1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * ring buffer based function tracer
   4 *
   5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
   6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
   7 *
   8 * Originally taken from the RT patch by:
   9 *    Arnaldo Carvalho de Melo <acme@redhat.com>
  10 *
  11 * Based on code from the latency_tracer, that is:
  12 *  Copyright (C) 2004-2006 Ingo Molnar
  13 *  Copyright (C) 2004 Nadia Yvette Chambers
  14 */
  15#include <linux/ring_buffer.h>
  16#include <generated/utsrelease.h>
  17#include <linux/stacktrace.h>
  18#include <linux/writeback.h>
  19#include <linux/kallsyms.h>
  20#include <linux/security.h>
  21#include <linux/seq_file.h>
  22#include <linux/notifier.h>
  23#include <linux/irqflags.h>
  24#include <linux/debugfs.h>
  25#include <linux/tracefs.h>
  26#include <linux/pagemap.h>
  27#include <linux/hardirq.h>
  28#include <linux/linkage.h>
  29#include <linux/uaccess.h>
  30#include <linux/vmalloc.h>
  31#include <linux/ftrace.h>
  32#include <linux/module.h>
  33#include <linux/percpu.h>
  34#include <linux/splice.h>
  35#include <linux/kdebug.h>
  36#include <linux/string.h>
  37#include <linux/mount.h>
  38#include <linux/rwsem.h>
  39#include <linux/slab.h>
  40#include <linux/ctype.h>
  41#include <linux/init.h>
 
  42#include <linux/poll.h>
  43#include <linux/nmi.h>
  44#include <linux/fs.h>
  45#include <linux/trace.h>
  46#include <linux/sched/clock.h>
  47#include <linux/sched/rt.h>
 
 
 
  48
  49#include "trace.h"
  50#include "trace_output.h"
  51
  52/*
  53 * On boot up, the ring buffer is set to the minimum size, so that
  54 * we do not waste memory on systems that are not using tracing.
  55 */
  56bool ring_buffer_expanded;
  57
  58/*
  59 * We need to change this state when a selftest is running.
  60 * A selftest will lurk into the ring-buffer to count the
  61 * entries inserted during the selftest although some concurrent
  62 * insertions into the ring-buffer such as trace_printk could occurred
  63 * at the same time, giving false positive or negative results.
  64 */
  65static bool __read_mostly tracing_selftest_running;
  66
  67/*
  68 * If a tracer is running, we do not want to run SELFTEST.
 
  69 */
  70bool __read_mostly tracing_selftest_disabled;
  71
 
 
 
 
 
 
 
 
 
 
  72/* Pipe tracepoints to printk */
  73struct trace_iterator *tracepoint_print_iter;
  74int tracepoint_printk;
 
  75static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
  76
  77/* For tracers that don't implement custom flags */
  78static struct tracer_opt dummy_tracer_opt[] = {
  79	{ }
  80};
  81
  82static int
  83dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
  84{
  85	return 0;
  86}
  87
  88/*
  89 * To prevent the comm cache from being overwritten when no
  90 * tracing is active, only save the comm when a trace event
  91 * occurred.
  92 */
  93static DEFINE_PER_CPU(bool, trace_taskinfo_save);
  94
  95/*
  96 * Kill all tracing for good (never come back).
  97 * It is initialized to 1 but will turn to zero if the initialization
  98 * of the tracer is successful. But that is the only place that sets
  99 * this back to zero.
 100 */
 101static int tracing_disabled = 1;
 102
 103cpumask_var_t __read_mostly	tracing_buffer_mask;
 104
 105/*
 106 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
 107 *
 108 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
 109 * is set, then ftrace_dump is called. This will output the contents
 110 * of the ftrace buffers to the console.  This is very useful for
 111 * capturing traces that lead to crashes and outputing it to a
 112 * serial console.
 113 *
 114 * It is default off, but you can enable it with either specifying
 115 * "ftrace_dump_on_oops" in the kernel command line, or setting
 116 * /proc/sys/kernel/ftrace_dump_on_oops
 117 * Set 1 if you want to dump buffers of all CPUs
 118 * Set 2 if you want to dump the buffer of the CPU that triggered oops
 119 */
 120
 121enum ftrace_dump_mode ftrace_dump_on_oops;
 122
 123/* When set, tracing will stop when a WARN*() is hit */
 124int __disable_trace_on_warning;
 125
 126#ifdef CONFIG_TRACE_EVAL_MAP_FILE
 127/* Map of enums to their values, for "eval_map" file */
 128struct trace_eval_map_head {
 129	struct module			*mod;
 130	unsigned long			length;
 131};
 132
 133union trace_eval_map_item;
 134
 135struct trace_eval_map_tail {
 136	/*
 137	 * "end" is first and points to NULL as it must be different
 138	 * than "mod" or "eval_string"
 139	 */
 140	union trace_eval_map_item	*next;
 141	const char			*end;	/* points to NULL */
 142};
 143
 144static DEFINE_MUTEX(trace_eval_mutex);
 145
 146/*
 147 * The trace_eval_maps are saved in an array with two extra elements,
 148 * one at the beginning, and one at the end. The beginning item contains
 149 * the count of the saved maps (head.length), and the module they
 150 * belong to if not built in (head.mod). The ending item contains a
 151 * pointer to the next array of saved eval_map items.
 152 */
 153union trace_eval_map_item {
 154	struct trace_eval_map		map;
 155	struct trace_eval_map_head	head;
 156	struct trace_eval_map_tail	tail;
 157};
 158
 159static union trace_eval_map_item *trace_eval_maps;
 160#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
 161
 162static int tracing_set_tracer(struct trace_array *tr, const char *buf);
 163static void ftrace_trace_userstack(struct ring_buffer *buffer,
 164				   unsigned long flags, int pc);
 
 165
 166#define MAX_TRACER_SIZE		100
 167static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
 168static char *default_bootup_tracer;
 169
 170static bool allocate_snapshot;
 171
 172static int __init set_cmdline_ftrace(char *str)
 173{
 174	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 175	default_bootup_tracer = bootup_tracer_buf;
 176	/* We are using ftrace early, expand it */
 177	ring_buffer_expanded = true;
 178	return 1;
 179}
 180__setup("ftrace=", set_cmdline_ftrace);
 181
 182static int __init set_ftrace_dump_on_oops(char *str)
 183{
 184	if (*str++ != '=' || !*str) {
 185		ftrace_dump_on_oops = DUMP_ALL;
 186		return 1;
 187	}
 188
 189	if (!strcmp("orig_cpu", str)) {
 190		ftrace_dump_on_oops = DUMP_ORIG;
 191                return 1;
 192        }
 193
 194        return 0;
 195}
 196__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
 197
 198static int __init stop_trace_on_warning(char *str)
 199{
 200	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
 201		__disable_trace_on_warning = 1;
 202	return 1;
 203}
 204__setup("traceoff_on_warning", stop_trace_on_warning);
 205
 206static int __init boot_alloc_snapshot(char *str)
 207{
 208	allocate_snapshot = true;
 209	/* We also need the main ring buffer expanded */
 210	ring_buffer_expanded = true;
 211	return 1;
 212}
 213__setup("alloc_snapshot", boot_alloc_snapshot);
 214
 215
 216static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
 217
 218static int __init set_trace_boot_options(char *str)
 219{
 220	strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
 221	return 0;
 222}
 223__setup("trace_options=", set_trace_boot_options);
 224
 225static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
 226static char *trace_boot_clock __initdata;
 227
 228static int __init set_trace_boot_clock(char *str)
 229{
 230	strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
 231	trace_boot_clock = trace_boot_clock_buf;
 232	return 0;
 233}
 234__setup("trace_clock=", set_trace_boot_clock);
 235
 236static int __init set_tracepoint_printk(char *str)
 237{
 238	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
 239		tracepoint_printk = 1;
 240	return 1;
 241}
 242__setup("tp_printk", set_tracepoint_printk);
 243
 
 
 
 
 
 
 
 244unsigned long long ns2usecs(u64 nsec)
 245{
 246	nsec += 500;
 247	do_div(nsec, 1000);
 248	return nsec;
 249}
 250
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 251/* trace_flags holds trace_options default values */
 252#define TRACE_DEFAULT_FLAGS						\
 253	(FUNCTION_DEFAULT_FLAGS |					\
 254	 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |			\
 255	 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO |		\
 256	 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |			\
 257	 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
 
 258
 259/* trace_options that are only supported by global_trace */
 260#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK |			\
 261	       TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
 262
 263/* trace_flags that are default zero for instances */
 264#define ZEROED_TRACE_FLAGS \
 265	(TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
 266
 267/*
 268 * The global_trace is the descriptor that holds the top-level tracing
 269 * buffers for the live tracing.
 270 */
 271static struct trace_array global_trace = {
 272	.trace_flags = TRACE_DEFAULT_FLAGS,
 273};
 274
 275LIST_HEAD(ftrace_trace_arrays);
 276
 277int trace_array_get(struct trace_array *this_tr)
 278{
 279	struct trace_array *tr;
 280	int ret = -ENODEV;
 281
 282	mutex_lock(&trace_types_lock);
 283	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
 284		if (tr == this_tr) {
 285			tr->ref++;
 286			ret = 0;
 287			break;
 288		}
 289	}
 290	mutex_unlock(&trace_types_lock);
 291
 292	return ret;
 293}
 294
 295static void __trace_array_put(struct trace_array *this_tr)
 296{
 297	WARN_ON(!this_tr->ref);
 298	this_tr->ref--;
 299}
 300
 
 
 
 
 
 
 
 
 
 301void trace_array_put(struct trace_array *this_tr)
 302{
 
 
 
 303	mutex_lock(&trace_types_lock);
 304	__trace_array_put(this_tr);
 305	mutex_unlock(&trace_types_lock);
 306}
 
 307
 308int tracing_check_open_get_tr(struct trace_array *tr)
 309{
 310	int ret;
 311
 312	ret = security_locked_down(LOCKDOWN_TRACEFS);
 313	if (ret)
 314		return ret;
 315
 316	if (tracing_disabled)
 317		return -ENODEV;
 318
 319	if (tr && trace_array_get(tr) < 0)
 320		return -ENODEV;
 321
 322	return 0;
 323}
 324
 325int call_filter_check_discard(struct trace_event_call *call, void *rec,
 326			      struct ring_buffer *buffer,
 327			      struct ring_buffer_event *event)
 328{
 329	if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
 330	    !filter_match_preds(call->filter, rec)) {
 331		__trace_event_discard_commit(buffer, event);
 332		return 1;
 333	}
 334
 335	return 0;
 336}
 337
 338void trace_free_pid_list(struct trace_pid_list *pid_list)
 339{
 340	vfree(pid_list->pids);
 341	kfree(pid_list);
 342}
 343
 344/**
 345 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
 346 * @filtered_pids: The list of pids to check
 347 * @search_pid: The PID to find in @filtered_pids
 348 *
 349 * Returns true if @search_pid is fonud in @filtered_pids, and false otherwis.
 350 */
 351bool
 352trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
 353{
 354	/*
 355	 * If pid_max changed after filtered_pids was created, we
 356	 * by default ignore all pids greater than the previous pid_max.
 357	 */
 358	if (search_pid >= filtered_pids->pid_max)
 359		return false;
 360
 361	return test_bit(search_pid, filtered_pids->pids);
 362}
 363
 364/**
 365 * trace_ignore_this_task - should a task be ignored for tracing
 366 * @filtered_pids: The list of pids to check
 
 367 * @task: The task that should be ignored if not filtered
 368 *
 369 * Checks if @task should be traced or not from @filtered_pids.
 370 * Returns true if @task should *NOT* be traced.
 371 * Returns false if @task should be traced.
 372 */
 373bool
 374trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
 375{
 376	/*
 377	 * Return false, because if filtered_pids does not exist,
 378	 * all pids are good to trace.
 379	 */
 380	if (!filtered_pids)
 381		return false;
 382
 383	return !trace_find_filtered_pid(filtered_pids, task->pid);
 
 
 
 
 
 
 384}
 385
 386/**
 387 * trace_filter_add_remove_task - Add or remove a task from a pid_list
 388 * @pid_list: The list to modify
 389 * @self: The current task for fork or NULL for exit
 390 * @task: The task to add or remove
 391 *
 392 * If adding a task, if @self is defined, the task is only added if @self
 393 * is also included in @pid_list. This happens on fork and tasks should
 394 * only be added when the parent is listed. If @self is NULL, then the
 395 * @task pid will be removed from the list, which would happen on exit
 396 * of a task.
 397 */
 398void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
 399				  struct task_struct *self,
 400				  struct task_struct *task)
 401{
 402	if (!pid_list)
 403		return;
 404
 405	/* For forks, we only add if the forking task is listed */
 406	if (self) {
 407		if (!trace_find_filtered_pid(pid_list, self->pid))
 408			return;
 409	}
 410
 411	/* Sorry, but we don't support pid_max changing after setting */
 412	if (task->pid >= pid_list->pid_max)
 413		return;
 414
 415	/* "self" is set for forks, and NULL for exits */
 416	if (self)
 417		set_bit(task->pid, pid_list->pids);
 418	else
 419		clear_bit(task->pid, pid_list->pids);
 420}
 421
 422/**
 423 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
 424 * @pid_list: The pid list to show
 425 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
 426 * @pos: The position of the file
 427 *
 428 * This is used by the seq_file "next" operation to iterate the pids
 429 * listed in a trace_pid_list structure.
 430 *
 431 * Returns the pid+1 as we want to display pid of zero, but NULL would
 432 * stop the iteration.
 433 */
 434void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
 435{
 436	unsigned long pid = (unsigned long)v;
 437
 438	(*pos)++;
 439
 440	/* pid already is +1 of the actual prevous bit */
 441	pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
 442
 443	/* Return pid + 1 to allow zero to be represented */
 444	if (pid < pid_list->pid_max)
 445		return (void *)(pid + 1);
 446
 447	return NULL;
 448}
 449
 450/**
 451 * trace_pid_start - Used for seq_file to start reading pid lists
 452 * @pid_list: The pid list to show
 453 * @pos: The position of the file
 454 *
 455 * This is used by seq_file "start" operation to start the iteration
 456 * of listing pids.
 457 *
 458 * Returns the pid+1 as we want to display pid of zero, but NULL would
 459 * stop the iteration.
 460 */
 461void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
 462{
 463	unsigned long pid;
 464	loff_t l = 0;
 465
 466	pid = find_first_bit(pid_list->pids, pid_list->pid_max);
 467	if (pid >= pid_list->pid_max)
 468		return NULL;
 469
 470	/* Return pid + 1 so that zero can be the exit value */
 471	for (pid++; pid && l < *pos;
 472	     pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
 473		;
 474	return (void *)pid;
 475}
 476
 477/**
 478 * trace_pid_show - show the current pid in seq_file processing
 479 * @m: The seq_file structure to write into
 480 * @v: A void pointer of the pid (+1) value to display
 481 *
 482 * Can be directly used by seq_file operations to display the current
 483 * pid value.
 484 */
 485int trace_pid_show(struct seq_file *m, void *v)
 486{
 487	unsigned long pid = (unsigned long)v - 1;
 488
 489	seq_printf(m, "%lu\n", pid);
 490	return 0;
 491}
 492
 493/* 128 should be much more than enough */
 494#define PID_BUF_SIZE		127
 495
 496int trace_pid_write(struct trace_pid_list *filtered_pids,
 497		    struct trace_pid_list **new_pid_list,
 498		    const char __user *ubuf, size_t cnt)
 499{
 500	struct trace_pid_list *pid_list;
 501	struct trace_parser parser;
 502	unsigned long val;
 503	int nr_pids = 0;
 504	ssize_t read = 0;
 505	ssize_t ret = 0;
 506	loff_t pos;
 507	pid_t pid;
 508
 509	if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
 510		return -ENOMEM;
 511
 512	/*
 513	 * Always recreate a new array. The write is an all or nothing
 514	 * operation. Always create a new array when adding new pids by
 515	 * the user. If the operation fails, then the current list is
 516	 * not modified.
 517	 */
 518	pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
 519	if (!pid_list) {
 520		trace_parser_put(&parser);
 521		return -ENOMEM;
 522	}
 523
 524	pid_list->pid_max = READ_ONCE(pid_max);
 525
 526	/* Only truncating will shrink pid_max */
 527	if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
 528		pid_list->pid_max = filtered_pids->pid_max;
 529
 530	pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
 531	if (!pid_list->pids) {
 532		trace_parser_put(&parser);
 533		kfree(pid_list);
 534		return -ENOMEM;
 535	}
 536
 537	if (filtered_pids) {
 538		/* copy the current bits to the new max */
 539		for_each_set_bit(pid, filtered_pids->pids,
 540				 filtered_pids->pid_max) {
 541			set_bit(pid, pid_list->pids);
 542			nr_pids++;
 543		}
 544	}
 545
 546	while (cnt > 0) {
 547
 548		pos = 0;
 549
 550		ret = trace_get_user(&parser, ubuf, cnt, &pos);
 551		if (ret < 0 || !trace_parser_loaded(&parser))
 552			break;
 553
 554		read += ret;
 555		ubuf += ret;
 556		cnt -= ret;
 557
 558		ret = -EINVAL;
 559		if (kstrtoul(parser.buffer, 0, &val))
 560			break;
 561		if (val >= pid_list->pid_max)
 562			break;
 563
 564		pid = (pid_t)val;
 565
 566		set_bit(pid, pid_list->pids);
 567		nr_pids++;
 568
 569		trace_parser_clear(&parser);
 570		ret = 0;
 571	}
 572	trace_parser_put(&parser);
 573
 574	if (ret < 0) {
 575		trace_free_pid_list(pid_list);
 576		return ret;
 577	}
 578
 579	if (!nr_pids) {
 580		/* Cleared the list of pids */
 581		trace_free_pid_list(pid_list);
 582		read = ret;
 583		pid_list = NULL;
 584	}
 585
 586	*new_pid_list = pid_list;
 587
 588	return read;
 589}
 590
 591static u64 buffer_ftrace_now(struct trace_buffer *buf, int cpu)
 592{
 593	u64 ts;
 594
 595	/* Early boot up does not have a buffer yet */
 596	if (!buf->buffer)
 597		return trace_clock_local();
 598
 599	ts = ring_buffer_time_stamp(buf->buffer, cpu);
 600	ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
 601
 602	return ts;
 603}
 604
 605u64 ftrace_now(int cpu)
 606{
 607	return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
 608}
 609
 610/**
 611 * tracing_is_enabled - Show if global_trace has been disabled
 612 *
 613 * Shows if the global trace has been enabled or not. It uses the
 614 * mirror flag "buffer_disabled" to be used in fast paths such as for
 615 * the irqsoff tracer. But it may be inaccurate due to races. If you
 616 * need to know the accurate state, use tracing_is_on() which is a little
 617 * slower, but accurate.
 618 */
 619int tracing_is_enabled(void)
 620{
 621	/*
 622	 * For quick access (irqsoff uses this in fast path), just
 623	 * return the mirror variable of the state of the ring buffer.
 624	 * It's a little racy, but we don't really care.
 625	 */
 626	smp_rmb();
 627	return !global_trace.buffer_disabled;
 628}
 629
 630/*
 631 * trace_buf_size is the size in bytes that is allocated
 632 * for a buffer. Note, the number of bytes is always rounded
 633 * to page size.
 634 *
 635 * This number is purposely set to a low number of 16384.
 636 * If the dump on oops happens, it will be much appreciated
 637 * to not have to wait for all that output. Anyway this can be
 638 * boot time and run time configurable.
 639 */
 640#define TRACE_BUF_SIZE_DEFAULT	1441792UL /* 16384 * 88 (sizeof(entry)) */
 641
 642static unsigned long		trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
 643
 644/* trace_types holds a link list of available tracers. */
 645static struct tracer		*trace_types __read_mostly;
 646
 647/*
 648 * trace_types_lock is used to protect the trace_types list.
 649 */
 650DEFINE_MUTEX(trace_types_lock);
 651
 652/*
 653 * serialize the access of the ring buffer
 654 *
 655 * ring buffer serializes readers, but it is low level protection.
 656 * The validity of the events (which returns by ring_buffer_peek() ..etc)
 657 * are not protected by ring buffer.
 658 *
 659 * The content of events may become garbage if we allow other process consumes
 660 * these events concurrently:
 661 *   A) the page of the consumed events may become a normal page
 662 *      (not reader page) in ring buffer, and this page will be rewrited
 663 *      by events producer.
 664 *   B) The page of the consumed events may become a page for splice_read,
 665 *      and this page will be returned to system.
 666 *
 667 * These primitives allow multi process access to different cpu ring buffer
 668 * concurrently.
 669 *
 670 * These primitives don't distinguish read-only and read-consume access.
 671 * Multi read-only access are also serialized.
 672 */
 673
 674#ifdef CONFIG_SMP
 675static DECLARE_RWSEM(all_cpu_access_lock);
 676static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
 677
 678static inline void trace_access_lock(int cpu)
 679{
 680	if (cpu == RING_BUFFER_ALL_CPUS) {
 681		/* gain it for accessing the whole ring buffer. */
 682		down_write(&all_cpu_access_lock);
 683	} else {
 684		/* gain it for accessing a cpu ring buffer. */
 685
 686		/* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
 687		down_read(&all_cpu_access_lock);
 688
 689		/* Secondly block other access to this @cpu ring buffer. */
 690		mutex_lock(&per_cpu(cpu_access_lock, cpu));
 691	}
 692}
 693
 694static inline void trace_access_unlock(int cpu)
 695{
 696	if (cpu == RING_BUFFER_ALL_CPUS) {
 697		up_write(&all_cpu_access_lock);
 698	} else {
 699		mutex_unlock(&per_cpu(cpu_access_lock, cpu));
 700		up_read(&all_cpu_access_lock);
 701	}
 702}
 703
 704static inline void trace_access_lock_init(void)
 705{
 706	int cpu;
 707
 708	for_each_possible_cpu(cpu)
 709		mutex_init(&per_cpu(cpu_access_lock, cpu));
 710}
 711
 712#else
 713
 714static DEFINE_MUTEX(access_lock);
 715
 716static inline void trace_access_lock(int cpu)
 717{
 718	(void)cpu;
 719	mutex_lock(&access_lock);
 720}
 721
 722static inline void trace_access_unlock(int cpu)
 723{
 724	(void)cpu;
 725	mutex_unlock(&access_lock);
 726}
 727
 728static inline void trace_access_lock_init(void)
 729{
 730}
 731
 732#endif
 733
 734#ifdef CONFIG_STACKTRACE
 735static void __ftrace_trace_stack(struct ring_buffer *buffer,
 736				 unsigned long flags,
 737				 int skip, int pc, struct pt_regs *regs);
 738static inline void ftrace_trace_stack(struct trace_array *tr,
 739				      struct ring_buffer *buffer,
 740				      unsigned long flags,
 741				      int skip, int pc, struct pt_regs *regs);
 742
 743#else
 744static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
 745					unsigned long flags,
 746					int skip, int pc, struct pt_regs *regs)
 747{
 748}
 749static inline void ftrace_trace_stack(struct trace_array *tr,
 750				      struct ring_buffer *buffer,
 751				      unsigned long flags,
 752				      int skip, int pc, struct pt_regs *regs)
 753{
 754}
 755
 756#endif
 757
 758static __always_inline void
 759trace_event_setup(struct ring_buffer_event *event,
 760		  int type, unsigned long flags, int pc)
 761{
 762	struct trace_entry *ent = ring_buffer_event_data(event);
 763
 764	tracing_generic_entry_update(ent, type, flags, pc);
 765}
 766
 767static __always_inline struct ring_buffer_event *
 768__trace_buffer_lock_reserve(struct ring_buffer *buffer,
 769			  int type,
 770			  unsigned long len,
 771			  unsigned long flags, int pc)
 772{
 773	struct ring_buffer_event *event;
 774
 775	event = ring_buffer_lock_reserve(buffer, len);
 776	if (event != NULL)
 777		trace_event_setup(event, type, flags, pc);
 778
 779	return event;
 780}
 781
 782void tracer_tracing_on(struct trace_array *tr)
 783{
 784	if (tr->trace_buffer.buffer)
 785		ring_buffer_record_on(tr->trace_buffer.buffer);
 786	/*
 787	 * This flag is looked at when buffers haven't been allocated
 788	 * yet, or by some tracers (like irqsoff), that just want to
 789	 * know if the ring buffer has been disabled, but it can handle
 790	 * races of where it gets disabled but we still do a record.
 791	 * As the check is in the fast path of the tracers, it is more
 792	 * important to be fast than accurate.
 793	 */
 794	tr->buffer_disabled = 0;
 795	/* Make the flag seen by readers */
 796	smp_wmb();
 797}
 798
 799/**
 800 * tracing_on - enable tracing buffers
 801 *
 802 * This function enables tracing buffers that may have been
 803 * disabled with tracing_off.
 804 */
 805void tracing_on(void)
 806{
 807	tracer_tracing_on(&global_trace);
 808}
 809EXPORT_SYMBOL_GPL(tracing_on);
 810
 811
 812static __always_inline void
 813__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
 814{
 815	__this_cpu_write(trace_taskinfo_save, true);
 816
 817	/* If this is the temp buffer, we need to commit fully */
 818	if (this_cpu_read(trace_buffered_event) == event) {
 819		/* Length is in event->array[0] */
 820		ring_buffer_write(buffer, event->array[0], &event->array[1]);
 821		/* Release the temp buffer */
 822		this_cpu_dec(trace_buffered_event_cnt);
 823	} else
 824		ring_buffer_unlock_commit(buffer, event);
 825}
 826
 827/**
 828 * __trace_puts - write a constant string into the trace buffer.
 829 * @ip:	   The address of the caller
 830 * @str:   The constant string to write
 831 * @size:  The size of the string.
 832 */
 833int __trace_puts(unsigned long ip, const char *str, int size)
 834{
 835	struct ring_buffer_event *event;
 836	struct ring_buffer *buffer;
 837	struct print_entry *entry;
 838	unsigned long irq_flags;
 839	int alloc;
 840	int pc;
 841
 842	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
 843		return 0;
 844
 845	pc = preempt_count();
 846
 847	if (unlikely(tracing_selftest_running || tracing_disabled))
 848		return 0;
 849
 850	alloc = sizeof(*entry) + size + 2; /* possible \n added */
 851
 852	local_save_flags(irq_flags);
 853	buffer = global_trace.trace_buffer.buffer;
 854	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, 
 855					    irq_flags, pc);
 856	if (!event)
 857		return 0;
 
 
 
 858
 859	entry = ring_buffer_event_data(event);
 860	entry->ip = ip;
 861
 862	memcpy(&entry->buf, str, size);
 863
 864	/* Add a newline if necessary */
 865	if (entry->buf[size - 1] != '\n') {
 866		entry->buf[size] = '\n';
 867		entry->buf[size + 1] = '\0';
 868	} else
 869		entry->buf[size] = '\0';
 870
 871	__buffer_unlock_commit(buffer, event);
 872	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
 873
 
 874	return size;
 875}
 876EXPORT_SYMBOL_GPL(__trace_puts);
 877
 878/**
 879 * __trace_bputs - write the pointer to a constant string into trace buffer
 880 * @ip:	   The address of the caller
 881 * @str:   The constant string to write to the buffer to
 882 */
 883int __trace_bputs(unsigned long ip, const char *str)
 884{
 885	struct ring_buffer_event *event;
 886	struct ring_buffer *buffer;
 887	struct bputs_entry *entry;
 888	unsigned long irq_flags;
 889	int size = sizeof(struct bputs_entry);
 890	int pc;
 891
 892	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
 893		return 0;
 894
 895	pc = preempt_count();
 896
 897	if (unlikely(tracing_selftest_running || tracing_disabled))
 898		return 0;
 899
 900	local_save_flags(irq_flags);
 901	buffer = global_trace.trace_buffer.buffer;
 
 
 902	event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
 903					    irq_flags, pc);
 904	if (!event)
 905		return 0;
 906
 907	entry = ring_buffer_event_data(event);
 908	entry->ip			= ip;
 909	entry->str			= str;
 910
 911	__buffer_unlock_commit(buffer, event);
 912	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
 913
 914	return 1;
 
 
 
 915}
 916EXPORT_SYMBOL_GPL(__trace_bputs);
 917
 918#ifdef CONFIG_TRACER_SNAPSHOT
 919void tracing_snapshot_instance_cond(struct trace_array *tr, void *cond_data)
 
 920{
 921	struct tracer *tracer = tr->current_trace;
 922	unsigned long flags;
 923
 924	if (in_nmi()) {
 925		internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
 926		internal_trace_puts("*** snapshot is being ignored        ***\n");
 927		return;
 928	}
 929
 930	if (!tr->allocated_snapshot) {
 931		internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
 932		internal_trace_puts("*** stopping trace here!   ***\n");
 933		tracing_off();
 934		return;
 935	}
 936
 937	/* Note, snapshot can not be used when the tracer uses it */
 938	if (tracer->use_max_tr) {
 939		internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
 940		internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
 941		return;
 942	}
 943
 944	local_irq_save(flags);
 945	update_max_tr(tr, current, smp_processor_id(), cond_data);
 946	local_irq_restore(flags);
 947}
 948
 949void tracing_snapshot_instance(struct trace_array *tr)
 950{
 951	tracing_snapshot_instance_cond(tr, NULL);
 952}
 953
 954/**
 955 * tracing_snapshot - take a snapshot of the current buffer.
 956 *
 957 * This causes a swap between the snapshot buffer and the current live
 958 * tracing buffer. You can use this to take snapshots of the live
 959 * trace when some condition is triggered, but continue to trace.
 960 *
 961 * Note, make sure to allocate the snapshot with either
 962 * a tracing_snapshot_alloc(), or by doing it manually
 963 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
 964 *
 965 * If the snapshot buffer is not allocated, it will stop tracing.
 966 * Basically making a permanent snapshot.
 967 */
 968void tracing_snapshot(void)
 969{
 970	struct trace_array *tr = &global_trace;
 971
 972	tracing_snapshot_instance(tr);
 973}
 974EXPORT_SYMBOL_GPL(tracing_snapshot);
 975
 976/**
 977 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
 978 * @tr:		The tracing instance to snapshot
 979 * @cond_data:	The data to be tested conditionally, and possibly saved
 980 *
 981 * This is the same as tracing_snapshot() except that the snapshot is
 982 * conditional - the snapshot will only happen if the
 983 * cond_snapshot.update() implementation receiving the cond_data
 984 * returns true, which means that the trace array's cond_snapshot
 985 * update() operation used the cond_data to determine whether the
 986 * snapshot should be taken, and if it was, presumably saved it along
 987 * with the snapshot.
 988 */
 989void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
 990{
 991	tracing_snapshot_instance_cond(tr, cond_data);
 992}
 993EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
 994
 995/**
 996 * tracing_snapshot_cond_data - get the user data associated with a snapshot
 997 * @tr:		The tracing instance
 998 *
 999 * When the user enables a conditional snapshot using
1000 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1001 * with the snapshot.  This accessor is used to retrieve it.
1002 *
1003 * Should not be called from cond_snapshot.update(), since it takes
1004 * the tr->max_lock lock, which the code calling
1005 * cond_snapshot.update() has already done.
1006 *
1007 * Returns the cond_data associated with the trace array's snapshot.
1008 */
1009void *tracing_cond_snapshot_data(struct trace_array *tr)
1010{
1011	void *cond_data = NULL;
1012
1013	arch_spin_lock(&tr->max_lock);
1014
1015	if (tr->cond_snapshot)
1016		cond_data = tr->cond_snapshot->cond_data;
1017
1018	arch_spin_unlock(&tr->max_lock);
1019
1020	return cond_data;
1021}
1022EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1023
1024static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
1025					struct trace_buffer *size_buf, int cpu_id);
1026static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
1027
1028int tracing_alloc_snapshot_instance(struct trace_array *tr)
1029{
1030	int ret;
1031
1032	if (!tr->allocated_snapshot) {
1033
1034		/* allocate spare buffer */
1035		ret = resize_buffer_duplicate_size(&tr->max_buffer,
1036				   &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
1037		if (ret < 0)
1038			return ret;
1039
1040		tr->allocated_snapshot = true;
1041	}
1042
1043	return 0;
1044}
1045
1046static void free_snapshot(struct trace_array *tr)
1047{
1048	/*
1049	 * We don't free the ring buffer. instead, resize it because
1050	 * The max_tr ring buffer has some state (e.g. ring->clock) and
1051	 * we want preserve it.
1052	 */
1053	ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1054	set_buffer_entries(&tr->max_buffer, 1);
1055	tracing_reset_online_cpus(&tr->max_buffer);
1056	tr->allocated_snapshot = false;
1057}
1058
1059/**
1060 * tracing_alloc_snapshot - allocate snapshot buffer.
1061 *
1062 * This only allocates the snapshot buffer if it isn't already
1063 * allocated - it doesn't also take a snapshot.
1064 *
1065 * This is meant to be used in cases where the snapshot buffer needs
1066 * to be set up for events that can't sleep but need to be able to
1067 * trigger a snapshot.
1068 */
1069int tracing_alloc_snapshot(void)
1070{
1071	struct trace_array *tr = &global_trace;
1072	int ret;
1073
1074	ret = tracing_alloc_snapshot_instance(tr);
1075	WARN_ON(ret < 0);
1076
1077	return ret;
1078}
1079EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1080
1081/**
1082 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1083 *
1084 * This is similar to tracing_snapshot(), but it will allocate the
1085 * snapshot buffer if it isn't already allocated. Use this only
1086 * where it is safe to sleep, as the allocation may sleep.
1087 *
1088 * This causes a swap between the snapshot buffer and the current live
1089 * tracing buffer. You can use this to take snapshots of the live
1090 * trace when some condition is triggered, but continue to trace.
1091 */
1092void tracing_snapshot_alloc(void)
1093{
1094	int ret;
1095
1096	ret = tracing_alloc_snapshot();
1097	if (ret < 0)
1098		return;
1099
1100	tracing_snapshot();
1101}
1102EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1103
1104/**
1105 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1106 * @tr:		The tracing instance
1107 * @cond_data:	User data to associate with the snapshot
1108 * @update:	Implementation of the cond_snapshot update function
1109 *
1110 * Check whether the conditional snapshot for the given instance has
1111 * already been enabled, or if the current tracer is already using a
1112 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1113 * save the cond_data and update function inside.
1114 *
1115 * Returns 0 if successful, error otherwise.
1116 */
1117int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1118				 cond_update_fn_t update)
1119{
1120	struct cond_snapshot *cond_snapshot;
1121	int ret = 0;
1122
1123	cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1124	if (!cond_snapshot)
1125		return -ENOMEM;
1126
1127	cond_snapshot->cond_data = cond_data;
1128	cond_snapshot->update = update;
1129
1130	mutex_lock(&trace_types_lock);
1131
1132	ret = tracing_alloc_snapshot_instance(tr);
1133	if (ret)
1134		goto fail_unlock;
1135
1136	if (tr->current_trace->use_max_tr) {
1137		ret = -EBUSY;
1138		goto fail_unlock;
1139	}
1140
1141	/*
1142	 * The cond_snapshot can only change to NULL without the
1143	 * trace_types_lock. We don't care if we race with it going
1144	 * to NULL, but we want to make sure that it's not set to
1145	 * something other than NULL when we get here, which we can
1146	 * do safely with only holding the trace_types_lock and not
1147	 * having to take the max_lock.
1148	 */
1149	if (tr->cond_snapshot) {
1150		ret = -EBUSY;
1151		goto fail_unlock;
1152	}
1153
1154	arch_spin_lock(&tr->max_lock);
1155	tr->cond_snapshot = cond_snapshot;
1156	arch_spin_unlock(&tr->max_lock);
1157
1158	mutex_unlock(&trace_types_lock);
1159
1160	return ret;
1161
1162 fail_unlock:
1163	mutex_unlock(&trace_types_lock);
1164	kfree(cond_snapshot);
1165	return ret;
1166}
1167EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1168
1169/**
1170 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1171 * @tr:		The tracing instance
1172 *
1173 * Check whether the conditional snapshot for the given instance is
1174 * enabled; if so, free the cond_snapshot associated with it,
1175 * otherwise return -EINVAL.
1176 *
1177 * Returns 0 if successful, error otherwise.
1178 */
1179int tracing_snapshot_cond_disable(struct trace_array *tr)
1180{
1181	int ret = 0;
1182
1183	arch_spin_lock(&tr->max_lock);
1184
1185	if (!tr->cond_snapshot)
1186		ret = -EINVAL;
1187	else {
1188		kfree(tr->cond_snapshot);
1189		tr->cond_snapshot = NULL;
1190	}
1191
1192	arch_spin_unlock(&tr->max_lock);
1193
1194	return ret;
1195}
1196EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1197#else
1198void tracing_snapshot(void)
1199{
1200	WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1201}
1202EXPORT_SYMBOL_GPL(tracing_snapshot);
1203void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1204{
1205	WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1206}
1207EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1208int tracing_alloc_snapshot(void)
1209{
1210	WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1211	return -ENODEV;
1212}
1213EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1214void tracing_snapshot_alloc(void)
1215{
1216	/* Give warning */
1217	tracing_snapshot();
1218}
1219EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1220void *tracing_cond_snapshot_data(struct trace_array *tr)
1221{
1222	return NULL;
1223}
1224EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1225int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1226{
1227	return -ENODEV;
1228}
1229EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1230int tracing_snapshot_cond_disable(struct trace_array *tr)
1231{
1232	return false;
1233}
1234EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1235#endif /* CONFIG_TRACER_SNAPSHOT */
1236
1237void tracer_tracing_off(struct trace_array *tr)
1238{
1239	if (tr->trace_buffer.buffer)
1240		ring_buffer_record_off(tr->trace_buffer.buffer);
1241	/*
1242	 * This flag is looked at when buffers haven't been allocated
1243	 * yet, or by some tracers (like irqsoff), that just want to
1244	 * know if the ring buffer has been disabled, but it can handle
1245	 * races of where it gets disabled but we still do a record.
1246	 * As the check is in the fast path of the tracers, it is more
1247	 * important to be fast than accurate.
1248	 */
1249	tr->buffer_disabled = 1;
1250	/* Make the flag seen by readers */
1251	smp_wmb();
1252}
1253
1254/**
1255 * tracing_off - turn off tracing buffers
1256 *
1257 * This function stops the tracing buffers from recording data.
1258 * It does not disable any overhead the tracers themselves may
1259 * be causing. This function simply causes all recording to
1260 * the ring buffers to fail.
1261 */
1262void tracing_off(void)
1263{
1264	tracer_tracing_off(&global_trace);
1265}
1266EXPORT_SYMBOL_GPL(tracing_off);
1267
1268void disable_trace_on_warning(void)
1269{
1270	if (__disable_trace_on_warning)
 
