1/*
   2 * ring buffer based function tracer
   3 *
   4 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
   5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
   6 *
   7 * Originally taken from the RT patch by:
   8 *    Arnaldo Carvalho de Melo <acme@redhat.com>
   9 *
  10 * Based on code from the latency_tracer, that is:
  11 *  Copyright (C) 2004-2006 Ingo Molnar
  12 *  Copyright (C) 2004 Nadia Yvette Chambers
  13 */
  14#include <linux/ring_buffer.h>
  15#include <generated/utsrelease.h>
  16#include <linux/stacktrace.h>
  17#include <linux/writeback.h>
  18#include <linux/kallsyms.h>
  19#include <linux/seq_file.h>
  20#include <linux/notifier.h>
  21#include <linux/irqflags.h>
  22#include <linux/debugfs.h>
  23#include <linux/tracefs.h>
  24#include <linux/pagemap.h>
  25#include <linux/hardirq.h>
  26#include <linux/linkage.h>
  27#include <linux/uaccess.h>
  28#include <linux/kprobes.h>
  29#include <linux/ftrace.h>
  30#include <linux/module.h>
  31#include <linux/percpu.h>
  32#include <linux/splice.h>
  33#include <linux/kdebug.h>
  34#include <linux/string.h>
  35#include <linux/mount.h>
  36#include <linux/rwsem.h>
  37#include <linux/slab.h>
  38#include <linux/ctype.h>
  39#include <linux/init.h>
  40#include <linux/poll.h>
  41#include <linux/nmi.h>
  42#include <linux/fs.h>
  43#include <linux/sched/rt.h>
  44
  45#include "trace.h"
  46#include "trace_output.h"
  47
  48/*
  49 * On boot up, the ring buffer is set to the minimum size, so that
  50 * we do not waste memory on systems that are not using tracing.
  51 */
  52bool ring_buffer_expanded;
  53
  54/*
  55 * We need to change this state when a selftest is running.
  56 * A selftest will lurk into the ring-buffer to count the
  57 * entries inserted during the selftest although some concurrent
  58 * insertions into the ring-buffer such as trace_printk could occurred
  59 * at the same time, giving false positive or negative results.
  60 */
  61static bool __read_mostly tracing_selftest_running;
  62
  63/*
  64 * If a tracer is running, we do not want to run SELFTEST.
  65 */
  66bool __read_mostly tracing_selftest_disabled;
  67
  68/* Pipe tracepoints to printk */
  69struct trace_iterator *tracepoint_print_iter;
  70int tracepoint_printk;
  71
  72/* For tracers that don't implement custom flags */
  73static struct tracer_opt dummy_tracer_opt[] = {
  74	{ }
  75};
  76
  77static int
  78dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 
 
 
 
  79{
  80	return 0;
  81}
  82
  83/*
  84 * To prevent the comm cache from being overwritten when no
  85 * tracing is active, only save the comm when a trace event
  86 * occurred.
  87 */
  88static DEFINE_PER_CPU(bool, trace_cmdline_save);
  89
  90/*
  91 * Kill all tracing for good (never come back).
  92 * It is initialized to 1 but will turn to zero if the initialization
  93 * of the tracer is successful. But that is the only place that sets
  94 * this back to zero.
  95 */
  96static int tracing_disabled = 1;
  97
 
 
  98cpumask_var_t __read_mostly	tracing_buffer_mask;
  99
 100/*
 101 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
 102 *
 103 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
 104 * is set, then ftrace_dump is called. This will output the contents
 105 * of the ftrace buffers to the console.  This is very useful for
 106 * capturing traces that lead to crashes and outputing it to a
 107 * serial console.
 108 *
 109 * It is default off, but you can enable it with either specifying
 110 * "ftrace_dump_on_oops" in the kernel command line, or setting
 111 * /proc/sys/kernel/ftrace_dump_on_oops
 112 * Set 1 if you want to dump buffers of all CPUs
 113 * Set 2 if you want to dump the buffer of the CPU that triggered oops
 114 */
 115
 116enum ftrace_dump_mode ftrace_dump_on_oops;
 117
 118/* When set, tracing will stop when a WARN*() is hit */
 119int __disable_trace_on_warning;
 120
 121#ifdef CONFIG_TRACE_ENUM_MAP_FILE
 122/* Map of enums to their values, for "enum_map" file */
 123struct trace_enum_map_head {
 124	struct module			*mod;
 125	unsigned long			length;
 126};
 127
 128union trace_enum_map_item;
 129
 130struct trace_enum_map_tail {
 131	/*
 132	 * "end" is first and points to NULL as it must be different
 133	 * than "mod" or "enum_string"
 134	 */
 135	union trace_enum_map_item	*next;
 136	const char			*end;	/* points to NULL */
 137};
 138
 139static DEFINE_MUTEX(trace_enum_mutex);
 140
 141/*
 142 * The trace_enum_maps are saved in an array with two extra elements,
 143 * one at the beginning, and one at the end. The beginning item contains
 144 * the count of the saved maps (head.length), and the module they
 145 * belong to if not built in (head.mod). The ending item contains a
 146 * pointer to the next array of saved enum_map items.
 147 */
 148union trace_enum_map_item {
 149	struct trace_enum_map		map;
 150	struct trace_enum_map_head	head;
 151	struct trace_enum_map_tail	tail;
 152};
 153
 154static union trace_enum_map_item *trace_enum_maps;
 155#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
 156
 157static int tracing_set_tracer(struct trace_array *tr, const char *buf);
 158
 159#define MAX_TRACER_SIZE		100
 160static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
 161static char *default_bootup_tracer;
 162
 163static bool allocate_snapshot;
 164
 165static int __init set_cmdline_ftrace(char *str)
 166{
 167	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 168	default_bootup_tracer = bootup_tracer_buf;
 169	/* We are using ftrace early, expand it */
 170	ring_buffer_expanded = true;
 171	return 1;
 172}
 173__setup("ftrace=", set_cmdline_ftrace);
 174
 175static int __init set_ftrace_dump_on_oops(char *str)
 176{
 177	if (*str++ != '=' || !*str) {
 178		ftrace_dump_on_oops = DUMP_ALL;
 179		return 1;
 180	}
 181
 182	if (!strcmp("orig_cpu", str)) {
 183		ftrace_dump_on_oops = DUMP_ORIG;
 184                return 1;
 185        }
 186
 187        return 0;
 188}
 189__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
 190
 191static int __init stop_trace_on_warning(char *str)
 192{
 193	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
 194		__disable_trace_on_warning = 1;
 195	return 1;
 196}
 197__setup("traceoff_on_warning", stop_trace_on_warning);
 198
 199static int __init boot_alloc_snapshot(char *str)
 200{
 201	allocate_snapshot = true;
 202	/* We also need the main ring buffer expanded */
 203	ring_buffer_expanded = true;
 204	return 1;
 205}
 206__setup("alloc_snapshot", boot_alloc_snapshot);
 207
 208
 209static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
 210
 211static int __init set_trace_boot_options(char *str)
 212{
 213	strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
 214	return 0;
 215}
 216__setup("trace_options=", set_trace_boot_options);
 217
 218static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
 219static char *trace_boot_clock __initdata;
 220
 221static int __init set_trace_boot_clock(char *str)
 222{
 223	strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
 224	trace_boot_clock = trace_boot_clock_buf;
 225	return 0;
 226}
 227__setup("trace_clock=", set_trace_boot_clock);
 228
 229static int __init set_tracepoint_printk(char *str)
 230{
 231	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
 232		tracepoint_printk = 1;
 233	return 1;
 234}
 235__setup("tp_printk", set_tracepoint_printk);
 236
 237unsigned long long ns2usecs(cycle_t nsec)
 238{
 239	nsec += 500;
 240	do_div(nsec, 1000);
 241	return nsec;
 242}
 243
 244/* trace_flags holds trace_options default values */
 245#define TRACE_DEFAULT_FLAGS						\
 246	(FUNCTION_DEFAULT_FLAGS |					\
 247	 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |			\
 248	 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO |		\
 249	 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |			\
 250	 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
 251
 252/* trace_options that are only supported by global_trace */
 253#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK |			\
 254	       TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
 255
 256
 257/*
 258 * The global_trace is the descriptor that holds the tracing
 259 * buffers for the live tracing. For each CPU, it contains
 260 * a link list of pages that will store trace entries. The
 261 * page descriptor of the pages in the memory is used to hold
 262 * the link list by linking the lru item in the page descriptor
 263 * to each of the pages in the buffer per CPU.
 264 *
 265 * For each active CPU there is a data field that holds the
 266 * pages for the buffer for that CPU. Each CPU has the same number
 267 * of pages allocated for its buffer.
 268 */
 269static struct trace_array global_trace = {
 270	.trace_flags = TRACE_DEFAULT_FLAGS,
 271};
 272
 273LIST_HEAD(ftrace_trace_arrays);
 274
 275int trace_array_get(struct trace_array *this_tr)
 
 
 276{
 277	struct trace_array *tr;
 278	int ret = -ENODEV;
 279
 280	mutex_lock(&trace_types_lock);
 281	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
 282		if (tr == this_tr) {
 283			tr->ref++;
 284			ret = 0;
 285			break;
 286		}
 287	}
 288	mutex_unlock(&trace_types_lock);
 289
 290	return ret;
 291}
 
 292
 293static void __trace_array_put(struct trace_array *this_tr)
 294{
 295	WARN_ON(!this_tr->ref);
 296	this_tr->ref--;
 297}
 298
 299void trace_array_put(struct trace_array *this_tr)
 300{
 301	mutex_lock(&trace_types_lock);
 302	__trace_array_put(this_tr);
 303	mutex_unlock(&trace_types_lock);
 304}
 305
 306int filter_check_discard(struct trace_event_file *file, void *rec,
 307			 struct ring_buffer *buffer,
 308			 struct ring_buffer_event *event)
 309{
 310	if (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
 311	    !filter_match_preds(file->filter, rec)) {
 312		ring_buffer_discard_commit(buffer, event);
 313		return 1;
 314	}
 315
 316	return 0;
 317}
 318EXPORT_SYMBOL_GPL(filter_check_discard);
 319
 320int call_filter_check_discard(struct trace_event_call *call, void *rec,
 321			      struct ring_buffer *buffer,
 322			      struct ring_buffer_event *event)
 323{
 324	if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
 325	    !filter_match_preds(call->filter, rec)) {
 326		ring_buffer_discard_commit(buffer, event);
 327		return 1;
 328	}
 329
 330	return 0;
 331}
 332EXPORT_SYMBOL_GPL(call_filter_check_discard);
 333
 334static cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
 335{
 336	u64 ts;
 337
 338	/* Early boot up does not have a buffer yet */
 339	if (!buf->buffer)
 340		return trace_clock_local();
 341
 342	ts = ring_buffer_time_stamp(buf->buffer, cpu);
 343	ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
 344
 345	return ts;
 346}
 347
 348cycle_t ftrace_now(int cpu)
 349{
 350	return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
 351}
 
 
 
 
 
 
 
 
 
 
 
 
 352
 353/**
 354 * tracing_is_enabled - Show if global_trace has been disabled
 355 *
 356 * Shows if the global trace has been enabled or not. It uses the
 357 * mirror flag "buffer_disabled" to be used in fast paths such as for
 358 * the irqsoff tracer. But it may be inaccurate due to races. If you
 359 * need to know the accurate state, use tracing_is_on() which is a little
 360 * slower, but accurate.
 361 */
 362int tracing_is_enabled(void)
 363{
 364	/*
 365	 * For quick access (irqsoff uses this in fast path), just
 366	 * return the mirror variable of the state of the ring buffer.
 367	 * It's a little racy, but we don't really care.
 368	 */
 369	smp_rmb();
 370	return !global_trace.buffer_disabled;
 371}
 372
 373/*
 374 * trace_buf_size is the size in bytes that is allocated
 375 * for a buffer. Note, the number of bytes is always rounded
 376 * to page size.
 377 *
 378 * This number is purposely set to a low number of 16384.
 379 * If the dump on oops happens, it will be much appreciated
 380 * to not have to wait for all that output. Anyway this can be
 381 * boot time and run time configurable.
 382 */
 383#define TRACE_BUF_SIZE_DEFAULT	1441792UL /* 16384 * 88 (sizeof(entry)) */
 384
 385static unsigned long		trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
 386
 387/* trace_types holds a link list of available tracers. */
 388static struct tracer		*trace_types __read_mostly;
 389
 
 
 
 390/*
 391 * trace_types_lock is used to protect the trace_types list.
 392 */
 393DEFINE_MUTEX(trace_types_lock);
 394
 395/*
 396 * serialize the access of the ring buffer
 397 *
 398 * ring buffer serializes readers, but it is low level protection.
 399 * The validity of the events (which returns by ring_buffer_peek() ..etc)
 400 * are not protected by ring buffer.
 401 *
 402 * The content of events may become garbage if we allow other process consumes
 403 * these events concurrently:
 404 *   A) the page of the consumed events may become a normal page
 405 *      (not reader page) in ring buffer, and this page will be rewrited
 406 *      by events producer.
 407 *   B) The page of the consumed events may become a page for splice_read,
 408 *      and this page will be returned to system.
 409 *
 410 * These primitives allow multi process access to different cpu ring buffer
 411 * concurrently.
 412 *
 413 * These primitives don't distinguish read-only and read-consume access.
 414 * Multi read-only access are also serialized.
 415 */
 416
 417#ifdef CONFIG_SMP
 418static DECLARE_RWSEM(all_cpu_access_lock);
 419static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
 420
 421static inline void trace_access_lock(int cpu)
 422{
 423	if (cpu == RING_BUFFER_ALL_CPUS) {
 424		/* gain it for accessing the whole ring buffer. */
 425		down_write(&all_cpu_access_lock);
 426	} else {
 427		/* gain it for accessing a cpu ring buffer. */
 428
 429		/* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
 430		down_read(&all_cpu_access_lock);
 431
 432		/* Secondly block other access to this @cpu ring buffer. */
 433		mutex_lock(&per_cpu(cpu_access_lock, cpu));
 434	}
 435}
 436
 437static inline void trace_access_unlock(int cpu)
 438{
 439	if (cpu == RING_BUFFER_ALL_CPUS) {
 440		up_write(&all_cpu_access_lock);
 441	} else {
 442		mutex_unlock(&per_cpu(cpu_access_lock, cpu));
 443		up_read(&all_cpu_access_lock);
 444	}
 445}
 446
 447static inline void trace_access_lock_init(void)
 448{
 449	int cpu;
 450
 451	for_each_possible_cpu(cpu)
 452		mutex_init(&per_cpu(cpu_access_lock, cpu));
 453}
 454
 455#else
 456
 457static DEFINE_MUTEX(access_lock);
 458
 459static inline void trace_access_lock(int cpu)
 460{
 461	(void)cpu;
 462	mutex_lock(&access_lock);
 463}
 464
 465static inline void trace_access_unlock(int cpu)
 466{
 467	(void)cpu;
 468	mutex_unlock(&access_lock);
 469}
 470
 471static inline void trace_access_lock_init(void)
 472{
 473}
 474
 475#endif
 476
 477#ifdef CONFIG_STACKTRACE
 478static void __ftrace_trace_stack(struct ring_buffer *buffer,
 479				 unsigned long flags,
 480				 int skip, int pc, struct pt_regs *regs);
 481static inline void ftrace_trace_stack(struct trace_array *tr,
 482				      struct ring_buffer *buffer,
 483				      unsigned long flags,
 484				      int skip, int pc, struct pt_regs *regs);
 485
 486#else
 487static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
 488					unsigned long flags,
 489					int skip, int pc, struct pt_regs *regs)
 490{
 491}
 492static inline void ftrace_trace_stack(struct trace_array *tr,
 493				      struct ring_buffer *buffer,
 494				      unsigned long flags,
 495				      int skip, int pc, struct pt_regs *regs)
 496{
 497}
 498
 499#endif
 
 500
 501static void tracer_tracing_on(struct trace_array *tr)
 502{
 503	if (tr->trace_buffer.buffer)
 504		ring_buffer_record_on(tr->trace_buffer.buffer);
 505	/*
 506	 * This flag is looked at when buffers haven't been allocated
 507	 * yet, or by some tracers (like irqsoff), that just want to
 508	 * know if the ring buffer has been disabled, but it can handle
 509	 * races of where it gets disabled but we still do a record.
 510	 * As the check is in the fast path of the tracers, it is more
 511	 * important to be fast than accurate.
 512	 */
 513	tr->buffer_disabled = 0;
 514	/* Make the flag seen by readers */
 515	smp_wmb();
 516}
 517
 
 
 518/**
 519 * tracing_on - enable tracing buffers
 520 *
 521 * This function enables tracing buffers that may have been
 522 * disabled with tracing_off.
 523 */
 524void tracing_on(void)
 525{
 526	tracer_tracing_on(&global_trace);
 527}
 528EXPORT_SYMBOL_GPL(tracing_on);
 529
 530/**
 531 * __trace_puts - write a constant string into the trace buffer.
 532 * @ip:	   The address of the caller
 533 * @str:   The constant string to write
 534 * @size:  The size of the string.
 535 */
 536int __trace_puts(unsigned long ip, const char *str, int size)
 537{
 538	struct ring_buffer_event *event;
 539	struct ring_buffer *buffer;
 540	struct print_entry *entry;
 541	unsigned long irq_flags;
 542	int alloc;
 543	int pc;
 544
 545	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
 546		return 0;
 547
 548	pc = preempt_count();
 549
 550	if (unlikely(tracing_selftest_running || tracing_disabled))
 551		return 0;
 552
 553	alloc = sizeof(*entry) + size + 2; /* possible \n added */
 554
 555	local_save_flags(irq_flags);
 556	buffer = global_trace.trace_buffer.buffer;
 557	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, 
 558					  irq_flags, pc);
 559	if (!event)
 560		return 0;
 561
 562	entry = ring_buffer_event_data(event);
 563	entry->ip = ip;
 564
 565	memcpy(&entry->buf, str, size);
 566
 567	/* Add a newline if necessary */
 568	if (entry->buf[size - 1] != '\n') {
 569		entry->buf[size] = '\n';
 570		entry->buf[size + 1] = '\0';
 571	} else
 572		entry->buf[size] = '\0';
 573
 574	__buffer_unlock_commit(buffer, event);
 575	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
 576
 577	return size;
 578}
 579EXPORT_SYMBOL_GPL(__trace_puts);
 580
 581/**
 582 * __trace_bputs - write the pointer to a constant string into trace buffer
 583 * @ip:	   The address of the caller
 584 * @str:   The constant string to write to the buffer to
 585 */
 586int __trace_bputs(unsigned long ip, const char *str)
 587{
 588	struct ring_buffer_event *event;
 589	struct ring_buffer *buffer;
 590	struct bputs_entry *entry;
 591	unsigned long irq_flags;
 592	int size = sizeof(struct bputs_entry);
 593	int pc;
 594
 595	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
 596		return 0;
 597
 598	pc = preempt_count();
 599
 600	if (unlikely(tracing_selftest_running || tracing_disabled))
 601		return 0;
 602
 603	local_save_flags(irq_flags);
 604	buffer = global_trace.trace_buffer.buffer;
 605	event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
 606					  irq_flags, pc);
 607	if (!event)
 608		return 0;
 609
 610	entry = ring_buffer_event_data(event);
 611	entry->ip			= ip;
 612	entry->str			= str;
 613
 614	__buffer_unlock_commit(buffer, event);
 615	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
 616
 617	return 1;
 618}
 619EXPORT_SYMBOL_GPL(__trace_bputs);
 620
 621#ifdef CONFIG_TRACER_SNAPSHOT
 622/**
 623 * trace_snapshot - take a snapshot of the current buffer.
 624 *
 625 * This causes a swap between the snapshot buffer and the current live
 626 * tracing buffer. You can use this to take snapshots of the live
 627 * trace when some condition is triggered, but continue to trace.
 628 *
 629 * Note, make sure to allocate the snapshot with either
 630 * a tracing_snapshot_alloc(), or by doing it manually
 631 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
 632 *
 633 * If the snapshot buffer is not allocated, it will stop tracing.
 634 * Basically making a permanent snapshot.
 635 */
 636void tracing_snapshot(void)
 637{
 638	struct trace_array *tr = &global_trace;
 639	struct tracer *tracer = tr->current_trace;
 640	unsigned long flags;
 641
 642	if (in_nmi()) {
 643		internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
 644		internal_trace_puts("*** snapshot is being ignored        ***\n");
 645		return;
 646	}
 647
 648	if (!tr->allocated_snapshot) {
 649		internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
 650		internal_trace_puts("*** stopping trace here!   ***\n");
 651		tracing_off();
 652		return;
 653	}
 654
 655	/* Note, snapshot can not be used when the tracer uses it */
 656	if (tracer->use_max_tr) {
 657		internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
 658		internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
 659		return;
 660	}
 661
 662	local_irq_save(flags);
 663	update_max_tr(tr, current, smp_processor_id());
 664	local_irq_restore(flags);
 665}
 666EXPORT_SYMBOL_GPL(tracing_snapshot);
 667
 668static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
 669					struct trace_buffer *size_buf, int cpu_id);
 670static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
 671
 672static int alloc_snapshot(struct trace_array *tr)
 673{
 674	int ret;
 675
 676	if (!tr->allocated_snapshot) {
 677
 678		/* allocate spare buffer */
 679		ret = resize_buffer_duplicate_size(&tr->max_buffer,
 680				   &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
 681		if (ret < 0)
 682			return ret;
 683
 684		tr->allocated_snapshot = true;
 685	}
 686
 687	return 0;
 688}
 689
 690static void free_snapshot(struct trace_array *tr)
 691{
 692	/*
 693	 * We don't free the ring buffer. instead, resize it because
 694	 * The max_tr ring buffer has some state (e.g. ring->clock) and
 695	 * we want preserve it.
 696	 */
 697	ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
 698	set_buffer_entries(&tr->max_buffer, 1);
 699	tracing_reset_online_cpus(&tr->max_buffer);
 700	tr->allocated_snapshot = false;
 701}
 702
 703/**
 704 * tracing_alloc_snapshot - allocate snapshot buffer.
 705 *
 706 * This only allocates the snapshot buffer if it isn't already
 707 * allocated - it doesn't also take a snapshot.
 708 *
 709 * This is meant to be used in cases where the snapshot buffer needs
 710 * to be set up for events that can't sleep but need to be able to
 711 * trigger a snapshot.
 712 */
 713int tracing_alloc_snapshot(void)
 714{
 715	struct trace_array *tr = &global_trace;
 716	int ret;
 717
 718	ret = alloc_snapshot(tr);
 719	WARN_ON(ret < 0);
 720
 721	return ret;
 722}
 723EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
 724
 725/**
 726 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
 727 *
 728 * This is similar to trace_snapshot(), but it will allocate the
 729 * snapshot buffer if it isn't already allocated. Use this only
 730 * where it is safe to sleep, as the allocation may sleep.
 731 *
 732 * This causes a swap between the snapshot buffer and the current live
 733 * tracing buffer. You can use this to take snapshots of the live
 734 * trace when some condition is triggered, but continue to trace.
 735 */
 736void tracing_snapshot_alloc(void)
 737{
 738	int ret;
 739
 740	ret = tracing_alloc_snapshot();
 741	if (ret < 0)
 742		return;
 743
 744	tracing_snapshot();
 745}
 746EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
 747#else
 748void tracing_snapshot(void)
 749{
 750	WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
 751}
 752EXPORT_SYMBOL_GPL(tracing_snapshot);
 753int tracing_alloc_snapshot(void)
 754{
 755	WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
 756	return -ENODEV;
 757}
 758EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
 759void tracing_snapshot_alloc(void)
 760{
 761	/* Give warning */
 762	tracing_snapshot();
 763}
 764EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
 765#endif /* CONFIG_TRACER_SNAPSHOT */
 766
 767static void tracer_tracing_off(struct trace_array *tr)
 768{
 769	if (tr->trace_buffer.buffer)
 770		ring_buffer_record_off(tr->trace_buffer.buffer);
 771	/*
 772	 * This flag is looked at when buffers haven't been allocated
 773	 * yet, or by some tracers (like irqsoff), that just want to
 774	 * know if the ring buffer has been disabled, but it can handle
 775	 * races of where it gets disabled but we still do a record.
 776	 * As the check is in the fast path of the tracers, it is more
 777	 * important to be fast than accurate.
 778	 */
 779	tr->buffer_disabled = 1;
 780	/* Make the flag seen by readers */
 781	smp_wmb();
 782}
 
 783
 784/**
 785 * tracing_off - turn off tracing buffers
 786 *
 787 * This function stops the tracing buffers from recording data.
 788 * It does not disable any overhead the tracers themselves may
 789 * be causing. This function simply causes all recording to
 790 * the ring buffers to fail.
 791 */
 792void tracing_off(void)
 793{
 794	tracer_tracing_off(&global_trace);
 
 
 
 
 
 
 
 
 795}
 796EXPORT_SYMBOL_GPL(tracing_off);
 797
 798void disable_trace_on_warning(void)
 799{
 800	if (__disable_trace_on_warning)
 801		tracing_off();
 802}
 803
 804/**
 805 * tracer_tracing_is_on - show real state of ring buffer enabled
 806 * @tr : the trace array to know if ring buffer is enabled
 807 *
 808 * Shows real state of the ring buffer if it is enabled or not.
 809 */
 810static int tracer_tracing_is_on(struct trace_array *tr)
 811{
 812	if (tr->trace_buffer.buffer)
 813		return ring_buffer_record_is_on(tr->trace_buffer.buffer);
 814	return !tr->buffer_disabled;
 815}
 
 816
 817/**
 818 * tracing_is_on - show state of ring buffers enabled
 
 
 
 
 819 */
 820int tracing_is_on(void)
 821{
 822	return tracer_tracing_is_on(&global_trace);
 
 
 
 
 823}
 824EXPORT_SYMBOL_GPL(tracing_is_on);
 825
 826static int __init set_buf_size(char *str)
 827{
 828	unsigned long buf_size;
 829
 830	if (!str)
 831		return 0;
 832	buf_size = memparse(str, &str);
 833	/* nr_entries can not be zero */
 834	if (buf_size == 0)
 835		return 0;
 836	trace_buf_size = buf_size;
 837	return 1;
 838}
 839__setup("trace_buf_size=", set_buf_size);
 840
 841static int __init set_tracing_thresh(char *str)
 842{
 843	unsigned long threshold;
 844	int ret;
 845
 846	if (!str)
 847		return 0;
 848	ret = kstrtoul(str, 0, &threshold);
 849	if (ret < 0)
 850		return 0;
 851	tracing_thresh = threshold * 1000;
 852	return 1;
 853}
 854__setup("tracing_thresh=", set_tracing_thresh);
 855
 856unsigned long nsecs_to_usecs(unsigned long nsecs)
 857{
 858	return nsecs / 1000;
 859}
 860
 861/*
 862 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
 863 * It uses C(a, b) where 'a' is the enum name and 'b' is the string that
 864 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
 865 * of strings in the order that the enums were defined.
 866 */
 867#undef C
 868#define C(a, b) b
 869
 870/* These must match the bit postions in trace_iterator_flags */
 871static const char *trace_options[] = {
 872	TRACE_FLAGS
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 873	NULL
 874};
 875
 876static struct {
 877	u64 (*func)(void);
 878	const char *name;
 879	int in_ns;		/* is this clock in nanoseconds? */
 880} trace_clocks[] = {
 881	{ trace_clock_local,		"local",	1 },
 882	{ trace_clock_global,		"global",	1 },
 883	{ trace_clock_counter,		"counter",	0 },
 884	{ trace_clock_jiffies,		"uptime",	0 },
 885	{ trace_clock,			"perf",		1 },
 886	{ ktime_get_mono_fast_ns,	"mono",		1 },
 887	{ ktime_get_raw_fast_ns,	"mono_raw",	1 },
 888	ARCH_TRACE_CLOCKS
 889};
 890
 
