1/*
   2 * Performance events core code:
   3 *
   4 *  Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
   5 *  Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
   6 *  Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
   7 *  Copyright  ©  2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
   8 *
   9 * For licensing details see kernel-base/COPYING
  10 */
  11
  12#include <linux/fs.h>
  13#include <linux/mm.h>
  14#include <linux/cpu.h>
  15#include <linux/smp.h>
  16#include <linux/idr.h>
  17#include <linux/file.h>
  18#include <linux/poll.h>
  19#include <linux/slab.h>
  20#include <linux/hash.h>
  21#include <linux/tick.h>
  22#include <linux/sysfs.h>
  23#include <linux/dcache.h>
  24#include <linux/percpu.h>
  25#include <linux/ptrace.h>
  26#include <linux/reboot.h>
  27#include <linux/vmstat.h>
  28#include <linux/device.h>
  29#include <linux/export.h>
  30#include <linux/vmalloc.h>
  31#include <linux/hardirq.h>
  32#include <linux/rculist.h>
  33#include <linux/uaccess.h>
  34#include <linux/syscalls.h>
  35#include <linux/anon_inodes.h>
  36#include <linux/kernel_stat.h>
  37#include <linux/cgroup.h>
  38#include <linux/perf_event.h>
  39#include <linux/trace_events.h>
  40#include <linux/hw_breakpoint.h>
  41#include <linux/mm_types.h>
  42#include <linux/module.h>
  43#include <linux/mman.h>
  44#include <linux/compat.h>
  45#include <linux/bpf.h>
  46#include <linux/filter.h>
  47
  48#include "internal.h"
  49
  50#include <asm/irq_regs.h>
  51
  52typedef int (*remote_function_f)(void *);
  53
  54struct remote_function_call {
  55	struct task_struct	*p;
  56	remote_function_f	func;
  57	void			*info;
  58	int			ret;
  59};
  60
  61static void remote_function(void *data)
  62{
  63	struct remote_function_call *tfc = data;
  64	struct task_struct *p = tfc->p;
  65
  66	if (p) {
  67		/* -EAGAIN */
  68		if (task_cpu(p) != smp_processor_id())
  69			return;
  70
  71		/*
  72		 * Now that we're on right CPU with IRQs disabled, we can test
  73		 * if we hit the right task without races.
  74		 */
  75
  76		tfc->ret = -ESRCH; /* No such (running) process */
  77		if (p != current)
  78			return;
  79	}
  80
  81	tfc->ret = tfc->func(tfc->info);
  82}
  83
  84/**
  85 * task_function_call - call a function on the cpu on which a task runs
  86 * @p:		the task to evaluate
  87 * @func:	the function to be called
  88 * @info:	the function call argument
  89 *
  90 * Calls the function @func when the task is currently running. This might
  91 * be on the current CPU, which just calls the function directly
  92 *
  93 * returns: @func return value, or
  94 *	    -ESRCH  - when the process isn't running
  95 *	    -EAGAIN - when the process moved away
  96 */
  97static int
  98task_function_call(struct task_struct *p, remote_function_f func, void *info)
  99{
 100	struct remote_function_call data = {
 101		.p	= p,
 102		.func	= func,
 103		.info	= info,
 104		.ret	= -EAGAIN,
 105	};
 106	int ret;
 107
 108	do {
 109		ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
 110		if (!ret)
 111			ret = data.ret;
 112	} while (ret == -EAGAIN);
 113
 114	return ret;
 115}
 116
 117/**
 118 * cpu_function_call - call a function on the cpu
 119 * @func:	the function to be called
 120 * @info:	the function call argument
 121 *
 122 * Calls the function @func on the remote cpu.
 123 *
 124 * returns: @func return value or -ENXIO when the cpu is offline
 125 */
 126static int cpu_function_call(int cpu, remote_function_f func, void *info)
 127{
 128	struct remote_function_call data = {
 129		.p	= NULL,
 130		.func	= func,
 131		.info	= info,
 132		.ret	= -ENXIO, /* No such CPU */
 133	};
 134
 135	smp_call_function_single(cpu, remote_function, &data, 1);
 136
 137	return data.ret;
 138}
 139
 140static inline struct perf_cpu_context *
 141__get_cpu_context(struct perf_event_context *ctx)
 142{
 143	return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
 144}
 145
 146static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
 147			  struct perf_event_context *ctx)
 148{
 149	raw_spin_lock(&cpuctx->ctx.lock);
 150	if (ctx)
 151		raw_spin_lock(&ctx->lock);
 152}
 153
 154static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
 155			    struct perf_event_context *ctx)
 156{
 157	if (ctx)
 158		raw_spin_unlock(&ctx->lock);
 159	raw_spin_unlock(&cpuctx->ctx.lock);
 160}
 161
 162#define TASK_TOMBSTONE ((void *)-1L)
 163
 164static bool is_kernel_event(struct perf_event *event)
 165{
 166	return READ_ONCE(event->owner) == TASK_TOMBSTONE;
 167}
 168
 169/*
 170 * On task ctx scheduling...
 171 *
 172 * When !ctx->nr_events a task context will not be scheduled. This means
 173 * we can disable the scheduler hooks (for performance) without leaving
 174 * pending task ctx state.
 175 *
 176 * This however results in two special cases:
 177 *
 178 *  - removing the last event from a task ctx; this is relatively straight
 179 *    forward and is done in __perf_remove_from_context.
 180 *
 181 *  - adding the first event to a task ctx; this is tricky because we cannot
 182 *    rely on ctx->is_active and therefore cannot use event_function_call().
 183 *    See perf_install_in_context().
 184 *
 185 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
 186 */
 187
 188typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
 189			struct perf_event_context *, void *);
 190
 191struct event_function_struct {
 192	struct perf_event *event;
 193	event_f func;
 194	void *data;
 195};
 196
 197static int event_function(void *info)
 198{
 199	struct event_function_struct *efs = info;
 200	struct perf_event *event = efs->event;
 201	struct perf_event_context *ctx = event->ctx;
 202	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
 203	struct perf_event_context *task_ctx = cpuctx->task_ctx;
 204	int ret = 0;
 205
 206	WARN_ON_ONCE(!irqs_disabled());
 207
 208	perf_ctx_lock(cpuctx, task_ctx);
 209	/*
 210	 * Since we do the IPI call without holding ctx->lock things can have
 211	 * changed, double check we hit the task we set out to hit.
 212	 */
 213	if (ctx->task) {
 214		if (ctx->task != current) {
 215			ret = -ESRCH;
 216			goto unlock;
 217		}
 218
 219		/*
 220		 * We only use event_function_call() on established contexts,
 221		 * and event_function() is only ever called when active (or
 222		 * rather, we'll have bailed in task_function_call() or the
 223		 * above ctx->task != current test), therefore we must have
 224		 * ctx->is_active here.
 225		 */
 226		WARN_ON_ONCE(!ctx->is_active);
 227		/*
 228		 * And since we have ctx->is_active, cpuctx->task_ctx must
 229		 * match.
 230		 */
 231		WARN_ON_ONCE(task_ctx != ctx);
 232	} else {
 233		WARN_ON_ONCE(&cpuctx->ctx != ctx);
 234	}
 235
 236	efs->func(event, cpuctx, ctx, efs->data);
 237unlock:
 238	perf_ctx_unlock(cpuctx, task_ctx);
 239
 240	return ret;
 241}
 242
 243static void event_function_local(struct perf_event *event, event_f func, void *data)
 244{
 245	struct event_function_struct efs = {
 246		.event = event,
 247		.func = func,
 248		.data = data,
 249	};
 250
 251	int ret = event_function(&efs);
 252	WARN_ON_ONCE(ret);
 253}
 254
 255static void event_function_call(struct perf_event *event, event_f func, void *data)
 256{
 257	struct perf_event_context *ctx = event->ctx;
 258	struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
 259	struct event_function_struct efs = {
 260		.event = event,
 261		.func = func,
 262		.data = data,
 263	};
 264
 265	if (!event->parent) {
 266		/*
 267		 * If this is a !child event, we must hold ctx::mutex to
 268		 * stabilize the the event->ctx relation. See
 269		 * perf_event_ctx_lock().
 270		 */
 271		lockdep_assert_held(&ctx->mutex);
 272	}
 273
 274	if (!task) {
 275		cpu_function_call(event->cpu, event_function, &efs);
 276		return;
 277	}
 278
 279	if (task == TASK_TOMBSTONE)
 280		return;
 281
 282again:
 283	if (!task_function_call(task, event_function, &efs))
 284		return;
 285
 286	raw_spin_lock_irq(&ctx->lock);
 287	/*
 288	 * Reload the task pointer, it might have been changed by
 289	 * a concurrent perf_event_context_sched_out().
 290	 */
 291	task = ctx->task;
 292	if (task == TASK_TOMBSTONE) {
 293		raw_spin_unlock_irq(&ctx->lock);
 294		return;
 295	}
 296	if (ctx->is_active) {
 297		raw_spin_unlock_irq(&ctx->lock);
 298		goto again;
 299	}
 300	func(event, NULL, ctx, data);
 301	raw_spin_unlock_irq(&ctx->lock);
 302}
 303
 304#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
 305		       PERF_FLAG_FD_OUTPUT  |\
 306		       PERF_FLAG_PID_CGROUP |\
 307		       PERF_FLAG_FD_CLOEXEC)
 308
 309/*
 310 * branch priv levels that need permission checks
 311 */
 312#define PERF_SAMPLE_BRANCH_PERM_PLM \
 313	(PERF_SAMPLE_BRANCH_KERNEL |\
 314	 PERF_SAMPLE_BRANCH_HV)
 315
 316enum event_type_t {
 317	EVENT_FLEXIBLE = 0x1,
 318	EVENT_PINNED = 0x2,
 319	EVENT_TIME = 0x4,
 320	EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
 321};
 322
 323/*
 324 * perf_sched_events : >0 events exist
 325 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
 326 */
 327
 328static void perf_sched_delayed(struct work_struct *work);
 329DEFINE_STATIC_KEY_FALSE(perf_sched_events);
 330static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
 331static DEFINE_MUTEX(perf_sched_mutex);
 332static atomic_t perf_sched_count;
 333
 334static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
 335static DEFINE_PER_CPU(int, perf_sched_cb_usages);
 336
 337static atomic_t nr_mmap_events __read_mostly;
 338static atomic_t nr_comm_events __read_mostly;
 339static atomic_t nr_task_events __read_mostly;
 340static atomic_t nr_freq_events __read_mostly;
 341static atomic_t nr_switch_events __read_mostly;
 342
 343static LIST_HEAD(pmus);
 344static DEFINE_MUTEX(pmus_lock);
 345static struct srcu_struct pmus_srcu;
 346
 347/*
 348 * perf event paranoia level:
 349 *  -1 - not paranoid at all
 350 *   0 - disallow raw tracepoint access for unpriv
 351 *   1 - disallow cpu events for unpriv
 352 *   2 - disallow kernel profiling for unpriv
 353 */
 354int sysctl_perf_event_paranoid __read_mostly = 2;
 355
 356/* Minimum for 512 kiB + 1 user control page */
 357int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
 358
 359/*
 360 * max perf event sample rate
 361 */
 362#define DEFAULT_MAX_SAMPLE_RATE		100000
 363#define DEFAULT_SAMPLE_PERIOD_NS	(NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
 364#define DEFAULT_CPU_TIME_MAX_PERCENT	25
 365
 366int sysctl_perf_event_sample_rate __read_mostly	= DEFAULT_MAX_SAMPLE_RATE;
 367
 368static int max_samples_per_tick __read_mostly	= DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
 369static int perf_sample_period_ns __read_mostly	= DEFAULT_SAMPLE_PERIOD_NS;
 370
 371static int perf_sample_allowed_ns __read_mostly =
 372	DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
 373
 374static void update_perf_cpu_limits(void)
 375{
 376	u64 tmp = perf_sample_period_ns;
 377
 378	tmp *= sysctl_perf_cpu_time_max_percent;
 379	tmp = div_u64(tmp, 100);
 380	if (!tmp)
 381		tmp = 1;
 382
 383	WRITE_ONCE(perf_sample_allowed_ns, tmp);
 384}
 385
 386static int perf_rotate_context(struct perf_cpu_context *cpuctx);
 387
 388int perf_proc_update_handler(struct ctl_table *table, int write,
 389		void __user *buffer, size_t *lenp,
 390		loff_t *ppos)
 391{
 392	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
 393
 394	if (ret || !write)
 395		return ret;
 396
 397	max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
 398	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
 399	update_perf_cpu_limits();
 400
 401	return 0;
 402}
 403
 404int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
 405
 406int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
 407				void __user *buffer, size_t *lenp,
 408				loff_t *ppos)
 409{
 410	int ret = proc_dointvec(table, write, buffer, lenp, ppos);
 411
 412	if (ret || !write)
 413		return ret;
 414
 415	if (sysctl_perf_cpu_time_max_percent == 100 ||
 416	    sysctl_perf_cpu_time_max_percent == 0) {
 417		printk(KERN_WARNING
 418		       "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
 419		WRITE_ONCE(perf_sample_allowed_ns, 0);
 420	} else {
 421		update_perf_cpu_limits();
 422	}
 423
 424	return 0;
 425}
 426
 427/*
 428 * perf samples are done in some very critical code paths (NMIs).
 429 * If they take too much CPU time, the system can lock up and not
 430 * get any real work done.  This will drop the sample rate when
 431 * we detect that events are taking too long.
 432 */
 433#define NR_ACCUMULATED_SAMPLES 128
 434static DEFINE_PER_CPU(u64, running_sample_length);
 435
 436static u64 __report_avg;
 437static u64 __report_allowed;
 438
 439static void perf_duration_warn(struct irq_work *w)
 440{
 441	printk_ratelimited(KERN_WARNING
 442		"perf: interrupt took too long (%lld > %lld), lowering "
 443		"kernel.perf_event_max_sample_rate to %d\n",
 444		__report_avg, __report_allowed,
 445		sysctl_perf_event_sample_rate);
 446}
 447
 448static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
 449
 450void perf_sample_event_took(u64 sample_len_ns)
 451{
 452	u64 max_len = READ_ONCE(perf_sample_allowed_ns);
 453	u64 running_len;
 454	u64 avg_len;
 455	u32 max;
 456
 457	if (max_len == 0)
 458		return;
 459
 460	/* Decay the counter by 1 average sample. */
 461	running_len = __this_cpu_read(running_sample_length);
 462	running_len -= running_len/NR_ACCUMULATED_SAMPLES;
 463	running_len += sample_len_ns;
 464	__this_cpu_write(running_sample_length, running_len);
 465
 466	/*
 467	 * Note: this will be biased artifically low until we have
 468	 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
 469	 * from having to maintain a count.
 470	 */
 471	avg_len = running_len/NR_ACCUMULATED_SAMPLES;
 472	if (avg_len <= max_len)
 473		return;
 474
 475	__report_avg = avg_len;
 476	__report_allowed = max_len;
 477
 478	/*
 479	 * Compute a throttle threshold 25% below the current duration.
 480	 */
 481	avg_len += avg_len / 4;
 482	max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
 483	if (avg_len < max)
 484		max /= (u32)avg_len;
 485	else
 486		max = 1;
 487
 488	WRITE_ONCE(perf_sample_allowed_ns, avg_len);
 489	WRITE_ONCE(max_samples_per_tick, max);
 490
 491	sysctl_perf_event_sample_rate = max * HZ;
 492	perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
 493
 494	if (!irq_work_queue(&perf_duration_work)) {
 495		early_printk("perf: interrupt took too long (%lld > %lld), lowering "
 496			     "kernel.perf_event_max_sample_rate to %d\n",
 497			     __report_avg, __report_allowed,
 498			     sysctl_perf_event_sample_rate);
 499	}
 500}
 501
 502static atomic64_t perf_event_id;
 503
 504static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
 505			      enum event_type_t event_type);
 506
 507static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
 508			     enum event_type_t event_type,
 509			     struct task_struct *task);
 510
 511static void update_context_time(struct perf_event_context *ctx);
 512static u64 perf_event_time(struct perf_event *event);
 513
 514void __weak perf_event_print_debug(void)	{ }
 515
 516extern __weak const char *perf_pmu_name(void)
 517{
 518	return "pmu";
 519}
 520
 521static inline u64 perf_clock(void)
 522{
 523	return local_clock();
 524}
 525
 526static inline u64 perf_event_clock(struct perf_event *event)
 
 527{
 528	return event->clock();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 529}
 530
 531#ifdef CONFIG_CGROUP_PERF
 532
 
 
 
 
 
 
 
 
 
 
 
 
 533static inline bool
 534perf_cgroup_match(struct perf_event *event)
 535{
 536	struct perf_event_context *ctx = event->ctx;
 537	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
 538
 539	/* @event doesn't care about cgroup */
 540	if (!event->cgrp)
 541		return true;
 542
 543	/* wants specific cgroup scope but @cpuctx isn't associated with any */
 544	if (!cpuctx->cgrp)
 545		return false;
 546
 547	/*
 548	 * Cgroup scoping is recursive.  An event enabled for a cgroup is
 549	 * also enabled for all its descendant cgroups.  If @cpuctx's
 550	 * cgroup is a descendant of @event's (the test covers identity
 551	 * case), it's a match.
 552	 */
 553	return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
 554				    event->cgrp->css.cgroup);
 555}
 556
 557static inline void perf_detach_cgroup(struct perf_event *event)
 
 
 
 
 
 558{
 559	css_put(&event->cgrp->css);
 
 
 
 
 
 560	event->cgrp = NULL;
 561}
 562
 563static inline int is_cgroup_event(struct perf_event *event)
 564{
 565	return event->cgrp != NULL;
 566}
 567
 568static inline u64 perf_cgroup_event_time(struct perf_event *event)
 569{
 570	struct perf_cgroup_info *t;
 571
 572	t = per_cpu_ptr(event->cgrp->info, event->cpu);
 573	return t->time;
 574}
 575
 576static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
 577{
 578	struct perf_cgroup_info *info;
 579	u64 now;
 580
 581	now = perf_clock();
 582
 583	info = this_cpu_ptr(cgrp->info);
 584
 585	info->time += now - info->timestamp;
 586	info->timestamp = now;
 587}
 588
 589static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
 590{
 591	struct perf_cgroup *cgrp_out = cpuctx->cgrp;
 592	if (cgrp_out)
 593		__update_cgrp_time(cgrp_out);
 594}
 595
 596static inline void update_cgrp_time_from_event(struct perf_event *event)
 597{
 598	struct perf_cgroup *cgrp;
 599
 600	/*
 601	 * ensure we access cgroup data only when needed and
 602	 * when we know the cgroup is pinned (css_get)
 603	 */
 604	if (!is_cgroup_event(event))
 605		return;
 606
 607	cgrp = perf_cgroup_from_task(current, event->ctx);
 608	/*
 609	 * Do not update time when cgroup is not active
 610	 */
 611	if (cgrp == event->cgrp)
 612		__update_cgrp_time(event->cgrp);
 613}
 614
 615static inline void
 616perf_cgroup_set_timestamp(struct task_struct *task,
 617			  struct perf_event_context *ctx)
 618{
 619	struct perf_cgroup *cgrp;
 620	struct perf_cgroup_info *info;
 621
 622	/*
 623	 * ctx->lock held by caller
 624	 * ensure we do not access cgroup data
 625	 * unless we have the cgroup pinned (css_get)
 626	 */
 627	if (!task || !ctx->nr_cgroups)
 628		return;
 629
 630	cgrp = perf_cgroup_from_task(task, ctx);
 631	info = this_cpu_ptr(cgrp->info);
 632	info->timestamp = ctx->timestamp;
 633}
 634
 635#define PERF_CGROUP_SWOUT	0x1 /* cgroup switch out every event */
 636#define PERF_CGROUP_SWIN	0x2 /* cgroup switch in events based on task */
 637
 638/*
 639 * reschedule events based on the cgroup constraint of task.
 640 *
 641 * mode SWOUT : schedule out everything
 642 * mode SWIN : schedule in based on cgroup for next
 643 */
 644static void perf_cgroup_switch(struct task_struct *task, int mode)
 645{
 646	struct perf_cpu_context *cpuctx;
 647	struct pmu *pmu;
 648	unsigned long flags;
 649
 650	/*
 651	 * disable interrupts to avoid geting nr_cgroup
 652	 * changes via __perf_event_disable(). Also
 653	 * avoids preemption.
 654	 */
 655	local_irq_save(flags);
 656
 657	/*
 658	 * we reschedule only in the presence of cgroup
 659	 * constrained events.
 660	 */
 
 661
 662	list_for_each_entry_rcu(pmu, &pmus, entry) {
 663		cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
 664		if (cpuctx->unique_pmu != pmu)
 665			continue; /* ensure we process each cpuctx once */
 666
 667		/*
 668		 * perf_cgroup_events says at least one
 669		 * context on this CPU has cgroup events.
 670		 *
 671		 * ctx->nr_cgroups reports the number of cgroup
 672		 * events for a context.
 673		 */
 674		if (cpuctx->ctx.nr_cgroups > 0) {
 675			perf_ctx_lock(cpuctx, cpuctx->task_ctx);
 676			perf_pmu_disable(cpuctx->ctx.pmu);
 677
 678			if (mode & PERF_CGROUP_SWOUT) {
 679				cpu_ctx_sched_out(cpuctx, EVENT_ALL);
 680				/*
 681				 * must not be done before ctxswout due
 682				 * to event_filter_match() in event_sched_out()
 683				 */
 684				cpuctx->cgrp = NULL;
 685			}
 686
 687			if (mode & PERF_CGROUP_SWIN) {
 688				WARN_ON_ONCE(cpuctx->cgrp);
 689				/*
 690				 * set cgrp before ctxsw in to allow
 691				 * event_filter_match() to not have to pass
 692				 * task around
 693				 * we pass the cpuctx->ctx to perf_cgroup_from_task()
 694				 * because cgorup events are only per-cpu
 695				 */
 696				cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
 697				cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
 698			}
 699			perf_pmu_enable(cpuctx->ctx.pmu);
 700			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 701		}
 702	}
 703
 
 
 704	local_irq_restore(flags);
 705}
 706
 707static inline void perf_cgroup_sched_out(struct task_struct *task,
 708					 struct task_struct *next)
 709{
 710	struct perf_cgroup *cgrp1;
 711	struct perf_cgroup *cgrp2 = NULL;
 712
 713	rcu_read_lock();
 714	/*
 715	 * we come here when we know perf_cgroup_events > 0
 716	 * we do not need to pass the ctx here because we know
 717	 * we are holding the rcu lock
 718	 */
 719	cgrp1 = perf_cgroup_from_task(task, NULL);
 720	cgrp2 = perf_cgroup_from_task(next, NULL);
 
 
 
 
 
 
 721
 722	/*
 723	 * only schedule out current cgroup events if we know
 724	 * that we are switching to a different cgroup. Otherwise,
 725	 * do no touch the cgroup events.
 726	 */
 727	if (cgrp1 != cgrp2)
 728		perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
 729
 730	rcu_read_unlock();
 731}
 732
 733static inline void perf_cgroup_sched_in(struct task_struct *prev,
 734					struct task_struct *task)
 735{
 736	struct perf_cgroup *cgrp1;
 737	struct perf_cgroup *cgrp2 = NULL;
 738
 739	rcu_read_lock();
 740	/*
 741	 * we come here when we know perf_cgroup_events > 0
 742	 * we do not need to pass the ctx here because we know
 743	 * we are holding the rcu lock
 744	 */
 745	cgrp1 = perf_cgroup_from_task(task, NULL);
 746	cgrp2 = perf_cgroup_from_task(prev, NULL);
 
 
 747
 748	/*
 749	 * only need to schedule in cgroup events if we are changing
 750	 * cgroup during ctxsw. Cgroup events were not scheduled
 751	 * out of ctxsw out if that was not the case.
 752	 */
 753	if (cgrp1 != cgrp2)
 754		perf_cgroup_switch(task, PERF_CGROUP_SWIN);
 755
 756	rcu_read_unlock();
 757}
 758
 759static inline int perf_cgroup_connect(int fd, struct perf_event *event,
 760				      struct perf_event_attr *attr,
 761				      struct perf_event *group_leader)
 762{
 763	struct perf_cgroup *cgrp;
 764	struct cgroup_subsys_state *css;
 765	struct fd f = fdget(fd);
 766	int ret = 0;
 767
 768	if (!f.file)
 
 769		return -EBADF;
 770
 771	css = css_tryget_online_from_dir(f.file->f_path.dentry,
 772					 &perf_event_cgrp_subsys);
 773	if (IS_ERR(css)) {
 774		ret = PTR_ERR(css);
 775		goto out;
 776	}
 777
 778	cgrp = container_of(css, struct perf_cgroup, css);
 779	event->cgrp = cgrp;
 780
 
 
 
 781	/*
 782	 * all events in a group must monitor
 783	 * the same cgroup because a task belongs
 784	 * to only one perf cgroup at a time
 785	 */
 786	if (group_leader && group_leader->cgrp != cgrp) {
 787		perf_detach_cgroup(event);
 788		ret = -EINVAL;
 789	}
 790out:
 791	fdput(f);
 792	return ret;
 793}
 794
 795static inline void
 796perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
 797{
 798	struct perf_cgroup_info *t;
 799	t = per_cpu_ptr(event->cgrp->info, event->cpu);
 800	event->shadow_ctx_time = now - t->timestamp;
 801}
 802
 803static inline void
 804perf_cgroup_defer_enabled(struct perf_event *event)
 805{
 806	/*
 807	 * when the current task's perf cgroup does not match
 808	 * the event's, we need to remember to call the
 809	 * perf_mark_enable() function the first time a task with
 810	 * a matching perf cgroup is scheduled in.
 811	 */
 812	if (is_cgroup_event(event) && !perf_cgroup_match(event))
 813		event->cgrp_defer_enabled = 1;
 814}
 815
 816static inline void
 817perf_cgroup_mark_enabled(struct perf_event *event,
 818			 struct perf_event_context *ctx)
 819{
 820	struct perf_event *sub;
 821	u64 tstamp = perf_event_time(event);
 822
 823	if (!event->cgrp_defer_enabled)
 824		return;
 825
 826	event->cgrp_defer_enabled = 0;
 827
 828	event->tstamp_enabled = tstamp - event->total_time_enabled;
 829	list_for_each_entry(sub, &event->sibling_list, group_entry) {
 830		if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
 831			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
 832			sub->cgrp_defer_enabled = 0;
 833		}
 834	}
 835}
 836#else /* !CONFIG_CGROUP_PERF */
 837
 838static inline bool
 839perf_cgroup_match(struct perf_event *event)
 840{
 841	return true;
 842}
 843
 844static inline void perf_detach_cgroup(struct perf_event *event)
 845{}
 846
 847static inline int is_cgroup_event(struct perf_event *event)
 848{
 849	return 0;
 850}
 851
 852static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
 853{
 854	return 0;
 855}
 856
 857static inline void update_cgrp_time_from_event(struct perf_event *event)
 858{
 859}
 860
 861static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
 862{
 863}
 864
 865static inline void perf_cgroup_sched_out(struct task_struct *task,
 866					 struct task_struct *next)
 867{
 868}
 869
 870static inline void perf_cgroup_sched_in(struct task_struct *prev,
 871					struct task_struct *task)
 872{
 873}
 874
 875static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
 876				      struct perf_event_attr *attr,
 877				      struct perf_event *group_leader)
 878{
 879	return -EINVAL;
 880}
 881
 882static inline void
 883perf_cgroup_set_timestamp(struct task_struct *task,
 884			  struct perf_event_context *ctx)
 885{
 886}
 887
 888void
 889perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
 890{
 891}
 892
 893static inline void
 894perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
 895{
 896}
 897
 898static inline u64 perf_cgroup_event_time(struct perf_event *event)
 899{
 900	return 0;
 901}
 902
 903static inline void
 904perf_cgroup_defer_enabled(struct perf_event *event)
 905{
 906}
 907
 908static inline void
 909perf_cgroup_mark_enabled(struct perf_event *event,
 910			 struct perf_event_context *ctx)
 911{
 912}
 913#endif
 914
 915/*
 916 * set default to be dependent on timer tick just
 917 * like original code
 918 */
 919#define PERF_CPU_HRTIMER (1000 / HZ)
 920/*
 921 * function must be called with interrupts disbled
 922 */
 923static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
 924{
 925	struct perf_cpu_context *cpuctx;
 926	int rotations = 0;
 927
 928	WARN_ON(!irqs_disabled());
 929
 930	cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
 931	rotations = perf_rotate_context(cpuctx);
 932
 933	raw_spin_lock(&cpuctx->hrtimer_lock);
 934	if (rotations)
 935		hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
 936	else
 937		cpuctx->hrtimer_active = 0;
 938	raw_spin_unlock(&cpuctx->hrtimer_lock);
 939
 940	return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
 941}
 942
 943static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
 944{
 945	struct hrtimer *timer = &cpuctx->hrtimer;
 946	struct pmu *pmu = cpuctx->ctx.pmu;
 947	u64 interval;
 948
 949	/* no multiplexing needed for SW PMU */
 950	if (pmu->task_ctx_nr == perf_sw_context)
 951		return;
 952
 953	/*
 954	 * check default is sane, if not set then force to
 955	 * default interval (1/tick)
 956	 */
 957	interval = pmu->hrtimer_interval_ms;
 958	if (interval < 1)
 959		interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
 960
 961	cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
 962
 963	raw_spin_lock_init(&cpuctx->hrtimer_lock);
 964	hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
 965	timer->function = perf_mux_hrtimer_handler;
 966}
 967
 968static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
 969{
 970	struct hrtimer *timer = &cpuctx->hrtimer;
 971	struct pmu *pmu = cpuctx->ctx.pmu;
 972	unsigned long flags;
 973
 974	/* not for SW PMU */
 975	if (pmu->task_ctx_nr == perf_sw_context)
 976		return 0;
 977
 978	raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
 979	if (!cpuctx->hrtimer_active) {
 980		cpuctx->hrtimer_active = 1;
 981		hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
 982		hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
 983	}
 984	raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
 985
 986	return 0;
 987}
 988
 989void perf_pmu_disable(struct pmu *pmu)
 990{
 991	int *count = this_cpu_ptr(pmu->pmu_disable_count);
 992	if (!(*count)++)
 993		pmu->pmu_disable(pmu);
 994}
 995
 996void perf_pmu_enable(struct pmu *pmu)
 997{
 998	int *count = this_cpu_ptr(pmu->pmu_disable_count);
 999	if (!--(*count))
1000		pmu->pmu_enable(pmu);
1001}
1002
1003static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1004
1005/*
1006 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1007 * perf_event_task_tick() are fully serialized because they're strictly cpu
1008 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1009 * disabled, while perf_event_task_tick is called from IRQ context.
1010 */
1011static void perf_event_ctx_activate(struct perf_event_context *ctx)
1012{
1013	struct list_head *head = this_cpu_ptr(&active_ctx_list);
1014
1015	WARN_ON(!irqs_disabled());
1016
1017	WARN_ON(!list_empty(&ctx->active_ctx_list));
1018
1019	list_add(&ctx->active_ctx_list, head);
1020}
1021
1022static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1023{
1024	WARN_ON(!irqs_disabled());
1025
1026	WARN_ON(list_empty(&ctx->active_ctx_list));
1027
1028	list_del_init(&ctx->active_ctx_list);
1029}
1030
1031static void get_ctx(struct perf_event_context *ctx)
1032{
1033	WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1034}
1035
1036static void free_ctx(struct rcu_head *head)
1037{
1038	struct perf_event_context *ctx;
1039
1040	ctx = container_of(head, struct perf_event_context, rcu_head);
1041	kfree(ctx->task_ctx_data);
1042	kfree(ctx);
1043}
1044
1045static void put_ctx(struct perf_event_context *ctx)
1046{
1047	if (atomic_dec_and_test(&ctx->refcount)) {
1048		if (ctx->parent_ctx)
1049			put_ctx(ctx->parent_ctx);
1050		if (ctx->task && ctx->task != TASK_TOMBSTONE)
1051			put_task_struct(ctx->task);
1052		call_rcu(&ctx->rcu_head, free_ctx);
1053	}
1054}
1055
1056/*
1057 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1058 * perf_pmu_migrate_context() we need some magic.
1059 *
1060 * Those places that change perf_event::ctx will hold both
1061 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1062 *
1063 * Lock ordering is by mutex address. There are two other sites where
1064 * perf_event_context::mutex nests and those are:
1065 *
1066 *  - perf_event_exit_task_context()	[ child , 0 ]
1067 *      perf_event_exit_event()
1068 *        put_event()			[ parent, 1 ]
1069 *
1070 *  - perf_event_init_context()		[ parent, 0 ]
1071 *      inherit_task_group()
1072 *        inherit_group()
1073 *          inherit_event()
1074 *            perf_event_alloc()
1075 *              perf_init_event()
1076 *                perf_try_init_event()	[ child , 1 ]
1077 *
1078 * While it appears there is an obvious deadlock here -- the parent and child
1079 * nesting levels are inverted between the two. This is in fact safe because
1080 * life-time rules separate them. That is an exiting task cannot fork, and a
1081 * spawning task cannot (yet) exit.
1082 *
1083 * But remember that that these are parent<->child context relations, and
1084 * migration does not affect children, therefore these two orderings should not
1085 * interact.
1086 *
1087 * The change in perf_event::ctx does not affect children (as claimed above)
1088 * because the sys_perf_event_open() case will install a new event and break
1089 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1090 * concerned with cpuctx and that doesn't have children.
1091 *
1092 * The places that change perf_event::ctx will issue:
1093 *
1094 *   perf_remove_from_context();
1095 *   synchronize_rcu();
1096 *   perf_install_in_context();
1097 *
1098 * to affect the change. The remove_from_context() + synchronize_rcu() should
1099 * quiesce the event, after which we can install it in the new location. This
1100 * means that only external vectors (perf_fops, prctl) can perturb the event
1101 * while in transit. Therefore all such accessors should also acquire
1102 * perf_event_context::mutex to serialize against this.
1103 *
1104 * However; because event->ctx can change while we're waiting to acquire
1105 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1106 * function.
1107 *
1108 * Lock order:
1109 *    cred_guard_mutex
1110 *	task_struct::perf_event_mutex
1111 *	  perf_event_context::mutex
1112 *	    perf_event::child_mutex;
1113 *	      perf_event_context::lock
1114 *	    perf_event::mmap_mutex
1115 *	    mmap_sem
1116 */
1117static struct perf_event_context *
1118perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1119{
1120	struct perf_event_context *ctx;
1121
1122again:
1123	rcu_read_lock();
1124	ctx = ACCESS_ONCE(event->ctx);
1125	if (!atomic_inc_not_zero(&ctx->refcount)) {
1126		rcu_read_unlock();
1127		goto again;
1128	}
1129	rcu_read_unlock();
1130
1131	mutex_lock_nested(&ctx->mutex, nesting);
1132	if (event->ctx != ctx) {
1133		mutex_unlock(&ctx->mutex);
1134		put_ctx(ctx);
1135		goto again;
1136	}
1137
1138	return ctx;
1139}
1140
1141static inline struct perf_event_context *
1142perf_event_ctx_lock(struct perf_event *event)
1143{
1144	return perf_event_ctx_lock_nested(event, 0);
1145}
1146
1147static void perf_event_ctx_unlock(struct perf_event *event,
1148				  struct perf_event_context *ctx)
1149{
1150	mutex_unlock(&ctx->mutex);
1151	put_ctx(ctx);
1152}
1153
1154/*
1155 * This must be done under the ctx->lock, such as to serialize against
1156 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1157 * calling scheduler related locks and ctx->lock nests inside those.
1158 */
1159static __must_check struct perf_event_context *
1160unclone_ctx(struct perf_event_context *ctx)
1161{
1162	struct perf_event_context *parent_ctx = ctx->parent_ctx;
1163
1164	lockdep_assert_held(&ctx->lock);
1165
1166	if (parent_ctx)
1167		ctx->parent_ctx = NULL;
1168	ctx->generation++;
1169
1170	return parent_ctx;
1171}
1172
1173static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1174{
1175	/*
1176	 * only top level events have the pid namespace they were created in
1177	 */
1178	if (event->parent)
1179		event = event->parent;
1180
1181	return task_tgid_nr_ns(p, event->ns);
1182}
1183
1184static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1185{
1186	/*
1187	 * only top level events have the pid namespace they were created in
1188	 */
1189	if (event->parent)
1190		event = event->parent;
1191
1192	return task_pid_nr_ns(p, event->ns);
1193}
1194
1195/*
1196 * If we inherit events we want to return the parent event id
1197 * to userspace.
1198 */
1199static u64 primary_event_id(struct perf_event *event)
1200{
1201	u64 id = event->id;
1202
1203	if (event->parent)
1204		id = event->parent->id;
1205
1206	return id;
1207}
1208
1209/*
1210 * Get the perf_event_context for a task and lock it.
1211 *
1212 * This has to cope with with the fact that until it is locked,
1213 * the context could get moved to another task.
1214 */
1215static struct perf_event_context *
1216perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1217{
1218	struct perf_event_context *ctx;
1219
1220retry:
1221	/*
1222	 * One of the few rules of preemptible RCU is that one cannot do
1223	 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1224	 * part of the read side critical section was irqs-enabled -- see
1225	 * rcu_read_unlock_special().
1226	 *
1227	 * Since ctx->lock nests under rq->lock we must ensure the entire read
1228	 * side critical section has interrupts disabled.
1229	 */
1230	local_irq_save(*flags);
1231	rcu_read_lock();
 
1232	ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1233	if (ctx) {
1234		/*
1235		 * If this context is a clone of another, it might
1236		 * get swapped for another underneath us by
1237		 * perf_event_task_sched_out, though the
1238		 * rcu_read_lock() protects us from any context
1239		 * getting freed.  Lock the context and check if it
1240		 * got swapped before we could get the lock, and retry
1241		 * if so.  If we locked the right context, then it
1242		 * can't get swapped on us any more.
1243		 */
1244		raw_spin_lock(&ctx->lock);
1245		if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1246			raw_spin_unlock(&ctx->lock);
1247			rcu_read_unlock();
1248			local_irq_restore(*flags);
1249			goto retry;
1250		}
1251
1252		if (ctx->task == TASK_TOMBSTONE ||
1253		    !atomic_inc_not_zero(&ctx->refcount)) {
1254			raw_spin_unlock(&ctx->lock);
1255			ctx = NULL;
1256		} else {
1257			WARN_ON_ONCE(ctx->task != task);
1258		}
1259	}
1260	rcu_read_unlock();
1261	if (!ctx)
1262		local_irq_restore(*flags);
1263	return ctx;
1264}
1265
1266/*
1267 * Get the context for a task and increment its pin_count so it
1268 * can't get swapped to another task.  This also increments its
1269 * reference count so that the context can't get freed.
1270 */
1271static struct perf_event_context *
1272perf_pin_task_context(struct task_struct *task, int ctxn)
1273{
1274	struct perf_event_context *ctx;
1275	unsigned long flags;
1276
1277	ctx = perf_lock_task_context(task, ctxn, &flags);
1278	if (ctx) {
1279		++ctx->pin_count;
1280		raw_spin_unlock_irqrestore(&ctx->lock, flags);
1281	}
1282	return ctx;
1283}
1284
1285static void perf_unpin_context(struct perf_event_context *ctx)
1286{
1287	unsigned long flags;
1288
1289	raw_spin_lock_irqsave(&ctx->lock, flags);
1290	--ctx->pin_count;
1291	raw_spin_unlock_irqrestore(&ctx->lock, flags);
1292}
1293
1294/*
1295 * Update the record of the current time in a context.
1296 */
1297static void update_context_time(struct perf_event_context *ctx)
1298{
1299	u64 now = perf_clock();
1300
1301	ctx->time += now - ctx->timestamp;
1302	ctx->timestamp = now;
1303}
1304
1305static u64 perf_event_time(struct perf_event *event)
1306{
1307	struct perf_event_context *ctx = event->ctx;
1308
1309	if (is_cgroup_event(event))
1310		return perf_cgroup_event_time(event);
1311
1312	return ctx ? ctx->time : 0;
1313}
1314
1315/*
1316 * Update the total_time_enabled and total_time_running fields for a event.
 
