1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * event tracer
   4 *
   5 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   6 *
   7 *  - Added format output of fields of the trace point.
   8 *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
   9 *
  10 */
  11
  12#define pr_fmt(fmt) fmt
  13
  14#include <linux/workqueue.h>
  15#include <linux/security.h>
  16#include <linux/spinlock.h>
  17#include <linux/kthread.h>
  18#include <linux/tracefs.h>
  19#include <linux/uaccess.h>
  20#include <linux/module.h>
  21#include <linux/ctype.h>
  22#include <linux/sort.h>
  23#include <linux/slab.h>
  24#include <linux/delay.h>
  25
  26#include <trace/events/sched.h>
  27#include <trace/syscall.h>
  28
  29#include <asm/setup.h>
  30
  31#include "trace_output.h"
  32
  33#undef TRACE_SYSTEM
  34#define TRACE_SYSTEM "TRACE_SYSTEM"
  35
  36DEFINE_MUTEX(event_mutex);
  37
  38LIST_HEAD(ftrace_events);
  39static LIST_HEAD(ftrace_generic_fields);
  40static LIST_HEAD(ftrace_common_fields);
  41static bool eventdir_initialized;
  42
  43static LIST_HEAD(module_strings);
  44
  45struct module_string {
  46	struct list_head	next;
  47	struct module		*module;
  48	char			*str;
  49};
  50
  51#define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
  52
  53static struct kmem_cache *field_cachep;
  54static struct kmem_cache *file_cachep;
  55
  56static inline int system_refcount(struct event_subsystem *system)
  57{
  58	return system->ref_count;
  59}
  60
  61static int system_refcount_inc(struct event_subsystem *system)
  62{
  63	return system->ref_count++;
  64}
  65
  66static int system_refcount_dec(struct event_subsystem *system)
  67{
  68	return --system->ref_count;
  69}
  70
  71/* Double loops, do not use break, only goto's work */
  72#define do_for_each_event_file(tr, file)			\
  73	list_for_each_entry(tr, &ftrace_trace_arrays, list) {	\
  74		list_for_each_entry(file, &tr->events, list)
  75
  76#define do_for_each_event_file_safe(tr, file)			\
  77	list_for_each_entry(tr, &ftrace_trace_arrays, list) {	\
  78		struct trace_event_file *___n;				\
  79		list_for_each_entry_safe(file, ___n, &tr->events, list)
  80
  81#define while_for_each_event_file()		\
  82	}
  83
  84static struct ftrace_event_field *
  85__find_event_field(struct list_head *head, char *name)
  86{
  87	struct ftrace_event_field *field;
  88
  89	list_for_each_entry(field, head, link) {
  90		if (!strcmp(field->name, name))
  91			return field;
  92	}
  93
  94	return NULL;
  95}
  96
  97struct ftrace_event_field *
  98trace_find_event_field(struct trace_event_call *call, char *name)
  99{
 100	struct ftrace_event_field *field;
 101	struct list_head *head;
 102
 103	head = trace_get_fields(call);
 104	field = __find_event_field(head, name);
 105	if (field)
 106		return field;
 107
 108	field = __find_event_field(&ftrace_generic_fields, name);
 109	if (field)
 110		return field;
 111
 112	return __find_event_field(&ftrace_common_fields, name);
 113}
 114
 115static int __trace_define_field(struct list_head *head, const char *type,
 116				const char *name, int offset, int size,
 117				int is_signed, int filter_type, int len)
 
 118{
 119	struct ftrace_event_field *field;
 120
 121	field = kmem_cache_alloc(field_cachep, GFP_TRACE);
 122	if (!field)
 123		return -ENOMEM;
 124
 125	field->name = name;
 126	field->type = type;
 127
 128	if (filter_type == FILTER_OTHER)
 129		field->filter_type = filter_assign_type(type);
 130	else
 131		field->filter_type = filter_type;
 132
 133	field->offset = offset;
 134	field->size = size;
 135	field->is_signed = is_signed;
 
 136	field->len = len;
 137
 138	list_add(&field->link, head);
 139
 140	return 0;
 141}
 142
 143int trace_define_field(struct trace_event_call *call, const char *type,
 144		       const char *name, int offset, int size, int is_signed,
 145		       int filter_type)
 146{
 147	struct list_head *head;
 148
 149	if (WARN_ON(!call->class))
 150		return 0;
 151
 152	head = trace_get_fields(call);
 153	return __trace_define_field(head, type, name, offset, size,
 154				    is_signed, filter_type, 0);
 155}
 156EXPORT_SYMBOL_GPL(trace_define_field);
 157
 158static int trace_define_field_ext(struct trace_event_call *call, const char *type,
 159		       const char *name, int offset, int size, int is_signed,
 160		       int filter_type, int len)
 161{
 162	struct list_head *head;
 163
 164	if (WARN_ON(!call->class))
 165		return 0;
 166
 167	head = trace_get_fields(call);
 168	return __trace_define_field(head, type, name, offset, size,
 169				    is_signed, filter_type, len);
 170}
 171
 172#define __generic_field(type, item, filter_type)			\
 173	ret = __trace_define_field(&ftrace_generic_fields, #type,	\
 174				   #item, 0, 0, is_signed_type(type),	\
 175				   filter_type, 0);			\
 176	if (ret)							\
 177		return ret;
 178
 179#define __common_field(type, item)					\
 180	ret = __trace_define_field(&ftrace_common_fields, #type,	\
 181				   "common_" #item,			\
 182				   offsetof(typeof(ent), item),		\
 183				   sizeof(ent.item),			\
 184				   is_signed_type(type), FILTER_OTHER, 0);	\
 
 185	if (ret)							\
 186		return ret;
 187
 188static int trace_define_generic_fields(void)
 189{
 190	int ret;
 191
 192	__generic_field(int, CPU, FILTER_CPU);
 193	__generic_field(int, cpu, FILTER_CPU);
 194	__generic_field(int, common_cpu, FILTER_CPU);
 195	__generic_field(char *, COMM, FILTER_COMM);
 196	__generic_field(char *, comm, FILTER_COMM);
 
 
 197
 198	return ret;
 199}
 200
 201static int trace_define_common_fields(void)
 202{
 203	int ret;
 204	struct trace_entry ent;
 205
 206	__common_field(unsigned short, type);
 207	__common_field(unsigned char, flags);
 208	/* Holds both preempt_count and migrate_disable */
 209	__common_field(unsigned char, preempt_count);
 210	__common_field(int, pid);
 211
 212	return ret;
 213}
 214
 215static void trace_destroy_fields(struct trace_event_call *call)
 216{
 217	struct ftrace_event_field *field, *next;
 218	struct list_head *head;
 219
 220	head = trace_get_fields(call);
 221	list_for_each_entry_safe(field, next, head, link) {
 222		list_del(&field->link);
 223		kmem_cache_free(field_cachep, field);
 224	}
 225}
 226
 227/*
 228 * run-time version of trace_event_get_offsets_<call>() that returns the last
 229 * accessible offset of trace fields excluding __dynamic_array bytes
 230 */
 231int trace_event_get_offsets(struct trace_event_call *call)
 232{
 233	struct ftrace_event_field *tail;
 234	struct list_head *head;
 235
 236	head = trace_get_fields(call);
 237	/*
 238	 * head->next points to the last field with the largest offset,
 239	 * since it was added last by trace_define_field()
 240	 */
 241	tail = list_first_entry(head, struct ftrace_event_field, link);
 242	return tail->offset + tail->size;
 243}
 244
 245/*
 246 * Check if the referenced field is an array and return true,
 247 * as arrays are OK to dereference.
 248 */
 249static bool test_field(const char *fmt, struct trace_event_call *call)
 250{
 251	struct trace_event_fields *field = call->class->fields_array;
 252	const char *array_descriptor;
 253	const char *p = fmt;
 254	int len;
 255
 256	if (!(len = str_has_prefix(fmt, "REC->")))
 257		return false;
 258	fmt += len;
 259	for (p = fmt; *p; p++) {
 260		if (!isalnum(*p) && *p != '_')
 261			break;
 262	}
 263	len = p - fmt;
 264
 265	for (; field->type; field++) {
 266		if (strncmp(field->name, fmt, len) ||
 267		    field->name[len])
 268			continue;
 269		array_descriptor = strchr(field->type, '[');
 270		/* This is an array and is OK to dereference. */
 271		return array_descriptor != NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 272	}
 273	return false;
 274}
 275
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 276/*
 277 * Examine the print fmt of the event looking for unsafe dereference
 278 * pointers using %p* that could be recorded in the trace event and
 279 * much later referenced after the pointer was freed. Dereferencing
 280 * pointers are OK, if it is dereferenced into the event itself.
 281 */
 282static void test_event_printk(struct trace_event_call *call)
 283{
 284	u64 dereference_flags = 0;
 
 285	bool first = true;
 286	const char *fmt, *c, *r, *a;
 287	int parens = 0;
 288	char in_quote = 0;
 289	int start_arg = 0;
 290	int arg = 0;
 291	int i;
 292
 293	fmt = call->print_fmt;
 294
 295	if (!fmt)
 296		return;
 297
 298	for (i = 0; fmt[i]; i++) {
 299		switch (fmt[i]) {
 300		case '\\':
 301			i++;
 302			if (!fmt[i])
 303				return;
 304			continue;
 305		case '"':
 306		case '\'':
 307			/*
 308			 * The print fmt starts with a string that
 309			 * is processed first to find %p* usage,
 310			 * then after the first string, the print fmt
 311			 * contains arguments that are used to check
 312			 * if the dereferenced %p* usage is safe.
 313			 */
 314			if (first) {
 315				if (fmt[i] == '\'')
 316					continue;
 317				if (in_quote) {
 318					arg = 0;
 319					first = false;
 320					/*
 321					 * If there was no %p* uses
 322					 * the fmt is OK.
 323					 */
 324					if (!dereference_flags)
 325						return;
 326				}
 327			}
 328			if (in_quote) {
 329				if (in_quote == fmt[i])
 330					in_quote = 0;
 331			} else {
 332				in_quote = fmt[i];
 333			}
 334			continue;
 335		case '%':
 336			if (!first || !in_quote)
 337				continue;
 338			i++;
 339			if (!fmt[i])
 340				return;
 341			switch (fmt[i]) {
 342			case '%':
 343				continue;
 344			case 'p':
 345				/* Find dereferencing fields */
 346				switch (fmt[i + 1]) {
 347				case 'B': case 'R': case 'r':
 348				case 'b': case 'M': case 'm':
 349				case 'I': case 'i': case 'E':
 350				case 'U': case 'V': case 'N':
 351				case 'a': case 'd': case 'D':
 352				case 'g': case 't': case 'C':
 353				case 'O': case 'f':
 354					if (WARN_ONCE(arg == 63,
 355						      "Too many args for event: %s",
 356						      trace_event_name(call)))
 357						return;
 358					dereference_flags |= 1ULL << arg;
 359				}
 360				break;
 361			default:
 362			{
 363				bool star = false;
 364				int j;
 365
 366				/* Increment arg if %*s exists. */
 367				for (j = 0; fmt[i + j]; j++) {
 368					if (isdigit(fmt[i + j]) ||
 369					    fmt[i + j] == '.')
 370						continue;
 371					if (fmt[i + j] == '*') {
 372						star = true;
 373						continue;
 374					}
 375					if ((fmt[i + j] == 's') && star)
 376						arg++;
 
 
 
 
 
 
 
 
 377					break;
 378				}
 379				break;
 380			} /* default */
 381
 382			} /* switch */
 383			arg++;
 384			continue;
 385		case '(':
 386			if (in_quote)
 387				continue;
 388			parens++;
 389			continue;
 390		case ')':
 391			if (in_quote)
 392				continue;
 393			parens--;
 394			if (WARN_ONCE(parens < 0,
 395				      "Paren mismatch for event: %s\narg='%s'\n%*s",
 396				      trace_event_name(call),
 397				      fmt + start_arg,
 398				      (i - start_arg) + 5, "^"))
 399				return;
 400			continue;
 401		case ',':
 402			if (in_quote || parens)
 403				continue;
 
 404			i++;
 405			while (isspace(fmt[i]))
 406				i++;
 407			start_arg = i;
 408			if (!(dereference_flags & (1ULL << arg)))
 409				goto next_arg;
 410
 411			/* Find the REC-> in the argument */
 412			c = strchr(fmt + i, ',');
 413			r = strstr(fmt + i, "REC->");
 414			if (r && (!c || r < c)) {
 415				/*
 416				 * Addresses of events on the buffer,
 417				 * or an array on the buffer is
 418				 * OK to dereference.
 419				 * There's ways to fool this, but
 420				 * this is to catch common mistakes,
 421				 * not malicious code.
 422				 */
 423				a = strchr(fmt + i, '&');
 424				if ((a && (a < r)) || test_field(r, call))
 
 
 
 
 425					dereference_flags &= ~(1ULL << arg);
 426			} else if ((r = strstr(fmt + i, "__get_dynamic_array(")) &&
 427				   (!c || r < c)) {
 428				dereference_flags &= ~(1ULL << arg);
 429			} else if ((r = strstr(fmt + i, "__get_sockaddr(")) &&
 430				   (!c || r < c)) {
 431				dereference_flags &= ~(1ULL << arg);
 432			}
 433
 434		next_arg:
 435			i--;
 436			arg++;
 
 
 437		}
 438	}
 439
 
 
 
 
 
 
 
