1/*
   2 * ring buffer based function tracer
   3 *
   4 * Copyright (C) 2007-2008 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 William Lee Irwin III
  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/pagemap.h>
  24#include <linux/hardirq.h>
  25#include <linux/linkage.h>
  26#include <linux/uaccess.h>
  27#include <linux/kprobes.h>
  28#include <linux/ftrace.h>
  29#include <linux/module.h>
  30#include <linux/percpu.h>
  31#include <linux/splice.h>
  32#include <linux/kdebug.h>
  33#include <linux/string.h>
 
  34#include <linux/rwsem.h>
  35#include <linux/slab.h>
  36#include <linux/ctype.h>
  37#include <linux/init.h>
 
  38#include <linux/poll.h>
 
  39#include <linux/fs.h>
 
 
 
 
 
 
  40
  41#include "trace.h"
  42#include "trace_output.h"
  43
  44/*
  45 * On boot up, the ring buffer is set to the minimum size, so that
  46 * we do not waste memory on systems that are not using tracing.
  47 */
  48int ring_buffer_expanded;
  49
  50/*
  51 * We need to change this state when a selftest is running.
  52 * A selftest will lurk into the ring-buffer to count the
  53 * entries inserted during the selftest although some concurrent
  54 * insertions into the ring-buffer such as trace_printk could occurred
  55 * at the same time, giving false positive or negative results.
  56 */
  57static bool __read_mostly tracing_selftest_running;
  58
  59/*
  60 * If a tracer is running, we do not want to run SELFTEST.
 
  61 */
  62bool __read_mostly tracing_selftest_disabled;
  63
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  64/* For tracers that don't implement custom flags */
  65static struct tracer_opt dummy_tracer_opt[] = {
  66	{ }
  67};
  68
  69static struct tracer_flags dummy_tracer_flags = {
  70	.val = 0,
  71	.opts = dummy_tracer_opt
  72};
  73
  74static int dummy_set_flag(u32 old_flags, u32 bit, int set)
  75{
  76	return 0;
  77}
  78
  79/*
 
 
 
 
 
 
 
  80 * Kill all tracing for good (never come back).
  81 * It is initialized to 1 but will turn to zero if the initialization
  82 * of the tracer is successful. But that is the only place that sets
  83 * this back to zero.
  84 */
  85static int tracing_disabled = 1;
  86
  87DEFINE_PER_CPU(int, ftrace_cpu_disabled);
  88
  89static inline void ftrace_disable_cpu(void)
  90{
  91	preempt_disable();
  92	__this_cpu_inc(ftrace_cpu_disabled);
  93}
  94
  95static inline void ftrace_enable_cpu(void)
  96{
  97	__this_cpu_dec(ftrace_cpu_disabled);
  98	preempt_enable();
  99}
 100
 101cpumask_var_t __read_mostly	tracing_buffer_mask;
 102
 103/*
 104 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
 105 *
 106 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
 107 * is set, then ftrace_dump is called. This will output the contents
 108 * of the ftrace buffers to the console.  This is very useful for
 109 * capturing traces that lead to crashes and outputing it to a
 110 * serial console.
 111 *
 112 * It is default off, but you can enable it with either specifying
 113 * "ftrace_dump_on_oops" in the kernel command line, or setting
 114 * /proc/sys/kernel/ftrace_dump_on_oops
 115 * Set 1 if you want to dump buffers of all CPUs
 116 * Set 2 if you want to dump the buffer of the CPU that triggered oops
 117 */
 118
 119enum ftrace_dump_mode ftrace_dump_on_oops;
 120
 121static int tracing_set_tracer(const char *buf);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 122
 123#define MAX_TRACER_SIZE		100
 124static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
 125static char *default_bootup_tracer;
 126
 
 
 
 127static int __init set_cmdline_ftrace(char *str)
 128{
 129	strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 130	default_bootup_tracer = bootup_tracer_buf;
 131	/* We are using ftrace early, expand it */
 132	ring_buffer_expanded = 1;
 133	return 1;
 134}
 135__setup("ftrace=", set_cmdline_ftrace);
 136
 137static int __init set_ftrace_dump_on_oops(char *str)
 138{
 139	if (*str++ != '=' || !*str) {
 140		ftrace_dump_on_oops = DUMP_ALL;
 141		return 1;
 142	}
 143
 144	if (!strcmp("orig_cpu", str)) {
 145		ftrace_dump_on_oops = DUMP_ORIG;
 146                return 1;
 147        }
 148
 149        return 0;
 150}
 151__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
 152
 153unsigned long long ns2usecs(cycle_t nsec)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 154{
 155	nsec += 500;
 156	do_div(nsec, 1000);
 157	return nsec;
 158}
 159
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 160/*
 161 * The global_trace is the descriptor that holds the tracing
 162 * buffers for the live tracing. For each CPU, it contains
 163 * a link list of pages that will store trace entries. The
 164 * page descriptor of the pages in the memory is used to hold
 165 * the link list by linking the lru item in the page descriptor
 166 * to each of the pages in the buffer per CPU.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 167 *
 168 * For each active CPU there is a data field that holds the
 169 * pages for the buffer for that CPU. Each CPU has the same number
 170 * of pages allocated for its buffer.
 171 */
 172static struct trace_array	global_trace;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 173
 174static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
 
 
 
 
 
 
 
 
 175
 176int filter_current_check_discard(struct ring_buffer *buffer,
 177				 struct ftrace_event_call *call, void *rec,
 178				 struct ring_buffer_event *event)
 
 
 
 
 
 
 
 
 
 179{
 180	return filter_check_discard(call, rec, buffer, event);
 181}
 182EXPORT_SYMBOL_GPL(filter_current_check_discard);
 183
 184cycle_t ftrace_now(int cpu)
 
 
 
 
 
 
 
 
 
 
 
 
 
 185{
 186	u64 ts;
 
 
 
 
 
 
 187
 188	/* Early boot up does not have a buffer yet */
 189	if (!global_trace.buffer)
 190		return trace_clock_local();
 
 
 191
 192	ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
 193	ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 194
 195	return ts;
 
 
 
 
 
 
 
 
 
 
 196}
 197
 198/*
 199 * The max_tr is used to snapshot the global_trace when a maximum
 200 * latency is reached. Some tracers will use this to store a maximum
 201 * trace while it continues examining live traces.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 202 *
 203 * The buffers for the max_tr are set up the same as the global_trace.
 204 * When a snapshot is taken, the link list of the max_tr is swapped
 205 * with the link list of the global_trace and the buffers are reset for
 206 * the global_trace so the tracing can continue.
 207 */
 208static struct trace_array	max_tr;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 209
 210static DEFINE_PER_CPU(struct trace_array_cpu, max_tr_data);
 
 211
 212/* tracer_enabled is used to toggle activation of a tracer */
 213static int			tracer_enabled = 1;
 
 
 
 
 
 214
 215/**
 216 * tracing_is_enabled - return tracer_enabled status
 217 *
 218 * This function is used by other tracers to know the status
 219 * of the tracer_enabled flag.  Tracers may use this function
 220 * to know if it should enable their features when starting
 221 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
 
 222 */
 223int tracing_is_enabled(void)
 224{
 225	return tracer_enabled;
 
 
 
 
 
 
 226}
 227
 228/*
 229 * trace_buf_size is the size in bytes that is allocated
 230 * for a buffer. Note, the number of bytes is always rounded
 231 * to page size.
 232 *
 233 * This number is purposely set to a low number of 16384.
 234 * If the dump on oops happens, it will be much appreciated
 235 * to not have to wait for all that output. Anyway this can be
 236 * boot time and run time configurable.
 237 */
 238#define TRACE_BUF_SIZE_DEFAULT	1441792UL /* 16384 * 88 (sizeof(entry)) */
 239
 240static unsigned long		trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
 241
 242/* trace_types holds a link list of available tracers. */
 243static struct tracer		*trace_types __read_mostly;
 244
 245/* current_trace points to the tracer that is currently active */
 246static struct tracer		*current_trace __read_mostly;
 247
 248/*
 249 * trace_types_lock is used to protect the trace_types list.
 250 */
 251static DEFINE_MUTEX(trace_types_lock);
 252
 253/*
 254 * serialize the access of the ring buffer
 255 *
 256 * ring buffer serializes readers, but it is low level protection.
 257 * The validity of the events (which returns by ring_buffer_peek() ..etc)
 258 * are not protected by ring buffer.
 259 *
 260 * The content of events may become garbage if we allow other process consumes
 261 * these events concurrently:
 262 *   A) the page of the consumed events may become a normal page
 263 *      (not reader page) in ring buffer, and this page will be rewrited
 264 *      by events producer.
 265 *   B) The page of the consumed events may become a page for splice_read,
 266 *      and this page will be returned to system.
 267 *
 268 * These primitives allow multi process access to different cpu ring buffer
 269 * concurrently.
 270 *
 271 * These primitives don't distinguish read-only and read-consume access.
 272 * Multi read-only access are also serialized.
 273 */
 274
 275#ifdef CONFIG_SMP
 276static DECLARE_RWSEM(all_cpu_access_lock);
 277static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
 278
 279static inline void trace_access_lock(int cpu)
 280{
 281	if (cpu == TRACE_PIPE_ALL_CPU) {
 282		/* gain it for accessing the whole ring buffer. */
 283		down_write(&all_cpu_access_lock);
 284	} else {
 285		/* gain it for accessing a cpu ring buffer. */
 286
 287		/* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
 288		down_read(&all_cpu_access_lock);
 289
 290		/* Secondly block other access to this @cpu ring buffer. */
 291		mutex_lock(&per_cpu(cpu_access_lock, cpu));
 292	}
 293}
 294
 295static inline void trace_access_unlock(int cpu)
 296{
 297	if (cpu == TRACE_PIPE_ALL_CPU) {
 298		up_write(&all_cpu_access_lock);
 299	} else {
 300		mutex_unlock(&per_cpu(cpu_access_lock, cpu));
 301		up_read(&all_cpu_access_lock);
 302	}
 303}
 304
 305static inline void trace_access_lock_init(void)
 306{
 307	int cpu;
 308
 309	for_each_possible_cpu(cpu)
 310		mutex_init(&per_cpu(cpu_access_lock, cpu));
 311}
 312
 313#else
 314
 315static DEFINE_MUTEX(access_lock);
 316
 317static inline void trace_access_lock(int cpu)
 318{
 319	(void)cpu;
 320	mutex_lock(&access_lock);
 321}
 322
 323static inline void trace_access_unlock(int cpu)
 324{
 325	(void)cpu;
 326	mutex_unlock(&access_lock);
 327}
 328
 329static inline void trace_access_lock_init(void)
 330{
 331}
 332
 333#endif
 334
 335/* trace_wait is a waitqueue for tasks blocked on trace_poll */
 336static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
 
 
 
 
 
 
 337
 338/* trace_flags holds trace_options default values */
 339unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
 340	TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
 341	TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 342
 343static int trace_stop_count;
 344static DEFINE_SPINLOCK(tracing_start_lock);
 345
 346static void wakeup_work_handler(struct work_struct *work)
 
 
 
 
 
 
 
 
 
 
 
 347{
 348	wake_up(&trace_wait);
 
 
 
 
 
 
 
 
 
 
 
 
 
 349}
 350
 351static DECLARE_DELAYED_WORK(wakeup_work, wakeup_work_handler);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 352
 353/**
 354 * trace_wake_up - wake up tasks waiting for trace input
 
 
 
 
 355 *
 356 * Schedules a delayed work to wake up any task that is blocked on the
 357 * trace_wait queue. These is used with trace_poll for tasks polling the
 358 * trace.
 359 */
 360void trace_wake_up(void)
 361{
 362	const unsigned long delay = msecs_to_jiffies(2);
 363
 364	if (trace_flags & TRACE_ITER_BLOCK)
 
 365		return;
 366	schedule_delayed_work(&wakeup_work, delay);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 367}
 368
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 369static int __init set_buf_size(char *str)
 370{
 371	unsigned long buf_size;
 372
 373	if (!str)
 374		return 0;
 375	buf_size = memparse(str, &str);
 376	/* nr_entries can not be zero */
 377	if (buf_size == 0)
 378		return 0;
 379	trace_buf_size = buf_size;
 
 
 380	return 1;
 381}
 382__setup("trace_buf_size=", set_buf_size);
 383
 384static int __init set_tracing_thresh(char *str)
 385{
 386	unsigned long threshhold;
 387	int ret;
 388
 389	if (!str)
 390		return 0;
 391	ret = strict_strtoul(str, 0, &threshhold);
 392	if (ret < 0)
 393		return 0;
 394	tracing_thresh = threshhold * 1000;
 395	return 1;
 396}
 397__setup("tracing_thresh=", set_tracing_thresh);
 398
 399unsigned long nsecs_to_usecs(unsigned long nsecs)
 400{
 401	return nsecs / 1000;
 402}
 403
 404/* These must match the bit postions in trace_iterator_flags */
 
 
 
 
 
 
 
 
 
 405static const char *trace_options[] = {
 406	"print-parent",
 407	"sym-offset",
 408	"sym-addr",
 409	"verbose",
 410	"raw",
 411	"hex",
 412	"bin",
 413	"block",
 414	"stacktrace",
 415	"trace_printk",
 416	"ftrace_preempt",
 417	"branch",
 418	"annotate",
 419	"userstacktrace",
 420	"sym-userobj",
 421	"printk-msg-only",
 422	"context-info",
 423	"latency-format",
 424	"sleep-time",
 425	"graph-time",
 426	"record-cmd",
 427	"overwrite",
 428	"disable_on_free",
 429	NULL
 430};
 431
 432static struct {
 433	u64 (*func)(void);
 434	const char *name;
 
 435} trace_clocks[] = {
 436	{ trace_clock_local,	"local" },
 437	{ trace_clock_global,	"global" },
 
 
 
 
 
 
 
 
 438};
 439
 440int trace_clock_id;
 
 
 
 
 
 
 441
 442/*
 443 * trace_parser_get_init - gets the buffer for trace parser
 444 */
 445int trace_parser_get_init(struct trace_parser *parser, int size)
 446{
 447	memset(parser, 0, sizeof(*parser));
 448
 449	parser->buffer = kmalloc(size, GFP_KERNEL);
 450	if (!parser->buffer)
 451		return 1;
 452
 453	parser->size = size;
 454	return 0;
 455}
 456
 457/*
 458 * trace_parser_put - frees the buffer for trace parser
 459 */
 460void trace_parser_put(struct trace_parser *parser)
 461{
 462	kfree(parser->buffer);
 
 463}
 464
 465/*
 466 * trace_get_user - reads the user input string separated by  space
 467 * (matched by isspace(ch))
 468 *
 469 * For each string found the 'struct trace_parser' is updated,
 470 * and the function returns.
 471 *
 472 * Returns number of bytes read.
 473 *
 474 * See kernel/trace/trace.h for 'struct trace_parser' details.
 475 */
 476int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 477	size_t cnt, loff_t *ppos)
 478{
 479	char ch;
 480	size_t read = 0;
 481	ssize_t ret;
 482
 483	if (!*ppos)
 484		trace_parser_clear(parser);
 485
 486	ret = get_user(ch, ubuf++);
 487	if (ret)
 488		goto out;
 489
 490	read++;
 491	cnt--;
 492
 493	/*
 494	 * The parser is not finished with the last write,
 495	 * continue reading the user input without skipping spaces.
 496	 */
 497	if (!parser->cont) {
 498		/* skip white space */
 499		while (cnt && isspace(ch)) {
 500			ret = get_user(ch, ubuf++);
 501			if (ret)
 502				goto out;
 503			read++;
 504			cnt--;
 505		}
 506
 
 
 507		/* only spaces were written */
 508		if (isspace(ch)) {
 509			*ppos += read;
 510			ret = read;
 511			goto out;
 512		}
 513
 514		parser->idx = 0;
 515	}
 516
 517	/* read the non-space input */
 518	while (cnt && !isspace(ch)) {
 519		if (parser->idx < parser->size - 1)
 520			parser->buffer[parser->idx++] = ch;
 521		else {
 522			ret = -EINVAL;
 523			goto out;
 524		}
 525		ret = get_user(ch, ubuf++);
 526		if (ret)
 527			goto out;
 528		read++;
 529		cnt--;
 530	}
 531
 532	/* We either got finished input or we have to wait for another call. */
 533	if (isspace(ch)) {
 534		parser->buffer[parser->idx] = 0;
 535		parser->cont = false;
 536	} else {
 537		parser->cont = true;
 538		parser->buffer[parser->idx++] = ch;
 
 
 
 
 
 539	}
 540
 541	*ppos += read;
 542	ret = read;
 543
 544out:
 545	return ret;
 546}
 547
 548ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
 
 549{
 550	int len;
 551	int ret;
 552
 553	if (!cnt)
 554		return 0;
 555
 556	if (s->len <= s->readpos)
 557		return -EBUSY;
 558
 559	len = s->len - s->readpos;
 560	if (cnt > len)
 561		cnt = len;
 562	ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
 563	if (ret == cnt)
 564		return -EFAULT;
 565
 566	cnt -= ret;
 567
 568	s->readpos += cnt;
 569	return cnt;
 570}
 571
 572static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
 
 
 
 
 
 
 
 
 
 573{
 574	int len;
 575	void *ret;
 
 
 576
 577	if (s->len <= s->readpos)
 578		return -EBUSY;
 
 
 
 
 579
 580	len = s->len - s->readpos;
 581	if (cnt > len)
 582		cnt = len;
 583	ret = memcpy(buf, s->buffer + s->readpos, cnt);
 584	if (!ret)
 585		return -EFAULT;
 
 
 
 
 586
 587	s->readpos += cnt;
 588	return cnt;
 
 
 
 
 
 
 
 589}
 590
 591/*
 592 * ftrace_max_lock is used to protect the swapping of buffers
 593 * when taking a max snapshot. The buffers themselves are
 594 * protected by per_cpu spinlocks. But the action of the swap
 595 * needs its own lock.
 596 *
 597 * This is defined as a arch_spinlock_t in order to help
 598 * with performance when lockdep debugging is enabled.
 599 *
 600 * It is also used in other places outside the update_max_tr
 601 * so it needs to be defined outside of the
 602 * CONFIG_TRACER_MAX_TRACE.
 603 */
 604static arch_spinlock_t ftrace_max_lock =
 605	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 606
 607unsigned long __read_mostly	tracing_thresh;
 
 
 
 
 
 
 
 
 
 
 608
 609#ifdef CONFIG_TRACER_MAX_TRACE
 610unsigned long __read_mostly	tracing_max_latency;
 
 
 
 
 
 611
 612/*
 613 * Copy the new maximum trace into the separate maximum-trace
 614 * structure. (this way the maximum trace is permanently saved,
 615 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
 616 */
 617static void
 618__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 619{
 620	struct trace_array_cpu *data = tr->data[cpu];
 621	struct trace_array_cpu *max_data;
 
 
 622
 623	max_tr.cpu = cpu;
 624	max_tr.time_start = data->preempt_timestamp;
 625
 626	max_data = max_tr.data[cpu];
 627	max_data->saved_latency = tracing_max_latency;
 628	max_data->critical_start = data->critical_start;
 629	max_data->critical_end = data->critical_end;
 630
 631	memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
 632	max_data->pid = tsk->pid;
 633	max_data->uid = task_uid(tsk);
 
 
 
 
 
 
 
 
 634	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
 635	max_data->policy = tsk->policy;
 636	max_data->rt_priority = tsk->rt_priority;
 637
 638	/* record this tasks comm */
 639	tracing_record_cmdline(tsk);
 
 640}
 641
 642/**
 643 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
 644 * @tr: tracer
 645 * @tsk: the task with the latency
 646 * @cpu: The cpu that initiated the trace.
 
