they'll
5579 * get cleaned up by free_event() -- they'll also still have their
5580 * ref on the rb and will free it whenever they are done with it.
5582 * Aside from that, this buffer is 'fully' detached and unmapped,
5583 * undo the VM accounting.
5586 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5587 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5588 free_uid(mmap_user);
5591 ring_buffer_put(rb); /* could be last */
5594 static const struct vm_operations_struct perf_mmap_vmops = {
5595 .open = perf_mmap_open,
5596 .close = perf_mmap_close, /* non mergeable */
5597 .fault = perf_mmap_fault,
5598 .page_mkwrite = perf_mmap_fault,
5601 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5603 struct perf_event *event = file->private_data;
5604 unsigned long user_locked, user_lock_limit;
5605 struct user_struct *user = current_user();
5606 unsigned long locked, lock_limit;
5607 struct ring_buffer *rb = NULL;
5608 unsigned long vma_size;
5609 unsigned long nr_pages;
5610 long user_extra = 0, extra = 0;
5611 int ret = 0, flags = 0;
5614 * Don't allow mmap() of inherited per-task counters. This would
5615 * create a performance issue due to all children writing to the
5618 if (event->cpu == -1 && event->attr.inherit)
5621 if (!(vma->vm_flags & VM_SHARED))
5624 vma_size = vma->vm_end - vma->vm_start;
5626 if (vma->vm_pgoff == 0) {
5627 nr_pages = (vma_size / PAGE_SIZE) - 1;
5630 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5631 * mapped, all subsequent mappings should have the same size
5632 * and offset. Must be above the normal perf buffer.
5634 u64 aux_offset, aux_size;
5639 nr_pages = vma_size / PAGE_SIZE;
5641 mutex_lock(&event->mmap_mutex);
5648 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5649 aux_size = READ_ONCE(rb->user_page->aux_size);
5651 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5654 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5657 /* already mapped with a different offset */
5658 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5661 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5664 /* already mapped with a different size */
5665 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5668 if (!is_power_of_2(nr_pages))
5671 if (!atomic_inc_not_zero(&rb->mmap_count))
5674 if (rb_has_aux(rb)) {
5675 atomic_inc(&rb->aux_mmap_count);
5680 atomic_set(&rb->aux_mmap_count, 1);
5681 user_extra = nr_pages;
5687 * If we have rb pages ensure they're a power-of-two number, so we
5688 * can do bitmasks instead of modulo.
5690 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5693 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5696 WARN_ON_ONCE(event->ctx->parent_ctx);
5698 mutex_lock(&event->mmap_mutex);
5700 if (event->rb->nr_pages != nr_pages) {
5705 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5707 * Raced against perf_mmap_close() through
5708 * perf_event_set_output(). Try again, hope for better
5711 mutex_unlock(&event->mmap_mutex);
5718 user_extra = nr_pages + 1;
5721 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5724 * Increase the limit linearly with more CPUs:
5726 user_lock_limit *= num_online_cpus();
5728 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5730 if (user_locked > user_lock_limit)
5731 extra = user_locked - user_lock_limit;
5733 lock_limit = rlimit(RLIMIT_MEMLOCK);
5734 lock_limit >>= PAGE_SHIFT;
5735 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5737 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5738 !capable(CAP_IPC_LOCK)) {
5743 WARN_ON(!rb && event->rb);
5745 if (vma->vm_flags & VM_WRITE)
5746 flags |= RING_BUFFER_WRITABLE;
5749 rb = rb_alloc(nr_pages,
5750 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5758 atomic_set(&rb->mmap_count, 1);
5759 rb->mmap_user = get_current_user();
5760 rb->mmap_locked = extra;
5762 ring_buffer_attach(event, rb);
5764 perf_event_init_userpage(event);
5765 perf_event_update_userpage(event);
5767 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5768 event->attr.aux_watermark, flags);
5770 rb->aux_mmap_locked = extra;
5775 atomic_long_add(user_extra, &user->locked_vm);
5776 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5778 atomic_inc(&event->mmap_count);
5780 atomic_dec(&rb->mmap_count);
5783 mutex_unlock(&event->mmap_mutex);
5786 * Since pinned accounting is per vm we cannot allow fork() to copy our
5789 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5790 vma->vm_ops = &perf_mmap_vmops;
5792 if (event->pmu->event_mapped)
5793 event->pmu->event_mapped(event, vma->vm_mm);
5798 static int perf_fasync(int fd, struct file *filp, int on)
5800 struct inode *inode = file_inode(filp);
5801 struct perf_event *event = filp->private_data;
5805 retval = fasync_helper(fd, filp, on, &event->fasync);
5806 inode_unlock(inode);
5814 static const struct file_operations perf_fops = {
5815 .llseek = no_llseek,
5816 .release = perf_release,
5819 .unlocked_ioctl = perf_ioctl,
5820 .compat_ioctl = perf_compat_ioctl,
5822 .fasync = perf_fasync,
5828 * If there's data, ensure we set the poll() state and publish everything
5829 * to user-space before waking everybody up.
5832 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5834 /* only the parent has fasync state */
5836 event = event->parent;
5837 return &event->fasync;
5840 void perf_event_wakeup(struct perf_event *event)
5842 ring_buffer_wakeup(event);
5844 if (event->pending_kill) {
5845 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5846 event->pending_kill = 0;
5850 static void perf_pending_event_disable(struct perf_event *event)
5852 int cpu = READ_ONCE(event->pending_disable);
5857 if (cpu == smp_processor_id()) {
5858 WRITE_ONCE(event->pending_disable, -1);
5859 perf_event_disable_local(event);
5866 * perf_event_disable_inatomic()
5867 * @pending_disable = CPU-A;
5871 * @pending_disable = -1;
5874 * perf_event_disable_inatomic()
5875 * @pending_disable = CPU-B;
5876 * irq_work_queue(); // FAILS
5879 * perf_pending_event()
5881 * But the event runs on CPU-B and wants disabling there.
5883 irq_work_queue_on(&event->pending, cpu);
5886 static void perf_pending_event(struct irq_work *entry)
5888 struct perf_event *event = container_of(entry, struct perf_event, pending);
5891 rctx = perf_swevent_get_recursion_context();
5893 * If we 'fail' here, that's OK, it means recursion is already disabled
5894 * and we won't recurse 'further'.
5897 perf_pending_event_disable(event);
5899 if (event->pending_wakeup) {
5900 event->pending_wakeup = 0;
5901 perf_event_wakeup(event);
5905 perf_swevent_put_recursion_context(rctx);
5909 * We assume there is only KVM supporting the callbacks.
5910 * Later on, we might change it to a list if there is
5911 * another virtualization implementation supporting the callbacks.
5913 struct perf_guest_info_callbacks *perf_guest_cbs;
5915 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5917 perf_guest_cbs = cbs;
5920 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5922 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5924 perf_guest_cbs = NULL;
5927 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5930 perf_output_sample_regs(struct perf_output_handle *handle,
5931 struct pt_regs *regs, u64 mask)
5934 DECLARE_BITMAP(_mask, 64);
5936 bitmap_from_u64(_mask, mask);
5937 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5940 val = perf_reg_value(regs, bit);
5941 perf_output_put(handle, val);
5945 static void perf_sample_regs_user(struct perf_regs *regs_user,
5946 struct pt_regs *regs,
5947 struct pt_regs *regs_user_copy)
5949 if (user_mode(regs)) {
5950 regs_user->abi = perf_reg_abi(current);
5951 regs_user->regs = regs;
5952 } else if (!(current->flags & PF_KTHREAD)) {
5953 perf_get_regs_user(regs_user, regs, regs_user_copy);
5955 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5956 regs_user->regs = NULL;
5960 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5961 struct pt_regs *regs)
5963 regs_intr->regs = regs;
5964 regs_intr->abi = perf_reg_abi(current);
5969 * Get remaining task size from user stack pointer.
5971 * It'd be better to take stack vma map and limit this more
5972 * precisly, but there's no way to get it safely under interrupt,
5973 * so using TASK_SIZE as limit.
5975 static u64 perf_ustack_task_size(struct pt_regs *regs)
5977 unsigned long addr = perf_user_stack_pointer(regs);
5979 if (!addr || addr >= TASK_SIZE)
5982 return TASK_SIZE - addr;
5986 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5987 struct pt_regs *regs)
5991 /* No regs, no stack pointer, no dump. */
5996 * Check if we fit in with the requested stack size into the:
5998 * If we don't, we limit the size to the TASK_SIZE.
6000 * - remaining sample size
6001 * If we don't, we customize the stack size to
6002 * fit in to the remaining sample size.
6005 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6006 stack_size = min(stack_size, (u16) task_size);
6008 /* Current header size plus static size and dynamic size. */
6009 header_size += 2 * sizeof(u64);
6011 /* Do we fit in with the current stack dump size? */
6012 if ((u16) (header_size + stack_size) < header_size) {
6014 * If we overflow the maximum size for the sample,
6015 * we customize the stack dump size to fit in.
6017 stack_size = USHRT_MAX - header_size - sizeof(u64);
6018 stack_size = round_up(stack_size, sizeof(u64));
6025 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6026 struct pt_regs *regs)
6028 /* Case of a kernel thread, nothing to dump */
6031 perf_output_put(handle, size);
6041 * - the size requested by user or the best one we can fit
6042 * in to the sample max size
6044 * - user stack dump data
6046 * - the actual dumped size
6050 perf_output_put(handle, dump_size);
6053 sp = perf_user_stack_pointer(regs);
6056 rem = __output_copy_user(handle, (void *) sp, dump_size);
6058 dyn_size = dump_size - rem;
6060 perf_output_skip(handle, rem);
6063 perf_output_put(handle, dyn_size);
6067 static void __perf_event_header__init_id(struct perf_event_header *header,
6068 struct perf_sample_data *data,
6069 struct perf_event *event)
6071 u64 sample_type = event->attr.sample_type;
6073 data->type = sample_type;
6074 header->size += event->id_header_size;
6076 if (sample_type & PERF_SAMPLE_TID) {
6077 /* namespace issues */
6078 data->tid_entry.pid = perf_event_pid(event, current);
6079 data->tid_entry.tid = perf_event_tid(event, current);
6082 if (sample_type & PERF_SAMPLE_TIME)
6083 data->time = perf_event_clock(event);
6085 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6086 data->id = primary_event_id(event);
6088 if (sample_type & PERF_SAMPLE_STREAM_ID)
6089 data->stream_id = event->id;
6091 if (sample_type & PERF_SAMPLE_CPU) {
6092 data->cpu_entry.cpu = raw_smp_processor_id();
6093 data->cpu_entry.reserved = 0;
6097 void perf_event_header__init_id(struct perf_event_header *header,
6098 struct perf_sample_data *data,
6099 struct perf_event *event)
6101 if (event->attr.sample_id_all)
6102 __perf_event_header__init_id(header, data, event);
6105 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6106 struct perf_sample_data *data)
6108 u64 sample_type = data->type;
6110 if (sample_type & PERF_SAMPLE_TID)
6111 perf_output_put(handle, data->tid_entry);
6113 if (sample_type & PERF_SAMPLE_TIME)
6114 perf_output_put(handle, data->time);
6116 if (sample_type & PERF_SAMPLE_ID)
6117 perf_output_put(handle, data->id);
6119 if (sample_type & PERF_SAMPLE_STREAM_ID)
6120 perf_output_put(handle, data->stream_id);
6122 if (sample_type & PERF_SAMPLE_CPU)
6123 perf_output_put(handle, data->cpu_entry);
6125 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6126 perf_output_put(handle, data->id);
6129 void perf_event__output_id_sample(struct perf_event *event,
6130 struct perf_output_handle *handle,
6131 struct perf_sample_data *sample)
6133 if (event->attr.sample_id_all)
6134 __perf_event__output_id_sample(handle, sample);
6137 static void perf_output_read_one(struct perf_output_handle *handle,
6138 struct perf_event *event,
6139 u64 enabled, u64 running)
6141 u64 read_format = event->attr.read_format;
6145 values[n++] = perf_event_count(event);
6146 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6147 values[n++] = enabled +
6148 atomic64_read(&event->child_total_time_enabled);
6150 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6151 values[n++] = running +
6152 atomic64_read(&event->child_total_time_running);
6154 if (read_format & PERF_FORMAT_ID)
6155 values[n++] = primary_event_id(event);
6157 __output_copy(handle, values, n * sizeof(u64));
6160 static void perf_output_read_group(struct perf_output_handle *handle,
6161 struct perf_event *event,
6162 u64 enabled, u64 running)
6164 struct perf_event *leader = event->group_leader, *sub;
6165 u64 read_format = event->attr.read_format;
6169 values[n++] = 1 + leader->nr_siblings;
6171 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6172 values[n++] = enabled;
6174 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6175 values[n++] = running;
6177 if ((leader != event) &&
6178 (leader->state == PERF_EVENT_STATE_ACTIVE))
6179 leader->pmu->read(leader);
6181 values[n++] = perf_event_count(leader);
6182 if (read_format & PERF_FORMAT_ID)
6183 values[n++] = primary_event_id(leader);
6185 __output_copy(handle, values, n * sizeof(u64));
6187 for_each_sibling_event(sub, leader) {
6190 if ((sub != event) &&
6191 (sub->state == PERF_EVENT_STATE_ACTIVE))
6192 sub->pmu->read(sub);
6194 values[n++] = perf_event_count(sub);
6195 if (read_format & PERF_FORMAT_ID)
6196 values[n++] = primary_event_id(sub);
6198 __output_copy(handle, values, n * sizeof(u64));
6202 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6203 PERF_FORMAT_TOTAL_TIME_RUNNING)
6206 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6208 * The problem is that its both hard and excessively expensive to iterate the
6209 * child list, not to mention that its impossible to IPI the children running
6210 * on another CPU, from interrupt/NMI context.
6212 static void perf_output_read(struct perf_output_handle *handle,
6213 struct perf_event *event)
6215 u64 enabled = 0, running = 0, now;
6216 u64 read_format = event->attr.read_format;
6219 * compute total_time_enabled, total_time_running
6220 * based on snapshot values taken when the event
6221 * was last scheduled in.
6223 * we cannot simply called update_context_time()
6224 * because of locking issue as we are called in
6227 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6228 calc_timer_values(event, &now, &enabled, &running);
6230 if (event->attr.read_format & PERF_FORMAT_GROUP)
6231 perf_output_read_group(handle, event, enabled, running);
6233 perf_output_read_one(handle, event, enabled, running);
6236 void perf_output_sample(struct perf_output_handle *handle,
6237 struct perf_event_header *header,
6238 struct perf_sample_data *data,
6239 struct perf_event *event)
6241 u64 sample_type = data->type;
6243 perf_output_put(handle, *header);
6245 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6246 perf_output_put(handle, data->id);
6248 if (sample_type & PERF_SAMPLE_IP)
6249 perf_output_put(handle, data->ip);
6251 if (sample_type & PERF_SAMPLE_TID)
6252 perf_output_put(handle, data->tid_entry);
6254 if (sample_type & PERF_SAMPLE_TIME)
6255 perf_output_put(handle, data->time);
6257 if (sample_type & PERF_SAMPLE_ADDR)
6258 perf_output_put(handle, data->addr);
6260 if (sample_type & PERF_SAMPLE_ID)
6261 perf_output_put(handle, data->id);
6263 if (sample_type & PERF_SAMPLE_STREAM_ID)
6264 perf_output_put(handle, data->stream_id);
6266 if (sample_type & PERF_SAMPLE_CPU)
6267 perf_output_put(handle, data->cpu_entry);
6269 if (sample_type & PERF_SAMPLE_PERIOD)
6270 perf_output_put(handle, data->period);
6272 if (sample_type & PERF_SAMPLE_READ)
6273 perf_output_read(handle, event);
6275 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6278 size += data->callchain->nr;
6279 size *= sizeof(u64);
6280 __output_copy(handle, data->callchain, size);
6283 if (sample_type & PERF_SAMPLE_RAW) {
6284 struct perf_raw_record *raw = data->raw;
6287 struct perf_raw_frag *frag = &raw->frag;
6289 perf_output_put(handle, raw->size);
6292 __output_custom(handle, frag->copy,
6293 frag->data, frag->size);
6295 __output_copy(handle, frag->data,
6298 if (perf_raw_frag_last(frag))
6303 __output_skip(handle, NULL, frag->pad);
6309 .size = sizeof(u32),
6312 perf_output_put(handle, raw);
6316 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6317 if (data->br_stack) {
6320 size = data->br_stack->nr
6321 * sizeof(struct perf_branch_entry);
6323 perf_output_put(handle, data->br_stack->nr);
6324 perf_output_copy(handle, data->br_stack->entries, size);
6327 * we always store at least the value of nr
6330 perf_output_put(handle, nr);
6334 if (sample_type & PERF_SAMPLE_REGS_USER) {
6335 u64 abi = data->regs_user.abi;
6338 * If there are no regs to dump, notice it through
6339 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6341 perf_output_put(handle, abi);
6344 u64 mask = event->attr.sample_regs_user;
6345 perf_output_sample_regs(handle,
6346 data->regs_user.regs,
6351 if (sample_type & PERF_SAMPLE_STACK_USER) {
6352 perf_output_sample_ustack(handle,
6353 data->stack_user_size,
6354 data->regs_user.regs);
6357 if (sample_type & PERF_SAMPLE_WEIGHT)
6358 perf_output_put(handle, data->weight);
6360 if (sample_type & PERF_SAMPLE_DATA_SRC)
6361 perf_output_put(handle, data->data_src.val);
6363 if (sample_type & PERF_SAMPLE_TRANSACTION)
6364 perf_output_put(handle, data->txn);
6366 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6367 u64 abi = data->regs_intr.abi;
6369 * If there are no regs to dump, notice it through
6370 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6372 perf_output_put(handle, abi);
6375 u64 mask = event->attr.sample_regs_intr;
6377 perf_output_sample_regs(handle,
6378 data->regs_intr.regs,
6383 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6384 perf_output_put(handle, data->phys_addr);
6386 if (!event->attr.watermark) {
6387 int wakeup_events = event->attr.wakeup_events;
6389 if (wakeup_events) {
6390 struct ring_buffer *rb = handle->rb;
6391 int events = local_inc_return(&rb->events);
6393 if (events >= wakeup_events) {
6394 local_sub(wakeup_events, &rb->events);
6395 local_inc(&rb->wakeup);
6401 static u64 perf_virt_to_phys(u64 virt)
6404 struct page *p = NULL;
6409 if (virt >= TASK_SIZE) {
6410 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6411 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6412 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6413 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6416 * Walking the pages tables for user address.