 
1271		tracing_off();
 
1272}
1273
1274/**
1275 * tracer_tracing_is_on - show real state of ring buffer enabled
1276 * @tr : the trace array to know if ring buffer is enabled
1277 *
1278 * Shows real state of the ring buffer if it is enabled or not.
1279 */
1280bool tracer_tracing_is_on(struct trace_array *tr)
1281{
1282	if (tr->trace_buffer.buffer)
1283		return ring_buffer_record_is_on(tr->trace_buffer.buffer);
1284	return !tr->buffer_disabled;
1285}
1286
1287/**
1288 * tracing_is_on - show state of ring buffers enabled
1289 */
1290int tracing_is_on(void)
1291{
1292	return tracer_tracing_is_on(&global_trace);
1293}
1294EXPORT_SYMBOL_GPL(tracing_is_on);
1295
1296static int __init set_buf_size(char *str)
1297{
1298	unsigned long buf_size;
1299
1300	if (!str)
1301		return 0;
1302	buf_size = memparse(str, &str);
1303	/* nr_entries can not be zero */
1304	if (buf_size == 0)
1305		return 0;
1306	trace_buf_size = buf_size;
1307	return 1;
1308}
1309__setup("trace_buf_size=", set_buf_size);
1310
1311static int __init set_tracing_thresh(char *str)
1312{
1313	unsigned long threshold;
1314	int ret;
1315
1316	if (!str)
1317		return 0;
1318	ret = kstrtoul(str, 0, &threshold);
1319	if (ret < 0)
1320		return 0;
1321	tracing_thresh = threshold * 1000;
1322	return 1;
1323}
1324__setup("tracing_thresh=", set_tracing_thresh);
1325
1326unsigned long nsecs_to_usecs(unsigned long nsecs)
1327{
1328	return nsecs / 1000;
1329}
1330
1331/*
1332 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1333 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1334 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1335 * of strings in the order that the evals (enum) were defined.
1336 */
1337#undef C
1338#define C(a, b) b
1339
1340/* These must match the bit postions in trace_iterator_flags */
1341static const char *trace_options[] = {
1342	TRACE_FLAGS
1343	NULL
1344};
1345
1346static struct {
1347	u64 (*func)(void);
1348	const char *name;
1349	int in_ns;		/* is this clock in nanoseconds? */
1350} trace_clocks[] = {
1351	{ trace_clock_local,		"local",	1 },
1352	{ trace_clock_global,		"global",	1 },
1353	{ trace_clock_counter,		"counter",	0 },
1354	{ trace_clock_jiffies,		"uptime",	0 },
1355	{ trace_clock,			"perf",		1 },
1356	{ ktime_get_mono_fast_ns,	"mono",		1 },
1357	{ ktime_get_raw_fast_ns,	"mono_raw",	1 },
1358	{ ktime_get_boot_fast_ns,	"boot",		1 },
1359	ARCH_TRACE_CLOCKS
1360};
1361
1362bool trace_clock_in_ns(struct trace_array *tr)
1363{
1364	if (trace_clocks[tr->clock_id].in_ns)
1365		return true;
1366
1367	return false;
1368}
1369
1370/*
1371 * trace_parser_get_init - gets the buffer for trace parser
1372 */
1373int trace_parser_get_init(struct trace_parser *parser, int size)
1374{
1375	memset(parser, 0, sizeof(*parser));
1376
1377	parser->buffer = kmalloc(size, GFP_KERNEL);
1378	if (!parser->buffer)
1379		return 1;
1380
1381	parser->size = size;
1382	return 0;
1383}
1384
1385/*
1386 * trace_parser_put - frees the buffer for trace parser
1387 */
1388void trace_parser_put(struct trace_parser *parser)
1389{
1390	kfree(parser->buffer);
1391	parser->buffer = NULL;
1392}
1393
1394/*
1395 * trace_get_user - reads the user input string separated by  space
1396 * (matched by isspace(ch))
1397 *
1398 * For each string found the 'struct trace_parser' is updated,
1399 * and the function returns.
1400 *
1401 * Returns number of bytes read.
1402 *
1403 * See kernel/trace/trace.h for 'struct trace_parser' details.
1404 */
1405int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1406	size_t cnt, loff_t *ppos)
1407{
1408	char ch;
1409	size_t read = 0;
1410	ssize_t ret;
1411
1412	if (!*ppos)
1413		trace_parser_clear(parser);
1414
1415	ret = get_user(ch, ubuf++);
1416	if (ret)
1417		goto out;
1418
1419	read++;
1420	cnt--;
1421
1422	/*
1423	 * The parser is not finished with the last write,
1424	 * continue reading the user input without skipping spaces.
1425	 */
1426	if (!parser->cont) {
1427		/* skip white space */
1428		while (cnt && isspace(ch)) {
1429			ret = get_user(ch, ubuf++);
1430			if (ret)
1431				goto out;
1432			read++;
1433			cnt--;
1434		}
1435
1436		parser->idx = 0;
1437
1438		/* only spaces were written */
1439		if (isspace(ch) || !ch) {
1440			*ppos += read;
1441			ret = read;
1442			goto out;
1443		}
1444	}
1445
1446	/* read the non-space input */
1447	while (cnt && !isspace(ch) && ch) {
1448		if (parser->idx < parser->size - 1)
1449			parser->buffer[parser->idx++] = ch;
1450		else {
1451			ret = -EINVAL;
1452			goto out;
1453		}
1454		ret = get_user(ch, ubuf++);
1455		if (ret)
1456			goto out;
1457		read++;
1458		cnt--;
1459	}
1460
1461	/* We either got finished input or we have to wait for another call. */
1462	if (isspace(ch) || !ch) {
1463		parser->buffer[parser->idx] = 0;
1464		parser->cont = false;
1465	} else if (parser->idx < parser->size - 1) {
1466		parser->cont = true;
1467		parser->buffer[parser->idx++] = ch;
1468		/* Make sure the parsed string always terminates with '\0'. */
1469		parser->buffer[parser->idx] = 0;
1470	} else {
1471		ret = -EINVAL;
1472		goto out;
1473	}
1474
1475	*ppos += read;
1476	ret = read;
1477
1478out:
1479	return ret;
1480}
1481
1482/* TODO add a seq_buf_to_buffer() */
1483static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1484{
1485	int len;
1486
1487	if (trace_seq_used(s) <= s->seq.readpos)
1488		return -EBUSY;
1489
1490	len = trace_seq_used(s) - s->seq.readpos;
1491	if (cnt > len)
1492		cnt = len;
1493	memcpy(buf, s->buffer + s->seq.readpos, cnt);
1494
1495	s->seq.readpos += cnt;
1496	return cnt;
1497}
1498
1499unsigned long __read_mostly	tracing_thresh;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1500
1501#ifdef CONFIG_TRACER_MAX_TRACE
1502/*
1503 * Copy the new maximum trace into the separate maximum-trace
1504 * structure. (this way the maximum trace is permanently saved,
1505 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1506 */
1507static void
1508__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1509{
1510	struct trace_buffer *trace_buf = &tr->trace_buffer;
1511	struct trace_buffer *max_buf = &tr->max_buffer;
1512	struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1513	struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1514
1515	max_buf->cpu = cpu;
1516	max_buf->time_start = data->preempt_timestamp;
1517
1518	max_data->saved_latency = tr->max_latency;
1519	max_data->critical_start = data->critical_start;
1520	max_data->critical_end = data->critical_end;
1521
1522	strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1523	max_data->pid = tsk->pid;
1524	/*
1525	 * If tsk == current, then use current_uid(), as that does not use
1526	 * RCU. The irq tracer can be called out of RCU scope.
1527	 */
1528	if (tsk == current)
1529		max_data->uid = current_uid();
1530	else
1531		max_data->uid = task_uid(tsk);
1532
1533	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1534	max_data->policy = tsk->policy;
1535	max_data->rt_priority = tsk->rt_priority;
1536
1537	/* record this tasks comm */
1538	tracing_record_cmdline(tsk);
 
1539}
1540
1541/**
1542 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1543 * @tr: tracer
1544 * @tsk: the task with the latency
1545 * @cpu: The cpu that initiated the trace.
1546 * @cond_data: User data associated with a conditional snapshot
1547 *
1548 * Flip the buffers between the @tr and the max_tr and record information
1549 * about which task was the cause of this latency.
1550 */
1551void
1552update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1553	      void *cond_data)
1554{
1555	if (tr->stop_count)
1556		return;
1557
1558	WARN_ON_ONCE(!irqs_disabled());
1559
1560	if (!tr->allocated_snapshot) {
1561		/* Only the nop tracer should hit this when disabling */
1562		WARN_ON_ONCE(tr->current_trace != &nop_trace);
1563		return;
1564	}
1565
1566	arch_spin_lock(&tr->max_lock);
1567
1568	/* Inherit the recordable setting from trace_buffer */
1569	if (ring_buffer_record_is_set_on(tr->trace_buffer.buffer))
1570		ring_buffer_record_on(tr->max_buffer.buffer);
1571	else
1572		ring_buffer_record_off(tr->max_buffer.buffer);
1573
1574#ifdef CONFIG_TRACER_SNAPSHOT
1575	if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data))
1576		goto out_unlock;
1577#endif
1578	swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
1579
1580	__update_max_tr(tr, tsk, cpu);
1581
1582 out_unlock:
1583	arch_spin_unlock(&tr->max_lock);
1584}
1585
1586/**
1587 * update_max_tr_single - only copy one trace over, and reset the rest
1588 * @tr: tracer
1589 * @tsk: task with the latency
1590 * @cpu: the cpu of the buffer to copy.
1591 *
1592 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1593 */
1594void
1595update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1596{
1597	int ret;
1598
1599	if (tr->stop_count)
1600		return;
1601
1602	WARN_ON_ONCE(!irqs_disabled());
1603	if (!tr->allocated_snapshot) {
1604		/* Only the nop tracer should hit this when disabling */
1605		WARN_ON_ONCE(tr->current_trace != &nop_trace);
1606		return;
1607	}
1608
1609	arch_spin_lock(&tr->max_lock);
1610
1611	ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1612
1613	if (ret == -EBUSY) {
1614		/*
1615		 * We failed to swap the buffer due to a commit taking
1616		 * place on this CPU. We fail to record, but we reset
1617		 * the max trace buffer (no one writes directly to it)
1618		 * and flag that it failed.
1619		 */
1620		trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1621			"Failed to swap buffers due to commit in progress\n");
1622	}
1623
1624	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1625
1626	__update_max_tr(tr, tsk, cpu);
1627	arch_spin_unlock(&tr->max_lock);
1628}
1629#endif /* CONFIG_TRACER_MAX_TRACE */
1630
1631static int wait_on_pipe(struct trace_iterator *iter, int full)
1632{
1633	/* Iterators are static, they should be filled or empty */
1634	if (trace_buffer_iter(iter, iter->cpu_file))
1635		return 0;
1636
1637	return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
1638				full);
1639}
1640
1641#ifdef CONFIG_FTRACE_STARTUP_TEST
1642static bool selftests_can_run;
1643
1644struct trace_selftests {
1645	struct list_head		list;
1646	struct tracer			*type;
1647};
1648
1649static LIST_HEAD(postponed_selftests);
1650
1651static int save_selftest(struct tracer *type)
1652{
1653	struct trace_selftests *selftest;
1654
1655	selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1656	if (!selftest)
1657		return -ENOMEM;
1658
1659	selftest->type = type;
1660	list_add(&selftest->list, &postponed_selftests);
1661	return 0;
1662}
1663
1664static int run_tracer_selftest(struct tracer *type)
1665{
1666	struct trace_array *tr = &global_trace;
1667	struct tracer *saved_tracer = tr->current_trace;
1668	int ret;
1669
1670	if (!type->selftest || tracing_selftest_disabled)
1671		return 0;
1672
1673	/*
1674	 * If a tracer registers early in boot up (before scheduling is
1675	 * initialized and such), then do not run its selftests yet.
1676	 * Instead, run it a little later in the boot process.
1677	 */
1678	if (!selftests_can_run)
1679		return save_selftest(type);
1680
 
 
 
 
 
 
1681	/*
1682	 * Run a selftest on this tracer.
1683	 * Here we reset the trace buffer, and set the current
1684	 * tracer to be this tracer. The tracer can then run some
1685	 * internal tracing to verify that everything is in order.
1686	 * If we fail, we do not register this tracer.
1687	 */
1688	tracing_reset_online_cpus(&tr->trace_buffer);
1689
1690	tr->current_trace = type;
1691
1692#ifdef CONFIG_TRACER_MAX_TRACE
1693	if (type->use_max_tr) {
1694		/* If we expanded the buffers, make sure the max is expanded too */
1695		if (ring_buffer_expanded)
1696			ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1697					   RING_BUFFER_ALL_CPUS);
1698		tr->allocated_snapshot = true;
1699	}
1700#endif
1701
1702	/* the test is responsible for initializing and enabling */
1703	pr_info("Testing tracer %s: ", type->name);
1704	ret = type->selftest(type, tr);
1705	/* the test is responsible for resetting too */
1706	tr->current_trace = saved_tracer;
1707	if (ret) {
1708		printk(KERN_CONT "FAILED!\n");
1709		/* Add the warning after printing 'FAILED' */
1710		WARN_ON(1);
1711		return -1;
1712	}
1713	/* Only reset on passing, to avoid touching corrupted buffers */
1714	tracing_reset_online_cpus(&tr->trace_buffer);
1715
1716#ifdef CONFIG_TRACER_MAX_TRACE
1717	if (type->use_max_tr) {
1718		tr->allocated_snapshot = false;
1719
1720		/* Shrink the max buffer again */
1721		if (ring_buffer_expanded)
1722			ring_buffer_resize(tr->max_buffer.buffer, 1,
1723					   RING_BUFFER_ALL_CPUS);
1724	}
1725#endif
1726
1727	printk(KERN_CONT "PASSED\n");
1728	return 0;
1729}
1730
1731static __init int init_trace_selftests(void)
1732{
1733	struct trace_selftests *p, *n;
1734	struct tracer *t, **last;
1735	int ret;
1736
1737	selftests_can_run = true;
1738
1739	mutex_lock(&trace_types_lock);
1740
1741	if (list_empty(&postponed_selftests))
1742		goto out;
1743
1744	pr_info("Running postponed tracer tests:\n");
1745
 
1746	list_for_each_entry_safe(p, n, &postponed_selftests, list) {
1747		/* This loop can take minutes when sanitizers are enabled, so
1748		 * lets make sure we allow RCU processing.
1749		 */
1750		cond_resched();
1751		ret = run_tracer_selftest(p->type);
1752		/* If the test fails, then warn and remove from available_tracers */
1753		if (ret < 0) {
1754			WARN(1, "tracer: %s failed selftest, disabling\n",
1755			     p->type->name);
1756			last = &trace_types;
1757			for (t = trace_types; t; t = t->next) {
1758				if (t == p->type) {
1759					*last = t->next;
1760					break;
1761				}
1762				last = &t->next;
1763			}
1764		}
1765		list_del(&p->list);
1766		kfree(p);
1767	}
 
1768
1769 out:
1770	mutex_unlock(&trace_types_lock);
1771
1772	return 0;
1773}
1774core_initcall(init_trace_selftests);
1775#else
1776static inline int run_tracer_selftest(struct tracer *type)
1777{
1778	return 0;
1779}
1780#endif /* CONFIG_FTRACE_STARTUP_TEST */
1781
1782static void add_tracer_options(struct trace_array *tr, struct tracer *t);
1783
1784static void __init apply_trace_boot_options(void);
1785
1786/**
1787 * register_tracer - register a tracer with the ftrace system.
1788 * @type: the plugin for the tracer
1789 *
1790 * Register a new plugin tracer.
1791 */
1792int __init register_tracer(struct tracer *type)
1793{
1794	struct tracer *t;
1795	int ret = 0;
1796
1797	if (!type->name) {
1798		pr_info("Tracer must have a name\n");
1799		return -1;
1800	}
1801
1802	if (strlen(type->name) >= MAX_TRACER_SIZE) {
1803		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1804		return -1;
1805	}
1806
 
 
 
 
 
 
1807	mutex_lock(&trace_types_lock);
1808
1809	tracing_selftest_running = true;
1810
1811	for (t = trace_types; t; t = t->next) {
1812		if (strcmp(type->name, t->name) == 0) {
1813			/* already found */
1814			pr_info("Tracer %s already registered\n",
1815				type->name);
1816			ret = -1;
1817			goto out;
1818		}
1819	}
1820
1821	if (!type->set_flag)
1822		type->set_flag = &dummy_set_flag;
1823	if (!type->flags) {
1824		/*allocate a dummy tracer_flags*/
1825		type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
1826		if (!type->flags) {
1827			ret = -ENOMEM;
1828			goto out;
1829		}
1830		type->flags->val = 0;
1831		type->flags->opts = dummy_tracer_opt;
1832	} else
1833		if (!type->flags->opts)
1834			type->flags->opts = dummy_tracer_opt;
1835
1836	/* store the tracer for __set_tracer_option */
1837	type->flags->trace = type;
1838
1839	ret = run_tracer_selftest(type);
1840	if (ret < 0)
1841		goto out;
1842
1843	type->next = trace_types;
1844	trace_types = type;
1845	add_tracer_options(&global_trace, type);
1846
1847 out:
1848	tracing_selftest_running = false;
1849	mutex_unlock(&trace_types_lock);
1850
1851	if (ret || !default_bootup_tracer)
1852		goto out_unlock;
1853
1854	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1855		goto out_unlock;
1856
1857	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1858	/* Do we want this tracer to start on bootup? */
1859	tracing_set_tracer(&global_trace, type->name);
1860	default_bootup_tracer = NULL;
1861
1862	apply_trace_boot_options();
1863
1864	/* disable other selftests, since this will break it. */
1865	tracing_selftest_disabled = true;
1866#ifdef CONFIG_FTRACE_STARTUP_TEST
1867	printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1868	       type->name);
1869#endif
1870
1871 out_unlock:
1872	return ret;
1873}
1874
1875static void tracing_reset_cpu(struct trace_buffer *buf, int cpu)
1876{
1877	struct ring_buffer *buffer = buf->buffer;
1878
1879	if (!buffer)
1880		return;
1881
1882	ring_buffer_record_disable(buffer);
1883
1884	/* Make sure all commits have finished */
1885	synchronize_rcu();
1886	ring_buffer_reset_cpu(buffer, cpu);
1887
1888	ring_buffer_record_enable(buffer);
1889}
1890
1891void tracing_reset_online_cpus(struct trace_buffer *buf)
1892{
1893	struct ring_buffer *buffer = buf->buffer;
1894	int cpu;
1895
1896	if (!buffer)
1897		return;
1898
1899	ring_buffer_record_disable(buffer);
1900
1901	/* Make sure all commits have finished */
1902	synchronize_rcu();
1903
1904	buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1905
1906	for_each_online_cpu(cpu)
1907		ring_buffer_reset_cpu(buffer, cpu);
1908
1909	ring_buffer_record_enable(buffer);
1910}
1911
1912/* Must have trace_types_lock held */
1913void tracing_reset_all_online_cpus(void)
1914{
1915	struct trace_array *tr;
1916
1917	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1918		if (!tr->clear_trace)
1919			continue;
1920		tr->clear_trace = false;
1921		tracing_reset_online_cpus(&tr->trace_buffer);
1922#ifdef CONFIG_TRACER_MAX_TRACE
1923		tracing_reset_online_cpus(&tr->max_buffer);
1924#endif
1925	}
1926}
1927
 
 
 
 
1928static int *tgid_map;
1929
 
 
 
1930#define SAVED_CMDLINES_DEFAULT 128
1931#define NO_CMDLINE_MAP UINT_MAX
1932static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1933struct saved_cmdlines_buffer {
1934	unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1935	unsigned *map_cmdline_to_pid;
1936	unsigned cmdline_num;
1937	int cmdline_idx;
1938	char *saved_cmdlines;
1939};
1940static struct saved_cmdlines_buffer *savedcmd;
1941
1942/* temporary disable recording */
1943static atomic_t trace_record_taskinfo_disabled __read_mostly;
1944
1945static inline char *get_saved_cmdlines(int idx)
1946{
1947	return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
1948}
1949
1950static inline void set_cmdline(int idx, const char *cmdline)
1951{
1952	strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
1953}
1954
1955static int allocate_cmdlines_buffer(unsigned int val,
1956				    struct saved_cmdlines_buffer *s)
1957{
1958	s->map_cmdline_to_pid = kmalloc_array(val,
1959					      sizeof(*s->map_cmdline_to_pid),
1960					      GFP_KERNEL);
1961	if (!s->map_cmdline_to_pid)
1962		return -ENOMEM;
1963
1964	s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
1965	if (!s->saved_cmdlines) {
1966		kfree(s->map_cmdline_to_pid);
1967		return -ENOMEM;
1968	}
1969
1970	s->cmdline_idx = 0;
1971	s->cmdline_num = val;
1972	memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
1973	       sizeof(s->map_pid_to_cmdline));
1974	memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
1975	       val * sizeof(*s->map_cmdline_to_pid));
1976
1977	return 0;
1978}
1979
1980static int trace_create_savedcmd(void)
1981{
1982	int ret;
1983
1984	savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
1985	if (!savedcmd)
1986		return -ENOMEM;
1987
1988	ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
1989	if (ret < 0) {
1990		kfree(savedcmd);
1991		savedcmd = NULL;
1992		return -ENOMEM;
1993	}
1994
1995	return 0;
1996}
1997
1998int is_tracing_stopped(void)
1999{
2000	return global_trace.stop_count;
2001}
2002
2003/**
2004 * tracing_start - quick start of the tracer
2005 *
2006 * If tracing is enabled but was stopped by tracing_stop,
2007 * this will start the tracer back up.
2008 */
2009void tracing_start(void)
2010{
2011	struct ring_buffer *buffer;
2012	unsigned long flags;
2013
2014	if (tracing_disabled)
2015		return;
2016
2017	raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2018	if (--global_trace.stop_count) {
2019		if (global_trace.stop_count < 0) {
2020			/* Someone screwed up their debugging */
2021			WARN_ON_ONCE(1);
2022			global_trace.stop_count = 0;
2023		}
2024		goto out;
2025	}
2026
2027	/* Prevent the buffers from switching */
2028	arch_spin_lock(&global_trace.max_lock);
2029
2030	buffer = global_trace.trace_buffer.buffer;
2031	if (buffer)
2032		ring_buffer_record_enable(buffer);
2033
2034#ifdef CONFIG_TRACER_MAX_TRACE
2035	buffer = global_trace.max_buffer.buffer;
2036	if (buffer)
2037		ring_buffer_record_enable(buffer);
2038#endif
2039
2040	arch_spin_unlock(&global_trace.max_lock);
2041
2042 out:
2043	raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2044}
2045
2046static void tracing_start_tr(struct trace_array *tr)
2047{
2048	struct ring_buffer *buffer;
2049	unsigned long flags;
2050
2051	if (tracing_disabled)
2052		return;
2053
2054	/* If global, we need to also start the max tracer */
2055	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2056		return tracing_start();
2057
2058	raw_spin_lock_irqsave(&tr->start_lock, flags);
2059
2060	if (--tr->stop_count) {
2061		if (tr->stop_count < 0) {
2062			/* Someone screwed up their debugging */
2063			WARN_ON_ONCE(1);
2064			tr->stop_count = 0;
2065		}
2066		goto out;
2067	}
2068
2069	buffer = tr->trace_buffer.buffer;
2070	if (buffer)
2071		ring_buffer_record_enable(buffer);
2072
2073 out:
2074	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2075}
2076
2077/**
2078 * tracing_stop - quick stop of the tracer
2079 *
2080 * Light weight way to stop tracing. Use in conjunction with
2081 * tracing_start.
2082 */
2083void tracing_stop(void)
2084{
2085	struct ring_buffer *buffer;
2086	unsigned long flags;
2087
2088	raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2089	if (global_trace.stop_count++)
2090		goto out;
2091
2092	/* Prevent the buffers from switching */
2093	arch_spin_lock(&global_trace.max_lock);
2094
2095	buffer = global_trace.trace_buffer.buffer;
2096	if (buffer)
2097		ring_buffer_record_disable(buffer);
2098
2099#ifdef CONFIG_TRACER_MAX_TRACE
2100	buffer = global_trace.max_buffer.buffer;
2101	if (buffer)
2102		ring_buffer_record_disable(buffer);
2103#endif
2104
2105	arch_spin_unlock(&global_trace.max_lock);
2106
2107 out:
2108	raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2109}
2110
2111static void tracing_stop_tr(struct trace_array *tr)
2112{
2113	struct ring_buffer *buffer;
2114	unsigned long flags;
2115
2116	/* If global, we need to also stop the max tracer */
2117	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2118		return tracing_stop();
2119
2120	raw_spin_lock_irqsave(&tr->start_lock, flags);
2121	if (tr->stop_count++)
2122		goto out;
2123
2124	buffer = tr->trace_buffer.buffer;
2125	if (buffer)
2126		ring_buffer_record_disable(buffer);
2127
2128 out:
2129	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2130}
2131
2132static int trace_save_cmdline(struct task_struct *tsk)
2133{
2134	unsigned pid, idx;
2135
2136	/* treat recording of idle task as a success */
2137	if (!tsk->pid)
2138		return 1;
2139
2140	if (unlikely(tsk->pid > PID_MAX_DEFAULT))
2141		return 0;
2142
2143	/*
2144	 * It's not the end of the world if we don't get
2145	 * the lock, but we also don't want to spin
2146	 * nor do we want to disable interrupts,
2147	 * so if we miss here, then better luck next time.
2148	 */
2149	if (!arch_spin_trylock(&trace_cmdline_lock))
2150		return 0;
2151
2152	idx = savedcmd->map_pid_to_cmdline[tsk->pid];
2153	if (idx == NO_CMDLINE_MAP) {
2154		idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
2155
2156		/*
2157		 * Check whether the cmdline buffer at idx has a pid
2158		 * mapped. We are going to overwrite that entry so we
2159		 * need to clear the map_pid_to_cmdline. Otherwise we
2160		 * would read the new comm for the old pid.
2161		 */
2162		pid = savedcmd->map_cmdline_to_pid[idx];
2163		if (pid != NO_CMDLINE_MAP)
2164			savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
2165
2166		savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
2167		savedcmd->map_pid_to_cmdline[tsk->pid] = idx;
2168
2169		savedcmd->cmdline_idx = idx;
2170	}
2171
 
2172	set_cmdline(idx, tsk->comm);
2173
2174	arch_spin_unlock(&trace_cmdline_lock);
2175
2176	return 1;
2177}
2178
2179static void __trace_find_cmdline(int pid, char comm[])
2180{
2181	unsigned map;
 
2182
2183	if (!pid) {
2184		strcpy(comm, "<idle>");
2185		return;
2186	}
2187
2188	if (WARN_ON_ONCE(pid < 0)) {
2189		strcpy(comm, "<XXX>");
2190		return;
2191	}
2192
2193	if (pid > PID_MAX_DEFAULT) {
2194		strcpy(comm, "<...>");
2195		return;
 
 
 
 
 
2196	}
2197
2198	map = savedcmd->map_pid_to_cmdline[pid];
2199	if (map != NO_CMDLINE_MAP)
2200		strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2201	else
2202		strcpy(comm, "<...>");
2203}
2204
2205void trace_find_cmdline(int pid, char comm[])
2206{
2207	preempt_disable();
2208	arch_spin_lock(&trace_cmdline_lock);
2209
2210	__trace_find_cmdline(pid, comm);
2211
2212	arch_spin_unlock(&trace_cmdline_lock);
2213	preempt_enable();
2214}
2215
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2216int trace_find_tgid(int pid)
2217{
2218	if (unlikely(!tgid_map || !pid || pid > PID_MAX_DEFAULT))
2219		return 0;
2220
2221	return tgid_map[pid];
2222}
2223
2224static int trace_save_tgid(struct task_struct *tsk)
2225{
 
 
2226	/* treat recording of idle task as a success */
2227	if (!tsk->pid)
2228		return 1;
2229
2230	if (unlikely(!tgid_map || tsk->pid > PID_MAX_DEFAULT))
 
2231		return 0;
2232
2233	tgid_map[tsk->pid] = tsk->tgid;
2234	return 1;
2235}
2236
2237static bool tracing_record_taskinfo_skip(int flags)
2238{
2239	if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2240		return true;
2241	if (atomic_read(&trace_record_taskinfo_disabled) || !tracing_is_on())
2242		return true;
2243	if (!__this_cpu_read(trace_taskinfo_save))
2244		return true;
2245	return false;
2246}
2247
2248/**
2249 * tracing_record_taskinfo - record the task info of a task
2250 *
2251 * @task:  task to record
2252 * @flags: TRACE_RECORD_CMDLINE for recording comm
2253 *         TRACE_RECORD_TGID for recording tgid
2254 */
2255void tracing_record_taskinfo(struct task_struct *task, int flags)
2256{
2257	bool done;
2258
2259	if (tracing_record_taskinfo_skip(flags))
2260		return;
2261
2262	/*
2263	 * Record as much task information as possible. If some fail, continue
2264	 * to try to record the others.
2265	 */
2266	done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2267	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2268
2269	/* If recording any information failed, retry again soon. */
2270	if (!done)
2271		return;
2272
2273	__this_cpu_write(trace_taskinfo_save, false);
2274}
2275
2276/**
2277 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2278 *
2279 * @prev: previous task during sched_switch
2280 * @next: next task during sched_switch
2281 * @flags: TRACE_RECORD_CMDLINE for recording comm
2282 *         TRACE_RECORD_TGID for recording tgid
2283 */
2284void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2285					  struct task_struct *next, int flags)
2286{
2287	bool done;
2288
2289	if (tracing_record_taskinfo_skip(flags))
2290		return;
2291
2292	/*
2293	 * Record as much task information as possible. If some fail, continue
2294	 * to try to record the others.
2295	 */
2296	done  = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2297	done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2298	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2299	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2300
2301	/* If recording any information failed, retry again soon. */
2302	if (!done)
2303		return;
2304
2305	__this_cpu_write(trace_taskinfo_save, false);
2306}
2307
2308/* Helpers to record a specific task information */
2309void tracing_record_cmdline(struct task_struct *task)
2310{
2311	tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2312}
2313
2314void tracing_record_tgid(struct task_struct *task)
2315{
2316	tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2317}
2318
2319/*
2320 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2321 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2322 * simplifies those functions and keeps them in sync.
2323 */
2324enum print_line_t trace_handle_return(struct trace_seq *s)
2325{
2326	return trace_seq_has_overflowed(s) ?
2327		TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2328}
2329EXPORT_SYMBOL_GPL(trace_handle_return);
2330
2331void
2332tracing_generic_entry_update(struct trace_entry *entry, unsigned short type,
2333			     unsigned long flags, int pc)
2334{
2335	struct task_struct *tsk = current;
 
