1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * event tracer 4 * 5 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com> 6 * 7 * - Added format output of fields of the trace point. 8 * This was based off of work by Tom Zanussi <tzanussi@gmail.com>. 9 * 10 */ 11 12 #define pr_fmt(fmt) fmt 13 14 #include <linux/workqueue.h> 15 #include <linux/security.h> 16 #include <linux/spinlock.h> 17 #include <linux/kthread.h> 18 #include <linux/tracefs.h> 19 #include <linux/uaccess.h> 20 #include <linux/module.h> 21 #include <linux/ctype.h> 22 #include <linux/sort.h> 23 #include <linux/slab.h> 24 #include <linux/delay.h> 25 26 #include <trace/events/sched.h> 27 #include <trace/syscall.h> 28 29 #include <asm/setup.h> 30 31 #include "trace_output.h" 32 33 #undef TRACE_SYSTEM 34 #define TRACE_SYSTEM "TRACE_SYSTEM" 35 36 DEFINE_MUTEX(event_mutex); 37 38 LIST_HEAD(ftrace_events); 39 static LIST_HEAD(ftrace_generic_fields); 40 static LIST_HEAD(ftrace_common_fields); 41 42 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO) 43 44 static struct kmem_cache *field_cachep; 45 static struct kmem_cache *file_cachep; 46 47 static inline int system_refcount(struct event_subsystem *system) 48 { 49 return system->ref_count; 50 } 51 52 static int system_refcount_inc(struct event_subsystem *system) 53 { 54 return system->ref_count++; 55 } 56 57 static int system_refcount_dec(struct event_subsystem *system) 58 { 59 return --system->ref_count; 60 } 61 62 /* Double loops, do not use break, only goto's work */ 63 #define do_for_each_event_file(tr, file) \ 64 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \ 65 list_for_each_entry(file, &tr->events, list) 66 67 #define do_for_each_event_file_safe(tr, file) \ 68 list_for_each_entry(tr, &ftrace_trace_arrays, list) { \ 69 struct trace_event_file *___n; \ 70 list_for_each_entry_safe(file, ___n, &tr->events, list) 71 72 #define while_for_each_event_file() \ 73 } 74 75 static struct ftrace_event_field * 76 __find_event_field(struct list_head *head, char *name) 77 { 78 struct ftrace_event_field *field; 79 80 list_for_each_entry(field, head, link) { 81 if (!strcmp(field->name, name)) 82 return field; 83 } 84 85 return NULL; 86 } 87 88 struct ftrace_event_field * 89 trace_find_event_field(struct trace_event_call *call, char *name) 90 { 91 struct ftrace_event_field *field; 92 struct list_head *head; 93 94 head = trace_get_fields(call); 95 field = __find_event_field(head, name); 96 if (field) 97 return field; 98 99 field = __find_event_field(&ftrace_generic_fields, name); 100 if (field) 101 return field; 102 103 return __find_event_field(&ftrace_common_fields, name); 104 } 105 106 static int __trace_define_field(struct list_head *head, const char *type, 107 const char *name, int offset, int size, 108 int is_signed, int filter_type) 109 { 110 struct ftrace_event_field *field; 111 112 field = kmem_cache_alloc(field_cachep, GFP_TRACE); 113 if (!field) 114 return -ENOMEM; 115 116 field->name = name; 117 field->type = type; 118 119 if (filter_type == FILTER_OTHER) 120 field->filter_type = filter_assign_type(type); 121 else 122 field->filter_type = filter_type; 123 124 field->offset = offset; 125 field->size = size; 126 field->is_signed = is_signed; 127 128 list_add(&field->link, head); 129 130 return 0; 131 } 132 133 int trace_define_field(struct trace_event_call *call, const char *type, 134 const char *name, int offset, int size, int is_signed, 135 int filter_type) 136 { 137 struct list_head *head; 138 139 if (WARN_ON(!call->class)) 140 return 0; 141 142 head = trace_get_fields(call); 143 return __trace_define_field(head, type, name, offset, size, 144 is_signed, filter_type); 145 } 146 EXPORT_SYMBOL_GPL(trace_define_field); 147 148 #define __generic_field(type, item, filter_type) \ 149 ret = __trace_define_field(&ftrace_generic_fields, #type, \ 150 #item, 0, 0, is_signed_type(type), \ 151 filter_type); \ 152 if (ret) \ 153 return ret; 154 155 #define __common_field(type, item) \ 156 ret = __trace_define_field(&ftrace_common_fields, #type, \ 157 "common_" #item, \ 158 offsetof(typeof(ent), item), \ 159 sizeof(ent.item), \ 160 is_signed_type(type), FILTER_OTHER); \ 161 if (ret) \ 162 return ret; 163 164 static int trace_define_generic_fields(void) 165 { 166 int ret; 167 168 __generic_field(int, CPU, FILTER_CPU); 169 __generic_field(int, cpu, FILTER_CPU); 170 __generic_field(char *, COMM, FILTER_COMM); 171 __generic_field(char *, comm, FILTER_COMM); 172 173 return ret; 174 } 175 176 static int trace_define_common_fields(void) 177 { 178 int ret; 179 struct trace_entry ent; 180 181 __common_field(unsigned short, type); 182 __common_field(unsigned char, flags); 183 __common_field(unsigned char, preempt_count); 184 __common_field(int, pid); 185 186 return ret; 187 } 188 189 static void trace_destroy_fields(struct trace_event_call *call) 190 { 191 struct ftrace_event_field *field, *next; 192 struct list_head *head; 193 194 head = trace_get_fields(call); 195 list_for_each_entry_safe(field, next, head, link) { 196 list_del(&field->link); 197 kmem_cache_free(field_cachep, field); 198 } 199 } 200 201 /* 202 * run-time version of trace_event_get_offsets_<call>() that returns the last 203 * accessible offset of trace fields excluding __dynamic_array bytes 204 */ 205 int trace_event_get_offsets(struct trace_event_call *call) 206 { 207 struct ftrace_event_field *tail; 208 struct list_head *head; 209 210 head = trace_get_fields(call); 211 /* 212 * head->next points to the last field with the largest offset, 213 * since it was added last by trace_define_field() 214 */ 215 tail = list_first_entry(head, struct ftrace_event_field, link); 216 return tail->offset + tail->size; 217 } 218 219 int trace_event_raw_init(struct trace_event_call *call) 220 { 221 int id; 222 223 id = register_trace_event(&call->event); 224 if (!id) 225 return -ENODEV; 226 227 return 0; 228 } 229 EXPORT_SYMBOL_GPL(trace_event_raw_init); 230 231 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file) 232 { 233 struct trace_array *tr = trace_file->tr; 234 struct trace_array_cpu *data; 235 struct trace_pid_list *no_pid_list; 236 struct trace_pid_list *pid_list; 237 238 pid_list = rcu_dereference_raw(tr->filtered_pids); 239 no_pid_list = rcu_dereference_raw(tr->filtered_no_pids); 240 241 if (!pid_list && !no_pid_list) 242 return false; 243 244 data = this_cpu_ptr(tr->array_buffer.data); 245 246 return data->ignore_pid; 247 } 248 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid); 249 250 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer, 251 struct trace_event_file *trace_file, 252 unsigned long len) 253 { 254 struct trace_event_call *event_call = trace_file->event_call; 255 256 if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) && 257 trace_event_ignore_this_pid(trace_file)) 258 return NULL; 259 260 local_save_flags(fbuffer->flags); 261 fbuffer->pc = preempt_count(); 262 /* 263 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables 264 * preemption (adding one to the preempt_count). Since we are 265 * interested in the preempt_count at the time the tracepoint was 266 * hit, we need to subtract one to offset the increment. 267 */ 268 if (IS_ENABLED(CONFIG_PREEMPTION)) 269 fbuffer->pc--; 270 fbuffer->trace_file = trace_file; 271 272 fbuffer->event = 273 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file, 274 event_call->event.type, len, 275 fbuffer->flags, fbuffer->pc); 276 if (!fbuffer->event) 277 return NULL; 278 279 fbuffer->regs = NULL; 280 fbuffer->entry = ring_buffer_event_data(fbuffer->event); 281 return fbuffer->entry; 282 } 283 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve); 284 285 int trace_event_reg(struct trace_event_call *call, 286 enum trace_reg type, void *data) 287 { 288 struct trace_event_file *file = data; 289 290 WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT)); 291 switch (type) { 292 case TRACE_REG_REGISTER: 293 return tracepoint_probe_register(call->tp, 294 call->class->probe, 295 file); 296 case TRACE_REG_UNREGISTER: 297 tracepoint_probe_unregister(call->tp, 298 call->class->probe, 299 file); 300 return 0; 301 302 #ifdef CONFIG_PERF_EVENTS 303 case TRACE_REG_PERF_REGISTER: 304 return tracepoint_probe_register(call->tp, 305 call->class->perf_probe, 306 call); 307 case TRACE_REG_PERF_UNREGISTER: 308 tracepoint_probe_unregister(call->tp, 309 call->class->perf_probe, 310 call); 311 return 0; 312 case TRACE_REG_PERF_OPEN: 313 case TRACE_REG_PERF_CLOSE: 314 case TRACE_REG_PERF_ADD: 315 case TRACE_REG_PERF_DEL: 316 return 0; 317 #endif 318 } 319 return 0; 320 } 321 EXPORT_SYMBOL_GPL(trace_event_reg); 322 323 void trace_event_enable_cmd_record(bool enable) 324 { 325 struct trace_event_file *file; 326 struct trace_array *tr; 327 328 lockdep_assert_held(&event_mutex); 329 330 do_for_each_event_file(tr, file) { 331 332 if (!(file->flags & EVENT_FILE_FL_ENABLED)) 333 continue; 334 335 if (enable) { 336 tracing_start_cmdline_record(); 337 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags); 338 } else { 339 tracing_stop_cmdline_record(); 340 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags); 341 } 342 } while_for_each_event_file(); 343 } 344 345 void trace_event_enable_tgid_record(bool enable) 346 { 347 struct trace_event_file *file; 348 struct trace_array *tr; 349 350 lockdep_assert_held(&event_mutex); 351 352 do_for_each_event_file(tr, file) { 353 if (!