 
 891/*
 892 * trace_parser_get_init - gets the buffer for trace parser
 893 */
 894int trace_parser_get_init(struct trace_parser *parser, int size)
 895{
 896	memset(parser, 0, sizeof(*parser));
 897
 898	parser->buffer = kmalloc(size, GFP_KERNEL);
 899	if (!parser->buffer)
 900		return 1;
 901
 902	parser->size = size;
 903	return 0;
 904}
 905
 906/*
 907 * trace_parser_put - frees the buffer for trace parser
 908 */
 909void trace_parser_put(struct trace_parser *parser)
 910{
 911	kfree(parser->buffer);
 912}
 913
 914/*
 915 * trace_get_user - reads the user input string separated by  space
 916 * (matched by isspace(ch))
 917 *
 918 * For each string found the 'struct trace_parser' is updated,
 919 * and the function returns.
 920 *
 921 * Returns number of bytes read.
 922 *
 923 * See kernel/trace/trace.h for 'struct trace_parser' details.
 924 */
 925int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 926	size_t cnt, loff_t *ppos)
 927{
 928	char ch;
 929	size_t read = 0;
 930	ssize_t ret;
 931
 932	if (!*ppos)
 933		trace_parser_clear(parser);
 934
 935	ret = get_user(ch, ubuf++);
 936	if (ret)
 937		goto out;
 938
 939	read++;
 940	cnt--;
 941
 942	/*
 943	 * The parser is not finished with the last write,
 944	 * continue reading the user input without skipping spaces.
 945	 */
 946	if (!parser->cont) {
 947		/* skip white space */
 948		while (cnt && isspace(ch)) {
 949			ret = get_user(ch, ubuf++);
 950			if (ret)
 951				goto out;
 952			read++;
 953			cnt--;
 954		}
 955
 956		/* only spaces were written */
 957		if (isspace(ch)) {
 958			*ppos += read;
 959			ret = read;
 960			goto out;
 961		}
 962
 963		parser->idx = 0;
 964	}
 965
 966	/* read the non-space input */
 967	while (cnt && !isspace(ch)) {
 968		if (parser->idx < parser->size - 1)
 969			parser->buffer[parser->idx++] = ch;
 970		else {
 971			ret = -EINVAL;
 972			goto out;
 973		}
 974		ret = get_user(ch, ubuf++);
 975		if (ret)
 976			goto out;
 977		read++;
 978		cnt--;
 979	}
 980
 981	/* We either got finished input or we have to wait for another call. */
 982	if (isspace(ch)) {
 983		parser->buffer[parser->idx] = 0;
 984		parser->cont = false;
 985	} else if (parser->idx < parser->size - 1) {
 986		parser->cont = true;
 987		parser->buffer[parser->idx++] = ch;
 988	} else {
 989		ret = -EINVAL;
 990		goto out;
 991	}
 992
 993	*ppos += read;
 994	ret = read;
 995
 996out:
 997	return ret;
 998}
 999
1000/* TODO add a seq_buf_to_buffer() */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1001static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1002{
1003	int len;
1004
1005	if (trace_seq_used(s) <= s->seq.readpos)
1006		return -EBUSY;
1007
1008	len = trace_seq_used(s) - s->seq.readpos;
1009	if (cnt > len)
1010		cnt = len;
1011	memcpy(buf, s->buffer + s->seq.readpos, cnt);
1012
1013	s->seq.readpos += cnt;
1014	return cnt;
1015}
1016
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1017unsigned long __read_mostly	tracing_thresh;
1018
1019#ifdef CONFIG_TRACER_MAX_TRACE
 
 
1020/*
1021 * Copy the new maximum trace into the separate maximum-trace
1022 * structure. (this way the maximum trace is permanently saved,
1023 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
1024 */
1025static void
1026__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1027{
1028	struct trace_buffer *trace_buf = &tr->trace_buffer;
1029	struct trace_buffer *max_buf = &tr->max_buffer;
1030	struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1031	struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1032
1033	max_buf->cpu = cpu;
1034	max_buf->time_start = data->preempt_timestamp;
1035
1036	max_data->saved_latency = tr->max_latency;
 
1037	max_data->critical_start = data->critical_start;
1038	max_data->critical_end = data->critical_end;
1039
1040	memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1041	max_data->pid = tsk->pid;
1042	/*
1043	 * If tsk == current, then use current_uid(), as that does not use
1044	 * RCU. The irq tracer can be called out of RCU scope.
1045	 */
1046	if (tsk == current)
1047		max_data->uid = current_uid();
1048	else
1049		max_data->uid = task_uid(tsk);
1050
1051	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1052	max_data->policy = tsk->policy;
1053	max_data->rt_priority = tsk->rt_priority;
1054
1055	/* record this tasks comm */
1056	tracing_record_cmdline(tsk);
1057}
1058
1059/**
1060 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1061 * @tr: tracer
1062 * @tsk: the task with the latency
1063 * @cpu: The cpu that initiated the trace.
1064 *
1065 * Flip the buffers between the @tr and the max_tr and record information
1066 * about which task was the cause of this latency.
1067 */
1068void
1069update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1070{
1071	struct ring_buffer *buf;
1072
1073	if (tr->stop_count)
1074		return;
1075
1076	WARN_ON_ONCE(!irqs_disabled());
1077
1078	if (!tr->allocated_snapshot) {
1079		/* Only the nop tracer should hit this when disabling */
1080		WARN_ON_ONCE(tr->current_trace != &nop_trace);
1081		return;
1082	}
 
1083
1084	arch_spin_lock(&tr->max_lock);
1085
1086	buf = tr->trace_buffer.buffer;
1087	tr->trace_buffer.buffer = tr->max_buffer.buffer;
1088	tr->max_buffer.buffer = buf;
1089
1090	__update_max_tr(tr, tsk, cpu);
1091	arch_spin_unlock(&tr->max_lock);
1092}
1093
1094/**
1095 * update_max_tr_single - only copy one trace over, and reset the rest
1096 * @tr - tracer
1097 * @tsk - task with the latency
1098 * @cpu - the cpu of the buffer to copy.
1099 *
1100 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1101 */
1102void
1103update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1104{
1105	int ret;
1106
1107	if (tr->stop_count)
1108		return;
1109
1110	WARN_ON_ONCE(!irqs_disabled());
1111	if (!tr->allocated_snapshot) {
1112		/* Only the nop tracer should hit this when disabling */
1113		WARN_ON_ONCE(tr->current_trace != &nop_trace);
1114		return;
1115	}
1116
1117	arch_spin_lock(&tr->max_lock);
1118
1119	ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1120
1121	if (ret == -EBUSY) {
1122		/*
1123		 * We failed to swap the buffer due to a commit taking
1124		 * place on this CPU. We fail to record, but we reset
1125		 * the max trace buffer (no one writes directly to it)
1126		 * and flag that it failed.
1127		 */
1128		trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1129			"Failed to swap buffers due to commit in progress\n");
1130	}
1131
1132	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1133
1134	__update_max_tr(tr, tsk, cpu);
1135	arch_spin_unlock(&tr->max_lock);
1136}
1137#endif /* CONFIG_TRACER_MAX_TRACE */
1138
1139static int wait_on_pipe(struct trace_iterator *iter, bool full)
1140{
1141	/* Iterators are static, they should be filled or empty */
1142	if (trace_buffer_iter(iter, iter->cpu_file))
1143		return 0;
1144
1145	return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
1146				full);
1147}
1148
1149#ifdef CONFIG_FTRACE_STARTUP_TEST
1150static int run_tracer_selftest(struct tracer *type)
1151{
1152	struct trace_array *tr = &global_trace;
1153	struct tracer *saved_tracer = tr->current_trace;
1154	int ret;
1155
1156	if (!type->selftest || tracing_selftest_disabled)
1157		return 0;
1158
1159	/*
1160	 * Run a selftest on this tracer.
1161	 * Here we reset the trace buffer, and set the current
1162	 * tracer to be this tracer. The tracer can then run some
1163	 * internal tracing to verify that everything is in order.
1164	 * If we fail, we do not register this tracer.
1165	 */
1166	tracing_reset_online_cpus(&tr->trace_buffer);
1167
1168	tr->current_trace = type;
1169
1170#ifdef CONFIG_TRACER_MAX_TRACE
1171	if (type->use_max_tr) {
1172		/* If we expanded the buffers, make sure the max is expanded too */
1173		if (ring_buffer_expanded)
1174			ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1175					   RING_BUFFER_ALL_CPUS);
1176		tr->allocated_snapshot = true;
1177	}
1178#endif
1179
1180	/* the test is responsible for initializing and enabling */
1181	pr_info("Testing tracer %s: ", type->name);
1182	ret = type->selftest(type, tr);
1183	/* the test is responsible for resetting too */
1184	tr->current_trace = saved_tracer;
1185	if (ret) {
1186		printk(KERN_CONT "FAILED!\n");
1187		/* Add the warning after printing 'FAILED' */
1188		WARN_ON(1);
1189		return -1;
1190	}
1191	/* Only reset on passing, to avoid touching corrupted buffers */
1192	tracing_reset_online_cpus(&tr->trace_buffer);
1193
1194#ifdef CONFIG_TRACER_MAX_TRACE
1195	if (type->use_max_tr) {
1196		tr->allocated_snapshot = false;
1197
1198		/* Shrink the max buffer again */
1199		if (ring_buffer_expanded)
1200			ring_buffer_resize(tr->max_buffer.buffer, 1,
1201					   RING_BUFFER_ALL_CPUS);
1202	}
1203#endif
1204
1205	printk(KERN_CONT "PASSED\n");
1206	return 0;
1207}
1208#else
1209static inline int run_tracer_selftest(struct tracer *type)
1210{
1211	return 0;
1212}
1213#endif /* CONFIG_FTRACE_STARTUP_TEST */
1214
1215static void add_tracer_options(struct trace_array *tr, struct tracer *t);
1216
1217static void __init apply_trace_boot_options(void);
1218
1219/**
1220 * register_tracer - register a tracer with the ftrace system.
1221 * @type - the plugin for the tracer
1222 *
1223 * Register a new plugin tracer.
1224 */
1225int __init register_tracer(struct tracer *type)
1226{
1227	struct tracer *t;
1228	int ret = 0;
1229
1230	if (!type->name) {
1231		pr_info("Tracer must have a name\n");
1232		return -1;
1233	}
1234
1235	if (strlen(type->name) >= MAX_TRACER_SIZE) {
1236		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1237		return -1;
1238	}
1239
1240	mutex_lock(&trace_types_lock);
1241
1242	tracing_selftest_running = true;
1243
1244	for (t = trace_types; t; t = t->next) {
1245		if (strcmp(type->name, t->name) == 0) {
1246			/* already found */
1247			pr_info("Tracer %s already registered\n",
1248				type->name);
1249			ret = -1;
1250			goto out;
1251		}
1252	}
1253
1254	if (!type->set_flag)
1255		type->set_flag = &dummy_set_flag;
1256	if (!type->flags) {
1257		/*allocate a dummy tracer_flags*/
1258		type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
1259		if (!type->flags) {
1260			ret = -ENOMEM;
1261			goto out;
1262		}
1263		type->flags->val = 0;
1264		type->flags->opts = dummy_tracer_opt;
1265	} else
1266		if (!type->flags->opts)
1267			type->flags->opts = dummy_tracer_opt;
 
 
1268
1269	/* store the tracer for __set_tracer_option */
1270	type->flags->trace = type;
1271
1272	ret = run_tracer_selftest(type);
1273	if (ret < 0)
1274		goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1275
1276	type->next = trace_types;
1277	trace_types = type;
1278	add_tracer_options(&global_trace, type);
1279
1280 out:
1281	tracing_selftest_running = false;
1282	mutex_unlock(&trace_types_lock);
1283
1284	if (ret || !default_bootup_tracer)
1285		goto out_unlock;
1286
1287	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1288		goto out_unlock;
1289
1290	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1291	/* Do we want this tracer to start on bootup? */
1292	tracing_set_tracer(&global_trace, type->name);
1293	default_bootup_tracer = NULL;
1294
1295	apply_trace_boot_options();
1296
1297	/* disable other selftests, since this will break it. */
1298	tracing_selftest_disabled = true;
1299#ifdef CONFIG_FTRACE_STARTUP_TEST
1300	printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1301	       type->name);
1302#endif
1303
1304 out_unlock:
1305	return ret;
1306}
1307
1308void tracing_reset(struct trace_buffer *buf, int cpu)
1309{
1310	struct ring_buffer *buffer = buf->buffer;
1311
1312	if (!buffer)
1313		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1314
1315	ring_buffer_record_disable(buffer);
1316
1317	/* Make sure all commits have finished */
1318	synchronize_sched();
1319	ring_buffer_reset_cpu(buffer, cpu);
1320
1321	ring_buffer_record_enable(buffer);
1322}
1323
1324void tracing_reset_online_cpus(struct trace_buffer *buf)
1325{
1326	struct ring_buffer *buffer = buf->buffer;
1327	int cpu;
1328
1329	if (!buffer)
1330		return;
1331
1332	ring_buffer_record_disable(buffer);
1333
1334	/* Make sure all commits have finished */
1335	synchronize_sched();
1336
1337	buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1338
1339	for_each_online_cpu(cpu)
1340		ring_buffer_reset_cpu(buffer, cpu);
1341
1342	ring_buffer_record_enable(buffer);
1343}
1344
1345/* Must have trace_types_lock held */
1346void tracing_reset_all_online_cpus(void)
1347{
1348	struct trace_array *tr;
 
1349
1350	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1351		tracing_reset_online_cpus(&tr->trace_buffer);
1352#ifdef CONFIG_TRACER_MAX_TRACE
1353		tracing_reset_online_cpus(&tr->max_buffer);
1354#endif
1355	}
1356}
1357
1358#define SAVED_CMDLINES_DEFAULT 128
1359#define NO_CMDLINE_MAP UINT_MAX
 
 
 
 
1360static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1361struct saved_cmdlines_buffer {
1362	unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1363	unsigned *map_cmdline_to_pid;
1364	unsigned cmdline_num;
1365	int cmdline_idx;
1366	char *saved_cmdlines;
1367};
1368static struct saved_cmdlines_buffer *savedcmd;
1369
1370/* temporary disable recording */
1371static atomic_t trace_record_cmdline_disabled __read_mostly;
1372
1373static inline char *get_saved_cmdlines(int idx)
1374{
1375	return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
 
 
1376}
1377
1378static inline void set_cmdline(int idx, const char *cmdline)
1379{
1380	memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
1381}
1382
1383static int allocate_cmdlines_buffer(unsigned int val,
1384				    struct saved_cmdlines_buffer *s)
1385{
1386	s->map_cmdline_to_pid = kmalloc(val * sizeof(*s->map_cmdline_to_pid),
1387					GFP_KERNEL);
1388	if (!s->map_cmdline_to_pid)
1389		return -ENOMEM;
1390
1391	s->saved_cmdlines = kmalloc(val * TASK_COMM_LEN, GFP_KERNEL);
1392	if (!s->saved_cmdlines) {
1393		kfree(s->map_cmdline_to_pid);
1394		return -ENOMEM;
1395	}
1396
1397	s->cmdline_idx = 0;
1398	s->cmdline_num = val;
1399	memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
1400	       sizeof(s->map_pid_to_cmdline));
1401	memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
1402	       val * sizeof(*s->map_cmdline_to_pid));
1403
1404	return 0;
1405}
1406
1407static int trace_create_savedcmd(void)
1408{
1409	int ret;
1410
1411	savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
1412	if (!savedcmd)
1413		return -ENOMEM;
1414
1415	ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
1416	if (ret < 0) {
1417		kfree(savedcmd);
1418		savedcmd = NULL;
1419		return -ENOMEM;
1420	}
1421
1422	return 0;
1423}
1424
1425int is_tracing_stopped(void)
1426{
1427	return global_trace.stop_count;
 
 
 
 
 
 
 
 
 
 
1428}
1429
1430/**
1431 * tracing_start - quick start of the tracer
1432 *
1433 * If tracing is enabled but was stopped by tracing_stop,
1434 * this will start the tracer back up.
1435 */
1436void tracing_start(void)
1437{
1438	struct ring_buffer *buffer;
1439	unsigned long flags;
1440
1441	if (tracing_disabled)
1442		return;
1443
1444	raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1445	if (--global_trace.stop_count) {
1446		if (global_trace.stop_count < 0) {
1447			/* Someone screwed up their debugging */
1448			WARN_ON_ONCE(1);
1449			global_trace.stop_count = 0;
1450		}
1451		goto out;
1452	}
1453
1454	/* Prevent the buffers from switching */
1455	arch_spin_lock(&global_trace.max_lock);
1456
1457	buffer = global_trace.trace_buffer.buffer;
1458	if (buffer)
1459		ring_buffer_record_enable(buffer);
1460
1461#ifdef CONFIG_TRACER_MAX_TRACE
1462	buffer = global_trace.max_buffer.buffer;
1463	if (buffer)
1464		ring_buffer_record_enable(buffer);
1465#endif
1466
1467	arch_spin_unlock(&global_trace.max_lock);
1468
 
1469 out:
1470	raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1471}
1472
1473static void tracing_start_tr(struct trace_array *tr)
1474{
1475	struct ring_buffer *buffer;
1476	unsigned long flags;
1477
1478	if (tracing_disabled)
1479		return;
1480
1481	/* If global, we need to also start the max tracer */
1482	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1483		return tracing_start();
1484
1485	raw_spin_lock_irqsave(&tr->start_lock, flags);
1486
1487	if (--tr->stop_count) {
1488		if (tr->stop_count < 0) {
1489			/* Someone screwed up their debugging */
1490			WARN_ON_ONCE(1);
1491			tr->stop_count = 0;
1492		}
1493		goto out;
1494	}
1495
1496	buffer = tr->trace_buffer.buffer;
1497	if (buffer)
1498		ring_buffer_record_enable(buffer);
1499
1500 out:
1501	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1502}
1503
1504/**
1505 * tracing_stop - quick stop of the tracer
1506 *
1507 * Light weight way to stop tracing. Use in conjunction with
1508 * tracing_start.
1509 */
1510void tracing_stop(void)
1511{
1512	struct ring_buffer *buffer;
1513	unsigned long flags;
1514
1515	raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1516	if (global_trace.stop_count++)
 
1517		goto out;
1518
1519	/* Prevent the buffers from switching */
1520	arch_spin_lock(&global_trace.max_lock);
1521
1522	buffer = global_trace.trace_buffer.buffer;
1523	if (buffer)
1524		ring_buffer_record_disable(buffer);
1525
1526#ifdef CONFIG_TRACER_MAX_TRACE
1527	buffer = global_trace.max_buffer.buffer;
1528	if (buffer)
1529		ring_buffer_record_disable(buffer);
1530#endif
1531
1532	arch_spin_unlock(&global_trace.max_lock);
1533
1534 out:
1535	raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1536}
1537
1538static void tracing_stop_tr(struct trace_array *tr)
1539{
1540	struct ring_buffer *buffer;
1541	unsigned long flags;
1542
1543	/* If global, we need to also stop the max tracer */
1544	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1545		return tracing_stop();
1546
1547	raw_spin_lock_irqsave(&tr->start_lock, flags);
1548	if (tr->stop_count++)
1549		goto out;
1550
1551	buffer = tr->trace_buffer.buffer;
1552	if (buffer)
1553		ring_buffer_record_disable(buffer);
1554
1555 out:
1556	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1557}
1558
1559void trace_stop_cmdline_recording(void);
1560
1561static int trace_save_cmdline(struct task_struct *tsk)
1562{
1563	unsigned pid, idx;
1564
1565	if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1566		return 0;
1567
1568	/*
1569	 * It's not the end of the world if we don't get
1570	 * the lock, but we also don't want to spin
1571	 * nor do we want to disable interrupts,
1572	 * so if we miss here, then better luck next time.
1573	 */
1574	if (!arch_spin_trylock(&trace_cmdline_lock))
1575		return 0;
1576
1577	idx = savedcmd->map_pid_to_cmdline[tsk->pid];
1578	if (idx == NO_CMDLINE_MAP) {
1579		idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
1580
1581		/*
1582		 * Check whether the cmdline buffer at idx has a pid
1583		 * mapped. We are going to overwrite that entry so we
1584		 * need to clear the map_pid_to_cmdline. Otherwise we
1585		 * would read the new comm for the old pid.
1586		 */
1587		pid = savedcmd->map_cmdline_to_pid[idx];
1588		if (pid != NO_CMDLINE_MAP)
1589			savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1590
1591		savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
1592		savedcmd->map_pid_to_cmdline[tsk->pid] = idx;
1593
1594		savedcmd->cmdline_idx = idx;
1595	}
1596
1597	set_cmdline(idx, tsk->comm);
1598
1599	arch_spin_unlock(&trace_cmdline_lock);
1600
1601	return 1;
1602}
1603
1604static void __trace_find_cmdline(int pid, char comm[])
1605{
1606	unsigned map;
1607
1608	if (!pid) {
1609		strcpy(comm, "<idle>");
1610		return;
1611	}
1612
1613	if (WARN_ON_ONCE(pid < 0)) {
1614		strcpy(comm, "<XXX>");
1615		return;
1616	}
1617
1618	if (pid > PID_MAX_DEFAULT) {
1619		strcpy(comm, "<...>");
1620		return;
1621	}
1622
1623	map = savedcmd->map_pid_to_cmdline[pid];
 
 
1624	if (map != NO_CMDLINE_MAP)
1625		strcpy(comm, get_saved_cmdlines(map));
1626	else
1627		strcpy(comm, "<...>");
1628}
1629
1630void trace_find_cmdline(int pid, char comm[])
1631{
1632	preempt_disable();
1633	arch_spin_lock(&trace_cmdline_lock);
1634
1635	__trace_find_cmdline(pid, comm);
1636
1637	arch_spin_unlock(&trace_cmdline_lock);
1638	preempt_enable();
1639}
1640
1641void tracing_record_cmdline(struct task_struct *tsk)
1642{
1643	if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
 
1644		return;
1645
1646	if (!__this_cpu_read(trace_cmdline_save))
1647		return;
1648
1649	if (trace_save_cmdline(tsk))
1650		__this_cpu_write(trace_cmdline_save, false);
1651}
1652
1653void
1654tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1655			     int pc)
1656{
1657	struct task_struct *tsk = current;
1658
1659	entry->preempt_count		= pc & 0xff;
1660	entry->pid			= (tsk) ? tsk->pid : 0;
 
1661	entry->flags =
1662#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1663		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1664#else
1665		TRACE_FLAG_IRQS_NOSUPPORT |
1666#endif
1667		((pc & NMI_MASK    ) ? TRACE_FLAG_NMI     : 0) |
1668		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1669		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1670		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
1671		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
1672}
1673EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1674
1675struct ring_buffer_event *
1676trace_buffer_lock_reserve(struct ring_buffer *buffer,
1677			  int type,
1678			  unsigned long len,
1679			  unsigned long flags, int pc)
1680{
1681	struct ring_buffer_event *event;
1682
1683	event = ring_buffer_lock_reserve(buffer, len);
1684	if (event != NULL) {
1685		struct trace_entry *ent = ring_buffer_event_data(event);
1686
1687		tracing_generic_entry_update(ent, flags, pc);
1688		ent->type = type;
1689	}
1690
1691	return event;
1692}
1693
1694void
1695__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
 
 
 
1696{
1697	__this_cpu_write(trace_cmdline_save, true);
1698	ring_buffer_unlock_commit(buffer, event);
1699}
1700
1701void trace_buffer_unlock_commit(struct trace_array *tr,
1702				struct ring_buffer *buffer,
1703				struct ring_buffer_event *event,
1704				unsigned long flags, int pc)
1705{
1706	__buffer_unlock_commit(buffer, event);
1707
1708	ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
1709	ftrace_trace_userstack(buffer, flags, pc);
1710}
1711EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit);
1712
1713static struct ring_buffer *temp_buffer;
 
 
1714
1715struct ring_buffer_event *
1716trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
1717			  struct trace_event_file *trace_file,
1718			  int type, unsigned long len,
1719			  unsigned long flags, int pc)
1720{
1721	struct ring_buffer_event *entry;
1722
1723	*current_rb = trace_file->tr->trace_buffer.buffer;
1724	entry = trace_buffer_lock_reserve(*current_rb,
1725					 type, len, flags, pc);
1726	/*
1727	 * If tracing is off, but we have triggers enabled
1728	 * we still need to look at the event data. Use the temp_buffer
1729	 * to store the trace event for the tigger to use. It's recusive
1730	 * safe and will not be recorded anywhere.
1731	 */
1732	if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
1733		*current_rb = temp_buffer;
1734		entry = trace_buffer_lock_reserve(*current_rb,
1735						  type, len, flags, pc);
1736	}
1737	return entry;
1738}
1739EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
1740
1741struct ring_buffer_event *
1742trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1743				  int type, unsigned long len,
1744				  unsigned long flags, int pc)
1745{
1746	*current_rb = global_trace.trace_buffer.buffer;
1747	return trace_buffer_lock_reserve(*current_rb,
1748					 type, len, flags, pc);
1749}
1750EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1751
1752void trace_buffer_unlock_commit_regs(struct trace_array *tr,
1753				     struct ring_buffer *buffer,
1754				     struct ring_buffer_event *event,
1755				     unsigned long flags, int pc,
1756				     struct pt_regs *regs)
1757{
1758	__buffer_unlock_commit(buffer, event);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1759
1760	ftrace_trace_stack(tr, buffer, flags, 0, pc, regs);
1761	ftrace_trace_userstack(buffer, flags, pc);
1762}
1763EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs);
1764
1765void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1766					 struct ring_buffer_event *event)
1767{
1768	ring_buffer_discard_commit(buffer, event);
1769}
1770EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1771
1772void
1773trace_function(struct trace_array *tr,
1774	       unsigned long ip, unsigned long parent_ip, unsigned long flags,
1775	       int pc)
1776{
1777	struct trace_event_call *call = &event_function;
1778	struct ring_buffer *buffer = tr->trace_buffer.buffer;
1779	struct ring_buffer_event *event;
1780	struct ftrace_entry *entry;
1781
 
 
 
 
1782	event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1783					  flags, pc);
1784	if (!event)
1785		return;
1786	entry	= ring_buffer_event_data(event);
1787	entry->ip			= ip;
1788	entry->parent_ip		= parent_ip;
1789
1790	if (!call_filter_check_discard(call, entry, buffer, event))
1791		__buffer_unlock_commit(buffer, event);
 
 
 
 
 
 
 
 
 