6417 * Interrupts are disabled, so it prevents any tear down
6418 * of the page tables.
6419 * Try IRQ-safe __get_user_pages_fast first.
6420 * If failed, leave phys_addr as 0.
6422 if ((current->mm != NULL) &&
6423 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6424 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6433 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6435 struct perf_callchain_entry *
6436 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6438 bool kernel = !event->attr.exclude_callchain_kernel;
6439 bool user = !event->attr.exclude_callchain_user;
6440 /* Disallow cross-task user callchains. */
6441 bool crosstask = event->ctx->task && event->ctx->task != current;
6442 const u32 max_stack = event->attr.sample_max_stack;
6443 struct perf_callchain_entry *callchain;
6445 if (!kernel && !user)
6446 return &__empty_callchain;
6448 callchain = get_perf_callchain(regs, 0, kernel, user,
6449 max_stack, crosstask, true);
6450 return callchain ?: &__empty_callchain;
6453 void perf_prepare_sample(struct perf_event_header *header,
6454 struct perf_sample_data *data,
6455 struct perf_event *event,
6456 struct pt_regs *regs)
6458 u64 sample_type = event->attr.sample_type;
6460 header->type = PERF_RECORD_SAMPLE;
6461 header->size = sizeof(*header) + event->header_size;
6464 header->misc |= perf_misc_flags(regs);
6466 __perf_event_header__init_id(header, data, event);
6468 if (sample_type & PERF_SAMPLE_IP)
6469 data->ip = perf_instruction_pointer(regs);
6471 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6474 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6475 data->callchain = perf_callchain(event, regs);
6477 size += data->callchain->nr;
6479 header->size += size * sizeof(u64);
6482 if (sample_type & PERF_SAMPLE_RAW) {
6483 struct perf_raw_record *raw = data->raw;
6487 struct perf_raw_frag *frag = &raw->frag;
6492 if (perf_raw_frag_last(frag))
6497 size = round_up(sum + sizeof(u32), sizeof(u64));
6498 raw->size = size - sizeof(u32);
6499 frag->pad = raw->size - sum;
6504 header->size += size;
6507 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6508 int size = sizeof(u64); /* nr */
6509 if (data->br_stack) {
6510 size += data->br_stack->nr
6511 * sizeof(struct perf_branch_entry);
6513 header->size += size;
6516 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6517 perf_sample_regs_user(&data->regs_user, regs,
6518 &data->regs_user_copy);
6520 if (sample_type & PERF_SAMPLE_REGS_USER) {
6521 /* regs dump ABI info */
6522 int size = sizeof(u64);
6524 if (data->regs_user.regs) {
6525 u64 mask = event->attr.sample_regs_user;
6526 size += hweight64(mask) * sizeof(u64);
6529 header->size += size;
6532 if (sample_type & PERF_SAMPLE_STACK_USER) {
6534 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6535 * processed as the last one or have additional check added
6536 * in case new sample type is added, because we could eat
6537 * up the rest of the sample size.
6539 u16 stack_size = event->attr.sample_stack_user;
6540 u16 size = sizeof(u64);
6542 stack_size = perf_sample_ustack_size(stack_size, header->size,
6543 data->regs_user.regs);
6546 * If there is something to dump, add space for the dump
6547 * itself and for the field that tells the dynamic size,
6548 * which is how many have been actually dumped.
6551 size += sizeof(u64) + stack_size;
6553 data->stack_user_size = stack_size;
6554 header->size += size;
6557 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6558 /* regs dump ABI info */
6559 int size = sizeof(u64);
6561 perf_sample_regs_intr(&data->regs_intr, regs);
6563 if (data->regs_intr.regs) {
6564 u64 mask = event->attr.sample_regs_intr;
6566 size += hweight64(mask) * sizeof(u64);
6569 header->size += size;
6572 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6573 data->phys_addr = perf_virt_to_phys(data->addr);
6576 static __always_inline int
6577 __perf_event_output(struct perf_event *event,
6578 struct perf_sample_data *data,
6579 struct pt_regs *regs,
6580 int (*output_begin)(struct perf_output_handle *,
6581 struct perf_event *,
6584 struct perf_output_handle handle;
6585 struct perf_event_header header;
6588 /* protect the callchain buffers */
6591 perf_prepare_sample(&header, data, event, regs);
6593 err = output_begin(&handle, event, header.size);
6597 perf_output_sample(&handle, &header, data, event);
6599 perf_output_end(&handle);
6607 perf_event_output_forward(struct perf_event *event,
6608 struct perf_sample_data *data,
6609 struct pt_regs *regs)
6611 __perf_event_output(event, data, regs, perf_output_begin_forward);
6615 perf_event_output_backward(struct perf_event *event,
6616 struct perf_sample_data *data,
6617 struct pt_regs *regs)
6619 __perf_event_output(event, data, regs, perf_output_begin_backward);
6623 perf_event_output(struct perf_event *event,
6624 struct perf_sample_data *data,
6625 struct pt_regs *regs)
6627 return __perf_event_output(event, data, regs, perf_output_begin);
6634 struct perf_read_event {
6635 struct perf_event_header header;
6642 perf_event_read_event(struct perf_event *event,
6643 struct task_struct *task)
6645 struct perf_output_handle handle;
6646 struct perf_sample_data sample;
6647 struct perf_read_event read_event = {
6649 .type = PERF_RECORD_READ,
6651 .size = sizeof(read_event) + event->read_size,
6653 .pid = perf_event_pid(event, task),
6654 .tid = perf_event_tid(event, task),
6658 perf_event_header__init_id(&read_event.header, &sample, event);
6659 ret = perf_output_begin(&handle, event, read_event.header.size);
6663 perf_output_put(&handle, read_event);
6664 perf_output_read(&handle, event);
6665 perf_event__output_id_sample(event, &handle, &sample);
6667 perf_output_end(&handle);
6670 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6673 perf_iterate_ctx(struct perf_event_context *ctx,
6674 perf_iterate_f output,
6675 void *data, bool all)
6677 struct perf_event *event;
6679 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6681 if (event->state < PERF_EVENT_STATE_INACTIVE)
6683 if (!event_filter_match(event))
6687 output(event, data);
6691 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6693 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6694 struct perf_event *event;
6696 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6698 * Skip events that are not fully formed yet; ensure that
6699 * if we observe event->ctx, both event and ctx will be
6700 * complete enough. See perf_install_in_context().
6702 if (!smp_load_acquire(&event->ctx))
6705 if (event->state < PERF_EVENT_STATE_INACTIVE)
6707 if (!event_filter_match(event))
6709 output(event, data);
6714 * Iterate all events that need to receive side-band events.
6716 * For new callers; ensure that account_pmu_sb_event() includes
6717 * your event, otherwise it might not get delivered.
6720 perf_iterate_sb(perf_iterate_f output, void *data,
6721 struct perf_event_context *task_ctx)
6723 struct perf_event_context *ctx;
6730 * If we have task_ctx != NULL we only notify the task context itself.
6731 * The task_ctx is set only for EXIT events before releasing task
6735 perf_iterate_ctx(task_ctx, output, data, false);
6739 perf_iterate_sb_cpu(output, data);
6741 for_each_task_context_nr(ctxn) {
6742 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6744 perf_iterate_ctx(ctx, output, data, false);
6752 * Clear all file-based filters at exec, they'll have to be
6753 * re-instated when/if these objects are mmapped again.
6755 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6757 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6758 struct perf_addr_filter *filter;
6759 unsigned int restart = 0, count = 0;
6760 unsigned long flags;
6762 if (!has_addr_filter(event))
6765 raw_spin_lock_irqsave(&ifh->lock, flags);
6766 list_for_each_entry(filter, &ifh->list, entry) {
6767 if (filter->path.dentry) {
6768 event->addr_filter_ranges[count].start = 0;
6769 event->addr_filter_ranges[count].size = 0;
6777 event->addr_filters_gen++;
6778 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6781 perf_event_stop(event, 1);
6784 void perf_event_exec(void)
6786 struct perf_event_context *ctx;
6790 for_each_task_context_nr(ctxn) {
6791 ctx = current->perf_event_ctxp[ctxn];
6795 perf_event_enable_on_exec(ctxn);
6797 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6803 struct remote_output {
6804 struct ring_buffer *rb;
6808 static void __perf_event_output_stop(struct perf_event *event, void *data)
6810 struct perf_event *parent = event->parent;
6811 struct remote_output *ro = data;
6812 struct ring_buffer *rb = ro->rb;
6813 struct stop_event_data sd = {
6817 if (!has_aux(event))
6824 * In case of inheritance, it will be the parent that links to the
6825 * ring-buffer, but it will be the child that's actually using it.
6827 * We are using event::rb to determine if the event should be stopped,
6828 * however this may race with ring_buffer_attach() (through set_output),
6829 * which will make us skip the event that actually needs to be stopped.
6830 * So ring_buffer_attach() has to stop an aux event before re-assigning
6833 if (rcu_dereference(parent->rb) == rb)
6834 ro->err = __perf_event_stop(&sd);
6837 static int __perf_pmu_output_stop(void *info)
6839 struct perf_event *event = info;
6840 struct pmu *pmu = event->pmu;
6841 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6842 struct remote_output ro = {
6847 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6848 if (cpuctx->task_ctx)
6849 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6856 static void perf_pmu_output_stop(struct perf_event *event)
6858 struct perf_event *iter;
6863 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6865 * For per-CPU events, we need to make sure that neither they
6866 * nor their children are running; for cpu==-1 events it's
6867 * sufficient to stop the event itself if it's active, since
6868 * it can't have children.
6872 cpu = READ_ONCE(iter->oncpu);
6877 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6878 if (err == -EAGAIN) {
6887 * task tracking -- fork/exit
6889 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6892 struct perf_task_event {
6893 struct task_struct *task;
6894 struct perf_event_context *task_ctx;
6897 struct perf_event_header header;
6907 static int perf_event_task_match(struct perf_event *event)
6909 return event->attr.comm || event->attr.mmap ||
6910 event->attr.mmap2 || event->attr.mmap_data ||
6914 static void perf_event_task_output(struct perf_event *event,
6917 struct perf_task_event *task_event = data;
6918 struct perf_output_handle handle;
6919 struct perf_sample_data sample;
6920 struct task_struct *task = task_event->task;
6921 int ret, size = task_event->event_id.header.size;
6923 if (!perf_event_task_match(event))
6926 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6928 ret = perf_output_begin(&handle, event,
6929 task_event->event_id.header.size);
6933 task_event->event_id.pid = perf_event_pid(event, task);
6934 task_event->event_id.ppid = perf_event_pid(event, current);
6936 task_event->event_id.tid = perf_event_tid(event, task);
6937 task_event->event_id.ptid = perf_event_tid(event, current);
6939 task_event->event_id.time = perf_event_clock(event);
6941 perf_output_put(&handle, task_event->event_id);
6943 perf_event__output_id_sample(event, &handle, &sample);
6945 perf_output_end(&handle);
6947 task_event->event_id.header.size = size;
6950 static void perf_event_task(struct task_struct *task,
6951 struct perf_event_context *task_ctx,
6954 struct perf_task_event task_event;
6956 if (!atomic_read(&nr_comm_events) &&
6957 !atomic_read(&nr_mmap_events) &&
6958 !atomic_read(&nr_task_events))
6961 task_event = (struct perf_task_event){
6963 .task_ctx = task_ctx,
6966 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6968 .size = sizeof(task_event.event_id),
6978 perf_iterate_sb(perf_event_task_output,
6983 void perf_event_fork(struct task_struct *task)
6985 perf_event_task(task, NULL, 1);
6986 perf_event_namespaces(task);
6993 struct perf_comm_event {
6994 struct task_struct *task;
6999 struct perf_event_header header;
7006 static int perf_event_comm_match(struct perf_event *event)
7008 return event->attr.comm;
7011 static void perf_event_comm_output(struct perf_event *event,
7014 struct perf_comm_event *comm_event = data;
7015 struct perf_output_handle handle;
7016 struct perf_sample_data sample;
7017 int size = comm_event->event_id.header.size;
7020 if (!perf_event_comm_match(event))
7023 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7024 ret = perf_output_begin(&handle, event,
7025 comm_event->event_id.header.size);
7030 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7031 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7033 perf_output_put(&handle, comm_event->event_id);
7034 __output_copy(&handle, comm_event->comm,
7035 comm_event->comm_size);
7037 perf_event__output_id_sample(event, &handle, &sample);
7039 perf_output_end(&handle);
7041 comm_event->event_id.header.size = size;
7044 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7046 char comm[TASK_COMM_LEN];
7049 memset(comm, 0, sizeof(comm));
7050 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7051 size = ALIGN(strlen(comm)+1, sizeof(u64));
7053 comm_event->comm = comm;
7054 comm_event->comm_size = size;
7056 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7058 perf_iterate_sb(perf_event_comm_output,
7063 void perf_event_comm(struct task_struct *task, bool exec)
7065 struct perf_comm_event comm_event;
7067 if (!atomic_read(&nr_comm_events))
7070 comm_event = (struct perf_comm_event){
7076 .type = PERF_RECORD_COMM,
7077 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7085 perf_event_comm_event(&comm_event);
7089 * namespaces tracking
7092 struct perf_namespaces_event {
7093 struct task_struct *task;
7096 struct perf_event_header header;
7101 struct perf_ns_link_info link_info[NR_NAMESPACES];
7105 static int perf_event_namespaces_match(struct perf_event *event)
7107 return event->attr.namespaces;
7110 static void perf_event_namespaces_output(struct perf_event *event,
7113 struct perf_namespaces_event *namespaces_event = data;
7114 struct perf_output_handle handle;
7115 struct perf_sample_data sample;
7116 u16 header_size = namespaces_event->event_id.header.size;
7119 if (!perf_event_namespaces_match(event))
7122 perf_event_header__init_id(&namespaces_event->event_id.header,
7124 ret = perf_output_begin(&handle, event,
7125 namespaces_event->event_id.header.size);
7129 namespaces_event->event_id.pid = perf_event_pid(event,
7130 namespaces_event->task);
7131 namespaces_event->event_id.tid = perf_event_tid(event,
7132 namespaces_event->task);
7134 perf_output_put(&handle, namespaces_event->event_id);
7136 perf_event__output_id_sample(event, &handle, &sample);
7138 perf_output_end(&handle);
7140 namespaces_event->event_id.header.size = header_size;
7143 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7144 struct task_struct *task,
7145 const struct proc_ns_operations *ns_ops)
7147 struct path ns_path;
7148 struct inode *ns_inode;
7151 error = ns_get_path(&ns_path, task, ns_ops);
7153 ns_inode = ns_path.dentry->d_inode;
7154 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7155 ns_link_info->ino = ns_inode->i_ino;
7160 void perf_event_namespaces(struct task_struct *task)
7162 struct perf_namespaces_event namespaces_event;
7163 struct perf_ns_link_info *ns_link_info;
7165 if (!atomic_read(&nr_namespaces_events))
7168 namespaces_event = (struct perf_namespaces_event){
7172 .type = PERF_RECORD_NAMESPACES,
7174 .size = sizeof(namespaces_event.event_id),
7178 .nr_namespaces = NR_NAMESPACES,
7179 /* .link_info[NR_NAMESPACES] */
7183 ns_link_info = namespaces_event.event_id.link_info;
7185 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7186 task, &mntns_operations);
7188 #ifdef CONFIG_USER_NS
7189 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7190 task, &userns_operations);
7192 #ifdef CONFIG_NET_NS
7193 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7194 task, &netns_operations);
7196 #ifdef CONFIG_UTS_NS
7197 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7198 task, &utsns_operations);
7200 #ifdef CONFIG_IPC_NS
7201 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7202 task, &ipcns_operations);
7204 #ifdef CONFIG_PID_NS
7205 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7206 task, &pidns_operations);
7208 #ifdef CONFIG_CGROUPS
7209 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7210 task, &cgroupns_operations);
7213 perf_iterate_sb(perf_event_namespaces_output,
7222 struct perf_mmap_event {
7223 struct vm_area_struct *vma;
7225 const char *file_name;
7233 struct perf_event_header header;
7243 static int perf_event_mmap_match(struct perf_event *event,
7246 struct perf_mmap_event *mmap_event = data;
7247 struct vm_area_struct *vma = mmap_event->vma;
7248 int executable = vma->vm_flags & VM_EXEC;
7250 return (!executable && event->attr.mmap_data) ||
7251 (executable && (event->attr.mmap || event->attr.mmap2));
7254 static void perf_event_mmap_output(struct perf_event *event,
7257 struct perf_mmap_event *mmap_event = data;
7258 struct perf_output_handle handle;
7259 struct perf_sample_data sample;
7260 int size = mmap_event->event_id.header.size;
7261 u32 type = mmap_event->event_id.header.type;
7264 if (!perf_event_mmap_match(event, data))
7267 if (event->attr.mmap2) {
7268 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7269 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7270 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7271 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7272 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7273 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7274 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7277 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7278 ret = perf_output_begin(&handle, event,
7279 mmap_event->event_id.header.size);
7283 mmap_event->event_id.pid = perf_event_pid(event, current);
7284 mmap_event->event_id.tid = perf_event_tid(event, current);
7286 perf_output_put(&handle, mmap_event->event_id);
7288 if (event->attr.mmap2) {
7289 perf_output_put(&handle, mmap_event->maj);
7290 perf_output_put(&handle, mmap_event->min);
7291 perf_output_put(&handle, mmap_event->ino);
7292 perf_output_put(&handle, mmap_event->ino_generation);
7293 perf_output_put(&handle, mmap_event->prot);
7294 perf_output_put(&handle, mmap_event->flags);
7297 __output_copy(&handle, mmap_event->file_name,
7298 mmap_event->file_size);
7300 perf_event__output_id_sample(event, &handle, &sample);
7302 perf_output_end(&handle);
7304 mmap_event->event_id.header.size = size;
7305 mmap_event->event_id.header.type = type;
7308 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7310 struct vm_area_struct *vma = mmap_event->vma;
7311 struct file *file = vma->vm_file;
7312 int maj = 0, min = 0;
7313 u64 ino = 0, gen = 0;
7314 u32 prot = 0, flags = 0;
7320 if (vma->vm_flags & VM_READ)
7322 if (vma->vm_flags & VM_WRITE)
7324 if (vma->vm_flags & VM_EXEC)
7327 if (vma->vm_flags & VM_MAYSHARE)
7330 flags = MAP_PRIVATE;
7332 if (vma->vm_flags & VM_DENYWRITE)
7333 flags |= MAP_DENYWRITE;
7334 if (vma->vm_flags & VM_MAYEXEC)
7335 flags |= MAP_EXECUTABLE;
7336 if (vma->vm_flags & VM_LOCKED)
7337 flags |= MAP_LOCKED;
7338 if (vma->vm_flags & VM_HUGETLB)
7339 flags |= MAP_HUGETLB;
7342 struct inode *inode;
7345 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7351 * d_path() works from the end of the rb backwards, so we
7352 * need to add enough zero bytes after the string to handle
7353 * the 64bit alignment we do later.