(file->flags & EVENT_FILE_FL_ENABLED)) 354 continue; 355 356 if (enable) { 357 tracing_start_tgid_record(); 358 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags); 359 } else { 360 tracing_stop_tgid_record(); 361 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, 362 &file->flags); 363 } 364 } while_for_each_event_file(); 365 } 366 367 static int __ftrace_event_enable_disable(struct trace_event_file *file, 368 int enable, int soft_disable) 369 { 370 struct trace_event_call *call = file->event_call; 371 struct trace_array *tr = file->tr; 372 unsigned long file_flags = file->flags; 373 int ret = 0; 374 int disable; 375 376 switch (enable) { 377 case 0: 378 /* 379 * When soft_disable is set and enable is cleared, the sm_ref 380 * reference counter is decremented. If it reaches 0, we want 381 * to clear the SOFT_DISABLED flag but leave the event in the 382 * state that it was. That is, if the event was enabled and 383 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED 384 * is set we do not want the event to be enabled before we 385 * clear the bit. 386 * 387 * When soft_disable is not set but the SOFT_MODE flag is, 388 * we do nothing. Do not disable the tracepoint, otherwise 389 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work. 390 */ 391 if (soft_disable) { 392 if (atomic_dec_return(&file->sm_ref) > 0) 393 break; 394 disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED; 395 clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags); 396 } else 397 disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE); 398 399 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) { 400 clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags); 401 if (file->flags & EVENT_FILE_FL_RECORDED_CMD) { 402 tracing_stop_cmdline_record(); 403 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags); 404 } 405 406 if (file->flags & EVENT_FILE_FL_RECORDED_TGID) { 407 tracing_stop_tgid_record(); 408 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags); 409 } 410 411 call->class->reg(call, TRACE_REG_UNREGISTER, file); 412 } 413 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */ 414 if (file->flags & EVENT_FILE_FL_SOFT_MODE) 415 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags); 416 else 417 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags); 418 break; 419 case 1: 420 /* 421 * When soft_disable is set and enable is set, we want to 422 * register the tracepoint for the event, but leave the event 423 * as is. That means, if the event was already enabled, we do 424 * nothing (but set SOFT_MODE). If the event is disabled, we 425 * set SOFT_DISABLED before enabling the event tracepoint, so 426 * it still seems to be disabled. 427 */ 428 if (!soft_disable) 429 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags); 430 else { 431 if (atomic_inc_return(&file->sm_ref) > 1) 432 break; 433 set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags); 434 } 435 436 if (!(file->flags & EVENT_FILE_FL_ENABLED)) { 437 bool cmd = false, tgid = false; 438 439 /* Keep the event disabled, when going to SOFT_MODE. */ 440 if (soft_disable) 441 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags); 442 443 if (tr->trace_flags & TRACE_ITER_RECORD_CMD) { 444 cmd = true; 445 tracing_start_cmdline_record(); 446 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags); 447 } 448 449 if (tr->trace_flags & TRACE_ITER_RECORD_TGID) { 450 tgid = true; 451 tracing_start_tgid_record(); 452 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags); 453 } 454 455 ret = call->class->reg(call, TRACE_REG_REGISTER, file); 456 if (ret) { 457 if (cmd) 458 tracing_stop_cmdline_record(); 459 if (tgid) 460 tracing_stop_tgid_record(); 461 pr_info("event trace: Could not enable event " 462 "%s\n", trace_event_name(call)); 463 break; 464 } 465 set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags); 466 467 /* WAS_ENABLED gets set but never cleared. */ 468 set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags); 469 } 470 break; 471 } 472 473 /* Enable or disable use of trace_buffered_event */ 474 if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) != 475 (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) { 476 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED) 477 trace_buffered_event_enable(); 478 else 479 trace_buffered_event_disable(); 480 } 481 482 return ret; 483 } 484 485 int trace_event_enable_disable(struct trace_event_file *file, 486 int enable, int soft_disable) 487 { 488 return __ftrace_event_enable_disable(file, enable, soft_disable); 489 } 490 491 static int ftrace_event_enable_disable(struct trace_event_file *file, 492 int enable) 493 { 494 return __ftrace_event_enable_disable(file, enable, 0); 495 } 496 497 static void ftrace_clear_events(struct trace_array *tr) 498 { 499 struct trace_event_file *file; 500 501 mutex_lock(&event_mutex); 502 list_for_each_entry(file, &tr->events, list) { 503 ftrace_event_enable_disable(file, 0); 504 } 505 mutex_unlock(&event_mutex); 506 } 507 508 static void 509 event_filter_pid_sched_process_exit(void *data, struct task_struct *task) 510 { 511 struct trace_pid_list *pid_list; 512 struct trace_array *tr = data; 513 514 pid_list = rcu_dereference_raw(tr->filtered_pids); 515 trace_filter_add_remove_task(pid_list, NULL, task); 516 517 pid_list = rcu_dereference_raw(tr->filtered_no_pids); 518 trace_filter_add_remove_task(pid_list, NULL, task); 519 } 520 521 static void 522 event_filter_pid_sched_process_fork(void *data, 523 struct task_struct *self, 524 struct task_struct *task) 525 { 526 struct trace_pid_list *pid_list; 527 struct trace_array *tr = data; 528 529 pid_list = rcu_dereference_sched(tr->filtered_pids); 530 trace_filter_add_remove_task(pid_list, self, task); 531 532 pid_list = rcu_dereference_sched(tr->filtered_no_pids); 533 trace_filter_add_remove_task(pid_list, self, task); 534 } 535 536 void trace_event_follow_fork(struct trace_array *tr, bool enable) 537 { 538 if (enable) { 539 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork, 540 tr, INT_MIN); 541 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit, 542 tr, INT_MAX); 543 } else { 544 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork, 545 tr); 546 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit, 547 tr); 548 } 549 } 550 551 static void 552 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt, 553 struct task_struct *prev, struct task_struct *next) 554 { 555 struct trace_array *tr = data; 556 struct trace_pid_list *no_pid_list; 557 struct trace_pid_list *pid_list; 558 bool ret; 559 560 pid_list = rcu_dereference_sched(tr->filtered_pids); 561 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids); 562 563 /* 564 * Sched switch is funny, as we only want to ignore it 565 * in the notrace case if both prev and next should be ignored. 566 */ 567 ret = trace_ignore_this_task(NULL, no_pid_list, prev) && 568 trace_ignore_this_task(NULL, no_pid_list, next); 569 570 this_cpu_write(tr->array_buffer.data->ignore_pid, ret || 571 (trace_ignore_this_task(pid_list, NULL, prev) && 572 trace_ignore_this_task(pid_list, NULL, next))); 573 } 574 575 static void 576 event_filter_pid_sched_switch_probe_post(void *data, bool preempt, 577 struct task_struct *prev, struct task_struct *next) 578 { 579 struct trace_array *tr = data; 580 struct trace_pid_list *no_pid_list; 581 struct trace_pid_list *pid_list; 582 583 pid_list = rcu_dereference_sched(tr->filtered_pids); 584 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids); 585 586 this_cpu_write(tr->array_buffer.data->ignore_pid, 587 trace_ignore_this_task(pid_list, no_pid_list, next)); 588 } 589 590 static void 591 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task) 592 { 593 struct trace_array *tr = data; 594 struct trace_pid_list *no_pid_list; 595 struct trace_pid_list *pid_list; 596 597 /* Nothing to do if we are already tracing */ 598 if (!this_cpu_read(tr->array_buffer.data->ignore_pid)) 599 return; 600 601 pid_list = rcu_dereference_sched(tr->filtered_pids); 602 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids); 603 604 this_cpu_write(tr->array_buffer.data->ignore_pid, 605 trace_ignore_this_task(pid_list, no_pid_list, task)); 606 } 607 608 static void 609 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task) 610 { 611 struct trace_array *tr = data; 612 struct trace_pid_list *no_pid_list; 613 struct trace_pid_list *pid_list; 614 615 /* Nothing to do if we are not tracing */ 616 if (this_cpu_read(tr->array_buffer.data->ignore_pid)) 617 return; 618 619 pid_list = rcu_dereference_sched(tr->filtered_pids); 620 no_pid_list = rcu_dereference_sched(tr->filtered_no_pids); 621 622 /* Set tracing if current is enabled */ 623 this_cpu_write(tr->array_buffer.data->ignore_pid, 624 trace_ignore_this_task(pid_list, no_pid_list, current)); 625 } 626 627 static void unregister_pid_events(struct trace_array *tr) 628 { 629 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr); 630 unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr); 631 632 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr); 633 unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr); 634 635 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr); 636 unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr); 637 638 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr); 639 unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr); 640 } 641 642 static void __ftrace_clear_event_pids(struct trace_array *tr, int type) 643 { 644 struct trace_pid_list *pid_list; 645 struct trace_pid_list *no_pid_list; 646 struct trace_event_file *file; 647 int cpu; 648 649 pid_list = rcu_dereference_protected(tr->filtered_pids, 650 lockdep_is_held(&event_mutex)); 651 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids, 652 lockdep_is_held(&event_mutex)); 653 654 /* Make sure there's something to do */ 655 if (!pid_type_enabled(type, pid_list, no_pid_list)) 656 return; 657 658 if (!still_need_pid_events(type, pid_list, no_pid_list)) { 659 unregister_pid_events(tr); 660 661 list_for_each_entry(file, &tr->events, list) { 662 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags); 663 } 664 665 for_each_possible_cpu(cpu) 666 per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false; 667 } 668 669 if (type & TRACE_PIDS) 670 rcu_assign_pointer(tr->filtered_pids, NULL); 671 672 if (type & TRACE_NO_PIDS) 673 rcu_assign_pointer(tr->filtered_no_pids, NULL); 674 675 /* Wait till all users are no longer using pid filtering */ 676 tracepoint_synchronize_unregister(); 677 678 if ((type & TRACE_PIDS) && pid_list) 679 trace_free_pid_list(pid_list); 680 681 if ((type & TRACE_NO_PIDS) && no_pid_list) 682 trace_free_pid_list(no_pid_list); 683 } 684 685 static void ftrace_clear_event_pids(struct trace_array *tr, int type) 686 { 687 mutex_lock(&event_mutex); 688 __ftrace_clear_event_pids(tr, type); 689 mutex_unlock(&event_mutex); 690 } 691 692 static void __put_system(struct event_subsystem *system) 693 { 694 struct event_filter *filter = system->filter; 695 696 WARN_ON_ONCE(system_refcount(system) == 0); 697 if (system_refcount_dec(system)) 698 return; 699 700 list_del(&system->list); 701 702 if (filter) { 703 kfree(filter->filter_string); 704 kfree(filter); 705 } 706 kfree_const(system->name); 707 kfree(system); 708 } 709 710 static void __get_system(struct event_subsystem *system) 711 { 712 WARN_ON_ONCE(system_refcount(system) == 0); 713 system_refcount_inc(system); 714 } 715 716 static void __get_system_dir(struct trace_subsystem_dir *dir) 717 { 718 WARN_ON_ONCE(dir->ref_count == 0); 719 dir->ref_count++; 720 __get_system(dir->subsystem); 721 } 722 723 static void __put_system_dir(struct trace_subsystem_dir *dir) 724 { 725 WARN_ON_ONCE(dir->ref_count == 0); 726 /* If the subsystem is about to be freed, the dir must be too */ 727 WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1); 728 729 __put_system(dir->subsystem); 730 if (!