 
 440	/*
 441	 * If you triggered the below warning, the trace event reported
 442	 * uses an unsafe dereference pointer %p*. As the data stored
 443	 * at the trace event time may no longer exist when the trace
 444	 * event is printed, dereferencing to the original source is
 445	 * unsafe. The source of the dereference must be copied into the
 446	 * event itself, and the dereference must access the copy instead.
 447	 */
 448	if (WARN_ON_ONCE(dereference_flags)) {
 449		arg = 1;
 450		while (!(dereference_flags & 1)) {
 451			dereference_flags >>= 1;
 452			arg++;
 453		}
 454		pr_warn("event %s has unsafe dereference of argument %d\n",
 455			trace_event_name(call), arg);
 456		pr_warn("print_fmt: %s\n", fmt);
 457	}
 458}
 459
 460int trace_event_raw_init(struct trace_event_call *call)
 461{
 462	int id;
 463
 464	id = register_trace_event(&call->event);
 465	if (!id)
 466		return -ENODEV;
 467
 468	test_event_printk(call);
 469
 470	return 0;
 471}
 472EXPORT_SYMBOL_GPL(trace_event_raw_init);
 473
 474bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 475{
 476	struct trace_array *tr = trace_file->tr;
 477	struct trace_array_cpu *data;
 478	struct trace_pid_list *no_pid_list;
 479	struct trace_pid_list *pid_list;
 480
 481	pid_list = rcu_dereference_raw(tr->filtered_pids);
 482	no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 483
 484	if (!pid_list && !no_pid_list)
 485		return false;
 486
 487	data = this_cpu_ptr(tr->array_buffer.data);
 488
 489	return data->ignore_pid;
 490}
 491EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
 492
 493void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 494				 struct trace_event_file *trace_file,
 495				 unsigned long len)
 496{
 497	struct trace_event_call *event_call = trace_file->event_call;
 498
 499	if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
 500	    trace_event_ignore_this_pid(trace_file))
 501		return NULL;
 502
 503	/*
 504	 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
 505	 * preemption (adding one to the preempt_count). Since we are
 506	 * interested in the preempt_count at the time the tracepoint was
 507	 * hit, we need to subtract one to offset the increment.
 508	 */
 509	fbuffer->trace_ctx = tracing_gen_ctx_dec();
 510	fbuffer->trace_file = trace_file;
 511
 512	fbuffer->event =
 513		trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
 514						event_call->event.type, len,
 515						fbuffer->trace_ctx);
 516	if (!fbuffer->event)
 517		return NULL;
 518
 519	fbuffer->regs = NULL;
 520	fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 521	return fbuffer->entry;
 522}
 523EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 524
 525int trace_event_reg(struct trace_event_call *call,
 526		    enum trace_reg type, void *data)
 527{
 528	struct trace_event_file *file = data;
 529
 530	WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
 531	switch (type) {
 532	case TRACE_REG_REGISTER:
 533		return tracepoint_probe_register(call->tp,
 534						 call->class->probe,
 535						 file);
 536	case TRACE_REG_UNREGISTER:
 537		tracepoint_probe_unregister(call->tp,
 538					    call->class->probe,
 539					    file);
 540		return 0;
 541
 542#ifdef CONFIG_PERF_EVENTS
 543	case TRACE_REG_PERF_REGISTER:
 544		return tracepoint_probe_register(call->tp,
 545						 call->class->perf_probe,
 546						 call);
 547	case TRACE_REG_PERF_UNREGISTER:
 548		tracepoint_probe_unregister(call->tp,
 549					    call->class->perf_probe,
 550					    call);
 551		return 0;
 552	case TRACE_REG_PERF_OPEN:
 553	case TRACE_REG_PERF_CLOSE:
 554	case TRACE_REG_PERF_ADD:
 555	case TRACE_REG_PERF_DEL:
 556		return 0;
 557#endif
 558	}
 559	return 0;
 560}
 561EXPORT_SYMBOL_GPL(trace_event_reg);
 562
 563void trace_event_enable_cmd_record(bool enable)
 564{
 565	struct trace_event_file *file;
 566	struct trace_array *tr;
 567
 568	lockdep_assert_held(&event_mutex);
 569
 570	do_for_each_event_file(tr, file) {
 571
 572		if (!(file->flags & EVENT_FILE_FL_ENABLED))
 573			continue;
 574
 575		if (enable) {
 576			tracing_start_cmdline_record();
 577			set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 578		} else {
 579			tracing_stop_cmdline_record();
 580			clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 581		}
 582	} while_for_each_event_file();
 583}
 584
 585void trace_event_enable_tgid_record(bool enable)
 586{
 587	struct trace_event_file *file;
 588	struct trace_array *tr;
 589
 590	lockdep_assert_held(&event_mutex);
 591
 592	do_for_each_event_file(tr, file) {
 593		if (!(file->flags & EVENT_FILE_FL_ENABLED))
 594			continue;
 595
 596		if (enable) {
 597			tracing_start_tgid_record();
 598			set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 599		} else {
 600			tracing_stop_tgid_record();
 601			clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
 602				  &file->flags);
 603		}
 604	} while_for_each_event_file();
 605}
 606
 607static int __ftrace_event_enable_disable(struct trace_event_file *file,
 608					 int enable, int soft_disable)
 609{
 610	struct trace_event_call *call = file->event_call;
 611	struct trace_array *tr = file->tr;
 612	unsigned long file_flags = file->flags;
 613	int ret = 0;
 614	int disable;
 615
 616	switch (enable) {
 617	case 0:
 618		/*
 619		 * When soft_disable is set and enable is cleared, the sm_ref
 620		 * reference counter is decremented. If it reaches 0, we want
 621		 * to clear the SOFT_DISABLED flag but leave the event in the
 622		 * state that it was. That is, if the event was enabled and
 623		 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
 624		 * is set we do not want the event to be enabled before we
 625		 * clear the bit.
 626		 *
 627		 * When soft_disable is not set but the SOFT_MODE flag is,
 628		 * we do nothing. Do not disable the tracepoint, otherwise
 629		 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 630		 */
 631		if (soft_disable) {
 632			if (atomic_dec_return(&file->sm_ref) > 0)
 633				break;
 634			disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 635			clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 
 
 636		} else
 637			disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 638
 639		if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
 640			clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 641			if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
 642				tracing_stop_cmdline_record();
 643				clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 644			}
 645
 646			if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
 647				tracing_stop_tgid_record();
 648				clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 649			}
 650
 651			call->class->reg(call, TRACE_REG_UNREGISTER, file);
 652		}
 653		/* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 654		if (file->flags & EVENT_FILE_FL_SOFT_MODE)
 655			set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 656		else
 657			clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 658		break;
 659	case 1:
 660		/*
 661		 * When soft_disable is set and enable is set, we want to
 662		 * register the tracepoint for the event, but leave the event
 663		 * as is. That means, if the event was already enabled, we do
 664		 * nothing (but set SOFT_MODE). If the event is disabled, we
 665		 * set SOFT_DISABLED before enabling the event tracepoint, so
 666		 * it still seems to be disabled.
 667		 */
 668		if (!soft_disable)
 669			clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 670		else {
 671			if (atomic_inc_return(&file->sm_ref) > 1)
 672				break;
 673			set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 
 
 674		}
 675
 676		if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
 677			bool cmd = false, tgid = false;
 678
 679			/* Keep the event disabled, when going to SOFT_MODE. */
 680			if (soft_disable)
 681				set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 682
 683			if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
 684				cmd = true;
 685				tracing_start_cmdline_record();
 686				set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 687			}
 688
 689			if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
 690				tgid = true;
 691				tracing_start_tgid_record();
 692				set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 693			}
 694
 695			ret = call->class->reg(call, TRACE_REG_REGISTER, file);
 696			if (ret) {
 697				if (cmd)
 698					tracing_stop_cmdline_record();
 699				if (tgid)
 700					tracing_stop_tgid_record();
 701				pr_info("event trace: Could not enable event "
 702					"%s\n", trace_event_name(call));
 703				break;
 704			}
 705			set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 706
 707			/* WAS_ENABLED gets set but never cleared. */
 708			set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
 709		}
 710		break;
 711	}
 712
 713	/* Enable or disable use of trace_buffered_event */
 714	if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
 715	    (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
 716		if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
 717			trace_buffered_event_enable();
 718		else
 719			trace_buffered_event_disable();
 720	}
 721
 722	return ret;
 723}
 724
 725int trace_event_enable_disable(struct trace_event_file *file,
 726			       int enable, int soft_disable)
 727{
 728	return __ftrace_event_enable_disable(file, enable, soft_disable);
 729}
 730
 731static int ftrace_event_enable_disable(struct trace_event_file *file,
 732				       int enable)
 733{
 734	return __ftrace_event_enable_disable(file, enable, 0);
 735}
 736
 737static void ftrace_clear_events(struct trace_array *tr)
 738{
 739	struct trace_event_file *file;
 740
 741	mutex_lock(&event_mutex);
 742	list_for_each_entry(file, &tr->events, list) {
 743		ftrace_event_enable_disable(file, 0);
 744	}
 745	mutex_unlock(&event_mutex);
 746}
 747
 748static void
 749event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 750{
 751	struct trace_pid_list *pid_list;
 752	struct trace_array *tr = data;
 753
 754	pid_list = rcu_dereference_raw(tr->filtered_pids);
 755	trace_filter_add_remove_task(pid_list, NULL, task);
 756
 757	pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 758	trace_filter_add_remove_task(pid_list, NULL, task);
 759}
 760
 761static void
 762event_filter_pid_sched_process_fork(void *data,
 763				    struct task_struct *self,
 764				    struct task_struct *task)
 765{
 766	struct trace_pid_list *pid_list;
 767	struct trace_array *tr = data;
 768
 769	pid_list = rcu_dereference_sched(tr->filtered_pids);
 770	trace_filter_add_remove_task(pid_list, self, task);
 771
 772	pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 773	trace_filter_add_remove_task(pid_list, self, task);
 774}
 775
 776void trace_event_follow_fork(struct trace_array *tr, bool enable)
 777{
 778	if (enable) {
 779		register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 780						       tr, INT_MIN);
 781		register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 782						       tr, INT_MAX);
 783	} else {
 784		unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 785						    tr);
 786		unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 787						    tr);
 788	}
 789}
 790
 791static void
 792event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 793					struct task_struct *prev,
 794					struct task_struct *next,
 795					unsigned int prev_state)
 796{
 797	struct trace_array *tr = data;
 798	struct trace_pid_list *no_pid_list;
 799	struct trace_pid_list *pid_list;
 800	bool ret;
 801
 802	pid_list = rcu_dereference_sched(tr->filtered_pids);
 803	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 804
 805	/*
 806	 * Sched switch is funny, as we only want to ignore it
 807	 * in the notrace case if both prev and next should be ignored.
 808	 */
 809	ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
 810		trace_ignore_this_task(NULL, no_pid_list, next);
 811
 812	this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
 813		       (trace_ignore_this_task(pid_list, NULL, prev) &&
 814			trace_ignore_this_task(pid_list, NULL, next)));
 815}
 816
 817static void
 818event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 819					 struct task_struct *prev,
 820					 struct task_struct *next,
 821					 unsigned int prev_state)
 822{
 823	struct trace_array *tr = data;
 824	struct trace_pid_list *no_pid_list;
 825	struct trace_pid_list *pid_list;
 826
 827	pid_list = rcu_dereference_sched(tr->filtered_pids);
 828	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 829
 830	this_cpu_write(tr->array_buffer.data->ignore_pid,
 831		       trace_ignore_this_task(pid_list, no_pid_list, next));
 832}
 833
 834static void
 835event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 836{
 837	struct trace_array *tr = data;
 838	struct trace_pid_list *no_pid_list;
 839	struct trace_pid_list *pid_list;
 840
 841	/* Nothing to do if we are already tracing */
 842	if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
 843		return;
 844
 845	pid_list = rcu_dereference_sched(tr->filtered_pids);
 846	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 847
 848	this_cpu_write(tr->array_buffer.data->ignore_pid,
 849		       trace_ignore_this_task(pid_list, no_pid_list, task));
 850}
 851
 852static void
 853event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 854{
 855	struct trace_array *tr = data;
 856	struct trace_pid_list *no_pid_list;
 857	struct trace_pid_list *pid_list;
 858
 859	/* Nothing to do if we are not tracing */
 860	if (this_cpu_read(tr->array_buffer.data->ignore_pid))
 861		return;
 862
 863	pid_list = rcu_dereference_sched(tr->filtered_pids);
 864	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 865
 866	/* Set tracing if current is enabled */
 867	this_cpu_write(tr->array_buffer.data->ignore_pid,
 868		       trace_ignore_this_task(pid_list, no_pid_list, current));
 869}
 870
 871static void unregister_pid_events(struct trace_array *tr)
 872{
 873	unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 874	unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 875
 876	unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
 877	unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
 878
 879	unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
 880	unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
 881
 882	unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 883	unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
 884}
 885
 886static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
 887{
 888	struct trace_pid_list *pid_list;
 889	struct trace_pid_list *no_pid_list;
 890	struct trace_event_file *file;
 891	int cpu;
 892
 893	pid_list = rcu_dereference_protected(tr->filtered_pids,
 894					     lockdep_is_held(&event_mutex));
 895	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
 896					     lockdep_is_held(&event_mutex));
 897
 898	/* Make sure there's something to do */
 899	if (!pid_type_enabled(type, pid_list, no_pid_list))
 900		return;
 901
 902	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
 903		unregister_pid_events(tr);
 904
 905		list_for_each_entry(file, &tr->events, list) {
 906			clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
 907		}
 908
 909		for_each_possible_cpu(cpu)
 910			per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 911	}
 912
 913	if (type & TRACE_PIDS)
 914		rcu_assign_pointer(tr->filtered_pids, NULL);
 915
 916	if (type & TRACE_NO_PIDS)
 917		rcu_assign_pointer(tr->filtered_no_pids, NULL);
 918
 919	/* Wait till all users are no longer using pid filtering */
 920	tracepoint_synchronize_unregister();
 921
 922	if ((type & TRACE_PIDS) && pid_list)
 923		trace_pid_list_free(pid_list);
 924
 925	if ((type & TRACE_NO_PIDS) && no_pid_list)
 926		trace_pid_list_free(no_pid_list);
 927}
 928
 929static void ftrace_clear_event_pids(struct trace_array *tr, int type)
 930{
 931	mutex_lock(&event_mutex);
 932	__ftrace_clear_event_pids(tr, type);
 933	mutex_unlock(&event_mutex);
 934}
 935
 936static void __put_system(struct event_subsystem *system)
 937{
 938	struct event_filter *filter = system->filter;
 939
 940	WARN_ON_ONCE(system_refcount(system) == 0);
 941	if (system_refcount_dec(system))
 942		return;
 943
 944	list_del(&system->list);
 945
 946	if (filter) {
 947		kfree(filter->filter_string);
 948		kfree(filter);
 949	}
 950	kfree_const(system->name);
 951	kfree(system);
 952}
 953
 954static void __get_system(struct event_subsystem *system)
 955{
 956	WARN_ON_ONCE(system_refcount(system) == 0);
 957	system_refcount_inc(system);
 958}
 959
 960static void __get_system_dir(struct trace_subsystem_dir *dir)
 961{
 962	WARN_ON_ONCE(dir->ref_count == 0);
 963	dir->ref_count++;
 964	__get_system(dir->subsystem);
 965}
 966
 967static void __put_system_dir(struct trace_subsystem_dir *dir)
 968{
 969	WARN_ON_ONCE(dir->ref_count == 0);
 970	/* If the subsystem is about to be freed, the dir must be too */
 971	WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
 972
 973	__put_system(dir->subsystem);
 974	if (!--dir->ref_count)
 975		kfree(dir);
 976}
 977
 978static void put_system(struct trace_subsystem_dir *dir)
 979{
 980	mutex_lock(&event_mutex);
 981	__put_system_dir(dir);
 982	mutex_unlock(&event_mutex);
 983}
 984
 985static void remove_subsystem(struct trace_subsystem_dir *dir)
 986{
 987	if (!dir)
 988		return;
 989
 990	if (!--dir->nr_events) {
 991		tracefs_remove(dir->entry);
 992		list_del(&dir->list);
 993		__put_system_dir(dir);
 994	}
 995}
 996
 997static void remove_event_file_dir(struct trace_event_file *file)
 998{
 999	struct dentry *dir = file->dir;
1000	struct dentry *child;
1001
1002	if (dir) {
1003		spin_lock(&dir->d_lock);	/* probably unneeded */
1004		list_for_each_entry(child, &dir->d_subdirs, d_child) {
1005			if (d_really_is_positive(child))	/* probably unneeded */
1006				d_inode(child)->i_private = NULL;
1007		}
1008		spin_unlock(&dir->d_lock);
1009
1010		tracefs_remove(dir);
 
 
 
 
1011	}
 
1012
 
 
 
1013	list_del(&file->list);
1014	remove_subsystem(file->system);
1015	free_event_filter(file->filter);
1016	kmem_cache_free(file_cachep, file);
 
