1 /* 2 * event tracer 3 * 4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com> 5 * 6 * - Added format output of fields of the trace point. 7 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>. 8 * 9 */ 10 11 #define pr_fmt(fmt) fmt 12 13 #include <linux/workqueue.h> 14 #include <linux/spinlock.h> 15 #include <linux/kthread.h> 16 #include <linux/tracefs.h> 17 #include <linux/uaccess.h> 18 #include <linux/module.h> 19 #include <linux/ctype.h> 20 #include <linux/slab.h> 21 #include <linux/delay.h> 22 23 #include <asm/setup.h> 24 25 #include "trace_output.h" 26 27 #undef TRACE_SYSTEM 28 #define TRACE_SYSTEM "TRACE_SYSTEM" 29 30 DEFINE_MUTEX(event_mutex); 31 32 LIST_HEAD(ftrace_events); 33 static LIST_HEAD(ftrace_common_fields); 34 35 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO) 36 37 static struct kmem_cache *field_cachep; 38 static struct kmem_cache *file_cachep; 39 40 #define SYSTEM_FL_FREE_NAME (1 << 31) 41 42 static inline int system_refcount(struct event_subsystem *system) 43 { 44 return system->ref_count & ~SYSTEM_FL_FREE_NAME; 45 } 46 47 static int system_refcount_inc(struct event_subsystem *system) 48 { 49 return (system->ref_count++) & ~SYSTEM_FL_FREE_NAME; 50 } 51 52 static int system_refcount_dec(struct event_subsystem *system) 53 { 54 return (--system->ref_count) & ~SYSTEM_FL_FREE_NAME; 55 } 56 57 /* Double loops, do not use break, only goto's work */ 58 #define do_for_each_event_file(tr, file) \ 59 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \ 60 list_for_each_entry(file, &tr->events, list) 61 62 #define do_for_each_event_file_safe(tr, file) \ 63 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \ 64 struct ftrace_event_file *___n; \ 65 list_for_each_entry_safe(file, ___n, &tr->events, list) 66 67 #define while_for_each_event_file() \ 68 } 69 70 static struct list_head * 71 trace_get_fields(struct ftrace_event_call *event_call) 72 { 73 if (!event_call->class->get_fields) 74 return &event_call->class->fields; 75 return event_call->class->get_fields(event_call); 76 } 77 78 static struct ftrace_event_field * 79 __find_event_field(struct list_head *head, char *name) 80 { 81 struct ftrace_event_field *field; 82 83 list_for_each_entry(field, head, link) { 84 if (!strcmp(field->name, name)) 85 return field; 86 } 87 88 return NULL; 89 } 90 91 struct ftrace_event_field * 92 trace_find_event_field(struct ftrace_event_call *call, char *name) 93 { 94 struct ftrace_event_field *field; 95 struct list_head *head; 96 97 field = __find_event_field(&ftrace_common_fields, name); 98 if (field) 99 return field; 100 101 head = trace_get_fields(call); 102 return __find_event_field(head, name); 103 } 104 105 static int __trace_define_field(struct list_head *head, const char *type, 106 const char *name, int offset, int size, 107 int is_signed, int filter_type) 108 { 109 struct ftrace_event_field *field; 110 111 field = kmem_cache_alloc(field_cachep, GFP_TRACE); 112 if (!field) 113 return -ENOMEM; 114 115 field->name = name; 116 field->type = type; 117 118 if (filter_type == FILTER_OTHER) 119 field->filter_type = filter_assign_type(type); 120 else 121 field->filter_type = filter_type; 122 123 field->offset = offset; 124 field->size = size; 125 field->is_signed = is_signed; 126 127 list_add(&field->link, head); 128 129 return 0; 130 } 131 132 int trace_define_field(struct ftrace_event_call *call, const char *type, 133 const char *name, int offset, int size, int is_signed, 134 int filter_type) 135 { 136 struct list_head *head; 137 138 if (WARN_ON(!call->class)) 139 return 0; 140 141 head = trace_get_fields(call); 142 return __trace_define_field(head, type, name, offset, size, 143 is_signed, filter_type); 144 } 145 EXPORT_SYMBOL_GPL(trace_define_field); 146 147 #define __common_field(type, item) \ 148 ret = __trace_define_field(&ftrace_common_fields, #type, \ 149 "common_" #item, \ 150 offsetof(typeof(ent), item), \ 151 sizeof(ent.item), \ 152 is_signed_type(type), FILTER_OTHER); \ 153 if (ret) \ 154 return ret; 155 156 static int trace_define_common_fields(void) 157 { 158 int ret; 159 struct trace_entry ent; 160 161 __common_field(unsigned short, type); 162 __common_field(unsigned char, flags); 163 __common_field(unsigned char, preempt_count); 164 __common_field(int, pid); 165 166 return ret; 167 } 168 169 static void trace_destroy_fields(struct ftrace_event_call *call) 170 { 171 struct ftrace_event_field *field, *next; 172 struct list_head *head; 173 174 head = trace_get_fields(call); 175 list_for_each_entry_safe(field, next, head, link) { 176 list_del(&field->link); 177 kmem_cache_free(field_cachep, field); 178 } 179 } 180 181 int trace_event_raw_init(struct ftrace_event_call *call) 182 { 183 int id; 184 185 id = register_ftrace_event(&call->event); 186 if (!id) 187 return -ENODEV; 188 189 return 0; 190 } 191 EXPORT_SYMBOL_GPL(trace_event_raw_init); 192 193 void *ftrace_event_buffer_reserve(struct ftrace_event_buffer *fbuffer, 194 struct ftrace_event_file *ftrace_file, 195 unsigned long len) 196 { 197 struct ftrace_event_call *event_call = ftrace_file->event_call; 198 199 local_save_flags(fbuffer->flags); 200 fbuffer->pc = preempt_count(); 201 fbuffer->ftrace_file = ftrace_file; 202 203 fbuffer->event = 204 trace_event_buffer_lock_reserve(&fbuffer->buffer, ftrace_file, 205 event_call->event.type, len, 206 fbuffer->flags, fbuffer->pc); 207 if (!fbuffer->event) 208 return NULL; 209 210 fbuffer->entry = ring_buffer_event_data(fbuffer->event); 211 return fbuffer->entry; 212 } 213 EXPORT_SYMBOL_GPL(ftrace_event_buffer_reserve); 214 215 static DEFINE_SPINLOCK(tracepoint_iter_lock); 216 217 static void output_printk(struct ftrace_event_buffer *fbuffer) 218 { 219 struct ftrace_event_call *event_call; 220 struct trace_event *event; 221 unsigned long flags; 222 struct trace_iterator *iter = tracepoint_print_iter; 223 224 if (!iter) 225 return; 226 227 event_call = fbuffer->ftrace_file->event_call; 228 if (!event_call || !event_call->event.funcs || 229 !event_call->event.funcs->trace) 230 return; 231 232 event = &fbuffer->ftrace_file->event_call->event; 233 234 spin_lock_irqsave(&tracepoint_iter_lock, flags); 235 trace_seq_init(&iter->seq); 236 iter->ent = fbuffer->entry; 237 event_call->event.funcs->trace(iter, 0, event); 238 trace_seq_putc(&iter->seq, 0); 239 printk("%s", iter->seq.buffer); 240 241 spin_unlock_irqrestore(&tracepoint_iter_lock, flags); 242 } 243 244 void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer) 245 { 246 if (tracepoint_printk) 247 output_printk(fbuffer); 248 249 event_trigger_unlock_commit(fbuffer->ftrace_file, fbuffer->buffer, 250 fbuffer->event, fbuffer->entry, 251 fbuffer->flags, fbuffer->pc); 252 } 253 EXPORT_SYMBOL_GPL(ftrace_event_buffer_commit); 254 255 int ftrace_event_reg(struct ftrace_event_call *call, 256 enum trace_reg type, void *data) 257 { 258 struct ftrace_event_file *file = data; 259 260 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT)); 261 switch (type) { 262 case TRACE_REG_REGISTER: 263 return tracepoint_probe_register(call->tp, 264 call->class->probe, 265 file); 266 case TRACE_REG_UNREGISTER: 267 tracepoint_probe_unregister(call->tp, 268 call->class->probe, 269 file); 270 return 0; 271 272 #ifdef CONFIG_PERF_EVENTS 273 case TRACE_REG_PERF_REGISTER: 274 return tracepoint_probe_register(call->tp, 275 call->class->perf_probe, 276 call); 277 case TRACE_REG_PERF_UNREGISTER: 278 tracepoint_probe_unregister(call->tp, 279 call->class->perf_probe, 280 call); 281 return 0; 282 case TRACE_REG_PERF_OPEN: 283 case TRACE_REG_PERF_CLOSE: 284 case TRACE_REG_PERF_ADD: 285 case TRACE_REG_PERF_DEL: 286 return 0; 287 #endif 288 } 289 return 0; 290 } 291 EXPORT_SYMBOL_GPL(ftrace_event_reg); 292 293 void trace_event_enable_cmd_record(bool enable) 294 { 295 struct ftrace_event_file *file; 296 struct trace_array *tr; 297 298 mutex_lock(&event_mutex); 299 do_for_each_event_file(tr, file) { 300 301 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) 302 continue; 303 304 if (enable) { 305 tracing_start_cmdline_record(); 306 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags); 307 } else { 308 tracing_stop_cmdline_record(); 309 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags); 310 } 311 } while_for_each_event_file(); 312 mutex_unlock(&event_mutex); 313 } 314 315 static int __ftrace_event_enable_disable(struct ftrace_event_file *file, 316 int enable, int soft_disable) 317 { 318 struct ftrace_event_call *call = file->event_call; 319 int ret = 0; 320 int disable; 321 322 switch (enable) { 323 case 0: 324 /* 325 * When soft_disable is set and enable is cleared, the sm_ref 326 * reference counter is decremented. If it reaches 0, we want 327 * to clear the SOFT_DISABLED flag but leave the event in the 328 * state that it was. That is, if the event was enabled and 329 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED 330 * is set we do not want the event to be enabled before we 331 * clear the bit. 332 * 333 * When soft_disable is not set but the SOFT_MODE flag is, 334 * we do nothing. Do not disable the tracepoint, otherwise 335 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work. 336 */ 337 if (soft_disable) { 338 if (atomic_dec_return(&file->sm_ref) > 0) 339 break; 340 disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED; 341 clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags); 342 } else 343 disable = !