1792}
1793
1794#ifdef CONFIG_STACKTRACE
1795
1796#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1797struct ftrace_stack {
1798	unsigned long		calls[FTRACE_STACK_MAX_ENTRIES];
1799};
1800
1801static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1802static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1803
1804static void __ftrace_trace_stack(struct ring_buffer *buffer,
1805				 unsigned long flags,
1806				 int skip, int pc, struct pt_regs *regs)
1807{
1808	struct trace_event_call *call = &event_kernel_stack;
1809	struct ring_buffer_event *event;
1810	struct stack_entry *entry;
1811	struct stack_trace trace;
1812	int use_stack;
1813	int size = FTRACE_STACK_ENTRIES;
1814
1815	trace.nr_entries	= 0;
1816	trace.skip		= skip;
1817
1818	/*
1819	 * Since events can happen in NMIs there's no safe way to
1820	 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1821	 * or NMI comes in, it will just have to use the default
1822	 * FTRACE_STACK_SIZE.
1823	 */
1824	preempt_disable_notrace();
1825
1826	use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
1827	/*
1828	 * We don't need any atomic variables, just a barrier.
1829	 * If an interrupt comes in, we don't care, because it would
1830	 * have exited and put the counter back to what we want.
1831	 * We just need a barrier to keep gcc from moving things
1832	 * around.
1833	 */
1834	barrier();
1835	if (use_stack == 1) {
1836		trace.entries		= this_cpu_ptr(ftrace_stack.calls);
1837		trace.max_entries	= FTRACE_STACK_MAX_ENTRIES;
1838
1839		if (regs)
1840			save_stack_trace_regs(regs, &trace);
1841		else
1842			save_stack_trace(&trace);
1843
1844		if (trace.nr_entries > size)
1845			size = trace.nr_entries;
1846	} else
1847		/* From now on, use_stack is a boolean */
1848		use_stack = 0;
1849
1850	size *= sizeof(unsigned long);
1851
1852	event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1853					  sizeof(*entry) + size, flags, pc);
1854	if (!event)
1855		goto out;
1856	entry = ring_buffer_event_data(event);
1857
1858	memset(&entry->caller, 0, size);
1859
1860	if (use_stack)
1861		memcpy(&entry->caller, trace.entries,
1862		       trace.nr_entries * sizeof(unsigned long));
1863	else {
1864		trace.max_entries	= FTRACE_STACK_ENTRIES;
1865		trace.entries		= entry->caller;
1866		if (regs)
1867			save_stack_trace_regs(regs, &trace);
1868		else
1869			save_stack_trace(&trace);
1870	}
1871
1872	entry->size = trace.nr_entries;
1873
1874	if (!call_filter_check_discard(call, entry, buffer, event))
1875		__buffer_unlock_commit(buffer, event);
1876
1877 out:
1878	/* Again, don't let gcc optimize things here */
1879	barrier();
1880	__this_cpu_dec(ftrace_stack_reserve);
1881	preempt_enable_notrace();
1882
1883}
1884
1885static inline void ftrace_trace_stack(struct trace_array *tr,
1886				      struct ring_buffer *buffer,
1887				      unsigned long flags,
1888				      int skip, int pc, struct pt_regs *regs)
1889{
1890	if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
1891		return;
1892
1893	__ftrace_trace_stack(buffer, flags, skip, pc, regs);
1894}
1895
 
 
 
 
 
 
 
 
 
1896void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1897		   int pc)
1898{
1899	__ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
1900}
1901
1902/**
1903 * trace_dump_stack - record a stack back trace in the trace buffer
1904 * @skip: Number of functions to skip (helper handlers)
1905 */
1906void trace_dump_stack(int skip)
1907{
1908	unsigned long flags;
1909
1910	if (tracing_disabled || tracing_selftest_running)
1911		return;
1912
1913	local_save_flags(flags);
1914
1915	/*
1916	 * Skip 3 more, seems to get us at the caller of
1917	 * this function.
1918	 */
1919	skip += 3;
1920	__ftrace_trace_stack(global_trace.trace_buffer.buffer,
1921			     flags, skip, preempt_count(), NULL);
1922}
1923
1924static DEFINE_PER_CPU(int, user_stack_count);
1925
1926void
1927ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1928{
1929	struct trace_event_call *call = &event_user_stack;
1930	struct ring_buffer_event *event;
1931	struct userstack_entry *entry;
1932	struct stack_trace trace;
1933
1934	if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE))
1935		return;
1936
1937	/*
1938	 * NMIs can not handle page faults, even with fix ups.
1939	 * The save user stack can (and often does) fault.
1940	 */
1941	if (unlikely(in_nmi()))
1942		return;
1943
1944	/*
1945	 * prevent recursion, since the user stack tracing may
1946	 * trigger other kernel events.
1947	 */
1948	preempt_disable();
1949	if (__this_cpu_read(user_stack_count))
1950		goto out;
1951
1952	__this_cpu_inc(user_stack_count);
1953
1954	event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1955					  sizeof(*entry), flags, pc);
1956	if (!event)
1957		goto out_drop_count;
1958	entry	= ring_buffer_event_data(event);
1959
1960	entry->tgid		= current->tgid;
1961	memset(&entry->caller, 0, sizeof(entry->caller));
1962
1963	trace.nr_entries	= 0;
1964	trace.max_entries	= FTRACE_STACK_ENTRIES;
1965	trace.skip		= 0;
1966	trace.entries		= entry->caller;
1967
1968	save_stack_trace_user(&trace);
1969	if (!call_filter_check_discard(call, entry, buffer, event))
1970		__buffer_unlock_commit(buffer, event);
1971
1972 out_drop_count:
1973	__this_cpu_dec(user_stack_count);
1974 out:
1975	preempt_enable();
1976}
1977
1978#ifdef UNUSED
1979static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1980{
1981	ftrace_trace_userstack(tr, flags, preempt_count());
1982}
1983#endif /* UNUSED */
1984
1985#endif /* CONFIG_STACKTRACE */
1986
1987/* created for use with alloc_percpu */
1988struct trace_buffer_struct {
1989	char buffer[TRACE_BUF_SIZE];
1990};
1991
1992static struct trace_buffer_struct *trace_percpu_buffer;
1993static struct trace_buffer_struct *trace_percpu_sirq_buffer;
1994static struct trace_buffer_struct *trace_percpu_irq_buffer;
1995static struct trace_buffer_struct *trace_percpu_nmi_buffer;
1996
1997/*
1998 * The buffer used is dependent on the context. There is a per cpu
1999 * buffer for normal context, softirq contex, hard irq context and
2000 * for NMI context. Thise allows for lockless recording.
2001 *
2002 * Note, if the buffers failed to be allocated, then this returns NULL
2003 */
2004static char *get_trace_buf(void)
2005{
2006	struct trace_buffer_struct *percpu_buffer;
 
2007
2008	/*
2009	 * If we have allocated per cpu buffers, then we do not
2010	 * need to do any locking.
2011	 */
2012	if (in_nmi())
2013		percpu_buffer = trace_percpu_nmi_buffer;
2014	else if (in_irq())
2015		percpu_buffer = trace_percpu_irq_buffer;
2016	else if (in_softirq())
2017		percpu_buffer = trace_percpu_sirq_buffer;
2018	else
2019		percpu_buffer = trace_percpu_buffer;
2020
2021	if (!percpu_buffer)
2022		return NULL;
2023
2024	return this_cpu_ptr(&percpu_buffer->buffer[0]);
 
 
2025}
2026
2027static int alloc_percpu_trace_buffer(void)
2028{
2029	struct trace_buffer_struct *buffers;
2030	struct trace_buffer_struct *sirq_buffers;
2031	struct trace_buffer_struct *irq_buffers;
2032	struct trace_buffer_struct *nmi_buffers;
2033
2034	buffers = alloc_percpu(struct trace_buffer_struct);
2035	if (!buffers)
2036		goto err_warn;
2037
2038	sirq_buffers = alloc_percpu(struct trace_buffer_struct);
2039	if (!sirq_buffers)
2040		goto err_sirq;
2041
2042	irq_buffers = alloc_percpu(struct trace_buffer_struct);
2043	if (!irq_buffers)
2044		goto err_irq;
2045
2046	nmi_buffers = alloc_percpu(struct trace_buffer_struct);
2047	if (!nmi_buffers)
2048		goto err_nmi;
2049
2050	trace_percpu_buffer = buffers;
2051	trace_percpu_sirq_buffer = sirq_buffers;
2052	trace_percpu_irq_buffer = irq_buffers;
2053	trace_percpu_nmi_buffer = nmi_buffers;
2054
2055	return 0;
2056
2057 err_nmi:
2058	free_percpu(irq_buffers);
2059 err_irq:
2060	free_percpu(sirq_buffers);
2061 err_sirq:
2062	free_percpu(buffers);
2063 err_warn:
2064	WARN(1, "Could not allocate percpu trace_printk buffer");
2065	return -ENOMEM;
2066}
2067
2068static int buffers_allocated;
2069
2070void trace_printk_init_buffers(void)
2071{
 
 
2072	if (buffers_allocated)
2073		return;
2074
2075	if (alloc_percpu_trace_buffer())
2076		return;
2077
2078	/* trace_printk() is for debug use only. Don't use it in production. */
2079
2080	pr_warn("\n");
2081	pr_warn("**********************************************************\n");
2082	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
2083	pr_warn("**                                                      **\n");
2084	pr_warn("** trace_printk() being used. Allocating extra memory.  **\n");
2085	pr_warn("**                                                      **\n");
2086	pr_warn("** This means that this is a DEBUG kernel and it is     **\n");
2087	pr_warn("** unsafe for production use.                           **\n");
2088	pr_warn("**                                                      **\n");
2089	pr_warn("** If you see this message and you are not debugging    **\n");
2090	pr_warn("** the kernel, report this immediately to your vendor!  **\n");
2091	pr_warn("**                                                      **\n");
2092	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
2093	pr_warn("**********************************************************\n");
2094
2095	/* Expand the buffers to set size */
2096	tracing_update_buffers();
2097
2098	buffers_allocated = 1;
2099
2100	/*
2101	 * trace_printk_init_buffers() can be called by modules.
2102	 * If that happens, then we need to start cmdline recording
2103	 * directly here. If the global_trace.buffer is already
2104	 * allocated here, then this was called by module code.
2105	 */
2106	if (global_trace.trace_buffer.buffer)
2107		tracing_start_cmdline_record();
2108}
2109
2110void trace_printk_start_comm(void)
2111{
2112	/* Start tracing comms if trace printk is set */
2113	if (!buffers_allocated)
2114		return;
2115	tracing_start_cmdline_record();
2116}
2117
2118static void trace_printk_start_stop_comm(int enabled)
2119{
2120	if (!buffers_allocated)
2121		return;
2122
2123	if (enabled)
2124		tracing_start_cmdline_record();
2125	else
2126		tracing_stop_cmdline_record();
2127}
2128
2129/**
2130 * trace_vbprintk - write binary msg to tracing buffer
2131 *
2132 */
2133int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
2134{
2135	struct trace_event_call *call = &event_bprint;
2136	struct ring_buffer_event *event;
2137	struct ring_buffer *buffer;
2138	struct trace_array *tr = &global_trace;
2139	struct bprint_entry *entry;
2140	unsigned long flags;
2141	char *tbuffer;
2142	int len = 0, size, pc;
2143
2144	if (unlikely(tracing_selftest_running || tracing_disabled))
2145		return 0;
2146
2147	/* Don't pollute graph traces with trace_vprintk internals */
2148	pause_graph_tracing();
2149
2150	pc = preempt_count();
2151	preempt_disable_notrace();
2152
2153	tbuffer = get_trace_buf();
2154	if (!tbuffer) {
2155		len = 0;
2156		goto out;
2157	}
2158
2159	len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
2160
2161	if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
2162		goto out;
2163
2164	local_save_flags(flags);
2165	size = sizeof(*entry) + sizeof(u32) * len;
2166	buffer = tr->trace_buffer.buffer;
2167	event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
2168					  flags, pc);
2169	if (!event)
2170		goto out;
2171	entry = ring_buffer_event_data(event);
2172	entry->ip			= ip;
2173	entry->fmt			= fmt;
2174
2175	memcpy(entry->buf, tbuffer, sizeof(u32) * len);
2176	if (!call_filter_check_discard(call, entry, buffer, event)) {
2177		__buffer_unlock_commit(buffer, event);
2178		ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
2179	}
2180
2181out:
2182	preempt_enable_notrace();
2183	unpause_graph_tracing();
2184
2185	return len;
2186}
2187EXPORT_SYMBOL_GPL(trace_vbprintk);
2188
2189static int
2190__trace_array_vprintk(struct ring_buffer *buffer,
2191		      unsigned long ip, const char *fmt, va_list args)
2192{
2193	struct trace_event_call *call = &event_print;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2194	struct ring_buffer_event *event;
 
2195	int len = 0, size, pc;
2196	struct print_entry *entry;
2197	unsigned long flags;
2198	char *tbuffer;
2199
2200	if (tracing_disabled || tracing_selftest_running)
2201		return 0;
2202
2203	/* Don't pollute graph traces with trace_vprintk internals */
2204	pause_graph_tracing();
2205
2206	pc = preempt_count();
2207	preempt_disable_notrace();
2208
2209
2210	tbuffer = get_trace_buf();
2211	if (!tbuffer) {
2212		len = 0;
2213		goto out;
2214	}
2215
2216	len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
 
 
2217
2218	local_save_flags(flags);
2219	size = sizeof(*entry) + len + 1;
 
2220	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
2221					  flags, pc);
2222	if (!event)
2223		goto out;
2224	entry = ring_buffer_event_data(event);
2225	entry->ip = ip;
2226
2227	memcpy(&entry->buf, tbuffer, len + 1);
2228	if (!call_filter_check_discard(call, entry, buffer, event)) {
2229		__buffer_unlock_commit(buffer, event);
2230		ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
 
2231	}
2232 out:
2233	preempt_enable_notrace();
2234	unpause_graph_tracing();
2235
2236	return len;
2237}
2238
2239int trace_array_vprintk(struct trace_array *tr,
2240			unsigned long ip, const char *fmt, va_list args)
2241{
2242	return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
2243}
2244
2245int trace_array_printk(struct trace_array *tr,
2246		       unsigned long ip, const char *fmt, ...)
2247{
2248	int ret;
2249	va_list ap;
2250
2251	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
2252		return 0;
2253
2254	va_start(ap, fmt);
2255	ret = trace_array_vprintk(tr, ip, fmt, ap);
2256	va_end(ap);
2257	return ret;
2258}
2259
2260int trace_array_printk_buf(struct ring_buffer *buffer,
2261			   unsigned long ip, const char *fmt, ...)
2262{
2263	int ret;
2264	va_list ap;
2265
2266	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
2267		return 0;
2268
2269	va_start(ap, fmt);
2270	ret = __trace_array_vprintk(buffer, ip, fmt, ap);
2271	va_end(ap);
2272	return ret;
2273}
2274
2275int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
2276{
2277	return trace_array_vprintk(&global_trace, ip, fmt, args);
2278}
2279EXPORT_SYMBOL_GPL(trace_vprintk);
2280
2281static void trace_iterator_increment(struct trace_iterator *iter)
2282{
2283	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
2284
2285	iter->idx++;
2286	if (buf_iter)
2287		ring_buffer_read(buf_iter, NULL);
2288}
2289
2290static struct trace_entry *
2291peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
2292		unsigned long *lost_events)
2293{
2294	struct ring_buffer_event *event;
2295	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
2296
2297	if (buf_iter)
2298		event = ring_buffer_iter_peek(buf_iter, ts);
2299	else
2300		event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
2301					 lost_events);
2302
2303	if (event) {
2304		iter->ent_size = ring_buffer_event_length(event);
2305		return ring_buffer_event_data(event);
2306	}
2307	iter->ent_size = 0;
2308	return NULL;
2309}
2310
2311static struct trace_entry *
2312__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
2313		  unsigned long *missing_events, u64 *ent_ts)
2314{
2315	struct ring_buffer *buffer = iter->trace_buffer->buffer;
2316	struct trace_entry *ent, *next = NULL;
2317	unsigned long lost_events = 0, next_lost = 0;
2318	int cpu_file = iter->cpu_file;
2319	u64 next_ts = 0, ts;
2320	int next_cpu = -1;
2321	int next_size = 0;
2322	int cpu;
2323
2324	/*
2325	 * If we are in a per_cpu trace file, don't bother by iterating over
2326	 * all cpu and peek directly.
2327	 */
2328	if (cpu_file > RING_BUFFER_ALL_CPUS) {
2329		if (ring_buffer_empty_cpu(buffer, cpu_file))
2330			return NULL;
2331		ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
2332		if (ent_cpu)
2333			*ent_cpu = cpu_file;
2334
2335		return ent;
2336	}
2337
2338	for_each_tracing_cpu(cpu) {
2339
2340		if (ring_buffer_empty_cpu(buffer, cpu))
2341			continue;
2342
2343		ent = peek_next_entry(iter, cpu, &ts, &lost_events);
2344
2345		/*
2346		 * Pick the entry with the smallest timestamp:
2347		 */
2348		if (ent && (!next || ts < next_ts)) {
2349			next = ent;
2350			next_cpu = cpu;
2351			next_ts = ts;
2352			next_lost = lost_events;
2353			next_size = iter->ent_size;
2354		}
2355	}
2356
2357	iter->ent_size = next_size;
2358
2359	if (ent_cpu)
2360		*ent_cpu = next_cpu;
2361
2362	if (ent_ts)
2363		*ent_ts = next_ts;
2364
2365	if (missing_events)
2366		*missing_events = next_lost;
2367
2368	return next;
2369}
2370
2371/* Find the next real entry, without updating the iterator itself */
2372struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
2373					  int *ent_cpu, u64 *ent_ts)
2374{
2375	return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
2376}
2377
2378/* Find the next real entry, and increment the iterator to the next entry */
2379void *trace_find_next_entry_inc(struct trace_iterator *iter)
2380{
2381	iter->ent = __find_next_entry(iter, &iter->cpu,
2382				      &iter->lost_events, &iter->ts);
2383
2384	if (iter->ent)
2385		trace_iterator_increment(iter);
2386
2387	return iter->ent ? iter : NULL;
2388}
2389
2390static void trace_consume(struct trace_iterator *iter)
2391{
2392	ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
2393			    &iter->lost_events);
2394}
2395
2396static void *s_next(struct seq_file *m, void *v, loff_t *pos)
2397{
2398	struct trace_iterator *iter = m->private;
2399	int i = (int)*pos;
2400	void *ent;
2401
2402	WARN_ON_ONCE(iter->leftover);
2403
2404	(*pos)++;
2405
2406	/* can't go backwards */
2407	if (iter->idx > i)
2408		return NULL;
2409
2410	if (iter->idx < 0)
2411		ent = trace_find_next_entry_inc(iter);
2412	else
2413		ent = iter;
2414
2415	while (ent && iter->idx < i)
2416		ent = trace_find_next_entry_inc(iter);
2417
2418	iter->pos = *pos;
2419
2420	return ent;
2421}
2422
2423void tracing_iter_reset(struct trace_iterator *iter, int cpu)
2424{
 
2425	struct ring_buffer_event *event;
2426	struct ring_buffer_iter *buf_iter;
2427	unsigned long entries = 0;
2428	u64 ts;
2429
2430	per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
2431
2432	buf_iter = trace_buffer_iter(iter, cpu);
2433	if (!buf_iter)
2434		return;
2435
 
2436	ring_buffer_iter_reset(buf_iter);
2437
2438	/*
2439	 * We could have the case with the max latency tracers
2440	 * that a reset never took place on a cpu. This is evident
2441	 * by the timestamp being before the start of the buffer.
2442	 */
2443	while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
2444		if (ts >= iter->trace_buffer->time_start)
2445			break;
2446		entries++;
2447		ring_buffer_read(buf_iter, NULL);
2448	}
2449
2450	per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
2451}
2452
2453/*
2454 * The current tracer is copied to avoid a global locking
2455 * all around.
2456 */
2457static void *s_start(struct seq_file *m, loff_t *pos)
2458{
2459	struct trace_iterator *iter = m->private;
2460	struct trace_array *tr = iter->tr;
2461	int cpu_file = iter->cpu_file;
2462	void *p = NULL;
2463	loff_t l = 0;
2464	int cpu;
2465
2466	/*
2467	 * copy the tracer to avoid using a global lock all around.
2468	 * iter->trace is a copy of current_trace, the pointer to the
2469	 * name may be used instead of a strcmp(), as iter->trace->name
2470	 * will point to the same string as current_trace->name.
2471	 */
2472	mutex_lock(&trace_types_lock);
2473	if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
2474		*iter->trace = *tr->current_trace;
 
 
2475	mutex_unlock(&trace_types_lock);
2476
2477#ifdef CONFIG_TRACER_MAX_TRACE
2478	if (iter->snapshot && iter->trace->use_max_tr)
2479		return ERR_PTR(-EBUSY);
2480#endif
2481
2482	if (!iter->snapshot)
2483		atomic_inc(&trace_record_cmdline_disabled);
2484
2485	if (*pos != iter->pos) {
2486		iter->ent = NULL;
2487		iter->cpu = 0;
2488		iter->idx = -1;
2489
2490		if (cpu_file == RING_BUFFER_ALL_CPUS) {
2491			for_each_tracing_cpu(cpu)
2492				tracing_iter_reset(iter, cpu);
2493		} else
2494			tracing_iter_reset(iter, cpu_file);
2495
2496		iter->leftover = 0;
2497		for (p = iter; p && l < *pos; p = s_next(m, p, &l))
2498			;
2499
2500	} else {
2501		/*
2502		 * If we overflowed the seq_file before, then we want
2503		 * to just reuse the trace_seq buffer again.
2504		 */
2505		if (iter->leftover)
2506			p = iter;
2507		else {
2508			l = *pos - 1;
2509			p = s_next(m, p, &l);
2510		}
2511	}
2512
2513	trace_event_read_lock();
2514	trace_access_lock(cpu_file);
2515	return p;
2516}
2517
2518static void s_stop(struct seq_file *m, void *p)
2519{
2520	struct trace_iterator *iter = m->private;
2521
2522#ifdef CONFIG_TRACER_MAX_TRACE
2523	if (iter->snapshot && iter->trace->use_max_tr)
2524		return;
2525#endif
2526
2527	if (!iter->snapshot)
2528		atomic_dec(&trace_record_cmdline_disabled);
2529
2530	trace_access_unlock(iter->cpu_file);
2531	trace_event_read_unlock();
2532}
2533
2534static void
2535get_total_entries(struct trace_buffer *buf,
2536		  unsigned long *total, unsigned long *entries)
2537{
2538	unsigned long count;
2539	int cpu;
2540
2541	*total = 0;
2542	*entries = 0;
2543
2544	for_each_tracing_cpu(cpu) {
2545		count = ring_buffer_entries_cpu(buf->buffer, cpu);
2546		/*
2547		 * If this buffer has skipped entries, then we hold all
2548		 * entries for the trace and we need to ignore the
2549		 * ones before the time stamp.
2550		 */
2551		if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
2552			count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
2553			/* total is the same as the entries */
2554			*total += count;
2555		} else
2556			*total += count +
2557				ring_buffer_overrun_cpu(buf->buffer, cpu);
2558		*entries += count;
2559	}
2560}
2561
2562static void print_lat_help_header(struct seq_file *m)
2563{
2564	seq_puts(m, "#                  _------=> CPU#            \n"
2565		    "#                 / _-----=> irqs-off        \n"
2566		    "#                | / _----=> need-resched    \n"
2567		    "#                || / _---=> hardirq/softirq \n"
2568		    "#                ||| / _--=> preempt-depth   \n"
2569		    "#                |||| /     delay            \n"
2570		    "#  cmd     pid   ||||| time  |   caller      \n"
2571		    "#     \\   /      |||||  \\    |   /         \n");
2572}
2573
2574static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
2575{
2576	unsigned long total;
2577	unsigned long entries;
2578
2579	get_total_entries(buf, &total, &entries);
2580	seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu   #P:%d\n",
2581		   entries, total, num_online_cpus());
2582	seq_puts(m, "#\n");
2583}
2584
2585static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
2586{
2587	print_event_info(buf, m);
2588	seq_puts(m, "#           TASK-PID   CPU#      TIMESTAMP  FUNCTION\n"
2589		    "#              | |       |          |         |\n");
2590}
2591
2592static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
2593{
2594	print_event_info(buf, m);
2595	seq_puts(m, "#                              _-----=> irqs-off\n"
2596		    "#                             / _----=> need-resched\n"
2597		    "#                            | / _---=> hardirq/softirq\n"
2598		    "#                            || / _--=> preempt-depth\n"
2599		    "#                            ||| /     delay\n"
2600		    "#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION\n"
2601		    "#              | |       |   ||||       |         |\n");
2602}
2603
2604void
2605print_trace_header(struct seq_file *m, struct trace_iterator *iter)
2606{
2607	unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
2608	struct trace_buffer *buf = iter->trace_buffer;
2609	struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
2610	struct tracer *type = iter->trace;
2611	unsigned long entries;
2612	unsigned long total;
2613	const char *name = "preemption";
2614
2615	name = type->name;
 
2616
2617	get_total_entries(buf, &total, &entries);
2618
2619	seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
2620		   name, UTS_RELEASE);
2621	seq_puts(m, "# -----------------------------------"
2622		 "---------------------------------\n");
2623	seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2624		   " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2625		   nsecs_to_usecs(data->saved_latency),
2626		   entries,
2627		   total,
2628		   buf->cpu,
2629#if defined(CONFIG_PREEMPT_NONE)
2630		   "server",
2631#elif defined(CONFIG_PREEMPT_VOLUNTARY)
2632		   "desktop",
2633#elif defined(CONFIG_PREEMPT)
2634		   "preempt",
2635#else
2636		   "unknown",
2637#endif
2638		   /* These are reserved for later use */
2639		   0, 0, 0, 0);
2640#ifdef CONFIG_SMP
2641	seq_printf(m, " #P:%d)\n", num_online_cpus());
2642#else
2643	seq_puts(m, ")\n");
2644#endif
2645	seq_puts(m, "#    -----------------\n");
2646	seq_printf(m, "#    | task: %.16s-%d "
2647		   "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2648		   data->comm, data->pid,
2649		   from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
2650		   data->policy, data->rt_priority);
2651	seq_puts(m, "#    -----------------\n");
2652
2653	if (data->critical_start) {
2654		seq_puts(m, "#  => started at: ");
2655		seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
2656		trace_print_seq(m, &iter->seq);
2657		seq_puts(m, "\n#  => ended at:   ");
2658		seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
2659		trace_print_seq(m, &iter->seq);
2660		seq_puts(m, "\n#\n");
2661	}
2662
2663	seq_puts(m, "#\n");
2664}
2665
2666static void test_cpu_buff_start(struct trace_iterator *iter)
2667{
2668	struct trace_seq *s = &iter->seq;
2669	struct trace_array *tr = iter->tr;
2670
2671	if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
2672		return;
2673
2674	if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
2675		return;
2676
2677	if (iter->started && cpumask_test_cpu(iter->cpu, iter->started))
2678		return;
2679
2680	if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
2681		return;
2682
2683	if (iter->started)
2684		cpumask_set_cpu(iter->cpu, iter->started);
2685
2686	/* Don't print started cpu buffer for the first entry of the trace */
2687	if (iter->idx > 1)
2688		trace_seq_printf(s, "##### CPU %u buffer started ####\n",
2689				iter->cpu);
2690}
2691
2692static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
2693{
2694	struct trace_array *tr = iter->tr;
2695	struct trace_seq *s = &iter->seq;
2696	unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
2697	struct trace_entry *entry;
2698	struct trace_event *event;
2699
2700	entry = iter->ent;
2701
2702	test_cpu_buff_start(iter);
2703
2704	event = ftrace_find_event(entry->type);
2705
2706	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
2707		if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2708			trace_print_lat_context(iter);
2709		else
2710			trace_print_context(iter);
 
 
 
2711	}
2712
2713	if (trace_seq_has_overflowed(s))
2714		return TRACE_TYPE_PARTIAL_LINE;
2715
2716	if (event)
2717		return event->funcs->trace(iter, sym_flags, event);
2718
2719	trace_seq_printf(s, "Unknown type %d\n", entry->type);
 
2720
2721	return trace_handle_return(s);
 
 
2722}
2723
2724static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2725{
2726	struct trace_array *tr = iter->tr;
2727	struct trace_seq *s = &iter->seq;
2728	struct trace_entry *entry;
2729	struct trace_event *event;
2730
2731	entry = iter->ent;
2732
2733	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
2734		trace_seq_printf(s, "%d %d %llu ",
2735				 entry->pid, iter->cpu, iter->ts);
2736
2737	if (trace_seq_has_overflowed(s))
2738		return TRACE_TYPE_PARTIAL_LINE;
2739
2740	event = ftrace_find_event(entry->type);
2741	if (event)
2742		return event->funcs->raw(iter, 0, event);
2743
2744	trace_seq_printf(s, "%d ?\n", entry->type);
 