1017}
1018
1019/*
1020 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
1021 */
1022static int
1023__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
1024			      const char *sub, const char *event, int set)
1025{
1026	struct trace_event_file *file;
1027	struct trace_event_call *call;
1028	const char *name;
1029	int ret = -EINVAL;
1030	int eret = 0;
1031
1032	list_for_each_entry(file, &tr->events, list) {
1033
1034		call = file->event_call;
1035		name = trace_event_name(call);
1036
1037		if (!name || !call->class || !call->class->reg)
1038			continue;
1039
1040		if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
1041			continue;
1042
1043		if (match &&
1044		    strcmp(match, name) != 0 &&
1045		    strcmp(match, call->class->system) != 0)
1046			continue;
1047
1048		if (sub && strcmp(sub, call->class->system) != 0)
1049			continue;
1050
1051		if (event && strcmp(event, name) != 0)
1052			continue;
1053
1054		ret = ftrace_event_enable_disable(file, set);
1055
1056		/*
1057		 * Save the first error and return that. Some events
1058		 * may still have been enabled, but let the user
1059		 * know that something went wrong.
1060		 */
1061		if (ret && !eret)
1062			eret = ret;
1063
1064		ret = eret;
1065	}
1066
1067	return ret;
1068}
1069
1070static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
1071				  const char *sub, const char *event, int set)
1072{
1073	int ret;
1074
1075	mutex_lock(&event_mutex);
1076	ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
1077	mutex_unlock(&event_mutex);
1078
1079	return ret;
1080}
1081
1082int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
1083{
1084	char *event = NULL, *sub = NULL, *match;
1085	int ret;
1086
1087	if (!tr)
1088		return -ENOENT;
1089	/*
1090	 * The buf format can be <subsystem>:<event-name>
1091	 *  *:<event-name> means any event by that name.
1092	 *  :<event-name> is the same.
1093	 *
1094	 *  <subsystem>:* means all events in that subsystem
1095	 *  <subsystem>: means the same.
1096	 *
1097	 *  <name> (no ':') means all events in a subsystem with
1098	 *  the name <name> or any event that matches <name>
1099	 */
1100
1101	match = strsep(&buf, ":");
1102	if (buf) {
1103		sub = match;
1104		event = buf;
1105		match = NULL;
1106
1107		if (!strlen(sub) || strcmp(sub, "*") == 0)
1108			sub = NULL;
1109		if (!strlen(event) || strcmp(event, "*") == 0)
1110			event = NULL;
1111	}
1112
1113	ret = __ftrace_set_clr_event(tr, match, sub, event, set);
1114
1115	/* Put back the colon to allow this to be called again */
1116	if (buf)
1117		*(buf - 1) = ':';
1118
1119	return ret;
1120}
1121
1122/**
1123 * trace_set_clr_event - enable or disable an event
1124 * @system: system name to match (NULL for any system)
1125 * @event: event name to match (NULL for all events, within system)
1126 * @set: 1 to enable, 0 to disable
1127 *
1128 * This is a way for other parts of the kernel to enable or disable
1129 * event recording.
1130 *
1131 * Returns 0 on success, -EINVAL if the parameters do not match any
1132 * registered events.
1133 */
1134int trace_set_clr_event(const char *system, const char *event, int set)
1135{
1136	struct trace_array *tr = top_trace_array();
1137
1138	if (!tr)
1139		return -ENODEV;
1140
1141	return __ftrace_set_clr_event(tr, NULL, system, event, set);
1142}
1143EXPORT_SYMBOL_GPL(trace_set_clr_event);
1144
1145/**
1146 * trace_array_set_clr_event - enable or disable an event for a trace array.
1147 * @tr: concerned trace array.
1148 * @system: system name to match (NULL for any system)
1149 * @event: event name to match (NULL for all events, within system)
1150 * @enable: true to enable, false to disable
1151 *
1152 * This is a way for other parts of the kernel to enable or disable
1153 * event recording.
1154 *
1155 * Returns 0 on success, -EINVAL if the parameters do not match any
1156 * registered events.
1157 */
1158int trace_array_set_clr_event(struct trace_array *tr, const char *system,
1159		const char *event, bool enable)
1160{
1161	int set;
1162
1163	if (!tr)
1164		return -ENOENT;
1165
1166	set = (enable == true) ? 1 : 0;
1167	return __ftrace_set_clr_event(tr, NULL, system, event, set);
1168}
1169EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
1170
1171/* 128 should be much more than enough */
1172#define EVENT_BUF_SIZE		127
1173
1174static ssize_t
1175ftrace_event_write(struct file *file, const char __user *ubuf,
1176		   size_t cnt, loff_t *ppos)
1177{
1178	struct trace_parser parser;
1179	struct seq_file *m = file->private_data;
1180	struct trace_array *tr = m->private;
1181	ssize_t read, ret;
1182
1183	if (!cnt)
1184		return 0;
1185
1186	ret = tracing_update_buffers();
1187	if (ret < 0)
1188		return ret;
1189
1190	if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
1191		return -ENOMEM;
1192
1193	read = trace_get_user(&parser, ubuf, cnt, ppos);
1194
1195	if (read >= 0 && trace_parser_loaded((&parser))) {
1196		int set = 1;
1197
1198		if (*parser.buffer == '!')
1199			set = 0;
1200
1201		ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
1202		if (ret)
1203			goto out_put;
1204	}
1205
1206	ret = read;
1207
1208 out_put:
1209	trace_parser_put(&parser);
1210
1211	return ret;
1212}
1213
1214static void *
1215t_next(struct seq_file *m, void *v, loff_t *pos)
1216{
1217	struct trace_event_file *file = v;
1218	struct trace_event_call *call;
1219	struct trace_array *tr = m->private;
1220
1221	(*pos)++;
1222
1223	list_for_each_entry_continue(file, &tr->events, list) {
1224		call = file->event_call;
1225		/*
1226		 * The ftrace subsystem is for showing formats only.
1227		 * They can not be enabled or disabled via the event files.
1228		 */
1229		if (call->class && call->class->reg &&
1230		    !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1231			return file;
1232	}
1233
1234	return NULL;
1235}
1236
1237static void *t_start(struct seq_file *m, loff_t *pos)
1238{
1239	struct trace_event_file *file;
1240	struct trace_array *tr = m->private;
1241	loff_t l;
1242
1243	mutex_lock(&event_mutex);
1244
1245	file = list_entry(&tr->events, struct trace_event_file, list);
1246	for (l = 0; l <= *pos; ) {
1247		file = t_next(m, file, &l);
1248		if (!file)
1249			break;
1250	}
1251	return file;
1252}
1253
1254static void *
1255s_next(struct seq_file *m, void *v, loff_t *pos)
1256{
1257	struct trace_event_file *file = v;
1258	struct trace_array *tr = m->private;
1259
1260	(*pos)++;
1261
1262	list_for_each_entry_continue(file, &tr->events, list) {
1263		if (file->flags & EVENT_FILE_FL_ENABLED)
1264			return file;
1265	}
1266
1267	return NULL;
1268}
1269
1270static void *s_start(struct seq_file *m, loff_t *pos)
1271{
1272	struct trace_event_file *file;
1273	struct trace_array *tr = m->private;
1274	loff_t l;
1275
1276	mutex_lock(&event_mutex);
1277
1278	file = list_entry(&tr->events, struct trace_event_file, list);
1279	for (l = 0; l <= *pos; ) {
1280		file = s_next(m, file, &l);
1281		if (!file)
1282			break;
1283	}
1284	return file;
1285}
1286
1287static int t_show(struct seq_file *m, void *v)
1288{
1289	struct trace_event_file *file = v;
1290	struct trace_event_call *call = file->event_call;
1291
1292	if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1293		seq_printf(m, "%s:", call->class->system);
1294	seq_printf(m, "%s\n", trace_event_name(call));
1295
1296	return 0;
1297}
1298
1299static void t_stop(struct seq_file *m, void *p)
1300{
1301	mutex_unlock(&event_mutex);
1302}
1303
1304static void *
1305__next(struct seq_file *m, void *v, loff_t *pos, int type)
1306{
1307	struct trace_array *tr = m->private;
1308	struct trace_pid_list *pid_list;
1309
1310	if (type == TRACE_PIDS)
1311		pid_list = rcu_dereference_sched(tr->filtered_pids);
1312	else
1313		pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1314
1315	return trace_pid_next(pid_list, v, pos);
1316}
1317
1318static void *
1319p_next(struct seq_file *m, void *v, loff_t *pos)
1320{
1321	return __next(m, v, pos, TRACE_PIDS);
1322}
1323
1324static void *
1325np_next(struct seq_file *m, void *v, loff_t *pos)
1326{
1327	return __next(m, v, pos, TRACE_NO_PIDS);
1328}
1329
1330static void *__start(struct seq_file *m, loff_t *pos, int type)
1331	__acquires(RCU)
1332{
1333	struct trace_pid_list *pid_list;
1334	struct trace_array *tr = m->private;
1335
1336	/*
1337	 * Grab the mutex, to keep calls to p_next() having the same
1338	 * tr->filtered_pids as p_start() has.
1339	 * If we just passed the tr->filtered_pids around, then RCU would
1340	 * have been enough, but doing that makes things more complex.
1341	 */
1342	mutex_lock(&event_mutex);
1343	rcu_read_lock_sched();
1344
1345	if (type == TRACE_PIDS)
1346		pid_list = rcu_dereference_sched(tr->filtered_pids);
1347	else
1348		pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1349
1350	if (!pid_list)
1351		return NULL;
1352
1353	return trace_pid_start(pid_list, pos);
1354}
1355
1356static void *p_start(struct seq_file *m, loff_t *pos)
1357	__acquires(RCU)
1358{
1359	return __start(m, pos, TRACE_PIDS);
1360}
1361
1362static void *np_start(struct seq_file *m, loff_t *pos)
1363	__acquires(RCU)
1364{
1365	return __start(m, pos, TRACE_NO_PIDS);
1366}
1367
1368static void p_stop(struct seq_file *m, void *p)
1369	__releases(RCU)
1370{
1371	rcu_read_unlock_sched();
1372	mutex_unlock(&event_mutex);
1373}
1374
1375static ssize_t
1376event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1377		  loff_t *ppos)
1378{
1379	struct trace_event_file *file;
1380	unsigned long flags;
1381	char buf[4] = "0";
1382
1383	mutex_lock(&event_mutex);
1384	file = event_file_data(filp);
1385	if (likely(file))
1386		flags = file->flags;
1387	mutex_unlock(&event_mutex);
1388
1389	if (!file)
1390		return -ENODEV;
1391
1392	if (flags & EVENT_FILE_FL_ENABLED &&
1393	    !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1394		strcpy(buf, "1");
1395
1396	if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1397	    flags & EVENT_FILE_FL_SOFT_MODE)
1398		strcat(buf, "*");
1399
1400	strcat(buf, "\n");
1401
1402	return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1403}
1404
1405static ssize_t
1406event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1407		   loff_t *ppos)
1408{
1409	struct trace_event_file *file;
1410	unsigned long val;
1411	int ret;
1412
1413	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1414	if (ret)
1415		return ret;
1416
1417	ret = tracing_update_buffers();
1418	if (ret < 0)
1419		return ret;
1420
1421	switch (val) {
1422	case 0:
1423	case 1:
1424		ret = -ENODEV;
1425		mutex_lock(&event_mutex);
1426		file = event_file_data(filp);
1427		if (likely(file))
 
 
 
 
 
1428			ret = ftrace_event_enable_disable(file, val);
 
1429		mutex_unlock(&event_mutex);
1430		break;
1431
1432	default:
1433		return -EINVAL;
1434	}
1435
1436	*ppos += cnt;
1437
1438	return ret ? ret : cnt;
1439}
1440
1441static ssize_t
1442system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1443		   loff_t *ppos)
1444{
1445	const char set_to_char[4] = { '?', '0', '1', 'X' };
1446	struct trace_subsystem_dir *dir = filp->private_data;
1447	struct event_subsystem *system = dir->subsystem;
1448	struct trace_event_call *call;
1449	struct trace_event_file *file;
1450	struct trace_array *tr = dir->tr;
1451	char buf[2];
1452	int set = 0;
1453	int ret;
1454
1455	mutex_lock(&event_mutex);
1456	list_for_each_entry(file, &tr->events, list) {
1457		call = file->event_call;
1458		if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1459		    !trace_event_name(call) || !call->class || !call->class->reg)
1460			continue;
1461
1462		if (system && strcmp(call->class->system, system->name) != 0)
1463			continue;
1464
1465		/*
1466		 * We need to find out if all the events are set
1467		 * or if all events or cleared, or if we have
1468		 * a mixture.
1469		 */
1470		set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1471
1472		/*
1473		 * If we have a mixture, no need to look further.
1474		 */
1475		if (set == 3)
1476			break;
1477	}
1478	mutex_unlock(&event_mutex);
1479
1480	buf[0] = set_to_char[set];
1481	buf[1] = '\n';
1482
1483	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1484
1485	return ret;
1486}
1487
1488static ssize_t
1489system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1490		    loff_t *ppos)
1491{
1492	struct trace_subsystem_dir *dir = filp->private_data;
1493	struct event_subsystem *system = dir->subsystem;
1494	const char *name = NULL;
1495	unsigned long val;
1496	ssize_t ret;
1497
1498	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1499	if (ret)
1500		return ret;
1501
1502	ret = tracing_update_buffers();
1503	if (ret < 0)
1504		return ret;
1505
1506	if (val != 0 && val != 1)
1507		return -EINVAL;
1508
1509	/*
1510	 * Opening of "enable" adds a ref count to system,
1511	 * so the name is safe to use.
1512	 */
1513	if (system)
1514		name = system->name;
1515
1516	ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1517	if (ret)
1518		goto out;
1519
1520	ret = cnt;
1521
1522out:
1523	*ppos += cnt;
1524
1525	return ret;
1526}
1527
1528enum {
1529	FORMAT_HEADER		= 1,
1530	FORMAT_FIELD_SEPERATOR	= 2,
1531	FORMAT_PRINTFMT		= 3,
1532};
1533
1534static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1535{
1536	struct trace_event_call *call = event_file_data(m->private);
 
1537	struct list_head *common_head = &ftrace_common_fields;
1538	struct list_head *head = trace_get_fields(call);
1539	struct list_head *node = v;
1540
1541	(*pos)++;
1542
1543	switch ((unsigned long)v) {
1544	case FORMAT_HEADER:
1545		node = common_head;
1546		break;
1547
1548	case FORMAT_FIELD_SEPERATOR:
1549		node = head;
1550		break;
1551
1552	case FORMAT_PRINTFMT:
1553		/* all done */
1554		return NULL;
1555	}
1556
1557	node = node->prev;
1558	if (node == common_head)
1559		return (void *)FORMAT_FIELD_SEPERATOR;
1560	else if (node == head)
1561		return (void *)FORMAT_PRINTFMT;
1562	else
1563		return node;
1564}
1565
1566static int f_show(struct seq_file *m, void *v)
1567{
1568	struct trace_event_call *call = event_file_data(m->private);
 