2336
2337	entry->preempt_count		= pc & 0xff;
2338	entry->pid			= (tsk) ? tsk->pid : 0;
2339	entry->type			= type;
2340	entry->flags =
2341#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
2342		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
2343#else
2344		TRACE_FLAG_IRQS_NOSUPPORT |
2345#endif
2346		((pc & NMI_MASK    ) ? TRACE_FLAG_NMI     : 0) |
2347		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
2348		((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
2349		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
2350		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
2351}
2352EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
2353
2354struct ring_buffer_event *
2355trace_buffer_lock_reserve(struct ring_buffer *buffer,
2356			  int type,
2357			  unsigned long len,
2358			  unsigned long flags, int pc)
2359{
2360	return __trace_buffer_lock_reserve(buffer, type, len, flags, pc);
2361}
2362
2363DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2364DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2365static int trace_buffered_event_ref;
2366
2367/**
2368 * trace_buffered_event_enable - enable buffering events
2369 *
2370 * When events are being filtered, it is quicker to use a temporary
2371 * buffer to write the event data into if there's a likely chance
2372 * that it will not be committed. The discard of the ring buffer
2373 * is not as fast as committing, and is much slower than copying
2374 * a commit.
2375 *
2376 * When an event is to be filtered, allocate per cpu buffers to
2377 * write the event data into, and if the event is filtered and discarded
2378 * it is simply dropped, otherwise, the entire data is to be committed
2379 * in one shot.
2380 */
2381void trace_buffered_event_enable(void)
2382{
2383	struct ring_buffer_event *event;
2384	struct page *page;
2385	int cpu;
2386
2387	WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2388
2389	if (trace_buffered_event_ref++)
2390		return;
2391
2392	for_each_tracing_cpu(cpu) {
2393		page = alloc_pages_node(cpu_to_node(cpu),
2394					GFP_KERNEL | __GFP_NORETRY, 0);
2395		if (!page)
2396			goto failed;
2397
2398		event = page_address(page);
2399		memset(event, 0, sizeof(*event));
2400
2401		per_cpu(trace_buffered_event, cpu) = event;
2402
2403		preempt_disable();
2404		if (cpu == smp_processor_id() &&
2405		    this_cpu_read(trace_buffered_event) !=
2406		    per_cpu(trace_buffered_event, cpu))
2407			WARN_ON_ONCE(1);
2408		preempt_enable();
2409	}
2410
2411	return;
2412 failed:
2413	trace_buffered_event_disable();
2414}
2415
2416static void enable_trace_buffered_event(void *data)
2417{
2418	/* Probably not needed, but do it anyway */
2419	smp_rmb();
2420	this_cpu_dec(trace_buffered_event_cnt);
2421}
2422
2423static void disable_trace_buffered_event(void *data)
2424{
2425	this_cpu_inc(trace_buffered_event_cnt);
2426}
2427
2428/**
2429 * trace_buffered_event_disable - disable buffering events
2430 *
2431 * When a filter is removed, it is faster to not use the buffered
2432 * events, and to commit directly into the ring buffer. Free up
2433 * the temp buffers when there are no more users. This requires
2434 * special synchronization with current events.
2435 */
2436void trace_buffered_event_disable(void)
2437{
2438	int cpu;
2439
2440	WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2441
2442	if (WARN_ON_ONCE(!trace_buffered_event_ref))
2443		return;
2444
2445	if (--trace_buffered_event_ref)
2446		return;
2447
2448	preempt_disable();
2449	/* For each CPU, set the buffer as used. */
2450	smp_call_function_many(tracing_buffer_mask,
2451			       disable_trace_buffered_event, NULL, 1);
2452	preempt_enable();
2453
2454	/* Wait for all current users to finish */
2455	synchronize_rcu();
2456
2457	for_each_tracing_cpu(cpu) {
2458		free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2459		per_cpu(trace_buffered_event, cpu) = NULL;
2460	}
2461	/*
2462	 * Make sure trace_buffered_event is NULL before clearing
2463	 * trace_buffered_event_cnt.
2464	 */
2465	smp_wmb();
2466
2467	preempt_disable();
2468	/* Do the work on each cpu */
2469	smp_call_function_many(tracing_buffer_mask,
2470			       enable_trace_buffered_event, NULL, 1);
2471	preempt_enable();
2472}
2473
2474static struct ring_buffer *temp_buffer;
2475
2476struct ring_buffer_event *
2477trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
2478			  struct trace_event_file *trace_file,
2479			  int type, unsigned long len,
2480			  unsigned long flags, int pc)
2481{
2482	struct ring_buffer_event *entry;
 
2483	int val;
2484
2485	*current_rb = trace_file->tr->trace_buffer.buffer;
2486
2487	if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags &
2488	     (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
2489	    (entry = this_cpu_read(trace_buffered_event))) {
2490		/* Try to use the per cpu buffer first */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2491		val = this_cpu_inc_return(trace_buffered_event_cnt);
2492		if (val == 1) {
2493			trace_event_setup(entry, type, flags, pc);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2494			entry->array[0] = len;
2495			return entry;
2496		}
2497		this_cpu_dec(trace_buffered_event_cnt);
2498	}
2499
2500	entry = __trace_buffer_lock_reserve(*current_rb,
2501					    type, len, flags, pc);
2502	/*
2503	 * If tracing is off, but we have triggers enabled
2504	 * we still need to look at the event data. Use the temp_buffer
2505	 * to store the trace event for the tigger to use. It's recusive
2506	 * safe and will not be recorded anywhere.
2507	 */
2508	if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2509		*current_rb = temp_buffer;
2510		entry = __trace_buffer_lock_reserve(*current_rb,
2511						    type, len, flags, pc);
2512	}
2513	return entry;
2514}
2515EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2516
2517static DEFINE_SPINLOCK(tracepoint_iter_lock);
2518static DEFINE_MUTEX(tracepoint_printk_mutex);
2519
2520static void output_printk(struct trace_event_buffer *fbuffer)
2521{
2522	struct trace_event_call *event_call;
 
2523	struct trace_event *event;
2524	unsigned long flags;
2525	struct trace_iterator *iter = tracepoint_print_iter;
2526
2527	/* We should never get here if iter is NULL */
2528	if (WARN_ON_ONCE(!iter))
2529		return;
2530
2531	event_call = fbuffer->trace_file->event_call;
2532	if (!event_call || !event_call->event.funcs ||
2533	    !event_call->event.funcs->trace)
2534		return;
2535
 
 
 
 
 
 
2536	event = &fbuffer->trace_file->event_call->event;
2537
2538	spin_lock_irqsave(&tracepoint_iter_lock, flags);
2539	trace_seq_init(&iter->seq);
2540	iter->ent = fbuffer->entry;
2541	event_call->event.funcs->trace(iter, 0, event);
2542	trace_seq_putc(&iter->seq, 0);
2543	printk("%s", iter->seq.buffer);
2544
2545	spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2546}
2547
2548int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2549			     void __user *buffer, size_t *lenp,
2550			     loff_t *ppos)
2551{
2552	int save_tracepoint_printk;
2553	int ret;
2554
2555	mutex_lock(&tracepoint_printk_mutex);
2556	save_tracepoint_printk = tracepoint_printk;
2557
2558	ret = proc_dointvec(table, write, buffer, lenp, ppos);
2559
2560	/*
2561	 * This will force exiting early, as tracepoint_printk
2562	 * is always zero when tracepoint_printk_iter is not allocated
2563	 */
2564	if (!tracepoint_print_iter)
2565		tracepoint_printk = 0;
2566
2567	if (save_tracepoint_printk == tracepoint_printk)
2568		goto out;
2569
2570	if (tracepoint_printk)
2571		static_key_enable(&tracepoint_printk_key.key);
2572	else
2573		static_key_disable(&tracepoint_printk_key.key);
2574
2575 out:
2576	mutex_unlock(&tracepoint_printk_mutex);
2577
2578	return ret;
2579}
2580
2581void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2582{
 
 
 
 
 
 
 
2583	if (static_key_false(&tracepoint_printk_key.key))
2584		output_printk(fbuffer);
2585
2586	event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
2587				    fbuffer->event, fbuffer->entry,
2588				    fbuffer->flags, fbuffer->pc);
 
 
 
 
 
 
 
2589}
2590EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2591
2592/*
2593 * Skip 3:
2594 *
2595 *   trace_buffer_unlock_commit_regs()
2596 *   trace_event_buffer_commit()
2597 *   trace_event_raw_event_xxx()
2598 */
2599# define STACK_SKIP 3
2600
2601void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2602				     struct ring_buffer *buffer,
2603				     struct ring_buffer_event *event,
2604				     unsigned long flags, int pc,
2605				     struct pt_regs *regs)
2606{
2607	__buffer_unlock_commit(buffer, event);
2608
2609	/*
2610	 * If regs is not set, then skip the necessary functions.
2611	 * Note, we can still get here via blktrace, wakeup tracer
2612	 * and mmiotrace, but that's ok if they lose a function or
2613	 * two. They are not that meaningful.
2614	 */
2615	ftrace_trace_stack(tr, buffer, flags, regs ? 0 : STACK_SKIP, pc, regs);
2616	ftrace_trace_userstack(buffer, flags, pc);
2617}
2618
2619/*
2620 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2621 */
2622void
2623trace_buffer_unlock_commit_nostack(struct ring_buffer *buffer,
2624				   struct ring_buffer_event *event)
2625{
2626	__buffer_unlock_commit(buffer, event);
2627}
2628
2629static void
2630trace_process_export(struct trace_export *export,
2631	       struct ring_buffer_event *event)
2632{
2633	struct trace_entry *entry;
2634	unsigned int size = 0;
2635
2636	entry = ring_buffer_event_data(event);
2637	size = ring_buffer_event_length(event);
2638	export->write(export, entry, size);
2639}
2640
2641static DEFINE_MUTEX(ftrace_export_lock);
2642
2643static struct trace_export __rcu *ftrace_exports_list __read_mostly;
2644
2645static DEFINE_STATIC_KEY_FALSE(ftrace_exports_enabled);
2646
2647static inline void ftrace_exports_enable(void)
2648{
2649	static_branch_enable(&ftrace_exports_enabled);
2650}
2651
2652static inline void ftrace_exports_disable(void)
2653{
2654	static_branch_disable(&ftrace_exports_enabled);
2655}
2656
2657static void ftrace_exports(struct ring_buffer_event *event)
2658{
2659	struct trace_export *export;
2660
2661	preempt_disable_notrace();
2662
2663	export = rcu_dereference_raw_check(ftrace_exports_list);
2664	while (export) {
2665		trace_process_export(export, event);
2666		export = rcu_dereference_raw_check(export->next);
2667	}
2668
2669	preempt_enable_notrace();
2670}
2671
2672static inline void
2673add_trace_export(struct trace_export **list, struct trace_export *export)
2674{
2675	rcu_assign_pointer(export->next, *list);
2676	/*
2677	 * We are entering export into the list but another
2678	 * CPU might be walking that list. We need to make sure
2679	 * the export->next pointer is valid before another CPU sees
2680	 * the export pointer included into the list.
2681	 */
2682	rcu_assign_pointer(*list, export);
2683}
2684
2685static inline int
2686rm_trace_export(struct trace_export **list, struct trace_export *export)
2687{
2688	struct trace_export **p;
2689
2690	for (p = list; *p != NULL; p = &(*p)->next)
2691		if (*p == export)
2692			break;
2693
2694	if (*p != export)
2695		return -1;
2696
2697	rcu_assign_pointer(*p, (*p)->next);
2698
2699	return 0;
2700}
2701
2702static inline void
2703add_ftrace_export(struct trace_export **list, struct trace_export *export)
2704{
2705	if (*list == NULL)
2706		ftrace_exports_enable();
2707
2708	add_trace_export(list, export);
2709}
2710
2711static inline int
2712rm_ftrace_export(struct trace_export **list, struct trace_export *export)
2713{
2714	int ret;
2715
2716	ret = rm_trace_export(list, export);
2717	if (*list == NULL)
2718		ftrace_exports_disable();
2719
2720	return ret;
2721}
2722
2723int register_ftrace_export(struct trace_export *export)
2724{
2725	if (WARN_ON_ONCE(!export->write))
2726		return -1;
2727
2728	mutex_lock(&ftrace_export_lock);
2729
2730	add_ftrace_export(&ftrace_exports_list, export);
2731
2732	mutex_unlock(&ftrace_export_lock);
2733
2734	return 0;
2735}
2736EXPORT_SYMBOL_GPL(register_ftrace_export);
2737
2738int unregister_ftrace_export(struct trace_export *export)
2739{
2740	int ret;
2741
2742	mutex_lock(&ftrace_export_lock);
2743
2744	ret = rm_ftrace_export(&ftrace_exports_list, export);
2745
2746	mutex_unlock(&ftrace_export_lock);
2747
2748	return ret;
2749}
2750EXPORT_SYMBOL_GPL(unregister_ftrace_export);
2751
2752void
2753trace_function(struct trace_array *tr,
2754	       unsigned long ip, unsigned long parent_ip, unsigned long flags,
2755	       int pc)
2756{
2757	struct trace_event_call *call = &event_function;
2758	struct ring_buffer *buffer = tr->trace_buffer.buffer;
2759	struct ring_buffer_event *event;
2760	struct ftrace_entry *entry;
2761
2762	event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2763					    flags, pc);
2764	if (!event)
2765		return;
2766	entry	= ring_buffer_event_data(event);
2767	entry->ip			= ip;
2768	entry->parent_ip		= parent_ip;
2769
2770	if (!call_filter_check_discard(call, entry, buffer, event)) {
2771		if (static_branch_unlikely(&ftrace_exports_enabled))
2772			ftrace_exports(event);
2773		__buffer_unlock_commit(buffer, event);
2774	}
2775}
2776
2777#ifdef CONFIG_STACKTRACE
2778
2779/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
2780#define FTRACE_KSTACK_NESTING	4
2781
2782#define FTRACE_KSTACK_ENTRIES	(PAGE_SIZE / FTRACE_KSTACK_NESTING)
2783
2784struct ftrace_stack {
2785	unsigned long		calls[FTRACE_KSTACK_ENTRIES];
2786};
2787
2788
2789struct ftrace_stacks {
2790	struct ftrace_stack	stacks[FTRACE_KSTACK_NESTING];
2791};
2792
2793static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
2794static DEFINE_PER_CPU(int, ftrace_stack_reserve);
2795
2796static void __ftrace_trace_stack(struct ring_buffer *buffer,
2797				 unsigned long flags,
2798				 int skip, int pc, struct pt_regs *regs)
2799{
2800	struct trace_event_call *call = &event_kernel_stack;
2801	struct ring_buffer_event *event;
2802	unsigned int size, nr_entries;
2803	struct ftrace_stack *fstack;
2804	struct stack_entry *entry;
2805	int stackidx;
2806
2807	/*
2808	 * Add one, for this function and the call to save_stack_trace()
2809	 * If regs is set, then these functions will not be in the way.
2810	 */
2811#ifndef CONFIG_UNWINDER_ORC
2812	if (!regs)
2813		skip++;
2814#endif
2815
2816	/*
2817	 * Since events can happen in NMIs there's no safe way to
2818	 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
2819	 * or NMI comes in, it will just have to use the default
2820	 * FTRACE_STACK_SIZE.
2821	 */
2822	preempt_disable_notrace();
2823
2824	stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
2825
2826	/* This should never happen. If it does, yell once and skip */
2827	if (WARN_ON_ONCE(stackidx > FTRACE_KSTACK_NESTING))
2828		goto out;
2829
2830	/*
2831	 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
2832	 * interrupt will either see the value pre increment or post
2833	 * increment. If the interrupt happens pre increment it will have
2834	 * restored the counter when it returns.  We just need a barrier to
2835	 * keep gcc from moving things around.
2836	 */
2837	barrier();
2838
2839	fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
2840	size = ARRAY_SIZE(fstack->calls);
2841
2842	if (regs) {
2843		nr_entries = stack_trace_save_regs(regs, fstack->calls,
2844						   size, skip);
2845	} else {
2846		nr_entries = stack_trace_save(fstack->calls, size, skip);
2847	}
2848
2849	size = nr_entries * sizeof(unsigned long);
2850	event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
2851					    sizeof(*entry) + size, flags, pc);
 
2852	if (!event)
2853		goto out;
2854	entry = ring_buffer_event_data(event);
2855
2856	memcpy(&entry->caller, fstack->calls, size);
2857	entry->size = nr_entries;
2858
2859	if (!call_filter_check_discard(call, entry, buffer, event))
2860		__buffer_unlock_commit(buffer, event);
2861
2862 out:
2863	/* Again, don't let gcc optimize things here */
2864	barrier();
2865	__this_cpu_dec(ftrace_stack_reserve);
2866	preempt_enable_notrace();
2867
2868}
2869
2870static inline void ftrace_trace_stack(struct trace_array *tr,
2871				      struct ring_buffer *buffer,
2872				      unsigned long flags,
2873				      int skip, int pc, struct pt_regs *regs)
2874{
2875	if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
2876		return;
2877
2878	__ftrace_trace_stack(buffer, flags, skip, pc, regs);
2879}
2880
2881void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
2882		   int pc)
2883{
2884	struct ring_buffer *buffer = tr->trace_buffer.buffer;
2885
2886	if (rcu_is_watching()) {
2887		__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
2888		return;
2889	}
2890
2891	/*
2892	 * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
2893	 * but if the above rcu_is_watching() failed, then the NMI
2894	 * triggered someplace critical, and rcu_irq_enter() should
2895	 * not be called from NMI.
2896	 */
2897	if (unlikely(in_nmi()))
2898		return;
2899
2900	rcu_irq_enter_irqson();
2901	__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
2902	rcu_irq_exit_irqson();
2903}
2904
2905/**
2906 * trace_dump_stack - record a stack back trace in the trace buffer
2907 * @skip: Number of functions to skip (helper handlers)
2908 */
2909void trace_dump_stack(int skip)
2910{
2911	unsigned long flags;
2912
2913	if (tracing_disabled || tracing_selftest_running)
2914		return;
2915
2916	local_save_flags(flags);
2917
2918#ifndef CONFIG_UNWINDER_ORC
2919	/* Skip 1 to skip this function. */
2920	skip++;
2921#endif
2922	__ftrace_trace_stack(global_trace.trace_buffer.buffer,
2923			     flags, skip, preempt_count(), NULL);
2924}
2925EXPORT_SYMBOL_GPL(trace_dump_stack);
2926
2927#ifdef CONFIG_USER_STACKTRACE_SUPPORT
2928static DEFINE_PER_CPU(int, user_stack_count);
2929
2930static void
2931ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 
2932{
2933	struct trace_event_call *call = &event_user_stack;
2934	struct ring_buffer_event *event;
2935	struct userstack_entry *entry;
2936
2937	if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE))
2938		return;
2939
2940	/*
2941	 * NMIs can not handle page faults, even with fix ups.
2942	 * The save user stack can (and often does) fault.
2943	 */
2944	if (unlikely(in_nmi()))
2945		return;
2946
2947	/*
2948	 * prevent recursion, since the user stack tracing may
2949	 * trigger other kernel events.
2950	 */
2951	preempt_disable();
2952	if (__this_cpu_read(user_stack_count))
2953		goto out;
2954
2955	__this_cpu_inc(user_stack_count);
2956
2957	event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
2958					    sizeof(*entry), flags, pc);
2959	if (!event)
2960		goto out_drop_count;
2961	entry	= ring_buffer_event_data(event);
2962
2963	entry->tgid		= current->tgid;
2964	memset(&entry->caller, 0, sizeof(entry->caller));
2965
2966	stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
2967	if (!call_filter_check_discard(call, entry, buffer, event))
2968		__buffer_unlock_commit(buffer, event);
2969
2970 out_drop_count:
2971	__this_cpu_dec(user_stack_count);
2972 out:
2973	preempt_enable();
2974}
2975#else /* CONFIG_USER_STACKTRACE_SUPPORT */
2976static void ftrace_trace_userstack(struct ring_buffer *buffer,
2977				   unsigned long flags, int pc)
 
2978{
2979}
2980#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
2981
2982#endif /* CONFIG_STACKTRACE */
2983
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2984/* created for use with alloc_percpu */
2985struct trace_buffer_struct {
2986	int nesting;
2987	char buffer[4][TRACE_BUF_SIZE];
2988};
2989
2990static struct trace_buffer_struct *trace_percpu_buffer;
2991
2992/*
2993 * Thise allows for lockless recording.  If we're nested too deeply, then
2994 * this returns NULL.
2995 */
2996static char *get_trace_buf(void)
2997{
2998	struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
2999
3000	if (!buffer || buffer->nesting >= 4)
3001		return NULL;
3002
3003	buffer->nesting++;
3004
3005	/* Interrupts must see nesting incremented before we use the buffer */
3006	barrier();
3007	return &buffer->buffer[buffer->nesting][0];
3008}
3009
3010static void put_trace_buf(void)
3011{
3012	/* Don't let the decrement of nesting leak before this */
3013	barrier();
3014	this_cpu_dec(trace_percpu_buffer->nesting);
3015}
3016
3017static int alloc_percpu_trace_buffer(void)
3018{
3019	struct trace_buffer_struct *buffers;
3020
 
 
 
3021	buffers = alloc_percpu(struct trace_buffer_struct);
3022	if (WARN(!buffers, "Could not allocate percpu trace_printk buffer"))
3023		return -ENOMEM;
3024
3025	trace_percpu_buffer = buffers;
3026	return 0;
3027}
3028
3029static int buffers_allocated;
3030
3031void trace_printk_init_buffers(void)
3032{
3033	if (buffers_allocated)
3034		return;
3035
3036	if (alloc_percpu_trace_buffer())
3037		return;
3038
3039	/* trace_printk() is for debug use only. Don't use it in production. */
3040
3041	pr_warn("\n");
3042	pr_warn("**********************************************************\n");
3043	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
3044	pr_warn("**                                                      **\n");
3045	pr_warn("** trace_printk() being used. Allocating extra memory.  **\n");
3046	pr_warn("**                                                      **\n");
3047	pr_warn("** This means that this is a DEBUG kernel and it is     **\n");
3048	pr_warn("** unsafe for production use.                           **\n");
3049	pr_warn("**                                                      **\n");
3050	pr_warn("** If you see this message and you are not debugging    **\n");
3051	pr_warn("** the kernel, report this immediately to your vendor!  **\n");
3052	pr_warn("**                                                      **\n");
3053	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
3054	pr_warn("**********************************************************\n");
3055
3056	/* Expand the buffers to set size */
3057	tracing_update_buffers();
3058
3059	buffers_allocated = 1;
3060
3061	/*
3062	 * trace_printk_init_buffers() can be called by modules.
3063	 * If that happens, then we need to start cmdline recording
3064	 * directly here. If the global_trace.buffer is already
3065	 * allocated here, then this was called by module code.
3066	 */
3067	if (global_trace.trace_buffer.buffer)
3068		tracing_start_cmdline_record();
3069}
3070EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3071
3072void trace_printk_start_comm(void)
3073{
3074	/* Start tracing comms if trace printk is set */
3075	if (!buffers_allocated)
3076		return;
3077	tracing_start_cmdline_record();
3078}
3079
3080static void trace_printk_start_stop_comm(int enabled)
3081{
3082	if (!buffers_allocated)
3083		return;
3084
3085	if (enabled)
3086		tracing_start_cmdline_record();
3087	else
3088		tracing_stop_cmdline_record();
3089}
3090
3091/**
3092 * trace_vbprintk - write binary msg to tracing buffer
3093 * @ip:    The address of the caller
3094 * @fmt:   The string format to write to the buffer
3095 * @args:  Arguments for @fmt
3096 */
3097int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3098{
3099	struct trace_event_call *call = &event_bprint;
3100	struct ring_buffer_event *event;
3101	struct ring_buffer *buffer;
3102	struct trace_array *tr = &global_trace;
3103	struct bprint_entry *entry;
3104	unsigned long flags;
3105	char *tbuffer;
3106	int len = 0, size, pc;
3107
3108	if (unlikely(tracing_selftest_running || tracing_disabled))
3109		return 0;
3110
3111	/* Don't pollute graph traces with trace_vprintk internals */
3112	pause_graph_tracing();
3113
3114	pc = preempt_count();
3115	preempt_disable_notrace();
3116
3117	tbuffer = get_trace_buf();
3118	if (!tbuffer) {
3119		len = 0;
3120		goto out_nobuffer;
3121	}
3122
3123	len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3124
3125	if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3126		goto out;
3127
3128	local_save_flags(flags);
3129	size = sizeof(*entry) + sizeof(u32) * len;
3130	buffer = tr->trace_buffer.buffer;
 
3131	event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3132					    flags, pc);
3133	if (!event)
3134		goto out;
3135	entry = ring_buffer_event_data(event);
3136	entry->ip			= ip;
3137	entry->fmt			= fmt;
3138
3139	memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3140	if (!call_filter_check_discard(call, entry, buffer, event)) {
3141		__buffer_unlock_commit(buffer, event);
3142		ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
3143	}
3144
3145out:
 
 
3146	put_trace_buf();
3147
3148out_nobuffer:
3149	preempt_enable_notrace();
3150	unpause_graph_tracing();
3151
3152	return len;
3153}
3154EXPORT_SYMBOL_GPL(trace_vbprintk);
3155
3156__printf(3, 0)
3157static int
3158__trace_array_vprintk(struct ring_buffer *buffer,
3159		      unsigned long ip, const char *fmt, va_list args)
3160{
3161	struct trace_event_call *call = &event_print;
3162	struct ring_buffer_event *event;
3163	int len = 0, size, pc;
3164	struct print_entry *entry;
3165	unsigned long flags;
3166	char *tbuffer;
3167
3168	if (tracing_disabled || tracing_selftest_running)
3169		return 0;
3170
3171	/* Don't pollute graph traces with trace_vprintk internals */
3172	pause_graph_tracing();
3173
3174	pc = preempt_count();
3175	preempt_disable_notrace();
3176
3177
3178	tbuffer = get_trace_buf();
3179	if (!tbuffer) {
3180		len = 0;
3181		goto out_nobuffer;
3182	}
3183
3184	len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3185
3186	local_save_flags(flags);
3187	size = sizeof(*entry) + len + 1;
 
3188	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3189					    flags, pc);
3190	if (!event)
3191		goto out;
3192	entry = ring_buffer_event_data(event);
3193	entry->ip = ip;
3194
3195	memcpy(&entry->buf, tbuffer, len + 1);
3196	if (!call_filter_check_discard(call, entry, buffer, event)) {
3197		__buffer_unlock_commit(buffer, event);
3198		ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
3199	}
3200
3201out:
 
3202	put_trace_buf();
3203
3204out_nobuffer:
3205	preempt_enable_notrace();
3206	unpause_graph_tracing();
3207
3208	return len;
3209}
3210
3211__printf(3, 0)
3212int trace_array_vprintk(struct trace_array *tr,
3213			unsigned long ip, const char *fmt, va_list args)
3214{
3215	return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
3216}
3217
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3218__printf(3, 0)
3219int trace_array_printk(struct trace_array *tr,
3220		       unsigned long ip, const char *fmt, ...)
3221{
3222	int ret;
3223	va_list ap;
3224
3225	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
 
 
 
 
 
 
 
3226		return 0;
3227
3228	va_start(ap, fmt);
3229	ret = trace_array_vprintk(tr, ip, fmt, ap);
3230	va_end(ap);
3231	return ret;
3232}
3233EXPORT_SYMBOL_GPL(trace_array_printk);
3234
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3235__printf(3, 4)
3236int trace_array_printk_buf(struct ring_buffer *buffer,
3237			   unsigned long ip, const char *fmt, ...)
3238{
3239	int ret;
3240	va_list ap;
3241
3242	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3243		return 0;
3244
3245	va_start(ap, fmt);
3246	ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3247	va_end(ap);
3248	return ret;
3249}
3250
3251__printf(2, 0)
3252int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3253{
3254	return trace_array_vprintk(&global_trace, ip, fmt, args);
3255}
3256EXPORT_SYMBOL_GPL(trace_vprintk);
3257
3258static void trace_iterator_increment(struct trace_iterator *iter)
3259{
3260	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3261
3262	iter->idx++;
3263	if (buf_iter)
3264		ring_buffer_read(buf_iter, NULL);
3265}
3266
3267static struct trace_entry *
3268peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3269		unsigned long *lost_events)
3270{
3271	struct ring_buffer_event *event;
3272	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3273
3274	if (buf_iter)
3275		event = ring_buffer_iter_peek(buf_iter, ts);
3276	else
3277		event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
 
 
 
3278					 lost_events);
 
3279
3280	if (event) {
3281		iter->ent_size = ring_buffer_event_length(event);
3282		return ring_buffer_event_data(event);
3283	}
3284	iter->ent_size = 0;
3285	return NULL;
3286}
3287
3288static struct trace_entry *
3289__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3290		  unsigned long *missing_events, u64 *ent_ts)
3291{
3292	struct ring_buffer *buffer = iter->trace_buffer->buffer;
3293	struct trace_entry *ent, *next = NULL;
3294	unsigned long lost_events = 0, next_lost = 0;
3295	int cpu_file = iter->cpu_file;
3296	u64 next_ts = 0, ts;
3297	int next_cpu = -1;
3298	int next_size = 0;
3299	int cpu;
3300
3301	/*
3302	 * If we are in a per_cpu trace file, don't bother by iterating over
3303	 * all cpu and peek directly.
3304	 */
3305	if (cpu_file > RING_BUFFER_ALL_CPUS) {
3306		if (ring_buffer_empty_cpu(buffer, cpu_file))
3307			return NULL;
3308		ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3309		if (ent_cpu)
3310			*ent_cpu = cpu_file;
3311
3312		return ent;
3313	}
3314
3315	for_each_tracing_cpu(cpu) {
3316
3317		if (ring_buffer_empty_cpu(buffer, cpu))
3318			continue;
3319
3320		ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3321
3322		/*
3323		 * Pick the entry with the smallest timestamp:
3324		 */
3325		if (ent && (!next || ts < next_ts)) {
3326			next = ent;
3327			next_cpu = cpu;
3328			next_ts = ts;
3329			next_lost = lost_events;
3330			next_size = iter->ent_size;
3331		}
3332	}
3333
3334	iter->ent_size = next_size;
3335
3336	if (ent_cpu)
3337		*ent_cpu = next_cpu;
3338
3339	if (ent_ts)
3340		*ent_ts = next_ts;
3341
3342	if (missing_events)
3343		*missing_events = next_lost;
3344
3345	return next;
3346}
3347
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3348/* Find the next real entry, without updating the iterator itself */
3349struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
3350					  int *ent_cpu, u64 *ent_ts)
3351{
3352	return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3353}
3354
3355/* Find the next real entry, and increment the iterator to the next entry */
3356void *trace_find_next_entry_inc(struct trace_iterator *iter)
3357{
3358	iter->ent = __find_next_entry(iter, &iter->cpu,
3359				      &iter->lost_events, &iter->ts);
3360
3361	if (iter->ent)
3362		trace_iterator_increment(iter);
3363
3364	return iter->ent ? iter : NULL;
3365}
3366
3367static void trace_consume(struct trace_iterator *iter)
3368{
3369	ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
3370			    &iter->lost_events);
3371}
3372
3373static void *s_next(struct seq_file *m, void *v, loff_t *pos)
3374{
3375	struct trace_iterator *iter = m->private;
3376	int i = (int)*pos;
3377	void *ent;
3378
3379	WARN_ON_ONCE(iter->leftover);
3380
3381	(*pos)++;
3382
3383	/* can't go backwards */
3384	if (iter->idx > i)
3385		return NULL;
3386
3387	if (iter->idx < 0)
3388		ent = trace_find_next_entry_inc(iter);
3389	else
3390		ent = iter;
3391
3392	while (ent && iter->idx < i)
3393		ent = trace_find_next_entry_inc(iter);
3394
3395	iter->pos = *pos;
3396
3397	return ent;
3398}
3399
3400void tracing_iter_reset(struct trace_iterator *iter, int cpu)
3401{
3402	struct ring_buffer_event *event;
3403	struct ring_buffer_iter *buf_iter;
3404	unsigned long entries = 0;
3405	u64 ts;
3406
3407	per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
3408
3409	buf_iter = trace_buffer_iter(iter, cpu);
3410	if (!buf_iter)
3411		return;
3412
3413	ring_buffer_iter_reset(buf_iter);
3414
3415	/*
3416	 * We could have the case with the max latency tracers
3417	 * that a reset never took place on a cpu. This is evident
3418	 * by the timestamp being before the start of the buffer.
3419	 */
3420	while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
3421		if (ts >= iter->trace_buffer->time_start)
3422			break;
3423		entries++;
3424		ring_buffer_read(buf_iter, NULL);
3425	}
3426
3427	per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
3428}
3429
3430/*
3431 * The current tracer is copied to avoid a global locking
3432 * all around.
3433 */
3434static void *s_start(struct seq_file *m, loff_t *pos)
3435{
3436	struct trace_iterator *iter = m->private;
3437	struct trace_array *tr = iter->tr;
3438	int cpu_file = iter->cpu_file;
3439	void *p = NULL;
3440	loff_t l = 0;
3441	int cpu;
3442
3443	/*
3444	 * copy the tracer to avoid using a global lock all around.
3445	 * iter->trace is a copy of current_trace, the pointer to the
3446	 * name may be used instead of a strcmp(), as iter->trace->name
3447	 * will point to the same string as current_trace->name.
3448	 */
3449	mutex_lock(&trace_types_lock);
3450	if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
3451		*iter->trace = *tr->current_trace;
3452	mutex_unlock(&trace_types_lock);
3453
3454#ifdef CONFIG_TRACER_MAX_TRACE
3455	if (iter->snapshot && iter->trace->use_max_tr)
3456		return ERR_PTR(-EBUSY);
3457#endif
3458
3459	if (!iter->snapshot)
3460		atomic_inc(&trace_record_taskinfo_disabled);
3461
3462	if (*pos != iter->pos) {
3463		iter->ent = NULL;
3464		iter->cpu = 0;
3465		iter->idx = -1;
3466
3467		if (cpu_file == RING_BUFFER_ALL_CPUS) {
3468			for_each_tracing_cpu(cpu)
3469				tracing_iter_reset(iter, cpu);
3470		} else
3471			tracing_iter_reset(iter, cpu_file);
3472
3473		iter->leftover = 0;
3474		for (p = iter; p && l < *pos; p = s_next(m, p, &l))
3475			;
3476
3477	} else {
3478		/*
3479		 * If we overflowed the seq_file before, then we want
3480		 * to just reuse the trace_seq buffer again.
3481		 */
3482		if (iter->leftover)
3483			p = iter;
3484		else {
3485			l = *pos - 1;
3486			p = s_next(m, p, &l);
3487		}
3488	}
3489
3490	trace_event_read_lock();
3491	trace_access_lock(cpu_file);
3492	return p;
3493}
3494
3495static void s_stop(struct seq_file *m, void *p)
3496{
3497	struct trace_iterator *iter = m->private;
3498
3499#ifdef CONFIG_TRACER_MAX_TRACE
3500	if (iter->snapshot && iter->trace->use_max_tr)
3501		return;
3502#endif
3503
3504	if (!iter->snapshot)
3505		atomic_dec(&trace_record_taskinfo_disabled);
3506
3507	trace_access_unlock(iter->cpu_file);
3508	trace_event_read_unlock();
3509}
3510
3511static void
3512get_total_entries_cpu(struct trace_buffer *buf, unsigned long *total,
3513		      unsigned long *entries, int cpu)
3514{
3515	unsigned long count;
3516
3517	count = ring_buffer_entries_cpu(buf->buffer, cpu);
3518	/*
3519	 * If this buffer has skipped entries, then we hold all
3520	 * entries for the trace and we need to ignore the
3521	 * ones before the time stamp.
3522	 */
3523	if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
3524		count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
3525		/* total is the same as the entries */
3526		*total = count;
3527	} else
3528		*total = count +
3529			ring_buffer_overrun_cpu(buf->buffer, cpu);
3530	*entries = count;
3531}
3532
3533static void
3534get_total_entries(struct trace_buffer *buf,
3535		  unsigned long *total, unsigned long *entries)
3536{
3537	unsigned long t, e;
3538	int cpu;
3539
3540	*total = 0;
3541	*entries = 0;
3542
3543	for_each_tracing_cpu(cpu) {
3544		get_total_entries_cpu(buf, &t, &e, cpu);
3545		*total += t;
3546		*entries += e;
3547	}
3548}
3549
3550unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
3551{
3552	unsigned long total, entries;
3553
3554	if (!tr)
3555		tr = &global_trace;
3556
3557	get_total_entries_cpu(&tr->trace_buffer, &total, &entries, cpu);
3558
3559	return entries;
3560}
3561
3562unsigned long trace_total_entries(struct trace_array *tr)
3563{
3564	unsigned long total, entries;
3565
3566	if (!tr)
3567		tr = &global_trace;
3568
3569	get_total_entries(&tr->trace_buffer, &total, &entries);
3570
3571	return entries;
3572}
3573
3574static void print_lat_help_header(struct seq_file *m)
3575{
3576	seq_puts(m, "#                  _------=> CPU#            \n"
3577		    "#                 / _-----=> irqs-off        \n"
3578		    "#                | / _----=> need-resched    \n"
3579		    "#                || / _---=> hardirq/softirq \n"
3580		    "#                ||| / _--=> preempt-depth   \n"
3581		    "#                |||| /     delay            \n"
3582		    "#  cmd     pid   ||||| time  |   caller      \n"
3583		    "#     \\   /      |||||  \\    |   /         \n");
3584}
3585
3586static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
3587{
3588	unsigned long total;
3589	unsigned long entries;
3590
3591	get_total_entries(buf, &total, &entries);
3592	seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu   #P:%d\n",
3593		   entries, total, num_online_cpus());
3594	seq_puts(m, "#\n");
3595}
3596
3597static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m,
3598				   unsigned int flags)
3599{
3600	bool tgid = flags & TRACE_ITER_RECORD_TGID;
3601
3602	print_event_info(buf, m);
3603
3604	seq_printf(m, "#           TASK-PID   %s  CPU#   TIMESTAMP  FUNCTION\n", tgid ? "TGID     " : "");
3605	seq_printf(m, "#              | |     %s    |       |         |\n",	 tgid ? "  |      " : "");
3606}
3607
3608static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m,
3609				       unsigned int flags)
3610{
3611	bool tgid = flags & TRACE_ITER_RECORD_TGID;
3612	const char *space = "          ";
3613	int prec = tgid ? 10 : 2;
3614
3615	print_event_info(buf, m);
3616
3617	seq_printf(m, "#                          %.*s  _-----=> irqs-off\n", prec, space);
3618	seq_printf(m, "#                          %.*s / _----=> need-resched\n", prec, space);
3619	seq_printf(m, "#                          %.*s| / _---=> hardirq/softirq\n", prec, space);
3620	seq_printf(m, "#                          %.*s|| / _--=> preempt-depth\n", prec, space);
3621	seq_printf(m, "#                          %.*s||| /     delay\n", prec, space);
3622	seq_printf(m, "#           TASK-PID %.*sCPU#  ||||    TIMESTAMP  FUNCTION\n", prec, "   TGID   ");
3623	seq_printf(m, "#              | |   %.*s  |   ||||       |         |\n", prec, "     |    ");
3624}
3625
3626void
3627print_trace_header(struct seq_file *m, struct trace_iterator *iter)
3628{
3629	unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
3630	struct trace_buffer *buf = iter->trace_buffer;
3631	struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
3632	struct tracer *type = iter->trace;
3633	unsigned long entries;
3634	unsigned long total;
3635	const char *name = "preemption";
3636
3637	name = type->name;
3638
3639	get_total_entries(buf, &total, &entries);
3640
3641	seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
3642		   name, UTS_RELEASE);
3643	seq_puts(m, "# -----------------------------------"
3644		 "---------------------------------\n");
3645	seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
3646		   " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
3647		   nsecs_to_usecs(data->saved_latency),
3648		   entries,
3649		   total,
3650		   buf->cpu,
3651#if defined(CONFIG_PREEMPT_NONE)
3652		   "server",
3653#elif defined(CONFIG_PREEMPT_VOLUNTARY)
3654		   "desktop",
3655#elif defined(CONFIG_PREEMPT)
3656		   "preempt",
 
