aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/perf_counter.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/perf_counter.c')
-rw-r--r--kernel/perf_counter.c3526
1 files changed, 3526 insertions, 0 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
new file mode 100644
index 000000000000..59a926d04baf
--- /dev/null
+++ b/kernel/perf_counter.c
@@ -0,0 +1,3526 @@
1/*
2 * Performance counter 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/ptrace.h>
20#include <linux/percpu.h>
21#include <linux/vmstat.h>
22#include <linux/hardirq.h>
23#include <linux/rculist.h>
24#include <linux/uaccess.h>
25#include <linux/syscalls.h>
26#include <linux/anon_inodes.h>
27#include <linux/kernel_stat.h>
28#include <linux/perf_counter.h>
29#include <linux/dcache.h>
30
31#include <asm/irq_regs.h>
32
33/*
34 * Each CPU has a list of per CPU counters:
35 */
36DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
37
38int perf_max_counters __read_mostly = 1;
39static int perf_reserved_percpu __read_mostly;
40static int perf_overcommit __read_mostly = 1;
41
42static atomic_t nr_counters __read_mostly;
43static atomic_t nr_mmap_tracking __read_mostly;
44static atomic_t nr_munmap_tracking __read_mostly;
45static atomic_t nr_comm_tracking __read_mostly;
46
47int sysctl_perf_counter_priv __read_mostly; /* do we need to be privileged */
48int sysctl_perf_counter_mlock __read_mostly = 512; /* 'free' kb per user */
49
50/*
51 * Lock for (sysadmin-configurable) counter reservations:
52 */
53static DEFINE_SPINLOCK(perf_resource_lock);
54
55/*
56 * Architecture provided APIs - weak aliases:
57 */
58extern __weak const struct pmu *hw_perf_counter_init(struct perf_counter *counter)
59{
60 return NULL;
61}
62
63void __weak hw_perf_disable(void) { barrier(); }
64void __weak hw_perf_enable(void) { barrier(); }
65
66void __weak hw_perf_counter_setup(int cpu) { barrier(); }
67int __weak hw_perf_group_sched_in(struct perf_counter *group_leader,
68 struct perf_cpu_context *cpuctx,
69 struct perf_counter_context *ctx, int cpu)
70{
71 return 0;
72}
73
74void __weak perf_counter_print_debug(void) { }
75
76static DEFINE_PER_CPU(int, disable_count);
77
78void __perf_disable(void)
79{
80 __get_cpu_var(disable_count)++;
81}
82
83bool __perf_enable(void)
84{
85 return !--__get_cpu_var(disable_count);
86}
87
88void perf_disable(void)
89{
90 __perf_disable();
91 hw_perf_disable();
92}
93
94void perf_enable(void)
95{
96 if (__perf_enable())
97 hw_perf_enable();
98}
99
100static void
101list_add_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
102{
103 struct perf_counter *group_leader = counter->group_leader;
104
105 /*
106 * Depending on whether it is a standalone or sibling counter,
107 * add it straight to the context's counter list, or to the group
108 * leader's sibling list:
109 */
110 if (group_leader == counter)
111 list_add_tail(&counter->list_entry, &ctx->counter_list);
112 else {
113 list_add_tail(&counter->list_entry, &group_leader->sibling_list);
114 group_leader->nr_siblings++;
115 }
116
117 list_add_rcu(&counter->event_entry, &ctx->event_list);
118 ctx->nr_counters++;
119}
120
121static void
122list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx)
123{
124 struct perf_counter *sibling, *tmp;
125
126 ctx->nr_counters--;
127
128 list_del_init(&counter->list_entry);
129 list_del_rcu(&counter->event_entry);
130
131 if (counter->group_leader != counter)
132 counter->group_leader->nr_siblings--;
133
134 /*
135 * If this was a group counter with sibling counters then
136 * upgrade the siblings to singleton counters by adding them
137 * to the context list directly:
138 */
139 list_for_each_entry_safe(sibling, tmp,
140 &counter->sibling_list, list_entry) {
141
142 list_move_tail(&sibling->list_entry, &ctx->counter_list);
143 sibling->group_leader = sibling;
144 }
145}
146
147static void
148counter_sched_out(struct perf_counter *counter,
149 struct perf_cpu_context *cpuctx,
150 struct perf_counter_context *ctx)
151{
152 if (counter->state != PERF_COUNTER_STATE_ACTIVE)
153 return;
154
155 counter->state = PERF_COUNTER_STATE_INACTIVE;
156 counter->tstamp_stopped = ctx->time;
157 counter->pmu->disable(counter);
158 counter->oncpu = -1;
159
160 if (!is_software_counter(counter))
161 cpuctx->active_oncpu--;
162 ctx->nr_active--;
163 if (counter->hw_event.exclusive || !cpuctx->active_oncpu)
164 cpuctx->exclusive = 0;
165}
166
167static void
168group_sched_out(struct perf_counter *group_counter,
169 struct perf_cpu_context *cpuctx,
170 struct perf_counter_context *ctx)
171{
172 struct perf_counter *counter;
173
174 if (group_counter->state != PERF_COUNTER_STATE_ACTIVE)
175 return;
176
177 counter_sched_out(group_counter, cpuctx, ctx);
178
179 /*
180 * Schedule out siblings (if any):
181 */
182 list_for_each_entry(counter, &group_counter->sibling_list, list_entry)
183 counter_sched_out(counter, cpuctx, ctx);
184
185 if (group_counter->hw_event.exclusive)
186 cpuctx->exclusive = 0;
187}
188
189/*
190 * Cross CPU call to remove a performance counter
191 *
192 * We disable the counter on the hardware level first. After that we
193 * remove it from the context list.
194 */
195static void __perf_counter_remove_from_context(void *info)
196{
197 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
198 struct perf_counter *counter = info;
199 struct perf_counter_context *ctx = counter->ctx;
200 unsigned long flags;
201
202 /*
203 * If this is a task context, we need to check whether it is
204 * the current task context of this cpu. If not it has been
205 * scheduled out before the smp call arrived.
206 */
207 if (ctx->task && cpuctx->task_ctx != ctx)
208 return;
209
210 spin_lock_irqsave(&ctx->lock, flags);
211
212 counter_sched_out(counter, cpuctx, ctx);
213
214 counter->task = NULL;
215
216 /*
217 * Protect the list operation against NMI by disabling the
218 * counters on a global level. NOP for non NMI based counters.
219 */
220 perf_disable();
221 list_del_counter(counter, ctx);
222 perf_enable();
223
224 if (!ctx->task) {
225 /*
226 * Allow more per task counters with respect to the
227 * reservation:
228 */
229 cpuctx->max_pertask =
230 min(perf_max_counters - ctx->nr_counters,
231 perf_max_counters - perf_reserved_percpu);
232 }
233
234 spin_unlock_irqrestore(&ctx->lock, flags);
235}
236
237
238/*
239 * Remove the counter from a task's (or a CPU's) list of counters.
240 *
241 * Must be called with counter->mutex and ctx->mutex held.
242 *
243 * CPU counters are removed with a smp call. For task counters we only
244 * call when the task is on a CPU.
245 */
246static void perf_counter_remove_from_context(struct perf_counter *counter)
247{
248 struct perf_counter_context *ctx = counter->ctx;
249 struct task_struct *task = ctx->task;
250
251 if (!task) {
252 /*
253 * Per cpu counters are removed via an smp call and
254 * the removal is always sucessful.
255 */
256 smp_call_function_single(counter->cpu,
257 __perf_counter_remove_from_context,
258 counter, 1);
259 return;
260 }
261
262retry:
263 task_oncpu_function_call(task, __perf_counter_remove_from_context,
264 counter);
265
266 spin_lock_irq(&ctx->lock);
267 /*
268 * If the context is active we need to retry the smp call.
269 */
270 if (ctx->nr_active && !list_empty(&counter->list_entry)) {
271 spin_unlock_irq(&ctx->lock);
272 goto retry;
273 }
274
275 /*
276 * The lock prevents that this context is scheduled in so we
277 * can remove the counter safely, if the call above did not
278 * succeed.
279 */
280 if (!list_empty(&counter->list_entry)) {
281 list_del_counter(counter, ctx);
282 counter->task = NULL;
283 }
284 spin_unlock_irq(&ctx->lock);
285}
286
287static inline u64 perf_clock(void)
288{
289 return cpu_clock(smp_processor_id());
290}
291
292/*
293 * Update the record of the current time in a context.
294 */
295static void update_context_time(struct perf_counter_context *ctx)
296{
297 u64 now = perf_clock();
298
299 ctx->time += now - ctx->timestamp;
300 ctx->timestamp = now;
301}
302
303/*
304 * Update the total_time_enabled and total_time_running fields for a counter.
305 */
306static void update_counter_times(struct perf_counter *counter)
307{
308 struct perf_counter_context *ctx = counter->ctx;
309 u64 run_end;
310
311 if (counter->state < PERF_COUNTER_STATE_INACTIVE)
312 return;
313
314 counter->total_time_enabled = ctx->time - counter->tstamp_enabled;
315
316 if (counter->state == PERF_COUNTER_STATE_INACTIVE)
317 run_end = counter->tstamp_stopped;
318 else
319 run_end = ctx->time;
320
321 counter->total_time_running = run_end - counter->tstamp_running;
322}
323
324/*
325 * Update total_time_enabled and total_time_running for all counters in a group.
326 */
327static void update_group_times(struct perf_counter *leader)
328{
329 struct perf_counter *counter;
330
331 update_counter_times(leader);
332 list_for_each_entry(counter, &leader->sibling_list, list_entry)
333 update_counter_times(counter);
334}
335
336/*
337 * Cross CPU call to disable a performance counter
338 */
339static void __perf_counter_disable(void *info)
340{
341 struct perf_counter *counter = info;
342 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
343 struct perf_counter_context *ctx = counter->ctx;
344 unsigned long flags;
345
346 /*
347 * If this is a per-task counter, need to check whether this
348 * counter's task is the current task on this cpu.
349 */
350 if (ctx->task && cpuctx->task_ctx != ctx)
351 return;
352
353 spin_lock_irqsave(&ctx->lock, flags);
354
355 /*
356 * If the counter is on, turn it off.
357 * If it is in error state, leave it in error state.
358 */
359 if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
360 update_context_time(ctx);
361 update_counter_times(counter);
362 if (counter == counter->group_leader)
363 group_sched_out(counter, cpuctx, ctx);
364 else
365 counter_sched_out(counter, cpuctx, ctx);
366 counter->state = PERF_COUNTER_STATE_OFF;
367 }
368
369 spin_unlock_irqrestore(&ctx->lock, flags);
370}
371
372/*
373 * Disable a counter.
374 */
375static void perf_counter_disable(struct perf_counter *counter)
376{
377 struct perf_counter_context *ctx = counter->ctx;
378 struct task_struct *task = ctx->task;
379
380 if (!task) {
381 /*
382 * Disable the counter on the cpu that it's on
383 */
384 smp_call_function_single(counter->cpu, __perf_counter_disable,
385 counter, 1);
386 return;
387 }
388
389 retry:
390 task_oncpu_function_call(task, __perf_counter_disable, counter);
391
392 spin_lock_irq(&ctx->lock);
393 /*
394 * If the counter is still active, we need to retry the cross-call.
395 */
396 if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
397 spin_unlock_irq(&ctx->lock);
398 goto retry;
399 }
400
401 /*
402 * Since we have the lock this context can't be scheduled
403 * in, so we can change the state safely.
404 */
405 if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
406 update_counter_times(counter);
407 counter->state = PERF_COUNTER_STATE_OFF;
408 }
409
410 spin_unlock_irq(&ctx->lock);
411}
412
413static int
414counter_sched_in(struct perf_counter *counter,
415 struct perf_cpu_context *cpuctx,
416 struct perf_counter_context *ctx,
417 int cpu)
418{
419 if (counter->state <= PERF_COUNTER_STATE_OFF)
420 return 0;
421
422 counter->state = PERF_COUNTER_STATE_ACTIVE;
423 counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
424 /*
425 * The new state must be visible before we turn it on in the hardware:
426 */
427 smp_wmb();
428
429 if (counter->pmu->enable(counter)) {
430 counter->state = PERF_COUNTER_STATE_INACTIVE;
431 counter->oncpu = -1;
432 return -EAGAIN;
433 }
434
435 counter->tstamp_running += ctx->time - counter->tstamp_stopped;
436
437 if (!is_software_counter(counter))
438 cpuctx->active_oncpu++;
439 ctx->nr_active++;
440
441 if (counter->hw_event.exclusive)
442 cpuctx->exclusive = 1;
443
444 return 0;
445}
446
447static int
448group_sched_in(struct perf_counter *group_counter,
449 struct perf_cpu_context *cpuctx,
450 struct perf_counter_context *ctx,
451 int cpu)
452{
453 struct perf_counter *counter, *partial_group;
454 int ret;
455
456 if (group_counter->state == PERF_COUNTER_STATE_OFF)
457 return 0;
458
459 ret = hw_perf_group_sched_in(group_counter, cpuctx, ctx, cpu);
460 if (ret)
461 return ret < 0 ? ret : 0;
462
463 group_counter->prev_state = group_counter->state;
464 if (counter_sched_in(group_counter, cpuctx, ctx, cpu))
465 return -EAGAIN;
466
467 /*
468 * Schedule in siblings as one group (if any):
469 */
470 list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
471 counter->prev_state = counter->state;
472 if (counter_sched_in(counter, cpuctx, ctx, cpu)) {
473 partial_group = counter;
474 goto group_error;
475 }
476 }
477
478 return 0;
479
480group_error:
481 /*
482 * Groups can be scheduled in as one unit only, so undo any
483 * partial group before returning:
484 */
485 list_for_each_entry(counter, &group_counter->sibling_list, list_entry) {
486 if (counter == partial_group)
487 break;
488 counter_sched_out(counter, cpuctx, ctx);
489 }
490 counter_sched_out(group_counter, cpuctx, ctx);
491
492 return -EAGAIN;
493}
494
495/*
496 * Return 1 for a group consisting entirely of software counters,
497 * 0 if the group contains any hardware counters.