1317 */
1318static void update_event_times(struct perf_event *event)
1319{
1320	struct perf_event_context *ctx = event->ctx;
1321	u64 run_end;
1322
1323	lockdep_assert_held(&ctx->lock);
1324
1325	if (event->state < PERF_EVENT_STATE_INACTIVE ||
1326	    event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1327		return;
1328
1329	/*
1330	 * in cgroup mode, time_enabled represents
1331	 * the time the event was enabled AND active
1332	 * tasks were in the monitored cgroup. This is
1333	 * independent of the activity of the context as
1334	 * there may be a mix of cgroup and non-cgroup events.
1335	 *
1336	 * That is why we treat cgroup events differently
1337	 * here.
1338	 */
1339	if (is_cgroup_event(event))
1340		run_end = perf_cgroup_event_time(event);
1341	else if (ctx->is_active)
1342		run_end = ctx->time;
1343	else
1344		run_end = event->tstamp_stopped;
1345
1346	event->total_time_enabled = run_end - event->tstamp_enabled;
1347
1348	if (event->state == PERF_EVENT_STATE_INACTIVE)
1349		run_end = event->tstamp_stopped;
1350	else
1351		run_end = perf_event_time(event);
1352
1353	event->total_time_running = run_end - event->tstamp_running;
1354
1355}
1356
1357/*
1358 * Update total_time_enabled and total_time_running for all events in a group.
1359 */
1360static void update_group_times(struct perf_event *leader)
1361{
1362	struct perf_event *event;
1363
1364	update_event_times(leader);
1365	list_for_each_entry(event, &leader->sibling_list, group_entry)
1366		update_event_times(event);
1367}
1368
1369static struct list_head *
1370ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1371{
1372	if (event->attr.pinned)
1373		return &ctx->pinned_groups;
1374	else
1375		return &ctx->flexible_groups;
1376}
1377
1378/*
1379 * Add a event from the lists for its context.
1380 * Must be called with ctx->mutex and ctx->lock held.
1381 */
1382static void
1383list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1384{
1385	lockdep_assert_held(&ctx->lock);
1386
1387	WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1388	event->attach_state |= PERF_ATTACH_CONTEXT;
1389
1390	/*
1391	 * If we're a stand alone event or group leader, we go to the context
1392	 * list, group events are kept attached to the group so that
1393	 * perf_group_detach can, at all times, locate all siblings.
1394	 */
1395	if (event->group_leader == event) {
1396		struct list_head *list;
1397
1398		if (is_software_event(event))
1399			event->group_flags |= PERF_GROUP_SOFTWARE;
1400
1401		list = ctx_group_list(event, ctx);
1402		list_add_tail(&event->group_entry, list);
1403	}
1404
1405	if (is_cgroup_event(event))
1406		ctx->nr_cgroups++;
1407
1408	list_add_rcu(&event->event_entry, &ctx->event_list);
 
 
1409	ctx->nr_events++;
1410	if (event->attr.inherit_stat)
1411		ctx->nr_stat++;
1412
1413	ctx->generation++;
1414}
1415
1416/*
1417 * Initialize event state based on the perf_event_attr::disabled.
 
1418 */
1419static inline void perf_event__state_init(struct perf_event *event)
1420{
1421	event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1422					      PERF_EVENT_STATE_INACTIVE;
1423}
1424
1425static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1426{
1427	int entry = sizeof(u64); /* value */
1428	int size = 0;
1429	int nr = 1;
1430
1431	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1432		size += sizeof(u64);
1433
1434	if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1435		size += sizeof(u64);
1436
1437	if (event->attr.read_format & PERF_FORMAT_ID)
1438		entry += sizeof(u64);
1439
1440	if (event->attr.read_format & PERF_FORMAT_GROUP) {
1441		nr += nr_siblings;
1442		size += sizeof(u64);
1443	}
1444
1445	size += entry * nr;
1446	event->read_size = size;
1447}
1448
1449static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1450{
1451	struct perf_sample_data *data;
 
1452	u16 size = 0;
1453
 
 
1454	if (sample_type & PERF_SAMPLE_IP)
1455		size += sizeof(data->ip);
1456
1457	if (sample_type & PERF_SAMPLE_ADDR)
1458		size += sizeof(data->addr);
1459
1460	if (sample_type & PERF_SAMPLE_PERIOD)
1461		size += sizeof(data->period);
1462
1463	if (sample_type & PERF_SAMPLE_WEIGHT)
1464		size += sizeof(data->weight);
1465
1466	if (sample_type & PERF_SAMPLE_READ)
1467		size += event->read_size;
1468
1469	if (sample_type & PERF_SAMPLE_DATA_SRC)
1470		size += sizeof(data->data_src.val);
1471
1472	if (sample_type & PERF_SAMPLE_TRANSACTION)
1473		size += sizeof(data->txn);
1474
1475	event->header_size = size;
1476}
1477
1478/*
1479 * Called at perf_event creation and when events are attached/detached from a
1480 * group.
1481 */
1482static void perf_event__header_size(struct perf_event *event)
1483{
1484	__perf_event_read_size(event,
1485			       event->group_leader->nr_siblings);
1486	__perf_event_header_size(event, event->attr.sample_type);
1487}
1488
1489static void perf_event__id_header_size(struct perf_event *event)
1490{
1491	struct perf_sample_data *data;
1492	u64 sample_type = event->attr.sample_type;
1493	u16 size = 0;
1494
1495	if (sample_type & PERF_SAMPLE_TID)
1496		size += sizeof(data->tid_entry);
1497
1498	if (sample_type & PERF_SAMPLE_TIME)
1499		size += sizeof(data->time);
1500
1501	if (sample_type & PERF_SAMPLE_IDENTIFIER)
1502		size += sizeof(data->id);
1503
1504	if (sample_type & PERF_SAMPLE_ID)
1505		size += sizeof(data->id);
1506
1507	if (sample_type & PERF_SAMPLE_STREAM_ID)
1508		size += sizeof(data->stream_id);
1509
1510	if (sample_type & PERF_SAMPLE_CPU)
1511		size += sizeof(data->cpu_entry);
1512
1513	event->id_header_size = size;
1514}
1515
1516static bool perf_event_validate_size(struct perf_event *event)
1517{
1518	/*
1519	 * The values computed here will be over-written when we actually
1520	 * attach the event.
1521	 */
1522	__perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1523	__perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1524	perf_event__id_header_size(event);
1525
1526	/*
1527	 * Sum the lot; should not exceed the 64k limit we have on records.
1528	 * Conservative limit to allow for callchains and other variable fields.
1529	 */
1530	if (event->read_size + event->header_size +
1531	    event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1532		return false;
1533
1534	return true;
1535}
1536
1537static void perf_group_attach(struct perf_event *event)
1538{
1539	struct perf_event *group_leader = event->group_leader, *pos;
1540
1541	/*
1542	 * We can have double attach due to group movement in perf_event_open.
1543	 */
1544	if (event->attach_state & PERF_ATTACH_GROUP)
1545		return;
1546
1547	event->attach_state |= PERF_ATTACH_GROUP;
1548
1549	if (group_leader == event)
1550		return;
1551
1552	WARN_ON_ONCE(group_leader->ctx != event->ctx);
1553
1554	if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1555			!is_software_event(event))
1556		group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1557
1558	list_add_tail(&event->group_entry, &group_leader->sibling_list);
1559	group_leader->nr_siblings++;
1560
1561	perf_event__header_size(group_leader);
1562
1563	list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1564		perf_event__header_size(pos);
1565}
1566
1567/*
1568 * Remove a event from the lists for its context.
1569 * Must be called with ctx->mutex and ctx->lock held.
1570 */
1571static void
1572list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1573{
1574	struct perf_cpu_context *cpuctx;
1575
1576	WARN_ON_ONCE(event->ctx != ctx);
1577	lockdep_assert_held(&ctx->lock);
1578
1579	/*
1580	 * We can have double detach due to exit/hot-unplug + close.
1581	 */
1582	if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1583		return;
1584
1585	event->attach_state &= ~PERF_ATTACH_CONTEXT;
1586
1587	if (is_cgroup_event(event)) {
1588		ctx->nr_cgroups--;
1589		/*
1590		 * Because cgroup events are always per-cpu events, this will
1591		 * always be called from the right CPU.
1592		 */
1593		cpuctx = __get_cpu_context(ctx);
1594		/*
1595		 * If there are no more cgroup events then clear cgrp to avoid
1596		 * stale pointer in update_cgrp_time_from_cpuctx().
 
1597		 */
1598		if (!ctx->nr_cgroups)
1599			cpuctx->cgrp = NULL;
1600	}
1601
1602	ctx->nr_events--;
1603	if (event->attr.inherit_stat)
1604		ctx->nr_stat--;
1605
1606	list_del_rcu(&event->event_entry);
1607
1608	if (event->group_leader == event)
1609		list_del_init(&event->group_entry);
1610
1611	update_group_times(event);
1612
1613	/*
1614	 * If event was in error state, then keep it
1615	 * that way, otherwise bogus counts will be
1616	 * returned on read(). The only way to get out
1617	 * of error state is by explicit re-enabling
1618	 * of the event
1619	 */
1620	if (event->state > PERF_EVENT_STATE_OFF)
1621		event->state = PERF_EVENT_STATE_OFF;
1622
1623	ctx->generation++;
1624}
1625
1626static void perf_group_detach(struct perf_event *event)
1627{
1628	struct perf_event *sibling, *tmp;
1629	struct list_head *list = NULL;
1630
1631	/*
1632	 * We can have double detach due to exit/hot-unplug + close.
1633	 */
1634	if (!(event->attach_state & PERF_ATTACH_GROUP))
1635		return;
1636
1637	event->attach_state &= ~PERF_ATTACH_GROUP;
1638
1639	/*
1640	 * If this is a sibling, remove it from its group.
1641	 */
1642	if (event->group_leader != event) {
1643		list_del_init(&event->group_entry);
1644		event->group_leader->nr_siblings--;
1645		goto out;
1646	}
1647
1648	if (!list_empty(&event->group_entry))
1649		list = &event->group_entry;
1650
1651	/*
1652	 * If this was a group event with sibling events then
1653	 * upgrade the siblings to singleton events by adding them
1654	 * to whatever list we are on.
1655	 */
1656	list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1657		if (list)
1658			list_move_tail(&sibling->group_entry, list);
1659		sibling->group_leader = sibling;
1660
1661		/* Inherit group flags from the previous leader */
1662		sibling->group_flags = event->group_flags;
1663
1664		WARN_ON_ONCE(sibling->ctx != event->ctx);
1665	}
1666
1667out:
1668	perf_event__header_size(event->group_leader);
1669
1670	list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1671		perf_event__header_size(tmp);
1672}
1673
1674static bool is_orphaned_event(struct perf_event *event)
1675{
1676	return event->state == PERF_EVENT_STATE_DEAD;
1677}
1678
1679static inline int pmu_filter_match(struct perf_event *event)
1680{
1681	struct pmu *pmu = event->pmu;
1682	return pmu->filter_match ? pmu->filter_match(event) : 1;
1683}
1684
1685static inline int
1686event_filter_match(struct perf_event *event)
1687{
1688	return (event->cpu == -1 || event->cpu == smp_processor_id())
1689	    && perf_cgroup_match(event) && pmu_filter_match(event);
1690}
1691
1692static void
1693event_sched_out(struct perf_event *event,
1694		  struct perf_cpu_context *cpuctx,
1695		  struct perf_event_context *ctx)
1696{
1697	u64 tstamp = perf_event_time(event);
1698	u64 delta;
1699
1700	WARN_ON_ONCE(event->ctx != ctx);
1701	lockdep_assert_held(&ctx->lock);
1702
1703	/*
1704	 * An event which could not be activated because of
1705	 * filter mismatch still needs to have its timings
1706	 * maintained, otherwise bogus information is return
1707	 * via read() for time_enabled, time_running:
1708	 */
1709	if (event->state == PERF_EVENT_STATE_INACTIVE
1710	    && !event_filter_match(event)) {
1711		delta = tstamp - event->tstamp_stopped;
1712		event->tstamp_running += delta;
1713		event->tstamp_stopped = tstamp;
1714	}
1715
1716	if (event->state != PERF_EVENT_STATE_ACTIVE)
1717		return;
1718
1719	perf_pmu_disable(event->pmu);
1720
1721	event->tstamp_stopped = tstamp;
1722	event->pmu->del(event, 0);
1723	event->oncpu = -1;
1724	event->state = PERF_EVENT_STATE_INACTIVE;
1725	if (event->pending_disable) {
1726		event->pending_disable = 0;
1727		event->state = PERF_EVENT_STATE_OFF;
1728	}
 
 
 
1729
1730	if (!is_software_event(event))
1731		cpuctx->active_oncpu--;
1732	if (!--ctx->nr_active)
1733		perf_event_ctx_deactivate(ctx);
1734	if (event->attr.freq && event->attr.sample_freq)
1735		ctx->nr_freq--;
1736	if (event->attr.exclusive || !cpuctx->active_oncpu)
1737		cpuctx->exclusive = 0;
1738
1739	perf_pmu_enable(event->pmu);
1740}
1741
1742static void
1743group_sched_out(struct perf_event *group_event,
1744		struct perf_cpu_context *cpuctx,
1745		struct perf_event_context *ctx)
1746{
1747	struct perf_event *event;
1748	int state = group_event->state;
1749
1750	event_sched_out(group_event, cpuctx, ctx);
1751
1752	/*
1753	 * Schedule out siblings (if any):
1754	 */
1755	list_for_each_entry(event, &group_event->sibling_list, group_entry)
1756		event_sched_out(event, cpuctx, ctx);
1757
1758	if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1759		cpuctx->exclusive = 0;
1760}
1761
1762#define DETACH_GROUP	0x01UL
1763
1764/*
1765 * Cross CPU call to remove a performance event
1766 *
1767 * We disable the event on the hardware level first. After that we
1768 * remove it from the context list.
1769 */
1770static void
1771__perf_remove_from_context(struct perf_event *event,
1772			   struct perf_cpu_context *cpuctx,
1773			   struct perf_event_context *ctx,
1774			   void *info)
1775{
1776	unsigned long flags = (unsigned long)info;
 
 
1777
 
1778	event_sched_out(event, cpuctx, ctx);
1779	if (flags & DETACH_GROUP)
1780		perf_group_detach(event);
1781	list_del_event(event, ctx);
1782
1783	if (!ctx->nr_events && ctx->is_active) {
1784		ctx->is_active = 0;
1785		if (ctx->task) {
1786			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1787			cpuctx->task_ctx = NULL;
1788		}
1789	}
 
 
 
1790}
1791
 
1792/*
1793 * Remove the event from a task's (or a CPU's) list of events.
1794 *
 
 
 
1795 * If event->ctx is a cloned context, callers must make sure that
1796 * every task struct that event->ctx->task could possibly point to
1797 * remains valid.  This is OK when called from perf_release since
1798 * that only calls us on the top-level context, which can't be a clone.
1799 * When called from perf_event_exit_task, it's OK because the
1800 * context has been detached from its task.
1801 */
1802static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1803{
1804	lockdep_assert_held(&event->ctx->mutex);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1805
1806	event_function_call(event, __perf_remove_from_context, (void *)flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1807}
1808
1809/*
1810 * Cross CPU call to disable a performance event
1811 */
1812static void __perf_event_disable(struct perf_event *event,
1813				 struct perf_cpu_context *cpuctx,
1814				 struct perf_event_context *ctx,
1815				 void *info)
1816{
1817	if (event->state < PERF_EVENT_STATE_INACTIVE)
1818		return;
 
1819
1820	update_context_time(ctx);
1821	update_cgrp_time_from_event(event);
1822	update_group_times(event);
1823	if (event == event->group_leader)
1824		group_sched_out(event, cpuctx, ctx);
1825	else
1826		event_sched_out(event, cpuctx, ctx);
1827	event->state = PERF_EVENT_STATE_OFF;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1828}
1829
1830/*
1831 * Disable a event.
1832 *
1833 * If event->ctx is a cloned context, callers must make sure that
1834 * every task struct that event->ctx->task could possibly point to
1835 * remains valid.  This condition is satisifed when called through
1836 * perf_event_for_each_child or perf_event_for_each because they
1837 * hold the top-level event's child_mutex, so any descendant that
1838 * goes to exit will block in perf_event_exit_event().
1839 *
1840 * When called from perf_pending_event it's OK because event->ctx
1841 * is the current context on this CPU and preemption is disabled,
1842 * hence we can't get into perf_event_task_sched_out for this context.
1843 */
1844static void _perf_event_disable(struct perf_event *event)
1845{
1846	struct perf_event_context *ctx = event->ctx;
 
1847
1848	raw_spin_lock_irq(&ctx->lock);
1849	if (event->state <= PERF_EVENT_STATE_OFF) {
1850		raw_spin_unlock_irq(&ctx->lock);
 
 
1851		return;
1852	}
1853	raw_spin_unlock_irq(&ctx->lock);
1854
1855	event_function_call(event, __perf_event_disable, NULL);
1856}
1857
1858void perf_event_disable_local(struct perf_event *event)
1859{
1860	event_function_local(event, __perf_event_disable, NULL);
1861}
1862
1863/*
1864 * Strictly speaking kernel users cannot create groups and therefore this
1865 * interface does not need the perf_event_ctx_lock() magic.
1866 */
1867void perf_event_disable(struct perf_event *event)
1868{
1869	struct perf_event_context *ctx;
 
 
 
 
 
 
1870
1871	ctx = perf_event_ctx_lock(event);
1872	_perf_event_disable(event);
1873	perf_event_ctx_unlock(event, ctx);
 
 
 
 
 
 
1874}
1875EXPORT_SYMBOL_GPL(perf_event_disable);
1876
1877static void perf_set_shadow_time(struct perf_event *event,
1878				 struct perf_event_context *ctx,
1879				 u64 tstamp)
1880{
1881	/*
1882	 * use the correct time source for the time snapshot
1883	 *
1884	 * We could get by without this by leveraging the
1885	 * fact that to get to this function, the caller
1886	 * has most likely already called update_context_time()
1887	 * and update_cgrp_time_xx() and thus both timestamp
1888	 * are identical (or very close). Given that tstamp is,
1889	 * already adjusted for cgroup, we could say that:
1890	 *    tstamp - ctx->timestamp
1891	 * is equivalent to
1892	 *    tstamp - cgrp->timestamp.
1893	 *
1894	 * Then, in perf_output_read(), the calculation would
1895	 * work with no changes because:
1896	 * - event is guaranteed scheduled in
1897	 * - no scheduled out in between
1898	 * - thus the timestamp would be the same
1899	 *
1900	 * But this is a bit hairy.
1901	 *
1902	 * So instead, we have an explicit cgroup call to remain
1903	 * within the time time source all along. We believe it
1904	 * is cleaner and simpler to understand.
1905	 */
1906	if (is_cgroup_event(event))
1907		perf_cgroup_set_shadow_time(event, tstamp);
1908	else
1909		event->shadow_ctx_time = tstamp - ctx->timestamp;
1910}
1911
1912#define MAX_INTERRUPTS (~0ULL)
1913
1914static void perf_log_throttle(struct perf_event *event, int enable);
1915static void perf_log_itrace_start(struct perf_event *event);
1916
1917static int
1918event_sched_in(struct perf_event *event,
1919		 struct perf_cpu_context *cpuctx,
1920		 struct perf_event_context *ctx)
1921{
1922	u64 tstamp = perf_event_time(event);
1923	int ret = 0;
1924
1925	lockdep_assert_held(&ctx->lock);
1926
1927	if (event->state <= PERF_EVENT_STATE_OFF)
1928		return 0;
1929
1930	event->state = PERF_EVENT_STATE_ACTIVE;
1931	event->oncpu = smp_processor_id();
1932
1933	/*
1934	 * Unthrottle events, since we scheduled we might have missed several
1935	 * ticks already, also for a heavily scheduling task there is little
1936	 * guarantee it'll get a tick in a timely manner.
1937	 */
1938	if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1939		perf_log_throttle(event, 1);
1940		event->hw.interrupts = 0;
1941	}
1942
1943	/*
1944	 * The new state must be visible before we turn it on in the hardware:
1945	 */
1946	smp_wmb();
1947
1948	perf_pmu_disable(event->pmu);
1949
1950	perf_set_shadow_time(event, ctx, tstamp);
1951
1952	perf_log_itrace_start(event);
1953
1954	if (event->pmu->add(event, PERF_EF_START)) {
1955		event->state = PERF_EVENT_STATE_INACTIVE;
1956		event->oncpu = -1;
1957		ret = -EAGAIN;
1958		goto out;
1959	}
1960
1961	event->tstamp_running += tstamp - event->tstamp_stopped;
1962
 
 
1963	if (!is_software_event(event))
1964		cpuctx->active_oncpu++;
1965	if (!ctx->nr_active++)
1966		perf_event_ctx_activate(ctx);
1967	if (event->attr.freq && event->attr.sample_freq)
1968		ctx->nr_freq++;
1969
1970	if (event->attr.exclusive)
1971		cpuctx->exclusive = 1;
1972
1973out:
1974	perf_pmu_enable(event->pmu);
1975
1976	return ret;
1977}
1978
1979static int
1980group_sched_in(struct perf_event *group_event,
1981	       struct perf_cpu_context *cpuctx,
1982	       struct perf_event_context *ctx)
1983{
1984	struct perf_event *event, *partial_group = NULL;
1985	struct pmu *pmu = ctx->pmu;
1986	u64 now = ctx->time;
1987	bool simulate = false;
1988
1989	if (group_event->state == PERF_EVENT_STATE_OFF)
1990		return 0;
1991
1992	pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1993
1994	if (event_sched_in(group_event, cpuctx, ctx)) {
1995		pmu->cancel_txn(pmu);
1996		perf_mux_hrtimer_restart(cpuctx);
1997		return -EAGAIN;
1998	}
1999
2000	/*
2001	 * Schedule in siblings as one group (if any):
2002	 */
2003	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2004		if (event_sched_in(event, cpuctx, ctx)) {
2005			partial_group = event;
2006			goto group_error;
2007		}
2008	}
2009
2010	if (!pmu->commit_txn(pmu))
2011		return 0;
2012
2013group_error:
2014	/*
2015	 * Groups can be scheduled in as one unit only, so undo any
2016	 * partial group before returning:
2017	 * The events up to the failed event are scheduled out normally,
2018	 * tstamp_stopped will be updated.
2019	 *
2020	 * The failed events and the remaining siblings need to have
2021	 * their timings updated as if they had gone thru event_sched_in()
2022	 * and event_sched_out(). This is required to get consistent timings
2023	 * across the group. This also takes care of the case where the group
2024	 * could never be scheduled by ensuring tstamp_stopped is set to mark
2025	 * the time the event was actually stopped, such that time delta
2026	 * calculation in update_event_times() is correct.
2027	 */
2028	list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2029		if (event == partial_group)
2030			simulate = true;
2031
2032		if (simulate) {
2033			event->tstamp_running += now - event->tstamp_stopped;
2034			event->tstamp_stopped = now;
2035		} else {
2036			event_sched_out(event, cpuctx, ctx);
2037		}
2038	}
2039	event_sched_out(group_event, cpuctx, ctx);
2040
2041	pmu->cancel_txn(pmu);
2042
2043	perf_mux_hrtimer_restart(cpuctx);
2044
2045	return -EAGAIN;
2046}
2047
2048/*
2049 * Work out whether we can put this event group on the CPU now.
2050 */
2051static int group_can_go_on(struct perf_event *event,
2052			   struct perf_cpu_context *cpuctx,
2053			   int can_add_hw)
2054{
2055	/*
2056	 * Groups consisting entirely of software events can always go on.
2057	 */
2058	if (event->group_flags & PERF_GROUP_SOFTWARE)
2059		return 1;
2060	/*
2061	 * If an exclusive group is already on, no other hardware
2062	 * events can go on.
2063	 */
2064	if (cpuctx->exclusive)
2065		return 0;
2066	/*
2067	 * If this group is exclusive and there are already
2068	 * events on the CPU, it can't go on.
2069	 */
2070	if (event->attr.exclusive && cpuctx->active_oncpu)
2071		return 0;
2072	/*
2073	 * Otherwise, try to add it if all previous groups were able
2074	 * to go on.
2075	 */
2076	return can_add_hw;
2077}
2078
2079static void add_event_to_ctx(struct perf_event *event,
2080			       struct perf_event_context *ctx)
2081{
2082	u64 tstamp = perf_event_time(event);
2083
2084	list_add_event(event, ctx);
2085	perf_group_attach(event);
2086	event->tstamp_enabled = tstamp;
2087	event->tstamp_running = tstamp;
2088	event->tstamp_stopped = tstamp;
2089}
2090
2091static void ctx_sched_out(struct perf_event_context *ctx,
2092			  struct perf_cpu_context *cpuctx,
2093			  enum event_type_t event_type);
2094static void
2095ctx_sched_in(struct perf_event_context *ctx,
2096	     struct perf_cpu_context *cpuctx,
2097	     enum event_type_t event_type,
2098	     struct task_struct *task);
2099
2100static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2101			       struct perf_event_context *ctx)
2102{
2103	if (!cpuctx->task_ctx)
2104		return;
2105
2106	if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2107		return;
2108
2109	ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2110}
2111
2112static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2113				struct perf_event_context *ctx,
2114				struct task_struct *task)
2115{
2116	cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2117	if (ctx)
2118		ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2119	cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2120	if (ctx)
2121		ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2122}
2123
2124static void ctx_resched(struct perf_cpu_context *cpuctx,
2125			struct perf_event_context *task_ctx)
2126{
2127	perf_pmu_disable(cpuctx->ctx.pmu);
2128	if (task_ctx)
2129		task_ctx_sched_out(cpuctx, task_ctx);
2130	cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2131	perf_event_sched_in(cpuctx, task_ctx, current);
2132	perf_pmu_enable(cpuctx->ctx.pmu);
2133}
2134
2135/*
2136 * Cross CPU call to install and enable a performance event
2137 *
2138 * Very similar to remote_function() + event_function() but cannot assume that
2139 * things like ctx->is_active and cpuctx->task_ctx are set.
2140 */
2141static int  __perf_install_in_context(void *info)
2142{
2143	struct perf_event *event = info;
2144	struct perf_event_context *ctx = event->ctx;
2145	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2146	struct perf_event_context *task_ctx = cpuctx->task_ctx;
2147	bool activate = true;
2148	int ret = 0;
2149
2150	raw_spin_lock(&cpuctx->ctx.lock);
2151	if (ctx->task) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2152		raw_spin_lock(&ctx->lock);
2153		task_ctx = ctx;
 
2154
2155		/* If we're on the wrong CPU, try again */
2156		if (task_cpu(ctx->task) != smp_processor_id()) {
2157			ret = -ESRCH;
2158			goto unlock;
2159		}
2160
2161		/*
2162		 * If we're on the right CPU, see if the task we target is
2163		 * current, if not we don't have to activate the ctx, a future
2164		 * context switch will do that for us.
2165		 */
2166		if (ctx->task != current)
2167			activate = false;
2168		else
2169			WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2170
2171	} else if (task_ctx) {
2172		raw_spin_lock(&task_ctx->lock);
2173	}
 
 
 
 
2174
2175	if (activate) {
2176		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2177		add_event_to_ctx(event, ctx);
2178		ctx_resched(cpuctx, task_ctx);
2179	} else {
2180		add_event_to_ctx(event, ctx);
2181	}
2182
2183unlock:
 
 
 
 
 
2184	perf_ctx_unlock(cpuctx, task_ctx);
2185
2186	return ret;
2187}
2188
2189/*
2190 * Attach a performance event to a context.
2191 *
2192 * Very similar to event_function_call, see comment there.
 
 
 
 
 
2193 */
2194static void
2195perf_install_in_context(struct perf_event_context *ctx,
2196			struct perf_event *event,
2197			int cpu)
2198{
2199	struct task_struct *task = READ_ONCE(ctx->task);
2200
2201	lockdep_assert_held(&ctx->mutex);
2202
2203	event->ctx = ctx;
2204	if (event->cpu != -1)
2205		event->cpu = cpu;
2206
2207	if (!task) {
 
 
 
 
2208		cpu_function_call(cpu, __perf_install_in_context, event);
2209		return;
2210	}
2211
2212	/*
2213	 * Should not happen, we validate the ctx is still alive before calling.
2214	 */
2215	if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2216		return;
2217
 
2218	/*
2219	 * Installing events is tricky because we cannot rely on ctx->is_active
2220	 * to be set in case this is the nr_events 0 -> 1 transition.
2221	 */
2222again:
2223	/*
2224	 * Cannot use task_function_call() because we need to run on the task's
2225	 * CPU regardless of whether its current or not.
2226	 */
2227	if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2228		return;
2229
2230	raw_spin_lock_irq(&ctx->lock);
2231	task = ctx->task;
2232	if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2233		/*
2234		 * Cannot happen because we already checked above (which also
2235		 * cannot happen), and we hold ctx->mutex, which serializes us
2236		 * against perf_event_exit_task_context().
2237		 */
2238		raw_spin_unlock_irq(&ctx->lock);
2239		return;
2240	}
2241	raw_spin_unlock_irq(&ctx->lock);
2242	/*
2243	 * Since !ctx->is_active doesn't mean anything, we must IPI
2244	 * unconditionally.
2245	 */
2246	goto again;
 
2247}
2248
2249/*
2250 * Put a event into inactive state and update time fields.
2251 * Enabling the leader of a group effectively enables all
2252 * the group members that aren't explicitly disabled, so we
2253 * have to update their ->tstamp_enabled also.
2254 * Note: this works for group members as well as group leaders
2255 * since the non-leader members' sibling_lists will be empty.
2256 */
2257static void __perf_event_mark_enabled(struct perf_event *event)
 
2258{
2259	struct perf_event *sub;
2260	u64 tstamp = perf_event_time(event);
2261
2262	event->state = PERF_EVENT_STATE_INACTIVE;
2263	event->tstamp_enabled = tstamp - event->total_time_enabled;
2264	list_for_each_entry(sub, &event->sibling_list, group_entry) {
2265		if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2266			sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2267	}
2268}
2269
2270/*
2271 * Cross CPU call to enable a performance event
2272 */
2273static void __perf_event_enable(struct perf_event *event,
2274				struct perf_cpu_context *cpuctx,
2275				struct perf_event_context *ctx,
2276				void *info)
2277{
 
 
2278	struct perf_event *leader = event->group_leader;
2279	struct perf_event_context *task_ctx;
 
2280
2281	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2282	    event->state <= PERF_EVENT_STATE_ERROR)
2283		return;
 
 
2284
2285	if (ctx->is_active)
2286		ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2287
2288	__perf_event_mark_enabled(event);
 
 
 
2289
2290	if (!ctx->is_active)
2291		return;
2292
2293	if (!event_filter_match(event)) {
2294		if (is_cgroup_event(event))
2295			perf_cgroup_defer_enabled(event);
2296		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2297		return;
2298	}
2299
2300	/*
2301	 * If the event is in a group and isn't the group leader,
2302	 * then don't put it on unless the group is on.
2303	 */
2304	if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2305		ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2306		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2307	}
2308
2309	task_ctx = cpuctx->task_ctx;
2310	if (ctx->task)
2311		WARN_ON_ONCE(task_ctx != ctx);
2312
2313	ctx_resched(cpuctx, task_ctx);
2314}
2315
2316/*
2317 * Enable a event.
2318 *
2319 * If event->ctx is a cloned context, callers must make sure that
2320 * every task struct that event->ctx->task could possibly point to
2321 * remains valid.  This condition is satisfied when called through
2322 * perf_event_for_each_child or perf_event_for_each as described
2323 * for perf_event_disable.
2324 */
2325static void _perf_event_enable(struct perf_event *event)
2326{
2327	struct perf_event_context *ctx = event->ctx;
 
2328
2329	raw_spin_lock_irq(&ctx->lock);
2330	if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2331	    event->state <  PERF_EVENT_STATE_ERROR) {
2332		raw_spin_unlock_irq(&ctx->lock);
 
2333		return;
2334	}
2335
 
 
 
 
2336	/*
2337	 * If the event is in error state, clear that first.
2338	 *
2339	 * That way, if we see the event in error state below, we know that it
2340	 * has gone back into error state, as distinct from the task having
2341	 * been scheduled away before the cross-call arrived.
2342	 */
2343	if (event->state == PERF_EVENT_STATE_ERROR)
2344		event->state = PERF_EVENT_STATE_OFF;
 
 
 
 
 
 
 
2345	raw_spin_unlock_irq(&ctx->lock);
2346
2347	event_function_call(event, __perf_event_enable, NULL);
2348}
2349
2350/*
2351 * See perf_event_disable();
2352 */
2353void perf_event_enable(struct perf_event *event)
2354{
2355	struct perf_event_context *ctx;
 
 
 
 
 
 
 
 
2356
2357	ctx = perf_event_ctx_lock(event);
2358	_perf_event_enable(event);
2359	perf_event_ctx_unlock(event, ctx);
2360}
2361EXPORT_SYMBOL_GPL(perf_event_enable);
2362
2363static int _perf_event_refresh(struct perf_event *event, int refresh)
2364{
2365	/*
2366	 * not supported on inherited events
2367	 */
2368	if (event->attr.inherit || !is_sampling_event(event))
2369		return -EINVAL;
2370
2371	atomic_add(refresh, &event->event_limit);
2372	_perf_event_enable(event);
2373
2374	return 0;
2375}
2376
2377/*
2378 * See perf_event_disable()
2379 */
2380int perf_event_refresh(struct perf_event *event, int refresh)
2381{
2382	struct perf_event_context *ctx;
2383	int ret;
2384
2385	ctx = perf_event_ctx_lock(event);
2386	ret = _perf_event_refresh(event, refresh);
2387	perf_event_ctx_unlock(event, ctx);
2388
2389	return ret;
2390}
2391EXPORT_SYMBOL_GPL(perf_event_refresh);
2392
2393static void ctx_sched_out(struct perf_event_context *ctx,
2394			  struct perf_cpu_context *cpuctx,
2395			  enum event_type_t event_type)
2396{
2397	int is_active = ctx->is_active;
2398	struct perf_event *event;
2399
2400	lockdep_assert_held(&ctx->lock);
2401
2402	if (likely(!ctx->nr_events)) {
2403		/*
2404		 * See __perf_remove_from_context().
2405		 */
2406		WARN_ON_ONCE(ctx->is_active);
2407		if (ctx->task)
2408			WARN_ON_ONCE(cpuctx->task_ctx);
2409		return;
2410	}
2411
2412	ctx->is_active &= ~event_type;
2413	if (!(ctx->is_active & EVENT_ALL))
2414		ctx->is_active = 0;
2415
2416	if (ctx->task) {
2417		WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2418		if (!ctx->is_active)
2419			cpuctx->task_ctx = NULL;
2420	}
2421
2422	/*
2423	 * Always update time if it was set; not only when it changes.
2424	 * Otherwise we can 'forget' to update time for any but the last
2425	 * context we sched out. For example:
2426	 *
2427	 *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2428	 *   ctx_sched_out(.event_type = EVENT_PINNED)
2429	 *
2430	 * would only update time for the pinned events.
2431	 */
2432	if (is_active & EVENT_TIME) {
2433		/* update (and stop) ctx time */
2434		update_context_time(ctx);
2435		update_cgrp_time_from_cpuctx(cpuctx);
2436	}
2437
2438	is_active ^= ctx->is_active; /* changed bits */
2439
2440	if (!ctx->nr_active || !(is_active & EVENT_ALL))
 
 
2441		return;
2442
2443	perf_pmu_disable(ctx->pmu);
2444	if (is_active & EVENT_PINNED) {
2445		list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2446			group_sched_out(event, cpuctx, ctx);
2447	}
2448
2449	if (is_active & EVENT_FLEXIBLE) {
2450		list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2451			group_sched_out(event, cpuctx, ctx);
2452	}
2453	perf_pmu_enable(ctx->pmu);
2454}
2455
2456/*
2457 * Test whether two contexts are equivalent, i.e. whether they have both been
2458 * cloned from the same version of the same context.
2459 *
2460 * Equivalence is measured using a generation number in the context that is
2461 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2462 * and list_del_event().
 