--dir->ref_count) 731 kfree(dir); 732 } 733 734 static void put_system(struct trace_subsystem_dir *dir) 735 { 736 mutex_lock(&event_mutex); 737 __put_system_dir(dir); 738 mutex_unlock(&event_mutex); 739 } 740 741 static void remove_subsystem(struct trace_subsystem_dir *dir) 742 { 743 if (!dir) 744 return; 745 746 if (!--dir->nr_events) { 747 tracefs_remove(dir->entry); 748 list_del(&dir->list); 749 __put_system_dir(dir); 750 } 751 } 752 753 static void remove_event_file_dir(struct trace_event_file *file) 754 { 755 struct dentry *dir = file->dir; 756 struct dentry *child; 757 758 if (dir) { 759 spin_lock(&dir->d_lock); /* probably unneeded */ 760 list_for_each_entry(child, &dir->d_subdirs, d_child) { 761 if (d_really_is_positive(child)) /* probably unneeded */ 762 d_inode(child)->i_private = NULL; 763 } 764 spin_unlock(&dir->d_lock); 765 766 tracefs_remove(dir); 767 } 768 769 list_del(&file->list); 770 remove_subsystem(file->system); 771 free_event_filter(file->filter); 772 kmem_cache_free(file_cachep, file); 773 } 774 775 /* 776 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events. 777 */ 778 static int 779 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match, 780 const char *sub, const char *event, int set) 781 { 782 struct trace_event_file *file; 783 struct trace_event_call *call; 784 const char *name; 785 int ret = -EINVAL; 786 int eret = 0; 787 788 list_for_each_entry(file, &tr->events, list) { 789 790 call = file->event_call; 791 name = trace_event_name(call); 792 793 if (!name || !call->class || !call->class->reg) 794 continue; 795 796 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) 797 continue; 798 799 if (match && 800 strcmp(match, name) != 0 && 801 strcmp(match, call->class->system) != 0) 802 continue; 803 804 if (sub && strcmp(sub, call->class->system) != 0) 805 continue; 806 807 if (event && strcmp(event, name) != 0) 808 continue; 809 810 ret = ftrace_event_enable_disable(file, set); 811 812 /* 813 * Save the first error and return that. Some events 814 * may still have been enabled, but let the user 815 * know that something went wrong. 816 */ 817 if (ret && !eret) 818 eret = ret; 819 820 ret = eret; 821 } 822 823 return ret; 824 } 825 826 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match, 827 const char *sub, const char *event, int set) 828 { 829 int ret; 830 831 mutex_lock(&event_mutex); 832 ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set); 833 mutex_unlock(&event_mutex); 834 835 return ret; 836 } 837 838 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set) 839 { 840 char *event = NULL, *sub = NULL, *match; 841 int ret; 842 843 if (!tr) 844 return -ENOENT; 845 /* 846 * The buf format can be <subsystem>:<event-name> 847 * *:<event-name> means any event by that name. 848 * :<event-name> is the same. 849 * 850 * <subsystem>:* means all events in that subsystem 851 * <subsystem>: means the same. 852 * 853 * <name> (no ':') means all events in a subsystem with 854 * the name <name> or any event that matches <name> 855 */ 856 857 match = strsep(&buf, ":"); 858 if (buf) { 859 sub = match; 860 event = buf; 861 match = NULL; 862 863 if (!strlen(sub) || strcmp(sub, "*") == 0) 864 sub = NULL; 865 if (!strlen(event) || strcmp(event, "*") == 0) 866 event = NULL; 867 } 868 869 ret = __ftrace_set_clr_event(tr, match, sub, event, set); 870 871 /* Put back the colon to allow this to be called again */ 872 if (buf) 873 *(buf - 1) = ':'; 874 875 return ret; 876 } 877 878 /** 879 * trace_set_clr_event - enable or disable an event 880 * @system: system name to match (NULL for any system) 881 * @event: event name to match (NULL for all events, within system) 882 * @set: 1 to enable, 0 to disable 883 * 884 * This is a way for other parts of the kernel to enable or disable 885 * event recording. 886 * 887 * Returns 0 on success, -EINVAL if the parameters do not match any 888 * registered events. 889 */ 890 int trace_set_clr_event(const char *system, const char *event, int set) 891 { 892 struct trace_array *tr = top_trace_array(); 893 894 if (!tr) 895 return -ENODEV; 896 897 return __ftrace_set_clr_event(tr, NULL, system, event, set); 898 } 899 EXPORT_SYMBOL_GPL(trace_set_clr_event); 900 901 /** 902 * trace_array_set_clr_event - enable or disable an event for a trace array. 903 * @tr: concerned trace array. 904 * @system: system name to match (NULL for any system) 905 * @event: event name to match (NULL for all events, within system) 906 * @enable: true to enable, false to disable 907 * 908 * This is a way for other parts of the kernel to enable or disable 909 * event recording. 910 * 911 * Returns 0 on success, -EINVAL if the parameters do not match any 912 * registered events. 913 */ 914 int trace_array_set_clr_event(struct trace_array *tr, const char *system, 915 const char *event, bool enable) 916 { 917 int set; 918 919 if (!tr) 920 return -ENOENT; 921 922 set = (enable == true) ? 1 : 0; 923 return __ftrace_set_clr_event(tr, NULL, system, event, set); 924 } 925 EXPORT_SYMBOL_GPL(trace_array_set_clr_event); 926 927 /* 128 should be much more than enough */ 928 #define EVENT_BUF_SIZE 127 929 930 static ssize_t 931 ftrace_event_write(struct file *file, const char __user *ubuf, 932 size_t cnt, loff_t *ppos) 933 { 934 struct trace_parser parser; 935 struct seq_file *m = file->private_data; 936 struct trace_array *tr = m->private; 937 ssize_t read, ret; 938 939 if (!cnt) 940 return 0; 941 942 ret = tracing_update_buffers(); 943 if (ret < 0) 944 return ret; 945 946 if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1)) 947 return -ENOMEM; 948 949 read = trace_get_user(&parser, ubuf, cnt, ppos); 950 951 if (read >= 0 && trace_parser_loaded((&parser))) { 952 int set = 1; 953 954 if (*parser.buffer == '!') 955 set = 0; 956 957 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set); 958 if (ret) 959 goto out_put; 960 } 961 962 ret = read; 963 964 out_put: 965 trace_parser_put(&parser); 966 967 return ret; 968 } 969 970 static void * 971 t_next(struct seq_file *m, void *v, loff_t *pos) 972 { 973 struct trace_event_file *file = v; 974 struct trace_event_call *call; 975 struct trace_array *tr = m->private; 976 977 (*pos)++; 978 979 list_for_each_entry_continue(file, &tr->events, list) { 980 call = file->event_call; 981 /* 982 * The ftrace subsystem is for showing formats only. 983 * They can not be enabled or disabled via the event files. 984 */ 985 if (call->class && call->class->reg && 986 !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) 987 return file; 988 } 989 990 return NULL; 991 } 992 993 static void *t_start(struct seq_file *m, loff_t *pos) 994 { 995 struct trace_event_file *file; 996 struct trace_array *tr = m->private; 997 loff_t l; 998 999 mutex_lock(&event_mutex); 1000 1001 file = list_entry(&tr->events, struct trace_event_file, list); 1002 for (l = 0; l <= *pos; ) { 1003 file = t_next(m, file, &l); 1004 if (!file) 1005 break; 1006 } 1007 return file; 1008 } 1009 1010 static void * 1011 s_next(struct seq_file *m, void *v, loff_t *pos) 1012 { 1013 struct trace_event_file *file = v; 1014 struct trace_array *tr = m->private; 1015 1016 (*pos)++; 1017 1018 list_for_each_entry_continue(file, &tr->events, list) { 1019 if (file->flags & EVENT_FILE_FL_ENABLED) 1020 return file; 1021 } 1022 1023 return NULL; 1024 } 1025 1026 static void *s_start(struct seq_file *m, loff_t *pos) 1027 { 1028 struct trace_event_file *file; 1029 struct trace_array *tr = m->private; 1030 loff_t l; 1031 1032 mutex_lock(&event_mutex); 1033 1034 file = list_entry(&tr->events, struct trace_event_file, list); 1035 for (l = 0; l <= *pos; ) { 1036 file = s_next(m, file, &l); 1037 if (!file) 1038 break; 1039 } 1040 return file; 1041 } 1042 1043 static int t_show(struct seq_file *m, void *v) 1044 { 1045 struct trace_event_file *file = v; 1046 struct trace_event_call *call = file->event_call; 1047 1048 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) 1049 seq_printf(m, "%s:", call->class->system); 1050 seq_printf(m, "%s\n", trace_event_name(call)); 1051 1052 return 0; 1053 } 1054 1055 static void t_stop(struct seq_file *m, void *p) 1056 { 1057 mutex_unlock(&event_mutex); 1058 } 1059 1060 static void * 1061 __next(struct seq_file *m, void *v, loff_t *pos, int type) 1062 { 1063 struct trace_array *tr = m->private; 1064 struct trace_pid_list *pid_list; 1065 1066 if (type == TRACE_PIDS) 1067 pid_list = rcu_dereference_sched(tr->filtered_pids); 1068 else 1069 pid_list = rcu_dereference_sched(tr->filtered_no_pids); 1070 1071 return trace_pid_next(pid_list, v, pos); 1072 } 1073 1074 static void * 1075 p_next(struct seq_file *m, void *v, loff_t *pos) 1076 { 1077 return __next(m, v, pos, TRACE_PIDS); 1078 } 1079 1080 static void * 1081 np_next(struct seq_file *m, void *v, loff_t *pos) 1082 { 1083 return __next(m, v, pos, TRACE_NO_PIDS); 1084 } 1085 1086 static void *__start(struct seq_file *m, loff_t *pos, int type) 1087 __acquires(RCU) 1088 { 1089 struct trace_pid_list *pid_list; 1090 struct trace_array *tr = m->private; 1091 1092 /* 1093 * Grab the mutex, to keep calls to p_next() having the same 1094 * tr->filtered_pids as p_start() has. 1095 * If we just passed the tr->filtered_pids around, then RCU would 1096 * have been enough, but doing that makes things more complex. 1097 */ 1098 mutex_lock(&event_mutex); 1099 rcu_read_lock_sched(); 1100 1101 if (type == TRACE_PIDS) 1102 pid_list = rcu_dereference_sched(tr->filtered_pids); 1103 else 1104 pid_list = rcu_dereference_sched(tr->filtered_no_pids); 1105 1106 if (!pid_list) 1107 return NULL; 1108 1109 return trace_pid_start(pid_list, pos); 1110 } 1111 1112 static void *p_start(struct seq_file *m, loff_t *pos) 1113 __acquires(RCU) 1114 { 1115 return __start(m, pos, TRACE_PIDS); 1116 } 1117 1118 static void *np_start(struct seq_file *m, loff_t *pos) 1119 __acquires(RCU) 1120 { 1121 return __start(m, pos, TRACE_NO_PIDS); 1122 } 1123 1124 static void p_stop(struct seq_file *m, void *p) 1125 __releases(RCU) 1126 { 1127 rcu_read_unlock_sched(); 1128 mutex_unlock(&event_mutex); 1129 } 1130 1131 static ssize_t 1132 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 1133 loff_t *ppos) 1134 { 1135 struct trace_event_file *file; 1136 unsigned long flags; 1137 char buf[4] = "0"; 1138 1139 mutex_lock(&event_mutex); 1140 file = event_file_data(filp); 1141 if (likely(file)) 1142 flags = file->flags; 1143 mutex_unlock(&event_mutex); 1144 1145 if (!file) 1146 return -ENODEV; 1147 1148 if (flags & EVENT_FILE_FL_ENABLED && 1149 !