(file->flags & FTRACE_EVENT_FL_SOFT_MODE); 344 345 if (disable && (file->flags & FTRACE_EVENT_FL_ENABLED)) { 346 clear_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags); 347 if (file->flags & FTRACE_EVENT_FL_RECORDED_CMD) { 348 tracing_stop_cmdline_record(); 349 clear_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags); 350 } 351 call->class->reg(call, TRACE_REG_UNREGISTER, file); 352 } 353 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */ 354 if (file->flags & FTRACE_EVENT_FL_SOFT_MODE) 355 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags); 356 else 357 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags); 358 break; 359 case 1: 360 /* 361 * When soft_disable is set and enable is set, we want to 362 * register the tracepoint for the event, but leave the event 363 * as is. That means, if the event was already enabled, we do 364 * nothing (but set SOFT_MODE). If the event is disabled, we 365 * set SOFT_DISABLED before enabling the event tracepoint, so 366 * it still seems to be disabled. 367 */ 368 if (!soft_disable) 369 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags); 370 else { 371 if (atomic_inc_return(&file->sm_ref) > 1) 372 break; 373 set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags); 374 } 375 376 if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) { 377 378 /* Keep the event disabled, when going to SOFT_MODE. */ 379 if (soft_disable) 380 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags); 381 382 if (trace_flags & TRACE_ITER_RECORD_CMD) { 383 tracing_start_cmdline_record(); 384 set_bit(FTRACE_EVENT_FL_RECORDED_CMD_BIT, &file->flags); 385 } 386 ret = call->class->reg(call, TRACE_REG_REGISTER, file); 387 if (ret) { 388 tracing_stop_cmdline_record(); 389 pr_info("event trace: Could not enable event " 390 "%s\n", ftrace_event_name(call)); 391 break; 392 } 393 set_bit(FTRACE_EVENT_FL_ENABLED_BIT, &file->flags); 394 395 /* WAS_ENABLED gets set but never cleared. */ 396 call->flags |= TRACE_EVENT_FL_WAS_ENABLED; 397 } 398 break; 399 } 400 401 return ret; 402 } 403 404 int trace_event_enable_disable(struct ftrace_event_file *file, 405 int enable, int soft_disable) 406 { 407 return __ftrace_event_enable_disable(file, enable, soft_disable); 408 } 409 410 static int ftrace_event_enable_disable(struct ftrace_event_file *file, 411 int enable) 412 { 413 return __ftrace_event_enable_disable(file, enable, 0); 414 } 415 416 static void ftrace_clear_events(struct trace_array *tr) 417 { 418 struct ftrace_event_file *file; 419 420 mutex_lock(&event_mutex); 421 list_for_each_entry(file, &tr->events, list) { 422 ftrace_event_enable_disable(file, 0); 423 } 424 mutex_unlock(&event_mutex); 425 } 426 427 static void __put_system(struct event_subsystem *system) 428 { 429 struct event_filter *filter = system->filter; 430 431 WARN_ON_ONCE(system_refcount(system) == 0); 432 if (system_refcount_dec(system)) 433 return; 434 435 list_del(&system->list); 436 437 if (filter) { 438 kfree(filter->filter_string); 439 kfree(filter); 440 } 441 if (system->ref_count & SYSTEM_FL_FREE_NAME) 442 kfree(system->name); 443 kfree(system); 444 } 445 446 static void __get_system(struct event_subsystem *system) 447 { 448 WARN_ON_ONCE(system_refcount(system) == 0); 449 system_refcount_inc(system); 450 } 451 452 static void __get_system_dir(struct ftrace_subsystem_dir *dir) 453 { 454 WARN_ON_ONCE(dir->ref_count == 0); 455 dir->ref_count++; 456 __get_system(dir->subsystem); 457 } 458 459 static void __put_system_dir(struct ftrace_subsystem_dir *dir) 460 { 461 WARN_ON_ONCE(dir->ref_count == 0); 462 /* If the subsystem is about to be freed, the dir must be too */ 463 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1); 464 465 __put_system(dir->subsystem); 466 if (!--dir->ref_count) 467 kfree(dir); 468 } 469 470 static void put_system(struct ftrace_subsystem_dir *dir) 471 { 472 mutex_lock(&event_mutex); 473 __put_system_dir(dir); 474 mutex_unlock(&event_mutex); 475 } 476 477 static void remove_subsystem(struct ftrace_subsystem_dir *dir) 478 { 479 if (!dir) 480 return; 481 482 if (!--dir->nr_events) { 483 tracefs_remove_recursive(dir->entry); 484 list_del(&dir->list); 485 __put_system_dir(dir); 486 } 487 } 488 489 static void remove_event_file_dir(struct ftrace_event_file *file) 490 { 491 struct dentry *dir = file->dir; 492 struct dentry *child; 493 494 if (dir) { 495 spin_lock(&dir->d_lock); /* probably unneeded */ 496 list_for_each_entry(child, &dir->d_subdirs, d_child) { 497 if (child->d_inode) /* probably unneeded */ 498 child->d_inode->i_private = NULL; 499 } 500 spin_unlock(&dir->d_lock); 501 502 tracefs_remove_recursive(dir); 503 } 504 505 list_del(&file->list); 506 remove_subsystem(file->system); 507 free_event_filter(file->filter); 508 kmem_cache_free(file_cachep, file); 509 } 510 511 /* 512 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events. 513 */ 514 static int 515 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match, 516 const char *sub, const char *event, int set) 517 { 518 struct ftrace_event_file *file; 519 struct ftrace_event_call *call; 520 const char *name; 521 int ret = -EINVAL; 522 523 list_for_each_entry(file, &tr->events, list) { 524 525 call = file->event_call; 526 name = ftrace_event_name(call); 527 528 if (!name || !call->class || !call->class->reg) 529 continue; 530 531 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) 532 continue; 533 534 if (match && 535 strcmp(match, name) != 0 && 536 strcmp(match, call->class->system) != 0) 537 continue; 538 539 if (sub && strcmp(sub, call->class->system) != 0) 540 continue; 541 542 if (event && strcmp(event, name) != 0) 543 continue; 544 545 ftrace_event_enable_disable(file, set); 546 547 ret = 0; 548 } 549 550 return ret; 551 } 552 553 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match, 554 const char *sub, const char *event, int set) 555 { 556 int ret; 557 558 mutex_lock(&event_mutex); 559 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set); 560 mutex_unlock(&event_mutex); 561 562 return ret; 563 } 564 565 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set) 566 { 567 char *event = NULL, *sub = NULL, *match; 568 569 /* 570 * The buf format can be <subsystem>:<event-name> 571 * *:<event-name> means any event by that name. 572 * :<event-name> is the same. 573 * 574 * <subsystem>:* means all events in that subsystem 575 * <subsystem>: means the same. 576 * 577 * <name> (no ':') means all events in a subsystem with 578 * the name <name> or any event that matches <name> 579 */ 580 581 match = strsep(&buf, ":"); 582 if (buf) { 583 sub = match; 584 event = buf; 585 match = NULL; 586 587 if (!strlen(sub) || strcmp(sub, "*") == 0) 588 sub = NULL; 589 if (!strlen(event) || strcmp(event, "*") == 0) 590 event = NULL; 591 } 592 593 return __ftrace_set_clr_event(tr, match, sub, event, set); 594 } 595 596 /** 597 * trace_set_clr_event - enable or disable an event 598 * @system: system name to match (NULL for any system) 599 * @event: event name to match (NULL for all events, within system) 600 * @set: 1 to enable, 0 to disable 601 * 602 * This is a way for other parts of the kernel to enable or disable 603 * event recording. 604 * 605 * Returns 0 on success, -EINVAL if the parameters do not match any 606 * registered events. 607 */ 608 int trace_set_clr_event(const char *system, const char *event, int set) 609 { 610 struct trace_array *tr = top_trace_array(); 611 612 if (!tr) 613 return -ENODEV; 614 615 return __ftrace_set_clr_event(tr, NULL, system, event, set); 616 } 617 EXPORT_SYMBOL_GPL(trace_set_clr_event); 618 619 /* 128 should be much more than enough */ 620 #define EVENT_BUF_SIZE 127 621 622 static ssize_t 623 ftrace_event_write(struct file *file, const char __user *ubuf, 624 size_t cnt, loff_t *ppos) 625 { 626 struct trace_parser parser; 627 struct seq_file *m = file->private_data; 628 struct trace_array *tr = m->private; 629 ssize_t read, ret; 630 631 if (!cnt) 632 return 0; 633 634 ret = tracing_update_buffers(); 635 if (ret < 0) 636 return ret; 637 638 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1)) 639 return -ENOMEM; 640 641 read = trace_get_user(&parser, ubuf, cnt, ppos); 642 643 if (read >= 0 && trace_parser_loaded((&parser))) { 644 int set = 1; 645 646 if (*parser.buffer == '!') 647 set = 0; 648 649 parser.buffer[parser.idx] = 0; 650 651 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set); 652 if (ret) 653 goto out_put; 654 } 655 656 ret = read; 657 658 out_put: 659 trace_parser_put(&parser); 660 661 return ret; 662 } 663 664 static void * 665 t_next(struct seq_file *m, void *v, loff_t *pos) 666 { 667 struct ftrace_event_file *file = v; 668 struct ftrace_event_call *call; 669 struct trace_array *tr = m->private; 670 671 (*pos)++; 672 673 list_for_each_entry_continue(file, &tr->events, list) { 674 call = file->event_call; 675 /* 676 * The ftrace subsystem is for showing formats only. 677 * They can not be enabled or disabled via the event files. 