1569	struct ftrace_event_field *field;
1570	const char *array_descriptor;
1571
1572	switch ((unsigned long)v) {
1573	case FORMAT_HEADER:
1574		seq_printf(m, "name: %s\n", trace_event_name(call));
1575		seq_printf(m, "ID: %d\n", call->event.type);
1576		seq_puts(m, "format:\n");
1577		return 0;
1578
1579	case FORMAT_FIELD_SEPERATOR:
1580		seq_putc(m, '\n');
1581		return 0;
1582
1583	case FORMAT_PRINTFMT:
1584		seq_printf(m, "\nprint fmt: %s\n",
1585			   call->print_fmt);
1586		return 0;
1587	}
1588
1589	field = list_entry(v, struct ftrace_event_field, link);
1590	/*
1591	 * Smartly shows the array type(except dynamic array).
1592	 * Normal:
1593	 *	field:TYPE VAR
1594	 * If TYPE := TYPE[LEN], it is shown:
1595	 *	field:TYPE VAR[LEN]
1596	 */
1597	array_descriptor = strchr(field->type, '[');
1598
1599	if (str_has_prefix(field->type, "__data_loc"))
1600		array_descriptor = NULL;
1601
1602	if (!array_descriptor)
1603		seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1604			   field->type, field->name, field->offset,
1605			   field->size, !!field->is_signed);
1606	else if (field->len)
1607		seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1608			   (int)(array_descriptor - field->type),
1609			   field->type, field->name,
1610			   field->len, field->offset,
1611			   field->size, !!field->is_signed);
1612	else
1613		seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1614				(int)(array_descriptor - field->type),
1615				field->type, field->name,
1616				field->offset, field->size, !!field->is_signed);
1617
1618	return 0;
1619}
1620
1621static void *f_start(struct seq_file *m, loff_t *pos)
1622{
 
1623	void *p = (void *)FORMAT_HEADER;
1624	loff_t l = 0;
1625
1626	/* ->stop() is called even if ->start() fails */
1627	mutex_lock(&event_mutex);
1628	if (!event_file_data(m->private))
 
1629		return ERR_PTR(-ENODEV);
1630
1631	while (l < *pos && p)
1632		p = f_next(m, p, &l);
1633
1634	return p;
1635}
1636
1637static void f_stop(struct seq_file *m, void *p)
1638{
1639	mutex_unlock(&event_mutex);
1640}
1641
1642static const struct seq_operations trace_format_seq_ops = {
1643	.start		= f_start,
1644	.next		= f_next,
1645	.stop		= f_stop,
1646	.show		= f_show,
1647};
1648
1649static int trace_format_open(struct inode *inode, struct file *file)
1650{
1651	struct seq_file *m;
1652	int ret;
1653
1654	/* Do we want to hide event format files on tracefs lockdown? */
1655
1656	ret = seq_open(file, &trace_format_seq_ops);
1657	if (ret < 0)
1658		return ret;
1659
1660	m = file->private_data;
1661	m->private = file;
1662
1663	return 0;
1664}
1665
 
1666static ssize_t
1667event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1668{
1669	int id = (long)event_file_data(filp);
1670	char buf[32];
1671	int len;
1672
1673	if (unlikely(!id))
1674		return -ENODEV;
1675
1676	len = sprintf(buf, "%d\n", id);
1677
1678	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1679}
 
1680
1681static ssize_t
1682event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1683		  loff_t *ppos)
1684{
1685	struct trace_event_file *file;
1686	struct trace_seq *s;
1687	int r = -ENODEV;
1688
1689	if (*ppos)
1690		return 0;
1691
1692	s = kmalloc(sizeof(*s), GFP_KERNEL);
1693
1694	if (!s)
1695		return -ENOMEM;
1696
1697	trace_seq_init(s);
1698
1699	mutex_lock(&event_mutex);
1700	file = event_file_data(filp);
1701	if (file)
1702		print_event_filter(file, s);
1703	mutex_unlock(&event_mutex);
1704
1705	if (file)
1706		r = simple_read_from_buffer(ubuf, cnt, ppos,
1707					    s->buffer, trace_seq_used(s));
1708
1709	kfree(s);
1710
1711	return r;
1712}
1713
1714static ssize_t
1715event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1716		   loff_t *ppos)
1717{
1718	struct trace_event_file *file;
1719	char *buf;
1720	int err = -ENODEV;
1721
1722	if (cnt >= PAGE_SIZE)
1723		return -EINVAL;
1724
1725	buf = memdup_user_nul(ubuf, cnt);
1726	if (IS_ERR(buf))
1727		return PTR_ERR(buf);
1728
1729	mutex_lock(&event_mutex);
1730	file = event_file_data(filp);
1731	if (file)
1732		err = apply_event_filter(file, buf);
 
 
 
 
1733	mutex_unlock(&event_mutex);
1734
1735	kfree(buf);
1736	if (err < 0)
1737		return err;
1738
1739	*ppos += cnt;
1740
1741	return cnt;
1742}
1743
1744static LIST_HEAD(event_subsystems);
1745
1746static int subsystem_open(struct inode *inode, struct file *filp)
1747{
1748	struct trace_subsystem_dir *dir = NULL, *iter_dir;
1749	struct trace_array *tr = NULL, *iter_tr;
1750	struct event_subsystem *system = NULL;
1751	int ret;
1752
1753	if (tracing_is_disabled())
1754		return -ENODEV;
1755
1756	/* Make sure the system still exists */
1757	mutex_lock(&event_mutex);
1758	mutex_lock(&trace_types_lock);
1759	list_for_each_entry(iter_tr, &ftrace_trace_arrays, list) {
1760		list_for_each_entry(iter_dir, &iter_tr->systems, list) {
1761			if (iter_dir == inode->i_private) {
1762				/* Don't open systems with no events */
1763				tr = iter_tr;
1764				dir = iter_dir;
1765				if (dir->nr_events) {
1766					__get_system_dir(dir);
1767					system = dir->subsystem;
1768				}
1769				goto exit_loop;
1770			}
1771		}
1772	}
1773 exit_loop:
1774	mutex_unlock(&trace_types_lock);
1775	mutex_unlock(&event_mutex);
1776
1777	if (!system)
1778		return -ENODEV;
1779
1780	/* Still need to increment the ref count of the system */
1781	if (trace_array_get(tr) < 0) {
1782		put_system(dir);
1783		return -ENODEV;
1784	}
1785
1786	ret = tracing_open_generic(inode, filp);
1787	if (ret < 0) {
1788		trace_array_put(tr);
1789		put_system(dir);
1790	}
1791
1792	return ret;
1793}
1794
1795static int system_tr_open(struct inode *inode, struct file *filp)
1796{
1797	struct trace_subsystem_dir *dir;
1798	struct trace_array *tr = inode->i_private;
1799	int ret;
1800
1801	/* Make a temporary dir that has no system but points to tr */
1802	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1803	if (!dir)
1804		return -ENOMEM;
1805
1806	ret = tracing_open_generic_tr(inode, filp);
1807	if (ret < 0) {
1808		kfree(dir);
1809		return ret;
1810	}
1811	dir->tr = tr;
1812	filp->private_data = dir;
1813
1814	return 0;
1815}
1816
1817static int subsystem_release(struct inode *inode, struct file *file)
1818{
1819	struct trace_subsystem_dir *dir = file->private_data;
1820
1821	trace_array_put(dir->tr);
1822
1823	/*
1824	 * If dir->subsystem is NULL, then this is a temporary
1825	 * descriptor that was made for a trace_array to enable
1826	 * all subsystems.
1827	 */
1828	if (dir->subsystem)
1829		put_system(dir);
1830	else
1831		kfree(dir);
1832
1833	return 0;
1834}
1835
1836static ssize_t
1837subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1838		      loff_t *ppos)
1839{
1840	struct trace_subsystem_dir *dir = filp->private_data;
1841	struct event_subsystem *system = dir->subsystem;
1842	struct trace_seq *s;
1843	int r;
1844
1845	if (*ppos)
1846		return 0;
1847
1848	s = kmalloc(sizeof(*s), GFP_KERNEL);
1849	if (!s)
1850		return -ENOMEM;
1851
1852	trace_seq_init(s);
1853
1854	print_subsystem_event_filter(system, s);
1855	r = simple_read_from_buffer(ubuf, cnt, ppos,
1856				    s->buffer, trace_seq_used(s));
1857
1858	kfree(s);
1859
1860	return r;
1861}
1862
1863static ssize_t
1864subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1865		       loff_t *ppos)
1866{
1867	struct trace_subsystem_dir *dir = filp->private_data;
1868	char *buf;
1869	int err;
1870
1871	if (cnt >= PAGE_SIZE)
1872		return -EINVAL;
1873
1874	buf = memdup_user_nul(ubuf, cnt);
1875	if (IS_ERR(buf))
1876		return PTR_ERR(buf);
1877
1878	err = apply_subsystem_event_filter(dir, buf);
1879	kfree(buf);
1880	if (err < 0)
1881		return err;
1882
1883	*ppos += cnt;
1884
1885	return cnt;
1886}
1887
1888static ssize_t
1889show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1890{
1891	int (*func)(struct trace_seq *s) = filp->private_data;
1892	struct trace_seq *s;
1893	int r;
1894
1895	if (*ppos)
1896		return 0;
1897
1898	s = kmalloc(sizeof(*s), GFP_KERNEL);
1899	if (!s)
1900		return -ENOMEM;
1901
1902	trace_seq_init(s);
1903
1904	func(s);
1905	r = simple_read_from_buffer(ubuf, cnt, ppos,
1906				    s->buffer, trace_seq_used(s));
1907
1908	kfree(s);
1909
1910	return r;
1911}
1912
1913static void ignore_task_cpu(void *data)
1914{
1915	struct trace_array *tr = data;
1916	struct trace_pid_list *pid_list;
1917	struct trace_pid_list *no_pid_list;
1918
1919	/*
1920	 * This function is called by on_each_cpu() while the
1921	 * event_mutex is held.
1922	 */
1923	pid_list = rcu_dereference_protected(tr->filtered_pids,
1924					     mutex_is_locked(&event_mutex));
1925	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1926					     mutex_is_locked(&event_mutex));
1927
1928	this_cpu_write(tr->array_buffer.data->ignore_pid,
1929		       trace_ignore_this_task(pid_list, no_pid_list, current));
1930}
1931
1932static void register_pid_events(struct trace_array *tr)
1933{
1934	/*
1935	 * Register a probe that is called before all other probes
1936	 * to set ignore_pid if next or prev do not match.
1937	 * Register a probe this is called after all other probes
1938	 * to only keep ignore_pid set if next pid matches.
1939	 */
1940	register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1941					 tr, INT_MAX);
1942	register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1943					 tr, 0);
1944
1945	register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1946					 tr, INT_MAX);
1947	register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1948					 tr, 0);
1949
1950	register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1951					     tr, INT_MAX);
1952	register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1953					     tr, 0);
1954
1955	register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1956					 tr, INT_MAX);
1957	register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1958					 tr, 0);
1959}
1960
1961static ssize_t
1962event_pid_write(struct file *filp, const char __user *ubuf,
1963		size_t cnt, loff_t *ppos, int type)
1964{
1965	struct seq_file *m = filp->private_data;
1966	struct trace_array *tr = m->private;
1967	struct trace_pid_list *filtered_pids = NULL;
1968	struct trace_pid_list *other_pids = NULL;
1969	struct trace_pid_list *pid_list;
1970	struct trace_event_file *file;
1971	ssize_t ret;
1972
1973	if (!cnt)
1974		return 0;
1975
1976	ret = tracing_update_buffers();
1977	if (ret < 0)
1978		return ret;
1979
1980	mutex_lock(&event_mutex);
1981
1982	if (type == TRACE_PIDS) {
1983		filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1984							  lockdep_is_held(&event_mutex));
1985		other_pids = rcu_dereference_protected(tr->filtered_no_pids,
1986							  lockdep_is_held(&event_mutex));
1987	} else {
1988		filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
1989							  lockdep_is_held(&event_mutex));
1990		other_pids = rcu_dereference_protected(tr->filtered_pids,
1991							  lockdep_is_held(&event_mutex));
1992	}
1993
1994	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1995	if (ret < 0)
1996		goto out;
1997
1998	if (type == TRACE_PIDS)
1999		rcu_assign_pointer(tr->filtered_pids, pid_list);
2000	else
2001		rcu_assign_pointer(tr->filtered_no_pids, pid_list);
2002
2003	list_for_each_entry(file, &tr->events, list) {
2004		set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
2005	}
2006
2007	if (filtered_pids) {
2008		tracepoint_synchronize_unregister();
2009		trace_pid_list_free(filtered_pids);
2010	} else if (pid_list && !other_pids) {
2011		register_pid_events(tr);
2012	}
2013
2014	/*
2015	 * Ignoring of pids is done at task switch. But we have to
2016	 * check for those tasks that are currently running.
2017	 * Always do this in case a pid was appended or removed.
2018	 */
2019	on_each_cpu(ignore_task_cpu, tr, 1);
2020
2021 out:
2022	mutex_unlock(&event_mutex);
2023
2024	if (ret > 0)
2025		*ppos += ret;
2026
2027	return ret;
2028}
2029
2030static ssize_t
2031ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
2032		       size_t cnt, loff_t *ppos)
2033{
2034	return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
2035}
2036
2037static ssize_t
2038ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
2039			size_t cnt, loff_t *ppos)
2040{
2041	return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
2042}
2043
2044static int ftrace_event_avail_open(struct inode *inode, struct file *file);
2045static int ftrace_event_set_open(struct inode *inode, struct file *file);
2046static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
2047static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
2048static int ftrace_event_release(struct inode *inode, struct file *file);
2049
2050static const struct seq_operations show_event_seq_ops = {
2051	.start = t_start,
2052	.next = t_next,
2053	.show = t_show,
2054	.stop = t_stop,
2055};
2056
2057static const struct seq_operations show_set_event_seq_ops = {
2058	.start = s_start,
2059	.next = s_next,
2060	.show = t_show,
2061	.stop = t_stop,
2062};
2063
2064static const struct seq_operations show_set_pid_seq_ops = {
2065	.start = p_start,
2066	.next = p_next,
2067	.show = trace_pid_show,
2068	.stop = p_stop,
2069};
2070
2071static const struct seq_operations show_set_no_pid_seq_ops = {
2072	.start = np_start,
2073	.next = np_next,
2074	.show = trace_pid_show,
2075	.stop = p_stop,
2076};
2077
2078static const struct file_operations ftrace_avail_fops = {
2079	.open = ftrace_event_avail_open,
2080	.read = seq_read,
2081	.llseek = seq_lseek,
2082	.release = seq_release,
2083};
2084
2085static const struct file_operations ftrace_set_event_fops = {
2086	.open = ftrace_event_set_open,
2087	.read = seq_read,
2088	.write = ftrace_event_write,
2089	.llseek = seq_lseek,
2090	.release = ftrace_event_release,
2091};
2092
2093static const struct file_operations ftrace_set_event_pid_fops = {
2094	.open = ftrace_event_set_pid_open,
2095	.read = seq_read,
2096	.write = ftrace_event_pid_write,
2097	.llseek = seq_lseek,
2098	.release = ftrace_event_release,
2099};
2100
2101static const struct file_operations ftrace_set_event_notrace_pid_fops = {
2102	.open = ftrace_event_set_npid_open,
2103	.read = seq_read,
2104	.write = ftrace_event_npid_write,
2105	.llseek = seq_lseek,
2106	.release = ftrace_event_release,
2107};
2108
2109static const struct file_operations ftrace_enable_fops = {
2110	.open = tracing_open_generic,
2111	.read = event_enable_read,
2112	.write = event_enable_write,
 