498 */
499static int is_software_only_group(struct perf_counter *leader)
500{
501 struct perf_counter *counter;
502
503 if (!is_software_counter(leader))
504 return 0;
505
506 list_for_each_entry(counter, &leader->sibling_list, list_entry)
507 if (!is_software_counter(counter))
508 return 0;
509
510 return 1;
511}
512
513/*
514 * Work out whether we can put this counter group on the CPU now.
515 */
516static int group_can_go_on(struct perf_counter *counter,
517 struct perf_cpu_context *cpuctx,
518 int can_add_hw)
519{
520 /*
521 * Groups consisting entirely of software counters can always go on.
522 */
523 if (is_software_only_group(counter))
524 return 1;
525 /*
526 * If an exclusive group is already on, no other hardware
527 * counters can go on.
528 */
529 if (cpuctx->exclusive)
530 return 0;
531 /*
532 * If this group is exclusive and there are already
533 * counters on the CPU, it can't go on.
534 */
535 if (counter->hw_event.exclusive && cpuctx->active_oncpu)
536 return 0;
537 /*
538 * Otherwise, try to add it if all previous groups were able
539 * to go on.
540 */
541 return can_add_hw;
542}
543
544static void add_counter_to_ctx(struct perf_counter *counter,
545 struct perf_counter_context *ctx)
546{
547 list_add_counter(counter, ctx);
548 counter->prev_state = PERF_COUNTER_STATE_OFF;
549 counter->tstamp_enabled = ctx->time;
550 counter->tstamp_running = ctx->time;
551 counter->tstamp_stopped = ctx->time;
552}
553
554/*
555 * Cross CPU call to install and enable a performance counter
556 */
557static void __perf_install_in_context(void *info)
558{
559 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
560 struct perf_counter *counter = info;
561 struct perf_counter_context *ctx = counter->ctx;
562 struct perf_counter *leader = counter->group_leader;
563 int cpu = smp_processor_id();
564 unsigned long flags;
565 int err;
566
567 /*
568 * If this is a task context, we need to check whether it is
569 * the current task context of this cpu. If not it has been
570 * scheduled out before the smp call arrived.
571 */
572 if (ctx->task && cpuctx->task_ctx != ctx)
573 return;
574
575 spin_lock_irqsave(&ctx->lock, flags);
576 update_context_time(ctx);
577
578 /*
579 * Protect the list operation against NMI by disabling the
580 * counters on a global level. NOP for non NMI based counters.
581 */
582 perf_disable();
583
584 add_counter_to_ctx(counter, ctx);
585
586 /*
587 * Don't put the counter on if it is disabled or if
588 * it is in a group and the group isn't on.
589 */
590 if (counter->state != PERF_COUNTER_STATE_INACTIVE ||
591 (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE))
592 goto unlock;
593
594 /*
595 * An exclusive counter can't go on if there are already active
596 * hardware counters, and no hardware counter can go on if there
597 * is already an exclusive counter on.
598 */
599 if (!group_can_go_on(counter, cpuctx, 1))
600 err = -EEXIST;
601 else
602 err = counter_sched_in(counter, cpuctx, ctx, cpu);
603
604 if (err) {
605 /*
606 * This counter couldn't go on. If it is in a group
607 * then we have to pull the whole group off.
608 * If the counter group is pinned then put it in error state.
609 */
610 if (leader != counter)
611 group_sched_out(leader, cpuctx, ctx);
612 if (leader->hw_event.pinned) {
613 update_group_times(leader);
614 leader->state = PERF_COUNTER_STATE_ERROR;
615 }
616 }
617
618 if (!err && !ctx->task && cpuctx->max_pertask)
619 cpuctx->max_pertask--;
620
621 unlock:
622 perf_enable();
623
624 spin_unlock_irqrestore(&ctx->lock, flags);
625}
626
627/*
628 * Attach a performance counter to a context
629 *
630 * First we add the counter to the list with the hardware enable bit
631 * in counter->hw_config cleared.
632 *
633 * If the counter is attached to a task which is on a CPU we use a smp
634 * call to enable it in the task context. The task might have been
635 * scheduled away, but we check this in the smp call again.
636 *
637 * Must be called with ctx->mutex held.
638 */
639static void
640perf_install_in_context(struct perf_counter_context *ctx,
641 struct perf_counter *counter,
642 int cpu)
643{
644 struct task_struct *task = ctx->task;
645
646 if (!task) {
647 /*
648 * Per cpu counters are installed via an smp call and
649 * the install is always sucessful.
650 */
651 smp_call_function_single(cpu, __perf_install_in_context,
652 counter, 1);
653 return;
654 }
655
656 counter->task = task;
657retry:
658 task_oncpu_function_call(task, __perf_install_in_context,
659 counter);
660
661 spin_lock_irq(&ctx->lock);
662 /*
663 * we need to retry the smp call.
664 */
665 if (ctx->is_active && list_empty(&counter->list_entry)) {
666 spin_unlock_irq(&ctx->lock);
667 goto retry;
668 }
669
670 /*
671 * The lock prevents that this context is scheduled in so we
672 * can add the counter safely, if it the call above did not
673 * succeed.
674 */
675 if (list_empty(&counter->list_entry))
676 add_counter_to_ctx(counter, ctx);
677 spin_unlock_irq(&ctx->lock);
678}
679
680/*
681 * Cross CPU call to enable a performance counter
682 */
683static void __perf_counter_enable(void *info)
684{
685 struct perf_counter *counter = info;
686 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
687 struct perf_counter_context *ctx = counter->ctx;
688 struct perf_counter *leader = counter->group_leader;
689 unsigned long flags;
690 int err;
691
692 /*
693 * If this is a per-task counter, need to check whether this
694 * counter's task is the current task on this cpu.
695 */
696 if (ctx->task && cpuctx->task_ctx != ctx)
697 return;
698
699 spin_lock_irqsave(&ctx->lock, flags);
700 update_context_time(ctx);
701
702 counter->prev_state = counter->state;
703 if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
704 goto unlock;
705 counter->state = PERF_COUNTER_STATE_INACTIVE;
706 counter->tstamp_enabled = ctx->time - counter->total_time_enabled;
707
708 /*
709 * If the counter is in a group and isn't the group leader,
710 * then don't put it on unless the group is on.
711 */
712 if (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE)
713 goto unlock;
714
715 if (!group_can_go_on(counter, cpuctx, 1)) {
716 err = -EEXIST;
717 } else {
718 perf_disable();
719 if (counter == leader)
720 err = group_sched_in(counter, cpuctx, ctx,
721 smp_processor_id());
722 else
723 err = counter_sched_in(counter, cpuctx, ctx,
724 smp_processor_id());
725 perf_enable();
726 }
727
728 if (err) {
729 /*
730 * If this counter can't go on and it's part of a
731 * group, then the whole group has to come off.
732 */
733 if (leader != counter)
734 group_sched_out(leader, cpuctx, ctx);
735 if (leader->hw_event.pinned) {
736 update_group_times(leader);
737 leader->state = PERF_COUNTER_STATE_ERROR;
738 }
739 }
740
741 unlock:
742 spin_unlock_irqrestore(&ctx->lock, flags);
743}
744
745/*
746 * Enable a counter.
747 */
748static void perf_counter_enable(struct perf_counter *counter)
749{
750 struct perf_counter_context *ctx = counter->ctx;
751 struct task_struct *task = ctx->task;
752
753 if (!task) {
754 /*
755 * Enable the counter on the cpu that it's on
756 */
757 smp_call_function_single(counter->cpu, __perf_counter_enable,
758 counter, 1);
759 return;
760 }
761
762 spin_lock_irq(&ctx->lock);
763 if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
764 goto out;
765
766 /*
767 * If the counter is in error state, clear that first.
768 * That way, if we see the counter in error state below, we
769 * know that it has gone back into error state, as distinct
770 * from the task having been scheduled away before the
771 * cross-call arrived.
772 */
773 if (counter->state == PERF_COUNTER_STATE_ERROR)
774 counter->state = PERF_COUNTER_STATE_OFF;
775
776 retry:
777 spin_unlock_irq(&ctx->lock);
778 task_oncpu_function_call(task, __perf_counter_enable, counter);
779
780 spin_lock_irq(&ctx->lock);
781
782 /*
783 * If the context is active and the counter is still off,
784 * we need to retry the cross-call.
785 */
786 if (ctx->is_active && counter->state == PERF_COUNTER_STATE_OFF)
787 goto retry;
788
789 /*
790 * Since we have the lock this context can't be scheduled
791 * in, so we can change the state safely.
792 */
793 if (counter->state == PERF_COUNTER_STATE_OFF) {
794 counter->state = PERF_COUNTER_STATE_INACTIVE;
795 counter->tstamp_enabled =
796 ctx->time - counter->total_time_enabled;
797 }
798 out:
799 spin_unlock_irq(&ctx->lock);
800}
801
802static int perf_counter_refresh(struct perf_counter *counter, int refresh)
803{
804 /*
805 * not supported on inherited counters
806 */
807 if (counter->hw_event.inherit)
808 return -EINVAL;
809
810 atomic_add(refresh, &counter->event_limit);
811 perf_counter_enable(counter);
812
813 return 0;
814}
815
816void __perf_counter_sched_out(struct perf_counter_context *ctx,
817 struct perf_cpu_context *cpuctx)
818{
819 struct perf_counter *counter;
820
821 spin_lock(&ctx->lock);
822 ctx->is_active = 0;
823 if (likely(!ctx->nr_counters))
824 goto out;
825 update_context_time(ctx);
826
827 perf_disable();
828 if (ctx->nr_active) {
829 list_for_each_entry(counter, &ctx->counter_list, list_entry)
830 group_sched_out(counter, cpuctx, ctx);
831 }
832 perf_enable();
833 out:
834 spin_unlock(&ctx->lock);
835}
836
837/*
838 * Called from scheduler to remove the counters of the current task,
839 * with interrupts disabled.
840 *
841 * We stop each counter and update the counter value in counter->count.
842 *
843 * This does not protect us against NMI, but disable()
844 * sets the disabled bit in the control field of counter _before_
845 * accessing the counter control register. If a NMI hits, then it will
846 * not restart the counter.
847 */
848void perf_counter_task_sched_out(struct task_struct *task, int cpu)
849{
850 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
851 struct perf_counter_context *ctx = &task->perf_counter_ctx;
852 struct pt_regs *regs;
853
854 if (likely(!cpuctx->task_ctx))
855 return;
856
857 update_context_time(ctx);
858
859 regs = task_pt_regs(task);
860 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES, 1, 1, regs, 0);
861 __perf_counter_sched_out(ctx, cpuctx);
862
863 cpuctx->task_ctx = NULL;
864}
865
866static void __perf_counter_task_sched_out(struct perf_counter_context *ctx)
867{
868 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
869
870 __perf_counter_sched_out(ctx, cpuctx);
871 cpuctx->task_ctx = NULL;
872}
873
874static void perf_counter_cpu_sched_out(struct perf_cpu_context *cpuctx)
875{
876 __perf_counter_sched_out(&cpuctx->ctx, cpuctx);
877}
878
879static void
880__perf_counter_sched_in(struct perf_counter_context *ctx,
881 struct perf_cpu_context *cpuctx, int cpu)
882{
883 struct perf_counter *counter;
884 int can_add_hw = 1;
885
886 spin_lock(&ctx->lock);
887 ctx->is_active = 1;
888 if (likely(!ctx->nr_counters))
889 goto out;
890
891 ctx->timestamp = perf_clock();
892
893 perf_disable();
894
895 /*
896 * First go through the list and put on any pinned groups
897 * in order to give them the best chance of going on.
898 */
899 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
900 if (counter->state <= PERF_COUNTER_STATE_OFF ||
901 !counter->hw_event.pinned)
902 continue;
903 if (counter->cpu != -1 && counter->cpu != cpu)
904 continue;
905
906 if (group_can_go_on(counter, cpuctx, 1))
907 group_sched_in(counter, cpuctx, ctx, cpu);
908
909 /*
910 * If this pinned group hasn't been scheduled,
911 * put it in error state.
912 */
913 if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
914 update_group_times(counter);
915 counter->state = PERF_COUNTER_STATE_ERROR;
916 }
917 }
918
919 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
920 /*
921 * Ignore counters in OFF or ERROR state, and
922 * ignore pinned counters since we did them already.
923 */
924 if (counter->state <= PERF_COUNTER_STATE_OFF ||
925 counter->hw_event.pinned)
926 continue;
927
928 /*
929 * Listen to the 'cpu' scheduling filter constraint
930 * of counters:
931 */
932 if (counter->cpu != -1 && counter->cpu != cpu)
933 continue;
934
935 if (group_can_go_on(counter, cpuctx, can_add_hw)) {
936 if (group_sched_in(counter, cpuctx, ctx, cpu))
937 can_add_hw = 0;
938 }
939 }
940 perf_enable();
941 out:
942 spin_unlock(&ctx->lock);
943}
944
945/*
946 * Called from scheduler to add the counters of the current task
947 * with interrupts disabled.