678 */ 679 if (call->class && call->class->reg) 680 return file; 681 } 682 683 return NULL; 684 } 685 686 static void *t_start(struct seq_file *m, loff_t *pos) 687 { 688 struct ftrace_event_file *file; 689 struct trace_array *tr = m->private; 690 loff_t l; 691 692 mutex_lock(&event_mutex); 693 694 file = list_entry(&tr->events, struct ftrace_event_file, list); 695 for (l = 0; l <= *pos; ) { 696 file = t_next(m, file, &l); 697 if (!file) 698 break; 699 } 700 return file; 701 } 702 703 static void * 704 s_next(struct seq_file *m, void *v, loff_t *pos) 705 { 706 struct ftrace_event_file *file = v; 707 struct trace_array *tr = m->private; 708 709 (*pos)++; 710 711 list_for_each_entry_continue(file, &tr->events, list) { 712 if (file->flags & FTRACE_EVENT_FL_ENABLED) 713 return file; 714 } 715 716 return NULL; 717 } 718 719 static void *s_start(struct seq_file *m, loff_t *pos) 720 { 721 struct ftrace_event_file *file; 722 struct trace_array *tr = m->private; 723 loff_t l; 724 725 mutex_lock(&event_mutex); 726 727 file = list_entry(&tr->events, struct ftrace_event_file, list); 728 for (l = 0; l <= *pos; ) { 729 file = s_next(m, file, &l); 730 if (!file) 731 break; 732 } 733 return file; 734 } 735 736 static int t_show(struct seq_file *m, void *v) 737 { 738 struct ftrace_event_file *file = v; 739 struct ftrace_event_call *call = file->event_call; 740 741 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) 742 seq_printf(m, "%s:", call->class->system); 743 seq_printf(m, "%s\n", ftrace_event_name(call)); 744 745 return 0; 746 } 747 748 static void t_stop(struct seq_file *m, void *p) 749 { 750 mutex_unlock(&event_mutex); 751 } 752 753 static ssize_t 754 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 755 loff_t *ppos) 756 { 757 struct ftrace_event_file *file; 758 unsigned long flags; 759 char buf[4] = "0"; 760 761 mutex_lock(&event_mutex); 762 file = event_file_data(filp); 763 if (likely(file)) 764 flags = file->flags; 765 mutex_unlock(&event_mutex); 766 767 if (!file) 768 return -ENODEV; 769 770 if (flags & FTRACE_EVENT_FL_ENABLED && 771 !(flags & FTRACE_EVENT_FL_SOFT_DISABLED)) 772 strcpy(buf, "1"); 773 774 if (flags & FTRACE_EVENT_FL_SOFT_DISABLED || 775 flags & FTRACE_EVENT_FL_SOFT_MODE) 776 strcat(buf, "*"); 777 778 strcat(buf, "\n"); 779 780 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf)); 781 } 782 783 static ssize_t 784 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, 785 loff_t *ppos) 786 { 787 struct ftrace_event_file *file; 788 unsigned long val; 789 int ret; 790 791 ret = kstrtoul_from_user(ubuf, cnt, 10, &val); 792 if (ret) 793 return ret; 794 795 ret = tracing_update_buffers(); 796 if (ret < 0) 797 return ret; 798 799 switch (val) { 800 case 0: 801 case 1: 802 ret = -ENODEV; 803 mutex_lock(&event_mutex); 804 file = event_file_data(filp); 805 if (likely(file)) 806 ret = ftrace_event_enable_disable(file, val); 807 mutex_unlock(&event_mutex); 808 break; 809 810 default: 811 return -EINVAL; 812 } 813 814 *ppos += cnt; 815 816 return ret ? ret : cnt; 817 } 818 819 static ssize_t 820 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 821 loff_t *ppos) 822 { 823 const char set_to_char[4] = { '?', '0', '1', 'X' }; 824 struct ftrace_subsystem_dir *dir = filp->private_data; 825 struct event_subsystem *system = dir->subsystem; 826 struct ftrace_event_call *call; 827 struct ftrace_event_file *file; 828 struct trace_array *tr = dir->tr; 829 char buf[2]; 830 int set = 0; 831 int ret; 832 833 mutex_lock(&event_mutex); 834 list_for_each_entry(file, &tr->events, list) { 835 call = file->event_call; 836 if (!ftrace_event_name(call) || !call->class || !call->class->reg) 837 continue; 838 839 if (system && strcmp(call->class->system, system->name) != 0) 840 continue; 841 842 /* 843 * We need to find out if all the events are set 844 * or if all events or cleared, or if we have 845 * a mixture. 846 */ 847 set |= (1 << !!(file->flags & FTRACE_EVENT_FL_ENABLED)); 848 849 /* 850 * If we have a mixture, no need to look further. 851 */ 852 if (set == 3) 853 break; 854 } 855 mutex_unlock(&event_mutex); 856 857 buf[0] = set_to_char[set]; 858 buf[1] = '\n'; 859 860 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); 861 862 return ret; 863 } 864 865 static ssize_t 866 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, 867 loff_t *ppos) 868 { 869 struct ftrace_subsystem_dir *dir = filp->private_data; 870 struct event_subsystem *system = dir->subsystem; 871 const char *name = NULL; 872 unsigned long val; 873 ssize_t ret; 874 875 ret = kstrtoul_from_user(ubuf, cnt, 10, &val); 876 if (ret) 877 return ret; 878 879 ret = tracing_update_buffers(); 880 if (ret < 0) 881 return ret; 882 883 if (val != 0 && val != 1) 884 return -EINVAL; 885 886 /* 887 * Opening of "enable" adds a ref count to system, 888 * so the name is safe to use. 889 */ 890 if (system) 891 name = system->name; 892 893 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val); 894 if (ret) 895 goto out; 896 897 ret = cnt; 898 899 out: 900 *ppos += cnt; 901 902 return ret; 903 } 904 905 enum { 906 FORMAT_HEADER = 1, 907 FORMAT_FIELD_SEPERATOR = 2, 908 FORMAT_PRINTFMT = 3, 909 }; 910 911 static void *f_next(struct seq_file *m, void *v, loff_t *pos) 912 { 913 struct ftrace_event_call *call = event_file_data(m->private); 914 struct list_head *common_head = &ftrace_common_fields; 915 struct list_head *head = trace_get_fields(call); 916 struct list_head *node = v; 917 918 (*pos)++; 919 920 switch ((unsigned long)v) { 921 case FORMAT_HEADER: 922 node = common_head; 923 break; 924 925 case FORMAT_FIELD_SEPERATOR: 926 node = head; 927 break; 928 929 case FORMAT_PRINTFMT: 930 /* all done */ 931 return NULL; 932 } 933 934 node = node->prev; 935 if (node == common_head) 936 return (void *)FORMAT_FIELD_SEPERATOR; 937 else if (node == head) 938 return (void *)FORMAT_PRINTFMT; 939 else 940 return node; 941 } 942 943 static int f_show(struct seq_file *m, void *v) 944 { 945 struct ftrace_event_call *call = event_file_data(m->private); 946 struct ftrace_event_field *field; 947 const char *array_descriptor; 948 949 switch ((unsigned long)v) { 950 case FORMAT_HEADER: 951 seq_printf(m, "name: %s\n", ftrace_event_name(call)); 952 seq_printf(m, "ID: %d\n", call->event.type); 953 seq_puts(m, "format:\n"); 954 return 0; 955 956 case FORMAT_FIELD_SEPERATOR: 957 seq_putc(m, '\n'); 958 return 0; 959 960 case FORMAT_PRINTFMT: 961 seq_printf(m, "\nprint fmt: %s\n", 962 call->print_fmt); 963 return 0; 964 } 965 966 field = list_entry(v, struct ftrace_event_field, link); 967 /* 968 * Smartly shows the array type(except dynamic array). 969 * Normal: 970 * field:TYPE VAR 971 * If TYPE := TYPE[LEN], it is shown: 972 * field:TYPE VAR[LEN] 973 */ 974 array_descriptor = strchr(field->type, '['); 975 976 if (!strncmp(field->type, "__data_loc", 10)) 977 array_descriptor = NULL; 978 979 if (!array_descriptor) 980 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n", 981 field->type, field->name, field->offset, 982 field->size, !!field->is_signed); 983 else 984 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n", 985 (int)(array_descriptor - field->type), 986 field->type, field->name, 987 array_descriptor, field->offset, 988 field->size, !!field->is_signed); 989 990 return 0; 991 } 992 993 static void *f_start(struct seq_file *m, loff_t *pos) 994 { 995 void *p = (void *)FORMAT_HEADER; 996 loff_t l = 0; 997 998 /* ->stop() is called even if ->start() fails */ 999 mutex_lock(&event_mutex); 1000 if (!event_file_data(m->private)) 1001 return ERR_PTR(-ENODEV); 1002 1003 while (l < *pos && p) 1004 p = f_next(m, p, &l); 1005 1006 return p; 1007 } 1008 1009 static void f_stop(struct seq_file *m, void *p) 1010 { 1011 mutex_unlock(&event_mutex); 1012 } 1013 1014 static const struct seq_operations trace_format_seq_ops = { 1015 .start = f_start, 1016 .next = f_next, 1017 .stop = f_stop, 1018 .show = f_show, 1019 }; 1020 1021 static int trace_format_open(struct inode *inode, struct file *file) 1022 { 1023 struct seq_file *m; 1024 int ret; 1025 1026 ret = seq_open(file, &trace_format_seq_ops); 1027 if (ret < 0) 1028 return ret; 1029 1030 m = file->private_data; 1031 m->private = file; 1032 1033 return 0; 1034 } 1035 1036 static ssize_t 1037 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) 1038 { 1039 int id = (long)event_file_data(filp); 1040 char buf[32]; 1041 int len; 1042 1043 if (*ppos) 1044 return 0; 1045 1046 if (unlikely(!id)) 1047 return -ENODEV; 1048 1049 len = sprintf(buf, "%d\n", id); 1050 1051 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len); 1052 } 1053 1054 static ssize_t 1055 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt, 1056 loff_t *ppos) 1057 { 1058 struct ftrace_event_file *file; 1059 struct trace_seq *s; 1060 int r = -ENODEV; 1061 1062 if (*ppos) 1063 return 0; 1064 1065 s = kmalloc(sizeof(*s), GFP_KERNEL); 1066 1067 if (!s) 1068 return -ENOMEM; 1069 1070 trace_seq_init(s); 1071 1072 mutex_lock(&event_mutex); 1073 file = event_file_data(filp); 1074 if (file) 1075 print_event_filter(file, s); 1076 mutex_unlock(&event_mutex); 1077 1078 if (file) 1079 r = simple_read_from_buffer(ubuf, cnt, ppos, 1080 s->buffer, trace_seq_used(s)); 1081 1082 kfree(s); 1083 1084 return r; 1085 } 1086 1087 static ssize_t 1088 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, 1089 loff_t *ppos) 1090 { 1091 struct ftrace_event_file *file; 1092 char *buf; 1093 int err = -ENODEV; 1094 1095 if (cnt >= PAGE_SIZE) 1096 return -EINVAL; 1097 1098 buf = (char *)__get_free_page(GFP_TEMPORARY); 1099 if (!buf) 1100 return -ENOMEM; 1101 1102 if (copy_from_user(buf, ubuf, cnt)) { 1103 free_page((unsigned long) buf); 1104 return -EFAULT; 1105 } 1106 buf[cnt] = '\0'; 1107 1108 mutex_lock(&event_mutex); 1109 file = event_file_data(filp); 1110 if (file) 1111 err = apply_event_filter(file, buf); 1112 mutex_unlock(&event_mutex); 1113 1114 free_page((unsigned long) buf); 1115 if (err < 0) 1116 return err; 1117 1118 *ppos += cnt; 1119 1120 return cnt; 1121 } 1122 1123 static LIST_HEAD(event_subsystems); 1124 1125 static int subsystem_open(struct inode *inode, struct file *filp) 1126 { 1127 struct event_subsystem *system = NULL; 1128 struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */ 1129 struct trace_array *tr; 1130 int ret; 1131 1132 if (tracing_is_disabled()) 1133 return -ENODEV; 1134 1135 /* Make sure the system still exists */ 1136 mutex_lock(&trace_types_lock); 1137 mutex_lock(&event_mutex); 1138 list_for_each_entry(tr, &ftrace_trace_arrays, list) { 1139 list_for_each_entry(dir, &tr->systems, list) { 1140 if (dir == inode->i_private) { 1141 /* Don't open systems with no events */ 1142 if (dir->nr_events) { 1143 __get_system_dir(dir); 1144 system = dir->subsystem; 1145 } 1146 goto exit_loop; 1147 } 1148 } 1149 } 1150 exit_loop: 1151 mutex_unlock(&event_mutex); 1152 mutex_unlock(&trace_types_lock); 1153 1154 if (!system) 1155 return -ENODEV; 1156 1157 /* Some versions of gcc think dir can be uninitialized here */ 1158 WARN_ON(!dir); 1159 1160 /* Still need to increment the ref count of the system */ 1161 if (trace_array_get(tr) < 0) { 1162 put_system(dir); 1163 return -ENODEV; 1164 } 1165 1166 ret = tracing_open_generic(inode, filp); 1167 if (ret < 0) { 1168 trace_array_put(tr); 1169 put_system(dir); 1170 } 1171 1172 return ret; 1173 } 1174 1175 static int system_tr_open(struct inode *inode, struct file *filp) 1176 { 1177 struct ftrace_subsystem_dir *dir; 1178 struct trace_array *tr = inode->i_private; 1179 int ret; 1180 1181 if (tracing_is_disabled()) 1182 return -ENODEV; 1183 1184 if (trace_array_get(tr) < 0) 1185 return -ENODEV; 1186 1187 /* Make a temporary dir that has no system but points to tr */ 1188 dir = kzalloc(sizeof(*dir), GFP_KERNEL); 1189 if (!dir) { 1190 trace_array_put(tr); 1191 return -ENOMEM; 1192 } 1193 1194 dir->tr = tr; 1195 1196 ret = tracing_open_generic(inode, filp); 1197 if (ret < 0) { 1198 trace_array_put(tr); 1199 kfree(dir); 1200 return ret; 1201 } 1202 1203 filp->private_data = dir; 1204 1205 return 0; 1206 } 1207 1208 static int subsystem_release(struct inode *inode, struct file *file) 1209 { 1210 struct ftrace_subsystem_dir *dir = file->private_data; 1211 1212 trace_array_put(dir->tr); 1213 1214 /* 1215 * If dir->subsystem is NULL, then this is a temporary 1216 * descriptor that was made for a trace_array to enable 1217 * all subsystems. 1218 */ 1219 if (dir->subsystem) 1220 put_system(dir); 1221 else 1222 kfree(dir); 1223 1224 return 0; 1225 } 1226 1227 static ssize_t 1228 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt, 1229 loff_t *ppos) 1230 { 1231 struct ftrace_subsystem_dir *dir = filp->private_data; 1232 struct event_subsystem *system = dir->subsystem; 1233 struct trace_seq *s; 1234 int r; 1235 1236 if (*ppos) 1237 return 0; 1238 1239 s = kmalloc(sizeof(*s), GFP_KERNEL); 1240 if (!s) 1241 return -ENOMEM; 1242 1243 trace_seq_init(s); 1244 1245 print_subsystem_event_filter(system, s); 1246 r = simple_read_from_buffer(ubuf, cnt, ppos, 1247 s->buffer, trace_seq_used(s)); 1248 1249 kfree(s); 1250 1251 return r; 1252 } 1253 1254 static ssize_t 1255 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, 1256 loff_t *ppos) 1257 { 1258 struct ftrace_subsystem_dir *dir = filp->private_data; 1259 char *buf; 1260 int err; 1261 1262 if (cnt >= PAGE_SIZE) 1263 return -EINVAL; 1264 1265 buf = (char *)__get_free_page(GFP_TEMPORARY); 1266 if (!buf) 1267 return -ENOMEM; 1268 1269 if (copy_from_user(buf, ubuf, cnt)) { 1270 free_page((unsigned long) buf); 1271 return -EFAULT; 1272 } 1273 buf[cnt] = '\0'; 1274 1275 err = apply_subsystem_event_filter(dir, buf); 1276 free_page((unsigned long) buf); 1277 if (err < 0) 1278 return err; 1279 1280 *ppos += cnt; 1281 1282 return cnt; 1283 } 1284 1285 static ssize_t 1286 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) 1287 { 1288 int (*func)(struct trace_seq *s) = filp->private_data; 1289 struct trace_seq *s; 1290 int r; 1291 1292 if (*ppos) 1293 return 0; 1294 1295 s = kmalloc(sizeof(*s), GFP_KERNEL); 1296 if (!s) 1297 return -ENOMEM; 1298 1299 trace_seq_init(s); 1300 1301 func(s); 1302 r = simple_read_from_buffer(ubuf, cnt, ppos, 1303 s->buffer, trace_seq_used(s)); 1304 1305 kfree(s); 1306 1307 return r; 1308 } 1309 1310 static int ftrace_event_avail_open(struct inode *inode, struct file *file); 1311 static int ftrace_event_set_open(struct inode *inode, struct file *file); 1312 static int ftrace_event_release(struct inode *inode, struct file *file); 1313 1314 static const struct seq_operations show_event_seq_ops = { 1315 .start = t_start, 1316 .next = t_next, 1317 .show = t_show, 1318 .stop = t_stop, 1319 }; 1320 1321 static const struct seq_operations show_set_event_seq_ops = { 1322 .start = s_start, 1323 .next = s_next, 1324 .show = t_show, 1325 .stop = t_stop, 1326 }; 1327 1328 static const struct file_operations ftrace_avail_fops = { 1329 .open = ftrace_event_avail_open, 1330 .read = seq_read, 1331 .llseek = seq_lseek, 1332 .release = seq_release, 1333 }; 1334 1335 static const struct file_operations ftrace_set_event_fops = { 1336 .open = ftrace_event_set_open, 1337 .read = seq_read, 1338 .write = ftrace_event_write, 1339 .llseek = seq_lseek, 1340 .release = ftrace_event_release, 1341 }; 1342 1343 static const struct file_operations ftrace_enable_fops = { 1344 .open = tracing_open_generic, 1345 .read = event_enable_read, 1346 .write = event_enable_write, 1347 .llseek = default_llseek, 1348 }; 1349 1350 static const struct file_operations ftrace_event_format_fops = { 1351 .open = trace_format_open, 1352 .read = seq_read, 1353 .llseek = seq_lseek, 1354 .release = seq_release, 1355 }; 1356 1357 static const struct file_operations ftrace_event_id_fops = { 1358 .read = event_id_read, 1359 .llseek = default_llseek, 1360 }; 1361 1362 static const struct file_operations ftrace_event_filter_fops = { 1363 .open = tracing_open_generic, 1364 .read = event_filter_read, 1365 .write = event_filter_write, 1366 .llseek = default_llseek, 1367 }; 1368 1369 static const struct file_operations ftrace_subsystem_filter_fops = { 1370 .open = subsystem_open, 1371 .read = subsystem_filter_read, 1372 .write = subsystem_filter_write, 1373 .llseek = default_llseek, 1374 .release = subsystem_release, 1375 }; 1376 1377 static const struct file_operations ftrace_system_enable_fops = { 1378 .open = subsystem_open, 1379 .read = system_enable_read, 1380 .write = system_enable_write, 1381 .llseek = default_llseek, 1382 .release = subsystem_release, 1383 }; 1384 1385 static const struct file_operations ftrace_tr_enable_fops = { 1386 .open = system_tr_open, 1387 .read = system_enable_read, 1388 .write = system_enable_write, 1389 .llseek = default_llseek, 1390 .release = subsystem_release, 1391 }; 1392 1393 static const struct file_operations ftrace_show_header_fops = { 1394 .open = tracing_open_generic, 1395 .read = show_header, 1396 .llseek = default_llseek, 1397 }; 1398 1399 static int 1400 ftrace_event_open(struct inode *inode, struct file *file, 1401 const struct seq_operations *seq_ops) 1402 { 1403 struct seq_file *m; 1404 int ret; 1405 1406 ret = seq_open(file, seq_ops); 1407 if (ret < 0) 1408 return ret; 1409 m = file->private_data; 1410 /* copy tr over to seq ops */ 1411 m->private = inode->i_private; 1412 1413 return ret; 1414 } 1415 1416 static int ftrace_event_release(struct inode *inode, struct file *file) 1417 { 1418 struct trace_array *tr = inode->i_private; 1419 1420 trace_array_put(tr); 1421 1422 return seq_release(inode, file); 1423 } 1424 1425 static int 1426 ftrace_event_avail_open(struct inode *inode, struct file *file) 1427 { 1428 const struct seq_operations *seq_ops = &show_event_seq_ops; 1429 1430 return ftrace_event_open(inode, file, seq_ops); 1431 } 1432 1433 static int 1434 ftrace_event_set_open(struct inode *inode, struct file *file) 1435 { 1436 const struct seq_operations *seq_ops = &show_set_event_seq_ops; 1437 struct trace_array *tr = inode->i_private; 1438 int ret; 1439 1440 if (trace_array_get(tr) < 0) 1441 return -ENODEV; 1442 1443 if ((file->f_mode & FMODE_WRITE) && 1444 (file->f_flags & O_TRUNC)) 1445 ftrace_clear_events(tr); 1446 1447 ret = ftrace_event_open(inode, file, seq_ops); 1448 if (ret < 0) 1449 trace_array_put(tr); 1450 return ret; 1451 } 1452 1453 static struct event_subsystem * 1454 create_new_subsystem(const char *name) 1455 { 1456 struct event_subsystem *system; 1457 1458 /* need to create new entry */ 1459 system = kmalloc(sizeof(*system), GFP_KERNEL); 1460 if (!system) 1461 return NULL; 1462 1463 system->ref_count = 1; 1464 1465 /* Only allocate if dynamic (kprobes and modules) */ 1466 if (!core_kernel_data((unsigned long)name)) { 1467 system->ref_count |= SYSTEM_FL_FREE_NAME; 1468 system->name = kstrdup(name, GFP_KERNEL); 1469 if (!system->name) 1470 goto out_free; 1471 } else 1472 system->name = name; 1473 1474 system->filter = NULL; 1475 1476 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL); 1477 if (!system->filter) 1478 goto out_free; 1479 1480 list_add(&system->list, &event_subsystems); 1481 1482 return system; 1483 1484 out_free: 1485 if (system->ref_count & SYSTEM_FL_FREE_NAME) 1486 kfree(system->name); 1487 kfree(system); 1488 return NULL; 1489 } 1490 1491 static struct dentry * 1492 event_subsystem_dir(struct trace_array *tr, const char *name, 1493 struct ftrace_event_file *file, struct dentry *parent) 1494 { 1495 struct ftrace_subsystem_dir *dir; 1496 struct event_subsystem *system; 1497 struct dentry *entry; 1498 1499 /* First see if we did not already create this dir */ 1500 list_for_each_entry(dir, &tr->systems, list) { 1501 system = dir->subsystem; 1502 if (strcmp(system->name, name) == 