 
 
2463 */
2464static int context_equiv(struct perf_event_context *ctx1,
2465			 struct perf_event_context *ctx2)
2466{
2467	lockdep_assert_held(&ctx1->lock);
2468	lockdep_assert_held(&ctx2->lock);
2469
2470	/* Pinning disables the swap optimization */
2471	if (ctx1->pin_count || ctx2->pin_count)
2472		return 0;
2473
2474	/* If ctx1 is the parent of ctx2 */
2475	if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2476		return 1;
2477
2478	/* If ctx2 is the parent of ctx1 */
2479	if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2480		return 1;
2481
2482	/*
2483	 * If ctx1 and ctx2 have the same parent; we flatten the parent
2484	 * hierarchy, see perf_event_init_context().
2485	 */
2486	if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2487			ctx1->parent_gen == ctx2->parent_gen)
2488		return 1;
2489
2490	/* Unmatched */
2491	return 0;
2492}
2493
2494static void __perf_event_sync_stat(struct perf_event *event,
2495				     struct perf_event *next_event)
2496{
2497	u64 value;
2498
2499	if (!event->attr.inherit_stat)
2500		return;
2501
2502	/*
2503	 * Update the event value, we cannot use perf_event_read()
2504	 * because we're in the middle of a context switch and have IRQs
2505	 * disabled, which upsets smp_call_function_single(), however
2506	 * we know the event must be on the current CPU, therefore we
2507	 * don't need to use it.
2508	 */
2509	switch (event->state) {
2510	case PERF_EVENT_STATE_ACTIVE:
2511		event->pmu->read(event);
2512		/* fall-through */
2513
2514	case PERF_EVENT_STATE_INACTIVE:
2515		update_event_times(event);
2516		break;
2517
2518	default:
2519		break;
2520	}
2521
2522	/*
2523	 * In order to keep per-task stats reliable we need to flip the event
2524	 * values when we flip the contexts.
2525	 */
2526	value = local64_read(&next_event->count);
2527	value = local64_xchg(&event->count, value);
2528	local64_set(&next_event->count, value);
2529
2530	swap(event->total_time_enabled, next_event->total_time_enabled);
2531	swap(event->total_time_running, next_event->total_time_running);
2532
2533	/*
2534	 * Since we swizzled the values, update the user visible data too.
2535	 */
2536	perf_event_update_userpage(event);
2537	perf_event_update_userpage(next_event);
2538}
2539
 
 
 
2540static void perf_event_sync_stat(struct perf_event_context *ctx,
2541				   struct perf_event_context *next_ctx)
2542{
2543	struct perf_event *event, *next_event;
2544
2545	if (!ctx->nr_stat)
2546		return;
2547
2548	update_context_time(ctx);
2549
2550	event = list_first_entry(&ctx->event_list,
2551				   struct perf_event, event_entry);
2552
2553	next_event = list_first_entry(&next_ctx->event_list,
2554					struct perf_event, event_entry);
2555
2556	while (&event->event_entry != &ctx->event_list &&
2557	       &next_event->event_entry != &next_ctx->event_list) {
2558
2559		__perf_event_sync_stat(event, next_event);
2560
2561		event = list_next_entry(event, event_entry);
2562		next_event = list_next_entry(next_event, event_entry);
2563	}
2564}
2565
2566static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2567					 struct task_struct *next)
2568{
2569	struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2570	struct perf_event_context *next_ctx;
2571	struct perf_event_context *parent, *next_parent;
2572	struct perf_cpu_context *cpuctx;
2573	int do_switch = 1;
2574
2575	if (likely(!ctx))
2576		return;
2577
2578	cpuctx = __get_cpu_context(ctx);
2579	if (!cpuctx->task_ctx)
2580		return;
2581
2582	rcu_read_lock();
2583	next_ctx = next->perf_event_ctxp[ctxn];
2584	if (!next_ctx)
2585		goto unlock;
2586
2587	parent = rcu_dereference(ctx->parent_ctx);
2588	next_parent = rcu_dereference(next_ctx->parent_ctx);
2589
2590	/* If neither context have a parent context; they cannot be clones. */
2591	if (!parent && !next_parent)
2592		goto unlock;
2593
2594	if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2595		/*
2596		 * Looks like the two contexts are clones, so we might be
2597		 * able to optimize the context switch.  We lock both
2598		 * contexts and check that they are clones under the
2599		 * lock (including re-checking that neither has been
2600		 * uncloned in the meantime).  It doesn't matter which
2601		 * order we take the locks because no other cpu could
2602		 * be trying to lock both of these tasks.
2603		 */
2604		raw_spin_lock(&ctx->lock);
2605		raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2606		if (context_equiv(ctx, next_ctx)) {
2607			WRITE_ONCE(ctx->task, next);
2608			WRITE_ONCE(next_ctx->task, task);
2609
2610			swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2611
2612			/*
2613			 * RCU_INIT_POINTER here is safe because we've not
2614			 * modified the ctx and the above modification of
2615			 * ctx->task and ctx->task_ctx_data are immaterial
2616			 * since those values are always verified under
2617			 * ctx->lock which we're now holding.
2618			 */
2619			RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2620			RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2621
 
2622			do_switch = 0;
2623
2624			perf_event_sync_stat(ctx, next_ctx);
2625		}
2626		raw_spin_unlock(&next_ctx->lock);
2627		raw_spin_unlock(&ctx->lock);
2628	}
2629unlock:
2630	rcu_read_unlock();
2631
2632	if (do_switch) {
2633		raw_spin_lock(&ctx->lock);
2634		task_ctx_sched_out(cpuctx, ctx);
 
2635		raw_spin_unlock(&ctx->lock);
2636	}
2637}
2638
2639void perf_sched_cb_dec(struct pmu *pmu)
2640{
2641	this_cpu_dec(perf_sched_cb_usages);
2642}
2643
2644void perf_sched_cb_inc(struct pmu *pmu)
2645{
2646	this_cpu_inc(perf_sched_cb_usages);
2647}
2648
2649/*
2650 * This function provides the context switch callback to the lower code
2651 * layer. It is invoked ONLY when the context switch callback is enabled.
2652 */
2653static void perf_pmu_sched_task(struct task_struct *prev,
2654				struct task_struct *next,
2655				bool sched_in)
2656{
2657	struct perf_cpu_context *cpuctx;
2658	struct pmu *pmu;
2659	unsigned long flags;
2660
2661	if (prev == next)
2662		return;
2663
2664	local_irq_save(flags);
2665
2666	rcu_read_lock();
2667
2668	list_for_each_entry_rcu(pmu, &pmus, entry) {
2669		if (pmu->sched_task) {
2670			cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2671
2672			perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2673
2674			perf_pmu_disable(pmu);
2675
2676			pmu->sched_task(cpuctx->task_ctx, sched_in);
2677
2678			perf_pmu_enable(pmu);
2679
2680			perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2681		}
2682	}
2683
2684	rcu_read_unlock();
2685
2686	local_irq_restore(flags);
2687}
2688
2689static void perf_event_switch(struct task_struct *task,
2690			      struct task_struct *next_prev, bool sched_in);
2691
2692#define for_each_task_context_nr(ctxn)					\
2693	for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2694
2695/*
2696 * Called from scheduler to remove the events of the current task,
2697 * with interrupts disabled.
2698 *
2699 * We stop each event and update the event value in event->count.
2700 *
2701 * This does not protect us against NMI, but disable()
2702 * sets the disabled bit in the control field of event _before_
2703 * accessing the event control register. If a NMI hits, then it will
2704 * not restart the event.
2705 */
2706void __perf_event_task_sched_out(struct task_struct *task,
2707				 struct task_struct *next)
2708{
2709	int ctxn;
2710
2711	if (__this_cpu_read(perf_sched_cb_usages))
2712		perf_pmu_sched_task(task, next, false);
2713
2714	if (atomic_read(&nr_switch_events))
2715		perf_event_switch(task, next, false);
2716
2717	for_each_task_context_nr(ctxn)
2718		perf_event_context_sched_out(task, ctxn, next);
2719
2720	/*
2721	 * if cgroup events exist on this CPU, then we need
2722	 * to check if we have to switch out PMU state.
2723	 * cgroup event are system-wide mode only
2724	 */
2725	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2726		perf_cgroup_sched_out(task, next);
2727}
2728
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2729/*
2730 * Called with IRQs disabled
2731 */
2732static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2733			      enum event_type_t event_type)
2734{
2735	ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2736}
2737
2738static void
2739ctx_pinned_sched_in(struct perf_event_context *ctx,
2740		    struct perf_cpu_context *cpuctx)
2741{
2742	struct perf_event *event;
2743
2744	list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2745		if (event->state <= PERF_EVENT_STATE_OFF)
2746			continue;
2747		if (!event_filter_match(event))
2748			continue;
2749
2750		/* may need to reset tstamp_enabled */
2751		if (is_cgroup_event(event))
2752			perf_cgroup_mark_enabled(event, ctx);
2753
2754		if (group_can_go_on(event, cpuctx, 1))
2755			group_sched_in(event, cpuctx, ctx);
2756
2757		/*
2758		 * If this pinned group hasn't been scheduled,
2759		 * put it in error state.
2760		 */
2761		if (event->state == PERF_EVENT_STATE_INACTIVE) {
2762			update_group_times(event);
2763			event->state = PERF_EVENT_STATE_ERROR;
2764		}
2765	}
2766}
2767
2768static void
2769ctx_flexible_sched_in(struct perf_event_context *ctx,
2770		      struct perf_cpu_context *cpuctx)
2771{
2772	struct perf_event *event;
2773	int can_add_hw = 1;
2774
2775	list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2776		/* Ignore events in OFF or ERROR state */
2777		if (event->state <= PERF_EVENT_STATE_OFF)
2778			continue;
2779		/*
2780		 * Listen to the 'cpu' scheduling filter constraint
2781		 * of events:
2782		 */
2783		if (!event_filter_match(event))
2784			continue;
2785
2786		/* may need to reset tstamp_enabled */
2787		if (is_cgroup_event(event))
2788			perf_cgroup_mark_enabled(event, ctx);
2789
2790		if (group_can_go_on(event, cpuctx, can_add_hw)) {
2791			if (group_sched_in(event, cpuctx, ctx))
2792				can_add_hw = 0;
2793		}
2794	}
2795}
2796
2797static void
2798ctx_sched_in(struct perf_event_context *ctx,
2799	     struct perf_cpu_context *cpuctx,
2800	     enum event_type_t event_type,
2801	     struct task_struct *task)
2802{
2803	int is_active = ctx->is_active;
2804	u64 now;
 
2805
2806	lockdep_assert_held(&ctx->lock);
2807
2808	if (likely(!ctx->nr_events))
2809		return;
2810
2811	ctx->is_active |= (event_type | EVENT_TIME);
2812	if (ctx->task) {
2813		if (!is_active)
2814			cpuctx->task_ctx = ctx;
2815		else
2816			WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2817	}
2818
2819	is_active ^= ctx->is_active; /* changed bits */
2820
2821	if (is_active & EVENT_TIME) {
2822		/* start ctx time */
2823		now = perf_clock();
2824		ctx->timestamp = now;
2825		perf_cgroup_set_timestamp(task, ctx);
2826	}
2827
2828	/*
2829	 * First go through the list and put on any pinned groups
2830	 * in order to give them the best chance of going on.
2831	 */
2832	if (is_active & EVENT_PINNED)
2833		ctx_pinned_sched_in(ctx, cpuctx);
2834
2835	/* Then walk through the lower prio flexible groups */
2836	if (is_active & EVENT_FLEXIBLE)
2837		ctx_flexible_sched_in(ctx, cpuctx);
2838}
2839
2840static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2841			     enum event_type_t event_type,
2842			     struct task_struct *task)
2843{
2844	struct perf_event_context *ctx = &cpuctx->ctx;
2845
2846	ctx_sched_in(ctx, cpuctx, event_type, task);
2847}
2848
2849static void perf_event_context_sched_in(struct perf_event_context *ctx,
2850					struct task_struct *task)
2851{
2852	struct perf_cpu_context *cpuctx;
2853
2854	cpuctx = __get_cpu_context(ctx);
2855	if (cpuctx->task_ctx == ctx)
2856		return;
2857
2858	perf_ctx_lock(cpuctx, ctx);
2859	perf_pmu_disable(ctx->pmu);
2860	/*
2861	 * We want to keep the following priority order:
2862	 * cpu pinned (that don't need to move), task pinned,
2863	 * cpu flexible, task flexible.
2864	 */
2865	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
 
2866	perf_event_sched_in(cpuctx, ctx, task);
 
 
 
2867	perf_pmu_enable(ctx->pmu);
2868	perf_ctx_unlock(cpuctx, ctx);
 
 
 
 
 
 
2869}
2870
2871/*
2872 * Called from scheduler to add the events of the current task
2873 * with interrupts disabled.
2874 *
2875 * We restore the event value and then enable it.
2876 *
2877 * This does not protect us against NMI, but enable()
2878 * sets the enabled bit in the control field of event _before_
2879 * accessing the event control register. If a NMI hits, then it will
2880 * keep the event running.
2881 */
2882void __perf_event_task_sched_in(struct task_struct *prev,
2883				struct task_struct *task)
2884{
2885	struct perf_event_context *ctx;
2886	int ctxn;
2887
2888	/*
2889	 * If cgroup events exist on this CPU, then we need to check if we have
2890	 * to switch in PMU state; cgroup event are system-wide mode only.
2891	 *
2892	 * Since cgroup events are CPU events, we must schedule these in before
2893	 * we schedule in the task events.
2894	 */
2895	if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2896		perf_cgroup_sched_in(prev, task);
2897
2898	for_each_task_context_nr(ctxn) {
2899		ctx = task->perf_event_ctxp[ctxn];
2900		if (likely(!ctx))
2901			continue;
2902
2903		perf_event_context_sched_in(ctx, task);
2904	}
2905
2906	if (atomic_read(&nr_switch_events))
2907		perf_event_switch(task, prev, true);
2908
2909	if (__this_cpu_read(perf_sched_cb_usages))
2910		perf_pmu_sched_task(prev, task, true);
 
2911}
2912
2913static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2914{
2915	u64 frequency = event->attr.sample_freq;
2916	u64 sec = NSEC_PER_SEC;
2917	u64 divisor, dividend;
2918
2919	int count_fls, nsec_fls, frequency_fls, sec_fls;
2920
2921	count_fls = fls64(count);
2922	nsec_fls = fls64(nsec);
2923	frequency_fls = fls64(frequency);
2924	sec_fls = 30;
2925
2926	/*
2927	 * We got @count in @nsec, with a target of sample_freq HZ
2928	 * the target period becomes:
2929	 *
2930	 *             @count * 10^9
2931	 * period = -------------------
2932	 *          @nsec * sample_freq
2933	 *
2934	 */
2935
2936	/*
2937	 * Reduce accuracy by one bit such that @a and @b converge
2938	 * to a similar magnitude.
2939	 */
2940#define REDUCE_FLS(a, b)		\
2941do {					\
2942	if (a##_fls > b##_fls) {	\
2943		a >>= 1;		\
2944		a##_fls--;		\
2945	} else {			\
2946		b >>= 1;		\
2947		b##_fls--;		\
2948	}				\
2949} while (0)
2950
2951	/*
2952	 * Reduce accuracy until either term fits in a u64, then proceed with
2953	 * the other, so that finally we can do a u64/u64 division.
2954	 */
2955	while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2956		REDUCE_FLS(nsec, frequency);
2957		REDUCE_FLS(sec, count);
2958	}
2959
2960	if (count_fls + sec_fls > 64) {
2961		divisor = nsec * frequency;
2962
2963		while (count_fls + sec_fls > 64) {
2964			REDUCE_FLS(count, sec);
2965			divisor >>= 1;
2966		}
2967
2968		dividend = count * sec;
2969	} else {
2970		dividend = count * sec;
2971
2972		while (nsec_fls + frequency_fls > 64) {
2973			REDUCE_FLS(nsec, frequency);
2974			dividend >>= 1;
2975		}
2976
2977		divisor = nsec * frequency;
2978	}
2979
2980	if (!divisor)
2981		return dividend;
2982
2983	return div64_u64(dividend, divisor);
2984}
2985
2986static DEFINE_PER_CPU(int, perf_throttled_count);
2987static DEFINE_PER_CPU(u64, perf_throttled_seq);
2988
2989static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2990{
2991	struct hw_perf_event *hwc = &event->hw;
2992	s64 period, sample_period;
2993	s64 delta;
2994
2995	period = perf_calculate_period(event, nsec, count);
2996
2997	delta = (s64)(period - hwc->sample_period);
2998	delta = (delta + 7) / 8; /* low pass filter */
2999
3000	sample_period = hwc->sample_period + delta;
3001
3002	if (!sample_period)
3003		sample_period = 1;
3004
3005	hwc->sample_period = sample_period;
3006
3007	if (local64_read(&hwc->period_left) > 8*sample_period) {
3008		if (disable)
3009			event->pmu->stop(event, PERF_EF_UPDATE);
3010
3011		local64_set(&hwc->period_left, 0);
3012
3013		if (disable)
3014			event->pmu->start(event, PERF_EF_RELOAD);
3015	}
3016}
3017
3018/*
3019 * combine freq adjustment with unthrottling to avoid two passes over the
3020 * events. At the same time, make sure, having freq events does not change
3021 * the rate of unthrottling as that would introduce bias.
3022 */
3023static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3024					   int needs_unthr)
3025{
3026	struct perf_event *event;
3027	struct hw_perf_event *hwc;
3028	u64 now, period = TICK_NSEC;
3029	s64 delta;
3030
3031	/*
3032	 * only need to iterate over all events iff:
3033	 * - context have events in frequency mode (needs freq adjust)
3034	 * - there are events to unthrottle on this cpu
3035	 */
3036	if (!(ctx->nr_freq || needs_unthr))
3037		return;
3038
3039	raw_spin_lock(&ctx->lock);
3040	perf_pmu_disable(ctx->pmu);
3041
3042	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3043		if (event->state != PERF_EVENT_STATE_ACTIVE)
3044			continue;
3045
3046		if (!event_filter_match(event))
3047			continue;
3048
3049		perf_pmu_disable(event->pmu);
3050
3051		hwc = &event->hw;
3052
3053		if (hwc->interrupts == MAX_INTERRUPTS) {
3054			hwc->interrupts = 0;
 
 
 
 
 
3055			perf_log_throttle(event, 1);
3056			event->pmu->start(event, 0);
3057		}
3058
3059		if (!event->attr.freq || !event->attr.sample_freq)
3060			goto next;
3061
3062		/*
3063		 * stop the event and update event->count
3064		 */
3065		event->pmu->stop(event, PERF_EF_UPDATE);
3066
 
3067		now = local64_read(&event->count);
3068		delta = now - hwc->freq_count_stamp;
3069		hwc->freq_count_stamp = now;
3070
3071		/*
3072		 * restart the event
3073		 * reload only if value has changed
3074		 * we have stopped the event so tell that
3075		 * to perf_adjust_period() to avoid stopping it
3076		 * twice.
3077		 */
3078		if (delta > 0)
3079			perf_adjust_period(event, period, delta, false);
3080
3081		event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3082	next:
3083		perf_pmu_enable(event->pmu);
3084	}
3085
3086	perf_pmu_enable(ctx->pmu);
3087	raw_spin_unlock(&ctx->lock);
3088}
3089
3090/*
3091 * Round-robin a context's events:
3092 */
3093static void rotate_ctx(struct perf_event_context *ctx)
3094{
3095	/*
3096	 * Rotate the first entry last of non-pinned groups. Rotation might be
3097	 * disabled by the inheritance code.
3098	 */
3099	if (!ctx->rotate_disable)
3100		list_rotate_left(&ctx->flexible_groups);
3101}
3102
3103static int perf_rotate_context(struct perf_cpu_context *cpuctx)
 
 
 
 
 
3104{
 
3105	struct perf_event_context *ctx = NULL;
3106	int rotate = 0;
3107
3108	if (cpuctx->ctx.nr_events) {
 
3109		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3110			rotate = 1;
3111	}
3112
3113	ctx = cpuctx->task_ctx;
3114	if (ctx && ctx->nr_events) {
 
3115		if (ctx->nr_events != ctx->nr_active)
3116			rotate = 1;
3117	}
3118
3119	if (!rotate)
3120		goto done;
3121
3122	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3123	perf_pmu_disable(cpuctx->ctx.pmu);
 
 
 
 
 
 
3124
3125	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3126	if (ctx)
3127		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3128
3129	rotate_ctx(&cpuctx->ctx);
3130	if (ctx)
3131		rotate_ctx(ctx);
3132
3133	perf_event_sched_in(cpuctx, ctx, current);
3134
3135	perf_pmu_enable(cpuctx->ctx.pmu);
3136	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3137done:
 
 
3138
3139	return rotate;
 
3140}
3141
3142void perf_event_task_tick(void)
3143{
3144	struct list_head *head = this_cpu_ptr(&active_ctx_list);
3145	struct perf_event_context *ctx, *tmp;
3146	int throttled;
3147
3148	WARN_ON(!irqs_disabled());
3149
3150	__this_cpu_inc(perf_throttled_seq);
3151	throttled = __this_cpu_xchg(perf_throttled_count, 0);
3152	tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3153
3154	list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3155		perf_adjust_freq_unthr_context(ctx, throttled);
3156}
3157
3158static int event_enable_on_exec(struct perf_event *event,
3159				struct perf_event_context *ctx)
3160{
3161	if (!event->attr.enable_on_exec)
3162		return 0;
3163
3164	event->attr.enable_on_exec = 0;
3165	if (event->state >= PERF_EVENT_STATE_INACTIVE)
3166		return 0;
3167
3168	__perf_event_mark_enabled(event);
3169
3170	return 1;
3171}
3172
3173/*
3174 * Enable all of a task's events that have been marked enable-on-exec.
3175 * This expects task == current.
3176 */
3177static void perf_event_enable_on_exec(int ctxn)
3178{
3179	struct perf_event_context *ctx, *clone_ctx = NULL;
3180	struct perf_cpu_context *cpuctx;
3181	struct perf_event *event;
3182	unsigned long flags;
3183	int enabled = 0;
 
3184
3185	local_irq_save(flags);
3186	ctx = current->perf_event_ctxp[ctxn];
3187	if (!ctx || !ctx->nr_events)
3188		goto out;
3189
3190	cpuctx = __get_cpu_context(ctx);
3191	perf_ctx_lock(cpuctx, ctx);
3192	ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3193	list_for_each_entry(event, &ctx->event_list, event_entry)
3194		enabled |= event_enable_on_exec(event, ctx);
3195
3196	/*
3197	 * Unclone and reschedule this context if we enabled any event.
 
 
 
 
3198	 */
3199	if (enabled) {
3200		clone_ctx = unclone_ctx(ctx);
3201		ctx_resched(cpuctx, ctx);
 
 
 
 
 
 
3202	}
3203	perf_ctx_unlock(cpuctx, ctx);
3204
3205out:
3206	local_irq_restore(flags);
 
 
 
3207
3208	if (clone_ctx)
3209		put_ctx(clone_ctx);
3210}
 
 
3211
3212void perf_event_exec(void)
3213{
3214	int ctxn;
3215
3216	rcu_read_lock();
3217	for_each_task_context_nr(ctxn)
3218		perf_event_enable_on_exec(ctxn);
3219	rcu_read_unlock();
 
 
3220}
3221
3222struct perf_read_data {
3223	struct perf_event *event;
3224	bool group;
3225	int ret;
3226};
3227
3228/*
3229 * Cross CPU call to read the hardware event
3230 */
3231static void __perf_event_read(void *info)
3232{
3233	struct perf_read_data *data = info;
3234	struct perf_event *sub, *event = data->event;
3235	struct perf_event_context *ctx = event->ctx;
3236	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3237	struct pmu *pmu = event->pmu;
3238
3239	/*
3240	 * If this is a task context, we need to check whether it is
3241	 * the current task context of this cpu.  If not it has been
3242	 * scheduled out before the smp call arrived.  In that case
3243	 * event->count would have been updated to a recent sample
3244	 * when the event was scheduled out.
3245	 */
3246	if (ctx->task && cpuctx->task_ctx != ctx)
3247		return;
3248
3249	raw_spin_lock(&ctx->lock);
3250	if (ctx->is_active) {
3251		update_context_time(ctx);
3252		update_cgrp_time_from_event(event);
3253	}
3254
3255	update_event_times(event);
3256	if (event->state != PERF_EVENT_STATE_ACTIVE)
3257		goto unlock;
3258
3259	if (!data->group) {
3260		pmu->read(event);
3261		data->ret = 0;
3262		goto unlock;
3263	}
3264
3265	pmu->start_txn(pmu, PERF_PMU_TXN_READ);
 
 
 
3266
3267	pmu->read(event);
 
 
 
 
 
 
 
 
 
 
 
3268
3269	list_for_each_entry(sub, &event->sibling_list, group_entry) {
3270		update_event_times(sub);
3271		if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3272			/*
3273			 * Use sibling's PMU rather than @event's since
3274			 * sibling could be on different (eg: software) PMU.
3275			 */
3276			sub->pmu->read(sub);
 
3277		}
 
 
3278	}
3279
3280	data->ret = pmu->commit_txn(pmu);
 
3281
3282unlock:
3283	raw_spin_unlock(&ctx->lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3284}
3285
3286static inline u64 perf_event_count(struct perf_event *event)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3287{
3288	if (event->pmu->count)
3289		return event->pmu->count(event);
3290
3291	return __perf_event_count(event);
 
 
3292}
3293
3294/*
3295 * NMI-safe method to read a local event, that is an event that
3296 * is:
3297 *   - either for the current task, or for this CPU
3298 *   - does not have inherit set, for inherited task events
3299 *     will not be local and we cannot read them atomically
3300 *   - must not have a pmu::count method
3301 */
3302u64 perf_event_read_local(struct perf_event *event)
3303{
3304	unsigned long flags;
3305	u64 val;
 
3306
3307	/*
3308	 * Disabling interrupts avoids all counter scheduling (context
3309	 * switches, timer based rotation and IPIs).
 
3310	 */
3311	local_irq_save(flags);
3312
3313	/* If this is a per-task event, it must be for current */
3314	WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3315		     event->hw.target != current);
3316
3317	/* If this is a per-CPU event, it must be for this CPU */
3318	WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3319		     event->cpu != smp_processor_id());
3320
3321	/*
3322	 * It must not be an event with inherit set, we cannot read
3323	 * all child counters from atomic context.
3324	 */
3325	WARN_ON_ONCE(event->attr.inherit);
 
3326
3327	/*
3328	 * It must not have a pmu::count method, those are not
3329	 * NMI safe.
3330	 */
3331	WARN_ON_ONCE(event->pmu->count);
3332
3333	/*
3334	 * If the event is currently on this CPU, its either a per-task event,
3335	 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3336	 * oncpu == -1).
3337	 */
3338	if (event->oncpu == smp_processor_id())
3339		event->pmu->read(event);
3340
3341	val = local64_read(&event->count);
3342	local_irq_restore(flags);
 
 
3343
3344	return val;
3345}
3346
3347static int perf_event_read(struct perf_event *event, bool group)
3348{
3349	int ret = 0;
 
3350
3351	/*
3352	 * If event is enabled and currently active on a CPU, update the
3353	 * value in the event structure:
3354	 */
3355	if (event->state == PERF_EVENT_STATE_ACTIVE) {
3356		struct perf_read_data data = {
3357			.event = event,
3358			.group = group,
3359			.ret = 0,
3360		};
3361		smp_call_function_single(event->oncpu,
3362					 __perf_event_read, &data, 1);
3363		ret = data.ret;
3364	} else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3365		struct perf_event_context *ctx = event->ctx;
3366		unsigned long flags;
3367
3368		raw_spin_lock_irqsave(&ctx->lock, flags);
3369		/*
3370		 * may read while context is not active
3371		 * (e.g., thread is blocked), in that case
3372		 * we cannot update context time
3373		 */
3374		if (ctx->is_active) {
3375			update_context_time(ctx);
3376			update_cgrp_time_from_event(event);
3377		}
3378		if (group)
3379			update_group_times(event);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3380		else
3381			update_event_times(event);
3382		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3383	}
3384
3385	return ret;
 
 
 
 
 
 
 
 
3386}
3387
3388/*
3389 * Initialize the perf_event context in a task_struct:
3390 */
3391static void __perf_event_init_context(struct perf_event_context *ctx)
3392{
3393	raw_spin_lock_init(&ctx->lock);
3394	mutex_init(&ctx->mutex);
3395	INIT_LIST_HEAD(&ctx->active_ctx_list);
3396	INIT_LIST_HEAD(&ctx->pinned_groups);
3397	INIT_LIST_HEAD(&ctx->flexible_groups);
3398	INIT_LIST_HEAD(&ctx->event_list);
3399	atomic_set(&ctx->refcount, 1);
3400}
3401
3402static struct perf_event_context *
3403alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3404{
3405	struct perf_event_context *ctx;
3406
3407	ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3408	if (!ctx)
3409		return NULL;
3410
3411	__perf_event_init_context(ctx);
3412	if (task) {
3413		ctx->task = task;
3414		get_task_struct(task);
3415	}
3416	ctx->pmu = pmu;
3417
3418	return ctx;
3419}
3420
3421static struct task_struct *
3422find_lively_task_by_vpid(pid_t vpid)
3423{
3424	struct task_struct *task;
 
3425
3426	rcu_read_lock();
3427	if (!vpid)
3428		task = current;
3429	else
3430		task = find_task_by_vpid(vpid);
3431	if (task)
3432		get_task_struct(task);
3433	rcu_read_unlock();
3434
3435	if (!task)
3436		return ERR_PTR(-ESRCH);
3437
 
 
 
 
 
3438	return task;
 
 
 