 
3657#else
3658		   "unknown",
3659#endif
3660		   /* These are reserved for later use */
3661		   0, 0, 0, 0);
3662#ifdef CONFIG_SMP
3663	seq_printf(m, " #P:%d)\n", num_online_cpus());
3664#else
3665	seq_puts(m, ")\n");
3666#endif
3667	seq_puts(m, "#    -----------------\n");
3668	seq_printf(m, "#    | task: %.16s-%d "
3669		   "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
3670		   data->comm, data->pid,
3671		   from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
3672		   data->policy, data->rt_priority);
3673	seq_puts(m, "#    -----------------\n");
3674
3675	if (data->critical_start) {
3676		seq_puts(m, "#  => started at: ");
3677		seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
3678		trace_print_seq(m, &iter->seq);
3679		seq_puts(m, "\n#  => ended at:   ");
3680		seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
3681		trace_print_seq(m, &iter->seq);
3682		seq_puts(m, "\n#\n");
3683	}
3684
3685	seq_puts(m, "#\n");
3686}
3687
3688static void test_cpu_buff_start(struct trace_iterator *iter)
3689{
3690	struct trace_seq *s = &iter->seq;
3691	struct trace_array *tr = iter->tr;
3692
3693	if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
3694		return;
3695
3696	if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
3697		return;
3698
3699	if (cpumask_available(iter->started) &&
3700	    cpumask_test_cpu(iter->cpu, iter->started))
3701		return;
3702
3703	if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
3704		return;
3705
3706	if (cpumask_available(iter->started))
3707		cpumask_set_cpu(iter->cpu, iter->started);
3708
3709	/* Don't print started cpu buffer for the first entry of the trace */
3710	if (iter->idx > 1)
3711		trace_seq_printf(s, "##### CPU %u buffer started ####\n",
3712				iter->cpu);
3713}
3714
3715static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
3716{
3717	struct trace_array *tr = iter->tr;
3718	struct trace_seq *s = &iter->seq;
3719	unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
3720	struct trace_entry *entry;
3721	struct trace_event *event;
3722
3723	entry = iter->ent;
3724
3725	test_cpu_buff_start(iter);
3726
3727	event = ftrace_find_event(entry->type);
3728
3729	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3730		if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3731			trace_print_lat_context(iter);
3732		else
3733			trace_print_context(iter);
3734	}
3735
3736	if (trace_seq_has_overflowed(s))
3737		return TRACE_TYPE_PARTIAL_LINE;
3738
3739	if (event)
3740		return event->funcs->trace(iter, sym_flags, event);
3741
3742	trace_seq_printf(s, "Unknown type %d\n", entry->type);
3743
3744	return trace_handle_return(s);
3745}
3746
3747static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
3748{
3749	struct trace_array *tr = iter->tr;
3750	struct trace_seq *s = &iter->seq;
3751	struct trace_entry *entry;
3752	struct trace_event *event;
3753
3754	entry = iter->ent;
3755
3756	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
3757		trace_seq_printf(s, "%d %d %llu ",
3758				 entry->pid, iter->cpu, iter->ts);
3759
3760	if (trace_seq_has_overflowed(s))
3761		return TRACE_TYPE_PARTIAL_LINE;
3762
3763	event = ftrace_find_event(entry->type);
3764	if (event)
3765		return event->funcs->raw(iter, 0, event);
3766
3767	trace_seq_printf(s, "%d ?\n", entry->type);
3768
3769	return trace_handle_return(s);
3770}
3771
3772static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
3773{
3774	struct trace_array *tr = iter->tr;
3775	struct trace_seq *s = &iter->seq;
3776	unsigned char newline = '\n';
3777	struct trace_entry *entry;
3778	struct trace_event *event;
3779
3780	entry = iter->ent;
3781
3782	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3783		SEQ_PUT_HEX_FIELD(s, entry->pid);
3784		SEQ_PUT_HEX_FIELD(s, iter->cpu);
3785		SEQ_PUT_HEX_FIELD(s, iter->ts);
3786		if (trace_seq_has_overflowed(s))
3787			return TRACE_TYPE_PARTIAL_LINE;
3788	}
3789
3790	event = ftrace_find_event(entry->type);
3791	if (event) {
3792		enum print_line_t ret = event->funcs->hex(iter, 0, event);
3793		if (ret != TRACE_TYPE_HANDLED)
3794			return ret;
3795	}
3796
3797	SEQ_PUT_FIELD(s, newline);
3798
3799	return trace_handle_return(s);
3800}
3801
3802static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
3803{
3804	struct trace_array *tr = iter->tr;
3805	struct trace_seq *s = &iter->seq;
3806	struct trace_entry *entry;
3807	struct trace_event *event;
3808
3809	entry = iter->ent;
3810
3811	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
3812		SEQ_PUT_FIELD(s, entry->pid);
3813		SEQ_PUT_FIELD(s, iter->cpu);
3814		SEQ_PUT_FIELD(s, iter->ts);
3815		if (trace_seq_has_overflowed(s))
3816			return TRACE_TYPE_PARTIAL_LINE;
3817	}
3818
3819	event = ftrace_find_event(entry->type);
3820	return event ? event->funcs->binary(iter, 0, event) :
3821		TRACE_TYPE_HANDLED;
3822}
3823
3824int trace_empty(struct trace_iterator *iter)
3825{
3826	struct ring_buffer_iter *buf_iter;
3827	int cpu;
3828
3829	/* If we are looking at one CPU buffer, only check that one */
3830	if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
3831		cpu = iter->cpu_file;
3832		buf_iter = trace_buffer_iter(iter, cpu);
3833		if (buf_iter) {
3834			if (!ring_buffer_iter_empty(buf_iter))
3835				return 0;
3836		} else {
3837			if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3838				return 0;
3839		}
3840		return 1;
3841	}
3842
3843	for_each_tracing_cpu(cpu) {
3844		buf_iter = trace_buffer_iter(iter, cpu);
3845		if (buf_iter) {
3846			if (!ring_buffer_iter_empty(buf_iter))
3847				return 0;
3848		} else {
3849			if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
3850				return 0;
3851		}
3852	}
3853
3854	return 1;
3855}
3856
3857/*  Called with trace_event_read_lock() held. */
3858enum print_line_t print_trace_line(struct trace_iterator *iter)
3859{
3860	struct trace_array *tr = iter->tr;
3861	unsigned long trace_flags = tr->trace_flags;
3862	enum print_line_t ret;
3863
3864	if (iter->lost_events) {
3865		trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
3866				 iter->cpu, iter->lost_events);
 
 
 
 
3867		if (trace_seq_has_overflowed(&iter->seq))
3868			return TRACE_TYPE_PARTIAL_LINE;
3869	}
3870
3871	if (iter->trace && iter->trace->print_line) {
3872		ret = iter->trace->print_line(iter);
3873		if (ret != TRACE_TYPE_UNHANDLED)
3874			return ret;
3875	}
3876
3877	if (iter->ent->type == TRACE_BPUTS &&
3878			trace_flags & TRACE_ITER_PRINTK &&
3879			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3880		return trace_print_bputs_msg_only(iter);
3881
3882	if (iter->ent->type == TRACE_BPRINT &&
3883			trace_flags & TRACE_ITER_PRINTK &&
3884			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3885		return trace_print_bprintk_msg_only(iter);
3886
3887	if (iter->ent->type == TRACE_PRINT &&
3888			trace_flags & TRACE_ITER_PRINTK &&
3889			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
3890		return trace_print_printk_msg_only(iter);
3891
3892	if (trace_flags & TRACE_ITER_BIN)
3893		return print_bin_fmt(iter);
3894
3895	if (trace_flags & TRACE_ITER_HEX)
3896		return print_hex_fmt(iter);
3897
3898	if (trace_flags & TRACE_ITER_RAW)
3899		return print_raw_fmt(iter);
3900
3901	return print_trace_fmt(iter);
3902}
3903
3904void trace_latency_header(struct seq_file *m)
3905{
3906	struct trace_iterator *iter = m->private;
3907	struct trace_array *tr = iter->tr;
3908
3909	/* print nothing if the buffers are empty */
3910	if (trace_empty(iter))
3911		return;
3912
3913	if (iter->iter_flags & TRACE_FILE_LAT_FMT)
3914		print_trace_header(m, iter);
3915
3916	if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
3917		print_lat_help_header(m);
3918}
3919
3920void trace_default_header(struct seq_file *m)
3921{
3922	struct trace_iterator *iter = m->private;
3923	struct trace_array *tr = iter->tr;
3924	unsigned long trace_flags = tr->trace_flags;
3925
3926	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
3927		return;
3928
3929	if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
3930		/* print nothing if the buffers are empty */
3931		if (trace_empty(iter))
3932			return;
3933		print_trace_header(m, iter);
3934		if (!(trace_flags & TRACE_ITER_VERBOSE))
3935			print_lat_help_header(m);
3936	} else {
3937		if (!(trace_flags & TRACE_ITER_VERBOSE)) {
3938			if (trace_flags & TRACE_ITER_IRQ_INFO)
3939				print_func_help_header_irq(iter->trace_buffer,
3940							   m, trace_flags);
3941			else
3942				print_func_help_header(iter->trace_buffer, m,
3943						       trace_flags);
3944		}
3945	}
3946}
3947
3948static void test_ftrace_alive(struct seq_file *m)
3949{
3950	if (!ftrace_is_dead())
3951		return;
3952	seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
3953		    "#          MAY BE MISSING FUNCTION EVENTS\n");
3954}
3955
3956#ifdef CONFIG_TRACER_MAX_TRACE
3957static void show_snapshot_main_help(struct seq_file *m)
3958{
3959	seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
3960		    "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3961		    "#                      Takes a snapshot of the main buffer.\n"
3962		    "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
3963		    "#                      (Doesn't have to be '2' works with any number that\n"
3964		    "#                       is not a '0' or '1')\n");
3965}
3966
3967static void show_snapshot_percpu_help(struct seq_file *m)
3968{
3969	seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
3970#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
3971	seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
3972		    "#                      Takes a snapshot of the main buffer for this cpu.\n");
3973#else
3974	seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
3975		    "#                     Must use main snapshot file to allocate.\n");
3976#endif
3977	seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
3978		    "#                      (Doesn't have to be '2' works with any number that\n"
3979		    "#                       is not a '0' or '1')\n");
3980}
3981
3982static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
3983{
3984	if (iter->tr->allocated_snapshot)
3985		seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
3986	else
3987		seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
3988
3989	seq_puts(m, "# Snapshot commands:\n");
3990	if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
3991		show_snapshot_main_help(m);
3992	else
3993		show_snapshot_percpu_help(m);
3994}
3995#else
3996/* Should never be called */
3997static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
3998#endif
3999
4000static int s_show(struct seq_file *m, void *v)
4001{
4002	struct trace_iterator *iter = v;
4003	int ret;
4004
4005	if (iter->ent == NULL) {
4006		if (iter->tr) {
4007			seq_printf(m, "# tracer: %s\n", iter->trace->name);
4008			seq_puts(m, "#\n");
4009			test_ftrace_alive(m);
4010		}
4011		if (iter->snapshot && trace_empty(iter))
4012			print_snapshot_help(m, iter);
4013		else if (iter->trace && iter->trace->print_header)
4014			iter->trace->print_header(m);
4015		else
4016			trace_default_header(m);
4017
4018	} else if (iter->leftover) {
4019		/*
4020		 * If we filled the seq_file buffer earlier, we
4021		 * want to just show it now.
4022		 */
4023		ret = trace_print_seq(m, &iter->seq);
4024
4025		/* ret should this time be zero, but you never know */
4026		iter->leftover = ret;
4027
4028	} else {
4029		print_trace_line(iter);
4030		ret = trace_print_seq(m, &iter->seq);
4031		/*
4032		 * If we overflow the seq_file buffer, then it will
4033		 * ask us for this data again at start up.
4034		 * Use that instead.
4035		 *  ret is 0 if seq_file write succeeded.
4036		 *        -1 otherwise.
4037		 */
4038		iter->leftover = ret;
4039	}
4040
4041	return 0;
4042}
4043
4044/*
4045 * Should be used after trace_array_get(), trace_types_lock
4046 * ensures that i_cdev was already initialized.
4047 */
4048static inline int tracing_get_cpu(struct inode *inode)
4049{
4050	if (inode->i_cdev) /* See trace_create_cpu_file() */
4051		return (long)inode->i_cdev - 1;
4052	return RING_BUFFER_ALL_CPUS;
4053}
4054
4055static const struct seq_operations tracer_seq_ops = {
4056	.start		= s_start,
4057	.next		= s_next,
4058	.stop		= s_stop,
4059	.show		= s_show,
4060};
4061
4062static struct trace_iterator *
4063__tracing_open(struct inode *inode, struct file *file, bool snapshot)
4064{
4065	struct trace_array *tr = inode->i_private;
4066	struct trace_iterator *iter;
4067	int cpu;
4068
4069	if (tracing_disabled)
4070		return ERR_PTR(-ENODEV);
4071
4072	iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4073	if (!iter)
4074		return ERR_PTR(-ENOMEM);
4075
4076	iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4077				    GFP_KERNEL);
4078	if (!iter->buffer_iter)
4079		goto release;
4080
4081	/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4082	 * We make a copy of the current tracer to avoid concurrent
4083	 * changes on it while we are reading.
4084	 */
4085	mutex_lock(&trace_types_lock);
4086	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
4087	if (!iter->trace)
4088		goto fail;
4089
4090	*iter->trace = *tr->current_trace;
4091
4092	if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4093		goto fail;
4094
4095	iter->tr = tr;
4096
4097#ifdef CONFIG_TRACER_MAX_TRACE
4098	/* Currently only the top directory has a snapshot */
4099	if (tr->current_trace->print_max || snapshot)
4100		iter->trace_buffer = &tr->max_buffer;
4101	else
4102#endif
4103		iter->trace_buffer = &tr->trace_buffer;
4104	iter->snapshot = snapshot;
4105	iter->pos = -1;
4106	iter->cpu_file = tracing_get_cpu(inode);
4107	mutex_init(&iter->mutex);
4108
4109	/* Notify the tracer early; before we stop tracing. */
4110	if (iter->trace && iter->trace->open)
4111		iter->trace->open(iter);
4112
4113	/* Annotate start of buffers if we had overruns */
4114	if (ring_buffer_overruns(iter->trace_buffer->buffer))
4115		iter->iter_flags |= TRACE_FILE_ANNOTATE;
4116
4117	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
4118	if (trace_clocks[tr->clock_id].in_ns)
4119		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4120
4121	/* stop the trace while dumping if we are not opening "snapshot" */
4122	if (!iter->snapshot)
 
 
 
4123		tracing_stop_tr(tr);
4124
4125	if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4126		for_each_tracing_cpu(cpu) {
4127			iter->buffer_iter[cpu] =
4128				ring_buffer_read_prepare(iter->trace_buffer->buffer,
4129							 cpu, GFP_KERNEL);
4130		}
4131		ring_buffer_read_prepare_sync();
4132		for_each_tracing_cpu(cpu) {
4133			ring_buffer_read_start(iter->buffer_iter[cpu]);
4134			tracing_iter_reset(iter, cpu);
4135		}
4136	} else {
4137		cpu = iter->cpu_file;
4138		iter->buffer_iter[cpu] =
4139			ring_buffer_read_prepare(iter->trace_buffer->buffer,
4140						 cpu, GFP_KERNEL);
4141		ring_buffer_read_prepare_sync();
4142		ring_buffer_read_start(iter->buffer_iter[cpu]);
4143		tracing_iter_reset(iter, cpu);
4144	}
4145
4146	mutex_unlock(&trace_types_lock);
4147
4148	return iter;
4149
4150 fail:
4151	mutex_unlock(&trace_types_lock);
4152	kfree(iter->trace);
 
4153	kfree(iter->buffer_iter);
4154release:
4155	seq_release_private(inode, file);
4156	return ERR_PTR(-ENOMEM);
4157}
4158
4159int tracing_open_generic(struct inode *inode, struct file *filp)
4160{
4161	int ret;
4162
4163	ret = tracing_check_open_get_tr(NULL);
4164	if (ret)
4165		return ret;
4166
4167	filp->private_data = inode->i_private;
4168	return 0;
4169}
4170
4171bool tracing_is_disabled(void)
4172{
4173	return (tracing_disabled) ? true: false;
4174}
4175
4176/*
4177 * Open and update trace_array ref count.
4178 * Must have the current trace_array passed to it.
4179 */
4180int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4181{
4182	struct trace_array *tr = inode->i_private;
4183	int ret;
4184
4185	ret = tracing_check_open_get_tr(tr);
4186	if (ret)
4187		return ret;
4188
4189	filp->private_data = inode->i_private;
4190
4191	return 0;
4192}
4193
4194static int tracing_release(struct inode *inode, struct file *file)
4195{
4196	struct trace_array *tr = inode->i_private;
4197	struct seq_file *m = file->private_data;
4198	struct trace_iterator *iter;
4199	int cpu;
4200
4201	if (!(file->f_mode & FMODE_READ)) {
4202		trace_array_put(tr);
4203		return 0;
4204	}
4205
4206	/* Writes do not use seq_file */
4207	iter = m->private;
4208	mutex_lock(&trace_types_lock);
4209
4210	for_each_tracing_cpu(cpu) {
4211		if (iter->buffer_iter[cpu])
4212			ring_buffer_read_finish(iter->buffer_iter[cpu]);
4213	}
4214
4215	if (iter->trace && iter->trace->close)
4216		iter->trace->close(iter);
4217
4218	if (!iter->snapshot)
4219		/* reenable tracing if it was previously enabled */
4220		tracing_start_tr(tr);
4221
4222	__trace_array_put(tr);
4223
4224	mutex_unlock(&trace_types_lock);
4225
4226	mutex_destroy(&iter->mutex);
4227	free_cpumask_var(iter->started);
 
 
4228	kfree(iter->trace);
4229	kfree(iter->buffer_iter);
4230	seq_release_private(inode, file);
4231
4232	return 0;
4233}
4234
4235static int tracing_release_generic_tr(struct inode *inode, struct file *file)
4236{
4237	struct trace_array *tr = inode->i_private;
4238
4239	trace_array_put(tr);
4240	return 0;
4241}
4242
4243static int tracing_single_release_tr(struct inode *inode, struct file *file)
4244{
4245	struct trace_array *tr = inode->i_private;
4246
4247	trace_array_put(tr);
4248
4249	return single_release(inode, file);
4250}
4251
4252static int tracing_open(struct inode *inode, struct file *file)
4253{
4254	struct trace_array *tr = inode->i_private;
4255	struct trace_iterator *iter;
4256	int ret;
4257
4258	ret = tracing_check_open_get_tr(tr);
4259	if (ret)
4260		return ret;
4261
4262	/* If this file was open for write, then erase contents */
4263	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
4264		int cpu = tracing_get_cpu(inode);
4265		struct trace_buffer *trace_buf = &tr->trace_buffer;
4266
4267#ifdef CONFIG_TRACER_MAX_TRACE
4268		if (tr->current_trace->print_max)
4269			trace_buf = &tr->max_buffer;
4270#endif
4271
4272		if (cpu == RING_BUFFER_ALL_CPUS)
4273			tracing_reset_online_cpus(trace_buf);
4274		else
4275			tracing_reset_cpu(trace_buf, cpu);
4276	}
4277
4278	if (file->f_mode & FMODE_READ) {
4279		iter = __tracing_open(inode, file, false);
4280		if (IS_ERR(iter))
4281			ret = PTR_ERR(iter);
4282		else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4283			iter->iter_flags |= TRACE_FILE_LAT_FMT;
4284	}
4285
4286	if (ret < 0)
4287		trace_array_put(tr);
4288
4289	return ret;
4290}
4291
4292/*
4293 * Some tracers are not suitable for instance buffers.
4294 * A tracer is always available for the global array (toplevel)
4295 * or if it explicitly states that it is.
4296 */
4297static bool
4298trace_ok_for_array(struct tracer *t, struct trace_array *tr)
4299{
4300	return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
4301}
4302
4303/* Find the next tracer that this trace array may use */
4304static struct tracer *
4305get_tracer_for_array(struct trace_array *tr, struct tracer *t)
4306{
4307	while (t && !trace_ok_for_array(t, tr))
4308		t = t->next;
4309
4310	return t;
4311}
4312
4313static void *
4314t_next(struct seq_file *m, void *v, loff_t *pos)
4315{
4316	struct trace_array *tr = m->private;
4317	struct tracer *t = v;
4318
4319	(*pos)++;
4320
4321	if (t)
4322		t = get_tracer_for_array(tr, t->next);
4323
4324	return t;
4325}
4326
4327static void *t_start(struct seq_file *m, loff_t *pos)
4328{
4329	struct trace_array *tr = m->private;
4330	struct tracer *t;
4331	loff_t l = 0;
4332
4333	mutex_lock(&trace_types_lock);
4334
4335	t = get_tracer_for_array(tr, trace_types);
4336	for (; t && l < *pos; t = t_next(m, t, &l))
4337			;
4338
4339	return t;
4340}
4341
4342static void t_stop(struct seq_file *m, void *p)
4343{
4344	mutex_unlock(&trace_types_lock);
4345}
4346
4347static int t_show(struct seq_file *m, void *v)
4348{
4349	struct tracer *t = v;
4350
4351	if (!t)
4352		return 0;
4353
4354	seq_puts(m, t->name);
4355	if (t->next)
4356		seq_putc(m, ' ');
4357	else
4358		seq_putc(m, '\n');
4359
4360	return 0;
4361}
4362
4363static const struct seq_operations show_traces_seq_ops = {
4364	.start		= t_start,
4365	.next		= t_next,
4366	.stop		= t_stop,
4367	.show		= t_show,
4368};
4369
4370static int show_traces_open(struct inode *inode, struct file *file)
4371{
4372	struct trace_array *tr = inode->i_private;
4373	struct seq_file *m;
4374	int ret;
4375
4376	ret = tracing_check_open_get_tr(tr);
4377	if (ret)
4378		return ret;
4379
4380	ret = seq_open(file, &show_traces_seq_ops);
4381	if (ret) {
4382		trace_array_put(tr);
4383		return ret;
4384	}
4385
4386	m = file->private_data;
4387	m->private = tr;
4388
4389	return 0;
4390}
4391
4392static int show_traces_release(struct inode *inode, struct file *file)
4393{
4394	struct trace_array *tr = inode->i_private;
4395
4396	trace_array_put(tr);
4397	return seq_release(inode, file);
4398}
4399
4400static ssize_t
4401tracing_write_stub(struct file *filp, const char __user *ubuf,
4402		   size_t count, loff_t *ppos)
4403{
4404	return count;
4405}
4406
4407loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
4408{
4409	int ret;
4410
4411	if (file->f_mode & FMODE_READ)
4412		ret = seq_lseek(file, offset, whence);
4413	else
4414		file->f_pos = ret = 0;
4415
4416	return ret;
4417}
4418
4419static const struct file_operations tracing_fops = {
4420	.open		= tracing_open,
4421	.read		= seq_read,
4422	.write		= tracing_write_stub,
4423	.llseek		= tracing_lseek,
4424	.release	= tracing_release,
4425};
4426
4427static const struct file_operations show_traces_fops = {
4428	.open		= show_traces_open,
4429	.read		= seq_read,
4430	.llseek		= seq_lseek,
4431	.release	= show_traces_release,
4432};
4433
4434static ssize_t
4435tracing_cpumask_read(struct file *filp, char __user *ubuf,
4436		     size_t count, loff_t *ppos)
4437{
4438	struct trace_array *tr = file_inode(filp)->i_private;
4439	char *mask_str;
4440	int len;
4441
4442	len = snprintf(NULL, 0, "%*pb\n",
4443		       cpumask_pr_args(tr->tracing_cpumask)) + 1;
4444	mask_str = kmalloc(len, GFP_KERNEL);
4445	if (!mask_str)
4446		return -ENOMEM;
4447
4448	len = snprintf(mask_str, len, "%*pb\n",
4449		       cpumask_pr_args(tr->tracing_cpumask));
4450	if (len >= count) {
4451		count = -EINVAL;
4452		goto out_err;
4453	}
4454	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
4455
4456out_err:
4457	kfree(mask_str);
4458
4459	return count;
4460}
4461
4462static ssize_t
4463tracing_cpumask_write(struct file *filp, const char __user *ubuf,
4464		      size_t count, loff_t *ppos)
4465{
4466	struct trace_array *tr = file_inode(filp)->i_private;
4467	cpumask_var_t tracing_cpumask_new;
4468	int err, cpu;
4469
4470	if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
4471		return -ENOMEM;
4472
4473	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
4474	if (err)
4475		goto err_unlock;
4476
4477	local_irq_disable();
4478	arch_spin_lock(&tr->max_lock);
4479	for_each_tracing_cpu(cpu) {
4480		/*
4481		 * Increase/decrease the disabled counter if we are
4482		 * about to flip a bit in the cpumask:
4483		 */
4484		if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4485				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4486			atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4487			ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
4488		}
4489		if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
4490				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
4491			atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
4492			ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
4493		}
4494	}
4495	arch_spin_unlock(&tr->max_lock);
4496	local_irq_enable();
4497
4498	cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4499	free_cpumask_var(tracing_cpumask_new);
4500
4501	return count;
4502
4503err_unlock:
4504	free_cpumask_var(tracing_cpumask_new);
4505
4506	return err;
4507}
4508
4509static const struct file_operations tracing_cpumask_fops = {
4510	.open		= tracing_open_generic_tr,
4511	.read		= tracing_cpumask_read,
4512	.write		= tracing_cpumask_write,
4513	.release	= tracing_release_generic_tr,
4514	.llseek		= generic_file_llseek,
4515};
4516
4517static int tracing_trace_options_show(struct seq_file *m, void *v)
4518{
4519	struct tracer_opt *trace_opts;
4520	struct trace_array *tr = m->private;
4521	u32 tracer_flags;
4522	int i;
4523
4524	mutex_lock(&trace_types_lock);
4525	tracer_flags = tr->current_trace->flags->val;
4526	trace_opts = tr->current_trace->flags->opts;
4527
4528	for (i = 0; trace_options[i]; i++) {
4529		if (tr->trace_flags & (1 << i))
4530			seq_printf(m, "%s\n", trace_options[i]);
4531		else
4532			seq_printf(m, "no%s\n", trace_options[i]);
4533	}
4534
4535	for (i = 0; trace_opts[i].name; i++) {
4536		if (tracer_flags & trace_opts[i].bit)
4537			seq_printf(m, "%s\n", trace_opts[i].name);
4538		else
4539			seq_printf(m, "no%s\n", trace_opts[i].name);
4540	}
4541	mutex_unlock(&trace_types_lock);
4542
4543	return 0;
4544}
4545
4546static int __set_tracer_option(struct trace_array *tr,
4547			       struct tracer_flags *tracer_flags,
4548			       struct tracer_opt *opts, int neg)
4549{
4550	struct tracer *trace = tracer_flags->trace;
4551	int ret;
4552
4553	ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
4554	if (ret)
4555		return ret;
4556
4557	if (neg)
4558		tracer_flags->val &= ~opts->bit;
4559	else
4560		tracer_flags->val |= opts->bit;
4561	return 0;
4562}
4563
4564/* Try to assign a tracer specific option */
4565static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
4566{
4567	struct tracer *trace = tr->current_trace;
4568	struct tracer_flags *tracer_flags = trace->flags;
4569	struct tracer_opt *opts = NULL;
4570	int i;
4571
4572	for (i = 0; tracer_flags->opts[i].name; i++) {
4573		opts = &tracer_flags->opts[i];
4574
4575		if (strcmp(cmp, opts->name) == 0)
4576			return __set_tracer_option(tr, trace->flags, opts, neg);
4577	}
4578
4579	return -EINVAL;
4580}
4581
4582/* Some tracers require overwrite to stay enabled */
4583int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
4584{
4585	if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
4586		return -1;
4587
4588	return 0;
4589}
4590
4591int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
4592{
 
 
 
 
 
 
4593	/* do nothing if flag is already set */
4594	if (!!(tr->trace_flags & mask) == !!enabled)
4595		return 0;
4596
4597	/* Give the tracer a chance to approve the change */
4598	if (tr->current_trace->flag_changed)
4599		if (tr->current_trace->flag_changed(tr, mask, !!enabled))
4600			return -EINVAL;
4601
4602	if (enabled)
4603		tr->trace_flags |= mask;
4604	else
4605		tr->trace_flags &= ~mask;
4606
4607	if (mask == TRACE_ITER_RECORD_CMD)
4608		trace_event_enable_cmd_record(enabled);
4609
4610	if (mask == TRACE_ITER_RECORD_TGID) {
4611		if (!tgid_map)
4612			tgid_map = kcalloc(PID_MAX_DEFAULT + 1,
4613					   sizeof(*tgid_map),
4614					   GFP_KERNEL);
 
 
 
 
 
 
 
 
 
4615		if (!tgid_map) {
4616			tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
4617			return -ENOMEM;
4618		}
4619
4620		trace_event_enable_tgid_record(enabled);
4621	}
4622
4623	if (mask == TRACE_ITER_EVENT_FORK)
4624		trace_event_follow_fork(tr, enabled);
4625
4626	if (mask == TRACE_ITER_FUNC_FORK)
4627		ftrace_pid_follow_fork(tr, enabled);
4628
4629	if (mask == TRACE_ITER_OVERWRITE) {
4630		ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
4631#ifdef CONFIG_TRACER_MAX_TRACE
4632		ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
4633#endif
4634	}
4635
4636	if (mask == TRACE_ITER_PRINTK) {
4637		trace_printk_start_stop_comm(enabled);
4638		trace_printk_control(enabled);
4639	}
4640
4641	return 0;
4642}
4643
4644static int trace_set_options(struct trace_array *tr, char *option)
4645{
4646	char *cmp;
4647	int neg = 0;
4648	int ret;
4649	size_t orig_len = strlen(option);
4650	int len;
4651
4652	cmp = strstrip(option);
4653
4654	len = str_has_prefix(cmp, "no");
4655	if (len)
4656		neg = 1;
4657
4658	cmp += len;
4659
 