7355 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7360 inode = file_inode(vma->vm_file);
7361 dev = inode->i_sb->s_dev;
7363 gen = inode->i_generation;
7369 if (vma->vm_ops && vma->vm_ops->name) {
7370 name = (char *) vma->vm_ops->name(vma);
7375 name = (char *)arch_vma_name(vma);
7379 if (vma->vm_start <= vma->vm_mm->start_brk &&
7380 vma->vm_end >= vma->vm_mm->brk) {
7384 if (vma->vm_start <= vma->vm_mm->start_stack &&
7385 vma->vm_end >= vma->vm_mm->start_stack) {
7395 strlcpy(tmp, name, sizeof(tmp));
7399 * Since our buffer works in 8 byte units we need to align our string
7400 * size to a multiple of 8. However, we must guarantee the tail end is
7401 * zero'd out to avoid leaking random bits to userspace.
7403 size = strlen(name)+1;
7404 while (!IS_ALIGNED(size, sizeof(u64)))
7405 name[size++] = '\0';
7407 mmap_event->file_name = name;
7408 mmap_event->file_size = size;
7409 mmap_event->maj = maj;
7410 mmap_event->min = min;
7411 mmap_event->ino = ino;
7412 mmap_event->ino_generation = gen;
7413 mmap_event->prot = prot;
7414 mmap_event->flags = flags;
7416 if (!(vma->vm_flags & VM_EXEC))
7417 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7419 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7421 perf_iterate_sb(perf_event_mmap_output,
7429 * Check whether inode and address range match filter criteria.
7431 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7432 struct file *file, unsigned long offset,
7435 /* d_inode(NULL) won't be equal to any mapped user-space file */
7436 if (!filter->path.dentry)
7439 if (d_inode(filter->path.dentry) != file_inode(file))
7442 if (filter->offset > offset + size)
7445 if (filter->offset + filter->size < offset)
7451 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7452 struct vm_area_struct *vma,
7453 struct perf_addr_filter_range *fr)
7455 unsigned long vma_size = vma->vm_end - vma->vm_start;
7456 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7457 struct file *file = vma->vm_file;
7459 if (!perf_addr_filter_match(filter, file, off, vma_size))
7462 if (filter->offset < off) {
7463 fr->start = vma->vm_start;
7464 fr->size = min(vma_size, filter->size - (off - filter->offset));
7466 fr->start = vma->vm_start + filter->offset - off;
7467 fr->size = min(vma->vm_end - fr->start, filter->size);
7473 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7475 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7476 struct vm_area_struct *vma = data;
7477 struct perf_addr_filter *filter;
7478 unsigned int restart = 0, count = 0;
7479 unsigned long flags;
7481 if (!has_addr_filter(event))
7487 raw_spin_lock_irqsave(&ifh->lock, flags);
7488 list_for_each_entry(filter, &ifh->list, entry) {
7489 if (perf_addr_filter_vma_adjust(filter, vma,
7490 &event->addr_filter_ranges[count]))
7497 event->addr_filters_gen++;
7498 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7501 perf_event_stop(event, 1);
7505 * Adjust all task's events' filters to the new vma
7507 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7509 struct perf_event_context *ctx;
7513 * Data tracing isn't supported yet and as such there is no need
7514 * to keep track of anything that isn't related to executable code:
7516 if (!(vma->vm_flags & VM_EXEC))
7520 for_each_task_context_nr(ctxn) {
7521 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7525 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7530 void perf_event_mmap(struct vm_area_struct *vma)
7532 struct perf_mmap_event mmap_event;
7534 if (!atomic_read(&nr_mmap_events))
7537 mmap_event = (struct perf_mmap_event){
7543 .type = PERF_RECORD_MMAP,
7544 .misc = PERF_RECORD_MISC_USER,
7549 .start = vma->vm_start,
7550 .len = vma->vm_end - vma->vm_start,
7551 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7553 /* .maj (attr_mmap2 only) */
7554 /* .min (attr_mmap2 only) */
7555 /* .ino (attr_mmap2 only) */
7556 /* .ino_generation (attr_mmap2 only) */
7557 /* .prot (attr_mmap2 only) */
7558 /* .flags (attr_mmap2 only) */
7561 perf_addr_filters_adjust(vma);
7562 perf_event_mmap_event(&mmap_event);
7565 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7566 unsigned long size, u64 flags)
7568 struct perf_output_handle handle;
7569 struct perf_sample_data sample;
7570 struct perf_aux_event {
7571 struct perf_event_header header;
7577 .type = PERF_RECORD_AUX,
7579 .size = sizeof(rec),
7587 perf_event_header__init_id(&rec.header, &sample, event);
7588 ret = perf_output_begin(&handle, event, rec.header.size);
7593 perf_output_put(&handle, rec);
7594 perf_event__output_id_sample(event, &handle, &sample);
7596 perf_output_end(&handle);
7600 * Lost/dropped samples logging
7602 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7604 struct perf_output_handle handle;
7605 struct perf_sample_data sample;
7609 struct perf_event_header header;
7611 } lost_samples_event = {
7613 .type = PERF_RECORD_LOST_SAMPLES,
7615 .size = sizeof(lost_samples_event),
7620 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7622 ret = perf_output_begin(&handle, event,
7623 lost_samples_event.header.size);
7627 perf_output_put(&handle, lost_samples_event);
7628 perf_event__output_id_sample(event, &handle, &sample);
7629 perf_output_end(&handle);
7633 * context_switch tracking
7636 struct perf_switch_event {
7637 struct task_struct *task;
7638 struct task_struct *next_prev;
7641 struct perf_event_header header;
7647 static int perf_event_switch_match(struct perf_event *event)
7649 return event->attr.context_switch;
7652 static void perf_event_switch_output(struct perf_event *event, void *data)
7654 struct perf_switch_event *se = data;
7655 struct perf_output_handle handle;
7656 struct perf_sample_data sample;
7659 if (!perf_event_switch_match(event))
7662 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7663 if (event->ctx->task) {
7664 se->event_id.header.type = PERF_RECORD_SWITCH;
7665 se->event_id.header.size = sizeof(se->event_id.header);
7667 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7668 se->event_id.header.size = sizeof(se->event_id);
7669 se->event_id.next_prev_pid =
7670 perf_event_pid(event, se->next_prev);
7671 se->event_id.next_prev_tid =
7672 perf_event_tid(event, se->next_prev);
7675 perf_event_header__init_id(&se->event_id.header, &sample, event);
7677 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7681 if (event->ctx->task)
7682 perf_output_put(&handle, se->event_id.header);
7684 perf_output_put(&handle, se->event_id);
7686 perf_event__output_id_sample(event, &handle, &sample);
7688 perf_output_end(&handle);
7691 static void perf_event_switch(struct task_struct *task,
7692 struct task_struct *next_prev, bool sched_in)
7694 struct perf_switch_event switch_event;
7696 /* N.B. caller checks nr_switch_events != 0 */
7698 switch_event = (struct perf_switch_event){
7700 .next_prev = next_prev,
7704 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7707 /* .next_prev_pid */
7708 /* .next_prev_tid */
7712 if (!sched_in && task->state == TASK_RUNNING)
7713 switch_event.event_id.header.misc |=
7714 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7716 perf_iterate_sb(perf_event_switch_output,
7722 * IRQ throttle logging
7725 static void perf_log_throttle(struct perf_event *event, int enable)
7727 struct perf_output_handle handle;
7728 struct perf_sample_data sample;
7732 struct perf_event_header header;
7736 } throttle_event = {
7738 .type = PERF_RECORD_THROTTLE,
7740 .size = sizeof(throttle_event),
7742 .time = perf_event_clock(event),
7743 .id = primary_event_id(event),
7744 .stream_id = event->id,
7748 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7750 perf_event_header__init_id(&throttle_event.header, &sample, event);
7752 ret = perf_output_begin(&handle, event,
7753 throttle_event.header.size);
7757 perf_output_put(&handle, throttle_event);
7758 perf_event__output_id_sample(event, &handle, &sample);
7759 perf_output_end(&handle);
7763 * ksymbol register/unregister tracking
7766 struct perf_ksymbol_event {
7770 struct perf_event_header header;
7778 static int perf_event_ksymbol_match(struct perf_event *event)
7780 return event->attr.ksymbol;
7783 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7785 struct perf_ksymbol_event *ksymbol_event = data;
7786 struct perf_output_handle handle;
7787 struct perf_sample_data sample;
7790 if (!perf_event_ksymbol_match(event))
7793 perf_event_header__init_id(&ksymbol_event->event_id.header,
7795 ret = perf_output_begin(&handle, event,
7796 ksymbol_event->event_id.header.size);
7800 perf_output_put(&handle, ksymbol_event->event_id);
7801 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7802 perf_event__output_id_sample(event, &handle, &sample);
7804 perf_output_end(&handle);
7807 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7810 struct perf_ksymbol_event ksymbol_event;
7811 char name[KSYM_NAME_LEN];
7815 if (!atomic_read(&nr_ksymbol_events))
7818 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7819 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7822 strlcpy(name, sym, KSYM_NAME_LEN);
7823 name_len = strlen(name) + 1;
7824 while (!IS_ALIGNED(name_len, sizeof(u64)))
7825 name[name_len++] = '\0';
7826 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7829 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7831 ksymbol_event = (struct perf_ksymbol_event){
7833 .name_len = name_len,
7836 .type = PERF_RECORD_KSYMBOL,
7837 .size = sizeof(ksymbol_event.event_id) +
7842 .ksym_type = ksym_type,
7847 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7850 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7854 * bpf program load/unload tracking
7857 struct perf_bpf_event {
7858 struct bpf_prog *prog;
7860 struct perf_event_header header;
7864 u8 tag[BPF_TAG_SIZE];
7868 static int perf_event_bpf_match(struct perf_event *event)
7870 return event->attr.bpf_event;
7873 static void perf_event_bpf_output(struct perf_event *event, void *data)
7875 struct perf_bpf_event *bpf_event = data;
7876 struct perf_output_handle handle;
7877 struct perf_sample_data sample;
7880 if (!perf_event_bpf_match(event))
7883 perf_event_header__init_id(&bpf_event->event_id.header,
7885 ret = perf_output_begin(&handle, event,
7886 bpf_event->event_id.header.size);
7890 perf_output_put(&handle, bpf_event->event_id);
7891 perf_event__output_id_sample(event, &handle, &sample);
7893 perf_output_end(&handle);
7896 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
7897 enum perf_bpf_event_type type)
7899 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
7900 char sym[KSYM_NAME_LEN];
7903 if (prog->aux->func_cnt == 0) {
7904 bpf_get_prog_name(prog, sym);
7905 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
7906 (u64)(unsigned long)prog->bpf_func,
7907 prog->jited_len, unregister, sym);
7909 for (i = 0; i < prog->aux->func_cnt; i++) {
7910 struct bpf_prog *subprog = prog->aux->func[i];
7912 bpf_get_prog_name(subprog, sym);
7914 PERF_RECORD_KSYMBOL_TYPE_BPF,
7915 (u64)(unsigned long)subprog->bpf_func,
7916 subprog->jited_len, unregister, sym);
7921 void perf_event_bpf_event(struct bpf_prog *prog,
7922 enum perf_bpf_event_type type,
7925 struct perf_bpf_event bpf_event;
7927 if (type <= PERF_BPF_EVENT_UNKNOWN ||
7928 type >= PERF_BPF_EVENT_MAX)
7932 case PERF_BPF_EVENT_PROG_LOAD:
7933 case PERF_BPF_EVENT_PROG_UNLOAD:
7934 if (atomic_read(&nr_ksymbol_events))
7935 perf_event_bpf_emit_ksymbols(prog, type);
7941 if (!atomic_read(&nr_bpf_events))
7944 bpf_event = (struct perf_bpf_event){
7948 .type = PERF_RECORD_BPF_EVENT,
7949 .size = sizeof(bpf_event.event_id),
7953 .id = prog->aux->id,
7957 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
7959 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
7960 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
7963 void perf_event_itrace_started(struct perf_event *event)
7965 event->attach_state |= PERF_ATTACH_ITRACE;
7968 static void perf_log_itrace_start(struct perf_event *event)
7970 struct perf_output_handle handle;
7971 struct perf_sample_data sample;
7972 struct perf_aux_event {
7973 struct perf_event_header header;
7980 event = event->parent;
7982 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7983 event->attach_state & PERF_ATTACH_ITRACE)
7986 rec.header.type = PERF_RECORD_ITRACE_START;
7987 rec.header.misc = 0;
7988 rec.header.size = sizeof(rec);
7989 rec.pid = perf_event_pid(event, current);
7990 rec.tid = perf_event_tid(event, current);
7992 perf_event_header__init_id(&rec.header, &sample, event);
7993 ret = perf_output_begin(&handle, event, rec.header.size);
7998 perf_output_put(&handle, rec);
7999 perf_event__output_id_sample(event, &handle, &sample);
8001 perf_output_end(&handle);
8005 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8007 struct hw_perf_event *hwc = &event->hw;
8011 seq = __this_cpu_read(perf_throttled_seq);
8012 if (seq != hwc->interrupts_seq) {
8013 hwc->interrupts_seq = seq;
8014 hwc->interrupts = 1;
8017 if (unlikely(throttle
8018 && hwc->interrupts >= max_samples_per_tick)) {
8019 __this_cpu_inc(perf_throttled_count);
8020 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8021 hwc->interrupts = MAX_INTERRUPTS;
8022 perf_log_throttle(event, 0);
8027 if (event->attr.freq) {
8028 u64 now = perf_clock();
8029 s64 delta = now - hwc->freq_time_stamp;
8031 hwc->freq_time_stamp = now;
8033 if (delta > 0 && delta < 2*TICK_NSEC)
8034 perf_adjust_period(event, delta, hwc->last_period, true);
8040 int perf_event_account_interrupt(struct perf_event *event)
8042 return __perf_event_account_interrupt(event, 1);
8046 * Generic event overflow handling, sampling.