948 *
949 * We restore the counter value and then enable it.
950 *
951 * This does not protect us against NMI, but enable()
952 * sets the enabled bit in the control field of counter _before_
953 * accessing the counter control register. If a NMI hits, then it will
954 * keep the counter running.
955 */
956void perf_counter_task_sched_in(struct task_struct *task, int cpu)
957{
958 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
959 struct perf_counter_context *ctx = &task->perf_counter_ctx;
960
961 __perf_counter_sched_in(ctx, cpuctx, cpu);
962 cpuctx->task_ctx = ctx;
963}
964
965static void perf_counter_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu)
966{
967 struct perf_counter_context *ctx = &cpuctx->ctx;
968
969 __perf_counter_sched_in(ctx, cpuctx, cpu);
970}
971
972int perf_counter_task_disable(void)
973{
974 struct task_struct *curr = current;
975 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
976 struct perf_counter *counter;
977 unsigned long flags;
978
979 if (likely(!ctx->nr_counters))
980 return 0;
981
982 local_irq_save(flags);
983
984 __perf_counter_task_sched_out(ctx);
985
986 spin_lock(&ctx->lock);
987
988 /*
989 * Disable all the counters:
990 */
991 perf_disable();
992
993 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
994 if (counter->state != PERF_COUNTER_STATE_ERROR) {
995 update_group_times(counter);
996 counter->state = PERF_COUNTER_STATE_OFF;
997 }
998 }
999
1000 perf_enable();
1001
1002 spin_unlock_irqrestore(&ctx->lock, flags);
1003
1004 return 0;
1005}
1006
1007int perf_counter_task_enable(void)
1008{
1009 struct task_struct *curr = current;
1010 struct perf_counter_context *ctx = &curr->perf_counter_ctx;
1011 struct perf_counter *counter;
1012 unsigned long flags;
1013 int cpu;
1014
1015 if (likely(!ctx->nr_counters))
1016 return 0;
1017
1018 local_irq_save(flags);
1019 cpu = smp_processor_id();
1020
1021 __perf_counter_task_sched_out(ctx);
1022
1023 spin_lock(&ctx->lock);
1024
1025 /*
1026 * Disable all the counters:
1027 */
1028 perf_disable();
1029
1030 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1031 if (counter->state > PERF_COUNTER_STATE_OFF)
1032 continue;
1033 counter->state = PERF_COUNTER_STATE_INACTIVE;
1034 counter->tstamp_enabled =
1035 ctx->time - counter->total_time_enabled;
1036 counter->hw_event.disabled = 0;
1037 }
1038 perf_enable();
1039
1040 spin_unlock(&ctx->lock);
1041
1042 perf_counter_task_sched_in(curr, cpu);
1043
1044 local_irq_restore(flags);
1045
1046 return 0;
1047}
1048
1049void perf_adjust_freq(struct perf_counter_context *ctx)
1050{
1051 struct perf_counter *counter;
1052 u64 irq_period;
1053 u64 events, period;
1054 s64 delta;
1055
1056 spin_lock(&ctx->lock);
1057 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1058 if (counter->state != PERF_COUNTER_STATE_ACTIVE)
1059 continue;
1060
1061 if (!counter->hw_event.freq || !counter->hw_event.irq_freq)
1062 continue;
1063
1064 events = HZ * counter->hw.interrupts * counter->hw.irq_period;
1065 period = div64_u64(events, counter->hw_event.irq_freq);
1066
1067 delta = (s64)(1 + period - counter->hw.irq_period);
1068 delta >>= 1;
1069
1070 irq_period = counter->hw.irq_period + delta;
1071
1072 if (!irq_period)
1073 irq_period = 1;
1074
1075 counter->hw.irq_period = irq_period;
1076 counter->hw.interrupts = 0;
1077 }
1078 spin_unlock(&ctx->lock);
1079}
1080
1081/*
1082 * Round-robin a context's counters:
1083 */
1084static void rotate_ctx(struct perf_counter_context *ctx)
1085{
1086 struct perf_counter *counter;
1087
1088 if (!ctx->nr_counters)
1089 return;
1090
1091 spin_lock(&ctx->lock);
1092 /*
1093 * Rotate the first entry last (works just fine for group counters too):
1094 */
1095 perf_disable();
1096 list_for_each_entry(counter, &ctx->counter_list, list_entry) {
1097 list_move_tail(&counter->list_entry, &ctx->counter_list);
1098 break;
1099 }
1100 perf_enable();
1101
1102 spin_unlock(&ctx->lock);
1103}
1104
1105void perf_counter_task_tick(struct task_struct *curr, int cpu)
1106{
1107 struct perf_cpu_context *cpuctx;
1108 struct perf_counter_context *ctx;
1109
1110 if (!atomic_read(&nr_counters))
1111 return;
1112
1113 cpuctx = &per_cpu(perf_cpu_context, cpu);
1114 ctx = &curr->perf_counter_ctx;
1115
1116 perf_adjust_freq(&cpuctx->ctx);
1117 perf_adjust_freq(ctx);
1118
1119 perf_counter_cpu_sched_out(cpuctx);
1120 __perf_counter_task_sched_out(ctx);
1121
1122 rotate_ctx(&cpuctx->ctx);
1123 rotate_ctx(ctx);
1124
1125 perf_counter_cpu_sched_in(cpuctx, cpu);
1126 perf_counter_task_sched_in(curr, cpu);
1127}
1128
1129/*
1130 * Cross CPU call to read the hardware counter
1131 */
1132static void __read(void *info)
1133{
1134 struct perf_counter *counter = info;
1135 struct perf_counter_context *ctx = counter->ctx;
1136 unsigned long flags;
1137
1138 local_irq_save(flags);
1139 if (ctx->is_active)
1140 update_context_time(ctx);
1141 counter->pmu->read(counter);
1142 update_counter_times(counter);
1143 local_irq_restore(flags);
1144}
1145
1146static u64 perf_counter_read(struct perf_counter *counter)
1147{
1148 /*
1149 * If counter is enabled and currently active on a CPU, update the
1150 * value in the counter structure:
1151 */
1152 if (counter->state == PERF_COUNTER_STATE_ACTIVE) {
1153 smp_call_function_single(counter->oncpu,
1154 __read, counter, 1);
1155 } else if (counter->state == PERF_COUNTER_STATE_INACTIVE) {
1156 update_counter_times(counter);
1157 }
1158
1159 return atomic64_read(&counter->count);
1160}
1161
1162static void put_context(struct perf_counter_context *ctx)
1163{
1164 if (ctx->task)
1165 put_task_struct(ctx->task);
1166}
1167
1168static struct perf_counter_context *find_get_context(pid_t pid, int cpu)
1169{
1170 struct perf_cpu_context *cpuctx;
1171 struct perf_counter_context *ctx;
1172 struct task_struct *task;
1173
1174 /*
1175 * If cpu is not a wildcard then this is a percpu counter:
1176 */
1177 if (cpu != -1) {
1178 /* Must be root to operate on a CPU counter: */
1179 if (sysctl_perf_counter_priv && !capable(CAP_SYS_ADMIN))
1180 return ERR_PTR(-EACCES);
1181
1182 if (cpu < 0 || cpu > num_possible_cpus())
1183 return ERR_PTR(-EINVAL);
1184
1185 /*
1186 * We could be clever and allow to attach a counter to an
1187 * offline CPU and activate it when the CPU comes up, but
1188 * that's for later.
1189 */
1190 if (!cpu_isset(cpu, cpu_online_map))
1191 return ERR_PTR(-ENODEV);
1192
1193 cpuctx = &per_cpu(perf_cpu_context, cpu);
1194 ctx = &cpuctx->ctx;
1195
1196 return ctx;
1197 }
1198
1199 rcu_read_lock();
1200 if (!pid)
1201 task = current;
1202 else
1203 task = find_task_by_vpid(pid);
1204 if (task)
1205 get_task_struct(task);
1206 rcu_read_unlock();
1207
1208 if (!task)
1209 return ERR_PTR(-ESRCH);
1210
1211 ctx = &task->perf_counter_ctx;
1212 ctx->task = task;
1213
1214 /* Reuse ptrace permission checks for now. */
1215 if (!ptrace_may_access(task, PTRACE_MODE_READ)) {
1216 put_context(ctx);
1217 return ERR_PTR(-EACCES);
1218 }
1219
1220 return ctx;
1221}
1222
1223static void free_counter_rcu(struct rcu_head *head)
1224{
1225 struct perf_counter *counter;
1226
1227 counter = container_of(head, struct perf_counter, rcu_head);
1228 kfree(counter);
1229}
1230
1231static void perf_pending_sync(struct perf_counter *counter);
1232
1233static void free_counter(struct perf_counter *counter)
1234{
1235 perf_pending_sync(counter);
1236
1237 atomic_dec(&nr_counters);
1238 if (counter->hw_event.mmap)
1239 atomic_dec(&nr_mmap_tracking);
1240 if (counter->hw_event.munmap)
1241 atomic_dec(&nr_munmap_tracking);
1242 if (counter->hw_event.comm)
1243 atomic_dec(&nr_comm_tracking);
1244
1245 if (counter->destroy)
1246 counter->destroy(counter);
1247
1248 call_rcu(&counter->rcu_head, free_counter_rcu);
1249}
1250
1251/*
1252 * Called when the last reference to the file is gone.
1253 */
1254static int perf_release(struct inode *inode, struct file *file)
1255{
1256 struct perf_counter *counter = file->private_data;
1257 struct perf_counter_context *ctx = counter->ctx;
1258
1259 file->private_data = NULL;
1260
1261 mutex_lock(&ctx->mutex);
1262 mutex_lock(&counter->mutex);
1263
1264 perf_counter_remove_from_context(counter);
1265
1266 mutex_unlock(&counter->mutex);
1267 mutex_unlock(&ctx->mutex);
1268
1269 free_counter(counter);
1270 put_context(ctx);
1271
1272 return 0;
1273}
1274
1275/*
1276 * Read the performance counter - simple non blocking version for now
1277 */
1278static ssize_t
1279perf_read_hw(struct perf_counter *counter, char __user *buf, size_t count)
1280{
1281 u64 values[3];
1282 int n;
1283
1284 /*
1285 * Return end-of-file for a read on a counter that is in
1286 * error state (i.e. because it was pinned but it couldn't be
1287 * scheduled on to the CPU at some point).
1288 */
1289 if (counter->state == PERF_COUNTER_STATE_ERROR)
1290 return 0;
1291
1292 mutex_lock(&counter->mutex);
1293 values[0] = perf_counter_read(counter);
1294 n = 1;
1295 if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1296 values[n++] = counter->total_time_enabled +
1297 atomic64_read(&counter->child_total_time_enabled);
1298 if (counter->hw_event.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1299 values[n++] = counter->total_time_running +
1300 atomic64_read(&counter->child_total_time_running);
1301 mutex_unlock(&counter->mutex);
1302
1303 if (count < n * sizeof(u64))
1304 return -EINVAL;
1305 count = n * sizeof(u64);
1306
1307 if (copy_to_user(buf, values, count))
1308 return -EFAULT;
1309
1310 return count;
1311}
1312
1313static ssize_t
1314perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
1315{
1316 struct perf_counter *counter = file->private_data;
1317
1318 return perf_read_hw(counter, buf, count);
1319}
1320
1321static unsigned int perf_poll(struct file *file, poll_table *wait)
1322{
1323 struct perf_counter *counter = file->private_data;
1324 struct perf_mmap_data *data;
1325 unsigned int events = POLL_HUP;
1326
1327 rcu_read_lock();
1328 data = rcu_dereference(counter->data);
1329 if (data)
1330 events = atomic_xchg(&data->poll, 0);
1331 rcu_read_unlock();
1332
1333 poll_wait(file, &counter->waitq, wait);
1334
1335 return events;
1336}
1337
1338static void perf_counter_reset(struct perf_counter *counter)
1339{
1340 (void)perf_counter_read(counter);
1341 atomic64_set(&counter->count, 0);
1342 perf_counter_update_userpage(counter);
1343}
1344
1345static void perf_counter_for_each_sibling(struct perf_counter *counter,
1346 void (*func)(struct perf_counter *))
1347{
1348 struct perf_counter_context *ctx = counter->ctx;
1349 struct perf_counter *sibling;
1350
1351 spin_lock_irq(&ctx->lock);
1352 counter = counter->group_leader;
1353
1354 func(counter);
1355 list_for_each_entry(sibling, &counter->sibling_list, list_entry)
1356 func(sibling);
1357 spin_unlock_irq(&ctx->lock);
1358}
1359
1360static void perf_counter_for_each_child(struct perf_counter *counter,
1361 void (*func)(struct perf_counter *))
1362{
1363 struct perf_counter *child;
1364
1365 mutex_lock(&counter->mutex);
1366 func(counter);
1367 list_for_each_entry(child, &counter->child_list, child_list)
1368 func(child);
1369 mutex_unlock(&counter->mutex);
1370}
1371
1372static void perf_counter_for_each(struct perf_counter *counter,
1373 void (*func)(struct perf_counter *))
1374{
1375 struct perf_counter *child;
1376
1377 mutex_lock(&counter->mutex);
1378 perf_counter_for_each_sibling(counter, func);
1379 list_for_each_entry(child, &counter->child_list, child_list)
1380 perf_counter_for_each_sibling(child, func);
1381 mutex_unlock(&counter->mutex);
1382}
1383
1384static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1385{
1386 struct perf_counter *counter = file->private_data;
1387 void (*func)(struct perf_counter *);
1388 u32 flags = arg;
1389
1390 switch (cmd) {
1391 case PERF_COUNTER_IOC_ENABLE:
1392 func = perf_counter_enable;
1393 break;
1394 case PERF_COUNTER_IOC_DISABLE:
1395 func = perf_counter_disable;
1396 break;
1397 case PERF_COUNTER_IOC_RESET:
1398 func = perf_counter_reset;
1399 break;
1400
1401 case PERF_COUNTER_IOC_REFRESH:
1402 return perf_counter_refresh(counter, arg);
1403 default:
1404 return -ENOTTY;
1405 }
1406
1407 if (flags & PERF_IOC_FLAG_GROUP)
1408 perf_counter_for_each(counter, func);
1409 else
1410 perf_counter_for_each_child(counter, func);
1411
1412 return 0;
1413}
1414
1415/*
1416 * Callers need to ensure there can be no nesting of this function, otherwise
1417 * the seqlock logic goes bad. We can not serialize this because the arch
1418 * code calls this from NMI context.