4660	mutex_lock(&trace_types_lock);
4661
4662	ret = match_string(trace_options, -1, cmp);
4663	/* If no option could be set, test the specific tracer options */
4664	if (ret < 0)
4665		ret = set_tracer_option(tr, cmp, neg);
4666	else
4667		ret = set_tracer_flag(tr, 1 << ret, !neg);
4668
4669	mutex_unlock(&trace_types_lock);
 
4670
4671	/*
4672	 * If the first trailing whitespace is replaced with '\0' by strstrip,
4673	 * turn it back into a space.
4674	 */
4675	if (orig_len > strlen(option))
4676		option[strlen(option)] = ' ';
4677
4678	return ret;
4679}
4680
4681static void __init apply_trace_boot_options(void)
4682{
4683	char *buf = trace_boot_options_buf;
4684	char *option;
4685
4686	while (true) {
4687		option = strsep(&buf, ",");
4688
4689		if (!option)
4690			break;
4691
4692		if (*option)
4693			trace_set_options(&global_trace, option);
4694
4695		/* Put back the comma to allow this to be called again */
4696		if (buf)
4697			*(buf - 1) = ',';
4698	}
4699}
4700
4701static ssize_t
4702tracing_trace_options_write(struct file *filp, const char __user *ubuf,
4703			size_t cnt, loff_t *ppos)
4704{
4705	struct seq_file *m = filp->private_data;
4706	struct trace_array *tr = m->private;
4707	char buf[64];
4708	int ret;
4709
4710	if (cnt >= sizeof(buf))
4711		return -EINVAL;
4712
4713	if (copy_from_user(buf, ubuf, cnt))
4714		return -EFAULT;
4715
4716	buf[cnt] = 0;
4717
4718	ret = trace_set_options(tr, buf);
4719	if (ret < 0)
4720		return ret;
4721
4722	*ppos += cnt;
4723
4724	return cnt;
4725}
4726
4727static int tracing_trace_options_open(struct inode *inode, struct file *file)
4728{
4729	struct trace_array *tr = inode->i_private;
4730	int ret;
4731
4732	ret = tracing_check_open_get_tr(tr);
4733	if (ret)
4734		return ret;
4735
4736	ret = single_open(file, tracing_trace_options_show, inode->i_private);
4737	if (ret < 0)
4738		trace_array_put(tr);
4739
4740	return ret;
4741}
4742
4743static const struct file_operations tracing_iter_fops = {
4744	.open		= tracing_trace_options_open,
4745	.read		= seq_read,
4746	.llseek		= seq_lseek,
4747	.release	= tracing_single_release_tr,
4748	.write		= tracing_trace_options_write,
4749};
4750
4751static const char readme_msg[] =
4752	"tracing mini-HOWTO:\n\n"
4753	"# echo 0 > tracing_on : quick way to disable tracing\n"
4754	"# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
4755	" Important files:\n"
4756	"  trace\t\t\t- The static contents of the buffer\n"
4757	"\t\t\t  To clear the buffer write into this file: echo > trace\n"
4758	"  trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
4759	"  current_tracer\t- function and latency tracers\n"
4760	"  available_tracers\t- list of configured tracers for current_tracer\n"
4761	"  error_log\t- error log for failed commands (that support it)\n"
4762	"  buffer_size_kb\t- view and modify size of per cpu buffer\n"
4763	"  buffer_total_size_kb  - view total size of all cpu buffers\n\n"
4764	"  trace_clock\t\t-change the clock used to order events\n"
4765	"       local:   Per cpu clock but may not be synced across CPUs\n"
4766	"      global:   Synced across CPUs but slows tracing down.\n"
4767	"     counter:   Not a clock, but just an increment\n"
4768	"      uptime:   Jiffy counter from time of boot\n"
4769	"        perf:   Same clock that perf events use\n"
4770#ifdef CONFIG_X86_64
4771	"     x86-tsc:   TSC cycle counter\n"
4772#endif
4773	"\n  timestamp_mode\t-view the mode used to timestamp events\n"
4774	"       delta:   Delta difference against a buffer-wide timestamp\n"
4775	"    absolute:   Absolute (standalone) timestamp\n"
4776	"\n  trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
4777	"\n  trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
4778	"  tracing_cpumask\t- Limit which CPUs to trace\n"
4779	"  instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
4780	"\t\t\t  Remove sub-buffer with rmdir\n"
4781	"  trace_options\t\t- Set format or modify how tracing happens\n"
4782	"\t\t\t  Disable an option by prefixing 'no' to the\n"
4783	"\t\t\t  option name\n"
4784	"  saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
4785#ifdef CONFIG_DYNAMIC_FTRACE
4786	"\n  available_filter_functions - list of functions that can be filtered on\n"
4787	"  set_ftrace_filter\t- echo function name in here to only trace these\n"
4788	"\t\t\t  functions\n"
4789	"\t     accepts: func_full_name or glob-matching-pattern\n"
4790	"\t     modules: Can select a group via module\n"
4791	"\t      Format: :mod:<module-name>\n"
4792	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"
4793	"\t    triggers: a command to perform when function is hit\n"
4794	"\t      Format: <function>:<trigger>[:count]\n"
4795	"\t     trigger: traceon, traceoff\n"
4796	"\t\t      enable_event:<system>:<event>\n"
4797	"\t\t      disable_event:<system>:<event>\n"
4798#ifdef CONFIG_STACKTRACE
4799	"\t\t      stacktrace\n"
4800#endif
4801#ifdef CONFIG_TRACER_SNAPSHOT
4802	"\t\t      snapshot\n"
4803#endif
4804	"\t\t      dump\n"
4805	"\t\t      cpudump\n"
4806	"\t     example: echo do_fault:traceoff > set_ftrace_filter\n"
4807	"\t              echo do_trap:traceoff:3 > set_ftrace_filter\n"
4808	"\t     The first one will disable tracing every time do_fault is hit\n"
4809	"\t     The second will disable tracing at most 3 times when do_trap is hit\n"
4810	"\t       The first time do trap is hit and it disables tracing, the\n"
4811	"\t       counter will decrement to 2. If tracing is already disabled,\n"
4812	"\t       the counter will not decrement. It only decrements when the\n"
4813	"\t       trigger did work\n"
4814	"\t     To remove trigger without count:\n"
4815	"\t       echo '!<function>:<trigger> > set_ftrace_filter\n"
4816	"\t     To remove trigger with a count:\n"
4817	"\t       echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
4818	"  set_ftrace_notrace\t- echo function name in here to never trace.\n"
4819	"\t    accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
4820	"\t    modules: Can select a group via module command :mod:\n"
4821	"\t    Does not accept triggers\n"
4822#endif /* CONFIG_DYNAMIC_FTRACE */
4823#ifdef CONFIG_FUNCTION_TRACER
4824	"  set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
4825	"\t\t    (function)\n"
 
 
4826#endif
4827#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4828	"  set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
4829	"  set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
4830	"  max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
4831#endif
4832#ifdef CONFIG_TRACER_SNAPSHOT
4833	"\n  snapshot\t\t- Like 'trace' but shows the content of the static\n"
4834	"\t\t\t  snapshot buffer. Read the contents for more\n"
4835	"\t\t\t  information\n"
4836#endif
4837#ifdef CONFIG_STACK_TRACER
4838	"  stack_trace\t\t- Shows the max stack trace when active\n"
4839	"  stack_max_size\t- Shows current max stack size that was traced\n"
4840	"\t\t\t  Write into this file to reset the max size (trigger a\n"
4841	"\t\t\t  new trace)\n"
4842#ifdef CONFIG_DYNAMIC_FTRACE
4843	"  stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
4844	"\t\t\t  traces\n"
4845#endif
4846#endif /* CONFIG_STACK_TRACER */
4847#ifdef CONFIG_DYNAMIC_EVENTS
4848	"  dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
4849	"\t\t\t  Write into this file to define/undefine new trace events.\n"
4850#endif
4851#ifdef CONFIG_KPROBE_EVENTS
4852	"  kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
4853	"\t\t\t  Write into this file to define/undefine new trace events.\n"
4854#endif
4855#ifdef CONFIG_UPROBE_EVENTS
4856	"  uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
4857	"\t\t\t  Write into this file to define/undefine new trace events.\n"
4858#endif
4859#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
4860	"\t  accepts: event-definitions (one definition per line)\n"
4861	"\t   Format: p[:[<group>/]<event>] <place> [<args>]\n"
4862	"\t           r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
4863#ifdef CONFIG_HIST_TRIGGERS
4864	"\t           s:[synthetic/]<event> <field> [<field>]\n"
4865#endif
4866	"\t           -:[<group>/]<event>\n"
4867#ifdef CONFIG_KPROBE_EVENTS
4868	"\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
4869  "place (kretprobe): [<module>:]<symbol>[+<offset>]|<memaddr>\n"
4870#endif
4871#ifdef CONFIG_UPROBE_EVENTS
4872  "   place (uprobe): <path>:<offset>[(ref_ctr_offset)]\n"
4873#endif
4874	"\t     args: <name>=fetcharg[:type]\n"
4875	"\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
4876#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
4877	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
4878#else
4879	"\t           $stack<index>, $stack, $retval, $comm,\n"
4880#endif
4881	"\t           +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
4882	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
4883	"\t           b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
4884	"\t           <type>\\[<array-size>\\]\n"
4885#ifdef CONFIG_HIST_TRIGGERS
4886	"\t    field: <stype> <name>;\n"
4887	"\t    stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
4888	"\t           [unsigned] char/int/long\n"
4889#endif
4890#endif
4891	"  events/\t\t- Directory containing all trace event subsystems:\n"
4892	"      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
4893	"  events/<system>/\t- Directory containing all trace events for <system>:\n"
4894	"      enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
4895	"\t\t\t  events\n"
4896	"      filter\t\t- If set, only events passing filter are traced\n"
4897	"  events/<system>/<event>/\t- Directory containing control files for\n"
4898	"\t\t\t  <event>:\n"
4899	"      enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
4900	"      filter\t\t- If set, only events passing filter are traced\n"
4901	"      trigger\t\t- If set, a command to perform when event is hit\n"
4902	"\t    Format: <trigger>[:count][if <filter>]\n"
4903	"\t   trigger: traceon, traceoff\n"
4904	"\t            enable_event:<system>:<event>\n"
4905	"\t            disable_event:<system>:<event>\n"
4906#ifdef CONFIG_HIST_TRIGGERS
4907	"\t            enable_hist:<system>:<event>\n"
4908	"\t            disable_hist:<system>:<event>\n"
4909#endif
4910#ifdef CONFIG_STACKTRACE
4911	"\t\t    stacktrace\n"
4912#endif
4913#ifdef CONFIG_TRACER_SNAPSHOT
4914	"\t\t    snapshot\n"
4915#endif
4916#ifdef CONFIG_HIST_TRIGGERS
4917	"\t\t    hist (see below)\n"
4918#endif
4919	"\t   example: echo traceoff > events/block/block_unplug/trigger\n"
4920	"\t            echo traceoff:3 > events/block/block_unplug/trigger\n"
4921	"\t            echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
4922	"\t                  events/block/block_unplug/trigger\n"
4923	"\t   The first disables tracing every time block_unplug is hit.\n"
4924	"\t   The second disables tracing the first 3 times block_unplug is hit.\n"
4925	"\t   The third enables the kmalloc event the first 3 times block_unplug\n"
4926	"\t     is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
4927	"\t   Like function triggers, the counter is only decremented if it\n"
4928	"\t    enabled or disabled tracing.\n"
4929	"\t   To remove a trigger without a count:\n"
4930	"\t     echo '!<trigger> > <system>/<event>/trigger\n"
4931	"\t   To remove a trigger with a count:\n"
4932	"\t     echo '!<trigger>:0 > <system>/<event>/trigger\n"
4933	"\t   Filters can be ignored when removing a trigger.\n"
4934#ifdef CONFIG_HIST_TRIGGERS
4935	"      hist trigger\t- If set, event hits are aggregated into a hash table\n"
4936	"\t    Format: hist:keys=<field1[,field2,...]>\n"
4937	"\t            [:values=<field1[,field2,...]>]\n"
4938	"\t            [:sort=<field1[,field2,...]>]\n"
4939	"\t            [:size=#entries]\n"
4940	"\t            [:pause][:continue][:clear]\n"
4941	"\t            [:name=histname1]\n"
4942	"\t            [:<handler>.<action>]\n"
4943	"\t            [if <filter>]\n\n"
 
 
 
 
4944	"\t    When a matching event is hit, an entry is added to a hash\n"
4945	"\t    table using the key(s) and value(s) named, and the value of a\n"
4946	"\t    sum called 'hitcount' is incremented.  Keys and values\n"
4947	"\t    correspond to fields in the event's format description.  Keys\n"
4948	"\t    can be any field, or the special string 'stacktrace'.\n"
4949	"\t    Compound keys consisting of up to two fields can be specified\n"
4950	"\t    by the 'keys' keyword.  Values must correspond to numeric\n"
4951	"\t    fields.  Sort keys consisting of up to two fields can be\n"
4952	"\t    specified using the 'sort' keyword.  The sort direction can\n"
4953	"\t    be modified by appending '.descending' or '.ascending' to a\n"
4954	"\t    sort field.  The 'size' parameter can be used to specify more\n"
4955	"\t    or fewer than the default 2048 entries for the hashtable size.\n"
4956	"\t    If a hist trigger is given a name using the 'name' parameter,\n"
4957	"\t    its histogram data will be shared with other triggers of the\n"
4958	"\t    same name, and trigger hits will update this common data.\n\n"
4959	"\t    Reading the 'hist' file for the event will dump the hash\n"
4960	"\t    table in its entirety to stdout.  If there are multiple hist\n"
4961	"\t    triggers attached to an event, there will be a table for each\n"
4962	"\t    trigger in the output.  The table displayed for a named\n"
4963	"\t    trigger will be the same as any other instance having the\n"
4964	"\t    same name.  The default format used to display a given field\n"
4965	"\t    can be modified by appending any of the following modifiers\n"
4966	"\t    to the field name, as applicable:\n\n"
4967	"\t            .hex        display a number as a hex value\n"
4968	"\t            .sym        display an address as a symbol\n"
4969	"\t            .sym-offset display an address as a symbol and offset\n"
4970	"\t            .execname   display a common_pid as a program name\n"
4971	"\t            .syscall    display a syscall id as a syscall name\n"
4972	"\t            .log2       display log2 value rather than raw number\n"
4973	"\t            .usecs      display a common_timestamp in microseconds\n\n"
4974	"\t    The 'pause' parameter can be used to pause an existing hist\n"
4975	"\t    trigger or to start a hist trigger but not log any events\n"
4976	"\t    until told to do so.  'continue' can be used to start or\n"
4977	"\t    restart a paused hist trigger.\n\n"
4978	"\t    The 'clear' parameter will clear the contents of a running\n"
4979	"\t    hist trigger and leave its current paused/active state\n"
4980	"\t    unchanged.\n\n"
4981	"\t    The enable_hist and disable_hist triggers can be used to\n"
4982	"\t    have one event conditionally start and stop another event's\n"
4983	"\t    already-attached hist trigger.  The syntax is analogous to\n"
4984	"\t    the enable_event and disable_event triggers.\n\n"
4985	"\t    Hist trigger handlers and actions are executed whenever a\n"
4986	"\t    a histogram entry is added or updated.  They take the form:\n\n"
4987	"\t        <handler>.<action>\n\n"
4988	"\t    The available handlers are:\n\n"
4989	"\t        onmatch(matching.event)  - invoke on addition or update\n"
4990	"\t        onmax(var)               - invoke if var exceeds current max\n"
4991	"\t        onchange(var)            - invoke action if var changes\n\n"
4992	"\t    The available actions are:\n\n"
4993	"\t        trace(<synthetic_event>,param list)  - generate synthetic event\n"
4994	"\t        save(field,...)                      - save current event fields\n"
4995#ifdef CONFIG_TRACER_SNAPSHOT
4996	"\t        snapshot()                           - snapshot the trace buffer\n"
 
 
 
 
 
4997#endif
4998#endif
4999;
5000
5001static ssize_t
5002tracing_readme_read(struct file *filp, char __user *ubuf,
5003		       size_t cnt, loff_t *ppos)
5004{
5005	return simple_read_from_buffer(ubuf, cnt, ppos,
5006					readme_msg, strlen(readme_msg));
5007}
5008
5009static const struct file_operations tracing_readme_fops = {
5010	.open		= tracing_open_generic,
5011	.read		= tracing_readme_read,
5012	.llseek		= generic_file_llseek,
5013};
5014
5015static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5016{
5017	int *ptr = v;
5018
5019	if (*pos || m->count)
5020		ptr++;
5021
5022	(*pos)++;
5023
5024	for (; ptr <= &tgid_map[PID_MAX_DEFAULT]; ptr++) {
5025		if (trace_find_tgid(*ptr))
5026			return ptr;
5027	}
5028
5029	return NULL;
5030}
5031
5032static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5033{
5034	void *v;
5035	loff_t l = 0;
5036
5037	if (!tgid_map)
5038		return NULL;
5039
5040	v = &tgid_map[0];
5041	while (l <= *pos) {
5042		v = saved_tgids_next(m, v, &l);
5043		if (!v)
5044			return NULL;
5045	}
5046
5047	return v;
5048}
5049
5050static void saved_tgids_stop(struct seq_file *m, void *v)
5051{
5052}
5053
5054static int saved_tgids_show(struct seq_file *m, void *v)
5055{
5056	int pid = (int *)v - tgid_map;
 
 
 
 
 
5057
5058	seq_printf(m, "%d %d\n", pid, trace_find_tgid(pid));
5059	return 0;
5060}
5061
5062static const struct seq_operations tracing_saved_tgids_seq_ops = {
5063	.start		= saved_tgids_start,
5064	.stop		= saved_tgids_stop,
5065	.next		= saved_tgids_next,
5066	.show		= saved_tgids_show,
5067};
5068
5069static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5070{
5071	int ret;
5072
5073	ret = tracing_check_open_get_tr(NULL);
5074	if (ret)
5075		return ret;
5076
5077	return seq_open(filp, &tracing_saved_tgids_seq_ops);
5078}
5079
5080
5081static const struct file_operations tracing_saved_tgids_fops = {
5082	.open		= tracing_saved_tgids_open,
5083	.read		= seq_read,
5084	.llseek		= seq_lseek,
5085	.release	= seq_release,
5086};
5087
5088static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5089{
5090	unsigned int *ptr = v;
5091
5092	if (*pos || m->count)
5093		ptr++;
5094
5095	(*pos)++;
5096
5097	for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5098	     ptr++) {
5099		if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
5100			continue;
5101
5102		return ptr;
5103	}
5104
5105	return NULL;
5106}
5107
5108static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
5109{
5110	void *v;
5111	loff_t l = 0;
5112
5113	preempt_disable();
5114	arch_spin_lock(&trace_cmdline_lock);
5115
5116	v = &savedcmd->map_cmdline_to_pid[0];
5117	while (l <= *pos) {
5118		v = saved_cmdlines_next(m, v, &l);
5119		if (!v)
5120			return NULL;
5121	}
5122
5123	return v;
5124}
5125
5126static void saved_cmdlines_stop(struct seq_file *m, void *v)
5127{
5128	arch_spin_unlock(&trace_cmdline_lock);
5129	preempt_enable();
5130}
5131
5132static int saved_cmdlines_show(struct seq_file *m, void *v)
5133{
5134	char buf[TASK_COMM_LEN];
5135	unsigned int *pid = v;
5136
5137	__trace_find_cmdline(*pid, buf);
5138	seq_printf(m, "%d %s\n", *pid, buf);
5139	return 0;
5140}
5141
5142static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
5143	.start		= saved_cmdlines_start,
5144	.next		= saved_cmdlines_next,
5145	.stop		= saved_cmdlines_stop,
5146	.show		= saved_cmdlines_show,
5147};
5148
5149static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
5150{
5151	int ret;
5152
5153	ret = tracing_check_open_get_tr(NULL);
5154	if (ret)
5155		return ret;
5156
5157	return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
5158}
5159
5160static const struct file_operations tracing_saved_cmdlines_fops = {
5161	.open		= tracing_saved_cmdlines_open,
5162	.read		= seq_read,
5163	.llseek		= seq_lseek,
5164	.release	= seq_release,
5165};
5166
5167static ssize_t
5168tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
5169				 size_t cnt, loff_t *ppos)
5170{
5171	char buf[64];
5172	int r;
5173
5174	arch_spin_lock(&trace_cmdline_lock);
5175	r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
5176	arch_spin_unlock(&trace_cmdline_lock);
5177
5178	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5179}
5180
5181static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
5182{
5183	kfree(s->saved_cmdlines);
5184	kfree(s->map_cmdline_to_pid);
5185	kfree(s);
5186}
5187
5188static int tracing_resize_saved_cmdlines(unsigned int val)
5189{
5190	struct saved_cmdlines_buffer *s, *savedcmd_temp;
5191
5192	s = kmalloc(sizeof(*s), GFP_KERNEL);
5193	if (!s)
5194		return -ENOMEM;
5195
5196	if (allocate_cmdlines_buffer(val, s) < 0) {
5197		kfree(s);
5198		return -ENOMEM;
5199	}
5200
5201	arch_spin_lock(&trace_cmdline_lock);
5202	savedcmd_temp = savedcmd;
5203	savedcmd = s;
5204	arch_spin_unlock(&trace_cmdline_lock);
5205	free_saved_cmdlines_buffer(savedcmd_temp);
5206
5207	return 0;
5208}
5209
5210static ssize_t
5211tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
5212				  size_t cnt, loff_t *ppos)
5213{
5214	unsigned long val;
5215	int ret;
5216
5217	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5218	if (ret)
5219		return ret;
5220
5221	/* must have at least 1 entry or less than PID_MAX_DEFAULT */
5222	if (!val || val > PID_MAX_DEFAULT)
5223		return -EINVAL;
5224
5225	ret = tracing_resize_saved_cmdlines((unsigned int)val);
5226	if (ret < 0)
5227		return ret;
5228
5229	*ppos += cnt;
5230
5231	return cnt;
5232}
5233
5234static const struct file_operations tracing_saved_cmdlines_size_fops = {
5235	.open		= tracing_open_generic,
5236	.read		= tracing_saved_cmdlines_size_read,
5237	.write		= tracing_saved_cmdlines_size_write,
5238};
5239
5240#ifdef CONFIG_TRACE_EVAL_MAP_FILE
5241static union trace_eval_map_item *
5242update_eval_map(union trace_eval_map_item *ptr)
5243{
5244	if (!ptr->map.eval_string) {
5245		if (ptr->tail.next) {
5246			ptr = ptr->tail.next;
5247			/* Set ptr to the next real item (skip head) */
5248			ptr++;
5249		} else
5250			return NULL;
5251	}
5252	return ptr;
5253}
5254
5255static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
5256{
5257	union trace_eval_map_item *ptr = v;
5258
5259	/*
5260	 * Paranoid! If ptr points to end, we don't want to increment past it.
5261	 * This really should never happen.
5262	 */
 
