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-rw-r--r--kernel/perf_event.c5174
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diff --git a/kernel/perf_event.c b/kernel/perf_event.c
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1/*
2 * Performance events core code:
3 *
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
8 *
9 * For licensing details see kernel-base/COPYING
10 */
11
12#include <linux/fs.h>
13#include <linux/mm.h>
14#include <linux/cpu.h>
15#include <linux/smp.h>
16#include <linux/file.h>
17#include <linux/poll.h>
18#include <linux/sysfs.h>
19#include <linux/dcache.h>
20#include <linux/percpu.h>
21#include <linux/ptrace.h>
22#include <linux/vmstat.h>
23#include <linux/vmalloc.h>
24#include <linux/hardirq.h>
25#include <linux/rculist.h>
26#include <linux/uaccess.h>
27#include <linux/syscalls.h>
28#include <linux/anon_inodes.h>
29#include <linux/kernel_stat.h>
30#include <linux/perf_event.h>
31#include <linux/ftrace_event.h>
32
33#include <asm/irq_regs.h>
34
35/*
36 * Each CPU has a list of per CPU events:
37 */
38DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
39
40int perf_max_events __read_mostly = 1;
41static int perf_reserved_percpu __read_mostly;
42static int perf_overcommit __read_mostly = 1;
43
44static atomic_t nr_events __read_mostly;
45static atomic_t nr_mmap_events __read_mostly;
46static atomic_t nr_comm_events __read_mostly;
47static atomic_t nr_task_events __read_mostly;
48
49/*
50 * perf event paranoia level:
51 * -1 - not paranoid at all
52 * 0 - disallow raw tracepoint access for unpriv
53 * 1 - disallow cpu events for unpriv
54 * 2 - disallow kernel profiling for unpriv
55 */
56int sysctl_perf_event_paranoid __read_mostly = 1;
57
58static inline bool perf_paranoid_tracepoint_raw(void)
59{
60 return sysctl_perf_event_paranoid > -1;
61}
62
63static inline bool perf_paranoid_cpu(void)
64{
65 return sysctl_perf_event_paranoid > 0;
66}
67
68static inline bool perf_paranoid_kernel(void)
69{
70 return sysctl_perf_event_paranoid > 1;
71}
72
73int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */
74
75/*
76 * max perf event sample rate
77 */
78int sysctl_perf_event_sample_rate __read_mostly = 100000;
79
80static atomic64_t perf_event_id;
81
82/*
83 * Lock for (sysadmin-configurable) event reservations:
84 */
85static DEFINE_SPINLOCK(perf_resource_lock);
86
87/*
88 * Architecture provided APIs - weak aliases:
89 */
90extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event)
91{
92 return NULL;
93}
94
95void __weak hw_perf_disable(void) { barrier(); }
96void __weak hw_perf_enable(void) { barrier(); }
97
98void __weak hw_perf_event_setup(int cpu) { barrier(); }
99void __weak hw_perf_event_setup_online(int cpu) { barrier(); }
100
101int __weak
102hw_perf_group_sched_in(struct perf_event *group_leader,
103 struct perf_cpu_context *cpuctx,
104 struct perf_event_context *ctx, int cpu)
105{
106 return 0;
107}
108
109void __weak perf_event_print_debug(void) { }
110
111static DEFINE_PER_CPU(int, perf_disable_count);
112
113void __perf_disable(void)
114{
115 __get_cpu_var(perf_disable_count)++;
116}
117
118bool __perf_enable(void)
119{
120 return !--__get_cpu_var(perf_disable_count);
121}
122
123void perf_disable(void)
124{
125 __perf_disable();
126 hw_perf_disable();
127}
128
129void perf_enable(void)
130{
131 if (__perf_enable())
132 hw_perf_enable();
133}
134
135static void get_ctx(struct perf_event_context *ctx)
136{
137 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
138}
139
140static void free_ctx(struct rcu_head *head)
141{
142 struct perf_event_context *ctx;
143
144 ctx = container_of(head, struct perf_event_context, rcu_head);
145 kfree(ctx);
146}
147
148static void put_ctx(struct perf_event_context *ctx)
149{
150 if (atomic_dec_and_test(&ctx->refcount)) {
151 if (ctx->parent_ctx)
152 put_ctx(ctx->parent_ctx);
153 if (ctx->task)
154 put_task_struct(ctx->task);
155 call_rcu(&ctx->rcu_head, free_ctx);
156 }
157}
158
159static void unclone_ctx(struct perf_event_context *ctx)
160{
161 if (ctx->parent_ctx) {
162 put_ctx(ctx->parent_ctx);
163 ctx->parent_ctx = NULL;
164 }
165}
166
167/*
168 * If we inherit events we want to return the parent event id
169 * to userspace.
170 */
171static u64 primary_event_id(struct perf_event *event)
172{
173 u64 id = event->id;
174
175 if (event->parent)
176 id = event->parent->id;
177
178 return id;
179}
180
181/*
182 * Get the perf_event_context for a task and lock it.
183 * This has to cope with with the fact that until it is locked,
184 * the context could get moved to another task.
185 */
186static struct perf_event_context *
187perf_lock_task_context(struct task_struct *task, unsigned long *flags)
188{
189 struct perf_event_context *ctx;
190
191 rcu_read_lock();
192 retry:
193 ctx = rcu_dereference(task->perf_event_ctxp);
194 if (ctx) {
195 /*
196 * If this context is a clone of another, it might
197 * get swapped for another underneath us by
198 * perf_event_task_sched_out, though the
199 * rcu_read_lock() protects us from any context
200 * getting freed. Lock the context and check if it
201 * got swapped before we could get the lock, and retry
202 * if so. If we locked the right context, then it
203 * can't get swapped on us any more.
204 */
205 spin_lock_irqsave(&ctx->lock, *flags);
206 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
207 spin_unlock_irqrestore(&ctx->lock, *flags);
208 goto retry;
209 }
210
211 if (!atomic_inc_not_zero(&ctx->refcount)) {
212 spin_unlock_irqrestore(&ctx->lock, *flags);
213 ctx = NULL;
214 }
215 }
216 rcu_read_unlock();
217 return ctx;
218}
219
220/*
221 * Get the context for a task and increment its pin_count so it
222 * can't get swapped to another task. This also increments its
223 * reference count so that the context can't get freed.
224 */
225static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
226{
227 struct perf_event_context *ctx;
228 unsigned long flags;
229
230 ctx = perf_lock_task_context(task, &flags);
231 if (ctx) {
232 ++ctx->pin_count;
233 spin_unlock_irqrestore(&ctx->lock, flags);
234 }
235 return ctx;
236}
237
238static void perf_unpin_context(struct perf_event_context *ctx)
239{
240 unsigned long flags;
241
242 spin_lock_irqsave(&ctx->lock, flags);
243 --ctx->pin_count;
244 spin_unlock_irqrestore(&ctx->lock, flags);
245 put_ctx(ctx);
246}
247
248/*
249 * Add a event from the lists for its context.
250 * Must be called with ctx->mutex and ctx->lock held.
251 */
252static void
253list_add_event(struct perf_event *event, struct perf_event_context *ctx)
254{
255 struct perf_event *group_leader = event->group_leader;
256
257 /*
258 * Depending on whether it is a standalone or sibling event,
259 * add it straight to the context's event list, or to the group
260 * leader's sibling list:
261 */
262 if (group_leader == event)
263 list_add_tail(&event->group_entry, &ctx->group_list);
264 else {
265 list_add_tail(&event->group_entry, &group_leader->sibling_list);
266 group_leader->nr_siblings++;
267 }
268
269 list_add_rcu(&event->event_entry, &ctx->event_list);
270 ctx->nr_events++;
271 if (event->attr.inherit_stat)
272 ctx->nr_stat++;
273}
274
275/*
276 * Remove a event from the lists for its context.
277 * Must be called with ctx->mutex and ctx->lock held.
278 */
279static void
280list_del_event(struct perf_event *event, struct perf_event_context *ctx)
281{
282 struct perf_event *sibling, *tmp;
283
284 if (list_empty(&event->group_entry))
285 return;
286 ctx->nr_events--;
287 if (event->attr.inherit_stat)
288 ctx->nr_stat--;
289
290 list_del_init(&event->group_entry);
291 list_del_rcu(&event->event_entry);
292
293 if (event->group_leader != event)
294 event->group_leader->nr_siblings--;
295
296 /*
297 * If this was a group event with sibling events then
298 * upgrade the siblings to singleton events by adding them
299 * to the context list directly:
300 */
301 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
302
303 list_move_tail(&sibling->group_entry, &ctx->group_list);
304 sibling->group_leader = sibling;
305 }
306}
307
308static void
309event_sched_out(struct perf_event *event,
310 struct perf_cpu_context *cpuctx,
311 struct perf_event_context *ctx)
312{
313 if (event->state != PERF_EVENT_STATE_ACTIVE)
314 return;
315
316 event->state = PERF_EVENT_STATE_INACTIVE;
317 if (event->pending_disable) {
318 event->pending_disable = 0;
319 event->state = PERF_EVENT_STATE_OFF;
320 }
321 event->tstamp_stopped = ctx->time;
322 event->pmu->disable(event);
323 event->oncpu = -1;
324
325 if (!is_software_event(event))
326 cpuctx->active_oncpu--;
327 ctx->nr_active--;
328 if (event->attr.exclusive || !cpuctx->active_oncpu)
329 cpuctx->exclusive = 0;
330}
331
332static void
333group_sched_out(struct perf_event *group_event,
334 struct perf_cpu_context *cpuctx,
335 struct perf_event_context *ctx)
336{
337 struct perf_event *event;
338
339 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
340 return;
341
342 event_sched_out(group_event, cpuctx, ctx);
343
344 /*
345 * Schedule out siblings (if any):
346 */
347 list_for_each_entry(event, &group_event->sibling_list, group_entry)
348 event_sched_out(event, cpuctx, ctx);
349
350 if (group_event->attr.exclusive)
351 cpuctx->exclusive = 0;
352}
353
354/*
355 * Cross CPU call to remove a performance event
356 *
357 * We disable the event on the hardware level first. After that we
358 * remove it from the context list.
359 */
360static void __perf_event_remove_from_context(void *info)
361{
362 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
363 struct perf_event *event = info;
364 struct perf_event_context *ctx = event->ctx;
365
366 /*
367 * If this is a task context, we need to check whether it is
368 * the current task context of this cpu. If not it has been
369 * scheduled out before the smp call arrived.
370 */
371 if (ctx->task && cpuctx->task_ctx != ctx)
372 return;
373
374 spin_lock(&ctx->lock);
375 /*
376 * Protect the list operation against NMI by disabling the
377 * events on a global level.
378 */
379 perf_disable();
380
381 event_sched_out(event, cpuctx, ctx);
382
383 list_del_event(event, ctx);
384
385 if (!ctx->task) {
386 /*
387 * Allow more per task events with respect to the
388 * reservation:
389 */
390 cpuctx->max_pertask =
391 min(perf_max_events - ctx->nr_events,
392 perf_max_events - perf_reserved_percpu);
393 }
394
395 perf_enable();
396 spin_unlock(&ctx->lock);
397}
398
399
400/*
401 * Remove the event from a task's (or a CPU's) list of events.
402 *
403 * Must be called with ctx->mutex held.
404 *
405 * CPU events are removed with a smp call. For task events we only
406 * call when the task is on a CPU.
407 *
408 * If event->ctx is a cloned context, callers must make sure that
409 * every task struct that event->ctx->task could possibly point to
410 * remains valid. This is OK when called from perf_release since
411 * that only calls us on the top-level context, which can't be a clone.
412 * When called from perf_event_exit_task, it's OK because the
413 * context has been detached from its task.
414 */
415static void perf_event_remove_from_context(struct perf_event *event)
416{
417 struct perf_event_context *ctx = event->ctx;
418 struct task_struct *task = ctx->task;
419
420 if (!task) {
421 /*
422 * Per cpu events are removed via an smp call and
423 * the removal is always sucessful.
424 */
425 smp_call_function_single(event->cpu,
426 __perf_event_remove_from_context,
427 event, 1);
428 return;
429 }
430
431retry:
432 task_oncpu_function_call(task, __perf_event_remove_from_context,
433 event);
434
435 spin_lock_irq(&ctx->lock);
436 /*
437 * If the context is active we need to retry the smp call.
438 */
439 if (ctx->nr_active && !list_empty(&event->group_entry)) {
440 spin_unlock_irq(&ctx->lock);
441 goto retry;
442 }
443
444 /*
445 * The lock prevents that this context is scheduled in so we
446 * can remove the event safely, if the call above did not
447 * succeed.
448 */
449 if (!list_empty(&event->group_entry)) {
450 list_del_event(event, ctx);
451 }
452 spin_unlock_irq(&ctx->lock);
453}
454
455static inline u64 perf_clock(void)
456{
457 return cpu_clock(smp_processor_id());
458}
459
460/*
461 * Update the record of the current time in a context.
462 */
463static void update_context_time(struct perf_event_context *ctx)
464{
465 u64 now = perf_clock();
466
467 ctx->time += now - ctx->timestamp;
468 ctx->timestamp = now;
469}
470
471/*
472 * Update the total_time_enabled and total_time_running fields for a event.
473 */
474static void update_event_times(struct perf_event *event)
475{
476 struct perf_event_context *ctx = event->ctx;
477 u64 run_end;
478
479 if (event->state < PERF_EVENT_STATE_INACTIVE ||
480 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
481 return;
482
483 event->total_time_enabled = ctx->time - event->tstamp_enabled;
484
485 if (event->state == PERF_EVENT_STATE_INACTIVE)
486 run_end = event->tstamp_stopped;
487 else
488 run_end = ctx->time;
489
490 event->total_time_running = run_end - event->tstamp_running;
491}
492
493/*
494 * Update total_time_enabled and total_time_running for all events in a group.
495 */
496static void update_group_times(struct perf_event *leader)
497{
498 struct perf_event *event;
499
500 update_event_times(leader);
501 list_for_each_entry(event, &leader->sibling_list, group_entry)
502 update_event_times(event);
503}
504
505/*
506 * Cross CPU call to disable a performance event
507 */
508static void __perf_event_disable(void *info)
509{
510 struct perf_event *event = info;
511 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
512 struct perf_event_context *ctx = event->ctx;
513
514 /*
515 * If this is a per-task event, need to check whether this
516 * event's task is the current task on this cpu.
517 */
518 if (ctx->task && cpuctx->task_ctx != ctx)
519 return;
520
521 spin_lock(&ctx->lock);
522
523 /*
524 * If the event is on, turn it off.
525 * If it is in error state, leave it in error state.
526 */
527 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
528 update_context_time(ctx);
529 update_group_times(event);
530 if (event == event->group_leader)
531 group_sched_out(event, cpuctx, ctx);
532 else
533 event_sched_out(event, cpuctx, ctx);
534 event->state = PERF_EVENT_STATE_OFF;
535 }
536
537 spin_unlock(&ctx->lock);
538}
539
540/*
541 * Disable a event.
542 *
543 * If event->ctx is a cloned context, callers must make sure that
544 * every task struct that event->ctx->task could possibly point to
545 * remains valid. This condition is satisifed when called through
546 * perf_event_for_each_child or perf_event_for_each because they
547 * hold the top-level event's child_mutex, so any descendant that
548 * goes to exit will block in sync_child_event.
549 * When called from perf_pending_event it's OK because event->ctx
550 * is the current context on this CPU and preemption is disabled,
551 * hence we can't get into perf_event_task_sched_out for this context.
552 */
553static void perf_event_disable(struct perf_event *event)
554{
555 struct perf_event_context *ctx = event->ctx;
556 struct task_struct *task = ctx->task;
557
558 if (!task) {
559 /*
560 * Disable the event on the cpu that it's on
561 */
562 smp_call_function_single(event->cpu, __perf_event_disable,
563 event, 1);
564 return;
565 }
566
567 retry:
568 task_oncpu_function_call(task, __perf_event_disable, event);
569
570 spin_lock_irq(&ctx->lock);
571 /*
572 * If the event is still active, we need to retry the cross-call.
573 */
574 if (event->state == PERF_EVENT_STATE_ACTIVE) {
575 spin_unlock_irq(&ctx->lock);
576 goto retry;
577 }
578
579 /*
580 * Since we have the lock this context can't be scheduled
581 * in, so we can change the state safely.
582 */
583 if (event->state == PERF_EVENT_STATE_INACTIVE) {
584 update_group_times(event);
585 event->state = PERF_EVENT_STATE_OFF;
586 }
587
588 spin_unlock_irq(&ctx->lock);
589}
590
591static int
592event_sched_in(struct perf_event *event,
593 struct perf_cpu_context *cpuctx,
594 struct perf_event_context *ctx,
595 int cpu)
596{
597 if (event->state <= PERF_EVENT_STATE_OFF)
598 return 0;
599
600 event->state = PERF_EVENT_STATE_ACTIVE;
601 event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
602 /*
603 * The new state must be visible before we turn it on in the hardware:
604 */
605 smp_wmb();
606
607 if (event->pmu->enable(event)) {
608 event->state = PERF_EVENT_STATE_INACTIVE;
609 event->oncpu = -1;
610 return -EAGAIN;
611 }
612
613 event->tstamp_running += ctx->time - event->tstamp_stopped;
614
615 if (!is_software_event(event))
616 cpuctx->active_oncpu++;
617 ctx->nr_active++;
618
619 if (event->attr.exclusive)
620 cpuctx->exclusive = 1;
621
622 return 0;
623}
624
625static int
626group_sched_in(struct perf_event *group_event,
627 struct perf_cpu_context *cpuctx,
628 struct perf_event_context *ctx,
629 int cpu)
630{
631 struct perf_event *event, *partial_group;
632 int ret;
633
634 if (group_event->state == PERF_EVENT_STATE_OFF)
635 return 0;
636
637 ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu);
638 if (ret)
639 return ret < 0 ? ret : 0;
640
641 if (event_sched_in(group_event, cpuctx, ctx, cpu))
642 return -EAGAIN;
643
644 /*
645 * Schedule in siblings as one group (if any):
646 */
647 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
648 if (event_sched_in(event, cpuctx, ctx, cpu)) {
649 partial_group = event;
650 goto group_error;
651 }
652 }
653
654 return 0;
655
656group_error:
657 /*
658 * Groups can be scheduled in as one unit only, so undo any
659 * partial group before returning:
660 */
661 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
662 if (event == partial_group)
663 break;
664 event_sched_out(event, cpuctx, ctx);
665 }
666 event_sched_out(group_event, cpuctx, ctx);
667
668 return -EAGAIN;
669}
670
671/*
672 * Return 1 for a group consisting entirely of software events,
673 * 0 if the group contains any hardware events.
674 */
675static int is_software_only_group(struct perf_event *leader)
676{
677 struct perf_event *event;
678
679 if (!is_software_event(leader))
680 return 0;
681
682 list_for_each_entry(event, &leader->sibling_list, group_entry)
683 if (!is_software_event(event))
684 return 0;
685
686 return 1;
687}
688
689/*
690 * Work out whether we can put this event group on the CPU now.