2745
2746	return trace_handle_return(s);
 
 
2747}
2748
2749static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2750{
2751	struct trace_array *tr = iter->tr;
2752	struct trace_seq *s = &iter->seq;
2753	unsigned char newline = '\n';
2754	struct trace_entry *entry;
2755	struct trace_event *event;
2756
2757	entry = iter->ent;
2758
2759	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
2760		SEQ_PUT_HEX_FIELD(s, entry->pid);
2761		SEQ_PUT_HEX_FIELD(s, iter->cpu);
2762		SEQ_PUT_HEX_FIELD(s, iter->ts);
2763		if (trace_seq_has_overflowed(s))
2764			return TRACE_TYPE_PARTIAL_LINE;
2765	}
2766
2767	event = ftrace_find_event(entry->type);
2768	if (event) {
2769		enum print_line_t ret = event->funcs->hex(iter, 0, event);
2770		if (ret != TRACE_TYPE_HANDLED)
2771			return ret;
2772	}
2773
2774	SEQ_PUT_FIELD(s, newline);
2775
2776	return trace_handle_return(s);
2777}
2778
2779static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2780{
2781	struct trace_array *tr = iter->tr;
2782	struct trace_seq *s = &iter->seq;
2783	struct trace_entry *entry;
2784	struct trace_event *event;
2785
2786	entry = iter->ent;
2787
2788	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
2789		SEQ_PUT_FIELD(s, entry->pid);
2790		SEQ_PUT_FIELD(s, iter->cpu);
2791		SEQ_PUT_FIELD(s, iter->ts);
2792		if (trace_seq_has_overflowed(s))
2793			return TRACE_TYPE_PARTIAL_LINE;
2794	}
2795
2796	event = ftrace_find_event(entry->type);
2797	return event ? event->funcs->binary(iter, 0, event) :
2798		TRACE_TYPE_HANDLED;
2799}
2800
2801int trace_empty(struct trace_iterator *iter)
2802{
2803	struct ring_buffer_iter *buf_iter;
2804	int cpu;
2805
2806	/* If we are looking at one CPU buffer, only check that one */
2807	if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
2808		cpu = iter->cpu_file;
2809		buf_iter = trace_buffer_iter(iter, cpu);
2810		if (buf_iter) {
2811			if (!ring_buffer_iter_empty(buf_iter))
2812				return 0;
2813		} else {
2814			if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2815				return 0;
2816		}
2817		return 1;
2818	}
2819
2820	for_each_tracing_cpu(cpu) {
2821		buf_iter = trace_buffer_iter(iter, cpu);
2822		if (buf_iter) {
2823			if (!ring_buffer_iter_empty(buf_iter))
2824				return 0;
2825		} else {
2826			if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2827				return 0;
2828		}
2829	}
2830
2831	return 1;
2832}
2833
2834/*  Called with trace_event_read_lock() held. */
2835enum print_line_t print_trace_line(struct trace_iterator *iter)
2836{
2837	struct trace_array *tr = iter->tr;
2838	unsigned long trace_flags = tr->trace_flags;
2839	enum print_line_t ret;
2840
2841	if (iter->lost_events) {
2842		trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2843				 iter->cpu, iter->lost_events);
2844		if (trace_seq_has_overflowed(&iter->seq))
2845			return TRACE_TYPE_PARTIAL_LINE;
2846	}
2847
2848	if (iter->trace && iter->trace->print_line) {
2849		ret = iter->trace->print_line(iter);
2850		if (ret != TRACE_TYPE_UNHANDLED)
2851			return ret;
2852	}
2853
2854	if (iter->ent->type == TRACE_BPUTS &&
2855			trace_flags & TRACE_ITER_PRINTK &&
2856			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2857		return trace_print_bputs_msg_only(iter);
2858
2859	if (iter->ent->type == TRACE_BPRINT &&
2860			trace_flags & TRACE_ITER_PRINTK &&
2861			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2862		return trace_print_bprintk_msg_only(iter);
2863
2864	if (iter->ent->type == TRACE_PRINT &&
2865			trace_flags & TRACE_ITER_PRINTK &&
2866			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2867		return trace_print_printk_msg_only(iter);
2868
2869	if (trace_flags & TRACE_ITER_BIN)
2870		return print_bin_fmt(iter);
2871
2872	if (trace_flags & TRACE_ITER_HEX)
2873		return print_hex_fmt(iter);
2874
2875	if (trace_flags & TRACE_ITER_RAW)
2876		return print_raw_fmt(iter);
2877
2878	return print_trace_fmt(iter);
2879}
2880
2881void trace_latency_header(struct seq_file *m)
2882{
2883	struct trace_iterator *iter = m->private;
2884	struct trace_array *tr = iter->tr;
2885
2886	/* print nothing if the buffers are empty */
2887	if (trace_empty(iter))
2888		return;
2889
2890	if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2891		print_trace_header(m, iter);
2892
2893	if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
2894		print_lat_help_header(m);
2895}
2896
2897void trace_default_header(struct seq_file *m)
2898{
2899	struct trace_iterator *iter = m->private;
2900	struct trace_array *tr = iter->tr;
2901	unsigned long trace_flags = tr->trace_flags;
2902
2903	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2904		return;
2905
2906	if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2907		/* print nothing if the buffers are empty */
2908		if (trace_empty(iter))
2909			return;
2910		print_trace_header(m, iter);
2911		if (!(trace_flags & TRACE_ITER_VERBOSE))
2912			print_lat_help_header(m);
2913	} else {
2914		if (!(trace_flags & TRACE_ITER_VERBOSE)) {
2915			if (trace_flags & TRACE_ITER_IRQ_INFO)
2916				print_func_help_header_irq(iter->trace_buffer, m);
2917			else
2918				print_func_help_header(iter->trace_buffer, m);
2919		}
2920	}
2921}
2922
2923static void test_ftrace_alive(struct seq_file *m)
2924{
2925	if (!ftrace_is_dead())
2926		return;
2927	seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
2928		    "#          MAY BE MISSING FUNCTION EVENTS\n");
2929}
2930
2931#ifdef CONFIG_TRACER_MAX_TRACE
2932static void show_snapshot_main_help(struct seq_file *m)
2933{
2934	seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
2935		    "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
2936		    "#                      Takes a snapshot of the main buffer.\n"
2937		    "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
2938		    "#                      (Doesn't have to be '2' works with any number that\n"
2939		    "#                       is not a '0' or '1')\n");
2940}
2941
2942static void show_snapshot_percpu_help(struct seq_file *m)
2943{
2944	seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2945#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2946	seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
2947		    "#                      Takes a snapshot of the main buffer for this cpu.\n");
2948#else
2949	seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
2950		    "#                     Must use main snapshot file to allocate.\n");
2951#endif
2952	seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
2953		    "#                      (Doesn't have to be '2' works with any number that\n"
2954		    "#                       is not a '0' or '1')\n");
2955}
2956
2957static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
2958{
2959	if (iter->tr->allocated_snapshot)
2960		seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
2961	else
2962		seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
2963
2964	seq_puts(m, "# Snapshot commands:\n");
2965	if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
2966		show_snapshot_main_help(m);
2967	else
2968		show_snapshot_percpu_help(m);
2969}
2970#else
2971/* Should never be called */
2972static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
2973#endif
2974
2975static int s_show(struct seq_file *m, void *v)
2976{
2977	struct trace_iterator *iter = v;
2978	int ret;
2979
2980	if (iter->ent == NULL) {
2981		if (iter->tr) {
2982			seq_printf(m, "# tracer: %s\n", iter->trace->name);
2983			seq_puts(m, "#\n");
2984			test_ftrace_alive(m);
2985		}
2986		if (iter->snapshot && trace_empty(iter))
2987			print_snapshot_help(m, iter);
2988		else if (iter->trace && iter->trace->print_header)
2989			iter->trace->print_header(m);
2990		else
2991			trace_default_header(m);
2992
2993	} else if (iter->leftover) {
2994		/*
2995		 * If we filled the seq_file buffer earlier, we
2996		 * want to just show it now.
2997		 */
2998		ret = trace_print_seq(m, &iter->seq);
2999
3000		/* ret should this time be zero, but you never know */
3001		iter->leftover = ret;
3002
3003	} else {
3004		print_trace_line(iter);
3005		ret = trace_print_seq(m, &iter->seq);
3006		/*
3007		 * If we overflow the seq_file buffer, then it will
3008		 * ask us for this data again at start up.
3009		 * Use that instead.
3010		 *  ret is 0 if seq_file write succeeded.
3011		 *        -1 otherwise.
3012		 */
3013		iter->leftover = ret;
3014	}
3015
3016	return 0;
3017}
3018
3019/*
3020 * Should be used after trace_array_get(), trace_types_lock
3021 * ensures that i_cdev was already initialized.
3022 */
3023static inline int tracing_get_cpu(struct inode *inode)
3024{
3025	if (inode->i_cdev) /* See trace_create_cpu_file() */
3026		return (long)inode->i_cdev - 1;
3027	return RING_BUFFER_ALL_CPUS;
3028}
3029
3030static const struct seq_operations tracer_seq_ops = {
3031	.start		= s_start,
3032	.next		= s_next,
3033	.stop		= s_stop,
3034	.show		= s_show,
3035};
3036
3037static struct trace_iterator *
3038__tracing_open(struct inode *inode, struct file *file, bool snapshot)
3039{
3040	struct trace_array *tr = inode->i_private;
3041	struct trace_iterator *iter;
3042	int cpu;
3043
3044	if (tracing_disabled)
3045		return ERR_PTR(-ENODEV);
3046
3047	iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
3048	if (!iter)
3049		return ERR_PTR(-ENOMEM);
3050
3051	iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
3052				    GFP_KERNEL);
3053	if (!iter->buffer_iter)
3054		goto release;
3055
3056	/*
3057	 * We make a copy of the current tracer to avoid concurrent
3058	 * changes on it while we are reading.
3059	 */
3060	mutex_lock(&trace_types_lock);
3061	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
3062	if (!iter->trace)
3063		goto fail;
3064
3065	*iter->trace = *tr->current_trace;
 
3066
3067	if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
3068		goto fail;
3069
3070	iter->tr = tr;
3071
3072#ifdef CONFIG_TRACER_MAX_TRACE
3073	/* Currently only the top directory has a snapshot */
3074	if (tr->current_trace->print_max || snapshot)
3075		iter->trace_buffer = &tr->max_buffer;
3076	else
3077#endif
3078		iter->trace_buffer = &tr->trace_buffer;
3079	iter->snapshot = snapshot;
3080	iter->pos = -1;
3081	iter->cpu_file = tracing_get_cpu(inode);
3082	mutex_init(&iter->mutex);
 
3083
3084	/* Notify the tracer early; before we stop tracing. */
3085	if (iter->trace && iter->trace->open)
3086		iter->trace->open(iter);
3087
3088	/* Annotate start of buffers if we had overruns */
3089	if (ring_buffer_overruns(iter->trace_buffer->buffer))
3090		iter->iter_flags |= TRACE_FILE_ANNOTATE;
3091
3092	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
3093	if (trace_clocks[tr->clock_id].in_ns)
3094		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
3095
3096	/* stop the trace while dumping if we are not opening "snapshot" */
3097	if (!iter->snapshot)
3098		tracing_stop_tr(tr);
3099
3100	if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
3101		for_each_tracing_cpu(cpu) {
3102			iter->buffer_iter[cpu] =
3103				ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3104		}
3105		ring_buffer_read_prepare_sync();
3106		for_each_tracing_cpu(cpu) {
3107			ring_buffer_read_start(iter->buffer_iter[cpu]);
3108			tracing_iter_reset(iter, cpu);
3109		}
3110	} else {
3111		cpu = iter->cpu_file;
3112		iter->buffer_iter[cpu] =
3113			ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3114		ring_buffer_read_prepare_sync();
3115		ring_buffer_read_start(iter->buffer_iter[cpu]);
3116		tracing_iter_reset(iter, cpu);
3117	}
3118
3119	mutex_unlock(&trace_types_lock);
3120
3121	return iter;
3122
3123 fail:
3124	mutex_unlock(&trace_types_lock);
3125	kfree(iter->trace);
3126	kfree(iter->buffer_iter);
3127release:
3128	seq_release_private(inode, file);
3129	return ERR_PTR(-ENOMEM);
3130}
3131
3132int tracing_open_generic(struct inode *inode, struct file *filp)
3133{
3134	if (tracing_disabled)
3135		return -ENODEV;
3136
3137	filp->private_data = inode->i_private;
3138	return 0;
3139}
3140
3141bool tracing_is_disabled(void)
3142{
3143	return (tracing_disabled) ? true: false;
3144}
3145
3146/*
3147 * Open and update trace_array ref count.
3148 * Must have the current trace_array passed to it.
3149 */
3150static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
3151{
3152	struct trace_array *tr = inode->i_private;
3153
3154	if (tracing_disabled)
3155		return -ENODEV;
3156
3157	if (trace_array_get(tr) < 0)
3158		return -ENODEV;
3159
3160	filp->private_data = inode->i_private;
3161
3162	return 0;
3163}
3164
3165static int tracing_release(struct inode *inode, struct file *file)
3166{
3167	struct trace_array *tr = inode->i_private;
3168	struct seq_file *m = file->private_data;
3169	struct trace_iterator *iter;
3170	int cpu;
3171
3172	if (!(file->f_mode & FMODE_READ)) {
3173		trace_array_put(tr);
3174		return 0;
3175	}
3176
3177	/* Writes do not use seq_file */
3178	iter = m->private;
3179	mutex_lock(&trace_types_lock);
3180
 
3181	for_each_tracing_cpu(cpu) {
3182		if (iter->buffer_iter[cpu])
3183			ring_buffer_read_finish(iter->buffer_iter[cpu]);
3184	}
3185
3186	if (iter->trace && iter->trace->close)
3187		iter->trace->close(iter);
3188
3189	if (!iter->snapshot)
3190		/* reenable tracing if it was previously enabled */
3191		tracing_start_tr(tr);
3192
3193	__trace_array_put(tr);
3194
3195	mutex_unlock(&trace_types_lock);
3196
3197	mutex_destroy(&iter->mutex);
3198	free_cpumask_var(iter->started);
3199	kfree(iter->trace);
3200	kfree(iter->buffer_iter);
3201	seq_release_private(inode, file);
3202
3203	return 0;
3204}
3205
3206static int tracing_release_generic_tr(struct inode *inode, struct file *file)
3207{
3208	struct trace_array *tr = inode->i_private;
3209
3210	trace_array_put(tr);
3211	return 0;
3212}
3213
3214static int tracing_single_release_tr(struct inode *inode, struct file *file)
3215{
3216	struct trace_array *tr = inode->i_private;
3217
3218	trace_array_put(tr);
3219
3220	return single_release(inode, file);
3221}
3222
3223static int tracing_open(struct inode *inode, struct file *file)
3224{
3225	struct trace_array *tr = inode->i_private;
3226	struct trace_iterator *iter;
3227	int ret = 0;
3228
3229	if (trace_array_get(tr) < 0)
3230		return -ENODEV;
3231
3232	/* If this file was open for write, then erase contents */
3233	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
3234		int cpu = tracing_get_cpu(inode);
 
3235
3236		if (cpu == RING_BUFFER_ALL_CPUS)
3237			tracing_reset_online_cpus(&tr->trace_buffer);
3238		else
3239			tracing_reset(&tr->trace_buffer, cpu);
3240	}
3241
3242	if (file->f_mode & FMODE_READ) {
3243		iter = __tracing_open(inode, file, false);
3244		if (IS_ERR(iter))
3245			ret = PTR_ERR(iter);
3246		else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
3247			iter->iter_flags |= TRACE_FILE_LAT_FMT;
3248	}
3249
3250	if (ret < 0)
3251		trace_array_put(tr);
3252
3253	return ret;
3254}
3255
3256/*
3257 * Some tracers are not suitable for instance buffers.
3258 * A tracer is always available for the global array (toplevel)
3259 * or if it explicitly states that it is.
3260 */
3261static bool
3262trace_ok_for_array(struct tracer *t, struct trace_array *tr)
3263{
3264	return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
3265}
3266
3267/* Find the next tracer that this trace array may use */
3268static struct tracer *
3269get_tracer_for_array(struct trace_array *tr, struct tracer *t)
3270{
3271	while (t && !trace_ok_for_array(t, tr))
3272		t = t->next;
3273
3274	return t;
3275}
3276
3277static void *
3278t_next(struct seq_file *m, void *v, loff_t *pos)
3279{
3280	struct trace_array *tr = m->private;
3281	struct tracer *t = v;
3282
3283	(*pos)++;
3284
3285	if (t)
3286		t = get_tracer_for_array(tr, t->next);
3287
3288	return t;
3289}
3290
3291static void *t_start(struct seq_file *m, loff_t *pos)
3292{
3293	struct trace_array *tr = m->private;
3294	struct tracer *t;
3295	loff_t l = 0;
3296
3297	mutex_lock(&trace_types_lock);
3298
3299	t = get_tracer_for_array(tr, trace_types);
3300	for (; t && l < *pos; t = t_next(m, t, &l))
3301			;
3302
3303	return t;
3304}
3305
3306static void t_stop(struct seq_file *m, void *p)
3307{
3308	mutex_unlock(&trace_types_lock);
3309}
3310
3311static int t_show(struct seq_file *m, void *v)
3312{
3313	struct tracer *t = v;
3314
3315	if (!t)
3316		return 0;
3317
3318	seq_puts(m, t->name);
3319	if (t->next)
3320		seq_putc(m, ' ');
3321	else
3322		seq_putc(m, '\n');
3323
3324	return 0;
3325}
3326
3327static const struct seq_operations show_traces_seq_ops = {
3328	.start		= t_start,
3329	.next		= t_next,
3330	.stop		= t_stop,
3331	.show		= t_show,
3332};
3333
3334static int show_traces_open(struct inode *inode, struct file *file)
3335{
3336	struct trace_array *tr = inode->i_private;
3337	struct seq_file *m;
3338	int ret;
3339
3340	if (tracing_disabled)
3341		return -ENODEV;
3342
3343	ret = seq_open(file, &show_traces_seq_ops);
3344	if (ret)
3345		return ret;
3346
3347	m = file->private_data;
3348	m->private = tr;
3349
3350	return 0;
3351}
3352
3353static ssize_t
3354tracing_write_stub(struct file *filp, const char __user *ubuf,
3355		   size_t count, loff_t *ppos)
3356{
3357	return count;
3358}
3359
3360loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
3361{
3362	int ret;
3363
3364	if (file->f_mode & FMODE_READ)
3365		ret = seq_lseek(file, offset, whence);
3366	else
3367		file->f_pos = ret = 0;
3368
3369	return ret;
3370}
3371
3372static const struct file_operations tracing_fops = {
3373	.open		= tracing_open,
3374	.read		= seq_read,
3375	.write		= tracing_write_stub,
3376	.llseek		= tracing_lseek,
3377	.release	= tracing_release,
3378};
3379
3380static const struct file_operations show_traces_fops = {
3381	.open		= show_traces_open,
3382	.read		= seq_read,
3383	.release	= seq_release,
3384	.llseek		= seq_lseek,
3385};
3386
3387/*
 
 
 
 
 
3388 * The tracer itself will not take this lock, but still we want
3389 * to provide a consistent cpumask to user-space:
3390 */
3391static DEFINE_MUTEX(tracing_cpumask_update_lock);
3392
3393/*
3394 * Temporary storage for the character representation of the
3395 * CPU bitmask (and one more byte for the newline):
3396 */
3397static char mask_str[NR_CPUS + 1];
3398
3399static ssize_t
3400tracing_cpumask_read(struct file *filp, char __user *ubuf,
3401		     size_t count, loff_t *ppos)
3402{
3403	struct trace_array *tr = file_inode(filp)->i_private;
3404	int len;
3405
3406	mutex_lock(&tracing_cpumask_update_lock);
3407
3408	len = snprintf(mask_str, count, "%*pb\n",
3409		       cpumask_pr_args(tr->tracing_cpumask));
3410	if (len >= count) {
3411		count = -EINVAL;
3412		goto out_err;
3413	}
 
3414	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
3415
3416out_err:
3417	mutex_unlock(&tracing_cpumask_update_lock);
3418
3419	return count;
3420}
3421
3422static ssize_t
3423tracing_cpumask_write(struct file *filp, const char __user *ubuf,
3424		      size_t count, loff_t *ppos)
3425{
3426	struct trace_array *tr = file_inode(filp)->i_private;
3427	cpumask_var_t tracing_cpumask_new;
3428	int err, cpu;
 
3429
3430	if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
3431		return -ENOMEM;
3432
3433	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
3434	if (err)
3435		goto err_unlock;
3436
3437	mutex_lock(&tracing_cpumask_update_lock);
3438
3439	local_irq_disable();
3440	arch_spin_lock(&tr->max_lock);
3441	for_each_tracing_cpu(cpu) {
3442		/*
3443		 * Increase/decrease the disabled counter if we are
3444		 * about to flip a bit in the cpumask:
3445		 */
3446		if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
3447				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3448			atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3449			ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
3450		}
3451		if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
3452				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3453			atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3454			ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
3455		}
3456	}
3457	arch_spin_unlock(&tr->max_lock);
3458	local_irq_enable();
3459
3460	cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
3461
3462	mutex_unlock(&tracing_cpumask_update_lock);
3463	free_cpumask_var(tracing_cpumask_new);
3464
3465	return count;
3466
3467err_unlock:
3468	free_cpumask_var(tracing_cpumask_new);
3469
3470	return err;
3471}
3472
3473static const struct file_operations tracing_cpumask_fops = {
3474	.open		= tracing_open_generic_tr,
3475	.read		= tracing_cpumask_read,
3476	.write		= tracing_cpumask_write,
3477	.release	= tracing_release_generic_tr,
3478	.llseek		= generic_file_llseek,
3479};
3480
3481static int tracing_trace_options_show(struct seq_file *m, void *v)
3482{
3483	struct tracer_opt *trace_opts;
3484	struct trace_array *tr = m->private;
3485	u32 tracer_flags;
3486	int i;
3487
3488	mutex_lock(&trace_types_lock);
3489	tracer_flags = tr->current_trace->flags->val;
3490	trace_opts = tr->current_trace->flags->opts;
3491
3492	for (i = 0; trace_options[i]; i++) {
3493		if (tr->trace_flags & (1 << i))
3494			seq_printf(m, "%s\n", trace_options[i]);
3495		else
3496			seq_printf(m, "no%s\n", trace_options[i]);
3497	}
3498
3499	for (i = 0; trace_opts[i].name; i++) {
3500		if (tracer_flags & trace_opts[i].bit)
3501			seq_printf(m, "%s\n", trace_opts[i].name);
3502		else
3503			seq_printf(m, "no%s\n", trace_opts[i].name);
3504	}
3505	mutex_unlock(&trace_types_lock);
3506
3507	return 0;
3508}
3509
3510static int __set_tracer_option(struct trace_array *tr,
3511			       struct tracer_flags *tracer_flags,
3512			       struct tracer_opt *opts, int neg)
3513{
3514	struct tracer *trace = tracer_flags->trace;
3515	int ret;
3516
3517	ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
3518	if (ret)
3519		return ret;
3520
3521	if (neg)
3522		tracer_flags->val &= ~opts->bit;
3523	else
3524		tracer_flags->val |= opts->bit;
3525	return 0;
3526}
3527
3528/* Try to assign a tracer specific option */
3529static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
3530{
3531	struct tracer *trace = tr->current_trace;
3532	struct tracer_flags *tracer_flags = trace->flags;
3533	struct tracer_opt *opts = NULL;
3534	int i;
3535
3536	for (i = 0; tracer_flags->opts[i].name; i++) {
3537		opts = &tracer_flags->opts[i];
3538
3539		if (strcmp(cmp, opts->name) == 0)
3540			return __set_tracer_option(tr, trace->flags, opts, neg);
 
3541	}
3542
3543	return -EINVAL;
3544}
3545
3546/* Some tracers require overwrite to stay enabled */
3547int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
3548{
3549	if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
3550		return -1;
3551
3552	return 0;
3553}
3554
3555int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
3556{
3557	/* do nothing if flag is already set */
3558	if (!!(tr->trace_flags & mask) == !!enabled)
3559		return 0;
3560
3561	/* Give the tracer a chance to approve the change */
3562	if (tr->current_trace->flag_changed)
3563		if (tr->current_trace->flag_changed(tr, mask, !!enabled))
3564			return -EINVAL;
3565
3566	if (enabled)
3567		tr->trace_flags |= mask;
3568	else
3569		tr->trace_flags &= ~mask;
3570
3571	if (mask == TRACE_ITER_RECORD_CMD)
3572		trace_event_enable_cmd_record(enabled);
3573
3574	if (mask == TRACE_ITER_OVERWRITE) {
3575		ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
3576#ifdef CONFIG_TRACER_MAX_TRACE
3577		ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
3578#endif
3579	}
3580
3581	if (mask == TRACE_ITER_PRINTK) {
3582		trace_printk_start_stop_comm(enabled);
3583		trace_printk_control(enabled);
3584	}
3585
3586	return 0;
3587}
3588
3589static int trace_set_options(struct trace_array *tr, char *option)
 
 
3590{
 
3591	char *cmp;
3592	int neg = 0;
3593	int ret = -ENODEV;
3594	int i;
3595	size_t orig_len = strlen(option);
3596
3597	cmp = strstrip(option);
 
 
 
 
 
 
 
