core.c 209.6 KB
Newer Older
T
Thomas Gleixner 已提交
1
/*
I
Ingo Molnar 已提交
2
 * Performance events core code:
T
Thomas Gleixner 已提交
3
 *
4
 *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 6
 *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
 *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
A
Al Viro 已提交
7
 *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
8
 *
I
Ingo Molnar 已提交
9
 * For licensing details see kernel-base/COPYING
T
Thomas Gleixner 已提交
10 11 12
 */

#include <linux/fs.h>
13
#include <linux/mm.h>
T
Thomas Gleixner 已提交
14 15
#include <linux/cpu.h>
#include <linux/smp.h>
P
Peter Zijlstra 已提交
16
#include <linux/idr.h>
17
#include <linux/file.h>
T
Thomas Gleixner 已提交
18
#include <linux/poll.h>
19
#include <linux/slab.h>
20
#include <linux/hash.h>
21
#include <linux/tick.h>
T
Thomas Gleixner 已提交
22
#include <linux/sysfs.h>
23
#include <linux/dcache.h>
T
Thomas Gleixner 已提交
24
#include <linux/percpu.h>
25
#include <linux/ptrace.h>
P
Peter Zijlstra 已提交
26
#include <linux/reboot.h>
27
#include <linux/vmstat.h>
P
Peter Zijlstra 已提交
28
#include <linux/device.h>
29
#include <linux/export.h>
30
#include <linux/vmalloc.h>
31 32
#include <linux/hardirq.h>
#include <linux/rculist.h>
T
Thomas Gleixner 已提交
33 34 35
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/anon_inodes.h>
I
Ingo Molnar 已提交
36
#include <linux/kernel_stat.h>
37
#include <linux/cgroup.h>
38
#include <linux/perf_event.h>
L
Li Zefan 已提交
39
#include <linux/ftrace_event.h>
40
#include <linux/hw_breakpoint.h>
41
#include <linux/mm_types.h>
42
#include <linux/module.h>
43
#include <linux/mman.h>
P
Pawel Moll 已提交
44
#include <linux/compat.h>
45 46
#include <linux/bpf.h>
#include <linux/filter.h>
T
Thomas Gleixner 已提交
47

48 49
#include "internal.h"

50 51
#include <asm/irq_regs.h>

52 53
static struct workqueue_struct *perf_wq;

54
struct remote_function_call {
55 56 57 58
	struct task_struct	*p;
	int			(*func)(void *info);
	void			*info;
	int			ret;
59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91
};

static void remote_function(void *data)
{
	struct remote_function_call *tfc = data;
	struct task_struct *p = tfc->p;

	if (p) {
		tfc->ret = -EAGAIN;
		if (task_cpu(p) != smp_processor_id() || !task_curr(p))
			return;
	}

	tfc->ret = tfc->func(tfc->info);
}

/**
 * task_function_call - call a function on the cpu on which a task runs
 * @p:		the task to evaluate
 * @func:	the function to be called
 * @info:	the function call argument
 *
 * Calls the function @func when the task is currently running. This might
 * be on the current CPU, which just calls the function directly
 *
 * returns: @func return value, or
 *	    -ESRCH  - when the process isn't running
 *	    -EAGAIN - when the process moved away
 */
static int
task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
{
	struct remote_function_call data = {
92 93 94 95
		.p	= p,
		.func	= func,
		.info	= info,
		.ret	= -ESRCH, /* No such (running) process */
96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115
	};

	if (task_curr(p))
		smp_call_function_single(task_cpu(p), remote_function, &data, 1);

	return data.ret;
}

/**
 * cpu_function_call - call a function on the cpu
 * @func:	the function to be called
 * @info:	the function call argument
 *
 * Calls the function @func on the remote cpu.
 *
 * returns: @func return value or -ENXIO when the cpu is offline
 */
static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
{
	struct remote_function_call data = {
116 117 118 119
		.p	= NULL,
		.func	= func,
		.info	= info,
		.ret	= -ENXIO, /* No such CPU */
120 121 122 123 124 125 126
	};

	smp_call_function_single(cpu, remote_function, &data, 1);

	return data.ret;
}

127 128 129 130 131 132 133
#define EVENT_OWNER_KERNEL ((void *) -1)

static bool is_kernel_event(struct perf_event *event)
{
	return event->owner == EVENT_OWNER_KERNEL;
}

S
Stephane Eranian 已提交
134 135
#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
		       PERF_FLAG_FD_OUTPUT  |\
136 137
		       PERF_FLAG_PID_CGROUP |\
		       PERF_FLAG_FD_CLOEXEC)
S
Stephane Eranian 已提交
138

139 140 141 142 143 144 145
/*
 * branch priv levels that need permission checks
 */
#define PERF_SAMPLE_BRANCH_PERM_PLM \
	(PERF_SAMPLE_BRANCH_KERNEL |\
	 PERF_SAMPLE_BRANCH_HV)

146 147 148 149 150 151
enum event_type_t {
	EVENT_FLEXIBLE = 0x1,
	EVENT_PINNED = 0x2,
	EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
};

S
Stephane Eranian 已提交
152 153 154 155
/*
 * perf_sched_events : >0 events exist
 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
 */
156
struct static_key_deferred perf_sched_events __read_mostly;
S
Stephane Eranian 已提交
157
static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
158
static DEFINE_PER_CPU(int, perf_sched_cb_usages);
S
Stephane Eranian 已提交
159

160 161 162
static atomic_t nr_mmap_events __read_mostly;
static atomic_t nr_comm_events __read_mostly;
static atomic_t nr_task_events __read_mostly;
163
static atomic_t nr_freq_events __read_mostly;
164

P
Peter Zijlstra 已提交
165 166 167 168
static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
static struct srcu_struct pmus_srcu;

169
/*
170
 * perf event paranoia level:
171 172
 *  -1 - not paranoid at all
 *   0 - disallow raw tracepoint access for unpriv
173
 *   1 - disallow cpu events for unpriv
174
 *   2 - disallow kernel profiling for unpriv
175
 */
176
int sysctl_perf_event_paranoid __read_mostly = 1;
177

178 179
/* Minimum for 512 kiB + 1 user control page */
int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
180 181

/*
182
 * max perf event sample rate
183
 */
184 185 186 187 188 189 190 191 192
#define DEFAULT_MAX_SAMPLE_RATE		100000
#define DEFAULT_SAMPLE_PERIOD_NS	(NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
#define DEFAULT_CPU_TIME_MAX_PERCENT	25

int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;

static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;

P
Peter Zijlstra 已提交
193 194
static int perf_sample_allowed_ns __read_mostly =
	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
195 196 197 198 199 200

void update_perf_cpu_limits(void)
{
	u64 tmp = perf_sample_period_ns;

	tmp *= sysctl_perf_cpu_time_max_percent;
201
	do_div(tmp, 100);
P
Peter Zijlstra 已提交
202
	ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
203
}
P
Peter Zijlstra 已提交
204

205 206
static int perf_rotate_context(struct perf_cpu_context *cpuctx);

P
Peter Zijlstra 已提交
207 208 209 210
int perf_proc_update_handler(struct ctl_table *table, int write,
		void __user *buffer, size_t *lenp,
		loff_t *ppos)
{
211
	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
P
Peter Zijlstra 已提交
212 213 214 215 216

	if (ret || !write)
		return ret;

	max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234
	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
	update_perf_cpu_limits();

	return 0;
}

int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;

int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
				void __user *buffer, size_t *lenp,
				loff_t *ppos)
{
	int ret = proc_dointvec(table, write, buffer, lenp, ppos);

	if (ret || !write)
		return ret;

	update_perf_cpu_limits();
P
Peter Zijlstra 已提交
235 236 237

	return 0;
}
238

239 240 241 242 243 244 245
/*
 * perf samples are done in some very critical code paths (NMIs).
 * If they take too much CPU time, the system can lock up and not
 * get any real work done.  This will drop the sample rate when
 * we detect that events are taking too long.
 */
#define NR_ACCUMULATED_SAMPLES 128
P
Peter Zijlstra 已提交
246
static DEFINE_PER_CPU(u64, running_sample_length);
247

248
static void perf_duration_warn(struct irq_work *w)
249
{
250
	u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
251
	u64 avg_local_sample_len;
252
	u64 local_samples_len;
253

254
	local_samples_len = __this_cpu_read(running_sample_length);
255 256 257 258 259
	avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;

	printk_ratelimited(KERN_WARNING
			"perf interrupt took too long (%lld > %lld), lowering "
			"kernel.perf_event_max_sample_rate to %d\n",
260
			avg_local_sample_len, allowed_ns >> 1,
261 262 263 264 265 266 267
			sysctl_perf_event_sample_rate);
}

static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);

void perf_sample_event_took(u64 sample_len_ns)
{
P
Peter Zijlstra 已提交
268
	u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
269 270
	u64 avg_local_sample_len;
	u64 local_samples_len;
271

P
Peter Zijlstra 已提交
272
	if (allowed_ns == 0)
273 274 275
		return;

	/* decay the counter by 1 average sample */
276
	local_samples_len = __this_cpu_read(running_sample_length);
277 278
	local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
	local_samples_len += sample_len_ns;
279
	__this_cpu_write(running_sample_length, local_samples_len);
280 281 282 283 284 285 286 287

	/*
	 * note: this will be biased artifically low until we have
	 * seen NR_ACCUMULATED_SAMPLES.  Doing it this way keeps us
	 * from having to maintain a count.
	 */
	avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;

P
Peter Zijlstra 已提交
288
	if (avg_local_sample_len <= allowed_ns)
289 290 291 292 293 294 295 296 297 298
		return;

	if (max_samples_per_tick <= 1)
		return;

	max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
	sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;

	update_perf_cpu_limits();
299

300 301 302 303 304 305
	if (!irq_work_queue(&perf_duration_work)) {
		early_printk("perf interrupt took too long (%lld > %lld), lowering "
			     "kernel.perf_event_max_sample_rate to %d\n",
			     avg_local_sample_len, allowed_ns >> 1,
			     sysctl_perf_event_sample_rate);
	}
306 307
}

308
static atomic64_t perf_event_id;
309

310 311 312 313
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
			      enum event_type_t event_type);

static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
314 315 316 317 318
			     enum event_type_t event_type,
			     struct task_struct *task);

static void update_context_time(struct perf_event_context *ctx);
static u64 perf_event_time(struct perf_event *event);
319

320
void __weak perf_event_print_debug(void)	{ }
T
Thomas Gleixner 已提交
321

322
extern __weak const char *perf_pmu_name(void)
T
Thomas Gleixner 已提交
323
{
324
	return "pmu";
T
Thomas Gleixner 已提交
325 326
}

327 328 329 330 331
static inline u64 perf_clock(void)
{
	return local_clock();
}

332 333 334 335 336
static inline u64 perf_event_clock(struct perf_event *event)
{
	return event->clock();
}

S
Stephane Eranian 已提交
337 338 339 340 341 342
static inline struct perf_cpu_context *
__get_cpu_context(struct perf_event_context *ctx)
{
	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
}

343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358
static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
			  struct perf_event_context *ctx)
{
	raw_spin_lock(&cpuctx->ctx.lock);
	if (ctx)
		raw_spin_lock(&ctx->lock);
}

static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
			    struct perf_event_context *ctx)
{
	if (ctx)
		raw_spin_unlock(&ctx->lock);
	raw_spin_unlock(&cpuctx->ctx.lock);
}

S
Stephane Eranian 已提交
359 360 361 362 363 364 365 366
#ifdef CONFIG_CGROUP_PERF

static inline bool
perf_cgroup_match(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);

367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382
	/* @event doesn't care about cgroup */
	if (!event->cgrp)
		return true;

	/* wants specific cgroup scope but @cpuctx isn't associated with any */
	if (!cpuctx->cgrp)
		return false;

	/*
	 * Cgroup scoping is recursive.  An event enabled for a cgroup is
	 * also enabled for all its descendant cgroups.  If @cpuctx's
	 * cgroup is a descendant of @event's (the test covers identity
	 * case), it's a match.
	 */
	return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
				    event->cgrp->css.cgroup);
S
Stephane Eranian 已提交
383 384 385 386
}

static inline void perf_detach_cgroup(struct perf_event *event)
{
Z
Zefan Li 已提交
387
	css_put(&event->cgrp->css);
S
Stephane Eranian 已提交
388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425
	event->cgrp = NULL;
}

static inline int is_cgroup_event(struct perf_event *event)
{
	return event->cgrp != NULL;
}

static inline u64 perf_cgroup_event_time(struct perf_event *event)
{
	struct perf_cgroup_info *t;

	t = per_cpu_ptr(event->cgrp->info, event->cpu);
	return t->time;
}

static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
{
	struct perf_cgroup_info *info;
	u64 now;

	now = perf_clock();

	info = this_cpu_ptr(cgrp->info);

	info->time += now - info->timestamp;
	info->timestamp = now;
}

static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
{
	struct perf_cgroup *cgrp_out = cpuctx->cgrp;
	if (cgrp_out)
		__update_cgrp_time(cgrp_out);
}

static inline void update_cgrp_time_from_event(struct perf_event *event)
{
426 427
	struct perf_cgroup *cgrp;

S
Stephane Eranian 已提交
428
	/*
429 430
	 * ensure we access cgroup data only when needed and
	 * when we know the cgroup is pinned (css_get)
S
Stephane Eranian 已提交
431
	 */
432
	if (!is_cgroup_event(event))
S
Stephane Eranian 已提交
433 434
		return;

435 436 437 438 439 440
	cgrp = perf_cgroup_from_task(current);
	/*
	 * Do not update time when cgroup is not active
	 */
	if (cgrp == event->cgrp)
		__update_cgrp_time(event->cgrp);
S
Stephane Eranian 已提交
441 442 443
}

static inline void
444 445
perf_cgroup_set_timestamp(struct task_struct *task,
			  struct perf_event_context *ctx)
S
Stephane Eranian 已提交
446 447 448 449
{
	struct perf_cgroup *cgrp;
	struct perf_cgroup_info *info;

450 451 452 453 454 455
	/*
	 * ctx->lock held by caller
	 * ensure we do not access cgroup data
	 * unless we have the cgroup pinned (css_get)
	 */
	if (!task || !ctx->nr_cgroups)
S
Stephane Eranian 已提交
456 457 458 459
		return;

	cgrp = perf_cgroup_from_task(task);
	info = this_cpu_ptr(cgrp->info);
460
	info->timestamp = ctx->timestamp;
S
Stephane Eranian 已提交
461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492
}

#define PERF_CGROUP_SWOUT	0x1 /* cgroup switch out every event */
#define PERF_CGROUP_SWIN	0x2 /* cgroup switch in events based on task */

/*
 * reschedule events based on the cgroup constraint of task.
 *
 * mode SWOUT : schedule out everything
 * mode SWIN : schedule in based on cgroup for next
 */
void perf_cgroup_switch(struct task_struct *task, int mode)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	/*
	 * disable interrupts to avoid geting nr_cgroup
	 * changes via __perf_event_disable(). Also
	 * avoids preemption.
	 */
	local_irq_save(flags);

	/*
	 * we reschedule only in the presence of cgroup
	 * constrained events.
	 */
	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
493 494
		if (cpuctx->unique_pmu != pmu)
			continue; /* ensure we process each cpuctx once */
S
Stephane Eranian 已提交
495 496 497 498 499 500 501 502 503

		/*
		 * perf_cgroup_events says at least one
		 * context on this CPU has cgroup events.
		 *
		 * ctx->nr_cgroups reports the number of cgroup
		 * events for a context.
		 */
		if (cpuctx->ctx.nr_cgroups > 0) {
504 505
			perf_ctx_lock(cpuctx, cpuctx->task_ctx);
			perf_pmu_disable(cpuctx->ctx.pmu);
S
Stephane Eranian 已提交
506 507 508 509 510 511 512 513 514 515 516

			if (mode & PERF_CGROUP_SWOUT) {
				cpu_ctx_sched_out(cpuctx, EVENT_ALL);
				/*
				 * must not be done before ctxswout due
				 * to event_filter_match() in event_sched_out()
				 */
				cpuctx->cgrp = NULL;
			}

			if (mode & PERF_CGROUP_SWIN) {
517
				WARN_ON_ONCE(cpuctx->cgrp);
518 519 520 521
				/*
				 * set cgrp before ctxsw in to allow
				 * event_filter_match() to not have to pass
				 * task around
S
Stephane Eranian 已提交
522 523 524 525
				 */
				cpuctx->cgrp = perf_cgroup_from_task(task);
				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
			}
526 527
			perf_pmu_enable(cpuctx->ctx.pmu);
			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
S
Stephane Eranian 已提交
528 529 530 531 532 533 534 535
		}
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

536 537
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
S
Stephane Eranian 已提交
538
{
539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

	/*
	 * we come here when we know perf_cgroup_events > 0
	 */
	cgrp1 = perf_cgroup_from_task(task);

	/*
	 * next is NULL when called from perf_event_enable_on_exec()
	 * that will systematically cause a cgroup_switch()
	 */
	if (next)
		cgrp2 = perf_cgroup_from_task(next);

	/*
	 * only schedule out current cgroup events if we know
	 * that we are switching to a different cgroup. Otherwise,
	 * do no touch the cgroup events.
	 */
	if (cgrp1 != cgrp2)
		perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
S
Stephane Eranian 已提交
561 562
}

563 564
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
S
Stephane Eranian 已提交
565
{
566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583
	struct perf_cgroup *cgrp1;
	struct perf_cgroup *cgrp2 = NULL;

	/*
	 * we come here when we know perf_cgroup_events > 0
	 */
	cgrp1 = perf_cgroup_from_task(task);

	/* prev can never be NULL */
	cgrp2 = perf_cgroup_from_task(prev);

	/*
	 * only need to schedule in cgroup events if we are changing
	 * cgroup during ctxsw. Cgroup events were not scheduled
	 * out of ctxsw out if that was not the case.
	 */
	if (cgrp1 != cgrp2)
		perf_cgroup_switch(task, PERF_CGROUP_SWIN);
S
Stephane Eranian 已提交
584 585 586 587 588 589 590 591
}

static inline int perf_cgroup_connect(int fd, struct perf_event *event,
				      struct perf_event_attr *attr,
				      struct perf_event *group_leader)
{
	struct perf_cgroup *cgrp;
	struct cgroup_subsys_state *css;
592 593
	struct fd f = fdget(fd);
	int ret = 0;
S
Stephane Eranian 已提交
594

595
	if (!f.file)
S
Stephane Eranian 已提交
596 597
		return -EBADF;

A
Al Viro 已提交
598
	css = css_tryget_online_from_dir(f.file->f_path.dentry,
599
					 &perf_event_cgrp_subsys);
600 601 602 603
	if (IS_ERR(css)) {
		ret = PTR_ERR(css);
		goto out;
	}
S
Stephane Eranian 已提交
604 605 606 607 608 609 610 611 612 613 614 615 616

	cgrp = container_of(css, struct perf_cgroup, css);
	event->cgrp = cgrp;

	/*
	 * all events in a group must monitor
	 * the same cgroup because a task belongs
	 * to only one perf cgroup at a time
	 */
	if (group_leader && group_leader->cgrp != cgrp) {
		perf_detach_cgroup(event);
		ret = -EINVAL;
	}
617
out:
618
	fdput(f);
S
Stephane Eranian 已提交
619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691
	return ret;
}

static inline void
perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
{
	struct perf_cgroup_info *t;
	t = per_cpu_ptr(event->cgrp->info, event->cpu);
	event->shadow_ctx_time = now - t->timestamp;
}

static inline void
perf_cgroup_defer_enabled(struct perf_event *event)
{
	/*
	 * when the current task's perf cgroup does not match
	 * the event's, we need to remember to call the
	 * perf_mark_enable() function the first time a task with
	 * a matching perf cgroup is scheduled in.
	 */
	if (is_cgroup_event(event) && !perf_cgroup_match(event))
		event->cgrp_defer_enabled = 1;
}

static inline void
perf_cgroup_mark_enabled(struct perf_event *event,
			 struct perf_event_context *ctx)
{
	struct perf_event *sub;
	u64 tstamp = perf_event_time(event);

	if (!event->cgrp_defer_enabled)
		return;

	event->cgrp_defer_enabled = 0;

	event->tstamp_enabled = tstamp - event->total_time_enabled;
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
		if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
			sub->cgrp_defer_enabled = 0;
		}
	}
}
#else /* !CONFIG_CGROUP_PERF */

static inline bool
perf_cgroup_match(struct perf_event *event)
{
	return true;
}

static inline void perf_detach_cgroup(struct perf_event *event)
{}

static inline int is_cgroup_event(struct perf_event *event)
{
	return 0;
}

static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
{
	return 0;
}

static inline void update_cgrp_time_from_event(struct perf_event *event)
{
}

static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
{
}

692 693
static inline void perf_cgroup_sched_out(struct task_struct *task,
					 struct task_struct *next)
S
Stephane Eranian 已提交
694 695 696
{
}

697 698
static inline void perf_cgroup_sched_in(struct task_struct *prev,
					struct task_struct *task)
S
Stephane Eranian 已提交
699 700 701 702 703 704 705 706 707 708 709
{
}

static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
				      struct perf_event_attr *attr,
				      struct perf_event *group_leader)
{
	return -EINVAL;
}

static inline void
710 711
perf_cgroup_set_timestamp(struct task_struct *task,
			  struct perf_event_context *ctx)
S
Stephane Eranian 已提交
712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741
{
}

void
perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
{
}

static inline void
perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
{
}

static inline u64 perf_cgroup_event_time(struct perf_event *event)
{
	return 0;
}

static inline void
perf_cgroup_defer_enabled(struct perf_event *event)
{
}

static inline void
perf_cgroup_mark_enabled(struct perf_event *event,
			 struct perf_event_context *ctx)
{
}
#endif

742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804
/*
 * set default to be dependent on timer tick just
 * like original code
 */
#define PERF_CPU_HRTIMER (1000 / HZ)
/*
 * function must be called with interrupts disbled
 */
static enum hrtimer_restart perf_cpu_hrtimer_handler(struct hrtimer *hr)
{
	struct perf_cpu_context *cpuctx;
	enum hrtimer_restart ret = HRTIMER_NORESTART;
	int rotations = 0;

	WARN_ON(!irqs_disabled());

	cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);

	rotations = perf_rotate_context(cpuctx);

	/*
	 * arm timer if needed
	 */
	if (rotations) {
		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
		ret = HRTIMER_RESTART;
	}

	return ret;
}

/* CPU is going down */
void perf_cpu_hrtimer_cancel(int cpu)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	if (WARN_ON(cpu != smp_processor_id()))
		return;

	local_irq_save(flags);

	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);

		if (pmu->task_ctx_nr == perf_sw_context)
			continue;

		hrtimer_cancel(&cpuctx->hrtimer);
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

static void __perf_cpu_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
{
	struct hrtimer *hr = &cpuctx->hrtimer;
	struct pmu *pmu = cpuctx->ctx.pmu;
805
	int timer;
806 807 808 809 810

	/* no multiplexing needed for SW PMU */
	if (pmu->task_ctx_nr == perf_sw_context)
		return;

811 812 813 814 815 816 817 818 819
	/*
	 * check default is sane, if not set then force to
	 * default interval (1/tick)
	 */
	timer = pmu->hrtimer_interval_ms;
	if (timer < 1)
		timer = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;

	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841

	hrtimer_init(hr, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
	hr->function = perf_cpu_hrtimer_handler;
}

static void perf_cpu_hrtimer_restart(struct perf_cpu_context *cpuctx)
{
	struct hrtimer *hr = &cpuctx->hrtimer;
	struct pmu *pmu = cpuctx->ctx.pmu;

	/* not for SW PMU */
	if (pmu->task_ctx_nr == perf_sw_context)
		return;

	if (hrtimer_active(hr))
		return;

	if (!hrtimer_callback_running(hr))
		__hrtimer_start_range_ns(hr, cpuctx->hrtimer_interval,
					 0, HRTIMER_MODE_REL_PINNED, 0);
}

P
Peter Zijlstra 已提交
842
void perf_pmu_disable(struct pmu *pmu)
843
{
P
Peter Zijlstra 已提交
844 845 846
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!(*count)++)
		pmu->pmu_disable(pmu);
847 848
}

P
Peter Zijlstra 已提交
849
void perf_pmu_enable(struct pmu *pmu)
850
{
P
Peter Zijlstra 已提交
851 852 853
	int *count = this_cpu_ptr(pmu->pmu_disable_count);
	if (!--(*count))
		pmu->pmu_enable(pmu);
854 855
}

856
static DEFINE_PER_CPU(struct list_head, active_ctx_list);
857 858

/*
859 860 861 862
 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
 * perf_event_task_tick() are fully serialized because they're strictly cpu
 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
 * disabled, while perf_event_task_tick is called from IRQ context.
863
 */
864
static void perf_event_ctx_activate(struct perf_event_context *ctx)
865
{
866
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
867

868
	WARN_ON(!irqs_disabled());
869

870 871 872 873 874 875 876 877 878 879 880 881
	WARN_ON(!list_empty(&ctx->active_ctx_list));

	list_add(&ctx->active_ctx_list, head);
}

static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
{
	WARN_ON(!irqs_disabled());

	WARN_ON(list_empty(&ctx->active_ctx_list));

	list_del_init(&ctx->active_ctx_list);
882 883
}

884
static void get_ctx(struct perf_event_context *ctx)
885
{
886
	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
887 888
}

889 890 891 892 893 894 895 896 897
static void free_ctx(struct rcu_head *head)
{
	struct perf_event_context *ctx;

	ctx = container_of(head, struct perf_event_context, rcu_head);
	kfree(ctx->task_ctx_data);
	kfree(ctx);
}

898
static void put_ctx(struct perf_event_context *ctx)
899
{
900 901 902
	if (atomic_dec_and_test(&ctx->refcount)) {
		if (ctx->parent_ctx)
			put_ctx(ctx->parent_ctx);
903 904
		if (ctx->task)
			put_task_struct(ctx->task);
905
		call_rcu(&ctx->rcu_head, free_ctx);
906
	}
907 908
}

P
Peter Zijlstra 已提交
909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949
/*
 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
 * perf_pmu_migrate_context() we need some magic.
 *
 * Those places that change perf_event::ctx will hold both
 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
 *
 * Lock ordering is by mutex address. There is one other site where
 * perf_event_context::mutex nests and that is put_event(). But remember that
 * that is a parent<->child context relation, and migration does not affect
 * children, therefore these two orderings should not interact.
 *
 * The change in perf_event::ctx does not affect children (as claimed above)
 * because the sys_perf_event_open() case will install a new event and break
 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
 * concerned with cpuctx and that doesn't have children.
 *
 * The places that change perf_event::ctx will issue:
 *
 *   perf_remove_from_context();
 *   synchronize_rcu();
 *   perf_install_in_context();
 *
 * to affect the change. The remove_from_context() + synchronize_rcu() should
 * quiesce the event, after which we can install it in the new location. This
 * means that only external vectors (perf_fops, prctl) can perturb the event
 * while in transit. Therefore all such accessors should also acquire
 * perf_event_context::mutex to serialize against this.
 *
 * However; because event->ctx can change while we're waiting to acquire
 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
 * function.
 *
 * Lock order:
 *	task_struct::perf_event_mutex
 *	  perf_event_context::mutex
 *	    perf_event_context::lock
 *	    perf_event::child_mutex;
 *	    perf_event::mmap_mutex
 *	    mmap_sem
 */
P
Peter Zijlstra 已提交
950 951
static struct perf_event_context *
perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
P
Peter Zijlstra 已提交
952 953 954 955 956 957 958 959 960 961 962 963
{
	struct perf_event_context *ctx;

again:
	rcu_read_lock();
	ctx = ACCESS_ONCE(event->ctx);
	if (!atomic_inc_not_zero(&ctx->refcount)) {
		rcu_read_unlock();
		goto again;
	}
	rcu_read_unlock();

P
Peter Zijlstra 已提交
964
	mutex_lock_nested(&ctx->mutex, nesting);
P
Peter Zijlstra 已提交
965 966 967 968 969 970 971 972 973
	if (event->ctx != ctx) {
		mutex_unlock(&ctx->mutex);
		put_ctx(ctx);
		goto again;
	}

	return ctx;
}

P
Peter Zijlstra 已提交
974 975 976 977 978 979
static inline struct perf_event_context *
perf_event_ctx_lock(struct perf_event *event)
{
	return perf_event_ctx_lock_nested(event, 0);
}

P
Peter Zijlstra 已提交
980 981 982 983 984 985 986
static void perf_event_ctx_unlock(struct perf_event *event,
				  struct perf_event_context *ctx)
{
	mutex_unlock(&ctx->mutex);
	put_ctx(ctx);
}

987 988 989 990 991 992 993
/*
 * This must be done under the ctx->lock, such as to serialize against
 * context_equiv(), therefore we cannot call put_ctx() since that might end up
 * calling scheduler related locks and ctx->lock nests inside those.
 */
static __must_check struct perf_event_context *
unclone_ctx(struct perf_event_context *ctx)
994
{
995 996 997 998 999
	struct perf_event_context *parent_ctx = ctx->parent_ctx;

	lockdep_assert_held(&ctx->lock);

	if (parent_ctx)
1000
		ctx->parent_ctx = NULL;
1001
	ctx->generation++;
1002 1003

	return parent_ctx;
1004 1005
}

1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027
static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
{
	/*
	 * only top level events have the pid namespace they were created in
	 */
	if (event->parent)
		event = event->parent;

	return task_tgid_nr_ns(p, event->ns);
}

static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
{
	/*
	 * only top level events have the pid namespace they were created in
	 */
	if (event->parent)
		event = event->parent;

	return task_pid_nr_ns(p, event->ns);
}

1028
/*
1029
 * If we inherit events we want to return the parent event id
1030 1031
 * to userspace.
 */
1032
static u64 primary_event_id(struct perf_event *event)
1033
{
1034
	u64 id = event->id;
1035

1036 1037
	if (event->parent)
		id = event->parent->id;
1038 1039 1040 1041

	return id;
}

1042
/*
1043
 * Get the perf_event_context for a task and lock it.
1044 1045 1046
 * This has to cope with with the fact that until it is locked,
 * the context could get moved to another task.
 */
1047
static struct perf_event_context *
P
Peter Zijlstra 已提交
1048
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1049
{
1050
	struct perf_event_context *ctx;
1051

P
Peter Zijlstra 已提交
1052
retry:
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063
	/*
	 * One of the few rules of preemptible RCU is that one cannot do
	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
	 * part of the read side critical section was preemptible -- see
	 * rcu_read_unlock_special().
	 *
	 * Since ctx->lock nests under rq->lock we must ensure the entire read
	 * side critical section is non-preemptible.
	 */
	preempt_disable();
	rcu_read_lock();
P
Peter Zijlstra 已提交
1064
	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1065 1066 1067 1068
	if (ctx) {
		/*
		 * If this context is a clone of another, it might
		 * get swapped for another underneath us by
1069
		 * perf_event_task_sched_out, though the
1070 1071 1072 1073 1074 1075
		 * rcu_read_lock() protects us from any context
		 * getting freed.  Lock the context and check if it
		 * got swapped before we could get the lock, and retry
		 * if so.  If we locked the right context, then it
		 * can't get swapped on us any more.
		 */
1076
		raw_spin_lock_irqsave(&ctx->lock, *flags);
P
Peter Zijlstra 已提交
1077
		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1078
			raw_spin_unlock_irqrestore(&ctx->lock, *flags);
1079 1080
			rcu_read_unlock();
			preempt_enable();
1081 1082
			goto retry;
		}
1083 1084

		if (!atomic_inc_not_zero(&ctx->refcount)) {
1085
			raw_spin_unlock_irqrestore(&ctx->lock, *flags);
1086 1087
			ctx = NULL;
		}
1088 1089
	}
	rcu_read_unlock();
1090
	preempt_enable();
1091 1092 1093 1094 1095 1096 1097 1098
	return ctx;
}

/*
 * Get the context for a task and increment its pin_count so it
 * can't get swapped to another task.  This also increments its
 * reference count so that the context can't get freed.
 */
P
Peter Zijlstra 已提交
1099 1100
static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
1101
{
1102
	struct perf_event_context *ctx;
1103 1104
	unsigned long flags;

P
Peter Zijlstra 已提交
1105
	ctx = perf_lock_task_context(task, ctxn, &flags);
1106 1107
	if (ctx) {
		++ctx->pin_count;
1108
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1109 1110 1111 1112
	}
	return ctx;
}

1113
static void perf_unpin_context(struct perf_event_context *ctx)
1114 1115 1116
{
	unsigned long flags;

1117
	raw_spin_lock_irqsave(&ctx->lock, flags);
1118
	--ctx->pin_count;
1119
	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1120 1121
}

1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132
/*
 * Update the record of the current time in a context.
 */
static void update_context_time(struct perf_event_context *ctx)
{
	u64 now = perf_clock();

	ctx->time += now - ctx->timestamp;
	ctx->timestamp = now;
}

1133 1134 1135
static u64 perf_event_time(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
S
Stephane Eranian 已提交
1136 1137 1138 1139

	if (is_cgroup_event(event))
		return perf_cgroup_event_time(event);

1140 1141 1142
	return ctx ? ctx->time : 0;
}

1143 1144
/*
 * Update the total_time_enabled and total_time_running fields for a event.
1145
 * The caller of this function needs to hold the ctx->lock.
1146 1147 1148 1149 1150 1151 1152 1153 1154
 */
static void update_event_times(struct perf_event *event)
{
	struct perf_event_context *ctx = event->ctx;
	u64 run_end;

	if (event->state < PERF_EVENT_STATE_INACTIVE ||
	    event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
		return;
S
Stephane Eranian 已提交
1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165
	/*
	 * in cgroup mode, time_enabled represents
	 * the time the event was enabled AND active
	 * tasks were in the monitored cgroup. This is
	 * independent of the activity of the context as
	 * there may be a mix of cgroup and non-cgroup events.
	 *
	 * That is why we treat cgroup events differently
	 * here.
	 */
	if (is_cgroup_event(event))
1166
		run_end = perf_cgroup_event_time(event);
S
Stephane Eranian 已提交
1167 1168
	else if (ctx->is_active)
		run_end = ctx->time;
1169 1170 1171 1172
	else
		run_end = event->tstamp_stopped;

	event->total_time_enabled = run_end - event->tstamp_enabled;
1173 1174 1175 1176

	if (event->state == PERF_EVENT_STATE_INACTIVE)
		run_end = event->tstamp_stopped;
	else
1177
		run_end = perf_event_time(event);
1178 1179

	event->total_time_running = run_end - event->tstamp_running;
S
Stephane Eranian 已提交
1180

1181 1182
}

1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194
/*
 * Update total_time_enabled and total_time_running for all events in a group.
 */
static void update_group_times(struct perf_event *leader)
{
	struct perf_event *event;

	update_event_times(leader);
	list_for_each_entry(event, &leader->sibling_list, group_entry)
		update_event_times(event);
}

1195 1196 1197 1198 1199 1200 1201 1202 1203
static struct list_head *
ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
{
	if (event->attr.pinned)
		return &ctx->pinned_groups;
	else
		return &ctx->flexible_groups;
}

1204
/*
1205
 * Add a event from the lists for its context.
1206 1207
 * Must be called with ctx->mutex and ctx->lock held.
 */
1208
static void
1209
list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1210
{
1211 1212
	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
	event->attach_state |= PERF_ATTACH_CONTEXT;
1213 1214

	/*
1215 1216 1217
	 * If we're a stand alone event or group leader, we go to the context
	 * list, group events are kept attached to the group so that
	 * perf_group_detach can, at all times, locate all siblings.
1218
	 */
1219
	if (event->group_leader == event) {
1220 1221
		struct list_head *list;

1222 1223 1224
		if (is_software_event(event))
			event->group_flags |= PERF_GROUP_SOFTWARE;

1225 1226
		list = ctx_group_list(event, ctx);
		list_add_tail(&event->group_entry, list);
P
Peter Zijlstra 已提交
1227
	}
P
Peter Zijlstra 已提交
1228

1229
	if (is_cgroup_event(event))
S
Stephane Eranian 已提交
1230 1231
		ctx->nr_cgroups++;

1232 1233 1234
	list_add_rcu(&event->event_entry, &ctx->event_list);
	ctx->nr_events++;
	if (event->attr.inherit_stat)
1235
		ctx->nr_stat++;
1236 1237

	ctx->generation++;
1238 1239
}

J
Jiri Olsa 已提交
1240 1241 1242 1243 1244 1245 1246 1247 1248
/*
 * Initialize event state based on the perf_event_attr::disabled.
 */
static inline void perf_event__state_init(struct perf_event *event)
{
	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
					      PERF_EVENT_STATE_INACTIVE;
}