691 */
692static int group_can_go_on(struct perf_event *event,
693 struct perf_cpu_context *cpuctx,
694 int can_add_hw)
695{
696 /*
697 * Groups consisting entirely of software events can always go on.
698 */
699 if (is_software_only_group(event))
700 return 1;
701 /*
702 * If an exclusive group is already on, no other hardware
703 * events can go on.
704 */
705 if (cpuctx->exclusive)
706 return 0;
707 /*
708 * If this group is exclusive and there are already
709 * events on the CPU, it can't go on.
710 */
711 if (event->attr.exclusive && cpuctx->active_oncpu)
712 return 0;
713 /*
714 * Otherwise, try to add it if all previous groups were able
715 * to go on.
716 */
717 return can_add_hw;
718}
719
720static void add_event_to_ctx(struct perf_event *event,
721 struct perf_event_context *ctx)
722{
723 list_add_event(event, ctx);
724 event->tstamp_enabled = ctx->time;
725 event->tstamp_running = ctx->time;
726 event->tstamp_stopped = ctx->time;
727}
728
729/*
730 * Cross CPU call to install and enable a performance event
731 *
732 * Must be called with ctx->mutex held
733 */
734static void __perf_install_in_context(void *info)
735{
736 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
737 struct perf_event *event = info;
738 struct perf_event_context *ctx = event->ctx;
739 struct perf_event *leader = event->group_leader;
740 int cpu = smp_processor_id();
741 int err;
742
743 /*
744 * If this is a task context, we need to check whether it is
745 * the current task context of this cpu. If not it has been
746 * scheduled out before the smp call arrived.
747 * Or possibly this is the right context but it isn't
748 * on this cpu because it had no events.
749 */
750 if (ctx->task && cpuctx->task_ctx != ctx) {
751 if (cpuctx->task_ctx || ctx->task != current)
752 return;
753 cpuctx->task_ctx = ctx;
754 }
755
756 spin_lock(&ctx->lock);
757 ctx->is_active = 1;
758 update_context_time(ctx);
759
760 /*
761 * Protect the list operation against NMI by disabling the
762 * events on a global level. NOP for non NMI based events.
763 */
764 perf_disable();
765
766 add_event_to_ctx(event, ctx);
767
768 /*
769 * Don't put the event on if it is disabled or if
770 * it is in a group and the group isn't on.
771 */
772 if (event->state != PERF_EVENT_STATE_INACTIVE ||
773 (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE))
774 goto unlock;
775
776 /*
777 * An exclusive event can't go on if there are already active
778 * hardware events, and no hardware event can go on if there
779 * is already an exclusive event on.
780 */
781 if (!group_can_go_on(event, cpuctx, 1))
782 err = -EEXIST;
783 else
784 err = event_sched_in(event, cpuctx, ctx, cpu);
785
786 if (err) {
787 /*
788 * This event couldn't go on. If it is in a group
789 * then we have to pull the whole group off.
790 * If the event group is pinned then put it in error state.
791 */
792 if (leader != event)
793 group_sched_out(leader, cpuctx, ctx);
794 if (leader->attr.pinned) {
795 update_group_times(leader);
796 leader->state = PERF_EVENT_STATE_ERROR;
797 }
798 }
799
800 if (!err && !ctx->task && cpuctx->max_pertask)
801 cpuctx->max_pertask--;
802
803 unlock:
804 perf_enable();
805
806 spin_unlock(&ctx->lock);
807}
808
809/*
810 * Attach a performance event to a context
811 *
812 * First we add the event to the list with the hardware enable bit
813 * in event->hw_config cleared.
814 *
815 * If the event is attached to a task which is on a CPU we use a smp
816 * call to enable it in the task context. The task might have been
817 * scheduled away, but we check this in the smp call again.
818 *
819 * Must be called with ctx->mutex held.
820 */
821static void
822perf_install_in_context(struct perf_event_context *ctx,
823 struct perf_event *event,
824 int cpu)
825{
826 struct task_struct *task = ctx->task;
827
828 if (!task) {
829 /*
830 * Per cpu events are installed via an smp call and
831 * the install is always sucessful.
832 */
833 smp_call_function_single(cpu, __perf_install_in_context,
834 event, 1);
835 return;
836 }
837
838retry:
839 task_oncpu_function_call(task, __perf_install_in_context,
840 event);
841
842 spin_lock_irq(&ctx->lock);
843 /*
844 * we need to retry the smp call.
845 */
846 if (ctx->is_active && list_empty(&event->group_entry)) {
847 spin_unlock_irq(&ctx->lock);
848 goto retry;
849 }
850
851 /*
852 * The lock prevents that this context is scheduled in so we
853 * can add the event safely, if it the call above did not
854 * succeed.
855 */
856 if (list_empty(&event->group_entry))
857 add_event_to_ctx(event, ctx);
858 spin_unlock_irq(&ctx->lock);
859}
860
861/*
862 * Put a event into inactive state and update time fields.
863 * Enabling the leader of a group effectively enables all
864 * the group members that aren't explicitly disabled, so we
865 * have to update their ->tstamp_enabled also.
866 * Note: this works for group members as well as group leaders
867 * since the non-leader members' sibling_lists will be empty.
868 */
869static void __perf_event_mark_enabled(struct perf_event *event,
870 struct perf_event_context *ctx)
871{
872 struct perf_event *sub;
873
874 event->state = PERF_EVENT_STATE_INACTIVE;
875 event->tstamp_enabled = ctx->time - event->total_time_enabled;
876 list_for_each_entry(sub, &event->sibling_list, group_entry)
877 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
878 sub->tstamp_enabled =
879 ctx->time - sub->total_time_enabled;
880}
881
882/*
883 * Cross CPU call to enable a performance event
884 */
885static void __perf_event_enable(void *info)
886{
887 struct perf_event *event = info;
888 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
889 struct perf_event_context *ctx = event->ctx;
890 struct perf_event *leader = event->group_leader;
891 int err;
892
893 /*
894 * If this is a per-task event, need to check whether this
895 * event's task is the current task on this cpu.
896 */
897 if (ctx->task && cpuctx->task_ctx != ctx) {
898 if (cpuctx->task_ctx || ctx->task != current)
899 return;
900 cpuctx->task_ctx = ctx;
901 }
902
903 spin_lock(&ctx->lock);
904 ctx->is_active = 1;
905 update_context_time(ctx);
906
907 if (event->state >= PERF_EVENT_STATE_INACTIVE)
908 goto unlock;
909 __perf_event_mark_enabled(event, ctx);
910
911 /*
912 * If the event is in a group and isn't the group leader,
913 * then don't put it on unless the group is on.
914 */
915 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
916 goto unlock;
917
918 if (!group_can_go_on(event, cpuctx, 1)) {
919 err = -EEXIST;
920 } else {
921 perf_disable();
922 if (event == leader)
923 err = group_sched_in(event, cpuctx, ctx,
924 smp_processor_id());
925 else
926 err = event_sched_in(event, cpuctx, ctx,
927 smp_processor_id());
928 perf_enable();
929 }
930
931 if (err) {
932 /*
933 * If this event can't go on and it's part of a
934 * group, then the whole group has to come off.
935 */
936 if (leader != event)
937 group_sched_out(leader, cpuctx, ctx);
938 if (leader->attr.pinned) {
939 update_group_times(leader);
940 leader->state = PERF_EVENT_STATE_ERROR;
941 }
942 }
943
944 unlock:
945 spin_unlock(&ctx->lock);
946}
947
948/*
949 * Enable a event.
950 *
951 * If event->ctx is a cloned context, callers must make sure that
952 * every task struct that event->ctx->task could possibly point to
953 * remains valid. This condition is satisfied when called through
954 * perf_event_for_each_child or perf_event_for_each as described
955 * for perf_event_disable.
956 */
957static void perf_event_enable(struct perf_event *event)
958{
959 struct perf_event_context *ctx = event->ctx;
960 struct task_struct *task = ctx->task;
961
962 if (!task) {
963 /*
964 * Enable the event on the cpu that it's on
965 */
966 smp_call_function_single(event->cpu, __perf_event_enable,
967 event, 1);
968 return;
969 }
970
971 spin_lock_irq(&ctx->lock);
972 if (event->state >= PERF_EVENT_STATE_INACTIVE)
973 goto out;
974
975 /*
976 * If the event is in error state, clear that first.
977 * That way, if we see the event in error state below, we
978 * know that it has gone back into error state, as distinct
979 * from the task having been scheduled away before the
980 * cross-call arrived.
981 */
982 if (event->state == PERF_EVENT_STATE_ERROR)
983 event->state = PERF_EVENT_STATE_OFF;
984
985 retry:
986 spin_unlock_irq(&ctx->lock);
987 task_oncpu_function_call(task, __perf_event_enable, event);
988
989 spin_lock_irq(&ctx->lock);
990
991 /*
992 * If the context is active and the event is still off,
993 * we need to retry the cross-call.
994 */
995 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF)
996 goto retry;
997
998 /*
999 * Since we have the lock this context can't be scheduled
1000 * in, so we can change the state safely.
1001 */
1002 if (event->state == PERF_EVENT_STATE_OFF)
1003 __perf_event_mark_enabled(event, ctx);
1004
1005 out:
1006 spin_unlock_irq(&ctx->lock);
1007}
1008
1009static int perf_event_refresh(struct perf_event *event, int refresh)
1010{
1011 /*
1012 * not supported on inherited events
1013 */
1014 if (event->attr.inherit)
1015 return -EINVAL;
1016
1017 atomic_add(refresh, &event->event_limit);
1018 perf_event_enable(event);
1019
1020 return 0;
1021}
1022
1023void __perf_event_sched_out(struct perf_event_context *ctx,
1024 struct perf_cpu_context *cpuctx)
1025{
1026 struct perf_event *event;
1027
1028 spin_lock(&ctx->lock);
1029 ctx->is_active = 0;
1030 if (likely(!ctx->nr_events))
1031 goto out;
1032 update_context_time(ctx);
1033
1034 perf_disable();
1035 if (ctx->nr_active)
1036 list_for_each_entry(event, &ctx->group_list, group_entry)
1037 group_sched_out(event, cpuctx, ctx);
1038
1039 perf_enable();
1040 out:
1041 spin_unlock(&ctx->lock);
1042}
1043
1044/*
1045 * Test whether two contexts are equivalent, i.e. whether they
1046 * have both been cloned from the same version of the same context
1047 * and they both have the same number of enabled events.
1048 * If the number of enabled events is the same, then the set
1049 * of enabled events should be the same, because these are both
1050 * inherited contexts, therefore we can't access individual events
1051 * in them directly with an fd; we can only enable/disable all
1052 * events via prctl, or enable/disable all events in a family
1053 * via ioctl, which will have the same effect on both contexts.
1054 */
1055static int context_equiv(struct perf_event_context *ctx1,
1056 struct perf_event_context *ctx2)
1057{
1058 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1059 && ctx1->parent_gen == ctx2->parent_gen
1060 && !ctx1->pin_count && !ctx2->pin_count;
1061}
1062
1063static void __perf_event_read(void *event);
1064
1065static void __perf_event_sync_stat(struct perf_event *event,
1066 struct perf_event *next_event)
1067{
1068 u64 value;
1069
1070 if (!event->attr.inherit_stat)
1071 return;
1072
1073 /*
1074 * Update the event value, we cannot use perf_event_read()
1075 * because we're in the middle of a context switch and have IRQs
1076 * disabled, which upsets smp_call_function_single(), however
1077 * we know the event must be on the current CPU, therefore we
1078 * don't need to use it.
1079 */
1080 switch (event->state) {
1081 case PERF_EVENT_STATE_ACTIVE:
1082 __perf_event_read(event);
1083 break;
1084
1085 case PERF_EVENT_STATE_INACTIVE:
1086 update_event_times(event);
1087 break;
1088
1089 default:
1090 break;
1091 }
1092
1093 /*
1094 * In order to keep per-task stats reliable we need to flip the event
1095 * values when we flip the contexts.
1096 */
1097 value = atomic64_read(&next_event->count);
1098 value = atomic64_xchg(&event->count, value);
1099 atomic64_set(&next_event->count, value);
1100
1101 swap(event->total_time_enabled, next_event->total_time_enabled);
1102 swap(event->total_time_running, next_event->total_time_running);
1103
1104 /*
1105 * Since we swizzled the values, update the user visible data too.
1106 */
1107 perf_event_update_userpage(event);
1108 perf_event_update_userpage(next_event);
1109}
1110
1111#define list_next_entry(pos, member) \
1112 list_entry(pos->member.next, typeof(*pos), member)
1113
1114static void perf_event_sync_stat(struct perf_event_context *ctx,
1115 struct perf_event_context *next_ctx)
1116{
1117 struct perf_event *event, *next_event;
1118
1119 if (!ctx->nr_stat)
1120 return;
1121
1122 event = list_first_entry(&ctx->event_list,
1123 struct perf_event, event_entry);
1124
1125 next_event = list_first_entry(&next_ctx->event_list,
1126 struct perf_event, event_entry);
1127
1128 while (&event->event_entry != &ctx->event_list &&
1129 &next_event->event_entry != &next_ctx->event_list) {
1130
1131 __perf_event_sync_stat(event, next_event);
1132
1133 event = list_next_entry(event, event_entry);
1134 next_event = list_next_entry(next_event, event_entry);
1135 }
1136}
1137
1138/*
1139 * Called from scheduler to remove the events of the current task,
1140 * with interrupts disabled.
1141 *
1142 * We stop each event and update the event value in event->count.
1143 *
1144 * This does not protect us against NMI, but disable()
1145 * sets the disabled bit in the control field of event _before_
1146 * accessing the event control register. If a NMI hits, then it will
1147 * not restart the event.
1148 */
1149void perf_event_task_sched_out(struct task_struct *task,
1150 struct task_struct *next, int cpu)
1151{
1152 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1153 struct perf_event_context *ctx = task->perf_event_ctxp;
1154 struct perf_event_context *next_ctx;
1155 struct perf_event_context *parent;
1156 struct pt_regs *regs;
1157 int do_switch = 1;
1158
1159 regs = task_pt_regs(task);
1160 perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, regs, 0);
1161
1162 if (likely(!ctx || !cpuctx->task_ctx))
1163 return;
1164
1165 update_context_time(ctx);
1166
1167 rcu_read_lock();
1168 parent = rcu_dereference(ctx->parent_ctx);
1169 next_ctx = next->perf_event_ctxp;
1170 if (parent && next_ctx &&
1171 rcu_dereference(next_ctx->parent_ctx) == parent) {
1172 /*
1173 * Looks like the two contexts are clones, so we might be
1174 * able to optimize the context switch. We lock both
1175 * contexts and check that they are clones under the
1176 * lock (including re-checking that neither has been
1177 * uncloned in the meantime). It doesn't matter which
1178 * order we take the locks because no other cpu could
1179 * be trying to lock both of these tasks.
1180 */
1181 spin_lock(&ctx->lock);
1182 spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1183 if (context_equiv(ctx, next_ctx)) {
1184 /*
1185 * XXX do we need a memory barrier of sorts
1186 * wrt to rcu_dereference() of perf_event_ctxp
1187 */
1188 task->perf_event_ctxp = next_ctx;
1189 next->perf_event_ctxp = ctx;
1190 ctx->task = next;
1191 next_ctx->task = task;
1192 do_switch = 0;
1193
1194 perf_event_sync_stat(ctx, next_ctx);
1195 }
1196 spin_unlock(&next_ctx->lock);
1197 spin_unlock(&ctx->lock);
1198 }
1199 rcu_read_unlock();
1200
1201 if (do_switch) {
1202 __perf_event_sched_out(ctx, cpuctx);
1203 cpuctx->task_ctx = NULL;
1204 }
1205}
1206
1207/*
1208 * Called with IRQs disabled
1209 */
1210static void __perf_event_task_sched_out(struct perf_event_context *ctx)
1211{
1212 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1213
1214 if (!cpuctx->task_ctx)
1215 return;
1216
1217 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
1218 return;
1219
1220 __perf_event_sched_out(ctx, cpuctx);
1221 cpuctx->task_ctx = NULL;
1222}
1223
1224/*
1225 * Called with IRQs disabled
1226 */
1227static void perf_event_cpu_sched_out(struct perf_cpu_context *cpuctx)
1228{
1229 __perf_event_sched_out(&cpuctx->ctx, cpuctx);
1230}
1231
1232static void
1233__perf_event_sched_in(struct perf_event_context *ctx,
1234 struct perf_cpu_context *cpuctx, int cpu)
1235{
1236 struct perf_event *event;
1237 int can_add_hw = 1;
1238
1239 spin_lock(&ctx->lock);
1240 ctx->is_active = 1;
1241 if (likely(!ctx->nr_events))
1242 goto out;
1243
1244 ctx->timestamp = perf_clock();
1245
1246 perf_disable();
1247
1248 /*
1249 * First go through the list and put on any pinned groups
1250 * in order to give them the best chance of going on.
1251 */
1252 list_for_each_entry(event, &ctx->group_list, group_entry) {
1253 if (event->state <= PERF_EVENT_STATE_OFF ||
1254 !event->attr.pinned)
1255 continue;
1256 if (event->cpu != -1 && event->cpu != cpu)
1257 continue;
1258
1259 if (group_can_go_on(event, cpuctx, 1))
1260 group_sched_in(event, cpuctx, ctx, cpu);
1261
1262 /*
1263 * If this pinned group hasn't been scheduled,
1264 * put it in error state.
1265 */
1266 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1267 update_group_times(event);
1268 event->state = PERF_EVENT_STATE_ERROR;
1269 }
1270 }
1271
1272 list_for_each_entry(event, &ctx->group_list, group_entry) {
1273 /*
1274 * Ignore events in OFF or ERROR state, and
1275 * ignore pinned events since we did them already.
1276 */
1277 if (event->state <= PERF_EVENT_STATE_OFF ||
1278 event->attr.pinned)
1279 continue;
1280
1281 /*
1282 * Listen to the 'cpu' scheduling filter constraint
1283 * of events:
1284 */
1285 if (event->cpu != -1 && event->cpu != cpu)
1286 continue;
1287
1288 if (group_can_go_on(event, cpuctx, can_add_hw))
1289 if (group_sched_in(event, cpuctx, ctx, cpu))
1290 can_add_hw = 0;
1291 }
1292 perf_enable();
1293 out:
1294 spin_unlock(&ctx->lock);
1295}
1296
1297/*
1298 * Called from scheduler to add the events of the current task
1299 * with interrupts disabled.
1300 *
1301 * We restore the event value and then enable it.
1302 *
1303 * This does not protect us against NMI, but enable()
1304 * sets the enabled bit in the control field of event _before_
1305 * accessing the event control register. If a NMI hits, then it will
1306 * keep the event running.