 
3439}
3440
3441/*
3442 * Returns a matching context with refcount and pincount.
3443 */
3444static struct perf_event_context *
3445find_get_context(struct pmu *pmu, struct task_struct *task,
3446		struct perf_event *event)
3447{
3448	struct perf_event_context *ctx, *clone_ctx = NULL;
3449	struct perf_cpu_context *cpuctx;
3450	void *task_ctx_data = NULL;
3451	unsigned long flags;
3452	int ctxn, err;
3453	int cpu = event->cpu;
3454
3455	if (!task) {
3456		/* Must be root to operate on a CPU event: */
3457		if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3458			return ERR_PTR(-EACCES);
3459
3460		/*
3461		 * We could be clever and allow to attach a event to an
3462		 * offline CPU and activate it when the CPU comes up, but
3463		 * that's for later.
3464		 */
3465		if (!cpu_online(cpu))
3466			return ERR_PTR(-ENODEV);
3467
3468		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3469		ctx = &cpuctx->ctx;
3470		get_ctx(ctx);
3471		++ctx->pin_count;
3472
3473		return ctx;
3474	}
3475
3476	err = -EINVAL;
3477	ctxn = pmu->task_ctx_nr;
3478	if (ctxn < 0)
3479		goto errout;
3480
3481	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3482		task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3483		if (!task_ctx_data) {
3484			err = -ENOMEM;
3485			goto errout;
3486		}
3487	}
3488
3489retry:
3490	ctx = perf_lock_task_context(task, ctxn, &flags);
3491	if (ctx) {
3492		clone_ctx = unclone_ctx(ctx);
3493		++ctx->pin_count;
3494
3495		if (task_ctx_data && !ctx->task_ctx_data) {
3496			ctx->task_ctx_data = task_ctx_data;
3497			task_ctx_data = NULL;
3498		}
3499		raw_spin_unlock_irqrestore(&ctx->lock, flags);
3500
3501		if (clone_ctx)
3502			put_ctx(clone_ctx);
3503	} else {
3504		ctx = alloc_perf_context(pmu, task);
3505		err = -ENOMEM;
3506		if (!ctx)
3507			goto errout;
3508
3509		if (task_ctx_data) {
3510			ctx->task_ctx_data = task_ctx_data;
3511			task_ctx_data = NULL;
3512		}
3513
3514		err = 0;
3515		mutex_lock(&task->perf_event_mutex);
3516		/*
3517		 * If it has already passed perf_event_exit_task().
3518		 * we must see PF_EXITING, it takes this mutex too.
3519		 */
3520		if (task->flags & PF_EXITING)
3521			err = -ESRCH;
3522		else if (task->perf_event_ctxp[ctxn])
3523			err = -EAGAIN;
3524		else {
3525			get_ctx(ctx);
3526			++ctx->pin_count;
3527			rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3528		}
3529		mutex_unlock(&task->perf_event_mutex);
3530
3531		if (unlikely(err)) {
3532			put_ctx(ctx);
3533
3534			if (err == -EAGAIN)
3535				goto retry;
3536			goto errout;
3537		}
3538	}
3539
3540	kfree(task_ctx_data);
3541	return ctx;
3542
3543errout:
3544	kfree(task_ctx_data);
3545	return ERR_PTR(err);
3546}
3547
3548static void perf_event_free_filter(struct perf_event *event);
3549static void perf_event_free_bpf_prog(struct perf_event *event);
3550
3551static void free_event_rcu(struct rcu_head *head)
3552{
3553	struct perf_event *event;
3554
3555	event = container_of(head, struct perf_event, rcu_head);
3556	if (event->ns)
3557		put_pid_ns(event->ns);
3558	perf_event_free_filter(event);
3559	kfree(event);
3560}
3561
3562static void ring_buffer_attach(struct perf_event *event,
3563			       struct ring_buffer *rb);
3564
3565static void unaccount_event_cpu(struct perf_event *event, int cpu)
3566{
3567	if (event->parent)
3568		return;
3569
3570	if (is_cgroup_event(event))
3571		atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3572}
3573
3574#ifdef CONFIG_NO_HZ_FULL
3575static DEFINE_SPINLOCK(nr_freq_lock);
3576#endif
3577
3578static void unaccount_freq_event_nohz(void)
3579{
3580#ifdef CONFIG_NO_HZ_FULL
3581	spin_lock(&nr_freq_lock);
3582	if (atomic_dec_and_test(&nr_freq_events))
3583		tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3584	spin_unlock(&nr_freq_lock);
3585#endif
3586}
3587
3588static void unaccount_freq_event(void)
3589{
3590	if (tick_nohz_full_enabled())
3591		unaccount_freq_event_nohz();
3592	else
3593		atomic_dec(&nr_freq_events);
3594}
3595
3596static void unaccount_event(struct perf_event *event)
3597{
3598	bool dec = false;
3599
3600	if (event->parent)
3601		return;
3602
3603	if (event->attach_state & PERF_ATTACH_TASK)
3604		dec = true;
3605	if (event->attr.mmap || event->attr.mmap_data)
3606		atomic_dec(&nr_mmap_events);
3607	if (event->attr.comm)
3608		atomic_dec(&nr_comm_events);
3609	if (event->attr.task)
3610		atomic_dec(&nr_task_events);
3611	if (event->attr.freq)
3612		unaccount_freq_event();
3613	if (event->attr.context_switch) {
3614		dec = true;
3615		atomic_dec(&nr_switch_events);
3616	}
3617	if (is_cgroup_event(event))
3618		dec = true;
3619	if (has_branch_stack(event))
3620		dec = true;
3621
3622	if (dec) {
3623		if (!atomic_add_unless(&perf_sched_count, -1, 1))
3624			schedule_delayed_work(&perf_sched_work, HZ);
3625	}
3626
3627	unaccount_event_cpu(event, event->cpu);
3628}
3629
3630static void perf_sched_delayed(struct work_struct *work)
3631{
3632	mutex_lock(&perf_sched_mutex);
3633	if (atomic_dec_and_test(&perf_sched_count))
3634		static_branch_disable(&perf_sched_events);
3635	mutex_unlock(&perf_sched_mutex);
3636}
3637
3638/*
3639 * The following implement mutual exclusion of events on "exclusive" pmus
3640 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3641 * at a time, so we disallow creating events that might conflict, namely:
3642 *
3643 *  1) cpu-wide events in the presence of per-task events,
3644 *  2) per-task events in the presence of cpu-wide events,
3645 *  3) two matching events on the same context.
3646 *
3647 * The former two cases are handled in the allocation path (perf_event_alloc(),
3648 * _free_event()), the latter -- before the first perf_install_in_context().
3649 */
3650static int exclusive_event_init(struct perf_event *event)
3651{
3652	struct pmu *pmu = event->pmu;
3653
3654	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3655		return 0;
3656
3657	/*
3658	 * Prevent co-existence of per-task and cpu-wide events on the
3659	 * same exclusive pmu.
3660	 *
3661	 * Negative pmu::exclusive_cnt means there are cpu-wide
3662	 * events on this "exclusive" pmu, positive means there are
3663	 * per-task events.
3664	 *
3665	 * Since this is called in perf_event_alloc() path, event::ctx
3666	 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3667	 * to mean "per-task event", because unlike other attach states it
3668	 * never gets cleared.
3669	 */
3670	if (event->attach_state & PERF_ATTACH_TASK) {
3671		if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3672			return -EBUSY;
3673	} else {
3674		if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3675			return -EBUSY;
3676	}
3677
3678	return 0;
3679}
3680
3681static void exclusive_event_destroy(struct perf_event *event)
3682{
3683	struct pmu *pmu = event->pmu;
3684
3685	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3686		return;
3687
3688	/* see comment in exclusive_event_init() */
3689	if (event->attach_state & PERF_ATTACH_TASK)
3690		atomic_dec(&pmu->exclusive_cnt);
3691	else
3692		atomic_inc(&pmu->exclusive_cnt);
3693}
3694
3695static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3696{
3697	if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3698	    (e1->cpu == e2->cpu ||
3699	     e1->cpu == -1 ||
3700	     e2->cpu == -1))
3701		return true;
3702	return false;
3703}
3704
3705/* Called under the same ctx::mutex as perf_install_in_context() */
3706static bool exclusive_event_installable(struct perf_event *event,
3707					struct perf_event_context *ctx)
3708{
3709	struct perf_event *iter_event;
3710	struct pmu *pmu = event->pmu;
3711
3712	if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3713		return true;
3714
3715	list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3716		if (exclusive_event_match(iter_event, event))
3717			return false;
3718	}
3719
3720	return true;
3721}
3722
3723static void _free_event(struct perf_event *event)
3724{
3725	irq_work_sync(&event->pending);
3726
3727	unaccount_event(event);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3728
3729	if (event->rb) {
3730		/*
3731		 * Can happen when we close an event with re-directed output.
3732		 *
3733		 * Since we have a 0 refcount, perf_mmap_close() will skip
3734		 * over us; possibly making our ring_buffer_put() the last.
3735		 */
3736		mutex_lock(&event->mmap_mutex);
3737		ring_buffer_attach(event, NULL);
3738		mutex_unlock(&event->mmap_mutex);
3739	}
3740
3741	if (is_cgroup_event(event))
3742		perf_detach_cgroup(event);
3743
3744	if (!event->parent) {
3745		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3746			put_callchain_buffers();
3747	}
3748
3749	perf_event_free_bpf_prog(event);
3750
3751	if (event->destroy)
3752		event->destroy(event);
3753
3754	if (event->ctx)
3755		put_ctx(event->ctx);
3756
3757	if (event->pmu) {
3758		exclusive_event_destroy(event);
3759		module_put(event->pmu->module);
3760	}
3761
3762	call_rcu(&event->rcu_head, free_event_rcu);
3763}
3764
3765/*
3766 * Used to free events which have a known refcount of 1, such as in error paths
3767 * where the event isn't exposed yet and inherited events.
3768 */
3769static void free_event(struct perf_event *event)
3770{
3771	if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3772				"unexpected event refcount: %ld; ptr=%p\n",
3773				atomic_long_read(&event->refcount), event)) {
3774		/* leak to avoid use-after-free */
3775		return;
3776	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3777
3778	_free_event(event);
 
 
3779}
 
3780
3781/*
3782 * Remove user event from the owner task.
3783 */
3784static void perf_remove_from_owner(struct perf_event *event)
3785{
 
3786	struct task_struct *owner;
3787
 
 
3788	rcu_read_lock();
 
3789	/*
3790	 * Matches the smp_store_release() in perf_event_exit_task(). If we
3791	 * observe !owner it means the list deletion is complete and we can
3792	 * indeed free this event, otherwise we need to serialize on
3793	 * owner->perf_event_mutex.
3794	 */
3795	owner = lockless_dereference(event->owner);
3796	if (owner) {
3797		/*
3798		 * Since delayed_put_task_struct() also drops the last
3799		 * task reference we can safely take a new reference
3800		 * while holding the rcu_read_lock().
3801		 */
3802		get_task_struct(owner);
3803	}
3804	rcu_read_unlock();
3805
3806	if (owner) {
3807		/*
3808		 * If we're here through perf_event_exit_task() we're already
3809		 * holding ctx->mutex which would be an inversion wrt. the
3810		 * normal lock order.
3811		 *
3812		 * However we can safely take this lock because its the child
3813		 * ctx->mutex.
3814		 */
3815		mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3816
3817		/*
3818		 * We have to re-check the event->owner field, if it is cleared
3819		 * we raced with perf_event_exit_task(), acquiring the mutex
3820		 * ensured they're done, and we can proceed with freeing the
3821		 * event.
3822		 */
3823		if (event->owner) {
3824			list_del_init(&event->owner_entry);
3825			smp_store_release(&event->owner, NULL);
3826		}
3827		mutex_unlock(&owner->perf_event_mutex);
3828		put_task_struct(owner);
3829	}
3830}
3831
3832static void put_event(struct perf_event *event)
3833{
3834	if (!atomic_long_dec_and_test(&event->refcount))
3835		return;
3836
3837	_free_event(event);
3838}
3839
3840/*
3841 * Kill an event dead; while event:refcount will preserve the event
3842 * object, it will not preserve its functionality. Once the last 'user'
3843 * gives up the object, we'll destroy the thing.
3844 */
3845int perf_event_release_kernel(struct perf_event *event)
3846{
3847	struct perf_event_context *ctx = event->ctx;
3848	struct perf_event *child, *tmp;
3849
3850	/*
3851	 * If we got here through err_file: fput(event_file); we will not have
3852	 * attached to a context yet.
3853	 */
3854	if (!ctx) {
3855		WARN_ON_ONCE(event->attach_state &
3856				(PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3857		goto no_ctx;
3858	}
3859
3860	if (!is_kernel_event(event))
3861		perf_remove_from_owner(event);
3862
3863	ctx = perf_event_ctx_lock(event);
3864	WARN_ON_ONCE(ctx->parent_ctx);
3865	perf_remove_from_context(event, DETACH_GROUP);
3866
3867	raw_spin_lock_irq(&ctx->lock);
3868	/*
3869	 * Mark this even as STATE_DEAD, there is no external reference to it
3870	 * anymore.
3871	 *
3872	 * Anybody acquiring event->child_mutex after the below loop _must_
3873	 * also see this, most importantly inherit_event() which will avoid
3874	 * placing more children on the list.
3875	 *
3876	 * Thus this guarantees that we will in fact observe and kill _ALL_
3877	 * child events.
3878	 */
3879	event->state = PERF_EVENT_STATE_DEAD;
3880	raw_spin_unlock_irq(&ctx->lock);
3881
3882	perf_event_ctx_unlock(event, ctx);
3883
3884again:
3885	mutex_lock(&event->child_mutex);
3886	list_for_each_entry(child, &event->child_list, child_list) {
3887
3888		/*
3889		 * Cannot change, child events are not migrated, see the
3890		 * comment with perf_event_ctx_lock_nested().
3891		 */
3892		ctx = lockless_dereference(child->ctx);
3893		/*
3894		 * Since child_mutex nests inside ctx::mutex, we must jump
3895		 * through hoops. We start by grabbing a reference on the ctx.
3896		 *
3897		 * Since the event cannot get freed while we hold the
3898		 * child_mutex, the context must also exist and have a !0
3899		 * reference count.
3900		 */
3901		get_ctx(ctx);
3902
3903		/*
3904		 * Now that we have a ctx ref, we can drop child_mutex, and
3905		 * acquire ctx::mutex without fear of it going away. Then we
3906		 * can re-acquire child_mutex.
3907		 */
3908		mutex_unlock(&event->child_mutex);
3909		mutex_lock(&ctx->mutex);
3910		mutex_lock(&event->child_mutex);
3911
3912		/*
3913		 * Now that we hold ctx::mutex and child_mutex, revalidate our
3914		 * state, if child is still the first entry, it didn't get freed
3915		 * and we can continue doing so.
3916		 */
3917		tmp = list_first_entry_or_null(&event->child_list,
3918					       struct perf_event, child_list);
3919		if (tmp == child) {
3920			perf_remove_from_context(child, DETACH_GROUP);
3921			list_del(&child->child_list);
3922			free_event(child);
3923			/*
3924			 * This matches the refcount bump in inherit_event();
3925			 * this can't be the last reference.
3926			 */
3927			put_event(event);
3928		}
3929
3930		mutex_unlock(&event->child_mutex);
3931		mutex_unlock(&ctx->mutex);
3932		put_ctx(ctx);
3933		goto again;
3934	}
3935	mutex_unlock(&event->child_mutex);
3936
3937no_ctx:
3938	put_event(event); /* Must be the 'last' reference */
3939	return 0;
3940}
3941EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3942
3943/*
3944 * Called when the last reference to the file is gone.
3945 */
3946static int perf_release(struct inode *inode, struct file *file)
3947{
3948	perf_event_release_kernel(file->private_data);
3949	return 0;
3950}
3951
3952u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3953{
3954	struct perf_event *child;
3955	u64 total = 0;
3956
3957	*enabled = 0;
3958	*running = 0;
3959
3960	mutex_lock(&event->child_mutex);
3961
3962	(void)perf_event_read(event, false);
3963	total += perf_event_count(event);
3964
3965	*enabled += event->total_time_enabled +
3966			atomic64_read(&event->child_total_time_enabled);
3967	*running += event->total_time_running +
3968			atomic64_read(&event->child_total_time_running);
3969
3970	list_for_each_entry(child, &event->child_list, child_list) {
3971		(void)perf_event_read(child, false);
3972		total += perf_event_count(child);
3973		*enabled += child->total_time_enabled;
3974		*running += child->total_time_running;
3975	}
3976	mutex_unlock(&event->child_mutex);
3977
3978	return total;
3979}
3980EXPORT_SYMBOL_GPL(perf_event_read_value);
3981
3982static int __perf_read_group_add(struct perf_event *leader,
3983					u64 read_format, u64 *values)
3984{
3985	struct perf_event *sub;
3986	int n = 1; /* skip @nr */
3987	int ret;
3988
3989	ret = perf_event_read(leader, true);
3990	if (ret)
3991		return ret;
3992
3993	/*
3994	 * Since we co-schedule groups, {enabled,running} times of siblings
3995	 * will be identical to those of the leader, so we only publish one
3996	 * set.
3997	 */
3998	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3999		values[n++] += leader->total_time_enabled +
4000			atomic64_read(&leader->child_total_time_enabled);
4001	}
4002
4003	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4004		values[n++] += leader->total_time_running +
4005			atomic64_read(&leader->child_total_time_running);
4006	}
4007
4008	/*
4009	 * Write {count,id} tuples for every sibling.
4010	 */
4011	values[n++] += perf_event_count(leader);
 
 
4012	if (read_format & PERF_FORMAT_ID)
4013		values[n++] = primary_event_id(leader);
4014
4015	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4016		values[n++] += perf_event_count(sub);
4017		if (read_format & PERF_FORMAT_ID)
4018			values[n++] = primary_event_id(sub);
4019	}
4020
4021	return 0;
4022}
4023
4024static int perf_read_group(struct perf_event *event,
4025				   u64 read_format, char __user *buf)
4026{
4027	struct perf_event *leader = event->group_leader, *child;
4028	struct perf_event_context *ctx = leader->ctx;
4029	int ret;
4030	u64 *values;
4031
4032	lockdep_assert_held(&ctx->mutex);
 
4033
4034	values = kzalloc(event->read_size, GFP_KERNEL);
4035	if (!values)
4036		return -ENOMEM;
4037
4038	values[0] = 1 + leader->nr_siblings;
 
4039
4040	/*
4041	 * By locking the child_mutex of the leader we effectively
4042	 * lock the child list of all siblings.. XXX explain how.
4043	 */
4044	mutex_lock(&leader->child_mutex);
4045
4046	ret = __perf_read_group_add(leader, read_format, values);
4047	if (ret)
4048		goto unlock;
4049
4050	list_for_each_entry(child, &leader->child_list, child_list) {
4051		ret = __perf_read_group_add(child, read_format, values);
4052		if (ret)
4053			goto unlock;
4054	}
4055
4056	mutex_unlock(&leader->child_mutex);
4057
4058	ret = event->read_size;
4059	if (copy_to_user(buf, values, event->read_size))
4060		ret = -EFAULT;
4061	goto out;
4062
 
 
4063unlock:
4064	mutex_unlock(&leader->child_mutex);
4065out:
4066	kfree(values);
4067	return ret;
4068}
4069
4070static int perf_read_one(struct perf_event *event,
4071				 u64 read_format, char __user *buf)
4072{
4073	u64 enabled, running;
4074	u64 values[4];
4075	int n = 0;
4076
4077	values[n++] = perf_event_read_value(event, &enabled, &running);
4078	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4079		values[n++] = enabled;
4080	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4081		values[n++] = running;
4082	if (read_format & PERF_FORMAT_ID)
4083		values[n++] = primary_event_id(event);
4084
4085	if (copy_to_user(buf, values, n * sizeof(u64)))
4086		return -EFAULT;
4087
4088	return n * sizeof(u64);
4089}
4090
4091static bool is_event_hup(struct perf_event *event)
4092{
4093	bool no_children;
4094
4095	if (event->state > PERF_EVENT_STATE_EXIT)
4096		return false;
4097
4098	mutex_lock(&event->child_mutex);
4099	no_children = list_empty(&event->child_list);
4100	mutex_unlock(&event->child_mutex);
4101	return no_children;
4102}
4103
4104/*
4105 * Read the performance event - simple non blocking version for now
4106 */
4107static ssize_t
4108__perf_read(struct perf_event *event, char __user *buf, size_t count)
4109{
4110	u64 read_format = event->attr.read_format;
4111	int ret;
4112
4113	/*
4114	 * Return end-of-file for a read on a event that is in
4115	 * error state (i.e. because it was pinned but it couldn't be
4116	 * scheduled on to the CPU at some point).
4117	 */
4118	if (event->state == PERF_EVENT_STATE_ERROR)
4119		return 0;
4120
4121	if (count < event->read_size)
4122		return -ENOSPC;
4123
4124	WARN_ON_ONCE(event->ctx->parent_ctx);
4125	if (read_format & PERF_FORMAT_GROUP)
4126		ret = perf_read_group(event, read_format, buf);
4127	else
4128		ret = perf_read_one(event, read_format, buf);
4129
4130	return ret;
4131}
4132
4133static ssize_t
4134perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4135{
4136	struct perf_event *event = file->private_data;
4137	struct perf_event_context *ctx;
4138	int ret;
4139
4140	ctx = perf_event_ctx_lock(event);
4141	ret = __perf_read(event, buf, count);
4142	perf_event_ctx_unlock(event, ctx);
4143
4144	return ret;
4145}
4146
4147static unsigned int perf_poll(struct file *file, poll_table *wait)
4148{
4149	struct perf_event *event = file->private_data;
4150	struct ring_buffer *rb;
4151	unsigned int events = POLLHUP;
4152
4153	poll_wait(file, &event->waitq, wait);
4154
4155	if (is_event_hup(event))
4156		return events;
4157
4158	/*
4159	 * Pin the event->rb by taking event->mmap_mutex; otherwise
4160	 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4161	 */
4162	mutex_lock(&event->mmap_mutex);
4163	rb = event->rb;
4164	if (rb)
4165		events = atomic_xchg(&rb->poll, 0);
4166	mutex_unlock(&event->mmap_mutex);
 
 
 
4167	return events;
4168}
4169
4170static void _perf_event_reset(struct perf_event *event)
4171{
4172	(void)perf_event_read(event, false);
4173	local64_set(&event->count, 0);
4174	perf_event_update_userpage(event);
4175}
4176
4177/*
4178 * Holding the top-level event's child_mutex means that any
4179 * descendant process that has inherited this event will block
4180 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4181 * task existence requirements of perf_event_enable/disable.
4182 */
4183static void perf_event_for_each_child(struct perf_event *event,
4184					void (*func)(struct perf_event *))
4185{
4186	struct perf_event *child;
4187
4188	WARN_ON_ONCE(event->ctx->parent_ctx);
4189
4190	mutex_lock(&event->child_mutex);
4191	func(event);
4192	list_for_each_entry(child, &event->child_list, child_list)
4193		func(child);
4194	mutex_unlock(&event->child_mutex);
4195}
4196
4197static void perf_event_for_each(struct perf_event *event,
4198				  void (*func)(struct perf_event *))
4199{
4200	struct perf_event_context *ctx = event->ctx;
4201	struct perf_event *sibling;
4202
4203	lockdep_assert_held(&ctx->mutex);
4204
4205	event = event->group_leader;
4206
4207	perf_event_for_each_child(event, func);
 
4208	list_for_each_entry(sibling, &event->sibling_list, group_entry)
4209		perf_event_for_each_child(sibling, func);
4210}
4211
4212static void __perf_event_period(struct perf_event *event,
4213				struct perf_cpu_context *cpuctx,
4214				struct perf_event_context *ctx,
4215				void *info)
4216{
4217	u64 value = *((u64 *)info);
4218	bool active;
4219
4220	if (event->attr.freq) {
4221		event->attr.sample_freq = value;
4222	} else {
4223		event->attr.sample_period = value;
4224		event->hw.sample_period = value;
4225	}
4226
4227	active = (event->state == PERF_EVENT_STATE_ACTIVE);
4228	if (active) {
4229		perf_pmu_disable(ctx->pmu);
4230		/*
4231		 * We could be throttled; unthrottle now to avoid the tick
4232		 * trying to unthrottle while we already re-started the event.
4233		 */
4234		if (event->hw.interrupts == MAX_INTERRUPTS) {
4235			event->hw.interrupts = 0;
4236			perf_log_throttle(event, 1);
4237		}
4238		event->pmu->stop(event, PERF_EF_UPDATE);
4239	}
4240
4241	local64_set(&event->hw.period_left, 0);
4242
4243	if (active) {
4244		event->pmu->start(event, PERF_EF_RELOAD);
4245		perf_pmu_enable(ctx->pmu);
4246	}
4247}
4248
4249static int perf_event_period(struct perf_event *event, u64 __user *arg)
4250{
 
 
4251	u64 value;
4252
4253	if (!is_sampling_event(event))
4254		return -EINVAL;
4255
4256	if (copy_from_user(&value, arg, sizeof(value)))
4257		return -EFAULT;
4258
4259	if (!value)
4260		return -EINVAL;
4261
4262	if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4263		return -EINVAL;
 
 
 
 
4264
4265	event_function_call(event, __perf_event_period, &value);
 
 
 
 
 
 
4266
4267	return 0;
4268}
4269
4270static const struct file_operations perf_fops;
4271
4272static inline int perf_fget_light(int fd, struct fd *p)
4273{
4274	struct fd f = fdget(fd);
4275	if (!f.file)
4276		return -EBADF;
4277
4278	if (f.file->f_op != &perf_fops) {
4279		fdput(f);
4280		return -EBADF;
 
 
 
 
 
4281	}
4282	*p = f;
4283	return 0;
4284}
4285
4286static int perf_event_set_output(struct perf_event *event,
4287				 struct perf_event *output_event);
4288static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4289static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4290
4291static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4292{
 
4293	void (*func)(struct perf_event *);
4294	u32 flags = arg;
4295
4296	switch (cmd) {
4297	case PERF_EVENT_IOC_ENABLE:
4298		func = _perf_event_enable;
4299		break;
4300	case PERF_EVENT_IOC_DISABLE:
4301		func = _perf_event_disable;
4302		break;
4303	case PERF_EVENT_IOC_RESET:
4304		func = _perf_event_reset;
4305		break;
4306
4307	case PERF_EVENT_IOC_REFRESH:
4308		return _perf_event_refresh(event, arg);
4309
4310	case PERF_EVENT_IOC_PERIOD:
4311		return perf_event_period(event, (u64 __user *)arg);
4312
4313	case PERF_EVENT_IOC_ID:
4314	{
4315		u64 id = primary_event_id(event);
4316
4317		if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4318			return -EFAULT;
4319		return 0;
4320	}
4321
4322	case PERF_EVENT_IOC_SET_OUTPUT:
4323	{
 
 
4324		int ret;
 
4325		if (arg != -1) {
4326			struct perf_event *output_event;
4327			struct fd output;
4328			ret = perf_fget_light(arg, &output);
4329			if (ret)
4330				return ret;
4331			output_event = output.file->private_data;
4332			ret = perf_event_set_output(event, output_event);
4333			fdput(output);
4334		} else {
4335			ret = perf_event_set_output(event, NULL);
4336		}
 
 
 
 
 
4337		return ret;
4338	}
4339
4340	case PERF_EVENT_IOC_SET_FILTER:
4341		return perf_event_set_filter(event, (void __user *)arg);
4342
4343	case PERF_EVENT_IOC_SET_BPF:
4344		return perf_event_set_bpf_prog(event, arg);
4345
4346	default:
4347		return -ENOTTY;
4348	}
4349
4350	if (flags & PERF_IOC_FLAG_GROUP)
4351		perf_event_for_each(event, func);
4352	else
4353		perf_event_for_each_child(event, func);
4354
4355	return 0;
4356}
4357
4358static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4359{
4360	struct perf_event *event = file->private_data;
4361	struct perf_event_context *ctx;
4362	long ret;
4363
4364	ctx = perf_event_ctx_lock(event);
4365	ret = _perf_ioctl(event, cmd, arg);
4366	perf_event_ctx_unlock(event, ctx);
4367
4368	return ret;
4369}
4370
4371#ifdef CONFIG_COMPAT
4372static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4373				unsigned long arg)
4374{
4375	switch (_IOC_NR(cmd)) {
4376	case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4377	case _IOC_NR(PERF_EVENT_IOC_ID):
4378		/* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4379		if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4380			cmd &= ~IOCSIZE_MASK;
4381			cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4382		}
4383		break;
4384	}
4385	return perf_ioctl(file, cmd, arg);
4386}
4387#else
4388# define perf_compat_ioctl NULL
4389#endif
4390
4391int perf_event_task_enable(void)
4392{
4393	struct perf_event_context *ctx;
4394	struct perf_event *event;
4395
4396	mutex_lock(&current->perf_event_mutex);
4397	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
4398		ctx = perf_event_ctx_lock(event);
4399		perf_event_for_each_child(event, _perf_event_enable);
4400		perf_event_ctx_unlock(event, ctx);
4401	}
4402	mutex_unlock(&current->perf_event_mutex);
4403
4404	return 0;
4405}
4406
4407int perf_event_task_disable(void)
4408{
4409	struct perf_event_context *ctx;
4410	struct perf_event *event;
4411
4412	mutex_lock(&current->perf_event_mutex);
4413	list_for_each_entry(event, &current->perf_event_list, owner_entry) {
4414		ctx = perf_event_ctx_lock(event);
4415		perf_event_for_each_child(event, _perf_event_disable);
4416		perf_event_ctx_unlock(event, ctx);
4417	}
4418	mutex_unlock(&current->perf_event_mutex);
4419
4420	return 0;
4421}
4422
 
 
 
 
4423static int perf_event_index(struct perf_event *event)
4424{
4425	if (event->hw.state & PERF_HES_STOPPED)
4426		return 0;
4427
4428	if (event->state != PERF_EVENT_STATE_ACTIVE)
4429		return 0;
4430
4431	return event->pmu->event_idx(event);
4432}
4433
4434static void calc_timer_values(struct perf_event *event,
4435				u64 *now,
4436				u64 *enabled,
4437				u64 *running)
4438{
4439	u64 ctx_time;
4440
4441	*now = perf_clock();
4442	ctx_time = event->shadow_ctx_time + *now;
4443	*enabled = ctx_time - event->tstamp_enabled;
4444	*running = ctx_time - event->tstamp_running;
4445}
4446
4447static void perf_event_init_userpage(struct perf_event *event)
4448{
4449	struct perf_event_mmap_page *userpg;
4450	struct ring_buffer *rb;
4451
4452	rcu_read_lock();
4453	rb = rcu_dereference(event->rb);
4454	if (!rb)
4455		goto unlock;
4456
4457	userpg = rb->user_page;
4458
4459	/* Allow new userspace to detect that bit 0 is deprecated */
4460	userpg->cap_bit0_is_deprecated = 1;
4461	userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4462	userpg->data_offset = PAGE_SIZE;
4463	userpg->data_size = perf_data_size(rb);
4464
4465unlock:
4466	rcu_read_unlock();
4467}
4468
4469void __weak arch_perf_update_userpage(
4470	struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4471{
4472}
4473
4474/*
4475 * Callers need to ensure there can be no nesting of this function, otherwise
4476 * the seqlock logic goes bad. We can not serialize this because the arch
4477 * code calls this from NMI context.
4478 */
4479void perf_event_update_userpage(struct perf_event *event)
4480{
4481	struct perf_event_mmap_page *userpg;
4482	struct ring_buffer *rb;
4483	u64 enabled, running, now;
4484
4485	rcu_read_lock();
4486	rb = rcu_dereference(event->rb);
4487	if (!rb)
4488		goto unlock;
4489
4490	/*
4491	 * compute total_time_enabled, total_time_running
4492	 * based on snapshot values taken when the event
4493	 * was last scheduled in.
4494	 *
4495	 * we cannot simply called update_context_time()
4496	 * because of locking issue as we can be called in
4497	 * NMI context
4498	 */
4499	calc_timer_values(event, &now, &enabled, &running);
 
 
 
4500
4501	userpg = rb->user_page;
 
4502	/*
4503	 * Disable preemption so as to not let the corresponding user-space
4504	 * spin too long if we get preempted.
4505	 */
4506	preempt_disable();
4507	++userpg->lock;
4508	barrier();
4509	userpg->index = perf_event_index(event);
4510	userpg->offset = perf_event_count(event);
4511	if (userpg->index)
4512		userpg->offset -= local64_read(&event->hw.prev_count);
4513
4514	userpg->time_enabled = enabled +
4515			atomic64_read(&event->child_total_time_enabled);
4516
4517	userpg->time_running = running +
4518			atomic64_read(&event->child_total_time_running);
4519
4520	arch_perf_update_userpage(event, userpg, now);
4521
4522	barrier();
4523	++userpg->lock;
4524	preempt_enable();
4525unlock:
4526	rcu_read_unlock();
4527}
4528
4529static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4530{
4531	struct perf_event *event = vma->vm_file->private_data;
4532	struct ring_buffer *rb;
4533	int ret = VM_FAULT_SIGBUS;
4534
4535	if (vmf->flags & FAULT_FLAG_MKWRITE) {
4536		if (vmf->pgoff == 0)
4537			ret = 0;
4538		return ret;
4539	}
4540
4541	rcu_read_lock();
4542	rb = rcu_dereference(event->rb);
4543	if (!rb)
4544		goto unlock;
4545
4546	if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4547		goto unlock;
4548
4549	vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4550	if (!vmf->page)
4551		goto unlock;
4552
4553	get_page(vmf->page);
4554	vmf->page->mapping = vma->vm_file->f_mapping;
4555	vmf->page->index   = vmf->pgoff;
4556
4557	ret = 0;
4558unlock:
4559	rcu_read_unlock();
4560
4561	return ret;
4562}
4563
4564static void ring_buffer_attach(struct perf_event *event,
4565			       struct ring_buffer *rb)
4566{
4567	struct ring_buffer *old_rb = NULL;
4568	unsigned long flags;
4569
4570	if (event->rb) {
4571		/*
4572		 * Should be impossible, we set this when removing
4573		 * event->rb_entry and wait/clear when adding event->rb_entry.
4574		 */
4575		WARN_ON_ONCE(event->rcu_pending);
4576
4577		old_rb = event->rb;
4578		spin_lock_irqsave(&old_rb->event_lock, flags);
4579		list_del_rcu(&event->rb_entry);
4580		spin_unlock_irqrestore(&old_rb->event_lock, flags);
4581
4582		event->rcu_batches = get_state_synchronize_rcu();
4583		event->rcu_pending = 1;
4584	}
4585
4586	if (rb) {
4587		if (event->rcu_pending) {
4588			cond_synchronize_rcu(event->rcu_batches);
4589			event->rcu_pending = 0;
4590		}
4591
4592		spin_lock_irqsave(&rb->event_lock, flags);
4593		list_add_rcu(&event->rb_entry, &rb->event_list);
4594		spin_unlock_irqrestore(&rb->event_lock, flags);
4595	}
4596
4597	rcu_assign_pointer(event->rb, rb);
4598
4599	if (old_rb) {
4600		ring_buffer_put(old_rb);
4601		/*
4602		 * Since we detached before setting the new rb, so that we
4603		 * could attach the new rb, we could have missed a wakeup.
4604		 * Provide it now.
4605		 */
4606		wake_up_all(&event->waitq);
4607	}
4608}
4609
4610static void ring_buffer_wakeup(struct perf_event *event)
4611{
4612	struct ring_buffer *rb;
4613
4614	rcu_read_lock();
4615	rb = rcu_dereference(event->rb);
4616	if (rb) {
4617		list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4618			wake_up_all(&event->waitq);
4619	}
4620	rcu_read_unlock();
4621}
4622
4623struct ring_buffer *ring_buffer_get(struct perf_event *event)
4624{
4625	struct ring_buffer *rb;
4626
4627	rcu_read_lock();
4628	rb = rcu_dereference(event->rb);
4629	if (rb) {
4630		if (!atomic_inc_not_zero(&rb->refcount))
4631			rb = NULL;
4632	}
4633	rcu_read_unlock();
4634
4635	return rb;
4636}
4637
4638void ring_buffer_put(struct ring_buffer *rb)
4639{
4640	if (!atomic_dec_and_test(&rb->refcount))
4641		return;
4642
4643	WARN_ON_ONCE(!list_empty(&rb->event_list));
4644
4645	call_rcu(&rb->rcu_head, rb_free_rcu);
4646}
4647
4648static void perf_mmap_open(struct vm_area_struct *vma)
4649{
4650	struct perf_event *event = vma->vm_file->private_data;
4651
4652	atomic_inc(&event->mmap_count);
4653	atomic_inc(&event->rb->mmap_count);
4654
4655	if (vma->vm_pgoff)
4656		atomic_inc(&event->rb->aux_mmap_count);
4657
4658	if (event->pmu->event_mapped)
4659		event->pmu->event_mapped(event);
4660}
4661
4662/*
4663 * A buffer can be mmap()ed multiple times; either directly through the same
4664 * event, or through other events by use of perf_event_set_output().
4665 *
4666 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4667 * the buffer here, where we still have a VM context. This means we need
4668 * to detach all events redirecting to us.
4669 */
4670static void perf_mmap_close(struct vm_area_struct *vma)
4671{
4672	struct perf_event *event = vma->vm_file->private_data;
4673
4674	struct ring_buffer *rb = ring_buffer_get(event);
4675	struct user_struct *mmap_user = rb->mmap_user;
4676	int mmap_locked = rb->mmap_locked;
4677	unsigned long size = perf_data_size(rb);
4678
4679	if (event->pmu->event_unmapped)
4680		event->pmu->event_unmapped(event);
4681
4682	/*
4683	 * rb->aux_mmap_count will always drop before rb->mmap_count and
4684	 * event->mmap_count, so it is ok to use event->mmap_mutex to
4685	 * serialize with perf_mmap here.
4686	 */
4687	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4688	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4689		atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4690		vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4691
4692		rb_free_aux(rb);
4693		mutex_unlock(&event->mmap_mutex);
4694	}
4695
4696	atomic_dec(&rb->mmap_count);
4697
4698	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4699		goto out_put;
4700
4701	ring_buffer_attach(event, NULL);
4702	mutex_unlock(&event->mmap_mutex);
4703
4704	/* If there's still other mmap()s of this buffer, we're done. */
4705	if (atomic_read(&rb->mmap_count))
4706		goto out_put;
4707
4708	/*
4709	 * No other mmap()s, detach from all other events that might redirect
4710	 * into the now unreachable buffer. Somewhat complicated by the
4711	 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4712	 */
4713again:
4714	rcu_read_lock();
4715	list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4716		if (!atomic_long_inc_not_zero(&event->refcount)) {
4717			/*
4718			 * This event is en-route to free_event() which will
4719			 * detach it and remove it from the list.
4720			 */
4721			continue;
4722		}
4723		rcu_read_unlock();
4724
4725		mutex_lock(&event->mmap_mutex);
4726		/*
4727		 * Check we didn't race with perf_event_set_output() which can
4728		 * swizzle the rb from under us while we were waiting to
4729		 * acquire mmap_mutex.
4730		 *
4731		 * If we find a different rb; ignore this event, a next
4732		 * iteration will no longer find it on the list. We have to
4733		 * still restart the iteration to make sure we're not now
4734		 * iterating the wrong list.
4735		 */
4736		if (event->rb == rb)
4737			ring_buffer_attach(event, NULL);
4738
4739		mutex_unlock(&event->mmap_mutex);
4740		put_event(event);
4741
4742		/*
4743		 * Restart the iteration; either we're on the wrong list or
4744		 * destroyed its integrity by doing a deletion.
4745		 */
4746		goto again;
4747	}
4748	rcu_read_unlock();
4749
4750	/*
4751	 * It could be there's still a few 0-ref events on the list; they'll
4752	 * get cleaned up by free_event() -- they'll also still have their
4753	 * ref on the rb and will free it whenever they are done with it.
4754	 *
4755	 * Aside from that, this buffer is 'fully' detached and unmapped,
4756	 * undo the VM accounting.
4757	 */
4758
4759	atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4760	vma->vm_mm->pinned_vm -= mmap_locked;
4761	free_uid(mmap_user);
4762
4763out_put:
4764	ring_buffer_put(rb); /* could be last */
4765}
4766
4767static const struct vm_operations_struct perf_mmap_vmops = {
4768	.open		= perf_mmap_open,
4769	.close		= perf_mmap_close, /* non mergable */
4770	.fault		= perf_mmap_fault,
4771	.page_mkwrite	= perf_mmap_fault,
4772};
4773
4774static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4775{
4776	struct perf_event *event = file->private_data;
4777	unsigned long user_locked, user_lock_limit;
4778	struct user_struct *user = current_user();
4779	unsigned long locked, lock_limit;
4780	struct ring_buffer *rb = NULL;
4781	unsigned long vma_size;
4782	unsigned long nr_pages;
4783	long user_extra = 0, extra = 0;
4784	int ret = 0, flags = 0;
4785
4786	/*
4787	 * Don't allow mmap() of inherited per-task counters. This would
4788	 * create a performance issue due to all children writing to the
4789	 * same rb.
4790	 */
4791	if (event->cpu == -1 && event->attr.inherit)
4792		return -EINVAL;
4793
4794	if (!(vma->vm_flags & VM_SHARED))
4795		return -EINVAL;
4796
4797	vma_size = vma->vm_end - vma->vm_start;
4798
4799	if (vma->vm_pgoff == 0) {
4800		nr_pages = (vma_size / PAGE_SIZE) - 1;
4801	} else {
4802		/*
4803		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4804		 * mapped, all subsequent mappings should have the same size
4805		 * and offset. Must be above the normal perf buffer.
4806		 */
4807		u64 aux_offset, aux_size;
4808
4809		if (!event->rb)
4810			return -EINVAL;
4811
4812		nr_pages = vma_size / PAGE_SIZE;
4813
4814		mutex_lock(&event->mmap_mutex);
4815		ret = -EINVAL;
4816
4817		rb = event->rb;
4818		if (!rb)
4819			goto aux_unlock;
4820
4821		aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4822		aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4823
4824		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4825			goto aux_unlock;
4826
4827		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4828			goto aux_unlock;
4829
4830		/* already mapped with a different offset */
4831		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4832			goto aux_unlock;
4833
4834		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4835			goto aux_unlock;
4836
4837		/* already mapped with a different size */
4838		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4839			goto aux_unlock;
4840
4841		if (!is_power_of_2(nr_pages))
4842			goto aux_unlock;
4843
4844		if (!atomic_inc_not_zero(&rb->mmap_count))
4845			goto aux_unlock;
4846
4847		if (rb_has_aux(rb)) {
4848			atomic_inc(&rb->aux_mmap_count);
4849			ret = 0;
4850			goto unlock;
4851		}
4852
4853		atomic_set(&rb->aux_mmap_count, 1);
4854		user_extra = nr_pages;
4855
4856		goto accounting;
4857	}
4858
4859	/*
4860	 * If we have rb pages ensure they're a power-of-two number, so we
4861	 * can do bitmasks instead of modulo.
4862	 */
4863	if (nr_pages != 0 && !is_power_of_2(nr_pages))
4864		return -EINVAL;
4865
4866	if (vma_size != PAGE_SIZE * (1 + nr_pages))
4867		return -EINVAL;
4868
 
