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