8049 static int __perf_event_overflow(struct perf_event *event,
8050 int throttle, struct perf_sample_data *data,
8051 struct pt_regs *regs)
8053 int events = atomic_read(&event->event_limit);
8057 * Non-sampling counters might still use the PMI to fold short
8058 * hardware counters, ignore those.
8060 if (unlikely(!is_sampling_event(event)))
8063 ret = __perf_event_account_interrupt(event, throttle);
8066 * XXX event_limit might not quite work as expected on inherited
8070 event->pending_kill = POLL_IN;
8071 if (events && atomic_dec_and_test(&event->event_limit)) {
8073 event->pending_kill = POLL_HUP;
8075 perf_event_disable_inatomic(event);
8078 READ_ONCE(event->overflow_handler)(event, data, regs);
8080 if (*perf_event_fasync(event) && event->pending_kill) {
8081 event->pending_wakeup = 1;
8082 irq_work_queue(&event->pending);
8088 int perf_event_overflow(struct perf_event *event,
8089 struct perf_sample_data *data,
8090 struct pt_regs *regs)
8092 return __perf_event_overflow(event, 1, data, regs);
8096 * Generic software event infrastructure
8099 struct swevent_htable {
8100 struct swevent_hlist *swevent_hlist;
8101 struct mutex hlist_mutex;
8104 /* Recursion avoidance in each contexts */
8105 int recursion[PERF_NR_CONTEXTS];
8108 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8111 * We directly increment event->count and keep a second value in
8112 * event->hw.period_left to count intervals. This period event
8113 * is kept in the range [-sample_period, 0] so that we can use the
8117 u64 perf_swevent_set_period(struct perf_event *event)
8119 struct hw_perf_event *hwc = &event->hw;
8120 u64 period = hwc->last_period;
8124 hwc->last_period = hwc->sample_period;
8127 old = val = local64_read(&hwc->period_left);
8131 nr = div64_u64(period + val, period);
8132 offset = nr * period;
8134 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8140 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8141 struct perf_sample_data *data,
8142 struct pt_regs *regs)
8144 struct hw_perf_event *hwc = &event->hw;
8148 overflow = perf_swevent_set_period(event);
8150 if (hwc->interrupts == MAX_INTERRUPTS)
8153 for (; overflow; overflow--) {
8154 if (__perf_event_overflow(event, throttle,
8157 * We inhibit the overflow from happening when
8158 * hwc->interrupts == MAX_INTERRUPTS.
8166 static void perf_swevent_event(struct perf_event *event, u64 nr,
8167 struct perf_sample_data *data,
8168 struct pt_regs *regs)
8170 struct hw_perf_event *hwc = &event->hw;
8172 local64_add(nr, &event->count);
8177 if (!is_sampling_event(event))
8180 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8182 return perf_swevent_overflow(event, 1, data, regs);
8184 data->period = event->hw.last_period;
8186 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8187 return perf_swevent_overflow(event, 1, data, regs);
8189 if (local64_add_negative(nr, &hwc->period_left))
8192 perf_swevent_overflow(event, 0, data, regs);
8195 static int perf_exclude_event(struct perf_event *event,
8196 struct pt_regs *regs)
8198 if (event->hw.state & PERF_HES_STOPPED)
8202 if (event->attr.exclude_user && user_mode(regs))
8205 if (event->attr.exclude_kernel && !user_mode(regs))
8212 static int perf_swevent_match(struct perf_event *event,
8213 enum perf_type_id type,
8215 struct perf_sample_data *data,
8216 struct pt_regs *regs)
8218 if (event->attr.type != type)
8221 if (event->attr.config != event_id)
8224 if (perf_exclude_event(event, regs))
8230 static inline u64 swevent_hash(u64 type, u32 event_id)
8232 u64 val = event_id | (type << 32);
8234 return hash_64(val, SWEVENT_HLIST_BITS);
8237 static inline struct hlist_head *
8238 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8240 u64 hash = swevent_hash(type, event_id);
8242 return &hlist->heads[hash];
8245 /* For the read side: events when they trigger */
8246 static inline struct hlist_head *
8247 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8249 struct swevent_hlist *hlist;
8251 hlist = rcu_dereference(swhash->swevent_hlist);
8255 return __find_swevent_head(hlist, type, event_id);
8258 /* For the event head insertion and removal in the hlist */
8259 static inline struct hlist_head *
8260 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8262 struct swevent_hlist *hlist;
8263 u32 event_id = event->attr.config;
8264 u64 type = event->attr.type;
8267 * Event scheduling is always serialized against hlist allocation
8268 * and release. Which makes the protected version suitable here.
8269 * The context lock guarantees that.
8271 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8272 lockdep_is_held(&event->ctx->lock));
8276 return __find_swevent_head(hlist, type, event_id);
8279 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8281 struct perf_sample_data *data,
8282 struct pt_regs *regs)
8284 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8285 struct perf_event *event;
8286 struct hlist_head *head;
8289 head = find_swevent_head_rcu(swhash, type, event_id);
8293 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8294 if (perf_swevent_match(event, type, event_id, data, regs))
8295 perf_swevent_event(event, nr, data, regs);
8301 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8303 int perf_swevent_get_recursion_context(void)
8305 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8307 return get_recursion_context(swhash->recursion);
8309 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8311 void perf_swevent_put_recursion_context(int rctx)
8313 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8315 put_recursion_context(swhash->recursion, rctx);
8318 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8320 struct perf_sample_data data;
8322 if (WARN_ON_ONCE(!regs))
8325 perf_sample_data_init(&data, addr, 0);
8326 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8329 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8333 preempt_disable_notrace();
8334 rctx = perf_swevent_get_recursion_context();
8335 if (unlikely(rctx < 0))
8338 ___perf_sw_event(event_id, nr, regs, addr);
8340 perf_swevent_put_recursion_context(rctx);
8342 preempt_enable_notrace();
8345 static void perf_swevent_read(struct perf_event *event)
8349 static int perf_swevent_add(struct perf_event *event, int flags)
8351 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8352 struct hw_perf_event *hwc = &event->hw;
8353 struct hlist_head *head;
8355 if (is_sampling_event(event)) {
8356 hwc->last_period = hwc->sample_period;
8357 perf_swevent_set_period(event);
8360 hwc->state = !(flags & PERF_EF_START);
8362 head = find_swevent_head(swhash, event);
8363 if (WARN_ON_ONCE(!head))
8366 hlist_add_head_rcu(&event->hlist_entry, head);
8367 perf_event_update_userpage(event);
8372 static void perf_swevent_del(struct perf_event *event, int flags)
8374 hlist_del_rcu(&event->hlist_entry);
8377 static void perf_swevent_start(struct perf_event *event, int flags)
8379 event->hw.state = 0;
8382 static void perf_swevent_stop(struct perf_event *event, int flags)
8384 event->hw.state = PERF_HES_STOPPED;
8387 /* Deref the hlist from the update side */
8388 static inline struct swevent_hlist *
8389 swevent_hlist_deref(struct swevent_htable *swhash)
8391 return rcu_dereference_protected(swhash->swevent_hlist,
8392 lockdep_is_held(&swhash->hlist_mutex));
8395 static void swevent_hlist_release(struct swevent_htable *swhash)
8397 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8402 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8403 kfree_rcu(hlist, rcu_head);
8406 static void swevent_hlist_put_cpu(int cpu)
8408 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8410 mutex_lock(&swhash->hlist_mutex);
8412 if (!--swhash->hlist_refcount)
8413 swevent_hlist_release(swhash);
8415 mutex_unlock(&swhash->hlist_mutex);
8418 static void swevent_hlist_put(void)
8422 for_each_possible_cpu(cpu)
8423 swevent_hlist_put_cpu(cpu);
8426 static int swevent_hlist_get_cpu(int cpu)
8428 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8431 mutex_lock(&swhash->hlist_mutex);
8432 if (!swevent_hlist_deref(swhash) &&
8433 cpumask_test_cpu(cpu, perf_online_mask)) {
8434 struct swevent_hlist *hlist;
8436 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8441 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8443 swhash->hlist_refcount++;
8445 mutex_unlock(&swhash->hlist_mutex);
8450 static int swevent_hlist_get(void)
8452 int err, cpu, failed_cpu;
8454 mutex_lock(&pmus_lock);
8455 for_each_possible_cpu(cpu) {
8456 err = swevent_hlist_get_cpu(cpu);
8462 mutex_unlock(&pmus_lock);
8465 for_each_possible_cpu(cpu) {
8466 if (cpu == failed_cpu)
8468 swevent_hlist_put_cpu(cpu);
8470 mutex_unlock(&pmus_lock);
8474 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8476 static void sw_perf_event_destroy(struct perf_event *event)
8478 u64 event_id = event->attr.config;
8480 WARN_ON(event->parent);
8482 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8483 swevent_hlist_put();
8486 static int perf_swevent_init(struct perf_event *event)
8488 u64 event_id = event->attr.config;
8490 if (event->attr.type != PERF_TYPE_SOFTWARE)
8494 * no branch sampling for software events
8496 if (has_branch_stack(event))
8500 case PERF_COUNT_SW_CPU_CLOCK:
8501 case PERF_COUNT_SW_TASK_CLOCK:
8508 if (event_id >= PERF_COUNT_SW_MAX)
8511 if (!event->parent) {
8514 err = swevent_hlist_get();
8518 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8519 event->destroy = sw_perf_event_destroy;
8525 static struct pmu perf_swevent = {
8526 .task_ctx_nr = perf_sw_context,
8528 .capabilities = PERF_PMU_CAP_NO_NMI,
8530 .event_init = perf_swevent_init,
8531 .add = perf_swevent_add,
8532 .del = perf_swevent_del,
8533 .start = perf_swevent_start,
8534 .stop = perf_swevent_stop,
8535 .read = perf_swevent_read,
8538 #ifdef CONFIG_EVENT_TRACING
8540 static int perf_tp_filter_match(struct perf_event *event,
8541 struct perf_sample_data *data)
8543 void *record = data->raw->frag.data;
8545 /* only top level events have filters set */
8547 event = event->parent;
8549 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8554 static int perf_tp_event_match(struct perf_event *event,
8555 struct perf_sample_data *data,
8556 struct pt_regs *regs)
8558 if (event->hw.state & PERF_HES_STOPPED)
8561 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8563 if (event->attr.exclude_kernel && !user_mode(regs))
8566 if (!perf_tp_filter_match(event, data))
8572 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8573 struct trace_event_call *call, u64 count,
8574 struct pt_regs *regs, struct hlist_head *head,
8575 struct task_struct *task)
8577 if (bpf_prog_array_valid(call)) {
8578 *(struct pt_regs **)raw_data = regs;
8579 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8580 perf_swevent_put_recursion_context(rctx);
8584 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8587 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8589 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8590 struct pt_regs *regs, struct hlist_head *head, int rctx,
8591 struct task_struct *task)
8593 struct perf_sample_data data;
8594 struct perf_event *event;
8596 struct perf_raw_record raw = {
8603 perf_sample_data_init(&data, 0, 0);
8606 perf_trace_buf_update(record, event_type);
8608 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8609 if (perf_tp_event_match(event, &data, regs))
8610 perf_swevent_event(event, count, &data, regs);
8614 * If we got specified a target task, also iterate its context and
8615 * deliver this event there too.
8617 if (task && task != current) {
8618 struct perf_event_context *ctx;
8619 struct trace_entry *entry = record;
8622 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8626 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8627 if (event->cpu != smp_processor_id())
8629 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8631 if (event->attr.config != entry->type)
8633 if (perf_tp_event_match(event, &data, regs))
8634 perf_swevent_event(event, count, &data, regs);
8640 perf_swevent_put_recursion_context(rctx);
8642 EXPORT_SYMBOL_GPL(perf_tp_event);
8644 static void tp_perf_event_destroy(struct perf_event *event)
8646 perf_trace_destroy(event);
8649 static int perf_tp_event_init(struct perf_event *event)
8653 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8657 * no branch sampling for tracepoint events
8659 if (has_branch_stack(event))
8662 err = perf_trace_init(event);
8666 event->destroy = tp_perf_event_destroy;
8671 static struct pmu perf_tracepoint = {
8672 .task_ctx_nr = perf_sw_context,
8674 .event_init = perf_tp_event_init,
8675 .add = perf_trace_add,
8676 .del = perf_trace_del,
8677 .start = perf_swevent_start,
8678 .stop = perf_swevent_stop,
8679 .read = perf_swevent_read,
8682 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8684 * Flags in config, used by dynamic PMU kprobe and uprobe
8685 * The flags should match following PMU_FORMAT_ATTR().
8687 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8688 * if not set, create kprobe/uprobe
8690 * The following values specify a reference counter (or semaphore in the
8691 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8692 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8694 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8695 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8697 enum perf_probe_config {
8698 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8699 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8700 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8703 PMU_FORMAT_ATTR(retprobe, "config:0");
8706 #ifdef CONFIG_KPROBE_EVENTS
8707 static struct attribute *kprobe_attrs[] = {
8708 &format_attr_retprobe.attr,
8712 static struct attribute_group kprobe_format_group = {
8714 .attrs = kprobe_attrs,
8717 static const struct attribute_group *kprobe_attr_groups[] = {
8718 &kprobe_format_group,
8722 static int perf_kprobe_event_init(struct perf_event *event);
8723 static struct pmu perf_kprobe = {
8724 .task_ctx_nr = perf_sw_context,
8725 .event_init = perf_kprobe_event_init,
8726 .add = perf_trace_add,
8727 .del = perf_trace_del,
8728 .start = perf_swevent_start,
8729 .stop = perf_swevent_stop,
8730 .read = perf_swevent_read,
8731 .attr_groups = kprobe_attr_groups,
8734 static int perf_kprobe_event_init(struct perf_event *event)
8739 if (event->attr.type != perf_kprobe.type)
8742 if (!capable(CAP_SYS_ADMIN))
8746 * no branch sampling for probe events
8748 if (has_branch_stack(event))
8751 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8752 err = perf_kprobe_init(event, is_retprobe);
8756 event->destroy = perf_kprobe_destroy;
8760 #endif /* CONFIG_KPROBE_EVENTS */
8762 #ifdef CONFIG_UPROBE_EVENTS
8763 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8765 static struct attribute *uprobe_attrs[] = {
8766 &format_attr_retprobe.attr,
8767 &format_attr_ref_ctr_offset.attr,
8771 static struct attribute_group uprobe_format_group = {
8773 .attrs = uprobe_attrs,
8776 static const struct attribute_group *uprobe_attr_groups[] = {
8777 &uprobe_format_group,
8781 static int perf_uprobe_event_init(struct perf_event *event);
8782 static struct pmu perf_uprobe = {
8783 .task_ctx_nr = perf_sw_context,
8784 .event_init = perf_uprobe_event_init,
8785 .add = perf_trace_add,
8786 .del = perf_trace_del,
8787 .start = perf_swevent_start,
8788 .stop = perf_swevent_stop,
8789 .read = perf_swevent_read,
8790 .attr_groups = uprobe_attr_groups,
8793 static int perf_uprobe_event_init(struct perf_event *event)
8796 unsigned long ref_ctr_offset;
8799 if (event->attr.type != perf_uprobe.type)
8802 if (!capable(CAP_SYS_ADMIN))
8806 * no branch sampling for probe events
8808 if (has_branch_stack(event))
8811 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8812 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8813 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8817 event->destroy = perf_uprobe_destroy;
8821 #endif /* CONFIG_UPROBE_EVENTS */
8823 static inline void perf_tp_register(void)
8825 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8826 #ifdef CONFIG_KPROBE_EVENTS
8827 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8829 #ifdef CONFIG_UPROBE_EVENTS
8830 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8834 static void perf_event_free_filter(struct perf_event *event)
8836 ftrace_profile_free_filter(event);
8839 #ifdef CONFIG_BPF_SYSCALL
8840 static void bpf_overflow_handler(struct perf_event *event,
8841 struct perf_sample_data *data,
8842 struct pt_regs *regs)
8844 struct bpf_perf_event_data_kern ctx = {
8850 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8852 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8855 ret = BPF_PROG_RUN(event->prog, &ctx);
8858 __this_cpu_dec(bpf_prog_active);
8863 event->orig_overflow_handler(event, data, regs);
8866 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8868 struct bpf_prog *prog;
8870 if (event->overflow_handler_context)
8871 /* hw breakpoint or kernel counter */
8877 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8879 return PTR_ERR(prog);
8882 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8883 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8887 static void perf_event_free_bpf_handler(struct perf_event *event)
8889 struct bpf_prog *prog = event->prog;
8894 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8899 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8903 static void perf_event_free_bpf_handler(struct perf_event *event)
8909 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8910 * with perf_event_open()
8912 static inline bool perf_event_is_tracing(struct perf_event *event)
8914 if (event->pmu == &perf_tracepoint)
8916 #ifdef CONFIG_KPROBE_EVENTS
8917 if (event->pmu == &perf_kprobe)
8920 #ifdef CONFIG_UPROBE_EVENTS
8921 if (event->pmu == &perf_uprobe)
8927 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8929 bool is_kprobe, is_tracepoint, is_syscall_tp;
8930 struct bpf_prog *prog;
8933 if (!perf_event_is_tracing(event))
8934 return perf_event_set_bpf_handler(event, prog_fd);
8936 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8937 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8938 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8939 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8940 /* bpf programs can only be attached to u/kprobe or tracepoint */
8943 prog = bpf_prog_get(prog_fd);
8945 return PTR_ERR(prog);
8947 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8948 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8949 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8950 /* valid fd, but invalid bpf program type */
8955 /* Kprobe override only works for kprobes, not uprobes. */
8956 if (prog->kprobe_override &&
8957 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8962 if (is_tracepoint || is_syscall_tp) {
8963 int off = trace_event_get_offsets(event->tp_event);
8965 if (prog->aux->max_ctx_offset > off) {
8971 ret = perf_event_attach_bpf_prog(event, prog);
8977 static void perf_event_free_bpf_prog(struct perf_event *event)
8979 if (!perf_event_is_tracing(event)) {
8980 perf_event_free_bpf_handler(event);
8983 perf_event_detach_bpf_prog(event);
8988 static inline void perf_tp_register(void)
8992 static void perf_event_free_filter(struct perf_event *event)
8996 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9001 static void perf_event_free_bpf_prog(struct perf_event *event)
9004 #endif /* CONFIG_EVENT_TRACING */
9006 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9007 void perf_bp_event(struct perf_event *bp, void *data)
9009 struct perf_sample_data sample;
9010 struct pt_regs *regs = data;
9012 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9014 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9015 perf_swevent_event(bp, 1, &sample, regs);
9020 * Allocate a new address filter
9022 static struct perf_addr_filter *
9023 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9025 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9026 struct perf_addr_filter *filter;
9028 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9032 INIT_LIST_HEAD(&filter->entry);
9033 list_add_tail(&filter->entry, filters);
9038 static void free_filters_list(struct list_head *filters)
9040 struct perf_addr_filter *filter, *iter;
9042 list_for_each_entry_safe(filter, iter, filters, entry) {
9043 path_put(&filter->path);
9044 list_del(&filter->entry);
9050 * Free existing address filters and optionally install new ones
9052 static void perf_addr_filters_splice(struct perf_event *event,
9053 struct list_head *head)
9055 unsigned long flags;
9058 if (!has_addr_filter(event))
9061 /* don't bother with children, they don't have their own filters */
9065 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9067 list_splice_init(&event->addr_filters.list, &list);
9069 list_splice(head, &event->addr_filters.list);
9071 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9073 free_filters_list(&list);
9077 * Scan through mm's vmas and see if one of them matches the
9078 * @filter; if so, adjust filter's address range.