3598
3599	if (strncmp(cmp, "no", 2) == 0) {
3600		neg = 1;
3601		cmp += 2;
3602	}
3603
3604	mutex_lock(&trace_types_lock);
3605
3606	for (i = 0; trace_options[i]; i++) {
3607		if (strcmp(cmp, trace_options[i]) == 0) {
3608			ret = set_tracer_flag(tr, 1 << i, !neg);
3609			break;
3610		}
3611	}
3612
3613	/* If no option could be set, test the specific tracer options */
3614	if (!trace_options[i])
3615		ret = set_tracer_option(tr, cmp, neg);
3616
3617	mutex_unlock(&trace_types_lock);
3618
3619	/*
3620	 * If the first trailing whitespace is replaced with '\0' by strstrip,
3621	 * turn it back into a space.
3622	 */
3623	if (orig_len > strlen(option))
3624		option[strlen(option)] = ' ';
3625
3626	return ret;
3627}
3628
3629static void __init apply_trace_boot_options(void)
3630{
3631	char *buf = trace_boot_options_buf;
3632	char *option;
3633
3634	while (true) {
3635		option = strsep(&buf, ",");
3636
3637		if (!option)
3638			break;
3639
3640		if (*option)
3641			trace_set_options(&global_trace, option);
3642
3643		/* Put back the comma to allow this to be called again */
3644		if (buf)
3645			*(buf - 1) = ',';
3646	}
3647}
3648
3649static ssize_t
3650tracing_trace_options_write(struct file *filp, const char __user *ubuf,
3651			size_t cnt, loff_t *ppos)
3652{
3653	struct seq_file *m = filp->private_data;
3654	struct trace_array *tr = m->private;
3655	char buf[64];
3656	int ret;
3657
3658	if (cnt >= sizeof(buf))
3659		return -EINVAL;
3660
3661	if (copy_from_user(&buf, ubuf, cnt))
3662		return -EFAULT;
3663
3664	buf[cnt] = 0;
3665
3666	ret = trace_set_options(tr, buf);
3667	if (ret < 0)
3668		return ret;
3669
3670	*ppos += cnt;
3671
3672	return cnt;
3673}
3674
3675static int tracing_trace_options_open(struct inode *inode, struct file *file)
3676{
3677	struct trace_array *tr = inode->i_private;
3678	int ret;
3679
3680	if (tracing_disabled)
3681		return -ENODEV;
3682
3683	if (trace_array_get(tr) < 0)
3684		return -ENODEV;
3685
3686	ret = single_open(file, tracing_trace_options_show, inode->i_private);
3687	if (ret < 0)
3688		trace_array_put(tr);
3689
3690	return ret;
3691}
3692
3693static const struct file_operations tracing_iter_fops = {
3694	.open		= tracing_trace_options_open,
3695	.read		= seq_read,
3696	.llseek		= seq_lseek,
3697	.release	= tracing_single_release_tr,
3698	.write		= tracing_trace_options_write,
3699};
3700
3701static const char readme_msg[] =
3702	"tracing mini-HOWTO:\n\n"
3703	"# echo 0 > tracing_on : quick way to disable tracing\n"
3704	"# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3705	" Important files:\n"
3706	"  trace\t\t\t- The static contents of the buffer\n"
3707	"\t\t\t  To clear the buffer write into this file: echo > trace\n"
3708	"  trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3709	"  current_tracer\t- function and latency tracers\n"
3710	"  available_tracers\t- list of configured tracers for current_tracer\n"
3711	"  buffer_size_kb\t- view and modify size of per cpu buffer\n"
3712	"  buffer_total_size_kb  - view total size of all cpu buffers\n\n"
3713	"  trace_clock\t\t-change the clock used to order events\n"
3714	"       local:   Per cpu clock but may not be synced across CPUs\n"
3715	"      global:   Synced across CPUs but slows tracing down.\n"
3716	"     counter:   Not a clock, but just an increment\n"
3717	"      uptime:   Jiffy counter from time of boot\n"
3718	"        perf:   Same clock that perf events use\n"
3719#ifdef CONFIG_X86_64
3720	"     x86-tsc:   TSC cycle counter\n"
3721#endif
3722	"\n  trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3723	"  tracing_cpumask\t- Limit which CPUs to trace\n"
3724	"  instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3725	"\t\t\t  Remove sub-buffer with rmdir\n"
3726	"  trace_options\t\t- Set format or modify how tracing happens\n"
3727	"\t\t\t  Disable an option by adding a suffix 'no' to the\n"
3728	"\t\t\t  option name\n"
3729	"  saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
3730#ifdef CONFIG_DYNAMIC_FTRACE
3731	"\n  available_filter_functions - list of functions that can be filtered on\n"
3732	"  set_ftrace_filter\t- echo function name in here to only trace these\n"
3733	"\t\t\t  functions\n"
3734	"\t     accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3735	"\t     modules: Can select a group via module\n"
3736	"\t      Format: :mod:<module-name>\n"
3737	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"
3738	"\t    triggers: a command to perform when function is hit\n"
3739	"\t      Format: <function>:<trigger>[:count]\n"
3740	"\t     trigger: traceon, traceoff\n"
3741	"\t\t      enable_event:<system>:<event>\n"
3742	"\t\t      disable_event:<system>:<event>\n"
3743#ifdef CONFIG_STACKTRACE
3744	"\t\t      stacktrace\n"
3745#endif
3746#ifdef CONFIG_TRACER_SNAPSHOT
3747	"\t\t      snapshot\n"
3748#endif
3749	"\t\t      dump\n"
3750	"\t\t      cpudump\n"
3751	"\t     example: echo do_fault:traceoff > set_ftrace_filter\n"
3752	"\t              echo do_trap:traceoff:3 > set_ftrace_filter\n"
3753	"\t     The first one will disable tracing every time do_fault is hit\n"
3754	"\t     The second will disable tracing at most 3 times when do_trap is hit\n"
3755	"\t       The first time do trap is hit and it disables tracing, the\n"
3756	"\t       counter will decrement to 2. If tracing is already disabled,\n"
3757	"\t       the counter will not decrement. It only decrements when the\n"
3758	"\t       trigger did work\n"
3759	"\t     To remove trigger without count:\n"
3760	"\t       echo '!<function>:<trigger> > set_ftrace_filter\n"
3761	"\t     To remove trigger with a count:\n"
3762	"\t       echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3763	"  set_ftrace_notrace\t- echo function name in here to never trace.\n"
3764	"\t    accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3765	"\t    modules: Can select a group via module command :mod:\n"
3766	"\t    Does not accept triggers\n"
3767#endif /* CONFIG_DYNAMIC_FTRACE */
3768#ifdef CONFIG_FUNCTION_TRACER
3769	"  set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
3770	"\t\t    (function)\n"
3771#endif
3772#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3773	"  set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3774	"  set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
3775	"  max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3776#endif
3777#ifdef CONFIG_TRACER_SNAPSHOT
3778	"\n  snapshot\t\t- Like 'trace' but shows the content of the static\n"
3779	"\t\t\t  snapshot buffer. Read the contents for more\n"
3780	"\t\t\t  information\n"
3781#endif
3782#ifdef CONFIG_STACK_TRACER
3783	"  stack_trace\t\t- Shows the max stack trace when active\n"
3784	"  stack_max_size\t- Shows current max stack size that was traced\n"
3785	"\t\t\t  Write into this file to reset the max size (trigger a\n"
3786	"\t\t\t  new trace)\n"
3787#ifdef CONFIG_DYNAMIC_FTRACE
3788	"  stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
3789	"\t\t\t  traces\n"
3790#endif
3791#endif /* CONFIG_STACK_TRACER */
3792	"  events/\t\t- Directory containing all trace event subsystems:\n"
3793	"      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
3794	"  events/<system>/\t- Directory containing all trace events for <system>:\n"
3795	"      enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
3796	"\t\t\t  events\n"
3797	"      filter\t\t- If set, only events passing filter are traced\n"
3798	"  events/<system>/<event>/\t- Directory containing control files for\n"
3799	"\t\t\t  <event>:\n"
3800	"      enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
3801	"      filter\t\t- If set, only events passing filter are traced\n"
3802	"      trigger\t\t- If set, a command to perform when event is hit\n"
3803	"\t    Format: <trigger>[:count][if <filter>]\n"
3804	"\t   trigger: traceon, traceoff\n"
3805	"\t            enable_event:<system>:<event>\n"
3806	"\t            disable_event:<system>:<event>\n"
3807#ifdef CONFIG_STACKTRACE
3808	"\t\t    stacktrace\n"
3809#endif
3810#ifdef CONFIG_TRACER_SNAPSHOT
3811	"\t\t    snapshot\n"
3812#endif
3813	"\t   example: echo traceoff > events/block/block_unplug/trigger\n"
3814	"\t            echo traceoff:3 > events/block/block_unplug/trigger\n"
3815	"\t            echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
3816	"\t                  events/block/block_unplug/trigger\n"
3817	"\t   The first disables tracing every time block_unplug is hit.\n"
3818	"\t   The second disables tracing the first 3 times block_unplug is hit.\n"
3819	"\t   The third enables the kmalloc event the first 3 times block_unplug\n"
3820	"\t     is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
3821	"\t   Like function triggers, the counter is only decremented if it\n"
3822	"\t    enabled or disabled tracing.\n"
3823	"\t   To remove a trigger without a count:\n"
3824	"\t     echo '!<trigger> > <system>/<event>/trigger\n"
3825	"\t   To remove a trigger with a count:\n"
3826	"\t     echo '!<trigger>:0 > <system>/<event>/trigger\n"
3827	"\t   Filters can be ignored when removing a trigger.\n"
3828;
3829
3830static ssize_t
3831tracing_readme_read(struct file *filp, char __user *ubuf,
3832		       size_t cnt, loff_t *ppos)
3833{
3834	return simple_read_from_buffer(ubuf, cnt, ppos,
3835					readme_msg, strlen(readme_msg));
3836}
3837
3838static const struct file_operations tracing_readme_fops = {
3839	.open		= tracing_open_generic,
3840	.read		= tracing_readme_read,
3841	.llseek		= generic_file_llseek,
3842};
3843
3844static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
 
 
3845{
3846	unsigned int *ptr = v;
3847
3848	if (*pos || m->count)
3849		ptr++;
3850
3851	(*pos)++;
3852
3853	for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
3854	     ptr++) {
3855		if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
3856			continue;
3857
3858		return ptr;
 
 
 
3859	}
3860
3861	return NULL;
3862}
3863
3864static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
3865{
3866	void *v;
3867	loff_t l = 0;
3868
3869	preempt_disable();
3870	arch_spin_lock(&trace_cmdline_lock);
 
3871
3872	v = &savedcmd->map_cmdline_to_pid[0];
3873	while (l <= *pos) {
3874		v = saved_cmdlines_next(m, v, &l);
3875		if (!v)
3876			return NULL;
3877	}
3878
3879	return v;
3880}
3881
3882static void saved_cmdlines_stop(struct seq_file *m, void *v)
3883{
3884	arch_spin_unlock(&trace_cmdline_lock);
3885	preempt_enable();
3886}
3887
3888static int saved_cmdlines_show(struct seq_file *m, void *v)
3889{
3890	char buf[TASK_COMM_LEN];
3891	unsigned int *pid = v;
3892
3893	__trace_find_cmdline(*pid, buf);
3894	seq_printf(m, "%d %s\n", *pid, buf);
3895	return 0;
3896}
3897
3898static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
3899	.start		= saved_cmdlines_start,
3900	.next		= saved_cmdlines_next,
3901	.stop		= saved_cmdlines_stop,
3902	.show		= saved_cmdlines_show,
3903};
3904
3905static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
3906{
3907	if (tracing_disabled)
3908		return -ENODEV;
3909
3910	return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
3911}
3912
3913static const struct file_operations tracing_saved_cmdlines_fops = {
3914	.open		= tracing_saved_cmdlines_open,
3915	.read		= seq_read,
3916	.llseek		= seq_lseek,
3917	.release	= seq_release,
3918};
3919
3920static ssize_t
3921tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
3922				 size_t cnt, loff_t *ppos)
3923{
3924	char buf[64];
3925	int r;
3926
3927	arch_spin_lock(&trace_cmdline_lock);
3928	r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
3929	arch_spin_unlock(&trace_cmdline_lock);
3930
3931	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3932}
3933
3934static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
3935{
3936	kfree(s->saved_cmdlines);
3937	kfree(s->map_cmdline_to_pid);
3938	kfree(s);
3939}
3940
3941static int tracing_resize_saved_cmdlines(unsigned int val)
3942{
3943	struct saved_cmdlines_buffer *s, *savedcmd_temp;
3944
3945	s = kmalloc(sizeof(*s), GFP_KERNEL);
3946	if (!s)
3947		return -ENOMEM;
3948
3949	if (allocate_cmdlines_buffer(val, s) < 0) {
3950		kfree(s);
3951		return -ENOMEM;
3952	}
3953
3954	arch_spin_lock(&trace_cmdline_lock);
3955	savedcmd_temp = savedcmd;
3956	savedcmd = s;
3957	arch_spin_unlock(&trace_cmdline_lock);
3958	free_saved_cmdlines_buffer(savedcmd_temp);
3959
3960	return 0;
3961}
3962
3963static ssize_t
3964tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
3965				  size_t cnt, loff_t *ppos)
3966{
 
3967	unsigned long val;
3968	int ret;
3969
3970	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3971	if (ret)
3972		return ret;
3973
3974	/* must have at least 1 entry or less than PID_MAX_DEFAULT */
3975	if (!val || val > PID_MAX_DEFAULT)
3976		return -EINVAL;
3977
3978	ret = tracing_resize_saved_cmdlines((unsigned int)val);
3979	if (ret < 0)
3980		return ret;
3981
3982	*ppos += cnt;
3983
3984	return cnt;
3985}
3986
3987static const struct file_operations tracing_saved_cmdlines_size_fops = {
3988	.open		= tracing_open_generic,
3989	.read		= tracing_saved_cmdlines_size_read,
3990	.write		= tracing_saved_cmdlines_size_write,
3991};
3992
3993#ifdef CONFIG_TRACE_ENUM_MAP_FILE
3994static union trace_enum_map_item *
3995update_enum_map(union trace_enum_map_item *ptr)
3996{
3997	if (!ptr->map.enum_string) {
3998		if (ptr->tail.next) {
3999			ptr = ptr->tail.next;
4000			/* Set ptr to the next real item (skip head) */
4001			ptr++;
4002		} else
4003			return NULL;
4004	}
4005	return ptr;
4006}
4007
4008static void *enum_map_next(struct seq_file *m, void *v, loff_t *pos)
4009{
4010	union trace_enum_map_item *ptr = v;
4011
4012	/*
4013	 * Paranoid! If ptr points to end, we don't want to increment past it.
4014	 * This really should never happen.
4015	 */
4016	ptr = update_enum_map(ptr);
4017	if (WARN_ON_ONCE(!ptr))
4018		return NULL;
4019
4020	ptr++;
4021
4022	(*pos)++;
4023
4024	ptr = update_enum_map(ptr);
4025
4026	return ptr;
4027}
4028
4029static void *enum_map_start(struct seq_file *m, loff_t *pos)
4030{
4031	union trace_enum_map_item *v;
4032	loff_t l = 0;
4033
4034	mutex_lock(&trace_enum_mutex);
4035
4036	v = trace_enum_maps;
4037	if (v)
4038		v++;
4039
4040	while (v && l < *pos) {
4041		v = enum_map_next(m, v, &l);
4042	}
4043
4044	return v;
4045}
4046
4047static void enum_map_stop(struct seq_file *m, void *v)
4048{
4049	mutex_unlock(&trace_enum_mutex);
4050}
4051
4052static int enum_map_show(struct seq_file *m, void *v)
4053{
4054	union trace_enum_map_item *ptr = v;
4055
4056	seq_printf(m, "%s %ld (%s)\n",
4057		   ptr->map.enum_string, ptr->map.enum_value,
4058		   ptr->map.system);
4059
4060	return 0;
4061}
4062
4063static const struct seq_operations tracing_enum_map_seq_ops = {
4064	.start		= enum_map_start,
4065	.next		= enum_map_next,
4066	.stop		= enum_map_stop,
4067	.show		= enum_map_show,
4068};
4069
4070static int tracing_enum_map_open(struct inode *inode, struct file *filp)
4071{
4072	if (tracing_disabled)
4073		return -ENODEV;
4074
4075	return seq_open(filp, &tracing_enum_map_seq_ops);
4076}
4077
4078static const struct file_operations tracing_enum_map_fops = {
4079	.open		= tracing_enum_map_open,
4080	.read		= seq_read,
4081	.llseek		= seq_lseek,
4082	.release	= seq_release,
4083};
4084
4085static inline union trace_enum_map_item *
4086trace_enum_jmp_to_tail(union trace_enum_map_item *ptr)
4087{
4088	/* Return tail of array given the head */
4089	return ptr + ptr->head.length + 1;
4090}
4091
4092static void
4093trace_insert_enum_map_file(struct module *mod, struct trace_enum_map **start,
4094			   int len)
4095{
4096	struct trace_enum_map **stop;
4097	struct trace_enum_map **map;
4098	union trace_enum_map_item *map_array;
4099	union trace_enum_map_item *ptr;
4100
4101	stop = start + len;
4102
4103	/*
4104	 * The trace_enum_maps contains the map plus a head and tail item,
4105	 * where the head holds the module and length of array, and the
4106	 * tail holds a pointer to the next list.
4107	 */
4108	map_array = kmalloc(sizeof(*map_array) * (len + 2), GFP_KERNEL);
4109	if (!map_array) {
4110		pr_warn("Unable to allocate trace enum mapping\n");
4111		return;
4112	}
4113
4114	mutex_lock(&trace_enum_mutex);
4115
4116	if (!trace_enum_maps)
4117		trace_enum_maps = map_array;
4118	else {
4119		ptr = trace_enum_maps;
4120		for (;;) {
4121			ptr = trace_enum_jmp_to_tail(ptr);
4122			if (!ptr->tail.next)
4123				break;
4124			ptr = ptr->tail.next;
4125
 
 
 
 
 
 
 
 
 
 
4126		}
4127		ptr->tail.next = map_array;
4128	}
4129	map_array->head.mod = mod;
4130	map_array->head.length = len;
4131	map_array++;
4132
4133	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
4134		map_array->map = **map;
4135		map_array++;
4136	}
4137	memset(map_array, 0, sizeof(*map_array));
4138
4139	mutex_unlock(&trace_enum_mutex);
4140}
4141
4142static void trace_create_enum_file(struct dentry *d_tracer)
4143{
4144	trace_create_file("enum_map", 0444, d_tracer,
4145			  NULL, &tracing_enum_map_fops);
4146}
4147
4148#else /* CONFIG_TRACE_ENUM_MAP_FILE */
4149static inline void trace_create_enum_file(struct dentry *d_tracer) { }
4150static inline void trace_insert_enum_map_file(struct module *mod,
4151			      struct trace_enum_map **start, int len) { }
4152#endif /* !CONFIG_TRACE_ENUM_MAP_FILE */
4153
4154static void trace_insert_enum_map(struct module *mod,
4155				  struct trace_enum_map **start, int len)
4156{
4157	struct trace_enum_map **map;
4158
4159	if (len <= 0)
4160		return;
4161
4162	map = start;
4163
4164	trace_event_enum_update(map, len);
4165
4166	trace_insert_enum_map_file(mod, start, len);
4167}
4168
4169static ssize_t
4170tracing_set_trace_read(struct file *filp, char __user *ubuf,
4171		       size_t cnt, loff_t *ppos)
4172{
4173	struct trace_array *tr = filp->private_data;
4174	char buf[MAX_TRACER_SIZE+2];
4175	int r;
4176
4177	mutex_lock(&trace_types_lock);
4178	r = sprintf(buf, "%s\n", tr->current_trace->name);
 
 
 
4179	mutex_unlock(&trace_types_lock);
4180
4181	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4182}
4183
4184int tracer_init(struct tracer *t, struct trace_array *tr)
4185{
4186	tracing_reset_online_cpus(&tr->trace_buffer);
4187	return t->init(tr);
4188}
4189
4190static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
4191{
4192	int cpu;
4193
4194	for_each_tracing_cpu(cpu)
4195		per_cpu_ptr(buf->data, cpu)->entries = val;
4196}
4197
4198#ifdef CONFIG_TRACER_MAX_TRACE
4199/* resize @tr's buffer to the size of @size_tr's entries */
4200static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
4201					struct trace_buffer *size_buf, int cpu_id)
4202{
4203	int cpu, ret = 0;
4204
4205	if (cpu_id == RING_BUFFER_ALL_CPUS) {
4206		for_each_tracing_cpu(cpu) {
4207			ret = ring_buffer_resize(trace_buf->buffer,
4208				 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
4209			if (ret < 0)
4210				break;
4211			per_cpu_ptr(trace_buf->data, cpu)->entries =
4212				per_cpu_ptr(size_buf->data, cpu)->entries;
4213		}
4214	} else {
4215		ret = ring_buffer_resize(trace_buf->buffer,
4216				 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
4217		if (ret == 0)
4218			per_cpu_ptr(trace_buf->data, cpu_id)->entries =
4219				per_cpu_ptr(size_buf->data, cpu_id)->entries;
4220	}
4221
4222	return ret;
4223}
4224#endif /* CONFIG_TRACER_MAX_TRACE */
4225
4226static int __tracing_resize_ring_buffer(struct trace_array *tr,
4227					unsigned long size, int cpu)
4228{
4229	int ret;
4230
4231	/*
4232	 * If kernel or user changes the size of the ring buffer
4233	 * we use the size that was given, and we can forget about
4234	 * expanding it later.
4235	 */
4236	ring_buffer_expanded = true;
4237
4238	/* May be called before buffers are initialized */
4239	if (!tr->trace_buffer.buffer)
4240		return 0;
4241
4242	ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
4243	if (ret < 0)
4244		return ret;
4245
4246#ifdef CONFIG_TRACER_MAX_TRACE
4247	if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
4248	    !tr->current_trace->use_max_tr)
4249		goto out;
4250
4251	ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
4252	if (ret < 0) {
4253		int r = resize_buffer_duplicate_size(&tr->trace_buffer,
4254						     &tr->trace_buffer, cpu);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4255		if (r < 0) {
4256			/*
4257			 * AARGH! We are left with different
4258			 * size max buffer!!!!
4259			 * The max buffer is our "snapshot" buffer.
4260			 * When a tracer needs a snapshot (one of the
4261			 * latency tracers), it swaps the max buffer
4262			 * with the saved snap shot. We succeeded to
4263			 * update the size of the main buffer, but failed to
4264			 * update the size of the max buffer. But when we tried
4265			 * to reset the main buffer to the original size, we
4266			 * failed there too. This is very unlikely to
4267			 * happen, but if it does, warn and kill all
4268			 * tracing.
4269			 */
4270			WARN_ON(1);
4271			tracing_disabled = 1;
4272		}
4273		return ret;
4274	}
4275
4276	if (cpu == RING_BUFFER_ALL_CPUS)
4277		set_buffer_entries(&tr->max_buffer, size);
4278	else
4279		per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
4280
4281 out:
4282#endif /* CONFIG_TRACER_MAX_TRACE */
4283
4284	if (cpu == RING_BUFFER_ALL_CPUS)
4285		set_buffer_entries(&tr->trace_buffer, size);
4286	else
4287		per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
4288
4289	return ret;
4290}
4291
4292static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
4293					  unsigned long size, int cpu_id)
4294{
4295	int ret = size;
4296
4297	mutex_lock(&trace_types_lock);
4298
4299	if (cpu_id != RING_BUFFER_ALL_CPUS) {
4300		/* make sure, this cpu is enabled in the mask */
4301		if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
4302			ret = -EINVAL;
4303			goto out;
4304		}
4305	}
4306
4307	ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
4308	if (ret < 0)
4309		ret = -ENOMEM;
4310
4311out:
4312	mutex_unlock(&trace_types_lock);
4313
4314	return ret;
4315}
4316
4317
4318/**
4319 * tracing_update_buffers - used by tracing facility to expand ring buffers
4320 *
4321 * To save on memory when the tracing is never used on a system with it
4322 * configured in. The ring buffers are set to a minimum size. But once
4323 * a user starts to use the tracing facility, then they need to grow
4324 * to their default size.
4325 *
4326 * This function is to be called when a tracer is about to be used.
4327 */
4328int tracing_update_buffers(void)
4329{
4330	int ret = 0;
4331
4332	mutex_lock(&trace_types_lock);
4333	if (!ring_buffer_expanded)
4334		ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
4335						RING_BUFFER_ALL_CPUS);
4336	mutex_unlock(&trace_types_lock);
4337
4338	return ret;
4339}
4340
4341struct trace_option_dentry;
4342
4343static void
4344create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
4345
4346/*
4347 * Used to clear out the tracer before deletion of an instance.
4348 * Must have trace_types_lock held.
4349 */
4350static void tracing_set_nop(struct trace_array *tr)
4351{
4352	if (tr->current_trace == &nop_trace)
4353		return;
4354	
4355	tr->current_trace->enabled--;
4356
4357	if (tr->current_trace->reset)
4358		tr->current_trace->reset(tr);
4359
4360	tr->current_trace = &nop_trace;
4361}
4362
4363static void add_tracer_options(struct trace_array *tr, struct tracer *t)
4364{
4365	/* Only enable if the directory has been created already. */
4366	if (!tr->dir)
4367		return;
4368
4369	create_trace_option_files(tr, t);
4370}
4371
4372static int tracing_set_tracer(struct trace_array *tr, const char *buf)
4373{
 
 
4374	struct tracer *t;
4375#ifdef CONFIG_TRACER_MAX_TRACE
4376	bool had_max_tr;
4377#endif
4378	int ret = 0;
4379
4380	mutex_lock(&trace_types_lock);
4381
4382	if (!ring_buffer_expanded) {
4383		ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
4384						RING_BUFFER_ALL_CPUS);
4385		if (ret < 0)
4386			goto out;
4387		ret = 0;
4388	}
4389
4390	for (t = trace_types; t; t = t->next) {
4391		if (strcmp(t->name, buf) == 0)
4392			break;
4393	}
4394	if (!t) {
4395		ret = -EINVAL;
4396		goto out;
4397	}
4398	if (t == tr->current_trace)
4399		goto out;
4400
4401	/* Some tracers are only allowed for the top level buffer */
4402	if (!trace_ok_for_array(t, tr)) {
4403		ret = -EINVAL;
4404		goto out;
4405	}
4406
4407	/* If trace pipe files are being read, we can't change the tracer */
4408	if (tr->current_trace->ref) {
4409		ret = -EBUSY;
4410		goto out;
4411	}
4412
4413	trace_branch_disable();
4414
4415	tr->current_trace->enabled--;
4416
4417	if (tr->current_trace->reset)
4418		tr->current_trace->reset(tr);
4419
4420	/* Current trace needs to be nop_trace before synchronize_sched */
4421	tr->current_trace = &nop_trace;
4422
4423#ifdef CONFIG_TRACER_MAX_TRACE
4424	had_max_tr = tr->allocated_snapshot;
4425
4426	if (had_max_tr && !t->use_max_tr) {
4427		/*
4428		 * We need to make sure that the update_max_tr sees that
4429		 * current_trace changed to nop_trace to keep it from
4430		 * swapping the buffers after we resize it.
4431		 * The update_max_tr is called from interrupts disabled
4432		 * so a synchronized_sched() is sufficient.
4433		 */
4434		synchronize_sched();
4435		free_snapshot(tr);
4436	}
4437#endif
4438
4439#ifdef CONFIG_TRACER_MAX_TRACE
4440	if (t->use_max_tr && !had_max_tr) {
4441		ret = alloc_snapshot(tr);
4442		if (ret < 0)
4443			goto out;
 
 
 
 
 
 
 
 
 
 
4444	}
4445#endif
4446
4447	if (t->init) {
4448		ret = tracer_init(t, tr);
4449		if (ret)
4450			goto out;
4451	}
4452
4453	tr->current_trace = t;
4454	tr->current_trace->enabled++;
4455	trace_branch_enable(tr);
4456 out:
4457	mutex_unlock(&trace_types_lock);
4458
4459	return ret;
4460}
4461
4462static ssize_t
4463tracing_set_trace_write(struct file *filp, const char __user *ubuf,
4464			size_t cnt, loff_t *ppos)
4465{
4466	struct trace_array *tr = filp->private_data;
4467	char buf[MAX_TRACER_SIZE+1];
4468	int i;
4469	size_t ret;
4470	int err;
4471
4472	ret = cnt;
4473
4474	if (cnt > MAX_TRACER_SIZE)
4475		cnt = MAX_TRACER_SIZE;
4476
4477	if (copy_from_user(&buf, ubuf, cnt))
4478		return -EFAULT;
4479
4480	buf[cnt] = 0;
4481
4482	/* strip ending whitespace. */
4483	for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
4484		buf[i] = 0;
4485
4486	err = tracing_set_tracer(tr, buf);
4487	if (err)
4488		return err;
4489
4490	*ppos += ret;
4491
4492	return ret;
4493}
4494
4495static ssize_t
4496tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
4497		   size_t cnt, loff_t *ppos)
4498{
 
4499	char buf[64];
4500	int r;
4501
4502	r = snprintf(buf, sizeof(buf), "%ld\n",
4503		     *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
4504	if (r > sizeof(buf))
4505		r = sizeof(buf);
4506	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4507}
4508
4509static ssize_t
4510tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
4511		    size_t cnt, loff_t *ppos)
4512{
 