 
 
4869	WARN_ON_ONCE(event->ctx->parent_ctx);
4870again:
4871	mutex_lock(&event->mmap_mutex);
4872	if (event->rb) {
4873		if (event->rb->nr_pages != nr_pages) {
 
 
4874			ret = -EINVAL;
4875			goto unlock;
4876		}
4877
4878		if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4879			/*
4880			 * Raced against perf_mmap_close() through
4881			 * perf_event_set_output(). Try again, hope for better
4882			 * luck.
4883			 */
4884			mutex_unlock(&event->mmap_mutex);
4885			goto again;
4886		}
4887
4888		goto unlock;
4889	}
4890
4891	user_extra = nr_pages + 1;
4892
4893accounting:
4894	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4895
4896	/*
4897	 * Increase the limit linearly with more CPUs:
4898	 */
4899	user_lock_limit *= num_online_cpus();
4900
4901	user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4902
 
4903	if (user_locked > user_lock_limit)
4904		extra = user_locked - user_lock_limit;
4905
4906	lock_limit = rlimit(RLIMIT_MEMLOCK);
4907	lock_limit >>= PAGE_SHIFT;
4908	locked = vma->vm_mm->pinned_vm + extra;
4909
4910	if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4911		!capable(CAP_IPC_LOCK)) {
4912		ret = -EPERM;
4913		goto unlock;
4914	}
4915
4916	WARN_ON(!rb && event->rb);
4917
4918	if (vma->vm_flags & VM_WRITE)
4919		flags |= RING_BUFFER_WRITABLE;
4920
4921	if (!rb) {
4922		rb = rb_alloc(nr_pages,
4923			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
4924			      event->cpu, flags);
4925
4926		if (!rb) {
4927			ret = -ENOMEM;
4928			goto unlock;
4929		}
4930
4931		atomic_set(&rb->mmap_count, 1);
4932		rb->mmap_user = get_current_user();
4933		rb->mmap_locked = extra;
4934
4935		ring_buffer_attach(event, rb);
4936
4937		perf_event_init_userpage(event);
4938		perf_event_update_userpage(event);
4939	} else {
4940		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4941				   event->attr.aux_watermark, flags);
4942		if (!ret)
4943			rb->aux_mmap_locked = extra;
4944	}
 
4945
4946unlock:
4947	if (!ret) {
4948		atomic_long_add(user_extra, &user->locked_vm);
4949		vma->vm_mm->pinned_vm += extra;
4950
 
 
4951		atomic_inc(&event->mmap_count);
4952	} else if (rb) {
4953		atomic_dec(&rb->mmap_count);
4954	}
4955aux_unlock:
4956	mutex_unlock(&event->mmap_mutex);
4957
4958	/*
4959	 * Since pinned accounting is per vm we cannot allow fork() to copy our
4960	 * vma.
4961	 */
4962	vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4963	vma->vm_ops = &perf_mmap_vmops;
4964
4965	if (event->pmu->event_mapped)
4966		event->pmu->event_mapped(event);
4967
4968	return ret;
4969}
4970
4971static int perf_fasync(int fd, struct file *filp, int on)
4972{
4973	struct inode *inode = file_inode(filp);
4974	struct perf_event *event = filp->private_data;
4975	int retval;
4976
4977	inode_lock(inode);
4978	retval = fasync_helper(fd, filp, on, &event->fasync);
4979	inode_unlock(inode);
4980
4981	if (retval < 0)
4982		return retval;
4983
4984	return 0;
4985}
4986
4987static const struct file_operations perf_fops = {
4988	.llseek			= no_llseek,
4989	.release		= perf_release,
4990	.read			= perf_read,
4991	.poll			= perf_poll,
4992	.unlocked_ioctl		= perf_ioctl,
4993	.compat_ioctl		= perf_compat_ioctl,
4994	.mmap			= perf_mmap,
4995	.fasync			= perf_fasync,
4996};
4997
4998/*
4999 * Perf event wakeup
5000 *
5001 * If there's data, ensure we set the poll() state and publish everything
5002 * to user-space before waking everybody up.
5003 */
5004
5005static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5006{
5007	/* only the parent has fasync state */
5008	if (event->parent)
5009		event = event->parent;
5010	return &event->fasync;
5011}
5012
5013void perf_event_wakeup(struct perf_event *event)
5014{
5015	ring_buffer_wakeup(event);
5016
5017	if (event->pending_kill) {
5018		kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5019		event->pending_kill = 0;
5020	}
5021}
5022
5023static void perf_pending_event(struct irq_work *entry)
5024{
5025	struct perf_event *event = container_of(entry,
5026			struct perf_event, pending);
5027	int rctx;
5028
5029	rctx = perf_swevent_get_recursion_context();
5030	/*
5031	 * If we 'fail' here, that's OK, it means recursion is already disabled
5032	 * and we won't recurse 'further'.
5033	 */
5034
5035	if (event->pending_disable) {
5036		event->pending_disable = 0;
5037		perf_event_disable_local(event);
5038	}
5039
5040	if (event->pending_wakeup) {
5041		event->pending_wakeup = 0;
5042		perf_event_wakeup(event);
5043	}
5044
5045	if (rctx >= 0)
5046		perf_swevent_put_recursion_context(rctx);
5047}
5048
5049/*
5050 * We assume there is only KVM supporting the callbacks.
5051 * Later on, we might change it to a list if there is
5052 * another virtualization implementation supporting the callbacks.
5053 */
5054struct perf_guest_info_callbacks *perf_guest_cbs;
5055
5056int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5057{
5058	perf_guest_cbs = cbs;
5059	return 0;
5060}
5061EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5062
5063int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5064{
5065	perf_guest_cbs = NULL;
5066	return 0;
5067}
5068EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5069
5070static void
5071perf_output_sample_regs(struct perf_output_handle *handle,
5072			struct pt_regs *regs, u64 mask)
5073{
5074	int bit;
5075
5076	for_each_set_bit(bit, (const unsigned long *) &mask,
5077			 sizeof(mask) * BITS_PER_BYTE) {
5078		u64 val;
5079
5080		val = perf_reg_value(regs, bit);
5081		perf_output_put(handle, val);
5082	}
5083}
5084
5085static void perf_sample_regs_user(struct perf_regs *regs_user,
5086				  struct pt_regs *regs,
5087				  struct pt_regs *regs_user_copy)
5088{
5089	if (user_mode(regs)) {
5090		regs_user->abi = perf_reg_abi(current);
5091		regs_user->regs = regs;
5092	} else if (current->mm) {
5093		perf_get_regs_user(regs_user, regs, regs_user_copy);
5094	} else {
5095		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5096		regs_user->regs = NULL;
5097	}
5098}
5099
5100static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5101				  struct pt_regs *regs)
5102{
5103	regs_intr->regs = regs;
5104	regs_intr->abi  = perf_reg_abi(current);
5105}
5106
5107
5108/*
5109 * Get remaining task size from user stack pointer.
5110 *
5111 * It'd be better to take stack vma map and limit this more
5112 * precisly, but there's no way to get it safely under interrupt,
5113 * so using TASK_SIZE as limit.
5114 */
5115static u64 perf_ustack_task_size(struct pt_regs *regs)
5116{
5117	unsigned long addr = perf_user_stack_pointer(regs);
5118
5119	if (!addr || addr >= TASK_SIZE)
5120		return 0;
5121
5122	return TASK_SIZE - addr;
5123}
5124
5125static u16
5126perf_sample_ustack_size(u16 stack_size, u16 header_size,
5127			struct pt_regs *regs)
5128{
5129	u64 task_size;
5130
5131	/* No regs, no stack pointer, no dump. */
5132	if (!regs)
5133		return 0;
5134
5135	/*
5136	 * Check if we fit in with the requested stack size into the:
5137	 * - TASK_SIZE
5138	 *   If we don't, we limit the size to the TASK_SIZE.
5139	 *
5140	 * - remaining sample size
5141	 *   If we don't, we customize the stack size to
5142	 *   fit in to the remaining sample size.
5143	 */
5144
5145	task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5146	stack_size = min(stack_size, (u16) task_size);
5147
5148	/* Current header size plus static size and dynamic size. */
5149	header_size += 2 * sizeof(u64);
5150
5151	/* Do we fit in with the current stack dump size? */
5152	if ((u16) (header_size + stack_size) < header_size) {
5153		/*
5154		 * If we overflow the maximum size for the sample,
5155		 * we customize the stack dump size to fit in.
5156		 */
5157		stack_size = USHRT_MAX - header_size - sizeof(u64);
5158		stack_size = round_up(stack_size, sizeof(u64));
5159	}
5160
5161	return stack_size;
5162}
5163
5164static void
5165perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5166			  struct pt_regs *regs)
5167{
5168	/* Case of a kernel thread, nothing to dump */
5169	if (!regs) {
5170		u64 size = 0;
5171		perf_output_put(handle, size);
5172	} else {
5173		unsigned long sp;
5174		unsigned int rem;
5175		u64 dyn_size;
5176
5177		/*
5178		 * We dump:
5179		 * static size
5180		 *   - the size requested by user or the best one we can fit
5181		 *     in to the sample max size
5182		 * data
5183		 *   - user stack dump data
5184		 * dynamic size
5185		 *   - the actual dumped size
5186		 */
5187
5188		/* Static size. */
5189		perf_output_put(handle, dump_size);
5190
5191		/* Data. */
5192		sp = perf_user_stack_pointer(regs);
5193		rem = __output_copy_user(handle, (void *) sp, dump_size);
5194		dyn_size = dump_size - rem;
5195
5196		perf_output_skip(handle, rem);
5197
5198		/* Dynamic size. */
5199		perf_output_put(handle, dyn_size);
5200	}
5201}
5202
5203static void __perf_event_header__init_id(struct perf_event_header *header,
5204					 struct perf_sample_data *data,
5205					 struct perf_event *event)
5206{
5207	u64 sample_type = event->attr.sample_type;
5208
5209	data->type = sample_type;
5210	header->size += event->id_header_size;
5211
5212	if (sample_type & PERF_SAMPLE_TID) {
5213		/* namespace issues */
5214		data->tid_entry.pid = perf_event_pid(event, current);
5215		data->tid_entry.tid = perf_event_tid(event, current);
5216	}
5217
5218	if (sample_type & PERF_SAMPLE_TIME)
5219		data->time = perf_event_clock(event);
5220
5221	if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5222		data->id = primary_event_id(event);
5223
5224	if (sample_type & PERF_SAMPLE_STREAM_ID)
5225		data->stream_id = event->id;
5226
5227	if (sample_type & PERF_SAMPLE_CPU) {
5228		data->cpu_entry.cpu	 = raw_smp_processor_id();
5229		data->cpu_entry.reserved = 0;
5230	}
5231}
5232
5233void perf_event_header__init_id(struct perf_event_header *header,
5234				struct perf_sample_data *data,
5235				struct perf_event *event)
5236{
5237	if (event->attr.sample_id_all)
5238		__perf_event_header__init_id(header, data, event);
5239}
5240
5241static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5242					   struct perf_sample_data *data)
5243{
5244	u64 sample_type = data->type;
5245
5246	if (sample_type & PERF_SAMPLE_TID)
5247		perf_output_put(handle, data->tid_entry);
5248
5249	if (sample_type & PERF_SAMPLE_TIME)
5250		perf_output_put(handle, data->time);
5251
5252	if (sample_type & PERF_SAMPLE_ID)
5253		perf_output_put(handle, data->id);
5254
5255	if (sample_type & PERF_SAMPLE_STREAM_ID)
5256		perf_output_put(handle, data->stream_id);
5257
5258	if (sample_type & PERF_SAMPLE_CPU)
5259		perf_output_put(handle, data->cpu_entry);
5260
5261	if (sample_type & PERF_SAMPLE_IDENTIFIER)
5262		perf_output_put(handle, data->id);
5263}
5264
5265void perf_event__output_id_sample(struct perf_event *event,
5266				  struct perf_output_handle *handle,
5267				  struct perf_sample_data *sample)
5268{
5269	if (event->attr.sample_id_all)
5270		__perf_event__output_id_sample(handle, sample);
5271}
5272
5273static void perf_output_read_one(struct perf_output_handle *handle,
5274				 struct perf_event *event,
5275				 u64 enabled, u64 running)
5276{
5277	u64 read_format = event->attr.read_format;
5278	u64 values[4];
5279	int n = 0;
5280
5281	values[n++] = perf_event_count(event);
5282	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5283		values[n++] = enabled +
5284			atomic64_read(&event->child_total_time_enabled);
5285	}
5286	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5287		values[n++] = running +
5288			atomic64_read(&event->child_total_time_running);
5289	}
5290	if (read_format & PERF_FORMAT_ID)
5291		values[n++] = primary_event_id(event);
5292
5293	__output_copy(handle, values, n * sizeof(u64));
5294}
5295
5296/*
5297 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5298 */
5299static void perf_output_read_group(struct perf_output_handle *handle,
5300			    struct perf_event *event,
5301			    u64 enabled, u64 running)
5302{
5303	struct perf_event *leader = event->group_leader, *sub;
5304	u64 read_format = event->attr.read_format;
5305	u64 values[5];
5306	int n = 0;
5307
5308	values[n++] = 1 + leader->nr_siblings;
5309
5310	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5311		values[n++] = enabled;
5312
5313	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5314		values[n++] = running;
5315
5316	if (leader != event)
5317		leader->pmu->read(leader);
5318
5319	values[n++] = perf_event_count(leader);
5320	if (read_format & PERF_FORMAT_ID)
5321		values[n++] = primary_event_id(leader);
5322
5323	__output_copy(handle, values, n * sizeof(u64));
5324
5325	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5326		n = 0;
5327
5328		if ((sub != event) &&
5329		    (sub->state == PERF_EVENT_STATE_ACTIVE))
5330			sub->pmu->read(sub);
5331
5332		values[n++] = perf_event_count(sub);
5333		if (read_format & PERF_FORMAT_ID)
5334			values[n++] = primary_event_id(sub);
5335
5336		__output_copy(handle, values, n * sizeof(u64));
5337	}
5338}
5339
5340#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5341				 PERF_FORMAT_TOTAL_TIME_RUNNING)
5342
5343static void perf_output_read(struct perf_output_handle *handle,
5344			     struct perf_event *event)
5345{
5346	u64 enabled = 0, running = 0, now;
5347	u64 read_format = event->attr.read_format;
5348
5349	/*
5350	 * compute total_time_enabled, total_time_running
5351	 * based on snapshot values taken when the event
5352	 * was last scheduled in.
5353	 *
5354	 * we cannot simply called update_context_time()
5355	 * because of locking issue as we are called in
5356	 * NMI context
5357	 */
5358	if (read_format & PERF_FORMAT_TOTAL_TIMES)
5359		calc_timer_values(event, &now, &enabled, &running);
5360
5361	if (event->attr.read_format & PERF_FORMAT_GROUP)
5362		perf_output_read_group(handle, event, enabled, running);
5363	else
5364		perf_output_read_one(handle, event, enabled, running);
5365}
5366
5367void perf_output_sample(struct perf_output_handle *handle,
5368			struct perf_event_header *header,
5369			struct perf_sample_data *data,
5370			struct perf_event *event)
5371{
5372	u64 sample_type = data->type;
5373
5374	perf_output_put(handle, *header);
5375
5376	if (sample_type & PERF_SAMPLE_IDENTIFIER)
5377		perf_output_put(handle, data->id);
5378
5379	if (sample_type & PERF_SAMPLE_IP)
5380		perf_output_put(handle, data->ip);
5381
5382	if (sample_type & PERF_SAMPLE_TID)
5383		perf_output_put(handle, data->tid_entry);
5384
5385	if (sample_type & PERF_SAMPLE_TIME)
5386		perf_output_put(handle, data->time);
5387
5388	if (sample_type & PERF_SAMPLE_ADDR)
5389		perf_output_put(handle, data->addr);
5390
5391	if (sample_type & PERF_SAMPLE_ID)
5392		perf_output_put(handle, data->id);
5393
5394	if (sample_type & PERF_SAMPLE_STREAM_ID)
5395		perf_output_put(handle, data->stream_id);
5396
5397	if (sample_type & PERF_SAMPLE_CPU)
5398		perf_output_put(handle, data->cpu_entry);
5399
5400	if (sample_type & PERF_SAMPLE_PERIOD)
5401		perf_output_put(handle, data->period);
5402
5403	if (sample_type & PERF_SAMPLE_READ)
5404		perf_output_read(handle, event);
5405
5406	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5407		if (data->callchain) {
5408			int size = 1;
5409
5410			if (data->callchain)
5411				size += data->callchain->nr;
5412
5413			size *= sizeof(u64);
5414
5415			__output_copy(handle, data->callchain, size);
5416		} else {
5417			u64 nr = 0;
5418			perf_output_put(handle, nr);
5419		}
5420	}
5421
5422	if (sample_type & PERF_SAMPLE_RAW) {
5423		if (data->raw) {
5424			u32 raw_size = data->raw->size;
5425			u32 real_size = round_up(raw_size + sizeof(u32),
5426						 sizeof(u64)) - sizeof(u32);
5427			u64 zero = 0;
5428
5429			perf_output_put(handle, real_size);
5430			__output_copy(handle, data->raw->data, raw_size);
5431			if (real_size - raw_size)
5432				__output_copy(handle, &zero, real_size - raw_size);
5433		} else {
5434			struct {
5435				u32	size;
5436				u32	data;
5437			} raw = {
5438				.size = sizeof(u32),
5439				.data = 0,
5440			};
5441			perf_output_put(handle, raw);
5442		}
5443	}
5444
5445	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5446		if (data->br_stack) {
5447			size_t size;
5448
5449			size = data->br_stack->nr
5450			     * sizeof(struct perf_branch_entry);
5451
5452			perf_output_put(handle, data->br_stack->nr);
5453			perf_output_copy(handle, data->br_stack->entries, size);
5454		} else {
5455			/*
5456			 * we always store at least the value of nr
5457			 */
5458			u64 nr = 0;
5459			perf_output_put(handle, nr);
5460		}
5461	}
5462
5463	if (sample_type & PERF_SAMPLE_REGS_USER) {
5464		u64 abi = data->regs_user.abi;
5465
5466		/*
5467		 * If there are no regs to dump, notice it through
5468		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5469		 */
5470		perf_output_put(handle, abi);
5471
5472		if (abi) {
5473			u64 mask = event->attr.sample_regs_user;
5474			perf_output_sample_regs(handle,
5475						data->regs_user.regs,
5476						mask);
5477		}
5478	}
5479
5480	if (sample_type & PERF_SAMPLE_STACK_USER) {
5481		perf_output_sample_ustack(handle,
5482					  data->stack_user_size,
5483					  data->regs_user.regs);
5484	}
5485
5486	if (sample_type & PERF_SAMPLE_WEIGHT)
5487		perf_output_put(handle, data->weight);
5488
5489	if (sample_type & PERF_SAMPLE_DATA_SRC)
5490		perf_output_put(handle, data->data_src.val);
5491
5492	if (sample_type & PERF_SAMPLE_TRANSACTION)
5493		perf_output_put(handle, data->txn);
5494
5495	if (sample_type & PERF_SAMPLE_REGS_INTR) {
5496		u64 abi = data->regs_intr.abi;
5497		/*
5498		 * If there are no regs to dump, notice it through
5499		 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5500		 */
5501		perf_output_put(handle, abi);
5502
5503		if (abi) {
5504			u64 mask = event->attr.sample_regs_intr;
5505
5506			perf_output_sample_regs(handle,
5507						data->regs_intr.regs,
5508						mask);
5509		}
5510	}
5511
5512	if (!event->attr.watermark) {
5513		int wakeup_events = event->attr.wakeup_events;
5514
5515		if (wakeup_events) {
5516			struct ring_buffer *rb = handle->rb;
5517			int events = local_inc_return(&rb->events);
5518
5519			if (events >= wakeup_events) {
5520				local_sub(wakeup_events, &rb->events);
5521				local_inc(&rb->wakeup);
5522			}
5523		}
5524	}
5525}
5526
5527void perf_prepare_sample(struct perf_event_header *header,
5528			 struct perf_sample_data *data,
5529			 struct perf_event *event,
5530			 struct pt_regs *regs)
5531{
5532	u64 sample_type = event->attr.sample_type;
5533
5534	header->type = PERF_RECORD_SAMPLE;
5535	header->size = sizeof(*header) + event->header_size;
5536
5537	header->misc = 0;
5538	header->misc |= perf_misc_flags(regs);
5539
5540	__perf_event_header__init_id(header, data, event);
5541
5542	if (sample_type & PERF_SAMPLE_IP)
5543		data->ip = perf_instruction_pointer(regs);
5544
5545	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5546		int size = 1;
5547
5548		data->callchain = perf_callchain(event, regs);
5549
5550		if (data->callchain)
5551			size += data->callchain->nr;
5552
5553		header->size += size * sizeof(u64);
5554	}
5555
5556	if (sample_type & PERF_SAMPLE_RAW) {
5557		int size = sizeof(u32);
5558
5559		if (data->raw)
5560			size += data->raw->size;
5561		else
5562			size += sizeof(u32);
5563
5564		header->size += round_up(size, sizeof(u64));
5565	}
5566
5567	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5568		int size = sizeof(u64); /* nr */
5569		if (data->br_stack) {
5570			size += data->br_stack->nr
5571			      * sizeof(struct perf_branch_entry);
5572		}
5573		header->size += size;
5574	}
5575
5576	if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5577		perf_sample_regs_user(&data->regs_user, regs,
5578				      &data->regs_user_copy);
5579
5580	if (sample_type & PERF_SAMPLE_REGS_USER) {
5581		/* regs dump ABI info */
5582		int size = sizeof(u64);
5583
5584		if (data->regs_user.regs) {
5585			u64 mask = event->attr.sample_regs_user;
5586			size += hweight64(mask) * sizeof(u64);
5587		}
5588
5589		header->size += size;
5590	}
5591
5592	if (sample_type & PERF_SAMPLE_STACK_USER) {
5593		/*
5594		 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5595		 * processed as the last one or have additional check added
5596		 * in case new sample type is added, because we could eat
5597		 * up the rest of the sample size.
5598		 */
5599		u16 stack_size = event->attr.sample_stack_user;
5600		u16 size = sizeof(u64);
5601
5602		stack_size = perf_sample_ustack_size(stack_size, header->size,
5603						     data->regs_user.regs);
5604
5605		/*
5606		 * If there is something to dump, add space for the dump
5607		 * itself and for the field that tells the dynamic size,
5608		 * which is how many have been actually dumped.
5609		 */
5610		if (stack_size)
5611			size += sizeof(u64) + stack_size;
5612
5613		data->stack_user_size = stack_size;
5614		header->size += size;
5615	}
5616
5617	if (sample_type & PERF_SAMPLE_REGS_INTR) {
5618		/* regs dump ABI info */
5619		int size = sizeof(u64);
5620
5621		perf_sample_regs_intr(&data->regs_intr, regs);
5622
5623		if (data->regs_intr.regs) {
5624			u64 mask = event->attr.sample_regs_intr;
5625
5626			size += hweight64(mask) * sizeof(u64);
5627		}
5628
5629		header->size += size;
5630	}
5631}
5632
5633void perf_event_output(struct perf_event *event,
5634			struct perf_sample_data *data,
5635			struct pt_regs *regs)
5636{
5637	struct perf_output_handle handle;
5638	struct perf_event_header header;
5639
5640	/* protect the callchain buffers */
5641	rcu_read_lock();
5642
5643	perf_prepare_sample(&header, data, event, regs);
5644
5645	if (perf_output_begin(&handle, event, header.size))
5646		goto exit;
5647
5648	perf_output_sample(&handle, &header, data, event);
5649
5650	perf_output_end(&handle);
5651
5652exit:
5653	rcu_read_unlock();
5654}
5655
5656/*
5657 * read event_id
5658 */
5659
5660struct perf_read_event {
5661	struct perf_event_header	header;
5662
5663	u32				pid;
5664	u32				tid;
5665};
5666
5667static void
5668perf_event_read_event(struct perf_event *event,
5669			struct task_struct *task)
5670{
5671	struct perf_output_handle handle;
5672	struct perf_sample_data sample;
5673	struct perf_read_event read_event = {
5674		.header = {
5675			.type = PERF_RECORD_READ,
5676			.misc = 0,
5677			.size = sizeof(read_event) + event->read_size,
5678		},
5679		.pid = perf_event_pid(event, task),
5680		.tid = perf_event_tid(event, task),
5681	};
5682	int ret;
5683
5684	perf_event_header__init_id(&read_event.header, &sample, event);
5685	ret = perf_output_begin(&handle, event, read_event.header.size);
5686	if (ret)
5687		return;
5688
5689	perf_output_put(&handle, read_event);
5690	perf_output_read(&handle, event);
5691	perf_event__output_id_sample(event, &handle, &sample);
5692
5693	perf_output_end(&handle);
5694}
5695
5696typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5697
5698static void
5699perf_event_aux_ctx(struct perf_event_context *ctx,
5700		   perf_event_aux_output_cb output,
5701		   void *data)
5702{
5703	struct perf_event *event;
5704
5705	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5706		if (event->state < PERF_EVENT_STATE_INACTIVE)
5707			continue;
5708		if (!event_filter_match(event))
5709			continue;
5710		output(event, data);
5711	}
5712}
5713
5714static void
5715perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5716			struct perf_event_context *task_ctx)
5717{
5718	rcu_read_lock();
5719	preempt_disable();
5720	perf_event_aux_ctx(task_ctx, output, data);
5721	preempt_enable();
5722	rcu_read_unlock();
5723}
5724
5725static void
5726perf_event_aux(perf_event_aux_output_cb output, void *data,
5727	       struct perf_event_context *task_ctx)
5728{
5729	struct perf_cpu_context *cpuctx;
5730	struct perf_event_context *ctx;
5731	struct pmu *pmu;
5732	int ctxn;
5733
5734	/*
5735	 * If we have task_ctx != NULL we only notify
5736	 * the task context itself. The task_ctx is set
5737	 * only for EXIT events before releasing task
5738	 * context.
5739	 */
5740	if (task_ctx) {
5741		perf_event_aux_task_ctx(output, data, task_ctx);
5742		return;
5743	}
5744
5745	rcu_read_lock();
5746	list_for_each_entry_rcu(pmu, &pmus, entry) {
5747		cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5748		if (cpuctx->unique_pmu != pmu)
5749			goto next;
5750		perf_event_aux_ctx(&cpuctx->ctx, output, data);
5751		ctxn = pmu->task_ctx_nr;
5752		if (ctxn < 0)
5753			goto next;
5754		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5755		if (ctx)
5756			perf_event_aux_ctx(ctx, output, data);
5757next:
5758		put_cpu_ptr(pmu->pmu_cpu_context);
5759	}
5760	rcu_read_unlock();
5761}
5762
5763/*
5764 * task tracking -- fork/exit
5765 *
5766 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5767 */
5768
5769struct perf_task_event {
5770	struct task_struct		*task;
5771	struct perf_event_context	*task_ctx;
5772
5773	struct {
5774		struct perf_event_header	header;
5775
5776		u32				pid;
5777		u32				ppid;
5778		u32				tid;
5779		u32				ptid;
5780		u64				time;
5781	} event_id;
5782};
5783
5784static int perf_event_task_match(struct perf_event *event)
5785{
5786	return event->attr.comm  || event->attr.mmap ||
5787	       event->attr.mmap2 || event->attr.mmap_data ||
5788	       event->attr.task;
5789}
5790
5791static void perf_event_task_output(struct perf_event *event,
5792				   void *data)
5793{
5794	struct perf_task_event *task_event = data;
5795	struct perf_output_handle handle;
5796	struct perf_sample_data	sample;
5797	struct task_struct *task = task_event->task;
5798	int ret, size = task_event->event_id.header.size;
5799
5800	if (!perf_event_task_match(event))
5801		return;
5802
5803	perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5804
5805	ret = perf_output_begin(&handle, event,
5806				task_event->event_id.header.size);
5807	if (ret)
5808		goto out;
5809
5810	task_event->event_id.pid = perf_event_pid(event, task);
5811	task_event->event_id.ppid = perf_event_pid(event, current);
5812
5813	task_event->event_id.tid = perf_event_tid(event, task);
5814	task_event->event_id.ptid = perf_event_tid(event, current);
5815
5816	task_event->event_id.time = perf_event_clock(event);
5817
5818	perf_output_put(&handle, task_event->event_id);
5819
5820	perf_event__output_id_sample(event, &handle, &sample);
5821
5822	perf_output_end(&handle);
5823out:
5824	task_event->event_id.header.size = size;
5825}
5826
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5827static void perf_event_task(struct task_struct *task,
5828			      struct perf_event_context *task_ctx,
5829			      int new)
5830{
5831	struct perf_task_event task_event;
5832
5833	if (!atomic_read(&nr_comm_events) &&
5834	    !atomic_read(&nr_mmap_events) &&
5835	    !atomic_read(&nr_task_events))
5836		return;
5837
5838	task_event = (struct perf_task_event){
5839		.task	  = task,
5840		.task_ctx = task_ctx,
5841		.event_id    = {
5842			.header = {
5843				.type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5844				.misc = 0,
5845				.size = sizeof(task_event.event_id),
5846			},
5847			/* .pid  */
5848			/* .ppid */
5849			/* .tid  */
5850			/* .ptid */
5851			/* .time */
5852		},
5853	};
5854
5855	perf_event_aux(perf_event_task_output,
5856		       &task_event,
5857		       task_ctx);
5858}
5859
5860void perf_event_fork(struct task_struct *task)
5861{
5862	perf_event_task(task, NULL, 1);
5863}
5864
5865/*
5866 * comm tracking
5867 */
5868
5869struct perf_comm_event {
5870	struct task_struct	*task;
5871	char			*comm;
5872	int			comm_size;
5873
5874	struct {
5875		struct perf_event_header	header;
5876
5877		u32				pid;
5878		u32				tid;
5879	} event_id;
5880};
5881
5882static int perf_event_comm_match(struct perf_event *event)
5883{
5884	return event->attr.comm;
5885}
5886
5887static void perf_event_comm_output(struct perf_event *event,
5888				   void *data)
5889{
5890	struct perf_comm_event *comm_event = data;
5891	struct perf_output_handle handle;
5892	struct perf_sample_data sample;
5893	int size = comm_event->event_id.header.size;
5894	int ret;
5895
5896	if (!perf_event_comm_match(event))
5897		return;
5898
5899	perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5900	ret = perf_output_begin(&handle, event,
5901				comm_event->event_id.header.size);
5902
5903	if (ret)
5904		goto out;
5905
5906	comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5907	comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5908
5909	perf_output_put(&handle, comm_event->event_id);
5910	__output_copy(&handle, comm_event->comm,
5911				   comm_event->comm_size);
5912
5913	perf_event__output_id_sample(event, &handle, &sample);
5914
5915	perf_output_end(&handle);
5916out:
5917	comm_event->event_id.header.size = size;
5918}
5919
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5920static void perf_event_comm_event(struct perf_comm_event *comm_event)
5921{
 
 
5922	char comm[TASK_COMM_LEN];
5923	unsigned int size;
 
 
5924
5925	memset(comm, 0, sizeof(comm));
5926	strlcpy(comm, comm_event->task->comm, sizeof(comm));
5927	size = ALIGN(strlen(comm)+1, sizeof(u64));
5928
5929	comm_event->comm = comm;
5930	comm_event->comm_size = size;
5931
5932	comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
 
 
 
 
 
 
5933
5934	perf_event_aux(perf_event_comm_output,
5935		       comm_event,
5936		       NULL);
 
 
 
 
 
 
 