1307 */
1308void perf_event_task_sched_in(struct task_struct *task, int cpu)
1309{
1310 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
1311 struct perf_event_context *ctx = task->perf_event_ctxp;
1312
1313 if (likely(!ctx))
1314 return;
1315 if (cpuctx->task_ctx == ctx)
1316 return;
1317 __perf_event_sched_in(ctx, cpuctx, cpu);
1318 cpuctx->task_ctx = ctx;
1319}
1320
1321static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
1322{
1323 struct perf_event_context *ctx = &cpuctx->ctx;
1324
1325 __perf_event_sched_in(ctx, cpuctx, cpu);
1326}
1327
1328#define MAX_INTERRUPTS (~0ULL)
1329
1330static void perf_log_throttle(struct perf_event *event, int enable);
1331
1332static void perf_adjust_period(struct perf_event *event, u64 events)
1333{
1334 struct hw_perf_event *hwc = &event->hw;
1335 u64 period, sample_period;
1336 s64 delta;
1337
1338 events *= hwc->sample_period;
1339 period = div64_u64(events, event->attr.sample_freq);
1340
1341 delta = (s64)(period - hwc->sample_period);
1342 delta = (delta + 7) / 8; /* low pass filter */
1343
1344 sample_period = hwc->sample_period + delta;
1345
1346 if (!sample_period)
1347 sample_period = 1;
1348
1349 hwc->sample_period = sample_period;
1350}
1351
1352static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
1353{
1354 struct perf_event *event;
1355 struct hw_perf_event *hwc;
1356 u64 interrupts, freq;
1357
1358 spin_lock(&ctx->lock);
1359 list_for_each_entry(event, &ctx->group_list, group_entry) {
1360 if (event->state != PERF_EVENT_STATE_ACTIVE)
1361 continue;
1362
1363 hwc = &event->hw;
1364
1365 interrupts = hwc->interrupts;
1366 hwc->interrupts = 0;
1367
1368 /*
1369 * unthrottle events on the tick
1370 */
1371 if (interrupts == MAX_INTERRUPTS) {
1372 perf_log_throttle(event, 1);
1373 event->pmu->unthrottle(event);
1374 interrupts = 2*sysctl_perf_event_sample_rate/HZ;
1375 }
1376
1377 if (!event->attr.freq || !event->attr.sample_freq)
1378 continue;
1379
1380 /*
1381 * if the specified freq < HZ then we need to skip ticks
1382 */
1383 if (event->attr.sample_freq < HZ) {
1384 freq = event->attr.sample_freq;
1385
1386 hwc->freq_count += freq;
1387 hwc->freq_interrupts += interrupts;
1388
1389 if (hwc->freq_count < HZ)
1390 continue;
1391
1392 interrupts = hwc->freq_interrupts;
1393 hwc->freq_interrupts = 0;
1394 hwc->freq_count -= HZ;
1395 } else
1396 freq = HZ;
1397
1398 perf_adjust_period(event, freq * interrupts);
1399
1400 /*
1401 * In order to avoid being stalled by an (accidental) huge
1402 * sample period, force reset the sample period if we didn't
1403 * get any events in this freq period.
1404 */
1405 if (!interrupts) {
1406 perf_disable();
1407 event->pmu->disable(event);
1408 atomic64_set(&hwc->period_left, 0);
1409 event->pmu->enable(event);
1410 perf_enable();
1411 }
1412 }
1413 spin_unlock(&ctx->lock);
1414}
1415
1416/*
1417 * Round-robin a context's events:
1418 */
1419static void rotate_ctx(struct perf_event_context *ctx)
1420{
1421 struct perf_event *event;
1422
1423 if (!ctx->nr_events)
1424 return;
1425
1426 spin_lock(&ctx->lock);
1427 /*
1428 * Rotate the first entry last (works just fine for group events too):
1429 */
1430 perf_disable();
1431 list_for_each_entry(event, &ctx->group_list, group_entry) {
1432 list_move_tail(&event->group_entry, &ctx->group_list);
1433 break;
1434 }
1435 perf_enable();
1436
1437 spin_unlock(&ctx->lock);
1438}
1439
1440void perf_event_task_tick(struct task_struct *curr, int cpu)
1441{
1442 struct perf_cpu_context *cpuctx;
1443 struct perf_event_context *ctx;
1444
1445 if (!atomic_read(&nr_events))
1446 return;
1447
1448 cpuctx = &per_cpu(perf_cpu_context, cpu);
1449 ctx = curr->perf_event_ctxp;
1450
1451 perf_ctx_adjust_freq(&cpuctx->ctx);
1452 if (ctx)
1453 perf_ctx_adjust_freq(ctx);
1454
1455 perf_event_cpu_sched_out(cpuctx);
1456 if (ctx)
1457 __perf_event_task_sched_out(ctx);
1458
1459 rotate_ctx(&cpuctx->ctx);
1460 if (ctx)
1461 rotate_ctx(ctx);
1462
1463 perf_event_cpu_sched_in(cpuctx, cpu);
1464 if (ctx)
1465 perf_event_task_sched_in(curr, cpu);
1466}
1467
1468/*
1469 * Enable all of a task's events that have been marked enable-on-exec.
1470 * This expects task == current.
1471 */
1472static void perf_event_enable_on_exec(struct task_struct *task)
1473{
1474 struct perf_event_context *ctx;
1475 struct perf_event *event;
1476 unsigned long flags;
1477 int enabled = 0;
1478
1479 local_irq_save(flags);
1480 ctx = task->perf_event_ctxp;
1481 if (!ctx || !ctx->nr_events)
1482 goto out;
1483
1484 __perf_event_task_sched_out(ctx);
1485
1486 spin_lock(&ctx->lock);
1487
1488 list_for_each_entry(event, &ctx->group_list, group_entry) {
1489 if (!event->attr.enable_on_exec)
1490 continue;
1491 event->attr.enable_on_exec = 0;
1492 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1493 continue;
1494 __perf_event_mark_enabled(event, ctx);
1495 enabled = 1;
1496 }
1497
1498 /*
1499 * Unclone this context if we enabled any event.
1500 */
1501 if (enabled)
1502 unclone_ctx(ctx);
1503
1504 spin_unlock(&ctx->lock);
1505
1506 perf_event_task_sched_in(task, smp_processor_id());
1507 out:
1508 local_irq_restore(flags);
1509}
1510
1511/*
1512 * Cross CPU call to read the hardware event
1513 */
1514static void __perf_event_read(void *info)
1515{
1516 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
1517 struct perf_event *event = info;
1518 struct perf_event_context *ctx = event->ctx;
1519 unsigned long flags;
1520
1521 /*
1522 * If this is a task context, we need to check whether it is
1523 * the current task context of this cpu. If not it has been
1524 * scheduled out before the smp call arrived. In that case
1525 * event->count would have been updated to a recent sample
1526 * when the event was scheduled out.
1527 */
1528 if (ctx->task && cpuctx->task_ctx != ctx)
1529 return;
1530
1531 local_irq_save(flags);
1532 if (ctx->is_active)
1533 update_context_time(ctx);
1534 event->pmu->read(event);
1535 update_event_times(event);
1536 local_irq_restore(flags);
1537}
1538
1539static u64 perf_event_read(struct perf_event *event)
1540{
1541 /*
1542 * If event is enabled and currently active on a CPU, update the
1543 * value in the event structure:
1544 */
1545 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1546 smp_call_function_single(event->oncpu,
1547 __perf_event_read, event, 1);
1548 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
1549 update_event_times(event);
1550 }
1551
1552 return atomic64_read(&event->count);
1553}
1554
1555/*
1556 * Initialize the perf_event context in a task_struct:
1557 */
1558static void
1559__perf_event_init_context(struct perf_event_context *ctx,
1560 struct task_struct *task)
1561{
1562 memset(ctx, 0, sizeof(*ctx));
1563 spin_lock_init(&ctx->lock);
1564 mutex_init(&ctx->mutex);
1565 INIT_LIST_HEAD(&ctx->group_list);
1566 INIT_LIST_HEAD(&ctx->event_list);
1567 atomic_set(&ctx->refcount, 1);
1568 ctx->task = task;
1569}
1570
1571static struct perf_event_context *find_get_context(pid_t pid, int cpu)
1572{
1573 struct perf_event_context *ctx;
1574 struct perf_cpu_context *cpuctx;
1575 struct task_struct *task;
1576 unsigned long flags;
1577 int err;
1578
1579 /*
1580 * If cpu is not a wildcard then this is a percpu event:
1581 */
1582 if (cpu != -1) {
1583 /* Must be root to operate on a CPU event: */
1584 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
1585 return ERR_PTR(-EACCES);
1586
1587 if (cpu < 0 || cpu > num_possible_cpus())
1588 return ERR_PTR(-EINVAL);
1589
1590 /*
1591 * We could be clever and allow to attach a event to an
1592 * offline CPU and activate it when the CPU comes up, but
1593 * that's for later.
1594 */
1595 if (!cpu_isset(cpu, cpu_online_map))
1596 return ERR_PTR(-ENODEV);
1597
1598 cpuctx = &per_cpu(perf_cpu_context, cpu);
1599 ctx = &cpuctx->ctx;
1600 get_ctx(ctx);
1601
1602 return ctx;
1603 }
1604
1605 rcu_read_lock();
1606 if (!pid)
1607 task = current;
1608 else
1609 task = find_task_by_vpid(pid);
1610 if (task)
1611 get_task_struct(task);
1612 rcu_read_unlock();
1613
1614 if (!task)
1615 return ERR_PTR(-ESRCH);
1616
1617 /*
1618 * Can't attach events to a dying task.
1619 */
1620 err = -ESRCH;
1621 if (task->flags & PF_EXITING)
1622 goto errout;
1623
1624 /* Reuse ptrace permission checks for now. */
1625 err = -EACCES;
1626 if (!ptrace_may_access(task, PTRACE_MODE_READ))
1627 goto errout;
1628
1629 retry:
1630 ctx = perf_lock_task_context(task, &flags);
1631 if (ctx) {
1632 unclone_ctx(ctx);
1633 spin_unlock_irqrestore(&ctx->lock, flags);
1634 }
1635
1636 if (!ctx) {
1637 ctx = kmalloc(sizeof(struct perf_event_context), GFP_KERNEL);
1638 err = -ENOMEM;
1639 if (!ctx)
1640 goto errout;
1641 __perf_event_init_context(ctx, task);
1642 get_ctx(ctx);
1643 if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
1644 /*
1645 * We raced with some other task; use
1646 * the context they set.
1647 */
1648 kfree(ctx);
1649 goto retry;
1650 }
1651 get_task_struct(task);
1652 }
1653
1654 put_task_struct(task);
1655 return ctx;
1656
1657 errout:
1658 put_task_struct(task);
1659 return ERR_PTR(err);
1660}
1661
1662static void perf_event_free_filter(struct perf_event *event);
1663
1664static void free_event_rcu(struct rcu_head *head)
1665{
1666 struct perf_event *event;
1667
1668 event = container_of(head, struct perf_event, rcu_head);
1669 if (event->ns)
1670 put_pid_ns(event->ns);
1671 perf_event_free_filter(event);
1672 kfree(event);
1673}
1674
1675static void perf_pending_sync(struct perf_event *event);
1676
1677static void free_event(struct perf_event *event)
1678{
1679 perf_pending_sync(event);
1680
1681 if (!event->parent) {
1682 atomic_dec(&nr_events);
1683 if (event->attr.mmap)
1684 atomic_dec(&nr_mmap_events);
1685 if (event->attr.comm)
1686 atomic_dec(&nr_comm_events);
1687 if (event->attr.task)
1688 atomic_dec(&nr_task_events);
1689 }
1690
1691 if (event->output) {
1692 fput(event->output->filp);
1693 event->output = NULL;
1694 }
1695
1696 if (event->destroy)
1697 event->destroy(event);
1698
1699 put_ctx(event->ctx);
1700 call_rcu(&event->rcu_head, free_event_rcu);
1701}
1702
1703/*
1704 * Called when the last reference to the file is gone.
1705 */
1706static int perf_release(struct inode *inode, struct file *file)
1707{
1708 struct perf_event *event = file->private_data;
1709 struct perf_event_context *ctx = event->ctx;
1710
1711 file->private_data = NULL;
1712
1713 WARN_ON_ONCE(ctx->parent_ctx);
1714 mutex_lock(&ctx->mutex);
1715 perf_event_remove_from_context(event);
1716 mutex_unlock(&ctx->mutex);
1717
1718 mutex_lock(&event->owner->perf_event_mutex);
1719 list_del_init(&event->owner_entry);
1720 mutex_unlock(&event->owner->perf_event_mutex);
1721 put_task_struct(event->owner);
1722
1723 free_event(event);
1724
1725 return 0;
1726}
1727
1728static int perf_event_read_size(struct perf_event *event)
1729{
1730 int entry = sizeof(u64); /* value */
1731 int size = 0;
1732 int nr = 1;
1733
1734 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1735 size += sizeof(u64);
1736
1737 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1738 size += sizeof(u64);
1739
1740 if (event->attr.read_format & PERF_FORMAT_ID)
1741 entry += sizeof(u64);
1742
1743 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1744 nr += event->group_leader->nr_siblings;
1745 size += sizeof(u64);
1746 }
1747
1748 size += entry * nr;
1749
1750 return size;
1751}
1752
1753static u64 perf_event_read_value(struct perf_event *event)
1754{
1755 struct perf_event *child;
1756 u64 total = 0;
1757
1758 total += perf_event_read(event);
1759 list_for_each_entry(child, &event->child_list, child_list)
1760 total += perf_event_read(child);
1761
1762 return total;
1763}
1764
1765static int perf_event_read_entry(struct perf_event *event,
1766 u64 read_format, char __user *buf)
1767{
1768 int n = 0, count = 0;
1769 u64 values[2];
1770
1771 values[n++] = perf_event_read_value(event);
1772 if (read_format & PERF_FORMAT_ID)
1773 values[n++] = primary_event_id(event);
1774
1775 count = n * sizeof(u64);
1776
1777 if (copy_to_user(buf, values, count))
1778 return -EFAULT;
1779
1780 return count;
1781}
1782
1783static int perf_event_read_group(struct perf_event *event,
1784 u64 read_format, char __user *buf)
1785{
1786 struct perf_event *leader = event->group_leader, *sub;
1787 int n = 0, size = 0, err = -EFAULT;
1788 u64 values[3];
1789
1790 values[n++] = 1 + leader->nr_siblings;
1791 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
1792 values[n++] = leader->total_time_enabled +
1793 atomic64_read(&leader->child_total_time_enabled);
1794 }
1795 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
1796 values[n++] = leader->total_time_running +
1797 atomic64_read(&leader->child_total_time_running);
1798 }
1799
1800 size = n * sizeof(u64);
1801
1802 if (copy_to_user(buf, values, size))
1803 return -EFAULT;
1804
1805 err = perf_event_read_entry(leader, read_format, buf + size);
1806 if (err < 0)
1807 return err;
1808
1809 size += err;
1810
1811 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
1812 err = perf_event_read_entry(sub, read_format,
1813 buf + size);
1814 if (err < 0)
1815 return err;
1816
1817 size += err;
1818 }
1819
1820 return size;
1821}
1822
1823static int perf_event_read_one(struct perf_event *event,
1824 u64 read_format, char __user *buf)
1825{
1826 u64 values[4];
1827 int n = 0;
1828
1829 values[n++] = perf_event_read_value(event);
1830 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
1831 values[n++] = event->total_time_enabled +
1832 atomic64_read(&event->child_total_time_enabled);
1833 }
1834 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
1835 values[n++] = event->total_time_running +
1836 atomic64_read(&event->child_total_time_running);
1837 }
1838 if (read_format & PERF_FORMAT_ID)
1839 values[n++] = primary_event_id(event);
1840
1841 if (copy_to_user(buf, values, n * sizeof(u64)))
1842 return -EFAULT;
1843
1844 return n * sizeof(u64);
1845}
1846
1847/*
1848 * Read the performance event - simple non blocking version for now
1849 */
1850static ssize_t
1851perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
1852{
1853 u64 read_format = event->attr.read_format;
1854 int ret;
1855
1856 /*
1857 * Return end-of-file for a read on a event that is in
1858 * error state (i.e. because it was pinned but it couldn't be
1859 * scheduled on to the CPU at some point).
1860 */
1861 if (event->state == PERF_EVENT_STATE_ERROR)
1862 return 0;
1863
1864 if (count < perf_event_read_size(event))
1865 return -ENOSPC;
1866
1867 WARN_ON_ONCE(event->ctx->parent_ctx);
1868 mutex_lock(&event->child_mutex);
1869 if (read_format & PERF_FORMAT_GROUP)
1870 ret = perf_event_read_group(event, read_format, buf);
1871 else
1872 ret = perf_event_read_one(event, read_format, buf);
1873 mutex_unlock(&event->child_mutex);
1874
1875 return ret;
1876}
1877
1878static ssize_t
1879perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
1880{
1881 struct perf_event *event = file->private_data;
1882
1883 return perf_read_hw(event, buf, count);
1884}
1885
1886static unsigned int perf_poll(struct file *file, poll_table *wait)
1887{
1888 struct perf_event *event = file->private_data;
1889 struct perf_mmap_data *data;
1890 unsigned int events = POLL_HUP;
1891
1892 rcu_read_lock();
1893 data = rcu_dereference(event->data);
1894 if (data)
1895 events = atomic_xchg(&data->poll, 0);
1896 rcu_read_unlock();
1897
1898 poll_wait(file, &event->waitq, wait);
1899
1900 return events;
1901}
1902
1903static void perf_event_reset(struct perf_event *event)
1904{
1905 (void)perf_event_read(event);
1906 atomic64_set(&event->count, 0);
1907 perf_event_update_userpage(event);
1908}
1909
1910/*
1911 * Holding the top-level event's child_mutex means that any
1912 * descendant process that has inherited this event will block
1913 * in sync_child_event if it goes to exit, thus satisfying the
1914 * task existence requirements of perf_event_enable/disable.