4513	unsigned long val;
4514	int ret;
4515
4516	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4517	if (ret)
4518		return ret;
4519
4520	*ptr = val * 1000;
4521
4522	return cnt;
4523}
4524
4525static ssize_t
4526tracing_thresh_read(struct file *filp, char __user *ubuf,
4527		    size_t cnt, loff_t *ppos)
4528{
4529	return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
4530}
4531
4532static ssize_t
4533tracing_thresh_write(struct file *filp, const char __user *ubuf,
4534		     size_t cnt, loff_t *ppos)
4535{
4536	struct trace_array *tr = filp->private_data;
4537	int ret;
4538
4539	mutex_lock(&trace_types_lock);
4540	ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
4541	if (ret < 0)
4542		goto out;
4543
4544	if (tr->current_trace->update_thresh) {
4545		ret = tr->current_trace->update_thresh(tr);
4546		if (ret < 0)
4547			goto out;
4548	}
4549
4550	ret = cnt;
4551out:
4552	mutex_unlock(&trace_types_lock);
4553
4554	return ret;
4555}
4556
4557#ifdef CONFIG_TRACER_MAX_TRACE
4558
4559static ssize_t
4560tracing_max_lat_read(struct file *filp, char __user *ubuf,
4561		     size_t cnt, loff_t *ppos)
4562{
4563	return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
4564}
4565
4566static ssize_t
4567tracing_max_lat_write(struct file *filp, const char __user *ubuf,
4568		      size_t cnt, loff_t *ppos)
4569{
4570	return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
4571}
4572
4573#endif
4574
4575static int tracing_open_pipe(struct inode *inode, struct file *filp)
4576{
4577	struct trace_array *tr = inode->i_private;
4578	struct trace_iterator *iter;
4579	int ret = 0;
4580
4581	if (tracing_disabled)
4582		return -ENODEV;
4583
4584	if (trace_array_get(tr) < 0)
4585		return -ENODEV;
4586
4587	mutex_lock(&trace_types_lock);
4588
4589	/* create a buffer to store the information to pass to userspace */
4590	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4591	if (!iter) {
4592		ret = -ENOMEM;
4593		__trace_array_put(tr);
4594		goto out;
4595	}
4596
4597	trace_seq_init(&iter->seq);
4598	iter->trace = tr->current_trace;
 
 
 
 
 
 
 
 
 
4599
4600	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
4601		ret = -ENOMEM;
4602		goto fail;
4603	}
4604
4605	/* trace pipe does not show start of buffer */
4606	cpumask_setall(iter->started);
4607
4608	if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4609		iter->iter_flags |= TRACE_FILE_LAT_FMT;
4610
4611	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
4612	if (trace_clocks[tr->clock_id].in_ns)
4613		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4614
4615	iter->tr = tr;
4616	iter->trace_buffer = &tr->trace_buffer;
4617	iter->cpu_file = tracing_get_cpu(inode);
4618	mutex_init(&iter->mutex);
4619	filp->private_data = iter;
4620
4621	if (iter->trace->pipe_open)
4622		iter->trace->pipe_open(iter);
4623
4624	nonseekable_open(inode, filp);
4625
4626	tr->current_trace->ref++;
4627out:
4628	mutex_unlock(&trace_types_lock);
4629	return ret;
4630
4631fail:
4632	kfree(iter->trace);
4633	kfree(iter);
4634	__trace_array_put(tr);
4635	mutex_unlock(&trace_types_lock);
4636	return ret;
4637}
4638
4639static int tracing_release_pipe(struct inode *inode, struct file *file)
4640{
4641	struct trace_iterator *iter = file->private_data;
4642	struct trace_array *tr = inode->i_private;
4643
4644	mutex_lock(&trace_types_lock);
4645
4646	tr->current_trace->ref--;
4647
4648	if (iter->trace->pipe_close)
4649		iter->trace->pipe_close(iter);
4650
4651	mutex_unlock(&trace_types_lock);
4652
4653	free_cpumask_var(iter->started);
4654	mutex_destroy(&iter->mutex);
 
4655	kfree(iter);
4656
4657	trace_array_put(tr);
4658
4659	return 0;
4660}
4661
4662static unsigned int
4663trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
4664{
4665	struct trace_array *tr = iter->tr;
4666
4667	/* Iterators are static, they should be filled or empty */
4668	if (trace_buffer_iter(iter, iter->cpu_file))
4669		return POLLIN | POLLRDNORM;
4670
4671	if (tr->trace_flags & TRACE_ITER_BLOCK)
4672		/*
4673		 * Always select as readable when in blocking mode
4674		 */
4675		return POLLIN | POLLRDNORM;
4676	else
4677		return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
4678					     filp, poll_table);
 
 
 
 
 
 
4679}
4680
4681static unsigned int
4682tracing_poll_pipe(struct file *filp, poll_table *poll_table)
4683{
4684	struct trace_iterator *iter = filp->private_data;
 
 
4685
4686	return trace_poll(iter, filp, poll_table);
 
 
 
4687}
4688
4689/* Must be called with iter->mutex held. */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4690static int tracing_wait_pipe(struct file *filp)
4691{
4692	struct trace_iterator *iter = filp->private_data;
4693	int ret;
4694
4695	while (trace_empty(iter)) {
4696
4697		if ((filp->f_flags & O_NONBLOCK)) {
4698			return -EAGAIN;
4699		}
4700
 
 
 
 
 
 
 
 
 
4701		/*
4702		 * We block until we read something and tracing is disabled.
4703		 * We still block if tracing is disabled, but we have never
4704		 * read anything. This allows a user to cat this file, and
4705		 * then enable tracing. But after we have read something,
4706		 * we give an EOF when tracing is again disabled.
4707		 *
4708		 * iter->pos will be 0 if we haven't read anything.
4709		 */
4710		if (!tracing_is_on() && iter->pos)
4711			break;
4712
4713		mutex_unlock(&iter->mutex);
4714
4715		ret = wait_on_pipe(iter, false);
4716
4717		mutex_lock(&iter->mutex);
4718
4719		if (ret)
4720			return ret;
4721	}
4722
4723	return 1;
4724}
4725
4726/*
4727 * Consumer reader.
4728 */
4729static ssize_t
4730tracing_read_pipe(struct file *filp, char __user *ubuf,
4731		  size_t cnt, loff_t *ppos)
4732{
4733	struct trace_iterator *iter = filp->private_data;
 
4734	ssize_t sret;
4735
4736	/* return any leftover data */
4737	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4738	if (sret != -EBUSY)
4739		return sret;
4740
4741	trace_seq_init(&iter->seq);
4742
 
 
 
 
 
 
 
 
4743	/*
4744	 * Avoid more than one consumer on a single file descriptor
4745	 * This is just a matter of traces coherency, the ring buffer itself
4746	 * is protected.
4747	 */
4748	mutex_lock(&iter->mutex);
4749	if (iter->trace->read) {
4750		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
4751		if (sret)
4752			goto out;
4753	}
4754
4755waitagain:
4756	sret = tracing_wait_pipe(filp);
4757	if (sret <= 0)
4758		goto out;
4759
4760	/* stop when tracing is finished */
4761	if (trace_empty(iter)) {
4762		sret = 0;
4763		goto out;
4764	}
4765
4766	if (cnt >= PAGE_SIZE)
4767		cnt = PAGE_SIZE - 1;
4768
4769	/* reset all but tr, trace, and overruns */
4770	memset(&iter->seq, 0,
4771	       sizeof(struct trace_iterator) -
4772	       offsetof(struct trace_iterator, seq));
4773	cpumask_clear(iter->started);
4774	iter->pos = -1;
4775
4776	trace_event_read_lock();
4777	trace_access_lock(iter->cpu_file);
4778	while (trace_find_next_entry_inc(iter) != NULL) {
4779		enum print_line_t ret;
4780		int save_len = iter->seq.seq.len;
4781
4782		ret = print_trace_line(iter);
4783		if (ret == TRACE_TYPE_PARTIAL_LINE) {
4784			/* don't print partial lines */
4785			iter->seq.seq.len = save_len;
4786			break;
4787		}
4788		if (ret != TRACE_TYPE_NO_CONSUME)
4789			trace_consume(iter);
4790
4791		if (trace_seq_used(&iter->seq) >= cnt)
4792			break;
4793
4794		/*
4795		 * Setting the full flag means we reached the trace_seq buffer
4796		 * size and we should leave by partial output condition above.
4797		 * One of the trace_seq_* functions is not used properly.
4798		 */
4799		WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
4800			  iter->ent->type);
4801	}
4802	trace_access_unlock(iter->cpu_file);
4803	trace_event_read_unlock();
4804
4805	/* Now copy what we have to the user */
4806	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4807	if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
4808		trace_seq_init(&iter->seq);
4809
4810	/*
4811	 * If there was nothing to send to user, in spite of consuming trace
4812	 * entries, go back to wait for more entries.
4813	 */
4814	if (sret == -EBUSY)
4815		goto waitagain;
4816
4817out:
4818	mutex_unlock(&iter->mutex);
4819
4820	return sret;
4821}
4822
 
 
 
 
 
 
4823static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
4824				     unsigned int idx)
4825{
4826	__free_page(spd->pages[idx]);
4827}
4828
4829static const struct pipe_buf_operations tracing_pipe_buf_ops = {
4830	.can_merge		= 0,
 
 
4831	.confirm		= generic_pipe_buf_confirm,
4832	.release		= generic_pipe_buf_release,
4833	.steal			= generic_pipe_buf_steal,
4834	.get			= generic_pipe_buf_get,
4835};
4836
4837static size_t
4838tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
4839{
4840	size_t count;
4841	int save_len;
4842	int ret;
4843
4844	/* Seq buffer is page-sized, exactly what we need. */
4845	for (;;) {
4846		save_len = iter->seq.seq.len;
4847		ret = print_trace_line(iter);
4848
4849		if (trace_seq_has_overflowed(&iter->seq)) {
4850			iter->seq.seq.len = save_len;
 
4851			break;
4852		}
4853
4854		/*
4855		 * This should not be hit, because it should only
4856		 * be set if the iter->seq overflowed. But check it
4857		 * anyway to be safe.
4858		 */
4859		if (ret == TRACE_TYPE_PARTIAL_LINE) {
4860			iter->seq.seq.len = save_len;
4861			break;
4862		}
4863
4864		count = trace_seq_used(&iter->seq) - save_len;
4865		if (rem < count) {
4866			rem = 0;
4867			iter->seq.seq.len = save_len;
4868			break;
4869		}
4870
4871		if (ret != TRACE_TYPE_NO_CONSUME)
4872			trace_consume(iter);
4873		rem -= count;
4874		if (!trace_find_next_entry_inc(iter))	{
4875			rem = 0;
4876			iter->ent = NULL;
4877			break;
4878		}
4879	}
4880
4881	return rem;
4882}
4883
4884static ssize_t tracing_splice_read_pipe(struct file *filp,
4885					loff_t *ppos,
4886					struct pipe_inode_info *pipe,
4887					size_t len,
4888					unsigned int flags)
4889{
4890	struct page *pages_def[PIPE_DEF_BUFFERS];
4891	struct partial_page partial_def[PIPE_DEF_BUFFERS];
4892	struct trace_iterator *iter = filp->private_data;
4893	struct splice_pipe_desc spd = {
4894		.pages		= pages_def,
4895		.partial	= partial_def,
4896		.nr_pages	= 0, /* This gets updated below. */
4897		.nr_pages_max	= PIPE_DEF_BUFFERS,
4898		.flags		= flags,
4899		.ops		= &tracing_pipe_buf_ops,
4900		.spd_release	= tracing_spd_release_pipe,
4901	};
 
4902	ssize_t ret;
4903	size_t rem;
4904	unsigned int i;
4905
4906	if (splice_grow_spd(pipe, &spd))
4907		return -ENOMEM;
4908
 
 
 
 
 
 
 
 
4909	mutex_lock(&iter->mutex);
4910
4911	if (iter->trace->splice_read) {
4912		ret = iter->trace->splice_read(iter, filp,
4913					       ppos, pipe, len, flags);
4914		if (ret)
4915			goto out_err;
4916	}
4917
4918	ret = tracing_wait_pipe(filp);
4919	if (ret <= 0)
4920		goto out_err;
4921
4922	if (!iter->ent && !trace_find_next_entry_inc(iter)) {
4923		ret = -EFAULT;
4924		goto out_err;
4925	}
4926
4927	trace_event_read_lock();
4928	trace_access_lock(iter->cpu_file);
4929
4930	/* Fill as many pages as possible. */
4931	for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
4932		spd.pages[i] = alloc_page(GFP_KERNEL);
4933		if (!spd.pages[i])
4934			break;
4935
4936		rem = tracing_fill_pipe_page(rem, iter);
4937
4938		/* Copy the data into the page, so we can start over. */
4939		ret = trace_seq_to_buffer(&iter->seq,
4940					  page_address(spd.pages[i]),
4941					  trace_seq_used(&iter->seq));
4942		if (ret < 0) {
4943			__free_page(spd.pages[i]);
4944			break;
4945		}
4946		spd.partial[i].offset = 0;
4947		spd.partial[i].len = trace_seq_used(&iter->seq);
4948
4949		trace_seq_init(&iter->seq);
4950	}
4951
4952	trace_access_unlock(iter->cpu_file);
4953	trace_event_read_unlock();
4954	mutex_unlock(&iter->mutex);
4955
4956	spd.nr_pages = i;
4957
4958	if (i)
4959		ret = splice_to_pipe(pipe, &spd);
4960	else
4961		ret = 0;
4962out:
4963	splice_shrink_spd(&spd);
4964	return ret;
4965
4966out_err:
4967	mutex_unlock(&iter->mutex);
4968	goto out;
4969}
4970
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4971static ssize_t
4972tracing_entries_read(struct file *filp, char __user *ubuf,
4973		     size_t cnt, loff_t *ppos)
4974{
4975	struct inode *inode = file_inode(filp);
4976	struct trace_array *tr = inode->i_private;
4977	int cpu = tracing_get_cpu(inode);
4978	char buf[64];
4979	int r = 0;
4980	ssize_t ret;
4981
4982	mutex_lock(&trace_types_lock);
4983
4984	if (cpu == RING_BUFFER_ALL_CPUS) {
4985		int cpu, buf_size_same;
4986		unsigned long size;
4987
4988		size = 0;
4989		buf_size_same = 1;
4990		/* check if all cpu sizes are same */
4991		for_each_tracing_cpu(cpu) {
4992			/* fill in the size from first enabled cpu */
4993			if (size == 0)
4994				size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
4995			if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
4996				buf_size_same = 0;
4997				break;
4998			}
4999		}
5000
5001		if (buf_size_same) {
5002			if (!ring_buffer_expanded)
5003				r = sprintf(buf, "%lu (expanded: %lu)\n",
5004					    size >> 10,
5005					    trace_buf_size >> 10);
5006			else
5007				r = sprintf(buf, "%lu\n", size >> 10);
5008		} else
5009			r = sprintf(buf, "X\n");
5010	} else
5011		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
5012
5013	mutex_unlock(&trace_types_lock);
5014
5015	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5016	return ret;
5017}
5018
5019static ssize_t
5020tracing_entries_write(struct file *filp, const char __user *ubuf,
5021		      size_t cnt, loff_t *ppos)
5022{
5023	struct inode *inode = file_inode(filp);
5024	struct trace_array *tr = inode->i_private;
5025	unsigned long val;
5026	int ret;
5027
5028	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5029	if (ret)
5030		return ret;
5031
5032	/* must have at least 1 entry */
5033	if (!val)
5034		return -EINVAL;
5035
5036	/* value is in KB */
5037	val <<= 10;
5038	ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
 
5039	if (ret < 0)
5040		return ret;
5041
5042	*ppos += cnt;
5043
5044	return cnt;
5045}
5046
 
 
 
 
 
 
 
 
 
 
5047static ssize_t
5048tracing_total_entries_read(struct file *filp, char __user *ubuf,
5049				size_t cnt, loff_t *ppos)
5050{
5051	struct trace_array *tr = filp->private_data;
5052	char buf[64];
5053	int r, cpu;
5054	unsigned long size = 0, expanded_size = 0;
5055
5056	mutex_lock(&trace_types_lock);
5057	for_each_tracing_cpu(cpu) {
5058		size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
5059		if (!ring_buffer_expanded)
5060			expanded_size += trace_buf_size >> 10;
5061	}
5062	if (ring_buffer_expanded)
5063		r = sprintf(buf, "%lu\n", size);
5064	else
5065		r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
5066	mutex_unlock(&trace_types_lock);
5067
5068	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5069}
5070
5071static ssize_t
5072tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
5073			  size_t cnt, loff_t *ppos)
5074{
5075	/*
5076	 * There is no need to read what the user has written, this function
5077	 * is just to make sure that there is no error when "echo" is used
5078	 */
5079
5080	*ppos += cnt;
5081
5082	return cnt;
5083}
5084
5085static int
5086tracing_free_buffer_release(struct inode *inode, struct file *filp)
5087{
5088	struct trace_array *tr = inode->i_private;
5089
5090	/* disable tracing ? */
5091	if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
5092		tracer_tracing_off(tr);
5093	/* resize the ring buffer to 0 */
5094	tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
5095
5096	trace_array_put(tr);
5097
5098	return 0;
5099}
5100
5101static ssize_t
5102tracing_mark_write(struct file *filp, const char __user *ubuf,
5103					size_t cnt, loff_t *fpos)
5104{
5105	unsigned long addr = (unsigned long)ubuf;
5106	struct trace_array *tr = filp->private_data;
5107	struct ring_buffer_event *event;
5108	struct ring_buffer *buffer;
5109	struct print_entry *entry;
5110	unsigned long irq_flags;
5111	struct page *pages[2];
5112	void *map_page[2];
5113	int nr_pages = 1;
5114	ssize_t written;
5115	int offset;
5116	int size;
5117	int len;
5118	int ret;
5119	int i;
5120
5121	if (tracing_disabled)
5122		return -EINVAL;
5123
5124	if (!(tr->trace_flags & TRACE_ITER_MARKERS))
5125		return -EINVAL;
5126
5127	if (cnt > TRACE_BUF_SIZE)
5128		cnt = TRACE_BUF_SIZE;
5129
5130	/*
5131	 * Userspace is injecting traces into the kernel trace buffer.
5132	 * We want to be as non intrusive as possible.
5133	 * To do so, we do not want to allocate any special buffers
5134	 * or take any locks, but instead write the userspace data
5135	 * straight into the ring buffer.
5136	 *
5137	 * First we need to pin the userspace buffer into memory,
5138	 * which, most likely it is, because it just referenced it.
5139	 * But there's no guarantee that it is. By using get_user_pages_fast()
5140	 * and kmap_atomic/kunmap_atomic() we can get access to the
5141	 * pages directly. We then write the data directly into the
5142	 * ring buffer.
5143	 */
5144	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
5145
5146	/* check if we cross pages */
5147	if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
5148		nr_pages = 2;
5149
5150	offset = addr & (PAGE_SIZE - 1);
5151	addr &= PAGE_MASK;
5152
5153	ret = get_user_pages_fast(addr, nr_pages, 0, pages);
5154	if (ret < nr_pages) {
5155		while (--ret >= 0)
5156			put_page(pages[ret]);
5157		written = -EFAULT;
5158		goto out;
5159	}
5160
5161	for (i = 0; i < nr_pages; i++)
5162		map_page[i] = kmap_atomic(pages[i]);
5163
5164	local_save_flags(irq_flags);
5165	size = sizeof(*entry) + cnt + 2; /* possible \n added */
5166	buffer = tr->trace_buffer.buffer;
5167	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
5168					  irq_flags, preempt_count());
5169	if (!event) {
5170		/* Ring buffer disabled, return as if not open for write */
5171		written = -EBADF;
5172		goto out_unlock;
5173	}
5174
5175	entry = ring_buffer_event_data(event);
5176	entry->ip = _THIS_IP_;
5177
5178	if (nr_pages == 2) {
5179		len = PAGE_SIZE - offset;
5180		memcpy(&entry->buf, map_page[0] + offset, len);
5181		memcpy(&entry->buf[len], map_page[1], cnt - len);
5182	} else
5183		memcpy(&entry->buf, map_page[0] + offset, cnt);
5184
5185	if (entry->buf[cnt - 1] != '\n') {
5186		entry->buf[cnt] = '\n';
5187		entry->buf[cnt + 1] = '\0';
5188	} else
5189		entry->buf[cnt] = '\0';
5190
5191	__buffer_unlock_commit(buffer, event);
5192
5193	written = cnt;
5194
5195	*fpos += written;
5196
5197 out_unlock:
5198	for (i = nr_pages - 1; i >= 0; i--) {
5199		kunmap_atomic(map_page[i]);
5200		put_page(pages[i]);
5201	}
5202 out:
5203	return written;
5204}
5205
5206static int tracing_clock_show(struct seq_file *m, void *v)
5207{
5208	struct trace_array *tr = m->private;
5209	int i;
5210
5211	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
5212		seq_printf(m,
5213			"%s%s%s%s", i ? " " : "",
5214			i == tr->clock_id ? "[" : "", trace_clocks[i].name,
5215			i == tr->clock_id ? "]" : "");
5216	seq_putc(m, '\n');
5217
5218	return 0;
5219}
5220
5221static int tracing_set_clock(struct trace_array *tr, const char *clockstr)
5222{
5223	int i;
5224
5225	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
5226		if (strcmp(trace_clocks[i].name, clockstr) == 0)
5227			break;
5228	}
5229	if (i == ARRAY_SIZE(trace_clocks))
5230		return -EINVAL;
5231
5232	mutex_lock(&trace_types_lock);
5233
5234	tr->clock_id = i;
5235
5236	ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
5237
5238	/*
5239	 * New clock may not be consistent with the previous clock.
5240	 * Reset the buffer so that it doesn't have incomparable timestamps.
5241	 */
5242	tracing_reset_online_cpus(&tr->trace_buffer);
5243
5244#ifdef CONFIG_TRACER_MAX_TRACE
5245	if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
5246		ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
5247	tracing_reset_online_cpus(&tr->max_buffer);
5248#endif
5249
5250	mutex_unlock(&trace_types_lock);
5251
5252	return 0;
5253}
5254
5255static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
5256				   size_t cnt, loff_t *fpos)
5257{
5258	struct seq_file *m = filp->private_data;
5259	struct trace_array *tr = m->private;
5260	char buf[64];
5261	const char *clockstr;
5262	int ret;
5263
5264	if (cnt >= sizeof(buf))
5265		return -EINVAL;
5266
5267	if (copy_from_user(&buf, ubuf, cnt))
5268		return -EFAULT;
5269
5270	buf[cnt] = 0;
5271
5272	clockstr = strstrip(buf);
5273
5274	ret = tracing_set_clock(tr, clockstr);
5275	if (ret)
5276		return ret;
5277
5278	*fpos += cnt;
5279
5280	return cnt;
5281}
5282
5283static int tracing_clock_open(struct inode *inode, struct file *file)
5284{
5285	struct trace_array *tr = inode->i_private;
5286	int ret;
5287
5288	if (tracing_disabled)
5289		return -ENODEV;
5290
5291	if (trace_array_get(tr))
5292		return -ENODEV;
5293
5294	ret = single_open(file, tracing_clock_show, inode->i_private);
5295	if (ret < 0)
5296		trace_array_put(tr);
5297
5298	return ret;
5299}
5300
5301struct ftrace_buffer_info {
5302	struct trace_iterator	iter;
5303	void			*spare;
5304	unsigned int		read;
5305};
5306
5307#ifdef CONFIG_TRACER_SNAPSHOT
5308static int tracing_snapshot_open(struct inode *inode, struct file *file)
5309{
5310	struct trace_array *tr = inode->i_private;
5311	struct trace_iterator *iter;
5312	struct seq_file *m;
5313	int ret = 0;
5314
5315	if (trace_array_get(tr) < 0)
5316		return -ENODEV;
5317
5318	if (file->f_mode & FMODE_READ) {
5319		iter = __tracing_open(inode, file, true);
5320		if (IS_ERR(iter))
5321			ret = PTR_ERR(iter);
5322	} else {
5323		/* Writes still need the seq_file to hold the private data */
5324		ret = -ENOMEM;
5325		m = kzalloc(sizeof(*m), GFP_KERNEL);
5326		if (!m)
5327			goto out;
5328		iter = kzalloc(sizeof(*iter), GFP_KERNEL);
5329		if (!iter) {
5330			kfree(m);
5331			goto out;
5332		}
5333		ret = 0;
5334
5335		iter->tr = tr;
5336		iter->trace_buffer = &tr->max_buffer;
5337		iter->cpu_file = tracing_get_cpu(inode);
5338		m->private = iter;
5339		file->private_data = m;
5340	}
5341out:
5342	if (ret < 0)
5343		trace_array_put(tr);
5344
5345	return ret;
5346}
5347
5348static ssize_t
5349tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
5350		       loff_t *ppos)
5351{
5352	struct seq_file *m = filp->private_data;
5353	struct trace_iterator *iter = m->private;
5354	struct trace_array *tr = iter->tr;
5355	unsigned long val;
5356	int ret;
5357
5358	ret = tracing_update_buffers();
5359	if (ret < 0)
5360		return ret;
5361
5362	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5363	if (ret)
5364		return ret;
5365
5366	mutex_lock(&trace_types_lock);
5367
5368	if (tr->current_trace->use_max_tr) {
5369		ret = -EBUSY;
5370		goto out;
5371	}
5372
5373	switch (val) {
5374	case 0:
5375		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
5376			ret = -EINVAL;
5377			break;
5378		}
5379		if (tr->allocated_snapshot)
5380			free_snapshot(tr);
5381		break;
5382	case 1:
5383/* Only allow per-cpu swap if the ring buffer supports it */
5384#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
5385		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
5386			ret = -EINVAL;
5387			break;
5388		}
5389#endif
5390		if (!tr->allocated_snapshot) {
5391			ret = alloc_snapshot(tr);
5392			if (ret < 0)
5393				break;
5394		}
5395		local_irq_disable();
5396		/* Now, we're going to swap */
5397		if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
5398			update_max_tr(tr, current, smp_processor_id());
5399		else
5400			update_max_tr_single(tr, current, iter->cpu_file);
5401		local_irq_enable();
5402		break;
5403	default:
5404		if (tr->allocated_snapshot) {
5405			if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
5406				tracing_reset_online_cpus(&tr->max_buffer);
5407			else
5408				tracing_reset(&tr->max_buffer, iter->cpu_file);
5409		}
5410		break;
5411	}
5412
5413	if (ret >= 0) {
5414		*ppos += cnt;
5415		ret = cnt;
5416	}
5417out:
5418	mutex_unlock(&trace_types_lock);
5419	return ret;
5420}
5421
5422static int tracing_snapshot_release(struct inode *inode, struct file *file)
5423{
5424	struct seq_file *m = file->private_data;
5425	int ret;
5426
5427	ret = tracing_release(inode, file);
5428
5429	if (file->f_mode & FMODE_READ)
5430		return ret;
5431
5432	/* If write only, the seq_file is just a stub */
5433	if (m)
5434		kfree(m->private);
5435	kfree(m);
5436
5437	return 0;
5438}
5439
5440static int tracing_buffers_open(struct inode *inode, struct file *filp);
5441static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
5442				    size_t count, loff_t *ppos);
5443static int tracing_buffers_release(struct inode *inode, struct file *file);
5444static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5445		   struct pipe_inode_info *pipe, size_t len, unsigned int flags);
5446
5447static int snapshot_raw_open(struct inode *inode, struct file *filp)
5448{
5449	struct ftrace_buffer_info *info;
5450	int ret;
5451
5452	ret = tracing_buffers_open(inode, filp);
5453	if (ret < 0)
5454		return ret;
5455
5456	info = filp->private_data;
5457
5458	if (info->iter.trace->use_max_tr) {
5459		tracing_buffers_release(inode, filp);
5460		return -EBUSY;
5461	}
5462
5463	info->iter.snapshot = true;
5464	info->iter.trace_buffer = &info->iter.tr->max_buffer;
5465
5466	return ret;
5467}
5468
5469#endif /* CONFIG_TRACER_SNAPSHOT */
5470
5471
5472static const struct file_operations tracing_thresh_fops = {
5473	.open		= tracing_open_generic,
5474	.read		= tracing_thresh_read,
5475	.write		= tracing_thresh_write,
5476	.llseek		= generic_file_llseek,
5477};
5478
5479#ifdef CONFIG_TRACER_MAX_TRACE
5480static const struct file_operations tracing_max_lat_fops = {
5481	.open		= tracing_open_generic,
5482	.read		= tracing_max_lat_read,
5483	.write		= tracing_max_lat_write,
5484	.llseek		= generic_file_llseek,
5485};
5486#endif
5487
5488static const struct file_operations set_tracer_fops = {
5489	.open		= tracing_open_generic,
5490	.read		= tracing_set_trace_read,
5491	.write		= tracing_set_trace_write,
5492	.llseek		= generic_file_llseek,
5493};
5494
5495static const struct file_operations tracing_pipe_fops = {
5496	.open		= tracing_open_pipe,
5497	.poll		= tracing_poll_pipe,
5498	.read		= tracing_read_pipe,
5499	.splice_read	= tracing_splice_read_pipe,
5500	.release	= tracing_release_pipe,
5501	.llseek		= no_llseek,
5502};
5503
5504static const struct file_operations tracing_entries_fops = {
5505	.open		= tracing_open_generic_tr,
5506	.read		= tracing_entries_read,
5507	.write		= tracing_entries_write,
 