 
5937}
5938
5939void perf_event_comm(struct task_struct *task, bool exec)
5940{
5941	struct perf_comm_event comm_event;
 
 
 
 
 
 
 
 
 
 
5942
5943	if (!atomic_read(&nr_comm_events))
5944		return;
5945
5946	comm_event = (struct perf_comm_event){
5947		.task	= task,
5948		/* .comm      */
5949		/* .comm_size */
5950		.event_id  = {
5951			.header = {
5952				.type = PERF_RECORD_COMM,
5953				.misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5954				/* .size */
5955			},
5956			/* .pid */
5957			/* .tid */
5958		},
5959	};
5960
5961	perf_event_comm_event(&comm_event);
5962}
5963
5964/*
5965 * mmap tracking
5966 */
5967
5968struct perf_mmap_event {
5969	struct vm_area_struct	*vma;
5970
5971	const char		*file_name;
5972	int			file_size;
5973	int			maj, min;
5974	u64			ino;
5975	u64			ino_generation;
5976	u32			prot, flags;
5977
5978	struct {
5979		struct perf_event_header	header;
5980
5981		u32				pid;
5982		u32				tid;
5983		u64				start;
5984		u64				len;
5985		u64				pgoff;
5986	} event_id;
5987};
5988
5989static int perf_event_mmap_match(struct perf_event *event,
5990				 void *data)
5991{
5992	struct perf_mmap_event *mmap_event = data;
5993	struct vm_area_struct *vma = mmap_event->vma;
5994	int executable = vma->vm_flags & VM_EXEC;
5995
5996	return (!executable && event->attr.mmap_data) ||
5997	       (executable && (event->attr.mmap || event->attr.mmap2));
5998}
5999
6000static void perf_event_mmap_output(struct perf_event *event,
6001				   void *data)
6002{
6003	struct perf_mmap_event *mmap_event = data;
6004	struct perf_output_handle handle;
6005	struct perf_sample_data sample;
6006	int size = mmap_event->event_id.header.size;
6007	int ret;
6008
6009	if (!perf_event_mmap_match(event, data))
6010		return;
6011
6012	if (event->attr.mmap2) {
6013		mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6014		mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6015		mmap_event->event_id.header.size += sizeof(mmap_event->min);
6016		mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6017		mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6018		mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6019		mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6020	}
6021
6022	perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6023	ret = perf_output_begin(&handle, event,
6024				mmap_event->event_id.header.size);
6025	if (ret)
6026		goto out;
6027
6028	mmap_event->event_id.pid = perf_event_pid(event, current);
6029	mmap_event->event_id.tid = perf_event_tid(event, current);
6030
6031	perf_output_put(&handle, mmap_event->event_id);
6032
6033	if (event->attr.mmap2) {
6034		perf_output_put(&handle, mmap_event->maj);
6035		perf_output_put(&handle, mmap_event->min);
6036		perf_output_put(&handle, mmap_event->ino);
6037		perf_output_put(&handle, mmap_event->ino_generation);
6038		perf_output_put(&handle, mmap_event->prot);
6039		perf_output_put(&handle, mmap_event->flags);
6040	}
6041
6042	__output_copy(&handle, mmap_event->file_name,
6043				   mmap_event->file_size);
6044
6045	perf_event__output_id_sample(event, &handle, &sample);
6046
6047	perf_output_end(&handle);
6048out:
6049	mmap_event->event_id.header.size = size;
6050}
6051
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6052static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6053{
 
 
6054	struct vm_area_struct *vma = mmap_event->vma;
6055	struct file *file = vma->vm_file;
6056	int maj = 0, min = 0;
6057	u64 ino = 0, gen = 0;
6058	u32 prot = 0, flags = 0;
6059	unsigned int size;
6060	char tmp[16];
6061	char *buf = NULL;
6062	char *name;
 
 
6063
6064	if (file) {
6065		struct inode *inode;
6066		dev_t dev;
6067
6068		buf = kmalloc(PATH_MAX, GFP_KERNEL);
6069		if (!buf) {
6070			name = "//enomem";
6071			goto cpy_name;
6072		}
6073		/*
6074		 * d_path() works from the end of the rb backwards, so we
6075		 * need to add enough zero bytes after the string to handle
6076		 * the 64bit alignment we do later.
6077		 */
6078		name = file_path(file, buf, PATH_MAX - sizeof(u64));
 
 
 
 
 
6079		if (IS_ERR(name)) {
6080			name = "//toolong";
6081			goto cpy_name;
6082		}
6083		inode = file_inode(vma->vm_file);
6084		dev = inode->i_sb->s_dev;
6085		ino = inode->i_ino;
6086		gen = inode->i_generation;
6087		maj = MAJOR(dev);
6088		min = MINOR(dev);
6089
6090		if (vma->vm_flags & VM_READ)
6091			prot |= PROT_READ;
6092		if (vma->vm_flags & VM_WRITE)
6093			prot |= PROT_WRITE;
6094		if (vma->vm_flags & VM_EXEC)
6095			prot |= PROT_EXEC;
6096
6097		if (vma->vm_flags & VM_MAYSHARE)
6098			flags = MAP_SHARED;
6099		else
6100			flags = MAP_PRIVATE;
6101
6102		if (vma->vm_flags & VM_DENYWRITE)
6103			flags |= MAP_DENYWRITE;
6104		if (vma->vm_flags & VM_MAYEXEC)
6105			flags |= MAP_EXECUTABLE;
6106		if (vma->vm_flags & VM_LOCKED)
6107			flags |= MAP_LOCKED;
6108		if (vma->vm_flags & VM_HUGETLB)
6109			flags |= MAP_HUGETLB;
6110
6111		goto got_name;
6112	} else {
6113		if (vma->vm_ops && vma->vm_ops->name) {
6114			name = (char *) vma->vm_ops->name(vma);
6115			if (name)
6116				goto cpy_name;
6117		}
6118
6119		name = (char *)arch_vma_name(vma);
6120		if (name)
6121			goto cpy_name;
6122
6123		if (vma->vm_start <= vma->vm_mm->start_brk &&
6124				vma->vm_end >= vma->vm_mm->brk) {
6125			name = "[heap]";
6126			goto cpy_name;
6127		}
6128		if (vma->vm_start <= vma->vm_mm->start_stack &&
6129				vma->vm_end >= vma->vm_mm->start_stack) {
6130			name = "[stack]";
6131			goto cpy_name;
6132		}
6133
6134		name = "//anon";
6135		goto cpy_name;
6136	}
6137
6138cpy_name:
6139	strlcpy(tmp, name, sizeof(tmp));
6140	name = tmp;
6141got_name:
6142	/*
6143	 * Since our buffer works in 8 byte units we need to align our string
6144	 * size to a multiple of 8. However, we must guarantee the tail end is
6145	 * zero'd out to avoid leaking random bits to userspace.
6146	 */
6147	size = strlen(name)+1;
6148	while (!IS_ALIGNED(size, sizeof(u64)))
6149		name[size++] = '\0';
6150
6151	mmap_event->file_name = name;
6152	mmap_event->file_size = size;
6153	mmap_event->maj = maj;
6154	mmap_event->min = min;
6155	mmap_event->ino = ino;
6156	mmap_event->ino_generation = gen;
6157	mmap_event->prot = prot;
6158	mmap_event->flags = flags;
6159
6160	if (!(vma->vm_flags & VM_EXEC))
6161		mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6162
6163	mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6164
6165	perf_event_aux(perf_event_mmap_output,
6166		       mmap_event,
6167		       NULL);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6168
6169	kfree(buf);
6170}
6171
6172void perf_event_mmap(struct vm_area_struct *vma)
6173{
6174	struct perf_mmap_event mmap_event;
6175
6176	if (!atomic_read(&nr_mmap_events))
6177		return;
6178
6179	mmap_event = (struct perf_mmap_event){
6180		.vma	= vma,
6181		/* .file_name */
6182		/* .file_size */
6183		.event_id  = {
6184			.header = {
6185				.type = PERF_RECORD_MMAP,
6186				.misc = PERF_RECORD_MISC_USER,
6187				/* .size */
6188			},
6189			/* .pid */
6190			/* .tid */
6191			.start  = vma->vm_start,
6192			.len    = vma->vm_end - vma->vm_start,
6193			.pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
6194		},
6195		/* .maj (attr_mmap2 only) */
6196		/* .min (attr_mmap2 only) */
6197		/* .ino (attr_mmap2 only) */
6198		/* .ino_generation (attr_mmap2 only) */
6199		/* .prot (attr_mmap2 only) */
6200		/* .flags (attr_mmap2 only) */
6201	};
6202
6203	perf_event_mmap_event(&mmap_event);
6204}
6205
6206void perf_event_aux_event(struct perf_event *event, unsigned long head,
6207			  unsigned long size, u64 flags)
6208{
6209	struct perf_output_handle handle;
6210	struct perf_sample_data sample;
6211	struct perf_aux_event {
6212		struct perf_event_header	header;
6213		u64				offset;
6214		u64				size;
6215		u64				flags;
6216	} rec = {
6217		.header = {
6218			.type = PERF_RECORD_AUX,
6219			.misc = 0,
6220			.size = sizeof(rec),
6221		},
6222		.offset		= head,
6223		.size		= size,
6224		.flags		= flags,
6225	};
6226	int ret;
6227
6228	perf_event_header__init_id(&rec.header, &sample, event);
6229	ret = perf_output_begin(&handle, event, rec.header.size);
6230
6231	if (ret)
6232		return;
6233
6234	perf_output_put(&handle, rec);
6235	perf_event__output_id_sample(event, &handle, &sample);
6236
6237	perf_output_end(&handle);
6238}
6239
6240/*
6241 * Lost/dropped samples logging
6242 */
6243void perf_log_lost_samples(struct perf_event *event, u64 lost)
6244{
6245	struct perf_output_handle handle;
6246	struct perf_sample_data sample;
6247	int ret;
6248
6249	struct {
6250		struct perf_event_header	header;
6251		u64				lost;
6252	} lost_samples_event = {
6253		.header = {
6254			.type = PERF_RECORD_LOST_SAMPLES,
6255			.misc = 0,
6256			.size = sizeof(lost_samples_event),
6257		},
6258		.lost		= lost,
6259	};
6260
6261	perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6262
6263	ret = perf_output_begin(&handle, event,
6264				lost_samples_event.header.size);
6265	if (ret)
6266		return;
6267
6268	perf_output_put(&handle, lost_samples_event);
6269	perf_event__output_id_sample(event, &handle, &sample);
6270	perf_output_end(&handle);
6271}
6272
6273/*
6274 * context_switch tracking
6275 */
6276
6277struct perf_switch_event {
6278	struct task_struct	*task;
6279	struct task_struct	*next_prev;
6280
6281	struct {
6282		struct perf_event_header	header;
6283		u32				next_prev_pid;
6284		u32				next_prev_tid;
6285	} event_id;
6286};
6287
6288static int perf_event_switch_match(struct perf_event *event)
6289{
6290	return event->attr.context_switch;
6291}
6292
6293static void perf_event_switch_output(struct perf_event *event, void *data)
6294{
6295	struct perf_switch_event *se = data;
6296	struct perf_output_handle handle;
6297	struct perf_sample_data sample;
6298	int ret;
6299
6300	if (!perf_event_switch_match(event))
6301		return;
6302
6303	/* Only CPU-wide events are allowed to see next/prev pid/tid */
6304	if (event->ctx->task) {
6305		se->event_id.header.type = PERF_RECORD_SWITCH;
6306		se->event_id.header.size = sizeof(se->event_id.header);
6307	} else {
6308		se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6309		se->event_id.header.size = sizeof(se->event_id);
6310		se->event_id.next_prev_pid =
6311					perf_event_pid(event, se->next_prev);
6312		se->event_id.next_prev_tid =
6313					perf_event_tid(event, se->next_prev);
6314	}
6315
6316	perf_event_header__init_id(&se->event_id.header, &sample, event);
6317
6318	ret = perf_output_begin(&handle, event, se->event_id.header.size);
6319	if (ret)
6320		return;
6321
6322	if (event->ctx->task)
6323		perf_output_put(&handle, se->event_id.header);
6324	else
6325		perf_output_put(&handle, se->event_id);
6326
6327	perf_event__output_id_sample(event, &handle, &sample);
6328
6329	perf_output_end(&handle);
6330}
6331
6332static void perf_event_switch(struct task_struct *task,
6333			      struct task_struct *next_prev, bool sched_in)
6334{
6335	struct perf_switch_event switch_event;
6336
6337	/* N.B. caller checks nr_switch_events != 0 */
6338
6339	switch_event = (struct perf_switch_event){
6340		.task		= task,
6341		.next_prev	= next_prev,
6342		.event_id	= {
6343			.header = {
6344				/* .type */
6345				.misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6346				/* .size */
6347			},
6348			/* .next_prev_pid */
6349			/* .next_prev_tid */
6350		},
6351	};
6352
6353	perf_event_aux(perf_event_switch_output,
6354		       &switch_event,
6355		       NULL);
6356}
6357
6358/*
6359 * IRQ throttle logging
6360 */
6361
6362static void perf_log_throttle(struct perf_event *event, int enable)
6363{
6364	struct perf_output_handle handle;
6365	struct perf_sample_data sample;
6366	int ret;
6367
6368	struct {
6369		struct perf_event_header	header;
6370		u64				time;
6371		u64				id;
6372		u64				stream_id;
6373	} throttle_event = {
6374		.header = {
6375			.type = PERF_RECORD_THROTTLE,
6376			.misc = 0,
6377			.size = sizeof(throttle_event),
6378		},
6379		.time		= perf_event_clock(event),
6380		.id		= primary_event_id(event),
6381		.stream_id	= event->id,
6382	};
6383
6384	if (enable)
6385		throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6386
6387	perf_event_header__init_id(&throttle_event.header, &sample, event);
6388
6389	ret = perf_output_begin(&handle, event,
6390				throttle_event.header.size);
6391	if (ret)
6392		return;
6393
6394	perf_output_put(&handle, throttle_event);
6395	perf_event__output_id_sample(event, &handle, &sample);
6396	perf_output_end(&handle);
6397}
6398
6399static void perf_log_itrace_start(struct perf_event *event)
6400{
6401	struct perf_output_handle handle;
6402	struct perf_sample_data sample;
6403	struct perf_aux_event {
6404		struct perf_event_header        header;
6405		u32				pid;
6406		u32				tid;
6407	} rec;
6408	int ret;
6409
6410	if (event->parent)
6411		event = event->parent;
6412
6413	if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6414	    event->hw.itrace_started)
6415		return;
6416
6417	rec.header.type	= PERF_RECORD_ITRACE_START;
6418	rec.header.misc	= 0;
6419	rec.header.size	= sizeof(rec);
6420	rec.pid	= perf_event_pid(event, current);
6421	rec.tid	= perf_event_tid(event, current);
6422
6423	perf_event_header__init_id(&rec.header, &sample, event);
6424	ret = perf_output_begin(&handle, event, rec.header.size);
6425
6426	if (ret)
6427		return;
6428
6429	perf_output_put(&handle, rec);
6430	perf_event__output_id_sample(event, &handle, &sample);
6431
6432	perf_output_end(&handle);
6433}
6434
6435/*
6436 * Generic event overflow handling, sampling.
6437 */
6438
6439static int __perf_event_overflow(struct perf_event *event,
6440				   int throttle, struct perf_sample_data *data,
6441				   struct pt_regs *regs)
6442{
6443	int events = atomic_read(&event->event_limit);
6444	struct hw_perf_event *hwc = &event->hw;
6445	u64 seq;
6446	int ret = 0;
6447
6448	/*
6449	 * Non-sampling counters might still use the PMI to fold short
6450	 * hardware counters, ignore those.
6451	 */
6452	if (unlikely(!is_sampling_event(event)))
6453		return 0;
6454
6455	seq = __this_cpu_read(perf_throttled_seq);
6456	if (seq != hwc->interrupts_seq) {
6457		hwc->interrupts_seq = seq;
6458		hwc->interrupts = 1;
6459	} else {
6460		hwc->interrupts++;
6461		if (unlikely(throttle
6462			     && hwc->interrupts >= max_samples_per_tick)) {
6463			__this_cpu_inc(perf_throttled_count);
6464			tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
6465			hwc->interrupts = MAX_INTERRUPTS;
6466			perf_log_throttle(event, 0);
6467			ret = 1;
6468		}
6469	}
 
6470
6471	if (event->attr.freq) {
6472		u64 now = perf_clock();
6473		s64 delta = now - hwc->freq_time_stamp;
6474
6475		hwc->freq_time_stamp = now;
6476
6477		if (delta > 0 && delta < 2*TICK_NSEC)
6478			perf_adjust_period(event, delta, hwc->last_period, true);
6479	}
6480
6481	/*
6482	 * XXX event_limit might not quite work as expected on inherited
6483	 * events
6484	 */
6485
6486	event->pending_kill = POLL_IN;
6487	if (events && atomic_dec_and_test(&event->event_limit)) {
6488		ret = 1;
6489		event->pending_kill = POLL_HUP;
6490		event->pending_disable = 1;
6491		irq_work_queue(&event->pending);
6492	}
6493
6494	if (event->overflow_handler)
6495		event->overflow_handler(event, data, regs);
6496	else
6497		perf_event_output(event, data, regs);
6498
6499	if (*perf_event_fasync(event) && event->pending_kill) {
6500		event->pending_wakeup = 1;
6501		irq_work_queue(&event->pending);
6502	}
6503
6504	return ret;
6505}
6506
6507int perf_event_overflow(struct perf_event *event,
6508			  struct perf_sample_data *data,
6509			  struct pt_regs *regs)
6510{
6511	return __perf_event_overflow(event, 1, data, regs);
6512}
6513
6514/*
6515 * Generic software event infrastructure
6516 */
6517
6518struct swevent_htable {
6519	struct swevent_hlist		*swevent_hlist;
6520	struct mutex			hlist_mutex;
6521	int				hlist_refcount;
6522
6523	/* Recursion avoidance in each contexts */
6524	int				recursion[PERF_NR_CONTEXTS];
6525};
6526
6527static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6528
6529/*
6530 * We directly increment event->count and keep a second value in
6531 * event->hw.period_left to count intervals. This period event
6532 * is kept in the range [-sample_period, 0] so that we can use the
6533 * sign as trigger.
6534 */
6535
6536u64 perf_swevent_set_period(struct perf_event *event)
6537{
6538	struct hw_perf_event *hwc = &event->hw;
6539	u64 period = hwc->last_period;
6540	u64 nr, offset;
6541	s64 old, val;
6542
6543	hwc->last_period = hwc->sample_period;
6544
6545again:
6546	old = val = local64_read(&hwc->period_left);
6547	if (val < 0)
6548		return 0;
6549
6550	nr = div64_u64(period + val, period);
6551	offset = nr * period;
6552	val -= offset;
6553	if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6554		goto again;
6555
6556	return nr;
6557}
6558
6559static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6560				    struct perf_sample_data *data,
6561				    struct pt_regs *regs)
6562{
6563	struct hw_perf_event *hwc = &event->hw;
6564	int throttle = 0;
6565
 
6566	if (!overflow)
6567		overflow = perf_swevent_set_period(event);
6568
6569	if (hwc->interrupts == MAX_INTERRUPTS)
6570		return;
6571
6572	for (; overflow; overflow--) {
6573		if (__perf_event_overflow(event, throttle,
6574					    data, regs)) {
6575			/*
6576			 * We inhibit the overflow from happening when
6577			 * hwc->interrupts == MAX_INTERRUPTS.
6578			 */
6579			break;
6580		}
6581		throttle = 1;
6582	}
6583}
6584
6585static void perf_swevent_event(struct perf_event *event, u64 nr,
6586			       struct perf_sample_data *data,
6587			       struct pt_regs *regs)
6588{
6589	struct hw_perf_event *hwc = &event->hw;
6590
6591	local64_add(nr, &event->count);
6592
6593	if (!regs)
6594		return;
6595
6596	if (!is_sampling_event(event))
6597		return;
6598
6599	if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6600		data->period = nr;
6601		return perf_swevent_overflow(event, 1, data, regs);
6602	} else
6603		data->period = event->hw.last_period;
6604
6605	if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6606		return perf_swevent_overflow(event, 1, data, regs);
6607
6608	if (local64_add_negative(nr, &hwc->period_left))
6609		return;
6610
6611	perf_swevent_overflow(event, 0, data, regs);
6612}
6613
6614static int perf_exclude_event(struct perf_event *event,
6615			      struct pt_regs *regs)
6616{
6617	if (event->hw.state & PERF_HES_STOPPED)
6618		return 1;
6619
6620	if (regs) {
6621		if (event->attr.exclude_user && user_mode(regs))
6622			return 1;
6623
6624		if (event->attr.exclude_kernel && !user_mode(regs))
6625			return 1;
6626	}
6627
6628	return 0;
6629}
6630
6631static int perf_swevent_match(struct perf_event *event,
6632				enum perf_type_id type,
6633				u32 event_id,
6634				struct perf_sample_data *data,
6635				struct pt_regs *regs)
6636{
6637	if (event->attr.type != type)
6638		return 0;
6639
6640	if (event->attr.config != event_id)
6641		return 0;
6642
6643	if (perf_exclude_event(event, regs))
6644		return 0;
6645
6646	return 1;
6647}
6648
6649static inline u64 swevent_hash(u64 type, u32 event_id)
6650{
6651	u64 val = event_id | (type << 32);
6652
6653	return hash_64(val, SWEVENT_HLIST_BITS);
6654}
6655
6656static inline struct hlist_head *
6657__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6658{
6659	u64 hash = swevent_hash(type, event_id);
6660
6661	return &hlist->heads[hash];
6662}
6663
6664/* For the read side: events when they trigger */
6665static inline struct hlist_head *
6666find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6667{
6668	struct swevent_hlist *hlist;
6669
6670	hlist = rcu_dereference(swhash->swevent_hlist);
6671	if (!hlist)
6672		return NULL;
6673
6674	return __find_swevent_head(hlist, type, event_id);
6675}
6676
6677/* For the event head insertion and removal in the hlist */
6678static inline struct hlist_head *
6679find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6680{
6681	struct swevent_hlist *hlist;
6682	u32 event_id = event->attr.config;
6683	u64 type = event->attr.type;
6684
6685	/*
6686	 * Event scheduling is always serialized against hlist allocation
6687	 * and release. Which makes the protected version suitable here.
6688	 * The context lock guarantees that.
6689	 */
6690	hlist = rcu_dereference_protected(swhash->swevent_hlist,
6691					  lockdep_is_held(&event->ctx->lock));
6692	if (!hlist)
6693		return NULL;
6694
6695	return __find_swevent_head(hlist, type, event_id);
6696}
6697
6698static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6699				    u64 nr,
6700				    struct perf_sample_data *data,
6701				    struct pt_regs *regs)
6702{
6703	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6704	struct perf_event *event;
 
6705	struct hlist_head *head;
6706
6707	rcu_read_lock();
6708	head = find_swevent_head_rcu(swhash, type, event_id);
6709	if (!head)
6710		goto end;
6711
6712	hlist_for_each_entry_rcu(event, head, hlist_entry) {
6713		if (perf_swevent_match(event, type, event_id, data, regs))
6714			perf_swevent_event(event, nr, data, regs);
6715	}
6716end:
6717	rcu_read_unlock();
6718}
6719
6720DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6721
6722int perf_swevent_get_recursion_context(void)
6723{
6724	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6725
6726	return get_recursion_context(swhash->recursion);
6727}
6728EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6729
6730inline void perf_swevent_put_recursion_context(int rctx)
6731{
6732	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6733
6734	put_recursion_context(swhash->recursion, rctx);
6735}
6736
6737void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6738{
6739	struct perf_sample_data data;
6740
6741	if (WARN_ON_ONCE(!regs))
6742		return;
6743
6744	perf_sample_data_init(&data, addr, 0);
6745	do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6746}
6747
6748void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6749{
 
6750	int rctx;
6751
6752	preempt_disable_notrace();
6753	rctx = perf_swevent_get_recursion_context();
6754	if (unlikely(rctx < 0))
6755		goto fail;
 
 
6756
6757	___perf_sw_event(event_id, nr, regs, addr);
6758
6759	perf_swevent_put_recursion_context(rctx);
6760fail:
6761	preempt_enable_notrace();
6762}
6763
6764static void perf_swevent_read(struct perf_event *event)
6765{
6766}
6767
6768static int perf_swevent_add(struct perf_event *event, int flags)
6769{
6770	struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6771	struct hw_perf_event *hwc = &event->hw;
6772	struct hlist_head *head;
6773
6774	if (is_sampling_event(event)) {
6775		hwc->last_period = hwc->sample_period;
6776		perf_swevent_set_period(event);
6777	}
6778
6779	hwc->state = !(flags & PERF_EF_START);
6780
6781	head = find_swevent_head(swhash, event);
6782	if (WARN_ON_ONCE(!head))
6783		return -EINVAL;
6784
6785	hlist_add_head_rcu(&event->hlist_entry, head);
6786	perf_event_update_userpage(event);
6787
6788	return 0;
6789}
6790
6791static void perf_swevent_del(struct perf_event *event, int flags)
6792{
6793	hlist_del_rcu(&event->hlist_entry);
6794}
6795
6796static void perf_swevent_start(struct perf_event *event, int flags)
6797{
6798	event->hw.state = 0;
6799}
6800
6801static void perf_swevent_stop(struct perf_event *event, int flags)
6802{
6803	event->hw.state = PERF_HES_STOPPED;
6804}
6805
6806/* Deref the hlist from the update side */
6807static inline struct swevent_hlist *
6808swevent_hlist_deref(struct swevent_htable *swhash)
6809{
6810	return rcu_dereference_protected(swhash->swevent_hlist,
6811					 lockdep_is_held(&swhash->hlist_mutex));
6812}
6813
6814static void swevent_hlist_release(struct swevent_htable *swhash)
6815{
6816	struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6817
6818	if (!hlist)
6819		return;
6820
6821	RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6822	kfree_rcu(hlist, rcu_head);
6823}
6824
6825static void swevent_hlist_put_cpu(int cpu)
6826{
6827	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6828
6829	mutex_lock(&swhash->hlist_mutex);
6830
6831	if (!--swhash->hlist_refcount)
6832		swevent_hlist_release(swhash);
6833
6834	mutex_unlock(&swhash->hlist_mutex);
6835}
6836
6837static void swevent_hlist_put(void)
6838{
6839	int cpu;
6840
 
 
 
 
 
6841	for_each_possible_cpu(cpu)
6842		swevent_hlist_put_cpu(cpu);
6843}
6844
6845static int swevent_hlist_get_cpu(int cpu)
6846{
6847	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6848	int err = 0;
6849
6850	mutex_lock(&swhash->hlist_mutex);
 
6851	if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6852		struct swevent_hlist *hlist;
6853
6854		hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6855		if (!hlist) {
6856			err = -ENOMEM;
6857			goto exit;
6858		}
6859		rcu_assign_pointer(swhash->swevent_hlist, hlist);
6860	}
6861	swhash->hlist_refcount++;
6862exit:
6863	mutex_unlock(&swhash->hlist_mutex);
6864
6865	return err;
6866}
6867
6868static int swevent_hlist_get(void)
6869{
6870	int err, cpu, failed_cpu;
 
 
 
 
6871
6872	get_online_cpus();
6873	for_each_possible_cpu(cpu) {
6874		err = swevent_hlist_get_cpu(cpu);
6875		if (err) {
6876			failed_cpu = cpu;
6877			goto fail;
6878		}
6879	}
6880	put_online_cpus();
6881
6882	return 0;
6883fail:
6884	for_each_possible_cpu(cpu) {
6885		if (cpu == failed_cpu)
6886			break;
6887		swevent_hlist_put_cpu(cpu);
6888	}
6889
6890	put_online_cpus();
6891	return err;
6892}
6893
6894struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6895
6896static void sw_perf_event_destroy(struct perf_event *event)
6897{
6898	u64 event_id = event->attr.config;
6899
6900	WARN_ON(event->parent);
6901
6902	static_key_slow_dec(&perf_swevent_enabled[event_id]);
6903	swevent_hlist_put();
6904}
6905
6906static int perf_swevent_init(struct perf_event *event)
6907{
6908	u64 event_id = event->attr.config;
6909
6910	if (event->attr.type != PERF_TYPE_SOFTWARE)
6911		return -ENOENT;
6912
6913	/*
6914	 * no branch sampling for software events
6915	 */
6916	if (has_branch_stack(event))
6917		return -EOPNOTSUPP;
6918
6919	switch (event_id) {
6920	case PERF_COUNT_SW_CPU_CLOCK:
6921	case PERF_COUNT_SW_TASK_CLOCK:
6922		return -ENOENT;
6923
6924	default:
6925		break;
6926	}
6927
6928	if (event_id >= PERF_COUNT_SW_MAX)
6929		return -ENOENT;
6930
6931	if (!event->parent) {
6932		int err;
6933
6934		err = swevent_hlist_get();
6935		if (err)
6936			return err;
6937
6938		static_key_slow_inc(&perf_swevent_enabled[event_id]);
6939		event->destroy = sw_perf_event_destroy;
6940	}
6941
6942	return 0;
6943}
6944
6945static struct pmu perf_swevent = {
6946	.task_ctx_nr	= perf_sw_context,
6947
6948	.capabilities	= PERF_PMU_CAP_NO_NMI,
6949
6950	.event_init	= perf_swevent_init,
6951	.add		= perf_swevent_add,
6952	.del		= perf_swevent_del,
6953	.start		= perf_swevent_start,
6954	.stop		= perf_swevent_stop,
6955	.read		= perf_swevent_read,
6956};
6957
6958#ifdef CONFIG_EVENT_TRACING
6959
6960static int perf_tp_filter_match(struct perf_event *event,
6961				struct perf_sample_data *data)
6962{
6963	void *record = data->raw->data;
6964
6965	/* only top level events have filters set */
6966	if (event->parent)
6967		event = event->parent;
6968
6969	if (likely(!event->filter) || filter_match_preds(event->filter, record))
6970		return 1;
6971	return 0;
6972}
6973
6974static int perf_tp_event_match(struct perf_event *event,
6975				struct perf_sample_data *data,
6976				struct pt_regs *regs)
6977{
6978	if (event->hw.state & PERF_HES_STOPPED)
6979		return 0;
6980	/*
6981	 * All tracepoints are from kernel-space.
6982	 */
6983	if (event->attr.exclude_kernel)
6984		return 0;
6985
6986	if (!perf_tp_filter_match(event, data))
6987		return 0;
6988
6989	return 1;
6990}
6991
6992void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6993		   struct pt_regs *regs, struct hlist_head *head, int rctx,
6994		   struct task_struct *task)
6995{
6996	struct perf_sample_data data;
6997	struct perf_event *event;
 
6998
6999	struct perf_raw_record raw = {
7000		.size = entry_size,
7001		.data = record,
7002	};
7003
7004	perf_sample_data_init(&data, addr, 0);
7005	data.raw = &raw;
7006
7007	hlist_for_each_entry_rcu(event, head, hlist_entry) {
7008		if (perf_tp_event_match(event, &data, regs))
7009			perf_swevent_event(event, count, &data, regs);
7010	}
7011
7012	/*
7013	 * If we got specified a target task, also iterate its context and
7014	 * deliver this event there too.
7015	 */
7016	if (task && task != current) {
7017		struct perf_event_context *ctx;
7018		struct trace_entry *entry = record;
7019
7020		rcu_read_lock();
7021		ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7022		if (!ctx)
7023			goto unlock;
7024
7025		list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7026			if (event->attr.type != PERF_TYPE_TRACEPOINT)
7027				continue;
7028			if (event->attr.config != entry->type)
7029				continue;
7030			if (perf_tp_event_match(event, &data, regs))
7031				perf_swevent_event(event, count, &data, regs);
7032		}
7033unlock:
7034		rcu_read_unlock();
7035	}
7036
7037	perf_swevent_put_recursion_context(rctx);
7038}
7039EXPORT_SYMBOL_GPL(perf_tp_event);
7040
7041static void tp_perf_event_destroy(struct perf_event *event)
7042{
7043	perf_trace_destroy(event);
7044}
7045
7046static int perf_tp_event_init(struct perf_event *event)
7047{
7048	int err;
7049
7050	if (event->attr.type != PERF_TYPE_TRACEPOINT)
7051		return -ENOENT;
7052
7053	/*
7054	 * no branch sampling for tracepoint events
7055	 */
7056	if (has_branch_stack(event))
7057		return -EOPNOTSUPP;
7058
7059	err = perf_trace_init(event);
7060	if (err)
7061		return err;
7062
7063	event->destroy = tp_perf_event_destroy;
7064
7065	return 0;
7066}
7067
7068static struct pmu perf_tracepoint = {
7069	.task_ctx_nr	= perf_sw_context,
7070
7071	.event_init	= perf_tp_event_init,
7072	.add		= perf_trace_add,
7073	.del		= perf_trace_del,
7074	.start		= perf_swevent_start,
7075	.stop		= perf_swevent_stop,
7076	.read		= perf_swevent_read,
7077};
7078
7079static inline void perf_tp_register(void)
7080{
7081	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7082}
7083
7084static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7085{
7086	char *filter_str;
7087	int ret;
7088
7089	if (event->attr.type != PERF_TYPE_TRACEPOINT)
7090		return -EINVAL;
7091
7092	filter_str = strndup_user(arg, PAGE_SIZE);
7093	if (IS_ERR(filter_str))
7094		return PTR_ERR(filter_str);
7095
7096	ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7097
7098	kfree(filter_str);
7099	return ret;
7100}
7101
7102static void perf_event_free_filter(struct perf_event *event)
7103{
7104	ftrace_profile_free_filter(event);
7105}
7106
7107static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7108{
7109	struct bpf_prog *prog;
7110
7111	if (event->attr.type != PERF_TYPE_TRACEPOINT)
7112		return -EINVAL;
7113
7114	if (event->tp_event->prog)
7115		return -EEXIST;
7116
7117	if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7118		/* bpf programs can only be attached to u/kprobes */
7119		return -EINVAL;
7120
7121	prog = bpf_prog_get(prog_fd);
7122	if (IS_ERR(prog))
7123		return PTR_ERR(prog);
7124
7125	if (prog->type != BPF_PROG_TYPE_KPROBE) {
7126		/* valid fd, but invalid bpf program type */
7127		bpf_prog_put(prog);
7128		return -EINVAL;
7129	}
7130
7131	event->tp_event->prog = prog;
7132
7133	return 0;
7134}
7135
7136static void perf_event_free_bpf_prog(struct perf_event *event)
7137{
7138	struct bpf_prog *prog;
7139
7140	if (!event->tp_event)
7141		return;
7142
7143	prog = event->tp_event->prog;
7144	if (prog) {
7145		event->tp_event->prog = NULL;
7146		bpf_prog_put(prog);
7147	}
7148}
7149
7150#else
7151
7152static inline void perf_tp_register(void)
7153{
7154}
7155
7156static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7157{
7158	return -ENOENT;
7159}
7160
7161static void perf_event_free_filter(struct perf_event *event)
7162{
7163}
7164
7165static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7166{
7167	return -ENOENT;
7168}
7169
7170static void perf_event_free_bpf_prog(struct perf_event *event)
7171{
7172}
7173#endif /* CONFIG_EVENT_TRACING */
7174
7175#ifdef CONFIG_HAVE_HW_BREAKPOINT
7176void perf_bp_event(struct perf_event *bp, void *data)
7177{
7178	struct perf_sample_data sample;
7179	struct pt_regs *regs = data;
7180
7181	perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7182
7183	if (!bp->hw.state && !perf_exclude_event(bp, regs))
7184		perf_swevent_event(bp, 1, &sample, regs);
7185}
7186#endif
7187
7188/*
7189 * hrtimer based swevent callback
7190 */
7191
7192static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7193{
7194	enum hrtimer_restart ret = HRTIMER_RESTART;
7195	struct perf_sample_data data;
7196	struct pt_regs *regs;
7197	struct perf_event *event;
7198	u64 period;
7199
7200	event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7201
7202	if (event->state != PERF_EVENT_STATE_ACTIVE)
7203		return HRTIMER_NORESTART;
7204
7205	event->pmu->read(event);
7206
7207	perf_sample_data_init(&data, 0, event->hw.last_period);
 