5263	ptr = update_eval_map(ptr);
5264	if (WARN_ON_ONCE(!ptr))
5265		return NULL;
5266
5267	ptr++;
5268
5269	(*pos)++;
5270
5271	ptr = update_eval_map(ptr);
5272
5273	return ptr;
5274}
5275
5276static void *eval_map_start(struct seq_file *m, loff_t *pos)
5277{
5278	union trace_eval_map_item *v;
5279	loff_t l = 0;
5280
5281	mutex_lock(&trace_eval_mutex);
5282
5283	v = trace_eval_maps;
5284	if (v)
5285		v++;
5286
5287	while (v && l < *pos) {
5288		v = eval_map_next(m, v, &l);
5289	}
5290
5291	return v;
5292}
5293
5294static void eval_map_stop(struct seq_file *m, void *v)
5295{
5296	mutex_unlock(&trace_eval_mutex);
5297}
5298
5299static int eval_map_show(struct seq_file *m, void *v)
5300{
5301	union trace_eval_map_item *ptr = v;
5302
5303	seq_printf(m, "%s %ld (%s)\n",
5304		   ptr->map.eval_string, ptr->map.eval_value,
5305		   ptr->map.system);
5306
5307	return 0;
5308}
5309
5310static const struct seq_operations tracing_eval_map_seq_ops = {
5311	.start		= eval_map_start,
5312	.next		= eval_map_next,
5313	.stop		= eval_map_stop,
5314	.show		= eval_map_show,
5315};
5316
5317static int tracing_eval_map_open(struct inode *inode, struct file *filp)
5318{
5319	int ret;
5320
5321	ret = tracing_check_open_get_tr(NULL);
5322	if (ret)
5323		return ret;
5324
5325	return seq_open(filp, &tracing_eval_map_seq_ops);
5326}
5327
5328static const struct file_operations tracing_eval_map_fops = {
5329	.open		= tracing_eval_map_open,
5330	.read		= seq_read,
5331	.llseek		= seq_lseek,
5332	.release	= seq_release,
5333};
5334
5335static inline union trace_eval_map_item *
5336trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
5337{
5338	/* Return tail of array given the head */
5339	return ptr + ptr->head.length + 1;
5340}
5341
5342static void
5343trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
5344			   int len)
5345{
5346	struct trace_eval_map **stop;
5347	struct trace_eval_map **map;
5348	union trace_eval_map_item *map_array;
5349	union trace_eval_map_item *ptr;
5350
5351	stop = start + len;
5352
5353	/*
5354	 * The trace_eval_maps contains the map plus a head and tail item,
5355	 * where the head holds the module and length of array, and the
5356	 * tail holds a pointer to the next list.
5357	 */
5358	map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
5359	if (!map_array) {
5360		pr_warn("Unable to allocate trace eval mapping\n");
5361		return;
5362	}
5363
5364	mutex_lock(&trace_eval_mutex);
5365
5366	if (!trace_eval_maps)
5367		trace_eval_maps = map_array;
5368	else {
5369		ptr = trace_eval_maps;
5370		for (;;) {
5371			ptr = trace_eval_jmp_to_tail(ptr);
5372			if (!ptr->tail.next)
5373				break;
5374			ptr = ptr->tail.next;
5375
5376		}
5377		ptr->tail.next = map_array;
5378	}
5379	map_array->head.mod = mod;
5380	map_array->head.length = len;
5381	map_array++;
5382
5383	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
5384		map_array->map = **map;
5385		map_array++;
5386	}
5387	memset(map_array, 0, sizeof(*map_array));
5388
5389	mutex_unlock(&trace_eval_mutex);
5390}
5391
5392static void trace_create_eval_file(struct dentry *d_tracer)
5393{
5394	trace_create_file("eval_map", 0444, d_tracer,
5395			  NULL, &tracing_eval_map_fops);
5396}
5397
5398#else /* CONFIG_TRACE_EVAL_MAP_FILE */
5399static inline void trace_create_eval_file(struct dentry *d_tracer) { }
5400static inline void trace_insert_eval_map_file(struct module *mod,
5401			      struct trace_eval_map **start, int len) { }
5402#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
5403
5404static void trace_insert_eval_map(struct module *mod,
5405				  struct trace_eval_map **start, int len)
5406{
5407	struct trace_eval_map **map;
5408
5409	if (len <= 0)
5410		return;
5411
5412	map = start;
5413
5414	trace_event_eval_update(map, len);
5415
5416	trace_insert_eval_map_file(mod, start, len);
5417}
5418
5419static ssize_t
5420tracing_set_trace_read(struct file *filp, char __user *ubuf,
5421		       size_t cnt, loff_t *ppos)
5422{
5423	struct trace_array *tr = filp->private_data;
5424	char buf[MAX_TRACER_SIZE+2];
5425	int r;
5426
5427	mutex_lock(&trace_types_lock);
5428	r = sprintf(buf, "%s\n", tr->current_trace->name);
5429	mutex_unlock(&trace_types_lock);
5430
5431	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5432}
5433
5434int tracer_init(struct tracer *t, struct trace_array *tr)
5435{
5436	tracing_reset_online_cpus(&tr->trace_buffer);
5437	return t->init(tr);
5438}
5439
5440static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
5441{
5442	int cpu;
5443
5444	for_each_tracing_cpu(cpu)
5445		per_cpu_ptr(buf->data, cpu)->entries = val;
5446}
5447
5448#ifdef CONFIG_TRACER_MAX_TRACE
5449/* resize @tr's buffer to the size of @size_tr's entries */
5450static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
5451					struct trace_buffer *size_buf, int cpu_id)
5452{
5453	int cpu, ret = 0;
5454
5455	if (cpu_id == RING_BUFFER_ALL_CPUS) {
5456		for_each_tracing_cpu(cpu) {
5457			ret = ring_buffer_resize(trace_buf->buffer,
5458				 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
5459			if (ret < 0)
5460				break;
5461			per_cpu_ptr(trace_buf->data, cpu)->entries =
5462				per_cpu_ptr(size_buf->data, cpu)->entries;
5463		}
5464	} else {
5465		ret = ring_buffer_resize(trace_buf->buffer,
5466				 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
5467		if (ret == 0)
5468			per_cpu_ptr(trace_buf->data, cpu_id)->entries =
5469				per_cpu_ptr(size_buf->data, cpu_id)->entries;
5470	}
5471
5472	return ret;
5473}
5474#endif /* CONFIG_TRACER_MAX_TRACE */
5475
5476static int __tracing_resize_ring_buffer(struct trace_array *tr,
5477					unsigned long size, int cpu)
5478{
5479	int ret;
5480
5481	/*
5482	 * If kernel or user changes the size of the ring buffer
5483	 * we use the size that was given, and we can forget about
5484	 * expanding it later.
5485	 */
5486	ring_buffer_expanded = true;
5487
5488	/* May be called before buffers are initialized */
5489	if (!tr->trace_buffer.buffer)
5490		return 0;
5491
5492	ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
5493	if (ret < 0)
5494		return ret;
5495
5496#ifdef CONFIG_TRACER_MAX_TRACE
5497	if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
5498	    !tr->current_trace->use_max_tr)
5499		goto out;
5500
5501	ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
5502	if (ret < 0) {
5503		int r = resize_buffer_duplicate_size(&tr->trace_buffer,
5504						     &tr->trace_buffer, cpu);
5505		if (r < 0) {
5506			/*
5507			 * AARGH! We are left with different
5508			 * size max buffer!!!!
5509			 * The max buffer is our "snapshot" buffer.
5510			 * When a tracer needs a snapshot (one of the
5511			 * latency tracers), it swaps the max buffer
5512			 * with the saved snap shot. We succeeded to
5513			 * update the size of the main buffer, but failed to
5514			 * update the size of the max buffer. But when we tried
5515			 * to reset the main buffer to the original size, we
5516			 * failed there too. This is very unlikely to
5517			 * happen, but if it does, warn and kill all
5518			 * tracing.
5519			 */
5520			WARN_ON(1);
5521			tracing_disabled = 1;
5522		}
5523		return ret;
5524	}
5525
5526	if (cpu == RING_BUFFER_ALL_CPUS)
5527		set_buffer_entries(&tr->max_buffer, size);
5528	else
5529		per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
5530
5531 out:
5532#endif /* CONFIG_TRACER_MAX_TRACE */
5533
5534	if (cpu == RING_BUFFER_ALL_CPUS)
5535		set_buffer_entries(&tr->trace_buffer, size);
5536	else
5537		per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
5538
5539	return ret;
5540}
5541
5542static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
5543					  unsigned long size, int cpu_id)
5544{
5545	int ret = size;
5546
5547	mutex_lock(&trace_types_lock);
5548
5549	if (cpu_id != RING_BUFFER_ALL_CPUS) {
5550		/* make sure, this cpu is enabled in the mask */
5551		if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
5552			ret = -EINVAL;
5553			goto out;
5554		}
5555	}
5556
5557	ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
5558	if (ret < 0)
5559		ret = -ENOMEM;
5560
5561out:
5562	mutex_unlock(&trace_types_lock);
5563
5564	return ret;
5565}
5566
5567
5568/**
5569 * tracing_update_buffers - used by tracing facility to expand ring buffers
5570 *
5571 * To save on memory when the tracing is never used on a system with it
5572 * configured in. The ring buffers are set to a minimum size. But once
5573 * a user starts to use the tracing facility, then they need to grow
5574 * to their default size.
5575 *
5576 * This function is to be called when a tracer is about to be used.
5577 */
5578int tracing_update_buffers(void)
5579{
5580	int ret = 0;
5581
5582	mutex_lock(&trace_types_lock);
5583	if (!ring_buffer_expanded)
5584		ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
5585						RING_BUFFER_ALL_CPUS);
5586	mutex_unlock(&trace_types_lock);
5587
5588	return ret;
5589}
5590
5591struct trace_option_dentry;
5592
5593static void
5594create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
5595
5596/*
5597 * Used to clear out the tracer before deletion of an instance.
5598 * Must have trace_types_lock held.
5599 */
5600static void tracing_set_nop(struct trace_array *tr)
5601{
5602	if (tr->current_trace == &nop_trace)
5603		return;
5604	
5605	tr->current_trace->enabled--;
5606
5607	if (tr->current_trace->reset)
5608		tr->current_trace->reset(tr);
5609
5610	tr->current_trace = &nop_trace;
5611}
5612
5613static void add_tracer_options(struct trace_array *tr, struct tracer *t)
5614{
5615	/* Only enable if the directory has been created already. */
5616	if (!tr->dir)
5617		return;
5618
5619	create_trace_option_files(tr, t);
5620}
5621
5622static int tracing_set_tracer(struct trace_array *tr, const char *buf)
5623{
5624	struct tracer *t;
5625#ifdef CONFIG_TRACER_MAX_TRACE
5626	bool had_max_tr;
5627#endif
5628	int ret = 0;
5629
5630	mutex_lock(&trace_types_lock);
5631
5632	if (!ring_buffer_expanded) {
5633		ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
5634						RING_BUFFER_ALL_CPUS);
5635		if (ret < 0)
5636			goto out;
5637		ret = 0;
5638	}
5639
5640	for (t = trace_types; t; t = t->next) {
5641		if (strcmp(t->name, buf) == 0)
5642			break;
5643	}
5644	if (!t) {
5645		ret = -EINVAL;
5646		goto out;
5647	}
5648	if (t == tr->current_trace)
5649		goto out;
5650
5651#ifdef CONFIG_TRACER_SNAPSHOT
5652	if (t->use_max_tr) {
5653		arch_spin_lock(&tr->max_lock);
5654		if (tr->cond_snapshot)
5655			ret = -EBUSY;
5656		arch_spin_unlock(&tr->max_lock);
5657		if (ret)
5658			goto out;
5659	}
5660#endif
5661	/* Some tracers won't work on kernel command line */
5662	if (system_state < SYSTEM_RUNNING && t->noboot) {
5663		pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
5664			t->name);
5665		goto out;
5666	}
5667
5668	/* Some tracers are only allowed for the top level buffer */
5669	if (!trace_ok_for_array(t, tr)) {
5670		ret = -EINVAL;
5671		goto out;
5672	}
5673
5674	/* If trace pipe files are being read, we can't change the tracer */
5675	if (tr->current_trace->ref) {
5676		ret = -EBUSY;
5677		goto out;
5678	}
5679
5680	trace_branch_disable();
5681
5682	tr->current_trace->enabled--;
5683
5684	if (tr->current_trace->reset)
5685		tr->current_trace->reset(tr);
5686
5687	/* Current trace needs to be nop_trace before synchronize_rcu */
5688	tr->current_trace = &nop_trace;
5689
5690#ifdef CONFIG_TRACER_MAX_TRACE
5691	had_max_tr = tr->allocated_snapshot;
5692
5693	if (had_max_tr && !t->use_max_tr) {
5694		/*
5695		 * We need to make sure that the update_max_tr sees that
5696		 * current_trace changed to nop_trace to keep it from
5697		 * swapping the buffers after we resize it.
5698		 * The update_max_tr is called from interrupts disabled
5699		 * so a synchronized_sched() is sufficient.
5700		 */
5701		synchronize_rcu();
5702		free_snapshot(tr);
5703	}
5704#endif
5705
5706#ifdef CONFIG_TRACER_MAX_TRACE
5707	if (t->use_max_tr && !had_max_tr) {
5708		ret = tracing_alloc_snapshot_instance(tr);
5709		if (ret < 0)
5710			goto out;
5711	}
5712#endif
5713
5714	if (t->init) {
5715		ret = tracer_init(t, tr);
5716		if (ret)
5717			goto out;
5718	}
5719
5720	tr->current_trace = t;
5721	tr->current_trace->enabled++;
5722	trace_branch_enable(tr);
5723 out:
5724	mutex_unlock(&trace_types_lock);
5725
5726	return ret;
5727}
5728
5729static ssize_t
5730tracing_set_trace_write(struct file *filp, const char __user *ubuf,
5731			size_t cnt, loff_t *ppos)
5732{
5733	struct trace_array *tr = filp->private_data;
5734	char buf[MAX_TRACER_SIZE+1];
5735	int i;
5736	size_t ret;
5737	int err;
5738
5739	ret = cnt;
5740
5741	if (cnt > MAX_TRACER_SIZE)
5742		cnt = MAX_TRACER_SIZE;
5743
5744	if (copy_from_user(buf, ubuf, cnt))
5745		return -EFAULT;
5746
5747	buf[cnt] = 0;
5748
5749	/* strip ending whitespace. */
5750	for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
5751		buf[i] = 0;
5752
5753	err = tracing_set_tracer(tr, buf);
5754	if (err)
5755		return err;
5756
5757	*ppos += ret;
5758
5759	return ret;
5760}
5761
5762static ssize_t
5763tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
5764		   size_t cnt, loff_t *ppos)
5765{
5766	char buf[64];
5767	int r;
5768
5769	r = snprintf(buf, sizeof(buf), "%ld\n",
5770		     *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
5771	if (r > sizeof(buf))
5772		r = sizeof(buf);
5773	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5774}
5775
5776static ssize_t
5777tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
5778		    size_t cnt, loff_t *ppos)
5779{
5780	unsigned long val;
5781	int ret;
5782
5783	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5784	if (ret)
5785		return ret;
5786
5787	*ptr = val * 1000;
5788
5789	return cnt;
5790}
5791
5792static ssize_t
5793tracing_thresh_read(struct file *filp, char __user *ubuf,
5794		    size_t cnt, loff_t *ppos)
5795{
5796	return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
5797}
5798
5799static ssize_t
5800tracing_thresh_write(struct file *filp, const char __user *ubuf,
5801		     size_t cnt, loff_t *ppos)
5802{
5803	struct trace_array *tr = filp->private_data;
5804	int ret;
5805
5806	mutex_lock(&trace_types_lock);
5807	ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
5808	if (ret < 0)
5809		goto out;
5810
5811	if (tr->current_trace->update_thresh) {
5812		ret = tr->current_trace->update_thresh(tr);
5813		if (ret < 0)
5814			goto out;
5815	}
5816
5817	ret = cnt;
5818out:
5819	mutex_unlock(&trace_types_lock);
5820
5821	return ret;
5822}
5823
5824#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
5825
5826static ssize_t
5827tracing_max_lat_read(struct file *filp, char __user *ubuf,
5828		     size_t cnt, loff_t *ppos)
5829{
5830	return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
5831}
5832
5833static ssize_t
5834tracing_max_lat_write(struct file *filp, const char __user *ubuf,
5835		      size_t cnt, loff_t *ppos)
5836{
5837	return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
5838}
5839
5840#endif
5841
5842static int tracing_open_pipe(struct inode *inode, struct file *filp)
5843{
5844	struct trace_array *tr = inode->i_private;
5845	struct trace_iterator *iter;
5846	int ret;
5847
5848	ret = tracing_check_open_get_tr(tr);
5849	if (ret)
5850		return ret;
5851
5852	mutex_lock(&trace_types_lock);
5853
5854	/* create a buffer to store the information to pass to userspace */
5855	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
5856	if (!iter) {
5857		ret = -ENOMEM;
5858		__trace_array_put(tr);
5859		goto out;
5860	}
5861
5862	trace_seq_init(&iter->seq);
5863	iter->trace = tr->current_trace;
5864
5865	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
5866		ret = -ENOMEM;
5867		goto fail;
5868	}
5869
5870	/* trace pipe does not show start of buffer */
5871	cpumask_setall(iter->started);
5872
5873	if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5874		iter->iter_flags |= TRACE_FILE_LAT_FMT;
5875
5876	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
5877	if (trace_clocks[tr->clock_id].in_ns)
5878		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
5879
5880	iter->tr = tr;
5881	iter->trace_buffer = &tr->trace_buffer;
5882	iter->cpu_file = tracing_get_cpu(inode);
5883	mutex_init(&iter->mutex);
5884	filp->private_data = iter;
5885
5886	if (iter->trace->pipe_open)
5887		iter->trace->pipe_open(iter);
5888
5889	nonseekable_open(inode, filp);
5890
5891	tr->current_trace->ref++;
5892out:
5893	mutex_unlock(&trace_types_lock);
5894	return ret;
5895
5896fail:
5897	kfree(iter);
5898	__trace_array_put(tr);
5899	mutex_unlock(&trace_types_lock);
5900	return ret;
5901}
5902
5903static int tracing_release_pipe(struct inode *inode, struct file *file)
5904{
5905	struct trace_iterator *iter = file->private_data;
5906	struct trace_array *tr = inode->i_private;
5907
5908	mutex_lock(&trace_types_lock);
5909
5910	tr->current_trace->ref--;
5911
5912	if (iter->trace->pipe_close)
5913		iter->trace->pipe_close(iter);
5914
5915	mutex_unlock(&trace_types_lock);
5916
5917	free_cpumask_var(iter->started);
5918	mutex_destroy(&iter->mutex);
5919	kfree(iter);
5920
5921	trace_array_put(tr);
5922
5923	return 0;
5924}
5925
5926static __poll_t
5927trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
5928{
5929	struct trace_array *tr = iter->tr;
5930
5931	/* Iterators are static, they should be filled or empty */
5932	if (trace_buffer_iter(iter, iter->cpu_file))
5933		return EPOLLIN | EPOLLRDNORM;
5934
5935	if (tr->trace_flags & TRACE_ITER_BLOCK)
5936		/*
5937		 * Always select as readable when in blocking mode
5938		 */
5939		return EPOLLIN | EPOLLRDNORM;
5940	else
5941		return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
5942					     filp, poll_table);
5943}
5944
5945static __poll_t
5946tracing_poll_pipe(struct file *filp, poll_table *poll_table)
5947{
5948	struct trace_iterator *iter = filp->private_data;
5949
5950	return trace_poll(iter, filp, poll_table);
5951}
5952
5953/* Must be called with iter->mutex held. */
5954static int tracing_wait_pipe(struct file *filp)
5955{
5956	struct trace_iterator *iter = filp->private_data;
5957	int ret;
5958
5959	while (trace_empty(iter)) {
5960
5961		if ((filp->f_flags & O_NONBLOCK)) {
5962			return -EAGAIN;
5963		}
5964
5965		/*
5966		 * We block until we read something and tracing is disabled.
5967		 * We still block if tracing is disabled, but we have never
5968		 * read anything. This allows a user to cat this file, and
5969		 * then enable tracing. But after we have read something,
5970		 * we give an EOF when tracing is again disabled.
5971		 *
5972		 * iter->pos will be 0 if we haven't read anything.
5973		 */
5974		if (!tracer_tracing_is_on(iter->tr) && iter->pos)
5975			break;
5976
5977		mutex_unlock(&iter->mutex);
5978
5979		ret = wait_on_pipe(iter, 0);
5980
5981		mutex_lock(&iter->mutex);
5982
5983		if (ret)
5984			return ret;
5985	}
5986
5987	return 1;
5988}
5989
5990/*
5991 * Consumer reader.
5992 */
5993static ssize_t
5994tracing_read_pipe(struct file *filp, char __user *ubuf,
5995		  size_t cnt, loff_t *ppos)
5996{
5997	struct trace_iterator *iter = filp->private_data;
5998	ssize_t sret;
5999
6000	/*
6001	 * Avoid more than one consumer on a single file descriptor
6002	 * This is just a matter of traces coherency, the ring buffer itself
6003	 * is protected.
6004	 */
6005	mutex_lock(&iter->mutex);
6006
6007	/* return any leftover data */
6008	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6009	if (sret != -EBUSY)
6010		goto out;
6011
6012	trace_seq_init(&iter->seq);
6013
6014	if (iter->trace->read) {
6015		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6016		if (sret)
6017			goto out;
6018	}
6019
6020waitagain:
6021	sret = tracing_wait_pipe(filp);
6022	if (sret <= 0)
6023		goto out;
6024
6025	/* stop when tracing is finished */
6026	if (trace_empty(iter)) {
6027		sret = 0;
6028		goto out;
6029	}
6030
6031	if (cnt >= PAGE_SIZE)
6032		cnt = PAGE_SIZE - 1;
6033
6034	/* reset all but tr, trace, and overruns */
6035	memset(&iter->seq, 0,
6036	       sizeof(struct trace_iterator) -
6037	       offsetof(struct trace_iterator, seq));
6038	cpumask_clear(iter->started);
6039	trace_seq_init(&iter->seq);
6040	iter->pos = -1;
6041
6042	trace_event_read_lock();
6043	trace_access_lock(iter->cpu_file);
6044	while (trace_find_next_entry_inc(iter) != NULL) {
6045		enum print_line_t ret;
6046		int save_len = iter->seq.seq.len;
6047
6048		ret = print_trace_line(iter);
6049		if (ret == TRACE_TYPE_PARTIAL_LINE) {
6050			/* don't print partial lines */
6051			iter->seq.seq.len = save_len;
6052			break;
6053		}
6054		if (ret != TRACE_TYPE_NO_CONSUME)
6055			trace_consume(iter);
6056
6057		if (trace_seq_used(&iter->seq) >= cnt)
6058			break;
6059
6060		/*
6061		 * Setting the full flag means we reached the trace_seq buffer
6062		 * size and we should leave by partial output condition above.
6063		 * One of the trace_seq_* functions is not used properly.
6064		 */
6065		WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
6066			  iter->ent->type);
6067	}
6068	trace_access_unlock(iter->cpu_file);
6069	trace_event_read_unlock();
6070
6071	/* Now copy what we have to the user */
6072	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6073	if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
6074		trace_seq_init(&iter->seq);
6075
6076	/*
6077	 * If there was nothing to send to user, in spite of consuming trace
6078	 * entries, go back to wait for more entries.
6079	 */
6080	if (sret == -EBUSY)
6081		goto waitagain;
6082
6083out:
6084	mutex_unlock(&iter->mutex);
6085
6086	return sret;
6087}
6088
6089static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
6090				     unsigned int idx)
6091{
6092	__free_page(spd->pages[idx]);
6093}
6094
6095static const struct pipe_buf_operations tracing_pipe_buf_ops = {
6096	.confirm		= generic_pipe_buf_confirm,
6097	.release		= generic_pipe_buf_release,
6098	.steal			= generic_pipe_buf_steal,
6099	.get			= generic_pipe_buf_get,
6100};
6101
6102static size_t
6103tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
6104{
6105	size_t count;
6106	int save_len;
6107	int ret;
6108
6109	/* Seq buffer is page-sized, exactly what we need. */
6110	for (;;) {
6111		save_len = iter->seq.seq.len;
6112		ret = print_trace_line(iter);
6113
6114		if (trace_seq_has_overflowed(&iter->seq)) {
6115			iter->seq.seq.len = save_len;
6116			break;
6117		}
6118
6119		/*
6120		 * This should not be hit, because it should only
6121		 * be set if the iter->seq overflowed. But check it
6122		 * anyway to be safe.
6123		 */
6124		if (ret == TRACE_TYPE_PARTIAL_LINE) {
6125			iter->seq.seq.len = save_len;
6126			break;
6127		}
6128
6129		count = trace_seq_used(&iter->seq) - save_len;
6130		if (rem < count) {
6131			rem = 0;
6132			iter->seq.seq.len = save_len;
6133			break;
6134		}
6135
6136		if (ret != TRACE_TYPE_NO_CONSUME)
6137			trace_consume(iter);
6138		rem -= count;
6139		if (!trace_find_next_entry_inc(iter))	{
6140			rem = 0;
6141			iter->ent = NULL;
6142			break;
6143		}
6144	}
6145
6146	return rem;
6147}
6148
6149static ssize_t tracing_splice_read_pipe(struct file *filp,
6150					loff_t *ppos,
6151					struct pipe_inode_info *pipe,
6152					size_t len,
6153					unsigned int flags)
6154{
6155	struct page *pages_def[PIPE_DEF_BUFFERS];
6156	struct partial_page partial_def[PIPE_DEF_BUFFERS];
6157	struct trace_iterator *iter = filp->private_data;
6158	struct splice_pipe_desc spd = {
6159		.pages		= pages_def,
6160		.partial	= partial_def,
6161		.nr_pages	= 0, /* This gets updated below. */
6162		.nr_pages_max	= PIPE_DEF_BUFFERS,
6163		.ops		= &tracing_pipe_buf_ops,
6164		.spd_release	= tracing_spd_release_pipe,
6165	};
6166	ssize_t ret;
6167	size_t rem;
6168	unsigned int i;
6169
6170	if (splice_grow_spd(pipe, &spd))
6171		return -ENOMEM;
6172
6173	mutex_lock(&iter->mutex);
6174
6175	if (iter->trace->splice_read) {
6176		ret = iter->trace->splice_read(iter, filp,
6177					       ppos, pipe, len, flags);
6178		if (ret)
6179			goto out_err;
6180	}
6181
6182	ret = tracing_wait_pipe(filp);
6183	if (ret <= 0)
6184		goto out_err;
6185
6186	if (!iter->ent && !trace_find_next_entry_inc(iter)) {
6187		ret = -EFAULT;
6188		goto out_err;
6189	}
6190
6191	trace_event_read_lock();
6192	trace_access_lock(iter->cpu_file);
6193
6194	/* Fill as many pages as possible. */
6195	for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
6196		spd.pages[i] = alloc_page(GFP_KERNEL);
6197		if (!spd.pages[i])
6198			break;
6199
6200		rem = tracing_fill_pipe_page(rem, iter);
6201
6202		/* Copy the data into the page, so we can start over. */
6203		ret = trace_seq_to_buffer(&iter->seq,
6204					  page_address(spd.pages[i]),
6205					  trace_seq_used(&iter->seq));
6206		if (ret < 0) {
6207			__free_page(spd.pages[i]);
6208			break;
6209		}
6210		spd.partial[i].offset = 0;
6211		spd.partial[i].len = trace_seq_used(&iter->seq);
6212
6213		trace_seq_init(&iter->seq);
6214	}
6215
6216	trace_access_unlock(iter->cpu_file);
6217	trace_event_read_unlock();
6218	mutex_unlock(&iter->mutex);
6219
6220	spd.nr_pages = i;
6221
6222	if (i)
6223		ret = splice_to_pipe(pipe, &spd);
6224	else
6225		ret = 0;
6226out:
6227	splice_shrink_spd(&spd);
6228	return ret;
6229
6230out_err:
6231	mutex_unlock(&iter->mutex);
6232	goto out;
6233}
6234
6235static ssize_t
6236tracing_entries_read(struct file *filp, char __user *ubuf,
6237		     size_t cnt, loff_t *ppos)
6238{
6239	struct inode *inode = file_inode(filp);
6240	struct trace_array *tr = inode->i_private;
6241	int cpu = tracing_get_cpu(inode);
6242	char buf[64];
6243	int r = 0;
6244	ssize_t ret;
6245
6246	mutex_lock(&trace_types_lock);
6247
6248	if (cpu == RING_BUFFER_ALL_CPUS) {
6249		int cpu, buf_size_same;
6250		unsigned long size;
6251
6252		size = 0;
6253		buf_size_same = 1;
6254		/* check if all cpu sizes are same */
6255		for_each_tracing_cpu(cpu) {
6256			/* fill in the size from first enabled cpu */
6257			if (size == 0)
6258				size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
6259			if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
6260				buf_size_same = 0;
6261				break;
6262			}
6263		}
6264
6265		if (buf_size_same) {
6266			if (!ring_buffer_expanded)
6267				r = sprintf(buf, "%lu (expanded: %lu)\n",
6268					    size >> 10,
6269					    trace_buf_size >> 10);
6270			else
6271				r = sprintf(buf, "%lu\n", size >> 10);
6272		} else
6273			r = sprintf(buf, "X\n");
6274	} else
6275		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
6276
6277	mutex_unlock(&trace_types_lock);
6278
6279	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6280	return ret;
6281}
6282
6283static ssize_t
6284tracing_entries_write(struct file *filp, const char __user *ubuf,
6285		      size_t cnt, loff_t *ppos)
6286{
6287	struct inode *inode = file_inode(filp);
6288	struct trace_array *tr = inode->i_private;
6289	unsigned long val;
6290	int ret;
6291
6292	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6293	if (ret)
6294		return ret;
6295
6296	/* must have at least 1 entry */
6297	if (!val)
6298		return -EINVAL;
6299
6300	/* value is in KB */
6301	val <<= 10;
6302	ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
6303	if (ret < 0)
6304		return ret;
6305
6306	*ppos += cnt;
6307
6308	return cnt;
6309}
6310
6311static ssize_t
6312tracing_total_entries_read(struct file *filp, char __user *ubuf,
6313				size_t cnt, loff_t *ppos)
6314{
6315	struct trace_array *tr = filp->private_data;
6316	char buf[64];
6317	int r, cpu;
6318	unsigned long size = 0, expanded_size = 0;
6319
6320	mutex_lock(&trace_types_lock);
6321	for_each_tracing_cpu(cpu) {
6322		size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
6323		if (!ring_buffer_expanded)
6324			expanded_size += trace_buf_size >> 10;
6325	}
6326	if (ring_buffer_expanded)
6327		r = sprintf(buf, "%lu\n", size);
6328	else
6329		r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
6330	mutex_unlock(&trace_types_lock);
6331
6332	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6333}
6334
6335static ssize_t
6336tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
6337			  size_t cnt, loff_t *ppos)
6338{
6339	/*
6340	 * There is no need to read what the user has written, this function
6341	 * is just to make sure that there is no error when "echo" is used
6342	 */
6343
6344	*ppos += cnt;
6345
6346	return cnt;
6347}
6348
6349static int
6350tracing_free_buffer_release(struct inode *inode, struct file *filp)
6351{
6352	struct trace_array *tr = inode->i_private;
6353
6354	/* disable tracing ? */
6355	if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
6356		tracer_tracing_off(tr);
6357	/* resize the ring buffer to 0 */
6358	tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
6359
6360	trace_array_put(tr);
6361
6362	return 0;
6363}
6364
6365static ssize_t
6366tracing_mark_write(struct file *filp, const char __user *ubuf,
6367					size_t cnt, loff_t *fpos)
6368{
6369	struct trace_array *tr = filp->private_data;
6370	struct ring_buffer_event *event;
6371	enum event_trigger_type tt = ETT_NONE;
6372	struct ring_buffer *buffer;
6373	struct print_entry *entry;
6374	unsigned long irq_flags;
6375	ssize_t written;
6376	int size;
6377	int len;
6378
6379/* Used in tracing_mark_raw_write() as well */
6380#define FAULTED_STR "<faulted>"
6381#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
6382
6383	if (tracing_disabled)
6384		return -EINVAL;
6385
6386	if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6387		return -EINVAL;
6388
6389	if (cnt > TRACE_BUF_SIZE)
6390		cnt = TRACE_BUF_SIZE;
6391
6392	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
6393
6394	local_save_flags(irq_flags);
6395	size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
6396
6397	/* If less than "<faulted>", then make sure we can still add that */
6398	if (cnt < FAULTED_SIZE)
6399		size += FAULTED_SIZE - cnt;
6400
6401	buffer = tr->trace_buffer.buffer;
6402	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
6403					    irq_flags, preempt_count());
6404	if (unlikely(!event))
6405		/* Ring buffer disabled, return as if not open for write */
6406		return -EBADF;
6407
6408	entry = ring_buffer_event_data(event);
6409	entry->ip = _THIS_IP_;
6410
6411	len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
6412	if (len) {
6413		memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
6414		cnt = FAULTED_SIZE;
6415		written = -EFAULT;
6416	} else
6417		written = cnt;
6418	len = cnt;
6419
6420	if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
6421		/* do not add \n before testing triggers, but add \0 */
6422		entry->buf[cnt] = '\0';
6423		tt = event_triggers_call(tr->trace_marker_file, entry, event);
6424	}
6425
6426	if (entry->buf[cnt - 1] != '\n') {
6427		entry->buf[cnt] = '\n';
6428		entry->buf[cnt + 1] = '\0';
6429	} else
6430		entry->buf[cnt] = '\0';
6431
 
 
6432	__buffer_unlock_commit(buffer, event);
6433
6434	if (tt)
6435		event_triggers_post_call(tr->trace_marker_file, tt);
6436
6437	if (written > 0)
6438		*fpos += written;
6439
6440	return written;
6441}
6442
6443/* Limit it for now to 3K (including tag) */
6444#define RAW_DATA_MAX_SIZE (1024*3)
6445
6446static ssize_t
6447tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
6448					size_t cnt, loff_t *fpos)
6449{
6450	struct trace_array *tr = filp->private_data;
6451	struct ring_buffer_event *event;
6452	struct ring_buffer *buffer;
6453	struct raw_data_entry *entry;
6454	unsigned long irq_flags;
6455	ssize_t written;
6456	int size;
6457	int len;
6458
6459#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
6460
6461	if (tracing_disabled)
6462		return -EINVAL;
6463
6464	if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6465		return -EINVAL;
6466
6467	/* The marker must at least have a tag id */
6468	if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
6469		return -EINVAL;
6470
6471	if (cnt > TRACE_BUF_SIZE)
6472		cnt = TRACE_BUF_SIZE;
6473
6474	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
6475
6476	local_save_flags(irq_flags);
6477	size = sizeof(*entry) + cnt;
6478	if (cnt < FAULT_SIZE_ID)
6479		size += FAULT_SIZE_ID - cnt;
6480
6481	buffer = tr->trace_buffer.buffer;
6482	event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
6483					    irq_flags, preempt_count());
6484	if (!event)
6485		/* Ring buffer disabled, return as if not open for write */
6486		return -EBADF;
6487
6488	entry = ring_buffer_event_data(event);
6489
6490	len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
6491	if (len) {
6492		entry->id = -1;
6493		memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
6494		written = -EFAULT;
6495	} else
6496		written = cnt;
6497
6498	__buffer_unlock_commit(buffer, event);
6499
6500	if (written > 0)
6501		*fpos += written;
6502
6503	return written;
6504}
6505
6506static int tracing_clock_show(struct seq_file *m, void *v)
6507{
6508	struct trace_array *tr = m->private;
6509	int i;
6510
6511	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
6512		seq_printf(m,
6513			"%s%s%s%s", i ? " " : "",
6514			i == tr->clock_id ? "[" : "", trace_clocks[i].name,
6515			i == tr->clock_id ? "]" : "");
6516	seq_putc(m, '\n');
6517
6518	return 0;
6519}
6520
6521int tracing_set_clock(struct trace_array *tr, const char *clockstr)
6522{
6523	int i;
6524
6525	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
6526		if (strcmp(trace_clocks[i].name, clockstr) == 0)
6527			break;
6528	}
6529	if (i == ARRAY_SIZE(trace_clocks))
6530		return -EINVAL;
6531
6532	mutex_lock(&trace_types_lock);
6533
6534	tr->clock_id = i;
6535
6536	ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
6537
6538	/*
6539	 * New clock may not be consistent with the previous clock.
6540	 * Reset the buffer so that it doesn't have incomparable timestamps.
6541	 */
6542	tracing_reset_online_cpus(&tr->trace_buffer);
6543
6544#ifdef CONFIG_TRACER_MAX_TRACE
6545	if (tr->max_buffer.buffer)
6546		ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
6547	tracing_reset_online_cpus(&tr->max_buffer);
6548#endif
6549
6550	mutex_unlock(&trace_types_lock);
6551
6552	return 0;
6553}
6554
6555static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
6556				   size_t cnt, loff_t *fpos)
6557{
6558	struct seq_file *m = filp->private_data;
6559	struct trace_array *tr = m->private;
6560	char buf[64];
6561	const char *clockstr;
6562	int ret;
6563
6564	if (cnt >= sizeof(buf))
6565		return -EINVAL;
6566
6567	if (copy_from_user(buf, ubuf, cnt))
6568		return -EFAULT;
6569
6570	buf[cnt] = 0;
6571
6572	clockstr = strstrip(buf);
6573
6574	ret = tracing_set_clock(tr, clockstr);
6575	if (ret)
6576		return ret;
6577
6578	*fpos += cnt;
6579
6580	return cnt;
6581}
6582
6583static int tracing_clock_open(struct inode *inode, struct file *file)
6584{
6585	struct trace_array *tr = inode->i_private;
6586	int ret;
6587
6588	ret = tracing_check_open_get_tr(tr);
6589	if (ret)
6590		return ret;
6591
6592	ret = single_open(file, tracing_clock_show, inode->i_private);
6593	if (ret < 0)
6594		trace_array_put(tr);
6595
6596	return ret;
6597}
6598
6599static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
6600{
6601	struct trace_array *tr = m->private;
6602
6603	mutex_lock(&trace_types_lock);
6604
6605	if (ring_buffer_time_stamp_abs(tr->trace_buffer.buffer))
6606		seq_puts(m, "delta [absolute]\n");
6607	else
6608		seq_puts(m, "[delta] absolute\n");
6609
6610	mutex_unlock(&trace_types_lock);
6611
6612	return 0;
6613}
6614
6615static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
6616{
6617	struct trace_array *tr = inode->i_private;
6618	int ret;
6619
6620	ret = tracing_check_open_get_tr(tr);
6621	if (ret)
6622		return ret;
6623
6624	ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
6625	if (ret < 0)
6626		trace_array_put(tr);
6627
6628	return ret;
6629}
6630
6631int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs)
 
 
 
 
 
 
 
 
 
 
 