1915 */
1916static void perf_event_for_each_child(struct perf_event *event,
1917 void (*func)(struct perf_event *))
1918{
1919 struct perf_event *child;
1920
1921 WARN_ON_ONCE(event->ctx->parent_ctx);
1922 mutex_lock(&event->child_mutex);
1923 func(event);
1924 list_for_each_entry(child, &event->child_list, child_list)
1925 func(child);
1926 mutex_unlock(&event->child_mutex);
1927}
1928
1929static void perf_event_for_each(struct perf_event *event,
1930 void (*func)(struct perf_event *))
1931{
1932 struct perf_event_context *ctx = event->ctx;
1933 struct perf_event *sibling;
1934
1935 WARN_ON_ONCE(ctx->parent_ctx);
1936 mutex_lock(&ctx->mutex);
1937 event = event->group_leader;
1938
1939 perf_event_for_each_child(event, func);
1940 func(event);
1941 list_for_each_entry(sibling, &event->sibling_list, group_entry)
1942 perf_event_for_each_child(event, func);
1943 mutex_unlock(&ctx->mutex);
1944}
1945
1946static int perf_event_period(struct perf_event *event, u64 __user *arg)
1947{
1948 struct perf_event_context *ctx = event->ctx;
1949 unsigned long size;
1950 int ret = 0;
1951 u64 value;
1952
1953 if (!event->attr.sample_period)
1954 return -EINVAL;
1955
1956 size = copy_from_user(&value, arg, sizeof(value));
1957 if (size != sizeof(value))
1958 return -EFAULT;
1959
1960 if (!value)
1961 return -EINVAL;
1962
1963 spin_lock_irq(&ctx->lock);
1964 if (event->attr.freq) {
1965 if (value > sysctl_perf_event_sample_rate) {
1966 ret = -EINVAL;
1967 goto unlock;
1968 }
1969
1970 event->attr.sample_freq = value;
1971 } else {
1972 event->attr.sample_period = value;
1973 event->hw.sample_period = value;
1974 }
1975unlock:
1976 spin_unlock_irq(&ctx->lock);
1977
1978 return ret;
1979}
1980
1981static int perf_event_set_output(struct perf_event *event, int output_fd);
1982static int perf_event_set_filter(struct perf_event *event, void __user *arg);
1983
1984static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1985{
1986 struct perf_event *event = file->private_data;
1987 void (*func)(struct perf_event *);
1988 u32 flags = arg;
1989
1990 switch (cmd) {
1991 case PERF_EVENT_IOC_ENABLE:
1992 func = perf_event_enable;
1993 break;
1994 case PERF_EVENT_IOC_DISABLE:
1995 func = perf_event_disable;
1996 break;
1997 case PERF_EVENT_IOC_RESET:
1998 func = perf_event_reset;
1999 break;
2000
2001 case PERF_EVENT_IOC_REFRESH:
2002 return perf_event_refresh(event, arg);
2003
2004 case PERF_EVENT_IOC_PERIOD:
2005 return perf_event_period(event, (u64 __user *)arg);
2006
2007 case PERF_EVENT_IOC_SET_OUTPUT:
2008 return perf_event_set_output(event, arg);
2009
2010 case PERF_EVENT_IOC_SET_FILTER:
2011 return perf_event_set_filter(event, (void __user *)arg);
2012
2013 default:
2014 return -ENOTTY;
2015 }
2016
2017 if (flags & PERF_IOC_FLAG_GROUP)
2018 perf_event_for_each(event, func);
2019 else
2020 perf_event_for_each_child(event, func);
2021
2022 return 0;
2023}
2024
2025int perf_event_task_enable(void)
2026{
2027 struct perf_event *event;
2028
2029 mutex_lock(&current->perf_event_mutex);
2030 list_for_each_entry(event, &current->perf_event_list, owner_entry)
2031 perf_event_for_each_child(event, perf_event_enable);
2032 mutex_unlock(&current->perf_event_mutex);
2033
2034 return 0;
2035}
2036
2037int perf_event_task_disable(void)
2038{
2039 struct perf_event *event;
2040
2041 mutex_lock(&current->perf_event_mutex);
2042 list_for_each_entry(event, &current->perf_event_list, owner_entry)
2043 perf_event_for_each_child(event, perf_event_disable);
2044 mutex_unlock(&current->perf_event_mutex);
2045
2046 return 0;
2047}
2048
2049#ifndef PERF_EVENT_INDEX_OFFSET
2050# define PERF_EVENT_INDEX_OFFSET 0
2051#endif
2052
2053static int perf_event_index(struct perf_event *event)
2054{
2055 if (event->state != PERF_EVENT_STATE_ACTIVE)
2056 return 0;
2057
2058 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
2059}
2060
2061/*
2062 * Callers need to ensure there can be no nesting of this function, otherwise
2063 * the seqlock logic goes bad. We can not serialize this because the arch
2064 * code calls this from NMI context.
2065 */
2066void perf_event_update_userpage(struct perf_event *event)
2067{
2068 struct perf_event_mmap_page *userpg;
2069 struct perf_mmap_data *data;
2070
2071 rcu_read_lock();
2072 data = rcu_dereference(event->data);
2073 if (!data)
2074 goto unlock;
2075
2076 userpg = data->user_page;
2077
2078 /*
2079 * Disable preemption so as to not let the corresponding user-space
2080 * spin too long if we get preempted.
2081 */
2082 preempt_disable();
2083 ++userpg->lock;
2084 barrier();
2085 userpg->index = perf_event_index(event);
2086 userpg->offset = atomic64_read(&event->count);
2087 if (event->state == PERF_EVENT_STATE_ACTIVE)
2088 userpg->offset -= atomic64_read(&event->hw.prev_count);
2089
2090 userpg->time_enabled = event->total_time_enabled +
2091 atomic64_read(&event->child_total_time_enabled);
2092
2093 userpg->time_running = event->total_time_running +
2094 atomic64_read(&event->child_total_time_running);
2095
2096 barrier();
2097 ++userpg->lock;
2098 preempt_enable();
2099unlock:
2100 rcu_read_unlock();
2101}
2102
2103static unsigned long perf_data_size(struct perf_mmap_data *data)
2104{
2105 return data->nr_pages << (PAGE_SHIFT + data->data_order);
2106}
2107
2108#ifndef CONFIG_PERF_USE_VMALLOC
2109
2110/*
2111 * Back perf_mmap() with regular GFP_KERNEL-0 pages.
2112 */
2113
2114static struct page *
2115perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2116{
2117 if (pgoff > data->nr_pages)
2118 return NULL;
2119
2120 if (pgoff == 0)
2121 return virt_to_page(data->user_page);
2122
2123 return virt_to_page(data->data_pages[pgoff - 1]);
2124}
2125
2126static struct perf_mmap_data *
2127perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2128{
2129 struct perf_mmap_data *data;
2130 unsigned long size;
2131 int i;
2132
2133 WARN_ON(atomic_read(&event->mmap_count));
2134
2135 size = sizeof(struct perf_mmap_data);
2136 size += nr_pages * sizeof(void *);
2137
2138 data = kzalloc(size, GFP_KERNEL);
2139 if (!data)
2140 goto fail;
2141
2142 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
2143 if (!data->user_page)
2144 goto fail_user_page;
2145
2146 for (i = 0; i < nr_pages; i++) {
2147 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
2148 if (!data->data_pages[i])
2149 goto fail_data_pages;
2150 }
2151
2152 data->data_order = 0;
2153 data->nr_pages = nr_pages;
2154
2155 return data;
2156
2157fail_data_pages:
2158 for (i--; i >= 0; i--)
2159 free_page((unsigned long)data->data_pages[i]);
2160
2161 free_page((unsigned long)data->user_page);
2162
2163fail_user_page:
2164 kfree(data);
2165
2166fail:
2167 return NULL;
2168}
2169
2170static void perf_mmap_free_page(unsigned long addr)
2171{
2172 struct page *page = virt_to_page((void *)addr);
2173
2174 page->mapping = NULL;
2175 __free_page(page);
2176}
2177
2178static void perf_mmap_data_free(struct perf_mmap_data *data)
2179{
2180 int i;
2181
2182 perf_mmap_free_page((unsigned long)data->user_page);
2183 for (i = 0; i < data->nr_pages; i++)
2184 perf_mmap_free_page((unsigned long)data->data_pages[i]);
2185}
2186
2187#else
2188
2189/*
2190 * Back perf_mmap() with vmalloc memory.
2191 *
2192 * Required for architectures that have d-cache aliasing issues.
2193 */
2194
2195static struct page *
2196perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff)
2197{
2198 if (pgoff > (1UL << data->data_order))
2199 return NULL;
2200
2201 return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE);
2202}
2203
2204static void perf_mmap_unmark_page(void *addr)
2205{
2206 struct page *page = vmalloc_to_page(addr);
2207
2208 page->mapping = NULL;
2209}
2210
2211static void perf_mmap_data_free_work(struct work_struct *work)
2212{
2213 struct perf_mmap_data *data;
2214 void *base;
2215 int i, nr;
2216
2217 data = container_of(work, struct perf_mmap_data, work);
2218 nr = 1 << data->data_order;
2219
2220 base = data->user_page;
2221 for (i = 0; i < nr + 1; i++)
2222 perf_mmap_unmark_page(base + (i * PAGE_SIZE));
2223
2224 vfree(base);
2225}
2226
2227static void perf_mmap_data_free(struct perf_mmap_data *data)
2228{
2229 schedule_work(&data->work);
2230}
2231
2232static struct perf_mmap_data *
2233perf_mmap_data_alloc(struct perf_event *event, int nr_pages)
2234{
2235 struct perf_mmap_data *data;
2236 unsigned long size;
2237 void *all_buf;
2238
2239 WARN_ON(atomic_read(&event->mmap_count));
2240
2241 size = sizeof(struct perf_mmap_data);
2242 size += sizeof(void *);
2243
2244 data = kzalloc(size, GFP_KERNEL);
2245 if (!data)
2246 goto fail;
2247
2248 INIT_WORK(&data->work, perf_mmap_data_free_work);
2249
2250 all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
2251 if (!all_buf)
2252 goto fail_all_buf;
2253
2254 data->user_page = all_buf;
2255 data->data_pages[0] = all_buf + PAGE_SIZE;
2256 data->data_order = ilog2(nr_pages);
2257 data->nr_pages = 1;
2258
2259 return data;
2260
2261fail_all_buf:
2262 kfree(data);
2263
2264fail:
2265 return NULL;
2266}
2267
2268#endif
2269
2270static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2271{
2272 struct perf_event *event = vma->vm_file->private_data;
2273 struct perf_mmap_data *data;
2274 int ret = VM_FAULT_SIGBUS;
2275
2276 if (vmf->flags & FAULT_FLAG_MKWRITE) {
2277 if (vmf->pgoff == 0)
2278 ret = 0;
2279 return ret;
2280 }
2281
2282 rcu_read_lock();
2283 data = rcu_dereference(event->data);
2284 if (!data)
2285 goto unlock;
2286
2287 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
2288 goto unlock;
2289
2290 vmf->page = perf_mmap_to_page(data, vmf->pgoff);
2291 if (!vmf->page)
2292 goto unlock;
2293
2294 get_page(vmf->page);
2295 vmf->page->mapping = vma->vm_file->f_mapping;
2296 vmf->page->index = vmf->pgoff;
2297
2298 ret = 0;
2299unlock:
2300 rcu_read_unlock();
2301
2302 return ret;
2303}
2304
2305static void
2306perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data)
2307{
2308 long max_size = perf_data_size(data);
2309
2310 atomic_set(&data->lock, -1);
2311
2312 if (event->attr.watermark) {
2313 data->watermark = min_t(long, max_size,
2314 event->attr.wakeup_watermark);
2315 }
2316
2317 if (!data->watermark)
2318 data->watermark = max_t(long, PAGE_SIZE, max_size / 2);
2319
2320
2321 rcu_assign_pointer(event->data, data);
2322}
2323
2324static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head)
2325{
2326 struct perf_mmap_data *data;
2327
2328 data = container_of(rcu_head, struct perf_mmap_data, rcu_head);
2329 perf_mmap_data_free(data);
2330 kfree(data);
2331}
2332
2333static void perf_mmap_data_release(struct perf_event *event)
2334{
2335 struct perf_mmap_data *data = event->data;
2336
2337 WARN_ON(atomic_read(&event->mmap_count));
2338
2339 rcu_assign_pointer(event->data, NULL);
2340 call_rcu(&data->rcu_head, perf_mmap_data_free_rcu);
2341}
2342
2343static void perf_mmap_open(struct vm_area_struct *vma)
2344{
2345 struct perf_event *event = vma->vm_file->private_data;
2346
2347 atomic_inc(&event->mmap_count);
2348}
2349
2350static void perf_mmap_close(struct vm_area_struct *vma)
2351{
2352 struct perf_event *event = vma->vm_file->private_data;
2353
2354 WARN_ON_ONCE(event->ctx->parent_ctx);
2355 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
2356 unsigned long size = perf_data_size(event->data);
2357 struct user_struct *user = current_user();
2358
2359 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
2360 vma->vm_mm->locked_vm -= event->data->nr_locked;
2361 perf_mmap_data_release(event);
2362 mutex_unlock(&event->mmap_mutex);
2363 }
2364}
2365
2366static const struct vm_operations_struct perf_mmap_vmops = {
2367 .open = perf_mmap_open,
2368 .close = perf_mmap_close,
2369 .fault = perf_mmap_fault,
2370 .page_mkwrite = perf_mmap_fault,
2371};
2372
2373static int perf_mmap(struct file *file, struct vm_area_struct *vma)
2374{
2375 struct perf_event *event = file->private_data;
2376 unsigned long user_locked, user_lock_limit;
2377 struct user_struct *user = current_user();
2378 unsigned long locked, lock_limit;
2379 struct perf_mmap_data *data;
2380 unsigned long vma_size;
2381 unsigned long nr_pages;
2382 long user_extra, extra;
2383 int ret = 0;
2384
2385 if (!(vma->vm_flags & VM_SHARED))
2386 return -EINVAL;
2387
2388 vma_size = vma->vm_end - vma->vm_start;
2389 nr_pages = (vma_size / PAGE_SIZE) - 1;
2390
2391 /*
2392 * If we have data pages ensure they're a power-of-two number, so we
2393 * can do bitmasks instead of modulo.
2394 */
2395 if (nr_pages != 0 && !is_power_of_2(nr_pages))
2396 return -EINVAL;
2397
2398 if (vma_size != PAGE_SIZE * (1 + nr_pages))
2399 return -EINVAL;
2400
2401 if (vma->vm_pgoff != 0)
2402 return -EINVAL;
2403
2404 WARN_ON_ONCE(event->ctx->parent_ctx);
2405 mutex_lock(&event->mmap_mutex);
2406 if (event->output) {
2407 ret = -EINVAL;
2408 goto unlock;
2409 }
2410
2411 if (atomic_inc_not_zero(&event->mmap_count)) {
2412 if (nr_pages != event->data->nr_pages)
2413 ret = -EINVAL;
2414 goto unlock;
2415 }
2416
2417 user_extra = nr_pages + 1;
2418 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
2419
2420 /*
2421 * Increase the limit linearly with more CPUs:
2422 */
2423 user_lock_limit *= num_online_cpus();
2424
2425 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
2426
2427 extra = 0;
2428 if (user_locked > user_lock_limit)
2429 extra = user_locked - user_lock_limit;
2430
2431 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
2432 lock_limit >>= PAGE_SHIFT;
2433 locked = vma->vm_mm->locked_vm + extra;
2434
2435 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
2436 !capable(CAP_IPC_LOCK)) {
2437 ret = -EPERM;
2438 goto unlock;
2439 }
2440
2441 WARN_ON(event->data);
2442
2443 data = perf_mmap_data_alloc(event, nr_pages);
2444 ret = -ENOMEM;
2445 if (!data)
2446 goto unlock;
2447
2448 ret = 0;
2449 perf_mmap_data_init(event, data);
2450
2451 atomic_set(&event->mmap_count, 1);
2452 atomic_long_add(user_extra, &user->locked_vm);
2453 vma->vm_mm->locked_vm += extra;
2454 event->data->nr_locked = extra;
2455 if (vma->vm_flags & VM_WRITE)
2456 event->data->writable = 1;
2457
2458unlock:
2459 mutex_unlock(&event->mmap_mutex);
2460
2461 vma->vm_flags |= VM_RESERVED;
2462 vma->vm_ops = &perf_mmap_vmops;
2463
2464 return ret;
2465}
2466
2467static int perf_fasync(int fd, struct file *filp, int on)
2468{
2469 struct inode *inode = filp->f_path.dentry->d_inode;
2470 struct perf_event *event = filp->private_data;
2471 int retval;
2472
2473 mutex_lock(&inode->i_mutex);
2474 retval = fasync_helper(fd, filp, on, &event->fasync);
2475 mutex_unlock(&inode->i_mutex);
2476
2477 if (retval < 0)
2478 return retval;
2479
2480 return 0;
2481}
2482
2483static const struct file_operations perf_fops = {
2484 .release = perf_release,
2485 .read = perf_read,
2486 .poll = perf_poll,
2487 .unlocked_ioctl = perf_ioctl,
2488 .compat_ioctl = perf_ioctl,
2489 .mmap = perf_mmap,
2490 .fasync = perf_fasync,
2491};
2492
2493/*
2494 * Perf event wakeup
2495 *
2496 * If there's data, ensure we set the poll() state and publish everything
2497 * to user-space before waking everybody up.
2498 */
2499
2500void perf_event_wakeup(struct perf_event *event)
2501{
2502 wake_up_all(&event->waitq);
2503
2504 if (event->pending_kill) {
2505 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
2506 event->pending_kill = 0;
2507 }
2508}
2509
2510/*
2511 * Pending wakeups
2512 *
2513 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
2514 *
2515 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
2516 * single linked list and use cmpxchg() to add entries lockless.
2517 */
2518
2519static void perf_pending_event(struct perf_pending_entry *entry)
2520{
2521 struct perf_event *event = container_of(entry,
2522 struct perf_event, pending);
2523
2524 if (event->pending_disable) {
2525 event->pending_disable = 0;
2526 __perf_event_disable(event);
2527 }
2528
2529 if (event->pending_wakeup) {
2530 event->pending_wakeup = 0;
2531 perf_event_wakeup(event);
2532 }
2533}
2534
2535#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
2536
2537static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
2538 PENDING_TAIL,
2539};
2540
2541static void perf_pending_queue(struct perf_pending_entry *entry,
2542 void (*func)(struct perf_pending_entry *))
2543{
2544 struct perf_pending_entry **head;
2545
2546 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
2547 return;
2548
2549 entry->func = func;
2550
2551 head = &get_cpu_var(perf_pending_head);
2552
2553 do {
2554 entry->next = *head;
2555 } while (cmpxchg(head, entry->next, entry) != entry->next);
2556
2557 set_perf_event_pending();
2558
2559 put_cpu_var(perf_pending_head);
2560}
2561
2562static int __perf_pending_run(void)
2563{
2564 struct perf_pending_entry *list;
2565 int nr = 0;
2566
2567 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
2568 while (list != PENDING_TAIL) {
2569 void (*func)(struct perf_pending_entry *);
2570 struct perf_pending_entry *entry = list;
2571
2572 list = list->next;
2573
2574 func = entry->func;
2575 entry->next = NULL;
2576 /*
2577 * Ensure we observe the unqueue before we issue the wakeup,
2578 * so that we won't be waiting forever.
2579 * -- see perf_not_pending().
2580 */
2581 smp_wmb();
2582
2583 func(entry);
2584 nr++;
2585 }
2586
2587 return nr;
2588}
2589
2590static inline int perf_not_pending(struct perf_event *event)
2591{
2592 /*
2593 * If we flush on whatever cpu we run, there is a chance we don't
2594 * need to wait.