0) { 1503 dir->nr_events++; 1504 file->system = dir; 1505 return dir->entry; 1506 } 1507 } 1508 1509 /* Now see if the system itself exists. */ 1510 list_for_each_entry(system, &event_subsystems, list) { 1511 if (strcmp(system->name, name) == 0) 1512 break; 1513 } 1514 /* Reset system variable when not found */ 1515 if (&system->list == &event_subsystems) 1516 system = NULL; 1517 1518 dir = kmalloc(sizeof(*dir), GFP_KERNEL); 1519 if (!dir) 1520 goto out_fail; 1521 1522 if (!system) { 1523 system = create_new_subsystem(name); 1524 if (!system) 1525 goto out_free; 1526 } else 1527 __get_system(system); 1528 1529 dir->entry = tracefs_create_dir(name, parent); 1530 if (!dir->entry) { 1531 pr_warn("Failed to create system directory %s\n", name); 1532 __put_system(system); 1533 goto out_free; 1534 } 1535 1536 dir->tr = tr; 1537 dir->ref_count = 1; 1538 dir->nr_events = 1; 1539 dir->subsystem = system; 1540 file->system = dir; 1541 1542 entry = tracefs_create_file("filter", 0644, dir->entry, dir, 1543 &ftrace_subsystem_filter_fops); 1544 if (!entry) { 1545 kfree(system->filter); 1546 system->filter = NULL; 1547 pr_warn("Could not create tracefs '%s/filter' entry\n", name); 1548 } 1549 1550 trace_create_file("enable", 0644, dir->entry, dir, 1551 &ftrace_system_enable_fops); 1552 1553 list_add(&dir->list, &tr->systems); 1554 1555 return dir->entry; 1556 1557 out_free: 1558 kfree(dir); 1559 out_fail: 1560 /* Only print this message if failed on memory allocation */ 1561 if (!dir || !system) 1562 pr_warn("No memory to create event subsystem %s\n", name); 1563 return NULL; 1564 } 1565 1566 static int 1567 event_create_dir(struct dentry *parent, struct ftrace_event_file *file) 1568 { 1569 struct ftrace_event_call *call = file->event_call; 1570 struct trace_array *tr = file->tr; 1571 struct list_head *head; 1572 struct dentry *d_events; 1573 const char *name; 1574 int ret; 1575 1576 /* 1577 * If the trace point header did not define TRACE_SYSTEM 1578 * then the system would be called "TRACE_SYSTEM". 1579 */ 1580 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) { 1581 d_events = event_subsystem_dir(tr, call->class->system, file, parent); 1582 if (!d_events) 1583 return -ENOMEM; 1584 } else 1585 d_events = parent; 1586 1587 name = ftrace_event_name(call); 1588 file->dir = tracefs_create_dir(name, d_events); 1589 if (!file->dir) { 1590 pr_warn("Could not create tracefs '%s' directory\n", name); 1591 return -1; 1592 } 1593 1594 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) 1595 trace_create_file("enable", 0644, file->dir, file, 1596 &ftrace_enable_fops); 1597 1598 #ifdef CONFIG_PERF_EVENTS 1599 if (call->event.type && call->class->reg) 1600 trace_create_file("id", 0444, file->dir, 1601 (void *)(long)call->event.type, 1602 &ftrace_event_id_fops); 1603 #endif 1604 1605 /* 1606 * Other events may have the same class. Only update 1607 * the fields if they are not already defined. 1608 */ 1609 head = trace_get_fields(call); 1610 if (list_empty(head)) { 1611 ret = call->class->define_fields(call); 1612 if (ret < 0) { 1613 pr_warn("Could not initialize trace point events/%s\n", 1614 name); 1615 return -1; 1616 } 1617 } 1618 trace_create_file("filter", 0644, file->dir, file, 1619 &ftrace_event_filter_fops); 1620 1621 trace_create_file("trigger", 0644, file->dir, file, 1622 &event_trigger_fops); 1623 1624 trace_create_file("format", 0444, file->dir, call, 1625 &ftrace_event_format_fops); 1626 1627 return 0; 1628 } 1629 1630 static void remove_event_from_tracers(struct ftrace_event_call *call) 1631 { 1632 struct ftrace_event_file *file; 1633 struct trace_array *tr; 1634 1635 do_for_each_event_file_safe(tr, file) { 1636 if (file->event_call != call) 1637 continue; 1638 1639 remove_event_file_dir(file); 1640 /* 1641 * The do_for_each_event_file_safe() is 1642 * a double loop. After finding the call for this 1643 * trace_array, we use break to jump to the next 1644 * trace_array. 1645 */ 1646 break; 1647 } while_for_each_event_file(); 1648 } 1649 1650 static void event_remove(struct ftrace_event_call *call) 1651 { 1652 struct trace_array *tr; 1653 struct ftrace_event_file *file; 1654 1655 do_for_each_event_file(tr, file) { 1656 if (file->event_call != call) 1657 continue; 1658 ftrace_event_enable_disable(file, 0); 1659 /* 1660 * The do_for_each_event_file() is 1661 * a double loop. After finding the call for this 1662 * trace_array, we use break to jump to the next 1663 * trace_array. 1664 */ 1665 break; 1666 } while_for_each_event_file(); 1667 1668 if (call->event.funcs) 1669 __unregister_ftrace_event(&call->event); 1670 remove_event_from_tracers(call); 1671 list_del(&call->list); 1672 } 1673 1674 static int event_init(struct ftrace_event_call *call) 1675 { 1676 int ret = 0; 1677 const char *name; 1678 1679 name = ftrace_event_name(call); 1680 if (WARN_ON(!name)) 1681 return -EINVAL; 1682 1683 if (call->class->raw_init) { 1684 ret = call->class->raw_init(call); 1685 if (ret < 0 && ret != -ENOSYS) 1686 pr_warn("Could not initialize trace events/%s\n", name); 1687 } 1688 1689 return ret; 1690 } 1691 1692 static int 1693 __register_event(struct ftrace_event_call *call, struct module *mod) 1694 { 1695 int ret; 1696 1697 ret = event_init(call); 1698 if (ret < 0) 1699 return ret; 1700 1701 list_add(&call->list, &ftrace_events); 1702 call->mod = mod; 1703 1704 return 0; 1705 } 1706 1707 static char *enum_replace(char *ptr, struct trace_enum_map *map, int len) 1708 { 1709 int rlen; 1710 int elen; 1711 1712 /* Find the length of the enum value as a string */ 1713 elen = snprintf(ptr, 0, "%ld", map->enum_value); 1714 /* Make sure there's enough room to replace the string with the value */ 1715 if (len < elen) 1716 return NULL; 1717 1718 snprintf(ptr, elen + 1, "%ld", map->enum_value); 1719 1720 /* Get the rest of the string of ptr */ 1721 rlen = strlen(ptr + len); 1722 memmove(ptr + elen, ptr + len, rlen); 1723 /* Make sure we end the new string */ 1724 ptr[elen + rlen] = 0; 1725 1726 return ptr + elen; 1727 } 1728 1729 static void update_event_printk(struct ftrace_event_call *call, 1730 struct trace_enum_map *map) 1731 { 1732 char *ptr; 1733 int quote = 0; 1734 int len = strlen(map->enum_string); 1735 1736 for (ptr = call->print_fmt; *ptr; ptr++) { 1737 if (*ptr == '\\') { 1738 ptr++; 1739 /* paranoid */ 1740 if (!*ptr) 1741 break; 1742 continue; 1743 } 1744 if (*ptr == '"') { 1745 quote ^= 1; 1746 continue; 1747 } 1748 if (quote) 1749 continue; 1750 if (isdigit(*ptr)) { 1751 /* skip numbers */ 1752 do { 1753 ptr++; 1754 /* Check for alpha chars like ULL */ 1755 } while (isalnum(*ptr)); 1756 /* 1757 * A number must have some kind of delimiter after 1758 * it, and we can ignore that too. 1759 */ 1760 continue; 1761 } 1762 if (isalpha(*ptr) || *ptr == '_') { 1763 if (strncmp(map->enum_string, ptr, len) == 0 && 1764 !isalnum(ptr[len]) && ptr[len] != '_') { 1765 ptr = enum_replace(ptr, map, len); 1766 /* Hmm, enum string smaller than value */ 1767 if (WARN_ON_ONCE(!ptr)) 1768 return; 1769 /* 1770 * No need to decrement here, as enum_replace() 1771 * returns the pointer to the character passed 1772 * the enum, and two enums can not be placed 1773 * back to back without something in between. 1774 * We can skip that something in between. 1775 */ 1776 continue; 1777 } 1778 skip_more: 1779 do { 1780 ptr++; 1781 } while (isalnum(*ptr) || *ptr == '_'); 1782 /* 1783 * If what comes after this variable is a '.' or 1784 * '->' then we can continue to ignore that string. 1785 */ 1786 if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) { 1787 ptr += *ptr == '.' ? 1 : 2; 1788 goto skip_more; 1789 } 1790 /* 1791 * Once again, we can skip the delimiter that came 1792 * after the string. 1793 */ 1794 continue; 1795 } 1796 } 1797 } 1798 1799 void trace_event_enum_update(struct trace_enum_map **map, int len) 1800 { 1801 struct ftrace_event_call *call, *p; 1802 const char *last_system = NULL; 1803 int last_i; 1804 int i; 1805 1806 down_write(&trace_event_sem); 1807 list_for_each_entry_safe(call, p, &ftrace_events, list) { 1808 /* events are usually grouped together with systems */ 1809 if (!last_system || call->class->system != last_system) { 1810 last_i = 0; 1811 last_system = call->class->system; 1812 } 1813 1814 for (i = last_i; i < len; i++) { 1815 if (call->class->system == map[i]->system) { 1816 /* Save the first system if need be */ 1817 if (!last_i) 1818 last_i = i; 1819 update_event_printk(call, map[i]); 1820 } 1821 } 1822 } 1823 up_write(&trace_event_sem); 1824 } 1825 1826 static struct ftrace_event_file * 1827 trace_create_new_event(struct ftrace_event_call *call, 1828 struct trace_array *tr) 1829 { 1830 struct ftrace_event_file *file; 1831 1832 file = kmem_cache_alloc(file_cachep, GFP_TRACE); 1833 if (!file) 1834 return NULL; 1835 1836 file->event_call = call; 1837 file->tr = tr; 1838 atomic_set(&file->sm_ref, 0); 1839 atomic_set(&file->tm_ref, 0); 1840 INIT_LIST_HEAD(&file->triggers); 1841 list_add(&file->list, &tr->events); 1842 1843 return file; 1844 } 1845 1846 /* Add an event to a trace directory */ 1847 static int 1848 __trace_add_new_event(struct ftrace_event_call *call, struct trace_array *tr) 1849 { 1850 struct ftrace_event_file *file; 1851 1852 file = trace_create_new_event(call, tr); 1853 if (!file) 1854 return -ENOMEM; 1855 1856 return event_create_dir(tr->event_dir, file); 1857 } 1858 1859 /* 1860 * Just create a decriptor for early init. A descriptor is required 1861 * for enabling events at boot. We want to enable events before 1862 * the filesystem is initialized. 