2113	.llseek = default_llseek,
2114};
2115
2116static const struct file_operations ftrace_event_format_fops = {
2117	.open = trace_format_open,
2118	.read = seq_read,
2119	.llseek = seq_lseek,
2120	.release = seq_release,
2121};
2122
 
2123static const struct file_operations ftrace_event_id_fops = {
2124	.read = event_id_read,
2125	.llseek = default_llseek,
2126};
 
2127
2128static const struct file_operations ftrace_event_filter_fops = {
2129	.open = tracing_open_generic,
2130	.read = event_filter_read,
2131	.write = event_filter_write,
 
2132	.llseek = default_llseek,
2133};
2134
2135static const struct file_operations ftrace_subsystem_filter_fops = {
2136	.open = subsystem_open,
2137	.read = subsystem_filter_read,
2138	.write = subsystem_filter_write,
2139	.llseek = default_llseek,
2140	.release = subsystem_release,
2141};
2142
2143static const struct file_operations ftrace_system_enable_fops = {
2144	.open = subsystem_open,
2145	.read = system_enable_read,
2146	.write = system_enable_write,
2147	.llseek = default_llseek,
2148	.release = subsystem_release,
2149};
2150
2151static const struct file_operations ftrace_tr_enable_fops = {
2152	.open = system_tr_open,
2153	.read = system_enable_read,
2154	.write = system_enable_write,
2155	.llseek = default_llseek,
2156	.release = subsystem_release,
2157};
2158
2159static const struct file_operations ftrace_show_header_fops = {
2160	.open = tracing_open_generic,
2161	.read = show_header,
2162	.llseek = default_llseek,
 
 
 
 
 
 
 
 
2163};
2164
2165static int
2166ftrace_event_open(struct inode *inode, struct file *file,
2167		  const struct seq_operations *seq_ops)
2168{
2169	struct seq_file *m;
2170	int ret;
2171
2172	ret = security_locked_down(LOCKDOWN_TRACEFS);
2173	if (ret)
2174		return ret;
2175
2176	ret = seq_open(file, seq_ops);
2177	if (ret < 0)
2178		return ret;
2179	m = file->private_data;
2180	/* copy tr over to seq ops */
2181	m->private = inode->i_private;
2182
2183	return ret;
2184}
2185
2186static int ftrace_event_release(struct inode *inode, struct file *file)
2187{
2188	struct trace_array *tr = inode->i_private;
2189
2190	trace_array_put(tr);
2191
2192	return seq_release(inode, file);
2193}
2194
2195static int
2196ftrace_event_avail_open(struct inode *inode, struct file *file)
2197{
2198	const struct seq_operations *seq_ops = &show_event_seq_ops;
2199
2200	/* Checks for tracefs lockdown */
2201	return ftrace_event_open(inode, file, seq_ops);
2202}
2203
2204static int
2205ftrace_event_set_open(struct inode *inode, struct file *file)
2206{
2207	const struct seq_operations *seq_ops = &show_set_event_seq_ops;
2208	struct trace_array *tr = inode->i_private;
2209	int ret;
2210
2211	ret = tracing_check_open_get_tr(tr);
2212	if (ret)
2213		return ret;
2214
2215	if ((file->f_mode & FMODE_WRITE) &&
2216	    (file->f_flags & O_TRUNC))
2217		ftrace_clear_events(tr);
2218
2219	ret = ftrace_event_open(inode, file, seq_ops);
2220	if (ret < 0)
2221		trace_array_put(tr);
2222	return ret;
2223}
2224
2225static int
2226ftrace_event_set_pid_open(struct inode *inode, struct file *file)
2227{
2228	const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
2229	struct trace_array *tr = inode->i_private;
2230	int ret;
2231
2232	ret = tracing_check_open_get_tr(tr);
2233	if (ret)
2234		return ret;
2235
2236	if ((file->f_mode & FMODE_WRITE) &&
2237	    (file->f_flags & O_TRUNC))
2238		ftrace_clear_event_pids(tr, TRACE_PIDS);
2239
2240	ret = ftrace_event_open(inode, file, seq_ops);
2241	if (ret < 0)
2242		trace_array_put(tr);
2243	return ret;
2244}
2245
2246static int
2247ftrace_event_set_npid_open(struct inode *inode, struct file *file)
2248{
2249	const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2250	struct trace_array *tr = inode->i_private;
2251	int ret;
2252
2253	ret = tracing_check_open_get_tr(tr);
2254	if (ret)
2255		return ret;
2256
2257	if ((file->f_mode & FMODE_WRITE) &&
2258	    (file->f_flags & O_TRUNC))
2259		ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2260
2261	ret = ftrace_event_open(inode, file, seq_ops);
2262	if (ret < 0)
2263		trace_array_put(tr);
2264	return ret;
2265}
2266
2267static struct event_subsystem *
2268create_new_subsystem(const char *name)
2269{
2270	struct event_subsystem *system;
2271
2272	/* need to create new entry */
2273	system = kmalloc(sizeof(*system), GFP_KERNEL);
2274	if (!system)
2275		return NULL;
2276
2277	system->ref_count = 1;
2278
2279	/* Only allocate if dynamic (kprobes and modules) */
2280	system->name = kstrdup_const(name, GFP_KERNEL);
2281	if (!system->name)
2282		goto out_free;
2283
2284	system->filter = NULL;
2285
2286	system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2287	if (!system->filter)
2288		goto out_free;
2289
2290	list_add(&system->list, &event_subsystems);
2291
2292	return system;
2293
2294 out_free:
2295	kfree_const(system->name);
2296	kfree(system);
2297	return NULL;
2298}
2299
2300static struct dentry *
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2301event_subsystem_dir(struct trace_array *tr, const char *name,
2302		    struct trace_event_file *file, struct dentry *parent)
2303{
2304	struct event_subsystem *system, *iter;
2305	struct trace_subsystem_dir *dir;
2306	struct dentry *entry;
 
 
 
 
 
 
 
 
 
 
 
2307
2308	/* First see if we did not already create this dir */
2309	list_for_each_entry(dir, &tr->systems, list) {
2310		system = dir->subsystem;
2311		if (strcmp(system->name, name) == 0) {
2312			dir->nr_events++;
2313			file->system = dir;
2314			return dir->entry;
2315		}
2316	}
2317
2318	/* Now see if the system itself exists. */
2319	system = NULL;
2320	list_for_each_entry(iter, &event_subsystems, list) {
2321		if (strcmp(iter->name, name) == 0) {
2322			system = iter;
2323			break;
2324		}
2325	}
2326
2327	dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2328	if (!dir)
2329		goto out_fail;
2330
2331	if (!system) {
2332		system = create_new_subsystem(name);
2333		if (!system)
2334			goto out_free;
2335	} else
2336		__get_system(system);
2337
2338	dir->entry = tracefs_create_dir(name, parent);
2339	if (!dir->entry) {
 
 
 
 
 
 
2340		pr_warn("Failed to create system directory %s\n", name);
2341		__put_system(system);
2342		goto out_free;
2343	}
2344
 
2345	dir->tr = tr;
2346	dir->ref_count = 1;
2347	dir->nr_events = 1;
2348	dir->subsystem = system;
2349	file->system = dir;
2350
2351	/* the ftrace system is special, do not create enable or filter files */
2352	if (strcmp(name, "ftrace") != 0) {
2353
2354		entry = tracefs_create_file("filter", TRACE_MODE_WRITE,
2355					    dir->entry, dir,
2356					    &ftrace_subsystem_filter_fops);
2357		if (!entry) {
2358			kfree(system->filter);
2359			system->filter = NULL;
2360			pr_warn("Could not create tracefs '%s/filter' entry\n", name);
2361		}
2362
2363		trace_create_file("enable", TRACE_MODE_WRITE, dir->entry, dir,
2364				  &ftrace_system_enable_fops);
2365	}
2366
2367	list_add(&dir->list, &tr->systems);
2368
2369	return dir->entry;
2370
2371 out_free:
2372	kfree(dir);
2373 out_fail:
2374	/* Only print this message if failed on memory allocation */
2375	if (!dir || !system)
2376		pr_warn("No memory to create event subsystem %s\n", name);
2377	return NULL;
2378}
2379
2380static int
2381event_define_fields(struct trace_event_call *call)
2382{
2383	struct list_head *head;
2384	int ret = 0;
2385
2386	/*
2387	 * Other events may have the same class. Only update
2388	 * the fields if they are not already defined.
2389	 */
2390	head = trace_get_fields(call);
2391	if (list_empty(head)) {
2392		struct trace_event_fields *field = call->class->fields_array;
2393		unsigned int offset = sizeof(struct trace_entry);
2394
2395		for (; field->type; field++) {
2396			if (field->type == TRACE_FUNCTION_TYPE) {
2397				field->define_fields(call);
2398				break;
2399			}
2400
2401			offset = ALIGN(offset, field->align);
2402			ret = trace_define_field_ext(call, field->type, field->name,
2403						 offset, field->size,
2404						 field->is_signed, field->filter_type,
2405						 field->len);
2406			if (WARN_ON_ONCE(ret)) {
2407				pr_err("error code is %d\n", ret);
2408				break;
2409			}
2410
2411			offset += field->size;
2412		}
2413	}
2414
2415	return ret;
2416}
2417
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2418static int
2419event_create_dir(struct dentry *parent, struct trace_event_file *file)
2420{
2421	struct trace_event_call *call = file->event_call;
2422	struct trace_array *tr = file->tr;
2423	struct dentry *d_events;
 
2424	const char *name;
 
2425	int ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2426
2427	/*
2428	 * If the trace point header did not define TRACE_SYSTEM
2429	 * then the system would be called "TRACE_SYSTEM".
 
2430	 */
2431	if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
2432		d_events = event_subsystem_dir(tr, call->class->system, file, parent);
2433		if (!d_events)
2434			return -ENOMEM;
2435	} else
2436		d_events = parent;
 