9079 * Called with mm::mmap_sem down for reading.
9081 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9082 struct mm_struct *mm,
9083 struct perf_addr_filter_range *fr)
9085 struct vm_area_struct *vma;
9087 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9091 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9097 * Update event's address range filters based on the
9098 * task's existing mappings, if any.
9100 static void perf_event_addr_filters_apply(struct perf_event *event)
9102 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9103 struct task_struct *task = READ_ONCE(event->ctx->task);
9104 struct perf_addr_filter *filter;
9105 struct mm_struct *mm = NULL;
9106 unsigned int count = 0;
9107 unsigned long flags;
9110 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9111 * will stop on the parent's child_mutex that our caller is also holding
9113 if (task == TASK_TOMBSTONE)
9116 if (ifh->nr_file_filters) {
9117 mm = get_task_mm(event->ctx->task);
9121 down_read(&mm->mmap_sem);
9124 raw_spin_lock_irqsave(&ifh->lock, flags);
9125 list_for_each_entry(filter, &ifh->list, entry) {
9126 if (filter->path.dentry) {
9128 * Adjust base offset if the filter is associated to a
9129 * binary that needs to be mapped:
9131 event->addr_filter_ranges[count].start = 0;
9132 event->addr_filter_ranges[count].size = 0;
9134 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9136 event->addr_filter_ranges[count].start = filter->offset;
9137 event->addr_filter_ranges[count].size = filter->size;
9143 event->addr_filters_gen++;
9144 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9146 if (ifh->nr_file_filters) {
9147 up_read(&mm->mmap_sem);
9153 perf_event_stop(event, 1);
9157 * Address range filtering: limiting the data to certain
9158 * instruction address ranges. Filters are ioctl()ed to us from
9159 * userspace as ascii strings.
9161 * Filter string format:
9164 * where ACTION is one of the
9165 * * "filter": limit the trace to this region
9166 * * "start": start tracing from this address
9167 * * "stop": stop tracing at this address/region;
9169 * * for kernel addresses: <start address>[/<size>]
9170 * * for object files: <start address>[/<size>]@</path/to/object/file>
9172 * if <size> is not specified or is zero, the range is treated as a single
9173 * address; not valid for ACTION=="filter".
9187 IF_STATE_ACTION = 0,
9192 static const match_table_t if_tokens = {
9193 { IF_ACT_FILTER, "filter" },
9194 { IF_ACT_START, "start" },
9195 { IF_ACT_STOP, "stop" },
9196 { IF_SRC_FILE, "%u/%u@%s" },
9197 { IF_SRC_KERNEL, "%u/%u" },
9198 { IF_SRC_FILEADDR, "%u@%s" },
9199 { IF_SRC_KERNELADDR, "%u" },
9200 { IF_ACT_NONE, NULL },
9204 * Address filter string parser
9207 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9208 struct list_head *filters)
9210 struct perf_addr_filter *filter = NULL;
9211 char *start, *orig, *filename = NULL;
9212 substring_t args[MAX_OPT_ARGS];
9213 int state = IF_STATE_ACTION, token;
9214 unsigned int kernel = 0;
9217 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9221 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9222 static const enum perf_addr_filter_action_t actions[] = {
9223 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9224 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9225 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9232 /* filter definition begins */
9233 if (state == IF_STATE_ACTION) {
9234 filter = perf_addr_filter_new(event, filters);
9239 token = match_token(start, if_tokens, args);
9244 if (state != IF_STATE_ACTION)
9247 filter->action = actions[token];
9248 state = IF_STATE_SOURCE;
9251 case IF_SRC_KERNELADDR:
9256 case IF_SRC_FILEADDR:
9258 if (state != IF_STATE_SOURCE)
9262 ret = kstrtoul(args[0].from, 0, &filter->offset);
9266 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9268 ret = kstrtoul(args[1].from, 0, &filter->size);
9273 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9274 int fpos = token == IF_SRC_FILE ? 2 : 1;
9276 filename = match_strdup(&args[fpos]);
9283 state = IF_STATE_END;
9291 * Filter definition is fully parsed, validate and install it.
9292 * Make sure that it doesn't contradict itself or the event's
9295 if (state == IF_STATE_END) {
9297 if (kernel && event->attr.exclude_kernel)
9301 * ACTION "filter" must have a non-zero length region
9304 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9313 * For now, we only support file-based filters
9314 * in per-task events; doing so for CPU-wide
9315 * events requires additional context switching
9316 * trickery, since same object code will be
9317 * mapped at different virtual addresses in
9318 * different processes.
9321 if (!event->ctx->task)
9322 goto fail_free_name;
9324 /* look up the path and grab its inode */
9325 ret = kern_path(filename, LOOKUP_FOLLOW,
9328 goto fail_free_name;
9334 if (!filter->path.dentry ||
9335 !S_ISREG(d_inode(filter->path.dentry)
9339 event->addr_filters.nr_file_filters++;
9342 /* ready to consume more filters */
9343 state = IF_STATE_ACTION;
9348 if (state != IF_STATE_ACTION)
9358 free_filters_list(filters);
9365 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9371 * Since this is called in perf_ioctl() path, we're already holding
9374 lockdep_assert_held(&event->ctx->mutex);
9376 if (WARN_ON_ONCE(event->parent))
9379 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9381 goto fail_clear_files;
9383 ret = event->pmu->addr_filters_validate(&filters);
9385 goto fail_free_filters;
9387 /* remove existing filters, if any */
9388 perf_addr_filters_splice(event, &filters);
9390 /* install new filters */
9391 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9396 free_filters_list(&filters);
9399 event->addr_filters.nr_file_filters = 0;
9404 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9409 filter_str = strndup_user(arg, PAGE_SIZE);
9410 if (IS_ERR(filter_str))
9411 return PTR_ERR(filter_str);
9413 #ifdef CONFIG_EVENT_TRACING
9414 if (perf_event_is_tracing(event)) {
9415 struct perf_event_context *ctx = event->ctx;
9418 * Beware, here be dragons!!
9420 * the tracepoint muck will deadlock against ctx->mutex, but
9421 * the tracepoint stuff does not actually need it. So
9422 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9423 * already have a reference on ctx.
9425 * This can result in event getting moved to a different ctx,
9426 * but that does not affect the tracepoint state.
9428 mutex_unlock(&ctx->mutex);
9429 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9430 mutex_lock(&ctx->mutex);
9433 if (has_addr_filter(event))
9434 ret = perf_event_set_addr_filter(event, filter_str);
9441 * hrtimer based swevent callback
9444 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9446 enum hrtimer_restart ret = HRTIMER_RESTART;
9447 struct perf_sample_data data;
9448 struct pt_regs *regs;
9449 struct perf_event *event;
9452 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9454 if (event->state != PERF_EVENT_STATE_ACTIVE)
9455 return HRTIMER_NORESTART;
9457 event->pmu->read(event);
9459 perf_sample_data_init(&data, 0, event->hw.last_period);
9460 regs = get_irq_regs();
9462 if (regs && !perf_exclude_event(event, regs)) {
9463 if (!(event->attr.exclude_idle && is_idle_task(current)))
9464 if (__perf_event_overflow(event, 1, &data, regs))
9465 ret = HRTIMER_NORESTART;
9468 period = max_t(u64, 10000, event->hw.sample_period);
9469 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9474 static void perf_swevent_start_hrtimer(struct perf_event *event)
9476 struct hw_perf_event *hwc = &event->hw;
9479 if (!is_sampling_event(event))
9482 period = local64_read(&hwc->period_left);
9487 local64_set(&hwc->period_left, 0);
9489 period = max_t(u64, 10000, hwc->sample_period);
9491 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9492 HRTIMER_MODE_REL_PINNED);
9495 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9497 struct hw_perf_event *hwc = &event->hw;
9499 if (is_sampling_event(event)) {
9500 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9501 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9503 hrtimer_cancel(&hwc->hrtimer);
9507 static void perf_swevent_init_hrtimer(struct perf_event *event)
9509 struct hw_perf_event *hwc = &event->hw;
9511 if (!is_sampling_event(event))
9514 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9515 hwc->hrtimer.function = perf_swevent_hrtimer;
9518 * Since hrtimers have a fixed rate, we can do a static freq->period
9519 * mapping and avoid the whole period adjust feedback stuff.
9521 if (event->attr.freq) {
9522 long freq = event->attr.sample_freq;
9524 event->attr.sample_period = NSEC_PER_SEC / freq;
9525 hwc->sample_period = event->attr.sample_period;
9526 local64_set(&hwc->period_left, hwc->sample_period);
9527 hwc->last_period = hwc->sample_period;
9528 event->attr.freq = 0;
9533 * Software event: cpu wall time clock
9536 static void cpu_clock_event_update(struct perf_event *event)
9541 now = local_clock();
9542 prev = local64_xchg(&event->hw.prev_count, now);
9543 local64_add(now - prev, &event->count);
9546 static void cpu_clock_event_start(struct perf_event *event, int flags)
9548 local64_set(&event->hw.prev_count, local_clock());
9549 perf_swevent_start_hrtimer(event);
9552 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9554 perf_swevent_cancel_hrtimer(event);
9555 cpu_clock_event_update(event);
9558 static int cpu_clock_event_add(struct perf_event *event, int flags)
9560 if (flags & PERF_EF_START)
9561 cpu_clock_event_start(event, flags);
9562 perf_event_update_userpage(event);
9567 static void cpu_clock_event_del(struct perf_event *event, int flags)
9569 cpu_clock_event_stop(event, flags);
9572 static void cpu_clock_event_read(struct perf_event *event)
9574 cpu_clock_event_update(event);
9577 static int cpu_clock_event_init(struct perf_event *event)
9579 if (event->attr.type != PERF_TYPE_SOFTWARE)
9582 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9586 * no branch sampling for software events
9588 if (has_branch_stack(event))
9591 perf_swevent_init_hrtimer(event);
9596 static struct pmu perf_cpu_clock = {
9597 .task_ctx_nr = perf_sw_context,
9599 .capabilities = PERF_PMU_CAP_NO_NMI,
9601 .event_init = cpu_clock_event_init,
9602 .add = cpu_clock_event_add,
9603 .del = cpu_clock_event_del,
9604 .start = cpu_clock_event_start,
9605 .stop = cpu_clock_event_stop,
9606 .read = cpu_clock_event_read,
9610 * Software event: task time clock
9613 static void task_clock_event_update(struct perf_event *event, u64 now)
9618 prev = local64_xchg(&event->hw.prev_count, now);
9620 local64_add(delta, &event->count);
9623 static void task_clock_event_start(struct perf_event *event, int flags)
9625 local64_set(&event->hw.prev_count, event->ctx->time);
9626 perf_swevent_start_hrtimer(event);
9629 static void task_clock_event_stop(struct perf_event *event, int flags)
9631 perf_swevent_cancel_hrtimer(event);
9632 task_clock_event_update(event, event->ctx->time);
9635 static int task_clock_event_add(struct perf_event *event, int flags)
9637 if (flags & PERF_EF_START)
9638 task_clock_event_start(event, flags);
9639 perf_event_update_userpage(event);
9644 static void task_clock_event_del(struct perf_event *event, int flags)
9646 task_clock_event_stop(event, PERF_EF_UPDATE);
9649 static void task_clock_event_read(struct perf_event *event)
9651 u64 now = perf_clock();
9652 u64 delta = now - event->ctx->timestamp;
9653 u64 time = event->ctx->time + delta;
9655 task_clock_event_update(event, time);
9658 static int task_clock_event_init(struct perf_event *event)
9660 if (event->attr.type != PERF_TYPE_SOFTWARE)
9663 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9667 * no branch sampling for software events
9669 if (has_branch_stack(event))
9672 perf_swevent_init_hrtimer(event);
9677 static struct pmu perf_task_clock = {
9678 .task_ctx_nr = perf_sw_context,
9680 .capabilities = PERF_PMU_CAP_NO_NMI,
9682 .event_init = task_clock_event_init,
9683 .add = task_clock_event_add,
9684 .del = task_clock_event_del,
9685 .start = task_clock_event_start,
9686 .stop = task_clock_event_stop,
9687 .read = task_clock_event_read,
9690 static void perf_pmu_nop_void(struct pmu *pmu)
9694 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9698 static int perf_pmu_nop_int(struct pmu *pmu)
9703 static int perf_event_nop_int(struct perf_event *event, u64 value)
9708 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9710 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9712 __this_cpu_write(nop_txn_flags, flags);
9714 if (flags & ~PERF_PMU_TXN_ADD)
9717 perf_pmu_disable(pmu);
9720 static int perf_pmu_commit_txn(struct pmu *pmu)
9722 unsigned int flags = __this_cpu_read(nop_txn_flags);
9724 __this_cpu_write(nop_txn_flags, 0);
9726 if (flags & ~PERF_PMU_TXN_ADD)
9729 perf_pmu_enable(pmu);
9733 static void perf_pmu_cancel_txn(struct pmu *pmu)
9735 unsigned int flags = __this_cpu_read(nop_txn_flags);
9737 __this_cpu_write(nop_txn_flags, 0);
9739 if (flags & ~PERF_PMU_TXN_ADD)
9742 perf_pmu_enable(pmu);
9745 static int perf_event_idx_default(struct perf_event *event)
9751 * Ensures all contexts with the same task_ctx_nr have the same
9752 * pmu_cpu_context too.
9754 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9761 list_for_each_entry(pmu, &pmus, entry) {
9762 if (pmu->task_ctx_nr == ctxn)
9763 return pmu->pmu_cpu_context;
9769 static void free_pmu_context(struct pmu *pmu)
9772 * Static contexts such as perf_sw_context have a global lifetime
9773 * and may be shared between different PMUs. Avoid freeing them
9774 * when a single PMU is going away.