1863 */ 1864 static __init int 1865 __trace_early_add_new_event(struct ftrace_event_call *call, 1866 struct trace_array *tr) 1867 { 1868 struct ftrace_event_file *file; 1869 1870 file = trace_create_new_event(call, tr); 1871 if (!file) 1872 return -ENOMEM; 1873 1874 return 0; 1875 } 1876 1877 struct ftrace_module_file_ops; 1878 static void __add_event_to_tracers(struct ftrace_event_call *call); 1879 1880 /* Add an additional event_call dynamically */ 1881 int trace_add_event_call(struct ftrace_event_call *call) 1882 { 1883 int ret; 1884 mutex_lock(&trace_types_lock); 1885 mutex_lock(&event_mutex); 1886 1887 ret = __register_event(call, NULL); 1888 if (ret >= 0) 1889 __add_event_to_tracers(call); 1890 1891 mutex_unlock(&event_mutex); 1892 mutex_unlock(&trace_types_lock); 1893 return ret; 1894 } 1895 1896 /* 1897 * Must be called under locking of trace_types_lock, event_mutex and 1898 * trace_event_sem. 1899 */ 1900 static void __trace_remove_event_call(struct ftrace_event_call *call) 1901 { 1902 event_remove(call); 1903 trace_destroy_fields(call); 1904 free_event_filter(call->filter); 1905 call->filter = NULL; 1906 } 1907 1908 static int probe_remove_event_call(struct ftrace_event_call *call) 1909 { 1910 struct trace_array *tr; 1911 struct ftrace_event_file *file; 1912 1913 #ifdef CONFIG_PERF_EVENTS 1914 if (call->perf_refcount) 1915 return -EBUSY; 1916 #endif 1917 do_for_each_event_file(tr, file) { 1918 if (file->event_call != call) 1919 continue; 1920 /* 1921 * We can't rely on ftrace_event_enable_disable(enable => 0) 1922 * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress 1923 * TRACE_REG_UNREGISTER. 1924 */ 1925 if (file->flags & FTRACE_EVENT_FL_ENABLED) 1926 return -EBUSY; 1927 /* 1928 * The do_for_each_event_file_safe() is 1929 * a double loop. After finding the call for this 1930 * trace_array, we use break to jump to the next 1931 * trace_array. 1932 */ 1933 break; 1934 } while_for_each_event_file(); 1935 1936 __trace_remove_event_call(call); 1937 1938 return 0; 1939 } 1940 1941 /* Remove an event_call */ 1942 int trace_remove_event_call(struct ftrace_event_call *call) 1943 { 1944 int ret; 1945 1946 mutex_lock(&trace_types_lock); 1947 mutex_lock(&event_mutex); 1948 down_write(&trace_event_sem); 1949 ret = probe_remove_event_call(call); 1950 up_write(&trace_event_sem); 1951 mutex_unlock(&event_mutex); 1952 mutex_unlock(&trace_types_lock); 1953 1954 return ret; 1955 } 1956 1957 #define for_each_event(event, start, end) \ 1958 for (event = start; \ 1959 (unsigned long)event < (unsigned long)end; \ 1960 event++) 1961 1962 #ifdef CONFIG_MODULES 1963 1964 static void trace_module_add_events(struct module *mod) 1965 { 1966 struct ftrace_event_call **call, **start, **end; 1967 1968 if (!mod->num_trace_events) 1969 return; 1970 1971 /* Don't add infrastructure for mods without tracepoints */ 1972 if (trace_module_has_bad_taint(mod)) { 1973 pr_err("%s: module has bad taint, not creating trace events\n", 1974 mod->name); 1975 return; 1976 } 1977 1978 start = mod->trace_events; 1979 end = mod->trace_events + mod->num_trace_events; 1980 1981 for_each_event(call, start, end) { 1982 __register_event(*call, mod); 1983 __add_event_to_tracers(*call); 1984 } 1985 } 1986 1987 static void trace_module_remove_events(struct module *mod) 1988 { 1989 struct ftrace_event_call *call, *p; 1990 bool clear_trace = false; 1991 1992 down_write(&trace_event_sem); 1993 list_for_each_entry_safe(call, p, &ftrace_events, list) { 1994 if (call->mod == mod) { 1995 if (call->flags & TRACE_EVENT_FL_WAS_ENABLED) 1996 clear_trace = true; 1997 __trace_remove_event_call(call); 1998 } 1999 } 2000 up_write(&trace_event_sem); 2001 2002 /* 2003 * It is safest to reset the ring buffer if the module being unloaded 2004 * registered any events that were used. The only worry is if 2005 * a new module gets loaded, and takes on the same id as the events 2006 * of this module. When printing out the buffer, traced events left 2007 * over from this module may be passed to the new module events and 2008 * unexpected results may occur. 2009 */ 2010 if (clear_trace) 2011 tracing_reset_all_online_cpus(); 2012 } 2013 2014 static int trace_module_notify(struct notifier_block *self, 2015 unsigned long val, void *data) 2016 { 2017 struct module *mod = data; 2018 2019 mutex_lock(&trace_types_lock); 2020 mutex_lock(&event_mutex); 2021 switch (val) { 2022 case MODULE_STATE_COMING: 2023 trace_module_add_events(mod); 2024 break; 2025 case MODULE_STATE_GOING: 2026 trace_module_remove_events(mod); 2027 break; 2028 } 2029 mutex_unlock(&event_mutex); 2030 mutex_unlock(&trace_types_lock); 2031 2032 return 0; 2033 } 2034 2035 static struct notifier_block trace_module_nb = { 2036 .notifier_call = trace_module_notify, 2037 .priority = 1, /* higher than trace.c module notify */ 2038 }; 2039 #endif /* CONFIG_MODULES */ 2040 2041 /* Create a new event directory structure for a trace directory. */ 2042 static void 2043 __trace_add_event_dirs(struct trace_array *tr) 2044 { 2045 struct ftrace_event_call *call; 2046 int ret; 2047 2048 list_for_each_entry(call, &ftrace_events, list) { 2049 ret = __trace_add_new_event(call, tr); 2050 if (ret < 0) 2051 pr_warn("Could not create directory for event %s\n", 2052 ftrace_event_name(call)); 2053 } 2054 } 2055 2056 struct ftrace_event_file * 2057 find_event_file(struct trace_array *tr, const char *system, const char *event) 2058 { 2059 struct ftrace_event_file *file; 2060 struct ftrace_event_call *call; 2061 const char *name; 2062 2063 list_for_each_entry(file, &tr->events, list) { 2064 2065 call = file->event_call; 2066 name = ftrace_event_name(call); 2067 2068 if (!name || !call->class || !call->class->reg) 2069 continue; 2070 2071 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) 2072 continue; 2073 2074 if (strcmp(event, name) == 0 && 2075 strcmp(system, call->class->system) == 0) 2076 return file; 2077 } 2078 return NULL; 2079 } 2080 2081 #ifdef CONFIG_DYNAMIC_FTRACE 2082 2083 /* Avoid typos */ 2084 #define ENABLE_EVENT_STR "enable_event" 2085 #define DISABLE_EVENT_STR "disable_event" 2086 2087 struct event_probe_data { 2088 struct ftrace_event_file *file; 2089 unsigned long count; 2090 int ref; 2091 bool enable; 2092 }; 2093 2094 static void 2095 event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data) 2096 { 2097 struct event_probe_data **pdata = (struct event_probe_data **)_data; 2098 struct event_probe_data *data = *pdata; 2099 2100 if (!data) 2101 return; 2102 2103 if (data->enable) 2104 clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags); 2105 else 2106 set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &data->file->flags); 2107 } 2108 2109 static void 2110 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, void **_data) 2111 { 2112 struct event_probe_data **pdata = (struct event_probe_data **)_data; 2113 struct event_probe_data *data = *pdata; 2114 2115 if (!data) 2116 return; 2117 2118 if (!data->count) 2119 return; 2120 2121 /* Skip if the event is in a state we want to switch to */ 2122 if (data->enable == !(data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED)) 2123 return; 2124 2125 if (data->count != -1) 2126 (data->count)--; 2127 2128 event_enable_probe(ip, parent_ip, _data); 2129 } 2130 2131 static int 2132 event_enable_print(struct seq_file *m, unsigned long ip, 2133 struct ftrace_probe_ops *ops, void *_data) 2134 { 2135 struct event_probe_data *data = _data; 2136 2137 seq_printf(m, "%ps:", (void *)ip); 2138 2139 seq_printf(m, "%s:%s:%s", 2140 data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR, 2141 data->file->event_call->class->system, 2142 ftrace_event_name(data->file->event_call)); 2143 2144 if (data->count == -1) 2145 seq_puts(m, ":unlimited\n"); 2146 else 2147 seq_printf(m, ":count=%ld\n", data->count); 2148 2149 return 0; 2150 } 2151 2152 static int 2153 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip, 2154 void **_data) 2155 { 2156 struct event_probe_data **pdata = (struct event_probe_data **)_data; 2157 struct event_probe_data *data = *pdata; 2158 2159 data->ref++; 2160 return 0; 2161 } 2162 2163 static void 2164 event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip, 2165 void **_data) 2166 { 2167 struct event_probe_data **pdata = (struct event_probe_data **)_data; 2168 struct event_probe_data *data = *pdata; 2169 2170 if (WARN_ON_ONCE(data->ref <= 0)) 2171 return; 2172 2173 data->ref--; 2174 if (!data->ref) { 2175 /* Remove the SOFT_MODE flag */ 2176 __ftrace_event_enable_disable(data->file, 0, 1); 2177 module_put(data->file->event_call->mod); 2178 kfree(data); 2179 } 2180 *pdata = NULL; 2181 } 2182 2183 static struct ftrace_probe_ops event_enable_probe_ops = { 2184 .func = event_enable_probe, 2185 .print = event_enable_print, 2186 .init = event_enable_init, 2187 .free = event_enable_free, 2188 }; 2189 2190 static struct ftrace_probe_ops event_enable_count_probe_ops = { 2191 .func = event_enable_count_probe, 2192 .print = event_enable_print, 2193 .init = event_enable_init, 2194 .free = event_enable_free, 2195 }; 2196 2197 static struct ftrace_probe_ops event_disable_probe_ops = { 2198 .func = event_enable_probe, 2199 .print = event_enable_print, 2200 .init = event_enable_init, 2201 .free = event_enable_free, 2202 }; 2203 2204 static struct ftrace_probe_ops event_disable_count_probe_ops = { 2205 .func = event_enable_count_probe, 2206 .print = event_enable_print, 2207 .init = event_enable_init, 