 
2437
2438	name = trace_event_name(call);
2439	file->dir = tracefs_create_dir(name, d_events);
2440	if (!file->dir) {
2441		pr_warn("Could not create tracefs '%s' directory\n", name);
2442		return -1;
2443	}
2444
2445	if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2446		trace_create_file("enable", TRACE_MODE_WRITE, file->dir, file,
2447				  &ftrace_enable_fops);
2448
2449#ifdef CONFIG_PERF_EVENTS
2450	if (call->event.type && call->class->reg)
2451		trace_create_file("id", TRACE_MODE_READ, file->dir,
2452				  (void *)(long)call->event.type,
2453				  &ftrace_event_id_fops);
2454#endif
2455
2456	ret = event_define_fields(call);
2457	if (ret < 0) {
2458		pr_warn("Could not initialize trace point events/%s\n", name);
2459		return ret;
2460	}
2461
2462	/*
2463	 * Only event directories that can be enabled should have
2464	 * triggers or filters.
2465	 */
2466	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2467		trace_create_file("filter", TRACE_MODE_WRITE, file->dir,
2468				  file, &ftrace_event_filter_fops);
2469
2470		trace_create_file("trigger", TRACE_MODE_WRITE, file->dir,
2471				  file, &event_trigger_fops);
2472	}
2473
2474#ifdef CONFIG_HIST_TRIGGERS
2475	trace_create_file("hist", TRACE_MODE_READ, file->dir, file,
2476			  &event_hist_fops);
2477#endif
2478#ifdef CONFIG_HIST_TRIGGERS_DEBUG
2479	trace_create_file("hist_debug", TRACE_MODE_READ, file->dir, file,
2480			  &event_hist_debug_fops);
2481#endif
2482	trace_create_file("format", TRACE_MODE_READ, file->dir, call,
2483			  &ftrace_event_format_fops);
2484
2485#ifdef CONFIG_TRACE_EVENT_INJECT
2486	if (call->event.type && call->class->reg)
2487		trace_create_file("inject", 0200, file->dir, file,
2488				  &event_inject_fops);
2489#endif
2490
2491	return 0;
2492}
2493
2494static void remove_event_from_tracers(struct trace_event_call *call)
2495{
2496	struct trace_event_file *file;
2497	struct trace_array *tr;
2498
2499	do_for_each_event_file_safe(tr, file) {
2500		if (file->event_call != call)
2501			continue;
2502
2503		remove_event_file_dir(file);
2504		/*
2505		 * The do_for_each_event_file_safe() is
2506		 * a double loop. After finding the call for this
2507		 * trace_array, we use break to jump to the next
2508		 * trace_array.
2509		 */
2510		break;
2511	} while_for_each_event_file();
2512}
2513
2514static void event_remove(struct trace_event_call *call)
2515{
2516	struct trace_array *tr;
2517	struct trace_event_file *file;
2518
2519	do_for_each_event_file(tr, file) {
2520		if (file->event_call != call)
2521			continue;
2522
2523		if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2524			tr->clear_trace = true;
2525
2526		ftrace_event_enable_disable(file, 0);
2527		/*
2528		 * The do_for_each_event_file() is
2529		 * a double loop. After finding the call for this
2530		 * trace_array, we use break to jump to the next
2531		 * trace_array.
2532		 */
2533		break;
2534	} while_for_each_event_file();
2535
2536	if (call->event.funcs)
2537		__unregister_trace_event(&call->event);
2538	remove_event_from_tracers(call);
2539	list_del(&call->list);
2540}
2541
2542static int event_init(struct trace_event_call *call)
2543{
2544	int ret = 0;
2545	const char *name;
2546
2547	name = trace_event_name(call);
2548	if (WARN_ON(!name))
2549		return -EINVAL;
2550
2551	if (call->class->raw_init) {
2552		ret = call->class->raw_init(call);
2553		if (ret < 0 && ret != -ENOSYS)
2554			pr_warn("Could not initialize trace events/%s\n", name);
2555	}
2556
2557	return ret;
2558}
2559
2560static int
2561__register_event(struct trace_event_call *call, struct module *mod)
2562{
2563	int ret;
2564
2565	ret = event_init(call);
2566	if (ret < 0)
2567		return ret;
2568
2569	list_add(&call->list, &ftrace_events);
2570	if (call->flags & TRACE_EVENT_FL_DYNAMIC)
2571		atomic_set(&call->refcnt, 0);
2572	else
2573		call->module = mod;
2574
2575	return 0;
2576}
2577
2578static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2579{
2580	int rlen;
2581	int elen;
2582
2583	/* Find the length of the eval value as a string */
2584	elen = snprintf(ptr, 0, "%ld", map->eval_value);
2585	/* Make sure there's enough room to replace the string with the value */
2586	if (len < elen)
2587		return NULL;
2588
2589	snprintf(ptr, elen + 1, "%ld", map->eval_value);
2590
2591	/* Get the rest of the string of ptr */
2592	rlen = strlen(ptr + len);
2593	memmove(ptr + elen, ptr + len, rlen);
2594	/* Make sure we end the new string */
2595	ptr[elen + rlen] = 0;
2596
2597	return ptr + elen;
2598}
2599
2600static void update_event_printk(struct trace_event_call *call,
2601				struct trace_eval_map *map)
2602{
2603	char *ptr;
2604	int quote = 0;
2605	int len = strlen(map->eval_string);
2606
2607	for (ptr = call->print_fmt; *ptr; ptr++) {
2608		if (*ptr == '\\') {
2609			ptr++;
2610			/* paranoid */
2611			if (!*ptr)
2612				break;
2613			continue;
2614		}
2615		if (*ptr == '"') {
2616			quote ^= 1;
2617			continue;
2618		}
2619		if (quote)
2620			continue;
2621		if (isdigit(*ptr)) {
2622			/* skip numbers */
2623			do {
2624				ptr++;
2625				/* Check for alpha chars like ULL */
2626			} while (isalnum(*ptr));
2627			if (!*ptr)
2628				break;
2629			/*
2630			 * A number must have some kind of delimiter after
2631			 * it, and we can ignore that too.
2632			 */
2633			continue;
2634		}
2635		if (isalpha(*ptr) || *ptr == '_') {
2636			if (strncmp(map->eval_string, ptr, len) == 0 &&
2637			    !isalnum(ptr[len]) && ptr[len] != '_') {
2638				ptr = eval_replace(ptr, map, len);
2639				/* enum/sizeof string smaller than value */
2640				if (WARN_ON_ONCE(!ptr))
2641					return;
2642				/*
2643				 * No need to decrement here, as eval_replace()
2644				 * returns the pointer to the character passed
2645				 * the eval, and two evals can not be placed
2646				 * back to back without something in between.
2647				 * We can skip that something in between.
2648				 */
2649				continue;
2650			}
2651		skip_more:
2652			do {
2653				ptr++;
2654			} while (isalnum(*ptr) || *ptr == '_');
2655			if (!*ptr)
2656				break;
2657			/*
2658			 * If what comes after this variable is a '.' or
2659			 * '->' then we can continue to ignore that string.
2660			 */
2661			if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2662				ptr += *ptr == '.' ? 1 : 2;
2663				if (!*ptr)
2664					break;
2665				goto skip_more;
2666			}
2667			/*
2668			 * Once again, we can skip the delimiter that came
2669			 * after the string.
2670			 */
2671			continue;
2672		}
2673	}
2674}
2675
2676static void add_str_to_module(struct module *module, char *str)
2677{
2678	struct module_string *modstr;
2679
2680	modstr = kmalloc(sizeof(*modstr), GFP_KERNEL);
2681
2682	/*
2683	 * If we failed to allocate memory here, then we'll just
2684	 * let the str memory leak when the module is removed.
2685	 * If this fails to allocate, there's worse problems than
2686	 * a leaked string on module removal.
2687	 */
2688	if (WARN_ON_ONCE(!modstr))
2689		return;
2690
2691	modstr->module = module;
2692	modstr->str = str;
2693
2694	list_add(&modstr->next, &module_strings);
2695}
2696
2697static void update_event_fields(struct trace_event_call *call,
2698				struct trace_eval_map *map)
2699{
2700	struct ftrace_event_field *field;
2701	struct list_head *head;
2702	char *ptr;
2703	char *str;
2704	int len = strlen(map->eval_string);
2705
2706	/* Dynamic events should never have field maps */
2707	if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC))
2708		return;
2709
2710	head = trace_get_fields(call);
2711	list_for_each_entry(field, head, link) {
2712		ptr = strchr(field->type, '[');
2713		if (!ptr)
2714			continue;
2715		ptr++;
2716
2717		if (!isalpha(*ptr) && *ptr != '_')
2718			continue;
2719
2720		if (strncmp(map->eval_string, ptr, len) != 0)
2721			continue;
2722
2723		str = kstrdup(field->type, GFP_KERNEL);
2724		if (WARN_ON_ONCE(!str))
2725			return;
2726		ptr = str + (ptr - field->type);
2727		ptr = eval_replace(ptr, map, len);
2728		/* enum/sizeof string smaller than value */
2729		if (WARN_ON_ONCE(!ptr)) {
2730			kfree(str);
2731			continue;
2732		}
2733
2734		/*
2735		 * If the event is part of a module, then we need to free the string
2736		 * when the module is removed. Otherwise, it will stay allocated
2737		 * until a reboot.
2738		 */
2739		if (call->module)
2740			add_str_to_module(call->module, str);
2741
2742		field->type = str;
2743	}
2744}
2745
2746void trace_event_eval_update(struct trace_eval_map **map, int len)
2747{
2748	struct trace_event_call *call, *p;
2749	const char *last_system = NULL;
2750	bool first = false;
2751	int last_i;
2752	int i;
2753
2754	down_write(&trace_event_sem);
2755	list_for_each_entry_safe(call, p, &ftrace_events, list) {
2756		/* events are usually grouped together with systems */
2757		if (!last_system || call->class->system != last_system) {
2758			first = true;
2759			last_i = 0;
2760			last_system = call->class->system;
2761		}
2762
2763		/*
2764		 * Since calls are grouped by systems, the likelihood that the
2765		 * next call in the iteration belongs to the same system as the
2766		 * previous call is high. As an optimization, we skip searching
2767		 * for a map[] that matches the call's system if the last call
2768		 * was from the same system. That's what last_i is for. If the
2769		 * call has the same system as the previous call, then last_i
2770		 * will be the index of the first map[] that has a matching
2771		 * system.
2772		 */
2773		for (i = last_i; i < len; i++) {
2774			if (call->class->system == map[i]->system) {
2775				/* Save the first system if need be */
2776				if (first) {
2777					last_i = i;
2778					first = false;
2779				}
2780				update_event_printk(call, map[i]);
2781				update_event_fields(call, map[i]);
2782			}
2783		}
 
2784	}
2785	up_write(&trace_event_sem);
2786}
2787
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2788static struct trace_event_file *
2789trace_create_new_event(struct trace_event_call *call,
2790		       struct trace_array *tr)
2791{
2792	struct trace_pid_list *no_pid_list;
2793	struct trace_pid_list *pid_list;
2794	struct trace_event_file *file;
2795	unsigned int first;
2796
 
 
 
2797	file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2798	if (!file)
2799		return NULL;
2800
2801	pid_list = rcu_dereference_protected(tr->filtered_pids,
2802					     lockdep_is_held(&event_mutex));
2803	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
2804					     lockdep_is_held(&event_mutex));
2805
2806	if (!trace_pid_list_first(pid_list, &first) ||
2807	    !trace_pid_list_first(no_pid_list, &first))
2808		file->flags |= EVENT_FILE_FL_PID_FILTER;
2809
2810	file->event_call = call;
2811	file->tr = tr;
2812	atomic_set(&file->sm_ref, 0);
2813	atomic_set(&file->tm_ref, 0);
2814	INIT_LIST_HEAD(&file->triggers);
2815	list_add(&file->list, &tr->events);
 
2816
2817	return file;
2818}
2819
2820#define MAX_BOOT_TRIGGERS 32
2821
2822static struct boot_triggers {
2823	const char		*event;
2824	char			*trigger;
2825} bootup_triggers[MAX_BOOT_TRIGGERS];
2826
2827static char bootup_trigger_buf[COMMAND_LINE_SIZE];
2828static int nr_boot_triggers;
2829
2830static __init int setup_trace_triggers(char *str)
2831{
2832	char *trigger;
2833	char *buf;
2834	int i;
2835
2836	strlcpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
2837	ring_buffer_expanded = true;
2838	disable_tracing_selftest("running event triggers");
2839
2840	buf = bootup_trigger_buf;
2841	for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
2842		trigger = strsep(&buf, ",");
2843		if (!trigger)
2844			break;
2845		bootup_triggers[i].event = strsep(&trigger, ".");
2846		bootup_triggers[i].trigger = strsep(&trigger, ".");
2847		if (!bootup_triggers[i].trigger)
2848			break;
2849	}
2850
2851	nr_boot_triggers = i;
2852	return 1;
2853}
2854__setup("trace_trigger=", setup_trace_triggers);
2855
2856/* Add an event to a trace directory */
2857static int
2858__trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2859{
2860	struct trace_event_file *file;
2861
2862	file = trace_create_new_event(call, tr);
 
 
 
 
 
 
2863	if (!file)
2864		return -ENOMEM;
 
 
 
2865
2866	if (eventdir_initialized)
2867		return event_create_dir(tr->event_dir, file);
2868	else
2869		return event_define_fields(call);
2870}
2871
2872static void trace_early_triggers(struct trace_event_file *file, const char *name)
2873{
2874	int ret;
2875	int i;
2876
2877	for (i = 0; i < nr_boot_triggers; i++) {
2878		if (strcmp(name, bootup_triggers[i].event))
2879			continue;
2880		mutex_lock(&event_mutex);
2881		ret = trigger_process_regex(file, bootup_triggers[i].trigger);
2882		mutex_unlock(&event_mutex);
2883		if (ret)
2884			pr_err("Failed to register trigger '%s' on event %s\n",
2885			       bootup_triggers[i].trigger,
2886			       bootup_triggers[i].event);
2887	}
2888}
2889
2890/*
2891 * Just create a descriptor for early init. A descriptor is required
2892 * for enabling events at boot. We want to enable events before
2893 * the filesystem is initialized.
2894 */
2895static int
2896__trace_early_add_new_event(struct trace_event_call *call,
2897			    struct trace_array *tr)
2898{
2899	struct trace_event_file *file;
2900	int ret;
2901
2902	file = trace_create_new_event(call, tr);
 
 
 
 
 
 
2903	if (!file)
2904		return -ENOMEM;
 
 
 