 647 *
 648 * Flip the buffers between the @tr and the max_tr and record information
 649 * about which task was the cause of this latency.
 650 */
 651void
 652update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 
 653{
 654	struct ring_buffer *buf = tr->buffer;
 655
 656	if (trace_stop_count)
 657		return;
 658
 659	WARN_ON_ONCE(!irqs_disabled());
 660	if (!current_trace->use_max_tr) {
 661		WARN_ON_ONCE(1);
 
 
 662		return;
 663	}
 664	arch_spin_lock(&ftrace_max_lock);
 665
 666	tr->buffer = max_tr.buffer;
 667	max_tr.buffer = buf;
 
 
 
 
 
 
 
 
 
 
 
 
 
 668
 669	__update_max_tr(tr, tsk, cpu);
 670	arch_spin_unlock(&ftrace_max_lock);
 
 671}
 672
 673/**
 674 * update_max_tr_single - only copy one trace over, and reset the rest
 675 * @tr - tracer
 676 * @tsk - task with the latency
 677 * @cpu - the cpu of the buffer to copy.
 678 *
 679 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
 680 */
 681void
 682update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 683{
 684	int ret;
 685
 686	if (trace_stop_count)
 687		return;
 688
 689	WARN_ON_ONCE(!irqs_disabled());
 690	if (!current_trace->use_max_tr) {
 691		WARN_ON_ONCE(1);
 
 692		return;
 693	}
 694
 695	arch_spin_lock(&ftrace_max_lock);
 696
 697	ftrace_disable_cpu();
 698
 699	ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
 700
 701	if (ret == -EBUSY) {
 702		/*
 703		 * We failed to swap the buffer due to a commit taking
 704		 * place on this CPU. We fail to record, but we reset
 705		 * the max trace buffer (no one writes directly to it)
 706		 * and flag that it failed.
 707		 */
 708		trace_array_printk(&max_tr, _THIS_IP_,
 709			"Failed to swap buffers due to commit in progress\n");
 710	}
 711
 712	ftrace_enable_cpu();
 713
 714	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
 715
 716	__update_max_tr(tr, tsk, cpu);
 717	arch_spin_unlock(&ftrace_max_lock);
 718}
 
 719#endif /* CONFIG_TRACER_MAX_TRACE */
 720
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 721/**
 722 * register_tracer - register a tracer with the ftrace system.
 723 * @type - the plugin for the tracer
 724 *
 725 * Register a new plugin tracer.
 726 */
 727int register_tracer(struct tracer *type)
 728__releases(kernel_lock)
 729__acquires(kernel_lock)
 730{
 731	struct tracer *t;
 732	int ret = 0;
 733
 734	if (!type->name) {
 735		pr_info("Tracer must have a name\n");
 736		return -1;
 737	}
 738
 739	if (strlen(type->name) >= MAX_TRACER_SIZE) {
 740		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
 741		return -1;
 742	}
 743
 
 
 
 
 
 
 744	mutex_lock(&trace_types_lock);
 745
 746	tracing_selftest_running = true;
 747
 748	for (t = trace_types; t; t = t->next) {
 749		if (strcmp(type->name, t->name) == 0) {
 750			/* already found */
 751			pr_info("Tracer %s already registered\n",
 752				type->name);
 753			ret = -1;
 754			goto out;
 755		}
 756	}
 757
 758	if (!type->set_flag)
 759		type->set_flag = &dummy_set_flag;
 760	if (!type->flags)
 761		type->flags = &dummy_tracer_flags;
 762	else
 763		if (!type->flags->opts)
 764			type->flags->opts = dummy_tracer_opt;
 765	if (!type->wait_pipe)
 766		type->wait_pipe = default_wait_pipe;
 767
 768
 769#ifdef CONFIG_FTRACE_STARTUP_TEST
 770	if (type->selftest && !tracing_selftest_disabled) {
 771		struct tracer *saved_tracer = current_trace;
 772		struct trace_array *tr = &global_trace;
 773
 774		/*
 775		 * Run a selftest on this tracer.
 776		 * Here we reset the trace buffer, and set the current
 777		 * tracer to be this tracer. The tracer can then run some
 778		 * internal tracing to verify that everything is in order.
 779		 * If we fail, we do not register this tracer.
 780		 */
 781		tracing_reset_online_cpus(tr);
 782
 783		current_trace = type;
 784
 785		/* If we expanded the buffers, make sure the max is expanded too */
 786		if (ring_buffer_expanded && type->use_max_tr)
 787			ring_buffer_resize(max_tr.buffer, trace_buf_size);
 788
 789		/* the test is responsible for initializing and enabling */
 790		pr_info("Testing tracer %s: ", type->name);
 791		ret = type->selftest(type, tr);
 792		/* the test is responsible for resetting too */
 793		current_trace = saved_tracer;
 794		if (ret) {
 795			printk(KERN_CONT "FAILED!\n");
 796			goto out;
 797		}
 798		/* Only reset on passing, to avoid touching corrupted buffers */
 799		tracing_reset_online_cpus(tr);
 
 
 
 800
 801		/* Shrink the max buffer again */
 802		if (ring_buffer_expanded && type->use_max_tr)
 803			ring_buffer_resize(max_tr.buffer, 1);
 804
 805		printk(KERN_CONT "PASSED\n");
 806	}
 807#endif
 808
 809	type->next = trace_types;
 810	trace_types = type;
 
 811
 812 out:
 813	tracing_selftest_running = false;
 814	mutex_unlock(&trace_types_lock);
 815
 816	if (ret || !default_bootup_tracer)
 817		goto out_unlock;
 818
 819	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
 820		goto out_unlock;
 821
 822	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
 823	/* Do we want this tracer to start on bootup? */
 824	tracing_set_tracer(type->name);
 825	default_bootup_tracer = NULL;
 
 
 
 826	/* disable other selftests, since this will break it. */
 827	tracing_selftest_disabled = 1;
 828#ifdef CONFIG_FTRACE_STARTUP_TEST
 829	printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
 830	       type->name);
 831#endif
 832
 833 out_unlock:
 834	return ret;
 835}
 836
 837void unregister_tracer(struct tracer *type)
 838{
 839	struct tracer **t;
 840
 841	mutex_lock(&trace_types_lock);
 842	for (t = &trace_types; *t; t = &(*t)->next) {
 843		if (*t == type)
 844			goto found;
 845	}
 846	pr_info("Tracer %s not registered\n", type->name);
 847	goto out;
 848
 849 found:
 850	*t = (*t)->next;
 851
 852	if (type == current_trace && tracer_enabled) {
 853		tracer_enabled = 0;
 854		tracing_stop();
 855		if (current_trace->stop)
 856			current_trace->stop(&global_trace);
 857		current_trace = &nop_trace;
 858	}
 859out:
 860	mutex_unlock(&trace_types_lock);
 861}
 862
 863static void __tracing_reset(struct ring_buffer *buffer, int cpu)
 864{
 865	ftrace_disable_cpu();
 866	ring_buffer_reset_cpu(buffer, cpu);
 867	ftrace_enable_cpu();
 868}
 869
 870void tracing_reset(struct trace_array *tr, int cpu)
 871{
 872	struct ring_buffer *buffer = tr->buffer;
 873
 874	ring_buffer_record_disable(buffer);
 875
 876	/* Make sure all commits have finished */
 877	synchronize_sched();
 878	__tracing_reset(buffer, cpu);
 879
 880	ring_buffer_record_enable(buffer);
 881}
 882
 883void tracing_reset_online_cpus(struct trace_array *tr)
 884{
 885	struct ring_buffer *buffer = tr->buffer;
 886	int cpu;
 
 
 887
 888	ring_buffer_record_disable(buffer);
 889
 890	/* Make sure all commits have finished */
 891	synchronize_sched();
 892
 893	tr->time_start = ftrace_now(tr->cpu);
 894
 895	for_each_online_cpu(cpu)
 896		__tracing_reset(buffer, cpu);
 897
 898	ring_buffer_record_enable(buffer);
 899}
 900
 901void tracing_reset_current(int cpu)
 
 902{
 903	tracing_reset(&global_trace, cpu);
 
 
 
 
 
 
 
 
 
 
 
 
 904}
 905
 906void tracing_reset_current_online_cpus(void)
 907{
 908	tracing_reset_online_cpus(&global_trace);
 
 
 909}
 910
 911#define SAVED_CMDLINES 128
 
 
 
 
 
 
 
 
 
 912#define NO_CMDLINE_MAP UINT_MAX
 913static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
 914static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
 915static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
 916static int cmdline_idx;
 
 917static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 
 
 
 
 
 
 
 
 918
 919/* temporary disable recording */
 920static atomic_t trace_record_cmdline_disabled __read_mostly;
 
 
 921
 922static void trace_init_cmdlines(void)
 923{
 924	memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
 925	memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
 926	cmdline_idx = 0;
 927}
 928
 929int is_tracing_stopped(void)
 
 930{
 931	return trace_stop_count;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 932}
 933
 934/**
 935 * ftrace_off_permanent - disable all ftrace code permanently
 936 *
 937 * This should only be called when a serious anomally has
 938 * been detected.  This will turn off the function tracing,
 939 * ring buffers, and other tracing utilites. It takes no
 940 * locks and can be called from any context.
 941 */
 942void ftrace_off_permanent(void)
 943{
 944	tracing_disabled = 1;
 945	ftrace_stop();
 946	tracing_off_permanent();
 
 
 
 
 
 
 
 
 947}
 948
 949/**
 950 * tracing_start - quick start of the tracer
 951 *
 952 * If tracing is enabled but was stopped by tracing_stop,
 953 * this will start the tracer back up.
 954 */
 955void tracing_start(void)
 956{
 957	struct ring_buffer *buffer;
 958	unsigned long flags;
 959
 960	if (tracing_disabled)
 961		return;
 962
 963	spin_lock_irqsave(&tracing_start_lock, flags);
 964	if (--trace_stop_count) {
 965		if (trace_stop_count < 0) {
 966			/* Someone screwed up their debugging */
 967			WARN_ON_ONCE(1);
 968			trace_stop_count = 0;
 969		}
 970		goto out;
 971	}
 972
 973	/* Prevent the buffers from switching */
 974	arch_spin_lock(&ftrace_max_lock);
 975
 976	buffer = global_trace.buffer;
 977	if (buffer)
 978		ring_buffer_record_enable(buffer);
 979
 980	buffer = max_tr.buffer;
 
 981	if (buffer)
 982		ring_buffer_record_enable(buffer);
 
 983
 984	arch_spin_unlock(&ftrace_max_lock);
 985
 986	ftrace_start();
 987 out:
 988	spin_unlock_irqrestore(&tracing_start_lock, flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 989}
 990
 991/**
 992 * tracing_stop - quick stop of the tracer
 993 *
 994 * Light weight way to stop tracing. Use in conjunction with
 995 * tracing_start.
 996 */
 997void tracing_stop(void)
 998{
 999	struct ring_buffer *buffer;
1000	unsigned long flags;
1001
1002	ftrace_stop();
1003	spin_lock_irqsave(&tracing_start_lock, flags);
1004	if (trace_stop_count++)
1005		goto out;
1006
1007	/* Prevent the buffers from switching */
1008	arch_spin_lock(&ftrace_max_lock);
1009
1010	buffer = global_trace.buffer;
1011	if (buffer)
1012		ring_buffer_record_disable(buffer);
1013
1014	buffer = max_tr.buffer;
 
1015	if (buffer)
1016		ring_buffer_record_disable(buffer);
 
1017
1018	arch_spin_unlock(&ftrace_max_lock);
1019
1020 out:
1021	spin_unlock_irqrestore(&tracing_start_lock, flags);
1022}
1023
1024void trace_stop_cmdline_recording(void);
 
 
 
 
 
 
 
1025
1026static void trace_save_cmdline(struct task_struct *tsk)
 
 
 
 
 
 
 
 
 
 
 
 
1027{
1028	unsigned pid, idx;
1029
1030	if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1031		return;
 
 
 
1032
1033	/*
1034	 * It's not the end of the world if we don't get
1035	 * the lock, but we also don't want to spin
1036	 * nor do we want to disable interrupts,
1037	 * so if we miss here, then better luck next time.
 
 
 
1038	 */
 
1039	if (!arch_spin_trylock(&trace_cmdline_lock))
1040		return;
1041
1042	idx = map_pid_to_cmdline[tsk->pid];
1043	if (idx == NO_CMDLINE_MAP) {
1044		idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1045
1046		/*
1047		 * Check whether the cmdline buffer at idx has a pid
1048		 * mapped. We are going to overwrite that entry so we
1049		 * need to clear the map_pid_to_cmdline. Otherwise we
1050		 * would read the new comm for the old pid.
1051		 */
1052		pid = map_cmdline_to_pid[idx];
1053		if (pid != NO_CMDLINE_MAP)
1054			map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1055
1056		map_cmdline_to_pid[idx] = tsk->pid;
1057		map_pid_to_cmdline[tsk->pid] = idx;
1058
1059		cmdline_idx = idx;
1060	}
1061
1062	memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
 
1063
1064	arch_spin_unlock(&trace_cmdline_lock);
 
 
1065}
1066
1067void trace_find_cmdline(int pid, char comm[])
1068{
1069	unsigned map;
 
1070
1071	if (!pid) {
1072		strcpy(comm, "<idle>");
1073		return;
1074	}
1075
1076	if (WARN_ON_ONCE(pid < 0)) {
1077		strcpy(comm, "<XXX>");
1078		return;
1079	}
1080
1081	if (pid > PID_MAX_DEFAULT) {
1082		strcpy(comm, "<...>");
1083		return;
 
 
 
 
 
1084	}
 
 
1085
 
 
1086	preempt_disable();
1087	arch_spin_lock(&trace_cmdline_lock);
1088	map = map_pid_to_cmdline[pid];
1089	if (map != NO_CMDLINE_MAP)
1090		strcpy(comm, saved_cmdlines[map]);
1091	else
1092		strcpy(comm, "<...>");
1093
1094	arch_spin_unlock(&trace_cmdline_lock);
1095	preempt_enable();
1096}
1097
1098void tracing_record_cmdline(struct task_struct *tsk)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1099{
1100	if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
1101	    !tracing_is_on())
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1102		return;
1103
1104	trace_save_cmdline(tsk);
1105}
1106
1107void
1108tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1109			     int pc)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1110{
1111	struct task_struct *tsk = current;
 
 
 
1112
1113	entry->preempt_count		= pc & 0xff;
1114	entry->pid			= (tsk) ? tsk->pid : 0;
1115	entry->padding			= 0;
1116	entry->flags =
1117#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1118		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1119#else
1120		TRACE_FLAG_IRQS_NOSUPPORT |
1121#endif
1122		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1123		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1124		(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
1125}
1126EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1127
1128struct ring_buffer_event *
1129trace_buffer_lock_reserve(struct ring_buffer *buffer,
1130			  int type,
1131			  unsigned long len,
1132			  unsigned long flags, int pc)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1133{
1134	struct ring_buffer_event *event;
 
 
1135
1136	event = ring_buffer_lock_reserve(buffer, len);
1137	if (event != NULL) {
1138		struct trace_entry *ent = ring_buffer_event_data(event);
 
1139
1140		tracing_generic_entry_update(ent, flags, pc);
1141		ent->type = type;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1142	}
1143
1144	return event;
 
 
1145}
1146
1147static inline void
1148__trace_buffer_unlock_commit(struct ring_buffer *buffer,
1149			     struct ring_buffer_event *event,
1150			     unsigned long flags, int pc,
1151			     int wake)
1152{
1153	ring_buffer_unlock_commit(buffer, event);
1154
1155	ftrace_trace_stack(buffer, flags, 6, pc);
1156	ftrace_trace_userstack(buffer, flags, pc);
1157
1158	if (wake)
1159		trace_wake_up();
 
1160}
1161
1162void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1163				struct ring_buffer_event *event,
1164				unsigned long flags, int pc)
 
 
 
 
 
 
1165{
1166	__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1167}
1168
 
 
1169struct ring_buffer_event *
1170trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1171				  int type, unsigned long len,
1172				  unsigned long flags, int pc)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1173{
1174	*current_rb = global_trace.buffer;
1175	return trace_buffer_lock_reserve(*current_rb,
1176					 type, len, flags, pc);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1177}
1178EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1179
1180void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1181					struct ring_buffer_event *event,
1182					unsigned long flags, int pc)
1183{
1184	__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1185}
1186EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1187
1188void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
1189				       struct ring_buffer_event *event,
1190				       unsigned long flags, int pc)
1191{
1192	__trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1193}
1194EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
1195
1196void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer,
1197					    struct ring_buffer_event *event,
1198					    unsigned long flags, int pc,
1199					    struct pt_regs *regs)
 
 
 
 
 
 
 
 
 
 
1200{
1201	ring_buffer_unlock_commit(buffer, event);
1202
1203	ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
1204	ftrace_trace_userstack(buffer, flags, pc);
 