2208 .free = event_enable_free, 2209 }; 2210 2211 static int 2212 event_enable_func(struct ftrace_hash *hash, 2213 char *glob, char *cmd, char *param, int enabled) 2214 { 2215 struct trace_array *tr = top_trace_array(); 2216 struct ftrace_event_file *file; 2217 struct ftrace_probe_ops *ops; 2218 struct event_probe_data *data; 2219 const char *system; 2220 const char *event; 2221 char *number; 2222 bool enable; 2223 int ret; 2224 2225 if (!tr) 2226 return -ENODEV; 2227 2228 /* hash funcs only work with set_ftrace_filter */ 2229 if (!enabled || !param) 2230 return -EINVAL; 2231 2232 system = strsep(¶m, ":"); 2233 if (!param) 2234 return -EINVAL; 2235 2236 event = strsep(¶m, ":"); 2237 2238 mutex_lock(&event_mutex); 2239 2240 ret = -EINVAL; 2241 file = find_event_file(tr, system, event); 2242 if (!file) 2243 goto out; 2244 2245 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0; 2246 2247 if (enable) 2248 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops; 2249 else 2250 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops; 2251 2252 if (glob[0] == '!') { 2253 unregister_ftrace_function_probe_func(glob+1, ops); 2254 ret = 0; 2255 goto out; 2256 } 2257 2258 ret = -ENOMEM; 2259 data = kzalloc(sizeof(*data), GFP_KERNEL); 2260 if (!data) 2261 goto out; 2262 2263 data->enable = enable; 2264 data->count = -1; 2265 data->file = file; 2266 2267 if (!param) 2268 goto out_reg; 2269 2270 number = strsep(¶m, ":"); 2271 2272 ret = -EINVAL; 2273 if (!strlen(number)) 2274 goto out_free; 2275 2276 /* 2277 * We use the callback data field (which is a pointer) 2278 * as our counter. 2279 */ 2280 ret = kstrtoul(number, 0, &data->count); 2281 if (ret) 2282 goto out_free; 2283 2284 out_reg: 2285 /* Don't let event modules unload while probe registered */ 2286 ret = try_module_get(file->event_call->mod); 2287 if (!ret) { 2288 ret = -EBUSY; 2289 goto out_free; 2290 } 2291 2292 ret = __ftrace_event_enable_disable(file, 1, 1); 2293 if (ret < 0) 2294 goto out_put; 2295 ret = register_ftrace_function_probe(glob, ops, data); 2296 /* 2297 * The above returns on success the # of functions enabled, 2298 * but if it didn't find any functions it returns zero. 2299 * Consider no functions a failure too. 2300 */ 2301 if (!ret) { 2302 ret = -ENOENT; 2303 goto out_disable; 2304 } else if (ret < 0) 2305 goto out_disable; 2306 /* Just return zero, not the number of enabled functions */ 2307 ret = 0; 2308 out: 2309 mutex_unlock(&event_mutex); 2310 return ret; 2311 2312 out_disable: 2313 __ftrace_event_enable_disable(file, 0, 1); 2314 out_put: 2315 module_put(file->event_call->mod); 2316 out_free: 2317 kfree(data); 2318 goto out; 2319 } 2320 2321 static struct ftrace_func_command event_enable_cmd = { 2322 .name = ENABLE_EVENT_STR, 2323 .func = event_enable_func, 2324 }; 2325 2326 static struct ftrace_func_command event_disable_cmd = { 2327 .name = DISABLE_EVENT_STR, 2328 .func = event_enable_func, 2329 }; 2330 2331 static __init int register_event_cmds(void) 2332 { 2333 int ret; 2334 2335 ret = register_ftrace_command(&event_enable_cmd); 2336 if (WARN_ON(ret < 0)) 2337 return ret; 2338 ret = register_ftrace_command(&event_disable_cmd); 2339 if (WARN_ON(ret < 0)) 2340 unregister_ftrace_command(&event_enable_cmd); 2341 return ret; 2342 } 2343 #else 2344 static inline int register_event_cmds(void) { return 0; } 2345 #endif /* CONFIG_DYNAMIC_FTRACE */ 2346 2347 /* 2348 * The top level array has already had its ftrace_event_file 2349 * descriptors created in order to allow for early events to 2350 * be recorded. This function is called after the tracefs has been 2351 * initialized, and we now have to create the files associated 2352 * to the events. 2353 */ 2354 static __init void 2355 __trace_early_add_event_dirs(struct trace_array *tr) 2356 { 2357 struct ftrace_event_file *file; 2358 int ret; 2359 2360 2361 list_for_each_entry(file, &tr->events, list) { 2362 ret = event_create_dir(tr->event_dir, file); 2363 if (ret < 0) 2364 pr_warn("Could not create directory for event %s\n", 2365 ftrace_event_name(file->event_call)); 2366 } 2367 } 2368 2369 /* 2370 * For early boot up, the top trace array requires to have 2371 * a list of events that can be enabled. This must be done before 2372 * the filesystem is set up in order to allow events to be traced 2373 * early. 2374 */ 2375 static __init void 2376 __trace_early_add_events(struct trace_array *tr) 2377 { 2378 struct ftrace_event_call *call; 2379 int ret; 2380 2381 list_for_each_entry(call, &ftrace_events, list) { 2382 /* Early boot up should not have any modules loaded */ 2383 if (WARN_ON_ONCE(call->mod)) 2384 continue; 2385 2386 ret = __trace_early_add_new_event(call, tr); 2387 if (ret < 0) 2388 pr_warn("Could not create early event %s\n", 2389 ftrace_event_name(call)); 2390 } 2391 } 2392 2393 /* Remove the event directory structure for a trace directory. */ 2394 static void 2395 __trace_remove_event_dirs(struct trace_array *tr) 2396 { 2397 struct ftrace_event_file *file, *next; 2398 2399 list_for_each_entry_safe(file, next, &tr->events, list) 2400 remove_event_file_dir(file); 2401 } 2402 2403 static void __add_event_to_tracers(struct ftrace_event_call *call) 2404 { 2405 struct trace_array *tr; 2406 2407 list_for_each_entry(tr, &ftrace_trace_arrays, list) 2408 __trace_add_new_event(call, tr); 2409 } 2410 2411 extern struct ftrace_event_call *__start_ftrace_events[]; 2412 extern struct ftrace_event_call *__stop_ftrace_events[]; 2413 2414 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata; 2415 2416 static __init int setup_trace_event(char *str) 2417 { 2418 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE); 2419 ring_buffer_expanded = true; 2420 tracing_selftest_disabled = true; 2421 2422 return 1; 2423 } 2424 __setup("trace_event=", setup_trace_event); 2425 2426 /* Expects to have event_mutex held when called */ 2427 static int 2428 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) 2429 { 2430 struct dentry *d_events; 2431 struct dentry *entry; 2432 2433 entry = tracefs_create_file("set_event", 0644, parent, 2434 tr, &ftrace_set_event_fops); 2435 if (!entry) { 2436 pr_warn("Could not create tracefs 'set_event' entry\n"); 2437 return -ENOMEM; 2438 } 2439 2440 d_events = tracefs_create_dir("events", parent); 2441 if (!d_events) { 2442 pr_warn("Could not create tracefs 'events' directory\n"); 2443 return -ENOMEM; 2444 } 2445 2446 /* ring buffer internal formats */ 2447 trace_create_file("header_page", 0444, d_events, 2448 ring_buffer_print_page_header, 2449 &ftrace_show_header_fops); 2450 2451 trace_create_file("header_event", 0444, d_events, 2452 ring_buffer_print_entry_header, 2453 &ftrace_show_header_fops); 2454 2455 trace_create_file("enable", 0644, d_events, 2456 tr, &ftrace_tr_enable_fops); 2457 2458 tr->event_dir = d_events; 2459 2460 return 0; 2461 } 2462 2463 /** 2464 * event_trace_add_tracer - add a instance of a trace_array to events 2465 * @parent: The parent dentry to place the files/directories for events in 2466 * @tr: The trace array associated with these events 2467 * 2468 * When a new instance is created, it needs to set up its events 2469 * directory, as well as other files associated with events. It also 2470 * creates the event hierachry in the @parent/events directory. 2471 * 2472 * Returns 0 on success. 2473 */ 2474 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr) 2475 { 2476 int ret; 2477 2478 mutex_lock(&event_mutex); 2479 2480 ret = create_event_toplevel_files(parent, tr); 2481 if (ret) 2482 goto out_unlock; 2483 2484 down_write(&trace_event_sem); 2485 __trace_add_event_dirs(tr); 2486 up_write(&trace_event_sem); 2487 2488 out_unlock: 2489 mutex_unlock(&event_mutex); 2490 2491 return ret; 2492 } 2493 2494 /* 2495 * The top trace array already had its file descriptors created. 2496 * Now the files themselves need to be created. 2497 */ 2498 static __init int 2499 early_event_add_tracer(struct dentry *parent, struct trace_array *tr) 2500 { 2501 int ret; 2502 2503 mutex_lock(&event_mutex); 2504 2505 ret = create_event_toplevel_files(parent, tr); 2506 if (ret) 2507 goto out_unlock; 2508 2509 down_write(&trace_event_sem); 2510 __trace_early_add_event_dirs(tr); 2511 up_write(&trace_event_sem); 2512 2513 out_unlock: 2514 mutex_unlock(&event_mutex); 2515 2516 return ret; 2517 } 2518 2519 int event_trace_del_tracer(struct trace_array *tr) 2520 { 2521 mutex_lock(&event_mutex); 2522 2523 /* Disable any event triggers and associated soft-disabled events */ 2524 clear_event_triggers(tr); 2525 2526 /* Disable any running events */ 2527 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0); 2528 2529 /* Access to events are within rcu_read_lock_sched() */ 2530 synchronize_sched(); 2531 2532 down_write(&trace_event_sem); 2533 __trace_remove_event_dirs(tr); 2534 tracefs_remove_recursive(tr->event_dir); 2535 up_write(&trace_event_sem); 2536 2537 tr->event_dir = NULL; 2538 2539 mutex_unlock(&event_mutex); 2540 2541 return 0; 2542 } 2543 2544 static __init int event_trace_memsetup(void) 2545 { 2546 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC); 2547 file_cachep = KMEM_CACHE(ftrace_event_file, SLAB_PANIC); 2548 return 0; 2549 } 2550 2551 static __init void 2552 early_enable_events(struct trace_array *tr, bool disable_first) 2553 { 2554 char *buf = bootup_event_buf; 2555 char *token; 2556 int ret; 2557 2558 while (true) { 2559 token = strsep(&buf, ","); 2560 2561 if (!token) 2562 break; 2563 if (!