2905
2906	ret = event_define_fields(call);
2907	if (ret)
2908		return ret;
2909
2910	trace_early_triggers(file, trace_event_name(call));
2911
2912	return 0;
2913}
2914
2915struct ftrace_module_file_ops;
2916static void __add_event_to_tracers(struct trace_event_call *call);
2917
2918/* Add an additional event_call dynamically */
2919int trace_add_event_call(struct trace_event_call *call)
2920{
2921	int ret;
2922	lockdep_assert_held(&event_mutex);
2923
2924	mutex_lock(&trace_types_lock);
2925
2926	ret = __register_event(call, NULL);
2927	if (ret >= 0)
2928		__add_event_to_tracers(call);
2929
2930	mutex_unlock(&trace_types_lock);
2931	return ret;
2932}
2933EXPORT_SYMBOL_GPL(trace_add_event_call);
2934
2935/*
2936 * Must be called under locking of trace_types_lock, event_mutex and
2937 * trace_event_sem.
2938 */
2939static void __trace_remove_event_call(struct trace_event_call *call)
2940{
2941	event_remove(call);
2942	trace_destroy_fields(call);
2943	free_event_filter(call->filter);
2944	call->filter = NULL;
2945}
2946
2947static int probe_remove_event_call(struct trace_event_call *call)
2948{
2949	struct trace_array *tr;
2950	struct trace_event_file *file;
2951
2952#ifdef CONFIG_PERF_EVENTS
2953	if (call->perf_refcount)
2954		return -EBUSY;
2955#endif
2956	do_for_each_event_file(tr, file) {
2957		if (file->event_call != call)
2958			continue;
2959		/*
2960		 * We can't rely on ftrace_event_enable_disable(enable => 0)
2961		 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2962		 * TRACE_REG_UNREGISTER.
2963		 */
2964		if (file->flags & EVENT_FILE_FL_ENABLED)
2965			goto busy;
2966
2967		if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2968			tr->clear_trace = true;
2969		/*
2970		 * The do_for_each_event_file_safe() is
2971		 * a double loop. After finding the call for this
2972		 * trace_array, we use break to jump to the next
2973		 * trace_array.
2974		 */
2975		break;
2976	} while_for_each_event_file();
2977
2978	__trace_remove_event_call(call);
2979
2980	return 0;
2981 busy:
2982	/* No need to clear the trace now */
2983	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2984		tr->clear_trace = false;
2985	}
2986	return -EBUSY;
2987}
2988
2989/* Remove an event_call */
2990int trace_remove_event_call(struct trace_event_call *call)
2991{
2992	int ret;
2993
2994	lockdep_assert_held(&event_mutex);
2995
2996	mutex_lock(&trace_types_lock);
2997	down_write(&trace_event_sem);
2998	ret = probe_remove_event_call(call);
2999	up_write(&trace_event_sem);
3000	mutex_unlock(&trace_types_lock);
3001
3002	return ret;
3003}
3004EXPORT_SYMBOL_GPL(trace_remove_event_call);
3005
3006#define for_each_event(event, start, end)			\
3007	for (event = start;					\
3008	     (unsigned long)event < (unsigned long)end;		\
3009	     event++)
3010
3011#ifdef CONFIG_MODULES
3012
3013static void trace_module_add_events(struct module *mod)
3014{
3015	struct trace_event_call **call, **start, **end;
3016
3017	if (!mod->num_trace_events)
3018		return;
3019
3020	/* Don't add infrastructure for mods without tracepoints */
3021	if (trace_module_has_bad_taint(mod)) {
3022		pr_err("%s: module has bad taint, not creating trace events\n",
3023		       mod->name);
3024		return;
3025	}
3026
3027	start = mod->trace_events;
3028	end = mod->trace_events + mod->num_trace_events;
3029
3030	for_each_event(call, start, end) {
3031		__register_event(*call, mod);
3032		__add_event_to_tracers(*call);
3033	}
3034}
3035
3036static void trace_module_remove_events(struct module *mod)
3037{
3038	struct trace_event_call *call, *p;
3039	struct module_string *modstr, *m;
3040
3041	down_write(&trace_event_sem);
3042	list_for_each_entry_safe(call, p, &ftrace_events, list) {
3043		if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
3044			continue;
3045		if (call->module == mod)
3046			__trace_remove_event_call(call);
3047	}
3048	/* Check for any strings allocade for this module */
3049	list_for_each_entry_safe(modstr, m, &module_strings, next) {
3050		if (modstr->module != mod)
3051			continue;
3052		list_del(&modstr->next);
3053		kfree(modstr->str);
3054		kfree(modstr);
3055	}
3056	up_write(&trace_event_sem);
3057
3058	/*
3059	 * It is safest to reset the ring buffer if the module being unloaded
3060	 * registered any events that were used. The only worry is if
3061	 * a new module gets loaded, and takes on the same id as the events
3062	 * of this module. When printing out the buffer, traced events left
3063	 * over from this module may be passed to the new module events and
3064	 * unexpected results may occur.
3065	 */
3066	tracing_reset_all_online_cpus_unlocked();
3067}
3068
3069static int trace_module_notify(struct notifier_block *self,
3070			       unsigned long val, void *data)
3071{
3072	struct module *mod = data;
3073
3074	mutex_lock(&event_mutex);
3075	mutex_lock(&trace_types_lock);
3076	switch (val) {
3077	case MODULE_STATE_COMING:
3078		trace_module_add_events(mod);
3079		break;
3080	case MODULE_STATE_GOING:
3081		trace_module_remove_events(mod);
3082		break;
3083	}
3084	mutex_unlock(&trace_types_lock);
3085	mutex_unlock(&event_mutex);
3086
3087	return NOTIFY_OK;
3088}
3089
3090static struct notifier_block trace_module_nb = {
3091	.notifier_call = trace_module_notify,
3092	.priority = 1, /* higher than trace.c module notify */
3093};
3094#endif /* CONFIG_MODULES */
3095
3096/* Create a new event directory structure for a trace directory. */
3097static void
3098__trace_add_event_dirs(struct trace_array *tr)
3099{
3100	struct trace_event_call *call;
3101	int ret;
3102
3103	list_for_each_entry(call, &ftrace_events, list) {
3104		ret = __trace_add_new_event(call, tr);
3105		if (ret < 0)
3106			pr_warn("Could not create directory for event %s\n",
3107				trace_event_name(call));
3108	}
3109}
3110
3111/* Returns any file that matches the system and event */
3112struct trace_event_file *
3113__find_event_file(struct trace_array *tr, const char *system, const char *event)
3114{
3115	struct trace_event_file *file;
3116	struct trace_event_call *call;
3117	const char *name;
3118
3119	list_for_each_entry(file, &tr->events, list) {
3120
3121		call = file->event_call;
3122		name = trace_event_name(call);
3123
3124		if (!name || !call->class)
3125			continue;
3126
3127		if (strcmp(event, name) == 0 &&
3128		    strcmp(system, call->class->system) == 0)
3129			return file;
3130	}
3131	return NULL;
3132}
3133
3134/* Returns valid trace event files that match system and event */
3135struct trace_event_file *
3136find_event_file(struct trace_array *tr, const char *system, const char *event)
3137{
3138	struct trace_event_file *file;
3139
3140	file = __find_event_file(tr, system, event);
3141	if (!file || !file->event_call->class->reg ||
3142	    file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
3143		return NULL;
3144
3145	return file;
3146}
3147
3148/**
3149 * trace_get_event_file - Find and return a trace event file
3150 * @instance: The name of the trace instance containing the event
3151 * @system: The name of the system containing the event
3152 * @event: The name of the event
3153 *
3154 * Return a trace event file given the trace instance name, trace
3155 * system, and trace event name.  If the instance name is NULL, it
3156 * refers to the top-level trace array.
3157 *
3158 * This function will look it up and return it if found, after calling
3159 * trace_array_get() to prevent the instance from going away, and
3160 * increment the event's module refcount to prevent it from being
3161 * removed.
3162 *
3163 * To release the file, call trace_put_event_file(), which will call
3164 * trace_array_put() and decrement the event's module refcount.
3165 *
3166 * Return: The trace event on success, ERR_PTR otherwise.
3167 */
3168struct trace_event_file *trace_get_event_file(const char *instance,
3169					      const char *system,
3170					      const char *event)
3171{
3172	struct trace_array *tr = top_trace_array();
3173	struct trace_event_file *file = NULL;
3174	int ret = -EINVAL;
3175
3176	if (instance) {
3177		tr = trace_array_find_get(instance);
3178		if (!tr)
3179			return ERR_PTR(-ENOENT);
3180	} else {
3181		ret = trace_array_get(tr);
3182		if (ret)
3183			return ERR_PTR(ret);
3184	}
3185
3186	mutex_lock(&event_mutex);
3187
3188	file = find_event_file(tr, system, event);
3189	if (!file) {
3190		trace_array_put(tr);
3191		ret = -EINVAL;
3192		goto out;
3193	}
3194
3195	/* Don't let event modules unload while in use */
3196	ret = trace_event_try_get_ref(file->event_call);
3197	if (!ret) {
3198		trace_array_put(tr);
3199		ret = -EBUSY;
3200		goto out;
3201	}
3202
3203	ret = 0;
3204 out:
3205	mutex_unlock(&event_mutex);
3206
3207	if (ret)
3208		file = ERR_PTR(ret);
3209
3210	return file;
3211}
3212EXPORT_SYMBOL_GPL(trace_get_event_file);
3213
3214/**
3215 * trace_put_event_file - Release a file from trace_get_event_file()
3216 * @file: The trace event file
3217 *
3218 * If a file was retrieved using trace_get_event_file(), this should
3219 * be called when it's no longer needed.  It will cancel the previous
3220 * trace_array_get() called by that function, and decrement the
3221 * event's module refcount.
3222 */
3223void trace_put_event_file(struct trace_event_file *file)
3224{
3225	mutex_lock(&event_mutex);
3226	trace_event_put_ref(file->event_call);
3227	mutex_unlock(&event_mutex);
3228
3229	trace_array_put(file->tr);
3230}
3231EXPORT_SYMBOL_GPL(trace_put_event_file);
3232
3233#ifdef CONFIG_DYNAMIC_FTRACE
3234
3235/* Avoid typos */
3236#define ENABLE_EVENT_STR	"enable_event"
3237#define DISABLE_EVENT_STR	"disable_event"
3238
3239struct event_probe_data {
3240	struct trace_event_file	*file;
3241	unsigned long			count;
3242	int				ref;
3243	bool				enable;
3244};
3245
3246static void update_event_probe(struct event_probe_data *data)
3247{
3248	if (data->enable)
3249		clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3250	else
3251		set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
3252}
3253
3254static void
3255event_enable_probe(unsigned long ip, unsigned long parent_ip,
3256		   struct trace_array *tr, struct ftrace_probe_ops *ops,
3257		   void *data)
3258{
3259	struct ftrace_func_mapper *mapper = data;
3260	struct event_probe_data *edata;
3261	void **pdata;
3262
3263	pdata = ftrace_func_mapper_find_ip(mapper, ip);
3264	if (!pdata || !*pdata)
3265		return;
3266
3267	edata = *pdata;
3268	update_event_probe(edata);
3269}
3270
3271static void
3272event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
3273			 struct trace_array *tr, struct ftrace_probe_ops *ops,
3274			 void *data)
3275{
3276	struct ftrace_func_mapper *mapper = data;
3277	struct event_probe_data *edata;
3278	void **pdata;
3279
3280	pdata = ftrace_func_mapper_find_ip(mapper, ip);
3281	if (!pdata || !*pdata)
3282		return;
3283
3284	edata = *pdata;
3285
3286	if (!edata->count)
3287		return;
3288
3289	/* Skip if the event is in a state we want to switch to */
3290	if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
3291		return;
3292
3293	if (edata->count != -1)
3294		(edata->count)--;
3295
3296	update_event_probe(edata);
3297}
3298
3299static int
3300event_enable_print(struct seq_file *m, unsigned long ip,
3301		   struct ftrace_probe_ops *ops, void *data)
3302{
3303	struct ftrace_func_mapper *mapper = data;
3304	struct event_probe_data *edata;
3305	void **pdata;
3306
3307	pdata = ftrace_func_mapper_find_ip(mapper, ip);
3308
3309	if (WARN_ON_ONCE(!pdata || !*pdata))
3310		return 0;
3311
3312	edata = *pdata;
3313
3314	seq_printf(m, "%ps:", (void *)ip);
3315
3316	seq_printf(m, "%s:%s:%s",
3317		   edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
3318		   edata->file->event_call->class->system,
3319		   trace_event_name(edata->file->event_call));
3320
3321	if (edata->count == -1)
3322		seq_puts(m, ":unlimited\n");
3323	else
3324		seq_printf(m, ":count=%ld\n", edata->count);
3325
3326	return 0;
3327}
3328
3329static int
3330event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
3331		  unsigned long ip, void *init_data, void **data)
3332{
3333	struct ftrace_func_mapper *mapper = *data;
3334	struct event_probe_data *edata = init_data;
3335	int ret;
3336
3337	if (!mapper) {
3338		mapper = allocate_ftrace_func_mapper();
3339		if (!mapper)
3340			return -ENODEV;
3341		*data = mapper;
3342	}
3343
3344	ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
3345	if (ret < 0)
3346		return ret;
3347
3348	edata->ref++;
3349
3350	return 0;
3351}
3352
3353static int free_probe_data(void *data)
3354{
3355	struct event_probe_data *edata = data;
3356
3357	edata->ref--;
3358	if (!edata->ref) {
3359		/* Remove the SOFT_MODE flag */
3360		__ftrace_event_enable_disable(edata->file, 0, 1);
3361		trace_event_put_ref(edata->file->event_call);
3362		kfree(edata);
3363	}
3364	return 0;
3365}
3366
3367static void
3368event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
3369		  unsigned long ip, void *data)
3370{
3371	struct ftrace_func_mapper *mapper = data;
3372	struct event_probe_data *edata;
3373
3374	if (!ip) {
3375		if (!mapper)
3376			return;
3377		free_ftrace_func_mapper(mapper, free_probe_data);
3378		return;
3379	}
3380
3381	edata = ftrace_func_mapper_remove_ip(mapper, ip);
3382
3383	if (WARN_ON_ONCE(!edata))
3384		return;
3385
3386	if (WARN_ON_ONCE(edata->ref <= 0))
3387		return;
3388
3389	free_probe_data(edata);
3390}
3391
3392static struct ftrace_probe_ops event_enable_probe_ops = {
3393	.func			= event_enable_probe,
3394	.print			= event_enable_print,
3395	.init			= event_enable_init,
3396	.free			= event_enable_free,
3397};
3398
3399static struct ftrace_probe_ops event_enable_count_probe_ops = {
3400	.func			= event_enable_count_probe,
3401	.print			= event_enable_print,
3402	.init			= event_enable_init,
3403	.free			= event_enable_free,
3404};
3405
3406static struct ftrace_probe_ops event_disable_probe_ops = {
3407	.func			= event_enable_probe,
3408	.print			= event_enable_print,
3409	.init			= event_enable_init,
3410	.free			= event_enable_free,
3411};
3412
3413static struct ftrace_probe_ops event_disable_count_probe_ops = {
3414	.func			= event_enable_count_probe,
3415	.print			= event_enable_print,
3416	.init			= event_enable_init,
3417	.free			= event_enable_free,
3418};
3419
3420static int
3421event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3422		  char *glob, char *cmd, char *param, int enabled)
3423{
3424	struct trace_event_file *file;
3425	struct ftrace_probe_ops *ops;
3426	struct event_probe_data *data;
3427	const char *system;
3428	const char *event;
3429	char *number;
3430	bool enable;
3431	int ret;
3432
3433	if (!tr)
3434		return -ENODEV;
3435
3436	/* hash funcs only work with set_ftrace_filter */
3437	if (!enabled || !param)
3438		return -EINVAL;
3439
3440	system = strsep(&param, ":");
3441	if (!param)
3442		return -EINVAL;
3443
3444	event = strsep(&param, ":");
3445
3446	mutex_lock(&event_mutex);
3447
3448	ret = -EINVAL;
3449	file = find_event_file(tr, system, event);
3450	if (!file)
3451		goto out;
3452
3453	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3454
3455	if (enable)
3456		ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3457	else
3458		ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3459
3460	if (glob[0] == '!') {
3461		ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3462		goto out;
3463	}
3464
3465	ret = -ENOMEM;
3466
3467	data = kzalloc(sizeof(*data), GFP_KERNEL);
3468	if (!data)
3469		goto out;
3470
3471	data->enable = enable;
3472	data->count = -1;
3473	data->file = file;
3474
3475	if (!param)
3476		goto out_reg;
3477
3478	number = strsep(&param, ":");
3479
3480	ret = -EINVAL;
3481	if (!strlen(number))
3482		goto out_free;
3483
3484	/*
3485	 * We use the callback data field (which is a pointer)
3486	 * as our counter.
3487	 */
3488	ret = kstrtoul(number, 0, &data->count);
3489	if (ret)
3490		goto out_free;
3491
3492 out_reg:
3493	/* Don't let event modules unload while probe registered */
3494	ret = trace_event_try_get_ref(file->event_call);
3495	if (!ret) {
3496		ret = -EBUSY;
3497		goto out_free;
3498	}
3499
3500	ret = __ftrace_event_enable_disable(file, 1, 1);
3501	if (ret < 0)
3502		goto out_put;
3503
3504	ret = register_ftrace_function_probe(glob, tr, ops, data);
3505	/*
3506	 * The above returns on success the # of functions enabled,
3507	 * but if it didn't find any functions it returns zero.
3508	 * Consider no functions a failure too.
3509	 */
3510	if (!ret) {
3511		ret = -ENOENT;
3512		goto out_disable;
3513	} else if (ret < 0)
3514		goto out_disable;
3515	/* Just return zero, not the number of enabled functions */
3516	ret = 0;
3517 out:
3518	mutex_unlock(&event_mutex);
3519	return ret;
3520
3521 out_disable:
3522	__ftrace_event_enable_disable(file, 0, 1);
3523 out_put:
3524	trace_event_put_ref(file->event_call);
3525 out_free:
3526	kfree(data);
3527	goto out;
3528}
3529
3530static struct ftrace_func_command event_enable_cmd = {
3531	.name			= ENABLE_EVENT_STR,
3532	.func			= event_enable_func,
3533};
3534
3535static struct ftrace_func_command event_disable_cmd = {
3536	.name			= DISABLE_EVENT_STR,
3537	.func			= event_enable_func,
3538};
3539
3540static __init int register_event_cmds(void)
3541{
3542	int ret;
3543
3544	ret = register_ftrace_command(&event_enable_cmd);
3545	if (WARN_ON(ret < 0))
3546		return ret;
3547	ret = register_ftrace_command(&event_disable_cmd);
3548	if (WARN_ON(ret < 0))
3549		unregister_ftrace_command(&event_enable_cmd);
3550	return ret;
3551}
3552#else
3553static inline int register_event_cmds(void) { return 0; }
3554#endif /* CONFIG_DYNAMIC_FTRACE */
3555
3556/*
3557 * The top level array and trace arrays created by boot-time tracing
3558 * have already had its trace_event_file descriptors created in order
3559 * to allow for early events to be recorded.
3560 * This function is called after the tracefs has been initialized,
3561 * and we now have to create the files associated to the events.
3562 */
3563static void __trace_early_add_event_dirs(struct trace_array *tr)
3564{
3565	struct trace_event_file *file;
3566	int ret;
3567
3568
3569	list_for_each_entry(file, &tr->events, list) {
3570		ret = event_create_dir(tr->event_dir, file);
3571		if (ret < 0)
3572			pr_warn("Could not create directory for event %s\n",
3573				trace_event_name(file->event_call));
3574	}
3575}
3576
3577/*
3578 * For early boot up, the top trace array and the trace arrays created
3579 * by boot-time tracing require to have a list of events that can be
3580 * enabled. This must be done before the filesystem is set up in order
3581 * to allow events to be traced early.
3582 */
3583void __trace_early_add_events(struct trace_array *tr)
3584{
3585	struct trace_event_call *call;
3586	int ret;
3587
3588	list_for_each_entry(call, &ftrace_events, list) {
3589		/* Early boot up should not have any modules loaded */
3590		if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
3591		    WARN_ON_ONCE(call->module))
3592			continue;
3593
3594		ret = __trace_early_add_new_event(call, tr);
3595		if (ret < 0)
3596			pr_warn("Could not create early event %s\n",
3597				trace_event_name(call));
3598	}
3599}
3600
3601/* Remove the event directory structure for a trace directory. */
3602static void
3603__trace_remove_event_dirs(struct trace_array *tr)
3604{
3605	struct trace_event_file *file, *next;
3606
3607	list_for_each_entry_safe(file, next, &tr->events, list)
3608		remove_event_file_dir(file);
3609}
3610
3611static void __add_event_to_tracers(struct trace_event_call *call)
3612{
3613	struct trace_array *tr;
3614
3615	list_for_each_entry(tr, &ftrace_trace_arrays, list)
3616		__trace_add_new_event(call, tr);
3617}
3618
3619extern struct trace_event_call *__start_ftrace_events[];
3620extern struct trace_event_call *__stop_ftrace_events[];
3621
3622static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3623
3624static __init int setup_trace_event(char *str)
3625{
3626	strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3627	ring_buffer_expanded = true;
3628	disable_tracing_selftest("running event tracing");
3629
3630	return 1;
3631}
3632__setup("trace_event=", setup_trace_event);
3633
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3634/* Expects to have event_mutex held when called */
3635static int
3636create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3637{
3638	struct dentry *d_events;
3639	struct dentry *entry;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3640
3641	entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent,
3642				  tr, &ftrace_set_event_fops);
3643	if (!entry)
3644		return -ENOMEM;
3645
3646	d_events = tracefs_create_dir("events", parent);
3647	if (!d_events) {
 