5508	.llseek		= generic_file_llseek,
5509	.release	= tracing_release_generic_tr,
5510};
5511
5512static const struct file_operations tracing_total_entries_fops = {
5513	.open		= tracing_open_generic_tr,
5514	.read		= tracing_total_entries_read,
5515	.llseek		= generic_file_llseek,
5516	.release	= tracing_release_generic_tr,
5517};
5518
5519static const struct file_operations tracing_free_buffer_fops = {
5520	.open		= tracing_open_generic_tr,
5521	.write		= tracing_free_buffer_write,
5522	.release	= tracing_free_buffer_release,
5523};
5524
5525static const struct file_operations tracing_mark_fops = {
5526	.open		= tracing_open_generic_tr,
5527	.write		= tracing_mark_write,
5528	.llseek		= generic_file_llseek,
5529	.release	= tracing_release_generic_tr,
5530};
5531
5532static const struct file_operations trace_clock_fops = {
5533	.open		= tracing_clock_open,
5534	.read		= seq_read,
5535	.llseek		= seq_lseek,
5536	.release	= tracing_single_release_tr,
5537	.write		= tracing_clock_write,
5538};
5539
5540#ifdef CONFIG_TRACER_SNAPSHOT
5541static const struct file_operations snapshot_fops = {
5542	.open		= tracing_snapshot_open,
5543	.read		= seq_read,
5544	.write		= tracing_snapshot_write,
5545	.llseek		= tracing_lseek,
5546	.release	= tracing_snapshot_release,
5547};
5548
5549static const struct file_operations snapshot_raw_fops = {
5550	.open		= snapshot_raw_open,
5551	.read		= tracing_buffers_read,
5552	.release	= tracing_buffers_release,
5553	.splice_read	= tracing_buffers_splice_read,
5554	.llseek		= no_llseek,
5555};
5556
5557#endif /* CONFIG_TRACER_SNAPSHOT */
5558
5559static int tracing_buffers_open(struct inode *inode, struct file *filp)
5560{
5561	struct trace_array *tr = inode->i_private;
5562	struct ftrace_buffer_info *info;
5563	int ret;
5564
5565	if (tracing_disabled)
5566		return -ENODEV;
5567
5568	if (trace_array_get(tr) < 0)
5569		return -ENODEV;
5570
5571	info = kzalloc(sizeof(*info), GFP_KERNEL);
5572	if (!info) {
5573		trace_array_put(tr);
5574		return -ENOMEM;
5575	}
5576
5577	mutex_lock(&trace_types_lock);
5578
5579	info->iter.tr		= tr;
5580	info->iter.cpu_file	= tracing_get_cpu(inode);
5581	info->iter.trace	= tr->current_trace;
5582	info->iter.trace_buffer = &tr->trace_buffer;
5583	info->spare		= NULL;
5584	/* Force reading ring buffer for first read */
5585	info->read		= (unsigned int)-1;
5586
5587	filp->private_data = info;
5588
5589	tr->current_trace->ref++;
5590
5591	mutex_unlock(&trace_types_lock);
5592
5593	ret = nonseekable_open(inode, filp);
5594	if (ret < 0)
5595		trace_array_put(tr);
5596
5597	return ret;
5598}
5599
5600static unsigned int
5601tracing_buffers_poll(struct file *filp, poll_table *poll_table)
5602{
5603	struct ftrace_buffer_info *info = filp->private_data;
5604	struct trace_iterator *iter = &info->iter;
5605
5606	return trace_poll(iter, filp, poll_table);
5607}
5608
5609static ssize_t
5610tracing_buffers_read(struct file *filp, char __user *ubuf,
5611		     size_t count, loff_t *ppos)
5612{
5613	struct ftrace_buffer_info *info = filp->private_data;
5614	struct trace_iterator *iter = &info->iter;
5615	ssize_t ret;
5616	ssize_t size;
5617
5618	if (!count)
5619		return 0;
5620
5621#ifdef CONFIG_TRACER_MAX_TRACE
5622	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
5623		return -EBUSY;
5624#endif
5625
5626	if (!info->spare)
5627		info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
5628							  iter->cpu_file);
5629	if (!info->spare)
5630		return -ENOMEM;
5631
5632	/* Do we have previous read data to read? */
5633	if (info->read < PAGE_SIZE)
5634		goto read;
5635
5636 again:
5637	trace_access_lock(iter->cpu_file);
5638	ret = ring_buffer_read_page(iter->trace_buffer->buffer,
5639				    &info->spare,
5640				    count,
5641				    iter->cpu_file, 0);
5642	trace_access_unlock(iter->cpu_file);
5643
5644	if (ret < 0) {
5645		if (trace_empty(iter)) {
5646			if ((filp->f_flags & O_NONBLOCK))
5647				return -EAGAIN;
5648
5649			ret = wait_on_pipe(iter, false);
5650			if (ret)
5651				return ret;
5652
5653			goto again;
5654		}
5655		return 0;
5656	}
5657
5658	info->read = 0;
5659 read:
 
5660	size = PAGE_SIZE - info->read;
5661	if (size > count)
5662		size = count;
5663
5664	ret = copy_to_user(ubuf, info->spare + info->read, size);
5665	if (ret == size)
5666		return -EFAULT;
5667
5668	size -= ret;
5669
5670	*ppos += size;
5671	info->read += size;
5672
5673	return size;
5674}
5675
5676static int tracing_buffers_release(struct inode *inode, struct file *file)
5677{
5678	struct ftrace_buffer_info *info = file->private_data;
5679	struct trace_iterator *iter = &info->iter;
5680
5681	mutex_lock(&trace_types_lock);
5682
5683	iter->tr->current_trace->ref--;
5684
5685	__trace_array_put(iter->tr);
5686
5687	if (info->spare)
5688		ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);
5689	kfree(info);
5690
5691	mutex_unlock(&trace_types_lock);
5692
5693	return 0;
5694}
5695
5696struct buffer_ref {
5697	struct ring_buffer	*buffer;
5698	void			*page;
5699	int			ref;
5700};
5701
5702static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
5703				    struct pipe_buffer *buf)
5704{
5705	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5706
5707	if (--ref->ref)
5708		return;
5709
5710	ring_buffer_free_read_page(ref->buffer, ref->page);
5711	kfree(ref);
5712	buf->private = 0;
5713}
5714
 
 
 
 
 
 
5715static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
5716				struct pipe_buffer *buf)
5717{
5718	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5719
5720	ref->ref++;
5721}
5722
5723/* Pipe buffer operations for a buffer. */
5724static const struct pipe_buf_operations buffer_pipe_buf_ops = {
5725	.can_merge		= 0,
 
 
5726	.confirm		= generic_pipe_buf_confirm,
5727	.release		= buffer_pipe_buf_release,
5728	.steal			= generic_pipe_buf_steal,
5729	.get			= buffer_pipe_buf_get,
5730};
5731
5732/*
5733 * Callback from splice_to_pipe(), if we need to release some pages
5734 * at the end of the spd in case we error'ed out in filling the pipe.
5735 */
5736static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
5737{
5738	struct buffer_ref *ref =
5739		(struct buffer_ref *)spd->partial[i].private;
5740
5741	if (--ref->ref)
5742		return;
5743
5744	ring_buffer_free_read_page(ref->buffer, ref->page);
5745	kfree(ref);
5746	spd->partial[i].private = 0;
5747}
5748
5749static ssize_t
5750tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5751			    struct pipe_inode_info *pipe, size_t len,
5752			    unsigned int flags)
5753{
5754	struct ftrace_buffer_info *info = file->private_data;
5755	struct trace_iterator *iter = &info->iter;
5756	struct partial_page partial_def[PIPE_DEF_BUFFERS];
5757	struct page *pages_def[PIPE_DEF_BUFFERS];
5758	struct splice_pipe_desc spd = {
5759		.pages		= pages_def,
5760		.partial	= partial_def,
5761		.nr_pages_max	= PIPE_DEF_BUFFERS,
5762		.flags		= flags,
5763		.ops		= &buffer_pipe_buf_ops,
5764		.spd_release	= buffer_spd_release,
5765	};
5766	struct buffer_ref *ref;
5767	int entries, size, i;
5768	ssize_t ret = 0;
5769
5770#ifdef CONFIG_TRACER_MAX_TRACE
5771	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
5772		return -EBUSY;
5773#endif
5774
5775	if (splice_grow_spd(pipe, &spd))
5776		return -ENOMEM;
5777
5778	if (*ppos & (PAGE_SIZE - 1))
5779		return -EINVAL;
 
 
 
5780
5781	if (len & (PAGE_SIZE - 1)) {
5782		if (len < PAGE_SIZE)
5783			return -EINVAL;
 
 
 
5784		len &= PAGE_MASK;
5785	}
5786
5787 again:
5788	trace_access_lock(iter->cpu_file);
5789	entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5790
5791	for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
5792		struct page *page;
5793		int r;
5794
5795		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
5796		if (!ref) {
5797			ret = -ENOMEM;
5798			break;
5799		}
5800
5801		ref->ref = 1;
5802		ref->buffer = iter->trace_buffer->buffer;
5803		ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
5804		if (!ref->page) {
5805			ret = -ENOMEM;
5806			kfree(ref);
5807			break;
5808		}
5809
5810		r = ring_buffer_read_page(ref->buffer, &ref->page,
5811					  len, iter->cpu_file, 1);
5812		if (r < 0) {
5813			ring_buffer_free_read_page(ref->buffer, ref->page);
5814			kfree(ref);
5815			break;
5816		}
5817
5818		/*
5819		 * zero out any left over data, this is going to
5820		 * user land.
5821		 */
5822		size = ring_buffer_page_len(ref->page);
5823		if (size < PAGE_SIZE)
5824			memset(ref->page + size, 0, PAGE_SIZE - size);
5825
5826		page = virt_to_page(ref->page);
5827
5828		spd.pages[i] = page;
5829		spd.partial[i].len = PAGE_SIZE;
5830		spd.partial[i].offset = 0;
5831		spd.partial[i].private = (unsigned long)ref;
5832		spd.nr_pages++;
5833		*ppos += PAGE_SIZE;
5834
5835		entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5836	}
5837
5838	trace_access_unlock(iter->cpu_file);
5839	spd.nr_pages = i;
5840
5841	/* did we read anything? */
5842	if (!spd.nr_pages) {
5843		if (ret)
5844			return ret;
5845
5846		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
5847			return -EAGAIN;
5848
5849		ret = wait_on_pipe(iter, true);
5850		if (ret)
5851			return ret;
5852
5853		goto again;
5854	}
5855
5856	ret = splice_to_pipe(pipe, &spd);
5857	splice_shrink_spd(&spd);
5858
5859	return ret;
5860}
5861
5862static const struct file_operations tracing_buffers_fops = {
5863	.open		= tracing_buffers_open,
5864	.read		= tracing_buffers_read,
5865	.poll		= tracing_buffers_poll,
5866	.release	= tracing_buffers_release,
5867	.splice_read	= tracing_buffers_splice_read,
5868	.llseek		= no_llseek,
5869};
5870
5871static ssize_t
5872tracing_stats_read(struct file *filp, char __user *ubuf,
5873		   size_t count, loff_t *ppos)
5874{
5875	struct inode *inode = file_inode(filp);
5876	struct trace_array *tr = inode->i_private;
5877	struct trace_buffer *trace_buf = &tr->trace_buffer;
5878	int cpu = tracing_get_cpu(inode);
5879	struct trace_seq *s;
5880	unsigned long cnt;
5881	unsigned long long t;
5882	unsigned long usec_rem;
5883
5884	s = kmalloc(sizeof(*s), GFP_KERNEL);
5885	if (!s)
5886		return -ENOMEM;
5887
5888	trace_seq_init(s);
5889
5890	cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
5891	trace_seq_printf(s, "entries: %ld\n", cnt);
5892
5893	cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
5894	trace_seq_printf(s, "overrun: %ld\n", cnt);
5895
5896	cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
5897	trace_seq_printf(s, "commit overrun: %ld\n", cnt);
5898
5899	cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
5900	trace_seq_printf(s, "bytes: %ld\n", cnt);
5901
5902	if (trace_clocks[tr->clock_id].in_ns) {
5903		/* local or global for trace_clock */
5904		t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5905		usec_rem = do_div(t, USEC_PER_SEC);
5906		trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
5907								t, usec_rem);
5908
5909		t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
5910		usec_rem = do_div(t, USEC_PER_SEC);
5911		trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
5912	} else {
5913		/* counter or tsc mode for trace_clock */
5914		trace_seq_printf(s, "oldest event ts: %llu\n",
5915				ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5916
5917		trace_seq_printf(s, "now ts: %llu\n",
5918				ring_buffer_time_stamp(trace_buf->buffer, cpu));
5919	}
5920
5921	cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
5922	trace_seq_printf(s, "dropped events: %ld\n", cnt);
5923
5924	cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
5925	trace_seq_printf(s, "read events: %ld\n", cnt);
5926
5927	count = simple_read_from_buffer(ubuf, count, ppos,
5928					s->buffer, trace_seq_used(s));
5929
5930	kfree(s);
5931
5932	return count;
5933}
5934
5935static const struct file_operations tracing_stats_fops = {
5936	.open		= tracing_open_generic_tr,
5937	.read		= tracing_stats_read,
5938	.llseek		= generic_file_llseek,
5939	.release	= tracing_release_generic_tr,
5940};
5941
5942#ifdef CONFIG_DYNAMIC_FTRACE
5943
5944int __weak ftrace_arch_read_dyn_info(char *buf, int size)
5945{
5946	return 0;
5947}
5948
5949static ssize_t
5950tracing_read_dyn_info(struct file *filp, char __user *ubuf,
5951		  size_t cnt, loff_t *ppos)
5952{
5953	static char ftrace_dyn_info_buffer[1024];
5954	static DEFINE_MUTEX(dyn_info_mutex);
5955	unsigned long *p = filp->private_data;
5956	char *buf = ftrace_dyn_info_buffer;
5957	int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
5958	int r;
5959
5960	mutex_lock(&dyn_info_mutex);
5961	r = sprintf(buf, "%ld ", *p);
5962
5963	r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
5964	buf[r++] = '\n';
5965
5966	r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5967
5968	mutex_unlock(&dyn_info_mutex);
5969
5970	return r;
5971}
5972
5973static const struct file_operations tracing_dyn_info_fops = {
5974	.open		= tracing_open_generic,
5975	.read		= tracing_read_dyn_info,
5976	.llseek		= generic_file_llseek,
5977};
5978#endif /* CONFIG_DYNAMIC_FTRACE */
5979
5980#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5981static void
5982ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5983{
5984	tracing_snapshot();
5985}
5986
5987static void
5988ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5989{
5990	unsigned long *count = (long *)data;
5991
5992	if (!*count)
5993		return;
5994
5995	if (*count != -1)
5996		(*count)--;
5997
5998	tracing_snapshot();
5999}
6000
6001static int
6002ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
6003		      struct ftrace_probe_ops *ops, void *data)
6004{
6005	long count = (long)data;
6006
6007	seq_printf(m, "%ps:", (void *)ip);
6008
6009	seq_puts(m, "snapshot");
6010
6011	if (count == -1)
6012		seq_puts(m, ":unlimited\n");
6013	else
6014		seq_printf(m, ":count=%ld\n", count);
6015
6016	return 0;
6017}
6018
6019static struct ftrace_probe_ops snapshot_probe_ops = {
6020	.func			= ftrace_snapshot,
6021	.print			= ftrace_snapshot_print,
6022};
6023
6024static struct ftrace_probe_ops snapshot_count_probe_ops = {
6025	.func			= ftrace_count_snapshot,
6026	.print			= ftrace_snapshot_print,
6027};
6028
6029static int
6030ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
6031			       char *glob, char *cmd, char *param, int enable)
6032{
6033	struct ftrace_probe_ops *ops;
6034	void *count = (void *)-1;
6035	char *number;
6036	int ret;
6037
6038	/* hash funcs only work with set_ftrace_filter */
6039	if (!enable)
6040		return -EINVAL;
6041
6042	ops = param ? &snapshot_count_probe_ops :  &snapshot_probe_ops;
6043
6044	if (glob[0] == '!') {
6045		unregister_ftrace_function_probe_func(glob+1, ops);
6046		return 0;
 
6047	}
6048
6049	if (!param)
6050		goto out_reg;
6051
6052	number = strsep(&param, ":");
6053
6054	if (!strlen(number))
6055		goto out_reg;
6056
6057	/*
6058	 * We use the callback data field (which is a pointer)
6059	 * as our counter.
6060	 */
6061	ret = kstrtoul(number, 0, (unsigned long *)&count);
6062	if (ret)
6063		return ret;
6064
6065 out_reg:
6066	ret = register_ftrace_function_probe(glob, ops, count);
6067
6068	if (ret >= 0)
6069		alloc_snapshot(&global_trace);
6070
6071	return ret < 0 ? ret : 0;
6072}
6073
6074static struct ftrace_func_command ftrace_snapshot_cmd = {
6075	.name			= "snapshot",
6076	.func			= ftrace_trace_snapshot_callback,
6077};
6078
6079static __init int register_snapshot_cmd(void)
6080{
6081	return register_ftrace_command(&ftrace_snapshot_cmd);
6082}
6083#else
6084static inline __init int register_snapshot_cmd(void) { return 0; }
6085#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
6086
6087static struct dentry *tracing_get_dentry(struct trace_array *tr)
6088{
6089	if (WARN_ON(!tr->dir))
6090		return ERR_PTR(-ENODEV);
6091
6092	/* Top directory uses NULL as the parent */
6093	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
6094		return NULL;
6095
6096	/* All sub buffers have a descriptor */
6097	return tr->dir;
6098}
6099
6100static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
6101{
 
6102	struct dentry *d_tracer;
6103
6104	if (tr->percpu_dir)
6105		return tr->percpu_dir;
6106
6107	d_tracer = tracing_get_dentry(tr);
6108	if (IS_ERR(d_tracer))
6109		return NULL;
6110
6111	tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
 
6112
6113	WARN_ONCE(!tr->percpu_dir,
6114		  "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
6115
6116	return tr->percpu_dir;
6117}
6118
6119static struct dentry *
6120trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
6121		      void *data, long cpu, const struct file_operations *fops)
6122{
6123	struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
6124
6125	if (ret) /* See tracing_get_cpu() */
6126		d_inode(ret)->i_cdev = (void *)(cpu + 1);
6127	return ret;
6128}
6129
6130static void
6131tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
6132{
6133	struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
6134	struct dentry *d_cpu;
6135	char cpu_dir[30]; /* 30 characters should be more than enough */
6136
6137	if (!d_percpu)
6138		return;
6139
6140	snprintf(cpu_dir, 30, "cpu%ld", cpu);
6141	d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
6142	if (!d_cpu) {
6143		pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
6144		return;
6145	}
6146
6147	/* per cpu trace_pipe */
6148	trace_create_cpu_file("trace_pipe", 0444, d_cpu,
6149				tr, cpu, &tracing_pipe_fops);
6150
6151	/* per cpu trace */
6152	trace_create_cpu_file("trace", 0644, d_cpu,
6153				tr, cpu, &tracing_fops);
6154
6155	trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
6156				tr, cpu, &tracing_buffers_fops);
6157
6158	trace_create_cpu_file("stats", 0444, d_cpu,
6159				tr, cpu, &tracing_stats_fops);
6160
6161	trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
6162				tr, cpu, &tracing_entries_fops);
6163
6164#ifdef CONFIG_TRACER_SNAPSHOT
6165	trace_create_cpu_file("snapshot", 0644, d_cpu,
6166				tr, cpu, &snapshot_fops);
6167
6168	trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
6169				tr, cpu, &snapshot_raw_fops);
6170#endif
6171}
6172
6173#ifdef CONFIG_FTRACE_SELFTEST
6174/* Let selftest have access to static functions in this file */
6175#include "trace_selftest.c"
6176#endif
6177
 
 
 
 
 
 
6178static ssize_t
6179trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
6180			loff_t *ppos)
6181{
6182	struct trace_option_dentry *topt = filp->private_data;
6183	char *buf;
6184
6185	if (topt->flags->val & topt->opt->bit)
6186		buf = "1\n";
6187	else
6188		buf = "0\n";
6189
6190	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
6191}
6192
6193static ssize_t
6194trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
6195			 loff_t *ppos)
6196{
6197	struct trace_option_dentry *topt = filp->private_data;
6198	unsigned long val;
6199	int ret;
6200
6201	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6202	if (ret)
6203		return ret;
6204
6205	if (val != 0 && val != 1)
6206		return -EINVAL;
6207
6208	if (!!(topt->flags->val & topt->opt->bit) != val) {
6209		mutex_lock(&trace_types_lock);
6210		ret = __set_tracer_option(topt->tr, topt->flags,
6211					  topt->opt, !val);
6212		mutex_unlock(&trace_types_lock);
6213		if (ret)
6214			return ret;
6215	}
6216
6217	*ppos += cnt;
6218
6219	return cnt;
6220}
6221
6222
6223static const struct file_operations trace_options_fops = {
6224	.open = tracing_open_generic,
6225	.read = trace_options_read,
6226	.write = trace_options_write,
6227	.llseek	= generic_file_llseek,
6228};
6229
6230/*
6231 * In order to pass in both the trace_array descriptor as well as the index
6232 * to the flag that the trace option file represents, the trace_array
6233 * has a character array of trace_flags_index[], which holds the index
6234 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
6235 * The address of this character array is passed to the flag option file
6236 * read/write callbacks.
6237 *
6238 * In order to extract both the index and the trace_array descriptor,
6239 * get_tr_index() uses the following algorithm.
6240 *
6241 *   idx = *ptr;
6242 *
6243 * As the pointer itself contains the address of the index (remember
6244 * index[1] == 1).
6245 *
6246 * Then to get the trace_array descriptor, by subtracting that index
6247 * from the ptr, we get to the start of the index itself.
6248 *
6249 *   ptr - idx == &index[0]
6250 *
6251 * Then a simple container_of() from that pointer gets us to the
6252 * trace_array descriptor.
6253 */
6254static void get_tr_index(void *data, struct trace_array **ptr,
6255			 unsigned int *pindex)
6256{
6257	*pindex = *(unsigned char *)data;
6258
6259	*ptr = container_of(data - *pindex, struct trace_array,
6260			    trace_flags_index);
6261}
6262
6263static ssize_t
6264trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
6265			loff_t *ppos)
6266{
6267	void *tr_index = filp->private_data;
6268	struct trace_array *tr;
6269	unsigned int index;
6270	char *buf;
6271
6272	get_tr_index(tr_index, &tr, &index);
6273
6274	if (tr->trace_flags & (1 << index))
6275		buf = "1\n";
6276	else
6277		buf = "0\n";
6278
6279	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
6280}
6281
6282static ssize_t
6283trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
6284			 loff_t *ppos)
6285{
6286	void *tr_index = filp->private_data;
6287	struct trace_array *tr;
6288	unsigned int index;
6289	unsigned long val;
6290	int ret;
6291
6292	get_tr_index(tr_index, &tr, &index);
6293
6294	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6295	if (ret)
6296		return ret;
6297
6298	if (val != 0 && val != 1)
6299		return -EINVAL;
6300
6301	mutex_lock(&trace_types_lock);
6302	ret = set_tracer_flag(tr, 1 << index, val);
6303	mutex_unlock(&trace_types_lock);
6304
6305	if (ret < 0)
6306		return ret;
6307
6308	*ppos += cnt;
6309
6310	return cnt;
6311}
6312
6313static const struct file_operations trace_options_core_fops = {
6314	.open = tracing_open_generic,
6315	.read = trace_options_core_read,
6316	.write = trace_options_core_write,
6317	.llseek = generic_file_llseek,
6318};
6319
6320struct dentry *trace_create_file(const char *name,
6321				 umode_t mode,
6322				 struct dentry *parent,
6323				 void *data,
6324				 const struct file_operations *fops)
6325{
6326	struct dentry *ret;
6327
6328	ret = tracefs_create_file(name, mode, parent, data, fops);
6329	if (!ret)
6330		pr_warn("Could not create tracefs '%s' entry\n", name);
6331
6332	return ret;
6333}
6334
6335
6336static struct dentry *trace_options_init_dentry(struct trace_array *tr)
6337{
6338	struct dentry *d_tracer;
 
6339
6340	if (tr->options)
6341		return tr->options;
6342
6343	d_tracer = tracing_get_dentry(tr);
6344	if (IS_ERR(d_tracer))
6345		return NULL;
6346
6347	tr->options = tracefs_create_dir("options", d_tracer);
6348	if (!tr->options) {
6349		pr_warn("Could not create tracefs directory 'options'\n");
6350		return NULL;
6351	}
6352
6353	return tr->options;
6354}
6355
6356static void
6357create_trace_option_file(struct trace_array *tr,
6358			 struct trace_option_dentry *topt,
6359			 struct tracer_flags *flags,
6360			 struct tracer_opt *opt)
6361{
6362	struct dentry *t_options;
6363
6364	t_options = trace_options_init_dentry(tr);
6365	if (!t_options)
6366		return;
6367
6368	topt->flags = flags;
6369	topt->opt = opt;
6370	topt->tr = tr;
6371
6372	topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
6373				    &trace_options_fops);
6374
6375}
6376
6377static void
6378create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
6379{
6380	struct trace_option_dentry *topts;
6381	struct trace_options *tr_topts;
6382	struct tracer_flags *flags;
6383	struct tracer_opt *opts;
6384	int cnt;
6385	int i;
6386
6387	if (!tracer)
6388		return;
6389
6390	flags = tracer->flags;
6391
6392	if (!flags || !flags->opts)
6393		return;
6394
6395	/*
6396	 * If this is an instance, only create flags for tracers
6397	 * the instance may have.
6398	 */
6399	if (!trace_ok_for_array(tracer, tr))
6400		return;
6401
6402	for (i = 0; i < tr->nr_topts; i++) {
6403		/* Make sure there's no duplicate flags. */
6404		if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
6405			return;
6406	}
6407
6408	opts = flags->opts;
6409
6410	for (cnt = 0; opts[cnt].name; cnt++)
6411		;
6412
6413	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
6414	if (!topts)
6415		return;
6416
6417	tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
6418			    GFP_KERNEL);
6419	if (!tr_topts) {
6420		kfree(topts);
6421		return;
6422	}
6423
6424	tr->topts = tr_topts;
6425	tr->topts[tr->nr_topts].tracer = tracer;
6426	tr->topts[tr->nr_topts].topts = topts;
6427	tr->nr_topts++;
6428
6429	for (cnt = 0; opts[cnt].name; cnt++) {
6430		create_trace_option_file(tr, &topts[cnt], flags,
6431					 &opts[cnt]);
6432		WARN_ONCE(topts[cnt].entry == NULL,
6433			  "Failed to create trace option: %s",
6434			  opts[cnt].name);
 