2595 */
2596 get_cpu();
2597 __perf_pending_run();
2598 put_cpu();
2599
2600 /*
2601 * Ensure we see the proper queue state before going to sleep
2602 * so that we do not miss the wakeup. -- see perf_pending_handle()
2603 */
2604 smp_rmb();
2605 return event->pending.next == NULL;
2606}
2607
2608static void perf_pending_sync(struct perf_event *event)
2609{
2610 wait_event(event->waitq, perf_not_pending(event));
2611}
2612
2613void perf_event_do_pending(void)
2614{
2615 __perf_pending_run();
2616}
2617
2618/*
2619 * Callchain support -- arch specific
2620 */
2621
2622__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2623{
2624 return NULL;
2625}
2626
2627/*
2628 * Output
2629 */
2630static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail,
2631 unsigned long offset, unsigned long head)
2632{
2633 unsigned long mask;
2634
2635 if (!data->writable)
2636 return true;
2637
2638 mask = perf_data_size(data) - 1;
2639
2640 offset = (offset - tail) & mask;
2641 head = (head - tail) & mask;
2642
2643 if ((int)(head - offset) < 0)
2644 return false;
2645
2646 return true;
2647}
2648
2649static void perf_output_wakeup(struct perf_output_handle *handle)
2650{
2651 atomic_set(&handle->data->poll, POLL_IN);
2652
2653 if (handle->nmi) {
2654 handle->event->pending_wakeup = 1;
2655 perf_pending_queue(&handle->event->pending,
2656 perf_pending_event);
2657 } else
2658 perf_event_wakeup(handle->event);
2659}
2660
2661/*
2662 * Curious locking construct.
2663 *
2664 * We need to ensure a later event_id doesn't publish a head when a former
2665 * event_id isn't done writing. However since we need to deal with NMIs we
2666 * cannot fully serialize things.
2667 *
2668 * What we do is serialize between CPUs so we only have to deal with NMI
2669 * nesting on a single CPU.
2670 *
2671 * We only publish the head (and generate a wakeup) when the outer-most
2672 * event_id completes.
2673 */
2674static void perf_output_lock(struct perf_output_handle *handle)
2675{
2676 struct perf_mmap_data *data = handle->data;
2677 int cpu;
2678
2679 handle->locked = 0;
2680
2681 local_irq_save(handle->flags);
2682 cpu = smp_processor_id();
2683
2684 if (in_nmi() && atomic_read(&data->lock) == cpu)
2685 return;
2686
2687 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2688 cpu_relax();
2689
2690 handle->locked = 1;
2691}
2692
2693static void perf_output_unlock(struct perf_output_handle *handle)
2694{
2695 struct perf_mmap_data *data = handle->data;
2696 unsigned long head;
2697 int cpu;
2698
2699 data->done_head = data->head;
2700
2701 if (!handle->locked)
2702 goto out;
2703
2704again:
2705 /*
2706 * The xchg implies a full barrier that ensures all writes are done
2707 * before we publish the new head, matched by a rmb() in userspace when
2708 * reading this position.
2709 */
2710 while ((head = atomic_long_xchg(&data->done_head, 0)))
2711 data->user_page->data_head = head;
2712
2713 /*
2714 * NMI can happen here, which means we can miss a done_head update.
2715 */
2716
2717 cpu = atomic_xchg(&data->lock, -1);
2718 WARN_ON_ONCE(cpu != smp_processor_id());
2719
2720 /*
2721 * Therefore we have to validate we did not indeed do so.
2722 */
2723 if (unlikely(atomic_long_read(&data->done_head))) {
2724 /*
2725 * Since we had it locked, we can lock it again.
2726 */
2727 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
2728 cpu_relax();
2729
2730 goto again;
2731 }
2732
2733 if (atomic_xchg(&data->wakeup, 0))
2734 perf_output_wakeup(handle);
2735out:
2736 local_irq_restore(handle->flags);
2737}
2738
2739void perf_output_copy(struct perf_output_handle *handle,
2740 const void *buf, unsigned int len)
2741{
2742 unsigned int pages_mask;
2743 unsigned long offset;
2744 unsigned int size;
2745 void **pages;
2746
2747 offset = handle->offset;
2748 pages_mask = handle->data->nr_pages - 1;
2749 pages = handle->data->data_pages;
2750
2751 do {
2752 unsigned long page_offset;
2753 unsigned long page_size;
2754 int nr;
2755
2756 nr = (offset >> PAGE_SHIFT) & pages_mask;
2757 page_size = 1UL << (handle->data->data_order + PAGE_SHIFT);
2758 page_offset = offset & (page_size - 1);
2759 size = min_t(unsigned int, page_size - page_offset, len);
2760
2761 memcpy(pages[nr] + page_offset, buf, size);
2762
2763 len -= size;
2764 buf += size;
2765 offset += size;
2766 } while (len);
2767
2768 handle->offset = offset;
2769
2770 /*
2771 * Check we didn't copy past our reservation window, taking the
2772 * possible unsigned int wrap into account.
2773 */
2774 WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0);
2775}
2776
2777int perf_output_begin(struct perf_output_handle *handle,
2778 struct perf_event *event, unsigned int size,
2779 int nmi, int sample)
2780{
2781 struct perf_event *output_event;
2782 struct perf_mmap_data *data;
2783 unsigned long tail, offset, head;
2784 int have_lost;
2785 struct {
2786 struct perf_event_header header;
2787 u64 id;
2788 u64 lost;
2789 } lost_event;
2790
2791 rcu_read_lock();
2792 /*
2793 * For inherited events we send all the output towards the parent.
2794 */
2795 if (event->parent)
2796 event = event->parent;
2797
2798 output_event = rcu_dereference(event->output);
2799 if (output_event)
2800 event = output_event;
2801
2802 data = rcu_dereference(event->data);
2803 if (!data)
2804 goto out;
2805
2806 handle->data = data;
2807 handle->event = event;
2808 handle->nmi = nmi;
2809 handle->sample = sample;
2810
2811 if (!data->nr_pages)
2812 goto fail;
2813
2814 have_lost = atomic_read(&data->lost);
2815 if (have_lost)
2816 size += sizeof(lost_event);
2817
2818 perf_output_lock(handle);
2819
2820 do {
2821 /*
2822 * Userspace could choose to issue a mb() before updating the
2823 * tail pointer. So that all reads will be completed before the
2824 * write is issued.
2825 */
2826 tail = ACCESS_ONCE(data->user_page->data_tail);
2827 smp_rmb();
2828 offset = head = atomic_long_read(&data->head);
2829 head += size;
2830 if (unlikely(!perf_output_space(data, tail, offset, head)))
2831 goto fail;
2832 } while (atomic_long_cmpxchg(&data->head, offset, head) != offset);
2833
2834 handle->offset = offset;
2835 handle->head = head;
2836
2837 if (head - tail > data->watermark)
2838 atomic_set(&data->wakeup, 1);
2839
2840 if (have_lost) {
2841 lost_event.header.type = PERF_RECORD_LOST;
2842 lost_event.header.misc = 0;
2843 lost_event.header.size = sizeof(lost_event);
2844 lost_event.id = event->id;
2845 lost_event.lost = atomic_xchg(&data->lost, 0);
2846
2847 perf_output_put(handle, lost_event);
2848 }
2849
2850 return 0;
2851
2852fail:
2853 atomic_inc(&data->lost);
2854 perf_output_unlock(handle);
2855out:
2856 rcu_read_unlock();
2857
2858 return -ENOSPC;
2859}
2860
2861void perf_output_end(struct perf_output_handle *handle)
2862{
2863 struct perf_event *event = handle->event;
2864 struct perf_mmap_data *data = handle->data;
2865
2866 int wakeup_events = event->attr.wakeup_events;
2867
2868 if (handle->sample && wakeup_events) {
2869 int events = atomic_inc_return(&data->events);
2870 if (events >= wakeup_events) {
2871 atomic_sub(wakeup_events, &data->events);
2872 atomic_set(&data->wakeup, 1);
2873 }
2874 }
2875
2876 perf_output_unlock(handle);
2877 rcu_read_unlock();
2878}
2879
2880static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
2881{
2882 /*
2883 * only top level events have the pid namespace they were created in
2884 */
2885 if (event->parent)
2886 event = event->parent;
2887
2888 return task_tgid_nr_ns(p, event->ns);
2889}
2890
2891static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
2892{
2893 /*
2894 * only top level events have the pid namespace they were created in
2895 */
2896 if (event->parent)
2897 event = event->parent;
2898
2899 return task_pid_nr_ns(p, event->ns);
2900}
2901
2902static void perf_output_read_one(struct perf_output_handle *handle,
2903 struct perf_event *event)
2904{
2905 u64 read_format = event->attr.read_format;
2906 u64 values[4];
2907 int n = 0;
2908
2909 values[n++] = atomic64_read(&event->count);
2910 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
2911 values[n++] = event->total_time_enabled +
2912 atomic64_read(&event->child_total_time_enabled);
2913 }
2914 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
2915 values[n++] = event->total_time_running +
2916 atomic64_read(&event->child_total_time_running);
2917 }
2918 if (read_format & PERF_FORMAT_ID)
2919 values[n++] = primary_event_id(event);
2920
2921 perf_output_copy(handle, values, n * sizeof(u64));
2922}
2923
2924/*
2925 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
2926 */
2927static void perf_output_read_group(struct perf_output_handle *handle,
2928 struct perf_event *event)
2929{
2930 struct perf_event *leader = event->group_leader, *sub;
2931 u64 read_format = event->attr.read_format;
2932 u64 values[5];
2933 int n = 0;
2934
2935 values[n++] = 1 + leader->nr_siblings;
2936
2937 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
2938 values[n++] = leader->total_time_enabled;
2939
2940 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
2941 values[n++] = leader->total_time_running;
2942
2943 if (leader != event)
2944 leader->pmu->read(leader);
2945
2946 values[n++] = atomic64_read(&leader->count);
2947 if (read_format & PERF_FORMAT_ID)
2948 values[n++] = primary_event_id(leader);
2949
2950 perf_output_copy(handle, values, n * sizeof(u64));
2951
2952 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
2953 n = 0;
2954
2955 if (sub != event)
2956 sub->pmu->read(sub);
2957
2958 values[n++] = atomic64_read(&sub->count);
2959 if (read_format & PERF_FORMAT_ID)
2960 values[n++] = primary_event_id(sub);
2961
2962 perf_output_copy(handle, values, n * sizeof(u64));
2963 }
2964}
2965
2966static void perf_output_read(struct perf_output_handle *handle,
2967 struct perf_event *event)
2968{
2969 if (event->attr.read_format & PERF_FORMAT_GROUP)
2970 perf_output_read_group(handle, event);
2971 else
2972 perf_output_read_one(handle, event);
2973}
2974
2975void perf_output_sample(struct perf_output_handle *handle,
2976 struct perf_event_header *header,
2977 struct perf_sample_data *data,
2978 struct perf_event *event)
2979{
2980 u64 sample_type = data->type;
2981
2982 perf_output_put(handle, *header);
2983
2984 if (sample_type & PERF_SAMPLE_IP)
2985 perf_output_put(handle, data->ip);
2986
2987 if (sample_type & PERF_SAMPLE_TID)
2988 perf_output_put(handle, data->tid_entry);
2989
2990 if (sample_type & PERF_SAMPLE_TIME)
2991 perf_output_put(handle, data->time);
2992
2993 if (sample_type & PERF_SAMPLE_ADDR)
2994 perf_output_put(handle, data->addr);
2995
2996 if (sample_type & PERF_SAMPLE_ID)
2997 perf_output_put(handle, data->id);
2998
2999 if (sample_type & PERF_SAMPLE_STREAM_ID)
3000 perf_output_put(handle, data->stream_id);
3001
3002 if (sample_type & PERF_SAMPLE_CPU)
3003 perf_output_put(handle, data->cpu_entry);
3004
3005 if (sample_type & PERF_SAMPLE_PERIOD)
3006 perf_output_put(handle, data->period);
3007
3008 if (sample_type & PERF_SAMPLE_READ)
3009 perf_output_read(handle, event);
3010
3011 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3012 if (data->callchain) {
3013 int size = 1;
3014
3015 if (data->callchain)
3016 size += data->callchain->nr;
3017
3018 size *= sizeof(u64);
3019
3020 perf_output_copy(handle, data->callchain, size);
3021 } else {
3022 u64 nr = 0;
3023 perf_output_put(handle, nr);
3024 }
3025 }
3026
3027 if (sample_type & PERF_SAMPLE_RAW) {
3028 if (data->raw) {
3029 perf_output_put(handle, data->raw->size);
3030 perf_output_copy(handle, data->raw->data,
3031 data->raw->size);
3032 } else {
3033 struct {
3034 u32 size;
3035 u32 data;
3036 } raw = {
3037 .size = sizeof(u32),
3038 .data = 0,
3039 };
3040 perf_output_put(handle, raw);
3041 }
3042 }
3043}
3044
3045void perf_prepare_sample(struct perf_event_header *header,
3046 struct perf_sample_data *data,
3047 struct perf_event *event,
3048 struct pt_regs *regs)
3049{
3050 u64 sample_type = event->attr.sample_type;
3051
3052 data->type = sample_type;
3053
3054 header->type = PERF_RECORD_SAMPLE;
3055 header->size = sizeof(*header);
3056
3057 header->misc = 0;
3058 header->misc |= perf_misc_flags(regs);
3059
3060 if (sample_type & PERF_SAMPLE_IP) {
3061 data->ip = perf_instruction_pointer(regs);
3062
3063 header->size += sizeof(data->ip);
3064 }
3065
3066 if (sample_type & PERF_SAMPLE_TID) {
3067 /* namespace issues */
3068 data->tid_entry.pid = perf_event_pid(event, current);
3069 data->tid_entry.tid = perf_event_tid(event, current);
3070
3071 header->size += sizeof(data->tid_entry);
3072 }
3073
3074 if (sample_type & PERF_SAMPLE_TIME) {
3075 data->time = perf_clock();
3076
3077 header->size += sizeof(data->time);
3078 }
3079
3080 if (sample_type & PERF_SAMPLE_ADDR)
3081 header->size += sizeof(data->addr);
3082
3083 if (sample_type & PERF_SAMPLE_ID) {
3084 data->id = primary_event_id(event);
3085
3086 header->size += sizeof(data->id);
3087 }
3088
3089 if (sample_type & PERF_SAMPLE_STREAM_ID) {
3090 data->stream_id = event->id;
3091
3092 header->size += sizeof(data->stream_id);
3093 }
3094
3095 if (sample_type & PERF_SAMPLE_CPU) {
3096 data->cpu_entry.cpu = raw_smp_processor_id();
3097 data->cpu_entry.reserved = 0;
3098
3099 header->size += sizeof(data->cpu_entry);
3100 }
3101
3102 if (sample_type & PERF_SAMPLE_PERIOD)
3103 header->size += sizeof(data->period);
3104
3105 if (sample_type & PERF_SAMPLE_READ)
3106 header->size += perf_event_read_size(event);
3107
3108 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3109 int size = 1;
3110
3111 data->callchain = perf_callchain(regs);
3112
3113 if (data->callchain)
3114 size += data->callchain->nr;
3115
3116 header->size += size * sizeof(u64);
3117 }
3118
3119 if (sample_type & PERF_SAMPLE_RAW) {
3120 int size = sizeof(u32);
3121
3122 if (data->raw)
3123 size += data->raw->size;
3124 else
3125 size += sizeof(u32);
3126
3127 WARN_ON_ONCE(size & (sizeof(u64)-1));
3128 header->size += size;
3129 }
3130}
3131
3132static void perf_event_output(struct perf_event *event, int nmi,
3133 struct perf_sample_data *data,
3134 struct pt_regs *regs)
3135{
3136 struct perf_output_handle handle;
3137 struct perf_event_header header;
3138
3139 perf_prepare_sample(&header, data, event, regs);
3140
3141 if (perf_output_begin(&handle, event, header.size, nmi, 1))
3142 return;
3143
3144 perf_output_sample(&handle, &header, data, event);
3145
3146 perf_output_end(&handle);
3147}
3148
3149/*
3150 * read event_id
3151 */
3152
3153struct perf_read_event {
3154 struct perf_event_header header;
3155
3156 u32 pid;
3157 u32 tid;
3158};
3159
3160static void
3161perf_event_read_event(struct perf_event *event,
3162 struct task_struct *task)
3163{
3164 struct perf_output_handle handle;
3165 struct perf_read_event read_event = {
3166 .header = {
3167 .type = PERF_RECORD_READ,
3168 .misc = 0,
3169 .size = sizeof(read_event) + perf_event_read_size(event),
3170 },
3171 .pid = perf_event_pid(event, task),
3172 .tid = perf_event_tid(event, task),
3173 };
3174 int ret;
3175
3176 ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0);
3177 if (ret)
3178 return;
3179
3180 perf_output_put(&handle, read_event);
3181 perf_output_read(&handle, event);
3182
3183 perf_output_end(&handle);
3184}
3185
3186/*
3187 * task tracking -- fork/exit
3188 *
3189 * enabled by: attr.comm | attr.mmap | attr.task
3190 */
3191
3192struct perf_task_event {
3193 struct task_struct *task;
3194 struct perf_event_context *task_ctx;
3195
3196 struct {
3197 struct perf_event_header header;
3198
3199 u32 pid;
3200 u32 ppid;
3201 u32 tid;
3202 u32 ptid;
3203 u64 time;
3204 } event_id;
3205};
3206
3207static void perf_event_task_output(struct perf_event *event,
3208 struct perf_task_event *task_event)
3209{
3210 struct perf_output_handle handle;
3211 int size;
3212 struct task_struct *task = task_event->task;
3213 int ret;
3214
3215 size = task_event->event_id.header.size;
3216 ret = perf_output_begin(&handle, event, size, 0, 0);
3217
3218 if (ret)
3219 return;
3220
3221 task_event->event_id.pid = perf_event_pid(event, task);
3222 task_event->event_id.ppid = perf_event_pid(event, current);
3223
3224 task_event->event_id.tid = perf_event_tid(event, task);
3225 task_event->event_id.ptid = perf_event_tid(event, current);
3226
3227 task_event->event_id.time = perf_clock();
3228
3229 perf_output_put(&handle, task_event->event_id);
3230
3231 perf_output_end(&handle);
3232}
3233
3234static int perf_event_task_match(struct perf_event *event)
3235{
3236 if (event->attr.comm || event->attr.mmap || event->attr.task)
3237 return 1;
3238
3239 return 0;
3240}
3241
3242static void perf_event_task_ctx(struct perf_event_context *ctx,
3243 struct perf_task_event *task_event)
3244{
3245 struct perf_event *event;
3246
3247 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3248 return;
3249
3250 rcu_read_lock();
3251 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3252 if (perf_event_task_match(event))
3253 perf_event_task_output(event, task_event);
3254 }
3255 rcu_read_unlock();
3256}
3257
3258static void perf_event_task_event(struct perf_task_event *task_event)
3259{
3260 struct perf_cpu_context *cpuctx;
3261 struct perf_event_context *ctx = task_event->task_ctx;
3262
3263 cpuctx = &get_cpu_var(perf_cpu_context);
3264 perf_event_task_ctx(&cpuctx->ctx, task_event);
3265 put_cpu_var(perf_cpu_context);
3266
3267 rcu_read_lock();
3268 if (!ctx)
3269 ctx = rcu_dereference(task_event->task->perf_event_ctxp);
3270 if (ctx)
3271 perf_event_task_ctx(ctx, task_event);
3272 rcu_read_unlock();
3273}
3274
3275static void perf_event_task(struct task_struct *task,
3276 struct perf_event_context *task_ctx,
3277 int new)
3278{
3279 struct perf_task_event task_event;
3280
3281 if (!atomic_read(&nr_comm_events) &&
3282 !atomic_read(&nr_mmap_events) &&
3283 !atomic_read(&nr_task_events))
3284 return;
3285
3286 task_event = (struct perf_task_event){
3287 .task = task,
3288 .task_ctx = task_ctx,
3289 .event_id = {
3290 .header = {
3291 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
3292 .misc = 0,
3293 .size = sizeof(task_event.event_id),
3294 },
3295 /* .pid */
3296 /* .ppid */
3297 /* .tid */
3298 /* .ptid */
3299 },
3300 };
3301
3302 perf_event_task_event(&task_event);
3303}
3304
3305void perf_event_fork(struct task_struct *task)
3306{
3307 perf_event_task(task, NULL, 1);
3308}
3309
3310/*
3311 * comm tracking
3312 */
3313
3314struct perf_comm_event {
3315 struct task_struct *task;
3316 char *comm;
3317 int comm_size;
3318
3319 struct {
3320 struct perf_event_header header;
3321
3322 u32 pid;
3323 u32 tid;
3324 } event_id;
3325};
3326
3327static void perf_event_comm_output(struct perf_event *event,
3328 struct perf_comm_event *comm_event)
3329{
3330 struct perf_output_handle handle;
3331 int size = comm_event->event_id.header.size;
3332 int ret = perf_output_begin(&handle, event, size, 0, 0);
3333
3334 if (ret)
3335 return;
3336
3337 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
3338 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
3339
3340 perf_output_put(&handle, comm_event->event_id);
3341 perf_output_copy(&handle, comm_event->comm,
3342 comm_event->comm_size);
3343 perf_output_end(&handle);
3344}
3345
3346static int perf_event_comm_match(struct perf_event *event)
3347{
3348 if (event->attr.comm)
3349 return 1;
3350
3351 return 0;
3352}
3353
3354static void perf_event_comm_ctx(struct perf_event_context *ctx,
3355 struct perf_comm_event *comm_event)
3356{
3357 struct perf_event *event;
3358
3359 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3360 return;
3361
3362 rcu_read_lock();
3363 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3364 if (perf_event_comm_match(event))
3365 perf_event_comm_output(event, comm_event);
3366 }
3367 rcu_read_unlock();
3368}
3369
3370static void perf_event_comm_event(struct perf_comm_event *comm_event)
3371{
3372 struct perf_cpu_context *cpuctx;
3373 struct perf_event_context *ctx;
3374 unsigned int size;
3375 char comm[TASK_COMM_LEN];
3376
3377 memset(comm, 0, sizeof(comm));
3378 strncpy(comm, comm_event->task->comm, sizeof(comm));
3379 size = ALIGN(strlen(comm)+1, sizeof(u64));
3380
3381 comm_event->comm = comm;
3382 comm_event->comm_size = size;
3383
3384 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
3385
3386 cpuctx = &get_cpu_var(perf_cpu_context);
3387 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
3388 put_cpu_var(perf_cpu_context);
3389
3390 rcu_read_lock();
3391 /*
3392 * doesn't really matter which of the child contexts the
3393 * events ends up in.