9776 if (pmu->task_ctx_nr > perf_invalid_context)
9779 free_percpu(pmu->pmu_cpu_context);
9783 * Let userspace know that this PMU supports address range filtering:
9785 static ssize_t nr_addr_filters_show(struct device *dev,
9786 struct device_attribute *attr,
9789 struct pmu *pmu = dev_get_drvdata(dev);
9791 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9793 DEVICE_ATTR_RO(nr_addr_filters);
9795 static struct idr pmu_idr;
9798 type_show(struct device *dev, struct device_attribute *attr, char *page)
9800 struct pmu *pmu = dev_get_drvdata(dev);
9802 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9804 static DEVICE_ATTR_RO(type);
9807 perf_event_mux_interval_ms_show(struct device *dev,
9808 struct device_attribute *attr,
9811 struct pmu *pmu = dev_get_drvdata(dev);
9813 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9816 static DEFINE_MUTEX(mux_interval_mutex);
9819 perf_event_mux_interval_ms_store(struct device *dev,
9820 struct device_attribute *attr,
9821 const char *buf, size_t count)
9823 struct pmu *pmu = dev_get_drvdata(dev);
9824 int timer, cpu, ret;
9826 ret = kstrtoint(buf, 0, &timer);
9833 /* same value, noting to do */
9834 if (timer == pmu->hrtimer_interval_ms)
9837 mutex_lock(&mux_interval_mutex);
9838 pmu->hrtimer_interval_ms = timer;
9840 /* update all cpuctx for this PMU */
9842 for_each_online_cpu(cpu) {
9843 struct perf_cpu_context *cpuctx;
9844 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9845 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9847 cpu_function_call(cpu,
9848 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9851 mutex_unlock(&mux_interval_mutex);
9855 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9857 static struct attribute *pmu_dev_attrs[] = {
9858 &dev_attr_type.attr,
9859 &dev_attr_perf_event_mux_interval_ms.attr,
9862 ATTRIBUTE_GROUPS(pmu_dev);
9864 static int pmu_bus_running;
9865 static struct bus_type pmu_bus = {
9866 .name = "event_source",
9867 .dev_groups = pmu_dev_groups,
9870 static void pmu_dev_release(struct device *dev)
9875 static int pmu_dev_alloc(struct pmu *pmu)
9879 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9883 pmu->dev->groups = pmu->attr_groups;
9884 device_initialize(pmu->dev);
9885 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9889 dev_set_drvdata(pmu->dev, pmu);
9890 pmu->dev->bus = &pmu_bus;
9891 pmu->dev->release = pmu_dev_release;
9892 ret = device_add(pmu->dev);
9896 /* For PMUs with address filters, throw in an extra attribute: */
9897 if (pmu->nr_addr_filters)
9898 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9903 if (pmu->attr_update)
9904 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
9913 device_del(pmu->dev);
9916 put_device(pmu->dev);
9920 static struct lock_class_key cpuctx_mutex;
9921 static struct lock_class_key cpuctx_lock;
9923 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9927 mutex_lock(&pmus_lock);
9929 pmu->pmu_disable_count = alloc_percpu(int);
9930 if (!pmu->pmu_disable_count)
9939 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9947 if (pmu_bus_running) {
9948 ret = pmu_dev_alloc(pmu);
9954 if (pmu->task_ctx_nr == perf_hw_context) {
9955 static int hw_context_taken = 0;
9958 * Other than systems with heterogeneous CPUs, it never makes
9959 * sense for two PMUs to share perf_hw_context. PMUs which are
9960 * uncore must use perf_invalid_context.
9962 if (WARN_ON_ONCE(hw_context_taken &&
9963 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9964 pmu->task_ctx_nr = perf_invalid_context;
9966 hw_context_taken = 1;
9969 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9970 if (pmu->pmu_cpu_context)
9971 goto got_cpu_context;
9974 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9975 if (!pmu->pmu_cpu_context)
9978 for_each_possible_cpu(cpu) {
9979 struct perf_cpu_context *cpuctx;
9981 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9982 __perf_event_init_context(&cpuctx->ctx);
9983 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9984 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9985 cpuctx->ctx.pmu = pmu;
9986 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9988 __perf_mux_hrtimer_init(cpuctx, cpu);
9992 if (!pmu->start_txn) {
9993 if (pmu->pmu_enable) {
9995 * If we have pmu_enable/pmu_disable calls, install
9996 * transaction stubs that use that to try and batch
9997 * hardware accesses.
9999 pmu->start_txn = perf_pmu_start_txn;
10000 pmu->commit_txn = perf_pmu_commit_txn;
10001 pmu->cancel_txn = perf_pmu_cancel_txn;
10003 pmu->start_txn = perf_pmu_nop_txn;
10004 pmu->commit_txn = perf_pmu_nop_int;
10005 pmu->cancel_txn = perf_pmu_nop_void;
10009 if (!pmu->pmu_enable) {
10010 pmu->pmu_enable = perf_pmu_nop_void;
10011 pmu->pmu_disable = perf_pmu_nop_void;
10014 if (!pmu->check_period)
10015 pmu->check_period = perf_event_nop_int;
10017 if (!pmu->event_idx)
10018 pmu->event_idx = perf_event_idx_default;
10020 list_add_rcu(&pmu->entry, &pmus);
10021 atomic_set(&pmu->exclusive_cnt, 0);
10024 mutex_unlock(&pmus_lock);
10029 device_del(pmu->dev);
10030 put_device(pmu->dev);
10033 if (pmu->type >= PERF_TYPE_MAX)
10034 idr_remove(&pmu_idr, pmu->type);
10037 free_percpu(pmu->pmu_disable_count);
10040 EXPORT_SYMBOL_GPL(perf_pmu_register);
10042 void perf_pmu_unregister(struct pmu *pmu)
10044 mutex_lock(&pmus_lock);
10045 list_del_rcu(&pmu->entry);
10048 * We dereference the pmu list under both SRCU and regular RCU, so
10049 * synchronize against both of those.
10051 synchronize_srcu(&pmus_srcu);
10054 free_percpu(pmu->pmu_disable_count);
10055 if (pmu->type >= PERF_TYPE_MAX)
10056 idr_remove(&pmu_idr, pmu->type);
10057 if (pmu_bus_running) {
10058 if (pmu->nr_addr_filters)
10059 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10060 device_del(pmu->dev);
10061 put_device(pmu->dev);
10063 free_pmu_context(pmu);
10064 mutex_unlock(&pmus_lock);
10066 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10068 static inline bool has_extended_regs(struct perf_event *event)
10070 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10071 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10074 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10076 struct perf_event_context *ctx = NULL;
10079 if (!try_module_get(pmu->module))
10083 * A number of pmu->event_init() methods iterate the sibling_list to,
10084 * for example, validate if the group fits on the PMU. Therefore,
10085 * if this is a sibling event, acquire the ctx->mutex to protect
10086 * the sibling_list.
10088 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10090 * This ctx->mutex can nest when we're called through
10091 * inheritance. See the perf_event_ctx_lock_nested() comment.
10093 ctx = perf_event_ctx_lock_nested(event->group_leader,
10094 SINGLE_DEPTH_NESTING);
10099 ret = pmu->event_init(event);
10102 perf_event_ctx_unlock(event->group_leader, ctx);
10105 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10106 has_extended_regs(event))
10109 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10110 event_has_any_exclude_flag(event))
10113 if (ret && event->destroy)
10114 event->destroy(event);
10118 module_put(pmu->module);
10123 static struct pmu *perf_init_event(struct perf_event *event)
10129 idx = srcu_read_lock(&pmus_srcu);
10131 /* Try parent's PMU first: */
10132 if (event->parent && event->parent->pmu) {
10133 pmu = event->parent->pmu;
10134 ret = perf_try_init_event(pmu, event);
10140 pmu = idr_find(&pmu_idr, event->attr.type);
10143 ret = perf_try_init_event(pmu, event);
10145 pmu = ERR_PTR(ret);
10149 list_for_each_entry_rcu(pmu, &pmus, entry) {
10150 ret = perf_try_init_event(pmu, event);
10154 if (ret != -ENOENT) {
10155 pmu = ERR_PTR(ret);
10159 pmu = ERR_PTR(-ENOENT);
10161 srcu_read_unlock(&pmus_srcu, idx);
10166 static void attach_sb_event(struct perf_event *event)
10168 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10170 raw_spin_lock(&pel->lock);
10171 list_add_rcu(&event->sb_list, &pel->list);
10172 raw_spin_unlock(&pel->lock);
10176 * We keep a list of all !task (and therefore per-cpu) events
10177 * that need to receive side-band records.
10179 * This avoids having to scan all the various PMU per-cpu contexts
10180 * looking for them.
10182 static void account_pmu_sb_event(struct perf_event *event)
10184 if (is_sb_event(event))
10185 attach_sb_event(event);
10188 static void account_event_cpu(struct perf_event *event, int cpu)
10193 if (is_cgroup_event(event))
10194 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10197 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10198 static void account_freq_event_nohz(void)
10200 #ifdef CONFIG_NO_HZ_FULL
10201 /* Lock so we don't race with concurrent unaccount */
10202 spin_lock(&nr_freq_lock);
10203 if (atomic_inc_return(&nr_freq_events) == 1)
10204 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10205 spin_unlock(&nr_freq_lock);
10209 static void account_freq_event(void)
10211 if (tick_nohz_full_enabled())
10212 account_freq_event_nohz();
10214 atomic_inc(&nr_freq_events);
10218 static void account_event(struct perf_event *event)
10225 if (event->attach_state & PERF_ATTACH_TASK)
10227 if (event->attr.mmap || event->attr.mmap_data)
10228 atomic_inc(&nr_mmap_events);
10229 if (event->attr.comm)
10230 atomic_inc(&nr_comm_events);
10231 if (event->attr.namespaces)
10232 atomic_inc(&nr_namespaces_events);
10233 if (event->attr.task)
10234 atomic_inc(&nr_task_events);
10235 if (event->attr.freq)
10236 account_freq_event();
10237 if (event->attr.context_switch) {
10238 atomic_inc(&nr_switch_events);
10241 if (has_branch_stack(event))
10243 if (is_cgroup_event(event))
10245 if (event->attr.ksymbol)
10246 atomic_inc(&nr_ksymbol_events);
10247 if (event->attr.bpf_event)
10248 atomic_inc(&nr_bpf_events);
10252 * We need the mutex here because static_branch_enable()
10253 * must complete *before* the perf_sched_count increment
10256 if (atomic_inc_not_zero(&perf_sched_count))
10259 mutex_lock(&perf_sched_mutex);
10260 if (!atomic_read(&perf_sched_count)) {
10261 static_branch_enable(&perf_sched_events);
10263 * Guarantee that all CPUs observe they key change and
10264 * call the perf scheduling hooks before proceeding to
10265 * install events that need them.
10270 * Now that we have waited for the sync_sched(), allow further
10271 * increments to by-pass the mutex.
10273 atomic_inc(&perf_sched_count);
10274 mutex_unlock(&perf_sched_mutex);
10278 account_event_cpu(event, event->cpu);
10280 account_pmu_sb_event(event);
10284 * Allocate and initialize an event structure
10286 static struct perf_event *
10287 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10288 struct task_struct *task,
10289 struct perf_event *group_leader,
10290 struct perf_event *parent_event,
10291 perf_overflow_handler_t overflow_handler,
10292 void *context, int cgroup_fd)
10295 struct perf_event *event;
10296 struct hw_perf_event *hwc;
10297 long err = -EINVAL;
10299 if ((unsigned)cpu >= nr_cpu_ids) {
10300 if (!task || cpu != -1)
10301 return ERR_PTR(-EINVAL);
10304 event = kzalloc(sizeof(*event), GFP_KERNEL);
10306 return ERR_PTR(-ENOMEM);
10309 * Single events are their own group leaders, with an
10310 * empty sibling list:
10313 group_leader = event;
10315 mutex_init(&event->child_mutex);
10316 INIT_LIST_HEAD(&event->child_list);
10318 INIT_LIST_HEAD(&event->event_entry);
10319 INIT_LIST_HEAD(&event->sibling_list);
10320 INIT_LIST_HEAD(&event->active_list);
10321 init_event_group(event);
10322 INIT_LIST_HEAD(&event->rb_entry);
10323 INIT_LIST_HEAD(&event->active_entry);
10324 INIT_LIST_HEAD(&event->addr_filters.list);
10325 INIT_HLIST_NODE(&event->hlist_entry);
10328 init_waitqueue_head(&event->waitq);
10329 event->pending_disable = -1;
10330 init_irq_work(&event->pending, perf_pending_event);
10332 mutex_init(&event->mmap_mutex);
10333 raw_spin_lock_init(&event->addr_filters.lock);
10335 atomic_long_set(&event->refcount, 1);
10337 event->attr = *attr;
10338 event->group_leader = group_leader;
10342 event->parent = parent_event;
10344 event->ns = get_pid_ns(task_active_pid_ns(current));
10345 event->id = atomic64_inc_return(&perf_event_id);
10347 event->state = PERF_EVENT_STATE_INACTIVE;
10350 event->attach_state = PERF_ATTACH_TASK;
10352 * XXX pmu::event_init needs to know what task to account to
10353 * and we cannot use the ctx information because we need the
10354 * pmu before we get a ctx.
10356 event->hw.target = get_task_struct(task);
10359 event->clock = &local_clock;
10361 event->clock = parent_event->clock;
10363 if (!overflow_handler && parent_event) {
10364 overflow_handler = parent_event->overflow_handler;
10365 context = parent_event->overflow_handler_context;
10366 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10367 if (overflow_handler == bpf_overflow_handler) {
10368 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10370 if (IS_ERR(prog)) {
10371 err = PTR_ERR(prog);
10374 event->prog = prog;
10375 event->orig_overflow_handler =
10376 parent_event->orig_overflow_handler;
10381 if (overflow_handler) {
10382 event->overflow_handler = overflow_handler;
10383 event->overflow_handler_context = context;
10384 } else if (is_write_backward(event)){
10385 event->overflow_handler = perf_event_output_backward;
10386 event->overflow_handler_context = NULL;
10388 event->overflow_handler = perf_event_output_forward;
10389 event->overflow_handler_context = NULL;
10392 perf_event__state_init(event);
10397 hwc->sample_period = attr->sample_period;
10398 if (attr->freq && attr->sample_freq)
10399 hwc->sample_period = 1;
10400 hwc->last_period = hwc->sample_period;
10402 local64_set(&hwc->period_left, hwc->sample_period);
10405 * We currently do not support PERF_SAMPLE_READ on inherited events.
10406 * See perf_output_read().
10408 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10411 if (!has_branch_stack(event))
10412 event->attr.branch_sample_type = 0;
10414 if (cgroup_fd != -1) {
10415 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10420 pmu = perf_init_event(event);
10422 err = PTR_ERR(pmu);
10426 err = exclusive_event_init(event);
10430 if (has_addr_filter(event)) {
10431 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10432 sizeof(struct perf_addr_filter_range),
10434 if (!event->addr_filter_ranges) {
10440 * Clone the parent's vma offsets: they are valid until exec()
10441 * even if the mm is not shared with the parent.
10443 if (event->parent) {
10444 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10446 raw_spin_lock_irq(&ifh->lock);
10447 memcpy(event->addr_filter_ranges,
10448 event->parent->addr_filter_ranges,
10449 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10450 raw_spin_unlock_irq(&ifh->lock);
10453 /* force hw sync on the address filters */
10454 event->addr_filters_gen = 1;
10457 if (!event->parent) {
10458 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10459 err = get_callchain_buffers(attr->sample_max_stack);
10461 goto err_addr_filters;
10465 /* symmetric to unaccount_event() in _free_event() */
10466 account_event(event);
10471 kfree(event->addr_filter_ranges);
10474 exclusive_event_destroy(event);
10477 if (event->destroy)
10478 event->destroy(event);
10479 module_put(pmu->module);
10481 if (is_cgroup_event(event))
10482 perf_detach_cgroup(event);
10484 put_pid_ns(event->ns);
10485 if (event->hw.target)
10486 put_task_struct(event->hw.target);
10489 return ERR_PTR(err);
10492 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10493 struct perf_event_attr *attr)
10498 if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
10502 * zero the full structure, so that a short copy will be nice.
10504 memset(attr, 0, sizeof(*attr));
10506 ret = get_user(size, &uattr->size);
10510 if (size > PAGE_SIZE) /* silly large */
10513 if (!size) /* abi compat */
10514 size = PERF_ATTR_SIZE_VER0;
10516 if (size < PERF_ATTR_SIZE_VER0)
10520 * If we're handed a bigger struct than we know of,
10521 * ensure all the unknown bits are 0 - i.e. new
10522 * user-space does not rely on any kernel feature
10523 * extensions we dont know about yet.
10525 if (size > sizeof(*attr)) {
10526 unsigned char __user *addr;
10527 unsigned char __user *end;
10530 addr = (void __user *)uattr + sizeof(*attr);
10531 end = (void __user *)uattr + size;
10533 for (; addr < end; addr++) {
10534 ret = get_user(val, addr);
10540 size = sizeof(*attr);
10543 ret = copy_from_user(attr, uattr, size);
10549 if (attr->__reserved_1)
10552 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10555 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10558 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10559 u64 mask = attr->branch_sample_type;
10561 /* only using defined bits */
10562 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10565 /* at least one branch bit must be set */
10566 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10569 /* propagate priv level, when not set for branch */
10570 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10572 /* exclude_kernel checked on syscall entry */
10573 if (!attr->exclude_kernel)
10574 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10576 if (!attr->exclude_user)
10577 mask |= PERF_SAMPLE_BRANCH_USER;
10579 if (!attr->exclude_hv)
10580 mask |= PERF_SAMPLE_BRANCH_HV;
10582 * adjust user setting (for HW filter setup)
10584 attr->branch_sample_type = mask;
10586 /* privileged levels capture (kernel, hv): check permissions */
10587 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10588 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10592 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10593 ret = perf_reg_validate(attr->sample_regs_user);
10598 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10599 if (!arch_perf_have_user_stack_dump())
10603 * We have __u32 type for the size, but so far
10604 * we can only use __u16 as maximum due to the
10605 * __u16 sample size limit.