 
 
 
 
 
1205}
1206EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit_regs);
1207
1208void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1209					 struct ring_buffer_event *event)
 
 
 
 
1210{
1211	ring_buffer_discard_commit(buffer, event);
1212}
1213EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1214
1215void
1216trace_function(struct trace_array *tr,
1217	       unsigned long ip, unsigned long parent_ip, unsigned long flags,
1218	       int pc)
1219{
1220	struct ftrace_event_call *call = &event_function;
1221	struct ring_buffer *buffer = tr->buffer;
1222	struct ring_buffer_event *event;
1223	struct ftrace_entry *entry;
1224
1225	/* If we are reading the ring buffer, don't trace */
1226	if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1227		return;
1228
1229	event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1230					  flags, pc);
1231	if (!event)
1232		return;
1233	entry	= ring_buffer_event_data(event);
1234	entry->ip			= ip;
1235	entry->parent_ip		= parent_ip;
1236
1237	if (!filter_check_discard(call, entry, buffer, event))
1238		ring_buffer_unlock_commit(buffer, event);
1239}
1240
1241void
1242ftrace(struct trace_array *tr, struct trace_array_cpu *data,
1243       unsigned long ip, unsigned long parent_ip, unsigned long flags,
1244       int pc)
1245{
1246	if (likely(!atomic_read(&data->disabled)))
1247		trace_function(tr, ip, parent_ip, flags, pc);
1248}
1249
1250#ifdef CONFIG_STACKTRACE
1251
1252#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
 
 
 
 
1253struct ftrace_stack {
1254	unsigned long		calls[FTRACE_STACK_MAX_ENTRIES];
 
 
 
 
 
1255};
1256
1257static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1258static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1259
1260static void __ftrace_trace_stack(struct ring_buffer *buffer,
1261				 unsigned long flags,
1262				 int skip, int pc, struct pt_regs *regs)
1263{
1264	struct ftrace_event_call *call = &event_kernel_stack;
1265	struct ring_buffer_event *event;
 
 
1266	struct stack_entry *entry;
1267	struct stack_trace trace;
1268	int use_stack;
1269	int size = FTRACE_STACK_ENTRIES;
1270
1271	trace.nr_entries	= 0;
1272	trace.skip		= skip;
1273
1274	/*
1275	 * Since events can happen in NMIs there's no safe way to
1276	 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1277	 * or NMI comes in, it will just have to use the default
1278	 * FTRACE_STACK_SIZE.
1279	 */
 
 
 
 
 
1280	preempt_disable_notrace();
1281
1282	use_stack = ++__get_cpu_var(ftrace_stack_reserve);
 
 
 
 
 
1283	/*
1284	 * We don't need any atomic variables, just a barrier.
1285	 * If an interrupt comes in, we don't care, because it would
1286	 * have exited and put the counter back to what we want.
1287	 * We just need a barrier to keep gcc from moving things
1288	 * around.
1289	 */
1290	barrier();
1291	if (use_stack == 1) {
1292		trace.entries		= &__get_cpu_var(ftrace_stack).calls[0];
1293		trace.max_entries	= FTRACE_STACK_MAX_ENTRIES;
1294
1295		if (regs)
1296			save_stack_trace_regs(regs, &trace);
1297		else
1298			save_stack_trace(&trace);
1299
1300		if (trace.nr_entries > size)
1301			size = trace.nr_entries;
1302	} else
1303		/* From now on, use_stack is a boolean */
1304		use_stack = 0;
1305
1306	size *= sizeof(unsigned long);
1307
1308	event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1309					  sizeof(*entry) + size, flags, pc);
 
 
1310	if (!event)
1311		goto out;
1312	entry = ring_buffer_event_data(event);
1313
1314	memset(&entry->caller, 0, size);
1315
1316	if (use_stack)
1317		memcpy(&entry->caller, trace.entries,
1318		       trace.nr_entries * sizeof(unsigned long));
1319	else {
1320		trace.max_entries	= FTRACE_STACK_ENTRIES;
1321		trace.entries		= entry->caller;
1322		if (regs)
1323			save_stack_trace_regs(regs, &trace);
1324		else
1325			save_stack_trace(&trace);
1326	}
1327
1328	entry->size = trace.nr_entries;
1329
1330	if (!filter_check_discard(call, entry, buffer, event))
1331		ring_buffer_unlock_commit(buffer, event);
1332
1333 out:
1334	/* Again, don't let gcc optimize things here */
1335	barrier();
1336	__get_cpu_var(ftrace_stack_reserve)--;
1337	preempt_enable_notrace();
1338
1339}
1340
1341void ftrace_trace_stack_regs(struct ring_buffer *buffer, unsigned long flags,
1342			     int skip, int pc, struct pt_regs *regs)
 
 
1343{
1344	if (!(trace_flags & TRACE_ITER_STACKTRACE))
1345		return;
1346
1347	__ftrace_trace_stack(buffer, flags, skip, pc, regs);
1348}
1349
1350void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1351			int skip, int pc)
1352{
1353	if (!(trace_flags & TRACE_ITER_STACKTRACE))
 
 
 
1354		return;
 
1355
1356	__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
1357}
 
 
 
 
 
 
1358
1359void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1360		   int pc)
1361{
1362	__ftrace_trace_stack(tr->buffer, flags, skip, pc, NULL);
1363}
1364
1365/**
1366 * trace_dump_stack - record a stack back trace in the trace buffer
 
1367 */
1368void trace_dump_stack(void)
1369{
1370	unsigned long flags;
1371
1372	if (tracing_disabled || tracing_selftest_running)
1373		return;
1374
1375	local_save_flags(flags);
1376
1377	/* skipping 3 traces, seems to get us at the caller of this function */
1378	__ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count(), NULL);
 
 
1379}
 
1380
 
1381static DEFINE_PER_CPU(int, user_stack_count);
1382
1383void
1384ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 
1385{
1386	struct ftrace_event_call *call = &event_user_stack;
1387	struct ring_buffer_event *event;
1388	struct userstack_entry *entry;
1389	struct stack_trace trace;
1390
1391	if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1392		return;
1393
1394	/*
1395	 * NMIs can not handle page faults, even with fix ups.
1396	 * The save user stack can (and often does) fault.
1397	 */
1398	if (unlikely(in_nmi()))
1399		return;
1400
1401	/*
1402	 * prevent recursion, since the user stack tracing may
1403	 * trigger other kernel events.
1404	 */
1405	preempt_disable();
1406	if (__this_cpu_read(user_stack_count))
1407		goto out;
1408
1409	__this_cpu_inc(user_stack_count);
1410
1411	event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1412					  sizeof(*entry), flags, pc);
1413	if (!event)
1414		goto out_drop_count;
1415	entry	= ring_buffer_event_data(event);
1416
1417	entry->tgid		= current->tgid;
1418	memset(&entry->caller, 0, sizeof(entry->caller));
1419
1420	trace.nr_entries	= 0;
1421	trace.max_entries	= FTRACE_STACK_ENTRIES;
1422	trace.skip		= 0;
1423	trace.entries		= entry->caller;
1424
1425	save_stack_trace_user(&trace);
1426	if (!filter_check_discard(call, entry, buffer, event))
1427		ring_buffer_unlock_commit(buffer, event);
1428
1429 out_drop_count:
1430	__this_cpu_dec(user_stack_count);
1431 out:
1432	preempt_enable();
1433}
1434
1435#ifdef UNUSED
1436static void __trace_userstack(struct trace_array *tr, unsigned long flags)
 
1437{
1438	ftrace_trace_userstack(tr, flags, preempt_count());
1439}
1440#endif /* UNUSED */
1441
1442#endif /* CONFIG_STACKTRACE */
1443
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1444/**
1445 * trace_vbprintk - write binary msg to tracing buffer
1446 *
 
 
1447 */
1448int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
1449{
1450	static arch_spinlock_t trace_buf_lock =
1451		(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
1452	static u32 trace_buf[TRACE_BUF_SIZE];
1453
1454	struct ftrace_event_call *call = &event_bprint;
1455	struct ring_buffer_event *event;
1456	struct ring_buffer *buffer;
1457	struct trace_array *tr = &global_trace;
1458	struct trace_array_cpu *data;
1459	struct bprint_entry *entry;
1460	unsigned long flags;
1461	int disable;
1462	int cpu, len = 0, size, pc;
1463
1464	if (unlikely(tracing_selftest_running || tracing_disabled))
1465		return 0;
1466
1467	/* Don't pollute graph traces with trace_vprintk internals */
1468	pause_graph_tracing();
1469
1470	pc = preempt_count();
1471	preempt_disable_notrace();
1472	cpu = raw_smp_processor_id();
1473	data = tr->data[cpu];
1474
1475	disable = atomic_inc_return(&data->disabled);
1476	if (unlikely(disable != 1))
1477		goto out;
 
 
1478
1479	/* Lockdep uses trace_printk for lock tracing */
1480	local_irq_save(flags);
1481	arch_spin_lock(&trace_buf_lock);
1482	len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1483
1484	if (len > TRACE_BUF_SIZE || len < 0)
1485		goto out_unlock;
1486
1487	size = sizeof(*entry) + sizeof(u32) * len;
1488	buffer = tr->buffer;
1489	event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
1490					  flags, pc);
 
1491	if (!event)
1492		goto out_unlock;
1493	entry = ring_buffer_event_data(event);
1494	entry->ip			= ip;
1495	entry->fmt			= fmt;
1496
1497	memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1498	if (!filter_check_discard(call, entry, buffer, event)) {
1499		ring_buffer_unlock_commit(buffer, event);
1500		ftrace_trace_stack(buffer, flags, 6, pc);
1501	}
1502
1503out_unlock:
1504	arch_spin_unlock(&trace_buf_lock);
1505	local_irq_restore(flags);
1506
1507out:
1508	atomic_dec_return(&data->disabled);
 
 
 
 
1509	preempt_enable_notrace();
1510	unpause_graph_tracing();
1511
1512	return len;
1513}
1514EXPORT_SYMBOL_GPL(trace_vbprintk);
1515
1516int trace_array_printk(struct trace_array *tr,
1517		       unsigned long ip, const char *fmt, ...)
1518{
1519	int ret;
1520	va_list ap;
1521
1522	if (!(trace_flags & TRACE_ITER_PRINTK))
1523		return 0;
1524
1525	va_start(ap, fmt);
1526	ret = trace_array_vprintk(tr, ip, fmt, ap);
1527	va_end(ap);
1528	return ret;
1529}
1530
1531int trace_array_vprintk(struct trace_array *tr,
1532			unsigned long ip, const char *fmt, va_list args)
1533{
1534	static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1535	static char trace_buf[TRACE_BUF_SIZE];
1536
1537	struct ftrace_event_call *call = &event_print;
1538	struct ring_buffer_event *event;
1539	struct ring_buffer *buffer;
1540	struct trace_array_cpu *data;
1541	int cpu, len = 0, size, pc;
1542	struct print_entry *entry;
1543	unsigned long irq_flags;
1544	int disable;
1545
1546	if (tracing_disabled || tracing_selftest_running)
1547		return 0;
1548
1549	pc = preempt_count();
 
 
 
1550	preempt_disable_notrace();
1551	cpu = raw_smp_processor_id();
1552	data = tr->data[cpu];
1553
1554	disable = atomic_inc_return(&data->disabled);
1555	if (unlikely(disable != 1))
1556		goto out;
1557
1558	pause_graph_tracing();
1559	raw_local_irq_save(irq_flags);
1560	arch_spin_lock(&trace_buf_lock);
1561	len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
 
 
 
1562
1563	size = sizeof(*entry) + len + 1;
1564	buffer = tr->buffer;
1565	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
1566					  irq_flags, pc);
1567	if (!event)
1568		goto out_unlock;
1569	entry = ring_buffer_event_data(event);
1570	entry->ip = ip;
1571
1572	memcpy(&entry->buf, trace_buf, len);
1573	entry->buf[len] = '\0';
1574	if (!filter_check_discard(call, entry, buffer, event)) {
1575		ring_buffer_unlock_commit(buffer, event);
1576		ftrace_trace_stack(buffer, irq_flags, 6, pc);
1577	}
1578
1579 out_unlock:
1580	arch_spin_unlock(&trace_buf_lock);
1581	raw_local_irq_restore(irq_flags);
1582	unpause_graph_tracing();
1583 out:
1584	atomic_dec_return(&data->disabled);
1585	preempt_enable_notrace();
 
1586
1587	return len;
1588}
1589
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1590int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
1591{
1592	return trace_array_vprintk(&global_trace, ip, fmt, args);
1593}
1594EXPORT_SYMBOL_GPL(trace_vprintk);
1595
1596static void trace_iterator_increment(struct trace_iterator *iter)
1597{
1598	/* Don't allow ftrace to trace into the ring buffers */
1599	ftrace_disable_cpu();
1600
1601	iter->idx++;
1602	if (iter->buffer_iter[iter->cpu])
1603		ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1604
1605	ftrace_enable_cpu();
1606}
1607
1608static struct trace_entry *
1609peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
1610		unsigned long *lost_events)
1611{
1612	struct ring_buffer_event *event;
1613	struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1614
1615	/* Don't allow ftrace to trace into the ring buffers */
1616	ftrace_disable_cpu();
1617
1618	if (buf_iter)
1619		event = ring_buffer_iter_peek(buf_iter, ts);
1620	else
1621		event = ring_buffer_peek(iter->tr->buffer, cpu, ts,
 
 
 
1622					 lost_events);
1623
1624	ftrace_enable_cpu();
1625
1626	if (event) {
1627		iter->ent_size = ring_buffer_event_length(event);
1628		return ring_buffer_event_data(event);
1629	}
1630	iter->ent_size = 0;
1631	return NULL;
1632}
1633
1634static struct trace_entry *
1635__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
1636		  unsigned long *missing_events, u64 *ent_ts)
1637{
1638	struct ring_buffer *buffer = iter->tr->buffer;
1639	struct trace_entry *ent, *next = NULL;
1640	unsigned long lost_events = 0, next_lost = 0;
1641	int cpu_file = iter->cpu_file;
1642	u64 next_ts = 0, ts;
1643	int next_cpu = -1;
 
1644	int cpu;
1645
1646	/*
1647	 * If we are in a per_cpu trace file, don't bother by iterating over
1648	 * all cpu and peek directly.
1649	 */
1650	if (cpu_file > TRACE_PIPE_ALL_CPU) {
1651		if (ring_buffer_empty_cpu(buffer, cpu_file))
1652			return NULL;
1653		ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
1654		if (ent_cpu)
1655			*ent_cpu = cpu_file;
1656
1657		return ent;
1658	}
1659
1660	for_each_tracing_cpu(cpu) {
1661
1662		if (ring_buffer_empty_cpu(buffer, cpu))
1663			continue;
1664
1665		ent = peek_next_entry(iter, cpu, &ts, &lost_events);
1666
1667		/*
1668		 * Pick the entry with the smallest timestamp:
1669		 */
1670		if (ent && (!next || ts < next_ts)) {
1671			next = ent;
1672			next_cpu = cpu;
1673			next_ts = ts;
1674			next_lost = lost_events;
 
1675		}
1676	}
1677
 
 
1678	if (ent_cpu)
1679		*ent_cpu = next_cpu;
1680
1681	if (ent_ts)
1682		*ent_ts = next_ts;
1683
1684	if (missing_events)
1685		*missing_events = next_lost;
1686
1687	return next;
1688}
1689
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1690/* Find the next real entry, without updating the iterator itself */
1691struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1692					  int *ent_cpu, u64 *ent_ts)
1693{
1694	return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1695}
1696
1697/* Find the next real entry, and increment the iterator to the next entry */
1698void *trace_find_next_entry_inc(struct trace_iterator *iter)
1699{
1700	iter->ent = __find_next_entry(iter, &iter->cpu,
1701				      &iter->lost_events, &iter->ts);
1702
1703	if (iter->ent)
1704		trace_iterator_increment(iter);
1705
1706	return iter->ent ? iter : NULL;
1707}
1708
1709static void trace_consume(struct trace_iterator *iter)
1710{
1711	/* Don't allow ftrace to trace into the ring buffers */
1712	ftrace_disable_cpu();
1713	ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts,
1714			    &iter->lost_events);
1715	ftrace_enable_cpu();
1716}
1717
1718static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1719{
1720	struct trace_iterator *iter = m->private;
1721	int i = (int)*pos;
1722	void *ent;
1723
1724	WARN_ON_ONCE(iter->leftover);
1725
1726	(*pos)++;
1727
1728	/* can't go backwards */
1729	if (iter->idx > i)
1730		return NULL;
1731
1732	if (iter->idx < 0)
1733		ent = trace_find_next_entry_inc(iter);
1734	else
1735		ent = iter;
1736
1737	while (ent && iter->idx < i)
1738		ent = trace_find_next_entry_inc(iter);
1739
1740	iter->pos = *pos;
1741
1742	return ent;
1743}
1744
1745void tracing_iter_reset(struct trace_iterator *iter, int cpu)
1746{
1747	struct trace_array *tr = iter->tr;
1748	struct ring_buffer_event *event;
1749	struct ring_buffer_iter *buf_iter;
1750	unsigned long entries = 0;
1751	u64 ts;
1752
1753	tr->data[cpu]->skipped_entries = 0;
1754
1755	if (!iter->buffer_iter[cpu])
 
1756		return;
1757
1758	buf_iter = iter->buffer_iter[cpu];
1759	ring_buffer_iter_reset(buf_iter);
1760
1761	/*
1762	 * We could have the case with the max latency tracers
1763	 * that a reset never took place on a cpu. This is evident
1764	 * by the timestamp being before the start of the buffer.
1765	 */
1766	while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
1767		if (ts >= iter->tr->time_start)
1768			break;
1769		entries++;
1770		ring_buffer_read(buf_iter, NULL);
1771	}
1772
1773	tr->data[cpu]->skipped_entries = entries;
1774}
1775
1776/*
1777 * The current tracer is copied to avoid a global locking
1778 * all around.
1779 */
1780static void *s_start(struct seq_file *m, loff_t *pos)
1781{
1782	struct trace_iterator *iter = m->private;
1783	static struct tracer *old_tracer;
1784	int cpu_file = iter->cpu_file;
1785	void *p = NULL;
1786	loff_t l = 0;
1787	int cpu;
1788
1789	/* copy the tracer to avoid using a global lock all around */
 