(flags & EVENT_FILE_FL_SOFT_DISABLED)) 1150 strcpy(buf, "1"); 1151 1152 if (flags & EVENT_FILE_FL_SOFT_DISABLED || 1153 flags & EVENT_FILE_FL_SOFT_MODE) 1154 strcat(buf, "*"); 1155 1156 strcat(buf, "\n"); 1157 1158 return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf)); 1159 } 1160 1161 static ssize_t 1162 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, 1163 loff_t *ppos) 1164 { 1165 struct trace_event_file *file; 1166 unsigned long val; 1167 int ret; 1168 1169 ret = kstrtoul_from_user(ubuf, cnt, 10, &val); 1170 if (ret) 1171 return ret; 1172 1173 ret = tracing_update_buffers(); 1174 if (ret < 0) 1175 return ret; 1176 1177 switch (val) { 1178 case 0: 1179 case 1: 1180 ret = -ENODEV; 1181 mutex_lock(&event_mutex); 1182 file = event_file_data(filp); 1183 if (likely(file)) 1184 ret = ftrace_event_enable_disable(file, val); 1185 mutex_unlock(&event_mutex); 1186 break; 1187 1188 default: 1189 return -EINVAL; 1190 } 1191 1192 *ppos += cnt; 1193 1194 return ret ? ret : cnt; 1195 } 1196 1197 static ssize_t 1198 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt, 1199 loff_t *ppos) 1200 { 1201 const char set_to_char[4] = { '?', '0', '1', 'X' }; 1202 struct trace_subsystem_dir *dir = filp->private_data; 1203 struct event_subsystem *system = dir->subsystem; 1204 struct trace_event_call *call; 1205 struct trace_event_file *file; 1206 struct trace_array *tr = dir->tr; 1207 char buf[2]; 1208 int set = 0; 1209 int ret; 1210 1211 mutex_lock(&event_mutex); 1212 list_for_each_entry(file, &tr->events, list) { 1213 call = file->event_call; 1214 if (!trace_event_name(call) || !call->class || !call->class->reg) 1215 continue; 1216 1217 if (system && strcmp(call->class->system, system->name) != 0) 1218 continue; 1219 1220 /* 1221 * We need to find out if all the events are set 1222 * or if all events or cleared, or if we have 1223 * a mixture. 1224 */ 1225 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED)); 1226 1227 /* 1228 * If we have a mixture, no need to look further. 1229 */ 1230 if (set == 3) 1231 break; 1232 } 1233 mutex_unlock(&event_mutex); 1234 1235 buf[0] = set_to_char[set]; 1236 buf[1] = '\n'; 1237 1238 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); 1239 1240 return ret; 1241 } 1242 1243 static ssize_t 1244 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, 1245 loff_t *ppos) 1246 { 1247 struct trace_subsystem_dir *dir = filp->private_data; 1248 struct event_subsystem *system = dir->subsystem; 1249 const char *name = NULL; 1250 unsigned long val; 1251 ssize_t ret; 1252 1253 ret = kstrtoul_from_user(ubuf, cnt, 10, &val); 1254 if (ret) 1255 return ret; 1256 1257 ret = tracing_update_buffers(); 1258 if (ret < 0) 1259 return ret; 1260 1261 if (val != 0 && val != 1) 1262 return -EINVAL; 1263 1264 /* 1265 * Opening of "enable" adds a ref count to system, 1266 * so the name is safe to use. 1267 */ 1268 if (system) 1269 name = system->name; 1270 1271 ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val); 1272 if (ret) 1273 goto out; 1274 1275 ret = cnt; 1276 1277 out: 1278 *ppos += cnt; 1279 1280 return ret; 1281 } 1282 1283 enum { 1284 FORMAT_HEADER = 1, 1285 FORMAT_FIELD_SEPERATOR = 2, 1286 FORMAT_PRINTFMT = 3, 1287 }; 1288 1289 static void *f_next(struct seq_file *m, void *v, loff_t *pos) 1290 { 1291 struct trace_event_call *call = event_file_data(m->private); 1292 struct list_head *common_head = &ftrace_common_fields; 1293 struct list_head *head = trace_get_fields(call); 1294 struct list_head *node = v; 1295 1296 (*pos)++; 1297 1298 switch ((unsigned long)v) { 1299 case FORMAT_HEADER: 1300 node = common_head; 1301 break; 1302 1303 case FORMAT_FIELD_SEPERATOR: 1304 node = head; 1305 break; 1306 1307 case FORMAT_PRINTFMT: 1308 /* all done */ 1309 return NULL; 1310 } 1311 1312 node = node->prev; 1313 if (node == common_head) 1314 return (void *)FORMAT_FIELD_SEPERATOR; 1315 else if (node == head) 1316 return (void *)FORMAT_PRINTFMT; 1317 else 1318 return node; 1319 } 1320 1321 static int f_show(struct seq_file *m, void *v) 1322 { 1323 struct trace_event_call *call = event_file_data(m->private); 1324 struct ftrace_event_field *field; 1325 const char *array_descriptor; 1326 1327 switch ((unsigned long)v) { 1328 case FORMAT_HEADER: 1329 seq_printf(m, "name: %s\n", trace_event_name(call)); 1330 seq_printf(m, "ID: %d\n", call->event.type); 1331 seq_puts(m, "format:\n"); 1332 return 0; 1333 1334 case FORMAT_FIELD_SEPERATOR: 1335 seq_putc(m, '\n'); 1336 return 0; 1337 1338 case FORMAT_PRINTFMT: 1339 seq_printf(m, "\nprint fmt: %s\n", 1340 call->print_fmt); 1341 return 0; 1342 } 1343 1344 field = list_entry(v, struct ftrace_event_field, link); 1345 /* 1346 * Smartly shows the array type(except dynamic array). 1347 * Normal: 1348 * field:TYPE VAR 1349 * If TYPE := TYPE[LEN], it is shown: 1350 * field:TYPE VAR[LEN] 1351 */ 1352 array_descriptor = strchr(field->type, '['); 1353 1354 if (str_has_prefix(field->type, "__data_loc")) 1355 array_descriptor = NULL; 1356 1357 if (!array_descriptor) 1358 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n", 1359 field->type, field->name, field->offset, 1360 field->size, !!field->is_signed); 1361 else 1362 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n", 1363 (int)(array_descriptor - field->type), 1364 field->type, field->name, 1365 array_descriptor, field->offset, 1366 field->size, !!field->is_signed); 1367 1368 return 0; 1369 } 1370 1371 static void *f_start(struct seq_file *m, loff_t *pos) 1372 { 1373 void *p = (void *)FORMAT_HEADER; 1374 loff_t l = 0; 1375 1376 /* ->stop() is called even if ->start() fails */ 1377 mutex_lock(&event_mutex); 1378 if (!event_file_data(m->private)) 1379 return ERR_PTR(-ENODEV); 1380 1381 while (l < *pos && p) 1382 p = f_next(m, p, &l); 1383 1384 return p; 1385 } 1386 1387 static void f_stop(struct seq_file *m, void *p) 1388 { 1389 mutex_unlock(&event_mutex); 1390 } 1391 1392 static const struct seq_operations trace_format_seq_ops = { 1393 .start = f_start, 1394 .next = f_next, 1395 .stop = f_stop, 1396 .show = f_show, 1397 }; 1398 1399 static int trace_format_open(struct inode *inode, struct file *file) 1400 { 1401 struct seq_file *m; 1402 int ret; 1403 1404 /* Do we want to hide event format files on tracefs lockdown? */ 1405 1406 ret = seq_open(file, &trace_format_seq_ops); 1407 if (ret < 0) 1408 return ret; 1409 1410 m = file->private_data; 1411 m->private = file; 1412 1413 return 0; 1414 } 1415 1416 static ssize_t 1417 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) 1418 { 1419 int id = (long)event_file_data(filp); 1420 char buf[32]; 1421 int len; 1422 1423 if (unlikely(!id)) 1424 return -ENODEV; 1425 1426 len = sprintf(buf, "%d\n", id); 1427 1428 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len); 1429 } 1430 1431 static ssize_t 1432 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt, 1433 loff_t *ppos) 1434 { 1435 struct trace_event_file *file; 1436 struct trace_seq *s; 1437 int r = -ENODEV; 1438 1439 if (*ppos) 1440 return 0; 1441 1442 s = kmalloc(sizeof(*s), GFP_KERNEL); 1443 1444 if (!s) 1445 return -ENOMEM; 1446 1447 trace_seq_init(s); 1448 1449 mutex_lock(&event_mutex); 1450 file = event_file_data(filp); 1451 if (file) 1452 print_event_filter(file, s); 1453 mutex_unlock(&event_mutex); 1454 1455 if (file) 1456 r = simple_read_from_buffer(ubuf, cnt, ppos, 1457 s->buffer, trace_seq_used(s)); 1458 1459 kfree(s); 1460 1461 return r; 1462 } 1463 1464 static ssize_t 1465 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, 1466 loff_t *ppos) 1467 { 1468 struct trace_event_file *file; 1469 char *buf; 1470 int err = -ENODEV; 1471 1472 if (cnt >= PAGE_SIZE) 1473 return -EINVAL; 1474 1475 buf = memdup_user_nul(ubuf, cnt); 1476 if (IS_ERR(buf)) 1477 return PTR_ERR(buf); 1478 1479 mutex_lock(&event_mutex); 1480 file = event_file_data(filp); 1481 if (file) 1482 err = apply_event_filter(file, buf); 1483 mutex_unlock(&event_mutex); 1484 1485 kfree(buf); 1486 if (err < 0) 1487 return err; 1488 1489 *ppos += cnt; 1490 1491 return cnt; 1492 } 1493 1494 static LIST_HEAD(event_subsystems); 1495 1496 static int subsystem_open(struct inode *inode, struct file *filp) 1497 { 1498 struct event_subsystem *system = NULL; 1499 struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */ 1500 struct trace_array *tr; 1501 int ret; 1502 1503 if (tracing_is_disabled()) 1504 return -ENODEV; 1505 1506 /* Make sure the system still exists */ 1507 mutex_lock(&event_mutex); 1508 mutex_lock(&trace_types_lock); 1509 list_for_each_entry(tr, &ftrace_trace_arrays, list) { 1510 list_for_each_entry(dir, &tr->systems, list) { 1511 if (dir == inode->i_private) { 1512 /* Don't open systems with no events */ 1513 if (dir->nr_events) { 1514 __get_system_dir(dir); 1515 system = dir->subsystem; 1516 } 1517 goto exit_loop; 1518 } 1519 } 1520 } 1521 exit_loop: 1522 mutex_unlock(&trace_types_lock); 1523 mutex_unlock(&event_mutex); 1524 1525 if (!system) 1526 return -ENODEV; 1527 1528 /* Some versions of gcc think dir can be uninitialized here */ 1529 WARN_ON(!dir); 1530 1531 /* Still need to increment the ref count of the system */ 1532 if (trace_array_get(tr) < 0) { 1533 put_system(dir); 1534 return -ENODEV; 1535 } 1536 1537 ret = tracing_open_generic(inode, filp); 1538 if (ret < 0) { 1539 trace_array_put(tr); 1540 put_system(dir); 1541 } 1542 1543 return ret; 1544 } 1545 1546 static int system_tr_open(struct inode *inode, struct file *filp) 1547 { 1548 struct trace_subsystem_dir *dir; 1549 struct trace_array *tr = inode->i_private; 1550 int ret; 1551 1552 /* Make a temporary dir that has no system but points to tr */ 1553 dir = kzalloc(sizeof(*dir), GFP_KERNEL); 1554 if (!dir) 1555 return -ENOMEM; 1556 1557 ret = tracing_open_generic_tr(inode, filp); 1558 if (ret < 0) { 1559 kfree(dir); 1560 return ret; 1561 } 1562 dir->tr = tr; 1563 filp->private_data = dir; 1564 1565 return 0; 1566 } 1567 1568 static int subsystem_release(struct inode *inode, struct file *file) 1569 { 1570 struct trace_subsystem_dir *dir = file->private_data; 1571 1572 trace_array_put(dir->tr); 1573 1574 /* 1575 * If dir->subsystem is NULL, then this is a temporary 1576 * descriptor that was made for a trace_array to enable 1577 * all subsystems. 