10607 if (attr->sample_stack_user >= USHRT_MAX)
10609 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10613 if (!attr->sample_max_stack)
10614 attr->sample_max_stack = sysctl_perf_event_max_stack;
10616 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10617 ret = perf_reg_validate(attr->sample_regs_intr);
10622 put_user(sizeof(*attr), &uattr->size);
10628 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10630 struct ring_buffer *rb = NULL;
10636 /* don't allow circular references */
10637 if (event == output_event)
10641 * Don't allow cross-cpu buffers
10643 if (output_event->cpu != event->cpu)
10647 * If its not a per-cpu rb, it must be the same task.
10649 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10653 * Mixing clocks in the same buffer is trouble you don't need.
10655 if (output_event->clock != event->clock)
10659 * Either writing ring buffer from beginning or from end.
10660 * Mixing is not allowed.
10662 if (is_write_backward(output_event) != is_write_backward(event))
10666 * If both events generate aux data, they must be on the same PMU
10668 if (has_aux(event) && has_aux(output_event) &&
10669 event->pmu != output_event->pmu)
10673 mutex_lock(&event->mmap_mutex);
10674 /* Can't redirect output if we've got an active mmap() */
10675 if (atomic_read(&event->mmap_count))
10678 if (output_event) {
10679 /* get the rb we want to redirect to */
10680 rb = ring_buffer_get(output_event);
10685 ring_buffer_attach(event, rb);
10689 mutex_unlock(&event->mmap_mutex);
10695 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10701 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10704 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10706 bool nmi_safe = false;
10709 case CLOCK_MONOTONIC:
10710 event->clock = &ktime_get_mono_fast_ns;
10714 case CLOCK_MONOTONIC_RAW:
10715 event->clock = &ktime_get_raw_fast_ns;
10719 case CLOCK_REALTIME:
10720 event->clock = &ktime_get_real_ns;
10723 case CLOCK_BOOTTIME:
10724 event->clock = &ktime_get_boottime_ns;
10728 event->clock = &ktime_get_clocktai_ns;
10735 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10742 * Variation on perf_event_ctx_lock_nested(), except we take two context
10745 static struct perf_event_context *
10746 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10747 struct perf_event_context *ctx)
10749 struct perf_event_context *gctx;
10753 gctx = READ_ONCE(group_leader->ctx);
10754 if (!refcount_inc_not_zero(&gctx->refcount)) {
10760 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10762 if (group_leader->ctx != gctx) {
10763 mutex_unlock(&ctx->mutex);
10764 mutex_unlock(&gctx->mutex);
10773 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10775 * @attr_uptr: event_id type attributes for monitoring/sampling
10778 * @group_fd: group leader event fd
10780 SYSCALL_DEFINE5(perf_event_open,
10781 struct perf_event_attr __user *, attr_uptr,
10782 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10784 struct perf_event *group_leader = NULL, *output_event = NULL;
10785 struct perf_event *event, *sibling;
10786 struct perf_event_attr attr;
10787 struct perf_event_context *ctx, *uninitialized_var(gctx);
10788 struct file *event_file = NULL;
10789 struct fd group = {NULL, 0};
10790 struct task_struct *task = NULL;
10793 int move_group = 0;
10795 int f_flags = O_RDWR;
10796 int cgroup_fd = -1;
10798 /* for future expandability... */
10799 if (flags & ~PERF_FLAG_ALL)
10802 err = perf_copy_attr(attr_uptr, &attr);
10806 if (!attr.exclude_kernel) {
10807 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10811 if (attr.namespaces) {
10812 if (!capable(CAP_SYS_ADMIN))
10817 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10820 if (attr.sample_period & (1ULL << 63))
10824 /* Only privileged users can get physical addresses */
10825 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10826 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10830 * In cgroup mode, the pid argument is used to pass the fd
10831 * opened to the cgroup directory in cgroupfs. The cpu argument
10832 * designates the cpu on which to monitor threads from that
10835 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10838 if (flags & PERF_FLAG_FD_CLOEXEC)
10839 f_flags |= O_CLOEXEC;
10841 event_fd = get_unused_fd_flags(f_flags);
10845 if (group_fd != -1) {
10846 err = perf_fget_light(group_fd, &group);
10849 group_leader = group.file->private_data;
10850 if (flags & PERF_FLAG_FD_OUTPUT)
10851 output_event = group_leader;
10852 if (flags & PERF_FLAG_FD_NO_GROUP)
10853 group_leader = NULL;
10856 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10857 task = find_lively_task_by_vpid(pid);
10858 if (IS_ERR(task)) {
10859 err = PTR_ERR(task);
10864 if (task && group_leader &&
10865 group_leader->attr.inherit != attr.inherit) {
10871 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10876 * Reuse ptrace permission checks for now.
10878 * We must hold cred_guard_mutex across this and any potential
10879 * perf_install_in_context() call for this new event to
10880 * serialize against exec() altering our credentials (and the
10881 * perf_event_exit_task() that could imply).
10884 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10888 if (flags & PERF_FLAG_PID_CGROUP)
10891 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10892 NULL, NULL, cgroup_fd);
10893 if (IS_ERR(event)) {
10894 err = PTR_ERR(event);
10898 if (is_sampling_event(event)) {
10899 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10906 * Special case software events and allow them to be part of
10907 * any hardware group.
10911 if (attr.use_clockid) {
10912 err = perf_event_set_clock(event, attr.clockid);
10917 if (pmu->task_ctx_nr == perf_sw_context)
10918 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10920 if (group_leader) {
10921 if (is_software_event(event) &&
10922 !in_software_context(group_leader)) {
10924 * If the event is a sw event, but the group_leader
10925 * is on hw context.
10927 * Allow the addition of software events to hw
10928 * groups, this is safe because software events
10929 * never fail to schedule.
10931 pmu = group_leader->ctx->pmu;
10932 } else if (!is_software_event(event) &&
10933 is_software_event(group_leader) &&
10934 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10936 * In case the group is a pure software group, and we
10937 * try to add a hardware event, move the whole group to
10938 * the hardware context.
10945 * Get the target context (task or percpu):
10947 ctx = find_get_context(pmu, task, event);
10949 err = PTR_ERR(ctx);
10954 * Look up the group leader (we will attach this event to it):
10956 if (group_leader) {
10960 * Do not allow a recursive hierarchy (this new sibling
10961 * becoming part of another group-sibling):
10963 if (group_leader->group_leader != group_leader)
10966 /* All events in a group should have the same clock */
10967 if (group_leader->clock != event->clock)
10971 * Make sure we're both events for the same CPU;
10972 * grouping events for different CPUs is broken; since
10973 * you can never concurrently schedule them anyhow.
10975 if (group_leader->cpu != event->cpu)
10979 * Make sure we're both on the same task, or both
10982 if (group_leader->ctx->task != ctx->task)
10986 * Do not allow to attach to a group in a different task
10987 * or CPU context. If we're moving SW events, we'll fix
10988 * this up later, so allow that.
10990 if (!move_group && group_leader->ctx != ctx)
10994 * Only a group leader can be exclusive or pinned
10996 if (attr.exclusive || attr.pinned)
11000 if (output_event) {
11001 err = perf_event_set_output(event, output_event);
11006 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11008 if (IS_ERR(event_file)) {
11009 err = PTR_ERR(event_file);
11015 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11017 if (gctx->task == TASK_TOMBSTONE) {
11023 * Check if we raced against another sys_perf_event_open() call
11024 * moving the software group underneath us.
11026 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11028 * If someone moved the group out from under us, check
11029 * if this new event wound up on the same ctx, if so
11030 * its the regular !move_group case, otherwise fail.
11036 perf_event_ctx_unlock(group_leader, gctx);
11042 * Failure to create exclusive events returns -EBUSY.
11045 if (!exclusive_event_installable(group_leader, ctx))
11048 for_each_sibling_event(sibling, group_leader) {
11049 if (!exclusive_event_installable(sibling, ctx))
11053 mutex_lock(&ctx->mutex);
11056 if (ctx->task == TASK_TOMBSTONE) {
11061 if (!perf_event_validate_size(event)) {
11068 * Check if the @cpu we're creating an event for is online.
11070 * We use the perf_cpu_context::ctx::mutex to serialize against
11071 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11073 struct perf_cpu_context *cpuctx =
11074 container_of(ctx, struct perf_cpu_context, ctx);
11076 if (!cpuctx->online) {
11084 * Must be under the same ctx::mutex as perf_install_in_context(),
11085 * because we need to serialize with concurrent event creation.
11087 if (!exclusive_event_installable(event, ctx)) {
11092 WARN_ON_ONCE(ctx->parent_ctx);
11095 * This is the point on no return; we cannot fail hereafter. This is
11096 * where we start modifying current state.
11101 * See perf_event_ctx_lock() for comments on the details
11102 * of swizzling perf_event::ctx.
11104 perf_remove_from_context(group_leader, 0);
11107 for_each_sibling_event(sibling, group_leader) {
11108 perf_remove_from_context(sibling, 0);
11113 * Wait for everybody to stop referencing the events through
11114 * the old lists, before installing it on new lists.
11119 * Install the group siblings before the group leader.
11121 * Because a group leader will try and install the entire group
11122 * (through the sibling list, which is still in-tact), we can
11123 * end up with siblings installed in the wrong context.
11125 * By installing siblings first we NO-OP because they're not
11126 * reachable through the group lists.
11128 for_each_sibling_event(sibling, group_leader) {
11129 perf_event__state_init(sibling);
11130 perf_install_in_context(ctx, sibling, sibling->cpu);
11135 * Removing from the context ends up with disabled
11136 * event. What we want here is event in the initial
11137 * startup state, ready to be add into new context.
11139 perf_event__state_init(group_leader);
11140 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11145 * Precalculate sample_data sizes; do while holding ctx::mutex such
11146 * that we're serialized against further additions and before
11147 * perf_install_in_context() which is the point the event is active and
11148 * can use these values.
11150 perf_event__header_size(event);
11151 perf_event__id_header_size(event);
11153 event->owner = current;
11155 perf_install_in_context(ctx, event, event->cpu);
11156 perf_unpin_context(ctx);
11159 perf_event_ctx_unlock(group_leader, gctx);
11160 mutex_unlock(&ctx->mutex);
11163 mutex_unlock(&task->signal->cred_guard_mutex);
11164 put_task_struct(task);
11167 mutex_lock(¤t->perf_event_mutex);
11168 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11169 mutex_unlock(¤t->perf_event_mutex);
11172 * Drop the reference on the group_event after placing the
11173 * new event on the sibling_list. This ensures destruction
11174 * of the group leader will find the pointer to itself in
11175 * perf_group_detach().
11178 fd_install(event_fd, event_file);
11183 perf_event_ctx_unlock(group_leader, gctx);
11184 mutex_unlock(&ctx->mutex);
11188 perf_unpin_context(ctx);
11192 * If event_file is set, the fput() above will have called ->release()
11193 * and that will take care of freeing the event.
11199 mutex_unlock(&task->signal->cred_guard_mutex);
11202 put_task_struct(task);
11206 put_unused_fd(event_fd);
11211 * perf_event_create_kernel_counter
11213 * @attr: attributes of the counter to create
11214 * @cpu: cpu in which the counter is bound
11215 * @task: task to profile (NULL for percpu)
11217 struct perf_event *
11218 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11219 struct task_struct *task,
11220 perf_overflow_handler_t overflow_handler,
11223 struct perf_event_context *ctx;
11224 struct perf_event *event;
11228 * Get the target context (task or percpu):
11231 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11232 overflow_handler, context, -1);
11233 if (IS_ERR(event)) {
11234 err = PTR_ERR(event);
11238 /* Mark owner so we could distinguish it from user events. */
11239 event->owner = TASK_TOMBSTONE;
11241 ctx = find_get_context(event->pmu, task, event);
11243 err = PTR_ERR(ctx);
11247 WARN_ON_ONCE(ctx->parent_ctx);
11248 mutex_lock(&ctx->mutex);
11249 if (ctx->task == TASK_TOMBSTONE) {
11256 * Check if the @cpu we're creating an event for is online.
11258 * We use the perf_cpu_context::ctx::mutex to serialize against
11259 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11261 struct perf_cpu_context *cpuctx =
11262 container_of(ctx, struct perf_cpu_context, ctx);
11263 if (!cpuctx->online) {
11269 if (!exclusive_event_installable(event, ctx)) {
11274 perf_install_in_context(ctx, event, event->cpu);
11275 perf_unpin_context(ctx);
11276 mutex_unlock(&ctx->mutex);
11281 mutex_unlock(&ctx->mutex);
11282 perf_unpin_context(ctx);
11287 return ERR_PTR(err);
11289 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11291 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11293 struct perf_event_context *src_ctx;
11294 struct perf_event_context *dst_ctx;
11295 struct perf_event *event, *tmp;
11298 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11299 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11302 * See perf_event_ctx_lock() for comments on the details
11303 * of swizzling perf_event::ctx.
11305 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11306 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11308 perf_remove_from_context(event, 0);
11309 unaccount_event_cpu(event, src_cpu);
11311 list_add(&event->migrate_entry, &events);
11315 * Wait for the events to quiesce before re-instating them.
11320 * Re-instate events in 2 passes.
11322 * Skip over group leaders and only install siblings on this first
11323 * pass, siblings will not get enabled without a leader, however a
11324 * leader will enable its siblings, even if those are still on the old
11327 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11328 if (event->group_leader == event)
11331 list_del(&event->migrate_entry);
11332 if (event->state >= PERF_EVENT_STATE_OFF)
11333 event->state = PERF_EVENT_STATE_INACTIVE;
11334 account_event_cpu(event, dst_cpu);
11335 perf_install_in_context(dst_ctx, event, dst_cpu);
11340 * Once all the siblings are setup properly, install the group leaders
11343 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11344 list_del(&event->migrate_entry);
11345 if (event->state >= PERF_EVENT_STATE_OFF)
11346 event->state = PERF_EVENT_STATE_INACTIVE;
11347 account_event_cpu(event, dst_cpu);
11348 perf_install_in_context(dst_ctx, event, dst_cpu);
11351 mutex_unlock(&dst_ctx->mutex);
11352 mutex_unlock(&src_ctx->mutex);
11354 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11356 static void sync_child_event(struct perf_event *child_event,
11357 struct task_struct *child)
11359 struct perf_event *parent_event = child_event->parent;
11362 if (child_event->attr.inherit_stat)
11363 perf_event_read_event(child_event, child);
11365 child_val = perf_event_count(child_event);
11368 * Add back the child's count to the parent's count:
11370 atomic64_add(child_val, &parent_event->child_count);
11371 atomic64_add(child_event->total_time_enabled,
11372 &parent_event->child_total_time_enabled);
11373 atomic64_add(child_event->total_time_running,
11374 &parent_event->child_total_time_running);
11378 perf_event_exit_event(struct perf_event *child_event,
11379 struct perf_event_context *child_ctx,
11380 struct task_struct *child)
11382 struct perf_event *parent_event = child_event->parent;
11385 * Do not destroy the 'original' grouping; because of the context
11386 * switch optimization the original events could've ended up in a
11387 * random child task.
11389 * If we were to destroy the original group, all group related
11390 * operations would cease to function properly after this random
11393 * Do destroy all inherited groups, we don't care about those
11394 * and being thorough is better.
11396 raw_spin_lock_irq(&child_ctx->lock);
11397 WARN_ON_ONCE(child_ctx->is_active);
11400 perf_group_detach(child_event);
11401 list_del_event(child_event, child_ctx);
11402 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11403 raw_spin_unlock_irq(&child_ctx->lock);
11406 * Parent events are governed by their filedesc, retain them.
11408 if (!parent_event) {
11409 perf_event_wakeup(child_event);
11413 * Child events can be cleaned up.
11416 sync_child_event(child_event, child);
11419 * Remove this event from the parent's list
11421 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11422 mutex_lock(&parent_event->child_mutex);
11423 list_del_init(&child_event->child_list);
11424 mutex_unlock(&parent_event->child_mutex);
11427 * Kick perf_poll() for is_event_hup().
11429 perf_event_wakeup(parent_event);
11430 free_event(child_event);
11431 put_event(parent_event);
11434 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11436 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11437 struct perf_event *child_event, *next;
11439 WARN_ON_ONCE(child != current);
11441 child_ctx = perf_pin_task_context(child, ctxn);
11446 * In order to reduce the amount of tricky in ctx tear-down, we hold
11447 * ctx::mutex over the entire thing. This serializes against almost
11448 * everything that wants to access the ctx.
11450 * The exception is sys_perf_event_open() /
11451 * perf_event_create_kernel_count() which does find_get_context()
11452 * without ctx::mutex (it cannot because of the move_group double mutex
11453 * lock thing). See the comments in perf_install_in_context().
11455 mutex_lock(&child_ctx->mutex);
11458 * In a single ctx::lock section, de-schedule the events and detach the
11459 * context from the task such that we cannot ever get it scheduled back
11462 raw_spin_lock_irq(&child_ctx->lock);
11463 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11466 * Now that the context is inactive, destroy the task <-> ctx relation
11467 * and mark the context dead.