 
 
 
 
1790	mutex_lock(&trace_types_lock);
1791	if (unlikely(old_tracer != current_trace && current_trace)) {
1792		old_tracer = current_trace;
1793		*iter->trace = *current_trace;
1794	}
1795	mutex_unlock(&trace_types_lock);
1796
1797	atomic_inc(&trace_record_cmdline_disabled);
 
 
 
1798
1799	if (*pos != iter->pos) {
1800		iter->ent = NULL;
1801		iter->cpu = 0;
1802		iter->idx = -1;
1803
1804		ftrace_disable_cpu();
1805
1806		if (cpu_file == TRACE_PIPE_ALL_CPU) {
1807			for_each_tracing_cpu(cpu)
1808				tracing_iter_reset(iter, cpu);
1809		} else
1810			tracing_iter_reset(iter, cpu_file);
1811
1812		ftrace_enable_cpu();
1813
1814		iter->leftover = 0;
1815		for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1816			;
1817
1818	} else {
1819		/*
1820		 * If we overflowed the seq_file before, then we want
1821		 * to just reuse the trace_seq buffer again.
1822		 */
1823		if (iter->leftover)
1824			p = iter;
1825		else {
1826			l = *pos - 1;
1827			p = s_next(m, p, &l);
1828		}
1829	}
1830
1831	trace_event_read_lock();
1832	trace_access_lock(cpu_file);
1833	return p;
1834}
1835
1836static void s_stop(struct seq_file *m, void *p)
1837{
1838	struct trace_iterator *iter = m->private;
1839
1840	atomic_dec(&trace_record_cmdline_disabled);
 
 
 
 
1841	trace_access_unlock(iter->cpu_file);
1842	trace_event_read_unlock();
1843}
1844
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1845static void print_lat_help_header(struct seq_file *m)
1846{
1847	seq_puts(m, "#                  _------=> CPU#            \n");
1848	seq_puts(m, "#                 / _-----=> irqs-off        \n");
1849	seq_puts(m, "#                | / _----=> need-resched    \n");
1850	seq_puts(m, "#                || / _---=> hardirq/softirq \n");
1851	seq_puts(m, "#                ||| / _--=> preempt-depth   \n");
1852	seq_puts(m, "#                |||| /     delay             \n");
1853	seq_puts(m, "#  cmd     pid   ||||| time  |   caller      \n");
1854	seq_puts(m, "#     \\   /      |||||  \\    |   /           \n");
 
 
 
 
 
 
 
 
 
 
 
 
1855}
1856
1857static void print_func_help_header(struct seq_file *m)
 
1858{
1859	seq_puts(m, "#           TASK-PID    CPU#    TIMESTAMP  FUNCTION\n");
1860	seq_puts(m, "#              | |       |          |         |\n");
 
 
 
 
1861}
1862
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1863
1864void
1865print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1866{
1867	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1868	struct trace_array *tr = iter->tr;
1869	struct trace_array_cpu *data = tr->data[tr->cpu];
1870	struct tracer *type = current_trace;
1871	unsigned long entries = 0;
1872	unsigned long total = 0;
1873	unsigned long count;
1874	const char *name = "preemption";
1875	int cpu;
1876
1877	if (type)
1878		name = type->name;
1879
1880
1881	for_each_tracing_cpu(cpu) {
1882		count = ring_buffer_entries_cpu(tr->buffer, cpu);
1883		/*
1884		 * If this buffer has skipped entries, then we hold all
1885		 * entries for the trace and we need to ignore the
1886		 * ones before the time stamp.
1887		 */
1888		if (tr->data[cpu]->skipped_entries) {
1889			count -= tr->data[cpu]->skipped_entries;
1890			/* total is the same as the entries */
1891			total += count;
1892		} else
1893			total += count +
1894				ring_buffer_overrun_cpu(tr->buffer, cpu);
1895		entries += count;
1896	}
1897
1898	seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1899		   name, UTS_RELEASE);
1900	seq_puts(m, "# -----------------------------------"
1901		 "---------------------------------\n");
1902	seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1903		   " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1904		   nsecs_to_usecs(data->saved_latency),
1905		   entries,
1906		   total,
1907		   tr->cpu,
1908#if defined(CONFIG_PREEMPT_NONE)
1909		   "server",
1910#elif defined(CONFIG_PREEMPT_VOLUNTARY)
1911		   "desktop",
1912#elif defined(CONFIG_PREEMPT)
1913		   "preempt",
1914#else
1915		   "unknown",
1916#endif
1917		   /* These are reserved for later use */
1918		   0, 0, 0, 0);
1919#ifdef CONFIG_SMP
1920	seq_printf(m, " #P:%d)\n", num_online_cpus());
1921#else
1922	seq_puts(m, ")\n");
1923#endif
1924	seq_puts(m, "#    -----------------\n");
1925	seq_printf(m, "#    | task: %.16s-%d "
1926		   "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1927		   data->comm, data->pid, data->uid, data->nice,
 
1928		   data->policy, data->rt_priority);
1929	seq_puts(m, "#    -----------------\n");
1930
1931	if (data->critical_start) {
1932		seq_puts(m, "#  => started at: ");
1933		seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1934		trace_print_seq(m, &iter->seq);
1935		seq_puts(m, "\n#  => ended at:   ");
1936		seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1937		trace_print_seq(m, &iter->seq);
1938		seq_puts(m, "\n#\n");
1939	}
1940
1941	seq_puts(m, "#\n");
1942}
1943
1944static void test_cpu_buff_start(struct trace_iterator *iter)
1945{
1946	struct trace_seq *s = &iter->seq;
 
1947
1948	if (!(trace_flags & TRACE_ITER_ANNOTATE))
1949		return;
1950
1951	if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1952		return;
1953
1954	if (cpumask_test_cpu(iter->cpu, iter->started))
 
1955		return;
1956
1957	if (iter->tr->data[iter->cpu]->skipped_entries)
1958		return;
1959
1960	cpumask_set_cpu(iter->cpu, iter->started);
 
1961
1962	/* Don't print started cpu buffer for the first entry of the trace */
1963	if (iter->idx > 1)
1964		trace_seq_printf(s, "##### CPU %u buffer started ####\n",
1965				iter->cpu);
1966}
1967
1968static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1969{
 
1970	struct trace_seq *s = &iter->seq;
1971	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1972	struct trace_entry *entry;
1973	struct trace_event *event;
1974
1975	entry = iter->ent;
1976
1977	test_cpu_buff_start(iter);
1978
1979	event = ftrace_find_event(entry->type);
1980
1981	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1982		if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1983			if (!trace_print_lat_context(iter))
1984				goto partial;
1985		} else {
1986			if (!trace_print_context(iter))
1987				goto partial;
1988		}
1989	}
1990
 
 
 
1991	if (event)
1992		return event->funcs->trace(iter, sym_flags, event);
1993
1994	if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1995		goto partial;
1996
1997	return TRACE_TYPE_HANDLED;
1998partial:
1999	return TRACE_TYPE_PARTIAL_LINE;
2000}
2001
2002static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2003{
 
2004	struct trace_seq *s = &iter->seq;
2005	struct trace_entry *entry;
2006	struct trace_event *event;
2007
2008	entry = iter->ent;
2009
2010	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2011		if (!trace_seq_printf(s, "%d %d %llu ",
2012				      entry->pid, iter->cpu, iter->ts))
2013			goto partial;
2014	}
 
2015
2016	event = ftrace_find_event(entry->type);
2017	if (event)
2018		return event->funcs->raw(iter, 0, event);
2019
2020	if (!trace_seq_printf(s, "%d ?\n", entry->type))
2021		goto partial;
2022
2023	return TRACE_TYPE_HANDLED;
2024partial:
2025	return TRACE_TYPE_PARTIAL_LINE;
2026}
2027
2028static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2029{
 
2030	struct trace_seq *s = &iter->seq;
2031	unsigned char newline = '\n';
2032	struct trace_entry *entry;
2033	struct trace_event *event;
2034
2035	entry = iter->ent;
2036
2037	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2038		SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
2039		SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
2040		SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
 
 
2041	}
2042
2043	event = ftrace_find_event(entry->type);
2044	if (event) {
2045		enum print_line_t ret = event->funcs->hex(iter, 0, event);
2046		if (ret != TRACE_TYPE_HANDLED)
2047			return ret;
2048	}
2049
2050	SEQ_PUT_FIELD_RET(s, newline);
2051
2052	return TRACE_TYPE_HANDLED;
2053}
2054
2055static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2056{
 
2057	struct trace_seq *s = &iter->seq;
2058	struct trace_entry *entry;
2059	struct trace_event *event;
2060
2061	entry = iter->ent;
2062
2063	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2064		SEQ_PUT_FIELD_RET(s, entry->pid);
2065		SEQ_PUT_FIELD_RET(s, iter->cpu);
2066		SEQ_PUT_FIELD_RET(s, iter->ts);
 
 
2067	}
2068
2069	event = ftrace_find_event(entry->type);
2070	return event ? event->funcs->binary(iter, 0, event) :
2071		TRACE_TYPE_HANDLED;
2072}
2073
2074int trace_empty(struct trace_iterator *iter)
2075{
 
2076	int cpu;
2077
2078	/* If we are looking at one CPU buffer, only check that one */
2079	if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
2080		cpu = iter->cpu_file;
2081		if (iter->buffer_iter[cpu]) {
2082			if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
 
2083				return 0;
2084		} else {
2085			if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
2086				return 0;
2087		}
2088		return 1;
2089	}
2090
2091	for_each_tracing_cpu(cpu) {
2092		if (iter->buffer_iter[cpu]) {
2093			if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
 
2094				return 0;
2095		} else {
2096			if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
2097				return 0;
2098		}
2099	}
2100
2101	return 1;
2102}
2103
2104/*  Called with trace_event_read_lock() held. */
2105enum print_line_t print_trace_line(struct trace_iterator *iter)
2106{
 
 
2107	enum print_line_t ret;
2108
2109	if (iter->lost_events &&
2110	    !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2111				 iter->cpu, iter->lost_events))
2112		return TRACE_TYPE_PARTIAL_LINE;
 
 
 
 
 
 
2113
2114	if (iter->trace && iter->trace->print_line) {
2115		ret = iter->trace->print_line(iter);
2116		if (ret != TRACE_TYPE_UNHANDLED)
2117			return ret;
2118	}
2119
 
 
 
 
 
2120	if (iter->ent->type == TRACE_BPRINT &&
2121			trace_flags & TRACE_ITER_PRINTK &&
2122			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2123		return trace_print_bprintk_msg_only(iter);
2124
2125	if (iter->ent->type == TRACE_PRINT &&
2126			trace_flags & TRACE_ITER_PRINTK &&
2127			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2128		return trace_print_printk_msg_only(iter);
2129
2130	if (trace_flags & TRACE_ITER_BIN)
2131		return print_bin_fmt(iter);
2132
2133	if (trace_flags & TRACE_ITER_HEX)
2134		return print_hex_fmt(iter);
2135
2136	if (trace_flags & TRACE_ITER_RAW)
2137		return print_raw_fmt(iter);
2138
2139	return print_trace_fmt(iter);
2140}
2141
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2142void trace_default_header(struct seq_file *m)
2143{
2144	struct trace_iterator *iter = m->private;
 
 
2145
2146	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2147		return;
2148
2149	if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2150		/* print nothing if the buffers are empty */
2151		if (trace_empty(iter))
2152			return;
2153		print_trace_header(m, iter);
2154		if (!(trace_flags & TRACE_ITER_VERBOSE))
2155			print_lat_help_header(m);
2156	} else {
2157		if (!(trace_flags & TRACE_ITER_VERBOSE))
2158			print_func_help_header(m);
 
 
 
 
 
 
2159	}
2160}
2161
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2162static int s_show(struct seq_file *m, void *v)
2163{
2164	struct trace_iterator *iter = v;
2165	int ret;
2166
2167	if (iter->ent == NULL) {
2168		if (iter->tr) {
2169			seq_printf(m, "# tracer: %s\n", iter->trace->name);
2170			seq_puts(m, "#\n");
 
2171		}
2172		if (iter->trace && iter->trace->print_header)
 
 
2173			iter->trace->print_header(m);
2174		else
2175			trace_default_header(m);
2176
2177	} else if (iter->leftover) {
2178		/*
2179		 * If we filled the seq_file buffer earlier, we
2180		 * want to just show it now.
2181		 */
2182		ret = trace_print_seq(m, &iter->seq);
2183
2184		/* ret should this time be zero, but you never know */
2185		iter->leftover = ret;
2186
2187	} else {
2188		print_trace_line(iter);
2189		ret = trace_print_seq(m, &iter->seq);
2190		/*
2191		 * If we overflow the seq_file buffer, then it will
2192		 * ask us for this data again at start up.
2193		 * Use that instead.
2194		 *  ret is 0 if seq_file write succeeded.
2195		 *        -1 otherwise.
2196		 */
2197		iter->leftover = ret;
2198	}
2199
2200	return 0;
2201}
2202
 
 
 
 
 
 
 
 
 
 
 
2203static const struct seq_operations tracer_seq_ops = {
2204	.start		= s_start,
2205	.next		= s_next,
2206	.stop		= s_stop,
2207	.show		= s_show,
2208};
2209
2210static struct trace_iterator *
2211__tracing_open(struct inode *inode, struct file *file)
2212{
2213	long cpu_file = (long) inode->i_private;
2214	void *fail_ret = ERR_PTR(-ENOMEM);
2215	struct trace_iterator *iter;
2216	struct seq_file *m;
2217	int cpu, ret;
2218
2219	if (tracing_disabled)
2220		return ERR_PTR(-ENODEV);
2221
2222	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2223	if (!iter)
2224		return ERR_PTR(-ENOMEM);
2225
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2226	/*
2227	 * We make a copy of the current tracer to avoid concurrent
2228	 * changes on it while we are reading.
2229	 */
2230	mutex_lock(&trace_types_lock);
2231	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2232	if (!iter->trace)
2233		goto fail;
2234
2235	if (current_trace)
2236		*iter->trace = *current_trace;
2237
2238	if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2239		goto fail;
2240
2241	if (current_trace && current_trace->print_max)
2242		iter->tr = &max_tr;
 
 
 
 
2243	else
2244		iter->tr = &global_trace;
 
 
2245	iter->pos = -1;
 
2246	mutex_init(&iter->mutex);
2247	iter->cpu_file = cpu_file;
2248
2249	/* Notify the tracer early; before we stop tracing. */
2250	if (iter->trace && iter->trace->open)
2251		iter->trace->open(iter);
2252
2253	/* Annotate start of buffers if we had overruns */
2254	if (ring_buffer_overruns(iter->tr->buffer))
2255		iter->iter_flags |= TRACE_FILE_ANNOTATE;
2256
2257	/* stop the trace while dumping */
2258	tracing_stop();
 
 
 
 
 
 
 
 
2259
2260	if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
2261		for_each_tracing_cpu(cpu) {
2262			iter->buffer_iter[cpu] =
2263				ring_buffer_read_prepare(iter->tr->buffer, cpu);
 
2264		}
2265		ring_buffer_read_prepare_sync();
2266		for_each_tracing_cpu(cpu) {
2267			ring_buffer_read_start(iter->buffer_iter[cpu]);
2268			tracing_iter_reset(iter, cpu);
2269		}
2270	} else {
2271		cpu = iter->cpu_file;
2272		iter->buffer_iter[cpu] =
2273			ring_buffer_read_prepare(iter->tr->buffer, cpu);
 
2274		ring_buffer_read_prepare_sync();
2275		ring_buffer_read_start(iter->buffer_iter[cpu]);
2276		tracing_iter_reset(iter, cpu);
2277	}
2278
2279	ret = seq_open(file, &tracer_seq_ops);
2280	if (ret < 0) {
2281		fail_ret = ERR_PTR(ret);
2282		goto fail_buffer;
2283	}
2284
2285	m = file->private_data;
2286	m->private = iter;
2287
2288	mutex_unlock(&trace_types_lock);
2289
2290	return iter;
2291
2292 fail_buffer:
2293	for_each_tracing_cpu(cpu) {
2294		if (iter->buffer_iter[cpu])
2295			ring_buffer_read_finish(iter->buffer_iter[cpu]);
2296	}
2297	free_cpumask_var(iter->started);
2298	tracing_start();
2299 fail:
2300	mutex_unlock(&trace_types_lock);
2301	kfree(iter->trace);
2302	kfree(iter);
2303
2304	return fail_ret;
 
 
2305}
2306
2307int tracing_open_generic(struct inode *inode, struct file *filp)
2308{
2309	if (tracing_disabled)
2310		return -ENODEV;
 
 
 
2311
2312	filp->private_data = inode->i_private;
2313	return 0;
2314}
2315
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2316static int tracing_release(struct inode *inode, struct file *file)
2317{
 
2318	struct seq_file *m = file->private_data;
2319	struct trace_iterator *iter;
2320	int cpu;
2321
2322	if (!(file->f_mode & FMODE_READ))
 
2323		return 0;
 
2324
 
2325	iter = m->private;
2326
2327	mutex_lock(&trace_types_lock);
 
2328	for_each_tracing_cpu(cpu) {
2329		if (iter->buffer_iter[cpu])
2330			ring_buffer_read_finish(iter->buffer_iter[cpu]);
2331	}
2332
2333	if (iter->trace && iter->trace->close)
2334		iter->trace->close(iter);
2335
2336	/* reenable tracing if it was previously enabled */
2337	tracing_start();
 
 
 
 
2338	mutex_unlock(&trace_types_lock);
2339
2340	seq_release(inode, file);
2341	mutex_destroy(&iter->mutex);
2342	free_cpumask_var(iter->started);
 
 
2343	kfree(iter->trace);
2344	kfree(iter);
 
 
2345	return 0;
2346}
2347
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2348static int tracing_open(struct inode *inode, struct file *file)
2349{
 
2350	struct trace_iterator *iter;
2351	int ret = 0;
 
 
 
 
2352
2353	/* If this file was open for write, then erase contents */
2354	if ((file->f_mode & FMODE_WRITE) &&
2355	    (file->f_flags & O_TRUNC)) {
2356		long cpu = (long) inode->i_private;
2357
2358		if (cpu == TRACE_PIPE_ALL_CPU)
2359			tracing_reset_online_cpus(&global_trace);
 