1419 */
1420void perf_counter_update_userpage(struct perf_counter *counter)
1421{
1422 struct perf_mmap_data *data;
1423 struct perf_counter_mmap_page *userpg;
1424
1425 rcu_read_lock();
1426 data = rcu_dereference(counter->data);
1427 if (!data)
1428 goto unlock;
1429
1430 userpg = data->user_page;
1431
1432 /*
1433 * Disable preemption so as to not let the corresponding user-space
1434 * spin too long if we get preempted.
1435 */
1436 preempt_disable();
1437 ++userpg->lock;
1438 barrier();
1439 userpg->index = counter->hw.idx;
1440 userpg->offset = atomic64_read(&counter->count);
1441 if (counter->state == PERF_COUNTER_STATE_ACTIVE)
1442 userpg->offset -= atomic64_read(&counter->hw.prev_count);
1443
1444 barrier();
1445 ++userpg->lock;
1446 preempt_enable();
1447unlock:
1448 rcu_read_unlock();
1449}
1450
1451static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1452{
1453 struct perf_counter *counter = vma->vm_file->private_data;
1454 struct perf_mmap_data *data;
1455 int ret = VM_FAULT_SIGBUS;
1456
1457 rcu_read_lock();
1458 data = rcu_dereference(counter->data);
1459 if (!data)
1460 goto unlock;
1461
1462 if (vmf->pgoff == 0) {
1463 vmf->page = virt_to_page(data->user_page);
1464 } else {
1465 int nr = vmf->pgoff - 1;
1466
1467 if ((unsigned)nr > data->nr_pages)
1468 goto unlock;
1469
1470 vmf->page = virt_to_page(data->data_pages[nr]);
1471 }
1472 get_page(vmf->page);
1473 ret = 0;
1474unlock:
1475 rcu_read_unlock();
1476
1477 return ret;
1478}
1479
1480static int perf_mmap_data_alloc(struct perf_counter *counter, int nr_pages)
1481{
1482 struct perf_mmap_data *data;
1483 unsigned long size;
1484 int i;
1485
1486 WARN_ON(atomic_read(&counter->mmap_count));
1487
1488 size = sizeof(struct perf_mmap_data);
1489 size += nr_pages * sizeof(void *);
1490
1491 data = kzalloc(size, GFP_KERNEL);
1492 if (!data)
1493 goto fail;
1494
1495 data->user_page = (void *)get_zeroed_page(GFP_KERNEL);
1496 if (!data->user_page)
1497 goto fail_user_page;
1498
1499 for (i = 0; i < nr_pages; i++) {
1500 data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL);
1501 if (!data->data_pages[i])
1502 goto fail_data_pages;
1503 }
1504
1505 data->nr_pages = nr_pages;
1506 atomic_set(&data->lock, -1);
1507
1508 rcu_assign_pointer(counter->data, data);
1509
1510 return 0;
1511
1512fail_data_pages:
1513 for (i--; i >= 0; i--)
1514 free_page((unsigned long)data->data_pages[i]);
1515
1516 free_page((unsigned long)data->user_page);
1517
1518fail_user_page:
1519 kfree(data);
1520
1521fail:
1522 return -ENOMEM;
1523}
1524
1525static void __perf_mmap_data_free(struct rcu_head *rcu_head)
1526{
1527 struct perf_mmap_data *data = container_of(rcu_head,
1528 struct perf_mmap_data, rcu_head);
1529 int i;
1530
1531 free_page((unsigned long)data->user_page);
1532 for (i = 0; i < data->nr_pages; i++)
1533 free_page((unsigned long)data->data_pages[i]);
1534 kfree(data);
1535}
1536
1537static void perf_mmap_data_free(struct perf_counter *counter)
1538{
1539 struct perf_mmap_data *data = counter->data;
1540
1541 WARN_ON(atomic_read(&counter->mmap_count));
1542
1543 rcu_assign_pointer(counter->data, NULL);
1544 call_rcu(&data->rcu_head, __perf_mmap_data_free);
1545}
1546
1547static void perf_mmap_open(struct vm_area_struct *vma)
1548{
1549 struct perf_counter *counter = vma->vm_file->private_data;
1550
1551 atomic_inc(&counter->mmap_count);
1552}
1553
1554static void perf_mmap_close(struct vm_area_struct *vma)
1555{
1556 struct perf_counter *counter = vma->vm_file->private_data;
1557
1558 if (atomic_dec_and_mutex_lock(&counter->mmap_count,
1559 &counter->mmap_mutex)) {
1560 struct user_struct *user = current_user();
1561
1562 atomic_long_sub(counter->data->nr_pages + 1, &user->locked_vm);
1563 vma->vm_mm->locked_vm -= counter->data->nr_locked;
1564 perf_mmap_data_free(counter);
1565 mutex_unlock(&counter->mmap_mutex);
1566 }
1567}
1568
1569static struct vm_operations_struct perf_mmap_vmops = {
1570 .open = perf_mmap_open,
1571 .close = perf_mmap_close,
1572 .fault = perf_mmap_fault,
1573};
1574
1575static int perf_mmap(struct file *file, struct vm_area_struct *vma)
1576{
1577 struct perf_counter *counter = file->private_data;
1578 struct user_struct *user = current_user();
1579 unsigned long vma_size;
1580 unsigned long nr_pages;
1581 unsigned long user_locked, user_lock_limit;
1582 unsigned long locked, lock_limit;
1583 long user_extra, extra;
1584 int ret = 0;
1585
1586 if (!(vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_WRITE))
1587 return -EINVAL;
1588
1589 vma_size = vma->vm_end - vma->vm_start;
1590 nr_pages = (vma_size / PAGE_SIZE) - 1;
1591
1592 /*
1593 * If we have data pages ensure they're a power-of-two number, so we
1594 * can do bitmasks instead of modulo.
1595 */
1596 if (nr_pages != 0 && !is_power_of_2(nr_pages))
1597 return -EINVAL;
1598
1599 if (vma_size != PAGE_SIZE * (1 + nr_pages))
1600 return -EINVAL;
1601
1602 if (vma->vm_pgoff != 0)
1603 return -EINVAL;
1604
1605 mutex_lock(&counter->mmap_mutex);
1606 if (atomic_inc_not_zero(&counter->mmap_count)) {
1607 if (nr_pages != counter->data->nr_pages)
1608 ret = -EINVAL;
1609 goto unlock;
1610 }
1611
1612 user_extra = nr_pages + 1;
1613 user_lock_limit = sysctl_perf_counter_mlock >> (PAGE_SHIFT - 10);
1614 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
1615
1616 extra = 0;
1617 if (user_locked > user_lock_limit)
1618 extra = user_locked - user_lock_limit;
1619
1620 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
1621 lock_limit >>= PAGE_SHIFT;
1622 locked = vma->vm_mm->locked_vm + extra;
1623
1624 if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
1625 ret = -EPERM;
1626 goto unlock;
1627 }
1628
1629 WARN_ON(counter->data);
1630 ret = perf_mmap_data_alloc(counter, nr_pages);
1631 if (ret)
1632 goto unlock;
1633
1634 atomic_set(&counter->mmap_count, 1);
1635 atomic_long_add(user_extra, &user->locked_vm);
1636 vma->vm_mm->locked_vm += extra;
1637 counter->data->nr_locked = extra;
1638unlock:
1639 mutex_unlock(&counter->mmap_mutex);
1640
1641 vma->vm_flags &= ~VM_MAYWRITE;
1642 vma->vm_flags |= VM_RESERVED;
1643 vma->vm_ops = &perf_mmap_vmops;
1644
1645 return ret;
1646}
1647
1648static int perf_fasync(int fd, struct file *filp, int on)
1649{
1650 struct perf_counter *counter = filp->private_data;
1651 struct inode *inode = filp->f_path.dentry->d_inode;
1652 int retval;
1653
1654 mutex_lock(&inode->i_mutex);
1655 retval = fasync_helper(fd, filp, on, &counter->fasync);
1656 mutex_unlock(&inode->i_mutex);
1657
1658 if (retval < 0)
1659 return retval;
1660
1661 return 0;
1662}
1663
1664static const struct file_operations perf_fops = {
1665 .release = perf_release,
1666 .read = perf_read,
1667 .poll = perf_poll,
1668 .unlocked_ioctl = perf_ioctl,
1669 .compat_ioctl = perf_ioctl,
1670 .mmap = perf_mmap,
1671 .fasync = perf_fasync,
1672};
1673
1674/*
1675 * Perf counter wakeup
1676 *
1677 * If there's data, ensure we set the poll() state and publish everything
1678 * to user-space before waking everybody up.
1679 */
1680
1681void perf_counter_wakeup(struct perf_counter *counter)
1682{
1683 wake_up_all(&counter->waitq);
1684
1685 if (counter->pending_kill) {
1686 kill_fasync(&counter->fasync, SIGIO, counter->pending_kill);
1687 counter->pending_kill = 0;
1688 }
1689}
1690
1691/*
1692 * Pending wakeups
1693 *
1694 * Handle the case where we need to wakeup up from NMI (or rq->lock) context.
1695 *
1696 * The NMI bit means we cannot possibly take locks. Therefore, maintain a
1697 * single linked list and use cmpxchg() to add entries lockless.
1698 */
1699
1700static void perf_pending_counter(struct perf_pending_entry *entry)
1701{
1702 struct perf_counter *counter = container_of(entry,
1703 struct perf_counter, pending);
1704
1705 if (counter->pending_disable) {
1706 counter->pending_disable = 0;
1707 perf_counter_disable(counter);
1708 }
1709
1710 if (counter->pending_wakeup) {
1711 counter->pending_wakeup = 0;
1712 perf_counter_wakeup(counter);
1713 }
1714}
1715
1716#define PENDING_TAIL ((struct perf_pending_entry *)-1UL)
1717
1718static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = {
1719 PENDING_TAIL,
1720};
1721
1722static void perf_pending_queue(struct perf_pending_entry *entry,
1723 void (*func)(struct perf_pending_entry *))
1724{
1725 struct perf_pending_entry **head;
1726
1727 if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL)
1728 return;
1729
1730 entry->func = func;
1731
1732 head = &get_cpu_var(perf_pending_head);
1733
1734 do {
1735 entry->next = *head;
1736 } while (cmpxchg(head, entry->next, entry) != entry->next);
1737
1738 set_perf_counter_pending();
1739
1740 put_cpu_var(perf_pending_head);
1741}
1742
1743static int __perf_pending_run(void)
1744{
1745 struct perf_pending_entry *list;
1746 int nr = 0;
1747
1748 list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL);
1749 while (list != PENDING_TAIL) {
1750 void (*func)(struct perf_pending_entry *);
1751 struct perf_pending_entry *entry = list;
1752
1753 list = list->next;
1754
1755 func = entry->func;
1756 entry->next = NULL;
1757 /*
1758 * Ensure we observe the unqueue before we issue the wakeup,
1759 * so that we won't be waiting forever.
1760 * -- see perf_not_pending().
1761 */
1762 smp_wmb();
1763
1764 func(entry);
1765 nr++;
1766 }
1767
1768 return nr;
1769}
1770
1771static inline int perf_not_pending(struct perf_counter *counter)
1772{
1773 /*
1774 * If we flush on whatever cpu we run, there is a chance we don't
1775 * need to wait.
1776 */
1777 get_cpu();
1778 __perf_pending_run();
1779 put_cpu();
1780
1781 /*
1782 * Ensure we see the proper queue state before going to sleep
1783 * so that we do not miss the wakeup. -- see perf_pending_handle()
1784 */
1785 smp_rmb();
1786 return counter->pending.next == NULL;
1787}
1788
1789static void perf_pending_sync(struct perf_counter *counter)
1790{
1791 wait_event(counter->waitq, perf_not_pending(counter));
1792}
1793
1794void perf_counter_do_pending(void)
1795{
1796 __perf_pending_run();
1797}
1798
1799/*
1800 * Callchain support -- arch specific
1801 */
1802
1803__weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
1804{
1805 return NULL;
1806}
1807
1808/*
1809 * Output
1810 */
1811
1812struct perf_output_handle {
1813 struct perf_counter *counter;
1814 struct perf_mmap_data *data;
1815 unsigned int offset;
1816 unsigned int head;
1817 int nmi;
1818 int overflow;
1819 int locked;
1820 unsigned long flags;
1821};
1822
1823static void perf_output_wakeup(struct perf_output_handle *handle)
1824{
1825 atomic_set(&handle->data->poll, POLL_IN);
1826
1827 if (handle->nmi) {
1828 handle->counter->pending_wakeup = 1;
1829 perf_pending_queue(&handle->counter->pending,
1830 perf_pending_counter);
1831 } else
1832 perf_counter_wakeup(handle->counter);
1833}
1834
1835/*
1836 * Curious locking construct.