11469 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11470 put_ctx(child_ctx); /* cannot be last */
11471 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11472 put_task_struct(current); /* cannot be last */
11474 clone_ctx = unclone_ctx(child_ctx);
11475 raw_spin_unlock_irq(&child_ctx->lock);
11478 put_ctx(clone_ctx);
11481 * Report the task dead after unscheduling the events so that we
11482 * won't get any samples after PERF_RECORD_EXIT. We can however still
11483 * get a few PERF_RECORD_READ events.
11485 perf_event_task(child, child_ctx, 0);
11487 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11488 perf_event_exit_event(child_event, child_ctx, child);
11490 mutex_unlock(&child_ctx->mutex);
11492 put_ctx(child_ctx);
11496 * When a child task exits, feed back event values to parent events.
11498 * Can be called with cred_guard_mutex held when called from
11499 * install_exec_creds().
11501 void perf_event_exit_task(struct task_struct *child)
11503 struct perf_event *event, *tmp;
11506 mutex_lock(&child->perf_event_mutex);
11507 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11509 list_del_init(&event->owner_entry);
11512 * Ensure the list deletion is visible before we clear
11513 * the owner, closes a race against perf_release() where
11514 * we need to serialize on the owner->perf_event_mutex.
11516 smp_store_release(&event->owner, NULL);
11518 mutex_unlock(&child->perf_event_mutex);
11520 for_each_task_context_nr(ctxn)
11521 perf_event_exit_task_context(child, ctxn);
11524 * The perf_event_exit_task_context calls perf_event_task
11525 * with child's task_ctx, which generates EXIT events for
11526 * child contexts and sets child->perf_event_ctxp[] to NULL.
11527 * At this point we need to send EXIT events to cpu contexts.
11529 perf_event_task(child, NULL, 0);
11532 static void perf_free_event(struct perf_event *event,
11533 struct perf_event_context *ctx)
11535 struct perf_event *parent = event->parent;
11537 if (WARN_ON_ONCE(!parent))
11540 mutex_lock(&parent->child_mutex);
11541 list_del_init(&event->child_list);
11542 mutex_unlock(&parent->child_mutex);
11546 raw_spin_lock_irq(&ctx->lock);
11547 perf_group_detach(event);
11548 list_del_event(event, ctx);
11549 raw_spin_unlock_irq(&ctx->lock);
11554 * Free a context as created by inheritance by perf_event_init_task() below,
11555 * used by fork() in case of fail.
11557 * Even though the task has never lived, the context and events have been
11558 * exposed through the child_list, so we must take care tearing it all down.
11560 void perf_event_free_task(struct task_struct *task)
11562 struct perf_event_context *ctx;
11563 struct perf_event *event, *tmp;
11566 for_each_task_context_nr(ctxn) {
11567 ctx = task->perf_event_ctxp[ctxn];
11571 mutex_lock(&ctx->mutex);
11572 raw_spin_lock_irq(&ctx->lock);
11574 * Destroy the task <-> ctx relation and mark the context dead.
11576 * This is important because even though the task hasn't been
11577 * exposed yet the context has been (through child_list).
11579 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11580 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11581 put_task_struct(task); /* cannot be last */
11582 raw_spin_unlock_irq(&ctx->lock);
11584 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11585 perf_free_event(event, ctx);
11587 mutex_unlock(&ctx->mutex);
11590 * perf_event_release_kernel() could've stolen some of our
11591 * child events and still have them on its free_list. In that
11592 * case we must wait for these events to have been freed (in
11593 * particular all their references to this task must've been
11596 * Without this copy_process() will unconditionally free this
11597 * task (irrespective of its reference count) and
11598 * _free_event()'s put_task_struct(event->hw.target) will be a
11601 * Wait for all events to drop their context reference.
11603 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
11604 put_ctx(ctx); /* must be last */
11608 void perf_event_delayed_put(struct task_struct *task)
11612 for_each_task_context_nr(ctxn)
11613 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11616 struct file *perf_event_get(unsigned int fd)
11618 struct file *file = fget(fd);
11620 return ERR_PTR(-EBADF);
11622 if (file->f_op != &perf_fops) {
11624 return ERR_PTR(-EBADF);
11630 const struct perf_event *perf_get_event(struct file *file)
11632 if (file->f_op != &perf_fops)
11633 return ERR_PTR(-EINVAL);
11635 return file->private_data;
11638 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11641 return ERR_PTR(-EINVAL);
11643 return &event->attr;
11647 * Inherit an event from parent task to child task.
11650 * - valid pointer on success
11651 * - NULL for orphaned events
11652 * - IS_ERR() on error
11654 static struct perf_event *
11655 inherit_event(struct perf_event *parent_event,
11656 struct task_struct *parent,
11657 struct perf_event_context *parent_ctx,
11658 struct task_struct *child,
11659 struct perf_event *group_leader,
11660 struct perf_event_context *child_ctx)
11662 enum perf_event_state parent_state = parent_event->state;
11663 struct perf_event *child_event;
11664 unsigned long flags;
11667 * Instead of creating recursive hierarchies of events,
11668 * we link inherited events back to the original parent,
11669 * which has a filp for sure, which we use as the reference
11672 if (parent_event->parent)
11673 parent_event = parent_event->parent;
11675 child_event = perf_event_alloc(&parent_event->attr,
11678 group_leader, parent_event,
11680 if (IS_ERR(child_event))
11681 return child_event;
11684 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11685 !child_ctx->task_ctx_data) {
11686 struct pmu *pmu = child_event->pmu;
11688 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11690 if (!child_ctx->task_ctx_data) {
11691 free_event(child_event);
11697 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11698 * must be under the same lock in order to serialize against
11699 * perf_event_release_kernel(), such that either we must observe
11700 * is_orphaned_event() or they will observe us on the child_list.
11702 mutex_lock(&parent_event->child_mutex);
11703 if (is_orphaned_event(parent_event) ||
11704 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11705 mutex_unlock(&parent_event->child_mutex);
11706 /* task_ctx_data is freed with child_ctx */
11707 free_event(child_event);
11711 get_ctx(child_ctx);
11714 * Make the child state follow the state of the parent event,
11715 * not its attr.disabled bit. We hold the parent's mutex,
11716 * so we won't race with perf_event_{en, dis}able_family.
11718 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11719 child_event->state = PERF_EVENT_STATE_INACTIVE;
11721 child_event->state = PERF_EVENT_STATE_OFF;
11723 if (parent_event->attr.freq) {
11724 u64 sample_period = parent_event->hw.sample_period;
11725 struct hw_perf_event *hwc = &child_event->hw;
11727 hwc->sample_period = sample_period;
11728 hwc->last_period = sample_period;
11730 local64_set(&hwc->period_left, sample_period);
11733 child_event->ctx = child_ctx;
11734 child_event->overflow_handler = parent_event->overflow_handler;
11735 child_event->overflow_handler_context
11736 = parent_event->overflow_handler_context;
11739 * Precalculate sample_data sizes
11741 perf_event__header_size(child_event);
11742 perf_event__id_header_size(child_event);
11745 * Link it up in the child's context:
11747 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11748 add_event_to_ctx(child_event, child_ctx);
11749 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11752 * Link this into the parent event's child list
11754 list_add_tail(&child_event->child_list, &parent_event->child_list);
11755 mutex_unlock(&parent_event->child_mutex);
11757 return child_event;
11761 * Inherits an event group.
11763 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11764 * This matches with perf_event_release_kernel() removing all child events.
11770 static int inherit_group(struct perf_event *parent_event,
11771 struct task_struct *parent,
11772 struct perf_event_context *parent_ctx,
11773 struct task_struct *child,
11774 struct perf_event_context *child_ctx)
11776 struct perf_event *leader;
11777 struct perf_event *sub;
11778 struct perf_event *child_ctr;
11780 leader = inherit_event(parent_event, parent, parent_ctx,
11781 child, NULL, child_ctx);
11782 if (IS_ERR(leader))
11783 return PTR_ERR(leader);
11785 * @leader can be NULL here because of is_orphaned_event(). In this
11786 * case inherit_event() will create individual events, similar to what
11787 * perf_group_detach() would do anyway.
11789 for_each_sibling_event(sub, parent_event) {
11790 child_ctr = inherit_event(sub, parent, parent_ctx,
11791 child, leader, child_ctx);
11792 if (IS_ERR(child_ctr))
11793 return PTR_ERR(child_ctr);
11799 * Creates the child task context and tries to inherit the event-group.
11801 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11802 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11803 * consistent with perf_event_release_kernel() removing all child events.
11810 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11811 struct perf_event_context *parent_ctx,
11812 struct task_struct *child, int ctxn,
11813 int *inherited_all)
11816 struct perf_event_context *child_ctx;
11818 if (!event->attr.inherit) {
11819 *inherited_all = 0;
11823 child_ctx = child->perf_event_ctxp[ctxn];
11826 * This is executed from the parent task context, so
11827 * inherit events that have been marked for cloning.
11828 * First allocate and initialize a context for the
11831 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11835 child->perf_event_ctxp[ctxn] = child_ctx;
11838 ret = inherit_group(event, parent, parent_ctx,
11842 *inherited_all = 0;
11848 * Initialize the perf_event context in task_struct
11850 static int perf_event_init_context(struct task_struct *child, int ctxn)
11852 struct perf_event_context *child_ctx, *parent_ctx;
11853 struct perf_event_context *cloned_ctx;
11854 struct perf_event *event;
11855 struct task_struct *parent = current;
11856 int inherited_all = 1;
11857 unsigned long flags;
11860 if (likely(!parent->perf_event_ctxp[ctxn]))
11864 * If the parent's context is a clone, pin it so it won't get
11865 * swapped under us.
11867 parent_ctx = perf_pin_task_context(parent, ctxn);
11872 * No need to check if parent_ctx != NULL here; since we saw
11873 * it non-NULL earlier, the only reason for it to become NULL
11874 * is if we exit, and since we're currently in the middle of
11875 * a fork we can't be exiting at the same time.
11879 * Lock the parent list. No need to lock the child - not PID
11880 * hashed yet and not running, so nobody can access it.
11882 mutex_lock(&parent_ctx->mutex);
11885 * We dont have to disable NMIs - we are only looking at
11886 * the list, not manipulating it:
11888 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11889 ret = inherit_task_group(event, parent, parent_ctx,
11890 child, ctxn, &inherited_all);
11896 * We can't hold ctx->lock when iterating the ->flexible_group list due
11897 * to allocations, but we need to prevent rotation because
11898 * rotate_ctx() will change the list from interrupt context.
11900 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11901 parent_ctx->rotate_disable = 1;
11902 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11904 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11905 ret = inherit_task_group(event, parent, parent_ctx,
11906 child, ctxn, &inherited_all);
11911 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11912 parent_ctx->rotate_disable = 0;
11914 child_ctx = child->perf_event_ctxp[ctxn];
11916 if (child_ctx && inherited_all) {
11918 * Mark the child context as a clone of the parent
11919 * context, or of whatever the parent is a clone of.
11921 * Note that if the parent is a clone, the holding of
11922 * parent_ctx->lock avoids it from being uncloned.
11924 cloned_ctx = parent_ctx->parent_ctx;
11926 child_ctx->parent_ctx = cloned_ctx;
11927 child_ctx->parent_gen = parent_ctx->parent_gen;
11929 child_ctx->parent_ctx = parent_ctx;
11930 child_ctx->parent_gen = parent_ctx->generation;
11932 get_ctx(child_ctx->parent_ctx);
11935 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11937 mutex_unlock(&parent_ctx->mutex);
11939 perf_unpin_context(parent_ctx);
11940 put_ctx(parent_ctx);
11946 * Initialize the perf_event context in task_struct
11948 int perf_event_init_task(struct task_struct *child)
11952 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11953 mutex_init(&child->perf_event_mutex);
11954 INIT_LIST_HEAD(&child->perf_event_list);
11956 for_each_task_context_nr(ctxn) {
11957 ret = perf_event_init_context(child, ctxn);
11959 perf_event_free_task(child);
11967 static void __init perf_event_init_all_cpus(void)
11969 struct swevent_htable *swhash;
11972 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11974 for_each_possible_cpu(cpu) {
11975 swhash = &per_cpu(swevent_htable, cpu);
11976 mutex_init(&swhash->hlist_mutex);
11977 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11979 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11980 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11982 #ifdef CONFIG_CGROUP_PERF
11983 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11985 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11989 static void perf_swevent_init_cpu(unsigned int cpu)
11991 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11993 mutex_lock(&swhash->hlist_mutex);
11994 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11995 struct swevent_hlist *hlist;
11997 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11999 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12001 mutex_unlock(&swhash->hlist_mutex);
12004 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12005 static void __perf_event_exit_context(void *__info)
12007 struct perf_event_context *ctx = __info;
12008 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12009 struct perf_event *event;
12011 raw_spin_lock(&ctx->lock);
12012 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12013 list_for_each_entry(event, &ctx->event_list, event_entry)
12014 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12015 raw_spin_unlock(&ctx->lock);
12018 static void perf_event_exit_cpu_context(int cpu)
12020 struct perf_cpu_context *cpuctx;
12021 struct perf_event_context *ctx;
12024 mutex_lock(&pmus_lock);
12025 list_for_each_entry(pmu, &pmus, entry) {
12026 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12027 ctx = &cpuctx->ctx;
12029 mutex_lock(&ctx->mutex);
12030 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12031 cpuctx->online = 0;
12032 mutex_unlock(&ctx->mutex);
12034 cpumask_clear_cpu(cpu, perf_online_mask);
12035 mutex_unlock(&pmus_lock);
12039 static void perf_event_exit_cpu_context(int cpu) { }
12043 int perf_event_init_cpu(unsigned int cpu)
12045 struct perf_cpu_context *cpuctx;
12046 struct perf_event_context *ctx;
12049 perf_swevent_init_cpu(cpu);
12051 mutex_lock(&pmus_lock);
12052 cpumask_set_cpu(cpu, perf_online_mask);
12053 list_for_each_entry(pmu, &pmus, entry) {
12054 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12055 ctx = &cpuctx->ctx;
12057 mutex_lock(&ctx->mutex);
12058 cpuctx->online = 1;
12059 mutex_unlock(&ctx->mutex);
12061 mutex_unlock(&pmus_lock);
12066 int perf_event_exit_cpu(unsigned int cpu)
12068 perf_event_exit_cpu_context(cpu);
12073 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12077 for_each_online_cpu(cpu)
12078 perf_event_exit_cpu(cpu);
12084 * Run the perf reboot notifier at the very last possible moment so that
12085 * the generic watchdog code runs as long as possible.
12087 static struct notifier_block perf_reboot_notifier = {
12088 .notifier_call = perf_reboot,
12089 .priority = INT_MIN,
12092 void __init perf_event_init(void)
12096 idr_init(&pmu_idr);
12098 perf_event_init_all_cpus();
12099 init_srcu_struct(&pmus_srcu);
12100 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12101 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12102 perf_pmu_register(&perf_task_clock, NULL, -1);
12103 perf_tp_register();
12104 perf_event_init_cpu(smp_processor_id());
12105 register_reboot_notifier(&perf_reboot_notifier);
12107 ret = init_hw_breakpoint();
12108 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12111 * Build time assertion that we keep the data_head at the intended
12112 * location. IOW, validation we got the __reserved[] size right.
12114 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12118 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12121 struct perf_pmu_events_attr *pmu_attr =
12122 container_of(attr, struct perf_pmu_events_attr, attr);
12124 if (pmu_attr->event_str)
12125 return sprintf(page, "%s\n", pmu_attr->event_str);
12129 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12131 static int __init perf_event_sysfs_init(void)
12136 mutex_lock(&pmus_lock);
12138 ret = bus_register(&pmu_bus);
12142 list_for_each_entry(pmu, &pmus, entry) {
12143 if (!pmu->name || pmu->type < 0)
12146 ret = pmu_dev_alloc(pmu);
12147 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12149 pmu_bus_running = 1;
12153 mutex_unlock(&pmus_lock);
12157 device_initcall(perf_event_sysfs_init);
12159 #ifdef CONFIG_CGROUP_PERF
12160 static struct cgroup_subsys_state *
12161 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12163 struct perf_cgroup *jc;
12165 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12167 return ERR_PTR(-ENOMEM);
12169 jc->info = alloc_percpu(struct perf_cgroup_info);
12172 return ERR_PTR(-ENOMEM);
12178 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12180 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12182 free_percpu(jc->info);
12186 static int __perf_cgroup_move(void *info)
12188 struct task_struct *task = info;
12190 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12195 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12197 struct task_struct *task;
12198 struct cgroup_subsys_state *css;
12200 cgroup_taskset_for_each(task, css, tset)
12201 task_function_call(task, __perf_cgroup_move, task);
12204 struct cgroup_subsys perf_event_cgrp_subsys = {
12205 .css_alloc = perf_cgroup_css_alloc,
12206 .css_free = perf_cgroup_css_free,
12207 .attach = perf_cgroup_attach,
12209 * Implicitly enable on dfl hierarchy so that perf events can
12210 * always be filtered by cgroup2 path as long as perf_event
12211 * controller is not mounted on a legacy hierarchy.
12213 .implicit_on_dfl = true,
12216 #endif /* CONFIG_CGROUP_PERF */