 
 
 
 
2360		else
2361			tracing_reset(&global_trace, cpu);
2362	}
2363
2364	if (file->f_mode & FMODE_READ) {
2365		iter = __tracing_open(inode, file);
2366		if (IS_ERR(iter))
2367			ret = PTR_ERR(iter);
2368		else if (trace_flags & TRACE_ITER_LATENCY_FMT)
2369			iter->iter_flags |= TRACE_FILE_LAT_FMT;
2370	}
 
 
 
 
2371	return ret;
2372}
2373
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2374static void *
2375t_next(struct seq_file *m, void *v, loff_t *pos)
2376{
 
2377	struct tracer *t = v;
2378
2379	(*pos)++;
2380
2381	if (t)
2382		t = t->next;
2383
2384	return t;
2385}
2386
2387static void *t_start(struct seq_file *m, loff_t *pos)
2388{
 
2389	struct tracer *t;
2390	loff_t l = 0;
2391
2392	mutex_lock(&trace_types_lock);
2393	for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
2394		;
 
 
2395
2396	return t;
2397}
2398
2399static void t_stop(struct seq_file *m, void *p)
2400{
2401	mutex_unlock(&trace_types_lock);
2402}
2403
2404static int t_show(struct seq_file *m, void *v)
2405{
2406	struct tracer *t = v;
2407
2408	if (!t)
2409		return 0;
2410
2411	seq_printf(m, "%s", t->name);
2412	if (t->next)
2413		seq_putc(m, ' ');
2414	else
2415		seq_putc(m, '\n');
2416
2417	return 0;
2418}
2419
2420static const struct seq_operations show_traces_seq_ops = {
2421	.start		= t_start,
2422	.next		= t_next,
2423	.stop		= t_stop,
2424	.show		= t_show,
2425};
2426
2427static int show_traces_open(struct inode *inode, struct file *file)
2428{
2429	if (tracing_disabled)
2430		return -ENODEV;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2431
2432	return seq_open(file, &show_traces_seq_ops);
 
2433}
2434
2435static ssize_t
2436tracing_write_stub(struct file *filp, const char __user *ubuf,
2437		   size_t count, loff_t *ppos)
2438{
2439	return count;
2440}
2441
2442static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
2443{
 
 
2444	if (file->f_mode & FMODE_READ)
2445		return seq_lseek(file, offset, origin);
2446	else
2447		return 0;
 
 
2448}
2449
2450static const struct file_operations tracing_fops = {
2451	.open		= tracing_open,
2452	.read		= seq_read,
2453	.write		= tracing_write_stub,
2454	.llseek		= tracing_seek,
2455	.release	= tracing_release,
2456};
2457
2458static const struct file_operations show_traces_fops = {
2459	.open		= show_traces_open,
2460	.read		= seq_read,
2461	.release	= seq_release,
2462	.llseek		= seq_lseek,
 
2463};
2464
2465/*
2466 * Only trace on a CPU if the bitmask is set:
2467 */
2468static cpumask_var_t tracing_cpumask;
2469
2470/*
2471 * The tracer itself will not take this lock, but still we want
2472 * to provide a consistent cpumask to user-space:
2473 */
2474static DEFINE_MUTEX(tracing_cpumask_update_lock);
2475
2476/*
2477 * Temporary storage for the character representation of the
2478 * CPU bitmask (and one more byte for the newline):
2479 */
2480static char mask_str[NR_CPUS + 1];
2481
2482static ssize_t
2483tracing_cpumask_read(struct file *filp, char __user *ubuf,
2484		     size_t count, loff_t *ppos)
2485{
 
 
2486	int len;
2487
2488	mutex_lock(&tracing_cpumask_update_lock);
 
 
 
 
2489
2490	len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2491	if (count - len < 2) {
 
2492		count = -EINVAL;
2493		goto out_err;
2494	}
2495	len += sprintf(mask_str + len, "\n");
2496	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2497
2498out_err:
2499	mutex_unlock(&tracing_cpumask_update_lock);
2500
2501	return count;
2502}
2503
2504static ssize_t
2505tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2506		      size_t count, loff_t *ppos)
2507{
2508	int err, cpu;
2509	cpumask_var_t tracing_cpumask_new;
2510
2511	if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2512		return -ENOMEM;
2513
2514	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2515	if (err)
2516		goto err_unlock;
2517
2518	mutex_lock(&tracing_cpumask_update_lock);
 
2519
2520	local_irq_disable();
2521	arch_spin_lock(&ftrace_max_lock);
2522	for_each_tracing_cpu(cpu) {
2523		/*
2524		 * Increase/decrease the disabled counter if we are
2525		 * about to flip a bit in the cpumask:
2526		 */
2527		if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2528				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2529			atomic_inc(&global_trace.data[cpu]->disabled);
 
2530		}
2531		if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2532				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2533			atomic_dec(&global_trace.data[cpu]->disabled);
 
2534		}
2535	}
2536	arch_spin_unlock(&ftrace_max_lock);
2537	local_irq_enable();
2538
2539	cpumask_copy(tracing_cpumask, tracing_cpumask_new);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2540
2541	mutex_unlock(&tracing_cpumask_update_lock);
2542	free_cpumask_var(tracing_cpumask_new);
2543
2544	return count;
2545
2546err_unlock:
2547	free_cpumask_var(tracing_cpumask_new);
2548
2549	return err;
2550}
2551
2552static const struct file_operations tracing_cpumask_fops = {
2553	.open		= tracing_open_generic,
2554	.read		= tracing_cpumask_read,
2555	.write		= tracing_cpumask_write,
 
2556	.llseek		= generic_file_llseek,
2557};
2558
2559static int tracing_trace_options_show(struct seq_file *m, void *v)
2560{
2561	struct tracer_opt *trace_opts;
 
2562	u32 tracer_flags;
2563	int i;
2564
2565	mutex_lock(&trace_types_lock);
2566	tracer_flags = current_trace->flags->val;
2567	trace_opts = current_trace->flags->opts;
2568
2569	for (i = 0; trace_options[i]; i++) {
2570		if (trace_flags & (1 << i))
2571			seq_printf(m, "%s\n", trace_options[i]);
2572		else
2573			seq_printf(m, "no%s\n", trace_options[i]);
2574	}
2575
2576	for (i = 0; trace_opts[i].name; i++) {
2577		if (tracer_flags & trace_opts[i].bit)
2578			seq_printf(m, "%s\n", trace_opts[i].name);
2579		else
2580			seq_printf(m, "no%s\n", trace_opts[i].name);
2581	}
2582	mutex_unlock(&trace_types_lock);
2583
2584	return 0;
2585}
2586
2587static int __set_tracer_option(struct tracer *trace,
2588			       struct tracer_flags *tracer_flags,
2589			       struct tracer_opt *opts, int neg)
2590{
 
2591	int ret;
2592
2593	ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
2594	if (ret)
2595		return ret;
2596
2597	if (neg)
2598		tracer_flags->val &= ~opts->bit;
2599	else
2600		tracer_flags->val |= opts->bit;
2601	return 0;
2602}
2603
2604/* Try to assign a tracer specific option */
2605static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2606{
 
2607	struct tracer_flags *tracer_flags = trace->flags;
2608	struct tracer_opt *opts = NULL;
2609	int i;
2610
2611	for (i = 0; tracer_flags->opts[i].name; i++) {
2612		opts = &tracer_flags->opts[i];
2613
2614		if (strcmp(cmp, opts->name) == 0)
2615			return __set_tracer_option(trace, trace->flags,
2616						   opts, neg);
2617	}
2618
2619	return -EINVAL;
2620}
2621
2622static void set_tracer_flags(unsigned int mask, int enabled)
 
 
 
 
 
 
 
 
 
2623{
 
 
 
 
 
 
2624	/* do nothing if flag is already set */
2625	if (!!(trace_flags & mask) == !!enabled)
2626		return;
 
 
 
 
 
2627
2628	if (enabled)
2629		trace_flags |= mask;
2630	else
2631		trace_flags &= ~mask;
2632
2633	if (mask == TRACE_ITER_RECORD_CMD)
2634		trace_event_enable_cmd_record(enabled);
2635
2636	if (mask == TRACE_ITER_OVERWRITE)
2637		ring_buffer_change_overwrite(global_trace.buffer, enabled);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2638}
2639
2640static ssize_t
2641tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2642			size_t cnt, loff_t *ppos)
2643{
 
 
2644	char buf[64];
2645	char *cmp;
2646	int neg = 0;
2647	int ret;
2648	int i;
2649
2650	if (cnt >= sizeof(buf))
2651		return -EINVAL;
2652
2653	if (copy_from_user(&buf, ubuf, cnt))
2654		return -EFAULT;
2655
2656	buf[cnt] = 0;
2657	cmp = strstrip(buf);
2658
2659	if (strncmp(cmp, "no", 2) == 0) {
2660		neg = 1;
2661		cmp += 2;
2662	}
2663
2664	for (i = 0; trace_options[i]; i++) {
2665		if (strcmp(cmp, trace_options[i]) == 0) {
2666			set_tracer_flags(1 << i, !neg);
2667			break;
2668		}
2669	}
2670
2671	/* If no option could be set, test the specific tracer options */
2672	if (!trace_options[i]) {
2673		mutex_lock(&trace_types_lock);
2674		ret = set_tracer_option(current_trace, cmp, neg);
2675		mutex_unlock(&trace_types_lock);
2676		if (ret)
2677			return ret;
2678	}
2679
2680	*ppos += cnt;
2681
2682	return cnt;
2683}
2684
2685static int tracing_trace_options_open(struct inode *inode, struct file *file)
2686{
2687	if (tracing_disabled)
2688		return -ENODEV;
2689	return single_open(file, tracing_trace_options_show, NULL);
 
 
 
 
 
 
 
 
 
2690}
2691
2692static const struct file_operations tracing_iter_fops = {
2693	.open		= tracing_trace_options_open,
2694	.read		= seq_read,
2695	.llseek		= seq_lseek,
2696	.release	= single_release,
2697	.write		= tracing_trace_options_write,
2698};
2699
2700static const char readme_msg[] =
2701	"tracing mini-HOWTO:\n\n"
2702	"# mount -t debugfs nodev /sys/kernel/debug\n\n"
2703	"# cat /sys/kernel/debug/tracing/available_tracers\n"
2704	"wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2705	"# cat /sys/kernel/debug/tracing/current_tracer\n"
2706	"nop\n"
2707	"# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2708	"# cat /sys/kernel/debug/tracing/current_tracer\n"
2709	"sched_switch\n"
2710	"# cat /sys/kernel/debug/tracing/trace_options\n"
2711	"noprint-parent nosym-offset nosym-addr noverbose\n"
2712	"# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2713	"# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2714	"# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2715	"# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2716;
2717
2718static ssize_t
2719tracing_readme_read(struct file *filp, char __user *ubuf,
2720		       size_t cnt, loff_t *ppos)
2721{
2722	return simple_read_from_buffer(ubuf, cnt, ppos,
2723					readme_msg, strlen(readme_msg));
2724}
2725
2726static const struct file_operations tracing_readme_fops = {
2727	.open		= tracing_open_generic,
2728	.read		= tracing_readme_read,
2729	.llseek		= generic_file_llseek,
2730};
2731
2732static ssize_t
2733tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
2734				size_t cnt, loff_t *ppos)
2735{
2736	char *buf_comm;
2737	char *file_buf;
2738	char *buf;
2739	int len = 0;
2740	int pid;
2741	int i;
2742
2743	file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
2744	if (!file_buf)
2745		return -ENOMEM;
2746
2747	buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
2748	if (!buf_comm) {
2749		kfree(file_buf);
2750		return -ENOMEM;
2751	}
 
2752
2753	buf = file_buf;
 
 
2754
2755	for (i = 0; i < SAVED_CMDLINES; i++) {
2756		int r;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2757
2758		pid = map_cmdline_to_pid[i];
2759		if (pid == -1 || pid == NO_CMDLINE_MAP)
 
 
 
 
 
 
2760			continue;
2761
2762		trace_find_cmdline(pid, buf_comm);
2763		r = sprintf(buf, "%d %s\n", pid, buf_comm);
2764		buf += r;
2765		len += r;
2766	}
2767
2768	len = simple_read_from_buffer(ubuf, cnt, ppos,
2769				      file_buf, len);
 
 
 
 
 
 
 
 
2770
2771	kfree(file_buf);
2772	kfree(buf_comm);
 
 
 
 
2773
2774	return len;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2775}
2776
2777static const struct file_operations tracing_saved_cmdlines_fops = {
2778    .open       = tracing_open_generic,
2779    .read       = tracing_saved_cmdlines_read,
2780    .llseek	= generic_file_llseek,
 
2781};
2782
2783static ssize_t
2784tracing_ctrl_read(struct file *filp, char __user *ubuf,
2785		  size_t cnt, loff_t *ppos)
2786{
2787	char buf[64];
2788	int r;
2789
2790	r = sprintf(buf, "%u\n", tracer_enabled);
 
 
 
 
 
2791	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2792}
2793
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2794static ssize_t
2795tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2796		   size_t cnt, loff_t *ppos)
2797{
2798	struct trace_array *tr = filp->private_data;
2799	unsigned long val;
2800	int ret;
2801
2802	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
2803	if (ret)
2804		return ret;
2805
2806	val = !!val;
 
 
2807
2808	mutex_lock(&trace_types_lock);
2809	if (tracer_enabled ^ val) {
 
2810
2811		/* Only need to warn if this is used to change the state */
2812		WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2813
2814		if (val) {
2815			tracer_enabled = 1;
2816			if (current_trace->start)
2817				current_trace->start(tr);
2818			tracing_start();
2819		} else {
2820			tracer_enabled = 0;
2821			tracing_stop();
2822			if (current_trace->stop)
2823				current_trace->stop(tr);
2824		}
 
2825	}
2826	mutex_unlock(&trace_types_lock);
 
 
2827
2828	*ppos += cnt;
 
 
 
 
2829
2830	return cnt;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2831}
2832
2833static ssize_t
2834tracing_set_trace_read(struct file *filp, char __user *ubuf,
2835		       size_t cnt, loff_t *ppos)
2836{
 
2837	char buf[MAX_TRACER_SIZE+2];
2838	int r;
2839
2840	mutex_lock(&trace_types_lock);
2841	if (current_trace)
2842		r = sprintf(buf, "%s\n", current_trace->name);
2843	else
2844		r = sprintf(buf, "\n");
2845	mutex_unlock(&trace_types_lock);
2846
2847	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2848}
2849
2850int tracer_init(struct tracer *t, struct trace_array *tr)
2851{
2852	tracing_reset_online_cpus(tr);
2853	return t->init(tr);
2854}
2855
2856static int __tracing_resize_ring_buffer(unsigned long size)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2857{
2858	int ret;
2859
2860	/*
2861	 * If kernel or user changes the size of the ring buffer
2862	 * we use the size that was given, and we can forget about
2863	 * expanding it later.
2864	 */
2865	ring_buffer_expanded = 1;
 
 
 
 
2866
2867	ret = ring_buffer_resize(global_trace.buffer, size);
2868	if (ret < 0)
2869		return ret;
2870
2871	if (!current_trace->use_max_tr)
 
 
2872		goto out;
2873
2874	ret = ring_buffer_resize(max_tr.buffer, size);
2875	if (ret < 0) {
2876		int r;
2877
2878		r = ring_buffer_resize(global_trace.buffer,
2879				       global_trace.entries);
2880		if (r < 0) {
2881			/*
2882			 * AARGH! We are left with different
2883			 * size max buffer!!!!
2884			 * The max buffer is our "snapshot" buffer.
2885			 * When a tracer needs a snapshot (one of the
2886			 * latency tracers), it swaps the max buffer
2887			 * with the saved snap shot. We succeeded to
2888			 * update the size of the main buffer, but failed to
2889			 * update the size of the max buffer. But when we tried
2890			 * to reset the main buffer to the original size, we
2891			 * failed there too. This is very unlikely to
2892			 * happen, but if it does, warn and kill all
2893			 * tracing.
2894			 */
2895			WARN_ON(1);
2896			tracing_disabled = 1;
2897		}
2898		return ret;
2899	}
2900
2901	max_tr.entries = size;
 
 
 
 
2902 out:
2903	global_trace.entries = size;
 
 
 
 
 
2904
2905	return ret;
2906}
2907
2908static ssize_t tracing_resize_ring_buffer(unsigned long size)
 
2909{
2910	int cpu, ret = size;
2911
2912	mutex_lock(&trace_types_lock);
2913
2914	tracing_stop();
2915
2916	/* disable all cpu buffers */
2917	for_each_tracing_cpu(cpu) {
2918		if (global_trace.data[cpu])
2919			atomic_inc(&global_trace.data[cpu]->disabled);
2920		if (max_tr.data[cpu])
2921			atomic_inc(&max_tr.data[cpu]->disabled);
2922	}
2923
2924	if (size != global_trace.entries)
2925		ret = __tracing_resize_ring_buffer(size);
2926
2927	if (ret < 0)
2928		ret = -ENOMEM;
2929
2930	for_each_tracing_cpu(cpu) {
2931		if (global_trace.data[cpu])
2932			atomic_dec(&global_trace.data[cpu]->disabled);
2933		if (max_tr.data[cpu])
2934			atomic_dec(&max_tr.data[cpu]->disabled);
2935	}
2936
2937	tracing_start();
2938	mutex_unlock(&trace_types_lock);
2939
2940	return ret;
2941}
2942
2943
2944/**
2945 * tracing_update_buffers - used by tracing facility to expand ring buffers
2946 *
2947 * To save on memory when the tracing is never used on a system with it
2948 * configured in. The ring buffers are set to a minimum size. But once
2949 * a user starts to use the tracing facility, then they need to grow
2950 * to their default size.
2951 *
2952 * This function is to be called when a tracer is about to be used.
2953 */
2954int tracing_update_buffers(void)
2955{
2956	int ret = 0;
2957
2958	mutex_lock(&trace_types_lock);
2959	if (!ring_buffer_expanded)
2960		ret = __tracing_resize_ring_buffer(trace_buf_size);
 
2961	mutex_unlock(&trace_types_lock);
2962
2963	return ret;
2964}
2965
2966struct trace_option_dentry;
2967
2968static struct trace_option_dentry *
2969create_trace_option_files(struct tracer *tracer);
2970
2971static void
2972destroy_trace_option_files(struct trace_option_dentry *topts);
2973
2974static int tracing_set_tracer(const char *buf)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2975{
2976	static struct trace_option_dentry *topts;
2977	struct trace_array *tr = &global_trace;
2978	struct tracer *t;
 
 
 
2979	int ret = 0;
2980
2981	mutex_lock(&trace_types_lock);
2982
2983	if (!ring_buffer_expanded) {
2984		ret = __tracing_resize_ring_buffer(trace_buf_size);
 
2985		if (ret < 0)
2986			goto out;
2987		ret = 0;
2988	}
2989
2990	for (t = trace_types; t; t = t->next) {
2991		if (strcmp(t->name, buf) == 0)
2992			break;
2993	}
2994	if (!t) {
2995		ret = -EINVAL;
2996		goto out;
2997	}
2998	if (t == current_trace)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2999		goto out;
 
 
 
 
 
 
 
3000
3001	trace_branch_disable();
3002	if (current_trace && current_trace->reset)
3003		current_trace->reset(tr);
3004	if (current_trace && current_trace->use_max_tr) {
 
 
 
 
 
 
 
 
 
 
3005		/*
3006		 * We don't free the ring buffer. instead, resize it because
3007		 * The max_tr ring buffer has some state (e.g. ring->clock) and
3008		 * we want preserve it.
 