6632{
6633	int ret = 0;
6634
6635	mutex_lock(&trace_types_lock);
6636
6637	if (abs && tr->time_stamp_abs_ref++)
6638		goto out;
6639
6640	if (!abs) {
6641		if (WARN_ON_ONCE(!tr->time_stamp_abs_ref)) {
6642			ret = -EINVAL;
6643			goto out;
6644		}
6645
6646		if (--tr->time_stamp_abs_ref)
6647			goto out;
6648	}
6649
6650	ring_buffer_set_time_stamp_abs(tr->trace_buffer.buffer, abs);
6651
6652#ifdef CONFIG_TRACER_MAX_TRACE
6653	if (tr->max_buffer.buffer)
6654		ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs);
6655#endif
6656 out:
6657	mutex_unlock(&trace_types_lock);
6658
6659	return ret;
6660}
6661
6662struct ftrace_buffer_info {
6663	struct trace_iterator	iter;
6664	void			*spare;
6665	unsigned int		spare_cpu;
6666	unsigned int		read;
6667};
6668
6669#ifdef CONFIG_TRACER_SNAPSHOT
6670static int tracing_snapshot_open(struct inode *inode, struct file *file)
6671{
6672	struct trace_array *tr = inode->i_private;
6673	struct trace_iterator *iter;
6674	struct seq_file *m;
6675	int ret;
6676
6677	ret = tracing_check_open_get_tr(tr);
6678	if (ret)
6679		return ret;
6680
6681	if (file->f_mode & FMODE_READ) {
6682		iter = __tracing_open(inode, file, true);
6683		if (IS_ERR(iter))
6684			ret = PTR_ERR(iter);
6685	} else {
6686		/* Writes still need the seq_file to hold the private data */
6687		ret = -ENOMEM;
6688		m = kzalloc(sizeof(*m), GFP_KERNEL);
6689		if (!m)
6690			goto out;
6691		iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6692		if (!iter) {
6693			kfree(m);
6694			goto out;
6695		}
6696		ret = 0;
6697
6698		iter->tr = tr;
6699		iter->trace_buffer = &tr->max_buffer;
6700		iter->cpu_file = tracing_get_cpu(inode);
6701		m->private = iter;
6702		file->private_data = m;
6703	}
6704out:
6705	if (ret < 0)
6706		trace_array_put(tr);
6707
6708	return ret;
6709}
6710
6711static ssize_t
6712tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
6713		       loff_t *ppos)
6714{
6715	struct seq_file *m = filp->private_data;
6716	struct trace_iterator *iter = m->private;
6717	struct trace_array *tr = iter->tr;
6718	unsigned long val;
6719	int ret;
6720
6721	ret = tracing_update_buffers();
6722	if (ret < 0)
6723		return ret;
6724
6725	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6726	if (ret)
6727		return ret;
6728
6729	mutex_lock(&trace_types_lock);
6730
6731	if (tr->current_trace->use_max_tr) {
6732		ret = -EBUSY;
6733		goto out;
6734	}
6735
6736	arch_spin_lock(&tr->max_lock);
6737	if (tr->cond_snapshot)
6738		ret = -EBUSY;
6739	arch_spin_unlock(&tr->max_lock);
6740	if (ret)
6741		goto out;
6742
6743	switch (val) {
6744	case 0:
6745		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6746			ret = -EINVAL;
6747			break;
6748		}
6749		if (tr->allocated_snapshot)
6750			free_snapshot(tr);
6751		break;
6752	case 1:
6753/* Only allow per-cpu swap if the ring buffer supports it */
6754#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
6755		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
6756			ret = -EINVAL;
6757			break;
6758		}
6759#endif
6760		if (tr->allocated_snapshot)
6761			ret = resize_buffer_duplicate_size(&tr->max_buffer,
6762					&tr->trace_buffer, iter->cpu_file);
6763		else
6764			ret = tracing_alloc_snapshot_instance(tr);
6765		if (ret < 0)
6766			break;
6767		local_irq_disable();
6768		/* Now, we're going to swap */
6769		if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6770			update_max_tr(tr, current, smp_processor_id(), NULL);
6771		else
6772			update_max_tr_single(tr, current, iter->cpu_file);
6773		local_irq_enable();
6774		break;
6775	default:
6776		if (tr->allocated_snapshot) {
6777			if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
6778				tracing_reset_online_cpus(&tr->max_buffer);
6779			else
6780				tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
6781		}
6782		break;
6783	}
6784
6785	if (ret >= 0) {
6786		*ppos += cnt;
6787		ret = cnt;
6788	}
6789out:
6790	mutex_unlock(&trace_types_lock);
6791	return ret;
6792}
6793
6794static int tracing_snapshot_release(struct inode *inode, struct file *file)
6795{
6796	struct seq_file *m = file->private_data;
6797	int ret;
6798
6799	ret = tracing_release(inode, file);
6800
6801	if (file->f_mode & FMODE_READ)
6802		return ret;
6803
6804	/* If write only, the seq_file is just a stub */
6805	if (m)
6806		kfree(m->private);
6807	kfree(m);
6808
6809	return 0;
6810}
6811
6812static int tracing_buffers_open(struct inode *inode, struct file *filp);
6813static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
6814				    size_t count, loff_t *ppos);
6815static int tracing_buffers_release(struct inode *inode, struct file *file);
6816static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
6817		   struct pipe_inode_info *pipe, size_t len, unsigned int flags);
6818
6819static int snapshot_raw_open(struct inode *inode, struct file *filp)
6820{
6821	struct ftrace_buffer_info *info;
6822	int ret;
6823
6824	/* The following checks for tracefs lockdown */
6825	ret = tracing_buffers_open(inode, filp);
6826	if (ret < 0)
6827		return ret;
6828
6829	info = filp->private_data;
6830
6831	if (info->iter.trace->use_max_tr) {
6832		tracing_buffers_release(inode, filp);
6833		return -EBUSY;
6834	}
6835
6836	info->iter.snapshot = true;
6837	info->iter.trace_buffer = &info->iter.tr->max_buffer;
6838
6839	return ret;
6840}
6841
6842#endif /* CONFIG_TRACER_SNAPSHOT */
6843
6844
6845static const struct file_operations tracing_thresh_fops = {
6846	.open		= tracing_open_generic,
6847	.read		= tracing_thresh_read,
6848	.write		= tracing_thresh_write,
6849	.llseek		= generic_file_llseek,
6850};
6851
6852#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
6853static const struct file_operations tracing_max_lat_fops = {
6854	.open		= tracing_open_generic,
6855	.read		= tracing_max_lat_read,
6856	.write		= tracing_max_lat_write,
6857	.llseek		= generic_file_llseek,
6858};
6859#endif
6860
6861static const struct file_operations set_tracer_fops = {
6862	.open		= tracing_open_generic,
6863	.read		= tracing_set_trace_read,
6864	.write		= tracing_set_trace_write,
6865	.llseek		= generic_file_llseek,
6866};
6867
6868static const struct file_operations tracing_pipe_fops = {
6869	.open		= tracing_open_pipe,
6870	.poll		= tracing_poll_pipe,
6871	.read		= tracing_read_pipe,
6872	.splice_read	= tracing_splice_read_pipe,
6873	.release	= tracing_release_pipe,
6874	.llseek		= no_llseek,
6875};
6876
6877static const struct file_operations tracing_entries_fops = {
6878	.open		= tracing_open_generic_tr,
6879	.read		= tracing_entries_read,
6880	.write		= tracing_entries_write,
6881	.llseek		= generic_file_llseek,
6882	.release	= tracing_release_generic_tr,
6883};
6884
6885static const struct file_operations tracing_total_entries_fops = {
6886	.open		= tracing_open_generic_tr,
6887	.read		= tracing_total_entries_read,
6888	.llseek		= generic_file_llseek,
6889	.release	= tracing_release_generic_tr,
6890};
6891
6892static const struct file_operations tracing_free_buffer_fops = {
6893	.open		= tracing_open_generic_tr,
6894	.write		= tracing_free_buffer_write,
6895	.release	= tracing_free_buffer_release,
6896};
6897
6898static const struct file_operations tracing_mark_fops = {
6899	.open		= tracing_open_generic_tr,
6900	.write		= tracing_mark_write,
6901	.llseek		= generic_file_llseek,
6902	.release	= tracing_release_generic_tr,
6903};
6904
6905static const struct file_operations tracing_mark_raw_fops = {
6906	.open		= tracing_open_generic_tr,
6907	.write		= tracing_mark_raw_write,
6908	.llseek		= generic_file_llseek,
6909	.release	= tracing_release_generic_tr,
6910};
6911
6912static const struct file_operations trace_clock_fops = {
6913	.open		= tracing_clock_open,
6914	.read		= seq_read,
6915	.llseek		= seq_lseek,
6916	.release	= tracing_single_release_tr,
6917	.write		= tracing_clock_write,
6918};
6919
6920static const struct file_operations trace_time_stamp_mode_fops = {
6921	.open		= tracing_time_stamp_mode_open,
6922	.read		= seq_read,
6923	.llseek		= seq_lseek,
6924	.release	= tracing_single_release_tr,
6925};
6926
6927#ifdef CONFIG_TRACER_SNAPSHOT
6928static const struct file_operations snapshot_fops = {
6929	.open		= tracing_snapshot_open,
6930	.read		= seq_read,
6931	.write		= tracing_snapshot_write,
6932	.llseek		= tracing_lseek,
6933	.release	= tracing_snapshot_release,
6934};
6935
6936static const struct file_operations snapshot_raw_fops = {
6937	.open		= snapshot_raw_open,
6938	.read		= tracing_buffers_read,
6939	.release	= tracing_buffers_release,
6940	.splice_read	= tracing_buffers_splice_read,
6941	.llseek		= no_llseek,
6942};
6943
6944#endif /* CONFIG_TRACER_SNAPSHOT */
6945
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6946#define TRACING_LOG_ERRS_MAX	8
6947#define TRACING_LOG_LOC_MAX	128
6948
6949#define CMD_PREFIX "  Command: "
6950
6951struct err_info {
6952	const char	**errs;	/* ptr to loc-specific array of err strings */
6953	u8		type;	/* index into errs -> specific err string */
6954	u8		pos;	/* MAX_FILTER_STR_VAL = 256 */
6955	u64		ts;
6956};
6957
6958struct tracing_log_err {
6959	struct list_head	list;
6960	struct err_info		info;
6961	char			loc[TRACING_LOG_LOC_MAX]; /* err location */
6962	char			cmd[MAX_FILTER_STR_VAL]; /* what caused err */
6963};
6964
6965static DEFINE_MUTEX(tracing_err_log_lock);
6966
6967static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr)
6968{
6969	struct tracing_log_err *err;
6970
6971	if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
6972		err = kzalloc(sizeof(*err), GFP_KERNEL);
6973		if (!err)
6974			err = ERR_PTR(-ENOMEM);
6975		tr->n_err_log_entries++;
6976
6977		return err;
6978	}
6979
6980	err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
6981	list_del(&err->list);
6982
6983	return err;
6984}
6985
6986/**
6987 * err_pos - find the position of a string within a command for error careting
6988 * @cmd: The tracing command that caused the error
6989 * @str: The string to position the caret at within @cmd
6990 *
6991 * Finds the position of the first occurence of @str within @cmd.  The
6992 * return value can be passed to tracing_log_err() for caret placement
6993 * within @cmd.
6994 *
6995 * Returns the index within @cmd of the first occurence of @str or 0
6996 * if @str was not found.
6997 */
6998unsigned int err_pos(char *cmd, const char *str)
6999{
7000	char *found;
7001
7002	if (WARN_ON(!strlen(cmd)))
7003		return 0;
7004
7005	found = strstr(cmd, str);
7006	if (found)
7007		return found - cmd;
7008
7009	return 0;
7010}
7011
7012/**
7013 * tracing_log_err - write an error to the tracing error log
7014 * @tr: The associated trace array for the error (NULL for top level array)
7015 * @loc: A string describing where the error occurred
7016 * @cmd: The tracing command that caused the error
7017 * @errs: The array of loc-specific static error strings
7018 * @type: The index into errs[], which produces the specific static err string
7019 * @pos: The position the caret should be placed in the cmd
7020 *
7021 * Writes an error into tracing/error_log of the form:
7022 *
7023 * <loc>: error: <text>
7024 *   Command: <cmd>
7025 *              ^
7026 *
7027 * tracing/error_log is a small log file containing the last
7028 * TRACING_LOG_ERRS_MAX errors (8).  Memory for errors isn't allocated
7029 * unless there has been a tracing error, and the error log can be
7030 * cleared and have its memory freed by writing the empty string in
7031 * truncation mode to it i.e. echo > tracing/error_log.
7032 *
7033 * NOTE: the @errs array along with the @type param are used to
7034 * produce a static error string - this string is not copied and saved
7035 * when the error is logged - only a pointer to it is saved.  See
7036 * existing callers for examples of how static strings are typically
7037 * defined for use with tracing_log_err().
7038 */
7039void tracing_log_err(struct trace_array *tr,
7040		     const char *loc, const char *cmd,
7041		     const char **errs, u8 type, u8 pos)
7042{
7043	struct tracing_log_err *err;
7044
7045	if (!tr)
7046		tr = &global_trace;
7047
7048	mutex_lock(&tracing_err_log_lock);
7049	err = get_tracing_log_err(tr);
7050	if (PTR_ERR(err) == -ENOMEM) {
7051		mutex_unlock(&tracing_err_log_lock);
7052		return;
7053	}
7054
7055	snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
7056	snprintf(err->cmd, MAX_FILTER_STR_VAL,"\n" CMD_PREFIX "%s\n", cmd);
7057
7058	err->info.errs = errs;
7059	err->info.type = type;
7060	err->info.pos = pos;
7061	err->info.ts = local_clock();
7062
7063	list_add_tail(&err->list, &tr->err_log);
7064	mutex_unlock(&tracing_err_log_lock);
7065}
7066
7067static void clear_tracing_err_log(struct trace_array *tr)
7068{
7069	struct tracing_log_err *err, *next;
7070
7071	mutex_lock(&tracing_err_log_lock);
7072	list_for_each_entry_safe(err, next, &tr->err_log, list) {
7073		list_del(&err->list);
7074		kfree(err);
7075	}
7076
7077	tr->n_err_log_entries = 0;
7078	mutex_unlock(&tracing_err_log_lock);
7079}
7080
7081static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
7082{
7083	struct trace_array *tr = m->private;
7084
7085	mutex_lock(&tracing_err_log_lock);
7086
7087	return seq_list_start(&tr->err_log, *pos);
7088}
7089
7090static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
7091{
7092	struct trace_array *tr = m->private;
7093
7094	return seq_list_next(v, &tr->err_log, pos);
7095}
7096
7097static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
7098{
7099	mutex_unlock(&tracing_err_log_lock);
7100}
7101
7102static void tracing_err_log_show_pos(struct seq_file *m, u8 pos)
7103{
7104	u8 i;
7105
7106	for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
7107		seq_putc(m, ' ');
7108	for (i = 0; i < pos; i++)
7109		seq_putc(m, ' ');
7110	seq_puts(m, "^\n");
7111}
7112
7113static int tracing_err_log_seq_show(struct seq_file *m, void *v)
7114{
7115	struct tracing_log_err *err = v;
7116
7117	if (err) {
7118		const char *err_text = err->info.errs[err->info.type];
7119		u64 sec = err->info.ts;
7120		u32 nsec;
7121
7122		nsec = do_div(sec, NSEC_PER_SEC);
7123		seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
7124			   err->loc, err_text);
7125		seq_printf(m, "%s", err->cmd);
7126		tracing_err_log_show_pos(m, err->info.pos);
7127	}
7128
7129	return 0;
7130}
7131
7132static const struct seq_operations tracing_err_log_seq_ops = {
7133	.start  = tracing_err_log_seq_start,
7134	.next   = tracing_err_log_seq_next,
7135	.stop   = tracing_err_log_seq_stop,
7136	.show   = tracing_err_log_seq_show
7137};
7138
7139static int tracing_err_log_open(struct inode *inode, struct file *file)
7140{
7141	struct trace_array *tr = inode->i_private;
7142	int ret = 0;
7143
7144	ret = tracing_check_open_get_tr(tr);
7145	if (ret)
7146		return ret;
7147
7148	/* If this file was opened for write, then erase contents */
7149	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
7150		clear_tracing_err_log(tr);
7151
7152	if (file->f_mode & FMODE_READ) {
7153		ret = seq_open(file, &tracing_err_log_seq_ops);
7154		if (!ret) {
7155			struct seq_file *m = file->private_data;
7156			m->private = tr;
7157		} else {
7158			trace_array_put(tr);
7159		}
7160	}
7161	return ret;
7162}
7163
7164static ssize_t tracing_err_log_write(struct file *file,
7165				     const char __user *buffer,
7166				     size_t count, loff_t *ppos)
7167{
7168	return count;
7169}
7170
7171static int tracing_err_log_release(struct inode *inode, struct file *file)
7172{
7173	struct trace_array *tr = inode->i_private;
7174
7175	trace_array_put(tr);
7176
7177	if (file->f_mode & FMODE_READ)
7178		seq_release(inode, file);
7179
7180	return 0;
7181}
7182
7183static const struct file_operations tracing_err_log_fops = {
7184	.open           = tracing_err_log_open,
7185	.write		= tracing_err_log_write,
7186	.read           = seq_read,
7187	.llseek         = seq_lseek,
7188	.release        = tracing_err_log_release,
7189};
7190
7191static int tracing_buffers_open(struct inode *inode, struct file *filp)
7192{
7193	struct trace_array *tr = inode->i_private;
7194	struct ftrace_buffer_info *info;
7195	int ret;
7196
7197	ret = tracing_check_open_get_tr(tr);
7198	if (ret)
7199		return ret;
7200
7201	info = kzalloc(sizeof(*info), GFP_KERNEL);
7202	if (!info) {
7203		trace_array_put(tr);
7204		return -ENOMEM;
7205	}
7206
7207	mutex_lock(&trace_types_lock);
7208
7209	info->iter.tr		= tr;
7210	info->iter.cpu_file	= tracing_get_cpu(inode);
7211	info->iter.trace	= tr->current_trace;
7212	info->iter.trace_buffer = &tr->trace_buffer;
7213	info->spare		= NULL;
7214	/* Force reading ring buffer for first read */
7215	info->read		= (unsigned int)-1;
7216
7217	filp->private_data = info;
7218
7219	tr->current_trace->ref++;
7220
7221	mutex_unlock(&trace_types_lock);
7222
7223	ret = nonseekable_open(inode, filp);
7224	if (ret < 0)
7225		trace_array_put(tr);
7226
7227	return ret;
7228}
7229
7230static __poll_t
7231tracing_buffers_poll(struct file *filp, poll_table *poll_table)
7232{
7233	struct ftrace_buffer_info *info = filp->private_data;
7234	struct trace_iterator *iter = &info->iter;
7235
7236	return trace_poll(iter, filp, poll_table);
7237}
7238
7239static ssize_t
7240tracing_buffers_read(struct file *filp, char __user *ubuf,
7241		     size_t count, loff_t *ppos)
7242{
7243	struct ftrace_buffer_info *info = filp->private_data;
7244	struct trace_iterator *iter = &info->iter;
7245	ssize_t ret = 0;
7246	ssize_t size;
7247
7248	if (!count)
7249		return 0;
7250
7251#ifdef CONFIG_TRACER_MAX_TRACE
7252	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
7253		return -EBUSY;
7254#endif
7255
7256	if (!info->spare) {
7257		info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
7258							  iter->cpu_file);
7259		if (IS_ERR(info->spare)) {
7260			ret = PTR_ERR(info->spare);
7261			info->spare = NULL;
7262		} else {
7263			info->spare_cpu = iter->cpu_file;
7264		}
7265	}
7266	if (!info->spare)
7267		return ret;
7268
7269	/* Do we have previous read data to read? */
7270	if (info->read < PAGE_SIZE)
7271		goto read;
7272
7273 again:
7274	trace_access_lock(iter->cpu_file);
7275	ret = ring_buffer_read_page(iter->trace_buffer->buffer,
7276				    &info->spare,
7277				    count,
7278				    iter->cpu_file, 0);
7279	trace_access_unlock(iter->cpu_file);
7280
7281	if (ret < 0) {
7282		if (trace_empty(iter)) {
7283			if ((filp->f_flags & O_NONBLOCK))
7284				return -EAGAIN;
7285
7286			ret = wait_on_pipe(iter, 0);
7287			if (ret)
7288				return ret;
7289
7290			goto again;
7291		}
7292		return 0;
7293	}
7294
7295	info->read = 0;
7296 read:
7297	size = PAGE_SIZE - info->read;
7298	if (size > count)
7299		size = count;
7300
7301	ret = copy_to_user(ubuf, info->spare + info->read, size);
7302	if (ret == size)
7303		return -EFAULT;
7304
7305	size -= ret;
7306
7307	*ppos += size;
7308	info->read += size;
7309
7310	return size;
7311}
7312
7313static int tracing_buffers_release(struct inode *inode, struct file *file)
7314{
7315	struct ftrace_buffer_info *info = file->private_data;
7316	struct trace_iterator *iter = &info->iter;
7317
7318	mutex_lock(&trace_types_lock);
7319
7320	iter->tr->current_trace->ref--;
7321
7322	__trace_array_put(iter->tr);
7323
7324	if (info->spare)
7325		ring_buffer_free_read_page(iter->trace_buffer->buffer,
7326					   info->spare_cpu, info->spare);
7327	kfree(info);
7328
7329	mutex_unlock(&trace_types_lock);
7330
7331	return 0;
7332}
7333
7334struct buffer_ref {
7335	struct ring_buffer	*buffer;
7336	void			*page;
7337	int			cpu;
7338	refcount_t		refcount;
7339};
7340
7341static void buffer_ref_release(struct buffer_ref *ref)
7342{
7343	if (!refcount_dec_and_test(&ref->refcount))
7344		return;
7345	ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
7346	kfree(ref);
7347}
7348
7349static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
7350				    struct pipe_buffer *buf)
7351{
7352	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
7353
7354	buffer_ref_release(ref);
7355	buf->private = 0;
7356}
7357
7358static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
7359				struct pipe_buffer *buf)
7360{
7361	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
7362
7363	if (refcount_read(&ref->refcount) > INT_MAX/2)
7364		return false;
7365
7366	refcount_inc(&ref->refcount);
7367	return true;
7368}
7369
7370/* Pipe buffer operations for a buffer. */
7371static const struct pipe_buf_operations buffer_pipe_buf_ops = {
7372	.confirm		= generic_pipe_buf_confirm,
7373	.release		= buffer_pipe_buf_release,
7374	.steal			= generic_pipe_buf_nosteal,
7375	.get			= buffer_pipe_buf_get,
7376};
7377
7378/*
7379 * Callback from splice_to_pipe(), if we need to release some pages
7380 * at the end of the spd in case we error'ed out in filling the pipe.
7381 */
7382static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
7383{
7384	struct buffer_ref *ref =
7385		(struct buffer_ref *)spd->partial[i].private;
7386
7387	buffer_ref_release(ref);
7388	spd->partial[i].private = 0;
7389}
7390
7391static ssize_t
7392tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7393			    struct pipe_inode_info *pipe, size_t len,
7394			    unsigned int flags)
7395{
7396	struct ftrace_buffer_info *info = file->private_data;
7397	struct trace_iterator *iter = &info->iter;
7398	struct partial_page partial_def[PIPE_DEF_BUFFERS];
7399	struct page *pages_def[PIPE_DEF_BUFFERS];
7400	struct splice_pipe_desc spd = {
7401		.pages		= pages_def,
7402		.partial	= partial_def,
7403		.nr_pages_max	= PIPE_DEF_BUFFERS,
7404		.ops		= &buffer_pipe_buf_ops,
7405		.spd_release	= buffer_spd_release,
7406	};
7407	struct buffer_ref *ref;
7408	int entries, i;
7409	ssize_t ret = 0;
7410
7411#ifdef CONFIG_TRACER_MAX_TRACE
7412	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
7413		return -EBUSY;
7414#endif
7415
7416	if (*ppos & (PAGE_SIZE - 1))
7417		return -EINVAL;
7418
7419	if (len & (PAGE_SIZE - 1)) {
7420		if (len < PAGE_SIZE)
7421			return -EINVAL;
7422		len &= PAGE_MASK;
7423	}
7424
7425	if (splice_grow_spd(pipe, &spd))
7426		return -ENOMEM;
7427
7428 again:
7429	trace_access_lock(iter->cpu_file);
7430	entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
7431
7432	for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
7433		struct page *page;
7434		int r;
7435
7436		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
7437		if (!ref) {
7438			ret = -ENOMEM;
7439			break;
7440		}
7441
7442		refcount_set(&ref->refcount, 1);
7443		ref->buffer = iter->trace_buffer->buffer;
7444		ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
7445		if (IS_ERR(ref->page)) {
7446			ret = PTR_ERR(ref->page);
7447			ref->page = NULL;
7448			kfree(ref);
7449			break;
7450		}
7451		ref->cpu = iter->cpu_file;
7452
7453		r = ring_buffer_read_page(ref->buffer, &ref->page,
7454					  len, iter->cpu_file, 1);
7455		if (r < 0) {
7456			ring_buffer_free_read_page(ref->buffer, ref->cpu,
7457						   ref->page);
7458			kfree(ref);
7459			break;
7460		}
7461
7462		page = virt_to_page(ref->page);
7463
7464		spd.pages[i] = page;
7465		spd.partial[i].len = PAGE_SIZE;
7466		spd.partial[i].offset = 0;
7467		spd.partial[i].private = (unsigned long)ref;
7468		spd.nr_pages++;
7469		*ppos += PAGE_SIZE;
7470
7471		entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
7472	}
7473
7474	trace_access_unlock(iter->cpu_file);
7475	spd.nr_pages = i;
7476
7477	/* did we read anything? */
7478	if (!spd.nr_pages) {
7479		if (ret)
7480			goto out;
7481
7482		ret = -EAGAIN;
7483		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
7484			goto out;
7485
7486		ret = wait_on_pipe(iter, iter->tr->buffer_percent);
7487		if (ret)
7488			goto out;
7489
7490		goto again;
7491	}
7492
7493	ret = splice_to_pipe(pipe, &spd);
7494out:
7495	splice_shrink_spd(&spd);
7496
7497	return ret;
7498}
7499
7500static const struct file_operations tracing_buffers_fops = {
7501	.open		= tracing_buffers_open,
7502	.read		= tracing_buffers_read,
7503	.poll		= tracing_buffers_poll,
7504	.release	= tracing_buffers_release,
7505	.splice_read	= tracing_buffers_splice_read,
7506	.llseek		= no_llseek,
7507};
7508
7509static ssize_t
7510tracing_stats_read(struct file *filp, char __user *ubuf,
7511		   size_t count, loff_t *ppos)
7512{
7513	struct inode *inode = file_inode(filp);
7514	struct trace_array *tr = inode->i_private;
7515	struct trace_buffer *trace_buf = &tr->trace_buffer;
7516	int cpu = tracing_get_cpu(inode);
7517	struct trace_seq *s;
7518	unsigned long cnt;
7519	unsigned long long t;
7520	unsigned long usec_rem;
7521
7522	s = kmalloc(sizeof(*s), GFP_KERNEL);
7523	if (!s)
7524		return -ENOMEM;
7525
7526	trace_seq_init(s);
7527
7528	cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
7529	trace_seq_printf(s, "entries: %ld\n", cnt);
7530
7531	cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
7532	trace_seq_printf(s, "overrun: %ld\n", cnt);
7533
7534	cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
7535	trace_seq_printf(s, "commit overrun: %ld\n", cnt);
7536
7537	cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
7538	trace_seq_printf(s, "bytes: %ld\n", cnt);
7539
7540	if (trace_clocks[tr->clock_id].in_ns) {
7541		/* local or global for trace_clock */
7542		t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
7543		usec_rem = do_div(t, USEC_PER_SEC);
7544		trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
7545								t, usec_rem);
7546
7547		t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
7548		usec_rem = do_div(t, USEC_PER_SEC);
7549		trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
7550	} else {
7551		/* counter or tsc mode for trace_clock */
7552		trace_seq_printf(s, "oldest event ts: %llu\n",
7553				ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
7554
7555		trace_seq_printf(s, "now ts: %llu\n",
7556				ring_buffer_time_stamp(trace_buf->buffer, cpu));
7557	}
7558
7559	cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
7560	trace_seq_printf(s, "dropped events: %ld\n", cnt);
7561
7562	cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
7563	trace_seq_printf(s, "read events: %ld\n", cnt);
7564
7565	count = simple_read_from_buffer(ubuf, count, ppos,
7566					s->buffer, trace_seq_used(s));
7567
7568	kfree(s);
7569
7570	return count;
7571}
7572
7573static const struct file_operations tracing_stats_fops = {
7574	.open		= tracing_open_generic_tr,
7575	.read		= tracing_stats_read,
7576	.llseek		= generic_file_llseek,
7577	.release	= tracing_release_generic_tr,
7578};
7579
7580#ifdef CONFIG_DYNAMIC_FTRACE
7581
7582static ssize_t
7583tracing_read_dyn_info(struct file *filp, char __user *ubuf,
7584		  size_t cnt, loff_t *ppos)
7585{
7586	unsigned long *p = filp->private_data;
7587	char buf[64]; /* Not too big for a shallow stack */
7588	int r;
7589
7590	r = scnprintf(buf, 63, "%ld", *p);
7591	buf[r++] = '\n';
 
 
7592
7593	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 
 
 
 
 
 
 
7594}
7595
7596static const struct file_operations tracing_dyn_info_fops = {
7597	.open		= tracing_open_generic,
7598	.read		= tracing_read_dyn_info,
7599	.llseek		= generic_file_llseek,
7600};
7601#endif /* CONFIG_DYNAMIC_FTRACE */
7602
7603#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
7604static void
7605ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
7606		struct trace_array *tr, struct ftrace_probe_ops *ops,
7607		void *data)
7608{
7609	tracing_snapshot_instance(tr);
7610}
7611
7612static void
7613ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
7614		      struct trace_array *tr, struct ftrace_probe_ops *ops,
7615		      void *data)
7616{
7617	struct ftrace_func_mapper *mapper = data;
7618	long *count = NULL;
7619
7620	if (mapper)
7621		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
7622
7623	if (count) {
7624
7625		if (*count <= 0)
7626			return;
7627
7628		(*count)--;
7629	}
7630
7631	tracing_snapshot_instance(tr);
7632}
7633
7634static int
7635ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
7636		      struct ftrace_probe_ops *ops, void *data)
7637{
7638	struct ftrace_func_mapper *mapper = data;
7639	long *count = NULL;
7640
7641	seq_printf(m, "%ps:", (void *)ip);
7642
7643	seq_puts(m, "snapshot");
7644
7645	if (mapper)
7646		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
7647
7648	if (count)
7649		seq_printf(m, ":count=%ld\n", *count);
7650	else
7651		seq_puts(m, ":unlimited\n");
7652
7653	return 0;
7654}
7655
7656static int
7657ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
7658		     unsigned long ip, void *init_data, void **data)
7659{
7660	struct ftrace_func_mapper *mapper = *data;
7661
7662	if (!mapper) {
7663		mapper = allocate_ftrace_func_mapper();
7664		if (!mapper)
7665			return -ENOMEM;
7666		*data = mapper;
7667	}
7668
7669	return ftrace_func_mapper_add_ip(mapper, ip, init_data);
7670}
7671
7672static void
7673ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
7674		     unsigned long ip, void *data)
7675{
7676	struct ftrace_func_mapper *mapper = data;
7677
7678	if (!ip) {
7679		if (!mapper)
7680			return;
7681		free_ftrace_func_mapper(mapper, NULL);
7682		return;
7683	}
7684
7685	ftrace_func_mapper_remove_ip(mapper, ip);
7686}
7687
7688static struct ftrace_probe_ops snapshot_probe_ops = {
7689	.func			= ftrace_snapshot,
7690	.print			= ftrace_snapshot_print,
7691};
7692
7693static struct ftrace_probe_ops snapshot_count_probe_ops = {
7694	.func			= ftrace_count_snapshot,
7695	.print			= ftrace_snapshot_print,
7696	.init			= ftrace_snapshot_init,
7697	.free			= ftrace_snapshot_free,
7698};
7699
7700static int
7701ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
7702			       char *glob, char *cmd, char *param, int enable)
7703{
7704	struct ftrace_probe_ops *ops;
7705	void *count = (void *)-1;
7706	char *number;
7707	int ret;
7708
7709	if (!tr)
7710		return -ENODEV;
7711
7712	/* hash funcs only work with set_ftrace_filter */
7713	if (!enable)
7714		return -EINVAL;
7715
7716	ops = param ? &snapshot_count_probe_ops :  &snapshot_probe_ops;
7717
7718	if (glob[0] == '!')
7719		return unregister_ftrace_function_probe_func(glob+1, tr, ops);
7720
7721	if (!param)
7722		goto out_reg;
7723
7724	number = strsep(&param, ":");
7725
7726	if (!strlen(number))
7727		goto out_reg;
7728
7729	/*
7730	 * We use the callback data field (which is a pointer)
7731	 * as our counter.
7732	 */
7733	ret = kstrtoul(number, 0, (unsigned long *)&count);
7734	if (ret)
7735		return ret;
7736
7737 out_reg:
7738	ret = tracing_alloc_snapshot_instance(tr);
7739	if (ret < 0)
7740		goto out;
7741
7742	ret = register_ftrace_function_probe(glob, tr, ops, count);
7743
7744 out:
7745	return ret < 0 ? ret : 0;
7746}
7747
7748static struct ftrace_func_command ftrace_snapshot_cmd = {
7749	.name			= "snapshot",
7750	.func			= ftrace_trace_snapshot_callback,
7751};
7752
7753static __init int register_snapshot_cmd(void)
7754{
7755	return register_ftrace_command(&ftrace_snapshot_cmd);
7756}
7757#else
7758static inline __init int register_snapshot_cmd(void) { return 0; }
7759#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
7760
7761static struct dentry *tracing_get_dentry(struct trace_array *tr)
7762{
7763	if (WARN_ON(!tr->dir))
7764		return ERR_PTR(-ENODEV);
7765
7766	/* Top directory uses NULL as the parent */
7767	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
7768		return NULL;
7769
7770	/* All sub buffers have a descriptor */
7771	return tr->dir;
7772}
7773
7774static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
7775{
7776	struct dentry *d_tracer;
7777
7778	if (tr->percpu_dir)
7779		return tr->percpu_dir;
7780
7781	d_tracer = tracing_get_dentry(tr);
7782	if (IS_ERR(d_tracer))
7783		return NULL;
7784
7785	tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
7786
7787	WARN_ONCE(!tr->percpu_dir,
7788		  "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
7789
7790	return tr->percpu_dir;
7791}
7792
7793static struct dentry *
7794trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
7795		      void *data, long cpu, const struct file_operations *fops)
7796{
7797	struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
7798
7799	if (ret) /* See tracing_get_cpu() */
7800		d_inode(ret)->i_cdev = (void *)(cpu + 1);
7801	return ret;
7802}
7803
7804static void
7805tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
7806{
7807	struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
7808	struct dentry *d_cpu;
7809	char cpu_dir[30]; /* 30 characters should be more than enough */
7810
7811	if (!d_percpu)
7812		return;
7813
7814	snprintf(cpu_dir, 30, "cpu%ld", cpu);
7815	d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
7816	if (!d_cpu) {
7817		pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
7818		return;
7819	}
7820
7821	/* per cpu trace_pipe */
7822	trace_create_cpu_file("trace_pipe", 0444, d_cpu,
7823				tr, cpu, &tracing_pipe_fops);
7824
7825	/* per cpu trace */
7826	trace_create_cpu_file("trace", 0644, d_cpu,
7827				tr, cpu, &tracing_fops);
7828
7829	trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
7830				tr, cpu, &tracing_buffers_fops);
7831
7832	trace_create_cpu_file("stats", 0444, d_cpu,
7833				tr, cpu, &tracing_stats_fops);
7834
7835	trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
7836				tr, cpu, &tracing_entries_fops);
7837
7838#ifdef CONFIG_TRACER_SNAPSHOT
7839	trace_create_cpu_file("snapshot", 0644, d_cpu,
7840				tr, cpu, &snapshot_fops);
7841
7842	trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
7843				tr, cpu, &snapshot_raw_fops);
7844#endif
7845}
7846
7847#ifdef CONFIG_FTRACE_SELFTEST
7848/* Let selftest have access to static functions in this file */
7849#include "trace_selftest.c"
7850#endif
7851
7852static ssize_t
7853trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
7854			loff_t *ppos)
7855{
7856	struct trace_option_dentry *topt = filp->private_data;
7857	char *buf;
7858
7859	if (topt->flags->val & topt->opt->bit)
7860		buf = "1\n";
7861	else
7862		buf = "0\n";
7863
7864	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
7865}
7866
7867static ssize_t
7868trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
7869			 loff_t *ppos)
7870{
7871	struct trace_option_dentry *topt = filp->private_data;
7872	unsigned long val;
7873	int ret;
7874
7875	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7876	if (ret)
7877		return ret;
7878
7879	if (val != 0 && val != 1)
7880		return -EINVAL;
7881
7882	if (!!(topt->flags->val & topt->opt->bit) != val) {
7883		mutex_lock(&trace_types_lock);
7884		ret = __set_tracer_option(topt->tr, topt->flags,
7885					  topt->opt, !val);
7886		mutex_unlock(&trace_types_lock);
7887		if (ret)
7888			return ret;
7889	}
7890
7891	*ppos += cnt;
7892
7893	return cnt;
7894}
7895
7896
7897static const struct file_operations trace_options_fops = {
7898	.open = tracing_open_generic,
7899	.read = trace_options_read,
7900	.write = trace_options_write,
7901	.llseek	= generic_file_llseek,
7902};
7903
7904/*
7905 * In order to pass in both the trace_array descriptor as well as the index
7906 * to the flag that the trace option file represents, the trace_array
7907 * has a character array of trace_flags_index[], which holds the index
7908 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
7909 * The address of this character array is passed to the flag option file
7910 * read/write callbacks.
7911 *
7912 * In order to extract both the index and the trace_array descriptor,
7913 * get_tr_index() uses the following algorithm.
7914 *
7915 *   idx = *ptr;
7916 *
7917 * As the pointer itself contains the address of the index (remember
7918 * index[1] == 1).
7919 *
7920 * Then to get the trace_array descriptor, by subtracting that index
7921 * from the ptr, we get to the start of the index itself.
7922 *
7923 *   ptr - idx == &index[0]
7924 *
7925 * Then a simple container_of() from that pointer gets us to the
7926 * trace_array descriptor.
7927 */
7928static void get_tr_index(void *data, struct trace_array **ptr,
7929			 unsigned int *pindex)
7930{
7931	*pindex = *(unsigned char *)data;
7932
7933	*ptr = container_of(data - *pindex, struct trace_array,
7934			    trace_flags_index);
7935}
7936
7937static ssize_t
7938trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
7939			loff_t *ppos)
7940{
7941	void *tr_index = filp->private_data;
7942	struct trace_array *tr;
7943	unsigned int index;
7944	char *buf;
7945
7946	get_tr_index(tr_index, &tr, &index);
7947
7948	if (tr->trace_flags & (1 << index))
7949		buf = "1\n";
7950	else
7951		buf = "0\n";
7952
7953	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
7954}
7955
7956static ssize_t
7957trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
7958			 loff_t *ppos)
7959{
7960	void *tr_index = filp->private_data;
7961	struct trace_array *tr;
7962	unsigned int index;
7963	unsigned long val;
7964	int ret;
7965
7966	get_tr_index(tr_index, &tr, &index);
7967
7968	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7969	if (ret)
7970		return ret;
7971
7972	if (val != 0 && val != 1)
7973		return -EINVAL;
7974
 
7975	mutex_lock(&trace_types_lock);
7976	ret = set_tracer_flag(tr, 1 << index, val);
7977	mutex_unlock(&trace_types_lock);
 