 
 
 
 
6435	}
 
 
6436}
6437
6438static struct dentry *
6439create_trace_option_core_file(struct trace_array *tr,
6440			      const char *option, long index)
6441{
6442	struct dentry *t_options;
6443
6444	t_options = trace_options_init_dentry(tr);
6445	if (!t_options)
6446		return NULL;
6447
6448	return trace_create_file(option, 0644, t_options,
6449				 (void *)&tr->trace_flags_index[index],
6450				 &trace_options_core_fops);
6451}
6452
6453static void create_trace_options_dir(struct trace_array *tr)
6454{
6455	struct dentry *t_options;
6456	bool top_level = tr == &global_trace;
6457	int i;
6458
6459	t_options = trace_options_init_dentry(tr);
6460	if (!t_options)
6461		return;
6462
6463	for (i = 0; trace_options[i]; i++) {
6464		if (top_level ||
6465		    !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
6466			create_trace_option_core_file(tr, trace_options[i], i);
6467	}
6468}
6469
6470static ssize_t
6471rb_simple_read(struct file *filp, char __user *ubuf,
6472	       size_t cnt, loff_t *ppos)
6473{
6474	struct trace_array *tr = filp->private_data;
 
6475	char buf[64];
6476	int r;
6477
6478	r = tracer_tracing_is_on(tr);
 
 
 
 
6479	r = sprintf(buf, "%d\n", r);
6480
6481	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6482}
6483
6484static ssize_t
6485rb_simple_write(struct file *filp, const char __user *ubuf,
6486		size_t cnt, loff_t *ppos)
6487{
6488	struct trace_array *tr = filp->private_data;
6489	struct ring_buffer *buffer = tr->trace_buffer.buffer;
6490	unsigned long val;
6491	int ret;
6492
6493	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6494	if (ret)
6495		return ret;
6496
6497	if (buffer) {
6498		mutex_lock(&trace_types_lock);
6499		if (val) {
6500			tracer_tracing_on(tr);
6501			if (tr->current_trace->start)
6502				tr->current_trace->start(tr);
6503		} else {
6504			tracer_tracing_off(tr);
6505			if (tr->current_trace->stop)
6506				tr->current_trace->stop(tr);
6507		}
6508		mutex_unlock(&trace_types_lock);
6509	}
6510
6511	(*ppos)++;
6512
6513	return cnt;
6514}
6515
6516static const struct file_operations rb_simple_fops = {
6517	.open		= tracing_open_generic_tr,
6518	.read		= rb_simple_read,
6519	.write		= rb_simple_write,
6520	.release	= tracing_release_generic_tr,
6521	.llseek		= default_llseek,
6522};
6523
6524struct dentry *trace_instance_dir;
6525
6526static void
6527init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
6528
6529static int
6530allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
6531{
6532	enum ring_buffer_flags rb_flags;
6533
6534	rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
6535
6536	buf->tr = tr;
6537
6538	buf->buffer = ring_buffer_alloc(size, rb_flags);
6539	if (!buf->buffer)
6540		return -ENOMEM;
6541
6542	buf->data = alloc_percpu(struct trace_array_cpu);
6543	if (!buf->data) {
6544		ring_buffer_free(buf->buffer);
6545		return -ENOMEM;
6546	}
6547
6548	/* Allocate the first page for all buffers */
6549	set_buffer_entries(&tr->trace_buffer,
6550			   ring_buffer_size(tr->trace_buffer.buffer, 0));
6551
6552	return 0;
6553}
6554
6555static int allocate_trace_buffers(struct trace_array *tr, int size)
6556{
6557	int ret;
6558
6559	ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
6560	if (ret)
6561		return ret;
6562
6563#ifdef CONFIG_TRACER_MAX_TRACE
6564	ret = allocate_trace_buffer(tr, &tr->max_buffer,
6565				    allocate_snapshot ? size : 1);
6566	if (WARN_ON(ret)) {
6567		ring_buffer_free(tr->trace_buffer.buffer);
6568		free_percpu(tr->trace_buffer.data);
6569		return -ENOMEM;
6570	}
6571	tr->allocated_snapshot = allocate_snapshot;
6572
6573	/*
6574	 * Only the top level trace array gets its snapshot allocated
6575	 * from the kernel command line.
6576	 */
6577	allocate_snapshot = false;
6578#endif
6579	return 0;
6580}
6581
6582static void free_trace_buffer(struct trace_buffer *buf)
6583{
6584	if (buf->buffer) {
6585		ring_buffer_free(buf->buffer);
6586		buf->buffer = NULL;
6587		free_percpu(buf->data);
6588		buf->data = NULL;
6589	}
6590}
6591
6592static void free_trace_buffers(struct trace_array *tr)
6593{
6594	if (!tr)
6595		return;
6596
6597	free_trace_buffer(&tr->trace_buffer);
6598
6599#ifdef CONFIG_TRACER_MAX_TRACE
6600	free_trace_buffer(&tr->max_buffer);
6601#endif
6602}
6603
6604static void init_trace_flags_index(struct trace_array *tr)
6605{
6606	int i;
6607
6608	/* Used by the trace options files */
6609	for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
6610		tr->trace_flags_index[i] = i;
6611}
6612
6613static void __update_tracer_options(struct trace_array *tr)
6614{
6615	struct tracer *t;
6616
6617	for (t = trace_types; t; t = t->next)
6618		add_tracer_options(tr, t);
6619}
6620
6621static void update_tracer_options(struct trace_array *tr)
6622{
6623	mutex_lock(&trace_types_lock);
6624	__update_tracer_options(tr);
6625	mutex_unlock(&trace_types_lock);
6626}
6627
6628static int instance_mkdir(const char *name)
6629{
6630	struct trace_array *tr;
6631	int ret;
6632
6633	mutex_lock(&trace_types_lock);
6634
6635	ret = -EEXIST;
6636	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6637		if (tr->name && strcmp(tr->name, name) == 0)
6638			goto out_unlock;
6639	}
6640
6641	ret = -ENOMEM;
6642	tr = kzalloc(sizeof(*tr), GFP_KERNEL);
6643	if (!tr)
6644		goto out_unlock;
6645
6646	tr->name = kstrdup(name, GFP_KERNEL);
6647	if (!tr->name)
6648		goto out_free_tr;
6649
6650	if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
6651		goto out_free_tr;
6652
6653	tr->trace_flags = global_trace.trace_flags;
6654
6655	cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
6656
6657	raw_spin_lock_init(&tr->start_lock);
6658
6659	tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
6660
6661	tr->current_trace = &nop_trace;
6662
6663	INIT_LIST_HEAD(&tr->systems);
6664	INIT_LIST_HEAD(&tr->events);
6665
6666	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
6667		goto out_free_tr;
6668
6669	tr->dir = tracefs_create_dir(name, trace_instance_dir);
6670	if (!tr->dir)
6671		goto out_free_tr;
6672
6673	ret = event_trace_add_tracer(tr->dir, tr);
6674	if (ret) {
6675		tracefs_remove_recursive(tr->dir);
6676		goto out_free_tr;
6677	}
6678
6679	init_tracer_tracefs(tr, tr->dir);
6680	init_trace_flags_index(tr);
6681	__update_tracer_options(tr);
6682
6683	list_add(&tr->list, &ftrace_trace_arrays);
6684
6685	mutex_unlock(&trace_types_lock);
6686
6687	return 0;
6688
6689 out_free_tr:
6690	free_trace_buffers(tr);
6691	free_cpumask_var(tr->tracing_cpumask);
6692	kfree(tr->name);
6693	kfree(tr);
6694
6695 out_unlock:
6696	mutex_unlock(&trace_types_lock);
6697
6698	return ret;
6699
6700}
6701
6702static int instance_rmdir(const char *name)
6703{
6704	struct trace_array *tr;
6705	int found = 0;
6706	int ret;
6707	int i;
6708
6709	mutex_lock(&trace_types_lock);
6710
6711	ret = -ENODEV;
6712	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6713		if (tr->name && strcmp(tr->name, name) == 0) {
6714			found = 1;
6715			break;
6716		}
6717	}
6718	if (!found)
6719		goto out_unlock;
6720
6721	ret = -EBUSY;
6722	if (tr->ref || (tr->current_trace && tr->current_trace->ref))
6723		goto out_unlock;
6724
6725	list_del(&tr->list);
6726
6727	tracing_set_nop(tr);
6728	event_trace_del_tracer(tr);
6729	ftrace_destroy_function_files(tr);
6730	tracefs_remove_recursive(tr->dir);
6731	free_trace_buffers(tr);
6732
6733	for (i = 0; i < tr->nr_topts; i++) {
6734		kfree(tr->topts[i].topts);
6735	}
6736	kfree(tr->topts);
6737
6738	kfree(tr->name);
6739	kfree(tr);
6740
6741	ret = 0;
6742
6743 out_unlock:
6744	mutex_unlock(&trace_types_lock);
6745
6746	return ret;
6747}
6748
6749static __init void create_trace_instances(struct dentry *d_tracer)
6750{
6751	trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
6752							 instance_mkdir,
6753							 instance_rmdir);
6754	if (WARN_ON(!trace_instance_dir))
6755		return;
6756}
6757
6758static void
6759init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6760{
6761	int cpu;
6762
6763	trace_create_file("available_tracers", 0444, d_tracer,
6764			tr, &show_traces_fops);
6765
6766	trace_create_file("current_tracer", 0644, d_tracer,
6767			tr, &set_tracer_fops);
6768
6769	trace_create_file("tracing_cpumask", 0644, d_tracer,
6770			  tr, &tracing_cpumask_fops);
 
 
6771
6772	trace_create_file("trace_options", 0644, d_tracer,
6773			  tr, &tracing_iter_fops);
6774
6775	trace_create_file("trace", 0644, d_tracer,
6776			  tr, &tracing_fops);
6777
6778	trace_create_file("trace_pipe", 0444, d_tracer,
6779			  tr, &tracing_pipe_fops);
6780
6781	trace_create_file("buffer_size_kb", 0644, d_tracer,
6782			  tr, &tracing_entries_fops);
6783
6784	trace_create_file("buffer_total_size_kb", 0444, d_tracer,
6785			  tr, &tracing_total_entries_fops);
6786
6787	trace_create_file("free_buffer", 0200, d_tracer,
6788			  tr, &tracing_free_buffer_fops);
6789
6790	trace_create_file("trace_marker", 0220, d_tracer,
6791			  tr, &tracing_mark_fops);
6792
6793	trace_create_file("trace_clock", 0644, d_tracer, tr,
6794			  &trace_clock_fops);
6795
6796	trace_create_file("tracing_on", 0644, d_tracer,
6797			  tr, &rb_simple_fops);
6798
6799	create_trace_options_dir(tr);
6800
6801#ifdef CONFIG_TRACER_MAX_TRACE
6802	trace_create_file("tracing_max_latency", 0644, d_tracer,
6803			&tr->max_latency, &tracing_max_lat_fops);
6804#endif
6805
6806	if (ftrace_create_function_files(tr, d_tracer))
6807		WARN(1, "Could not allocate function filter files");
6808
6809#ifdef CONFIG_TRACER_SNAPSHOT
6810	trace_create_file("snapshot", 0644, d_tracer,
6811			  tr, &snapshot_fops);
6812#endif
6813
6814	for_each_tracing_cpu(cpu)
6815		tracing_init_tracefs_percpu(tr, cpu);
6816
6817}
6818
6819static struct vfsmount *trace_automount(void *ingore)
6820{
6821	struct vfsmount *mnt;
6822	struct file_system_type *type;
6823
6824	/*
6825	 * To maintain backward compatibility for tools that mount
6826	 * debugfs to get to the tracing facility, tracefs is automatically
6827	 * mounted to the debugfs/tracing directory.
6828	 */
6829	type = get_fs_type("tracefs");
6830	if (!type)
6831		return NULL;
6832	mnt = vfs_kern_mount(type, 0, "tracefs", NULL);
6833	put_filesystem(type);
6834	if (IS_ERR(mnt))
6835		return NULL;
6836	mntget(mnt);
6837
6838	return mnt;
6839}
6840
6841/**
6842 * tracing_init_dentry - initialize top level trace array
6843 *
6844 * This is called when creating files or directories in the tracing
6845 * directory. It is called via fs_initcall() by any of the boot up code
6846 * and expects to return the dentry of the top level tracing directory.
6847 */
6848struct dentry *tracing_init_dentry(void)
6849{
6850	struct trace_array *tr = &global_trace;
6851
6852	/* The top level trace array uses  NULL as parent */
6853	if (tr->dir)
6854		return NULL;
6855
6856	if (WARN_ON(!tracefs_initialized()) ||
6857		(IS_ENABLED(CONFIG_DEBUG_FS) &&
6858		 WARN_ON(!debugfs_initialized())))
6859		return ERR_PTR(-ENODEV);
6860
6861	/*
6862	 * As there may still be users that expect the tracing
6863	 * files to exist in debugfs/tracing, we must automount
6864	 * the tracefs file system there, so older tools still
6865	 * work with the newer kerenl.
6866	 */
6867	tr->dir = debugfs_create_automount("tracing", NULL,
6868					   trace_automount, NULL);
6869	if (!tr->dir) {
6870		pr_warn_once("Could not create debugfs directory 'tracing'\n");
6871		return ERR_PTR(-ENOMEM);
6872	}
6873
6874	return NULL;
6875}
6876
6877extern struct trace_enum_map *__start_ftrace_enum_maps[];
6878extern struct trace_enum_map *__stop_ftrace_enum_maps[];
6879
6880static void __init trace_enum_init(void)
6881{
6882	int len;
6883
6884	len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
6885	trace_insert_enum_map(NULL, __start_ftrace_enum_maps, len);
6886}
6887
6888#ifdef CONFIG_MODULES
6889static void trace_module_add_enums(struct module *mod)
6890{
6891	if (!mod->num_trace_enums)
6892		return;
6893
6894	/*
6895	 * Modules with bad taint do not have events created, do
6896	 * not bother with enums either.
6897	 */
6898	if (trace_module_has_bad_taint(mod))
6899		return;
6900
6901	trace_insert_enum_map(mod, mod->trace_enums, mod->num_trace_enums);
6902}
6903
6904#ifdef CONFIG_TRACE_ENUM_MAP_FILE
6905static void trace_module_remove_enums(struct module *mod)
6906{
6907	union trace_enum_map_item *map;
6908	union trace_enum_map_item **last = &trace_enum_maps;
6909
6910	if (!mod->num_trace_enums)
6911		return;
6912
6913	mutex_lock(&trace_enum_mutex);
6914
6915	map = trace_enum_maps;
6916
6917	while (map) {
6918		if (map->head.mod == mod)
6919			break;
6920		map = trace_enum_jmp_to_tail(map);
6921		last = &map->tail.next;
6922		map = map->tail.next;
6923	}
6924	if (!map)
6925		goto out;
6926
6927	*last = trace_enum_jmp_to_tail(map)->tail.next;
6928	kfree(map);
6929 out:
6930	mutex_unlock(&trace_enum_mutex);
6931}
6932#else
6933static inline void trace_module_remove_enums(struct module *mod) { }
6934#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
6935
6936static int trace_module_notify(struct notifier_block *self,
6937			       unsigned long val, void *data)
6938{
6939	struct module *mod = data;
6940
6941	switch (val) {
6942	case MODULE_STATE_COMING:
6943		trace_module_add_enums(mod);
6944		break;
6945	case MODULE_STATE_GOING:
6946		trace_module_remove_enums(mod);
6947		break;
6948	}
6949
6950	return 0;
6951}
6952
6953static struct notifier_block trace_module_nb = {
6954	.notifier_call = trace_module_notify,
6955	.priority = 0,
6956};
6957#endif /* CONFIG_MODULES */
6958
6959static __init int tracer_init_tracefs(void)
6960{
6961	struct dentry *d_tracer;
6962
6963	trace_access_lock_init();
6964
6965	d_tracer = tracing_init_dentry();
6966	if (IS_ERR(d_tracer))
6967		return 0;
6968
6969	init_tracer_tracefs(&global_trace, d_tracer);
6970
6971	trace_create_file("tracing_thresh", 0644, d_tracer,
6972			&global_trace, &tracing_thresh_fops);
6973
6974	trace_create_file("README", 0444, d_tracer,
6975			NULL, &tracing_readme_fops);
6976
6977	trace_create_file("saved_cmdlines", 0444, d_tracer,
6978			NULL, &tracing_saved_cmdlines_fops);
6979
6980	trace_create_file("saved_cmdlines_size", 0644, d_tracer,
6981			  NULL, &tracing_saved_cmdlines_size_fops);
6982
6983	trace_enum_init();
6984
6985	trace_create_enum_file(d_tracer);
6986
6987#ifdef CONFIG_MODULES
6988	register_module_notifier(&trace_module_nb);
6989#endif
6990
6991#ifdef CONFIG_DYNAMIC_FTRACE
6992	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
6993			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
6994#endif
6995
6996	create_trace_instances(d_tracer);
6997
6998	update_tracer_options(&global_trace);
 
6999
7000	return 0;
7001}
7002
7003static int trace_panic_handler(struct notifier_block *this,
7004			       unsigned long event, void *unused)
7005{
7006	if (ftrace_dump_on_oops)
7007		ftrace_dump(ftrace_dump_on_oops);
7008	return NOTIFY_OK;
7009}
7010
7011static struct notifier_block trace_panic_notifier = {
7012	.notifier_call  = trace_panic_handler,
7013	.next           = NULL,
7014	.priority       = 150   /* priority: INT_MAX >= x >= 0 */
7015};
7016
7017static int trace_die_handler(struct notifier_block *self,
7018			     unsigned long val,
7019			     void *data)
7020{
7021	switch (val) {
7022	case DIE_OOPS:
7023		if (ftrace_dump_on_oops)
7024			ftrace_dump(ftrace_dump_on_oops);
7025		break;
7026	default:
7027		break;
7028	}
7029	return NOTIFY_OK;
7030}
7031
7032static struct notifier_block trace_die_notifier = {
7033	.notifier_call = trace_die_handler,
7034	.priority = 200
7035};
7036
7037/*
7038 * printk is set to max of 1024, we really don't need it that big.
7039 * Nothing should be printing 1000 characters anyway.
7040 */
7041#define TRACE_MAX_PRINT		1000
7042
7043/*
7044 * Define here KERN_TRACE so that we have one place to modify
7045 * it if we decide to change what log level the ftrace dump
7046 * should be at.
7047 */
7048#define KERN_TRACE		KERN_EMERG
7049
7050void
7051trace_printk_seq(struct trace_seq *s)
7052{
7053	/* Probably should print a warning here. */
7054	if (s->seq.len >= TRACE_MAX_PRINT)
7055		s->seq.len = TRACE_MAX_PRINT;
7056
7057	/*
7058	 * More paranoid code. Although the buffer size is set to
7059	 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
7060	 * an extra layer of protection.
7061	 */
7062	if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
7063		s->seq.len = s->seq.size - 1;
7064
7065	/* should be zero ended, but we are paranoid. */
7066	s->buffer[s->seq.len] = 0;
7067
7068	printk(KERN_TRACE "%s", s->buffer);
7069
7070	trace_seq_init(s);
7071}
7072
7073void trace_init_global_iter(struct trace_iterator *iter)
7074{
7075	iter->tr = &global_trace;
7076	iter->trace = iter->tr->current_trace;
7077	iter->cpu_file = RING_BUFFER_ALL_CPUS;
7078	iter->trace_buffer = &global_trace.trace_buffer;
7079
7080	if (iter->trace && iter->trace->open)
7081		iter->trace->open(iter);
7082
7083	/* Annotate start of buffers if we had overruns */
7084	if (ring_buffer_overruns(iter->trace_buffer->buffer))
7085		iter->iter_flags |= TRACE_FILE_ANNOTATE;
7086
7087	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
7088	if (trace_clocks[iter->tr->clock_id].in_ns)
7089		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
7090}
7091
7092void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
 
7093{
 
 
7094	/* use static because iter can be a bit big for the stack */
7095	static struct trace_iterator iter;
7096	static atomic_t dump_running;
7097	struct trace_array *tr = &global_trace;
7098	unsigned int old_userobj;
 
7099	unsigned long flags;
7100	int cnt = 0, cpu;
7101
7102	/* Only allow one dump user at a time. */
7103	if (atomic_inc_return(&dump_running) != 1) {
7104		atomic_dec(&dump_running);
7105		return;
7106	}
 
 
7107
7108	/*
7109	 * Always turn off tracing when we dump.
7110	 * We don't need to show trace output of what happens
7111	 * between multiple crashes.
7112	 *
7113	 * If the user does a sysrq-z, then they can re-enable
7114	 * tracing with echo 1 > tracing_on.
7115	 */
7116	tracing_off();
7117
7118	local_irq_save(flags);
 
 
 
 
 
 
 
7119
7120	/* Simulate the iterator */
7121	trace_init_global_iter(&iter);
7122
7123	for_each_tracing_cpu(cpu) {
7124		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
7125	}
7126
7127	old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
7128
7129	/* don't look at user memory in panic mode */
7130	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
 
 
 
 
7131
7132	switch (oops_dump_mode) {
7133	case DUMP_ALL:
7134		iter.cpu_file = RING_BUFFER_ALL_CPUS;
7135		break;
7136	case DUMP_ORIG:
7137		iter.cpu_file = raw_smp_processor_id();
7138		break;
7139	case DUMP_NONE:
7140		goto out_enable;
7141	default:
7142		printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
7143		iter.cpu_file = RING_BUFFER_ALL_CPUS;
7144	}
7145
7146	printk(KERN_TRACE "Dumping ftrace buffer:\n");
7147
7148	/* Did function tracer already get disabled? */
7149	if (ftrace_is_dead()) {
7150		printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
7151		printk("#          MAY BE MISSING FUNCTION EVENTS\n");
7152	}
7153
7154	/*
7155	 * We need to stop all tracing on all CPUS to read the
7156	 * the next buffer. This is a bit expensive, but is
7157	 * not done often. We fill all what we can read,
7158	 * and then release the locks again.
7159	 */
7160
7161	while (!trace_empty(&iter)) {
7162
7163		if (!cnt)
7164			printk(KERN_TRACE "---------------------------------\n");
7165
7166		cnt++;
7167
7168		/* reset all but tr, trace, and overruns */
7169		memset(&iter.seq, 0,
7170		       sizeof(struct trace_iterator) -
7171		       offsetof(struct trace_iterator, seq));
7172		iter.iter_flags |= TRACE_FILE_LAT_FMT;
7173		iter.pos = -1;
7174
7175		if (trace_find_next_entry_inc(&iter) != NULL) {
7176			int ret;
7177
7178			ret = print_trace_line(&iter);
7179			if (ret != TRACE_TYPE_NO_CONSUME)
7180				trace_consume(&iter);
7181		}
7182		touch_nmi_watchdog();
7183
7184		trace_printk_seq(&iter.seq);
7185	}
7186
7187	if (!cnt)
7188		printk(KERN_TRACE "   (ftrace buffer empty)\n");
7189	else
7190		printk(KERN_TRACE "---------------------------------\n");
7191
7192 out_enable:
7193	tr->trace_flags |= old_userobj;
 
 
7194
7195	for_each_tracing_cpu(cpu) {
7196		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
 
 
7197	}
7198 	atomic_dec(&dump_running);
 
 
7199	local_irq_restore(flags);
7200}
 
 
 
 
 
 
7201EXPORT_SYMBOL_GPL(ftrace_dump);
7202
7203__init static int tracer_alloc_buffers(void)
7204{
7205	int ring_buf_size;
 
 
7206	int ret = -ENOMEM;
7207
7208	/*
7209	 * Make sure we don't accidently add more trace options
7210	 * than we have bits for.
7211	 */
7212	BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
7213
7214	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
7215		goto out;
7216
7217	if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
7218		goto out_free_buffer_mask;
7219
7220	/* Only allocate trace_printk buffers if a trace_printk exists */
7221	if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
7222		/* Must be called before global_trace.buffer is allocated */
7223		trace_printk_init_buffers();
7224
7225	/* To save memory, keep the ring buffer size to its minimum */
7226	if (ring_buffer_expanded)
7227		ring_buf_size = trace_buf_size;
7228	else
7229		ring_buf_size = 1;
7230
7231	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
7232	cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
7233
7234	raw_spin_lock_init(&global_trace.start_lock);
7235
7236	/* Used for event triggers */
7237	temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
7238	if (!temp_buffer)
7239		goto out_free_cpumask;
7240
7241	if (trace_create_savedcmd() < 0)
7242		goto out_free_temp_buffer;
7243
7244	/* TODO: make the number of buffers hot pluggable with CPUS */
7245	if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
 
7246		printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
7247		WARN_ON(1);
7248		goto out_free_savedcmd;
7249	}
7250
7251	if (global_trace.buffer_disabled)
7252		tracing_off();
7253
7254	if (trace_boot_clock) {
7255		ret = tracing_set_clock(&global_trace, trace_boot_clock);
7256		if (ret < 0)
7257			pr_warn("Trace clock %s not defined, going back to default\n",
7258				trace_boot_clock);
7259	}
7260
7261	/*
7262	 * register_tracer() might reference current_trace, so it
7263	 * needs to be set before we register anything. This is
7264	 * just a bootstrap of current_trace anyway.
7265	 */
7266	global_trace.current_trace = &nop_trace;
 
 
 
7267
7268	global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 
 
 
 
7269
7270	ftrace_init_global_array_ops(&global_trace);
 
 
 
 
7271
7272	init_trace_flags_index(&global_trace);
7273
7274	register_tracer(&nop_trace);
7275
7276	/* All seems OK, enable tracing */
7277	tracing_disabled = 0;
7278
7279	atomic_notifier_chain_register(&panic_notifier_list,
7280				       &trace_panic_notifier);
7281
7282	register_die_notifier(&trace_die_notifier);
7283
7284	global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
7285
7286	INIT_LIST_HEAD(&global_trace.systems);
7287	INIT_LIST_HEAD(&global_trace.events);
7288	list_add(&global_trace.list, &ftrace_trace_arrays);
7289
7290	apply_trace_boot_options();
7291
7292	register_snapshot_cmd();
7293
7294	return 0;
7295
7296out_free_savedcmd:
7297	free_saved_cmdlines_buffer(savedcmd);
7298out_free_temp_buffer:
7299	ring_buffer_free(temp_buffer);
7300out_free_cpumask:
7301	free_cpumask_var(global_trace.tracing_cpumask);
7302out_free_buffer_mask:
7303	free_cpumask_var(tracing_buffer_mask);
7304out:
7305	return ret;
7306}
7307
7308void __init trace_init(void)
7309{
7310	if (tracepoint_printk) {
7311		tracepoint_print_iter =
7312			kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
7313		if (WARN_ON(!tracepoint_print_iter))
7314			tracepoint_printk = 0;
7315	}
7316	tracer_alloc_buffers();
7317	trace_event_init();
7318}
7319
7320__init static int clear_boot_tracer(void)
7321{
7322	/*
7323	 * The default tracer at boot buffer is an init section.
7324	 * This function is called in lateinit. If we did not
7325	 * find the boot tracer, then clear it out, to prevent
7326	 * later registration from accessing the buffer that is
7327	 * about to be freed.
7328	 */
7329	if (!default_bootup_tracer)
7330		return 0;
7331
7332	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
7333	       default_bootup_tracer);
7334	default_bootup_tracer = NULL;
7335
7336	return 0;
7337}
7338
7339fs_initcall(tracer_init_tracefs);
 
7340late_initcall(clear_boot_tracer);