 
3009		 */
3010		ring_buffer_resize(max_tr.buffer, 1);
3011		max_tr.entries = 1;
3012	}
3013	destroy_trace_option_files(topts);
3014
3015	current_trace = t;
3016
3017	topts = create_trace_option_files(current_trace);
3018	if (current_trace->use_max_tr) {
3019		ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
3020		if (ret < 0)
3021			goto out;
3022		max_tr.entries = global_trace.entries;
3023	}
 
 
 
3024
3025	if (t->init) {
3026		ret = tracer_init(t, tr);
3027		if (ret)
3028			goto out;
3029	}
3030
 
 
3031	trace_branch_enable(tr);
3032 out:
3033	mutex_unlock(&trace_types_lock);
3034
3035	return ret;
3036}
3037
3038static ssize_t
3039tracing_set_trace_write(struct file *filp, const char __user *ubuf,
3040			size_t cnt, loff_t *ppos)
3041{
 
3042	char buf[MAX_TRACER_SIZE+1];
3043	int i;
3044	size_t ret;
3045	int err;
3046
3047	ret = cnt;
3048
3049	if (cnt > MAX_TRACER_SIZE)
3050		cnt = MAX_TRACER_SIZE;
3051
3052	if (copy_from_user(&buf, ubuf, cnt))
3053		return -EFAULT;
3054
3055	buf[cnt] = 0;
3056
3057	/* strip ending whitespace. */
3058	for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
3059		buf[i] = 0;
3060
3061	err = tracing_set_tracer(buf);
3062	if (err)
3063		return err;
3064
3065	*ppos += ret;
3066
3067	return ret;
3068}
3069
3070static ssize_t
3071tracing_max_lat_read(struct file *filp, char __user *ubuf,
3072		     size_t cnt, loff_t *ppos)
3073{
3074	unsigned long *ptr = filp->private_data;
3075	char buf[64];
3076	int r;
3077
3078	r = snprintf(buf, sizeof(buf), "%ld\n",
3079		     *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
3080	if (r > sizeof(buf))
3081		r = sizeof(buf);
3082	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3083}
3084
3085static ssize_t
3086tracing_max_lat_write(struct file *filp, const char __user *ubuf,
3087		      size_t cnt, loff_t *ppos)
3088{
3089	unsigned long *ptr = filp->private_data;
3090	unsigned long val;
3091	int ret;
3092
3093	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3094	if (ret)
3095		return ret;
3096
3097	*ptr = val * 1000;
3098
3099	return cnt;
3100}
3101
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3102static int tracing_open_pipe(struct inode *inode, struct file *filp)
3103{
3104	long cpu_file = (long) inode->i_private;
3105	struct trace_iterator *iter;
3106	int ret = 0;
3107
3108	if (tracing_disabled)
3109		return -ENODEV;
 
3110
3111	mutex_lock(&trace_types_lock);
3112
3113	/* create a buffer to store the information to pass to userspace */
3114	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3115	if (!iter) {
3116		ret = -ENOMEM;
 
3117		goto out;
3118	}
3119
3120	/*
3121	 * We make a copy of the current tracer to avoid concurrent
3122	 * changes on it while we are reading.
3123	 */
3124	iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
3125	if (!iter->trace) {
3126		ret = -ENOMEM;
3127		goto fail;
3128	}
3129	if (current_trace)
3130		*iter->trace = *current_trace;
3131
3132	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
3133		ret = -ENOMEM;
3134		goto fail;
3135	}
3136
3137	/* trace pipe does not show start of buffer */
3138	cpumask_setall(iter->started);
3139
3140	if (trace_flags & TRACE_ITER_LATENCY_FMT)
3141		iter->iter_flags |= TRACE_FILE_LAT_FMT;
3142
3143	iter->cpu_file = cpu_file;
3144	iter->tr = &global_trace;
 
 
 
 
 
3145	mutex_init(&iter->mutex);
3146	filp->private_data = iter;
3147
3148	if (iter->trace->pipe_open)
3149		iter->trace->pipe_open(iter);
3150
3151	nonseekable_open(inode, filp);
 
 
3152out:
3153	mutex_unlock(&trace_types_lock);
3154	return ret;
3155
3156fail:
3157	kfree(iter->trace);
3158	kfree(iter);
 
3159	mutex_unlock(&trace_types_lock);
3160	return ret;
3161}
3162
3163static int tracing_release_pipe(struct inode *inode, struct file *file)
3164{
3165	struct trace_iterator *iter = file->private_data;
 
3166
3167	mutex_lock(&trace_types_lock);
3168
 
 
3169	if (iter->trace->pipe_close)
3170		iter->trace->pipe_close(iter);
3171
3172	mutex_unlock(&trace_types_lock);
3173
3174	free_cpumask_var(iter->started);
 
3175	mutex_destroy(&iter->mutex);
3176	kfree(iter->trace);
3177	kfree(iter);
3178
 
 
3179	return 0;
3180}
3181
3182static unsigned int
3183tracing_poll_pipe(struct file *filp, poll_table *poll_table)
3184{
3185	struct trace_iterator *iter = filp->private_data;
 
 
 
 
3186
3187	if (trace_flags & TRACE_ITER_BLOCK) {
3188		/*
3189		 * Always select as readable when in blocking mode
3190		 */
3191		return POLLIN | POLLRDNORM;
3192	} else {
3193		if (!trace_empty(iter))
3194			return POLLIN | POLLRDNORM;
3195		poll_wait(filp, &trace_wait, poll_table);
3196		if (!trace_empty(iter))
3197			return POLLIN | POLLRDNORM;
3198
3199		return 0;
3200	}
3201}
3202
3203
3204void default_wait_pipe(struct trace_iterator *iter)
3205{
3206	DEFINE_WAIT(wait);
3207
3208	prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
3209
3210	if (trace_empty(iter))
3211		schedule();
3212
3213	finish_wait(&trace_wait, &wait);
3214}
3215
3216/*
3217 * This is a make-shift waitqueue.
3218 * A tracer might use this callback on some rare cases:
3219 *
3220 *  1) the current tracer might hold the runqueue lock when it wakes up
3221 *     a reader, hence a deadlock (sched, function, and function graph tracers)
3222 *  2) the function tracers, trace all functions, we don't want
3223 *     the overhead of calling wake_up and friends
3224 *     (and tracing them too)
3225 *
3226 *     Anyway, this is really very primitive wakeup.
3227 */
3228void poll_wait_pipe(struct trace_iterator *iter)
3229{
3230	set_current_state(TASK_INTERRUPTIBLE);
3231	/* sleep for 100 msecs, and try again. */
3232	schedule_timeout(HZ / 10);
3233}
3234
3235/* Must be called with trace_types_lock mutex held. */
3236static int tracing_wait_pipe(struct file *filp)
3237{
3238	struct trace_iterator *iter = filp->private_data;
 
3239
3240	while (trace_empty(iter)) {
3241
3242		if ((filp->f_flags & O_NONBLOCK)) {
3243			return -EAGAIN;
3244		}
3245
3246		mutex_unlock(&iter->mutex);
3247
3248		iter->trace->wait_pipe(iter);
3249
3250		mutex_lock(&iter->mutex);
3251
3252		if (signal_pending(current))
3253			return -EINTR;
3254
3255		/*
3256		 * We block until we read something and tracing is disabled.
3257		 * We still block if tracing is disabled, but we have never
3258		 * read anything. This allows a user to cat this file, and
3259		 * then enable tracing. But after we have read something,
3260		 * we give an EOF when tracing is again disabled.
3261		 *
3262		 * iter->pos will be 0 if we haven't read anything.
3263		 */
3264		if (!tracer_enabled && iter->pos)
3265			break;
 
 
 
 
 
 
 
 
 
3266	}
3267
3268	return 1;
3269}
3270
3271/*
3272 * Consumer reader.
3273 */
3274static ssize_t
3275tracing_read_pipe(struct file *filp, char __user *ubuf,
3276		  size_t cnt, loff_t *ppos)
3277{
3278	struct trace_iterator *iter = filp->private_data;
3279	static struct tracer *old_tracer;
3280	ssize_t sret;
3281
3282	/* return any leftover data */
3283	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3284	if (sret != -EBUSY)
3285		return sret;
3286
3287	trace_seq_init(&iter->seq);
3288
3289	/* copy the tracer to avoid using a global lock all around */
3290	mutex_lock(&trace_types_lock);
3291	if (unlikely(old_tracer != current_trace && current_trace)) {
3292		old_tracer = current_trace;
3293		*iter->trace = *current_trace;
3294	}
3295	mutex_unlock(&trace_types_lock);
3296
3297	/*
3298	 * Avoid more than one consumer on a single file descriptor
3299	 * This is just a matter of traces coherency, the ring buffer itself
3300	 * is protected.
3301	 */
3302	mutex_lock(&iter->mutex);
 
 
 
 
 
 
 
 
3303	if (iter->trace->read) {
3304		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
3305		if (sret)
3306			goto out;
3307	}
3308
3309waitagain:
3310	sret = tracing_wait_pipe(filp);
3311	if (sret <= 0)
3312		goto out;
3313
3314	/* stop when tracing is finished */
3315	if (trace_empty(iter)) {
3316		sret = 0;
3317		goto out;
3318	}
3319
3320	if (cnt >= PAGE_SIZE)
3321		cnt = PAGE_SIZE - 1;
3322
3323	/* reset all but tr, trace, and overruns */
3324	memset(&iter->seq, 0,
3325	       sizeof(struct trace_iterator) -
3326	       offsetof(struct trace_iterator, seq));
3327	iter->pos = -1;
3328
3329	trace_event_read_lock();
3330	trace_access_lock(iter->cpu_file);
3331	while (trace_find_next_entry_inc(iter) != NULL) {
3332		enum print_line_t ret;
3333		int len = iter->seq.len;
3334
3335		ret = print_trace_line(iter);
3336		if (ret == TRACE_TYPE_PARTIAL_LINE) {
3337			/* don't print partial lines */
3338			iter->seq.len = len;
 
 
 
 
 
 
 
 
 
 
 
 
 
3339			break;
3340		}
3341		if (ret != TRACE_TYPE_NO_CONSUME)
3342			trace_consume(iter);
3343
3344		if (iter->seq.len >= cnt)
3345			break;
3346
3347		/*
3348		 * Setting the full flag means we reached the trace_seq buffer
3349		 * size and we should leave by partial output condition above.
3350		 * One of the trace_seq_* functions is not used properly.
3351		 */
3352		WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
3353			  iter->ent->type);
3354	}
3355	trace_access_unlock(iter->cpu_file);
3356	trace_event_read_unlock();
3357
3358	/* Now copy what we have to the user */
3359	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3360	if (iter->seq.readpos >= iter->seq.len)
3361		trace_seq_init(&iter->seq);
3362
3363	/*
3364	 * If there was nothing to send to user, in spite of consuming trace
3365	 * entries, go back to wait for more entries.
3366	 */
3367	if (sret == -EBUSY)
3368		goto waitagain;
3369
3370out:
3371	mutex_unlock(&iter->mutex);
3372
3373	return sret;
3374}
3375
3376static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
3377				     struct pipe_buffer *buf)
3378{
3379	__free_page(buf->page);
3380}
3381
3382static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
3383				     unsigned int idx)
3384{
3385	__free_page(spd->pages[idx]);
3386}
3387
3388static const struct pipe_buf_operations tracing_pipe_buf_ops = {
3389	.can_merge		= 0,
3390	.map			= generic_pipe_buf_map,
3391	.unmap			= generic_pipe_buf_unmap,
3392	.confirm		= generic_pipe_buf_confirm,
3393	.release		= tracing_pipe_buf_release,
3394	.steal			= generic_pipe_buf_steal,
3395	.get			= generic_pipe_buf_get,
3396};
3397
3398static size_t
3399tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
3400{
3401	size_t count;
 
3402	int ret;
3403
3404	/* Seq buffer is page-sized, exactly what we need. */
3405	for (;;) {
3406		count = iter->seq.len;
3407		ret = print_trace_line(iter);
3408		count = iter->seq.len - count;
3409		if (rem < count) {
3410			rem = 0;
3411			iter->seq.len -= count;
3412			break;
3413		}
 
 
 
 
 
 
3414		if (ret == TRACE_TYPE_PARTIAL_LINE) {
3415			iter->seq.len -= count;
 
 
 
 
 
 
 
3416			break;
3417		}
3418
3419		if (ret != TRACE_TYPE_NO_CONSUME)
3420			trace_consume(iter);
3421		rem -= count;
3422		if (!trace_find_next_entry_inc(iter))	{
3423			rem = 0;
3424			iter->ent = NULL;
3425			break;
3426		}
3427	}
3428
3429	return rem;
3430}
3431
3432static ssize_t tracing_splice_read_pipe(struct file *filp,
3433					loff_t *ppos,
3434					struct pipe_inode_info *pipe,
3435					size_t len,
3436					unsigned int flags)
3437{
3438	struct page *pages_def[PIPE_DEF_BUFFERS];
3439	struct partial_page partial_def[PIPE_DEF_BUFFERS];
3440	struct trace_iterator *iter = filp->private_data;
3441	struct splice_pipe_desc spd = {
3442		.pages		= pages_def,
3443		.partial	= partial_def,
3444		.nr_pages	= 0, /* This gets updated below. */
3445		.flags		= flags,
3446		.ops		= &tracing_pipe_buf_ops,
3447		.spd_release	= tracing_spd_release_pipe,
3448	};
3449	static struct tracer *old_tracer;
3450	ssize_t ret;
3451	size_t rem;
3452	unsigned int i;
3453
3454	if (splice_grow_spd(pipe, &spd))
3455		return -ENOMEM;
3456
3457	/* copy the tracer to avoid using a global lock all around */
3458	mutex_lock(&trace_types_lock);
3459	if (unlikely(old_tracer != current_trace && current_trace)) {
3460		old_tracer = current_trace;
3461		*iter->trace = *current_trace;
3462	}
3463	mutex_unlock(&trace_types_lock);
3464
3465	mutex_lock(&iter->mutex);
3466
3467	if (iter->trace->splice_read) {
3468		ret = iter->trace->splice_read(iter, filp,
3469					       ppos, pipe, len, flags);
3470		if (ret)
3471			goto out_err;
3472	}
3473
3474	ret = tracing_wait_pipe(filp);
3475	if (ret <= 0)
3476		goto out_err;
3477
3478	if (!iter->ent && !trace_find_next_entry_inc(iter)) {
3479		ret = -EFAULT;
3480		goto out_err;
3481	}
3482
3483	trace_event_read_lock();
3484	trace_access_lock(iter->cpu_file);
3485
3486	/* Fill as many pages as possible. */
3487	for (i = 0, rem = len; i < pipe->buffers && rem; i++) {
3488		spd.pages[i] = alloc_page(GFP_KERNEL);
3489		if (!spd.pages[i])
3490			break;
3491
3492		rem = tracing_fill_pipe_page(rem, iter);
3493
3494		/* Copy the data into the page, so we can start over. */
3495		ret = trace_seq_to_buffer(&iter->seq,
3496					  page_address(spd.pages[i]),
3497					  iter->seq.len);
3498		if (ret < 0) {
3499			__free_page(spd.pages[i]);
3500			break;
3501		}
3502		spd.partial[i].offset = 0;
3503		spd.partial[i].len = iter->seq.len;
3504
3505		trace_seq_init(&iter->seq);
3506	}
3507
3508	trace_access_unlock(iter->cpu_file);
3509	trace_event_read_unlock();
3510	mutex_unlock(&iter->mutex);
3511
3512	spd.nr_pages = i;
3513
3514	ret = splice_to_pipe(pipe, &spd);
 
 
 
3515out:
3516	splice_shrink_spd(pipe, &spd);
3517	return ret;
3518
3519out_err:
3520	mutex_unlock(&iter->mutex);
3521	goto out;
3522}
3523
3524static ssize_t
3525tracing_entries_read(struct file *filp, char __user *ubuf,
3526		     size_t cnt, loff_t *ppos)
3527{
3528	struct trace_array *tr = filp->private_data;
3529	char buf[96];
3530	int r;
 
 
 
3531
3532	mutex_lock(&trace_types_lock);
3533	if (!ring_buffer_expanded)
3534		r = sprintf(buf, "%lu (expanded: %lu)\n",
3535			    tr->entries >> 10,
3536			    trace_buf_size >> 10);
3537	else
3538		r = sprintf(buf, "%lu\n", tr->entries >> 10);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3539	mutex_unlock(&trace_types_lock);
3540
3541	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 
3542}
3543
3544static ssize_t
3545tracing_entries_write(struct file *filp, const char __user *ubuf,
3546		      size_t cnt, loff_t *ppos)
3547{
 