7978
7979	if (ret < 0)
7980		return ret;
7981
7982	*ppos += cnt;
7983
7984	return cnt;
7985}
7986
7987static const struct file_operations trace_options_core_fops = {
7988	.open = tracing_open_generic,
7989	.read = trace_options_core_read,
7990	.write = trace_options_core_write,
7991	.llseek = generic_file_llseek,
7992};
7993
7994struct dentry *trace_create_file(const char *name,
7995				 umode_t mode,
7996				 struct dentry *parent,
7997				 void *data,
7998				 const struct file_operations *fops)
7999{
8000	struct dentry *ret;
8001
8002	ret = tracefs_create_file(name, mode, parent, data, fops);
8003	if (!ret)
8004		pr_warn("Could not create tracefs '%s' entry\n", name);
8005
8006	return ret;
8007}
8008
8009
8010static struct dentry *trace_options_init_dentry(struct trace_array *tr)
8011{
8012	struct dentry *d_tracer;
8013
8014	if (tr->options)
8015		return tr->options;
8016
8017	d_tracer = tracing_get_dentry(tr);
8018	if (IS_ERR(d_tracer))
8019		return NULL;
8020
8021	tr->options = tracefs_create_dir("options", d_tracer);
8022	if (!tr->options) {
8023		pr_warn("Could not create tracefs directory 'options'\n");
8024		return NULL;
8025	}
8026
8027	return tr->options;
8028}
8029
8030static void
8031create_trace_option_file(struct trace_array *tr,
8032			 struct trace_option_dentry *topt,
8033			 struct tracer_flags *flags,
8034			 struct tracer_opt *opt)
8035{
8036	struct dentry *t_options;
8037
8038	t_options = trace_options_init_dentry(tr);
8039	if (!t_options)
8040		return;
8041
8042	topt->flags = flags;
8043	topt->opt = opt;
8044	topt->tr = tr;
8045
8046	topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
8047				    &trace_options_fops);
8048
8049}
8050
8051static void
8052create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
8053{
8054	struct trace_option_dentry *topts;
8055	struct trace_options *tr_topts;
8056	struct tracer_flags *flags;
8057	struct tracer_opt *opts;
8058	int cnt;
8059	int i;
8060
8061	if (!tracer)
8062		return;
8063
8064	flags = tracer->flags;
8065
8066	if (!flags || !flags->opts)
8067		return;
8068
8069	/*
8070	 * If this is an instance, only create flags for tracers
8071	 * the instance may have.
8072	 */
8073	if (!trace_ok_for_array(tracer, tr))
8074		return;
8075
8076	for (i = 0; i < tr->nr_topts; i++) {
8077		/* Make sure there's no duplicate flags. */
8078		if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
8079			return;
8080	}
8081
8082	opts = flags->opts;
8083
8084	for (cnt = 0; opts[cnt].name; cnt++)
8085		;
8086
8087	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
8088	if (!topts)
8089		return;
8090
8091	tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
8092			    GFP_KERNEL);
8093	if (!tr_topts) {
8094		kfree(topts);
8095		return;
8096	}
8097
8098	tr->topts = tr_topts;
8099	tr->topts[tr->nr_topts].tracer = tracer;
8100	tr->topts[tr->nr_topts].topts = topts;
8101	tr->nr_topts++;
8102
8103	for (cnt = 0; opts[cnt].name; cnt++) {
8104		create_trace_option_file(tr, &topts[cnt], flags,
8105					 &opts[cnt]);
8106		WARN_ONCE(topts[cnt].entry == NULL,
8107			  "Failed to create trace option: %s",
8108			  opts[cnt].name);
8109	}
8110}
8111
8112static struct dentry *
8113create_trace_option_core_file(struct trace_array *tr,
8114			      const char *option, long index)
8115{
8116	struct dentry *t_options;
8117
8118	t_options = trace_options_init_dentry(tr);
8119	if (!t_options)
8120		return NULL;
8121
8122	return trace_create_file(option, 0644, t_options,
8123				 (void *)&tr->trace_flags_index[index],
8124				 &trace_options_core_fops);
8125}
8126
8127static void create_trace_options_dir(struct trace_array *tr)
8128{
8129	struct dentry *t_options;
8130	bool top_level = tr == &global_trace;
8131	int i;
8132
8133	t_options = trace_options_init_dentry(tr);
8134	if (!t_options)
8135		return;
8136
8137	for (i = 0; trace_options[i]; i++) {
8138		if (top_level ||
8139		    !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
8140			create_trace_option_core_file(tr, trace_options[i], i);
8141	}
8142}
8143
8144static ssize_t
8145rb_simple_read(struct file *filp, char __user *ubuf,
8146	       size_t cnt, loff_t *ppos)
8147{
8148	struct trace_array *tr = filp->private_data;
8149	char buf[64];
8150	int r;
8151
8152	r = tracer_tracing_is_on(tr);
8153	r = sprintf(buf, "%d\n", r);
8154
8155	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8156}
8157
8158static ssize_t
8159rb_simple_write(struct file *filp, const char __user *ubuf,
8160		size_t cnt, loff_t *ppos)
8161{
8162	struct trace_array *tr = filp->private_data;
8163	struct ring_buffer *buffer = tr->trace_buffer.buffer;
8164	unsigned long val;
8165	int ret;
8166
8167	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8168	if (ret)
8169		return ret;
8170
8171	if (buffer) {
8172		mutex_lock(&trace_types_lock);
8173		if (!!val == tracer_tracing_is_on(tr)) {
8174			val = 0; /* do nothing */
8175		} else if (val) {
8176			tracer_tracing_on(tr);
8177			if (tr->current_trace->start)
8178				tr->current_trace->start(tr);
8179		} else {
8180			tracer_tracing_off(tr);
8181			if (tr->current_trace->stop)
8182				tr->current_trace->stop(tr);
8183		}
8184		mutex_unlock(&trace_types_lock);
8185	}
8186
8187	(*ppos)++;
8188
8189	return cnt;
8190}
8191
8192static const struct file_operations rb_simple_fops = {
8193	.open		= tracing_open_generic_tr,
8194	.read		= rb_simple_read,
8195	.write		= rb_simple_write,
8196	.release	= tracing_release_generic_tr,
8197	.llseek		= default_llseek,
8198};
8199
8200static ssize_t
8201buffer_percent_read(struct file *filp, char __user *ubuf,
8202		    size_t cnt, loff_t *ppos)
8203{
8204	struct trace_array *tr = filp->private_data;
8205	char buf[64];
8206	int r;
8207
8208	r = tr->buffer_percent;
8209	r = sprintf(buf, "%d\n", r);
8210
8211	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8212}
8213
8214static ssize_t
8215buffer_percent_write(struct file *filp, const char __user *ubuf,
8216		     size_t cnt, loff_t *ppos)
8217{
8218	struct trace_array *tr = filp->private_data;
8219	unsigned long val;
8220	int ret;
8221
8222	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8223	if (ret)
8224		return ret;
8225
8226	if (val > 100)
8227		return -EINVAL;
8228
8229	if (!val)
8230		val = 1;
8231
8232	tr->buffer_percent = val;
8233
8234	(*ppos)++;
8235
8236	return cnt;
8237}
8238
8239static const struct file_operations buffer_percent_fops = {
8240	.open		= tracing_open_generic_tr,
8241	.read		= buffer_percent_read,
8242	.write		= buffer_percent_write,
8243	.release	= tracing_release_generic_tr,
8244	.llseek		= default_llseek,
8245};
8246
8247static struct dentry *trace_instance_dir;
8248
8249static void
8250init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
8251
8252static int
8253allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
8254{
8255	enum ring_buffer_flags rb_flags;
8256
8257	rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
8258
8259	buf->tr = tr;
8260
8261	buf->buffer = ring_buffer_alloc(size, rb_flags);
8262	if (!buf->buffer)
8263		return -ENOMEM;
8264
8265	buf->data = alloc_percpu(struct trace_array_cpu);
8266	if (!buf->data) {
8267		ring_buffer_free(buf->buffer);
8268		buf->buffer = NULL;
8269		return -ENOMEM;
8270	}
8271
8272	/* Allocate the first page for all buffers */
8273	set_buffer_entries(&tr->trace_buffer,
8274			   ring_buffer_size(tr->trace_buffer.buffer, 0));
8275
8276	return 0;
8277}
8278
8279static int allocate_trace_buffers(struct trace_array *tr, int size)
8280{
8281	int ret;
8282
8283	ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
8284	if (ret)
8285		return ret;
8286
8287#ifdef CONFIG_TRACER_MAX_TRACE
8288	ret = allocate_trace_buffer(tr, &tr->max_buffer,
8289				    allocate_snapshot ? size : 1);
8290	if (WARN_ON(ret)) {
8291		ring_buffer_free(tr->trace_buffer.buffer);
8292		tr->trace_buffer.buffer = NULL;
8293		free_percpu(tr->trace_buffer.data);
8294		tr->trace_buffer.data = NULL;
8295		return -ENOMEM;
8296	}
8297	tr->allocated_snapshot = allocate_snapshot;
8298
8299	/*
8300	 * Only the top level trace array gets its snapshot allocated
8301	 * from the kernel command line.
8302	 */
8303	allocate_snapshot = false;
8304#endif
 
8305	return 0;
8306}
8307
8308static void free_trace_buffer(struct trace_buffer *buf)
8309{
8310	if (buf->buffer) {
8311		ring_buffer_free(buf->buffer);
8312		buf->buffer = NULL;
8313		free_percpu(buf->data);
8314		buf->data = NULL;
8315	}
8316}
8317
8318static void free_trace_buffers(struct trace_array *tr)
8319{
8320	if (!tr)
8321		return;
8322
8323	free_trace_buffer(&tr->trace_buffer);
8324
8325#ifdef CONFIG_TRACER_MAX_TRACE
8326	free_trace_buffer(&tr->max_buffer);
8327#endif
8328}
8329
8330static void init_trace_flags_index(struct trace_array *tr)
8331{
8332	int i;
8333
8334	/* Used by the trace options files */
8335	for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
8336		tr->trace_flags_index[i] = i;
8337}
8338
8339static void __update_tracer_options(struct trace_array *tr)
8340{
8341	struct tracer *t;
8342
8343	for (t = trace_types; t; t = t->next)
8344		add_tracer_options(tr, t);
8345}
8346
8347static void update_tracer_options(struct trace_array *tr)
8348{
8349	mutex_lock(&trace_types_lock);
8350	__update_tracer_options(tr);
8351	mutex_unlock(&trace_types_lock);
8352}
8353
8354struct trace_array *trace_array_create(const char *name)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8355{
8356	struct trace_array *tr;
8357	int ret;
8358
8359	mutex_lock(&event_mutex);
8360	mutex_lock(&trace_types_lock);
 
 
 
 
8361
8362	ret = -EEXIST;
8363	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
8364		if (tr->name && strcmp(tr->name, name) == 0)
8365			goto out_unlock;
 
 
 
 
 
 
 
 
 
 
 
8366	}
8367
 
 
 
 
 
 
 
 
 
 
 
8368	ret = -ENOMEM;
8369	tr = kzalloc(sizeof(*tr), GFP_KERNEL);
8370	if (!tr)
8371		goto out_unlock;
8372
8373	tr->name = kstrdup(name, GFP_KERNEL);
8374	if (!tr->name)
8375		goto out_free_tr;
8376
8377	if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
8378		goto out_free_tr;
8379
8380	tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
8381
8382	cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
8383
8384	raw_spin_lock_init(&tr->start_lock);
8385
8386	tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
8387
8388	tr->current_trace = &nop_trace;
8389
8390	INIT_LIST_HEAD(&tr->systems);
8391	INIT_LIST_HEAD(&tr->events);
8392	INIT_LIST_HEAD(&tr->hist_vars);
8393	INIT_LIST_HEAD(&tr->err_log);
8394
8395	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
8396		goto out_free_tr;
8397
8398	tr->dir = tracefs_create_dir(name, trace_instance_dir);
8399	if (!tr->dir)
8400		goto out_free_tr;
8401
8402	ret = event_trace_add_tracer(tr->dir, tr);
8403	if (ret) {
8404		tracefs_remove_recursive(tr->dir);
8405		goto out_free_tr;
8406	}
8407
8408	ftrace_init_trace_array(tr);
8409
8410	init_tracer_tracefs(tr, tr->dir);
8411	init_trace_flags_index(tr);
8412	__update_tracer_options(tr);
 
 
 
 
 
 
8413
8414	list_add(&tr->list, &ftrace_trace_arrays);
8415
8416	mutex_unlock(&trace_types_lock);
8417	mutex_unlock(&event_mutex);
8418
8419	return tr;
8420
8421 out_free_tr:
 
8422	free_trace_buffers(tr);
8423	free_cpumask_var(tr->tracing_cpumask);
8424	kfree(tr->name);
8425	kfree(tr);
8426
8427 out_unlock:
8428	mutex_unlock(&trace_types_lock);
8429	mutex_unlock(&event_mutex);
8430
8431	return ERR_PTR(ret);
8432}
8433EXPORT_SYMBOL_GPL(trace_array_create);
8434
8435static int instance_mkdir(const char *name)
8436{
8437	return PTR_ERR_OR_ZERO(trace_array_create(name));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8438}
8439
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8440static int __remove_instance(struct trace_array *tr)
8441{
8442	int i;
8443
8444	if (tr->ref || (tr->current_trace && tr->current_trace->ref))
 
8445		return -EBUSY;
8446
8447	list_del(&tr->list);
8448
8449	/* Disable all the flags that were enabled coming in */
8450	for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
8451		if ((1 << i) & ZEROED_TRACE_FLAGS)
8452			set_tracer_flag(tr, 1 << i, 0);
8453	}
8454
8455	tracing_set_nop(tr);
8456	clear_ftrace_function_probes(tr);
8457	event_trace_del_tracer(tr);
8458	ftrace_clear_pids(tr);
8459	ftrace_destroy_function_files(tr);
8460	tracefs_remove_recursive(tr->dir);
 
8461	free_trace_buffers(tr);
8462
8463	for (i = 0; i < tr->nr_topts; i++) {
8464		kfree(tr->topts[i].topts);
8465	}
8466	kfree(tr->topts);
8467
8468	free_cpumask_var(tr->tracing_cpumask);
8469	kfree(tr->name);
8470	kfree(tr);
8471	tr = NULL;
8472
8473	return 0;
8474}
8475
8476int trace_array_destroy(struct trace_array *tr)
8477{
 
8478	int ret;
8479
8480	if (!tr)
8481		return -EINVAL;
8482
8483	mutex_lock(&event_mutex);
8484	mutex_lock(&trace_types_lock);
8485
8486	ret = __remove_instance(tr);
 
 
 
 
 
 
 
 
8487
8488	mutex_unlock(&trace_types_lock);
8489	mutex_unlock(&event_mutex);
8490
8491	return ret;
8492}
8493EXPORT_SYMBOL_GPL(trace_array_destroy);
8494
8495static int instance_rmdir(const char *name)
8496{
8497	struct trace_array *tr;
8498	int ret;
8499
8500	mutex_lock(&event_mutex);
8501	mutex_lock(&trace_types_lock);
8502
8503	ret = -ENODEV;
8504	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
8505		if (tr->name && strcmp(tr->name, name) == 0) {
8506			ret = __remove_instance(tr);
8507			break;
8508		}
8509	}
8510
8511	mutex_unlock(&trace_types_lock);
8512	mutex_unlock(&event_mutex);
8513
8514	return ret;
8515}
8516
8517static __init void create_trace_instances(struct dentry *d_tracer)
8518{
 
 
8519	trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
8520							 instance_mkdir,
8521							 instance_rmdir);
8522	if (WARN_ON(!trace_instance_dir))
8523		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8524}
8525
8526static void
8527init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
8528{
8529	struct trace_event_file *file;
8530	int cpu;
8531
8532	trace_create_file("available_tracers", 0444, d_tracer,
8533			tr, &show_traces_fops);
8534
8535	trace_create_file("current_tracer", 0644, d_tracer,
8536			tr, &set_tracer_fops);
8537
8538	trace_create_file("tracing_cpumask", 0644, d_tracer,
8539			  tr, &tracing_cpumask_fops);
8540
8541	trace_create_file("trace_options", 0644, d_tracer,
8542			  tr, &tracing_iter_fops);
8543
8544	trace_create_file("trace", 0644, d_tracer,
8545			  tr, &tracing_fops);
8546
8547	trace_create_file("trace_pipe", 0444, d_tracer,
8548			  tr, &tracing_pipe_fops);
8549
8550	trace_create_file("buffer_size_kb", 0644, d_tracer,
8551			  tr, &tracing_entries_fops);
8552
8553	trace_create_file("buffer_total_size_kb", 0444, d_tracer,
8554			  tr, &tracing_total_entries_fops);
8555
8556	trace_create_file("free_buffer", 0200, d_tracer,
8557			  tr, &tracing_free_buffer_fops);
8558
8559	trace_create_file("trace_marker", 0220, d_tracer,
8560			  tr, &tracing_mark_fops);
8561
8562	file = __find_event_file(tr, "ftrace", "print");
8563	if (file && file->dir)
8564		trace_create_file("trigger", 0644, file->dir, file,
8565				  &event_trigger_fops);
8566	tr->trace_marker_file = file;
8567
8568	trace_create_file("trace_marker_raw", 0220, d_tracer,
8569			  tr, &tracing_mark_raw_fops);
8570
8571	trace_create_file("trace_clock", 0644, d_tracer, tr,
8572			  &trace_clock_fops);
8573
8574	trace_create_file("tracing_on", 0644, d_tracer,
8575			  tr, &rb_simple_fops);
8576
8577	trace_create_file("timestamp_mode", 0444, d_tracer, tr,
8578			  &trace_time_stamp_mode_fops);
8579
8580	tr->buffer_percent = 50;
8581
8582	trace_create_file("buffer_percent", 0444, d_tracer,
8583			tr, &buffer_percent_fops);
8584
8585	create_trace_options_dir(tr);
8586
8587#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
8588	trace_create_file("tracing_max_latency", 0644, d_tracer,
8589			&tr->max_latency, &tracing_max_lat_fops);
8590#endif
8591
8592	if (ftrace_create_function_files(tr, d_tracer))
8593		WARN(1, "Could not allocate function filter files");
8594
8595#ifdef CONFIG_TRACER_SNAPSHOT
8596	trace_create_file("snapshot", 0644, d_tracer,
8597			  tr, &snapshot_fops);
8598#endif
8599
8600	trace_create_file("error_log", 0644, d_tracer,
8601			  tr, &tracing_err_log_fops);
8602
8603	for_each_tracing_cpu(cpu)
8604		tracing_init_tracefs_percpu(tr, cpu);
8605
8606	ftrace_init_tracefs(tr, d_tracer);
8607}
8608
8609static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
8610{
8611	struct vfsmount *mnt;
8612	struct file_system_type *type;
8613
8614	/*
8615	 * To maintain backward compatibility for tools that mount
8616	 * debugfs to get to the tracing facility, tracefs is automatically
8617	 * mounted to the debugfs/tracing directory.
8618	 */
8619	type = get_fs_type("tracefs");
8620	if (!type)
8621		return NULL;
8622	mnt = vfs_submount(mntpt, type, "tracefs", NULL);
8623	put_filesystem(type);
8624	if (IS_ERR(mnt))
8625		return NULL;
8626	mntget(mnt);
8627
8628	return mnt;
8629}
8630
8631/**
8632 * tracing_init_dentry - initialize top level trace array
8633 *
8634 * This is called when creating files or directories in the tracing
8635 * directory. It is called via fs_initcall() by any of the boot up code
8636 * and expects to return the dentry of the top level tracing directory.
8637 */
8638struct dentry *tracing_init_dentry(void)
8639{
8640	struct trace_array *tr = &global_trace;
8641
 
 
 
 
 
8642	/* The top level trace array uses  NULL as parent */
8643	if (tr->dir)
8644		return NULL;
8645
8646	if (WARN_ON(!tracefs_initialized()) ||
8647		(IS_ENABLED(CONFIG_DEBUG_FS) &&
8648		 WARN_ON(!debugfs_initialized())))
8649		return ERR_PTR(-ENODEV);
8650
8651	/*
8652	 * As there may still be users that expect the tracing
8653	 * files to exist in debugfs/tracing, we must automount
8654	 * the tracefs file system there, so older tools still
8655	 * work with the newer kerenl.
8656	 */
8657	tr->dir = debugfs_create_automount("tracing", NULL,
8658					   trace_automount, NULL);
8659
8660	return NULL;
8661}
8662
8663extern struct trace_eval_map *__start_ftrace_eval_maps[];
8664extern struct trace_eval_map *__stop_ftrace_eval_maps[];
8665
8666static void __init trace_eval_init(void)
 
 
 
8667{
8668	int len;
8669
8670	len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
8671	trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
8672}
8673
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8674#ifdef CONFIG_MODULES
8675static void trace_module_add_evals(struct module *mod)
8676{
8677	if (!mod->num_trace_evals)
8678		return;
8679
8680	/*
8681	 * Modules with bad taint do not have events created, do
8682	 * not bother with enums either.
8683	 */
8684	if (trace_module_has_bad_taint(mod))
8685		return;
8686
8687	trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
8688}
8689
8690#ifdef CONFIG_TRACE_EVAL_MAP_FILE
8691static void trace_module_remove_evals(struct module *mod)
8692{
8693	union trace_eval_map_item *map;
8694	union trace_eval_map_item **last = &trace_eval_maps;
8695
8696	if (!mod->num_trace_evals)
8697		return;
8698
8699	mutex_lock(&trace_eval_mutex);
8700
8701	map = trace_eval_maps;
8702
8703	while (map) {
8704		if (map->head.mod == mod)
8705			break;
8706		map = trace_eval_jmp_to_tail(map);
8707		last = &map->tail.next;
8708		map = map->tail.next;
8709	}
8710	if (!map)
8711		goto out;
8712
8713	*last = trace_eval_jmp_to_tail(map)->tail.next;
8714	kfree(map);
8715 out:
8716	mutex_unlock(&trace_eval_mutex);
8717}
8718#else
8719static inline void trace_module_remove_evals(struct module *mod) { }
8720#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
8721
8722static int trace_module_notify(struct notifier_block *self,
8723			       unsigned long val, void *data)
8724{
8725	struct module *mod = data;
8726
8727	switch (val) {
8728	case MODULE_STATE_COMING:
8729		trace_module_add_evals(mod);
8730		break;
8731	case MODULE_STATE_GOING:
8732		trace_module_remove_evals(mod);
8733		break;
8734	}
8735
8736	return 0;
8737}
8738
8739static struct notifier_block trace_module_nb = {
8740	.notifier_call = trace_module_notify,
8741	.priority = 0,
8742};
8743#endif /* CONFIG_MODULES */
8744
8745static __init int tracer_init_tracefs(void)
8746{
8747	struct dentry *d_tracer;
8748
8749	trace_access_lock_init();
8750
8751	d_tracer = tracing_init_dentry();
8752	if (IS_ERR(d_tracer))
8753		return 0;
8754
8755	event_trace_init();
8756
8757	init_tracer_tracefs(&global_trace, d_tracer);
8758	ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
8759
8760	trace_create_file("tracing_thresh", 0644, d_tracer,
8761			&global_trace, &tracing_thresh_fops);
8762
8763	trace_create_file("README", 0444, d_tracer,
8764			NULL, &tracing_readme_fops);
8765
8766	trace_create_file("saved_cmdlines", 0444, d_tracer,
8767			NULL, &tracing_saved_cmdlines_fops);
8768
8769	trace_create_file("saved_cmdlines_size", 0644, d_tracer,
8770			  NULL, &tracing_saved_cmdlines_size_fops);
8771
8772	trace_create_file("saved_tgids", 0444, d_tracer,
8773			NULL, &tracing_saved_tgids_fops);
8774
8775	trace_eval_init();
8776
8777	trace_create_eval_file(d_tracer);
8778
8779#ifdef CONFIG_MODULES
8780	register_module_notifier(&trace_module_nb);
8781#endif
8782
8783#ifdef CONFIG_DYNAMIC_FTRACE
8784	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
8785			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
8786#endif
8787
8788	create_trace_instances(d_tracer);
8789
8790	update_tracer_options(&global_trace);
8791
8792	return 0;
8793}
8794
 
 
8795static int trace_panic_handler(struct notifier_block *this,
8796			       unsigned long event, void *unused)
8797{
8798	if (ftrace_dump_on_oops)
8799		ftrace_dump(ftrace_dump_on_oops);
8800	return NOTIFY_OK;
8801}
8802
8803static struct notifier_block trace_panic_notifier = {
8804	.notifier_call  = trace_panic_handler,
8805	.next           = NULL,
8806	.priority       = 150   /* priority: INT_MAX >= x >= 0 */
8807};
8808
8809static int trace_die_handler(struct notifier_block *self,
8810			     unsigned long val,
8811			     void *data)
8812{
8813	switch (val) {
8814	case DIE_OOPS:
8815		if (ftrace_dump_on_oops)
8816			ftrace_dump(ftrace_dump_on_oops);
8817		break;
8818	default:
8819		break;
8820	}
8821	return NOTIFY_OK;
8822}
8823
8824static struct notifier_block trace_die_notifier = {
8825	.notifier_call = trace_die_handler,
8826	.priority = 200
8827};
8828
8829/*
8830 * printk is set to max of 1024, we really don't need it that big.
8831 * Nothing should be printing 1000 characters anyway.
8832 */
8833#define TRACE_MAX_PRINT		1000
8834
8835/*
8836 * Define here KERN_TRACE so that we have one place to modify
8837 * it if we decide to change what log level the ftrace dump
8838 * should be at.
8839 */
8840#define KERN_TRACE		KERN_EMERG
8841
8842void
8843trace_printk_seq(struct trace_seq *s)
8844{
8845	/* Probably should print a warning here. */
8846	if (s->seq.len >= TRACE_MAX_PRINT)
8847		s->seq.len = TRACE_MAX_PRINT;
8848
8849	/*
8850	 * More paranoid code. Although the buffer size is set to
8851	 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
8852	 * an extra layer of protection.
8853	 */
8854	if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
8855		s->seq.len = s->seq.size - 1;
8856
8857	/* should be zero ended, but we are paranoid. */
8858	s->buffer[s->seq.len] = 0;
8859
8860	printk(KERN_TRACE "%s", s->buffer);
8861
8862	trace_seq_init(s);
8863}
8864
8865void trace_init_global_iter(struct trace_iterator *iter)
8866{
8867	iter->tr = &global_trace;
8868	iter->trace = iter->tr->current_trace;
8869	iter->cpu_file = RING_BUFFER_ALL_CPUS;
8870	iter->trace_buffer = &global_trace.trace_buffer;
8871
8872	if (iter->trace && iter->trace->open)
8873		iter->trace->open(iter);
8874
8875	/* Annotate start of buffers if we had overruns */
8876	if (ring_buffer_overruns(iter->trace_buffer->buffer))
8877		iter->iter_flags |= TRACE_FILE_ANNOTATE;
8878
8879	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
8880	if (trace_clocks[iter->tr->clock_id].in_ns)
8881		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
8882}
8883
8884void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
8885{
8886	/* use static because iter can be a bit big for the stack */
8887	static struct trace_iterator iter;
8888	static atomic_t dump_running;
8889	struct trace_array *tr = &global_trace;
8890	unsigned int old_userobj;
8891	unsigned long flags;
8892	int cnt = 0, cpu;
8893
8894	/* Only allow one dump user at a time. */
8895	if (atomic_inc_return(&dump_running) != 1) {
8896		atomic_dec(&dump_running);
8897		return;
8898	}
8899
8900	/*
8901	 * Always turn off tracing when we dump.
8902	 * We don't need to show trace output of what happens
8903	 * between multiple crashes.
8904	 *
8905	 * If the user does a sysrq-z, then they can re-enable
8906	 * tracing with echo 1 > tracing_on.
8907	 */
8908	tracing_off();
8909
8910	local_irq_save(flags);
8911	printk_nmi_direct_enter();
8912
8913	/* Simulate the iterator */
8914	trace_init_global_iter(&iter);
 
 
 
 
 
8915
8916	for_each_tracing_cpu(cpu) {
8917		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
8918	}
8919
8920	old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
8921
8922	/* don't look at user memory in panic mode */
8923	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
8924
8925	switch (oops_dump_mode) {
8926	case DUMP_ALL:
8927		iter.cpu_file = RING_BUFFER_ALL_CPUS;
8928		break;
8929	case DUMP_ORIG:
8930		iter.cpu_file = raw_smp_processor_id();
8931		break;
8932	case DUMP_NONE:
8933		goto out_enable;
8934	default:
8935		printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
8936		iter.cpu_file = RING_BUFFER_ALL_CPUS;
8937	}
8938
8939	printk(KERN_TRACE "Dumping ftrace buffer:\n");
8940
8941	/* Did function tracer already get disabled? */
8942	if (ftrace_is_dead()) {
8943		printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
8944		printk("#          MAY BE MISSING FUNCTION EVENTS\n");
8945	}
8946
8947	/*
8948	 * We need to stop all tracing on all CPUS to read the
8949	 * the next buffer. This is a bit expensive, but is
8950	 * not done often. We fill all what we can read,
8951	 * and then release the locks again.
8952	 */
8953
8954	while (!trace_empty(&iter)) {
8955
8956		if (!cnt)
8957			printk(KERN_TRACE "---------------------------------\n");
8958
8959		cnt++;
8960
8961		trace_iterator_reset(&iter);
8962		iter.iter_flags |= TRACE_FILE_LAT_FMT;
8963
8964		if (trace_find_next_entry_inc(&iter) != NULL) {
8965			int ret;
8966
8967			ret = print_trace_line(&iter);
8968			if (ret != TRACE_TYPE_NO_CONSUME)
8969				trace_consume(&iter);
8970		}
8971		touch_nmi_watchdog();
8972
8973		trace_printk_seq(&iter.seq);
8974	}
8975
8976	if (!cnt)
8977		printk(KERN_TRACE "   (ftrace buffer empty)\n");
8978	else
8979		printk(KERN_TRACE "---------------------------------\n");
8980
8981 out_enable:
8982	tr->trace_flags |= old_userobj;
8983
8984	for_each_tracing_cpu(cpu) {
8985		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
8986	}
8987	atomic_dec(&dump_running);
8988	printk_nmi_direct_exit();
8989	local_irq_restore(flags);
8990}
8991EXPORT_SYMBOL_GPL(ftrace_dump);
8992
8993int trace_run_command(const char *buf, int (*createfn)(int, char **))
8994{
8995	char **argv;
8996	int argc, ret;
8997
8998	argc = 0;
8999	ret = 0;
9000	argv = argv_split(GFP_KERNEL, buf, &argc);
9001	if (!argv)
9002		return -ENOMEM;
9003
9004	if (argc)
9005		ret = createfn(argc, argv);
9006
9007	argv_free(argv);
9008
9009	return ret;
9010}
9011
9012#define WRITE_BUFSIZE  4096
9013
9014ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
9015				size_t count, loff_t *ppos,
9016				int (*createfn)(int, char **))
9017{
9018	char *kbuf, *buf, *tmp;
9019	int ret = 0;
9020	size_t done = 0;
9021	size_t size;
9022
9023	kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
9024	if (!kbuf)
9025		return -ENOMEM;
9026
9027	while (done < count) {
9028		size = count - done;
9029
9030		if (size >= WRITE_BUFSIZE)
9031			size = WRITE_BUFSIZE - 1;
9032
9033		if (copy_from_user(kbuf, buffer + done, size)) {
9034			ret = -EFAULT;
9035			goto out;
9036		}
9037		kbuf[size] = '\0';
9038		buf = kbuf;
9039		do {
9040			tmp = strchr(buf, '\n');
9041			if (tmp) {
9042				*tmp = '\0';
9043				size = tmp - buf + 1;
9044			} else {
9045				size = strlen(buf);
9046				if (done + size < count) {
9047					if (buf != kbuf)
9048						break;
9049					/* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
9050					pr_warn("Line length is too long: Should be less than %d\n",
9051						WRITE_BUFSIZE - 2);
9052					ret = -EINVAL;
9053					goto out;
9054				}
9055			}
9056			done += size;
9057
9058			/* Remove comments */
9059			tmp = strchr(buf, '#');
9060
9061			if (tmp)
9062				*tmp = '\0';
9063
9064			ret = trace_run_command(buf, createfn);
9065			if (ret)
9066				goto out;
9067			buf += size;
9068
9069		} while (done < count);
9070	}
9071	ret = done;
9072
9073out:
9074	kfree(kbuf);
9075
9076	return ret;
9077}
9078
9079__init static int tracer_alloc_buffers(void)
9080{
9081	int ring_buf_size;
9082	int ret = -ENOMEM;
9083
 
 
 
 
 
 
9084	/*
9085	 * Make sure we don't accidently add more trace options
9086	 * than we have bits for.
9087	 */
9088	BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
9089
9090	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
9091		goto out;
9092
9093	if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
9094		goto out_free_buffer_mask;
9095
9096	/* Only allocate trace_printk buffers if a trace_printk exists */
9097	if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
9098		/* Must be called before global_trace.buffer is allocated */
9099		trace_printk_init_buffers();
9100
9101	/* To save memory, keep the ring buffer size to its minimum */
9102	if (ring_buffer_expanded)
9103		ring_buf_size = trace_buf_size;
9104	else
9105		ring_buf_size = 1;
9106
9107	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
9108	cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
9109
9110	raw_spin_lock_init(&global_trace.start_lock);
9111
9112	/*
9113	 * The prepare callbacks allocates some memory for the ring buffer. We
9114	 * don't free the buffer if the if the CPU goes down. If we were to free
9115	 * the buffer, then the user would lose any trace that was in the
9116	 * buffer. The memory will be removed once the "instance" is removed.
9117	 */
9118	ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
9119				      "trace/RB:preapre", trace_rb_cpu_prepare,
9120				      NULL);
9121	if (ret < 0)
9122		goto out_free_cpumask;
9123	/* Used for event triggers */
9124	ret = -ENOMEM;
9125	temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
9126	if (!temp_buffer)
9127		goto out_rm_hp_state;
9128
9129	if (trace_create_savedcmd() < 0)
9130		goto out_free_temp_buffer;
9131
9132	/* TODO: make the number of buffers hot pluggable with CPUS */
9133	if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
9134		printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
9135		WARN_ON(1);
9136		goto out_free_savedcmd;
9137	}
9138
9139	if (global_trace.buffer_disabled)
9140		tracing_off();
9141
9142	if (trace_boot_clock) {
9143		ret = tracing_set_clock(&global_trace, trace_boot_clock);
9144		if (ret < 0)
9145			pr_warn("Trace clock %s not defined, going back to default\n",
9146				trace_boot_clock);
9147	}
9148
9149	/*
9150	 * register_tracer() might reference current_trace, so it
9151	 * needs to be set before we register anything. This is
9152	 * just a bootstrap of current_trace anyway.
9153	 */
9154	global_trace.current_trace = &nop_trace;
9155
9156	global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9157
9158	ftrace_init_global_array_ops(&global_trace);
9159
9160	init_trace_flags_index(&global_trace);
9161
9162	register_tracer(&nop_trace);
9163
9164	/* Function tracing may start here (via kernel command line) */
9165	init_function_trace();
9166
9167	/* All seems OK, enable tracing */
9168	tracing_disabled = 0;
9169
9170	atomic_notifier_chain_register(&panic_notifier_list,
9171				       &trace_panic_notifier);
9172
9173	register_die_notifier(&trace_die_notifier);
9174
9175	global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
9176
9177	INIT_LIST_HEAD(&global_trace.systems);
9178	INIT_LIST_HEAD(&global_trace.events);
9179	INIT_LIST_HEAD(&global_trace.hist_vars);
9180	INIT_LIST_HEAD(&global_trace.err_log);
9181	list_add(&global_trace.list, &ftrace_trace_arrays);
9182
9183	apply_trace_boot_options();
9184
9185	register_snapshot_cmd();
9186
 
 
9187	return 0;
9188
9189out_free_savedcmd:
9190	free_saved_cmdlines_buffer(savedcmd);
9191out_free_temp_buffer:
9192	ring_buffer_free(temp_buffer);
9193out_rm_hp_state:
9194	cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
9195out_free_cpumask:
9196	free_cpumask_var(global_trace.tracing_cpumask);
9197out_free_buffer_mask:
9198	free_cpumask_var(tracing_buffer_mask);
9199out:
9200	return ret;
9201}
9202
9203void __init early_trace_init(void)
9204{
9205	if (tracepoint_printk) {
9206		tracepoint_print_iter =
9207			kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
9208		if (WARN_ON(!tracepoint_print_iter))
 
9209			tracepoint_printk = 0;
9210		else
9211			static_key_enable(&tracepoint_printk_key.key);
9212	}
9213	tracer_alloc_buffers();
9214}
9215
9216void __init trace_init(void)
9217{
9218	trace_event_init();
9219}
9220
9221__init static int clear_boot_tracer(void)
9222{
9223	/*
9224	 * The default tracer at boot buffer is an init section.
9225	 * This function is called in lateinit. If we did not
9226	 * find the boot tracer, then clear it out, to prevent
9227	 * later registration from accessing the buffer that is
9228	 * about to be freed.
9229	 */
9230	if (!default_bootup_tracer)
9231		return 0;
9232
9233	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
9234	       default_bootup_tracer);
9235	default_bootup_tracer = NULL;
9236
9237	return 0;
9238}
9239
9240fs_initcall(tracer_init_tracefs);
9241late_initcall_sync(clear_boot_tracer);
9242
9243#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
9244__init static int tracing_set_default_clock(void)
9245{
9246	/* sched_clock_stable() is determined in late_initcall */
9247	if (!trace_boot_clock && !sched_clock_stable()) {
 
 
 
 
 
9248		printk(KERN_WARNING
9249		       "Unstable clock detected, switching default tracing clock to \"global\"\n"
9250		       "If you want to keep using the local clock, then add:\n"
9251		       "  \"trace_clock=local\"\n"
9252		       "on the kernel command line\n");
9253		tracing_set_clock(&global_trace, "global");
9254	}
 
 
 
 
9255
 
 
 
 
 
 
 
 
 
9256	return 0;
9257}
9258late_initcall_sync(tracing_set_default_clock);
9259#endif