1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
/*
 * Called at perf_event creation and when events are attached/detached from a
 * group.
 */
static void perf_event__read_size(struct perf_event *event)
{
	int entry = sizeof(u64); /* value */
	int size = 0;
	int nr = 1;

	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		size += sizeof(u64);

	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		size += sizeof(u64);

	if (event->attr.read_format & PERF_FORMAT_ID)
		entry += sizeof(u64);

	if (event->attr.read_format & PERF_FORMAT_GROUP) {
		nr += event->group_leader->nr_siblings;
		size += sizeof(u64);
	}

	size += entry * nr;
	event->read_size = size;
}

static void perf_event__header_size(struct perf_event *event)
{
	struct perf_sample_data *data;
	u64 sample_type = event->attr.sample_type;
	u16 size = 0;

	perf_event__read_size(event);

	if (sample_type & PERF_SAMPLE_IP)
		size += sizeof(data->ip);

1288 1289 1290 1291 1292 1293
	if (sample_type & PERF_SAMPLE_ADDR)
		size += sizeof(data->addr);

	if (sample_type & PERF_SAMPLE_PERIOD)
		size += sizeof(data->period);

A
Andi Kleen 已提交
1294 1295 1296
	if (sample_type & PERF_SAMPLE_WEIGHT)
		size += sizeof(data->weight);

1297 1298 1299
	if (sample_type & PERF_SAMPLE_READ)
		size += event->read_size;

1300 1301 1302
	if (sample_type & PERF_SAMPLE_DATA_SRC)
		size += sizeof(data->data_src.val);

A
Andi Kleen 已提交
1303 1304 1305
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		size += sizeof(data->txn);

1306 1307 1308 1309 1310 1311 1312 1313 1314
	event->header_size = size;
}

static void perf_event__id_header_size(struct perf_event *event)
{
	struct perf_sample_data *data;
	u64 sample_type = event->attr.sample_type;
	u16 size = 0;

1315 1316 1317 1318 1319 1320
	if (sample_type & PERF_SAMPLE_TID)
		size += sizeof(data->tid_entry);

	if (sample_type & PERF_SAMPLE_TIME)
		size += sizeof(data->time);

1321 1322 1323
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		size += sizeof(data->id);

1324 1325 1326 1327 1328 1329 1330 1331 1332
	if (sample_type & PERF_SAMPLE_ID)
		size += sizeof(data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		size += sizeof(data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		size += sizeof(data->cpu_entry);

1333
	event->id_header_size = size;
1334 1335
}

1336 1337
static void perf_group_attach(struct perf_event *event)
{
1338
	struct perf_event *group_leader = event->group_leader, *pos;
1339

P
Peter Zijlstra 已提交
1340 1341 1342 1343 1344 1345
	/*
	 * We can have double attach due to group movement in perf_event_open.
	 */
	if (event->attach_state & PERF_ATTACH_GROUP)
		return;

1346 1347 1348 1349 1350
	event->attach_state |= PERF_ATTACH_GROUP;

	if (group_leader == event)
		return;

P
Peter Zijlstra 已提交
1351 1352
	WARN_ON_ONCE(group_leader->ctx != event->ctx);

1353 1354 1355 1356 1357 1358
	if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
			!is_software_event(event))
		group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;

	list_add_tail(&event->group_entry, &group_leader->sibling_list);
	group_leader->nr_siblings++;
1359 1360 1361 1362 1363

	perf_event__header_size(group_leader);

	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
		perf_event__header_size(pos);
1364 1365
}

1366
/*
1367
 * Remove a event from the lists for its context.
1368
 * Must be called with ctx->mutex and ctx->lock held.
1369
 */
1370
static void
1371
list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1372
{
1373
	struct perf_cpu_context *cpuctx;
P
Peter Zijlstra 已提交
1374 1375 1376 1377

	WARN_ON_ONCE(event->ctx != ctx);
	lockdep_assert_held(&ctx->lock);

1378 1379 1380 1381
	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1382
		return;
1383 1384 1385

	event->attach_state &= ~PERF_ATTACH_CONTEXT;

1386
	if (is_cgroup_event(event)) {
S
Stephane Eranian 已提交
1387
		ctx->nr_cgroups--;
1388 1389 1390 1391 1392 1393 1394 1395 1396
		cpuctx = __get_cpu_context(ctx);
		/*
		 * if there are no more cgroup events
		 * then cler cgrp to avoid stale pointer
		 * in update_cgrp_time_from_cpuctx()
		 */
		if (!ctx->nr_cgroups)
			cpuctx->cgrp = NULL;
	}
S
Stephane Eranian 已提交
1397

1398 1399
	ctx->nr_events--;
	if (event->attr.inherit_stat)
1400
		ctx->nr_stat--;
1401

1402
	list_del_rcu(&event->event_entry);
1403

1404 1405
	if (event->group_leader == event)
		list_del_init(&event->group_entry);
P
Peter Zijlstra 已提交
1406

1407
	update_group_times(event);
1408 1409 1410 1411 1412 1413 1414 1415 1416 1417

	/*
	 * If event was in error state, then keep it
	 * that way, otherwise bogus counts will be
	 * returned on read(). The only way to get out
	 * of error state is by explicit re-enabling
	 * of the event
	 */
	if (event->state > PERF_EVENT_STATE_OFF)
		event->state = PERF_EVENT_STATE_OFF;
1418 1419

	ctx->generation++;
1420 1421
}

1422
static void perf_group_detach(struct perf_event *event)
1423 1424
{
	struct perf_event *sibling, *tmp;
1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440
	struct list_head *list = NULL;

	/*
	 * We can have double detach due to exit/hot-unplug + close.
	 */
	if (!(event->attach_state & PERF_ATTACH_GROUP))
		return;

	event->attach_state &= ~PERF_ATTACH_GROUP;

	/*
	 * If this is a sibling, remove it from its group.
	 */
	if (event->group_leader != event) {
		list_del_init(&event->group_entry);
		event->group_leader->nr_siblings--;
1441
		goto out;
1442 1443 1444 1445
	}

	if (!list_empty(&event->group_entry))
		list = &event->group_entry;
1446

1447
	/*
1448 1449
	 * If this was a group event with sibling events then
	 * upgrade the siblings to singleton events by adding them
1450
	 * to whatever list we are on.
1451
	 */
1452
	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1453 1454
		if (list)
			list_move_tail(&sibling->group_entry, list);
1455
		sibling->group_leader = sibling;
1456 1457 1458

		/* Inherit group flags from the previous leader */
		sibling->group_flags = event->group_flags;
P
Peter Zijlstra 已提交
1459 1460

		WARN_ON_ONCE(sibling->ctx != event->ctx);
1461
	}
1462 1463 1464 1465 1466 1467

out:
	perf_event__header_size(event->group_leader);

	list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
		perf_event__header_size(tmp);
1468 1469
}

1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508
/*
 * User event without the task.
 */
static bool is_orphaned_event(struct perf_event *event)
{
	return event && !is_kernel_event(event) && !event->owner;
}

/*
 * Event has a parent but parent's task finished and it's
 * alive only because of children holding refference.
 */
static bool is_orphaned_child(struct perf_event *event)
{
	return is_orphaned_event(event->parent);
}

static void orphans_remove_work(struct work_struct *work);

static void schedule_orphans_remove(struct perf_event_context *ctx)
{
	if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
		return;

	if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
		get_ctx(ctx);
		ctx->orphans_remove_sched = true;
	}
}

static int __init perf_workqueue_init(void)
{
	perf_wq = create_singlethread_workqueue("perf");
	WARN(!perf_wq, "failed to create perf workqueue\n");
	return perf_wq ? 0 : -1;
}

core_initcall(perf_workqueue_init);

1509 1510 1511
static inline int
event_filter_match(struct perf_event *event)
{
S
Stephane Eranian 已提交
1512 1513
	return (event->cpu == -1 || event->cpu == smp_processor_id())
	    && perf_cgroup_match(event);
1514 1515
}

1516 1517
static void
event_sched_out(struct perf_event *event,
1518
		  struct perf_cpu_context *cpuctx,
1519
		  struct perf_event_context *ctx)
1520
{
1521
	u64 tstamp = perf_event_time(event);
1522
	u64 delta;
P
Peter Zijlstra 已提交
1523 1524 1525 1526

	WARN_ON_ONCE(event->ctx != ctx);
	lockdep_assert_held(&ctx->lock);

1527 1528 1529 1530 1531 1532 1533 1534
	/*
	 * An event which could not be activated because of
	 * filter mismatch still needs to have its timings
	 * maintained, otherwise bogus information is return
	 * via read() for time_enabled, time_running:
	 */
	if (event->state == PERF_EVENT_STATE_INACTIVE
	    && !event_filter_match(event)) {
S
Stephane Eranian 已提交
1535
		delta = tstamp - event->tstamp_stopped;
1536
		event->tstamp_running += delta;
1537
		event->tstamp_stopped = tstamp;
1538 1539
	}

1540
	if (event->state != PERF_EVENT_STATE_ACTIVE)
1541
		return;
1542

1543 1544
	perf_pmu_disable(event->pmu);

1545 1546 1547 1548
	event->state = PERF_EVENT_STATE_INACTIVE;
	if (event->pending_disable) {
		event->pending_disable = 0;
		event->state = PERF_EVENT_STATE_OFF;
1549
	}
1550
	event->tstamp_stopped = tstamp;
P
Peter Zijlstra 已提交
1551
	event->pmu->del(event, 0);
1552
	event->oncpu = -1;
1553

1554
	if (!is_software_event(event))
1555
		cpuctx->active_oncpu--;
1556 1557
	if (!--ctx->nr_active)
		perf_event_ctx_deactivate(ctx);
1558 1559
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq--;
1560
	if (event->attr.exclusive || !cpuctx->active_oncpu)
1561
		cpuctx->exclusive = 0;
1562

1563 1564 1565
	if (is_orphaned_child(event))
		schedule_orphans_remove(ctx);

1566
	perf_pmu_enable(event->pmu);
1567 1568
}

1569
static void
1570
group_sched_out(struct perf_event *group_event,
1571
		struct perf_cpu_context *cpuctx,
1572
		struct perf_event_context *ctx)
1573
{
1574
	struct perf_event *event;
1575
	int state = group_event->state;
1576

1577
	event_sched_out(group_event, cpuctx, ctx);
1578 1579 1580 1581

	/*
	 * Schedule out siblings (if any):
	 */
1582 1583
	list_for_each_entry(event, &group_event->sibling_list, group_entry)
		event_sched_out(event, cpuctx, ctx);
1584

1585
	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1586 1587 1588
		cpuctx->exclusive = 0;
}

1589 1590 1591 1592 1593
struct remove_event {
	struct perf_event *event;
	bool detach_group;
};

T
Thomas Gleixner 已提交
1594
/*
1595
 * Cross CPU call to remove a performance event
T
Thomas Gleixner 已提交
1596
 *
1597
 * We disable the event on the hardware level first. After that we
T
Thomas Gleixner 已提交
1598 1599
 * remove it from the context list.
 */
1600
static int __perf_remove_from_context(void *info)
T
Thomas Gleixner 已提交
1601
{
1602 1603
	struct remove_event *re = info;
	struct perf_event *event = re->event;
1604
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
1605
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
T
Thomas Gleixner 已提交
1606

1607
	raw_spin_lock(&ctx->lock);
1608
	event_sched_out(event, cpuctx, ctx);
1609 1610
	if (re->detach_group)
		perf_group_detach(event);
1611
	list_del_event(event, ctx);
1612 1613 1614 1615
	if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
		ctx->is_active = 0;
		cpuctx->task_ctx = NULL;
	}
1616
	raw_spin_unlock(&ctx->lock);
1617 1618

	return 0;
T
Thomas Gleixner 已提交
1619 1620 1621 1622
}


/*
1623
 * Remove the event from a task's (or a CPU's) list of events.
T
Thomas Gleixner 已提交
1624
 *
1625
 * CPU events are removed with a smp call. For task events we only
T
Thomas Gleixner 已提交
1626
 * call when the task is on a CPU.
1627
 *
1628 1629
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1630 1631
 * remains valid.  This is OK when called from perf_release since
 * that only calls us on the top-level context, which can't be a clone.
1632
 * When called from perf_event_exit_task, it's OK because the
1633
 * context has been detached from its task.
T
Thomas Gleixner 已提交
1634
 */
1635
static void perf_remove_from_context(struct perf_event *event, bool detach_group)
T
Thomas Gleixner 已提交
1636
{
1637
	struct perf_event_context *ctx = event->ctx;
T
Thomas Gleixner 已提交
1638
	struct task_struct *task = ctx->task;
1639 1640 1641 1642
	struct remove_event re = {
		.event = event,
		.detach_group = detach_group,
	};
T
Thomas Gleixner 已提交
1643

1644 1645
	lockdep_assert_held(&ctx->mutex);

T
Thomas Gleixner 已提交
1646 1647
	if (!task) {
		/*
1648 1649 1650 1651
		 * Per cpu events are removed via an smp call. The removal can
		 * fail if the CPU is currently offline, but in that case we
		 * already called __perf_remove_from_context from
		 * perf_event_exit_cpu.
T
Thomas Gleixner 已提交
1652
		 */
1653
		cpu_function_call(event->cpu, __perf_remove_from_context, &re);
T
Thomas Gleixner 已提交
1654 1655 1656 1657
		return;
	}

retry:
1658
	if (!task_function_call(task, __perf_remove_from_context, &re))
1659
		return;
T
Thomas Gleixner 已提交
1660

1661
	raw_spin_lock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1662
	/*
1663 1664
	 * If we failed to find a running task, but find the context active now
	 * that we've acquired the ctx->lock, retry.
T
Thomas Gleixner 已提交
1665
	 */
1666
	if (ctx->is_active) {
1667
		raw_spin_unlock_irq(&ctx->lock);
1668 1669 1670 1671 1672
		/*
		 * Reload the task pointer, it might have been changed by
		 * a concurrent perf_event_context_sched_out().
		 */
		task = ctx->task;
T
Thomas Gleixner 已提交
1673 1674 1675 1676
		goto retry;
	}

	/*
1677 1678
	 * Since the task isn't running, its safe to remove the event, us
	 * holding the ctx->lock ensures the task won't get scheduled in.
T
Thomas Gleixner 已提交
1679
	 */
1680 1681
	if (detach_group)
		perf_group_detach(event);
1682
	list_del_event(event, ctx);
1683
	raw_spin_unlock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
1684 1685
}

1686
/*
1687
 * Cross CPU call to disable a performance event
1688
 */
1689
int __perf_event_disable(void *info)
1690
{
1691 1692
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
1693
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1694 1695

	/*
1696 1697
	 * If this is a per-task event, need to check whether this
	 * event's task is the current task on this cpu.
1698 1699 1700
	 *
	 * Can trigger due to concurrent perf_event_context_sched_out()
	 * flipping contexts around.
1701
	 */
1702
	if (ctx->task && cpuctx->task_ctx != ctx)
1703
		return -EINVAL;
1704

1705
	raw_spin_lock(&ctx->lock);
1706 1707

	/*
1708
	 * If the event is on, turn it off.
1709 1710
	 * If it is in error state, leave it in error state.
	 */
1711
	if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1712
		update_context_time(ctx);
S
Stephane Eranian 已提交
1713
		update_cgrp_time_from_event(event);
1714 1715 1716
		update_group_times(event);
		if (event == event->group_leader)
			group_sched_out(event, cpuctx, ctx);
1717
		else
1718 1719
			event_sched_out(event, cpuctx, ctx);
		event->state = PERF_EVENT_STATE_OFF;
1720 1721
	}

1722
	raw_spin_unlock(&ctx->lock);
1723 1724

	return 0;
1725 1726 1727
}

/*
1728
 * Disable a event.
1729
 *
1730 1731
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
1732
 * remains valid.  This condition is satisifed when called through
1733 1734 1735 1736
 * perf_event_for_each_child or perf_event_for_each because they
 * hold the top-level event's child_mutex, so any descendant that
 * goes to exit will block in sync_child_event.
 * When called from perf_pending_event it's OK because event->ctx
1737
 * is the current context on this CPU and preemption is disabled,
1738
 * hence we can't get into perf_event_task_sched_out for this context.
1739
 */
P
Peter Zijlstra 已提交
1740
static void _perf_event_disable(struct perf_event *event)
1741
{
1742
	struct perf_event_context *ctx = event->ctx;
1743 1744 1745 1746
	struct task_struct *task = ctx->task;

	if (!task) {
		/*
1747
		 * Disable the event on the cpu that it's on
1748
		 */
1749
		cpu_function_call(event->cpu, __perf_event_disable, event);
1750 1751 1752
		return;
	}

P
Peter Zijlstra 已提交
1753
retry:
1754 1755
	if (!task_function_call(task, __perf_event_disable, event))
		return;
1756

1757
	raw_spin_lock_irq(&ctx->lock);
1758
	/*
1759
	 * If the event is still active, we need to retry the cross-call.
1760
	 */
1761
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
1762
		raw_spin_unlock_irq(&ctx->lock);
1763 1764 1765 1766 1767
		/*
		 * Reload the task pointer, it might have been changed by
		 * a concurrent perf_event_context_sched_out().
		 */
		task = ctx->task;
1768 1769 1770 1771 1772 1773 1774
		goto retry;
	}

	/*
	 * Since we have the lock this context can't be scheduled
	 * in, so we can change the state safely.
	 */
1775 1776 1777
	if (event->state == PERF_EVENT_STATE_INACTIVE) {
		update_group_times(event);
		event->state = PERF_EVENT_STATE_OFF;
1778
	}
1779
	raw_spin_unlock_irq(&ctx->lock);
1780
}
P
Peter Zijlstra 已提交
1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793

/*
 * Strictly speaking kernel users cannot create groups and therefore this
 * interface does not need the perf_event_ctx_lock() magic.
 */
void perf_event_disable(struct perf_event *event)
{
	struct perf_event_context *ctx;

	ctx = perf_event_ctx_lock(event);
	_perf_event_disable(event);
	perf_event_ctx_unlock(event, ctx);
}
1794
EXPORT_SYMBOL_GPL(perf_event_disable);
1795

S
Stephane Eranian 已提交
1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830
static void perf_set_shadow_time(struct perf_event *event,
				 struct perf_event_context *ctx,
				 u64 tstamp)
{
	/*
	 * use the correct time source for the time snapshot
	 *
	 * We could get by without this by leveraging the
	 * fact that to get to this function, the caller
	 * has most likely already called update_context_time()
	 * and update_cgrp_time_xx() and thus both timestamp
	 * are identical (or very close). Given that tstamp is,
	 * already adjusted for cgroup, we could say that:
	 *    tstamp - ctx->timestamp
	 * is equivalent to
	 *    tstamp - cgrp->timestamp.
	 *
	 * Then, in perf_output_read(), the calculation would
	 * work with no changes because:
	 * - event is guaranteed scheduled in
	 * - no scheduled out in between
	 * - thus the timestamp would be the same
	 *
	 * But this is a bit hairy.
	 *
	 * So instead, we have an explicit cgroup call to remain
	 * within the time time source all along. We believe it
	 * is cleaner and simpler to understand.
	 */
	if (is_cgroup_event(event))
		perf_cgroup_set_shadow_time(event, tstamp);
	else
		event->shadow_ctx_time = tstamp - ctx->timestamp;
}

P
Peter Zijlstra 已提交
1831 1832 1833
#define MAX_INTERRUPTS (~0ULL)

static void perf_log_throttle(struct perf_event *event, int enable);
1834
static void perf_log_itrace_start(struct perf_event *event);
P
Peter Zijlstra 已提交
1835

1836
static int
1837
event_sched_in(struct perf_event *event,
1838
		 struct perf_cpu_context *cpuctx,
1839
		 struct perf_event_context *ctx)
1840
{
1841
	u64 tstamp = perf_event_time(event);
1842
	int ret = 0;
1843

1844 1845
	lockdep_assert_held(&ctx->lock);

1846
	if (event->state <= PERF_EVENT_STATE_OFF)
1847 1848
		return 0;

1849
	event->state = PERF_EVENT_STATE_ACTIVE;
1850
	event->oncpu = smp_processor_id();
P
Peter Zijlstra 已提交
1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861

	/*
	 * Unthrottle events, since we scheduled we might have missed several
	 * ticks already, also for a heavily scheduling task there is little
	 * guarantee it'll get a tick in a timely manner.
	 */
	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
		perf_log_throttle(event, 1);
		event->hw.interrupts = 0;
	}

1862 1863 1864 1865 1866
	/*
	 * The new state must be visible before we turn it on in the hardware:
	 */
	smp_wmb();

1867 1868
	perf_pmu_disable(event->pmu);

1869 1870 1871 1872
	event->tstamp_running += tstamp - event->tstamp_stopped;

	perf_set_shadow_time(event, ctx, tstamp);

1873 1874
	perf_log_itrace_start(event);

P
Peter Zijlstra 已提交
1875
	if (event->pmu->add(event, PERF_EF_START)) {
1876 1877
		event->state = PERF_EVENT_STATE_INACTIVE;
		event->oncpu = -1;
1878 1879
		ret = -EAGAIN;
		goto out;
1880 1881
	}

1882
	if (!is_software_event(event))
1883
		cpuctx->active_oncpu++;
1884 1885
	if (!ctx->nr_active++)
		perf_event_ctx_activate(ctx);
1886 1887
	if (event->attr.freq && event->attr.sample_freq)
		ctx->nr_freq++;
1888

1889
	if (event->attr.exclusive)
1890 1891
		cpuctx->exclusive = 1;

1892 1893 1894
	if (is_orphaned_child(event))
		schedule_orphans_remove(ctx);

1895 1896 1897 1898
out:
	perf_pmu_enable(event->pmu);

	return ret;
1899 1900
}

1901
static int
1902
group_sched_in(struct perf_event *group_event,
1903
	       struct perf_cpu_context *cpuctx,
1904
	       struct perf_event_context *ctx)
1905
{
1906
	struct perf_event *event, *partial_group = NULL;
P
Peter Zijlstra 已提交
1907
	struct pmu *pmu = ctx->pmu;
1908 1909
	u64 now = ctx->time;
	bool simulate = false;
1910

1911
	if (group_event->state == PERF_EVENT_STATE_OFF)
1912 1913
		return 0;

P
Peter Zijlstra 已提交
1914
	pmu->start_txn(pmu);
1915

1916
	if (event_sched_in(group_event, cpuctx, ctx)) {
P
Peter Zijlstra 已提交
1917
		pmu->cancel_txn(pmu);
1918
		perf_cpu_hrtimer_restart(cpuctx);
1919
		return -EAGAIN;
1920
	}
1921 1922 1923 1924

	/*
	 * Schedule in siblings as one group (if any):
	 */
1925
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1926
		if (event_sched_in(event, cpuctx, ctx)) {
1927
			partial_group = event;
1928 1929 1930 1931
			goto group_error;
		}
	}

1932
	if (!pmu->commit_txn(pmu))
1933
		return 0;
1934

1935 1936 1937 1938
group_error:
	/*
	 * Groups can be scheduled in as one unit only, so undo any
	 * partial group before returning:
1939 1940 1941 1942 1943 1944 1945 1946 1947 1948
	 * The events up to the failed event are scheduled out normally,
	 * tstamp_stopped will be updated.
	 *
	 * The failed events and the remaining siblings need to have
	 * their timings updated as if they had gone thru event_sched_in()
	 * and event_sched_out(). This is required to get consistent timings
	 * across the group. This also takes care of the case where the group
	 * could never be scheduled by ensuring tstamp_stopped is set to mark
	 * the time the event was actually stopped, such that time delta
	 * calculation in update_event_times() is correct.
1949
	 */
1950 1951
	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
		if (event == partial_group)
1952 1953 1954 1955 1956 1957 1958 1959
			simulate = true;

		if (simulate) {
			event->tstamp_running += now - event->tstamp_stopped;
			event->tstamp_stopped = now;
		} else {
			event_sched_out(event, cpuctx, ctx);
		}
1960
	}
1961
	event_sched_out(group_event, cpuctx, ctx);
1962

P
Peter Zijlstra 已提交
1963
	pmu->cancel_txn(pmu);
1964

1965 1966
	perf_cpu_hrtimer_restart(cpuctx);

1967 1968 1969
	return -EAGAIN;
}

1970
/*
1971
 * Work out whether we can put this event group on the CPU now.
1972
 */
1973
static int group_can_go_on(struct perf_event *event,
1974 1975 1976 1977
			   struct perf_cpu_context *cpuctx,
			   int can_add_hw)
{
	/*
1978
	 * Groups consisting entirely of software events can always go on.
1979
	 */
1980
	if (event->group_flags & PERF_GROUP_SOFTWARE)
1981 1982 1983
		return 1;
	/*
	 * If an exclusive group is already on, no other hardware
1984
	 * events can go on.
1985 1986 1987 1988 1989
	 */
	if (cpuctx->exclusive)
		return 0;
	/*
	 * If this group is exclusive and there are already
1990
	 * events on the CPU, it can't go on.
1991
	 */
1992
	if (event->attr.exclusive && cpuctx->active_oncpu)
1993 1994 1995 1996 1997 1998 1999 2000
		return 0;
	/*
	 * Otherwise, try to add it if all previous groups were able
	 * to go on.
	 */
	return can_add_hw;
}

2001 2002
static void add_event_to_ctx(struct perf_event *event,
			       struct perf_event_context *ctx)
2003
{
2004 2005
	u64 tstamp = perf_event_time(event);

2006
	list_add_event(event, ctx);
2007
	perf_group_attach(event);
2008 2009 2010
	event->tstamp_enabled = tstamp;
	event->tstamp_running = tstamp;
	event->tstamp_stopped = tstamp;
2011 2012
}

2013 2014 2015 2016 2017 2018
static void task_ctx_sched_out(struct perf_event_context *ctx);
static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
	     enum event_type_t event_type,
	     struct task_struct *task);
2019

2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031
static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
				struct perf_event_context *ctx,
				struct task_struct *task)
{
	cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
	if (ctx)
		ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
	if (ctx)
		ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
}

T
Thomas Gleixner 已提交
2032
/*
2033
 * Cross CPU call to install and enable a performance event
2034 2035
 *
 * Must be called with ctx->mutex held
T
Thomas Gleixner 已提交
2036
 */
2037
static int  __perf_install_in_context(void *info)
T
Thomas Gleixner 已提交
2038
{
2039 2040
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
2041
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2042 2043 2044
	struct perf_event_context *task_ctx = cpuctx->task_ctx;
	struct task_struct *task = current;

2045
	perf_ctx_lock(cpuctx, task_ctx);
2046
	perf_pmu_disable(cpuctx->ctx.pmu);
T
Thomas Gleixner 已提交
2047 2048

	/*
2049
	 * If there was an active task_ctx schedule it out.
T
Thomas Gleixner 已提交
2050
	 */
2051
	if (task_ctx)
2052
		task_ctx_sched_out(task_ctx);
2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066

	/*
	 * If the context we're installing events in is not the
	 * active task_ctx, flip them.
	 */
	if (ctx->task && task_ctx != ctx) {
		if (task_ctx)
			raw_spin_unlock(&task_ctx->lock);
		raw_spin_lock(&ctx->lock);
		task_ctx = ctx;
	}

	if (task_ctx) {
		cpuctx->task_ctx = task_ctx;
2067 2068
		task = task_ctx->task;
	}
2069

2070
	cpu_ctx_sched_out(cpuctx, EVENT_ALL);
T
Thomas Gleixner 已提交
2071

2072
	update_context_time(ctx);
S
Stephane Eranian 已提交
2073 2074 2075 2076 2077 2078
	/*
	 * update cgrp time only if current cgrp
	 * matches event->cgrp. Must be done before
	 * calling add_event_to_ctx()
	 */
	update_cgrp_time_from_event(event);
T
Thomas Gleixner 已提交
2079

2080
	add_event_to_ctx(event, ctx);
T
Thomas Gleixner 已提交
2081

2082
	/*
2083
	 * Schedule everything back in
2084
	 */
2085
	perf_event_sched_in(cpuctx, task_ctx, task);
2086 2087 2088

	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, task_ctx);
2089 2090

	return 0;
T
Thomas Gleixner 已提交
2091 2092 2093
}

/*
2094
 * Attach a performance event to a context
T
Thomas Gleixner 已提交
2095
 *
2096 2097
 * First we add the event to the list with the hardware enable bit
 * in event->hw_config cleared.
T
Thomas Gleixner 已提交
2098
 *
2099
 * If the event is attached to a task which is on a CPU we use a smp
T
Thomas Gleixner 已提交
2100 2101 2102 2103
 * call to enable it in the task context. The task might have been
 * scheduled away, but we check this in the smp call again.
 */
static void
2104 2105
perf_install_in_context(struct perf_event_context *ctx,
			struct perf_event *event,
T
Thomas Gleixner 已提交
2106 2107 2108 2109
			int cpu)
{
	struct task_struct *task = ctx->task;

2110 2111
	lockdep_assert_held(&ctx->mutex);

2112
	event->ctx = ctx;
2113 2114
	if (event->cpu != -1)
		event->cpu = cpu;
2115

T
Thomas Gleixner 已提交
2116 2117
	if (!task) {
		/*
2118
		 * Per cpu events are installed via an smp call and
2119
		 * the install is always successful.
T
Thomas Gleixner 已提交
2120
		 */
2121
		cpu_function_call(cpu, __perf_install_in_context, event);
T
Thomas Gleixner 已提交
2122 2123 2124 2125
		return;
	}

retry:
2126 2127
	if (!task_function_call(task, __perf_install_in_context, event))
		return;
T
Thomas Gleixner 已提交
2128

2129
	raw_spin_lock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
2130
	/*
2131 2132
	 * If we failed to find a running task, but find the context active now
	 * that we've acquired the ctx->lock, retry.
T
Thomas Gleixner 已提交
2133
	 */
2134
	if (ctx->is_active) {
2135
		raw_spin_unlock_irq(&ctx->lock);
2136 2137 2138 2139 2140
		/*
		 * Reload the task pointer, it might have been changed by
		 * a concurrent perf_event_context_sched_out().
		 */
		task = ctx->task;
T
Thomas Gleixner 已提交
2141 2142 2143 2144
		goto retry;
	}

	/*
2145 2146
	 * Since the task isn't running, its safe to add the event, us holding
	 * the ctx->lock ensures the task won't get scheduled in.
T
Thomas Gleixner 已提交
2147
	 */
2148
	add_event_to_ctx(event, ctx);
2149
	raw_spin_unlock_irq(&ctx->lock);
T
Thomas Gleixner 已提交
2150 2151
}

2152
/*
2153
 * Put a event into inactive state and update time fields.
2154 2155 2156 2157 2158 2159
 * Enabling the leader of a group effectively enables all
 * the group members that aren't explicitly disabled, so we
 * have to update their ->tstamp_enabled also.
 * Note: this works for group members as well as group leaders
 * since the non-leader members' sibling_lists will be empty.
 */
2160
static void __perf_event_mark_enabled(struct perf_event *event)
2161
{
2162
	struct perf_event *sub;
2163
	u64 tstamp = perf_event_time(event);
2164

2165
	event->state = PERF_EVENT_STATE_INACTIVE;
2166
	event->tstamp_enabled = tstamp - event->total_time_enabled;
P
Peter Zijlstra 已提交
2167
	list_for_each_entry(sub, &event->sibling_list, group_entry) {
2168 2169
		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
P
Peter Zijlstra 已提交
2170
	}
2171 2172
}

2173
/*
2174
 * Cross CPU call to enable a performance event
2175
 */
2176
static int __perf_event_enable(void *info)
2177
{
2178 2179 2180
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *leader = event->group_leader;
P
Peter Zijlstra 已提交
2181
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2182
	int err;
2183

2184 2185 2186 2187 2188 2189 2190 2191 2192 2193
	/*
	 * There's a time window between 'ctx->is_active' check
	 * in perf_event_enable function and this place having:
	 *   - IRQs on
	 *   - ctx->lock unlocked
	 *
	 * where the task could be killed and 'ctx' deactivated
	 * by perf_event_exit_task.
	 */
	if (!ctx->is_active)
2194
		return -EINVAL;
2195

2196
	raw_spin_lock(&ctx->lock);
2197
	update_context_time(ctx);
2198

2199
	if (event->state >= PERF_EVENT_STATE_INACTIVE)
2200
		goto unlock;
S
Stephane Eranian 已提交
2201 2202 2203 2204

	/*
	 * set current task's cgroup time reference point
	 */
2205
	perf_cgroup_set_timestamp(current, ctx);
S
Stephane Eranian 已提交
2206

2207
	__perf_event_mark_enabled(event);
2208

S
Stephane Eranian 已提交
2209 2210 2211
	if (!event_filter_match(event)) {
		if (is_cgroup_event(event))
			perf_cgroup_defer_enabled(event);
2212
		goto unlock;
S
Stephane Eranian 已提交
2213
	}
2214

2215
	/*
2216
	 * If the event is in a group and isn't the group leader,
2217
	 * then don't put it on unless the group is on.
2218
	 */
2219
	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2220
		goto unlock;
2221

2222
	if (!group_can_go_on(event, cpuctx, 1)) {
2223
		err = -EEXIST;
2224
	} else {
2225
		if (event == leader)
2226
			err = group_sched_in(event, cpuctx, ctx);
2227
		else
2228
			err = event_sched_in(event, cpuctx, ctx);
2229
	}
2230 2231 2232

	if (err) {
		/*
2233
		 * If this event can't go on and it's part of a
2234 2235
		 * group, then the whole group has to come off.
		 */
2236
		if (leader != event) {
2237
			group_sched_out(leader, cpuctx, ctx);
2238 2239
			perf_cpu_hrtimer_restart(cpuctx);
		}
2240
		if (leader->attr.pinned) {
2241
			update_group_times(leader);
2242
			leader->state = PERF_EVENT_STATE_ERROR;
2243
		}
2244 2245
	}

P
Peter Zijlstra 已提交
2246
unlock:
2247
	raw_spin_unlock(&ctx->lock);
2248 2249

	return 0;
2250 2251 2252
}

/*
2253
 * Enable a event.
2254
 *
2255 2256
 * If event->ctx is a cloned context, callers must make sure that
 * every task struct that event->ctx->task could possibly point to
2257
 * remains valid.  This condition is satisfied when called through
2258 2259
 * perf_event_for_each_child or perf_event_for_each as described
 * for perf_event_disable.
2260
 */
P
Peter Zijlstra 已提交
2261
static void _perf_event_enable(struct perf_event *event)
2262
{
2263
	struct perf_event_context *ctx = event->ctx;
2264 2265 2266 2267
	struct task_struct *task = ctx->task;

	if (!task) {
		/*
2268
		 * Enable the event on the cpu that it's on
2269
		 */
2270
		cpu_function_call(event->cpu, __perf_event_enable, event);
2271 2272 2273
		return;
	}

2274
	raw_spin_lock_irq(&ctx->lock);
2275
	if (event->state >= PERF_EVENT_STATE_INACTIVE)
2276 2277 2278
		goto out;

	/*
2279 2280
	 * If the event is in error state, clear that first.
	 * That way, if we see the event in error state below, we
2281 2282 2283 2284
	 * know that it has gone back into error state, as distinct
	 * from the task having been scheduled away before the
	 * cross-call arrived.
	 */
2285 2286
	if (event->state == PERF_EVENT_STATE_ERROR)
		event->state = PERF_EVENT_STATE_OFF;
2287

P
Peter Zijlstra 已提交
2288
retry:
2289
	if (!ctx->is_active) {
2290
		__perf_event_mark_enabled(event);
2291 2292 2293
		goto out;
	}

2294
	raw_spin_unlock_irq(&ctx->lock);
2295 2296 2297

	if (!task_function_call(task, __perf_event_enable, event))
		return;
2298

2299
	raw_spin_lock_irq(&ctx->lock);
2300 2301

	/*
2302
	 * If the context is active and the event is still off,
2303 2304
	 * we need to retry the cross-call.
	 */
2305 2306 2307 2308 2309 2310
	if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
		/*
		 * task could have been flipped by a concurrent
		 * perf_event_context_sched_out()
		 */
		task = ctx->task;
2311
		goto retry;
2312
	}
2313

P
Peter Zijlstra 已提交
2314
out:
2315
	raw_spin_unlock_irq(&ctx->lock);
2316
}
P
Peter Zijlstra 已提交
2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328

/*
 * See perf_event_disable();
 */
void perf_event_enable(struct perf_event *event)
{
	struct perf_event_context *ctx;

	ctx = perf_event_ctx_lock(event);
	_perf_event_enable(event);
	perf_event_ctx_unlock(event, ctx);
}
2329
EXPORT_SYMBOL_GPL(perf_event_enable);
2330