1578 */ 1579 if (dir->subsystem) 1580 put_system(dir); 1581 else 1582 kfree(dir); 1583 1584 return 0; 1585 } 1586 1587 static ssize_t 1588 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt, 1589 loff_t *ppos) 1590 { 1591 struct trace_subsystem_dir *dir = filp->private_data; 1592 struct event_subsystem *system = dir->subsystem; 1593 struct trace_seq *s; 1594 int r; 1595 1596 if (*ppos) 1597 return 0; 1598 1599 s = kmalloc(sizeof(*s), GFP_KERNEL); 1600 if (!s) 1601 return -ENOMEM; 1602 1603 trace_seq_init(s); 1604 1605 print_subsystem_event_filter(system, s); 1606 r = simple_read_from_buffer(ubuf, cnt, ppos, 1607 s->buffer, trace_seq_used(s)); 1608 1609 kfree(s); 1610 1611 return r; 1612 } 1613 1614 static ssize_t 1615 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, 1616 loff_t *ppos) 1617 { 1618 struct trace_subsystem_dir *dir = filp->private_data; 1619 char *buf; 1620 int err; 1621 1622 if (cnt >= PAGE_SIZE) 1623 return -EINVAL; 1624 1625 buf = memdup_user_nul(ubuf, cnt); 1626 if (IS_ERR(buf)) 1627 return PTR_ERR(buf); 1628 1629 err = apply_subsystem_event_filter(dir, buf); 1630 kfree(buf); 1631 if (err < 0) 1632 return err; 1633 1634 *ppos += cnt; 1635 1636 return cnt; 1637 } 1638 1639 static ssize_t 1640 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) 1641 { 1642 int (*func)(struct trace_seq *s) = filp->private_data; 1643 struct trace_seq *s; 1644 int r; 1645 1646 if (*ppos) 1647 return 0; 1648 1649 s = kmalloc(sizeof(*s), GFP_KERNEL); 1650 if (!s) 1651 return -ENOMEM; 1652 1653 trace_seq_init(s); 1654 1655 func(s); 1656 r = simple_read_from_buffer(ubuf, cnt, ppos, 1657 s->buffer, trace_seq_used(s)); 1658 1659 kfree(s); 1660 1661 return r; 1662 } 1663 1664 static void ignore_task_cpu(void *data) 1665 { 1666 struct trace_array *tr = data; 1667 struct trace_pid_list *pid_list; 1668 struct trace_pid_list *no_pid_list; 1669 1670 /* 1671 * This function is called by on_each_cpu() while the 1672 * event_mutex is held. 1673 */ 1674 pid_list = rcu_dereference_protected(tr->filtered_pids, 1675 mutex_is_locked(&event_mutex)); 1676 no_pid_list = rcu_dereference_protected(tr->filtered_no_pids, 1677 mutex_is_locked(&event_mutex)); 1678 1679 this_cpu_write(tr->array_buffer.data->ignore_pid, 1680 trace_ignore_this_task(pid_list, no_pid_list, current)); 1681 } 1682 1683 static void register_pid_events(struct trace_array *tr) 1684 { 1685 /* 1686 * Register a probe that is called before all other probes 1687 * to set ignore_pid if next or prev do not match. 1688 * Register a probe this is called after all other probes 1689 * to only keep ignore_pid set if next pid matches. 1690 */ 1691 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre, 1692 tr, INT_MAX); 1693 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post, 1694 tr, 0); 1695 1696 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, 1697 tr, INT_MAX); 1698 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, 1699 tr, 0); 1700 1701 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, 1702 tr, INT_MAX); 1703 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, 1704 tr, 0); 1705 1706 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre, 1707 tr, INT_MAX); 1708 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post, 1709 tr, 0); 1710 } 1711 1712 static ssize_t 1713 event_pid_write(struct file *filp, const char __user *ubuf, 1714 size_t cnt, loff_t *ppos, int type) 1715 { 1716 struct seq_file *m = filp->private_data; 1717 struct trace_array *tr = m->private; 1718 struct trace_pid_list *filtered_pids = NULL; 1719 struct trace_pid_list *other_pids = NULL; 1720 struct trace_pid_list *pid_list; 1721 struct trace_event_file *file; 1722 ssize_t ret; 1723 1724 if (!cnt) 1725 return 0; 1726 1727 ret = tracing_update_buffers(); 1728 if (ret < 0) 1729 return ret; 1730 1731 mutex_lock(&event_mutex); 1732 1733 if (type == TRACE_PIDS) { 1734 filtered_pids = rcu_dereference_protected(tr->filtered_pids, 1735 lockdep_is_held(&event_mutex)); 1736 other_pids = rcu_dereference_protected(tr->filtered_no_pids, 1737 lockdep_is_held(&event_mutex)); 1738 } else { 1739 filtered_pids = rcu_dereference_protected(tr->filtered_no_pids, 1740 lockdep_is_held(&event_mutex)); 1741 other_pids = rcu_dereference_protected(tr->filtered_pids, 1742 lockdep_is_held(&event_mutex)); 1743 } 1744 1745 ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt); 1746 if (ret < 0) 1747 goto out; 1748 1749 if (type == TRACE_PIDS) 1750 rcu_assign_pointer(tr->filtered_pids, pid_list); 1751 else 1752 rcu_assign_pointer(tr->filtered_no_pids, pid_list); 1753 1754 list_for_each_entry(file, &tr->events, list) { 1755 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags); 1756 } 1757 1758 if (filtered_pids) { 1759 tracepoint_synchronize_unregister(); 1760 trace_free_pid_list(filtered_pids); 1761 } else if (pid_list && !other_pids) { 1762 register_pid_events(tr); 1763 } 1764 1765 /* 1766 * Ignoring of pids is done at task switch. But we have to 1767 * check for those tasks that are currently running. 1768 * Always do this in case a pid was appended or removed. 1769 */ 1770 on_each_cpu(ignore_task_cpu, tr, 1); 1771 1772 out: 1773 mutex_unlock(&event_mutex); 1774 1775 if (ret > 0) 1776 *ppos += ret; 1777 1778 return ret; 1779 } 1780 1781 static ssize_t 1782 ftrace_event_pid_write(struct file *filp, const char __user *ubuf, 1783 size_t cnt, loff_t *ppos) 1784 { 1785 return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS); 1786 } 1787 1788 static ssize_t 1789 ftrace_event_npid_write(struct file *filp, const char __user *ubuf, 1790 size_t cnt, loff_t *ppos) 1791 { 1792 return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS); 1793 } 1794 1795 static int ftrace_event_avail_open(struct inode *inode, struct file *file); 1796 static int ftrace_event_set_open(struct inode *inode, struct file *file); 1797 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file); 1798 static int ftrace_event_set_npid_open(struct inode *inode, struct file *file); 1799 static int ftrace_event_release(struct inode *inode, struct file *file); 1800 1801 static const struct seq_operations show_event_seq_ops = { 1802 .start = t_start, 1803 .next = t_next, 1804 .show = t_show, 1805 .stop = t_stop, 1806 }; 1807 1808 static const struct seq_operations show_set_event_seq_ops = { 1809 .start = s_start, 1810 .next = s_next, 1811 .show = t_show, 1812 .stop = t_stop, 1813 }; 1814 1815 static const struct seq_operations show_set_pid_seq_ops = { 1816 .start = p_start, 1817 .next = p_next, 1818 .show = trace_pid_show, 1819 .stop = p_stop, 1820 }; 1821 1822 static const struct seq_operations show_set_no_pid_seq_ops = { 1823 .start = np_start, 1824 .next = np_next, 1825 .show = trace_pid_show, 1826 .stop = p_stop, 1827 }; 1828 1829 static const struct file_operations ftrace_avail_fops = { 1830 .open = ftrace_event_avail_open, 1831 .read = seq_read, 1832 .llseek = seq_lseek, 1833 .release = seq_release, 1834 }; 1835 1836 static const struct file_operations ftrace_set_event_fops = { 1837 .open = ftrace_event_set_open, 1838 .read = seq_read, 1839 .write = ftrace_event_write, 1840 .llseek = seq_lseek, 1841 .release = ftrace_event_release, 1842 }; 1843 1844 static const struct file_operations ftrace_set_event_pid_fops = { 1845 .open = ftrace_event_set_pid_open, 1846 .read = seq_read, 1847 .write = ftrace_event_pid_write, 1848 .llseek = seq_lseek, 1849 .release = ftrace_event_release, 1850 }; 1851 1852 static const struct file_operations ftrace_set_event_notrace_pid_fops = { 1853 .open = ftrace_event_set_npid_open, 1854 .read = seq_read, 1855 .write = ftrace_event_npid_write, 1856 .llseek = seq_lseek, 1857 .release = ftrace_event_release, 1858 }; 1859 1860 static const struct file_operations ftrace_enable_fops = { 1861 .open = tracing_open_generic, 1862 .read = event_enable_read, 1863 .write = event_enable_write, 1864 .llseek = default_llseek, 1865 }; 1866 1867 static const struct file_operations ftrace_event_format_fops = { 1868 .open = trace_format_open, 1869 .read = seq_read, 1870 .llseek = seq_lseek, 1871 .release = seq_release, 1872 }; 1873 1874 static const struct file_operations ftrace_event_id_fops = { 1875 .read = event_id_read, 1876 .llseek = default_llseek, 1877 }; 1878 1879 static const struct file_operations ftrace_event_filter_fops = { 1880 .open = tracing_open_generic, 1881 .read = event_filter_read, 1882 .write = event_filter_write, 1883 .llseek = default_llseek, 1884 }; 1885 1886 static const struct file_operations ftrace_subsystem_filter_fops = { 1887 .open = subsystem_open, 1888 .read = subsystem_filter_read, 1889 .write = subsystem_filter_write, 1890 .llseek = default_llseek, 1891 .release = subsystem_release, 1892 }; 1893 1894 static const struct file_operations ftrace_system_enable_fops = { 1895 .open = subsystem_open, 1896 .read = system_enable_read, 1897 .write = system_enable_write, 1898 .llseek = default_llseek, 1899 .release = subsystem_release, 1900 }; 1901 1902 static const struct file_operations ftrace_tr_enable_fops = { 1903 .open = system_tr_open, 1904 .read = system_enable_read, 1905 .write = system_enable_write, 1906 .llseek = default_llseek, 1907 .release = subsystem_release, 1908 }; 1909 1910 static const struct file_operations ftrace_show_header_fops = { 1911 .open = tracing_open_generic, 1912 .read = show_header, 1913 .llseek = default_llseek, 1914 }; 1915 1916 static int 1917 ftrace_event_open(struct inode *inode, struct file *file, 1918 const struct seq_operations *seq_ops) 1919 { 1920 struct seq_file *m; 1921 int ret; 1922 1923 ret = security_locked_down(LOCKDOWN_TRACEFS); 1924 if (ret) 1925 return ret; 1926 1927 ret = seq_open(file, seq_ops); 1928 if (ret < 0) 1929 return ret; 1930 m = file->private_data; 1931 /* copy tr over to seq ops */ 1932 m->private = inode->i_private; 1933 1934 return ret; 1935 } 1936 1937 static int ftrace_event_release(struct inode *inode, struct file *file) 1938 { 1939 struct trace_array *tr = inode->i_private; 1940 1941 trace_array_put(tr); 1942 1943 return seq_release(inode, file); 1944 } 1945 1946 static int 1947 ftrace_event_avail_open(struct inode *inode, struct file *file) 1948 { 1949 const struct seq_operations *seq_ops = &show_event_seq_ops; 1950 1951 /* Checks for tracefs lockdown */ 1952 return ftrace_event_open(inode, file, seq_ops); 1953 } 1954 1955 static int 1956 ftrace_event_set_open(struct inode *inode, struct file *file) 1957 { 1958 const struct seq_operations *seq_ops = &show_set_event_seq_ops; 1959 struct trace_array *tr = inode->i_private; 1960 int ret; 1961 1962 ret = tracing_check_open_get_tr(tr); 1963 if (ret) 1964 return ret; 1965 1966 if ((file->f_mode & FMODE_WRITE) && 1967 (file->f_flags & O_TRUNC)) 1968 ftrace_clear_events(tr); 1969 1970 ret = ftrace_event_open(inode, file, seq_ops); 1971 if (ret < 0) 1972 trace_array_put(tr); 1973 return ret; 1974 } 1975 1976 static int 1977 ftrace_event_set_pid_open(struct inode *inode, struct file *file) 1978 { 1979 const struct seq_operations *seq_ops = &show_set_pid_seq_ops; 1980 struct trace_array *tr = inode->i_private; 1981 int ret; 1982 1983 ret = tracing_check_open_get_tr(tr); 1984 if (ret) 1985 return ret; 1986 1987 if ((file->f_mode & FMODE_WRITE) && 1988 (file->f_flags & O_TRUNC)) 1989 ftrace_clear_event_pids(tr, TRACE_PIDS); 1990 1991 ret = ftrace_event_open(inode, file, seq_ops); 1992 if (ret < 0) 1993 trace_array_put(tr); 1994 return ret; 1995 } 1996 1997 static int 1998 ftrace_event_set_npid_open(struct inode *inode, struct file *file) 1999 { 2000 const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops; 2001 struct trace_array *tr = inode->i_private; 2002 int ret; 2003 2004 ret = tracing_check_open_get_tr(tr); 2005 if (ret) 2006 return ret; 2007 2008 if ((file->f_mode & FMODE_WRITE) && 2009 (file->f_flags & O_TRUNC)) 2010 ftrace_clear_event_pids(tr, TRACE_NO_PIDS); 2011 2012 ret = ftrace_event_open(inode, file, seq_ops); 2013 if (ret < 0) 2014 trace_array_put(tr); 2015 return ret; 2016 } 2017 2018 static struct event_subsystem * 2019 create_new_subsystem(const char *name) 2020 { 2021 struct event_subsystem *system; 2022 2023 /* need to create new entry */ 2024 system = kmalloc(sizeof(*system), GFP_KERNEL); 2025 if (!system) 2026 return NULL; 2027 2028 system->ref_count = 1; 2029 2030 /* Only allocate if dynamic (kprobes and modules) */ 2031 system->name = kstrdup_const(name, GFP_KERNEL); 2032 if (!system->name) 2033 goto out_free; 2034 2035 system->filter = NULL; 2036 2037 system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL); 2038 if (!system->filter) 2039 goto out_free; 2040 2041 list_add(&system->list, &event_subsystems); 2042 2043 return system; 2044 2045 out_free: 2046 kfree_const(system->name); 2047 kfree(system); 2048 return NULL; 2049 } 2050 2051 static struct dentry * 2052 event_subsystem_dir(struct trace_array *tr, const char *name, 2053 struct trace_event_file *file, struct dentry *parent) 2054 { 2055 struct trace_subsystem_dir *dir; 2056 struct event_subsystem *system; 2057 struct dentry *entry; 2058 2059 /* First see if we did not already create this dir */ 2060 list_for_each_entry(dir, &tr->systems, list) { 2061 system = dir->subsystem; 2062 if (strcmp(system->name, name) == 0) { 2063 dir->nr_events++; 2064 file->system = dir; 2065 return dir->entry; 2066 } 2067 } 2068 2069 /* Now see if the system itself exists. */ 2070 list_for_each_entry(system, &event_subsystems, list) { 2071 if (strcmp(system->name, name) == 0) 2072 break; 2073 } 2074 /* Reset system variable when not found */ 2075 if (&system->list == &event_subsystems) 2076 system = NULL; 2077 2078 dir = kmalloc(sizeof(*dir), GFP_KERNEL); 2079 if (!dir) 2080 goto out_fail; 2081 2082 if (!system) { 2083 system = create_new_subsystem(name); 2084 if (!system) 2085 goto out_free; 2086 } else 2087 __get_system(system); 2088 2089 dir->entry = tracefs_create_dir(name, parent); 2090 if (!dir->entry) { 2091 pr_warn("Failed to create system directory %s\n", name); 2092 __put_system(system); 2093 goto out_free; 2094 } 2095 2096 dir->tr = tr; 2097 dir->ref_count = 1; 2098 dir->nr_events = 1; 2099 dir->subsystem = system; 2100 file->system = dir; 2101 2102 entry = tracefs_create_file("filter", 0644, dir->entry, dir, 2103 &ftrace_subsystem_filter_fops); 2104 if (!entry) { 2105 kfree(system->filter); 2106 system->filter = NULL; 2107 pr_warn("Could not create tracefs '%s/filter' entry\n", name); 2108 } 2109 2110 trace_create_file("enable", 0644, dir->entry, dir, 2111 &ftrace_system_enable_fops); 2112 2113 list_add(&dir->list, &tr->systems); 2114 2115 return dir->entry; 2116 2117 out_free: 2118 kfree(dir); 2119 out_fail: 2120 /* Only print this message if failed on memory allocation */ 2121 if (!dir || !system) 2122 pr_warn("No memory to create event subsystem %s\n", name); 2123 return NULL; 2124 } 2125 2126 static int 2127 event_create_dir(struct dentry *parent, struct trace_event_file *file) 2128 { 2129 struct trace_event_call *call = file->event_call; 2130 struct trace_array *tr = file->tr; 2131 struct list_head *head; 2132 struct dentry *d_events; 2133 const char *name; 2134 int ret; 2135 2136 /* 2137 * If the trace point header did not define TRACE_SYSTEM 2138 * then the system would be called "TRACE_SYSTEM". 2139 */ 2140 if (strcmp(call->class->system, TRACE_SYSTEM) != 0) { 2141 d_events = event_subsystem_dir(tr, call->class->system, file, parent); 2142 if (!d_events) 2143 return -ENOMEM; 2144 } else 2145 d_events = parent; 2146 2147 name = trace_event_name(call); 2148 file->dir = tracefs_create_dir(name, d_events); 2149 if (!file->dir) { 2150 pr_warn("Could not create tracefs '%s' directory\n", name); 2151 return -1; 2152 } 2153 2154 if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) 2155 trace_create_file("enable", 0644, file->dir, file, 2156 &ftrace_enable_fops); 2157 2158 #ifdef CONFIG_PERF_EVENTS 2159 if (call->event.type && call->class->reg) 2160 trace_create_file("id", 0444, file->dir, 2161 (void *)(long)call->event.type, 2162 &ftrace_event_id_fops); 2163 #endif 2164 2165 /* 2166 * Other events may have the same class. Only update 2167 * the fields if they are not already defined. 2168 */ 2169 head = trace_get_fields(call); 2170 if (list_empty(head)) { 2171 struct trace_event_fields *field = call->class->fields_array; 2172 unsigned int offset = sizeof(struct trace_entry); 2173 2174 for (; field->type; field++) { 2175 if (field->type == TRACE_FUNCTION_TYPE) { 2176 ret = field->define_fields(call); 2177 break; 2178 } 2179 2180 offset = ALIGN(offset, field->align); 2181 ret = trace_define_field(call, field->type, field->name, 2182 offset, field->size, 2183 field->is_signed, field->filter_type); 2184 if (ret) 2185 break; 2186 2187 offset += field->size; 2188 } 2189 if (ret < 0) { 2190 pr_warn("Could not initialize trace point events/%s\n", 2191 name); 2192 return -1; 2193 } 2194 } 2195 2196 /* 2197 * Only event directories that can be enabled should have 2198 * triggers or filters. 2199 */ 2200 if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) { 2201 trace_create_file("filter", 0644, file->dir, file, 2202 &ftrace_event_filter_fops); 2203 2204 trace_create_file("trigger", 0644, file->dir, file, 2205 &event_trigger_fops); 2206 } 2207 2208 #ifdef CONFIG_HIST_TRIGGERS 2209 trace_create_file("hist", 0444, file->dir, file, 2210 &event_hist_fops); 2211 #endif 2212 #ifdef CONFIG_HIST_TRIGGERS_DEBUG 2213 trace_create_file("hist_debug", 0444, file->dir, file, 2214 &event_hist_debug_fops); 2215 #endif 2216 trace_create_file("format", 0444, file->dir, call, 2217 &ftrace_event_format_fops); 2218 2219 #ifdef CONFIG_TRACE_EVENT_INJECT 2220 if (call->event.type && call->class->reg) 2221 trace_create_file("inject", 0200, file->dir, file, 2222 &event_inject_fops); 2223 #endif 2224 2225 return 0; 2226 } 2227 2228 static void remove_event_from_tracers(struct trace_event_call *call) 2229 { 2230 struct trace_event_file *file; 2231 struct trace_array *tr; 2232 2233 do_for_each_event_file_safe(tr, file) { 2234 if (file->event_call != call) 2235 continue; 2236 2237 remove_event_file_dir(file); 2238 /* 2239 * The do_for_each_event_file_safe() is 2240 * a double loop. After finding the call for this 2241 * trace_array, we use break to jump to the next 2242 * trace_array. 2243 */ 2244 break; 2245 } while_for_each_event_file(); 2246 } 2247 2248 static void event_remove(struct trace_event_call *call) 2249 { 2250 struct trace_array *tr; 2251 struct trace_event_file *file; 2252 2253 do_for_each_event_file(tr, file) { 2254 if (file->event_call != call) 2255 continue; 2256 2257 if (file->flags & EVENT_FILE_FL_WAS_ENABLED) 2258 tr->clear_trace = true; 2259 2260 ftrace_event_enable_disable(file, 0); 2261 /* 2262 * The do_for_each_event_file() is 2263 * a double loop. After finding the call for this 2264 * trace_array, we use break to jump to the next 2265 * trace_array. 2266 */ 2267 break; 2268 } while_for_each_event_file(); 2269 2270 if (call->event.funcs) 2271 __unregister_trace_event(&call->event); 2272 remove_event_from_tracers(call); 2273 list_del(&call->list); 2274 } 2275 2276 static int event_init(struct trace_event_call *call) 2277 { 2278 int ret = 0; 2279 const char *name; 2280 2281 name = trace_event_name(call); 2282 if (WARN_ON(!name)) 2283 return -EINVAL; 2284 2285 if (call->class->raw_init) { 2286 ret = call->class->raw_init(call); 2287 if (ret < 0 && ret != -ENOSYS) 2288 pr_warn("Could not initialize trace events/%s\n", name); 2289 } 2290 2291 return ret; 2292 } 2293 2294 static int 2295 __register_event(struct trace_event_call *call, struct module *mod) 2296 { 2297 int ret; 2298 2299 ret = event_init(call); 2300 if (ret < 0) 2301 return ret; 2302 2303 list_add(&call->list, &ftrace_events); 2304 call->mod = mod; 2305 2306 return 0; 2307 } 2308 2309 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len) 2310 { 2311 int rlen; 2312 int elen; 2313 2314 /* Find the length of the eval value as a string */ 2315 elen = snprintf(ptr, 0, "%ld", map->eval_value); 2316 /* Make sure there's enough room to replace the string with the value */ 2317 if (len < elen) 2318 return NULL; 2319 2320 snprintf(ptr, elen + 1, "%ld", map->eval_value); 2321 2322 /* Get the rest of the string of ptr */ 2323 rlen = strlen(ptr + len); 2324 memmove(ptr + elen, ptr + len, rlen); 2325 /* Make sure we end the new string */ 2326 ptr[elen + rlen] = 0; 2327 2328 return ptr + elen; 2329 } 2330 2331 static void update_event_printk(struct trace_event_call *call, 2332 struct trace_eval_map *map) 2333 { 2334 char *ptr; 2335 int quote = 0; 2336 int len = strlen(map->eval_string); 2337 2338 for (ptr = call->print_fmt; *ptr; ptr++) { 2339 if (*ptr == '\\') { 2340 ptr++; 2341 /* paranoid */ 2342 if (!*ptr) 2343 break; 2344 continue; 2345 } 2346 if (*ptr == '"') { 2347 quote ^= 1; 2348 continue; 2349 } 2350 if (quote) 2351 continue; 2352 if (isdigit(*ptr)) { 2353 /* skip numbers */ 2354 do { 2355 ptr++; 2356 /* Check for alpha chars like ULL */ 2357 } while (isalnum(*ptr)); 2358 if (!*ptr) 2359 break; 2360 /* 2361 * A number must have some kind of delimiter after 2362 * it, and we can ignore that too. 2363 */ 2364 continue; 2365 } 2366 if (isalpha(*ptr) || *ptr == '_') { 2367 if (strncmp(map->eval_string, ptr, len) == 0 && 2368 !isalnum(ptr[len]) && ptr[len] != '_') { 2369 ptr = eval_replace(ptr, map, len); 2370 /* enum/sizeof string smaller than value */ 2371 if (WARN_ON_ONCE(!ptr)) 2372 return; 2373 /* 2374 * No need to decrement here, as eval_replace() 2375 * returns the pointer to the character passed 2376 * the eval, and two evals can not be placed 2377 * back to back without something in between. 2378 * We can skip that something in between. 2379 */ 2380 continue; 2381 } 2382 skip_more: 2383 do { 2384 ptr++; 2385 } while (isalnum(*ptr) || *ptr == '_'); 2386 if (!*ptr) 2387 break; 2388 /* 2389 * If what comes after this variable is a '.' or 2390 * '->' then we can continue to ignore that string. 