1837 *
1838 * We need to ensure a later event doesn't publish a head when a former
1839 * event isn't done writing. However since we need to deal with NMIs we
1840 * cannot fully serialize things.
1841 *
1842 * What we do is serialize between CPUs so we only have to deal with NMI
1843 * nesting on a single CPU.
1844 *
1845 * We only publish the head (and generate a wakeup) when the outer-most
1846 * event completes.
1847 */
1848static void perf_output_lock(struct perf_output_handle *handle)
1849{
1850 struct perf_mmap_data *data = handle->data;
1851 int cpu;
1852
1853 handle->locked = 0;
1854
1855 local_irq_save(handle->flags);
1856 cpu = smp_processor_id();
1857
1858 if (in_nmi() && atomic_read(&data->lock) == cpu)
1859 return;
1860
1861 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
1862 cpu_relax();
1863
1864 handle->locked = 1;
1865}
1866
1867static void perf_output_unlock(struct perf_output_handle *handle)
1868{
1869 struct perf_mmap_data *data = handle->data;
1870 int head, cpu;
1871
1872 data->done_head = data->head;
1873
1874 if (!handle->locked)
1875 goto out;
1876
1877again:
1878 /*
1879 * The xchg implies a full barrier that ensures all writes are done
1880 * before we publish the new head, matched by a rmb() in userspace when
1881 * reading this position.
1882 */
1883 while ((head = atomic_xchg(&data->done_head, 0)))
1884 data->user_page->data_head = head;
1885
1886 /*
1887 * NMI can happen here, which means we can miss a done_head update.
1888 */
1889
1890 cpu = atomic_xchg(&data->lock, -1);
1891 WARN_ON_ONCE(cpu != smp_processor_id());
1892
1893 /*
1894 * Therefore we have to validate we did not indeed do so.
1895 */
1896 if (unlikely(atomic_read(&data->done_head))) {
1897 /*
1898 * Since we had it locked, we can lock it again.
1899 */
1900 while (atomic_cmpxchg(&data->lock, -1, cpu) != -1)
1901 cpu_relax();
1902
1903 goto again;
1904 }
1905
1906 if (atomic_xchg(&data->wakeup, 0))
1907 perf_output_wakeup(handle);
1908out:
1909 local_irq_restore(handle->flags);
1910}
1911
1912static int perf_output_begin(struct perf_output_handle *handle,
1913 struct perf_counter *counter, unsigned int size,
1914 int nmi, int overflow)
1915{
1916 struct perf_mmap_data *data;
1917 unsigned int offset, head;
1918
1919 /*
1920 * For inherited counters we send all the output towards the parent.
1921 */
1922 if (counter->parent)
1923 counter = counter->parent;
1924
1925 rcu_read_lock();
1926 data = rcu_dereference(counter->data);
1927 if (!data)
1928 goto out;
1929
1930 handle->data = data;
1931 handle->counter = counter;
1932 handle->nmi = nmi;
1933 handle->overflow = overflow;
1934
1935 if (!data->nr_pages)
1936 goto fail;
1937
1938 perf_output_lock(handle);
1939
1940 do {
1941 offset = head = atomic_read(&data->head);
1942 head += size;
1943 } while (atomic_cmpxchg(&data->head, offset, head) != offset);
1944
1945 handle->offset = offset;
1946 handle->head = head;
1947
1948 if ((offset >> PAGE_SHIFT) != (head >> PAGE_SHIFT))
1949 atomic_set(&data->wakeup, 1);
1950
1951 return 0;
1952
1953fail:
1954 perf_output_wakeup(handle);
1955out:
1956 rcu_read_unlock();
1957
1958 return -ENOSPC;
1959}
1960
1961static void perf_output_copy(struct perf_output_handle *handle,
1962 void *buf, unsigned int len)
1963{
1964 unsigned int pages_mask;
1965 unsigned int offset;
1966 unsigned int size;
1967 void **pages;
1968
1969 offset = handle->offset;
1970 pages_mask = handle->data->nr_pages - 1;
1971 pages = handle->data->data_pages;
1972
1973 do {
1974 unsigned int page_offset;
1975 int nr;
1976
1977 nr = (offset >> PAGE_SHIFT) & pages_mask;
1978 page_offset = offset & (PAGE_SIZE - 1);
1979 size = min_t(unsigned int, PAGE_SIZE - page_offset, len);
1980
1981 memcpy(pages[nr] + page_offset, buf, size);
1982
1983 len -= size;
1984 buf += size;
1985 offset += size;
1986 } while (len);
1987
1988 handle->offset = offset;
1989
1990 /*
1991 * Check we didn't copy past our reservation window, taking the
1992 * possible unsigned int wrap into account.
1993 */
1994 WARN_ON_ONCE(((int)(handle->head - handle->offset)) < 0);
1995}
1996
1997#define perf_output_put(handle, x) \
1998 perf_output_copy((handle), &(x), sizeof(x))
1999
2000static void perf_output_end(struct perf_output_handle *handle)
2001{
2002 struct perf_counter *counter = handle->counter;
2003 struct perf_mmap_data *data = handle->data;
2004
2005 int wakeup_events = counter->hw_event.wakeup_events;
2006
2007 if (handle->overflow && wakeup_events) {
2008 int events = atomic_inc_return(&data->events);
2009 if (events >= wakeup_events) {
2010 atomic_sub(wakeup_events, &data->events);
2011 atomic_set(&data->wakeup, 1);
2012 }
2013 }
2014
2015 perf_output_unlock(handle);
2016 rcu_read_unlock();
2017}
2018
2019static void perf_counter_output(struct perf_counter *counter,
2020 int nmi, struct pt_regs *regs, u64 addr)
2021{
2022 int ret;
2023 u64 record_type = counter->hw_event.record_type;
2024 struct perf_output_handle handle;
2025 struct perf_event_header header;
2026 u64 ip;
2027 struct {
2028 u32 pid, tid;
2029 } tid_entry;
2030 struct {
2031 u64 event;
2032 u64 counter;
2033 } group_entry;
2034 struct perf_callchain_entry *callchain = NULL;
2035 int callchain_size = 0;
2036 u64 time;
2037 struct {
2038 u32 cpu, reserved;
2039 } cpu_entry;
2040
2041 header.type = 0;
2042 header.size = sizeof(header);
2043
2044 header.misc = PERF_EVENT_MISC_OVERFLOW;
2045 header.misc |= perf_misc_flags(regs);
2046
2047 if (record_type & PERF_RECORD_IP) {
2048 ip = perf_instruction_pointer(regs);
2049 header.type |= PERF_RECORD_IP;
2050 header.size += sizeof(ip);
2051 }
2052
2053 if (record_type & PERF_RECORD_TID) {
2054 /* namespace issues */
2055 tid_entry.pid = current->group_leader->pid;
2056 tid_entry.tid = current->pid;
2057
2058 header.type |= PERF_RECORD_TID;
2059 header.size += sizeof(tid_entry);
2060 }
2061
2062 if (record_type & PERF_RECORD_TIME) {
2063 /*
2064 * Maybe do better on x86 and provide cpu_clock_nmi()
2065 */
2066 time = sched_clock();
2067
2068 header.type |= PERF_RECORD_TIME;
2069 header.size += sizeof(u64);
2070 }
2071
2072 if (record_type & PERF_RECORD_ADDR) {
2073 header.type |= PERF_RECORD_ADDR;
2074 header.size += sizeof(u64);
2075 }
2076
2077 if (record_type & PERF_RECORD_CONFIG) {
2078 header.type |= PERF_RECORD_CONFIG;
2079 header.size += sizeof(u64);
2080 }
2081
2082 if (record_type & PERF_RECORD_CPU) {
2083 header.type |= PERF_RECORD_CPU;
2084 header.size += sizeof(cpu_entry);
2085
2086 cpu_entry.cpu = raw_smp_processor_id();
2087 }
2088
2089 if (record_type & PERF_RECORD_GROUP) {
2090 header.type |= PERF_RECORD_GROUP;
2091 header.size += sizeof(u64) +
2092 counter->nr_siblings * sizeof(group_entry);
2093 }
2094
2095 if (record_type & PERF_RECORD_CALLCHAIN) {
2096 callchain = perf_callchain(regs);
2097
2098 if (callchain) {
2099 callchain_size = (1 + callchain->nr) * sizeof(u64);
2100
2101 header.type |= PERF_RECORD_CALLCHAIN;
2102 header.size += callchain_size;
2103 }
2104 }
2105
2106 ret = perf_output_begin(&handle, counter, header.size, nmi, 1);
2107 if (ret)
2108 return;
2109
2110 perf_output_put(&handle, header);
2111
2112 if (record_type & PERF_RECORD_IP)
2113 perf_output_put(&handle, ip);
2114
2115 if (record_type & PERF_RECORD_TID)
2116 perf_output_put(&handle, tid_entry);
2117
2118 if (record_type & PERF_RECORD_TIME)
2119 perf_output_put(&handle, time);
2120
2121 if (record_type & PERF_RECORD_ADDR)
2122 perf_output_put(&handle, addr);
2123
2124 if (record_type & PERF_RECORD_CONFIG)
2125 perf_output_put(&handle, counter->hw_event.config);
2126
2127 if (record_type & PERF_RECORD_CPU)
2128 perf_output_put(&handle, cpu_entry);
2129
2130 /*
2131 * XXX PERF_RECORD_GROUP vs inherited counters seems difficult.