3394 */
3395 ctx = rcu_dereference(current->perf_event_ctxp);
3396 if (ctx)
3397 perf_event_comm_ctx(ctx, comm_event);
3398 rcu_read_unlock();
3399}
3400
3401void perf_event_comm(struct task_struct *task)
3402{
3403 struct perf_comm_event comm_event;
3404
3405 if (task->perf_event_ctxp)
3406 perf_event_enable_on_exec(task);
3407
3408 if (!atomic_read(&nr_comm_events))
3409 return;
3410
3411 comm_event = (struct perf_comm_event){
3412 .task = task,
3413 /* .comm */
3414 /* .comm_size */
3415 .event_id = {
3416 .header = {
3417 .type = PERF_RECORD_COMM,
3418 .misc = 0,
3419 /* .size */
3420 },
3421 /* .pid */
3422 /* .tid */
3423 },
3424 };
3425
3426 perf_event_comm_event(&comm_event);
3427}
3428
3429/*
3430 * mmap tracking
3431 */
3432
3433struct perf_mmap_event {
3434 struct vm_area_struct *vma;
3435
3436 const char *file_name;
3437 int file_size;
3438
3439 struct {
3440 struct perf_event_header header;
3441
3442 u32 pid;
3443 u32 tid;
3444 u64 start;
3445 u64 len;
3446 u64 pgoff;
3447 } event_id;
3448};
3449
3450static void perf_event_mmap_output(struct perf_event *event,
3451 struct perf_mmap_event *mmap_event)
3452{
3453 struct perf_output_handle handle;
3454 int size = mmap_event->event_id.header.size;
3455 int ret = perf_output_begin(&handle, event, size, 0, 0);
3456
3457 if (ret)
3458 return;
3459
3460 mmap_event->event_id.pid = perf_event_pid(event, current);
3461 mmap_event->event_id.tid = perf_event_tid(event, current);
3462
3463 perf_output_put(&handle, mmap_event->event_id);
3464 perf_output_copy(&handle, mmap_event->file_name,
3465 mmap_event->file_size);
3466 perf_output_end(&handle);
3467}
3468
3469static int perf_event_mmap_match(struct perf_event *event,
3470 struct perf_mmap_event *mmap_event)
3471{
3472 if (event->attr.mmap)
3473 return 1;
3474
3475 return 0;
3476}
3477
3478static void perf_event_mmap_ctx(struct perf_event_context *ctx,
3479 struct perf_mmap_event *mmap_event)
3480{
3481 struct perf_event *event;
3482
3483 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3484 return;
3485
3486 rcu_read_lock();
3487 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3488 if (perf_event_mmap_match(event, mmap_event))
3489 perf_event_mmap_output(event, mmap_event);
3490 }
3491 rcu_read_unlock();
3492}
3493
3494static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
3495{
3496 struct perf_cpu_context *cpuctx;
3497 struct perf_event_context *ctx;
3498 struct vm_area_struct *vma = mmap_event->vma;
3499 struct file *file = vma->vm_file;
3500 unsigned int size;
3501 char tmp[16];
3502 char *buf = NULL;
3503 const char *name;
3504
3505 memset(tmp, 0, sizeof(tmp));
3506
3507 if (file) {
3508 /*
3509 * d_path works from the end of the buffer backwards, so we
3510 * need to add enough zero bytes after the string to handle
3511 * the 64bit alignment we do later.
3512 */
3513 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
3514 if (!buf) {
3515 name = strncpy(tmp, "//enomem", sizeof(tmp));
3516 goto got_name;
3517 }
3518 name = d_path(&file->f_path, buf, PATH_MAX);
3519 if (IS_ERR(name)) {
3520 name = strncpy(tmp, "//toolong", sizeof(tmp));
3521 goto got_name;
3522 }
3523 } else {
3524 if (arch_vma_name(mmap_event->vma)) {
3525 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
3526 sizeof(tmp));
3527 goto got_name;
3528 }
3529
3530 if (!vma->vm_mm) {
3531 name = strncpy(tmp, "[vdso]", sizeof(tmp));
3532 goto got_name;
3533 }
3534
3535 name = strncpy(tmp, "//anon", sizeof(tmp));
3536 goto got_name;
3537 }
3538
3539got_name:
3540 size = ALIGN(strlen(name)+1, sizeof(u64));
3541
3542 mmap_event->file_name = name;
3543 mmap_event->file_size = size;
3544
3545 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
3546
3547 cpuctx = &get_cpu_var(perf_cpu_context);
3548 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event);
3549 put_cpu_var(perf_cpu_context);
3550
3551 rcu_read_lock();
3552 /*
3553 * doesn't really matter which of the child contexts the
3554 * events ends up in.
3555 */
3556 ctx = rcu_dereference(current->perf_event_ctxp);
3557 if (ctx)
3558 perf_event_mmap_ctx(ctx, mmap_event);
3559 rcu_read_unlock();
3560
3561 kfree(buf);
3562}
3563
3564void __perf_event_mmap(struct vm_area_struct *vma)
3565{
3566 struct perf_mmap_event mmap_event;
3567
3568 if (!atomic_read(&nr_mmap_events))
3569 return;
3570
3571 mmap_event = (struct perf_mmap_event){
3572 .vma = vma,
3573 /* .file_name */
3574 /* .file_size */
3575 .event_id = {
3576 .header = {
3577 .type = PERF_RECORD_MMAP,
3578 .misc = 0,
3579 /* .size */
3580 },
3581 /* .pid */
3582 /* .tid */
3583 .start = vma->vm_start,
3584 .len = vma->vm_end - vma->vm_start,
3585 .pgoff = vma->vm_pgoff,
3586 },
3587 };
3588
3589 perf_event_mmap_event(&mmap_event);
3590}
3591
3592/*
3593 * IRQ throttle logging
3594 */
3595
3596static void perf_log_throttle(struct perf_event *event, int enable)
3597{
3598 struct perf_output_handle handle;
3599 int ret;
3600
3601 struct {
3602 struct perf_event_header header;
3603 u64 time;
3604 u64 id;
3605 u64 stream_id;
3606 } throttle_event = {
3607 .header = {
3608 .type = PERF_RECORD_THROTTLE,
3609 .misc = 0,
3610 .size = sizeof(throttle_event),
3611 },
3612 .time = perf_clock(),
3613 .id = primary_event_id(event),
3614 .stream_id = event->id,
3615 };
3616
3617 if (enable)
3618 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
3619
3620 ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0);
3621 if (ret)
3622 return;
3623
3624 perf_output_put(&handle, throttle_event);
3625 perf_output_end(&handle);
3626}
3627
3628/*
3629 * Generic event overflow handling, sampling.
3630 */
3631
3632static int __perf_event_overflow(struct perf_event *event, int nmi,
3633 int throttle, struct perf_sample_data *data,
3634 struct pt_regs *regs)
3635{
3636 int events = atomic_read(&event->event_limit);
3637 struct hw_perf_event *hwc = &event->hw;
3638 int ret = 0;
3639
3640 throttle = (throttle && event->pmu->unthrottle != NULL);
3641
3642 if (!throttle) {
3643 hwc->interrupts++;
3644 } else {
3645 if (hwc->interrupts != MAX_INTERRUPTS) {
3646 hwc->interrupts++;
3647 if (HZ * hwc->interrupts >
3648 (u64)sysctl_perf_event_sample_rate) {
3649 hwc->interrupts = MAX_INTERRUPTS;
3650 perf_log_throttle(event, 0);
3651 ret = 1;
3652 }
3653 } else {
3654 /*
3655 * Keep re-disabling events even though on the previous
3656 * pass we disabled it - just in case we raced with a
3657 * sched-in and the event got enabled again:
3658 */
3659 ret = 1;
3660 }
3661 }
3662
3663 if (event->attr.freq) {
3664 u64 now = perf_clock();
3665 s64 delta = now - hwc->freq_stamp;
3666
3667 hwc->freq_stamp = now;
3668
3669 if (delta > 0 && delta < TICK_NSEC)
3670 perf_adjust_period(event, NSEC_PER_SEC / (int)delta);
3671 }
3672
3673 /*
3674 * XXX event_limit might not quite work as expected on inherited
3675 * events
3676 */
3677
3678 event->pending_kill = POLL_IN;
3679 if (events && atomic_dec_and_test(&event->event_limit)) {
3680 ret = 1;
3681 event->pending_kill = POLL_HUP;
3682 if (nmi) {
3683 event->pending_disable = 1;
3684 perf_pending_queue(&event->pending,
3685 perf_pending_event);
3686 } else
3687 perf_event_disable(event);
3688 }
3689
3690 perf_event_output(event, nmi, data, regs);
3691 return ret;
3692}
3693
3694int perf_event_overflow(struct perf_event *event, int nmi,
3695 struct perf_sample_data *data,
3696 struct pt_regs *regs)
3697{
3698 return __perf_event_overflow(event, nmi, 1, data, regs);
3699}
3700
3701/*
3702 * Generic software event infrastructure
3703 */
3704
3705/*
3706 * We directly increment event->count and keep a second value in
3707 * event->hw.period_left to count intervals. This period event
3708 * is kept in the range [-sample_period, 0] so that we can use the
3709 * sign as trigger.
3710 */
3711
3712static u64 perf_swevent_set_period(struct perf_event *event)
3713{
3714 struct hw_perf_event *hwc = &event->hw;
3715 u64 period = hwc->last_period;
3716 u64 nr, offset;
3717 s64 old, val;
3718
3719 hwc->last_period = hwc->sample_period;
3720
3721again:
3722 old = val = atomic64_read(&hwc->period_left);
3723 if (val < 0)
3724 return 0;
3725
3726 nr = div64_u64(period + val, period);
3727 offset = nr * period;
3728 val -= offset;
3729 if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
3730 goto again;
3731
3732 return nr;
3733}
3734
3735static void perf_swevent_overflow(struct perf_event *event,
3736 int nmi, struct perf_sample_data *data,
3737 struct pt_regs *regs)
3738{
3739 struct hw_perf_event *hwc = &event->hw;
3740 int throttle = 0;
3741 u64 overflow;
3742
3743 data->period = event->hw.last_period;
3744 overflow = perf_swevent_set_period(event);
3745
3746 if (hwc->interrupts == MAX_INTERRUPTS)
3747 return;
3748
3749 for (; overflow; overflow--) {
3750 if (__perf_event_overflow(event, nmi, throttle,
3751 data, regs)) {
3752 /*
3753 * We inhibit the overflow from happening when
3754 * hwc->interrupts == MAX_INTERRUPTS.
3755 */
3756 break;
3757 }
3758 throttle = 1;
3759 }
3760}
3761
3762static void perf_swevent_unthrottle(struct perf_event *event)
3763{
3764 /*
3765 * Nothing to do, we already reset hwc->interrupts.
3766 */
3767}
3768
3769static void perf_swevent_add(struct perf_event *event, u64 nr,
3770 int nmi, struct perf_sample_data *data,
3771 struct pt_regs *regs)
3772{
3773 struct hw_perf_event *hwc = &event->hw;
3774
3775 atomic64_add(nr, &event->count);
3776
3777 if (!hwc->sample_period)
3778 return;
3779
3780 if (!regs)
3781 return;
3782
3783 if (!atomic64_add_negative(nr, &hwc->period_left))
3784 perf_swevent_overflow(event, nmi, data, regs);
3785}
3786
3787static int perf_swevent_is_counting(struct perf_event *event)
3788{
3789 /*
3790 * The event is active, we're good!
3791 */
3792 if (event->state == PERF_EVENT_STATE_ACTIVE)
3793 return 1;
3794
3795 /*
3796 * The event is off/error, not counting.
3797 */
3798 if (event->state != PERF_EVENT_STATE_INACTIVE)
3799 return 0;
3800
3801 /*
3802 * The event is inactive, if the context is active
3803 * we're part of a group that didn't make it on the 'pmu',
3804 * not counting.
3805 */
3806 if (event->ctx->is_active)
3807 return 0;
3808
3809 /*
3810 * We're inactive and the context is too, this means the
3811 * task is scheduled out, we're counting events that happen
3812 * to us, like migration events.
3813 */
3814 return 1;
3815}
3816
3817static int perf_tp_event_match(struct perf_event *event,
3818 struct perf_sample_data *data);
3819
3820static int perf_swevent_match(struct perf_event *event,
3821 enum perf_type_id type,
3822 u32 event_id,
3823 struct perf_sample_data *data,
3824 struct pt_regs *regs)
3825{
3826 if (!perf_swevent_is_counting(event))
3827 return 0;
3828
3829 if (event->attr.type != type)
3830 return 0;
3831 if (event->attr.config != event_id)
3832 return 0;
3833
3834 if (regs) {
3835 if (event->attr.exclude_user && user_mode(regs))
3836 return 0;
3837
3838 if (event->attr.exclude_kernel && !user_mode(regs))
3839 return 0;
3840 }
3841
3842 if (event->attr.type == PERF_TYPE_TRACEPOINT &&
3843 !perf_tp_event_match(event, data))
3844 return 0;
3845
3846 return 1;
3847}
3848
3849static void perf_swevent_ctx_event(struct perf_event_context *ctx,
3850 enum perf_type_id type,
3851 u32 event_id, u64 nr, int nmi,
3852 struct perf_sample_data *data,
3853 struct pt_regs *regs)
3854{
3855 struct perf_event *event;
3856
3857 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
3858 return;
3859
3860 rcu_read_lock();
3861 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3862 if (perf_swevent_match(event, type, event_id, data, regs))
3863 perf_swevent_add(event, nr, nmi, data, regs);
3864 }
3865 rcu_read_unlock();
3866}
3867
3868static int *perf_swevent_recursion_context(struct perf_cpu_context *cpuctx)
3869{
3870 if (in_nmi())
3871 return &cpuctx->recursion[3];
3872
3873 if (in_irq())
3874 return &cpuctx->recursion[2];
3875
3876 if (in_softirq())
3877 return &cpuctx->recursion[1];
3878
3879 return &cpuctx->recursion[0];
3880}
3881
3882static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
3883 u64 nr, int nmi,
3884 struct perf_sample_data *data,
3885 struct pt_regs *regs)
3886{
3887 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
3888 int *recursion = perf_swevent_recursion_context(cpuctx);
3889 struct perf_event_context *ctx;
3890
3891 if (*recursion)
3892 goto out;
3893
3894 (*recursion)++;
3895 barrier();
3896
3897 perf_swevent_ctx_event(&cpuctx->ctx, type, event_id,
3898 nr, nmi, data, regs);
3899 rcu_read_lock();
3900 /*
3901 * doesn't really matter which of the child contexts the
3902 * events ends up in.