2391 */ 2392 if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) { 2393 ptr += *ptr == '.' ? 1 : 2; 2394 if (!*ptr) 2395 break; 2396 goto skip_more; 2397 } 2398 /* 2399 * Once again, we can skip the delimiter that came 2400 * after the string. 2401 */ 2402 continue; 2403 } 2404 } 2405 } 2406 2407 void trace_event_eval_update(struct trace_eval_map **map, int len) 2408 { 2409 struct trace_event_call *call, *p; 2410 const char *last_system = NULL; 2411 bool first = false; 2412 int last_i; 2413 int i; 2414 2415 down_write(&trace_event_sem); 2416 list_for_each_entry_safe(call, p, &ftrace_events, list) { 2417 /* events are usually grouped together with systems */ 2418 if (!last_system || call->class->system != last_system) { 2419 first = true; 2420 last_i = 0; 2421 last_system = call->class->system; 2422 } 2423 2424 /* 2425 * Since calls are grouped by systems, the likelyhood that the 2426 * next call in the iteration belongs to the same system as the 2427 * previous call is high. As an optimization, we skip seaching 2428 * for a map[] that matches the call's system if the last call 2429 * was from the same system. That's what last_i is for. If the 2430 * call has the same system as the previous call, then last_i 2431 * will be the index of the first map[] that has a matching 2432 * system. 2433 */ 2434 for (i = last_i; i < len; i++) { 2435 if (call->class->system == map[i]->system) { 2436 /* Save the first system if need be */ 2437 if (first) { 2438 last_i = i; 2439 first = false; 2440 } 2441 update_event_printk(call, map[i]); 2442 } 2443 } 2444 } 2445 up_write(&trace_event_sem); 2446 } 2447 2448 static struct trace_event_file * 2449 trace_create_new_event(struct trace_event_call *call, 2450 struct trace_array *tr) 2451 { 2452 struct trace_event_file *file; 2453 2454 file = kmem_cache_alloc(file_cachep, GFP_TRACE); 2455 if (!file) 2456 return NULL; 2457 2458 file->event_call = call; 2459 file->tr = tr; 2460 atomic_set(&file->sm_ref, 0); 2461 atomic_set(&file->tm_ref, 0); 2462 INIT_LIST_HEAD(&file->triggers); 2463 list_add(&file->list, &tr->events); 2464 2465 return file; 2466 } 2467 2468 /* Add an event to a trace directory */ 2469 static int 2470 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr) 2471 { 2472 struct trace_event_file *file; 2473 2474 file = trace_create_new_event(call, tr); 2475 if (!file) 2476 return -ENOMEM; 2477 2478 return event_create_dir(tr->event_dir, file); 2479 } 2480 2481 /* 2482 * Just create a decriptor for early init. A descriptor is required 2483 * for enabling events at boot. We want to enable events before 2484 * the filesystem is initialized. 2485 */ 2486 static __init int 2487 __trace_early_add_new_event(struct trace_event_call *call, 2488 struct trace_array *tr) 2489 { 2490 struct trace_event_file *file; 2491 2492 file = trace_create_new_event(call, tr); 2493 if (!file) 2494 return -ENOMEM; 2495 2496 return 0; 2497 } 2498 2499 struct ftrace_module_file_ops; 2500 static void __add_event_to_tracers(struct trace_event_call *call); 2501 2502 /* Add an additional event_call dynamically */ 2503 int trace_add_event_call(struct trace_event_call *call) 2504 { 2505 int ret; 2506 lockdep_assert_held(&event_mutex); 2507 2508 mutex_lock(&trace_types_lock); 2509 2510 ret = __register_event(call, NULL); 2511 if (ret >= 0) 2512 __add_event_to_tracers(call); 2513 2514 mutex_unlock(&trace_types_lock); 2515 return ret; 2516 } 2517 2518 /* 2519 * Must be called under locking of trace_types_lock, event_mutex and 2520 * trace_event_sem. 2521 */ 2522 static void __trace_remove_event_call(struct trace_event_call *call) 2523 { 2524 event_remove(call); 2525 trace_destroy_fields(call); 2526 free_event_filter(call->filter); 2527 call->filter = NULL; 2528 } 2529 2530 static int probe_remove_event_call(struct trace_event_call *call) 2531 { 2532 struct trace_array *tr; 2533 struct trace_event_file *file; 2534 2535 #ifdef CONFIG_PERF_EVENTS 2536 if (call->perf_refcount) 2537 return -EBUSY; 2538 #endif 2539 do_for_each_event_file(tr, file) { 2540 if (file->event_call != call) 2541 continue; 2542 /* 2543 * We can't rely on ftrace_event_enable_disable(enable => 0) 2544 * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress 2545 * TRACE_REG_UNREGISTER. 2546 */ 2547 if (file->flags & EVENT_FILE_FL_ENABLED) 2548 return -EBUSY; 2549 /* 2550 * The do_for_each_event_file_safe() is 2551 * a double loop. After finding the call for this 2552 * trace_array, we use break to jump to the next 2553 * trace_array. 2554 */ 2555 break; 2556 } while_for_each_event_file(); 2557 2558 __trace_remove_event_call(call); 2559 2560 return 0; 2561 } 2562 2563 /* Remove an event_call */ 2564 int trace_remove_event_call(struct trace_event_call *call) 2565 { 2566 int ret; 2567 2568 lockdep_assert_held(&event_mutex); 2569 2570 mutex_lock(&trace_types_lock); 2571 down_write(&trace_event_sem); 2572 ret = probe_remove_event_call(call); 2573 up_write(&trace_event_sem); 2574 mutex_unlock(&trace_types_lock); 2575 2576 return ret; 2577 } 2578 2579 #define for_each_event(event, start, end) \ 2580 for (event = start; \ 2581 (unsigned long)event < (unsigned long)end; \ 2582 event++) 2583 2584 #ifdef CONFIG_MODULES 2585 2586 static void trace_module_add_events(struct module *mod) 2587 { 2588 struct trace_event_call **call, **start, **end; 2589 2590 if (!mod->num_trace_events) 2591 return; 2592 2593 /* Don't add infrastructure for mods without tracepoints */ 2594 if (trace_module_has_bad_taint(mod)) { 2595 pr_err("%s: module has bad taint, not creating trace events\n", 2596 mod->name); 2597 return; 2598 } 2599 2600 start = mod->trace_events; 2601 end = mod->trace_events + mod->num_trace_events; 2602 2603 for_each_event(call, start, end) { 2604 __register_event(*call, mod); 2605 __add_event_to_tracers(*call); 2606 } 2607 } 2608 2609 static void trace_module_remove_events(struct module *mod) 2610 { 2611 struct trace_event_call *call, *p; 2612 2613 down_write(&trace_event_sem); 2614 list_for_each_entry_safe(call, p, &ftrace_events, list) { 2615 if (call->mod == mod) 2616 __trace_remove_event_call(call); 2617 } 2618 up_write(&trace_event_sem); 2619 2620 /* 2621 * It is safest to reset the ring buffer if the module being unloaded 2622 * registered any events that were used. The only worry is if 2623 * a new module gets loaded, and takes on the same id as the events 2624 * of this module. When printing out the buffer, traced events left 2625 * over from this module may be passed to the new module events and 2626 * unexpected results may occur. 2627 */ 2628 tracing_reset_all_online_cpus(); 2629 } 2630 2631 static int trace_module_notify(struct notifier_block *self, 2632 unsigned long val, void *data) 2633 { 2634 struct module *mod = data; 2635 2636 mutex_lock(&event_mutex); 2637 mutex_lock(&trace_types_lock); 2638 switch (val) { 2639 case MODULE_STATE_COMING: 2640 trace_module_add_events(mod); 2641 break; 2642 case MODULE_STATE_GOING: 2643 trace_module_remove_events(mod); 2644 break; 2645 } 2646 mutex_unlock(&trace_types_lock); 2647 mutex_unlock(&event_mutex); 2648 2649 return 0; 2650 } 2651 2652 static struct notifier_block trace_module_nb = { 2653 .notifier_call = trace_module_notify, 2654 .priority = 1, /* higher than trace.c module notify */ 2655 }; 2656 #endif /* CONFIG_MODULES */ 2657 2658 /* Create a new event directory structure for a trace directory. */ 2659 static void 2660 __trace_add_event_dirs(struct trace_array *tr) 2661 { 2662 struct trace_event_call *call; 2663 int ret; 2664 2665 list_for_each_entry(call, &ftrace_events, list) { 2666 ret = __trace_add_new_event(call, tr); 2667 if (ret < 0) 2668 pr_warn("Could not create directory for event %s\n", 2669 trace_event_name(call)); 2670 } 2671 } 2672 2673 /* Returns any file that matches the system and event */ 2674 struct trace_event_file * 2675 __find_event_file(struct trace_array *tr, const char *system, const char *event) 2676 { 2677 struct trace_event_file *file; 2678 struct trace_event_call *call; 2679 const char *name; 2680 2681 list_for_each_entry(file, &tr->events, list) { 2682 2683 call = file->event_call; 2684 name = trace_event_name(call); 2685 2686 if (!name || !call->class) 2687 continue; 2688 2689 if (strcmp(event, name) == 0 && 2690 strcmp(system, call->class->system) == 0) 2691 return file; 2692 } 2693 return NULL; 2694 } 2695 2696 /* Returns valid trace event files that match system and event */ 2697 struct trace_event_file * 2698 find_event_file(struct trace_array *tr, const char *system, const char *event) 2699 { 2700 struct trace_event_file *file; 2701 2702 file = __find_event_file(tr, system, event); 2703 if (!file || !file->event_call->class->reg || 2704 file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) 2705 return NULL; 2706 2707 return file; 2708 } 2709 2710 /** 2711 * trace_get_event_file - Find and return a trace event file 2712 * @instance: The name of the trace instance containing the event 2713 * @system: The name of the system containing the event 2714 * @event: The name of the event 2715 * 2716 * Return a trace event file given the trace instance name, trace 2717 * system, and trace event name. If the instance name is NULL, it 2718 * refers to the top-level trace array. 2719 * 2720 * This function will look it up and return it if found, after calling 2721 * trace_array_get() to prevent the instance from going away, and 2722 * increment the event's module refcount to prevent it from being 2723 * removed. 2724 * 2725 * To release the file, call trace_put_event_file(), which will call 2726 * trace_array_put() and decrement the event's module refcount. 2727 * 2728 * Return: The trace event on success, ERR_PTR otherwise. 2729 */ 2730 struct trace_event_file *trace_get_event_file(const char *instance, 2731 const char *system, 2732 const char *event) 2733 { 2734 struct trace_array *tr = top_trace_array(); 2735 struct trace_event_file *file = NULL; 2736 int ret = -EINVAL; 2737 2738 if (instance) { 2739 tr = trace_array_find_get(instance); 2740 if (!tr) 2741 return ERR_PTR(-ENOENT); 2742 } else { 2743 ret = trace_array_get(tr); 2744 if (ret) 2745 return ERR_PTR(ret); 2746 } 2747 2748 mutex_lock(&event_mutex); 2749 2750 file = find_event_file(tr, system, event); 2751 if (!file) { 2752 trace_array_put(tr); 2753 ret = -EINVAL; 2754 goto out; 2755 } 2756 2757 /* Don't let event modules unload while in use */ 2758 ret = try_module_get(file->event_call->mod); 2759 if (!ret) { 2760 trace_array_put(tr); 2761 ret = -EBUSY; 2762 goto out; 2763 } 2764 2765 ret = 0; 2766 out: 2767 mutex_unlock(&event_mutex); 2768 2769 if (ret) 2770 file = ERR_PTR(ret); 2771 2772 return file; 2773 } 2774 EXPORT_SYMBOL_GPL(trace_get_event_file); 2775 2776 /** 2777 * trace_put_event_file - Release a file from trace_get_event_file() 2778 * @file: The trace event file 2779 * 2780 * If a file was retrieved using trace_get_event_file(), this should 2781 * be called when it's no longer needed. It will cancel the previous 2782 * trace_array_get() called by that function, and decrement the 2783 * event's module refcount. 