 
3548	unsigned long val;
3549	int ret;
3550
3551	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3552	if (ret)
3553		return ret;
3554
3555	/* must have at least 1 entry */
3556	if (!val)
3557		return -EINVAL;
3558
3559	/* value is in KB */
3560	val <<= 10;
3561
3562	ret = tracing_resize_ring_buffer(val);
3563	if (ret < 0)
3564		return ret;
3565
3566	*ppos += cnt;
3567
3568	return cnt;
3569}
3570
3571static ssize_t
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3572tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
3573			  size_t cnt, loff_t *ppos)
3574{
3575	/*
3576	 * There is no need to read what the user has written, this function
3577	 * is just to make sure that there is no error when "echo" is used
3578	 */
3579
3580	*ppos += cnt;
3581
3582	return cnt;
3583}
3584
3585static int
3586tracing_free_buffer_release(struct inode *inode, struct file *filp)
3587{
 
 
3588	/* disable tracing ? */
3589	if (trace_flags & TRACE_ITER_STOP_ON_FREE)
3590		tracing_off();
3591	/* resize the ring buffer to 0 */
3592	tracing_resize_ring_buffer(0);
3593
3594	return 0;
3595}
3596
3597static int mark_printk(const char *fmt, ...)
3598{
3599	int ret;
3600	va_list args;
3601	va_start(args, fmt);
3602	ret = trace_vprintk(0, fmt, args);
3603	va_end(args);
3604	return ret;
3605}
3606
3607static ssize_t
3608tracing_mark_write(struct file *filp, const char __user *ubuf,
3609					size_t cnt, loff_t *fpos)
3610{
3611	char *buf;
3612	size_t written;
 
 
 
 
 
 
 
 
 
 
3613
3614	if (tracing_disabled)
3615		return -EINVAL;
3616
 
 
 
3617	if (cnt > TRACE_BUF_SIZE)
3618		cnt = TRACE_BUF_SIZE;
3619
3620	buf = kmalloc(cnt + 2, GFP_KERNEL);
3621	if (buf == NULL)
3622		return -ENOMEM;
3623
3624	if (copy_from_user(buf, ubuf, cnt)) {
3625		kfree(buf);
3626		return -EFAULT;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3627	}
3628	if (buf[cnt-1] != '\n') {
3629		buf[cnt] = '\n';
3630		buf[cnt+1] = '\0';
 
3631	} else
3632		buf[cnt] = '\0';
3633
3634	written = mark_printk("%s", buf);
3635	kfree(buf);
3636	*fpos += written;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3637
3638	/* don't tell userspace we wrote more - it might confuse them */
3639	if (written > cnt)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3640		written = cnt;
3641
 
 
3642	return written;
3643}
3644
3645static int tracing_clock_show(struct seq_file *m, void *v)
3646{
 
3647	int i;
3648
3649	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
3650		seq_printf(m,
3651			"%s%s%s%s", i ? " " : "",
3652			i == trace_clock_id ? "[" : "", trace_clocks[i].name,
3653			i == trace_clock_id ? "]" : "");
3654	seq_putc(m, '\n');
3655
3656	return 0;
3657}
3658
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3659static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
3660				   size_t cnt, loff_t *fpos)
3661{
 
 
3662	char buf[64];
3663	const char *clockstr;
3664	int i;
3665
3666	if (cnt >= sizeof(buf))
3667		return -EINVAL;
3668
3669	if (copy_from_user(&buf, ubuf, cnt))
3670		return -EFAULT;
3671
3672	buf[cnt] = 0;
3673
3674	clockstr = strstrip(buf);
3675
3676	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
3677		if (strcmp(trace_clocks[i].name, clockstr) == 0)
3678			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3679	}
3680	if (i == ARRAY_SIZE(trace_clocks))
3681		return -EINVAL;
3682
3683	trace_clock_id = i;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3684
3685	mutex_lock(&trace_types_lock);
3686
3687	ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
3688	if (max_tr.buffer)
3689		ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
 
 
 
 
 
 
 
 
 
 
3690
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3691	mutex_unlock(&trace_types_lock);
 
 
3692
3693	*fpos += cnt;
 
 
 
3694
3695	return cnt;
 
 
 
 
 
 
 
 
 
 
3696}
3697
3698static int tracing_clock_open(struct inode *inode, struct file *file)
 
 
 
 
 
 
 
3699{
3700	if (tracing_disabled)
3701		return -ENODEV;
3702	return single_open(file, tracing_clock_show, NULL);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3703}
3704
3705static const struct file_operations tracing_max_lat_fops = {
 
 
 
3706	.open		= tracing_open_generic,
3707	.read		= tracing_max_lat_read,
3708	.write		= tracing_max_lat_write,
3709	.llseek		= generic_file_llseek,
3710};
3711
3712static const struct file_operations tracing_ctrl_fops = {
 
3713	.open		= tracing_open_generic,
3714	.read		= tracing_ctrl_read,
3715	.write		= tracing_ctrl_write,
3716	.llseek		= generic_file_llseek,
3717};
 
3718
3719static const struct file_operations set_tracer_fops = {
3720	.open		= tracing_open_generic,
3721	.read		= tracing_set_trace_read,
3722	.write		= tracing_set_trace_write,
3723	.llseek		= generic_file_llseek,
3724};
3725
3726static const struct file_operations tracing_pipe_fops = {
3727	.open		= tracing_open_pipe,
3728	.poll		= tracing_poll_pipe,
3729	.read		= tracing_read_pipe,
3730	.splice_read	= tracing_splice_read_pipe,
3731	.release	= tracing_release_pipe,
3732	.llseek		= no_llseek,
3733};
3734
3735static const struct file_operations tracing_entries_fops = {
3736	.open		= tracing_open_generic,
3737	.read		= tracing_entries_read,
3738	.write		= tracing_entries_write,
3739	.llseek		= generic_file_llseek,
 
 
 
 
 
 
 
 
3740};
3741
3742static const struct file_operations tracing_free_buffer_fops = {
 
3743	.write		= tracing_free_buffer_write,
3744	.release	= tracing_free_buffer_release,
3745};
3746
3747static const struct file_operations tracing_mark_fops = {
3748	.open		= tracing_open_generic,
3749	.write		= tracing_mark_write,
3750	.llseek		= generic_file_llseek,
 
 
 
 
 
 
3751};
3752
3753static const struct file_operations trace_clock_fops = {
3754	.open		= tracing_clock_open,
3755	.read		= seq_read,
3756	.llseek		= seq_lseek,
3757	.release	= single_release,
3758	.write		= tracing_clock_write,
3759};
3760
3761struct ftrace_buffer_info {
3762	struct trace_array	*tr;
3763	void			*spare;
3764	int			cpu;
3765	unsigned int		read;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3766};
3767
3768static int tracing_buffers_open(struct inode *inode, struct file *filp)
3769{
3770	int cpu = (int)(long)inode->i_private;
3771	struct ftrace_buffer_info *info;
 
3772
3773	if (tracing_disabled)
3774		return -ENODEV;
 
3775
3776	info = kzalloc(sizeof(*info), GFP_KERNEL);
3777	if (!info)
 
3778		return -ENOMEM;
 
3779
3780	info->tr	= &global_trace;
3781	info->cpu	= cpu;
3782	info->spare	= NULL;
 
 
 
 
3783	/* Force reading ring buffer for first read */
3784	info->read	= (unsigned int)-1;
3785
3786	filp->private_data = info;
3787
3788	return nonseekable_open(inode, filp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3789}
3790
3791static ssize_t
3792tracing_buffers_read(struct file *filp, char __user *ubuf,
3793		     size_t count, loff_t *ppos)
3794{
3795	struct ftrace_buffer_info *info = filp->private_data;
3796	ssize_t ret;
3797	size_t size;
 
3798
3799	if (!count)
3800		return 0;
3801
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3802	if (!info->spare)
3803		info->spare = ring_buffer_alloc_read_page(info->tr->buffer, info->cpu);
3804	if (!info->spare)
3805		return -ENOMEM;
3806
3807	/* Do we have previous read data to read? */
3808	if (info->read < PAGE_SIZE)
3809		goto read;
3810
3811	info->read = 0;
3812
3813	trace_access_lock(info->cpu);
3814	ret = ring_buffer_read_page(info->tr->buffer,
3815				    &info->spare,
3816				    count,
3817				    info->cpu, 0);
3818	trace_access_unlock(info->cpu);
3819	if (ret < 0)
 
 
 
 
 
 
 
 
 
 
 
3820		return 0;
 
3821
3822read:
 
3823	size = PAGE_SIZE - info->read;
3824	if (size > count)
3825		size = count;
3826
3827	ret = copy_to_user(ubuf, info->spare + info->read, size);
3828	if (ret == size)
3829		return -EFAULT;
 
3830	size -= ret;
3831
3832	*ppos += size;
3833	info->read += size;
3834
3835	return size;
3836}
3837
3838static int tracing_buffers_release(struct inode *inode, struct file *file)
3839{
3840	struct ftrace_buffer_info *info = file->private_data;
 
 
 
 
 
 
 
 
 
 
 
 
 
3841
3842	if (info->spare)
3843		ring_buffer_free_read_page(info->tr->buffer, info->spare);
3844	kfree(info);
 
 
 
3845
3846	return 0;
3847}
3848
3849struct buffer_ref {
3850	struct ring_buffer	*buffer;
3851	void			*page;
3852	int			ref;
 
3853};
3854
3855static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
3856				    struct pipe_buffer *buf)
3857{
3858	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3859
3860	if (--ref->ref)
3861		return;
3862
3863	ring_buffer_free_read_page(ref->buffer, ref->page);
3864	kfree(ref);
3865	buf->private = 0;
3866}
3867
3868static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
3869				 struct pipe_buffer *buf)
3870{
3871	return 1;
 
 
 
3872}
3873
3874static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
3875				struct pipe_buffer *buf)
3876{
3877	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3878
3879	ref->ref++;
 
 
 
 
3880}
3881
3882/* Pipe buffer operations for a buffer. */
3883static const struct pipe_buf_operations buffer_pipe_buf_ops = {
3884	.can_merge		= 0,
3885	.map			= generic_pipe_buf_map,
3886	.unmap			= generic_pipe_buf_unmap,
3887	.confirm		= generic_pipe_buf_confirm,
3888	.release		= buffer_pipe_buf_release,
3889	.steal			= buffer_pipe_buf_steal,
3890	.get			= buffer_pipe_buf_get,
3891};
3892
3893/*
3894 * Callback from splice_to_pipe(), if we need to release some pages
3895 * at the end of the spd in case we error'ed out in filling the pipe.
3896 */
3897static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3898{
3899	struct buffer_ref *ref =
3900		(struct buffer_ref *)spd->partial[i].private;
3901
3902	if (--ref->ref)
3903		return;
3904
3905	ring_buffer_free_read_page(ref->buffer, ref->page);
3906	kfree(ref);
3907	spd->partial[i].private = 0;
3908}
3909
3910static ssize_t
3911tracing_buffers_splice_read(struct file *file, loff_t *ppos,
3912			    struct pipe_inode_info *pipe, size_t len,
3913			    unsigned int flags)
3914{
3915	struct ftrace_buffer_info *info = file->private_data;
 
3916	struct partial_page partial_def[PIPE_DEF_BUFFERS];
3917	struct page *pages_def[PIPE_DEF_BUFFERS];
3918	struct splice_pipe_desc spd = {
3919		.pages		= pages_def,
3920		.partial	= partial_def,
3921		.flags		= flags,
3922		.ops		= &buffer_pipe_buf_ops,
3923		.spd_release	= buffer_spd_release,
3924	};
3925	struct buffer_ref *ref;
3926	int entries, size, i;
3927	size_t ret;
3928
3929	if (splice_grow_spd(pipe, &spd))
3930		return -ENOMEM;
 
 
3931
3932	if (*ppos & (PAGE_SIZE - 1)) {
3933		WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3934		ret = -EINVAL;
3935		goto out;
3936	}
3937
3938	if (len & (PAGE_SIZE - 1)) {
3939		WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3940		if (len < PAGE_SIZE) {
3941			ret = -EINVAL;
3942			goto out;
3943		}
3944		len &= PAGE_MASK;
3945	}
3946
3947	trace_access_lock(info->cpu);
3948	entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
 
 
 
 
3949
3950	for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
3951		struct page *page;
3952		int r;
3953
3954		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3955		if (!ref)
 
3956			break;
 
3957
3958		ref->ref = 1;
3959		ref->buffer = info->tr->buffer;
3960		ref->page = ring_buffer_alloc_read_page(ref->buffer, info->cpu);
3961		if (!ref->page) {
 
 
3962			kfree(ref);
3963			break;
3964		}
 
3965
3966		r = ring_buffer_read_page(ref->buffer, &ref->page,
3967					  len, info->cpu, 1);
3968		if (r < 0) {
3969			ring_buffer_free_read_page(ref->buffer, ref->page);
 
3970			kfree(ref);
3971			break;
3972		}
3973
3974		/*
3975		 * zero out any left over data, this is going to
3976		 * user land.
3977		 */
3978		size = ring_buffer_page_len(ref->page);
3979		if (size < PAGE_SIZE)
3980			memset(ref->page + size, 0, PAGE_SIZE - size);
3981
3982		page = virt_to_page(ref->page);
3983
3984		spd.pages[i] = page;
3985		spd.partial[i].len = PAGE_SIZE;
3986		spd.partial[i].offset = 0;
3987		spd.partial[i].private = (unsigned long)ref;
3988		spd.nr_pages++;
3989		*ppos += PAGE_SIZE;
3990
3991		entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
3992	}
3993
3994	trace_access_unlock(info->cpu);
3995	spd.nr_pages = i;
3996
3997	/* did we read anything? */
3998	if (!spd.nr_pages) {
3999		if (flags & SPLICE_F_NONBLOCK)
4000			ret = -EAGAIN;
4001		else
4002			ret = 0;
4003		/* TODO: block */
4004		goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4005	}
4006
4007	ret = splice_to_pipe(pipe, &spd);
4008	splice_shrink_spd(pipe, &spd);
4009out:
 
 
4010	return ret;
4011}
4012
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4013static const struct file_operations tracing_buffers_fops = {
4014	.open		= tracing_buffers_open,
4015	.read		= tracing_buffers_read,
 
4016	.release	= tracing_buffers_release,
4017	.splice_read	= tracing_buffers_splice_read,
 
4018	.llseek		= no_llseek,
4019};
4020
4021static ssize_t
4022tracing_stats_read(struct file *filp, char __user *ubuf,
4023		   size_t count, loff_t *ppos)
4024{
4025	unsigned long cpu = (unsigned long)filp->private_data;
4026	struct trace_array *tr = &global_trace;
 
 
4027	struct trace_seq *s;
4028	unsigned long cnt;
 
 
4029
4030	s = kmalloc(sizeof(*s), GFP_KERNEL);
4031	if (!s)
4032		return -ENOMEM;
4033
4034	trace_seq_init(s);
4035
4036	cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
4037	trace_seq_printf(s, "entries: %ld\n", cnt);
4038
4039	cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
4040	trace_seq_printf(s, "overrun: %ld\n", cnt);
4041
4042	cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
4043	trace_seq_printf(s, "commit overrun: %ld\n", cnt);
4044
4045	count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4046
4047	kfree(s);
4048
4049	return count;
4050}
4051
4052static const struct file_operations tracing_stats_fops = {
4053	.open		= tracing_open_generic,
4054	.read		= tracing_stats_read,
4055	.llseek		= generic_file_llseek,
 
4056};
4057
4058#ifdef CONFIG_DYNAMIC_FTRACE
4059
4060int __weak ftrace_arch_read_dyn_info(char *buf, int size)
4061{
4062	return 0;
4063}
4064
4065static ssize_t
4066tracing_read_dyn_info(struct file *filp, char __user *ubuf,
4067		  size_t cnt, loff_t *ppos)
4068{
4069	static char ftrace_dyn_info_buffer[1024];
4070	static DEFINE_MUTEX(dyn_info_mutex);
4071	unsigned long *p = filp->private_data;
4072	char *buf = ftrace_dyn_info_buffer;
4073	int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
4074	int r;
4075
4076	mutex_lock(&dyn_info_mutex);
4077	r = sprintf(buf, "%ld ", *p);
4078
4079	r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
4080	buf[r++] = '\n';
4081
4082	r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4083
4084	mutex_unlock(&dyn_info_mutex);
 
 
 
4085
4086	return r;
 
 
4087}
4088
4089static const struct file_operations tracing_dyn_info_fops = {
4090	.open		= tracing_open_generic,
4091	.read		= tracing_read_dyn_info,
4092	.llseek		= generic_file_llseek,
4093};
4094#endif
4095
4096static struct dentry *d_tracer;
 
 
 
 
 
 
 
4097
4098struct dentry *tracing_init_dentry(void)
 
 
 
4099{
4100	static int once;
 
4101
4102	if (d_tracer)
4103		return d_tracer;
4104
4105	if (!debugfs_initialized())
4106		return NULL;
4107
4108	d_tracer = debugfs_create_dir("tracing", NULL);
 
4109
4110	if (!d_tracer && !once) {
4111		once = 1;
4112		pr_warning("Could not create debugfs directory 'tracing'\n");
4113		return NULL;
4114	}
4115
4116	return d_tracer;
4117}
4118
4119static struct dentry *d_percpu;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4120
4121struct dentry *tracing_dentry_percpu(void)
 
 
4122{
4123	static int once;
4124	struct dentry *d_tracer;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4125
4126	if (d_percpu)
4127		return d_percpu;
 
 
 
 
 
4128
4129	d_tracer = tracing_init_dentry();
 
 
 
4130
4131	if (!d_tracer)
 
4132		return NULL;
4133
4134	d_percpu = debugfs_create_dir("per_cpu", d_tracer);
 
 
 
 
 
 
 
 
 
4135
4136	if (!d_percpu && !once) {
4137		once = 1;
4138		pr_warning("Could not create debugfs directory 'per_cpu'\n");
4139		return NULL;
4140	}
4141
4142	return d_percpu;
 
 
 
 
 
4143}
4144
4145static void tracing_init_debugfs_percpu(long cpu)
 
 
 
 
 
 
 
 
 
 
 
 
4146{
4147	struct dentry *d_percpu = tracing_dentry_percpu();
4148	struct dentry *d_cpu;
4149	char cpu_dir[30]; /* 30 characters should be more than enough */
4150
 
 
 
4151	snprintf(cpu_dir, 30, "cpu%ld", cpu);
4152	d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
4153	if (!d_cpu) {
4154		pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
4155		return;
4156	}
4157
4158	/* per cpu trace_pipe */
4159	trace_create_file("trace_pipe", 0444, d_cpu,
4160			(void *) cpu, &tracing_pipe_fops);
4161
4162	/* per cpu trace */
4163	trace_create_file("trace", 0644, d_cpu,
4164			(void *) cpu, &tracing_fops);
 