*token) 2564 continue; 2565 2566 /* Restarting syscalls requires that we stop them first */ 2567 if (disable_first) 2568 ftrace_set_clr_event(tr, token, 0); 2569 2570 ret = ftrace_set_clr_event(tr, token, 1); 2571 if (ret) 2572 pr_warn("Failed to enable trace event: %s\n", token); 2573 2574 /* Put back the comma to allow this to be called again */ 2575 if (buf) 2576 *(buf - 1) = ','; 2577 } 2578 } 2579 2580 static __init int event_trace_enable(void) 2581 { 2582 struct trace_array *tr = top_trace_array(); 2583 struct ftrace_event_call **iter, *call; 2584 int ret; 2585 2586 if (!tr) 2587 return -ENODEV; 2588 2589 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) { 2590 2591 call = *iter; 2592 ret = event_init(call); 2593 if (!ret) 2594 list_add(&call->list, &ftrace_events); 2595 } 2596 2597 /* 2598 * We need the top trace array to have a working set of trace 2599 * points at early init, before the debug files and directories 2600 * are created. Create the file entries now, and attach them 2601 * to the actual file dentries later. 2602 */ 2603 __trace_early_add_events(tr); 2604 2605 early_enable_events(tr, false); 2606 2607 trace_printk_start_comm(); 2608 2609 register_event_cmds(); 2610 2611 register_trigger_cmds(); 2612 2613 return 0; 2614 } 2615 2616 /* 2617 * event_trace_enable() is called from trace_event_init() first to 2618 * initialize events and perhaps start any events that are on the 2619 * command line. Unfortunately, there are some events that will not 2620 * start this early, like the system call tracepoints that need 2621 * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable() 2622 * is called before pid 1 starts, and this flag is never set, making 2623 * the syscall tracepoint never get reached, but the event is enabled 2624 * regardless (and not doing anything). 2625 */ 2626 static __init int event_trace_enable_again(void) 2627 { 2628 struct trace_array *tr; 2629 2630 tr = top_trace_array(); 2631 if (!tr) 2632 return -ENODEV; 2633 2634 early_enable_events(tr, true); 2635 2636 return 0; 2637 } 2638 2639 early_initcall(event_trace_enable_again); 2640 2641 static __init int event_trace_init(void) 2642 { 2643 struct trace_array *tr; 2644 struct dentry *d_tracer; 2645 struct dentry *entry; 2646 int ret; 2647 2648 tr = top_trace_array(); 2649 if (!tr) 2650 return -ENODEV; 2651 2652 d_tracer = tracing_init_dentry(); 2653 if (IS_ERR(d_tracer)) 2654 return 0; 2655 2656 entry = tracefs_create_file("available_events", 0444, d_tracer, 2657 tr, &ftrace_avail_fops); 2658 if (!entry) 2659 pr_warn("Could not create tracefs 'available_events' entry\n"); 2660 2661 if (trace_define_common_fields()) 2662 pr_warn("tracing: Failed to allocate common fields"); 2663 2664 ret = early_event_add_tracer(d_tracer, tr); 2665 if (ret) 2666 return ret; 2667 2668 #ifdef CONFIG_MODULES 2669 ret = register_module_notifier(&trace_module_nb); 2670 if (ret) 2671 pr_warn("Failed to register trace events module notifier\n"); 2672 #endif 2673 return 0; 2674 } 2675 2676 void __init trace_event_init(void) 2677 { 2678 event_trace_memsetup(); 2679 init_ftrace_syscalls(); 2680 event_trace_enable(); 2681 } 2682 2683 fs_initcall(event_trace_init); 2684 2685 #ifdef CONFIG_FTRACE_STARTUP_TEST 2686 2687 static DEFINE_SPINLOCK(test_spinlock); 2688 static DEFINE_SPINLOCK(test_spinlock_irq); 2689 static DEFINE_MUTEX(test_mutex); 2690 2691 static __init void test_work(struct work_struct *dummy) 2692 { 2693 spin_lock(&test_spinlock); 2694 spin_lock_irq(&test_spinlock_irq); 2695 udelay(1); 2696 spin_unlock_irq(&test_spinlock_irq); 2697 spin_unlock(&test_spinlock); 2698 2699 mutex_lock(&test_mutex); 2700 msleep(1); 2701 mutex_unlock(&test_mutex); 2702 } 2703 2704 static __init int event_test_thread(void *unused) 2705 { 2706 void *test_malloc; 2707 2708 test_malloc = kmalloc(1234, GFP_KERNEL); 2709 if (!test_malloc) 2710 pr_info("failed to kmalloc\n"); 2711 2712 schedule_on_each_cpu(test_work); 2713 2714 kfree(test_malloc); 2715 2716 set_current_state(TASK_INTERRUPTIBLE); 2717 while (!kthread_should_stop()) { 2718 schedule(); 2719 set_current_state(TASK_INTERRUPTIBLE); 2720 } 2721 __set_current_state(TASK_RUNNING); 2722 2723 return 0; 2724 } 2725 2726 /* 2727 * Do various things that may trigger events. 2728 */ 2729 static __init void event_test_stuff(void) 2730 { 2731 struct task_struct *test_thread; 2732 2733 test_thread = kthread_run(event_test_thread, NULL, "test-events"); 2734 msleep(1); 2735 kthread_stop(test_thread); 2736 } 2737 2738 /* 2739 * For every trace event defined, we will test each trace point separately, 2740 * and then by groups, and finally all trace points. 2741 */ 2742 static __init void event_trace_self_tests(void) 2743 { 2744 struct ftrace_subsystem_dir *dir; 2745 struct ftrace_event_file *file; 2746 struct ftrace_event_call *call; 2747 struct event_subsystem *system; 2748 struct trace_array *tr; 2749 int ret; 2750 2751 tr = top_trace_array(); 2752 if (!tr) 2753 return; 2754 2755 pr_info("Running tests on trace events:\n"); 2756 2757 list_for_each_entry(file, &tr->events, list) { 2758 2759 call = file->event_call; 2760 2761 /* Only test those that have a probe */ 2762 if (!call->class || !call->class->probe) 2763 continue; 2764 2765 /* 2766 * Testing syscall events here is pretty useless, but 2767 * we still do it if configured. But this is time consuming. 2768 * What we really need is a user thread to perform the 2769 * syscalls as we test. 2770 */ 2771 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS 2772 if (call->class->system && 2773 strcmp(call->class->system, "syscalls") == 0) 2774 continue; 2775 #endif 2776 2777 pr_info("Testing event %s: ", ftrace_event_name(call)); 2778 2779 /* 2780 * If an event is already enabled, someone is using 2781 * it and the self test should not be on. 2782 */ 2783 if (file->flags & FTRACE_EVENT_FL_ENABLED) { 2784 pr_warn("Enabled event during self test!\n"); 2785 WARN_ON_ONCE(1); 2786 continue; 2787 } 2788 2789 ftrace_event_enable_disable(file, 1); 2790 event_test_stuff(); 2791 ftrace_event_enable_disable(file, 0); 2792 2793 pr_cont("OK\n"); 2794 } 2795 2796 /* Now test at the sub system level */ 2797 2798 pr_info("Running tests on trace event systems:\n"); 2799 2800 list_for_each_entry(dir, &tr->systems, list) { 2801 2802 system = dir->subsystem; 2803 2804 /* the ftrace system is special, skip it */ 2805 if (strcmp(system->name, "ftrace") == 0) 2806 continue; 2807 2808 pr_info("Testing event system %s: ", system->name); 2809 2810 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1); 2811 if (WARN_ON_ONCE(ret)) { 2812 pr_warn("error enabling system %s\n", 2813 system->name); 2814 continue; 2815 } 2816 2817 event_test_stuff(); 2818 2819 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0); 2820 if (WARN_ON_ONCE(ret)) { 2821 pr_warn("error disabling system %s\n", 2822 system->name); 2823 continue; 2824 } 2825 2826 pr_cont("OK\n"); 2827 } 2828 2829 /* Test with all events enabled */ 2830 2831 pr_info("Running tests on all trace events:\n"); 2832 pr_info("Testing all events: "); 2833 2834 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1); 2835 if (WARN_ON_ONCE(ret)) { 2836 pr_warn("error enabling all events\n"); 2837 return; 2838 } 2839 2840 event_test_stuff(); 2841 2842 /* reset sysname */ 2843 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0); 2844 if (WARN_ON_ONCE(ret)) { 2845 pr_warn("error disabling all events\n"); 2846 return; 2847 } 2848 2849 pr_cont("OK\n"); 2850 } 2851 2852 #ifdef CONFIG_FUNCTION_TRACER 2853 2854 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable); 2855 2856 static void 2857 function_test_events_call(unsigned long ip, unsigned long parent_ip, 2858 struct ftrace_ops *op, struct pt_regs *pt_regs) 2859 { 2860 struct ring_buffer_event *event; 2861 struct ring_buffer *buffer; 2862 struct ftrace_entry *entry; 2863 unsigned long flags; 2864 long disabled; 2865 int cpu; 2866 int pc; 2867 2868 pc = preempt_count(); 2869 preempt_disable_notrace(); 2870 cpu = raw_smp_processor_id(); 2871 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu)); 2872 2873 if (disabled != 1) 2874 goto out; 2875 2876 local_save_flags(flags); 2877 2878 event = trace_current_buffer_lock_reserve(&buffer, 2879 TRACE_FN, sizeof(*entry), 2880 flags, pc); 2881 if (!event) 2882 goto out; 2883 entry = ring_buffer_event_data(event); 2884 entry->ip = ip; 2885 entry->parent_ip = parent_ip; 2886 2887 trace_buffer_unlock_commit(buffer, event, flags, pc); 2888 2889 out: 2890 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu)); 2891 preempt_enable_notrace(); 2892 } 2893 2894 static struct ftrace_ops trace_ops __initdata = 2895 { 2896 .func = function_test_events_call, 2897 .flags = FTRACE_OPS_FL_RECURSION_SAFE, 2898 }; 2899 2900 static __init void event_trace_self_test_with_function(void) 2901 { 2902 int ret; 2903 ret = register_ftrace_function(&trace_ops); 2904 if (WARN_ON(ret < 0)) { 2905 pr_info("Failed to enable function tracer for event tests\n"); 2906 return; 2907 } 2908 pr_info("Running tests again, along with the function tracer\n"); 2909 event_trace_self_tests(); 2910 unregister_ftrace_function(&trace_ops); 2911 } 2912 #else 2913 static __init void event_trace_self_test_with_function(void) 2914 { 2915 } 2916 #endif 2917 2918 static __init int event_trace_self_tests_init(void) 2919 { 2920 if (!tracing_selftest_disabled) { 2921 event_trace_self_tests(); 2922 event_trace_self_test_with_function(); 2923 } 2924 2925 return 0; 2926 } 2927 2928 late_initcall(event_trace_self_tests_init); 2929 2930 #endif 2931