2132 */
2133 if (record_type & PERF_RECORD_GROUP) {
2134 struct perf_counter *leader, *sub;
2135 u64 nr = counter->nr_siblings;
2136
2137 perf_output_put(&handle, nr);
2138
2139 leader = counter->group_leader;
2140 list_for_each_entry(sub, &leader->sibling_list, list_entry) {
2141 if (sub != counter)
2142 sub->pmu->read(sub);
2143
2144 group_entry.event = sub->hw_event.config;
2145 group_entry.counter = atomic64_read(&sub->count);
2146
2147 perf_output_put(&handle, group_entry);
2148 }
2149 }
2150
2151 if (callchain)
2152 perf_output_copy(&handle, callchain, callchain_size);
2153
2154 perf_output_end(&handle);
2155}
2156
2157/*
2158 * comm tracking
2159 */
2160
2161struct perf_comm_event {
2162 struct task_struct *task;
2163 char *comm;
2164 int comm_size;
2165
2166 struct {
2167 struct perf_event_header header;
2168
2169 u32 pid;
2170 u32 tid;
2171 } event;
2172};
2173
2174static void perf_counter_comm_output(struct perf_counter *counter,
2175 struct perf_comm_event *comm_event)
2176{
2177 struct perf_output_handle handle;
2178 int size = comm_event->event.header.size;
2179 int ret = perf_output_begin(&handle, counter, size, 0, 0);
2180
2181 if (ret)
2182 return;
2183
2184 perf_output_put(&handle, comm_event->event);
2185 perf_output_copy(&handle, comm_event->comm,
2186 comm_event->comm_size);
2187 perf_output_end(&handle);
2188}
2189
2190static int perf_counter_comm_match(struct perf_counter *counter,
2191 struct perf_comm_event *comm_event)
2192{
2193 if (counter->hw_event.comm &&
2194 comm_event->event.header.type == PERF_EVENT_COMM)
2195 return 1;
2196
2197 return 0;
2198}
2199
2200static void perf_counter_comm_ctx(struct perf_counter_context *ctx,
2201 struct perf_comm_event *comm_event)
2202{
2203 struct perf_counter *counter;
2204
2205 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
2206 return;
2207
2208 rcu_read_lock();
2209 list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
2210 if (perf_counter_comm_match(counter, comm_event))
2211 perf_counter_comm_output(counter, comm_event);
2212 }
2213 rcu_read_unlock();
2214}
2215
2216static void perf_counter_comm_event(struct perf_comm_event *comm_event)
2217{
2218 struct perf_cpu_context *cpuctx;
2219 unsigned int size;
2220 char *comm = comm_event->task->comm;
2221
2222 size = ALIGN(strlen(comm)+1, sizeof(u64));
2223
2224 comm_event->comm = comm;
2225 comm_event->comm_size = size;
2226
2227 comm_event->event.header.size = sizeof(comm_event->event) + size;
2228
2229 cpuctx = &get_cpu_var(perf_cpu_context);
2230 perf_counter_comm_ctx(&cpuctx->ctx, comm_event);
2231 put_cpu_var(perf_cpu_context);
2232
2233 perf_counter_comm_ctx(&current->perf_counter_ctx, comm_event);
2234}
2235
2236void perf_counter_comm(struct task_struct *task)
2237{
2238 struct perf_comm_event comm_event;
2239
2240 if (!atomic_read(&nr_comm_tracking))
2241 return;
2242
2243 comm_event = (struct perf_comm_event){
2244 .task = task,
2245 .event = {
2246 .header = { .type = PERF_EVENT_COMM, },
2247 .pid = task->group_leader->pid,
2248 .tid = task->pid,
2249 },
2250 };
2251
2252 perf_counter_comm_event(&comm_event);
2253}
2254
2255/*
2256 * mmap tracking
2257 */
2258
2259struct perf_mmap_event {
2260 struct file *file;
2261 char *file_name;
2262 int file_size;
2263
2264 struct {
2265 struct perf_event_header header;
2266
2267 u32 pid;
2268 u32 tid;
2269 u64 start;
2270 u64 len;
2271 u64 pgoff;
2272 } event;
2273};
2274
2275static void perf_counter_mmap_output(struct perf_counter *counter,
2276 struct perf_mmap_event *mmap_event)
2277{
2278 struct perf_output_handle handle;
2279 int size = mmap_event->event.header.size;
2280 int ret = perf_output_begin(&handle, counter, size, 0, 0);
2281
2282 if (ret)
2283 return;
2284
2285 perf_output_put(&handle, mmap_event->event);
2286 perf_output_copy(&handle, mmap_event->file_name,
2287 mmap_event->file_size);
2288 perf_output_end(&handle);
2289}
2290
2291static int perf_counter_mmap_match(struct perf_counter *counter,
2292 struct perf_mmap_event *mmap_event)
2293{
2294 if (counter->hw_event.mmap &&
2295 mmap_event->event.header.type == PERF_EVENT_MMAP)
2296 return 1;
2297
2298 if (counter->hw_event.munmap &&
2299 mmap_event->event.header.type == PERF_EVENT_MUNMAP)
2300 return 1;
2301
2302 return 0;
2303}
2304
2305static void perf_counter_mmap_ctx(struct perf_counter_context *ctx,
2306 struct perf_mmap_event *mmap_event)
2307{
2308 struct perf_counter *counter;
2309
2310 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
2311 return;
2312
2313 rcu_read_lock();
2314 list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
2315 if (perf_counter_mmap_match(counter, mmap_event))
2316 perf_counter_mmap_output(counter, mmap_event);
2317 }
2318 rcu_read_unlock();
2319}
2320
2321static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
2322{
2323 struct perf_cpu_context *cpuctx;
2324 struct file *file = mmap_event->file;
2325 unsigned int size;
2326 char tmp[16];
2327 char *buf = NULL;
2328 char *name;
2329
2330 if (file) {
2331 buf = kzalloc(PATH_MAX, GFP_KERNEL);
2332 if (!buf) {
2333 name = strncpy(tmp, "//enomem", sizeof(tmp));
2334 goto got_name;
2335 }
2336 name = d_path(&file->f_path, buf, PATH_MAX);
2337 if (IS_ERR(name)) {
2338 name = strncpy(tmp, "//toolong", sizeof(tmp));
2339 goto got_name;
2340 }
2341 } else {
2342 name = strncpy(tmp, "//anon", sizeof(tmp));
2343 goto got_name;
2344 }
2345
2346got_name:
2347 size = ALIGN(strlen(name)+1, sizeof(u64));
2348
2349 mmap_event->file_name = name;
2350 mmap_event->file_size = size;
2351
2352 mmap_event->event.header.size = sizeof(mmap_event->event) + size;
2353
2354 cpuctx = &get_cpu_var(perf_cpu_context);
2355 perf_counter_mmap_ctx(&cpuctx->ctx, mmap_event);
2356 put_cpu_var(perf_cpu_context);
2357
2358 perf_counter_mmap_ctx(&current->perf_counter_ctx, mmap_event);
2359
2360 kfree(buf);
2361}
2362
2363void perf_counter_mmap(unsigned long addr, unsigned long len,
2364 unsigned long pgoff, struct file *file)
2365{
2366 struct perf_mmap_event mmap_event;
2367
2368 if (!atomic_read(&nr_mmap_tracking))
2369 return;
2370
2371 mmap_event = (struct perf_mmap_event){
2372 .file = file,
2373 .event = {
2374 .header = { .type = PERF_EVENT_MMAP, },
2375 .pid = current->group_leader->pid,
2376 .tid = current->pid,
2377 .start = addr,
2378 .len = len,
2379 .pgoff = pgoff,
2380 },
2381 };
2382
2383 perf_counter_mmap_event(&mmap_event);
2384}
2385
2386void perf_counter_munmap(unsigned long addr, unsigned long len,
2387 unsigned long pgoff, struct file *file)
2388{
2389 struct perf_mmap_event mmap_event;
2390
2391 if (!atomic_read(&nr_munmap_tracking))
2392 return;
2393
2394 mmap_event = (struct perf_mmap_event){
2395 .file = file,
2396 .event = {
2397 .header = { .type = PERF_EVENT_MUNMAP, },
2398 .pid = current->group_leader->pid,
2399 .tid = current->pid,
2400 .start = addr,
2401 .len = len,
2402 .pgoff = pgoff,
2403 },
2404 };
2405
2406 perf_counter_mmap_event(&mmap_event);
2407}
2408
2409/*
2410 * Generic counter overflow handling.
2411 */
2412
2413int perf_counter_overflow(struct perf_counter *counter,
2414 int nmi, struct pt_regs *regs, u64 addr)
2415{
2416 int events = atomic_read(&counter->event_limit);
2417 int ret = 0;
2418
2419 counter->hw.interrupts++;
2420
2421 /*
2422 * XXX event_limit might not quite work as expected on inherited
2423 * counters
2424 */
2425
2426 counter->pending_kill = POLL_IN;
2427 if (events && atomic_dec_and_test(&counter->event_limit)) {
2428 ret = 1;
2429 counter->pending_kill = POLL_HUP;
2430 if (nmi) {
2431 counter->pending_disable = 1;
2432 perf_pending_queue(&counter->pending,
2433 perf_pending_counter);
2434 } else
2435 perf_counter_disable(counter);
2436 }
2437
2438 perf_counter_output(counter, nmi, regs, addr);
2439 return ret;
2440}
2441
2442/*
2443 * Generic software counter infrastructure
2444 */
2445
2446static void perf_swcounter_update(struct perf_counter *counter)
2447{
2448 struct hw_perf_counter *hwc = &counter->hw;
2449 u64 prev, now;
2450 s64 delta;
2451
2452again:
2453 prev = atomic64_read(&hwc->prev_count);
2454 now = atomic64_read(&hwc->count);
2455 if (atomic64_cmpxchg(&hwc->prev_count, prev, now) != prev)
2456 goto again;
2457
2458 delta = now - prev;
2459
2460 atomic64_add(delta, &counter->count);
2461 atomic64_sub(delta, &hwc->period_left);
2462}
2463
2464static void perf_swcounter_set_period(struct perf_counter *counter)
2465{
2466 struct hw_perf_counter *hwc = &counter->hw;
2467 s64 left = atomic64_read(&hwc->period_left);
2468 s64 period = hwc->irq_period;
2469
2470 if (unlikely(left <= -period)) {
2471 left = period;
2472 atomic64_set(&hwc->period_left, left);
2473 }
2474
2475 if (unlikely(left <= 0)) {
2476 left += period;
2477 atomic64_add(period, &hwc->period_left);
2478 }
2479
2480 atomic64_set(&hwc->prev_count, -left);
2481 atomic64_set(&hwc->count, -left);
2482}
2483
2484static enum hrtimer_restart perf_swcounter_hrtimer(struct hrtimer *hrtimer)
2485{
2486 enum hrtimer_restart ret = HRTIMER_RESTART;
2487 struct perf_counter *counter;
2488 struct pt_regs *regs;
2489 u64 period;
2490
2491 counter = container_of(hrtimer, struct perf_counter, hw.hrtimer);
2492 counter->pmu->read(counter);
2493
2494 regs = get_irq_regs();
2495 /*
2496 * In case we exclude kernel IPs or are somehow not in interrupt
2497 * context, provide the next best thing, the user IP.
2498 */
2499 if ((counter->hw_event.exclude_kernel || !regs) &&
2500 !counter->hw_event.exclude_user)
2501 regs = task_pt_regs(current);
2502
2503 if (regs) {
2504 if (perf_counter_overflow(counter, 0, regs, 0))
2505 ret = HRTIMER_NORESTART;
2506 }
2507
2508 period = max_t(u64, 10000, counter->hw.irq_period);
2509 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
2510
2511 return ret;
2512}
2513
2514static void perf_swcounter_overflow(struct perf_counter *counter,
2515 int nmi, struct pt_regs *regs, u64 addr)
2516{
2517 perf_swcounter_update(counter);
2518 perf_swcounter_set_period(counter);
2519 if (perf_counter_overflow(counter, nmi, regs, addr))
2520 /* soft-disable the counter */
2521 ;
2522
2523}
2524
2525static int perf_swcounter_match(struct perf_counter *counter,
2526 enum perf_event_types type,
2527 u32 event, struct pt_regs *regs)
2528{
2529 if (counter->state != PERF_COUNTER_STATE_ACTIVE)
2530 return 0;
2531
2532 if (perf_event_raw(&counter->hw_event))
2533 return 0;
2534
2535 if (perf_event_type(&counter->hw_event) != type)
2536 return 0;
2537
2538 if (perf_event_id(&counter->hw_event) != event)
2539 return 0;
2540
2541 if (counter->hw_event.exclude_user && user_mode(regs))
2542 return 0;
2543
2544 if (counter->hw_event.exclude_kernel && !user_mode(regs))
2545 return 0;
2546
2547 return 1;
2548}
2549
2550static void perf_swcounter_add(struct perf_counter *counter, u64 nr,
2551 int nmi, struct pt_regs *regs, u64 addr)
2552{
2553 int neg = atomic64_add_negative(nr, &counter->hw.count);
2554 if (counter->hw.irq_period && !neg)
2555 perf_swcounter_overflow(counter, nmi, regs, addr);
2556}
2557
2558static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
2559 enum perf_event_types type, u32 event,
2560 u64 nr, int nmi, struct pt_regs *regs,
2561 u64 addr)
2562{
2563 struct perf_counter *counter;
2564
2565 if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
2566 return;
2567
2568 rcu_read_lock();
2569 list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
2570 if (perf_swcounter_match(counter, type, event, regs))
2571 perf_swcounter_add(counter, nr, nmi, regs, addr);
2572 }
2573 rcu_read_unlock();
2574}
2575
2576static int *perf_swcounter_recursion_context(struct perf_cpu_context *cpuctx)
2577{
2578 if (in_nmi())
2579 return &cpuctx->recursion[3];
2580
2581 if (in_irq())
2582 return &cpuctx->recursion[2];
2583
2584 if (in_softirq())
2585 return &cpuctx->recursion[1];
2586
2587 return &cpuctx->recursion[0];
2588}
2589
2590static void __perf_swcounter_event(enum perf_event_types type, u32 event,
2591 u64 nr, int nmi, struct pt_regs *regs,
2592 u64 addr)
2593{
2594 struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);
2595 int *recursion = perf_swcounter_recursion_context(cpuctx);
2596
2597 if (*recursion)
2598 goto out;
2599
2600 (*recursion)++;
2601 barrier();
2602
2603 perf_swcounter_ctx_event(&cpuctx->ctx, type, event,
2604 nr, nmi, regs, addr);
2605 if (cpuctx->task_ctx) {
2606 perf_swcounter_ctx_event(cpuctx->task_ctx, type, event,
2607 nr, nmi, regs, addr);
2608 }
2609
2610 barrier();
2611 (*recursion)--;
2612
2613out:
2614 put_cpu_var(perf_cpu_context);
2615}
2616
2617void
2618perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
2619{
2620 __perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, regs, addr);
2621}
2622
2623static void perf_swcounter_read(struct perf_counter *counter)
2624{
2625 perf_swcounter_update(counter);
2626}
2627
2628static int perf_swcounter_enable(struct perf_counter *counter)
2629{
2630 perf_swcounter_set_period(counter);
2631 return 0;
2632}
2633
2634static void perf_swcounter_disable(struct perf_counter *counter)
2635{
2636 perf_swcounter_update(counter);
2637}
2638
2639static const struct pmu perf_ops_generic = {
2640 .enable = perf_swcounter_enable,
2641 .disable = perf_swcounter_disable,
2642 .read = perf_swcounter_read,
2643};
2644
2645/*
2646 * Software counter: cpu wall time clock
2647 */
2648
2649static void cpu_clock_perf_counter_update(struct perf_counter *counter)
2650{
2651 int cpu = raw_smp_processor_id();
2652 s64 prev;
2653 u64 now;
2654
2655 now = cpu_clock(cpu);
2656 prev = atomic64_read(&counter->hw.prev_count);
2657 atomic64_set(&counter->hw.prev_count, now);
2658 atomic64_add(now - prev, &counter->count);
2659}
2660
2661static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
2662{
2663 struct hw_perf_counter *hwc = &counter->hw;
2664 int cpu = raw_smp_processor_id();
2665
2666 atomic64_set(&hwc->prev_count, cpu_clock(cpu));