P
Peter Zijlstra 已提交
2331
static int _perf_event_refresh(struct perf_event *event, int refresh)
2332
{
2333
	/*
2334
	 * not supported on inherited events
2335
	 */
2336
	if (event->attr.inherit || !is_sampling_event(event))
2337 2338
		return -EINVAL;

2339
	atomic_add(refresh, &event->event_limit);
P
Peter Zijlstra 已提交
2340
	_perf_event_enable(event);
2341 2342

	return 0;
2343
}
P
Peter Zijlstra 已提交
2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358

/*
 * See perf_event_disable()
 */
int perf_event_refresh(struct perf_event *event, int refresh)
{
	struct perf_event_context *ctx;
	int ret;

	ctx = perf_event_ctx_lock(event);
	ret = _perf_event_refresh(event, refresh);
	perf_event_ctx_unlock(event, ctx);

	return ret;
}
2359
EXPORT_SYMBOL_GPL(perf_event_refresh);
2360

2361 2362 2363
static void ctx_sched_out(struct perf_event_context *ctx,
			  struct perf_cpu_context *cpuctx,
			  enum event_type_t event_type)
2364
{
2365
	struct perf_event *event;
2366
	int is_active = ctx->is_active;
2367

2368
	ctx->is_active &= ~event_type;
2369
	if (likely(!ctx->nr_events))
2370 2371
		return;

2372
	update_context_time(ctx);
S
Stephane Eranian 已提交
2373
	update_cgrp_time_from_cpuctx(cpuctx);
2374
	if (!ctx->nr_active)
2375
		return;
2376

P
Peter Zijlstra 已提交
2377
	perf_pmu_disable(ctx->pmu);
2378
	if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2379 2380
		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2381
	}
2382

2383
	if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2384
		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2385
			group_sched_out(event, cpuctx, ctx);
P
Peter Zijlstra 已提交
2386
	}
P
Peter Zijlstra 已提交
2387
	perf_pmu_enable(ctx->pmu);
2388 2389
}

2390
/*
2391 2392 2393 2394 2395 2396
 * Test whether two contexts are equivalent, i.e. whether they have both been
 * cloned from the same version of the same context.
 *
 * Equivalence is measured using a generation number in the context that is
 * incremented on each modification to it; see unclone_ctx(), list_add_event()
 * and list_del_event().
2397
 */
2398 2399
static int context_equiv(struct perf_event_context *ctx1,
			 struct perf_event_context *ctx2)
2400
{
2401 2402 2403
	lockdep_assert_held(&ctx1->lock);
	lockdep_assert_held(&ctx2->lock);

2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425
	/* Pinning disables the swap optimization */
	if (ctx1->pin_count || ctx2->pin_count)
		return 0;

	/* If ctx1 is the parent of ctx2 */
	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
		return 1;

	/* If ctx2 is the parent of ctx1 */
	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
		return 1;

	/*
	 * If ctx1 and ctx2 have the same parent; we flatten the parent
	 * hierarchy, see perf_event_init_context().
	 */
	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
			ctx1->parent_gen == ctx2->parent_gen)
		return 1;

	/* Unmatched */
	return 0;
2426 2427
}

2428 2429
static void __perf_event_sync_stat(struct perf_event *event,
				     struct perf_event *next_event)
2430 2431 2432
{
	u64 value;

2433
	if (!event->attr.inherit_stat)
2434 2435 2436
		return;

	/*
2437
	 * Update the event value, we cannot use perf_event_read()
2438 2439
	 * because we're in the middle of a context switch and have IRQs
	 * disabled, which upsets smp_call_function_single(), however
2440
	 * we know the event must be on the current CPU, therefore we
2441 2442
	 * don't need to use it.
	 */
2443 2444
	switch (event->state) {
	case PERF_EVENT_STATE_ACTIVE:
2445 2446
		event->pmu->read(event);
		/* fall-through */
2447

2448 2449
	case PERF_EVENT_STATE_INACTIVE:
		update_event_times(event);
2450 2451 2452 2453 2454 2455 2456
		break;

	default:
		break;
	}

	/*
2457
	 * In order to keep per-task stats reliable we need to flip the event
2458 2459
	 * values when we flip the contexts.
	 */
2460 2461 2462
	value = local64_read(&next_event->count);
	value = local64_xchg(&event->count, value);
	local64_set(&next_event->count, value);
2463

2464 2465
	swap(event->total_time_enabled, next_event->total_time_enabled);
	swap(event->total_time_running, next_event->total_time_running);
2466

2467
	/*
2468
	 * Since we swizzled the values, update the user visible data too.
2469
	 */
2470 2471
	perf_event_update_userpage(event);
	perf_event_update_userpage(next_event);
2472 2473
}

2474 2475
static void perf_event_sync_stat(struct perf_event_context *ctx,
				   struct perf_event_context *next_ctx)
2476
{
2477
	struct perf_event *event, *next_event;
2478 2479 2480 2481

	if (!ctx->nr_stat)
		return;

2482 2483
	update_context_time(ctx);

2484 2485
	event = list_first_entry(&ctx->event_list,
				   struct perf_event, event_entry);
2486

2487 2488
	next_event = list_first_entry(&next_ctx->event_list,
					struct perf_event, event_entry);
2489

2490 2491
	while (&event->event_entry != &ctx->event_list &&
	       &next_event->event_entry != &next_ctx->event_list) {
2492

2493
		__perf_event_sync_stat(event, next_event);
2494

2495 2496
		event = list_next_entry(event, event_entry);
		next_event = list_next_entry(next_event, event_entry);
2497 2498 2499
	}
}

2500 2501
static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
					 struct task_struct *next)
T
Thomas Gleixner 已提交
2502
{
P
Peter Zijlstra 已提交
2503
	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2504
	struct perf_event_context *next_ctx;
2505
	struct perf_event_context *parent, *next_parent;
P
Peter Zijlstra 已提交
2506
	struct perf_cpu_context *cpuctx;
2507
	int do_switch = 1;
T
Thomas Gleixner 已提交
2508

P
Peter Zijlstra 已提交
2509 2510
	if (likely(!ctx))
		return;
2511

P
Peter Zijlstra 已提交
2512 2513
	cpuctx = __get_cpu_context(ctx);
	if (!cpuctx->task_ctx)
T
Thomas Gleixner 已提交
2514 2515
		return;

2516
	rcu_read_lock();
P
Peter Zijlstra 已提交
2517
	next_ctx = next->perf_event_ctxp[ctxn];
2518 2519 2520 2521 2522 2523 2524
	if (!next_ctx)
		goto unlock;

	parent = rcu_dereference(ctx->parent_ctx);
	next_parent = rcu_dereference(next_ctx->parent_ctx);

	/* If neither context have a parent context; they cannot be clones. */
2525
	if (!parent && !next_parent)
2526 2527 2528
		goto unlock;

	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2529 2530 2531 2532 2533 2534 2535 2536 2537
		/*
		 * Looks like the two contexts are clones, so we might be
		 * able to optimize the context switch.  We lock both
		 * contexts and check that they are clones under the
		 * lock (including re-checking that neither has been
		 * uncloned in the meantime).  It doesn't matter which
		 * order we take the locks because no other cpu could
		 * be trying to lock both of these tasks.
		 */
2538 2539
		raw_spin_lock(&ctx->lock);
		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2540
		if (context_equiv(ctx, next_ctx)) {
2541 2542
			/*
			 * XXX do we need a memory barrier of sorts
2543
			 * wrt to rcu_dereference() of perf_event_ctxp
2544
			 */
P
Peter Zijlstra 已提交
2545 2546
			task->perf_event_ctxp[ctxn] = next_ctx;
			next->perf_event_ctxp[ctxn] = ctx;
2547 2548
			ctx->task = next;
			next_ctx->task = task;
2549 2550 2551

			swap(ctx->task_ctx_data, next_ctx->task_ctx_data);

2552
			do_switch = 0;
2553

2554
			perf_event_sync_stat(ctx, next_ctx);
2555
		}
2556 2557
		raw_spin_unlock(&next_ctx->lock);
		raw_spin_unlock(&ctx->lock);
2558
	}
2559
unlock:
2560
	rcu_read_unlock();
2561

2562
	if (do_switch) {
2563
		raw_spin_lock(&ctx->lock);
2564
		ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2565
		cpuctx->task_ctx = NULL;
2566
		raw_spin_unlock(&ctx->lock);
2567
	}
T
Thomas Gleixner 已提交
2568 2569
}

2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619
void perf_sched_cb_dec(struct pmu *pmu)
{
	this_cpu_dec(perf_sched_cb_usages);
}

void perf_sched_cb_inc(struct pmu *pmu)
{
	this_cpu_inc(perf_sched_cb_usages);
}

/*
 * This function provides the context switch callback to the lower code
 * layer. It is invoked ONLY when the context switch callback is enabled.
 */
static void perf_pmu_sched_task(struct task_struct *prev,
				struct task_struct *next,
				bool sched_in)
{
	struct perf_cpu_context *cpuctx;
	struct pmu *pmu;
	unsigned long flags;

	if (prev == next)
		return;

	local_irq_save(flags);

	rcu_read_lock();

	list_for_each_entry_rcu(pmu, &pmus, entry) {
		if (pmu->sched_task) {
			cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);

			perf_ctx_lock(cpuctx, cpuctx->task_ctx);

			perf_pmu_disable(pmu);

			pmu->sched_task(cpuctx->task_ctx, sched_in);

			perf_pmu_enable(pmu);

			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
		}
	}

	rcu_read_unlock();

	local_irq_restore(flags);
}

P
Peter Zijlstra 已提交
2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633
#define for_each_task_context_nr(ctxn)					\
	for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)

/*
 * Called from scheduler to remove the events of the current task,
 * with interrupts disabled.
 *
 * We stop each event and update the event value in event->count.
 *
 * This does not protect us against NMI, but disable()
 * sets the disabled bit in the control field of event _before_
 * accessing the event control register. If a NMI hits, then it will
 * not restart the event.
 */
2634 2635
void __perf_event_task_sched_out(struct task_struct *task,
				 struct task_struct *next)
P
Peter Zijlstra 已提交
2636 2637 2638
{
	int ctxn;

2639 2640 2641
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(task, next, false);

P
Peter Zijlstra 已提交
2642 2643
	for_each_task_context_nr(ctxn)
		perf_event_context_sched_out(task, ctxn, next);
S
Stephane Eranian 已提交
2644 2645 2646 2647 2648 2649

	/*
	 * if cgroup events exist on this CPU, then we need
	 * to check if we have to switch out PMU state.
	 * cgroup event are system-wide mode only
	 */
2650
	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2651
		perf_cgroup_sched_out(task, next);
P
Peter Zijlstra 已提交
2652 2653
}

2654
static void task_ctx_sched_out(struct perf_event_context *ctx)
2655
{
P
Peter Zijlstra 已提交
2656
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2657

2658 2659
	if (!cpuctx->task_ctx)
		return;
2660 2661 2662 2663

	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
		return;

2664
	ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2665 2666 2667
	cpuctx->task_ctx = NULL;
}

2668 2669 2670 2671 2672 2673 2674
/*
 * Called with IRQs disabled
 */
static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
			      enum event_type_t event_type)
{
	ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2675 2676
}

2677
static void
2678
ctx_pinned_sched_in(struct perf_event_context *ctx,
2679
		    struct perf_cpu_context *cpuctx)
T
Thomas Gleixner 已提交
2680
{
2681
	struct perf_event *event;
T
Thomas Gleixner 已提交
2682

2683 2684
	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
		if (event->state <= PERF_EVENT_STATE_OFF)
2685
			continue;
2686
		if (!event_filter_match(event))
2687 2688
			continue;

S
Stephane Eranian 已提交
2689 2690 2691 2692
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

2693
		if (group_can_go_on(event, cpuctx, 1))
2694
			group_sched_in(event, cpuctx, ctx);
2695 2696 2697 2698 2699

		/*
		 * If this pinned group hasn't been scheduled,
		 * put it in error state.
		 */
2700 2701 2702
		if (event->state == PERF_EVENT_STATE_INACTIVE) {
			update_group_times(event);
			event->state = PERF_EVENT_STATE_ERROR;
2703
		}
2704
	}
2705 2706 2707 2708
}

static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
2709
		      struct perf_cpu_context *cpuctx)
2710 2711 2712
{
	struct perf_event *event;
	int can_add_hw = 1;
2713

2714 2715 2716
	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
		/* Ignore events in OFF or ERROR state */
		if (event->state <= PERF_EVENT_STATE_OFF)
2717
			continue;
2718 2719
		/*
		 * Listen to the 'cpu' scheduling filter constraint
2720
		 * of events:
2721
		 */
2722
		if (!event_filter_match(event))
T
Thomas Gleixner 已提交
2723 2724
			continue;

S
Stephane Eranian 已提交
2725 2726 2727 2728
		/* may need to reset tstamp_enabled */
		if (is_cgroup_event(event))
			perf_cgroup_mark_enabled(event, ctx);

P
Peter Zijlstra 已提交
2729
		if (group_can_go_on(event, cpuctx, can_add_hw)) {
2730
			if (group_sched_in(event, cpuctx, ctx))
2731
				can_add_hw = 0;
P
Peter Zijlstra 已提交
2732
		}
T
Thomas Gleixner 已提交
2733
	}
2734 2735 2736 2737 2738
}

static void
ctx_sched_in(struct perf_event_context *ctx,
	     struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2739 2740
	     enum event_type_t event_type,
	     struct task_struct *task)
2741
{
S
Stephane Eranian 已提交
2742
	u64 now;
2743
	int is_active = ctx->is_active;
S
Stephane Eranian 已提交
2744

2745
	ctx->is_active |= event_type;
2746
	if (likely(!ctx->nr_events))
2747
		return;
2748

S
Stephane Eranian 已提交
2749 2750
	now = perf_clock();
	ctx->timestamp = now;
2751
	perf_cgroup_set_timestamp(task, ctx);
2752 2753 2754 2755
	/*
	 * First go through the list and put on any pinned groups
	 * in order to give them the best chance of going on.
	 */
2756
	if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2757
		ctx_pinned_sched_in(ctx, cpuctx);
2758 2759

	/* Then walk through the lower prio flexible groups */
2760
	if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2761
		ctx_flexible_sched_in(ctx, cpuctx);
2762 2763
}

2764
static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
S
Stephane Eranian 已提交
2765 2766
			     enum event_type_t event_type,
			     struct task_struct *task)
2767 2768 2769
{
	struct perf_event_context *ctx = &cpuctx->ctx;

S
Stephane Eranian 已提交
2770
	ctx_sched_in(ctx, cpuctx, event_type, task);
2771 2772
}

S
Stephane Eranian 已提交
2773 2774
static void perf_event_context_sched_in(struct perf_event_context *ctx,
					struct task_struct *task)
2775
{
P
Peter Zijlstra 已提交
2776
	struct perf_cpu_context *cpuctx;
2777

P
Peter Zijlstra 已提交
2778
	cpuctx = __get_cpu_context(ctx);
2779 2780 2781
	if (cpuctx->task_ctx == ctx)
		return;

2782
	perf_ctx_lock(cpuctx, ctx);
P
Peter Zijlstra 已提交
2783
	perf_pmu_disable(ctx->pmu);
2784 2785 2786 2787 2788 2789 2790
	/*
	 * We want to keep the following priority order:
	 * cpu pinned (that don't need to move), task pinned,
	 * cpu flexible, task flexible.
	 */
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);

2791 2792
	if (ctx->nr_events)
		cpuctx->task_ctx = ctx;
2793

2794 2795
	perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);

2796 2797
	perf_pmu_enable(ctx->pmu);
	perf_ctx_unlock(cpuctx, ctx);
2798 2799
}

P
Peter Zijlstra 已提交
2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810
/*
 * Called from scheduler to add the events of the current task
 * with interrupts disabled.
 *
 * We restore the event value and then enable it.
 *
 * This does not protect us against NMI, but enable()
 * sets the enabled bit in the control field of event _before_
 * accessing the event control register. If a NMI hits, then it will
 * keep the event running.
 */
2811 2812
void __perf_event_task_sched_in(struct task_struct *prev,
				struct task_struct *task)
P
Peter Zijlstra 已提交
2813 2814 2815 2816 2817 2818 2819 2820 2821
{
	struct perf_event_context *ctx;
	int ctxn;

	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (likely(!ctx))
			continue;

S
Stephane Eranian 已提交
2822
		perf_event_context_sched_in(ctx, task);
P
Peter Zijlstra 已提交
2823
	}
S
Stephane Eranian 已提交
2824 2825 2826 2827 2828
	/*
	 * if cgroup events exist on this CPU, then we need
	 * to check if we have to switch in PMU state.
	 * cgroup event are system-wide mode only
	 */
2829
	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2830
		perf_cgroup_sched_in(prev, task);
2831

2832 2833
	if (__this_cpu_read(perf_sched_cb_usages))
		perf_pmu_sched_task(prev, task, true);
2834 2835
}

2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862
static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
{
	u64 frequency = event->attr.sample_freq;
	u64 sec = NSEC_PER_SEC;
	u64 divisor, dividend;

	int count_fls, nsec_fls, frequency_fls, sec_fls;

	count_fls = fls64(count);
	nsec_fls = fls64(nsec);
	frequency_fls = fls64(frequency);
	sec_fls = 30;

	/*
	 * We got @count in @nsec, with a target of sample_freq HZ
	 * the target period becomes:
	 *
	 *             @count * 10^9
	 * period = -------------------
	 *          @nsec * sample_freq
	 *
	 */

	/*
	 * Reduce accuracy by one bit such that @a and @b converge
	 * to a similar magnitude.
	 */
2863
#define REDUCE_FLS(a, b)		\
2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902
do {					\
	if (a##_fls > b##_fls) {	\
		a >>= 1;		\
		a##_fls--;		\
	} else {			\
		b >>= 1;		\
		b##_fls--;		\
	}				\
} while (0)

	/*
	 * Reduce accuracy until either term fits in a u64, then proceed with
	 * the other, so that finally we can do a u64/u64 division.
	 */
	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
		REDUCE_FLS(nsec, frequency);
		REDUCE_FLS(sec, count);
	}

	if (count_fls + sec_fls > 64) {
		divisor = nsec * frequency;

		while (count_fls + sec_fls > 64) {
			REDUCE_FLS(count, sec);
			divisor >>= 1;
		}

		dividend = count * sec;
	} else {
		dividend = count * sec;

		while (nsec_fls + frequency_fls > 64) {
			REDUCE_FLS(nsec, frequency);
			dividend >>= 1;
		}

		divisor = nsec * frequency;
	}

2903 2904 2905
	if (!divisor)
		return dividend;

2906 2907 2908
	return div64_u64(dividend, divisor);
}

2909 2910 2911
static DEFINE_PER_CPU(int, perf_throttled_count);
static DEFINE_PER_CPU(u64, perf_throttled_seq);

2912
static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2913
{
2914
	struct hw_perf_event *hwc = &event->hw;
2915
	s64 period, sample_period;
2916 2917
	s64 delta;

2918
	period = perf_calculate_period(event, nsec, count);
2919 2920 2921 2922 2923 2924 2925 2926 2927 2928

	delta = (s64)(period - hwc->sample_period);
	delta = (delta + 7) / 8; /* low pass filter */

	sample_period = hwc->sample_period + delta;

	if (!sample_period)
		sample_period = 1;

	hwc->sample_period = sample_period;
2929

2930
	if (local64_read(&hwc->period_left) > 8*sample_period) {
2931 2932 2933
		if (disable)
			event->pmu->stop(event, PERF_EF_UPDATE);

2934
		local64_set(&hwc->period_left, 0);
2935 2936 2937

		if (disable)
			event->pmu->start(event, PERF_EF_RELOAD);
2938
	}
2939 2940
}

2941 2942 2943 2944 2945 2946 2947
/*
 * combine freq adjustment with unthrottling to avoid two passes over the
 * events. At the same time, make sure, having freq events does not change
 * the rate of unthrottling as that would introduce bias.
 */
static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
					   int needs_unthr)
2948
{
2949 2950
	struct perf_event *event;
	struct hw_perf_event *hwc;
2951
	u64 now, period = TICK_NSEC;
2952
	s64 delta;
2953

2954 2955 2956 2957 2958 2959
	/*
	 * only need to iterate over all events iff:
	 * - context have events in frequency mode (needs freq adjust)
	 * - there are events to unthrottle on this cpu
	 */
	if (!(ctx->nr_freq || needs_unthr))
2960 2961
		return;

2962
	raw_spin_lock(&ctx->lock);
2963
	perf_pmu_disable(ctx->pmu);
2964

2965
	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2966
		if (event->state != PERF_EVENT_STATE_ACTIVE)
2967 2968
			continue;

2969
		if (!event_filter_match(event))
2970 2971
			continue;

2972 2973
		perf_pmu_disable(event->pmu);

2974
		hwc = &event->hw;
2975

2976
		if (hwc->interrupts == MAX_INTERRUPTS) {
2977
			hwc->interrupts = 0;
2978
			perf_log_throttle(event, 1);
P
Peter Zijlstra 已提交
2979
			event->pmu->start(event, 0);
2980 2981
		}

2982
		if (!event->attr.freq || !event->attr.sample_freq)
2983
			goto next;
2984

2985 2986 2987 2988 2989
		/*
		 * stop the event and update event->count
		 */
		event->pmu->stop(event, PERF_EF_UPDATE);

2990
		now = local64_read(&event->count);
2991 2992
		delta = now - hwc->freq_count_stamp;
		hwc->freq_count_stamp = now;
2993

2994 2995 2996
		/*
		 * restart the event
		 * reload only if value has changed
2997 2998 2999
		 * we have stopped the event so tell that
		 * to perf_adjust_period() to avoid stopping it
		 * twice.
3000
		 */
3001
		if (delta > 0)
3002
			perf_adjust_period(event, period, delta, false);
3003 3004

		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3005 3006
	next:
		perf_pmu_enable(event->pmu);
3007
	}
3008

3009
	perf_pmu_enable(ctx->pmu);
3010
	raw_spin_unlock(&ctx->lock);
3011 3012
}

3013
/*
3014
 * Round-robin a context's events:
3015
 */
3016
static void rotate_ctx(struct perf_event_context *ctx)
T
Thomas Gleixner 已提交
3017
{
3018 3019 3020 3021 3022 3023
	/*
	 * Rotate the first entry last of non-pinned groups. Rotation might be
	 * disabled by the inheritance code.
	 */
	if (!ctx->rotate_disable)
		list_rotate_left(&ctx->flexible_groups);
3024 3025
}

3026
static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3027
{
P
Peter Zijlstra 已提交
3028
	struct perf_event_context *ctx = NULL;
3029
	int rotate = 0;
3030

3031 3032 3033 3034
	if (cpuctx->ctx.nr_events) {
		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
			rotate = 1;
	}
3035

P
Peter Zijlstra 已提交
3036
	ctx = cpuctx->task_ctx;
3037 3038 3039 3040
	if (ctx && ctx->nr_events) {
		if (ctx->nr_events != ctx->nr_active)
			rotate = 1;
	}
3041

3042
	if (!rotate)
3043 3044
		goto done;

3045
	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
P
Peter Zijlstra 已提交
3046
	perf_pmu_disable(cpuctx->ctx.pmu);
3047

3048 3049 3050
	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
	if (ctx)
		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
T
Thomas Gleixner 已提交
3051

3052 3053 3054
	rotate_ctx(&cpuctx->ctx);
	if (ctx)
		rotate_ctx(ctx);
3055

3056
	perf_event_sched_in(cpuctx, ctx, current);
3057

3058 3059
	perf_pmu_enable(cpuctx->ctx.pmu);
	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3060
done:
3061 3062

	return rotate;
3063 3064
}

3065 3066 3067
#ifdef CONFIG_NO_HZ_FULL
bool perf_event_can_stop_tick(void)
{
3068
	if (atomic_read(&nr_freq_events) ||
3069
	    __this_cpu_read(perf_throttled_count))
3070
		return false;
3071 3072
	else
		return true;
3073 3074 3075
}
#endif

3076 3077
void perf_event_task_tick(void)
{
3078 3079
	struct list_head *head = this_cpu_ptr(&active_ctx_list);
	struct perf_event_context *ctx, *tmp;
3080
	int throttled;
3081

3082 3083
	WARN_ON(!irqs_disabled());

3084 3085 3086
	__this_cpu_inc(perf_throttled_seq);
	throttled = __this_cpu_xchg(perf_throttled_count, 0);

3087
	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3088
		perf_adjust_freq_unthr_context(ctx, throttled);
T
Thomas Gleixner 已提交
3089 3090
}

3091 3092 3093 3094 3095 3096 3097 3098 3099 3100
static int event_enable_on_exec(struct perf_event *event,
				struct perf_event_context *ctx)
{
	if (!event->attr.enable_on_exec)
		return 0;

	event->attr.enable_on_exec = 0;
	if (event->state >= PERF_EVENT_STATE_INACTIVE)
		return 0;

3101
	__perf_event_mark_enabled(event);
3102 3103 3104 3105

	return 1;
}

3106
/*
3107
 * Enable all of a task's events that have been marked enable-on-exec.
3108 3109
 * This expects task == current.
 */
P
Peter Zijlstra 已提交
3110
static void perf_event_enable_on_exec(struct perf_event_context *ctx)
3111
{
3112
	struct perf_event_context *clone_ctx = NULL;
3113
	struct perf_event *event;
3114 3115
	unsigned long flags;
	int enabled = 0;
3116
	int ret;
3117 3118

	local_irq_save(flags);
3119
	if (!ctx || !ctx->nr_events)
3120 3121
		goto out;

3122 3123 3124 3125 3126 3127 3128
	/*
	 * We must ctxsw out cgroup events to avoid conflict
	 * when invoking perf_task_event_sched_in() later on
	 * in this function. Otherwise we end up trying to
	 * ctxswin cgroup events which are already scheduled
	 * in.
	 */
3129
	perf_cgroup_sched_out(current, NULL);
3130

3131
	raw_spin_lock(&ctx->lock);
3132
	task_ctx_sched_out(ctx);
3133

3134
	list_for_each_entry(event, &ctx->event_list, event_entry) {
3135 3136 3137
		ret = event_enable_on_exec(event, ctx);
		if (ret)
			enabled = 1;
3138 3139 3140
	}

	/*
3141
	 * Unclone this context if we enabled any event.
3142
	 */
3143
	if (enabled)
3144
		clone_ctx = unclone_ctx(ctx);
3145

3146
	raw_spin_unlock(&ctx->lock);
3147

3148 3149 3150
	/*
	 * Also calls ctxswin for cgroup events, if any:
	 */
S
Stephane Eranian 已提交
3151
	perf_event_context_sched_in(ctx, ctx->task);
P
Peter Zijlstra 已提交
3152
out:
3153
	local_irq_restore(flags);
3154 3155 3156

	if (clone_ctx)
		put_ctx(clone_ctx);
3157 3158
}

3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174
void perf_event_exec(void)
{
	struct perf_event_context *ctx;
	int ctxn;

	rcu_read_lock();
	for_each_task_context_nr(ctxn) {
		ctx = current->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;

		perf_event_enable_on_exec(ctx);
	}
	rcu_read_unlock();
}

T
Thomas Gleixner 已提交
3175
/*
3176
 * Cross CPU call to read the hardware event
T
Thomas Gleixner 已提交
3177
 */
3178
static void __perf_event_read(void *info)
T
Thomas Gleixner 已提交
3179
{
3180 3181
	struct perf_event *event = info;
	struct perf_event_context *ctx = event->ctx;
P
Peter Zijlstra 已提交
3182
	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
I
Ingo Molnar 已提交
3183

3184 3185 3186 3187
	/*
	 * If this is a task context, we need to check whether it is
	 * the current task context of this cpu.  If not it has been
	 * scheduled out before the smp call arrived.  In that case
3188 3189
	 * event->count would have been updated to a recent sample
	 * when the event was scheduled out.
3190 3191 3192 3193
	 */
	if (ctx->task && cpuctx->task_ctx != ctx)
		return;

3194
	raw_spin_lock(&ctx->lock);
S
Stephane Eranian 已提交
3195
	if (ctx->is_active) {
3196
		update_context_time(ctx);
S
Stephane Eranian 已提交
3197 3198
		update_cgrp_time_from_event(event);
	}
3199
	update_event_times(event);
3200 3201
	if (event->state == PERF_EVENT_STATE_ACTIVE)
		event->pmu->read(event);
3202
	raw_spin_unlock(&ctx->lock);
T
Thomas Gleixner 已提交
3203 3204
}

P
Peter Zijlstra 已提交
3205 3206
static inline u64 perf_event_count(struct perf_event *event)
{
3207 3208 3209 3210
	if (event->pmu->count)
		return event->pmu->count(event);

	return __perf_event_count(event);
P
Peter Zijlstra 已提交
3211 3212
}

3213
static u64 perf_event_read(struct perf_event *event)
T
Thomas Gleixner 已提交
3214 3215
{
	/*
3216 3217
	 * If event is enabled and currently active on a CPU, update the
	 * value in the event structure:
T
Thomas Gleixner 已提交
3218
	 */
3219 3220 3221 3222
	if (event->state == PERF_EVENT_STATE_ACTIVE) {
		smp_call_function_single(event->oncpu,
					 __perf_event_read, event, 1);
	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
P
Peter Zijlstra 已提交
3223 3224 3225
		struct perf_event_context *ctx = event->ctx;
		unsigned long flags;

3226
		raw_spin_lock_irqsave(&ctx->lock, flags);
3227 3228 3229 3230 3231
		/*
		 * may read while context is not active
		 * (e.g., thread is blocked), in that case
		 * we cannot update context time
		 */
S
Stephane Eranian 已提交
3232
		if (ctx->is_active) {
3233
			update_context_time(ctx);
S
Stephane Eranian 已提交
3234 3235
			update_cgrp_time_from_event(event);
		}
3236
		update_event_times(event);
3237
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
T
Thomas Gleixner 已提交
3238 3239
	}

P
Peter Zijlstra 已提交
3240
	return perf_event_count(event);
T
Thomas Gleixner 已提交
3241 3242
}

3243
/*
3244
 * Initialize the perf_event context in a task_struct:
3245
 */
3246
static void __perf_event_init_context(struct perf_event_context *ctx)
3247
{
3248
	raw_spin_lock_init(&ctx->lock);
3249
	mutex_init(&ctx->mutex);
3250
	INIT_LIST_HEAD(&ctx->active_ctx_list);
3251 3252
	INIT_LIST_HEAD(&ctx->pinned_groups);
	INIT_LIST_HEAD(&ctx->flexible_groups);
3253 3254
	INIT_LIST_HEAD(&ctx->event_list);
	atomic_set(&ctx->refcount, 1);
3255
	INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270
}

static struct perf_event_context *
alloc_perf_context(struct pmu *pmu, struct task_struct *task)
{
	struct perf_event_context *ctx;

	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
	if (!ctx)
		return NULL;

	__perf_event_init_context(ctx);
	if (task) {
		ctx->task = task;
		get_task_struct(task);
T
Thomas Gleixner 已提交
3271
	}
3272 3273 3274
	ctx->pmu = pmu;

	return ctx;
3275 3276
}

3277 3278 3279 3280 3281
static struct task_struct *
find_lively_task_by_vpid(pid_t vpid)
{
	struct task_struct *task;
	int err;
T
Thomas Gleixner 已提交
3282 3283

	rcu_read_lock();
3284
	if (!vpid)
T
Thomas Gleixner 已提交
3285 3286
		task = current;
	else
3287
		task = find_task_by_vpid(vpid);
T
Thomas Gleixner 已提交
3288 3289 3290 3291 3292 3293 3294 3295
	if (task)
		get_task_struct(task);
	rcu_read_unlock();

	if (!task)
		return ERR_PTR(-ESRCH);

	/* Reuse ptrace permission checks for now. */
3296 3297 3298 3299
	err = -EACCES;
	if (!ptrace_may_access(task, PTRACE_MODE_READ))
		goto errout;

3300 3301 3302 3303 3304 3305 3306
	return task;
errout:
	put_task_struct(task);
	return ERR_PTR(err);

}

3307 3308 3309
/*
 * Returns a matching context with refcount and pincount.
 */
P
Peter Zijlstra 已提交
3310
static struct perf_event_context *
3311 3312
find_get_context(struct pmu *pmu, struct task_struct *task,
		struct perf_event *event)
T
Thomas Gleixner 已提交
3313
{
3314
	struct perf_event_context *ctx, *clone_ctx = NULL;
3315
	struct perf_cpu_context *cpuctx;
3316
	void *task_ctx_data = NULL;
3317
	unsigned long flags;
P
Peter Zijlstra 已提交
3318
	int ctxn, err;
3319
	int cpu = event->cpu;
T
Thomas Gleixner 已提交
3320

3321
	if (!task) {
3322
		/* Must be root to operate on a CPU event: */
3323
		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
T
Thomas Gleixner 已提交
3324 3325 3326
			return ERR_PTR(-EACCES);

		/*
3327
		 * We could be clever and allow to attach a event to an
T
Thomas Gleixner 已提交
3328 3329 3330
		 * offline CPU and activate it when the CPU comes up, but
		 * that's for later.
		 */
3331
		if (!cpu_online(cpu))
T
Thomas Gleixner 已提交
3332 3333
			return ERR_PTR(-ENODEV);

P
Peter Zijlstra 已提交
3334
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
T
Thomas Gleixner 已提交
3335
		ctx = &cpuctx->ctx;
3336
		get_ctx(ctx);
3337
		++ctx->pin_count;
T
Thomas Gleixner 已提交
3338 3339 3340 3341

		return ctx;
	}

P
Peter Zijlstra 已提交
3342 3343 3344 3345 3346
	err = -EINVAL;
	ctxn = pmu->task_ctx_nr;
	if (ctxn < 0)
		goto errout;

3347 3348 3349 3350 3351 3352 3353 3354
	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
		task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
		if (!task_ctx_data) {
			err = -ENOMEM;
			goto errout;
		}
	}

P
Peter Zijlstra 已提交
3355
retry:
P
Peter Zijlstra 已提交
3356
	ctx = perf_lock_task_context(task, ctxn, &flags);
3357
	if (ctx) {
3358
		clone_ctx = unclone_ctx(ctx);
3359
		++ctx->pin_count;
3360 3361 3362 3363 3364

		if (task_ctx_data && !ctx->task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}
3365
		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3366 3367 3368

		if (clone_ctx)
			put_ctx(clone_ctx);
3369
	} else {
3370
		ctx = alloc_perf_context(pmu, task);
3371 3372 3373
		err = -ENOMEM;
		if (!ctx)
			goto errout;
3374

3375 3376 3377 3378 3379
		if (task_ctx_data) {
			ctx->task_ctx_data = task_ctx_data;
			task_ctx_data = NULL;
		}

3380 3381 3382 3383 3384 3385 3386 3387 3388 3389
		err = 0;
		mutex_lock(&task->perf_event_mutex);
		/*
		 * If it has already passed perf_event_exit_task().
		 * we must see PF_EXITING, it takes this mutex too.
		 */
		if (task->flags & PF_EXITING)
			err = -ESRCH;
		else if (task->perf_event_ctxp[ctxn])
			err = -EAGAIN;
3390
		else {
3391
			get_ctx(ctx);
3392
			++ctx->pin_count;
3393
			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3394
		}
3395 3396 3397
		mutex_unlock(&task->perf_event_mutex);

		if (unlikely(err)) {
3398
			put_ctx(ctx);
3399 3400 3401 3402

			if (err == -EAGAIN)
				goto retry;
			goto errout;
3403 3404 3405
		}
	}

3406
	kfree(task_ctx_data);
T
Thomas Gleixner 已提交
3407
	return ctx;
3408

P
Peter Zijlstra 已提交
3409
errout:
3410
	kfree(task_ctx_data);
3411
	return ERR_PTR(err);
T
Thomas Gleixner 已提交
3412 3413
}

L
Li Zefan 已提交
3414
static void perf_event_free_filter(struct perf_event *event);
3415
static void perf_event_free_bpf_prog(struct perf_event *event);
L
Li Zefan 已提交
3416

3417
static void free_event_rcu(struct rcu_head *head)
P
Peter Zijlstra 已提交
3418
{
3419
	struct perf_event *event;
P
Peter Zijlstra 已提交
3420

3421 3422 3423
	event = container_of(head, struct perf_event, rcu_head);
	if (event->ns)
		put_pid_ns(event->ns);
L
Li Zefan 已提交
3424
	perf_event_free_filter(event);
3425
	perf_event_free_bpf_prog(event);
3426
	kfree(event);
P
Peter Zijlstra 已提交
3427 3428
}

3429 3430
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb);
3431

3432
static void unaccount_event_cpu(struct perf_event *event, int cpu)
3433
{
3434 3435 3436 3437 3438 3439
	if (event->parent)
		return;

	if (is_cgroup_event(event))
		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
}
3440