7208	regs = get_irq_regs();
7209
7210	if (regs && !perf_exclude_event(event, regs)) {
7211		if (!(event->attr.exclude_idle && is_idle_task(current)))
7212			if (__perf_event_overflow(event, 1, &data, regs))
7213				ret = HRTIMER_NORESTART;
7214	}
7215
7216	period = max_t(u64, 10000, event->hw.sample_period);
7217	hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7218
7219	return ret;
7220}
7221
7222static void perf_swevent_start_hrtimer(struct perf_event *event)
7223{
7224	struct hw_perf_event *hwc = &event->hw;
7225	s64 period;
7226
7227	if (!is_sampling_event(event))
7228		return;
7229
7230	period = local64_read(&hwc->period_left);
7231	if (period) {
7232		if (period < 0)
7233			period = 10000;
7234
7235		local64_set(&hwc->period_left, 0);
7236	} else {
7237		period = max_t(u64, 10000, hwc->sample_period);
7238	}
7239	hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7240		      HRTIMER_MODE_REL_PINNED);
 
7241}
7242
7243static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7244{
7245	struct hw_perf_event *hwc = &event->hw;
7246
7247	if (is_sampling_event(event)) {
7248		ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7249		local64_set(&hwc->period_left, ktime_to_ns(remaining));
7250
7251		hrtimer_cancel(&hwc->hrtimer);
7252	}
7253}
7254
7255static void perf_swevent_init_hrtimer(struct perf_event *event)
7256{
7257	struct hw_perf_event *hwc = &event->hw;
7258
7259	if (!is_sampling_event(event))
7260		return;
7261
7262	hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7263	hwc->hrtimer.function = perf_swevent_hrtimer;
7264
7265	/*
7266	 * Since hrtimers have a fixed rate, we can do a static freq->period
7267	 * mapping and avoid the whole period adjust feedback stuff.
7268	 */
7269	if (event->attr.freq) {
7270		long freq = event->attr.sample_freq;
7271
7272		event->attr.sample_period = NSEC_PER_SEC / freq;
7273		hwc->sample_period = event->attr.sample_period;
7274		local64_set(&hwc->period_left, hwc->sample_period);
7275		hwc->last_period = hwc->sample_period;
7276		event->attr.freq = 0;
7277	}
7278}
7279
7280/*
7281 * Software event: cpu wall time clock
7282 */
7283
7284static void cpu_clock_event_update(struct perf_event *event)
7285{
7286	s64 prev;
7287	u64 now;
7288
7289	now = local_clock();
7290	prev = local64_xchg(&event->hw.prev_count, now);
7291	local64_add(now - prev, &event->count);
7292}
7293
7294static void cpu_clock_event_start(struct perf_event *event, int flags)
7295{
7296	local64_set(&event->hw.prev_count, local_clock());
7297	perf_swevent_start_hrtimer(event);
7298}
7299
7300static void cpu_clock_event_stop(struct perf_event *event, int flags)
7301{
7302	perf_swevent_cancel_hrtimer(event);
7303	cpu_clock_event_update(event);
7304}
7305
7306static int cpu_clock_event_add(struct perf_event *event, int flags)
7307{
7308	if (flags & PERF_EF_START)
7309		cpu_clock_event_start(event, flags);
7310	perf_event_update_userpage(event);
7311
7312	return 0;
7313}
7314
7315static void cpu_clock_event_del(struct perf_event *event, int flags)
7316{
7317	cpu_clock_event_stop(event, flags);
7318}
7319
7320static void cpu_clock_event_read(struct perf_event *event)
7321{
7322	cpu_clock_event_update(event);
7323}
7324
7325static int cpu_clock_event_init(struct perf_event *event)
7326{
7327	if (event->attr.type != PERF_TYPE_SOFTWARE)
7328		return -ENOENT;
7329
7330	if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7331		return -ENOENT;
7332
7333	/*
7334	 * no branch sampling for software events
7335	 */
7336	if (has_branch_stack(event))
7337		return -EOPNOTSUPP;
7338
7339	perf_swevent_init_hrtimer(event);
7340
7341	return 0;
7342}
7343
7344static struct pmu perf_cpu_clock = {
7345	.task_ctx_nr	= perf_sw_context,
7346
7347	.capabilities	= PERF_PMU_CAP_NO_NMI,
7348
7349	.event_init	= cpu_clock_event_init,
7350	.add		= cpu_clock_event_add,
7351	.del		= cpu_clock_event_del,
7352	.start		= cpu_clock_event_start,
7353	.stop		= cpu_clock_event_stop,
7354	.read		= cpu_clock_event_read,
7355};
7356
7357/*
7358 * Software event: task time clock
7359 */
7360
7361static void task_clock_event_update(struct perf_event *event, u64 now)
7362{
7363	u64 prev;
7364	s64 delta;
7365
7366	prev = local64_xchg(&event->hw.prev_count, now);
7367	delta = now - prev;
7368	local64_add(delta, &event->count);
7369}
7370
7371static void task_clock_event_start(struct perf_event *event, int flags)
7372{
7373	local64_set(&event->hw.prev_count, event->ctx->time);
7374	perf_swevent_start_hrtimer(event);
7375}
7376
7377static void task_clock_event_stop(struct perf_event *event, int flags)
7378{
7379	perf_swevent_cancel_hrtimer(event);
7380	task_clock_event_update(event, event->ctx->time);
7381}
7382
7383static int task_clock_event_add(struct perf_event *event, int flags)
7384{
7385	if (flags & PERF_EF_START)
7386		task_clock_event_start(event, flags);
7387	perf_event_update_userpage(event);
7388
7389	return 0;
7390}
7391
7392static void task_clock_event_del(struct perf_event *event, int flags)
7393{
7394	task_clock_event_stop(event, PERF_EF_UPDATE);
7395}
7396
7397static void task_clock_event_read(struct perf_event *event)
7398{
7399	u64 now = perf_clock();
7400	u64 delta = now - event->ctx->timestamp;
7401	u64 time = event->ctx->time + delta;
7402
7403	task_clock_event_update(event, time);
7404}
7405
7406static int task_clock_event_init(struct perf_event *event)
7407{
7408	if (event->attr.type != PERF_TYPE_SOFTWARE)
7409		return -ENOENT;
7410
7411	if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7412		return -ENOENT;
7413
7414	/*
7415	 * no branch sampling for software events
7416	 */
7417	if (has_branch_stack(event))
7418		return -EOPNOTSUPP;
7419
7420	perf_swevent_init_hrtimer(event);
7421
7422	return 0;
7423}
7424
7425static struct pmu perf_task_clock = {
7426	.task_ctx_nr	= perf_sw_context,
7427
7428	.capabilities	= PERF_PMU_CAP_NO_NMI,
7429
7430	.event_init	= task_clock_event_init,
7431	.add		= task_clock_event_add,
7432	.del		= task_clock_event_del,
7433	.start		= task_clock_event_start,
7434	.stop		= task_clock_event_stop,
7435	.read		= task_clock_event_read,
7436};
7437
7438static void perf_pmu_nop_void(struct pmu *pmu)
7439{
7440}
7441
7442static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7443{
7444}
7445
7446static int perf_pmu_nop_int(struct pmu *pmu)
7447{
7448	return 0;
7449}
7450
7451static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7452
7453static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7454{
7455	__this_cpu_write(nop_txn_flags, flags);
7456
7457	if (flags & ~PERF_PMU_TXN_ADD)
7458		return;
7459
7460	perf_pmu_disable(pmu);
7461}
7462
7463static int perf_pmu_commit_txn(struct pmu *pmu)
7464{
7465	unsigned int flags = __this_cpu_read(nop_txn_flags);
7466
7467	__this_cpu_write(nop_txn_flags, 0);
7468
7469	if (flags & ~PERF_PMU_TXN_ADD)
7470		return 0;
7471
7472	perf_pmu_enable(pmu);
7473	return 0;
7474}
7475
7476static void perf_pmu_cancel_txn(struct pmu *pmu)
7477{
7478	unsigned int flags =  __this_cpu_read(nop_txn_flags);
7479
7480	__this_cpu_write(nop_txn_flags, 0);
7481
7482	if (flags & ~PERF_PMU_TXN_ADD)
7483		return;
7484
7485	perf_pmu_enable(pmu);
7486}
7487
7488static int perf_event_idx_default(struct perf_event *event)
7489{
7490	return 0;
7491}
7492
7493/*
7494 * Ensures all contexts with the same task_ctx_nr have the same
7495 * pmu_cpu_context too.
7496 */
7497static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7498{
7499	struct pmu *pmu;
7500
7501	if (ctxn < 0)
7502		return NULL;
7503
7504	list_for_each_entry(pmu, &pmus, entry) {
7505		if (pmu->task_ctx_nr == ctxn)
7506			return pmu->pmu_cpu_context;
7507	}
7508
7509	return NULL;
7510}
7511
7512static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7513{
7514	int cpu;
7515
7516	for_each_possible_cpu(cpu) {
7517		struct perf_cpu_context *cpuctx;
7518
7519		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7520
7521		if (cpuctx->unique_pmu == old_pmu)
7522			cpuctx->unique_pmu = pmu;
7523	}
7524}
7525
7526static void free_pmu_context(struct pmu *pmu)
7527{
7528	struct pmu *i;
7529
7530	mutex_lock(&pmus_lock);
7531	/*
7532	 * Like a real lame refcount.
7533	 */
7534	list_for_each_entry(i, &pmus, entry) {
7535		if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7536			update_pmu_context(i, pmu);
7537			goto out;
7538		}
7539	}
7540
7541	free_percpu(pmu->pmu_cpu_context);
7542out:
7543	mutex_unlock(&pmus_lock);
7544}
7545static struct idr pmu_idr;
7546
7547static ssize_t
7548type_show(struct device *dev, struct device_attribute *attr, char *page)
7549{
7550	struct pmu *pmu = dev_get_drvdata(dev);
7551
7552	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7553}
7554static DEVICE_ATTR_RO(type);
7555
7556static ssize_t
7557perf_event_mux_interval_ms_show(struct device *dev,
7558				struct device_attribute *attr,
7559				char *page)
7560{
7561	struct pmu *pmu = dev_get_drvdata(dev);
7562
7563	return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7564}
7565
7566static DEFINE_MUTEX(mux_interval_mutex);
7567
7568static ssize_t
7569perf_event_mux_interval_ms_store(struct device *dev,
7570				 struct device_attribute *attr,
7571				 const char *buf, size_t count)
7572{
7573	struct pmu *pmu = dev_get_drvdata(dev);
7574	int timer, cpu, ret;
7575
7576	ret = kstrtoint(buf, 0, &timer);
7577	if (ret)
7578		return ret;
7579
7580	if (timer < 1)
7581		return -EINVAL;
7582
7583	/* same value, noting to do */
7584	if (timer == pmu->hrtimer_interval_ms)
7585		return count;
7586
7587	mutex_lock(&mux_interval_mutex);
7588	pmu->hrtimer_interval_ms = timer;
7589
7590	/* update all cpuctx for this PMU */
7591	get_online_cpus();
7592	for_each_online_cpu(cpu) {
7593		struct perf_cpu_context *cpuctx;
7594		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7595		cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7596
7597		cpu_function_call(cpu,
7598			(remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7599	}
7600	put_online_cpus();
7601	mutex_unlock(&mux_interval_mutex);
7602
7603	return count;
7604}
7605static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7606
7607static struct attribute *pmu_dev_attrs[] = {
7608	&dev_attr_type.attr,
7609	&dev_attr_perf_event_mux_interval_ms.attr,
7610	NULL,
7611};
7612ATTRIBUTE_GROUPS(pmu_dev);
7613
7614static int pmu_bus_running;
7615static struct bus_type pmu_bus = {
7616	.name		= "event_source",
7617	.dev_groups	= pmu_dev_groups,
7618};
7619
7620static void pmu_dev_release(struct device *dev)
7621{
7622	kfree(dev);
7623}
7624
7625static int pmu_dev_alloc(struct pmu *pmu)
7626{
7627	int ret = -ENOMEM;
7628
7629	pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7630	if (!pmu->dev)
7631		goto out;
7632
7633	pmu->dev->groups = pmu->attr_groups;
7634	device_initialize(pmu->dev);
7635	ret = dev_set_name(pmu->dev, "%s", pmu->name);
7636	if (ret)
7637		goto free_dev;
7638
7639	dev_set_drvdata(pmu->dev, pmu);
7640	pmu->dev->bus = &pmu_bus;
7641	pmu->dev->release = pmu_dev_release;
7642	ret = device_add(pmu->dev);
7643	if (ret)
7644		goto free_dev;
7645
7646out:
7647	return ret;
7648
7649free_dev:
7650	put_device(pmu->dev);
7651	goto out;
7652}
7653
7654static struct lock_class_key cpuctx_mutex;
7655static struct lock_class_key cpuctx_lock;
7656
7657int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7658{
7659	int cpu, ret;
7660
7661	mutex_lock(&pmus_lock);
7662	ret = -ENOMEM;
7663	pmu->pmu_disable_count = alloc_percpu(int);
7664	if (!pmu->pmu_disable_count)
7665		goto unlock;
7666
7667	pmu->type = -1;
7668	if (!name)
7669		goto skip_type;
7670	pmu->name = name;
7671
7672	if (type < 0) {
7673		type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7674		if (type < 0) {
7675			ret = type;
 
 
 
 
7676			goto free_pdc;
7677		}
7678	}
7679	pmu->type = type;
7680
7681	if (pmu_bus_running) {
7682		ret = pmu_dev_alloc(pmu);
7683		if (ret)
7684			goto free_idr;
7685	}
7686
7687skip_type:
7688	pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7689	if (pmu->pmu_cpu_context)
7690		goto got_cpu_context;
7691
7692	ret = -ENOMEM;
7693	pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7694	if (!pmu->pmu_cpu_context)
7695		goto free_dev;
7696
7697	for_each_possible_cpu(cpu) {
7698		struct perf_cpu_context *cpuctx;
7699
7700		cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7701		__perf_event_init_context(&cpuctx->ctx);
7702		lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7703		lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
 
7704		cpuctx->ctx.pmu = pmu;
7705
7706		__perf_mux_hrtimer_init(cpuctx, cpu);
7707
7708		cpuctx->unique_pmu = pmu;
7709	}
7710
7711got_cpu_context:
7712	if (!pmu->start_txn) {
7713		if (pmu->pmu_enable) {
7714			/*
7715			 * If we have pmu_enable/pmu_disable calls, install
7716			 * transaction stubs that use that to try and batch
7717			 * hardware accesses.
7718			 */
7719			pmu->start_txn  = perf_pmu_start_txn;
7720			pmu->commit_txn = perf_pmu_commit_txn;
7721			pmu->cancel_txn = perf_pmu_cancel_txn;
7722		} else {
7723			pmu->start_txn  = perf_pmu_nop_txn;
7724			pmu->commit_txn = perf_pmu_nop_int;
7725			pmu->cancel_txn = perf_pmu_nop_void;
7726		}
7727	}
7728
7729	if (!pmu->pmu_enable) {
7730		pmu->pmu_enable  = perf_pmu_nop_void;
7731		pmu->pmu_disable = perf_pmu_nop_void;
7732	}
7733
7734	if (!pmu->event_idx)
7735		pmu->event_idx = perf_event_idx_default;
7736
7737	list_add_rcu(&pmu->entry, &pmus);
7738	atomic_set(&pmu->exclusive_cnt, 0);
7739	ret = 0;
7740unlock:
7741	mutex_unlock(&pmus_lock);
7742
7743	return ret;
7744
7745free_dev:
7746	device_del(pmu->dev);
7747	put_device(pmu->dev);
7748
7749free_idr:
7750	if (pmu->type >= PERF_TYPE_MAX)
7751		idr_remove(&pmu_idr, pmu->type);
7752
7753free_pdc:
7754	free_percpu(pmu->pmu_disable_count);
7755	goto unlock;
7756}
7757EXPORT_SYMBOL_GPL(perf_pmu_register);
7758
7759void perf_pmu_unregister(struct pmu *pmu)
7760{
7761	mutex_lock(&pmus_lock);
7762	list_del_rcu(&pmu->entry);
7763	mutex_unlock(&pmus_lock);
7764
7765	/*
7766	 * We dereference the pmu list under both SRCU and regular RCU, so
7767	 * synchronize against both of those.
7768	 */
7769	synchronize_srcu(&pmus_srcu);
7770	synchronize_rcu();
7771
7772	free_percpu(pmu->pmu_disable_count);
7773	if (pmu->type >= PERF_TYPE_MAX)
7774		idr_remove(&pmu_idr, pmu->type);
7775	device_del(pmu->dev);
7776	put_device(pmu->dev);
7777	free_pmu_context(pmu);
7778}
7779EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7780
7781static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7782{
7783	struct perf_event_context *ctx = NULL;
7784	int ret;
7785
7786	if (!try_module_get(pmu->module))
7787		return -ENODEV;
7788
7789	if (event->group_leader != event) {
7790		/*
7791		 * This ctx->mutex can nest when we're called through
7792		 * inheritance. See the perf_event_ctx_lock_nested() comment.
7793		 */
7794		ctx = perf_event_ctx_lock_nested(event->group_leader,
7795						 SINGLE_DEPTH_NESTING);
7796		BUG_ON(!ctx);
7797	}
7798
7799	event->pmu = pmu;
7800	ret = pmu->event_init(event);
7801
7802	if (ctx)
7803		perf_event_ctx_unlock(event->group_leader, ctx);
7804
7805	if (ret)
7806		module_put(pmu->module);
7807
7808	return ret;
7809}
7810
7811static struct pmu *perf_init_event(struct perf_event *event)
7812{
7813	struct pmu *pmu = NULL;
7814	int idx;
7815	int ret;
7816
7817	idx = srcu_read_lock(&pmus_srcu);
7818
7819	rcu_read_lock();
7820	pmu = idr_find(&pmu_idr, event->attr.type);
7821	rcu_read_unlock();
7822	if (pmu) {
7823		ret = perf_try_init_event(pmu, event);
7824		if (ret)
7825			pmu = ERR_PTR(ret);
7826		goto unlock;
7827	}
7828
7829	list_for_each_entry_rcu(pmu, &pmus, entry) {
7830		ret = perf_try_init_event(pmu, event);
7831		if (!ret)
7832			goto unlock;
7833
7834		if (ret != -ENOENT) {
7835			pmu = ERR_PTR(ret);
7836			goto unlock;
7837		}
7838	}
7839	pmu = ERR_PTR(-ENOENT);
7840unlock:
7841	srcu_read_unlock(&pmus_srcu, idx);
7842
7843	return pmu;
7844}
7845
7846static void account_event_cpu(struct perf_event *event, int cpu)
7847{
7848	if (event->parent)
7849		return;
7850
7851	if (is_cgroup_event(event))
7852		atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7853}
7854
7855/* Freq events need the tick to stay alive (see perf_event_task_tick). */
7856static void account_freq_event_nohz(void)
7857{
7858#ifdef CONFIG_NO_HZ_FULL
7859	/* Lock so we don't race with concurrent unaccount */
7860	spin_lock(&nr_freq_lock);
7861	if (atomic_inc_return(&nr_freq_events) == 1)
7862		tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
7863	spin_unlock(&nr_freq_lock);
7864#endif
7865}
7866
7867static void account_freq_event(void)
7868{
7869	if (tick_nohz_full_enabled())
7870		account_freq_event_nohz();
7871	else
7872		atomic_inc(&nr_freq_events);
7873}
7874
7875
7876static void account_event(struct perf_event *event)
7877{
7878	bool inc = false;
7879
7880	if (event->parent)
7881		return;
7882
7883	if (event->attach_state & PERF_ATTACH_TASK)
7884		inc = true;
7885	if (event->attr.mmap || event->attr.mmap_data)
7886		atomic_inc(&nr_mmap_events);
7887	if (event->attr.comm)
7888		atomic_inc(&nr_comm_events);
7889	if (event->attr.task)
7890		atomic_inc(&nr_task_events);
7891	if (event->attr.freq)
7892		account_freq_event();
7893	if (event->attr.context_switch) {
7894		atomic_inc(&nr_switch_events);
7895		inc = true;
7896	}
7897	if (has_branch_stack(event))
7898		inc = true;
7899	if (is_cgroup_event(event))
7900		inc = true;
7901
7902	if (inc) {
7903		if (atomic_inc_not_zero(&perf_sched_count))
7904			goto enabled;
7905
7906		mutex_lock(&perf_sched_mutex);
7907		if (!atomic_read(&perf_sched_count)) {
7908			static_branch_enable(&perf_sched_events);
7909			/*
7910			 * Guarantee that all CPUs observe they key change and
7911			 * call the perf scheduling hooks before proceeding to
7912			 * install events that need them.
7913			 */
7914			synchronize_sched();
7915		}
7916		/*
7917		 * Now that we have waited for the sync_sched(), allow further
7918		 * increments to by-pass the mutex.
7919		 */
7920		atomic_inc(&perf_sched_count);
7921		mutex_unlock(&perf_sched_mutex);
7922	}
7923enabled:
7924
7925	account_event_cpu(event, event->cpu);
7926}
7927
7928/*
7929 * Allocate and initialize a event structure
7930 */
7931static struct perf_event *
7932perf_event_alloc(struct perf_event_attr *attr, int cpu,
7933		 struct task_struct *task,
7934		 struct perf_event *group_leader,
7935		 struct perf_event *parent_event,
7936		 perf_overflow_handler_t overflow_handler,
7937		 void *context, int cgroup_fd)
7938{
7939	struct pmu *pmu;
7940	struct perf_event *event;
7941	struct hw_perf_event *hwc;
7942	long err = -EINVAL;
7943
7944	if ((unsigned)cpu >= nr_cpu_ids) {
7945		if (!task || cpu != -1)
7946			return ERR_PTR(-EINVAL);
7947	}
7948
7949	event = kzalloc(sizeof(*event), GFP_KERNEL);
7950	if (!event)
7951		return ERR_PTR(-ENOMEM);
7952
7953	/*
7954	 * Single events are their own group leaders, with an
7955	 * empty sibling list:
7956	 */
7957	if (!group_leader)
7958		group_leader = event;
7959
7960	mutex_init(&event->child_mutex);
7961	INIT_LIST_HEAD(&event->child_list);
7962
7963	INIT_LIST_HEAD(&event->group_entry);
7964	INIT_LIST_HEAD(&event->event_entry);
7965	INIT_LIST_HEAD(&event->sibling_list);
7966	INIT_LIST_HEAD(&event->rb_entry);
7967	INIT_LIST_HEAD(&event->active_entry);
7968	INIT_HLIST_NODE(&event->hlist_entry);
7969
7970
7971	init_waitqueue_head(&event->waitq);
7972	init_irq_work(&event->pending, perf_pending_event);
7973
7974	mutex_init(&event->mmap_mutex);
7975
7976	atomic_long_set(&event->refcount, 1);
7977	event->cpu		= cpu;
7978	event->attr		= *attr;
7979	event->group_leader	= group_leader;
7980	event->pmu		= NULL;
7981	event->oncpu		= -1;
7982
7983	event->parent		= parent_event;
7984
7985	event->ns		= get_pid_ns(task_active_pid_ns(current));
7986	event->id		= atomic64_inc_return(&perf_event_id);
7987
7988	event->state		= PERF_EVENT_STATE_INACTIVE;
7989
7990	if (task) {
7991		event->attach_state = PERF_ATTACH_TASK;
 
7992		/*
7993		 * XXX pmu::event_init needs to know what task to account to
7994		 * and we cannot use the ctx information because we need the
7995		 * pmu before we get a ctx.
7996		 */
7997		event->hw.target = task;
 
 
7998	}
7999
8000	event->clock = &local_clock;
8001	if (parent_event)
8002		event->clock = parent_event->clock;
8003
8004	if (!overflow_handler && parent_event) {
8005		overflow_handler = parent_event->overflow_handler;
8006		context = parent_event->overflow_handler_context;
8007	}
8008
8009	event->overflow_handler	= overflow_handler;
8010	event->overflow_handler_context = context;
8011
8012	perf_event__state_init(event);
 
8013
8014	pmu = NULL;
8015
8016	hwc = &event->hw;
8017	hwc->sample_period = attr->sample_period;
8018	if (attr->freq && attr->sample_freq)
8019		hwc->sample_period = 1;
8020	hwc->last_period = hwc->sample_period;
8021
8022	local64_set(&hwc->period_left, hwc->sample_period);
8023
8024	/*
8025	 * we currently do not support PERF_FORMAT_GROUP on inherited events
8026	 */
8027	if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8028		goto err_ns;
8029
8030	if (!has_branch_stack(event))
8031		event->attr.branch_sample_type = 0;
8032
8033	if (cgroup_fd != -1) {
8034		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8035		if (err)
8036			goto err_ns;
8037	}
8038
8039	pmu = perf_init_event(event);
 
 
 
8040	if (!pmu)
8041		goto err_ns;
8042	else if (IS_ERR(pmu)) {
8043		err = PTR_ERR(pmu);
8044		goto err_ns;
 
 
 
 
 
8045	}
8046
8047	err = exclusive_event_init(event);
8048	if (err)
8049		goto err_pmu;
8050
8051	if (!event->parent) {
 
 
 
 
 
 
 
 
8052		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8053			err = get_callchain_buffers();
8054			if (err)
8055				goto err_per_task;
 
 
8056		}
8057	}
8058
8059	/* symmetric to unaccount_event() in _free_event() */
8060	account_event(event);
8061
8062	return event;
8063
8064err_per_task:
8065	exclusive_event_destroy(event);
8066
8067err_pmu:
8068	if (event->destroy)
8069		event->destroy(event);
8070	module_put(pmu->module);
8071err_ns:
8072	if (is_cgroup_event(event))
8073		perf_detach_cgroup(event);
8074	if (event->ns)
8075		put_pid_ns(event->ns);
8076	kfree(event);
8077
8078	return ERR_PTR(err);
8079}
8080
8081static int perf_copy_attr(struct perf_event_attr __user *uattr,
8082			  struct perf_event_attr *attr)
8083{
8084	u32 size;
8085	int ret;
8086
8087	if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8088		return -EFAULT;
8089
8090	/*
8091	 * zero the full structure, so that a short copy will be nice.
8092	 */
8093	memset(attr, 0, sizeof(*attr));
8094
8095	ret = get_user(size, &uattr->size);
8096	if (ret)
8097		return ret;
8098
8099	if (size > PAGE_SIZE)	/* silly large */
8100		goto err_size;
8101
8102	if (!size)		/* abi compat */
8103		size = PERF_ATTR_SIZE_VER0;
8104
8105	if (size < PERF_ATTR_SIZE_VER0)
8106		goto err_size;
8107
8108	/*
8109	 * If we're handed a bigger struct than we know of,
8110	 * ensure all the unknown bits are 0 - i.e. new
8111	 * user-space does not rely on any kernel feature
8112	 * extensions we dont know about yet.
8113	 */
8114	if (size > sizeof(*attr)) {
8115		unsigned char __user *addr;
8116		unsigned char __user *end;
8117		unsigned char val;
8118
8119		addr = (void __user *)uattr + sizeof(*attr);
8120		end  = (void __user *)uattr + size;
8121
8122		for (; addr < end; addr++) {
8123			ret = get_user(val, addr);
8124			if (ret)
8125				return ret;
8126			if (val)
8127				goto err_size;
8128		}
8129		size = sizeof(*attr);
8130	}
8131
8132	ret = copy_from_user(attr, uattr, size);
8133	if (ret)
8134		return -EFAULT;
8135
8136	if (attr->__reserved_1)
8137		return -EINVAL;
8138
8139	if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8140		return -EINVAL;
8141
8142	if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8143		return -EINVAL;
8144
8145	if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8146		u64 mask = attr->branch_sample_type;
8147
8148		/* only using defined bits */
8149		if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8150			return -EINVAL;
8151
8152		/* at least one branch bit must be set */
8153		if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8154			return -EINVAL;
8155
8156		/* propagate priv level, when not set for branch */
8157		if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8158
8159			/* exclude_kernel checked on syscall entry */
8160			if (!attr->exclude_kernel)
8161				mask |= PERF_SAMPLE_BRANCH_KERNEL;
8162
8163			if (!attr->exclude_user)
8164				mask |= PERF_SAMPLE_BRANCH_USER;
8165
8166			if (!attr->exclude_hv)
8167				mask |= PERF_SAMPLE_BRANCH_HV;
8168			/*
8169			 * adjust user setting (for HW filter setup)
8170			 */
8171			attr->branch_sample_type = mask;
8172		}
8173		/* privileged levels capture (kernel, hv): check permissions */
8174		if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8175		    && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8176			return -EACCES;
8177	}
8178
8179	if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8180		ret = perf_reg_validate(attr->sample_regs_user);
8181		if (ret)
8182			return ret;
8183	}
8184
8185	if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8186		if (!arch_perf_have_user_stack_dump())
8187			return -ENOSYS;
8188
8189		/*
8190		 * We have __u32 type for the size, but so far
8191		 * we can only use __u16 as maximum due to the
8192		 * __u16 sample size limit.
8193		 */
8194		if (attr->sample_stack_user >= USHRT_MAX)
8195			ret = -EINVAL;
8196		else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8197			ret = -EINVAL;
8198	}
8199
8200	if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8201		ret = perf_reg_validate(attr->sample_regs_intr);
8202out:
8203	return ret;
8204
8205err_size:
8206	put_user(sizeof(*attr), &uattr->size);
8207	ret = -E2BIG;
8208	goto out;
8209}
8210
8211static int
8212perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8213{
8214	struct ring_buffer *rb = NULL;
8215	int ret = -EINVAL;
8216
8217	if (!output_event)
8218		goto set;
8219
8220	/* don't allow circular references */
8221	if (event == output_event)
8222		goto out;
8223
8224	/*
8225	 * Don't allow cross-cpu buffers
8226	 */
8227	if (output_event->cpu != event->cpu)
8228		goto out;
8229
8230	/*
8231	 * If its not a per-cpu rb, it must be the same task.
8232	 */
8233	if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8234		goto out;
8235
8236	/*
8237	 * Mixing clocks in the same buffer is trouble you don't need.
8238	 */
8239	if (output_event->clock != event->clock)
8240		goto out;
8241
8242	/*
8243	 * If both events generate aux data, they must be on the same PMU
8244	 */
8245	if (has_aux(event) && has_aux(output_event) &&
8246	    event->pmu != output_event->pmu)
8247		goto out;
8248
8249set:
8250	mutex_lock(&event->mmap_mutex);
8251	/* Can't redirect output if we've got an active mmap() */
8252	if (atomic_read(&event->mmap_count))
8253		goto unlock;
8254
8255	if (output_event) {
8256		/* get the rb we want to redirect to */
8257		rb = ring_buffer_get(output_event);
8258		if (!rb)
8259			goto unlock;
8260	}
8261
8262	ring_buffer_attach(event, rb);
8263
8264	ret = 0;
8265unlock:
8266	mutex_unlock(&event->mmap_mutex);
8267
 
 
8268out:
8269	return ret;
8270}
8271
8272static void mutex_lock_double(struct mutex *a, struct mutex *b)
8273{
8274	if (b < a)
8275		swap(a, b);
8276
8277	mutex_lock(a);
8278	mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8279}
8280
8281static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8282{
8283	bool nmi_safe = false;
8284
8285	switch (clk_id) {
8286	case CLOCK_MONOTONIC:
8287		event->clock = &ktime_get_mono_fast_ns;
8288		nmi_safe = true;
8289		break;
8290
8291	case CLOCK_MONOTONIC_RAW:
8292		event->clock = &ktime_get_raw_fast_ns;
8293		nmi_safe = true;
8294		break;
8295
8296	case CLOCK_REALTIME:
8297		event->clock = &ktime_get_real_ns;
8298		break;
8299
8300	case CLOCK_BOOTTIME:
8301		event->clock = &ktime_get_boot_ns;
8302		break;
8303
8304	case CLOCK_TAI:
8305		event->clock = &ktime_get_tai_ns;
8306		break;
8307
8308	default:
8309		return -EINVAL;
8310	}
8311
8312	if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8313		return -EINVAL;
8314
8315	return 0;
8316}
8317
8318/**
8319 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8320 *
8321 * @attr_uptr:	event_id type attributes for monitoring/sampling
8322 * @pid:		target pid
8323 * @cpu:		target cpu
8324 * @group_fd:		group leader event fd
8325 */
8326SYSCALL_DEFINE5(perf_event_open,
8327		struct perf_event_attr __user *, attr_uptr,
8328		pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8329{
8330	struct perf_event *group_leader = NULL, *output_event = NULL;
8331	struct perf_event *event, *sibling;
8332	struct perf_event_attr attr;
8333	struct perf_event_context *ctx, *uninitialized_var(gctx);
8334	struct file *event_file = NULL;
8335	struct fd group = {NULL, 0};
8336	struct task_struct *task = NULL;
8337	struct pmu *pmu;
8338	int event_fd;
8339	int move_group = 0;
 
8340	int err;
8341	int f_flags = O_RDWR;
8342	int cgroup_fd = -1;
8343
8344	/* for future expandability... */
8345	if (flags & ~PERF_FLAG_ALL)
8346		return -EINVAL;
8347
8348	err = perf_copy_attr(attr_uptr, &attr);
8349	if (err)
8350		return err;
8351
8352	if (!attr.exclude_kernel) {
8353		if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8354			return -EACCES;
8355	}
8356
8357	if (attr.freq) {
8358		if (attr.sample_freq > sysctl_perf_event_sample_rate)
8359			return -EINVAL;
8360	} else {
8361		if (attr.sample_period & (1ULL << 63))
8362			return -EINVAL;
8363	}
8364
8365	/*
8366	 * In cgroup mode, the pid argument is used to pass the fd
8367	 * opened to the cgroup directory in cgroupfs. The cpu argument
8368	 * designates the cpu on which to monitor threads from that
8369	 * cgroup.
8370	 */
8371	if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8372		return -EINVAL;
8373
8374	if (flags & PERF_FLAG_FD_CLOEXEC)
8375		f_flags |= O_CLOEXEC;
8376
8377	event_fd = get_unused_fd_flags(f_flags);
8378	if (event_fd < 0)
8379		return event_fd;
8380
8381	if (group_fd != -1) {
8382		err = perf_fget_light(group_fd, &group);
8383		if (err)
 
8384			goto err_fd;
8385		group_leader = group.file->private_data;
 
8386		if (flags & PERF_FLAG_FD_OUTPUT)
8387			output_event = group_leader;
8388		if (flags & PERF_FLAG_FD_NO_GROUP)
8389			group_leader = NULL;
8390	}
8391
8392	if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8393		task = find_lively_task_by_vpid(pid);
8394		if (IS_ERR(task)) {
8395			err = PTR_ERR(task);
8396			goto err_group_fd;
8397		}
8398	}
8399
8400	if (task && group_leader &&
8401	    group_leader->attr.inherit != attr.inherit) {
8402		err = -EINVAL;
8403		goto err_task;
8404	}
8405
8406	get_online_cpus();
8407
8408	if (task) {
8409		err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
8410		if (err)
8411			goto err_cpus;
8412
8413		/*
8414		 * Reuse ptrace permission checks for now.
8415		 *
8416		 * We must hold cred_guard_mutex across this and any potential
8417		 * perf_install_in_context() call for this new event to
8418		 * serialize against exec() altering our credentials (and the
8419		 * perf_event_exit_task() that could imply).
8420		 */
8421		err = -EACCES;
8422		if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
8423			goto err_cred;
8424	}
8425
8426	if (flags & PERF_FLAG_PID_CGROUP)
8427		cgroup_fd = pid;
8428
8429	event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8430				 NULL, NULL, cgroup_fd);
8431	if (IS_ERR(event)) {
8432		err = PTR_ERR(event);
8433		goto err_cred;
8434	}
8435
8436	if (is_sampling_event(event)) {
8437		if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8438			err = -ENOTSUPP;
8439			goto err_alloc;
8440		}
 
 
 
 
 