3903 */
3904 ctx = rcu_dereference(current->perf_event_ctxp);
3905 if (ctx)
3906 perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs);
3907 rcu_read_unlock();
3908
3909 barrier();
3910 (*recursion)--;
3911
3912out:
3913 put_cpu_var(perf_cpu_context);
3914}
3915
3916void __perf_sw_event(u32 event_id, u64 nr, int nmi,
3917 struct pt_regs *regs, u64 addr)
3918{
3919 struct perf_sample_data data = {
3920 .addr = addr,
3921 };
3922
3923 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi,
3924 &data, regs);
3925}
3926
3927static void perf_swevent_read(struct perf_event *event)
3928{
3929}
3930
3931static int perf_swevent_enable(struct perf_event *event)
3932{
3933 struct hw_perf_event *hwc = &event->hw;
3934
3935 if (hwc->sample_period) {
3936 hwc->last_period = hwc->sample_period;
3937 perf_swevent_set_period(event);
3938 }
3939 return 0;
3940}
3941
3942static void perf_swevent_disable(struct perf_event *event)
3943{
3944}
3945
3946static const struct pmu perf_ops_generic = {
3947 .enable = perf_swevent_enable,
3948 .disable = perf_swevent_disable,
3949 .read = perf_swevent_read,
3950 .unthrottle = perf_swevent_unthrottle,
3951};
3952
3953/*
3954 * hrtimer based swevent callback
3955 */
3956
3957static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
3958{
3959 enum hrtimer_restart ret = HRTIMER_RESTART;
3960 struct perf_sample_data data;
3961 struct pt_regs *regs;
3962 struct perf_event *event;
3963 u64 period;
3964
3965 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
3966 event->pmu->read(event);
3967
3968 data.addr = 0;
3969 regs = get_irq_regs();
3970 /*
3971 * In case we exclude kernel IPs or are somehow not in interrupt
3972 * context, provide the next best thing, the user IP.
3973 */
3974 if ((event->attr.exclude_kernel || !regs) &&
3975 !event->attr.exclude_user)
3976 regs = task_pt_regs(current);
3977
3978 if (regs) {
3979 if (perf_event_overflow(event, 0, &data, regs))
3980 ret = HRTIMER_NORESTART;
3981 }
3982
3983 period = max_t(u64, 10000, event->hw.sample_period);
3984 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
3985
3986 return ret;
3987}
3988
3989/*
3990 * Software event: cpu wall time clock
3991 */
3992
3993static void cpu_clock_perf_event_update(struct perf_event *event)
3994{
3995 int cpu = raw_smp_processor_id();
3996 s64 prev;
3997 u64 now;
3998
3999 now = cpu_clock(cpu);
4000 prev = atomic64_read(&event->hw.prev_count);
4001 atomic64_set(&event->hw.prev_count, now);
4002 atomic64_add(now - prev, &event->count);
4003}
4004
4005static int cpu_clock_perf_event_enable(struct perf_event *event)
4006{
4007 struct hw_perf_event *hwc = &event->hw;
4008 int cpu = raw_smp_processor_id();
4009
4010 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
4011 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4012 hwc->hrtimer.function = perf_swevent_hrtimer;
4013 if (hwc->sample_period) {
4014 u64 period = max_t(u64, 10000, hwc->sample_period);
4015 __hrtimer_start_range_ns(&hwc->hrtimer,
4016 ns_to_ktime(period), 0,
4017 HRTIMER_MODE_REL, 0);
4018 }
4019
4020 return 0;
4021}
4022
4023static void cpu_clock_perf_event_disable(struct perf_event *event)
4024{
4025 if (event->hw.sample_period)
4026 hrtimer_cancel(&event->hw.hrtimer);
4027 cpu_clock_perf_event_update(event);
4028}
4029
4030static void cpu_clock_perf_event_read(struct perf_event *event)
4031{
4032 cpu_clock_perf_event_update(event);
4033}
4034
4035static const struct pmu perf_ops_cpu_clock = {
4036 .enable = cpu_clock_perf_event_enable,
4037 .disable = cpu_clock_perf_event_disable,
4038 .read = cpu_clock_perf_event_read,
4039};
4040
4041/*
4042 * Software event: task time clock
4043 */
4044
4045static void task_clock_perf_event_update(struct perf_event *event, u64 now)
4046{
4047 u64 prev;
4048 s64 delta;
4049
4050 prev = atomic64_xchg(&event->hw.prev_count, now);
4051 delta = now - prev;
4052 atomic64_add(delta, &event->count);
4053}
4054
4055static int task_clock_perf_event_enable(struct perf_event *event)
4056{
4057 struct hw_perf_event *hwc = &event->hw;
4058 u64 now;
4059
4060 now = event->ctx->time;
4061
4062 atomic64_set(&hwc->prev_count, now);
4063 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
4064 hwc->hrtimer.function = perf_swevent_hrtimer;
4065 if (hwc->sample_period) {
4066 u64 period = max_t(u64, 10000, hwc->sample_period);
4067 __hrtimer_start_range_ns(&hwc->hrtimer,
4068 ns_to_ktime(period), 0,
4069 HRTIMER_MODE_REL, 0);
4070 }
4071
4072 return 0;
4073}
4074
4075static void task_clock_perf_event_disable(struct perf_event *event)
4076{
4077 if (event->hw.sample_period)
4078 hrtimer_cancel(&event->hw.hrtimer);
4079 task_clock_perf_event_update(event, event->ctx->time);
4080
4081}
4082
4083static void task_clock_perf_event_read(struct perf_event *event)
4084{
4085 u64 time;
4086
4087 if (!in_nmi()) {
4088 update_context_time(event->ctx);
4089 time = event->ctx->time;
4090 } else {
4091 u64 now = perf_clock();
4092 u64 delta = now - event->ctx->timestamp;
4093 time = event->ctx->time + delta;
4094 }
4095
4096 task_clock_perf_event_update(event, time);
4097}
4098
4099static const struct pmu perf_ops_task_clock = {
4100 .enable = task_clock_perf_event_enable,
4101 .disable = task_clock_perf_event_disable,
4102 .read = task_clock_perf_event_read,
4103};
4104
4105#ifdef CONFIG_EVENT_PROFILE
4106
4107void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
4108 int entry_size)
4109{
4110 struct perf_raw_record raw = {
4111 .size = entry_size,
4112 .data = record,
4113 };
4114
4115 struct perf_sample_data data = {
4116 .addr = addr,
4117 .raw = &raw,
4118 };
4119
4120 struct pt_regs *regs = get_irq_regs();
4121
4122 if (!regs)
4123 regs = task_pt_regs(current);
4124
4125 do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
4126 &data, regs);
4127}
4128EXPORT_SYMBOL_GPL(perf_tp_event);
4129
4130static int perf_tp_event_match(struct perf_event *event,
4131 struct perf_sample_data *data)
4132{
4133 void *record = data->raw->data;
4134
4135 if (likely(!event->filter) || filter_match_preds(event->filter, record))
4136 return 1;
4137 return 0;
4138}
4139
4140static void tp_perf_event_destroy(struct perf_event *event)
4141{
4142 ftrace_profile_disable(event->attr.config);
4143}
4144
4145static const struct pmu *tp_perf_event_init(struct perf_event *event)
4146{
4147 /*
4148 * Raw tracepoint data is a severe data leak, only allow root to
4149 * have these.
4150 */
4151 if ((event->attr.sample_type & PERF_SAMPLE_RAW) &&
4152 perf_paranoid_tracepoint_raw() &&
4153 !capable(CAP_SYS_ADMIN))
4154 return ERR_PTR(-EPERM);
4155
4156 if (ftrace_profile_enable(event->attr.config))
4157 return NULL;
4158
4159 event->destroy = tp_perf_event_destroy;
4160
4161 return &perf_ops_generic;
4162}
4163
4164static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4165{
4166 char *filter_str;
4167 int ret;
4168
4169 if (event->attr.type != PERF_TYPE_TRACEPOINT)
4170 return -EINVAL;
4171
4172 filter_str = strndup_user(arg, PAGE_SIZE);
4173 if (IS_ERR(filter_str))
4174 return PTR_ERR(filter_str);
4175
4176 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
4177
4178 kfree(filter_str);
4179 return ret;
4180}
4181
4182static void perf_event_free_filter(struct perf_event *event)
4183{
4184 ftrace_profile_free_filter(event);
4185}
4186
4187#else
4188
4189static int perf_tp_event_match(struct perf_event *event,
4190 struct perf_sample_data *data)
4191{
4192 return 1;
4193}
4194
4195static const struct pmu *tp_perf_event_init(struct perf_event *event)
4196{
4197 return NULL;
4198}
4199
4200static int perf_event_set_filter(struct perf_event *event, void __user *arg)
4201{
4202 return -ENOENT;
4203}
4204
4205static void perf_event_free_filter(struct perf_event *event)
4206{
4207}
4208
4209#endif /* CONFIG_EVENT_PROFILE */
4210
4211atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
4212
4213static void sw_perf_event_destroy(struct perf_event *event)
4214{
4215 u64 event_id = event->attr.config;
4216
4217 WARN_ON(event->parent);
4218
4219 atomic_dec(&perf_swevent_enabled[event_id]);
4220}
4221
4222static const struct pmu *sw_perf_event_init(struct perf_event *event)
4223{
4224 const struct pmu *pmu = NULL;
4225 u64 event_id = event->attr.config;
4226
4227 /*
4228 * Software events (currently) can't in general distinguish
4229 * between user, kernel and hypervisor events.
4230 * However, context switches and cpu migrations are considered
4231 * to be kernel events, and page faults are never hypervisor
4232 * events.
4233 */
4234 switch (event_id) {
4235 case PERF_COUNT_SW_CPU_CLOCK:
4236 pmu = &perf_ops_cpu_clock;
4237
4238 break;
4239 case PERF_COUNT_SW_TASK_CLOCK:
4240 /*
4241 * If the user instantiates this as a per-cpu event,
4242 * use the cpu_clock event instead.
4243 */
4244 if (event->ctx->task)
4245 pmu = &perf_ops_task_clock;
4246 else
4247 pmu = &perf_ops_cpu_clock;
4248
4249 break;
4250 case PERF_COUNT_SW_PAGE_FAULTS:
4251 case PERF_COUNT_SW_PAGE_FAULTS_MIN:
4252 case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
4253 case PERF_COUNT_SW_CONTEXT_SWITCHES:
4254 case PERF_COUNT_SW_CPU_MIGRATIONS:
4255 if (!event->parent) {
4256 atomic_inc(&perf_swevent_enabled[event_id]);
4257 event->destroy = sw_perf_event_destroy;
4258 }
4259 pmu = &perf_ops_generic;
4260 break;
4261 }
4262
4263 return pmu;
4264}
4265
4266/*
4267 * Allocate and initialize a event structure
4268 */
4269static struct perf_event *
4270perf_event_alloc(struct perf_event_attr *attr,
4271 int cpu,
4272 struct perf_event_context *ctx,
4273 struct perf_event *group_leader,
4274 struct perf_event *parent_event,
4275 gfp_t gfpflags)
4276{
4277 const struct pmu *pmu;
4278 struct perf_event *event;
4279 struct hw_perf_event *hwc;
4280 long err;
4281
4282 event = kzalloc(sizeof(*event), gfpflags);
4283 if (!event)
4284 return ERR_PTR(-ENOMEM);
4285
4286 /*
4287 * Single events are their own group leaders, with an
4288 * empty sibling list:
4289 */
4290 if (!group_leader)
4291 group_leader = event;
4292
4293 mutex_init(&event->child_mutex);
4294 INIT_LIST_HEAD(&event->child_list);
4295
4296 INIT_LIST_HEAD(&event->group_entry);
4297 INIT_LIST_HEAD(&event->event_entry);
4298 INIT_LIST_HEAD(&event->sibling_list);
4299 init_waitqueue_head(&event->waitq);
4300
4301 mutex_init(&event->mmap_mutex);
4302
4303 event->cpu = cpu;
4304 event->attr = *attr;
4305 event->group_leader = group_leader;
4306 event->pmu = NULL;
4307 event->ctx = ctx;
4308 event->oncpu = -1;
4309
4310 event->parent = parent_event;
4311
4312 event->ns = get_pid_ns(current->nsproxy->pid_ns);
4313 event->id = atomic64_inc_return(&perf_event_id);
4314
4315 event->state = PERF_EVENT_STATE_INACTIVE;
4316
4317 if (attr->disabled)
4318 event->state = PERF_EVENT_STATE_OFF;
4319
4320 pmu = NULL;
4321
4322 hwc = &event->hw;
4323 hwc->sample_period = attr->sample_period;
4324 if (attr->freq && attr->sample_freq)
4325 hwc->sample_period = 1;
4326 hwc->last_period = hwc->sample_period;
4327
4328 atomic64_set(&hwc->period_left, hwc->sample_period);
4329
4330 /*
4331 * we currently do not support PERF_FORMAT_GROUP on inherited events
4332 */
4333 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
4334 goto done;
4335
4336 switch (attr->type) {
4337 case PERF_TYPE_RAW:
4338 case PERF_TYPE_HARDWARE:
4339 case PERF_TYPE_HW_CACHE:
4340 pmu = hw_perf_event_init(event);
4341 break;
4342
4343 case PERF_TYPE_SOFTWARE:
4344 pmu = sw_perf_event_init(event);
4345 break;
4346
4347 case PERF_TYPE_TRACEPOINT:
4348 pmu = tp_perf_event_init(event);
4349 break;
4350
4351 default:
4352 break;
4353 }
4354done:
4355 err = 0;
4356 if (!pmu)
4357 err = -EINVAL;
4358 else if (IS_ERR(pmu))
4359 err = PTR_ERR(pmu);
4360
4361 if (err) {
4362 if (event->ns)
4363 put_pid_ns(event->ns);
4364 kfree(event);
4365 return ERR_PTR(err);
4366 }
4367
4368 event->pmu = pmu;
4369
4370 if (!event->parent) {
4371 atomic_inc(&nr_events);
4372 if (event->attr.mmap)
4373 atomic_inc(&nr_mmap_events);
4374 if (event->attr.comm)
4375 atomic_inc(&nr_comm_events);
4376 if (event->attr.task)
4377 atomic_inc(&nr_task_events);
4378 }
4379
4380 return event;
4381}
4382
4383static int perf_copy_attr(struct perf_event_attr __user *uattr,
4384 struct perf_event_attr *attr)
4385{
4386 u32 size;
4387 int ret;
4388
4389 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
4390 return -EFAULT;
4391
4392 /*
4393 * zero the full structure, so that a short copy will be nice.
4394 */
4395 memset(attr, 0, sizeof(*attr));
4396
4397 ret = get_user(size, &uattr->size);
4398 if (ret)
4399 return ret;
4400
4401 if (size > PAGE_SIZE) /* silly large */
4402 goto err_size;
4403
4404 if (!size) /* abi compat */
4405 size = PERF_ATTR_SIZE_VER0;
4406
4407 if (size < PERF_ATTR_SIZE_VER0)
4408 goto err_size;
4409
4410 /*
4411 * If we're handed a bigger struct than we know of,
4412 * ensure all the unknown bits are 0 - i.e. new
4413 * user-space does not rely on any kernel feature
4414 * extensions we dont know about yet.
4415 */
4416 if (size > sizeof(*attr)) {
4417 unsigned char __user *addr;
4418 unsigned char __user *end;
4419 unsigned char val;
4420
4421 addr = (void __user *)uattr + sizeof(*attr);
4422 end = (void __user *)uattr + size;
4423
4424 for (; addr < end; addr++) {
4425 ret = get_user(val, addr);
4426 if (ret)
4427 return ret;
4428 if (val)
4429 goto err_size;
4430 }
4431 size = sizeof(*attr);
4432 }
4433
4434 ret = copy_from_user(attr, uattr, size);
4435 if (ret)
4436 return -EFAULT;
4437
4438 /*
4439 * If the type exists, the corresponding creation will verify
4440 * the attr->config.
4441 */
4442 if (attr->type >= PERF_TYPE_MAX)
4443 return -EINVAL;
4444
4445 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
4446 return -EINVAL;
4447
4448 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
4449 return -EINVAL;
4450
4451 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
4452 return -EINVAL;
4453
4454out:
4455 return ret;
4456
4457err_size:
4458 put_user(sizeof(*attr), &uattr->size);
4459 ret = -E2BIG;
4460 goto out;
4461}
4462
4463static int perf_event_set_output(struct perf_event *event, int output_fd)
4464{
4465 struct perf_event *output_event = NULL;
4466 struct file *output_file = NULL;
4467 struct perf_event *old_output;
4468 int fput_needed = 0;
4469 int ret = -EINVAL;
4470
4471 if (!output_fd)
4472 goto set;
4473
4474 output_file = fget_light(output_fd, &fput_needed);
4475 if (!output_file)
4476 return -EBADF;
4477
4478 if (output_file->f_op != &perf_fops)
4479 goto out;
4480
4481 output_event = output_file->private_data;
4482
4483 /* Don't chain output fds */
4484 if (output_event->output)
4485 goto out;
4486
4487 /* Don't set an output fd when we already have an output channel */
4488 if (event->data)
4489 goto out;
4490
4491 atomic_long_inc(&output_file->f_count);
4492
4493set:
4494 mutex_lock(&event->mmap_mutex);
4495 old_output = event->output;
4496 rcu_assign_pointer(event->output, output_event);
4497 mutex_unlock(&event->mmap_mutex);
4498
4499 if (old_output) {
4500 /*
4501 * we need to make sure no existing perf_output_*()
4502 * is still referencing this event.