3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453
static void unaccount_event(struct perf_event *event)
{
	if (event->parent)
		return;

	if (event->attach_state & PERF_ATTACH_TASK)
		static_key_slow_dec_deferred(&perf_sched_events);
	if (event->attr.mmap || event->attr.mmap_data)
		atomic_dec(&nr_mmap_events);
	if (event->attr.comm)
		atomic_dec(&nr_comm_events);
	if (event->attr.task)
		atomic_dec(&nr_task_events);
3454 3455
	if (event->attr.freq)
		atomic_dec(&nr_freq_events);
3456 3457 3458 3459 3460 3461 3462
	if (is_cgroup_event(event))
		static_key_slow_dec_deferred(&perf_sched_events);
	if (has_branch_stack(event))
		static_key_slow_dec_deferred(&perf_sched_events);

	unaccount_event_cpu(event, event->cpu);
}
3463

3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548
/*
 * The following implement mutual exclusion of events on "exclusive" pmus
 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
 * at a time, so we disallow creating events that might conflict, namely:
 *
 *  1) cpu-wide events in the presence of per-task events,
 *  2) per-task events in the presence of cpu-wide events,
 *  3) two matching events on the same context.
 *
 * The former two cases are handled in the allocation path (perf_event_alloc(),
 * __free_event()), the latter -- before the first perf_install_in_context().
 */
static int exclusive_event_init(struct perf_event *event)
{
	struct pmu *pmu = event->pmu;

	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
		return 0;

	/*
	 * Prevent co-existence of per-task and cpu-wide events on the
	 * same exclusive pmu.
	 *
	 * Negative pmu::exclusive_cnt means there are cpu-wide
	 * events on this "exclusive" pmu, positive means there are
	 * per-task events.
	 *
	 * Since this is called in perf_event_alloc() path, event::ctx
	 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
	 * to mean "per-task event", because unlike other attach states it
	 * never gets cleared.
	 */
	if (event->attach_state & PERF_ATTACH_TASK) {
		if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
			return -EBUSY;
	} else {
		if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
			return -EBUSY;
	}

	return 0;
}

static void exclusive_event_destroy(struct perf_event *event)
{
	struct pmu *pmu = event->pmu;

	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
		return;

	/* see comment in exclusive_event_init() */
	if (event->attach_state & PERF_ATTACH_TASK)
		atomic_dec(&pmu->exclusive_cnt);
	else
		atomic_inc(&pmu->exclusive_cnt);
}

static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
{
	if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
	    (e1->cpu == e2->cpu ||
	     e1->cpu == -1 ||
	     e2->cpu == -1))
		return true;
	return false;
}

/* Called under the same ctx::mutex as perf_install_in_context() */
static bool exclusive_event_installable(struct perf_event *event,
					struct perf_event_context *ctx)
{
	struct perf_event *iter_event;
	struct pmu *pmu = event->pmu;

	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
		return true;

	list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
		if (exclusive_event_match(iter_event, event))
			return false;
	}

	return true;
}

3549 3550
static void __free_event(struct perf_event *event)
{
3551
	if (!event->parent) {
3552 3553
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
			put_callchain_buffers();
3554
	}
3555

3556 3557 3558 3559 3560 3561
	if (event->destroy)
		event->destroy(event);

	if (event->ctx)
		put_ctx(event->ctx);

3562 3563
	if (event->pmu) {
		exclusive_event_destroy(event);
3564
		module_put(event->pmu->module);
3565
	}
3566

3567 3568
	call_rcu(&event->rcu_head, free_event_rcu);
}
P
Peter Zijlstra 已提交
3569 3570

static void _free_event(struct perf_event *event)
3571
{
3572
	irq_work_sync(&event->pending);
3573

3574
	unaccount_event(event);
3575

3576
	if (event->rb) {
3577 3578 3579 3580 3581 3582 3583
		/*
		 * Can happen when we close an event with re-directed output.
		 *
		 * Since we have a 0 refcount, perf_mmap_close() will skip
		 * over us; possibly making our ring_buffer_put() the last.
		 */
		mutex_lock(&event->mmap_mutex);
3584
		ring_buffer_attach(event, NULL);
3585
		mutex_unlock(&event->mmap_mutex);
3586 3587
	}

S
Stephane Eranian 已提交
3588 3589 3590
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);

3591
	__free_event(event);
3592 3593
}

P
Peter Zijlstra 已提交
3594 3595 3596 3597 3598
/*
 * Used to free events which have a known refcount of 1, such as in error paths
 * where the event isn't exposed yet and inherited events.
 */
static void free_event(struct perf_event *event)
T
Thomas Gleixner 已提交
3599
{
P
Peter Zijlstra 已提交
3600 3601 3602 3603 3604 3605
	if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
				"unexpected event refcount: %ld; ptr=%p\n",
				atomic_long_read(&event->refcount), event)) {
		/* leak to avoid use-after-free */
		return;
	}
T
Thomas Gleixner 已提交
3606

P
Peter Zijlstra 已提交
3607
	_free_event(event);
T
Thomas Gleixner 已提交
3608 3609
}

3610
/*
3611
 * Remove user event from the owner task.
3612
 */
3613
static void perf_remove_from_owner(struct perf_event *event)
3614
{
P
Peter Zijlstra 已提交
3615
	struct task_struct *owner;
3616

P
Peter Zijlstra 已提交
3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636
	rcu_read_lock();
	owner = ACCESS_ONCE(event->owner);
	/*
	 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
	 * !owner it means the list deletion is complete and we can indeed
	 * free this event, otherwise we need to serialize on
	 * owner->perf_event_mutex.
	 */
	smp_read_barrier_depends();
	if (owner) {
		/*
		 * Since delayed_put_task_struct() also drops the last
		 * task reference we can safely take a new reference
		 * while holding the rcu_read_lock().
		 */
		get_task_struct(owner);
	}
	rcu_read_unlock();

	if (owner) {
P
Peter Zijlstra 已提交
3637 3638 3639 3640 3641 3642 3643 3644 3645 3646
		/*
		 * If we're here through perf_event_exit_task() we're already
		 * holding ctx->mutex which would be an inversion wrt. the
		 * normal lock order.
		 *
		 * However we can safely take this lock because its the child
		 * ctx->mutex.
		 */
		mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);

P
Peter Zijlstra 已提交
3647 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657
		/*
		 * We have to re-check the event->owner field, if it is cleared
		 * we raced with perf_event_exit_task(), acquiring the mutex
		 * ensured they're done, and we can proceed with freeing the
		 * event.
		 */
		if (event->owner)
			list_del_init(&event->owner_entry);
		mutex_unlock(&owner->perf_event_mutex);
		put_task_struct(owner);
	}
3658 3659 3660 3661 3662 3663 3664
}

/*
 * Called when the last reference to the file is gone.
 */
static void put_event(struct perf_event *event)
{
P
Peter Zijlstra 已提交
3665
	struct perf_event_context *ctx;
3666 3667 3668 3669 3670 3671

	if (!atomic_long_dec_and_test(&event->refcount))
		return;

	if (!is_kernel_event(event))
		perf_remove_from_owner(event);
P
Peter Zijlstra 已提交
3672

P
Peter Zijlstra 已提交
3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684
	/*
	 * There are two ways this annotation is useful:
	 *
	 *  1) there is a lock recursion from perf_event_exit_task
	 *     see the comment there.
	 *
	 *  2) there is a lock-inversion with mmap_sem through
	 *     perf_event_read_group(), which takes faults while
	 *     holding ctx->mutex, however this is called after
	 *     the last filedesc died, so there is no possibility
	 *     to trigger the AB-BA case.
	 */
P
Peter Zijlstra 已提交
3685 3686
	ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
	WARN_ON_ONCE(ctx->parent_ctx);
P
Peter Zijlstra 已提交
3687
	perf_remove_from_context(event, true);
L
Leon Yu 已提交
3688
	perf_event_ctx_unlock(event, ctx);
P
Peter Zijlstra 已提交
3689 3690

	_free_event(event);
3691 3692
}

P
Peter Zijlstra 已提交
3693 3694 3695 3696 3697 3698 3699
int perf_event_release_kernel(struct perf_event *event)
{
	put_event(event);
	return 0;
}
EXPORT_SYMBOL_GPL(perf_event_release_kernel);

3700 3701 3702 3703
static int perf_release(struct inode *inode, struct file *file)
{
	put_event(file->private_data);
	return 0;
3704 3705
}

3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741
/*
 * Remove all orphanes events from the context.
 */
static void orphans_remove_work(struct work_struct *work)
{
	struct perf_event_context *ctx;
	struct perf_event *event, *tmp;

	ctx = container_of(work, struct perf_event_context,
			   orphans_remove.work);

	mutex_lock(&ctx->mutex);
	list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
		struct perf_event *parent_event = event->parent;

		if (!is_orphaned_child(event))
			continue;

		perf_remove_from_context(event, true);

		mutex_lock(&parent_event->child_mutex);
		list_del_init(&event->child_list);
		mutex_unlock(&parent_event->child_mutex);

		free_event(event);
		put_event(parent_event);
	}

	raw_spin_lock_irq(&ctx->lock);
	ctx->orphans_remove_sched = false;
	raw_spin_unlock_irq(&ctx->lock);
	mutex_unlock(&ctx->mutex);

	put_ctx(ctx);
}

3742
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3743
{
3744
	struct perf_event *child;
3745 3746
	u64 total = 0;

3747 3748 3749
	*enabled = 0;
	*running = 0;

3750
	mutex_lock(&event->child_mutex);
3751
	total += perf_event_read(event);
3752 3753 3754 3755 3756 3757
	*enabled += event->total_time_enabled +
			atomic64_read(&event->child_total_time_enabled);
	*running += event->total_time_running +
			atomic64_read(&event->child_total_time_running);

	list_for_each_entry(child, &event->child_list, child_list) {
3758
		total += perf_event_read(child);
3759 3760 3761
		*enabled += child->total_time_enabled;
		*running += child->total_time_running;
	}
3762
	mutex_unlock(&event->child_mutex);
3763 3764 3765

	return total;
}
3766
EXPORT_SYMBOL_GPL(perf_event_read_value);
3767

3768
static int perf_event_read_group(struct perf_event *event,
3769 3770
				   u64 read_format, char __user *buf)
{
3771
	struct perf_event *leader = event->group_leader, *sub;
3772
	struct perf_event_context *ctx = leader->ctx;
P
Peter Zijlstra 已提交
3773
	int n = 0, size = 0, ret;
3774
	u64 count, enabled, running;
P
Peter Zijlstra 已提交
3775 3776 3777
	u64 values[5];

	lockdep_assert_held(&ctx->mutex);
3778

3779
	count = perf_event_read_value(leader, &enabled, &running);
3780 3781

	values[n++] = 1 + leader->nr_siblings;
3782 3783 3784 3785
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		values[n++] = enabled;
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		values[n++] = running;
3786 3787 3788
	values[n++] = count;
	if (read_format & PERF_FORMAT_ID)
		values[n++] = primary_event_id(leader);
3789 3790 3791 3792

	size = n * sizeof(u64);

	if (copy_to_user(buf, values, size))
P
Peter Zijlstra 已提交
3793
		return -EFAULT;
3794

3795
	ret = size;
3796

3797
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3798
		n = 0;
3799

3800
		values[n++] = perf_event_read_value(sub, &enabled, &running);
3801 3802 3803 3804 3805
		if (read_format & PERF_FORMAT_ID)
			values[n++] = primary_event_id(sub);

		size = n * sizeof(u64);

3806
		if (copy_to_user(buf + ret, values, size)) {
P
Peter Zijlstra 已提交
3807
			return -EFAULT;
3808
		}
3809 3810

		ret += size;
3811 3812
	}

3813
	return ret;
3814 3815
}

3816
static int perf_event_read_one(struct perf_event *event,
3817 3818
				 u64 read_format, char __user *buf)
{
3819
	u64 enabled, running;
3820 3821 3822
	u64 values[4];
	int n = 0;

3823 3824 3825 3826 3827
	values[n++] = perf_event_read_value(event, &enabled, &running);
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		values[n++] = enabled;
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		values[n++] = running;
3828
	if (read_format & PERF_FORMAT_ID)
3829
		values[n++] = primary_event_id(event);
3830 3831 3832 3833 3834 3835 3836

	if (copy_to_user(buf, values, n * sizeof(u64)))
		return -EFAULT;

	return n * sizeof(u64);
}

3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849
static bool is_event_hup(struct perf_event *event)
{
	bool no_children;

	if (event->state != PERF_EVENT_STATE_EXIT)
		return false;

	mutex_lock(&event->child_mutex);
	no_children = list_empty(&event->child_list);
	mutex_unlock(&event->child_mutex);
	return no_children;
}

T
Thomas Gleixner 已提交
3850
/*
3851
 * Read the performance event - simple non blocking version for now
T
Thomas Gleixner 已提交
3852 3853
 */
static ssize_t
3854
perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
T
Thomas Gleixner 已提交
3855
{
3856
	u64 read_format = event->attr.read_format;
3857
	int ret;
T
Thomas Gleixner 已提交
3858

3859
	/*
3860
	 * Return end-of-file for a read on a event that is in
3861 3862 3863
	 * error state (i.e. because it was pinned but it couldn't be
	 * scheduled on to the CPU at some point).
	 */
3864
	if (event->state == PERF_EVENT_STATE_ERROR)
3865 3866
		return 0;

3867
	if (count < event->read_size)
3868 3869
		return -ENOSPC;

3870
	WARN_ON_ONCE(event->ctx->parent_ctx);
3871
	if (read_format & PERF_FORMAT_GROUP)
3872
		ret = perf_event_read_group(event, read_format, buf);
3873
	else
3874
		ret = perf_event_read_one(event, read_format, buf);
T
Thomas Gleixner 已提交
3875

3876
	return ret;
T
Thomas Gleixner 已提交
3877 3878 3879 3880 3881
}

static ssize_t
perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
3882
	struct perf_event *event = file->private_data;
P
Peter Zijlstra 已提交
3883 3884
	struct perf_event_context *ctx;
	int ret;
T
Thomas Gleixner 已提交
3885

P
Peter Zijlstra 已提交
3886 3887 3888 3889 3890
	ctx = perf_event_ctx_lock(event);
	ret = perf_read_hw(event, buf, count);
	perf_event_ctx_unlock(event, ctx);

	return ret;
T
Thomas Gleixner 已提交
3891 3892 3893 3894
}

static unsigned int perf_poll(struct file *file, poll_table *wait)
{
3895
	struct perf_event *event = file->private_data;
3896
	struct ring_buffer *rb;
3897
	unsigned int events = POLLHUP;
P
Peter Zijlstra 已提交
3898

3899
	poll_wait(file, &event->waitq, wait);
3900

3901
	if (is_event_hup(event))
3902
		return events;
P
Peter Zijlstra 已提交
3903

3904
	/*
3905 3906
	 * Pin the event->rb by taking event->mmap_mutex; otherwise
	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3907 3908
	 */
	mutex_lock(&event->mmap_mutex);
3909 3910
	rb = event->rb;
	if (rb)
3911
		events = atomic_xchg(&rb->poll, 0);
3912
	mutex_unlock(&event->mmap_mutex);
T
Thomas Gleixner 已提交
3913 3914 3915
	return events;
}

P
Peter Zijlstra 已提交
3916
static void _perf_event_reset(struct perf_event *event)
3917
{
3918
	(void)perf_event_read(event);
3919
	local64_set(&event->count, 0);
3920
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
3921 3922
}

3923
/*
3924 3925 3926 3927
 * Holding the top-level event's child_mutex means that any
 * descendant process that has inherited this event will block
 * in sync_child_event if it goes to exit, thus satisfying the
 * task existence requirements of perf_event_enable/disable.
3928
 */
3929 3930
static void perf_event_for_each_child(struct perf_event *event,
					void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
3931
{
3932
	struct perf_event *child;
P
Peter Zijlstra 已提交
3933

3934
	WARN_ON_ONCE(event->ctx->parent_ctx);
P
Peter Zijlstra 已提交
3935

3936 3937 3938
	mutex_lock(&event->child_mutex);
	func(event);
	list_for_each_entry(child, &event->child_list, child_list)
P
Peter Zijlstra 已提交
3939
		func(child);
3940
	mutex_unlock(&event->child_mutex);
P
Peter Zijlstra 已提交
3941 3942
}

3943 3944
static void perf_event_for_each(struct perf_event *event,
				  void (*func)(struct perf_event *))
P
Peter Zijlstra 已提交
3945
{
3946 3947
	struct perf_event_context *ctx = event->ctx;
	struct perf_event *sibling;
P
Peter Zijlstra 已提交
3948

P
Peter Zijlstra 已提交
3949 3950
	lockdep_assert_held(&ctx->mutex);

3951
	event = event->group_leader;
3952

3953 3954
	perf_event_for_each_child(event, func);
	list_for_each_entry(sibling, &event->sibling_list, group_entry)
3955
		perf_event_for_each_child(sibling, func);
3956 3957
}

3958
static int perf_event_period(struct perf_event *event, u64 __user *arg)
3959
{
3960
	struct perf_event_context *ctx = event->ctx;
3961
	int ret = 0, active;
3962 3963
	u64 value;

3964
	if (!is_sampling_event(event))
3965 3966
		return -EINVAL;

3967
	if (copy_from_user(&value, arg, sizeof(value)))
3968 3969 3970 3971 3972
		return -EFAULT;

	if (!value)
		return -EINVAL;

3973
	raw_spin_lock_irq(&ctx->lock);
3974 3975
	if (event->attr.freq) {
		if (value > sysctl_perf_event_sample_rate) {
3976 3977 3978 3979
			ret = -EINVAL;
			goto unlock;
		}

3980
		event->attr.sample_freq = value;
3981
	} else {
3982 3983
		event->attr.sample_period = value;
		event->hw.sample_period = value;
3984
	}
3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998

	active = (event->state == PERF_EVENT_STATE_ACTIVE);
	if (active) {
		perf_pmu_disable(ctx->pmu);
		event->pmu->stop(event, PERF_EF_UPDATE);
	}

	local64_set(&event->hw.period_left, 0);

	if (active) {
		event->pmu->start(event, PERF_EF_RELOAD);
		perf_pmu_enable(ctx->pmu);
	}

3999
unlock:
4000
	raw_spin_unlock_irq(&ctx->lock);
4001 4002 4003 4004

	return ret;
}

4005 4006
static const struct file_operations perf_fops;

4007
static inline int perf_fget_light(int fd, struct fd *p)
4008
{
4009 4010 4011
	struct fd f = fdget(fd);
	if (!f.file)
		return -EBADF;
4012

4013 4014 4015
	if (f.file->f_op != &perf_fops) {
		fdput(f);
		return -EBADF;
4016
	}
4017 4018
	*p = f;
	return 0;
4019 4020 4021 4022
}

static int perf_event_set_output(struct perf_event *event,
				 struct perf_event *output_event);
L
Li Zefan 已提交
4023
static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4024
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4025

P
Peter Zijlstra 已提交
4026
static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4027
{
4028
	void (*func)(struct perf_event *);
P
Peter Zijlstra 已提交
4029
	u32 flags = arg;
4030 4031

	switch (cmd) {
4032
	case PERF_EVENT_IOC_ENABLE:
P
Peter Zijlstra 已提交
4033
		func = _perf_event_enable;
4034
		break;
4035
	case PERF_EVENT_IOC_DISABLE:
P
Peter Zijlstra 已提交
4036
		func = _perf_event_disable;
4037
		break;
4038
	case PERF_EVENT_IOC_RESET:
P
Peter Zijlstra 已提交
4039
		func = _perf_event_reset;
4040
		break;
P
Peter Zijlstra 已提交
4041

4042
	case PERF_EVENT_IOC_REFRESH:
P
Peter Zijlstra 已提交
4043
		return _perf_event_refresh(event, arg);
4044

4045 4046
	case PERF_EVENT_IOC_PERIOD:
		return perf_event_period(event, (u64 __user *)arg);
4047

4048 4049 4050 4051 4052 4053 4054 4055 4056
	case PERF_EVENT_IOC_ID:
	{
		u64 id = primary_event_id(event);

		if (copy_to_user((void __user *)arg, &id, sizeof(id)))
			return -EFAULT;
		return 0;
	}

4057
	case PERF_EVENT_IOC_SET_OUTPUT:
4058 4059 4060
	{
		int ret;
		if (arg != -1) {
4061 4062 4063 4064 4065 4066 4067 4068 4069 4070
			struct perf_event *output_event;
			struct fd output;
			ret = perf_fget_light(arg, &output);
			if (ret)
				return ret;
			output_event = output.file->private_data;
			ret = perf_event_set_output(event, output_event);
			fdput(output);
		} else {
			ret = perf_event_set_output(event, NULL);
4071 4072 4073
		}
		return ret;
	}
4074

L
Li Zefan 已提交
4075 4076 4077
	case PERF_EVENT_IOC_SET_FILTER:
		return perf_event_set_filter(event, (void __user *)arg);

4078 4079 4080
	case PERF_EVENT_IOC_SET_BPF:
		return perf_event_set_bpf_prog(event, arg);

4081
	default:
P
Peter Zijlstra 已提交
4082
		return -ENOTTY;
4083
	}
P
Peter Zijlstra 已提交
4084 4085

	if (flags & PERF_IOC_FLAG_GROUP)
4086
		perf_event_for_each(event, func);
P
Peter Zijlstra 已提交
4087
	else
4088
		perf_event_for_each_child(event, func);
P
Peter Zijlstra 已提交
4089 4090

	return 0;
4091 4092
}

P
Peter Zijlstra 已提交
4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105
static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct perf_event *event = file->private_data;
	struct perf_event_context *ctx;
	long ret;

	ctx = perf_event_ctx_lock(event);
	ret = _perf_ioctl(event, cmd, arg);
	perf_event_ctx_unlock(event, ctx);

	return ret;
}

P
Pawel Moll 已提交
4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125
#ifdef CONFIG_COMPAT
static long perf_compat_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	switch (_IOC_NR(cmd)) {
	case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
	case _IOC_NR(PERF_EVENT_IOC_ID):
		/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
			cmd &= ~IOCSIZE_MASK;
			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
		}
		break;
	}
	return perf_ioctl(file, cmd, arg);
}
#else
# define perf_compat_ioctl NULL
#endif

4126
int perf_event_task_enable(void)
4127
{
P
Peter Zijlstra 已提交
4128
	struct perf_event_context *ctx;
4129
	struct perf_event *event;
4130

4131
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4132 4133 4134 4135 4136
	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
		ctx = perf_event_ctx_lock(event);
		perf_event_for_each_child(event, _perf_event_enable);
		perf_event_ctx_unlock(event, ctx);
	}
4137
	mutex_unlock(&current->perf_event_mutex);
4138 4139 4140 4141

	return 0;
}

4142
int perf_event_task_disable(void)
4143
{
P
Peter Zijlstra 已提交
4144
	struct perf_event_context *ctx;
4145
	struct perf_event *event;
4146

4147
	mutex_lock(&current->perf_event_mutex);
P
Peter Zijlstra 已提交
4148 4149 4150 4151 4152
	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
		ctx = perf_event_ctx_lock(event);
		perf_event_for_each_child(event, _perf_event_disable);
		perf_event_ctx_unlock(event, ctx);
	}
4153
	mutex_unlock(&current->perf_event_mutex);
4154 4155 4156 4157

	return 0;
}

4158
static int perf_event_index(struct perf_event *event)
4159
{
P
Peter Zijlstra 已提交
4160 4161 4162
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;

4163
	if (event->state != PERF_EVENT_STATE_ACTIVE)
4164 4165
		return 0;

4166
	return event->pmu->event_idx(event);
4167 4168
}

4169
static void calc_timer_values(struct perf_event *event,
4170
				u64 *now,
4171 4172
				u64 *enabled,
				u64 *running)
4173
{
4174
	u64 ctx_time;
4175

4176 4177
	*now = perf_clock();
	ctx_time = event->shadow_ctx_time + *now;
4178 4179 4180 4181
	*enabled = ctx_time - event->tstamp_enabled;
	*running = ctx_time - event->tstamp_running;
}

4182 4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196
static void perf_event_init_userpage(struct perf_event *event)
{
	struct perf_event_mmap_page *userpg;
	struct ring_buffer *rb;

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

	userpg = rb->user_page;

	/* Allow new userspace to detect that bit 0 is deprecated */
	userpg->cap_bit0_is_deprecated = 1;
	userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4197 4198
	userpg->data_offset = PAGE_SIZE;
	userpg->data_size = perf_data_size(rb);
4199 4200 4201 4202 4203

unlock:
	rcu_read_unlock();
}

4204 4205
void __weak arch_perf_update_userpage(
	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4206 4207 4208
{
}

4209 4210 4211 4212 4213
/*
 * Callers need to ensure there can be no nesting of this function, otherwise
 * the seqlock logic goes bad. We can not serialize this because the arch
 * code calls this from NMI context.
 */
4214
void perf_event_update_userpage(struct perf_event *event)
4215
{
4216
	struct perf_event_mmap_page *userpg;
4217
	struct ring_buffer *rb;
4218
	u64 enabled, running, now;
4219 4220

	rcu_read_lock();
4221 4222 4223 4224
	rb = rcu_dereference(event->rb);
	if (!rb)
		goto unlock;

4225 4226 4227 4228 4229 4230 4231 4232 4233
	/*
	 * compute total_time_enabled, total_time_running
	 * based on snapshot values taken when the event
	 * was last scheduled in.
	 *
	 * we cannot simply called update_context_time()
	 * because of locking issue as we can be called in
	 * NMI context
	 */
4234
	calc_timer_values(event, &now, &enabled, &running);
4235

4236
	userpg = rb->user_page;
4237 4238 4239 4240 4241
	/*
	 * Disable preemption so as to not let the corresponding user-space
	 * spin too long if we get preempted.
	 */
	preempt_disable();
4242
	++userpg->lock;
4243
	barrier();
4244
	userpg->index = perf_event_index(event);
P
Peter Zijlstra 已提交
4245
	userpg->offset = perf_event_count(event);
4246
	if (userpg->index)
4247
		userpg->offset -= local64_read(&event->hw.prev_count);
4248

4249
	userpg->time_enabled = enabled +
4250
			atomic64_read(&event->child_total_time_enabled);
4251

4252
	userpg->time_running = running +
4253
			atomic64_read(&event->child_total_time_running);
4254

4255
	arch_perf_update_userpage(event, userpg, now);
4256

4257
	barrier();
4258
	++userpg->lock;
4259
	preempt_enable();
4260
unlock:
4261
	rcu_read_unlock();
4262 4263
}

4264 4265 4266
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct perf_event *event = vma->vm_file->private_data;
4267
	struct ring_buffer *rb;
4268 4269 4270 4271 4272 4273 4274 4275 4276
	int ret = VM_FAULT_SIGBUS;

	if (vmf->flags & FAULT_FLAG_MKWRITE) {
		if (vmf->pgoff == 0)
			ret = 0;
		return ret;
	}

	rcu_read_lock();
4277 4278
	rb = rcu_dereference(event->rb);
	if (!rb)
4279 4280 4281 4282 4283
		goto unlock;

	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
		goto unlock;

4284
	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298
	if (!vmf->page)
		goto unlock;

	get_page(vmf->page);
	vmf->page->mapping = vma->vm_file->f_mapping;
	vmf->page->index   = vmf->pgoff;

	ret = 0;
unlock:
	rcu_read_unlock();

	return ret;
}

4299 4300 4301
static void ring_buffer_attach(struct perf_event *event,
			       struct ring_buffer *rb)
{
4302
	struct ring_buffer *old_rb = NULL;
4303 4304
	unsigned long flags;

4305 4306 4307 4308 4309 4310
	if (event->rb) {
		/*
		 * Should be impossible, we set this when removing
		 * event->rb_entry and wait/clear when adding event->rb_entry.
		 */
		WARN_ON_ONCE(event->rcu_pending);
4311

4312 4313 4314
		old_rb = event->rb;
		event->rcu_batches = get_state_synchronize_rcu();
		event->rcu_pending = 1;
4315

4316 4317 4318 4319
		spin_lock_irqsave(&old_rb->event_lock, flags);
		list_del_rcu(&event->rb_entry);
		spin_unlock_irqrestore(&old_rb->event_lock, flags);
	}
4320

4321 4322 4323 4324
	if (event->rcu_pending && rb) {
		cond_synchronize_rcu(event->rcu_batches);
		event->rcu_pending = 0;
	}
4325

4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342
	if (rb) {
		spin_lock_irqsave(&rb->event_lock, flags);
		list_add_rcu(&event->rb_entry, &rb->event_list);
		spin_unlock_irqrestore(&rb->event_lock, flags);
	}

	rcu_assign_pointer(event->rb, rb);

	if (old_rb) {
		ring_buffer_put(old_rb);
		/*
		 * Since we detached before setting the new rb, so that we
		 * could attach the new rb, we could have missed a wakeup.
		 * Provide it now.
		 */
		wake_up_all(&event->waitq);
	}
4343 4344 4345 4346 4347 4348 4349 4350
}

static void ring_buffer_wakeup(struct perf_event *event)
{
	struct ring_buffer *rb;

	rcu_read_lock();
	rb = rcu_dereference(event->rb);
4351 4352 4353 4354
	if (rb) {
		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
			wake_up_all(&event->waitq);
	}
4355 4356 4357
	rcu_read_unlock();
}

4358
static void rb_free_rcu(struct rcu_head *rcu_head)
4359
{
4360
	struct ring_buffer *rb;
4361

4362 4363
	rb = container_of(rcu_head, struct ring_buffer, rcu_head);
	rb_free(rb);
4364 4365
}

4366
struct ring_buffer *ring_buffer_get(struct perf_event *event)
4367
{
4368
	struct ring_buffer *rb;
4369

4370
	rcu_read_lock();
4371 4372 4373 4374
	rb = rcu_dereference(event->rb);
	if (rb) {
		if (!atomic_inc_not_zero(&rb->refcount))
			rb = NULL;
4375 4376 4377
	}
	rcu_read_unlock();

4378
	return rb;
4379 4380
}

4381
void ring_buffer_put(struct ring_buffer *rb)
4382
{
4383
	if (!atomic_dec_and_test(&rb->refcount))
4384
		return;
4385

4386
	WARN_ON_ONCE(!list_empty(&rb->event_list));
4387

4388
	call_rcu(&rb->rcu_head, rb_free_rcu);
4389 4390 4391 4392
}

static void perf_mmap_open(struct vm_area_struct *vma)
{
4393
	struct perf_event *event = vma->vm_file->private_data;
4394

4395
	atomic_inc(&event->mmap_count);
4396
	atomic_inc(&event->rb->mmap_count);
4397

4398 4399 4400
	if (vma->vm_pgoff)
		atomic_inc(&event->rb->aux_mmap_count);

4401 4402
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);
4403 4404
}

4405 4406 4407 4408 4409 4410 4411 4412
/*
 * A buffer can be mmap()ed multiple times; either directly through the same
 * event, or through other events by use of perf_event_set_output().
 *
 * In order to undo the VM accounting done by perf_mmap() we need to destroy
 * the buffer here, where we still have a VM context. This means we need
 * to detach all events redirecting to us.
 */
4413 4414
static void perf_mmap_close(struct vm_area_struct *vma)
{
4415
	struct perf_event *event = vma->vm_file->private_data;
4416

4417
	struct ring_buffer *rb = ring_buffer_get(event);
4418 4419 4420
	struct user_struct *mmap_user = rb->mmap_user;
	int mmap_locked = rb->mmap_locked;
	unsigned long size = perf_data_size(rb);
4421

4422 4423 4424
	if (event->pmu->event_unmapped)
		event->pmu->event_unmapped(event);

4425 4426 4427 4428 4429 4430 4431 4432 4433 4434 4435 4436 4437 4438
	/*
	 * rb->aux_mmap_count will always drop before rb->mmap_count and
	 * event->mmap_count, so it is ok to use event->mmap_mutex to
	 * serialize with perf_mmap here.
	 */
	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
		atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
		vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;

		rb_free_aux(rb);
		mutex_unlock(&event->mmap_mutex);
	}

4439 4440 4441
	atomic_dec(&rb->mmap_count);

	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4442
		goto out_put;
4443

4444
	ring_buffer_attach(event, NULL);
4445 4446 4447
	mutex_unlock(&event->mmap_mutex);

	/* If there's still other mmap()s of this buffer, we're done. */
4448 4449
	if (atomic_read(&rb->mmap_count))
		goto out_put;
4450

4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464 4465 4466
	/*
	 * No other mmap()s, detach from all other events that might redirect
	 * into the now unreachable buffer. Somewhat complicated by the
	 * fact that rb::event_lock otherwise nests inside mmap_mutex.
	 */
again:
	rcu_read_lock();
	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
		if (!atomic_long_inc_not_zero(&event->refcount)) {
			/*
			 * This event is en-route to free_event() which will
			 * detach it and remove it from the list.
			 */
			continue;
		}
		rcu_read_unlock();
4467

4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478
		mutex_lock(&event->mmap_mutex);
		/*
		 * Check we didn't race with perf_event_set_output() which can
		 * swizzle the rb from under us while we were waiting to
		 * acquire mmap_mutex.
		 *
		 * If we find a different rb; ignore this event, a next
		 * iteration will no longer find it on the list. We have to
		 * still restart the iteration to make sure we're not now
		 * iterating the wrong list.
		 */
4479 4480 4481
		if (event->rb == rb)
			ring_buffer_attach(event, NULL);

4482
		mutex_unlock(&event->mmap_mutex);
4483
		put_event(event);
4484

4485 4486 4487 4488 4489
		/*
		 * Restart the iteration; either we're on the wrong list or
		 * destroyed its integrity by doing a deletion.
		 */
		goto again;
4490
	}
4491 4492 4493 4494 4495 4496 4497 4498 4499 4500 4501 4502 4503 4504 4505
	rcu_read_unlock();

	/*
	 * It could be there's still a few 0-ref events on the list; they'll
	 * get cleaned up by free_event() -- they'll also still have their
	 * ref on the rb and will free it whenever they are done with it.
	 *
	 * Aside from that, this buffer is 'fully' detached and unmapped,
	 * undo the VM accounting.
	 */

	atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
	vma->vm_mm->pinned_vm -= mmap_locked;
	free_uid(mmap_user);

4506
out_put:
4507
	ring_buffer_put(rb); /* could be last */
4508 4509
}

4510
static const struct vm_operations_struct perf_mmap_vmops = {
4511
	.open		= perf_mmap_open,
4512
	.close		= perf_mmap_close, /* non mergable */
4513 4514
	.fault		= perf_mmap_fault,
	.page_mkwrite	= perf_mmap_fault,
4515 4516 4517 4518
};

static int perf_mmap(struct file *file, struct vm_area_struct *vma)
{
4519
	struct perf_event *event = file->private_data;
4520
	unsigned long user_locked, user_lock_limit;
4521
	struct user_struct *user = current_user();
4522
	unsigned long locked, lock_limit;
4523
	struct ring_buffer *rb = NULL;
4524 4525
	unsigned long vma_size;
	unsigned long nr_pages;
4526
	long user_extra = 0, extra = 0;
4527
	int ret = 0, flags = 0;
4528

4529 4530 4531
	/*
	 * Don't allow mmap() of inherited per-task counters. This would
	 * create a performance issue due to all children writing to the
4532
	 * same rb.
4533 4534 4535 4536
	 */
	if (event->cpu == -1 && event->attr.inherit)
		return -EINVAL;

4537
	if (!(vma->vm_flags & VM_SHARED))
4538
		return -EINVAL;
4539 4540

	vma_size = vma->vm_end - vma->vm_start;
4541 4542 4543 4544 4545 4546 4547 4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597 4598 4599 4600

	if (vma->vm_pgoff == 0) {
		nr_pages = (vma_size / PAGE_SIZE) - 1;
	} else {
		/*
		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
		 * mapped, all subsequent mappings should have the same size
		 * and offset. Must be above the normal perf buffer.
		 */
		u64 aux_offset, aux_size;

		if (!event->rb)
			return -EINVAL;

		nr_pages = vma_size / PAGE_SIZE;

		mutex_lock(&event->mmap_mutex);
		ret = -EINVAL;

		rb = event->rb;
		if (!rb)
			goto aux_unlock;

		aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
		aux_size = ACCESS_ONCE(rb->user_page->aux_size);

		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
			goto aux_unlock;

		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
			goto aux_unlock;

		/* already mapped with a different offset */
		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
			goto aux_unlock;

		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
			goto aux_unlock;