 
 
4165
4166	trace_create_file("trace_pipe_raw", 0444, d_cpu,
4167			(void *) cpu, &tracing_buffers_fops);
4168
4169	trace_create_file("stats", 0444, d_cpu,
4170			(void *) cpu, &tracing_stats_fops);
 
 
 
 
 
 
 
 
4171}
4172
4173#ifdef CONFIG_FTRACE_SELFTEST
4174/* Let selftest have access to static functions in this file */
4175#include "trace_selftest.c"
4176#endif
4177
4178struct trace_option_dentry {
4179	struct tracer_opt		*opt;
4180	struct tracer_flags		*flags;
4181	struct dentry			*entry;
4182};
4183
4184static ssize_t
4185trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
4186			loff_t *ppos)
4187{
4188	struct trace_option_dentry *topt = filp->private_data;
4189	char *buf;
4190
4191	if (topt->flags->val & topt->opt->bit)
4192		buf = "1\n";
4193	else
4194		buf = "0\n";
4195
4196	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4197}
4198
4199static ssize_t
4200trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
4201			 loff_t *ppos)
4202{
4203	struct trace_option_dentry *topt = filp->private_data;
4204	unsigned long val;
4205	int ret;
4206
4207	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4208	if (ret)
4209		return ret;
4210
4211	if (val != 0 && val != 1)
4212		return -EINVAL;
4213
4214	if (!!(topt->flags->val & topt->opt->bit) != val) {
4215		mutex_lock(&trace_types_lock);
4216		ret = __set_tracer_option(current_trace, topt->flags,
4217					  topt->opt, !val);
4218		mutex_unlock(&trace_types_lock);
4219		if (ret)
4220			return ret;
4221	}
4222
4223	*ppos += cnt;
4224
4225	return cnt;
4226}
4227
4228
4229static const struct file_operations trace_options_fops = {
4230	.open = tracing_open_generic,
4231	.read = trace_options_read,
4232	.write = trace_options_write,
4233	.llseek	= generic_file_llseek,
4234};
4235
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4236static ssize_t
4237trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
4238			loff_t *ppos)
4239{
4240	long index = (long)filp->private_data;
 
 
4241	char *buf;
4242
4243	if (trace_flags & (1 << index))
 
 
4244		buf = "1\n";
4245	else
4246		buf = "0\n";
4247
4248	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4249}
4250
4251static ssize_t
4252trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
4253			 loff_t *ppos)
4254{
4255	long index = (long)filp->private_data;
 
 
4256	unsigned long val;
4257	int ret;
4258
 
 
4259	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4260	if (ret)
4261		return ret;
4262
4263	if (val != 0 && val != 1)
4264		return -EINVAL;
4265	set_tracer_flags(1 << index, val);
 
 
 
 
 
 
 
 
4266
4267	*ppos += cnt;
4268
4269	return cnt;
4270}
4271
4272static const struct file_operations trace_options_core_fops = {
4273	.open = tracing_open_generic,
4274	.read = trace_options_core_read,
4275	.write = trace_options_core_write,
4276	.llseek = generic_file_llseek,
4277};
4278
4279struct dentry *trace_create_file(const char *name,
4280				 mode_t mode,
4281				 struct dentry *parent,
4282				 void *data,
4283				 const struct file_operations *fops)
4284{
4285	struct dentry *ret;
4286
4287	ret = debugfs_create_file(name, mode, parent, data, fops);
4288	if (!ret)
4289		pr_warning("Could not create debugfs '%s' entry\n", name);
4290
4291	return ret;
4292}
4293
4294
4295static struct dentry *trace_options_init_dentry(void)
4296{
4297	struct dentry *d_tracer;
4298	static struct dentry *t_options;
4299
4300	if (t_options)
4301		return t_options;
4302
4303	d_tracer = tracing_init_dentry();
4304	if (!d_tracer)
4305		return NULL;
4306
4307	t_options = debugfs_create_dir("options", d_tracer);
4308	if (!t_options) {
4309		pr_warning("Could not create debugfs directory 'options'\n");
4310		return NULL;
4311	}
4312
4313	return t_options;
4314}
4315
4316static void
4317create_trace_option_file(struct trace_option_dentry *topt,
 
4318			 struct tracer_flags *flags,
4319			 struct tracer_opt *opt)
4320{
4321	struct dentry *t_options;
4322
4323	t_options = trace_options_init_dentry();
4324	if (!t_options)
4325		return;
4326
4327	topt->flags = flags;
4328	topt->opt = opt;
 
4329
4330	topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
4331				    &trace_options_fops);
4332
4333}
4334
4335static struct trace_option_dentry *
4336create_trace_option_files(struct tracer *tracer)
4337{
4338	struct trace_option_dentry *topts;
 
4339	struct tracer_flags *flags;
4340	struct tracer_opt *opts;
4341	int cnt;
 
4342
4343	if (!tracer)
4344		return NULL;
4345
4346	flags = tracer->flags;
4347
4348	if (!flags || !flags->opts)
4349		return NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
4350
4351	opts = flags->opts;
4352
4353	for (cnt = 0; opts[cnt].name; cnt++)
4354		;
4355
4356	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
4357	if (!topts)
4358		return NULL;
4359
4360	for (cnt = 0; opts[cnt].name; cnt++)
4361		create_trace_option_file(&topts[cnt], flags,
4362					 &opts[cnt]);
4363
4364	return topts;
4365}
4366
4367static void
4368destroy_trace_option_files(struct trace_option_dentry *topts)
4369{
4370	int cnt;
4371
4372	if (!topts)
4373		return;
4374
4375	for (cnt = 0; topts[cnt].opt; cnt++) {
4376		if (topts[cnt].entry)
4377			debugfs_remove(topts[cnt].entry);
 
 
4378	}
4379
4380	kfree(topts);
 
 
 
 
 
 
 
 
 
 
 
4381}
4382
4383static struct dentry *
4384create_trace_option_core_file(const char *option, long index)
 
4385{
4386	struct dentry *t_options;
4387
4388	t_options = trace_options_init_dentry();
4389	if (!t_options)
4390		return NULL;
4391
4392	return trace_create_file(option, 0644, t_options, (void *)index,
4393				    &trace_options_core_fops);
 
4394}
4395
4396static __init void create_trace_options_dir(void)
4397{
4398	struct dentry *t_options;
 
4399	int i;
4400
4401	t_options = trace_options_init_dentry();
4402	if (!t_options)
4403		return;
4404
4405	for (i = 0; trace_options[i]; i++)
4406		create_trace_option_core_file(trace_options[i], i);
 
 
 
4407}
4408
4409static __init int tracer_init_debugfs(void)
 
 
4410{
4411	struct dentry *d_tracer;
4412	int cpu;
 
4413
4414	trace_access_lock_init();
 
4415
4416	d_tracer = tracing_init_dentry();
 
4417
4418	trace_create_file("tracing_enabled", 0644, d_tracer,
4419			&global_trace, &tracing_ctrl_fops);
 
 
 
 
 
 
4420
4421	trace_create_file("trace_options", 0644, d_tracer,
4422			NULL, &tracing_iter_fops);
 
4423
4424	trace_create_file("tracing_cpumask", 0644, d_tracer,
4425			NULL, &tracing_cpumask_fops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4426
4427	trace_create_file("trace", 0644, d_tracer,
4428			(void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
4429
4430	trace_create_file("available_tracers", 0444, d_tracer,
4431			&global_trace, &show_traces_fops);
 
 
 
 
 
 
 
 
4432
4433	trace_create_file("current_tracer", 0644, d_tracer,
4434			&global_trace, &set_tracer_fops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4435
4436#ifdef CONFIG_TRACER_MAX_TRACE
4437	trace_create_file("tracing_max_latency", 0644, d_tracer,
4438			&tracing_max_latency, &tracing_max_lat_fops);
 
 
 
 
 
 
 
 
 
 
 
4439#endif
4440
4441	trace_create_file("tracing_thresh", 0644, d_tracer,
4442			&tracing_thresh, &tracing_max_lat_fops);
4443
4444	trace_create_file("README", 0444, d_tracer,
4445			NULL, &tracing_readme_fops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4446
4447	trace_create_file("trace_pipe", 0444, d_tracer,
4448			(void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
4449
4450	trace_create_file("buffer_size_kb", 0644, d_tracer,
4451			&global_trace, &tracing_entries_fops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4452
4453	trace_create_file("free_buffer", 0644, d_tracer,
4454			&global_trace, &tracing_free_buffer_fops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4455
4456	trace_create_file("trace_marker", 0220, d_tracer,
4457			NULL, &tracing_mark_fops);
4458
4459	trace_create_file("saved_cmdlines", 0444, d_tracer,
4460			NULL, &tracing_saved_cmdlines_fops);
 
 
 
4461
4462	trace_create_file("trace_clock", 0644, d_tracer, NULL,
 
 
 
4463			  &trace_clock_fops);
4464
4465#ifdef CONFIG_DYNAMIC_FTRACE
4466	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
4467			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4468#endif
4469
4470	create_trace_options_dir();
 
4471
4472	for_each_tracing_cpu(cpu)
4473		tracing_init_debugfs_percpu(cpu);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4474
4475	return 0;
4476}
4477
4478static int trace_panic_handler(struct notifier_block *this,
4479			       unsigned long event, void *unused)
 
 
 
 
 
 
4480{
4481	if (ftrace_dump_on_oops)
4482		ftrace_dump(ftrace_dump_on_oops);
4483	return NOTIFY_OK;
 
4484}
4485
4486static struct notifier_block trace_panic_notifier = {
4487	.notifier_call  = trace_panic_handler,
4488	.next           = NULL,
4489	.priority       = 150   /* priority: INT_MAX >= x >= 0 */
4490};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4491
4492static int trace_die_handler(struct notifier_block *self,
4493			     unsigned long val,
4494			     void *data)
4495{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4496	switch (val) {
4497	case DIE_OOPS:
4498		if (ftrace_dump_on_oops)
4499			ftrace_dump(ftrace_dump_on_oops);
4500		break;
4501	default:
 
4502		break;
4503	}
 
4504	return NOTIFY_OK;
4505}
4506
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4507static struct notifier_block trace_die_notifier = {
4508	.notifier_call = trace_die_handler,
4509	.priority = 200
4510};
4511
4512/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4513 * printk is set to max of 1024, we really don't need it that big.
4514 * Nothing should be printing 1000 characters anyway.
4515 */
4516#define TRACE_MAX_PRINT		1000
4517
4518/*
4519 * Define here KERN_TRACE so that we have one place to modify
4520 * it if we decide to change what log level the ftrace dump
4521 * should be at.
4522 */
4523#define KERN_TRACE		KERN_EMERG
4524
4525void
4526trace_printk_seq(struct trace_seq *s)
4527{
4528	/* Probably should print a warning here. */
4529	if (s->len >= 1000)
4530		s->len = 1000;
 
 
 
 
 
 
 
 
4531
4532	/* should be zero ended, but we are paranoid. */
4533	s->buffer[s->len] = 0;
4534
4535	printk(KERN_TRACE "%s", s->buffer);
4536
4537	trace_seq_init(s);
4538}
4539
4540void trace_init_global_iter(struct trace_iterator *iter)
4541{
4542	iter->tr = &global_trace;
4543	iter->trace = current_trace;
4544	iter->cpu_file = TRACE_PIPE_ALL_CPU;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4545}
4546
4547static void
4548__ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
4549{
4550	static arch_spinlock_t ftrace_dump_lock =
4551		(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
4552	/* use static because iter can be a bit big for the stack */
4553	static struct trace_iterator iter;
 
 
4554	unsigned int old_userobj;
4555	static int dump_ran;
4556	unsigned long flags;
4557	int cnt = 0, cpu;
4558
4559	/* only one dump */
4560	local_irq_save(flags);
4561	arch_spin_lock(&ftrace_dump_lock);
4562	if (dump_ran)
4563		goto out;
4564
4565	dump_ran = 1;
4566
 
 
 
 
 
 
 
 
4567	tracing_off();
4568
4569	if (disable_tracing)
4570		ftrace_kill();
4571
 
4572	trace_init_global_iter(&iter);
4573
4574	for_each_tracing_cpu(cpu) {
4575		atomic_inc(&iter.tr->data[cpu]->disabled);
4576	}
4577
4578	old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
4579
4580	/* don't look at user memory in panic mode */
4581	trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4582
4583	/* Simulate the iterator */
4584	iter.tr = &global_trace;
4585	iter.trace = current_trace;
4586
4587	switch (oops_dump_mode) {
4588	case DUMP_ALL:
4589		iter.cpu_file = TRACE_PIPE_ALL_CPU;
4590		break;
4591	case DUMP_ORIG:
4592		iter.cpu_file = raw_smp_processor_id();
4593		break;
4594	case DUMP_NONE:
4595		goto out_enable;
4596	default:
4597		printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
4598		iter.cpu_file = TRACE_PIPE_ALL_CPU;
4599	}
4600
4601	printk(KERN_TRACE "Dumping ftrace buffer:\n");
4602
 
 
 
 
 
 
4603	/*
4604	 * We need to stop all tracing on all CPUS to read the
4605	 * the next buffer. This is a bit expensive, but is
4606	 * not done often. We fill all what we can read,
4607	 * and then release the locks again.
4608	 */
4609
4610	while (!trace_empty(&iter)) {
4611
4612		if (!cnt)
4613			printk(KERN_TRACE "---------------------------------\n");
4614
4615		cnt++;
4616
4617		/* reset all but tr, trace, and overruns */
4618		memset(&iter.seq, 0,
4619		       sizeof(struct trace_iterator) -
4620		       offsetof(struct trace_iterator, seq));
4621		iter.iter_flags |= TRACE_FILE_LAT_FMT;
4622		iter.pos = -1;
4623
4624		if (trace_find_next_entry_inc(&iter) != NULL) {
4625			int ret;
4626
4627			ret = print_trace_line(&iter);
4628			if (ret != TRACE_TYPE_NO_CONSUME)
4629				trace_consume(&iter);
4630		}
 
4631
4632		trace_printk_seq(&iter.seq);
4633	}
4634
4635	if (!cnt)
4636		printk(KERN_TRACE "   (ftrace buffer empty)\n");
4637	else
4638		printk(KERN_TRACE "---------------------------------\n");
4639
4640 out_enable:
4641	/* Re-enable tracing if requested */
4642	if (!disable_tracing) {
4643		trace_flags |= old_userobj;
4644
4645		for_each_tracing_cpu(cpu) {
4646			atomic_dec(&iter.tr->data[cpu]->disabled);
4647		}
4648		tracing_on();
4649	}
4650
4651 out:
4652	arch_spin_unlock(&ftrace_dump_lock);
4653	local_irq_restore(flags);
4654}
 
4655
4656/* By default: disable tracing after the dump */
4657void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
 
 
 
4658{
4659	__ftrace_dump(true, oops_dump_mode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4660}
4661
4662__init static int tracer_alloc_buffers(void)
4663{
4664	int ring_buf_size;
4665	enum ring_buffer_flags rb_flags;
4666	int i;
4667	int ret = -ENOMEM;
4668
4669
 
 
 
 
 
 
 
 
 
 
 
4670	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
4671		goto out;
4672
4673	if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
4674		goto out_free_buffer_mask;
4675
 
 
 
 
 
4676	/* To save memory, keep the ring buffer size to its minimum */
4677	if (ring_buffer_expanded)
4678		ring_buf_size = trace_buf_size;
4679	else
4680		ring_buf_size = 1;
4681
4682	rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
4683
4684	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
4685	cpumask_copy(tracing_cpumask, cpu_all_mask);
4686
4687	/* TODO: make the number of buffers hot pluggable with CPUS */
4688	global_trace.buffer = ring_buffer_alloc(ring_buf_size, rb_flags);
4689	if (!global_trace.buffer) {
4690		printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
4691		WARN_ON(1);
 
 
 
 
 
 
 
4692		goto out_free_cpumask;
4693	}
4694	global_trace.entries = ring_buffer_size(global_trace.buffer);
 
 
 
4695
 
 
4696
4697#ifdef CONFIG_TRACER_MAX_TRACE
4698	max_tr.buffer = ring_buffer_alloc(1, rb_flags);
4699	if (!max_tr.buffer) {
4700		printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
4701		WARN_ON(1);
4702		ring_buffer_free(global_trace.buffer);
4703		goto out_free_cpumask;
4704	}
4705	max_tr.entries = 1;
4706#endif
4707
4708	/* Allocate the first page for all buffers */
4709	for_each_tracing_cpu(i) {
4710		global_trace.data[i] = &per_cpu(global_trace_cpu, i);
4711		max_tr.data[i] = &per_cpu(max_tr_data, i);
 
 
 
 
4712	}
4713
4714	trace_init_cmdlines();
 
 
 
 
 
 
 
 
 
 
 
4715
4716	register_tracer(&nop_trace);
4717	current_trace = &nop_trace;
 
 
 
4718	/* All seems OK, enable tracing */
4719	tracing_disabled = 0;
4720
4721	atomic_notifier_chain_register(&panic_notifier_list,
4722				       &trace_panic_notifier);
4723
4724	register_die_notifier(&trace_die_notifier);
4725
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4726	return 0;
4727
 
 
 
 
 
 
4728out_free_cpumask:
4729	free_cpumask_var(tracing_cpumask);
4730out_free_buffer_mask:
4731	free_cpumask_var(tracing_buffer_mask);
4732out:
4733	return ret;
4734}
4735
4736__init static int clear_boot_tracer(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4737{
4738	/*
4739	 * The default tracer at boot buffer is an init section.
4740	 * This function is called in lateinit. If we did not
4741	 * find the boot tracer, then clear it out, to prevent
4742	 * later registration from accessing the buffer that is
4743	 * about to be freed.
4744	 */
4745	if (!default_bootup_tracer)
4746		return 0;
4747
4748	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
4749	       default_bootup_tracer);
4750	default_bootup_tracer = NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4751
 
 
4752	return 0;
4753}
4754
4755early_initcall(tracer_alloc_buffers);
4756fs_initcall(tracer_init_debugfs);
4757late_initcall(clear_boot_tracer);