 
8441	}
8442
8443	/*
8444	 * Special case software events and allow them to be part of
8445	 * any hardware group.
8446	 */
8447	pmu = event->pmu;
8448
8449	if (attr.use_clockid) {
8450		err = perf_event_set_clock(event, attr.clockid);
8451		if (err)
8452			goto err_alloc;
8453	}
8454
8455	if (group_leader &&
8456	    (is_software_event(event) != is_software_event(group_leader))) {
8457		if (is_software_event(event)) {
8458			/*
8459			 * If event and group_leader are not both a software
8460			 * event, and event is, then group leader is not.
8461			 *
8462			 * Allow the addition of software events to !software
8463			 * groups, this is safe because software events never
8464			 * fail to schedule.
8465			 */
8466			pmu = group_leader->pmu;
8467		} else if (is_software_event(group_leader) &&
8468			   (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8469			/*
8470			 * In case the group is a pure software group, and we
8471			 * try to add a hardware event, move the whole group to
8472			 * the hardware context.
8473			 */
8474			move_group = 1;
8475		}
8476	}
8477
8478	/*
8479	 * Get the target context (task or percpu):
8480	 */
8481	ctx = find_get_context(pmu, task, event);
8482	if (IS_ERR(ctx)) {
8483		err = PTR_ERR(ctx);
8484		goto err_alloc;
8485	}
8486
8487	if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8488		err = -EBUSY;
8489		goto err_context;
8490	}
8491
8492	/*
8493	 * Look up the group leader (we will attach this event to it):
8494	 */
8495	if (group_leader) {
8496		err = -EINVAL;
8497
8498		/*
8499		 * Do not allow a recursive hierarchy (this new sibling
8500		 * becoming part of another group-sibling):
8501		 */
8502		if (group_leader->group_leader != group_leader)
8503			goto err_context;
8504
8505		/* All events in a group should have the same clock */
8506		if (group_leader->clock != event->clock)
8507			goto err_context;
8508
8509		/*
8510		 * Do not allow to attach to a group in a different
8511		 * task or CPU context:
8512		 */
8513		if (move_group) {
8514			/*
8515			 * Make sure we're both on the same task, or both
8516			 * per-cpu events.
8517			 */
8518			if (group_leader->ctx->task != ctx->task)
8519				goto err_context;
8520
8521			/*
8522			 * Make sure we're both events for the same CPU;
8523			 * grouping events for different CPUs is broken; since
8524			 * you can never concurrently schedule them anyhow.
8525			 */
8526			if (group_leader->cpu != event->cpu)
8527				goto err_context;
8528		} else {
8529			if (group_leader->ctx != ctx)
8530				goto err_context;
8531		}
8532
8533		/*
8534		 * Only a group leader can be exclusive or pinned
8535		 */
8536		if (attr.exclusive || attr.pinned)
8537			goto err_context;
8538	}
8539
8540	if (output_event) {
8541		err = perf_event_set_output(event, output_event);
8542		if (err)
8543			goto err_context;
8544	}
8545
8546	event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8547					f_flags);
8548	if (IS_ERR(event_file)) {
8549		err = PTR_ERR(event_file);
8550		event_file = NULL;
8551		goto err_context;
8552	}
8553
8554	if (move_group) {
8555		gctx = group_leader->ctx;
8556		mutex_lock_double(&gctx->mutex, &ctx->mutex);
8557		if (gctx->task == TASK_TOMBSTONE) {
8558			err = -ESRCH;
8559			goto err_locked;
8560		}
8561	} else {
8562		mutex_lock(&ctx->mutex);
8563	}
8564
8565	if (ctx->task == TASK_TOMBSTONE) {
8566		err = -ESRCH;
8567		goto err_locked;
8568	}
8569
8570	if (!perf_event_validate_size(event)) {
8571		err = -E2BIG;
8572		goto err_locked;
8573	}
8574
8575	/*
8576	 * Must be under the same ctx::mutex as perf_install_in_context(),
8577	 * because we need to serialize with concurrent event creation.
8578	 */
8579	if (!exclusive_event_installable(event, ctx)) {
8580		/* exclusive and group stuff are assumed mutually exclusive */
8581		WARN_ON_ONCE(move_group);
8582
8583		err = -EBUSY;
8584		goto err_locked;
8585	}
8586
8587	WARN_ON_ONCE(ctx->parent_ctx);
8588
8589	/*
8590	 * This is the point on no return; we cannot fail hereafter. This is
8591	 * where we start modifying current state.
8592	 */
8593
8594	if (move_group) {
8595		/*
8596		 * See perf_event_ctx_lock() for comments on the details
8597		 * of swizzling perf_event::ctx.
8598		 */
8599		perf_remove_from_context(group_leader, 0);
8600
 
 
8601		list_for_each_entry(sibling, &group_leader->sibling_list,
8602				    group_entry) {
8603			perf_remove_from_context(sibling, 0);
8604			put_ctx(gctx);
8605		}
 
 
 
8606
8607		/*
8608		 * Wait for everybody to stop referencing the events through
8609		 * the old lists, before installing it on new lists.
8610		 */
8611		synchronize_rcu();
8612
8613		/*
8614		 * Install the group siblings before the group leader.
8615		 *
8616		 * Because a group leader will try and install the entire group
8617		 * (through the sibling list, which is still in-tact), we can
8618		 * end up with siblings installed in the wrong context.
8619		 *
8620		 * By installing siblings first we NO-OP because they're not
8621		 * reachable through the group lists.
8622		 */
8623		list_for_each_entry(sibling, &group_leader->sibling_list,
8624				    group_entry) {
8625			perf_event__state_init(sibling);
8626			perf_install_in_context(ctx, sibling, sibling->cpu);
8627			get_ctx(ctx);
8628		}
8629
8630		/*
8631		 * Removing from the context ends up with disabled
8632		 * event. What we want here is event in the initial
8633		 * startup state, ready to be add into new context.
8634		 */
8635		perf_event__state_init(group_leader);
8636		perf_install_in_context(ctx, group_leader, group_leader->cpu);
8637		get_ctx(ctx);
8638
8639		/*
8640		 * Now that all events are installed in @ctx, nothing
8641		 * references @gctx anymore, so drop the last reference we have
8642		 * on it.
8643		 */
8644		put_ctx(gctx);
8645	}
8646
8647	/*
8648	 * Precalculate sample_data sizes; do while holding ctx::mutex such
8649	 * that we're serialized against further additions and before
8650	 * perf_install_in_context() which is the point the event is active and
8651	 * can use these values.
8652	 */
8653	perf_event__header_size(event);
8654	perf_event__id_header_size(event);
8655
8656	event->owner = current;
8657
8658	perf_install_in_context(ctx, event, event->cpu);
8659	perf_unpin_context(ctx);
8660
8661	if (move_group)
8662		mutex_unlock(&gctx->mutex);
8663	mutex_unlock(&ctx->mutex);
8664
8665	if (task) {
8666		mutex_unlock(&task->signal->cred_guard_mutex);
8667		put_task_struct(task);
8668	}
8669
8670	put_online_cpus();
8671
8672	mutex_lock(&current->perf_event_mutex);
8673	list_add_tail(&event->owner_entry, &current->perf_event_list);
8674	mutex_unlock(&current->perf_event_mutex);
8675
8676	/*
 
 
 
 
 
 
8677	 * Drop the reference on the group_event after placing the
8678	 * new event on the sibling_list. This ensures destruction
8679	 * of the group leader will find the pointer to itself in
8680	 * perf_group_detach().
8681	 */
8682	fdput(group);
8683	fd_install(event_fd, event_file);
8684	return event_fd;
8685
8686err_locked:
8687	if (move_group)
8688		mutex_unlock(&gctx->mutex);
8689	mutex_unlock(&ctx->mutex);
8690/* err_file: */
8691	fput(event_file);
8692err_context:
8693	perf_unpin_context(ctx);
8694	put_ctx(ctx);
8695err_alloc:
8696	/*
8697	 * If event_file is set, the fput() above will have called ->release()
8698	 * and that will take care of freeing the event.
8699	 */
8700	if (!event_file)
8701		free_event(event);
8702err_cred:
8703	if (task)
8704		mutex_unlock(&task->signal->cred_guard_mutex);
8705err_cpus:
8706	put_online_cpus();
8707err_task:
8708	if (task)
8709		put_task_struct(task);
8710err_group_fd:
8711	fdput(group);
8712err_fd:
8713	put_unused_fd(event_fd);
8714	return err;
8715}
8716
8717/**
8718 * perf_event_create_kernel_counter
8719 *
8720 * @attr: attributes of the counter to create
8721 * @cpu: cpu in which the counter is bound
8722 * @task: task to profile (NULL for percpu)
8723 */
8724struct perf_event *
8725perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8726				 struct task_struct *task,
8727				 perf_overflow_handler_t overflow_handler,
8728				 void *context)
8729{
8730	struct perf_event_context *ctx;
8731	struct perf_event *event;
8732	int err;
8733
8734	/*
8735	 * Get the target context (task or percpu):
8736	 */
8737
8738	event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8739				 overflow_handler, context, -1);
8740	if (IS_ERR(event)) {
8741		err = PTR_ERR(event);
8742		goto err;
8743	}
8744
8745	/* Mark owner so we could distinguish it from user events. */
8746	event->owner = TASK_TOMBSTONE;
8747
8748	ctx = find_get_context(event->pmu, task, event);
8749	if (IS_ERR(ctx)) {
8750		err = PTR_ERR(ctx);
8751		goto err_free;
8752	}
8753
 
8754	WARN_ON_ONCE(ctx->parent_ctx);
8755	mutex_lock(&ctx->mutex);
8756	if (ctx->task == TASK_TOMBSTONE) {
8757		err = -ESRCH;
8758		goto err_unlock;
8759	}
8760
8761	if (!exclusive_event_installable(event, ctx)) {
8762		err = -EBUSY;
8763		goto err_unlock;
8764	}
8765
8766	perf_install_in_context(ctx, event, cpu);
 
8767	perf_unpin_context(ctx);
8768	mutex_unlock(&ctx->mutex);
8769
8770	return event;
8771
8772err_unlock:
8773	mutex_unlock(&ctx->mutex);
8774	perf_unpin_context(ctx);
8775	put_ctx(ctx);
8776err_free:
8777	free_event(event);
8778err:
8779	return ERR_PTR(err);
8780}
8781EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8782
8783void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8784{
8785	struct perf_event_context *src_ctx;
8786	struct perf_event_context *dst_ctx;
8787	struct perf_event *event, *tmp;
8788	LIST_HEAD(events);
8789
8790	src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8791	dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8792
8793	/*
8794	 * See perf_event_ctx_lock() for comments on the details
8795	 * of swizzling perf_event::ctx.
8796	 */
8797	mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8798	list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8799				 event_entry) {
8800		perf_remove_from_context(event, 0);
8801		unaccount_event_cpu(event, src_cpu);
8802		put_ctx(src_ctx);
8803		list_add(&event->migrate_entry, &events);
8804	}
8805
8806	/*
8807	 * Wait for the events to quiesce before re-instating them.
8808	 */
8809	synchronize_rcu();
8810
8811	/*
8812	 * Re-instate events in 2 passes.
8813	 *
8814	 * Skip over group leaders and only install siblings on this first
8815	 * pass, siblings will not get enabled without a leader, however a
8816	 * leader will enable its siblings, even if those are still on the old
8817	 * context.
8818	 */
8819	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8820		if (event->group_leader == event)
8821			continue;
8822
8823		list_del(&event->migrate_entry);
8824		if (event->state >= PERF_EVENT_STATE_OFF)
8825			event->state = PERF_EVENT_STATE_INACTIVE;
8826		account_event_cpu(event, dst_cpu);
8827		perf_install_in_context(dst_ctx, event, dst_cpu);
8828		get_ctx(dst_ctx);
8829	}
8830
8831	/*
8832	 * Once all the siblings are setup properly, install the group leaders
8833	 * to make it go.
8834	 */
8835	list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8836		list_del(&event->migrate_entry);
8837		if (event->state >= PERF_EVENT_STATE_OFF)
8838			event->state = PERF_EVENT_STATE_INACTIVE;
8839		account_event_cpu(event, dst_cpu);
8840		perf_install_in_context(dst_ctx, event, dst_cpu);
8841		get_ctx(dst_ctx);
8842	}
8843	mutex_unlock(&dst_ctx->mutex);
8844	mutex_unlock(&src_ctx->mutex);
8845}
8846EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8847
8848static void sync_child_event(struct perf_event *child_event,
8849			       struct task_struct *child)
8850{
8851	struct perf_event *parent_event = child_event->parent;
8852	u64 child_val;
8853
8854	if (child_event->attr.inherit_stat)
8855		perf_event_read_event(child_event, child);
8856
8857	child_val = perf_event_count(child_event);
8858
8859	/*
8860	 * Add back the child's count to the parent's count:
8861	 */
8862	atomic64_add(child_val, &parent_event->child_count);
8863	atomic64_add(child_event->total_time_enabled,
8864		     &parent_event->child_total_time_enabled);
8865	atomic64_add(child_event->total_time_running,
8866		     &parent_event->child_total_time_running);
8867}
8868
8869static void
8870perf_event_exit_event(struct perf_event *child_event,
8871		      struct perf_event_context *child_ctx,
8872		      struct task_struct *child)
8873{
8874	struct perf_event *parent_event = child_event->parent;
8875
8876	/*
8877	 * Do not destroy the 'original' grouping; because of the context
8878	 * switch optimization the original events could've ended up in a
8879	 * random child task.
8880	 *
8881	 * If we were to destroy the original group, all group related
8882	 * operations would cease to function properly after this random
8883	 * child dies.
8884	 *
8885	 * Do destroy all inherited groups, we don't care about those
8886	 * and being thorough is better.
8887	 */
8888	raw_spin_lock_irq(&child_ctx->lock);
8889	WARN_ON_ONCE(child_ctx->is_active);
8890
8891	if (parent_event)
8892		perf_group_detach(child_event);
8893	list_del_event(child_event, child_ctx);
8894	child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
8895	raw_spin_unlock_irq(&child_ctx->lock);
8896
8897	/*
8898	 * Parent events are governed by their filedesc, retain them.
8899	 */
8900	if (!parent_event) {
8901		perf_event_wakeup(child_event);
8902		return;
8903	}
8904	/*
8905	 * Child events can be cleaned up.
8906	 */
8907
8908	sync_child_event(child_event, child);
8909
8910	/*
8911	 * Remove this event from the parent's list
8912	 */
8913	WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8914	mutex_lock(&parent_event->child_mutex);
8915	list_del_init(&child_event->child_list);
8916	mutex_unlock(&parent_event->child_mutex);
8917
8918	/*
8919	 * Kick perf_poll() for is_event_hup().
 
8920	 */
8921	perf_event_wakeup(parent_event);
8922	free_event(child_event);
8923	put_event(parent_event);
8924}
8925
8926static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
 
 
 
8927{
8928	struct perf_event_context *child_ctx, *clone_ctx = NULL;
8929	struct perf_event *child_event, *next;
 
 
 
8930
8931	WARN_ON_ONCE(child != current);
8932
8933	child_ctx = perf_pin_task_context(child, ctxn);
8934	if (!child_ctx)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8935		return;
 
8936
 
8937	/*
8938	 * In order to reduce the amount of tricky in ctx tear-down, we hold
8939	 * ctx::mutex over the entire thing. This serializes against almost
8940	 * everything that wants to access the ctx.
8941	 *
8942	 * The exception is sys_perf_event_open() /
8943	 * perf_event_create_kernel_count() which does find_get_context()
8944	 * without ctx::mutex (it cannot because of the move_group double mutex
8945	 * lock thing). See the comments in perf_install_in_context().
8946	 */
8947	mutex_lock(&child_ctx->mutex);
8948
8949	/*
8950	 * In a single ctx::lock section, de-schedule the events and detach the
8951	 * context from the task such that we cannot ever get it scheduled back
8952	 * in.
8953	 */
8954	raw_spin_lock_irq(&child_ctx->lock);
8955	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8956
8957	/*
8958	 * Now that the context is inactive, destroy the task <-> ctx relation
8959	 * and mark the context dead.
 
8960	 */
8961	RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8962	put_ctx(child_ctx); /* cannot be last */
8963	WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8964	put_task_struct(current); /* cannot be last */
8965
8966	clone_ctx = unclone_ctx(child_ctx);
8967	raw_spin_unlock_irq(&child_ctx->lock);
8968
8969	if (clone_ctx)
8970		put_ctx(clone_ctx);
8971
8972	/*
8973	 * Report the task dead after unscheduling the events so that we
8974	 * won't get any samples after PERF_RECORD_EXIT. We can however still
8975	 * get a few PERF_RECORD_READ events.
8976	 */
8977	perf_event_task(child, child_ctx, 0);
8978
8979	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8980		perf_event_exit_event(child_event, child_ctx, child);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8981
8982	mutex_unlock(&child_ctx->mutex);
8983
8984	put_ctx(child_ctx);
8985}
8986
8987/*
8988 * When a child task exits, feed back event values to parent events.
8989 *
8990 * Can be called with cred_guard_mutex held when called from
8991 * install_exec_creds().
8992 */
8993void perf_event_exit_task(struct task_struct *child)
8994{
8995	struct perf_event *event, *tmp;
8996	int ctxn;
8997
8998	mutex_lock(&child->perf_event_mutex);
8999	list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9000				 owner_entry) {
9001		list_del_init(&event->owner_entry);
9002
9003		/*
9004		 * Ensure the list deletion is visible before we clear
9005		 * the owner, closes a race against perf_release() where
9006		 * we need to serialize on the owner->perf_event_mutex.
9007		 */
9008		smp_store_release(&event->owner, NULL);
 
9009	}
9010	mutex_unlock(&child->perf_event_mutex);
9011
9012	for_each_task_context_nr(ctxn)
9013		perf_event_exit_task_context(child, ctxn);
9014
9015	/*
9016	 * The perf_event_exit_task_context calls perf_event_task
9017	 * with child's task_ctx, which generates EXIT events for
9018	 * child contexts and sets child->perf_event_ctxp[] to NULL.
9019	 * At this point we need to send EXIT events to cpu contexts.
9020	 */
9021	perf_event_task(child, NULL, 0);
9022}
9023
9024static void perf_free_event(struct perf_event *event,
9025			    struct perf_event_context *ctx)
9026{
9027	struct perf_event *parent = event->parent;
9028
9029	if (WARN_ON_ONCE(!parent))
9030		return;
9031
9032	mutex_lock(&parent->child_mutex);
9033	list_del_init(&event->child_list);
9034	mutex_unlock(&parent->child_mutex);
9035
9036	put_event(parent);
9037
9038	raw_spin_lock_irq(&ctx->lock);
9039	perf_group_detach(event);
9040	list_del_event(event, ctx);
9041	raw_spin_unlock_irq(&ctx->lock);
9042	free_event(event);
9043}
9044
9045/*
9046 * Free an unexposed, unused context as created by inheritance by
9047 * perf_event_init_task below, used by fork() in case of fail.
9048 *
9049 * Not all locks are strictly required, but take them anyway to be nice and
9050 * help out with the lockdep assertions.
9051 */
9052void perf_event_free_task(struct task_struct *task)
9053{
9054	struct perf_event_context *ctx;
9055	struct perf_event *event, *tmp;
9056	int ctxn;
9057
9058	for_each_task_context_nr(ctxn) {
9059		ctx = task->perf_event_ctxp[ctxn];
9060		if (!ctx)
9061			continue;
9062
9063		mutex_lock(&ctx->mutex);
9064again:
9065		list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9066				group_entry)
9067			perf_free_event(event, ctx);
9068
9069		list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9070				group_entry)
9071			perf_free_event(event, ctx);
9072
9073		if (!list_empty(&ctx->pinned_groups) ||
9074				!list_empty(&ctx->flexible_groups))
9075			goto again;
9076
9077		mutex_unlock(&ctx->mutex);
9078
9079		put_ctx(ctx);
9080	}
9081}
9082
9083void perf_event_delayed_put(struct task_struct *task)
9084{
9085	int ctxn;
9086
9087	for_each_task_context_nr(ctxn)
9088		WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9089}
9090
9091struct file *perf_event_get(unsigned int fd)
9092{
9093	struct file *file;
9094
9095	file = fget_raw(fd);
9096	if (!file)
9097		return ERR_PTR(-EBADF);
9098
9099	if (file->f_op != &perf_fops) {
9100		fput(file);
9101		return ERR_PTR(-EBADF);
9102	}
9103
9104	return file;
9105}
9106
9107const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9108{
9109	if (!event)
9110		return ERR_PTR(-EINVAL);
9111
9112	return &event->attr;
9113}
9114
9115/*
9116 * inherit a event from parent task to child task:
9117 */
9118static struct perf_event *
9119inherit_event(struct perf_event *parent_event,
9120	      struct task_struct *parent,
9121	      struct perf_event_context *parent_ctx,
9122	      struct task_struct *child,
9123	      struct perf_event *group_leader,
9124	      struct perf_event_context *child_ctx)
9125{
9126	enum perf_event_active_state parent_state = parent_event->state;
9127	struct perf_event *child_event;
9128	unsigned long flags;
9129
9130	/*
9131	 * Instead of creating recursive hierarchies of events,
9132	 * we link inherited events back to the original parent,
9133	 * which has a filp for sure, which we use as the reference
9134	 * count:
9135	 */
9136	if (parent_event->parent)
9137		parent_event = parent_event->parent;
9138
9139	child_event = perf_event_alloc(&parent_event->attr,
9140					   parent_event->cpu,
9141					   child,
9142					   group_leader, parent_event,
9143					   NULL, NULL, -1);
9144	if (IS_ERR(child_event))
9145		return child_event;
9146
9147	/*
9148	 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
9149	 * must be under the same lock in order to serialize against
9150	 * perf_event_release_kernel(), such that either we must observe
9151	 * is_orphaned_event() or they will observe us on the child_list.
9152	 */
9153	mutex_lock(&parent_event->child_mutex);
9154	if (is_orphaned_event(parent_event) ||
9155	    !atomic_long_inc_not_zero(&parent_event->refcount)) {
9156		mutex_unlock(&parent_event->child_mutex);
9157		free_event(child_event);
9158		return NULL;
9159	}
9160
9161	get_ctx(child_ctx);
9162
9163	/*
9164	 * Make the child state follow the state of the parent event,
9165	 * not its attr.disabled bit.  We hold the parent's mutex,
9166	 * so we won't race with perf_event_{en, dis}able_family.
9167	 */
9168	if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9169		child_event->state = PERF_EVENT_STATE_INACTIVE;
9170	else
9171		child_event->state = PERF_EVENT_STATE_OFF;
9172
9173	if (parent_event->attr.freq) {
9174		u64 sample_period = parent_event->hw.sample_period;
9175		struct hw_perf_event *hwc = &child_event->hw;
9176
9177		hwc->sample_period = sample_period;
9178		hwc->last_period   = sample_period;
9179
9180		local64_set(&hwc->period_left, sample_period);
9181	}
9182
9183	child_event->ctx = child_ctx;
9184	child_event->overflow_handler = parent_event->overflow_handler;
9185	child_event->overflow_handler_context
9186		= parent_event->overflow_handler_context;
9187
9188	/*
9189	 * Precalculate sample_data sizes
9190	 */
9191	perf_event__header_size(child_event);
9192	perf_event__id_header_size(child_event);
9193
9194	/*
9195	 * Link it up in the child's context:
9196	 */
9197	raw_spin_lock_irqsave(&child_ctx->lock, flags);
9198	add_event_to_ctx(child_event, child_ctx);
9199	raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9200
9201	/*
 
 
 
 
 
 
 
 
9202	 * Link this into the parent event's child list
9203	 */
 
 
9204	list_add_tail(&child_event->child_list, &parent_event->child_list);
9205	mutex_unlock(&parent_event->child_mutex);
9206
9207	return child_event;
9208}
9209
9210static int inherit_group(struct perf_event *parent_event,
9211	      struct task_struct *parent,
9212	      struct perf_event_context *parent_ctx,
9213	      struct task_struct *child,
9214	      struct perf_event_context *child_ctx)
9215{
9216	struct perf_event *leader;
9217	struct perf_event *sub;
9218	struct perf_event *child_ctr;
9219
9220	leader = inherit_event(parent_event, parent, parent_ctx,
9221				 child, NULL, child_ctx);
9222	if (IS_ERR(leader))
9223		return PTR_ERR(leader);
9224	list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9225		child_ctr = inherit_event(sub, parent, parent_ctx,
9226					    child, leader, child_ctx);
9227		if (IS_ERR(child_ctr))
9228			return PTR_ERR(child_ctr);
9229	}
9230	return 0;
9231}
9232
9233static int
9234inherit_task_group(struct perf_event *event, struct task_struct *parent,
9235		   struct perf_event_context *parent_ctx,
9236		   struct task_struct *child, int ctxn,
9237		   int *inherited_all)
9238{
9239	int ret;
9240	struct perf_event_context *child_ctx;
9241
9242	if (!event->attr.inherit) {
9243		*inherited_all = 0;
9244		return 0;
9245	}
9246
9247	child_ctx = child->perf_event_ctxp[ctxn];
9248	if (!child_ctx) {
9249		/*
9250		 * This is executed from the parent task context, so
9251		 * inherit events that have been marked for cloning.
9252		 * First allocate and initialize a context for the
9253		 * child.
9254		 */
9255
9256		child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9257		if (!child_ctx)
9258			return -ENOMEM;
9259
9260		child->perf_event_ctxp[ctxn] = child_ctx;
9261	}
9262
9263	ret = inherit_group(event, parent, parent_ctx,
9264			    child, child_ctx);
9265
9266	if (ret)
9267		*inherited_all = 0;
9268
9269	return ret;
9270}
9271
9272/*
9273 * Initialize the perf_event context in task_struct
9274 */
9275static int perf_event_init_context(struct task_struct *child, int ctxn)
9276{
9277	struct perf_event_context *child_ctx, *parent_ctx;
9278	struct perf_event_context *cloned_ctx;
9279	struct perf_event *event;
9280	struct task_struct *parent = current;
9281	int inherited_all = 1;
9282	unsigned long flags;
9283	int ret = 0;
9284
9285	if (likely(!parent->perf_event_ctxp[ctxn]))
9286		return 0;
9287
9288	/*
9289	 * If the parent's context is a clone, pin it so it won't get
9290	 * swapped under us.
9291	 */
9292	parent_ctx = perf_pin_task_context(parent, ctxn);
9293	if (!parent_ctx)
9294		return 0;
9295
9296	/*
9297	 * No need to check if parent_ctx != NULL here; since we saw
9298	 * it non-NULL earlier, the only reason for it to become NULL
9299	 * is if we exit, and since we're currently in the middle of
9300	 * a fork we can't be exiting at the same time.
9301	 */
9302
9303	/*
9304	 * Lock the parent list. No need to lock the child - not PID
9305	 * hashed yet and not running, so nobody can access it.
9306	 */
9307	mutex_lock(&parent_ctx->mutex);
9308
9309	/*
9310	 * We dont have to disable NMIs - we are only looking at
9311	 * the list, not manipulating it:
9312	 */
9313	list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9314		ret = inherit_task_group(event, parent, parent_ctx,
9315					 child, ctxn, &inherited_all);
9316		if (ret)
9317			break;
9318	}
9319
9320	/*
9321	 * We can't hold ctx->lock when iterating the ->flexible_group list due
9322	 * to allocations, but we need to prevent rotation because
9323	 * rotate_ctx() will change the list from interrupt context.
9324	 */
9325	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9326	parent_ctx->rotate_disable = 1;
9327	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9328
9329	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9330		ret = inherit_task_group(event, parent, parent_ctx,
9331					 child, ctxn, &inherited_all);
9332		if (ret)
9333			break;
9334	}
9335
9336	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9337	parent_ctx->rotate_disable = 0;
9338
9339	child_ctx = child->perf_event_ctxp[ctxn];
9340
9341	if (child_ctx && inherited_all) {
9342		/*
9343		 * Mark the child context as a clone of the parent
9344		 * context, or of whatever the parent is a clone of.
9345		 *
9346		 * Note that if the parent is a clone, the holding of
9347		 * parent_ctx->lock avoids it from being uncloned.
9348		 */
9349		cloned_ctx = parent_ctx->parent_ctx;
9350		if (cloned_ctx) {
9351			child_ctx->parent_ctx = cloned_ctx;
9352			child_ctx->parent_gen = parent_ctx->parent_gen;
9353		} else {
9354			child_ctx->parent_ctx = parent_ctx;
9355			child_ctx->parent_gen = parent_ctx->generation;
9356		}
9357		get_ctx(child_ctx->parent_ctx);
9358	}
9359
9360	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9361	mutex_unlock(&parent_ctx->mutex);
9362
9363	perf_unpin_context(parent_ctx);
9364	put_ctx(parent_ctx);
9365
9366	return ret;
9367}
9368
9369/*
9370 * Initialize the perf_event context in task_struct
9371 */
9372int perf_event_init_task(struct task_struct *child)
9373{
9374	int ctxn, ret;
9375
9376	memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9377	mutex_init(&child->perf_event_mutex);
9378	INIT_LIST_HEAD(&child->perf_event_list);
9379
9380	for_each_task_context_nr(ctxn) {
9381		ret = perf_event_init_context(child, ctxn);
9382		if (ret) {
9383			perf_event_free_task(child);
9384			return ret;
9385		}
9386	}
9387
9388	return 0;
9389}
9390
9391static void __init perf_event_init_all_cpus(void)
9392{
9393	struct swevent_htable *swhash;
9394	int cpu;
9395
9396	for_each_possible_cpu(cpu) {
9397		swhash = &per_cpu(swevent_htable, cpu);
9398		mutex_init(&swhash->hlist_mutex);
9399		INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9400	}
9401}
9402
9403static void perf_event_init_cpu(int cpu)
9404{
9405	struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9406
9407	mutex_lock(&swhash->hlist_mutex);
9408	if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
9409		struct swevent_hlist *hlist;
9410
9411		hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9412		WARN_ON(!hlist);
9413		rcu_assign_pointer(swhash->swevent_hlist, hlist);
9414	}
9415	mutex_unlock(&swhash->hlist_mutex);
9416}
9417
9418#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
 
 
 
 
 
 
 
 
 
9419static void __perf_event_exit_context(void *__info)
9420{
9421	struct perf_event_context *ctx = __info;
9422	struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9423	struct perf_event *event;
9424
9425	raw_spin_lock(&ctx->lock);
9426	list_for_each_entry(event, &ctx->event_list, event_entry)
9427		__perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
9428	raw_spin_unlock(&ctx->lock);
 
 
9429}
9430
9431static void perf_event_exit_cpu_context(int cpu)
9432{
9433	struct perf_event_context *ctx;
9434	struct pmu *pmu;
9435	int idx;
9436
9437	idx = srcu_read_lock(&pmus_srcu);
9438	list_for_each_entry_rcu(pmu, &pmus, entry) {
9439		ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9440
9441		mutex_lock(&ctx->mutex);
9442		smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9443		mutex_unlock(&ctx->mutex);
9444	}
9445	srcu_read_unlock(&pmus_srcu, idx);
9446}
9447
9448static void perf_event_exit_cpu(int cpu)
9449{
 
 
 
 
 
 
9450	perf_event_exit_cpu_context(cpu);
9451}
9452#else
9453static inline void perf_event_exit_cpu(int cpu) { }
9454#endif
9455
9456static int
9457perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9458{
9459	int cpu;
9460
9461	for_each_online_cpu(cpu)
9462		perf_event_exit_cpu(cpu);
9463
9464	return NOTIFY_OK;
9465}
9466
9467/*
9468 * Run the perf reboot notifier at the very last possible moment so that
9469 * the generic watchdog code runs as long as possible.
9470 */
9471static struct notifier_block perf_reboot_notifier = {
9472	.notifier_call = perf_reboot,
9473	.priority = INT_MIN,
9474};
9475
9476static int
9477perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9478{
9479	unsigned int cpu = (long)hcpu;
9480
9481	switch (action & ~CPU_TASKS_FROZEN) {
9482
9483	case CPU_UP_PREPARE:
9484		/*
9485		 * This must be done before the CPU comes alive, because the
9486		 * moment we can run tasks we can encounter (software) events.
9487		 *
9488		 * Specifically, someone can have inherited events on kthreadd
9489		 * or a pre-existing worker thread that gets re-bound.
9490		 */
9491		perf_event_init_cpu(cpu);
9492		break;
9493
 
9494	case CPU_DOWN_PREPARE:
9495		/*
9496		 * This must be done before the CPU dies because after that an
9497		 * active event might want to IPI the CPU and that'll not work
9498		 * so great for dead CPUs.
9499		 *
9500		 * XXX smp_call_function_single() return -ENXIO without a warn
9501		 * so we could possibly deal with this.
9502		 *
9503		 * This is safe against new events arriving because
9504		 * sys_perf_event_open() serializes against hotplug using
9505		 * get_online_cpus().
9506		 */
9507		perf_event_exit_cpu(cpu);
9508		break;
 
9509	default:
9510		break;
9511	}
9512
9513	return NOTIFY_OK;
9514}
9515
9516void __init perf_event_init(void)
9517{
9518	int ret;
9519
9520	idr_init(&pmu_idr);
9521
9522	perf_event_init_all_cpus();
9523	init_srcu_struct(&pmus_srcu);
9524	perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9525	perf_pmu_register(&perf_cpu_clock, NULL, -1);
9526	perf_pmu_register(&perf_task_clock, NULL, -1);
9527	perf_tp_register();
9528	perf_cpu_notifier(perf_cpu_notify);
9529	register_reboot_notifier(&perf_reboot_notifier);
9530
9531	ret = init_hw_breakpoint();
9532	WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9533
9534	/*
9535	 * Build time assertion that we keep the data_head at the intended
9536	 * location.  IOW, validation we got the __reserved[] size right.
9537	 */
9538	BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9539		     != 1024);
9540}
9541
9542ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9543			      char *page)
9544{
9545	struct perf_pmu_events_attr *pmu_attr =
9546		container_of(attr, struct perf_pmu_events_attr, attr);
9547
9548	if (pmu_attr->event_str)
9549		return sprintf(page, "%s\n", pmu_attr->event_str);
9550
9551	return 0;
9552}
9553EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
9554
9555static int __init perf_event_sysfs_init(void)
9556{
9557	struct pmu *pmu;
9558	int ret;
9559
9560	mutex_lock(&pmus_lock);
9561
9562	ret = bus_register(&pmu_bus);
9563	if (ret)
9564		goto unlock;
9565
9566	list_for_each_entry(pmu, &pmus, entry) {
9567		if (!pmu->name || pmu->type < 0)
9568			continue;
9569
9570		ret = pmu_dev_alloc(pmu);
9571		WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9572	}
9573	pmu_bus_running = 1;
9574	ret = 0;
9575
9576unlock:
9577	mutex_unlock(&pmus_lock);
9578
9579	return ret;
9580}
9581device_initcall(perf_event_sysfs_init);
9582
9583#ifdef CONFIG_CGROUP_PERF
9584static struct cgroup_subsys_state *
9585perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9586{
9587	struct perf_cgroup *jc;
9588
9589	jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9590	if (!jc)
9591		return ERR_PTR(-ENOMEM);
9592
9593	jc->info = alloc_percpu(struct perf_cgroup_info);
9594	if (!jc->info) {
9595		kfree(jc);
9596		return ERR_PTR(-ENOMEM);
9597	}
9598
9599	return &jc->css;
9600}
9601
9602static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
 
9603{
9604	struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9605
 
9606	free_percpu(jc->info);
9607	kfree(jc);
9608}
9609
9610static int __perf_cgroup_move(void *info)
9611{
9612	struct task_struct *task = info;
9613	rcu_read_lock();
9614	perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9615	rcu_read_unlock();
9616	return 0;
9617}
9618
9619static void perf_cgroup_attach(struct cgroup_taskset *tset)
 
9620{
9621	struct task_struct *task;
9622	struct cgroup_subsys_state *css;
 
 
 
 
 
 
 
 
 
 
 
9623
9624	cgroup_taskset_for_each(task, css, tset)
9625		task_function_call(task, __perf_cgroup_move, task);
9626}
9627
9628struct cgroup_subsys perf_event_cgrp_subsys = {
9629	.css_alloc	= perf_cgroup_css_alloc,
9630	.css_free	= perf_cgroup_css_free,
9631	.attach		= perf_cgroup_attach,
 
 
 
9632};
9633#endif /* CONFIG_CGROUP_PERF */