		/* already mapped with a different size */
		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
			goto aux_unlock;

		if (!is_power_of_2(nr_pages))
			goto aux_unlock;

		if (!atomic_inc_not_zero(&rb->mmap_count))
			goto aux_unlock;

		if (rb_has_aux(rb)) {
			atomic_inc(&rb->aux_mmap_count);
			ret = 0;
			goto unlock;
		}

		atomic_set(&rb->aux_mmap_count, 1);
		user_extra = nr_pages;

		goto accounting;
	}
4601

4602
	/*
4603
	 * If we have rb pages ensure they're a power-of-two number, so we
4604 4605
	 * can do bitmasks instead of modulo.
	 */
4606
	if (nr_pages != 0 && !is_power_of_2(nr_pages))
4607 4608
		return -EINVAL;

4609
	if (vma_size != PAGE_SIZE * (1 + nr_pages))
4610 4611
		return -EINVAL;

4612
	WARN_ON_ONCE(event->ctx->parent_ctx);
4613
again:
4614
	mutex_lock(&event->mmap_mutex);
4615
	if (event->rb) {
4616
		if (event->rb->nr_pages != nr_pages) {
4617
			ret = -EINVAL;
4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630
			goto unlock;
		}

		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
			/*
			 * Raced against perf_mmap_close() through
			 * perf_event_set_output(). Try again, hope for better
			 * luck.
			 */
			mutex_unlock(&event->mmap_mutex);
			goto again;
		}

4631 4632 4633
		goto unlock;
	}

4634
	user_extra = nr_pages + 1;
4635 4636

accounting:
4637
	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
I
Ingo Molnar 已提交
4638 4639 4640 4641 4642 4643

	/*
	 * Increase the limit linearly with more CPUs:
	 */
	user_lock_limit *= num_online_cpus();

4644
	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4645

4646 4647
	if (user_locked > user_lock_limit)
		extra = user_locked - user_lock_limit;
4648

4649
	lock_limit = rlimit(RLIMIT_MEMLOCK);
4650
	lock_limit >>= PAGE_SHIFT;
4651
	locked = vma->vm_mm->pinned_vm + extra;
4652

4653 4654
	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
		!capable(CAP_IPC_LOCK)) {
4655 4656 4657
		ret = -EPERM;
		goto unlock;
	}
4658

4659
	WARN_ON(!rb && event->rb);
4660

4661
	if (vma->vm_flags & VM_WRITE)
4662
		flags |= RING_BUFFER_WRITABLE;
4663

4664
	if (!rb) {
4665 4666 4667
		rb = rb_alloc(nr_pages,
			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
			      event->cpu, flags);
P
Peter Zijlstra 已提交
4668

4669 4670 4671 4672
		if (!rb) {
			ret = -ENOMEM;
			goto unlock;
		}
4673

4674 4675 4676
		atomic_set(&rb->mmap_count, 1);
		rb->mmap_user = get_current_user();
		rb->mmap_locked = extra;
P
Peter Zijlstra 已提交
4677

4678
		ring_buffer_attach(event, rb);
4679

4680 4681 4682
		perf_event_init_userpage(event);
		perf_event_update_userpage(event);
	} else {
4683 4684
		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
				   event->attr.aux_watermark, flags);
4685 4686 4687
		if (!ret)
			rb->aux_mmap_locked = extra;
	}
4688

4689
unlock:
4690 4691 4692 4693
	if (!ret) {
		atomic_long_add(user_extra, &user->locked_vm);
		vma->vm_mm->pinned_vm += extra;

4694
		atomic_inc(&event->mmap_count);
4695 4696 4697 4698
	} else if (rb) {
		atomic_dec(&rb->mmap_count);
	}
aux_unlock:
4699
	mutex_unlock(&event->mmap_mutex);
4700

4701 4702 4703 4704
	/*
	 * Since pinned accounting is per vm we cannot allow fork() to copy our
	 * vma.
	 */
P
Peter Zijlstra 已提交
4705
	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4706
	vma->vm_ops = &perf_mmap_vmops;
4707

4708 4709 4710
	if (event->pmu->event_mapped)
		event->pmu->event_mapped(event);

4711
	return ret;
4712 4713
}

P
Peter Zijlstra 已提交
4714 4715
static int perf_fasync(int fd, struct file *filp, int on)
{
A
Al Viro 已提交
4716
	struct inode *inode = file_inode(filp);
4717
	struct perf_event *event = filp->private_data;
P
Peter Zijlstra 已提交
4718 4719 4720
	int retval;

	mutex_lock(&inode->i_mutex);
4721
	retval = fasync_helper(fd, filp, on, &event->fasync);
P
Peter Zijlstra 已提交
4722 4723 4724 4725 4726 4727 4728 4729
	mutex_unlock(&inode->i_mutex);

	if (retval < 0)
		return retval;

	return 0;
}

T
Thomas Gleixner 已提交
4730
static const struct file_operations perf_fops = {
4731
	.llseek			= no_llseek,
T
Thomas Gleixner 已提交
4732 4733 4734
	.release		= perf_release,
	.read			= perf_read,
	.poll			= perf_poll,
4735
	.unlocked_ioctl		= perf_ioctl,
P
Pawel Moll 已提交
4736
	.compat_ioctl		= perf_compat_ioctl,
4737
	.mmap			= perf_mmap,
P
Peter Zijlstra 已提交
4738
	.fasync			= perf_fasync,
T
Thomas Gleixner 已提交
4739 4740
};

4741
/*
4742
 * Perf event wakeup
4743 4744 4745 4746 4747
 *
 * If there's data, ensure we set the poll() state and publish everything
 * to user-space before waking everybody up.
 */

4748
void perf_event_wakeup(struct perf_event *event)
4749
{
4750
	ring_buffer_wakeup(event);
4751

4752 4753 4754
	if (event->pending_kill) {
		kill_fasync(&event->fasync, SIGIO, event->pending_kill);
		event->pending_kill = 0;
4755
	}
4756 4757
}

4758
static void perf_pending_event(struct irq_work *entry)
4759
{
4760 4761
	struct perf_event *event = container_of(entry,
			struct perf_event, pending);
4762 4763 4764 4765 4766 4767 4768
	int rctx;

	rctx = perf_swevent_get_recursion_context();
	/*
	 * If we 'fail' here, that's OK, it means recursion is already disabled
	 * and we won't recurse 'further'.
	 */
4769

4770 4771 4772
	if (event->pending_disable) {
		event->pending_disable = 0;
		__perf_event_disable(event);
4773 4774
	}

4775 4776 4777
	if (event->pending_wakeup) {
		event->pending_wakeup = 0;
		perf_event_wakeup(event);
4778
	}
4779 4780 4781

	if (rctx >= 0)
		perf_swevent_put_recursion_context(rctx);
4782 4783
}

4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804
/*
 * We assume there is only KVM supporting the callbacks.
 * Later on, we might change it to a list if there is
 * another virtualization implementation supporting the callbacks.
 */
struct perf_guest_info_callbacks *perf_guest_cbs;

int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
{
	perf_guest_cbs = cbs;
	return 0;
}
EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);

int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
{
	perf_guest_cbs = NULL;
	return 0;
}
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);

4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819
static void
perf_output_sample_regs(struct perf_output_handle *handle,
			struct pt_regs *regs, u64 mask)
{
	int bit;

	for_each_set_bit(bit, (const unsigned long *) &mask,
			 sizeof(mask) * BITS_PER_BYTE) {
		u64 val;

		val = perf_reg_value(regs, bit);
		perf_output_put(handle, val);
	}
}

4820
static void perf_sample_regs_user(struct perf_regs *regs_user,
4821 4822
				  struct pt_regs *regs,
				  struct pt_regs *regs_user_copy)
4823
{
4824 4825
	if (user_mode(regs)) {
		regs_user->abi = perf_reg_abi(current);
4826
		regs_user->regs = regs;
4827 4828
	} else if (current->mm) {
		perf_get_regs_user(regs_user, regs, regs_user_copy);
4829 4830 4831
	} else {
		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
		regs_user->regs = NULL;
4832 4833 4834
	}
}

4835 4836 4837 4838 4839 4840 4841 4842
static void perf_sample_regs_intr(struct perf_regs *regs_intr,
				  struct pt_regs *regs)
{
	regs_intr->regs = regs;
	regs_intr->abi  = perf_reg_abi(current);
}


4843 4844 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868 4869 4870 4871 4872 4873 4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891 4892 4893 4894 4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937
/*
 * Get remaining task size from user stack pointer.
 *
 * It'd be better to take stack vma map and limit this more
 * precisly, but there's no way to get it safely under interrupt,
 * so using TASK_SIZE as limit.
 */
static u64 perf_ustack_task_size(struct pt_regs *regs)
{
	unsigned long addr = perf_user_stack_pointer(regs);

	if (!addr || addr >= TASK_SIZE)
		return 0;

	return TASK_SIZE - addr;
}

static u16
perf_sample_ustack_size(u16 stack_size, u16 header_size,
			struct pt_regs *regs)
{
	u64 task_size;

	/* No regs, no stack pointer, no dump. */
	if (!regs)
		return 0;

	/*
	 * Check if we fit in with the requested stack size into the:
	 * - TASK_SIZE
	 *   If we don't, we limit the size to the TASK_SIZE.
	 *
	 * - remaining sample size
	 *   If we don't, we customize the stack size to
	 *   fit in to the remaining sample size.
	 */

	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
	stack_size = min(stack_size, (u16) task_size);

	/* Current header size plus static size and dynamic size. */
	header_size += 2 * sizeof(u64);

	/* Do we fit in with the current stack dump size? */
	if ((u16) (header_size + stack_size) < header_size) {
		/*
		 * If we overflow the maximum size for the sample,
		 * we customize the stack dump size to fit in.
		 */
		stack_size = USHRT_MAX - header_size - sizeof(u64);
		stack_size = round_up(stack_size, sizeof(u64));
	}

	return stack_size;
}

static void
perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
			  struct pt_regs *regs)
{
	/* Case of a kernel thread, nothing to dump */
	if (!regs) {
		u64 size = 0;
		perf_output_put(handle, size);
	} else {
		unsigned long sp;
		unsigned int rem;
		u64 dyn_size;

		/*
		 * We dump:
		 * static size
		 *   - the size requested by user or the best one we can fit
		 *     in to the sample max size
		 * data
		 *   - user stack dump data
		 * dynamic size
		 *   - the actual dumped size
		 */

		/* Static size. */
		perf_output_put(handle, dump_size);

		/* Data. */
		sp = perf_user_stack_pointer(regs);
		rem = __output_copy_user(handle, (void *) sp, dump_size);
		dyn_size = dump_size - rem;

		perf_output_skip(handle, rem);

		/* Dynamic size. */
		perf_output_put(handle, dyn_size);
	}
}

4938 4939 4940
static void __perf_event_header__init_id(struct perf_event_header *header,
					 struct perf_sample_data *data,
					 struct perf_event *event)
4941 4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953
{
	u64 sample_type = event->attr.sample_type;

	data->type = sample_type;
	header->size += event->id_header_size;

	if (sample_type & PERF_SAMPLE_TID) {
		/* namespace issues */
		data->tid_entry.pid = perf_event_pid(event, current);
		data->tid_entry.tid = perf_event_tid(event, current);
	}

	if (sample_type & PERF_SAMPLE_TIME)
4954
		data->time = perf_event_clock(event);
4955

4956
	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967
		data->id = primary_event_id(event);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		data->stream_id = event->id;

	if (sample_type & PERF_SAMPLE_CPU) {
		data->cpu_entry.cpu	 = raw_smp_processor_id();
		data->cpu_entry.reserved = 0;
	}
}

4968 4969 4970
void perf_event_header__init_id(struct perf_event_header *header,
				struct perf_sample_data *data,
				struct perf_event *event)
4971 4972 4973 4974 4975 4976 4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987 4988 4989 4990 4991 4992 4993 4994
{
	if (event->attr.sample_id_all)
		__perf_event_header__init_id(header, data, event);
}

static void __perf_event__output_id_sample(struct perf_output_handle *handle,
					   struct perf_sample_data *data)
{
	u64 sample_type = data->type;

	if (sample_type & PERF_SAMPLE_TID)
		perf_output_put(handle, data->tid_entry);

	if (sample_type & PERF_SAMPLE_TIME)
		perf_output_put(handle, data->time);

	if (sample_type & PERF_SAMPLE_ID)
		perf_output_put(handle, data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		perf_output_put(handle, data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		perf_output_put(handle, data->cpu_entry);
4995 4996 4997

	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);
4998 4999
}

5000 5001 5002
void perf_event__output_id_sample(struct perf_event *event,
				  struct perf_output_handle *handle,
				  struct perf_sample_data *sample)
5003 5004 5005 5006 5007
{
	if (event->attr.sample_id_all)
		__perf_event__output_id_sample(handle, sample);
}

5008
static void perf_output_read_one(struct perf_output_handle *handle,
5009 5010
				 struct perf_event *event,
				 u64 enabled, u64 running)
5011
{
5012
	u64 read_format = event->attr.read_format;
5013 5014 5015
	u64 values[4];
	int n = 0;

P
Peter Zijlstra 已提交
5016
	values[n++] = perf_event_count(event);
5017
	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5018
		values[n++] = enabled +
5019
			atomic64_read(&event->child_total_time_enabled);
5020 5021
	}
	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5022
		values[n++] = running +
5023
			atomic64_read(&event->child_total_time_running);
5024 5025
	}
	if (read_format & PERF_FORMAT_ID)
5026
		values[n++] = primary_event_id(event);
5027

5028
	__output_copy(handle, values, n * sizeof(u64));
5029 5030 5031
}

/*
5032
 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5033 5034
 */
static void perf_output_read_group(struct perf_output_handle *handle,
5035 5036
			    struct perf_event *event,
			    u64 enabled, u64 running)
5037
{
5038 5039
	struct perf_event *leader = event->group_leader, *sub;
	u64 read_format = event->attr.read_format;
5040 5041 5042 5043 5044 5045
	u64 values[5];
	int n = 0;

	values[n++] = 1 + leader->nr_siblings;

	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5046
		values[n++] = enabled;
5047 5048

	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5049
		values[n++] = running;
5050

5051
	if (leader != event)
5052 5053
		leader->pmu->read(leader);

P
Peter Zijlstra 已提交
5054
	values[n++] = perf_event_count(leader);
5055
	if (read_format & PERF_FORMAT_ID)
5056
		values[n++] = primary_event_id(leader);
5057

5058
	__output_copy(handle, values, n * sizeof(u64));
5059

5060
	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5061 5062
		n = 0;

5063 5064
		if ((sub != event) &&
		    (sub->state == PERF_EVENT_STATE_ACTIVE))
5065 5066
			sub->pmu->read(sub);

P
Peter Zijlstra 已提交
5067
		values[n++] = perf_event_count(sub);
5068
		if (read_format & PERF_FORMAT_ID)
5069
			values[n++] = primary_event_id(sub);
5070

5071
		__output_copy(handle, values, n * sizeof(u64));
5072 5073 5074
	}
}

5075 5076 5077
#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
				 PERF_FORMAT_TOTAL_TIME_RUNNING)

5078
static void perf_output_read(struct perf_output_handle *handle,
5079
			     struct perf_event *event)
5080
{
5081
	u64 enabled = 0, running = 0, now;
5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 5092
	u64 read_format = event->attr.read_format;

	/*
	 * compute total_time_enabled, total_time_running
	 * based on snapshot values taken when the event
	 * was last scheduled in.
	 *
	 * we cannot simply called update_context_time()
	 * because of locking issue as we are called in
	 * NMI context
	 */
5093
	if (read_format & PERF_FORMAT_TOTAL_TIMES)
5094
		calc_timer_values(event, &now, &enabled, &running);
5095

5096
	if (event->attr.read_format & PERF_FORMAT_GROUP)
5097
		perf_output_read_group(handle, event, enabled, running);
5098
	else
5099
		perf_output_read_one(handle, event, enabled, running);
5100 5101
}

5102 5103 5104
void perf_output_sample(struct perf_output_handle *handle,
			struct perf_event_header *header,
			struct perf_sample_data *data,
5105
			struct perf_event *event)
5106 5107 5108 5109 5110
{
	u64 sample_type = data->type;

	perf_output_put(handle, *header);

5111 5112 5113
	if (sample_type & PERF_SAMPLE_IDENTIFIER)
		perf_output_put(handle, data->id);

5114 5115 5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131 5132 5133 5134 5135 5136 5137 5138
	if (sample_type & PERF_SAMPLE_IP)
		perf_output_put(handle, data->ip);

	if (sample_type & PERF_SAMPLE_TID)
		perf_output_put(handle, data->tid_entry);

	if (sample_type & PERF_SAMPLE_TIME)
		perf_output_put(handle, data->time);

	if (sample_type & PERF_SAMPLE_ADDR)
		perf_output_put(handle, data->addr);

	if (sample_type & PERF_SAMPLE_ID)
		perf_output_put(handle, data->id);

	if (sample_type & PERF_SAMPLE_STREAM_ID)
		perf_output_put(handle, data->stream_id);

	if (sample_type & PERF_SAMPLE_CPU)
		perf_output_put(handle, data->cpu_entry);

	if (sample_type & PERF_SAMPLE_PERIOD)
		perf_output_put(handle, data->period);

	if (sample_type & PERF_SAMPLE_READ)
5139
		perf_output_read(handle, event);
5140 5141 5142 5143 5144 5145 5146 5147 5148 5149

	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
		if (data->callchain) {
			int size = 1;

			if (data->callchain)
				size += data->callchain->nr;

			size *= sizeof(u64);

5150
			__output_copy(handle, data->callchain, size);
5151 5152 5153 5154 5155 5156 5157 5158 5159
		} else {
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}

	if (sample_type & PERF_SAMPLE_RAW) {
		if (data->raw) {
			perf_output_put(handle, data->raw->size);
5160 5161
			__output_copy(handle, data->raw->data,
					   data->raw->size);
5162 5163 5164 5165 5166 5167 5168 5169 5170 5171 5172
		} else {
			struct {
				u32	size;
				u32	data;
			} raw = {
				.size = sizeof(u32),
				.data = 0,
			};
			perf_output_put(handle, raw);
		}
	}
5173

5174 5175 5176 5177 5178 5179 5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190
	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
		if (data->br_stack) {
			size_t size;

			size = data->br_stack->nr
			     * sizeof(struct perf_branch_entry);

			perf_output_put(handle, data->br_stack->nr);
			perf_output_copy(handle, data->br_stack->entries, size);
		} else {
			/*
			 * we always store at least the value of nr
			 */
			u64 nr = 0;
			perf_output_put(handle, nr);
		}
	}
5191 5192 5193 5194 5195 5196 5197 5198 5199 5200 5201 5202 5203 5204 5205 5206 5207

	if (sample_type & PERF_SAMPLE_REGS_USER) {
		u64 abi = data->regs_user.abi;

		/*
		 * If there are no regs to dump, notice it through
		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
		 */
		perf_output_put(handle, abi);

		if (abi) {
			u64 mask = event->attr.sample_regs_user;
			perf_output_sample_regs(handle,
						data->regs_user.regs,
						mask);
		}
	}
5208

5209
	if (sample_type & PERF_SAMPLE_STACK_USER) {
5210 5211 5212
		perf_output_sample_ustack(handle,
					  data->stack_user_size,
					  data->regs_user.regs);
5213
	}
A
Andi Kleen 已提交
5214 5215 5216

	if (sample_type & PERF_SAMPLE_WEIGHT)
		perf_output_put(handle, data->weight);
5217 5218 5219

	if (sample_type & PERF_SAMPLE_DATA_SRC)
		perf_output_put(handle, data->data_src.val);
5220

A
Andi Kleen 已提交
5221 5222 5223
	if (sample_type & PERF_SAMPLE_TRANSACTION)
		perf_output_put(handle, data->txn);

5224 5225 5226 5227 5228 5229 5230 5231 5232 5233 5234 5235 5236 5237 5238 5239 5240
	if (sample_type & PERF_SAMPLE_REGS_INTR) {
		u64 abi = data->regs_intr.abi;
		/*
		 * If there are no regs to dump, notice it through
		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
		 */
		perf_output_put(handle, abi);

		if (abi) {
			u64 mask = event->attr.sample_regs_intr;

			perf_output_sample_regs(handle,
						data->regs_intr.regs,
						mask);
		}
	}

5241 5242 5243 5244 5245 5246 5247 5248 5249 5250 5251 5252 5253
	if (!event->attr.watermark) {
		int wakeup_events = event->attr.wakeup_events;

		if (wakeup_events) {
			struct ring_buffer *rb = handle->rb;
			int events = local_inc_return(&rb->events);

			if (events >= wakeup_events) {
				local_sub(wakeup_events, &rb->events);
				local_inc(&rb->wakeup);
			}
		}
	}
5254 5255 5256 5257
}

void perf_prepare_sample(struct perf_event_header *header,
			 struct perf_sample_data *data,
5258
			 struct perf_event *event,
5259
			 struct pt_regs *regs)
5260
{
5261
	u64 sample_type = event->attr.sample_type;
5262

5263
	header->type = PERF_RECORD_SAMPLE;
5264
	header->size = sizeof(*header) + event->header_size;
5265 5266 5267

	header->misc = 0;
	header->misc |= perf_misc_flags(regs);
5268

5269
	__perf_event_header__init_id(header, data, event);
5270

5271
	if (sample_type & PERF_SAMPLE_IP)
5272 5273
		data->ip = perf_instruction_pointer(regs);

5274
	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5275
		int size = 1;
5276

5277
		data->callchain = perf_callchain(event, regs);
5278 5279 5280 5281 5282

		if (data->callchain)
			size += data->callchain->nr;

		header->size += size * sizeof(u64);
5283 5284
	}

5285
	if (sample_type & PERF_SAMPLE_RAW) {
5286 5287 5288 5289 5290 5291 5292 5293
		int size = sizeof(u32);

		if (data->raw)
			size += data->raw->size;
		else
			size += sizeof(u32);

		WARN_ON_ONCE(size & (sizeof(u64)-1));
5294
		header->size += size;
5295
	}
5296 5297 5298 5299 5300 5301 5302 5303 5304

	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
		int size = sizeof(u64); /* nr */
		if (data->br_stack) {
			size += data->br_stack->nr
			      * sizeof(struct perf_branch_entry);
		}
		header->size += size;
	}
5305

5306
	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5307 5308
		perf_sample_regs_user(&data->regs_user, regs,
				      &data->regs_user_copy);
5309

5310 5311 5312 5313 5314 5315 5316 5317 5318 5319 5320
	if (sample_type & PERF_SAMPLE_REGS_USER) {
		/* regs dump ABI info */
		int size = sizeof(u64);

		if (data->regs_user.regs) {
			u64 mask = event->attr.sample_regs_user;
			size += hweight64(mask) * sizeof(u64);
		}

		header->size += size;
	}
5321 5322 5323 5324 5325 5326 5327 5328 5329 5330 5331 5332

	if (sample_type & PERF_SAMPLE_STACK_USER) {
		/*
		 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
		 * processed as the last one or have additional check added
		 * in case new sample type is added, because we could eat
		 * up the rest of the sample size.
		 */
		u16 stack_size = event->attr.sample_stack_user;
		u16 size = sizeof(u64);

		stack_size = perf_sample_ustack_size(stack_size, header->size,
5333
						     data->regs_user.regs);
5334 5335 5336 5337 5338 5339 5340 5341 5342 5343 5344 5345

		/*
		 * If there is something to dump, add space for the dump
		 * itself and for the field that tells the dynamic size,
		 * which is how many have been actually dumped.
		 */
		if (stack_size)
			size += sizeof(u64) + stack_size;

		data->stack_user_size = stack_size;
		header->size += size;
	}
5346 5347 5348 5349 5350 5351 5352 5353 5354 5355 5356 5357 5358 5359 5360

	if (sample_type & PERF_SAMPLE_REGS_INTR) {
		/* regs dump ABI info */
		int size = sizeof(u64);

		perf_sample_regs_intr(&data->regs_intr, regs);

		if (data->regs_intr.regs) {
			u64 mask = event->attr.sample_regs_intr;

			size += hweight64(mask) * sizeof(u64);
		}

		header->size += size;
	}
5361
}
5362

5363
static void perf_event_output(struct perf_event *event,
5364 5365 5366 5367 5368
				struct perf_sample_data *data,
				struct pt_regs *regs)
{
	struct perf_output_handle handle;
	struct perf_event_header header;
5369

5370 5371 5372
	/* protect the callchain buffers */
	rcu_read_lock();

5373
	perf_prepare_sample(&header, data, event, regs);
P
Peter Zijlstra 已提交
5374

5375
	if (perf_output_begin(&handle, event, header.size))
5376
		goto exit;
5377

5378
	perf_output_sample(&handle, &header, data, event);
5379

5380
	perf_output_end(&handle);
5381 5382 5383

exit:
	rcu_read_unlock();
5384 5385
}

5386
/*
5387
 * read event_id
5388 5389 5390 5391 5392 5393 5394 5395 5396 5397
 */

struct perf_read_event {
	struct perf_event_header	header;

	u32				pid;
	u32				tid;
};

static void
5398
perf_event_read_event(struct perf_event *event,
5399 5400 5401
			struct task_struct *task)
{
	struct perf_output_handle handle;
5402
	struct perf_sample_data sample;
5403
	struct perf_read_event read_event = {
5404
		.header = {
5405
			.type = PERF_RECORD_READ,
5406
			.misc = 0,
5407
			.size = sizeof(read_event) + event->read_size,
5408
		},
5409 5410
		.pid = perf_event_pid(event, task),
		.tid = perf_event_tid(event, task),
5411
	};
5412
	int ret;
5413

5414
	perf_event_header__init_id(&read_event.header, &sample, event);
5415
	ret = perf_output_begin(&handle, event, read_event.header.size);
5416 5417 5418
	if (ret)
		return;

5419
	perf_output_put(&handle, read_event);
5420
	perf_output_read(&handle, event);
5421
	perf_event__output_id_sample(event, &handle, &sample);
5422

5423 5424 5425
	perf_output_end(&handle);
}

5426 5427 5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439
typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);

static void
perf_event_aux_ctx(struct perf_event_context *ctx,
		   perf_event_aux_output_cb output,
		   void *data)
{
	struct perf_event *event;

	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
		if (event->state < PERF_EVENT_STATE_INACTIVE)
			continue;
		if (!event_filter_match(event))
			continue;
5440
		output(event, data);
5441 5442 5443 5444
	}
}

static void
5445
perf_event_aux(perf_event_aux_output_cb output, void *data,
5446 5447 5448 5449 5450 5451 5452 5453 5454 5455 5456 5457
	       struct perf_event_context *task_ctx)
{
	struct perf_cpu_context *cpuctx;
	struct perf_event_context *ctx;
	struct pmu *pmu;
	int ctxn;

	rcu_read_lock();
	list_for_each_entry_rcu(pmu, &pmus, entry) {
		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
		if (cpuctx->unique_pmu != pmu)
			goto next;
5458
		perf_event_aux_ctx(&cpuctx->ctx, output, data);
5459 5460 5461 5462 5463 5464 5465
		if (task_ctx)
			goto next;
		ctxn = pmu->task_ctx_nr;
		if (ctxn < 0)
			goto next;
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
5466
			perf_event_aux_ctx(ctx, output, data);
5467 5468 5469 5470 5471 5472
next:
		put_cpu_ptr(pmu->pmu_cpu_context);
	}

	if (task_ctx) {
		preempt_disable();
5473
		perf_event_aux_ctx(task_ctx, output, data);
5474 5475 5476 5477 5478
		preempt_enable();
	}
	rcu_read_unlock();
}

P
Peter Zijlstra 已提交
5479
/*
P
Peter Zijlstra 已提交
5480 5481
 * task tracking -- fork/exit
 *
5482
 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
P
Peter Zijlstra 已提交
5483 5484
 */

P
Peter Zijlstra 已提交
5485
struct perf_task_event {
5486
	struct task_struct		*task;
5487
	struct perf_event_context	*task_ctx;
P
Peter Zijlstra 已提交
5488 5489 5490 5491 5492 5493

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				ppid;
P
Peter Zijlstra 已提交
5494 5495
		u32				tid;
		u32				ptid;
5496
		u64				time;
5497
	} event_id;
P
Peter Zijlstra 已提交
5498 5499
};

5500 5501
static int perf_event_task_match(struct perf_event *event)
{
5502 5503 5504
	return event->attr.comm  || event->attr.mmap ||
	       event->attr.mmap2 || event->attr.mmap_data ||
	       event->attr.task;
5505 5506
}

5507
static void perf_event_task_output(struct perf_event *event,
5508
				   void *data)
P
Peter Zijlstra 已提交
5509
{
5510
	struct perf_task_event *task_event = data;
P
Peter Zijlstra 已提交
5511
	struct perf_output_handle handle;
5512
	struct perf_sample_data	sample;
P
Peter Zijlstra 已提交
5513
	struct task_struct *task = task_event->task;
5514
	int ret, size = task_event->event_id.header.size;
5515

5516 5517 5518
	if (!perf_event_task_match(event))
		return;

5519
	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
P
Peter Zijlstra 已提交
5520

5521
	ret = perf_output_begin(&handle, event,
5522
				task_event->event_id.header.size);
5523
	if (ret)
5524
		goto out;
P
Peter Zijlstra 已提交
5525

5526 5527
	task_event->event_id.pid = perf_event_pid(event, task);
	task_event->event_id.ppid = perf_event_pid(event, current);
P
Peter Zijlstra 已提交
5528

5529 5530
	task_event->event_id.tid = perf_event_tid(event, task);
	task_event->event_id.ptid = perf_event_tid(event, current);
P
Peter Zijlstra 已提交
5531

5532 5533
	task_event->event_id.time = perf_event_clock(event);

5534
	perf_output_put(&handle, task_event->event_id);
5535

5536 5537
	perf_event__output_id_sample(event, &handle, &sample);

P
Peter Zijlstra 已提交
5538
	perf_output_end(&handle);
5539 5540
out:
	task_event->event_id.header.size = size;
P
Peter Zijlstra 已提交
5541 5542
}

5543 5544
static void perf_event_task(struct task_struct *task,
			      struct perf_event_context *task_ctx,
5545
			      int new)
P
Peter Zijlstra 已提交
5546
{
P
Peter Zijlstra 已提交
5547
	struct perf_task_event task_event;
P
Peter Zijlstra 已提交
5548

5549 5550 5551
	if (!atomic_read(&nr_comm_events) &&
	    !atomic_read(&nr_mmap_events) &&
	    !atomic_read(&nr_task_events))
P
Peter Zijlstra 已提交
5552 5553
		return;

P
Peter Zijlstra 已提交
5554
	task_event = (struct perf_task_event){
5555 5556
		.task	  = task,
		.task_ctx = task_ctx,
5557
		.event_id    = {
P
Peter Zijlstra 已提交
5558
			.header = {
5559
				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5560
				.misc = 0,
5561
				.size = sizeof(task_event.event_id),
P
Peter Zijlstra 已提交
5562
			},
5563 5564
			/* .pid  */
			/* .ppid */
P
Peter Zijlstra 已提交
5565 5566
			/* .tid  */
			/* .ptid */
5567
			/* .time */
P
Peter Zijlstra 已提交
5568 5569 5570
		},
	};

5571
	perf_event_aux(perf_event_task_output,
5572 5573
		       &task_event,
		       task_ctx);
P
Peter Zijlstra 已提交
5574 5575
}

5576
void perf_event_fork(struct task_struct *task)
P
Peter Zijlstra 已提交
5577
{
5578
	perf_event_task(task, NULL, 1);
P
Peter Zijlstra 已提交
5579 5580
}

5581 5582 5583 5584 5585
/*
 * comm tracking
 */

struct perf_comm_event {
5586 5587
	struct task_struct	*task;
	char			*comm;
5588 5589 5590 5591 5592 5593 5594
	int			comm_size;

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
5595
	} event_id;
5596 5597
};

5598 5599 5600 5601 5602
static int perf_event_comm_match(struct perf_event *event)
{
	return event->attr.comm;
}

5603
static void perf_event_comm_output(struct perf_event *event,
5604
				   void *data)
5605
{
5606
	struct perf_comm_event *comm_event = data;
5607
	struct perf_output_handle handle;
5608
	struct perf_sample_data sample;
5609
	int size = comm_event->event_id.header.size;
5610 5611
	int ret;

5612 5613 5614
	if (!perf_event_comm_match(event))
		return;

5615 5616
	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
5617
				comm_event->event_id.header.size);
5618 5619

	if (ret)
5620
		goto out;
5621

5622 5623
	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5624

5625
	perf_output_put(&handle, comm_event->event_id);
5626
	__output_copy(&handle, comm_event->comm,
5627
				   comm_event->comm_size);
5628 5629 5630

	perf_event__output_id_sample(event, &handle, &sample);

5631
	perf_output_end(&handle);
5632 5633
out:
	comm_event->event_id.header.size = size;
5634 5635
}

5636
static void perf_event_comm_event(struct perf_comm_event *comm_event)
5637
{
5638
	char comm[TASK_COMM_LEN];
5639 5640
	unsigned int size;

5641
	memset(comm, 0, sizeof(comm));
5642
	strlcpy(comm, comm_event->task->comm, sizeof(comm));
5643
	size = ALIGN(strlen(comm)+1, sizeof(u64));
5644 5645 5646 5647

	comm_event->comm = comm;
	comm_event->comm_size = size;

5648
	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
P
Peter Zijlstra 已提交
5649

5650
	perf_event_aux(perf_event_comm_output,
5651 5652
		       comm_event,
		       NULL);
5653 5654
}

5655
void perf_event_comm(struct task_struct *task, bool exec)
5656
{
5657 5658
	struct perf_comm_event comm_event;

5659
	if (!atomic_read(&nr_comm_events))
5660
		return;
5661

5662
	comm_event = (struct perf_comm_event){
5663
		.task	= task,
5664 5665
		/* .comm      */
		/* .comm_size */
5666
		.event_id  = {
5667
			.header = {
5668
				.type = PERF_RECORD_COMM,
5669
				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5670 5671 5672 5673
				/* .size */
			},
			/* .pid */
			/* .tid */
5674 5675 5676
		},
	};

5677
	perf_event_comm_event(&comm_event);
5678 5679
}

5680 5681 5682 5683 5684
/*
 * mmap tracking
 */

struct perf_mmap_event {
5685 5686 5687 5688
	struct vm_area_struct	*vma;

	const char		*file_name;
	int			file_size;
5689 5690 5691
	int			maj, min;
	u64			ino;
	u64			ino_generation;
5692
	u32			prot, flags;
5693 5694 5695 5696 5697 5698 5699 5700 5701

	struct {
		struct perf_event_header	header;

		u32				pid;
		u32				tid;
		u64				start;
		u64				len;
		u64				pgoff;
5702
	} event_id;
5703 5704
};

5705 5706 5707 5708 5709 5710 5711 5712
static int perf_event_mmap_match(struct perf_event *event,
				 void *data)
{
	struct perf_mmap_event *mmap_event = data;
	struct vm_area_struct *vma = mmap_event->vma;
	int executable = vma->vm_flags & VM_EXEC;

	return (!executable && event->attr.mmap_data) ||
5713
	       (executable && (event->attr.mmap || event->attr.mmap2));
5714 5715
}

5716
static void perf_event_mmap_output(struct perf_event *event,
5717
				   void *data)
5718
{
5719
	struct perf_mmap_event *mmap_event = data;
5720
	struct perf_output_handle handle;
5721
	struct perf_sample_data sample;
5722
	int size = mmap_event->event_id.header.size;
5723
	int ret;
5724

5725 5726 5727
	if (!perf_event_mmap_match(event, data))
		return;

5728 5729 5730 5731 5732
	if (event->attr.mmap2) {
		mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
		mmap_event->event_id.header.size += sizeof(mmap_event->maj);
		mmap_event->event_id.header.size += sizeof(mmap_event->min);
		mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5733
		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5734 5735
		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5736 5737
	}

5738 5739
	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
	ret = perf_output_begin(&handle, event,
5740
				mmap_event->event_id.header.size);
5741
	if (ret)
5742
		goto out;
5743

5744 5745
	mmap_event->event_id.pid = perf_event_pid(event, current);
	mmap_event->event_id.tid = perf_event_tid(event, current);
5746

5747
	perf_output_put(&handle, mmap_event->event_id);
5748 5749 5750 5751 5752 5753

	if (event->attr.mmap2) {
		perf_output_put(&handle, mmap_event->maj);
		perf_output_put(&handle, mmap_event->min);
		perf_output_put(&handle, mmap_event->ino);
		perf_output_put(&handle, mmap_event->ino_generation);
5754 5755
		perf_output_put(&handle, mmap_event->prot);
		perf_output_put(&handle, mmap_event->flags);
5756 5757
	}

5758
	__output_copy(&handle, mmap_event->file_name,
5759
				   mmap_event->file_size);
5760 5761 5762

	perf_event__output_id_sample(event, &handle, &sample);