2667 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2668 hwc->hrtimer.function = perf_swcounter_hrtimer;
2669 if (hwc->irq_period) {
2670 u64 period = max_t(u64, 10000, hwc->irq_period);
2671 __hrtimer_start_range_ns(&hwc->hrtimer,
2672 ns_to_ktime(period), 0,
2673 HRTIMER_MODE_REL, 0);
2674 }
2675
2676 return 0;
2677}
2678
2679static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
2680{
2681 hrtimer_cancel(&counter->hw.hrtimer);
2682 cpu_clock_perf_counter_update(counter);
2683}
2684
2685static void cpu_clock_perf_counter_read(struct perf_counter *counter)
2686{
2687 cpu_clock_perf_counter_update(counter);
2688}
2689
2690static const struct pmu perf_ops_cpu_clock = {
2691 .enable = cpu_clock_perf_counter_enable,
2692 .disable = cpu_clock_perf_counter_disable,
2693 .read = cpu_clock_perf_counter_read,
2694};
2695
2696/*
2697 * Software counter: task time clock
2698 */
2699
2700static void task_clock_perf_counter_update(struct perf_counter *counter, u64 now)
2701{
2702 u64 prev;
2703 s64 delta;
2704
2705 prev = atomic64_xchg(&counter->hw.prev_count, now);
2706 delta = now - prev;
2707 atomic64_add(delta, &counter->count);
2708}
2709
2710static int task_clock_perf_counter_enable(struct perf_counter *counter)
2711{
2712 struct hw_perf_counter *hwc = &counter->hw;
2713 u64 now;
2714
2715 now = counter->ctx->time;
2716
2717 atomic64_set(&hwc->prev_count, now);
2718 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
2719 hwc->hrtimer.function = perf_swcounter_hrtimer;
2720 if (hwc->irq_period) {
2721 u64 period = max_t(u64, 10000, hwc->irq_period);
2722 __hrtimer_start_range_ns(&hwc->hrtimer,
2723 ns_to_ktime(period), 0,
2724 HRTIMER_MODE_REL, 0);
2725 }
2726
2727 return 0;
2728}
2729
2730static void task_clock_perf_counter_disable(struct perf_counter *counter)
2731{
2732 hrtimer_cancel(&counter->hw.hrtimer);
2733 task_clock_perf_counter_update(counter, counter->ctx->time);
2734
2735}
2736
2737static void task_clock_perf_counter_read(struct perf_counter *counter)
2738{
2739 u64 time;
2740
2741 if (!in_nmi()) {
2742 update_context_time(counter->ctx);
2743 time = counter->ctx->time;
2744 } else {
2745 u64 now = perf_clock();
2746 u64 delta = now - counter->ctx->timestamp;
2747 time = counter->ctx->time + delta;
2748 }
2749
2750 task_clock_perf_counter_update(counter, time);
2751}
2752
2753static const struct pmu perf_ops_task_clock = {
2754 .enable = task_clock_perf_counter_enable,
2755 .disable = task_clock_perf_counter_disable,
2756 .read = task_clock_perf_counter_read,
2757};
2758
2759/*
2760 * Software counter: cpu migrations
2761 */
2762
2763static inline u64 get_cpu_migrations(struct perf_counter *counter)
2764{
2765 struct task_struct *curr = counter->ctx->task;
2766
2767 if (curr)
2768 return curr->se.nr_migrations;
2769 return cpu_nr_migrations(smp_processor_id());
2770}
2771
2772static void cpu_migrations_perf_counter_update(struct perf_counter *counter)
2773{
2774 u64 prev, now;
2775 s64 delta;
2776
2777 prev = atomic64_read(&counter->hw.prev_count);
2778 now = get_cpu_migrations(counter);
2779
2780 atomic64_set(&counter->hw.prev_count, now);
2781
2782 delta = now - prev;
2783
2784 atomic64_add(delta, &counter->count);
2785}
2786
2787static void cpu_migrations_perf_counter_read(struct perf_counter *counter)
2788{
2789 cpu_migrations_perf_counter_update(counter);
2790}
2791
2792static int cpu_migrations_perf_counter_enable(struct perf_counter *counter)
2793{
2794 if (counter->prev_state <= PERF_COUNTER_STATE_OFF)
2795 atomic64_set(&counter->hw.prev_count,
2796 get_cpu_migrations(counter));
2797 return 0;
2798}
2799
2800static void cpu_migrations_perf_counter_disable(struct perf_counter *counter)
2801{
2802 cpu_migrations_perf_counter_update(counter);
2803}
2804
2805static const struct pmu perf_ops_cpu_migrations = {
2806 .enable = cpu_migrations_perf_counter_enable,
2807 .disable = cpu_migrations_perf_counter_disable,
2808 .read = cpu_migrations_perf_counter_read,
2809};
2810
2811#ifdef CONFIG_EVENT_PROFILE
2812void perf_tpcounter_event(int event_id)
2813{
2814 struct pt_regs *regs = get_irq_regs();
2815
2816 if (!regs)
2817 regs = task_pt_regs(current);
2818
2819 __perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, 1, 1, regs, 0);
2820}
2821EXPORT_SYMBOL_GPL(perf_tpcounter_event);
2822
2823extern int ftrace_profile_enable(int);
2824extern void ftrace_profile_disable(int);
2825
2826static void tp_perf_counter_destroy(struct perf_counter *counter)
2827{
2828 ftrace_profile_disable(perf_event_id(&counter->hw_event));
2829}
2830
2831static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
2832{
2833 int event_id = perf_event_id(&counter->hw_event);
2834 int ret;
2835
2836 ret = ftrace_profile_enable(event_id);
2837 if (ret)
2838 return NULL;
2839
2840 counter->destroy = tp_perf_counter_destroy;
2841 counter->hw.irq_period = counter->hw_event.irq_period;
2842
2843 return &perf_ops_generic;
2844}
2845#else
2846static const struct pmu *tp_perf_counter_init(struct perf_counter *counter)
2847{
2848 return NULL;
2849}
2850#endif
2851
2852static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
2853{
2854 const struct pmu *pmu = NULL;
2855
2856 /*
2857 * Software counters (currently) can't in general distinguish
2858 * between user, kernel and hypervisor events.
2859 * However, context switches and cpu migrations are considered
2860 * to be kernel events, and page faults are never hypervisor
2861 * events.
2862 */
2863 switch (perf_event_id(&counter->hw_event)) {
2864 case PERF_COUNT_CPU_CLOCK:
2865 pmu = &perf_ops_cpu_clock;
2866
2867 break;
2868 case PERF_COUNT_TASK_CLOCK:
2869 /*
2870 * If the user instantiates this as a per-cpu counter,
2871 * use the cpu_clock counter instead.
2872 */
2873 if (counter->ctx->task)
2874 pmu = &perf_ops_task_clock;
2875 else
2876 pmu = &perf_ops_cpu_clock;
2877
2878 break;
2879 case PERF_COUNT_PAGE_FAULTS:
2880 case PERF_COUNT_PAGE_FAULTS_MIN:
2881 case PERF_COUNT_PAGE_FAULTS_MAJ:
2882 case PERF_COUNT_CONTEXT_SWITCHES:
2883 pmu = &perf_ops_generic;
2884 break;
2885 case PERF_COUNT_CPU_MIGRATIONS:
2886 if (!counter->hw_event.exclude_kernel)
2887 pmu = &perf_ops_cpu_migrations;
2888 break;
2889 }
2890
2891 return pmu;
2892}
2893
2894/*
2895 * Allocate and initialize a counter structure
2896 */
2897static struct perf_counter *
2898perf_counter_alloc(struct perf_counter_hw_event *hw_event,
2899 int cpu,
2900 struct perf_counter_context *ctx,
2901 struct perf_counter *group_leader,
2902 gfp_t gfpflags)
2903{
2904 const struct pmu *pmu;
2905 struct perf_counter *counter;
2906 struct hw_perf_counter *hwc;
2907 long err;
2908
2909 counter = kzalloc(sizeof(*counter), gfpflags);
2910 if (!counter)
2911 return ERR_PTR(-ENOMEM);
2912
2913 /*
2914 * Single counters are their own group leaders, with an
2915 * empty sibling list:
2916 */
2917 if (!group_leader)
2918 group_leader = counter;
2919
2920 mutex_init(&counter->mutex);
2921 INIT_LIST_HEAD(&counter->list_entry);
2922 INIT_LIST_HEAD(&counter->event_entry);
2923 INIT_LIST_HEAD(&counter->sibling_list);
2924 init_waitqueue_head(&counter->waitq);
2925
2926 mutex_init(&counter->mmap_mutex);
2927
2928 INIT_LIST_HEAD(&counter->child_list);
2929
2930 counter->cpu = cpu;
2931 counter->hw_event = *hw_event;
2932 counter->group_leader = group_leader;
2933 counter->pmu = NULL;
2934 counter->ctx = ctx;
2935
2936 counter->state = PERF_COUNTER_STATE_INACTIVE;
2937 if (hw_event->disabled)
2938 counter->state = PERF_COUNTER_STATE_OFF;
2939
2940 pmu = NULL;
2941
2942 hwc = &counter->hw;
2943 if (hw_event->freq && hw_event->irq_freq)
2944 hwc->irq_period = div64_u64(TICK_NSEC, hw_event->irq_freq);
2945 else
2946 hwc->irq_period = hw_event->irq_period;
2947
2948 /*
2949 * we currently do not support PERF_RECORD_GROUP on inherited counters
2950 */
2951 if (hw_event->inherit && (hw_event->record_type & PERF_RECORD_GROUP))
2952 goto done;
2953
2954 if (perf_event_raw(hw_event)) {
2955 pmu = hw_perf_counter_init(counter);
2956 goto done;
2957 }
2958
2959 switch (perf_event_type(hw_event)) {
2960 case PERF_TYPE_HARDWARE:
2961 pmu = hw_perf_counter_init(counter);
2962 break;
2963
2964 case PERF_TYPE_SOFTWARE:
2965 pmu = sw_perf_counter_init(counter);
2966 break;
2967
2968 case PERF_TYPE_TRACEPOINT:
2969 pmu = tp_perf_counter_init(counter);
2970 break;
2971 }
2972done:
2973 err = 0;
2974 if (!pmu)
2975 err = -EINVAL;
2976 else if (IS_ERR(pmu))
2977 err = PTR_ERR(pmu);
2978
2979 if (err) {
2980 kfree(counter);
2981 return ERR_PTR(err);
2982 }
2983
2984 counter->pmu = pmu;
2985
2986 atomic_inc(&nr_counters);
2987 if (counter->hw_event.mmap)
2988 atomic_inc(&nr_mmap_tracking);
2989 if (counter->hw_event.munmap)
2990 atomic_inc(&nr_munmap_tracking);
2991 if (counter->hw_event.comm)
2992 atomic_inc(&nr_comm_tracking);
2993
2994 return counter;
2995}
2996
2997/**
2998 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2999 *
3000 * @hw_event_uptr: event type attributes for monitoring/sampling
3001 * @pid: target pid
3002 * @cpu: target cpu
3003 * @group_fd: group leader counter fd
3004 */
3005SYSCALL_DEFINE5(perf_counter_open,
3006 const struct perf_counter_hw_event __user *, hw_event_uptr,
3007 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
3008{
3009 struct perf_counter *counter, *group_leader;
3010 struct perf_counter_hw_event hw_event;
3011 struct perf_counter_context *ctx;
3012 struct file *counter_file = NULL;
3013 struct file *group_file = NULL;
3014 int fput_needed = 0;
3015 int fput_needed2 = 0;
3016 int ret;
3017
3018 /* for future expandability... */
3019 if (flags)
3020 return -EINVAL;
3021
3022 if (copy_from_user(&hw_event, hw_event_uptr, sizeof(hw_event)) != 0)
3023 return -EFAULT;
3024
3025 /*
3026 * Get the target context (task or percpu):
3027 */
3028 ctx = find_get_context(pid, cpu);
3029 if (IS_ERR(ctx))
3030 return PTR_ERR(ctx);
3031
3032 /*
3033 * Look up the group leader (we will attach this counter to it):
3034 */
3035 group_leader = NULL;
3036 if (group_fd != -1) {
3037 ret = -EINVAL;
3038 group_file = fget_light(group_fd, &fput_needed);
3039 if (!group_file)
3040 goto err_put_context;
3041 if (group_file->f_op != &perf_fops)
3042 goto err_put_context;
3043
3044 group_leader = group_file->private_data;
3045 /*
3046 * Do not allow a recursive hierarchy (this new sibling
3047 * becoming part of another group-sibling):
3048 */
3049 if (group_leader->group_leader != group_leader)
3050 goto err_put_context;
3051 /*
3052 * Do not allow to attach to a group in a different
3053 * task or CPU context:
3054 */
3055 if (group_leader->ctx != ctx)
3056 goto err_put_context;
3057 /*
3058 * Only a group leader can be exclusive or pinned
3059 */
3060 if (hw_event.exclusive || hw_event.pinned)
3061 goto err_put_context;
3062 }
3063
3064 counter = perf_counter_alloc(&hw_event, cpu, ctx, group_leader,
3065 GFP_KERNEL);
3066 ret = PTR_ERR(counter);
3067 if (IS_ERR(counter))
3068 goto err_put_context;
3069
3070 ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0);
3071 if (ret < 0)
3072 goto err_free_put_context;
3073
3074 counter_file = fget_light(ret, &fput_needed2);
3075 if (!counter_file)
3076 goto err_free_put_context;
3077
3078 counter->filp = counter_file;
3079 mutex_lock(&ctx->mutex);
3080 perf_install_in_context(ctx, counter, cpu);
3081 mutex_unlock(&ctx->mutex);
3082
3083 fput_light(counter_file, fput_needed2);
3084
3085out_fput:
3086 fput_light(group_file, fput_needed);
3087
3088 return ret;
3089
3090err_free_put_context:
3091 kfree(counter);
3092
3093err_put_context:
3094 put_context(ctx);
3095
3096 goto out_fput;
3097}
3098
3099/*
3100 * Initialize the perf_counter context in a task_struct:
3101 */
3102static void
3103__perf_counter_init_context(struct perf_counter_context *ctx,
3104 struct task_struct *task)
3105{
3106 memset(ctx, 0, sizeof(*ctx));
3107 spin_lock_init(&ctx->lock);
3108 mutex_init(&ctx->mutex);
3109 INIT_LIST_HEAD(&ctx->counter_list);
3110 INIT_LIST_HEAD(&ctx->event_list);
3111 ctx->task = task;
3112}
3113
3114/*
3115 * inherit a counter from parent task to child task:
3116 */
3117static struct perf_counter *
3118inherit_counter(struct perf_counter *parent_counter,
3119 struct task_struct *parent,
3120 struct perf_counter_context *parent_ctx,
3121 struct task_struct *child,
3122 struct perf_counter *group_leader,
3123 struct perf_counter_context *child_ctx)
3124{
3125 struct perf_counter *child_counter;
3126
3127 /*
3128 * Instead of creating recursive hierarchies of counters,
3129 * we link inherited counters back to the original parent,
3130 * which has a filp for sure, which we use as the reference
3131 * count:
3132 */
3133 if (parent_counter->parent)
3134 parent_counter = parent_counter->parent;
3135
3136 child_counter = perf_counter_alloc(&parent_counter->hw_event,
3137 parent_counter->cpu, child_ctx,
3138 group_leader, GFP_KERNEL);
3139 if (IS_ERR(child_counter))
3140 return child_counter;
3141
3142 /*
3143 * Link it up in the child's context:
3144 */
3145 child_counter->task = child;
3146 add_counter_to_ctx(child_counter, child_ctx);
3147
3148 child_counter->parent = parent_counter;
3149 /*
3150 * inherit into child's child as well:
3151 */
3152 child_counter->hw_event.inherit = 1;
3153
3154 /*
3155 * Get a reference to the parent filp - we will fput it
3156 * when the child counter exits. This is safe to do because
3157 * we are in the parent and we know that the filp still
3158 * exists and has a nonzero count:
3159 */
3160 atomic_long_inc(&parent_counter->filp->f_count);
3161
3162 /*
3163 * Link this into the parent counter's child list
3164 */
3165 mutex_lock(&parent_counter->mutex);
3166 list_add_tail(&child_counter->child_list, &parent_counter->child_list);
3167
3168 /*
3169 * Make the child state follow the state of the parent counter,
3170 * not its hw_event.disabled bit. We hold the parent's mutex,
3171 * so we won't race with perf_counter_{en,dis}able_family.