4503 */
4504 synchronize_rcu();
4505 fput(old_output->filp);
4506 }
4507
4508 ret = 0;
4509out:
4510 fput_light(output_file, fput_needed);
4511 return ret;
4512}
4513
4514/**
4515 * sys_perf_event_open - open a performance event, associate it to a task/cpu
4516 *
4517 * @attr_uptr: event_id type attributes for monitoring/sampling
4518 * @pid: target pid
4519 * @cpu: target cpu
4520 * @group_fd: group leader event fd
4521 */
4522SYSCALL_DEFINE5(perf_event_open,
4523 struct perf_event_attr __user *, attr_uptr,
4524 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
4525{
4526 struct perf_event *event, *group_leader;
4527 struct perf_event_attr attr;
4528 struct perf_event_context *ctx;
4529 struct file *event_file = NULL;
4530 struct file *group_file = NULL;
4531 int fput_needed = 0;
4532 int fput_needed2 = 0;
4533 int err;
4534
4535 /* for future expandability... */
4536 if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT))
4537 return -EINVAL;
4538
4539 err = perf_copy_attr(attr_uptr, &attr);
4540 if (err)
4541 return err;
4542
4543 if (!attr.exclude_kernel) {
4544 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
4545 return -EACCES;
4546 }
4547
4548 if (attr.freq) {
4549 if (attr.sample_freq > sysctl_perf_event_sample_rate)
4550 return -EINVAL;
4551 }
4552
4553 /*
4554 * Get the target context (task or percpu):
4555 */
4556 ctx = find_get_context(pid, cpu);
4557 if (IS_ERR(ctx))
4558 return PTR_ERR(ctx);
4559
4560 /*
4561 * Look up the group leader (we will attach this event to it):
4562 */
4563 group_leader = NULL;
4564 if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) {
4565 err = -EINVAL;
4566 group_file = fget_light(group_fd, &fput_needed);
4567 if (!group_file)
4568 goto err_put_context;
4569 if (group_file->f_op != &perf_fops)
4570 goto err_put_context;
4571
4572 group_leader = group_file->private_data;
4573 /*
4574 * Do not allow a recursive hierarchy (this new sibling
4575 * becoming part of another group-sibling):
4576 */
4577 if (group_leader->group_leader != group_leader)
4578 goto err_put_context;
4579 /*
4580 * Do not allow to attach to a group in a different
4581 * task or CPU context:
4582 */
4583 if (group_leader->ctx != ctx)
4584 goto err_put_context;
4585 /*
4586 * Only a group leader can be exclusive or pinned
4587 */
4588 if (attr.exclusive || attr.pinned)
4589 goto err_put_context;
4590 }
4591
4592 event = perf_event_alloc(&attr, cpu, ctx, group_leader,
4593 NULL, GFP_KERNEL);
4594 err = PTR_ERR(event);
4595 if (IS_ERR(event))
4596 goto err_put_context;
4597
4598 err = anon_inode_getfd("[perf_event]", &perf_fops, event, 0);
4599 if (err < 0)
4600 goto err_free_put_context;
4601
4602 event_file = fget_light(err, &fput_needed2);
4603 if (!event_file)
4604 goto err_free_put_context;
4605
4606 if (flags & PERF_FLAG_FD_OUTPUT) {
4607 err = perf_event_set_output(event, group_fd);
4608 if (err)
4609 goto err_fput_free_put_context;
4610 }
4611
4612 event->filp = event_file;
4613 WARN_ON_ONCE(ctx->parent_ctx);
4614 mutex_lock(&ctx->mutex);
4615 perf_install_in_context(ctx, event, cpu);
4616 ++ctx->generation;
4617 mutex_unlock(&ctx->mutex);
4618
4619 event->owner = current;
4620 get_task_struct(current);
4621 mutex_lock(&current->perf_event_mutex);
4622 list_add_tail(&event->owner_entry, &current->perf_event_list);
4623 mutex_unlock(&current->perf_event_mutex);
4624
4625err_fput_free_put_context:
4626 fput_light(event_file, fput_needed2);
4627
4628err_free_put_context:
4629 if (err < 0)
4630 kfree(event);
4631
4632err_put_context:
4633 if (err < 0)
4634 put_ctx(ctx);
4635
4636 fput_light(group_file, fput_needed);
4637
4638 return err;
4639}
4640
4641/*
4642 * inherit a event from parent task to child task:
4643 */
4644static struct perf_event *
4645inherit_event(struct perf_event *parent_event,
4646 struct task_struct *parent,
4647 struct perf_event_context *parent_ctx,
4648 struct task_struct *child,
4649 struct perf_event *group_leader,
4650 struct perf_event_context *child_ctx)
4651{
4652 struct perf_event *child_event;
4653
4654 /*
4655 * Instead of creating recursive hierarchies of events,
4656 * we link inherited events back to the original parent,
4657 * which has a filp for sure, which we use as the reference
4658 * count:
4659 */
4660 if (parent_event->parent)
4661 parent_event = parent_event->parent;
4662
4663 child_event = perf_event_alloc(&parent_event->attr,
4664 parent_event->cpu, child_ctx,
4665 group_leader, parent_event,
4666 GFP_KERNEL);
4667 if (IS_ERR(child_event))
4668 return child_event;
4669 get_ctx(child_ctx);
4670
4671 /*
4672 * Make the child state follow the state of the parent event,
4673 * not its attr.disabled bit. We hold the parent's mutex,
4674 * so we won't race with perf_event_{en, dis}able_family.
4675 */
4676 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
4677 child_event->state = PERF_EVENT_STATE_INACTIVE;
4678 else
4679 child_event->state = PERF_EVENT_STATE_OFF;
4680
4681 if (parent_event->attr.freq)
4682 child_event->hw.sample_period = parent_event->hw.sample_period;
4683
4684 /*
4685 * Link it up in the child's context:
4686 */
4687 add_event_to_ctx(child_event, child_ctx);
4688
4689 /*
4690 * Get a reference to the parent filp - we will fput it
4691 * when the child event exits. This is safe to do because
4692 * we are in the parent and we know that the filp still
4693 * exists and has a nonzero count:
4694 */
4695 atomic_long_inc(&parent_event->filp->f_count);
4696
4697 /*
4698 * Link this into the parent event's child list
4699 */
4700 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
4701 mutex_lock(&parent_event->child_mutex);
4702 list_add_tail(&child_event->child_list, &parent_event->child_list);
4703 mutex_unlock(&parent_event->child_mutex);
4704
4705 return child_event;
4706}
4707
4708static int inherit_group(struct perf_event *parent_event,
4709 struct task_struct *parent,
4710 struct perf_event_context *parent_ctx,
4711 struct task_struct *child,
4712 struct perf_event_context *child_ctx)
4713{
4714 struct perf_event *leader;
4715 struct perf_event *sub;
4716 struct perf_event *child_ctr;
4717
4718 leader = inherit_event(parent_event, parent, parent_ctx,
4719 child, NULL, child_ctx);
4720 if (IS_ERR(leader))
4721 return PTR_ERR(leader);
4722 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
4723 child_ctr = inherit_event(sub, parent, parent_ctx,
4724 child, leader, child_ctx);
4725 if (IS_ERR(child_ctr))
4726 return PTR_ERR(child_ctr);
4727 }
4728 return 0;
4729}
4730
4731static void sync_child_event(struct perf_event *child_event,
4732 struct task_struct *child)
4733{
4734 struct perf_event *parent_event = child_event->parent;
4735 u64 child_val;
4736
4737 if (child_event->attr.inherit_stat)
4738 perf_event_read_event(child_event, child);
4739
4740 child_val = atomic64_read(&child_event->count);
4741
4742 /*
4743 * Add back the child's count to the parent's count:
4744 */
4745 atomic64_add(child_val, &parent_event->count);
4746 atomic64_add(child_event->total_time_enabled,
4747 &parent_event->child_total_time_enabled);
4748 atomic64_add(child_event->total_time_running,
4749 &parent_event->child_total_time_running);
4750
4751 /*
4752 * Remove this event from the parent's list
4753 */
4754 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
4755 mutex_lock(&parent_event->child_mutex);
4756 list_del_init(&child_event->child_list);
4757 mutex_unlock(&parent_event->child_mutex);
4758
4759 /*
4760 * Release the parent event, if this was the last
4761 * reference to it.
4762 */
4763 fput(parent_event->filp);
4764}
4765
4766static void
4767__perf_event_exit_task(struct perf_event *child_event,
4768 struct perf_event_context *child_ctx,
4769 struct task_struct *child)
4770{
4771 struct perf_event *parent_event;
4772
4773 update_event_times(child_event);
4774 perf_event_remove_from_context(child_event);
4775
4776 parent_event = child_event->parent;
4777 /*
4778 * It can happen that parent exits first, and has events
4779 * that are still around due to the child reference. These
4780 * events need to be zapped - but otherwise linger.
4781 */
4782 if (parent_event) {
4783 sync_child_event(child_event, child);
4784 free_event(child_event);
4785 }
4786}
4787
4788/*
4789 * When a child task exits, feed back event values to parent events.
4790 */
4791void perf_event_exit_task(struct task_struct *child)
4792{
4793 struct perf_event *child_event, *tmp;
4794 struct perf_event_context *child_ctx;
4795 unsigned long flags;
4796
4797 if (likely(!child->perf_event_ctxp)) {
4798 perf_event_task(child, NULL, 0);
4799 return;
4800 }
4801
4802 local_irq_save(flags);
4803 /*
4804 * We can't reschedule here because interrupts are disabled,
4805 * and either child is current or it is a task that can't be
4806 * scheduled, so we are now safe from rescheduling changing
4807 * our context.
4808 */
4809 child_ctx = child->perf_event_ctxp;
4810 __perf_event_task_sched_out(child_ctx);
4811
4812 /*
4813 * Take the context lock here so that if find_get_context is
4814 * reading child->perf_event_ctxp, we wait until it has
4815 * incremented the context's refcount before we do put_ctx below.
4816 */
4817 spin_lock(&child_ctx->lock);
4818 child->perf_event_ctxp = NULL;
4819 /*
4820 * If this context is a clone; unclone it so it can't get
4821 * swapped to another process while we're removing all
4822 * the events from it.
4823 */
4824 unclone_ctx(child_ctx);
4825 spin_unlock_irqrestore(&child_ctx->lock, flags);
4826
4827 /*
4828 * Report the task dead after unscheduling the events so that we
4829 * won't get any samples after PERF_RECORD_EXIT. We can however still
4830 * get a few PERF_RECORD_READ events.
4831 */
4832 perf_event_task(child, child_ctx, 0);
4833
4834 /*
4835 * We can recurse on the same lock type through:
4836 *
4837 * __perf_event_exit_task()
4838 * sync_child_event()
4839 * fput(parent_event->filp)
4840 * perf_release()
4841 * mutex_lock(&ctx->mutex)
4842 *
4843 * But since its the parent context it won't be the same instance.
4844 */
4845 mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING);
4846
4847again:
4848 list_for_each_entry_safe(child_event, tmp, &child_ctx->group_list,
4849 group_entry)
4850 __perf_event_exit_task(child_event, child_ctx, child);
4851
4852 /*
4853 * If the last event was a group event, it will have appended all
4854 * its siblings to the list, but we obtained 'tmp' before that which
4855 * will still point to the list head terminating the iteration.
4856 */
4857 if (!list_empty(&child_ctx->group_list))
4858 goto again;
4859
4860 mutex_unlock(&child_ctx->mutex);
4861
4862 put_ctx(child_ctx);
4863}
4864
4865/*
4866 * free an unexposed, unused context as created by inheritance by
4867 * init_task below, used by fork() in case of fail.
4868 */
4869void perf_event_free_task(struct task_struct *task)
4870{
4871 struct perf_event_context *ctx = task->perf_event_ctxp;
4872 struct perf_event *event, *tmp;
4873
4874 if (!ctx)
4875 return;
4876
4877 mutex_lock(&ctx->mutex);
4878again:
4879 list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry) {
4880 struct perf_event *parent = event->parent;
4881
4882 if (WARN_ON_ONCE(!parent))
4883 continue;
4884
4885 mutex_lock(&parent->child_mutex);
4886 list_del_init(&event->child_list);
4887 mutex_unlock(&parent->child_mutex);
4888
4889 fput(parent->filp);
4890
4891 list_del_event(event, ctx);
4892 free_event(event);
4893 }
4894
4895 if (!list_empty(&ctx->group_list))
4896 goto again;
4897
4898 mutex_unlock(&ctx->mutex);
4899
4900 put_ctx(ctx);
4901}
4902
4903/*
4904 * Initialize the perf_event context in task_struct
4905 */
4906int perf_event_init_task(struct task_struct *child)
4907{
4908 struct perf_event_context *child_ctx, *parent_ctx;
4909 struct perf_event_context *cloned_ctx;
4910 struct perf_event *event;
4911 struct task_struct *parent = current;
4912 int inherited_all = 1;
4913 int ret = 0;
4914
4915 child->perf_event_ctxp = NULL;
4916
4917 mutex_init(&child->perf_event_mutex);
4918 INIT_LIST_HEAD(&child->perf_event_list);
4919
4920 if (likely(!parent->perf_event_ctxp))
4921 return 0;
4922
4923 /*
4924 * This is executed from the parent task context, so inherit
4925 * events that have been marked for cloning.
4926 * First allocate and initialize a context for the child.
4927 */
4928
4929 child_ctx = kmalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4930 if (!child_ctx)
4931 return -ENOMEM;
4932
4933 __perf_event_init_context(child_ctx, child);
4934 child->perf_event_ctxp = child_ctx;
4935 get_task_struct(child);
4936
4937 /*
4938 * If the parent's context is a clone, pin it so it won't get
4939 * swapped under us.
4940 */
4941 parent_ctx = perf_pin_task_context(parent);
4942
4943 /*
4944 * No need to check if parent_ctx != NULL here; since we saw
4945 * it non-NULL earlier, the only reason for it to become NULL
4946 * is if we exit, and since we're currently in the middle of
4947 * a fork we can't be exiting at the same time.
4948 */
4949
4950 /*
4951 * Lock the parent list. No need to lock the child - not PID
4952 * hashed yet and not running, so nobody can access it.
4953 */
4954 mutex_lock(&parent_ctx->mutex);
4955
4956 /*
4957 * We dont have to disable NMIs - we are only looking at
4958 * the list, not manipulating it:
4959 */
4960 list_for_each_entry(event, &parent_ctx->group_list, group_entry) {
4961
4962 if (!event->attr.inherit) {
4963 inherited_all = 0;
4964 continue;
4965 }
4966
4967 ret = inherit_group(event, parent, parent_ctx,
4968 child, child_ctx);
4969 if (ret) {
4970 inherited_all = 0;
4971 break;
4972 }
4973 }
4974
4975 if (inherited_all) {
4976 /*
4977 * Mark the child context as a clone of the parent
4978 * context, or of whatever the parent is a clone of.
4979 * Note that if the parent is a clone, it could get
4980 * uncloned at any point, but that doesn't matter
4981 * because the list of events and the generation
4982 * count can't have changed since we took the mutex.
4983 */
4984 cloned_ctx = rcu_dereference(parent_ctx->parent_ctx);
4985 if (cloned_ctx) {
4986 child_ctx->parent_ctx = cloned_ctx;
4987 child_ctx->parent_gen = parent_ctx->parent_gen;
4988 } else {
4989 child_ctx->parent_ctx = parent_ctx;
4990 child_ctx->parent_gen = parent_ctx->generation;
4991 }
4992 get_ctx(child_ctx->parent_ctx);
4993 }
4994
4995 mutex_unlock(&parent_ctx->mutex);
4996
4997 perf_unpin_context(parent_ctx);
4998
4999 return ret;
5000}
5001
5002static void __cpuinit perf_event_init_cpu(int cpu)
5003{
5004 struct perf_cpu_context *cpuctx;
5005
5006 cpuctx = &per_cpu(perf_cpu_context, cpu);
5007 __perf_event_init_context(&cpuctx->ctx, NULL);
5008
5009 spin_lock(&perf_resource_lock);
5010 cpuctx->max_pertask = perf_max_events - perf_reserved_percpu;
5011 spin_unlock(&perf_resource_lock);
5012
5013 hw_perf_event_setup(cpu);
5014}
5015
5016#ifdef CONFIG_HOTPLUG_CPU
5017static void __perf_event_exit_cpu(void *info)
5018{
5019 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
5020 struct perf_event_context *ctx = &cpuctx->ctx;
5021 struct perf_event *event, *tmp;
5022
5023 list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry)
5024 __perf_event_remove_from_context(event);
5025}
5026static void perf_event_exit_cpu(int cpu)
5027{
5028 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
5029 struct perf_event_context *ctx = &cpuctx->ctx;
5030
5031 mutex_lock(&ctx->mutex);
5032 smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1);
5033 mutex_unlock(&ctx->mutex);
5034}
5035#else
5036static inline void perf_event_exit_cpu(int cpu) { }
5037#endif
5038
5039static int __cpuinit
5040perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
5041{
5042 unsigned int cpu = (long)hcpu;
5043
5044 switch (action) {
5045
5046 case CPU_UP_PREPARE:
5047 case CPU_UP_PREPARE_FROZEN:
5048 perf_event_init_cpu(cpu);
5049 break;
5050
5051 case CPU_ONLINE:
5052 case CPU_ONLINE_FROZEN:
5053 hw_perf_event_setup_online(cpu);
5054 break;
5055
5056 case CPU_DOWN_PREPARE:
5057 case CPU_DOWN_PREPARE_FROZEN:
5058 perf_event_exit_cpu(cpu);
5059 break;
5060
5061 default:
5062 break;
5063 }
5064
5065 return NOTIFY_OK;
5066}
5067
5068/*
5069 * This has to have a higher priority than migration_notifier in sched.c.
5070 */
5071static struct notifier_block __cpuinitdata perf_cpu_nb = {
5072 .notifier_call = perf_cpu_notify,
5073 .priority = 20,
5074};
5075
5076void __init perf_event_init(void)
5077{
5078 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
5079 (void *)(long)smp_processor_id());
5080 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
5081 (void *)(long)smp_processor_id());
5082 register_cpu_notifier(&perf_cpu_nb);
5083}
5084
5085static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
5086{
5087 return sprintf(buf, "%d\n", perf_reserved_percpu);
5088}
5089
5090static ssize_t
5091perf_set_reserve_percpu(struct sysdev_class *class,
5092 const char *buf,
5093 size_t count)
5094{
5095 struct perf_cpu_context *cpuctx;
5096 unsigned long val;
5097 int err, cpu, mpt;
5098
5099 err = strict_strtoul(buf, 10, &val);
5100 if (err)
5101 return err;
5102 if (val > perf_max_events)
5103 return -EINVAL;
5104
5105 spin_lock(&perf_resource_lock);
5106 perf_reserved_percpu = val;
5107 for_each_online_cpu(cpu) {
5108 cpuctx = &per_cpu(perf_cpu_context, cpu);
5109 spin_lock_irq(&cpuctx->ctx.lock);
5110 mpt = min(perf_max_events - cpuctx->ctx.nr_events,
5111 perf_max_events - perf_reserved_percpu);
5112 cpuctx->max_pertask = mpt;
5113 spin_unlock_irq(&cpuctx->ctx.lock);
5114 }
5115 spin_unlock(&perf_resource_lock);
5116
5117 return count;
5118}
5119
5120static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
5121{
5122 return sprintf(buf, "%d\n", perf_overcommit);
5123}
5124
5125static ssize_t
5126perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
5127{
5128 unsigned long val;
5129 int err;
5130
5131 err = strict_strtoul(buf, 10, &val);
5132 if (err)
5133 return err;
5134 if (val > 1)
5135 return -EINVAL;
5136
5137 spin_lock(&perf_resource_lock);
5138 perf_overcommit = val;
5139 spin_unlock(&perf_resource_lock);
5140
5141 return count;
5142}
5143
5144static SYSDEV_CLASS_ATTR(
5145 reserve_percpu,
5146 0644,
5147 perf_show_reserve_percpu,
5148 perf_set_reserve_percpu
5149 );
5150
5151static SYSDEV_CLASS_ATTR(
5152 overcommit,
5153 0644,
5154 perf_show_overcommit,
5155 perf_set_overcommit
5156 );
5157
5158static struct attribute *perfclass_attrs[] = {
5159 &attr_reserve_percpu.attr,
5160 &attr_overcommit.attr,
5161 NULL
5162};
5163
5164static struct attribute_group perfclass_attr_group = {
5165 .attrs = perfclass_attrs,
5166 .name = "perf_events",
5167};
5168
5169static int __init perf_event_sysfs_init(void)
5170{
5171 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
5172 &perfclass_attr_group);
5173}
5174device_initcall(perf_event_sysfs_init);
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-12 00:51:28 -0500