5763
	perf_output_end(&handle);
5764 5765
out:
	mmap_event->event_id.header.size = size;
5766 5767
}

5768
static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5769
{
5770 5771
	struct vm_area_struct *vma = mmap_event->vma;
	struct file *file = vma->vm_file;
5772 5773
	int maj = 0, min = 0;
	u64 ino = 0, gen = 0;
5774
	u32 prot = 0, flags = 0;
5775 5776 5777
	unsigned int size;
	char tmp[16];
	char *buf = NULL;
5778
	char *name;
5779

5780
	if (file) {
5781 5782
		struct inode *inode;
		dev_t dev;
5783

5784
		buf = kmalloc(PATH_MAX, GFP_KERNEL);
5785
		if (!buf) {
5786 5787
			name = "//enomem";
			goto cpy_name;
5788
		}
5789
		/*
5790
		 * d_path() works from the end of the rb backwards, so we
5791 5792 5793
		 * need to add enough zero bytes after the string to handle
		 * the 64bit alignment we do later.
		 */
5794
		name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64));
5795
		if (IS_ERR(name)) {
5796 5797
			name = "//toolong";
			goto cpy_name;
5798
		}
5799 5800 5801 5802 5803 5804
		inode = file_inode(vma->vm_file);
		dev = inode->i_sb->s_dev;
		ino = inode->i_ino;
		gen = inode->i_generation;
		maj = MAJOR(dev);
		min = MINOR(dev);
5805 5806 5807 5808 5809 5810 5811 5812 5813 5814 5815 5816 5817 5818 5819 5820 5821 5822 5823 5824 5825 5826

		if (vma->vm_flags & VM_READ)
			prot |= PROT_READ;
		if (vma->vm_flags & VM_WRITE)
			prot |= PROT_WRITE;
		if (vma->vm_flags & VM_EXEC)
			prot |= PROT_EXEC;

		if (vma->vm_flags & VM_MAYSHARE)
			flags = MAP_SHARED;
		else
			flags = MAP_PRIVATE;

		if (vma->vm_flags & VM_DENYWRITE)
			flags |= MAP_DENYWRITE;
		if (vma->vm_flags & VM_MAYEXEC)
			flags |= MAP_EXECUTABLE;
		if (vma->vm_flags & VM_LOCKED)
			flags |= MAP_LOCKED;
		if (vma->vm_flags & VM_HUGETLB)
			flags |= MAP_HUGETLB;

5827
		goto got_name;
5828
	} else {
5829 5830 5831 5832 5833 5834
		if (vma->vm_ops && vma->vm_ops->name) {
			name = (char *) vma->vm_ops->name(vma);
			if (name)
				goto cpy_name;
		}

5835
		name = (char *)arch_vma_name(vma);
5836 5837
		if (name)
			goto cpy_name;
5838

5839
		if (vma->vm_start <= vma->vm_mm->start_brk &&
5840
				vma->vm_end >= vma->vm_mm->brk) {
5841 5842
			name = "[heap]";
			goto cpy_name;
5843 5844
		}
		if (vma->vm_start <= vma->vm_mm->start_stack &&
5845
				vma->vm_end >= vma->vm_mm->start_stack) {
5846 5847
			name = "[stack]";
			goto cpy_name;
5848 5849
		}

5850 5851
		name = "//anon";
		goto cpy_name;
5852 5853
	}

5854 5855 5856
cpy_name:
	strlcpy(tmp, name, sizeof(tmp));
	name = tmp;
5857
got_name:
5858 5859 5860 5861 5862 5863 5864 5865
	/*
	 * Since our buffer works in 8 byte units we need to align our string
	 * size to a multiple of 8. However, we must guarantee the tail end is
	 * zero'd out to avoid leaking random bits to userspace.
	 */
	size = strlen(name)+1;
	while (!IS_ALIGNED(size, sizeof(u64)))
		name[size++] = '\0';
5866 5867 5868

	mmap_event->file_name = name;
	mmap_event->file_size = size;
5869 5870 5871 5872
	mmap_event->maj = maj;
	mmap_event->min = min;
	mmap_event->ino = ino;
	mmap_event->ino_generation = gen;
5873 5874
	mmap_event->prot = prot;
	mmap_event->flags = flags;
5875

5876 5877 5878
	if (!(vma->vm_flags & VM_EXEC))
		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;

5879
	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
5880

5881
	perf_event_aux(perf_event_mmap_output,
5882 5883
		       mmap_event,
		       NULL);
5884

5885 5886 5887
	kfree(buf);
}

5888
void perf_event_mmap(struct vm_area_struct *vma)
5889
{
5890 5891
	struct perf_mmap_event mmap_event;

5892
	if (!atomic_read(&nr_mmap_events))
5893 5894 5895
		return;

	mmap_event = (struct perf_mmap_event){
5896
		.vma	= vma,
5897 5898
		/* .file_name */
		/* .file_size */
5899
		.event_id  = {
5900
			.header = {
5901
				.type = PERF_RECORD_MMAP,
5902
				.misc = PERF_RECORD_MISC_USER,
5903 5904 5905 5906
				/* .size */
			},
			/* .pid */
			/* .tid */
5907 5908
			.start  = vma->vm_start,
			.len    = vma->vm_end - vma->vm_start,
5909
			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
5910
		},
5911 5912 5913 5914
		/* .maj (attr_mmap2 only) */
		/* .min (attr_mmap2 only) */
		/* .ino (attr_mmap2 only) */
		/* .ino_generation (attr_mmap2 only) */
5915 5916
		/* .prot (attr_mmap2 only) */
		/* .flags (attr_mmap2 only) */
5917 5918
	};

5919
	perf_event_mmap_event(&mmap_event);
5920 5921
}

A
Alexander Shishkin 已提交
5922 5923 5924 5925 5926 5927 5928 5929 5930 5931 5932 5933 5934 5935 5936 5937 5938 5939 5940 5941 5942 5943 5944 5945 5946 5947 5948 5949 5950 5951 5952 5953 5954 5955
void perf_event_aux_event(struct perf_event *event, unsigned long head,
			  unsigned long size, u64 flags)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	struct perf_aux_event {
		struct perf_event_header	header;
		u64				offset;
		u64				size;
		u64				flags;
	} rec = {
		.header = {
			.type = PERF_RECORD_AUX,
			.misc = 0,
			.size = sizeof(rec),
		},
		.offset		= head,
		.size		= size,
		.flags		= flags,
	};
	int ret;

	perf_event_header__init_id(&rec.header, &sample, event);
	ret = perf_output_begin(&handle, event, rec.header.size);

	if (ret)
		return;

	perf_output_put(&handle, rec);
	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
}

5956 5957 5958 5959
/*
 * IRQ throttle logging
 */

5960
static void perf_log_throttle(struct perf_event *event, int enable)
5961 5962
{
	struct perf_output_handle handle;
5963
	struct perf_sample_data sample;
5964 5965 5966 5967 5968
	int ret;

	struct {
		struct perf_event_header	header;
		u64				time;
5969
		u64				id;
5970
		u64				stream_id;
5971 5972
	} throttle_event = {
		.header = {
5973
			.type = PERF_RECORD_THROTTLE,
5974 5975 5976
			.misc = 0,
			.size = sizeof(throttle_event),
		},
5977
		.time		= perf_event_clock(event),
5978 5979
		.id		= primary_event_id(event),
		.stream_id	= event->id,
5980 5981
	};

5982
	if (enable)
5983
		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
5984

5985 5986 5987
	perf_event_header__init_id(&throttle_event.header, &sample, event);

	ret = perf_output_begin(&handle, event,
5988
				throttle_event.header.size);
5989 5990 5991 5992
	if (ret)
		return;

	perf_output_put(&handle, throttle_event);
5993
	perf_event__output_id_sample(event, &handle, &sample);
5994 5995 5996
	perf_output_end(&handle);
}

5997 5998 5999 6000 6001 6002 6003 6004 6005 6006 6007 6008 6009 6010 6011 6012 6013 6014 6015 6016 6017 6018 6019 6020 6021 6022 6023 6024 6025 6026 6027 6028 6029 6030 6031 6032 6033 6034
static void perf_log_itrace_start(struct perf_event *event)
{
	struct perf_output_handle handle;
	struct perf_sample_data sample;
	struct perf_aux_event {
		struct perf_event_header        header;
		u32				pid;
		u32				tid;
	} rec;
	int ret;

	if (event->parent)
		event = event->parent;

	if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
	    event->hw.itrace_started)
		return;

	event->hw.itrace_started = 1;

	rec.header.type	= PERF_RECORD_ITRACE_START;
	rec.header.misc	= 0;
	rec.header.size	= sizeof(rec);
	rec.pid	= perf_event_pid(event, current);
	rec.tid	= perf_event_tid(event, current);

	perf_event_header__init_id(&rec.header, &sample, event);
	ret = perf_output_begin(&handle, event, rec.header.size);

	if (ret)
		return;

	perf_output_put(&handle, rec);
	perf_event__output_id_sample(event, &handle, &sample);

	perf_output_end(&handle);
}

6035
/*
6036
 * Generic event overflow handling, sampling.
6037 6038
 */

6039
static int __perf_event_overflow(struct perf_event *event,
6040 6041
				   int throttle, struct perf_sample_data *data,
				   struct pt_regs *regs)
6042
{
6043 6044
	int events = atomic_read(&event->event_limit);
	struct hw_perf_event *hwc = &event->hw;
6045
	u64 seq;
6046 6047
	int ret = 0;

6048 6049 6050 6051 6052 6053 6054
	/*
	 * Non-sampling counters might still use the PMI to fold short
	 * hardware counters, ignore those.
	 */
	if (unlikely(!is_sampling_event(event)))
		return 0;

6055 6056 6057 6058 6059 6060 6061 6062 6063
	seq = __this_cpu_read(perf_throttled_seq);
	if (seq != hwc->interrupts_seq) {
		hwc->interrupts_seq = seq;
		hwc->interrupts = 1;
	} else {
		hwc->interrupts++;
		if (unlikely(throttle
			     && hwc->interrupts >= max_samples_per_tick)) {
			__this_cpu_inc(perf_throttled_count);
P
Peter Zijlstra 已提交
6064 6065
			hwc->interrupts = MAX_INTERRUPTS;
			perf_log_throttle(event, 0);
6066
			tick_nohz_full_kick();
6067 6068
			ret = 1;
		}
6069
	}
6070

6071
	if (event->attr.freq) {
P
Peter Zijlstra 已提交
6072
		u64 now = perf_clock();
6073
		s64 delta = now - hwc->freq_time_stamp;
6074

6075
		hwc->freq_time_stamp = now;
6076

6077
		if (delta > 0 && delta < 2*TICK_NSEC)
6078
			perf_adjust_period(event, delta, hwc->last_period, true);
6079 6080
	}

6081 6082
	/*
	 * XXX event_limit might not quite work as expected on inherited
6083
	 * events
6084 6085
	 */

6086 6087
	event->pending_kill = POLL_IN;
	if (events && atomic_dec_and_test(&event->event_limit)) {
6088
		ret = 1;
6089
		event->pending_kill = POLL_HUP;
6090 6091
		event->pending_disable = 1;
		irq_work_queue(&event->pending);
6092 6093
	}

6094
	if (event->overflow_handler)
6095
		event->overflow_handler(event, data, regs);
6096
	else
6097
		perf_event_output(event, data, regs);
6098

P
Peter Zijlstra 已提交
6099
	if (event->fasync && event->pending_kill) {
6100 6101
		event->pending_wakeup = 1;
		irq_work_queue(&event->pending);
P
Peter Zijlstra 已提交
6102 6103
	}

6104
	return ret;
6105 6106
}

6107
int perf_event_overflow(struct perf_event *event,
6108 6109
			  struct perf_sample_data *data,
			  struct pt_regs *regs)
6110
{
6111
	return __perf_event_overflow(event, 1, data, regs);
6112 6113
}

6114
/*
6115
 * Generic software event infrastructure
6116 6117
 */

6118 6119 6120 6121 6122 6123 6124
struct swevent_htable {
	struct swevent_hlist		*swevent_hlist;
	struct mutex			hlist_mutex;
	int				hlist_refcount;

	/* Recursion avoidance in each contexts */
	int				recursion[PERF_NR_CONTEXTS];
6125 6126 6127

	/* Keeps track of cpu being initialized/exited */
	bool				online;
6128 6129 6130 6131
};

static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);

6132
/*
6133 6134
 * We directly increment event->count and keep a second value in
 * event->hw.period_left to count intervals. This period event
6135 6136 6137 6138
 * is kept in the range [-sample_period, 0] so that we can use the
 * sign as trigger.
 */

6139
u64 perf_swevent_set_period(struct perf_event *event)
6140
{
6141
	struct hw_perf_event *hwc = &event->hw;
6142 6143 6144 6145 6146
	u64 period = hwc->last_period;
	u64 nr, offset;
	s64 old, val;

	hwc->last_period = hwc->sample_period;
6147 6148

again:
6149
	old = val = local64_read(&hwc->period_left);
6150 6151
	if (val < 0)
		return 0;
6152

6153 6154 6155
	nr = div64_u64(period + val, period);
	offset = nr * period;
	val -= offset;
6156
	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6157
		goto again;
6158

6159
	return nr;
6160 6161
}

6162
static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6163
				    struct perf_sample_data *data,
6164
				    struct pt_regs *regs)
6165
{
6166
	struct hw_perf_event *hwc = &event->hw;
6167
	int throttle = 0;
6168

6169 6170
	if (!overflow)
		overflow = perf_swevent_set_period(event);
6171

6172 6173
	if (hwc->interrupts == MAX_INTERRUPTS)
		return;
6174

6175
	for (; overflow; overflow--) {
6176
		if (__perf_event_overflow(event, throttle,
6177
					    data, regs)) {
6178 6179 6180 6181 6182 6183
			/*
			 * We inhibit the overflow from happening when
			 * hwc->interrupts == MAX_INTERRUPTS.
			 */
			break;
		}
6184
		throttle = 1;
6185
	}
6186 6187
}

P
Peter Zijlstra 已提交
6188
static void perf_swevent_event(struct perf_event *event, u64 nr,
6189
			       struct perf_sample_data *data,
6190
			       struct pt_regs *regs)
6191
{
6192
	struct hw_perf_event *hwc = &event->hw;
6193

6194
	local64_add(nr, &event->count);
6195

6196 6197 6198
	if (!regs)
		return;

6199
	if (!is_sampling_event(event))
6200
		return;
6201

6202 6203 6204 6205 6206 6207
	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
		data->period = nr;
		return perf_swevent_overflow(event, 1, data, regs);
	} else
		data->period = event->hw.last_period;

6208
	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6209
		return perf_swevent_overflow(event, 1, data, regs);
6210

6211
	if (local64_add_negative(nr, &hwc->period_left))
6212
		return;
6213

6214
	perf_swevent_overflow(event, 0, data, regs);
6215 6216
}

6217 6218 6219
static int perf_exclude_event(struct perf_event *event,
			      struct pt_regs *regs)
{
P
Peter Zijlstra 已提交
6220
	if (event->hw.state & PERF_HES_STOPPED)
6221
		return 1;
P
Peter Zijlstra 已提交
6222

6223 6224 6225 6226 6227 6228 6229 6230 6231 6232 6233
	if (regs) {
		if (event->attr.exclude_user && user_mode(regs))
			return 1;

		if (event->attr.exclude_kernel && !user_mode(regs))
			return 1;
	}

	return 0;
}

6234
static int perf_swevent_match(struct perf_event *event,
P
Peter Zijlstra 已提交
6235
				enum perf_type_id type,
L
Li Zefan 已提交
6236 6237 6238
				u32 event_id,
				struct perf_sample_data *data,
				struct pt_regs *regs)
6239
{
6240
	if (event->attr.type != type)
6241
		return 0;
6242

6243
	if (event->attr.config != event_id)
6244 6245
		return 0;

6246 6247
	if (perf_exclude_event(event, regs))
		return 0;
6248 6249 6250 6251

	return 1;
}

6252 6253 6254 6255 6256 6257 6258
static inline u64 swevent_hash(u64 type, u32 event_id)
{
	u64 val = event_id | (type << 32);

	return hash_64(val, SWEVENT_HLIST_BITS);
}

6259 6260
static inline struct hlist_head *
__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6261
{
6262 6263 6264 6265
	u64 hash = swevent_hash(type, event_id);

	return &hlist->heads[hash];
}
6266

6267 6268
/* For the read side: events when they trigger */
static inline struct hlist_head *
6269
find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6270 6271
{
	struct swevent_hlist *hlist;
6272

6273
	hlist = rcu_dereference(swhash->swevent_hlist);
6274 6275 6276
	if (!hlist)
		return NULL;

6277 6278 6279 6280 6281
	return __find_swevent_head(hlist, type, event_id);
}

/* For the event head insertion and removal in the hlist */
static inline struct hlist_head *
6282
find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6283 6284 6285 6286 6287 6288 6289 6290 6291 6292
{
	struct swevent_hlist *hlist;
	u32 event_id = event->attr.config;
	u64 type = event->attr.type;

	/*
	 * Event scheduling is always serialized against hlist allocation
	 * and release. Which makes the protected version suitable here.
	 * The context lock guarantees that.
	 */
6293
	hlist = rcu_dereference_protected(swhash->swevent_hlist,
6294 6295 6296 6297 6298
					  lockdep_is_held(&event->ctx->lock));
	if (!hlist)
		return NULL;

	return __find_swevent_head(hlist, type, event_id);
6299 6300 6301
}

static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6302
				    u64 nr,
6303 6304
				    struct perf_sample_data *data,
				    struct pt_regs *regs)
6305
{
6306
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6307
	struct perf_event *event;
6308
	struct hlist_head *head;
6309

6310
	rcu_read_lock();
6311
	head = find_swevent_head_rcu(swhash, type, event_id);
6312 6313 6314
	if (!head)
		goto end;

6315
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
L
Li Zefan 已提交
6316
		if (perf_swevent_match(event, type, event_id, data, regs))
6317
			perf_swevent_event(event, nr, data, regs);
6318
	}
6319 6320
end:
	rcu_read_unlock();
6321 6322
}

6323 6324
DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);

6325
int perf_swevent_get_recursion_context(void)
P
Peter Zijlstra 已提交
6326
{
6327
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
P
Peter Zijlstra 已提交
6328

6329
	return get_recursion_context(swhash->recursion);
P
Peter Zijlstra 已提交
6330
}
I
Ingo Molnar 已提交
6331
EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
P
Peter Zijlstra 已提交
6332

6333
inline void perf_swevent_put_recursion_context(int rctx)
6334
{
6335
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6336

6337
	put_recursion_context(swhash->recursion, rctx);
6338
}
6339

6340
void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6341
{
6342
	struct perf_sample_data data;
6343

6344
	if (WARN_ON_ONCE(!regs))
6345
		return;
6346

6347
	perf_sample_data_init(&data, addr, 0);
6348
	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6349 6350 6351 6352 6353 6354 6355 6356 6357 6358 6359 6360
}

void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
	int rctx;

	preempt_disable_notrace();
	rctx = perf_swevent_get_recursion_context();
	if (unlikely(rctx < 0))
		goto fail;

	___perf_sw_event(event_id, nr, regs, addr);
6361 6362

	perf_swevent_put_recursion_context(rctx);
6363
fail:
6364
	preempt_enable_notrace();
6365 6366
}

6367
static void perf_swevent_read(struct perf_event *event)
6368 6369 6370
{
}

P
Peter Zijlstra 已提交
6371
static int perf_swevent_add(struct perf_event *event, int flags)
6372
{
6373
	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6374
	struct hw_perf_event *hwc = &event->hw;
6375 6376
	struct hlist_head *head;

6377
	if (is_sampling_event(event)) {
6378
		hwc->last_period = hwc->sample_period;
6379
		perf_swevent_set_period(event);
6380
	}
6381

P
Peter Zijlstra 已提交
6382 6383
	hwc->state = !(flags & PERF_EF_START);

6384
	head = find_swevent_head(swhash, event);
6385 6386 6387 6388 6389 6390
	if (!head) {
		/*
		 * We can race with cpu hotplug code. Do not
		 * WARN if the cpu just got unplugged.
		 */
		WARN_ON_ONCE(swhash->online);
6391
		return -EINVAL;
6392
	}
6393 6394

	hlist_add_head_rcu(&event->hlist_entry, head);
6395
	perf_event_update_userpage(event);
6396

6397 6398 6399
	return 0;
}

P
Peter Zijlstra 已提交
6400
static void perf_swevent_del(struct perf_event *event, int flags)
6401
{
6402
	hlist_del_rcu(&event->hlist_entry);
6403 6404
}

P
Peter Zijlstra 已提交
6405
static void perf_swevent_start(struct perf_event *event, int flags)
6406
{
P
Peter Zijlstra 已提交
6407
	event->hw.state = 0;
6408
}
I
Ingo Molnar 已提交
6409

P
Peter Zijlstra 已提交
6410
static void perf_swevent_stop(struct perf_event *event, int flags)
6411
{
P
Peter Zijlstra 已提交
6412
	event->hw.state = PERF_HES_STOPPED;
6413 6414
}

6415 6416
/* Deref the hlist from the update side */
static inline struct swevent_hlist *
6417
swevent_hlist_deref(struct swevent_htable *swhash)
6418
{
6419 6420
	return rcu_dereference_protected(swhash->swevent_hlist,
					 lockdep_is_held(&swhash->hlist_mutex));
6421 6422
}

6423
static void swevent_hlist_release(struct swevent_htable *swhash)
6424
{
6425
	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6426

6427
	if (!hlist)
6428 6429
		return;

6430
	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6431
	kfree_rcu(hlist, rcu_head);
6432 6433 6434 6435
}

static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
{
6436
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6437

6438
	mutex_lock(&swhash->hlist_mutex);
6439

6440 6441
	if (!--swhash->hlist_refcount)
		swevent_hlist_release(swhash);
6442

6443
	mutex_unlock(&swhash->hlist_mutex);
6444 6445 6446 6447 6448 6449 6450 6451 6452 6453 6454 6455
}

static void swevent_hlist_put(struct perf_event *event)
{
	int cpu;

	for_each_possible_cpu(cpu)
		swevent_hlist_put_cpu(event, cpu);
}

static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
{
6456
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6457 6458
	int err = 0;

6459
	mutex_lock(&swhash->hlist_mutex);
6460

6461
	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6462 6463 6464 6465 6466 6467 6468
		struct swevent_hlist *hlist;

		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
		if (!hlist) {
			err = -ENOMEM;
			goto exit;
		}
6469
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
6470
	}
6471
	swhash->hlist_refcount++;
P
Peter Zijlstra 已提交
6472
exit:
6473
	mutex_unlock(&swhash->hlist_mutex);
6474 6475 6476 6477 6478 6479 6480 6481 6482 6483 6484 6485 6486 6487 6488 6489 6490 6491 6492 6493

	return err;
}

static int swevent_hlist_get(struct perf_event *event)
{
	int err;
	int cpu, failed_cpu;

	get_online_cpus();
	for_each_possible_cpu(cpu) {
		err = swevent_hlist_get_cpu(event, cpu);
		if (err) {
			failed_cpu = cpu;
			goto fail;
		}
	}
	put_online_cpus();

	return 0;
P
Peter Zijlstra 已提交
6494
fail:
6495 6496 6497 6498 6499 6500 6501 6502 6503 6504
	for_each_possible_cpu(cpu) {
		if (cpu == failed_cpu)
			break;
		swevent_hlist_put_cpu(event, cpu);
	}

	put_online_cpus();
	return err;
}

6505
struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6506

6507 6508 6509
static void sw_perf_event_destroy(struct perf_event *event)
{
	u64 event_id = event->attr.config;
6510

6511 6512
	WARN_ON(event->parent);

6513
	static_key_slow_dec(&perf_swevent_enabled[event_id]);
6514 6515 6516 6517 6518
	swevent_hlist_put(event);
}

static int perf_swevent_init(struct perf_event *event)
{
6519
	u64 event_id = event->attr.config;
6520 6521 6522 6523

	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

6524 6525 6526 6527 6528 6529
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

6530 6531 6532 6533 6534 6535 6536 6537 6538
	switch (event_id) {
	case PERF_COUNT_SW_CPU_CLOCK:
	case PERF_COUNT_SW_TASK_CLOCK:
		return -ENOENT;

	default:
		break;
	}

6539
	if (event_id >= PERF_COUNT_SW_MAX)
6540 6541 6542 6543 6544 6545 6546 6547 6548
		return -ENOENT;

	if (!event->parent) {
		int err;

		err = swevent_hlist_get(event);
		if (err)
			return err;

6549
		static_key_slow_inc(&perf_swevent_enabled[event_id]);
6550 6551 6552 6553 6554 6555 6556
		event->destroy = sw_perf_event_destroy;
	}

	return 0;
}

static struct pmu perf_swevent = {
6557
	.task_ctx_nr	= perf_sw_context,
6558

6559 6560
	.capabilities	= PERF_PMU_CAP_NO_NMI,

6561
	.event_init	= perf_swevent_init,
P
Peter Zijlstra 已提交
6562 6563 6564 6565
	.add		= perf_swevent_add,
	.del		= perf_swevent_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
6566 6567 6568
	.read		= perf_swevent_read,
};

6569 6570
#ifdef CONFIG_EVENT_TRACING

6571 6572 6573 6574 6575 6576 6577 6578 6579 6580 6581 6582 6583 6584
static int perf_tp_filter_match(struct perf_event *event,
				struct perf_sample_data *data)
{
	void *record = data->raw->data;

	if (likely(!event->filter) || filter_match_preds(event->filter, record))
		return 1;
	return 0;
}

static int perf_tp_event_match(struct perf_event *event,
				struct perf_sample_data *data,
				struct pt_regs *regs)
{
6585 6586
	if (event->hw.state & PERF_HES_STOPPED)
		return 0;
6587 6588 6589 6590
	/*
	 * All tracepoints are from kernel-space.
	 */
	if (event->attr.exclude_kernel)
6591 6592 6593 6594 6595 6596 6597 6598 6599
		return 0;

	if (!perf_tp_filter_match(event, data))
		return 0;

	return 1;
}

void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6600 6601
		   struct pt_regs *regs, struct hlist_head *head, int rctx,
		   struct task_struct *task)
6602 6603
{
	struct perf_sample_data data;
6604 6605
	struct perf_event *event;

6606 6607 6608 6609 6610
	struct perf_raw_record raw = {
		.size = entry_size,
		.data = record,
	};

6611
	perf_sample_data_init(&data, addr, 0);
6612 6613
	data.raw = &raw;

6614
	hlist_for_each_entry_rcu(event, head, hlist_entry) {
6615
		if (perf_tp_event_match(event, &data, regs))
6616
			perf_swevent_event(event, count, &data, regs);
6617
	}
6618

6619 6620 6621 6622 6623 6624 6625 6626 6627 6628 6629 6630 6631 6632 6633 6634 6635 6636 6637 6638 6639 6640 6641 6642 6643
	/*
	 * If we got specified a target task, also iterate its context and
	 * deliver this event there too.
	 */
	if (task && task != current) {
		struct perf_event_context *ctx;
		struct trace_entry *entry = record;

		rcu_read_lock();
		ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
		if (!ctx)
			goto unlock;

		list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
			if (event->attr.type != PERF_TYPE_TRACEPOINT)
				continue;
			if (event->attr.config != entry->type)
				continue;
			if (perf_tp_event_match(event, &data, regs))
				perf_swevent_event(event, count, &data, regs);
		}
unlock:
		rcu_read_unlock();
	}

6644
	perf_swevent_put_recursion_context(rctx);
6645 6646 6647
}
EXPORT_SYMBOL_GPL(perf_tp_event);

6648
static void tp_perf_event_destroy(struct perf_event *event)
6649
{
6650
	perf_trace_destroy(event);
6651 6652
}

6653
static int perf_tp_event_init(struct perf_event *event)
6654
{
6655 6656
	int err;

6657 6658 6659
	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -ENOENT;

6660 6661 6662 6663 6664 6665
	/*
	 * no branch sampling for tracepoint events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

6666 6667
	err = perf_trace_init(event);
	if (err)
6668
		return err;
6669

6670
	event->destroy = tp_perf_event_destroy;
6671

6672 6673 6674 6675
	return 0;
}

static struct pmu perf_tracepoint = {
6676 6677
	.task_ctx_nr	= perf_sw_context,

6678
	.event_init	= perf_tp_event_init,
P
Peter Zijlstra 已提交
6679 6680 6681 6682
	.add		= perf_trace_add,
	.del		= perf_trace_del,
	.start		= perf_swevent_start,
	.stop		= perf_swevent_stop,
6683 6684 6685 6686 6687
	.read		= perf_swevent_read,
};

static inline void perf_tp_register(void)
{
P
Peter Zijlstra 已提交
6688
	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6689
}
L
Li Zefan 已提交
6690 6691 6692 6693 6694 6695 6696 6697 6698 6699 6700 6701 6702 6703 6704 6705 6706 6707 6708 6709 6710 6711 6712 6713

static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
	char *filter_str;
	int ret;

	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -EINVAL;

	filter_str = strndup_user(arg, PAGE_SIZE);
	if (IS_ERR(filter_str))
		return PTR_ERR(filter_str);

	ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);

	kfree(filter_str);
	return ret;
}

static void perf_event_free_filter(struct perf_event *event)
{
	ftrace_profile_free_filter(event);
}

6714 6715 6716 6717 6718 6719 6720 6721 6722 6723 6724 6725 6726 6727 6728 6729 6730 6731 6732 6733 6734 6735 6736 6737 6738 6739 6740 6741 6742 6743 6744 6745 6746 6747 6748 6749 6750 6751 6752 6753 6754 6755 6756
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
{
	struct bpf_prog *prog;

	if (event->attr.type != PERF_TYPE_TRACEPOINT)
		return -EINVAL;

	if (event->tp_event->prog)
		return -EEXIST;

	if (!(event->tp_event->flags & TRACE_EVENT_FL_KPROBE))
		/* bpf programs can only be attached to kprobes */
		return -EINVAL;

	prog = bpf_prog_get(prog_fd);
	if (IS_ERR(prog))
		return PTR_ERR(prog);

	if (prog->aux->prog_type != BPF_PROG_TYPE_KPROBE) {
		/* valid fd, but invalid bpf program type */
		bpf_prog_put(prog);
		return -EINVAL;
	}

	event->tp_event->prog = prog;

	return 0;
}

static void perf_event_free_bpf_prog(struct perf_event *event)
{
	struct bpf_prog *prog;

	if (!event->tp_event)
		return;

	prog = event->tp_event->prog;
	if (prog) {
		event->tp_event->prog = NULL;
		bpf_prog_put(prog);
	}
}

6757
#else
L
Li Zefan 已提交
6758

6759
static inline void perf_tp_register(void)
6760 6761
{
}
L
Li Zefan 已提交
6762 6763 6764 6765 6766 6767 6768 6769 6770 6771

static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
	return -ENOENT;
}

static void perf_event_free_filter(struct perf_event *event)
{
}

6772 6773 6774 6775 6776 6777 6778 6779
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
{
	return -ENOENT;
}

static void perf_event_free_bpf_prog(struct perf_event *event)
{
}
6780
#endif /* CONFIG_EVENT_TRACING */
6781

6782
#ifdef CONFIG_HAVE_HW_BREAKPOINT
6783
void perf_bp_event(struct perf_event *bp, void *data)
6784
{
6785 6786 6787
	struct perf_sample_data sample;
	struct pt_regs *regs = data;

6788
	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
6789

P
Peter Zijlstra 已提交
6790
	if (!bp->hw.state && !perf_exclude_event(bp, regs))
6791
		perf_swevent_event(bp, 1, &sample, regs);
6792 6793 6794
}
#endif

6795 6796 6797
/*
 * hrtimer based swevent callback
 */
6798

6799
static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
6800
{
6801 6802 6803 6804 6805
	enum hrtimer_restart ret = HRTIMER_RESTART;
	struct perf_sample_data data;
	struct pt_regs *regs;
	struct perf_event *event;
	u64 period;
6806

6807
	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
P
Peter Zijlstra 已提交
6808 6809 6810 6811

	if (event->state != PERF_EVENT_STATE_ACTIVE)
		return HRTIMER_NORESTART;

6812
	event->pmu->read(event);
6813

6814
	perf_sample_data_init(&data, 0, event->hw.last_period);
6815 6816 6817
	regs = get_irq_regs();

	if (regs && !perf_exclude_event(event, regs)) {
6818
		if (!(event->attr.exclude_idle && is_idle_task(current)))
6819
			if (__perf_event_overflow(event, 1, &data, regs))
6820 6821
				ret = HRTIMER_NORESTART;
	}
6822

6823 6824
	period = max_t(u64, 10000, event->hw.sample_period);
	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
6825

6826
	return ret;
6827 6828
}

6829
static void perf_swevent_start_hrtimer(struct perf_event *event)
6830
{
6831
	struct hw_perf_event *hwc = &event->hw;
6832 6833 6834 6835
	s64 period;

	if (!is_sampling_event(event))
		return;
6836

6837 6838 6839 6840
	period = local64_read(&hwc->period_left);
	if (period) {
		if (period < 0)
			period = 10000;
P
Peter Zijlstra 已提交
6841

6842 6843 6844 6845 6846
		local64_set(&hwc->period_left, 0);
	} else {
		period = max_t(u64, 10000, hwc->sample_period);
	}
	__hrtimer_start_range_ns(&hwc->hrtimer,
6847
				ns_to_ktime(period), 0,
6848
				HRTIMER_MODE_REL_PINNED, 0);
6849
}
6850 6851

static void perf_swevent_cancel_hrtimer(struct perf_event *event)
6852
{
6853 6854
	struct hw_perf_event *hwc = &event->hw;

6855
	if (is_sampling_event(event)) {
6856
		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
P
Peter Zijlstra 已提交
6857
		local64_set(&hwc->period_left, ktime_to_ns(remaining));
6858 6859 6860

		hrtimer_cancel(&hwc->hrtimer);
	}
6861 6862
}

P
Peter Zijlstra 已提交
6863 6864 6865 6866 6867 6868 6869 6870 6871 6872 6873 6874 6875 6876 6877 6878 6879 6880 6881 6882
static void perf_swevent_init_hrtimer(struct perf_event *event)
{
	struct hw_perf_event *hwc = &event->hw;

	if (!is_sampling_event(event))
		return;

	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	hwc->hrtimer.function = perf_swevent_hrtimer;

	/*
	 * Since hrtimers have a fixed rate, we can do a static freq->period
	 * mapping and avoid the whole period adjust feedback stuff.
	 */
	if (event->attr.freq) {
		long freq = event->attr.sample_freq;

		event->attr.sample_period = NSEC_PER_SEC / freq;
		hwc->sample_period = event->attr.sample_period;
		local64_set(&hwc->period_left, hwc->sample_period);
6883
		hwc->last_period = hwc->sample_period;
P
Peter Zijlstra 已提交
6884 6885 6886 6887
		event->attr.freq = 0;
	}
}

6888 6889 6890 6891 6892
/*
 * Software event: cpu wall time clock
 */

static void cpu_clock_event_update(struct perf_event *event)
6893
{
6894 6895 6896
	s64 prev;
	u64 now;

P
Peter Zijlstra 已提交
6897
	now = local_clock();
6898 6899
	prev = local64_xchg(&event->hw.prev_count, now);
	local64_add(now - prev, &event->count);
6900 6901
}

P
Peter Zijlstra 已提交
6902
static void cpu_clock_event_start(struct perf_event *event, int flags)
6903
{
P
Peter Zijlstra 已提交
6904
	local64_set(&event->hw.prev_count, local_clock());
6905 6906 6907
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
6908
static void cpu_clock_event_stop(struct perf_event *event, int flags)
6909
{
6910 6911 6912
	perf_swevent_cancel_hrtimer(event);
	cpu_clock_event_update(event);
}
6913

P
Peter Zijlstra 已提交
6914 6915 6916 6917
static int cpu_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		cpu_clock_event_start(event, flags);
6918
	perf_event_update_userpage(event);
P
Peter Zijlstra 已提交
6919 6920 6921 6922 6923 6924 6925 6926 6927

	return 0;
}

static void cpu_clock_event_del(struct perf_event *event, int flags)
{
	cpu_clock_event_stop(event, flags);
}

6928 6929 6930 6931
static void cpu_clock_event_read(struct perf_event *event)
{
	cpu_clock_event_update(event);
}
6932

6933 6934 6935 6936 6937 6938 6939 6940
static int cpu_clock_event_init(struct perf_event *event)
{
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
		return -ENOENT;

6941 6942 6943 6944 6945 6946
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
6947 6948
	perf_swevent_init_hrtimer(event);

6949
	return 0;
6950 6951
}

6952
static struct pmu perf_cpu_clock = {
6953 6954
	.task_ctx_nr	= perf_sw_context,