3172 */
3173 if (parent_counter->state >= PERF_COUNTER_STATE_INACTIVE)
3174 child_counter->state = PERF_COUNTER_STATE_INACTIVE;
3175 else
3176 child_counter->state = PERF_COUNTER_STATE_OFF;
3177
3178 mutex_unlock(&parent_counter->mutex);
3179
3180 return child_counter;
3181}
3182
3183static int inherit_group(struct perf_counter *parent_counter,
3184 struct task_struct *parent,
3185 struct perf_counter_context *parent_ctx,
3186 struct task_struct *child,
3187 struct perf_counter_context *child_ctx)
3188{
3189 struct perf_counter *leader;
3190 struct perf_counter *sub;
3191 struct perf_counter *child_ctr;
3192
3193 leader = inherit_counter(parent_counter, parent, parent_ctx,
3194 child, NULL, child_ctx);
3195 if (IS_ERR(leader))
3196 return PTR_ERR(leader);
3197 list_for_each_entry(sub, &parent_counter->sibling_list, list_entry) {
3198 child_ctr = inherit_counter(sub, parent, parent_ctx,
3199 child, leader, child_ctx);
3200 if (IS_ERR(child_ctr))
3201 return PTR_ERR(child_ctr);
3202 }
3203 return 0;
3204}
3205
3206static void sync_child_counter(struct perf_counter *child_counter,
3207 struct perf_counter *parent_counter)
3208{
3209 u64 child_val;
3210
3211 child_val = atomic64_read(&child_counter->count);
3212
3213 /*
3214 * Add back the child's count to the parent's count:
3215 */
3216 atomic64_add(child_val, &parent_counter->count);
3217 atomic64_add(child_counter->total_time_enabled,
3218 &parent_counter->child_total_time_enabled);
3219 atomic64_add(child_counter->total_time_running,
3220 &parent_counter->child_total_time_running);
3221
3222 /*
3223 * Remove this counter from the parent's list
3224 */
3225 mutex_lock(&parent_counter->mutex);
3226 list_del_init(&child_counter->child_list);
3227 mutex_unlock(&parent_counter->mutex);
3228
3229 /*
3230 * Release the parent counter, if this was the last
3231 * reference to it.
3232 */
3233 fput(parent_counter->filp);
3234}
3235
3236static void
3237__perf_counter_exit_task(struct task_struct *child,
3238 struct perf_counter *child_counter,
3239 struct perf_counter_context *child_ctx)
3240{
3241 struct perf_counter *parent_counter;
3242
3243 /*
3244 * If we do not self-reap then we have to wait for the
3245 * child task to unschedule (it will happen for sure),
3246 * so that its counter is at its final count. (This
3247 * condition triggers rarely - child tasks usually get
3248 * off their CPU before the parent has a chance to
3249 * get this far into the reaping action)
3250 */
3251 if (child != current) {
3252 wait_task_inactive(child, 0);
3253 update_counter_times(child_counter);
3254 list_del_counter(child_counter, child_ctx);
3255 } else {
3256 struct perf_cpu_context *cpuctx;
3257 unsigned long flags;
3258
3259 /*
3260 * Disable and unlink this counter.
3261 *
3262 * Be careful about zapping the list - IRQ/NMI context
3263 * could still be processing it:
3264 */
3265 local_irq_save(flags);
3266 perf_disable();
3267
3268 cpuctx = &__get_cpu_var(perf_cpu_context);
3269
3270 group_sched_out(child_counter, cpuctx, child_ctx);
3271 update_counter_times(child_counter);
3272
3273 list_del_counter(child_counter, child_ctx);
3274
3275 perf_enable();
3276 local_irq_restore(flags);
3277 }
3278
3279 parent_counter = child_counter->parent;
3280 /*
3281 * It can happen that parent exits first, and has counters
3282 * that are still around due to the child reference. These
3283 * counters need to be zapped - but otherwise linger.
3284 */
3285 if (parent_counter) {
3286 sync_child_counter(child_counter, parent_counter);
3287 free_counter(child_counter);
3288 }
3289}
3290
3291/*
3292 * When a child task exits, feed back counter values to parent counters.
3293 *
3294 * Note: we may be running in child context, but the PID is not hashed
3295 * anymore so new counters will not be added.
3296 */
3297void perf_counter_exit_task(struct task_struct *child)
3298{
3299 struct perf_counter *child_counter, *tmp;
3300 struct perf_counter_context *child_ctx;
3301
3302 child_ctx = &child->perf_counter_ctx;
3303
3304 if (likely(!child_ctx->nr_counters))
3305 return;
3306
3307again:
3308 list_for_each_entry_safe(child_counter, tmp, &child_ctx->counter_list,
3309 list_entry)
3310 __perf_counter_exit_task(child, child_counter, child_ctx);
3311
3312 /*
3313 * If the last counter was a group counter, it will have appended all
3314 * its siblings to the list, but we obtained 'tmp' before that which
3315 * will still point to the list head terminating the iteration.
3316 */
3317 if (!list_empty(&child_ctx->counter_list))
3318 goto again;
3319}
3320
3321/*
3322 * Initialize the perf_counter context in task_struct
3323 */
3324void perf_counter_init_task(struct task_struct *child)
3325{
3326 struct perf_counter_context *child_ctx, *parent_ctx;
3327 struct perf_counter *counter;
3328 struct task_struct *parent = current;
3329
3330 child_ctx = &child->perf_counter_ctx;
3331 parent_ctx = &parent->perf_counter_ctx;
3332
3333 __perf_counter_init_context(child_ctx, child);
3334
3335 /*
3336 * This is executed from the parent task context, so inherit
3337 * counters that have been marked for cloning:
3338 */
3339
3340 if (likely(!parent_ctx->nr_counters))
3341 return;
3342
3343 /*
3344 * Lock the parent list. No need to lock the child - not PID
3345 * hashed yet and not running, so nobody can access it.
3346 */
3347 mutex_lock(&parent_ctx->mutex);
3348
3349 /*
3350 * We dont have to disable NMIs - we are only looking at
3351 * the list, not manipulating it:
3352 */
3353 list_for_each_entry(counter, &parent_ctx->counter_list, list_entry) {
3354 if (!counter->hw_event.inherit)
3355 continue;
3356
3357 if (inherit_group(counter, parent,
3358 parent_ctx, child, child_ctx))
3359 break;
3360 }
3361
3362 mutex_unlock(&parent_ctx->mutex);
3363}
3364
3365static void __cpuinit perf_counter_init_cpu(int cpu)
3366{
3367 struct perf_cpu_context *cpuctx;
3368
3369 cpuctx = &per_cpu(perf_cpu_context, cpu);
3370 __perf_counter_init_context(&cpuctx->ctx, NULL);
3371
3372 spin_lock(&perf_resource_lock);
3373 cpuctx->max_pertask = perf_max_counters - perf_reserved_percpu;
3374 spin_unlock(&perf_resource_lock);
3375
3376 hw_perf_counter_setup(cpu);
3377}
3378
3379#ifdef CONFIG_HOTPLUG_CPU
3380static void __perf_counter_exit_cpu(void *info)
3381{
3382 struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context);
3383 struct perf_counter_context *ctx = &cpuctx->ctx;
3384 struct perf_counter *counter, *tmp;
3385
3386 list_for_each_entry_safe(counter, tmp, &ctx->counter_list, list_entry)
3387 __perf_counter_remove_from_context(counter);
3388}
3389static void perf_counter_exit_cpu(int cpu)
3390{
3391 struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu);
3392 struct perf_counter_context *ctx = &cpuctx->ctx;
3393
3394 mutex_lock(&ctx->mutex);
3395 smp_call_function_single(cpu, __perf_counter_exit_cpu, NULL, 1);
3396 mutex_unlock(&ctx->mutex);
3397}
3398#else
3399static inline void perf_counter_exit_cpu(int cpu) { }
3400#endif
3401
3402static int __cpuinit
3403perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
3404{
3405 unsigned int cpu = (long)hcpu;
3406
3407 switch (action) {
3408
3409 case CPU_UP_PREPARE:
3410 case CPU_UP_PREPARE_FROZEN:
3411 perf_counter_init_cpu(cpu);
3412 break;
3413
3414 case CPU_DOWN_PREPARE:
3415 case CPU_DOWN_PREPARE_FROZEN:
3416 perf_counter_exit_cpu(cpu);
3417 break;
3418
3419 default:
3420 break;
3421 }
3422
3423 return NOTIFY_OK;
3424}
3425
3426static struct notifier_block __cpuinitdata perf_cpu_nb = {
3427 .notifier_call = perf_cpu_notify,
3428};
3429
3430void __init perf_counter_init(void)
3431{
3432 perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
3433 (void *)(long)smp_processor_id());
3434 register_cpu_notifier(&perf_cpu_nb);
3435}
3436
3437static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, char *buf)
3438{
3439 return sprintf(buf, "%d\n", perf_reserved_percpu);
3440}
3441
3442static ssize_t
3443perf_set_reserve_percpu(struct sysdev_class *class,
3444 const char *buf,
3445 size_t count)
3446{
3447 struct perf_cpu_context *cpuctx;
3448 unsigned long val;
3449 int err, cpu, mpt;
3450
3451 err = strict_strtoul(buf, 10, &val);
3452 if (err)
3453 return err;
3454 if (val > perf_max_counters)
3455 return -EINVAL;
3456
3457 spin_lock(&perf_resource_lock);
3458 perf_reserved_percpu = val;
3459 for_each_online_cpu(cpu) {
3460 cpuctx = &per_cpu(perf_cpu_context, cpu);
3461 spin_lock_irq(&cpuctx->ctx.lock);
3462 mpt = min(perf_max_counters - cpuctx->ctx.nr_counters,
3463 perf_max_counters - perf_reserved_percpu);
3464 cpuctx->max_pertask = mpt;
3465 spin_unlock_irq(&cpuctx->ctx.lock);
3466 }
3467 spin_unlock(&perf_resource_lock);
3468
3469 return count;
3470}
3471
3472static ssize_t perf_show_overcommit(struct sysdev_class *class, char *buf)
3473{
3474 return sprintf(buf, "%d\n", perf_overcommit);
3475}
3476
3477static ssize_t
3478perf_set_overcommit(struct sysdev_class *class, const char *buf, size_t count)
3479{
3480 unsigned long val;
3481 int err;
3482
3483 err = strict_strtoul(buf, 10, &val);
3484 if (err)
3485 return err;
3486 if (val > 1)
3487 return -EINVAL;
3488
3489 spin_lock(&perf_resource_lock);
3490 perf_overcommit = val;
3491 spin_unlock(&perf_resource_lock);
3492
3493 return count;
3494}
3495
3496static SYSDEV_CLASS_ATTR(
3497 reserve_percpu,
3498 0644,
3499 perf_show_reserve_percpu,
3500 perf_set_reserve_percpu
3501 );
3502
3503static SYSDEV_CLASS_ATTR(
3504 overcommit,
3505 0644,
3506 perf_show_overcommit,
3507 perf_set_overcommit
3508 );
3509
3510static struct attribute *perfclass_attrs[] = {
3511 &attr_reserve_percpu.attr,
3512 &attr_overcommit.attr,
3513 NULL
3514};
3515
3516static struct attribute_group perfclass_attr_group = {
3517 .attrs = perfclass_attrs,
3518 .name = "perf_counters",
3519};
3520
3521static int __init perf_counter_sysfs_init(void)
3522{
3523 return sysfs_create_group(&cpu_sysdev_class.kset.kobj,
3524 &perfclass_attr_group);
3525}
3526device_initcall(perf_counter_sysfs_init);
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-19 12:13:40 -0500