 
 
3648		pr_warn("Could not create tracefs 'events' directory\n");
3649		return -ENOMEM;
3650	}
3651
3652	entry = trace_create_file("enable", TRACE_MODE_WRITE, d_events,
3653				  tr, &ftrace_tr_enable_fops);
3654	if (!entry)
3655		return -ENOMEM;
3656
3657	/* There are not as crucial, just warn if they are not created */
3658
3659	trace_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
3660			  tr, &ftrace_set_event_pid_fops);
3661
3662	trace_create_file("set_event_notrace_pid",
3663			  TRACE_MODE_WRITE, parent, tr,
3664			  &ftrace_set_event_notrace_pid_fops);
3665
3666	/* ring buffer internal formats */
3667	trace_create_file("header_page", TRACE_MODE_READ, d_events,
3668				  ring_buffer_print_page_header,
3669				  &ftrace_show_header_fops);
3670
3671	trace_create_file("header_event", TRACE_MODE_READ, d_events,
3672				  ring_buffer_print_entry_header,
3673				  &ftrace_show_header_fops);
3674
3675	tr->event_dir = d_events;
3676
3677	return 0;
3678}
3679
3680/**
3681 * event_trace_add_tracer - add a instance of a trace_array to events
3682 * @parent: The parent dentry to place the files/directories for events in
3683 * @tr: The trace array associated with these events
3684 *
3685 * When a new instance is created, it needs to set up its events
3686 * directory, as well as other files associated with events. It also
3687 * creates the event hierarchy in the @parent/events directory.
3688 *
3689 * Returns 0 on success.
3690 *
3691 * Must be called with event_mutex held.
3692 */
3693int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3694{
3695	int ret;
3696
3697	lockdep_assert_held(&event_mutex);
3698
3699	ret = create_event_toplevel_files(parent, tr);
3700	if (ret)
3701		goto out;
3702
3703	down_write(&trace_event_sem);
3704	/* If tr already has the event list, it is initialized in early boot. */
3705	if (unlikely(!list_empty(&tr->events)))
3706		__trace_early_add_event_dirs(tr);
3707	else
3708		__trace_add_event_dirs(tr);
3709	up_write(&trace_event_sem);
3710
3711 out:
3712	return ret;
3713}
3714
3715/*
3716 * The top trace array already had its file descriptors created.
3717 * Now the files themselves need to be created.
3718 */
3719static __init int
3720early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3721{
3722	int ret;
3723
3724	mutex_lock(&event_mutex);
3725
3726	ret = create_event_toplevel_files(parent, tr);
3727	if (ret)
3728		goto out_unlock;
3729
3730	down_write(&trace_event_sem);
3731	__trace_early_add_event_dirs(tr);
3732	up_write(&trace_event_sem);
3733
3734 out_unlock:
3735	mutex_unlock(&event_mutex);
3736
3737	return ret;
3738}
3739
3740/* Must be called with event_mutex held */
3741int event_trace_del_tracer(struct trace_array *tr)
3742{
3743	lockdep_assert_held(&event_mutex);
3744
3745	/* Disable any event triggers and associated soft-disabled events */
3746	clear_event_triggers(tr);
3747
3748	/* Clear the pid list */
3749	__ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3750
3751	/* Disable any running events */
3752	__ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3753
3754	/* Make sure no more events are being executed */
3755	tracepoint_synchronize_unregister();
3756
3757	down_write(&trace_event_sem);
3758	__trace_remove_event_dirs(tr);
3759	tracefs_remove(tr->event_dir);
3760	up_write(&trace_event_sem);
3761
3762	tr->event_dir = NULL;
3763
3764	return 0;
3765}
3766
3767static __init int event_trace_memsetup(void)
3768{
3769	field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3770	file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3771	return 0;
3772}
3773
3774static __init void
3775early_enable_events(struct trace_array *tr, bool disable_first)
3776{
3777	char *buf = bootup_event_buf;
3778	char *token;
3779	int ret;
3780
3781	while (true) {
3782		token = strsep(&buf, ",");
3783
3784		if (!token)
3785			break;
3786
3787		if (*token) {
3788			/* Restarting syscalls requires that we stop them first */
3789			if (disable_first)
3790				ftrace_set_clr_event(tr, token, 0);
3791
3792			ret = ftrace_set_clr_event(tr, token, 1);
3793			if (ret)
3794				pr_warn("Failed to enable trace event: %s\n", token);
3795		}
3796
3797		/* Put back the comma to allow this to be called again */
3798		if (buf)
3799			*(buf - 1) = ',';
3800	}
3801}
3802
3803static __init int event_trace_enable(void)
3804{
3805	struct trace_array *tr = top_trace_array();
3806	struct trace_event_call **iter, *call;
3807	int ret;
3808
3809	if (!tr)
3810		return -ENODEV;
3811
3812	for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3813
3814		call = *iter;
3815		ret = event_init(call);
3816		if (!ret)
3817			list_add(&call->list, &ftrace_events);
3818	}
3819
3820	register_trigger_cmds();
3821
3822	/*
3823	 * We need the top trace array to have a working set of trace
3824	 * points at early init, before the debug files and directories
3825	 * are created. Create the file entries now, and attach them
3826	 * to the actual file dentries later.
3827	 */
3828	__trace_early_add_events(tr);
3829
3830	early_enable_events(tr, false);
3831
3832	trace_printk_start_comm();
3833
3834	register_event_cmds();
3835
3836
3837	return 0;
3838}
3839
3840/*
3841 * event_trace_enable() is called from trace_event_init() first to
3842 * initialize events and perhaps start any events that are on the
3843 * command line. Unfortunately, there are some events that will not
3844 * start this early, like the system call tracepoints that need
3845 * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
3846 * event_trace_enable() is called before pid 1 starts, and this flag
3847 * is never set, making the syscall tracepoint never get reached, but
3848 * the event is enabled regardless (and not doing anything).
3849 */
3850static __init int event_trace_enable_again(void)
3851{
3852	struct trace_array *tr;
3853
3854	tr = top_trace_array();
3855	if (!tr)
3856		return -ENODEV;
3857
3858	early_enable_events(tr, true);
3859
3860	return 0;
3861}
3862
3863early_initcall(event_trace_enable_again);
3864
3865/* Init fields which doesn't related to the tracefs */
3866static __init int event_trace_init_fields(void)
3867{
3868	if (trace_define_generic_fields())
3869		pr_warn("tracing: Failed to allocated generic fields");
3870
3871	if (trace_define_common_fields())
3872		pr_warn("tracing: Failed to allocate common fields");
3873
3874	return 0;
3875}
3876
3877__init int event_trace_init(void)
3878{
3879	struct trace_array *tr;
3880	int ret;
3881
3882	tr = top_trace_array();
3883	if (!tr)
3884		return -ENODEV;
3885
3886	trace_create_file("available_events", TRACE_MODE_READ,
3887			  NULL, tr, &ftrace_avail_fops);
3888
3889	ret = early_event_add_tracer(NULL, tr);
3890	if (ret)
3891		return ret;
3892
3893#ifdef CONFIG_MODULES
3894	ret = register_module_notifier(&trace_module_nb);
3895	if (ret)
3896		pr_warn("Failed to register trace events module notifier\n");
3897#endif
3898
3899	eventdir_initialized = true;
3900
3901	return 0;
3902}
3903
3904void __init trace_event_init(void)
3905{
3906	event_trace_memsetup();
3907	init_ftrace_syscalls();
3908	event_trace_enable();
3909	event_trace_init_fields();
3910}
3911
3912#ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
3913
3914static DEFINE_SPINLOCK(test_spinlock);
3915static DEFINE_SPINLOCK(test_spinlock_irq);
3916static DEFINE_MUTEX(test_mutex);
3917
3918static __init void test_work(struct work_struct *dummy)
3919{
3920	spin_lock(&test_spinlock);
3921	spin_lock_irq(&test_spinlock_irq);
3922	udelay(1);
3923	spin_unlock_irq(&test_spinlock_irq);
3924	spin_unlock(&test_spinlock);
3925
3926	mutex_lock(&test_mutex);
3927	msleep(1);
3928	mutex_unlock(&test_mutex);
3929}
3930
3931static __init int event_test_thread(void *unused)
3932{
3933	void *test_malloc;
3934
3935	test_malloc = kmalloc(1234, GFP_KERNEL);
3936	if (!test_malloc)
3937		pr_info("failed to kmalloc\n");
3938
3939	schedule_on_each_cpu(test_work);
3940
3941	kfree(test_malloc);
3942
3943	set_current_state(TASK_INTERRUPTIBLE);
3944	while (!kthread_should_stop()) {
3945		schedule();
3946		set_current_state(TASK_INTERRUPTIBLE);
3947	}
3948	__set_current_state(TASK_RUNNING);
3949
3950	return 0;
3951}
3952
3953/*
3954 * Do various things that may trigger events.
3955 */
3956static __init void event_test_stuff(void)
3957{
3958	struct task_struct *test_thread;
3959
3960	test_thread = kthread_run(event_test_thread, NULL, "test-events");
3961	msleep(1);
3962	kthread_stop(test_thread);
3963}
3964
3965/*
3966 * For every trace event defined, we will test each trace point separately,
3967 * and then by groups, and finally all trace points.
3968 */
3969static __init void event_trace_self_tests(void)
3970{
3971	struct trace_subsystem_dir *dir;
3972	struct trace_event_file *file;
3973	struct trace_event_call *call;
3974	struct event_subsystem *system;
3975	struct trace_array *tr;
3976	int ret;
3977
3978	tr = top_trace_array();
3979	if (!tr)
3980		return;
3981
3982	pr_info("Running tests on trace events:\n");
3983
3984	list_for_each_entry(file, &tr->events, list) {
3985
3986		call = file->event_call;
3987
3988		/* Only test those that have a probe */
3989		if (!call->class || !call->class->probe)
3990			continue;
3991
3992/*
3993 * Testing syscall events here is pretty useless, but
3994 * we still do it if configured. But this is time consuming.
3995 * What we really need is a user thread to perform the
3996 * syscalls as we test.
3997 */
3998#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3999		if (call->class->system &&
4000		    strcmp(call->class->system, "syscalls") == 0)
4001			continue;
4002#endif
4003
4004		pr_info("Testing event %s: ", trace_event_name(call));
4005
4006		/*
4007		 * If an event is already enabled, someone is using
4008		 * it and the self test should not be on.
4009		 */
4010		if (file->flags & EVENT_FILE_FL_ENABLED) {
4011			pr_warn("Enabled event during self test!\n");
4012			WARN_ON_ONCE(1);
4013			continue;
4014		}
4015
4016		ftrace_event_enable_disable(file, 1);
4017		event_test_stuff();
4018		ftrace_event_enable_disable(file, 0);
4019
4020		pr_cont("OK\n");
4021	}
4022
4023	/* Now test at the sub system level */
4024
4025	pr_info("Running tests on trace event systems:\n");
4026
4027	list_for_each_entry(dir, &tr->systems, list) {
4028
4029		system = dir->subsystem;
4030
4031		/* the ftrace system is special, skip it */
4032		if (strcmp(system->name, "ftrace") == 0)
4033			continue;
4034
4035		pr_info("Testing event system %s: ", system->name);
4036
4037		ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
4038		if (WARN_ON_ONCE(ret)) {
4039			pr_warn("error enabling system %s\n",
4040				system->name);
4041			continue;
4042		}
4043
4044		event_test_stuff();
4045
4046		ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
4047		if (WARN_ON_ONCE(ret)) {
4048			pr_warn("error disabling system %s\n",
4049				system->name);
4050			continue;
4051		}
4052
4053		pr_cont("OK\n");
4054	}
4055
4056	/* Test with all events enabled */
4057
4058	pr_info("Running tests on all trace events:\n");
4059	pr_info("Testing all events: ");
4060
4061	ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
4062	if (WARN_ON_ONCE(ret)) {
4063		pr_warn("error enabling all events\n");
4064		return;
4065	}
4066
4067	event_test_stuff();
4068
4069	/* reset sysname */
4070	ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
4071	if (WARN_ON_ONCE(ret)) {
4072		pr_warn("error disabling all events\n");
4073		return;
4074	}
4075
4076	pr_cont("OK\n");
4077}
4078
4079#ifdef CONFIG_FUNCTION_TRACER
4080
4081static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
4082
4083static struct trace_event_file event_trace_file __initdata;
4084
4085static void __init
4086function_test_events_call(unsigned long ip, unsigned long parent_ip,
4087			  struct ftrace_ops *op, struct ftrace_regs *regs)
4088{
4089	struct trace_buffer *buffer;
4090	struct ring_buffer_event *event;
4091	struct ftrace_entry *entry;
4092	unsigned int trace_ctx;
4093	long disabled;
4094	int cpu;
4095
4096	trace_ctx = tracing_gen_ctx();
4097	preempt_disable_notrace();
4098	cpu = raw_smp_processor_id();
4099	disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
4100
4101	if (disabled != 1)
4102		goto out;
4103
4104	event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
4105						TRACE_FN, sizeof(*entry),
4106						trace_ctx);
4107	if (!event)
4108		goto out;
4109	entry	= ring_buffer_event_data(event);
4110	entry->ip			= ip;
4111	entry->parent_ip		= parent_ip;
4112
4113	event_trigger_unlock_commit(&event_trace_file, buffer, event,
4114				    entry, trace_ctx);
4115 out:
4116	atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
4117	preempt_enable_notrace();
4118}
4119
4120static struct ftrace_ops trace_ops __initdata  =
4121{
4122	.func = function_test_events_call,
4123};
4124
4125static __init void event_trace_self_test_with_function(void)
4126{
4127	int ret;
4128
4129	event_trace_file.tr = top_trace_array();
4130	if (WARN_ON(!event_trace_file.tr))
4131		return;
4132
4133	ret = register_ftrace_function(&trace_ops);
4134	if (WARN_ON(ret < 0)) {
4135		pr_info("Failed to enable function tracer for event tests\n");
4136		return;
4137	}
4138	pr_info("Running tests again, along with the function tracer\n");
4139	event_trace_self_tests();
4140	unregister_ftrace_function(&trace_ops);
4141}
4142#else
4143static __init void event_trace_self_test_with_function(void)
4144{
4145}
4146#endif
4147
4148static __init int event_trace_self_tests_init(void)
4149{
4150	if (!tracing_selftest_disabled) {
4151		event_trace_self_tests();
4152		event_trace_self_test_with_function();
4153	}
4154
4155	return 0;
4156}
4157
4158late_initcall(event_trace_self_tests_init);
4159
4160#endif