6955 6956
	.capabilities	= PERF_PMU_CAP_NO_NMI,

6957
	.event_init	= cpu_clock_event_init,
P
Peter Zijlstra 已提交
6958 6959 6960 6961
	.add		= cpu_clock_event_add,
	.del		= cpu_clock_event_del,
	.start		= cpu_clock_event_start,
	.stop		= cpu_clock_event_stop,
6962 6963 6964 6965 6966 6967 6968 6969
	.read		= cpu_clock_event_read,
};

/*
 * Software event: task time clock
 */

static void task_clock_event_update(struct perf_event *event, u64 now)
6970
{
6971 6972
	u64 prev;
	s64 delta;
6973

6974 6975 6976 6977
	prev = local64_xchg(&event->hw.prev_count, now);
	delta = now - prev;
	local64_add(delta, &event->count);
}
6978

P
Peter Zijlstra 已提交
6979
static void task_clock_event_start(struct perf_event *event, int flags)
6980
{
P
Peter Zijlstra 已提交
6981
	local64_set(&event->hw.prev_count, event->ctx->time);
6982 6983 6984
	perf_swevent_start_hrtimer(event);
}

P
Peter Zijlstra 已提交
6985
static void task_clock_event_stop(struct perf_event *event, int flags)
6986 6987 6988
{
	perf_swevent_cancel_hrtimer(event);
	task_clock_event_update(event, event->ctx->time);
P
Peter Zijlstra 已提交
6989 6990 6991 6992 6993 6994
}

static int task_clock_event_add(struct perf_event *event, int flags)
{
	if (flags & PERF_EF_START)
		task_clock_event_start(event, flags);
6995
	perf_event_update_userpage(event);
6996

P
Peter Zijlstra 已提交
6997 6998 6999 7000 7001 7002
	return 0;
}

static void task_clock_event_del(struct perf_event *event, int flags)
{
	task_clock_event_stop(event, PERF_EF_UPDATE);
7003 7004 7005 7006
}

static void task_clock_event_read(struct perf_event *event)
{
7007 7008 7009
	u64 now = perf_clock();
	u64 delta = now - event->ctx->timestamp;
	u64 time = event->ctx->time + delta;
7010 7011 7012 7013 7014

	task_clock_event_update(event, time);
}

static int task_clock_event_init(struct perf_event *event)
L
Li Zefan 已提交
7015
{
7016 7017 7018 7019 7020 7021
	if (event->attr.type != PERF_TYPE_SOFTWARE)
		return -ENOENT;

	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
		return -ENOENT;

7022 7023 7024 7025 7026 7027
	/*
	 * no branch sampling for software events
	 */
	if (has_branch_stack(event))
		return -EOPNOTSUPP;

P
Peter Zijlstra 已提交
7028 7029
	perf_swevent_init_hrtimer(event);

7030
	return 0;
L
Li Zefan 已提交
7031 7032
}

7033
static struct pmu perf_task_clock = {
7034 7035
	.task_ctx_nr	= perf_sw_context,

7036 7037
	.capabilities	= PERF_PMU_CAP_NO_NMI,

7038
	.event_init	= task_clock_event_init,
P
Peter Zijlstra 已提交
7039 7040 7041 7042
	.add		= task_clock_event_add,
	.del		= task_clock_event_del,
	.start		= task_clock_event_start,
	.stop		= task_clock_event_stop,
7043 7044
	.read		= task_clock_event_read,
};
L
Li Zefan 已提交
7045

P
Peter Zijlstra 已提交
7046
static void perf_pmu_nop_void(struct pmu *pmu)
7047 7048
{
}
L
Li Zefan 已提交
7049

P
Peter Zijlstra 已提交
7050
static int perf_pmu_nop_int(struct pmu *pmu)
L
Li Zefan 已提交
7051
{
P
Peter Zijlstra 已提交
7052
	return 0;
L
Li Zefan 已提交
7053 7054
}

P
Peter Zijlstra 已提交
7055
static void perf_pmu_start_txn(struct pmu *pmu)
L
Li Zefan 已提交
7056
{
P
Peter Zijlstra 已提交
7057
	perf_pmu_disable(pmu);
L
Li Zefan 已提交
7058 7059
}

P
Peter Zijlstra 已提交
7060 7061 7062 7063 7064
static int perf_pmu_commit_txn(struct pmu *pmu)
{
	perf_pmu_enable(pmu);
	return 0;
}
7065

P
Peter Zijlstra 已提交
7066
static void perf_pmu_cancel_txn(struct pmu *pmu)
7067
{
P
Peter Zijlstra 已提交
7068
	perf_pmu_enable(pmu);
7069 7070
}

7071 7072
static int perf_event_idx_default(struct perf_event *event)
{
7073
	return 0;
7074 7075
}

P
Peter Zijlstra 已提交
7076 7077 7078 7079
/*
 * Ensures all contexts with the same task_ctx_nr have the same
 * pmu_cpu_context too.
 */
7080
static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7081
{
P
Peter Zijlstra 已提交
7082
	struct pmu *pmu;
7083

P
Peter Zijlstra 已提交
7084 7085
	if (ctxn < 0)
		return NULL;
7086

P
Peter Zijlstra 已提交
7087 7088 7089 7090
	list_for_each_entry(pmu, &pmus, entry) {
		if (pmu->task_ctx_nr == ctxn)
			return pmu->pmu_cpu_context;
	}
7091

P
Peter Zijlstra 已提交
7092
	return NULL;
7093 7094
}

7095
static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7096
{
7097 7098 7099 7100 7101 7102 7103
	int cpu;

	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);

7104 7105
		if (cpuctx->unique_pmu == old_pmu)
			cpuctx->unique_pmu = pmu;
7106 7107 7108 7109 7110 7111
	}
}

static void free_pmu_context(struct pmu *pmu)
{
	struct pmu *i;
7112

P
Peter Zijlstra 已提交
7113
	mutex_lock(&pmus_lock);
7114
	/*
P
Peter Zijlstra 已提交
7115
	 * Like a real lame refcount.
7116
	 */
7117 7118 7119
	list_for_each_entry(i, &pmus, entry) {
		if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
			update_pmu_context(i, pmu);
P
Peter Zijlstra 已提交
7120
			goto out;
7121
		}
P
Peter Zijlstra 已提交
7122
	}
7123

7124
	free_percpu(pmu->pmu_cpu_context);
P
Peter Zijlstra 已提交
7125 7126
out:
	mutex_unlock(&pmus_lock);
7127
}
P
Peter Zijlstra 已提交
7128
static struct idr pmu_idr;
7129

P
Peter Zijlstra 已提交
7130 7131 7132 7133 7134 7135 7136
static ssize_t
type_show(struct device *dev, struct device_attribute *attr, char *page)
{
	struct pmu *pmu = dev_get_drvdata(dev);

	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
}
7137
static DEVICE_ATTR_RO(type);
P
Peter Zijlstra 已提交
7138

7139 7140 7141 7142 7143 7144 7145 7146 7147 7148 7149 7150 7151 7152 7153 7154 7155 7156 7157 7158 7159 7160 7161 7162 7163 7164 7165 7166 7167 7168 7169 7170 7171 7172 7173 7174 7175 7176 7177 7178 7179 7180 7181
static ssize_t
perf_event_mux_interval_ms_show(struct device *dev,
				struct device_attribute *attr,
				char *page)
{
	struct pmu *pmu = dev_get_drvdata(dev);

	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
}

static ssize_t
perf_event_mux_interval_ms_store(struct device *dev,
				 struct device_attribute *attr,
				 const char *buf, size_t count)
{
	struct pmu *pmu = dev_get_drvdata(dev);
	int timer, cpu, ret;

	ret = kstrtoint(buf, 0, &timer);
	if (ret)
		return ret;

	if (timer < 1)
		return -EINVAL;

	/* same value, noting to do */
	if (timer == pmu->hrtimer_interval_ms)
		return count;

	pmu->hrtimer_interval_ms = timer;

	/* update all cpuctx for this PMU */
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;
		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);

		if (hrtimer_active(&cpuctx->hrtimer))
			hrtimer_forward_now(&cpuctx->hrtimer, cpuctx->hrtimer_interval);
	}

	return count;
}
7182
static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7183

7184 7185 7186 7187
static struct attribute *pmu_dev_attrs[] = {
	&dev_attr_type.attr,
	&dev_attr_perf_event_mux_interval_ms.attr,
	NULL,
P
Peter Zijlstra 已提交
7188
};
7189
ATTRIBUTE_GROUPS(pmu_dev);
P
Peter Zijlstra 已提交
7190 7191 7192 7193

static int pmu_bus_running;
static struct bus_type pmu_bus = {
	.name		= "event_source",
7194
	.dev_groups	= pmu_dev_groups,
P
Peter Zijlstra 已提交
7195 7196 7197 7198 7199 7200 7201 7202 7203 7204 7205 7206 7207 7208 7209
};

static void pmu_dev_release(struct device *dev)
{
	kfree(dev);
}

static int pmu_dev_alloc(struct pmu *pmu)
{
	int ret = -ENOMEM;

	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
	if (!pmu->dev)
		goto out;

7210
	pmu->dev->groups = pmu->attr_groups;
P
Peter Zijlstra 已提交
7211 7212 7213 7214 7215 7216 7217 7218 7219 7220 7221 7222 7223 7224 7225 7226 7227 7228 7229 7230
	device_initialize(pmu->dev);
	ret = dev_set_name(pmu->dev, "%s", pmu->name);
	if (ret)
		goto free_dev;

	dev_set_drvdata(pmu->dev, pmu);
	pmu->dev->bus = &pmu_bus;
	pmu->dev->release = pmu_dev_release;
	ret = device_add(pmu->dev);
	if (ret)
		goto free_dev;

out:
	return ret;

free_dev:
	put_device(pmu->dev);
	goto out;
}

7231
static struct lock_class_key cpuctx_mutex;
7232
static struct lock_class_key cpuctx_lock;
7233

7234
int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7235
{
P
Peter Zijlstra 已提交
7236
	int cpu, ret;
7237

7238
	mutex_lock(&pmus_lock);
P
Peter Zijlstra 已提交
7239 7240 7241 7242
	ret = -ENOMEM;
	pmu->pmu_disable_count = alloc_percpu(int);
	if (!pmu->pmu_disable_count)
		goto unlock;
7243

P
Peter Zijlstra 已提交
7244 7245 7246 7247 7248 7249
	pmu->type = -1;
	if (!name)
		goto skip_type;
	pmu->name = name;

	if (type < 0) {
T
Tejun Heo 已提交
7250 7251 7252
		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
		if (type < 0) {
			ret = type;
P
Peter Zijlstra 已提交
7253 7254 7255 7256 7257
			goto free_pdc;
		}
	}
	pmu->type = type;

P
Peter Zijlstra 已提交
7258 7259 7260 7261 7262 7263
	if (pmu_bus_running) {
		ret = pmu_dev_alloc(pmu);
		if (ret)
			goto free_idr;
	}

P
Peter Zijlstra 已提交
7264
skip_type:
P
Peter Zijlstra 已提交
7265 7266 7267
	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
	if (pmu->pmu_cpu_context)
		goto got_cpu_context;
7268

W
Wei Yongjun 已提交
7269
	ret = -ENOMEM;
P
Peter Zijlstra 已提交
7270 7271
	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
	if (!pmu->pmu_cpu_context)
P
Peter Zijlstra 已提交
7272
		goto free_dev;
7273

P
Peter Zijlstra 已提交
7274 7275 7276 7277
	for_each_possible_cpu(cpu) {
		struct perf_cpu_context *cpuctx;

		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7278
		__perf_event_init_context(&cpuctx->ctx);
7279
		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7280
		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
P
Peter Zijlstra 已提交
7281
		cpuctx->ctx.pmu = pmu;
7282 7283 7284

		__perf_cpu_hrtimer_init(cpuctx, cpu);

7285
		cpuctx->unique_pmu = pmu;
P
Peter Zijlstra 已提交
7286
	}
7287

P
Peter Zijlstra 已提交
7288
got_cpu_context:
P
Peter Zijlstra 已提交
7289 7290 7291 7292 7293 7294 7295 7296 7297 7298 7299 7300 7301 7302
	if (!pmu->start_txn) {
		if (pmu->pmu_enable) {
			/*
			 * If we have pmu_enable/pmu_disable calls, install
			 * transaction stubs that use that to try and batch
			 * hardware accesses.
			 */
			pmu->start_txn  = perf_pmu_start_txn;
			pmu->commit_txn = perf_pmu_commit_txn;
			pmu->cancel_txn = perf_pmu_cancel_txn;
		} else {
			pmu->start_txn  = perf_pmu_nop_void;
			pmu->commit_txn = perf_pmu_nop_int;
			pmu->cancel_txn = perf_pmu_nop_void;
7303
		}
7304
	}
7305

P
Peter Zijlstra 已提交
7306 7307 7308 7309 7310
	if (!pmu->pmu_enable) {
		pmu->pmu_enable  = perf_pmu_nop_void;
		pmu->pmu_disable = perf_pmu_nop_void;
	}

7311 7312 7313
	if (!pmu->event_idx)
		pmu->event_idx = perf_event_idx_default;

7314
	list_add_rcu(&pmu->entry, &pmus);
7315
	atomic_set(&pmu->exclusive_cnt, 0);
P
Peter Zijlstra 已提交
7316 7317
	ret = 0;
unlock:
7318 7319
	mutex_unlock(&pmus_lock);

P
Peter Zijlstra 已提交
7320
	return ret;
P
Peter Zijlstra 已提交
7321

P
Peter Zijlstra 已提交
7322 7323 7324 7325
free_dev:
	device_del(pmu->dev);
	put_device(pmu->dev);

P
Peter Zijlstra 已提交
7326 7327 7328 7329
free_idr:
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);

P
Peter Zijlstra 已提交
7330 7331 7332
free_pdc:
	free_percpu(pmu->pmu_disable_count);
	goto unlock;
7333
}
7334
EXPORT_SYMBOL_GPL(perf_pmu_register);
7335

7336
void perf_pmu_unregister(struct pmu *pmu)
7337
{
7338 7339 7340
	mutex_lock(&pmus_lock);
	list_del_rcu(&pmu->entry);
	mutex_unlock(&pmus_lock);
7341

7342
	/*
P
Peter Zijlstra 已提交
7343 7344
	 * We dereference the pmu list under both SRCU and regular RCU, so
	 * synchronize against both of those.
7345
	 */
7346
	synchronize_srcu(&pmus_srcu);
P
Peter Zijlstra 已提交
7347
	synchronize_rcu();
7348

P
Peter Zijlstra 已提交
7349
	free_percpu(pmu->pmu_disable_count);
P
Peter Zijlstra 已提交
7350 7351
	if (pmu->type >= PERF_TYPE_MAX)
		idr_remove(&pmu_idr, pmu->type);
P
Peter Zijlstra 已提交
7352 7353
	device_del(pmu->dev);
	put_device(pmu->dev);
7354
	free_pmu_context(pmu);
7355
}
7356
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7357

7358 7359
static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
{
P
Peter Zijlstra 已提交
7360
	struct perf_event_context *ctx = NULL;
7361 7362 7363 7364
	int ret;

	if (!try_module_get(pmu->module))
		return -ENODEV;
P
Peter Zijlstra 已提交
7365 7366 7367 7368 7369 7370

	if (event->group_leader != event) {
		ctx = perf_event_ctx_lock(event->group_leader);
		BUG_ON(!ctx);
	}

7371 7372
	event->pmu = pmu;
	ret = pmu->event_init(event);
P
Peter Zijlstra 已提交
7373 7374 7375 7376

	if (ctx)
		perf_event_ctx_unlock(event->group_leader, ctx);

7377 7378 7379 7380 7381 7382
	if (ret)
		module_put(pmu->module);

	return ret;
}

7383 7384 7385 7386
struct pmu *perf_init_event(struct perf_event *event)
{
	struct pmu *pmu = NULL;
	int idx;
7387
	int ret;
7388 7389

	idx = srcu_read_lock(&pmus_srcu);
P
Peter Zijlstra 已提交
7390 7391 7392 7393

	rcu_read_lock();
	pmu = idr_find(&pmu_idr, event->attr.type);
	rcu_read_unlock();
7394
	if (pmu) {
7395
		ret = perf_try_init_event(pmu, event);
7396 7397
		if (ret)
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
7398
		goto unlock;
7399
	}
P
Peter Zijlstra 已提交
7400

7401
	list_for_each_entry_rcu(pmu, &pmus, entry) {
7402
		ret = perf_try_init_event(pmu, event);
7403
		if (!ret)
P
Peter Zijlstra 已提交
7404
			goto unlock;
7405

7406 7407
		if (ret != -ENOENT) {
			pmu = ERR_PTR(ret);
P
Peter Zijlstra 已提交
7408
			goto unlock;
7409
		}
7410
	}
P
Peter Zijlstra 已提交
7411 7412
	pmu = ERR_PTR(-ENOENT);
unlock:
7413
	srcu_read_unlock(&pmus_srcu, idx);
7414

7415
	return pmu;
7416 7417
}

7418 7419 7420 7421 7422 7423 7424 7425 7426
static void account_event_cpu(struct perf_event *event, int cpu)
{
	if (event->parent)
		return;

	if (is_cgroup_event(event))
		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
}

7427 7428
static void account_event(struct perf_event *event)
{
7429 7430 7431
	if (event->parent)
		return;

7432 7433 7434 7435 7436 7437 7438 7439
	if (event->attach_state & PERF_ATTACH_TASK)
		static_key_slow_inc(&perf_sched_events.key);
	if (event->attr.mmap || event->attr.mmap_data)
		atomic_inc(&nr_mmap_events);
	if (event->attr.comm)
		atomic_inc(&nr_comm_events);
	if (event->attr.task)
		atomic_inc(&nr_task_events);
7440 7441 7442 7443
	if (event->attr.freq) {
		if (atomic_inc_return(&nr_freq_events) == 1)
			tick_nohz_full_kick_all();
	}
7444
	if (has_branch_stack(event))
7445
		static_key_slow_inc(&perf_sched_events.key);
7446
	if (is_cgroup_event(event))
7447
		static_key_slow_inc(&perf_sched_events.key);
7448 7449

	account_event_cpu(event, event->cpu);
7450 7451
}

T
Thomas Gleixner 已提交
7452
/*
7453
 * Allocate and initialize a event structure
T
Thomas Gleixner 已提交
7454
 */
7455
static struct perf_event *
7456
perf_event_alloc(struct perf_event_attr *attr, int cpu,
7457 7458 7459
		 struct task_struct *task,
		 struct perf_event *group_leader,
		 struct perf_event *parent_event,
7460
		 perf_overflow_handler_t overflow_handler,
7461
		 void *context, int cgroup_fd)
T
Thomas Gleixner 已提交
7462
{
P
Peter Zijlstra 已提交
7463
	struct pmu *pmu;
7464 7465
	struct perf_event *event;
	struct hw_perf_event *hwc;
7466
	long err = -EINVAL;
T
Thomas Gleixner 已提交
7467

7468 7469 7470 7471 7472
	if ((unsigned)cpu >= nr_cpu_ids) {
		if (!task || cpu != -1)
			return ERR_PTR(-EINVAL);
	}

7473
	event = kzalloc(sizeof(*event), GFP_KERNEL);
7474
	if (!event)
7475
		return ERR_PTR(-ENOMEM);
T
Thomas Gleixner 已提交
7476

7477
	/*
7478
	 * Single events are their own group leaders, with an
7479 7480 7481
	 * empty sibling list:
	 */
	if (!group_leader)
7482
		group_leader = event;
7483

7484 7485
	mutex_init(&event->child_mutex);
	INIT_LIST_HEAD(&event->child_list);
7486

7487 7488 7489
	INIT_LIST_HEAD(&event->group_entry);
	INIT_LIST_HEAD(&event->event_entry);
	INIT_LIST_HEAD(&event->sibling_list);
7490
	INIT_LIST_HEAD(&event->rb_entry);
7491
	INIT_LIST_HEAD(&event->active_entry);
7492 7493
	INIT_HLIST_NODE(&event->hlist_entry);

7494

7495
	init_waitqueue_head(&event->waitq);
7496
	init_irq_work(&event->pending, perf_pending_event);
T
Thomas Gleixner 已提交
7497

7498
	mutex_init(&event->mmap_mutex);
7499

7500
	atomic_long_set(&event->refcount, 1);
7501 7502 7503 7504 7505
	event->cpu		= cpu;
	event->attr		= *attr;
	event->group_leader	= group_leader;
	event->pmu		= NULL;
	event->oncpu		= -1;
7506

7507
	event->parent		= parent_event;
7508

7509
	event->ns		= get_pid_ns(task_active_pid_ns(current));
7510
	event->id		= atomic64_inc_return(&perf_event_id);
7511

7512
	event->state		= PERF_EVENT_STATE_INACTIVE;
7513

7514 7515 7516
	if (task) {
		event->attach_state = PERF_ATTACH_TASK;
		/*
7517 7518 7519
		 * XXX pmu::event_init needs to know what task to account to
		 * and we cannot use the ctx information because we need the
		 * pmu before we get a ctx.
7520
		 */
7521
		event->hw.target = task;
7522 7523
	}

7524 7525 7526 7527
	event->clock = &local_clock;
	if (parent_event)
		event->clock = parent_event->clock;

7528
	if (!overflow_handler && parent_event) {
7529
		overflow_handler = parent_event->overflow_handler;
7530 7531
		context = parent_event->overflow_handler_context;
	}
7532

7533
	event->overflow_handler	= overflow_handler;
7534
	event->overflow_handler_context = context;
7535

J
Jiri Olsa 已提交
7536
	perf_event__state_init(event);
7537

7538
	pmu = NULL;
7539

7540
	hwc = &event->hw;
7541
	hwc->sample_period = attr->sample_period;
7542
	if (attr->freq && attr->sample_freq)
7543
		hwc->sample_period = 1;
7544
	hwc->last_period = hwc->sample_period;
7545

7546
	local64_set(&hwc->period_left, hwc->sample_period);
7547

7548
	/*
7549
	 * we currently do not support PERF_FORMAT_GROUP on inherited events
7550
	 */
7551
	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7552
		goto err_ns;
7553 7554 7555

	if (!has_branch_stack(event))
		event->attr.branch_sample_type = 0;
7556

7557 7558 7559 7560 7561 7562
	if (cgroup_fd != -1) {
		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
		if (err)
			goto err_ns;
	}

7563
	pmu = perf_init_event(event);
7564
	if (!pmu)
7565 7566
		goto err_ns;
	else if (IS_ERR(pmu)) {
7567
		err = PTR_ERR(pmu);
7568
		goto err_ns;
I
Ingo Molnar 已提交
7569
	}
7570

7571 7572 7573 7574
	err = exclusive_event_init(event);
	if (err)
		goto err_pmu;

7575
	if (!event->parent) {
7576 7577
		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
			err = get_callchain_buffers();
7578
			if (err)
7579
				goto err_per_task;
7580
		}
7581
	}
7582

7583
	return event;
7584

7585 7586 7587
err_per_task:
	exclusive_event_destroy(event);

7588 7589 7590
err_pmu:
	if (event->destroy)
		event->destroy(event);
7591
	module_put(pmu->module);
7592
err_ns:
7593 7594
	if (is_cgroup_event(event))
		perf_detach_cgroup(event);
7595 7596 7597 7598 7599
	if (event->ns)
		put_pid_ns(event->ns);
	kfree(event);

	return ERR_PTR(err);
T
Thomas Gleixner 已提交
7600 7601
}

7602 7603
static int perf_copy_attr(struct perf_event_attr __user *uattr,
			  struct perf_event_attr *attr)
7604 7605
{
	u32 size;
7606
	int ret;
7607 7608 7609 7610 7611 7612 7613 7614 7615 7616 7617 7618 7619 7620 7621 7622 7623 7624 7625 7626 7627 7628 7629 7630

	if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
		return -EFAULT;

	/*
	 * zero the full structure, so that a short copy will be nice.
	 */
	memset(attr, 0, sizeof(*attr));

	ret = get_user(size, &uattr->size);
	if (ret)
		return ret;

	if (size > PAGE_SIZE)	/* silly large */
		goto err_size;

	if (!size)		/* abi compat */
		size = PERF_ATTR_SIZE_VER0;

	if (size < PERF_ATTR_SIZE_VER0)
		goto err_size;

	/*
	 * If we're handed a bigger struct than we know of,
7631 7632 7633
	 * ensure all the unknown bits are 0 - i.e. new
	 * user-space does not rely on any kernel feature
	 * extensions we dont know about yet.
7634 7635
	 */
	if (size > sizeof(*attr)) {
7636 7637 7638
		unsigned char __user *addr;
		unsigned char __user *end;
		unsigned char val;
7639

7640 7641
		addr = (void __user *)uattr + sizeof(*attr);
		end  = (void __user *)uattr + size;
7642

7643
		for (; addr < end; addr++) {
7644 7645 7646 7647 7648 7649
			ret = get_user(val, addr);
			if (ret)
				return ret;
			if (val)
				goto err_size;
		}
7650
		size = sizeof(*attr);
7651 7652 7653 7654 7655 7656
	}

	ret = copy_from_user(attr, uattr, size);
	if (ret)
		return -EFAULT;

7657
	if (attr->__reserved_1)
7658 7659 7660 7661 7662 7663 7664 7665
		return -EINVAL;

	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
		return -EINVAL;

	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
		return -EINVAL;

7666 7667 7668 7669 7670 7671 7672 7673 7674 7675 7676 7677 7678 7679 7680 7681 7682 7683 7684 7685 7686 7687 7688 7689 7690 7691 7692 7693
	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
		u64 mask = attr->branch_sample_type;

		/* only using defined bits */
		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
			return -EINVAL;

		/* at least one branch bit must be set */
		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
			return -EINVAL;

		/* propagate priv level, when not set for branch */
		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {

			/* exclude_kernel checked on syscall entry */
			if (!attr->exclude_kernel)
				mask |= PERF_SAMPLE_BRANCH_KERNEL;

			if (!attr->exclude_user)
				mask |= PERF_SAMPLE_BRANCH_USER;

			if (!attr->exclude_hv)
				mask |= PERF_SAMPLE_BRANCH_HV;
			/*
			 * adjust user setting (for HW filter setup)
			 */
			attr->branch_sample_type = mask;
		}
7694 7695
		/* privileged levels capture (kernel, hv): check permissions */
		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
7696 7697
		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
7698
	}
7699

7700
	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
7701
		ret = perf_reg_validate(attr->sample_regs_user);
7702 7703 7704 7705 7706 7707 7708 7709 7710 7711 7712 7713 7714 7715 7716 7717 7718 7719
		if (ret)
			return ret;
	}

	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
		if (!arch_perf_have_user_stack_dump())
			return -ENOSYS;

		/*
		 * We have __u32 type for the size, but so far
		 * we can only use __u16 as maximum due to the
		 * __u16 sample size limit.
		 */
		if (attr->sample_stack_user >= USHRT_MAX)
			ret = -EINVAL;
		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
			ret = -EINVAL;
	}
7720

7721 7722
	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
		ret = perf_reg_validate(attr->sample_regs_intr);
7723 7724 7725 7726 7727 7728 7729 7730 7731
out:
	return ret;

err_size:
	put_user(sizeof(*attr), &uattr->size);
	ret = -E2BIG;
	goto out;
}

7732 7733
static int
perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
7734
{
7735
	struct ring_buffer *rb = NULL;
7736 7737
	int ret = -EINVAL;

7738
	if (!output_event)
7739 7740
		goto set;

7741 7742
	/* don't allow circular references */
	if (event == output_event)
7743 7744
		goto out;

7745 7746 7747 7748 7749 7750 7751
	/*
	 * Don't allow cross-cpu buffers
	 */
	if (output_event->cpu != event->cpu)
		goto out;

	/*
7752
	 * If its not a per-cpu rb, it must be the same task.
7753 7754 7755 7756
	 */
	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
		goto out;

7757 7758 7759 7760 7761 7762
	/*
	 * Mixing clocks in the same buffer is trouble you don't need.
	 */
	if (output_event->clock != event->clock)
		goto out;

7763 7764 7765 7766 7767 7768 7769
	/*
	 * If both events generate aux data, they must be on the same PMU
	 */
	if (has_aux(event) && has_aux(output_event) &&
	    event->pmu != output_event->pmu)
		goto out;

7770
set:
7771
	mutex_lock(&event->mmap_mutex);
7772 7773 7774
	/* Can't redirect output if we've got an active mmap() */
	if (atomic_read(&event->mmap_count))
		goto unlock;
7775

7776
	if (output_event) {
7777 7778 7779
		/* get the rb we want to redirect to */
		rb = ring_buffer_get(output_event);
		if (!rb)
7780
			goto unlock;
7781 7782
	}

7783
	ring_buffer_attach(event, rb);
7784

7785
	ret = 0;
7786 7787 7788
unlock:
	mutex_unlock(&event->mmap_mutex);

7789 7790 7791 7792
out:
	return ret;
}

P
Peter Zijlstra 已提交
7793 7794 7795 7796 7797 7798 7799 7800 7801
static void mutex_lock_double(struct mutex *a, struct mutex *b)
{
	if (b < a)
		swap(a, b);

	mutex_lock(a);
	mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
}

7802 7803 7804 7805 7806 7807 7808 7809 7810 7811 7812 7813 7814 7815 7816 7817 7818 7819 7820 7821 7822 7823 7824 7825 7826 7827 7828 7829 7830 7831 7832 7833 7834 7835 7836 7837 7838
static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
{
	bool nmi_safe = false;

	switch (clk_id) {
	case CLOCK_MONOTONIC:
		event->clock = &ktime_get_mono_fast_ns;
		nmi_safe = true;
		break;

	case CLOCK_MONOTONIC_RAW:
		event->clock = &ktime_get_raw_fast_ns;
		nmi_safe = true;
		break;

	case CLOCK_REALTIME:
		event->clock = &ktime_get_real_ns;
		break;

	case CLOCK_BOOTTIME:
		event->clock = &ktime_get_boot_ns;
		break;

	case CLOCK_TAI:
		event->clock = &ktime_get_tai_ns;
		break;

	default:
		return -EINVAL;
	}

	if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
		return -EINVAL;

	return 0;
}

T
Thomas Gleixner 已提交
7839
/**
7840
 * sys_perf_event_open - open a performance event, associate it to a task/cpu
I
Ingo Molnar 已提交
7841
 *
7842
 * @attr_uptr:	event_id type attributes for monitoring/sampling
T
Thomas Gleixner 已提交
7843
 * @pid:		target pid
I
Ingo Molnar 已提交
7844
 * @cpu:		target cpu
7845
 * @group_fd:		group leader event fd
T
Thomas Gleixner 已提交
7846
 */
7847 7848
SYSCALL_DEFINE5(perf_event_open,
		struct perf_event_attr __user *, attr_uptr,
7849
		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
T
Thomas Gleixner 已提交
7850
{
7851 7852
	struct perf_event *group_leader = NULL, *output_event = NULL;
	struct perf_event *event, *sibling;
7853
	struct perf_event_attr attr;
P
Peter Zijlstra 已提交
7854
	struct perf_event_context *ctx, *uninitialized_var(gctx);
7855
	struct file *event_file = NULL;
7856
	struct fd group = {NULL, 0};
M
Matt Helsley 已提交
7857
	struct task_struct *task = NULL;
7858
	struct pmu *pmu;
7859
	int event_fd;
7860
	int move_group = 0;
7861
	int err;
7862
	int f_flags = O_RDWR;
7863
	int cgroup_fd = -1;
T
Thomas Gleixner 已提交
7864

7865
	/* for future expandability... */
S
Stephane Eranian 已提交
7866
	if (flags & ~PERF_FLAG_ALL)
7867 7868
		return -EINVAL;

7869 7870 7871
	err = perf_copy_attr(attr_uptr, &attr);
	if (err)
		return err;
7872

7873 7874 7875 7876 7877
	if (!attr.exclude_kernel) {
		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
			return -EACCES;
	}

7878
	if (attr.freq) {
7879
		if (attr.sample_freq > sysctl_perf_event_sample_rate)
7880
			return -EINVAL;
7881 7882 7883
	} else {
		if (attr.sample_period & (1ULL << 63))
			return -EINVAL;
7884 7885
	}

S
Stephane Eranian 已提交
7886 7887 7888 7889 7890 7891 7892 7893 7894
	/*
	 * In cgroup mode, the pid argument is used to pass the fd
	 * opened to the cgroup directory in cgroupfs. The cpu argument
	 * designates the cpu on which to monitor threads from that
	 * cgroup.
	 */
	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
		return -EINVAL;

7895 7896 7897 7898
	if (flags & PERF_FLAG_FD_CLOEXEC)
		f_flags |= O_CLOEXEC;

	event_fd = get_unused_fd_flags(f_flags);
7899 7900 7901
	if (event_fd < 0)
		return event_fd;

7902
	if (group_fd != -1) {
7903 7904
		err = perf_fget_light(group_fd, &group);
		if (err)
7905
			goto err_fd;
7906
		group_leader = group.file->private_data;
7907 7908 7909 7910 7911 7912
		if (flags & PERF_FLAG_FD_OUTPUT)
			output_event = group_leader;
		if (flags & PERF_FLAG_FD_NO_GROUP)
			group_leader = NULL;
	}

S
Stephane Eranian 已提交
7913
	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
7914 7915 7916 7917 7918 7919 7920
		task = find_lively_task_by_vpid(pid);
		if (IS_ERR(task)) {
			err = PTR_ERR(task);
			goto err_group_fd;
		}
	}

7921 7922 7923 7924 7925 7926
	if (task && group_leader &&
	    group_leader->attr.inherit != attr.inherit) {
		err = -EINVAL;
		goto err_task;
	}

7927 7928
	get_online_cpus();

7929 7930 7931
	if (flags & PERF_FLAG_PID_CGROUP)
		cgroup_fd = pid;

7932
	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
7933
				 NULL, NULL, cgroup_fd);
7934 7935
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
7936
		goto err_cpus;
7937 7938
	}

7939 7940 7941 7942 7943 7944 7945
	if (is_sampling_event(event)) {
		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
			err = -ENOTSUPP;
			goto err_alloc;
		}
	}

7946 7947
	account_event(event);

7948 7949 7950 7951 7952
	/*
	 * Special case software events and allow them to be part of
	 * any hardware group.
	 */
	pmu = event->pmu;
7953

7954 7955 7956 7957 7958 7959
	if (attr.use_clockid) {
		err = perf_event_set_clock(event, attr.clockid);
		if (err)
			goto err_alloc;
	}

7960 7961 7962 7963 7964 7965 7966 7967 7968 7969 7970 7971 7972 7973 7974 7975 7976 7977 7978 7979 7980 7981
	if (group_leader &&
	    (is_software_event(event) != is_software_event(group_leader))) {
		if (is_software_event(event)) {
			/*
			 * If event and group_leader are not both a software
			 * event, and event is, then group leader is not.
			 *
			 * Allow the addition of software events to !software
			 * groups, this is safe because software events never
			 * fail to schedule.
			 */
			pmu = group_leader->pmu;
		} else if (is_software_event(group_leader) &&
			   (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
			/*
			 * In case the group is a pure software group, and we
			 * try to add a hardware event, move the whole group to
			 * the hardware context.
			 */
			move_group = 1;
		}
	}
7982 7983 7984 7985

	/*
	 * Get the target context (task or percpu):
	 */
7986
	ctx = find_get_context(pmu, task, event);
7987 7988
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
7989
		goto err_alloc;
7990 7991
	}

7992 7993 7994 7995 7996
	if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
		err = -EBUSY;
		goto err_context;
	}

7997 7998 7999 8000 8001
	if (task) {
		put_task_struct(task);
		task = NULL;
	}

I
Ingo Molnar 已提交
8002
	/*
8003
	 * Look up the group leader (we will attach this event to it):
8004
	 */
8005
	if (group_leader) {
8006
		err = -EINVAL;
8007 8008

		/*
I
Ingo Molnar 已提交
8009 8010 8011 8012
		 * Do not allow a recursive hierarchy (this new sibling
		 * becoming part of another group-sibling):
		 */
		if (group_leader->group_leader != group_leader)
8013
			goto err_context;
8014 8015 8016 8017 8018

		/* All events in a group should have the same clock */
		if (group_leader->clock != event->clock)
			goto err_context;

I
Ingo Molnar 已提交
8019 8020 8021
		/*
		 * Do not allow to attach to a group in a different
		 * task or CPU context:
8022
		 */
8023
		if (move_group) {
8024 8025 8026 8027 8028 8029 8030 8031 8032 8033 8034 8035 8036
			/*
			 * Make sure we're both on the same task, or both
			 * per-cpu events.
			 */
			if (group_leader->ctx->task != ctx->task)
				goto err_context;

			/*
			 * Make sure we're both events for the same CPU;
			 * grouping events for different CPUs is broken; since
			 * you can never concurrently schedule them anyhow.
			 */
			if (group_leader->cpu != event->cpu)
8037 8038 8039 8040 8041 8042
				goto err_context;
		} else {
			if (group_leader->ctx != ctx)
				goto err_context;
		}

8043 8044 8045
		/*
		 * Only a group leader can be exclusive or pinned
		 */
8046
		if (attr.exclusive || attr.pinned)
8047
			goto err_context;
8048 8049 8050 8051 8052
	}

	if (output_event) {
		err = perf_event_set_output(event, output_event);
		if (err)
8053
			goto err_context;
8054
	}
T
Thomas Gleixner 已提交
8055

8056 8057
	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
					f_flags);
8058 8059
	if (IS_ERR(event_file)) {
		err = PTR_ERR(event_file);
8060
		goto err_context;
8061
	}
8062

8063
	if (move_group) {
P
Peter Zijlstra 已提交
8064 8065 8066 8067 8068 8069 8070
		gctx = group_leader->ctx;

		/*
		 * See perf_event_ctx_lock() for comments on the details
		 * of swizzling perf_event::ctx.
		 */
		mutex_lock_double(&gctx->mutex, &ctx->mutex);
8071

8072
		perf_remove_from_context(group_leader, false);
J
Jiri Olsa 已提交
8073

8074 8075
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
8076
			perf_remove_from_context(sibling, false);
8077 8078
			put_ctx(gctx);
		}
P
Peter Zijlstra 已提交
8079 8080
	} else {
		mutex_lock(&ctx->mutex);
8081
	}
8082

8083
	WARN_ON_ONCE(ctx->parent_ctx);
8084 8085

	if (move_group) {
P
Peter Zijlstra 已提交
8086 8087 8088 8089
		/*
		 * Wait for everybody to stop referencing the events through
		 * the old lists, before installing it on new lists.
		 */
8090
		synchronize_rcu();
P
Peter Zijlstra 已提交
8091

8092 8093 8094 8095 8096 8097 8098 8099 8100 8101
		/*
		 * Install the group siblings before the group leader.
		 *
		 * Because a group leader will try and install the entire group
		 * (through the sibling list, which is still in-tact), we can
		 * end up with siblings installed in the wrong context.
		 *
		 * By installing siblings first we NO-OP because they're not
		 * reachable through the group lists.
		 */
8102 8103
		list_for_each_entry(sibling, &group_leader->sibling_list,
				    group_entry) {
8104
			perf_event__state_init(sibling);
8105
			perf_install_in_context(ctx, sibling, sibling->cpu);
8106 8107
			get_ctx(ctx);
		}
8108 8109 8110 8111 8112 8113 8114 8115 8116

		/*
		 * Removing from the context ends up with disabled
		 * event. What we want here is event in the initial
		 * startup state, ready to be add into new context.
		 */
		perf_event__state_init(group_leader);
		perf_install_in_context(ctx, group_leader, group_leader->cpu);
		get_ctx(ctx);
8117 8118
	}

8119 8120 8121 8122 8123 8124 8125
	if (!exclusive_event_installable(event, ctx)) {
		err = -EBUSY;
		mutex_unlock(&ctx->mutex);
		fput(event_file);
		goto err_context;
	}

8126
	perf_install_in_context(ctx, event, event->cpu);
8127
	perf_unpin_context(ctx);
P
Peter Zijlstra 已提交
8128 8129 8130 8131 8132

	if (move_group) {
		mutex_unlock(&gctx->mutex);
		put_ctx(gctx);
	}
8133
	mutex_unlock(&ctx->mutex);
8134

8135 8136
	put_online_cpus();

8137
	event->owner = current;
P
Peter Zijlstra 已提交
8138

8139 8140 8141
	mutex_lock(&current->perf_event_mutex);
	list_add_tail(&event->owner_entry, &current->perf_event_list);
	mutex_unlock(&current->perf_event_mutex);
8142

8143 8144 8145 8146
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(event);
8147
	perf_event__id_header_size(event);
8148

8149 8150 8151 8152 8153 8154
	/*
	 * Drop the reference on the group_event after placing the
	 * new event on the sibling_list. This ensures destruction
	 * of the group leader will find the pointer to itself in
	 * perf_group_detach().
	 */
8155
	fdput(group);
8156 8157
	fd_install(event_fd, event_file);
	return event_fd;
T
Thomas Gleixner 已提交
8158

8159
err_context:
8160
	perf_unpin_context(ctx);
8161
	put_ctx(ctx);
8162
err_alloc:
8163
	free_event(event);
8164
err_cpus:
8165
	put_online_cpus();
8166
err_task:
P
Peter Zijlstra 已提交
8167 8168
	if (task)
		put_task_struct(task);
8169
err_group_fd:
8170
	fdput(group);
8171 8172
err_fd:
	put_unused_fd(event_fd);
8173
	return err;
T
Thomas Gleixner 已提交
8174 8175
}

8176 8177 8178 8179 8180
/**
 * perf_event_create_kernel_counter
 *
 * @attr: attributes of the counter to create
 * @cpu: cpu in which the counter is bound
M
Matt Helsley 已提交
8181
 * @task: task to profile (NULL for percpu)
8182 8183 8184
 */
struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
M
Matt Helsley 已提交
8185
				 struct task_struct *task,
8186 8187
				 perf_overflow_handler_t overflow_handler,
				 void *context)
8188 8189
{
	struct perf_event_context *ctx;
8190
	struct perf_event *event;
8191
	int err;
8192

8193 8194 8195
	/*
	 * Get the target context (task or percpu):
	 */
8196

8197
	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8198
				 overflow_handler, context, -1);
8199 8200 8201 8202
	if (IS_ERR(event)) {
		err = PTR_ERR(event);
		goto err;
	}
8203

8204 8205 8206
	/* Mark owner so we could distinguish it from user events. */
	event->owner = EVENT_OWNER_KERNEL;

8207 8208
	account_event(event);

8209
	ctx = find_get_context(event->pmu, task, event);
8210 8211
	if (IS_ERR(ctx)) {
		err = PTR_ERR(ctx);
8212
		goto err_free;
8213
	}
8214 8215 8216

	WARN_ON_ONCE(ctx->parent_ctx);
	mutex_lock(&ctx->mutex);
8217 8218 8219 8220 8221 8222 8223 8224
	if (!exclusive_event_installable(event, ctx)) {
		mutex_unlock(&ctx->mutex);
		perf_unpin_context(ctx);
		put_ctx(ctx);
		err = -EBUSY;
		goto err_free;
	}

8225
	perf_install_in_context(ctx, event, cpu);
8226
	perf_unpin_context(ctx);
8227 8228 8229 8230
	mutex_unlock(&ctx->mutex);

	return event;

8231 8232 8233
err_free:
	free_event(event);
err:
8234
	return ERR_PTR(err);
8235
}
8236
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8237

8238 8239 8240 8241 8242 8243 8244 8245 8246 8247
void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
{
	struct perf_event_context *src_ctx;
	struct perf_event_context *dst_ctx;
	struct perf_event *event, *tmp;
	LIST_HEAD(events);

	src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
	dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;

P
Peter Zijlstra 已提交
8248 8249 8250 8251 8252
	/*
	 * See perf_event_ctx_lock() for comments on the details
	 * of swizzling perf_event::ctx.
	 */
	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8253 8254
	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
				 event_entry) {
8255
		perf_remove_from_context(event, false);
8256
		unaccount_event_cpu(event, src_cpu);
8257
		put_ctx(src_ctx);
8258
		list_add(&event->migrate_entry, &events);
8259 8260
	}

8261 8262 8263
	/*
	 * Wait for the events to quiesce before re-instating them.
	 */
8264 8265
	synchronize_rcu();

8266 8267 8268 8269 8270 8271 8272 8273 8274 8275 8276 8277 8278 8279 8280 8281 8282 8283 8284 8285 8286 8287 8288 8289
	/*
	 * Re-instate events in 2 passes.
	 *
	 * Skip over group leaders and only install siblings on this first
	 * pass, siblings will not get enabled without a leader, however a
	 * leader will enable its siblings, even if those are still on the old
	 * context.
	 */
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		if (event->group_leader == event)
			continue;

		list_del(&event->migrate_entry);
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
		account_event_cpu(event, dst_cpu);
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}

	/*
	 * Once all the siblings are setup properly, install the group leaders
	 * to make it go.
	 */
8290 8291
	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
		list_del(&event->migrate_entry);
8292 8293
		if (event->state >= PERF_EVENT_STATE_OFF)
			event->state = PERF_EVENT_STATE_INACTIVE;
8294
		account_event_cpu(event, dst_cpu);
8295 8296 8297 8298
		perf_install_in_context(dst_ctx, event, dst_cpu);
		get_ctx(dst_ctx);
	}
	mutex_unlock(&dst_ctx->mutex);
P
Peter Zijlstra 已提交
8299
	mutex_unlock(&src_ctx->mutex);
8300 8301 8302
}
EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);

8303
static void sync_child_event(struct perf_event *child_event,
8304
			       struct task_struct *child)
8305
{
8306
	struct perf_event *parent_event = child_event->parent;
8307
	u64 child_val;
8308

8309 8310
	if (child_event->attr.inherit_stat)
		perf_event_read_event(child_event, child);
8311

P
Peter Zijlstra 已提交
8312
	child_val = perf_event_count(child_event);
8313 8314 8315 8316

	/*
	 * Add back the child's count to the parent's count:
	 */
8317
	atomic64_add(child_val, &parent_event->child_count);
8318 8319 8320 8321
	atomic64_add(child_event->total_time_enabled,
		     &parent_event->child_total_time_enabled);
	atomic64_add(child_event->total_time_running,
		     &parent_event->child_total_time_running);
8322 8323

	/*
8324
	 * Remove this event from the parent's list
8325
	 */
8326 8327 8328 8329
	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
	mutex_lock(&parent_event->child_mutex);
	list_del_init(&child_event->child_list);
	mutex_unlock(&parent_event->child_mutex);
8330

8331 8332 8333 8334 8335 8336
	/*
	 * Make sure user/parent get notified, that we just
	 * lost one event.
	 */
	perf_event_wakeup(parent_event);

8337
	/*
8338
	 * Release the parent event, if this was the last
8339 8340
	 * reference to it.
	 */
8341
	put_event(parent_event);
8342 8343
}

8344
static void
8345 8346
__perf_event_exit_task(struct perf_event *child_event,
			 struct perf_event_context *child_ctx,
8347
			 struct task_struct *child)
8348
{
8349 8350 8351 8352 8353 8354 8355 8356 8357 8358 8359 8360 8361
	/*
	 * Do not destroy the 'original' grouping; because of the context
	 * switch optimization the original events could've ended up in a
	 * random child task.
	 *
	 * If we were to destroy the original group, all group related
	 * operations would cease to function properly after this random
	 * child dies.
	 *
	 * Do destroy all inherited groups, we don't care about those
	 * and being thorough is better.
	 */
	perf_remove_from_context(child_event, !!child_event->parent);
8362

8363
	/*
8364
	 * It can happen that the parent exits first, and has events
8365
	 * that are still around due to the child reference. These
8366
	 * events need to be zapped.
8367
	 */
8368
	if (child_event->parent) {
8369 8370
		sync_child_event(child_event, child);
		free_event(child_event);
8371 8372 8373
	} else {
		child_event->state = PERF_EVENT_STATE_EXIT;
		perf_event_wakeup(child_event);
8374
	}
8375 8376
}

P
Peter Zijlstra 已提交
8377
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8378
{
8379
	struct perf_event *child_event, *next;
8380
	struct perf_event_context *child_ctx, *clone_ctx = NULL;
8381
	unsigned long flags;
8382

P
Peter Zijlstra 已提交
8383
	if (likely(!child->perf_event_ctxp[ctxn])) {
8384
		perf_event_task(child, NULL, 0);
8385
		return;
P
Peter Zijlstra 已提交
8386
	}
8387

8388
	local_irq_save(flags);
8389 8390 8391 8392 8393 8394
	/*
	 * We can't reschedule here because interrupts are disabled,
	 * and either child is current or it is a task that can't be
	 * scheduled, so we are now safe from rescheduling changing
	 * our context.
	 */
8395
	child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8396 8397 8398

	/*
	 * Take the context lock here so that if find_get_context is
8399
	 * reading child->perf_event_ctxp, we wait until it has
8400 8401
	 * incremented the context's refcount before we do put_ctx below.
	 */
8402
	raw_spin_lock(&child_ctx->lock);
8403
	task_ctx_sched_out(child_ctx);
P
Peter Zijlstra 已提交
8404
	child->perf_event_ctxp[ctxn] = NULL;
8405

8406 8407 8408
	/*
	 * If this context is a clone; unclone it so it can't get
	 * swapped to another process while we're removing all
8409
	 * the events from it.
8410
	 */
8411
	clone_ctx = unclone_ctx(child_ctx);
8412
	update_context_time(child_ctx);
8413
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
8414

8415 8416
	if (clone_ctx)
		put_ctx(clone_ctx);
8417

P
Peter Zijlstra 已提交
8418
	/*
8419 8420 8421
	 * Report the task dead after unscheduling the events so that we
	 * won't get any samples after PERF_RECORD_EXIT. We can however still
	 * get a few PERF_RECORD_READ events.
P
Peter Zijlstra 已提交
8422
	 */
8423
	perf_event_task(child, child_ctx, 0);
8424

8425 8426 8427
	/*
	 * We can recurse on the same lock type through:
	 *
8428 8429
	 *   __perf_event_exit_task()
	 *     sync_child_event()
8430 8431
	 *       put_event()
	 *         mutex_lock(&ctx->mutex)
8432 8433 8434
	 *
	 * But since its the parent context it won't be the same instance.
	 */
8435
	mutex_lock(&child_ctx->mutex);
8436

8437
	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8438
		__perf_event_exit_task(child_event, child_ctx, child);
8439

8440 8441 8442
	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
8443 8444
}

P
Peter Zijlstra 已提交
8445 8446 8447 8448 8449
/*
 * When a child task exits, feed back event values to parent events.
 */
void perf_event_exit_task(struct task_struct *child)
{
P
Peter Zijlstra 已提交
8450
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
8451 8452
	int ctxn;

P
Peter Zijlstra 已提交
8453 8454 8455 8456 8457 8458 8459 8460 8461 8462 8463 8464 8465 8466 8467
	mutex_lock(&child->perf_event_mutex);
	list_for_each_entry_safe(event, tmp, &child->perf_event_list,
				 owner_entry) {
		list_del_init(&event->owner_entry);

		/*
		 * Ensure the list deletion is visible before we clear
		 * the owner, closes a race against perf_release() where
		 * we need to serialize on the owner->perf_event_mutex.
		 */
		smp_wmb();
		event->owner = NULL;
	}
	mutex_unlock(&child->perf_event_mutex);

P
Peter Zijlstra 已提交
8468 8469 8470 8471
	for_each_task_context_nr(ctxn)
		perf_event_exit_task_context(child, ctxn);
}

8472 8473 8474 8475 8476 8477 8478 8479 8480 8481 8482 8483
static void perf_free_event(struct perf_event *event,
			    struct perf_event_context *ctx)
{
	struct perf_event *parent = event->parent;

	if (WARN_ON_ONCE(!parent))
		return;

	mutex_lock(&parent->child_mutex);
	list_del_init(&event->child_list);
	mutex_unlock(&parent->child_mutex);

8484
	put_event(parent);
8485

P
Peter Zijlstra 已提交
8486
	raw_spin_lock_irq(&ctx->lock);
8487
	perf_group_detach(event);
8488
	list_del_event(event, ctx);
P
Peter Zijlstra 已提交
8489
	raw_spin_unlock_irq(&ctx->lock);
8490 8491 8492
	free_event(event);
}

8493
/*
P
Peter Zijlstra 已提交
8494
 * Free an unexposed, unused context as created by inheritance by
P
Peter Zijlstra 已提交
8495
 * perf_event_init_task below, used by fork() in case of fail.
P
Peter Zijlstra 已提交
8496 8497 8498
 *
 * Not all locks are strictly required, but take them anyway to be nice and
 * help out with the lockdep assertions.
8499
 */
8500
void perf_event_free_task(struct task_struct *task)
8501
{
P
Peter Zijlstra 已提交
8502
	struct perf_event_context *ctx;
8503
	struct perf_event *event, *tmp;
P
Peter Zijlstra 已提交
8504
	int ctxn;
8505

P
Peter Zijlstra 已提交
8506 8507 8508 8509
	for_each_task_context_nr(ctxn) {
		ctx = task->perf_event_ctxp[ctxn];
		if (!ctx)
			continue;
8510

P
Peter Zijlstra 已提交
8511
		mutex_lock(&ctx->mutex);
8512
again:
P
Peter Zijlstra 已提交
8513 8514 8515
		list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
				group_entry)
			perf_free_event(event, ctx);
8516

P
Peter Zijlstra 已提交
8517 8518 8519
		list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
				group_entry)
			perf_free_event(event, ctx);
8520

P
Peter Zijlstra 已提交
8521 8522 8523
		if (!list_empty(&ctx->pinned_groups) ||
				!list_empty(&ctx->flexible_groups))
			goto again;
8524

P
Peter Zijlstra 已提交
8525
		mutex_unlock(&ctx->mutex);
8526

P
Peter Zijlstra 已提交
8527 8528
		put_ctx(ctx);
	}
8529 8530
}

8531 8532 8533 8534 8535 8536 8537 8538
void perf_event_delayed_put(struct task_struct *task)
{
	int ctxn;

	for_each_task_context_nr(ctxn)
		WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
}

P
Peter Zijlstra 已提交
8539 8540 8541 8542 8543 8544 8545 8546 8547 8548 8549
/*
 * inherit a event from parent task to child task:
 */
static struct perf_event *
inherit_event(struct perf_event *parent_event,
	      struct task_struct *parent,
	      struct perf_event_context *parent_ctx,
	      struct task_struct *child,
	      struct perf_event *group_leader,
	      struct perf_event_context *child_ctx)
{
8550
	enum perf_event_active_state parent_state = parent_event->state;
P
Peter Zijlstra 已提交
8551
	struct perf_event *child_event;
8552
	unsigned long flags;
P
Peter Zijlstra 已提交
8553 8554 8555 8556 8557 8558 8559 8560 8561 8562 8563 8564

	/*
	 * Instead of creating recursive hierarchies of events,
	 * we link inherited events back to the original parent,
	 * which has a filp for sure, which we use as the reference
	 * count:
	 */
	if (parent_event->parent)
		parent_event = parent_event->parent;

	child_event = perf_event_alloc(&parent_event->attr,
					   parent_event->cpu,
8565
					   child,
P
Peter Zijlstra 已提交
8566
					   group_leader, parent_event,
8567
					   NULL, NULL, -1);
P
Peter Zijlstra 已提交
8568 8569
	if (IS_ERR(child_event))
		return child_event;
8570

8571 8572
	if (is_orphaned_event(parent_event) ||
	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
8573 8574 8575 8576
		free_event(child_event);
		return NULL;
	}

P
Peter Zijlstra 已提交
8577 8578 8579 8580 8581 8582 8583
	get_ctx(child_ctx);

	/*
	 * Make the child state follow the state of the parent event,
	 * not its attr.disabled bit.  We hold the parent's mutex,
	 * so we won't race with perf_event_{en, dis}able_family.
	 */
8584
	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
P
Peter Zijlstra 已提交
8585 8586 8587 8588 8589 8590 8591 8592 8593 8594 8595 8596 8597 8598 8599 8600
		child_event->state = PERF_EVENT_STATE_INACTIVE;
	else
		child_event->state = PERF_EVENT_STATE_OFF;

	if (parent_event->attr.freq) {
		u64 sample_period = parent_event->hw.sample_period;
		struct hw_perf_event *hwc = &child_event->hw;

		hwc->sample_period = sample_period;
		hwc->last_period   = sample_period;

		local64_set(&hwc->period_left, sample_period);
	}

	child_event->ctx = child_ctx;
	child_event->overflow_handler = parent_event->overflow_handler;
8601 8602
	child_event->overflow_handler_context
		= parent_event->overflow_handler_context;
P
Peter Zijlstra 已提交
8603

8604 8605 8606 8607
	/*
	 * Precalculate sample_data sizes
	 */
	perf_event__header_size(child_event);
8608
	perf_event__id_header_size(child_event);
8609

P
Peter Zijlstra 已提交
8610 8611 8612
	/*
	 * Link it up in the child's context:
	 */
8613
	raw_spin_lock_irqsave(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
8614
	add_event_to_ctx(child_event, child_ctx);
8615
	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
P
Peter Zijlstra 已提交
8616 8617 8618 8619 8620 8621 8622 8623 8624 8625 8626 8627 8628 8629 8630 8631 8632 8633 8634 8635 8636 8637 8638 8639 8640 8641 8642 8643 8644 8645 8646 8647 8648

	/*
	 * Link this into the parent event's child list
	 */
	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
	mutex_lock(&parent_event->child_mutex);
	list_add_tail(&child_event->child_list, &parent_event->child_list);
	mutex_unlock(&parent_event->child_mutex);

	return child_event;
}

static int inherit_group(struct perf_event *parent_event,
	      struct task_struct *parent,
	      struct perf_event_context *parent_ctx,
	      struct task_struct *child,
	      struct perf_event_context *child_ctx)
{
	struct perf_event *leader;
	struct perf_event *sub;
	struct perf_event *child_ctr;

	leader = inherit_event(parent_event, parent, parent_ctx,
				 child, NULL, child_ctx);
	if (IS_ERR(leader))
		return PTR_ERR(leader);
	list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
		child_ctr = inherit_event(sub, parent, parent_ctx,
					    child, leader, child_ctx);
		if (IS_ERR(child_ctr))
			return PTR_ERR(child_ctr);
	}
	return 0;
8649 8650 8651 8652 8653
}

static int
inherit_task_group(struct perf_event *event, struct task_struct *parent,
		   struct perf_event_context *parent_ctx,
P
Peter Zijlstra 已提交
8654
		   struct task_struct *child, int ctxn,
8655 8656 8657
		   int *inherited_all)
{
	int ret;
P
Peter Zijlstra 已提交
8658
	struct perf_event_context *child_ctx;
8659 8660 8661 8662

	if (!event->attr.inherit) {
		*inherited_all = 0;
		return 0;
8663 8664
	}

8665
	child_ctx = child->perf_event_ctxp[ctxn];
8666 8667 8668 8669 8670 8671 8672
	if (!child_ctx) {
		/*
		 * This is executed from the parent task context, so
		 * inherit events that have been marked for cloning.
		 * First allocate and initialize a context for the
		 * child.
		 */
8673

8674
		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
8675 8676
		if (!child_ctx)
			return -ENOMEM;
8677

P
Peter Zijlstra 已提交
8678
		child->perf_event_ctxp[ctxn] = child_ctx;
8679 8680 8681 8682 8683 8684 8685 8686 8687
	}

	ret = inherit_group(event, parent, parent_ctx,
			    child, child_ctx);

	if (ret)
		*inherited_all = 0;

	return ret;
8688 8689
}

8690
/*
8691
 * Initialize the perf_event context in task_struct
8692
 */
8693
static int perf_event_init_context(struct task_struct *child, int ctxn)
8694
{
8695
	struct perf_event_context *child_ctx, *parent_ctx;
8696 8697
	struct perf_event_context *cloned_ctx;
	struct perf_event *event;
8698
	struct task_struct *parent = current;
8699
	int inherited_all = 1;
8700
	unsigned long flags;
8701
	int ret = 0;
8702

P
Peter Zijlstra 已提交
8703
	if (likely(!parent->perf_event_ctxp[ctxn]))
8704 8705
		return 0;

8706
	/*
8707 8708
	 * If the parent's context is a clone, pin it so it won't get
	 * swapped under us.
8709
	 */
P
Peter Zijlstra 已提交
8710
	parent_ctx = perf_pin_task_context(parent, ctxn);
8711 8712
	if (!parent_ctx)
		return 0;
8713

8714 8715 8716 8717 8718 8719 8720
	/*
	 * No need to check if parent_ctx != NULL here; since we saw
	 * it non-NULL earlier, the only reason for it to become NULL
	 * is if we exit, and since we're currently in the middle of
	 * a fork we can't be exiting at the same time.
	 */

8721 8722 8723 8724
	/*
	 * Lock the parent list. No need to lock the child - not PID
	 * hashed yet and not running, so nobody can access it.
	 */
8725
	mutex_lock(&parent_ctx->mutex);
8726 8727 8728 8729 8730

	/*
	 * We dont have to disable NMIs - we are only looking at
	 * the list, not manipulating it:
	 */
8731
	list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
P
Peter Zijlstra 已提交
8732 8733
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
8734 8735 8736
		if (ret)
			break;
	}
8737

8738 8739 8740 8741 8742 8743 8744 8745 8746
	/*
	 * We can't hold ctx->lock when iterating the ->flexible_group list due
	 * to allocations, but we need to prevent rotation because
	 * rotate_ctx() will change the list from interrupt context.
	 */
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 1;
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);

8747
	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
P
Peter Zijlstra 已提交
8748 8749
		ret = inherit_task_group(event, parent, parent_ctx,
					 child, ctxn, &inherited_all);
8750
		if (ret)
8751
			break;
8752 8753
	}

8754 8755 8756
	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
	parent_ctx->rotate_disable = 0;

P
Peter Zijlstra 已提交
8757
	child_ctx = child->perf_event_ctxp[ctxn];
8758

8759
	if (child_ctx && inherited_all) {
8760 8761 8762
		/*
		 * Mark the child context as a clone of the parent
		 * context, or of whatever the parent is a clone of.
P
Peter Zijlstra 已提交
8763 8764 8765
		 *
		 * Note that if the parent is a clone, the holding of
		 * parent_ctx->lock avoids it from being uncloned.
8766
		 */
P
Peter Zijlstra 已提交
8767
		cloned_ctx = parent_ctx->parent_ctx;
8768 8769
		if (cloned_ctx) {
			child_ctx->parent_ctx = cloned_ctx;
8770
			child_ctx->parent_gen = parent_ctx->parent_gen;
8771 8772 8773 8774 8775
		} else {
			child_ctx->parent_ctx = parent_ctx;
			child_ctx->parent_gen = parent_ctx->generation;
		}
		get_ctx(child_ctx->parent_ctx);
8776 8777
	}

P
Peter Zijlstra 已提交
8778
	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
8779
	mutex_unlock(&parent_ctx->mutex);
8780

8781
	perf_unpin_context(parent_ctx);
8782
	put_ctx(parent_ctx);
8783

8784
	return ret;
8785 8786
}

P
Peter Zijlstra 已提交
8787 8788 8789 8790 8791 8792 8793
/*
 * Initialize the perf_event context in task_struct
 */
int perf_event_init_task(struct task_struct *child)
{
	int ctxn, ret;

8794 8795 8796 8797
	memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
	mutex_init(&child->perf_event_mutex);
	INIT_LIST_HEAD(&child->perf_event_list);

P
Peter Zijlstra 已提交
8798 8799
	for_each_task_context_nr(ctxn) {
		ret = perf_event_init_context(child, ctxn);
P
Peter Zijlstra 已提交
8800 8801
		if (ret) {
			perf_event_free_task(child);
P
Peter Zijlstra 已提交
8802
			return ret;
P
Peter Zijlstra 已提交
8803
		}
P
Peter Zijlstra 已提交
8804 8805 8806 8807 8808
	}

	return 0;
}

8809 8810
static void __init perf_event_init_all_cpus(void)
{
8811
	struct swevent_htable *swhash;
8812 8813 8814
	int cpu;

	for_each_possible_cpu(cpu) {
8815 8816
		swhash = &per_cpu(swevent_htable, cpu);
		mutex_init(&swhash->hlist_mutex);
8817
		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
8818 8819 8820
	}
}

8821
static void perf_event_init_cpu(int cpu)
T
Thomas Gleixner 已提交
8822
{
P
Peter Zijlstra 已提交
8823
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
T
Thomas Gleixner 已提交
8824

8825
	mutex_lock(&swhash->hlist_mutex);
8826
	swhash->online = true;
8827
	if (swhash->hlist_refcount > 0) {
8828 8829
		struct swevent_hlist *hlist;

8830 8831 8832
		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
		WARN_ON(!hlist);
		rcu_assign_pointer(swhash->swevent_hlist, hlist);
8833
	}
8834
	mutex_unlock(&swhash->hlist_mutex);
T
Thomas Gleixner 已提交
8835 8836
}

P
Peter Zijlstra 已提交
8837
#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
P
Peter Zijlstra 已提交
8838
static void __perf_event_exit_context(void *__info)
T
Thomas Gleixner 已提交
8839
{
8840
	struct remove_event re = { .detach_group = true };
P
Peter Zijlstra 已提交
8841
	struct perf_event_context *ctx = __info;
T
Thomas Gleixner 已提交
8842

P
Peter Zijlstra 已提交
8843
	rcu_read_lock();
8844 8845
	list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
		__perf_remove_from_context(&re);
P
Peter Zijlstra 已提交
8846
	rcu_read_unlock();
T
Thomas Gleixner 已提交
8847
}
P
Peter Zijlstra 已提交
8848 8849 8850 8851 8852 8853 8854 8855 8856

static void perf_event_exit_cpu_context(int cpu)
{
	struct perf_event_context *ctx;
	struct pmu *pmu;
	int idx;

	idx = srcu_read_lock(&pmus_srcu);
	list_for_each_entry_rcu(pmu, &pmus, entry) {
8857
		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
P
Peter Zijlstra 已提交
8858 8859 8860 8861 8862 8863 8864 8865

		mutex_lock(&ctx->mutex);
		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
		mutex_unlock(&ctx->mutex);
	}
	srcu_read_unlock(&pmus_srcu, idx);
}

8866
static void perf_event_exit_cpu(int cpu)
T
Thomas Gleixner 已提交
8867
{
8868
	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8869

P
Peter Zijlstra 已提交
8870 8871
	perf_event_exit_cpu_context(cpu);

8872
	mutex_lock(&swhash->hlist_mutex);
8873
	swhash->online = false;
8874 8875
	swevent_hlist_release(swhash);
	mutex_unlock(&swhash->hlist_mutex);
T
Thomas Gleixner 已提交
8876 8877
}
#else
8878
static inline void perf_event_exit_cpu(int cpu) { }
T
Thomas Gleixner 已提交
8879 8880
#endif

P
Peter Zijlstra 已提交
8881 8882 8883 8884 8885 8886 8887 8888 8889 8890 8891 8892 8893 8894 8895 8896 8897 8898 8899 8900
static int
perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
{
	int cpu;

	for_each_online_cpu(cpu)
		perf_event_exit_cpu(cpu);

	return NOTIFY_OK;
}

/*
 * Run the perf reboot notifier at the very last possible moment so that
 * the generic watchdog code runs as long as possible.
 */
static struct notifier_block perf_reboot_notifier = {
	.notifier_call = perf_reboot,
	.priority = INT_MIN,
};

8901
static int
T
Thomas Gleixner 已提交
8902 8903 8904 8905
perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
{
	unsigned int cpu = (long)hcpu;

8906
	switch (action & ~CPU_TASKS_FROZEN) {
T
Thomas Gleixner 已提交
8907 8908

	case CPU_UP_PREPARE:
P
Peter Zijlstra 已提交
8909
	case CPU_DOWN_FAILED:
8910
		perf_event_init_cpu(cpu);
T
Thomas Gleixner 已提交
8911 8912
		break;

P
Peter Zijlstra 已提交
8913
	case CPU_UP_CANCELED:
T
Thomas Gleixner 已提交
8914
	case CPU_DOWN_PREPARE:
8915
		perf_event_exit_cpu(cpu);
T
Thomas Gleixner 已提交
8916 8917 8918 8919 8920 8921 8922 8923
		break;
	default:
		break;
	}

	return NOTIFY_OK;
}

8924
void __init perf_event_init(void)
T
Thomas Gleixner 已提交
8925
{
8926 8927
	int ret;

P
Peter Zijlstra 已提交
8928 8929
	idr_init(&pmu_idr);

8930
	perf_event_init_all_cpus();
8931
	init_srcu_struct(&pmus_srcu);
P
Peter Zijlstra 已提交
8932 8933 8934
	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
	perf_pmu_register(&perf_cpu_clock, NULL, -1);
	perf_pmu_register(&perf_task_clock, NULL, -1);
8935 8936
	perf_tp_register();
	perf_cpu_notifier(perf_cpu_notify);
P
Peter Zijlstra 已提交
8937
	register_reboot_notifier(&perf_reboot_notifier);
8938 8939 8940

	ret = init_hw_breakpoint();
	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
8941 8942 8943

	/* do not patch jump label more than once per second */
	jump_label_rate_limit(&perf_sched_events, HZ);
8944 8945 8946 8947 8948 8949 8950

	/*
	 * Build time assertion that we keep the data_head at the intended
	 * location.  IOW, validation we got the __reserved[] size right.
	 */
	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
		     != 1024);
T
Thomas Gleixner 已提交
8951
}
P
Peter Zijlstra 已提交
8952

8953 8954 8955 8956 8957 8958 8959 8960 8961 8962 8963 8964
ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
			      char *page)
{
	struct perf_pmu_events_attr *pmu_attr =
		container_of(attr, struct perf_pmu_events_attr, attr);

	if (pmu_attr->event_str)
		return sprintf(page, "%s\n", pmu_attr->event_str);

	return 0;
}

P
Peter Zijlstra 已提交
8965 8966 8967 8968 8969 8970 8971 8972 8973 8974 8975 8976 8977 8978 8979 8980 8981 8982 8983 8984 8985 8986 8987 8988 8989 8990 8991
static int __init perf_event_sysfs_init(void)
{
	struct pmu *pmu;
	int ret;

	mutex_lock(&pmus_lock);

	ret = bus_register(&pmu_bus);
	if (ret)
		goto unlock;

	list_for_each_entry(pmu, &pmus, entry) {
		if (!pmu->name || pmu->type < 0)
			continue;

		ret = pmu_dev_alloc(pmu);
		WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
	}
	pmu_bus_running = 1;
	ret = 0;

unlock:
	mutex_unlock(&pmus_lock);

	return ret;
}
device_initcall(perf_event_sysfs_init);
S
Stephane Eranian 已提交
8992 8993

#ifdef CONFIG_CGROUP_PERF
8994 8995
static struct cgroup_subsys_state *
perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
S
Stephane Eranian 已提交
8996 8997 8998
{
	struct perf_cgroup *jc;

8999
	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
S
Stephane Eranian 已提交
9000 9001 9002 9003 9004 9005 9006 9007 9008 9009 9010 9011
	if (!jc)
		return ERR_PTR(-ENOMEM);

	jc->info = alloc_percpu(struct perf_cgroup_info);
	if (!jc->info) {
		kfree(jc);
		return ERR_PTR(-ENOMEM);
	}

	return &jc->css;
}

9012
static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
S
Stephane Eranian 已提交
9013
{
9014 9015
	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);

S
Stephane Eranian 已提交
9016 9017 9018 9019 9020 9021 9022 9023 9024 9025 9026
	free_percpu(jc->info);
	kfree(jc);
}

static int __perf_cgroup_move(void *info)
{
	struct task_struct *task = info;
	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
	return 0;
}

9027 9028
static void perf_cgroup_attach(struct cgroup_subsys_state *css,
			       struct cgroup_taskset *tset)
S
Stephane Eranian 已提交
9029
{
9030 9031
	struct task_struct *task;

9032
	cgroup_taskset_for_each(task, tset)
9033
		task_function_call(task, __perf_cgroup_move, task);
S
Stephane Eranian 已提交
9034 9035
}

9036 9037
static void perf_cgroup_exit(struct cgroup_subsys_state *css,
			     struct cgroup_subsys_state *old_css,
9038
			     struct task_struct *task)
S
Stephane Eranian 已提交
9039 9040 9041 9042 9043 9044 9045 9046 9047
{
	/*
	 * cgroup_exit() is called in the copy_process() failure path.
	 * Ignore this case since the task hasn't ran yet, this avoids
	 * trying to poke a half freed task state from generic code.
	 */
	if (!(task->flags & PF_EXITING))
		return;

9048
	task_function_call(task, __perf_cgroup_move, task);
S
Stephane Eranian 已提交
9049 9050
}

9051
struct cgroup_subsys perf_event_cgrp_subsys = {
9052 9053
	.css_alloc	= perf_cgroup_css_alloc,
	.css_free	= perf_cgroup_css_free,
9054
	.exit		= perf_cgroup_exit,
9055
	.attach		= perf_cgroup_attach,
S
Stephane Eranian 已提交
9056 9057
};
#endif /* CONFIG_CGROUP_PERF */