2784 */ 2785 void trace_put_event_file(struct trace_event_file *file) 2786 { 2787 mutex_lock(&event_mutex); 2788 module_put(file->event_call->mod); 2789 mutex_unlock(&event_mutex); 2790 2791 trace_array_put(file->tr); 2792 } 2793 EXPORT_SYMBOL_GPL(trace_put_event_file); 2794 2795 #ifdef CONFIG_DYNAMIC_FTRACE 2796 2797 /* Avoid typos */ 2798 #define ENABLE_EVENT_STR "enable_event" 2799 #define DISABLE_EVENT_STR "disable_event" 2800 2801 struct event_probe_data { 2802 struct trace_event_file *file; 2803 unsigned long count; 2804 int ref; 2805 bool enable; 2806 }; 2807 2808 static void update_event_probe(struct event_probe_data *data) 2809 { 2810 if (data->enable) 2811 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags); 2812 else 2813 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags); 2814 } 2815 2816 static void 2817 event_enable_probe(unsigned long ip, unsigned long parent_ip, 2818 struct trace_array *tr, struct ftrace_probe_ops *ops, 2819 void *data) 2820 { 2821 struct ftrace_func_mapper *mapper = data; 2822 struct event_probe_data *edata; 2823 void **pdata; 2824 2825 pdata = ftrace_func_mapper_find_ip(mapper, ip); 2826 if (!pdata || !*pdata) 2827 return; 2828 2829 edata = *pdata; 2830 update_event_probe(edata); 2831 } 2832 2833 static void 2834 event_enable_count_probe(unsigned long ip, unsigned long parent_ip, 2835 struct trace_array *tr, struct ftrace_probe_ops *ops, 2836 void *data) 2837 { 2838 struct ftrace_func_mapper *mapper = data; 2839 struct event_probe_data *edata; 2840 void **pdata; 2841 2842 pdata = ftrace_func_mapper_find_ip(mapper, ip); 2843 if (!pdata || !*pdata) 2844 return; 2845 2846 edata = *pdata; 2847 2848 if (!edata->count) 2849 return; 2850 2851 /* Skip if the event is in a state we want to switch to */ 2852 if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED)) 2853 return; 2854 2855 if (edata->count != -1) 2856 (edata->count)--; 2857 2858 update_event_probe(edata); 2859 } 2860 2861 static int 2862 event_enable_print(struct seq_file *m, unsigned long ip, 2863 struct ftrace_probe_ops *ops, void *data) 2864 { 2865 struct ftrace_func_mapper *mapper = data; 2866 struct event_probe_data *edata; 2867 void **pdata; 2868 2869 pdata = ftrace_func_mapper_find_ip(mapper, ip); 2870 2871 if (WARN_ON_ONCE(!pdata || !*pdata)) 2872 return 0; 2873 2874 edata = *pdata; 2875 2876 seq_printf(m, "%ps:", (void *)ip); 2877 2878 seq_printf(m, "%s:%s:%s", 2879 edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR, 2880 edata->file->event_call->class->system, 2881 trace_event_name(edata->file->event_call)); 2882 2883 if (edata->count == -1) 2884 seq_puts(m, ":unlimited\n"); 2885 else 2886 seq_printf(m, ":count=%ld\n", edata->count); 2887 2888 return 0; 2889 } 2890 2891 static int 2892 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr, 2893 unsigned long ip, void *init_data, void **data) 2894 { 2895 struct ftrace_func_mapper *mapper = *data; 2896 struct event_probe_data *edata = init_data; 2897 int ret; 2898 2899 if (!mapper) { 2900 mapper = allocate_ftrace_func_mapper(); 2901 if (!mapper) 2902 return -ENODEV; 2903 *data = mapper; 2904 } 2905 2906 ret = ftrace_func_mapper_add_ip(mapper, ip, edata); 2907 if (ret < 0) 2908 return ret; 2909 2910 edata->ref++; 2911 2912 return 0; 2913 } 2914 2915 static int free_probe_data(void *data) 2916 { 2917 struct event_probe_data *edata = data; 2918 2919 edata->ref--; 2920 if (!edata->ref) { 2921 /* Remove the SOFT_MODE flag */ 2922 __ftrace_event_enable_disable(edata->file, 0, 1); 2923 module_put(edata->file->event_call->mod); 2924 kfree(edata); 2925 } 2926 return 0; 2927 } 2928 2929 static void 2930 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr, 2931 unsigned long ip, void *data) 2932 { 2933 struct ftrace_func_mapper *mapper = data; 2934 struct event_probe_data *edata; 2935 2936 if (!ip) { 2937 if (!mapper) 2938 return; 2939 free_ftrace_func_mapper(mapper, free_probe_data); 2940 return; 2941 } 2942 2943 edata = ftrace_func_mapper_remove_ip(mapper, ip); 2944 2945 if (WARN_ON_ONCE(!edata)) 2946 return; 2947 2948 if (WARN_ON_ONCE(edata->ref <= 0)) 2949 return; 2950 2951 free_probe_data(edata); 2952 } 2953 2954 static struct ftrace_probe_ops event_enable_probe_ops = { 2955 .func = event_enable_probe, 2956 .print = event_enable_print, 2957 .init = event_enable_init, 2958 .free = event_enable_free, 2959 }; 2960 2961 static struct ftrace_probe_ops event_enable_count_probe_ops = { 2962 .func = event_enable_count_probe, 2963 .print = event_enable_print, 2964 .init = event_enable_init, 2965 .free = event_enable_free, 2966 }; 2967 2968 static struct ftrace_probe_ops event_disable_probe_ops = { 2969 .func = event_enable_probe, 2970 .print = event_enable_print, 2971 .init = event_enable_init, 2972 .free = event_enable_free, 2973 }; 2974 2975 static struct ftrace_probe_ops event_disable_count_probe_ops = { 2976 .func = event_enable_count_probe, 2977 .print = event_enable_print, 2978 .init = event_enable_init, 2979 .free = event_enable_free, 2980 }; 2981 2982 static int 2983 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash, 2984 char *glob, char *cmd, char *param, int enabled) 2985 { 2986 struct trace_event_file *file; 2987 struct ftrace_probe_ops *ops; 2988 struct event_probe_data *data; 2989 const char *system; 2990 const char *event; 2991 char *number; 2992 bool enable; 2993 int ret; 2994 2995 if (!tr) 2996 return -ENODEV; 2997 2998 /* hash funcs only work with set_ftrace_filter */ 2999 if (!enabled || !param) 3000 return -EINVAL; 3001 3002 system = strsep(¶m, ":"); 3003 if (!param) 3004 return -EINVAL; 3005 3006 event = strsep(¶m, ":"); 3007 3008 mutex_lock(&event_mutex); 3009 3010 ret = -EINVAL; 3011 file = find_event_file(tr, system, event); 3012 if (!file) 3013 goto out; 3014 3015 enable = strcmp(cmd, ENABLE_EVENT_STR) == 0; 3016 3017 if (enable) 3018 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops; 3019 else 3020 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops; 3021 3022 if (glob[0] == '!') { 3023 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops); 3024 goto out; 3025 } 3026 3027 ret = -ENOMEM; 3028 3029 data = kzalloc(sizeof(*data), GFP_KERNEL); 3030 if (!data) 3031 goto out; 3032 3033 data->enable = enable; 3034 data->count = -1; 3035 data->file = file; 3036 3037 if (!param) 3038 goto out_reg; 3039 3040 number = strsep(¶m, ":"); 3041 3042 ret = -EINVAL; 3043 if (!strlen(number)) 3044 goto out_free; 3045 3046 /* 3047 * We use the callback data field (which is a pointer) 3048 * as our counter. 3049 */ 3050 ret = kstrtoul(number, 0, &data->count); 3051 if (ret) 3052 goto out_free; 3053 3054 out_reg: 3055 /* Don't let event modules unload while probe registered */ 3056 ret = try_module_get(file->event_call->mod); 3057 if (!ret) { 3058 ret = -EBUSY; 3059 goto out_free; 3060 } 3061 3062 ret = __ftrace_event_enable_disable(file, 1, 1); 3063 if (ret < 0) 3064 goto out_put; 3065 3066 ret = register_ftrace_function_probe(glob, tr, ops, data); 3067 /* 3068 * The above returns on success the # of functions enabled, 3069 * but if it didn't find any functions it returns zero. 3070 * Consider no functions a failure too. 3071 */ 3072 if (!ret) { 3073 ret = -ENOENT; 3074 goto out_disable; 3075 } else if (ret < 0) 3076 goto out_disable; 3077 /* Just return zero, not the number of enabled functions */ 3078 ret = 0; 3079 out: 3080 mutex_unlock(&event_mutex); 3081 return ret; 3082 3083 out_disable: 3084 __ftrace_event_enable_disable(file, 0, 1); 3085 out_put: 3086 module_put(file->event_call->mod); 3087 out_free: 3088 kfree(data); 3089 goto out; 3090 } 3091 3092 static struct ftrace_func_command event_enable_cmd = { 3093 .name = ENABLE_EVENT_STR, 3094 .func = event_enable_func, 3095 }; 3096 3097 static struct ftrace_func_command event_disable_cmd = { 3098 .name = DISABLE_EVENT_STR, 3099 .func = event_enable_func, 3100 }; 3101 3102 static __init int register_event_cmds(void) 3103 { 3104 int ret; 3105 3106 ret = register_ftrace_command(&event_enable_cmd); 3107 if (WARN_ON(ret < 0)) 3108 return ret; 3109 ret = register_ftrace_command(&event_disable_cmd); 3110 if (WARN_ON(ret < 0)) 3111 unregister_ftrace_command(&event_enable_cmd); 3112 return ret; 3113 } 3114 #else 3115 static inline int register_event_cmds(void) { return 0; } 3116 #endif /* CONFIG_DYNAMIC_FTRACE */ 3117 3118 /* 3119 * The top level array has already had its trace_event_file 3120 * descriptors created in order to allow for early events to 3121 * be recorded. This function is called after the tracefs has been 3122 * initialized, and we now have to create the files associated 3123 * to the events. 3124 */ 3125 static __init void 3126 __trace_early_add_event_dirs(struct trace_array *tr) 3127 { 3128 struct trace_event_file *file; 3129 int ret; 3130 3131 3132 list_for_each_entry(file, &tr->events, list) { 3133 ret = event_create_dir(tr->event_dir, file); 3134 if (ret < 0) 3135 pr_warn("Could not create directory for event %s\n", 3136 trace_event_name(file->event_call)); 3137 } 3138 } 3139 3140 /* 3141 * For early boot up, the top trace array requires to have 3142 * a list of events that can be enabled. This must be done before 3143 * the filesystem is set up in order to allow events to be traced 3144 * early. 3145 */ 3146 static __init void 3147 __trace_early_add_events(struct trace_array *tr) 3148 { 3149 struct trace_event_call *call; 3150 int ret; 3151 3152 list_for_each_entry(call, &ftrace_events, list) { 3153 /* Early boot up should not have any modules loaded */ 3154 if (WARN_ON_ONCE(call->mod)) 3155 continue; 3156 3157 ret = __trace_early_add_new_event(call, tr); 3158 if (ret < 0) 3159 pr_warn("Could not create early event %s\n", 3160 trace_event_name(call)); 3161 } 3162 } 3163 3164 /* Remove the event directory structure for a trace directory. */ 3165 static void 3166 __trace_remove_event_dirs(struct trace_array *tr) 3167 { 3168 struct trace_event_file *file, *next; 3169 3170 list_for_each_entry_safe(file, next, &tr->events, list) 3171 remove_event_file_dir(file); 3172 } 3173 3174 static void __add_event_to_tracers(struct trace_event_call *call) 3175 { 3176 struct trace_array *tr; 3177 3178 list_for_each_entry(tr, &ftrace_trace_arrays, list) 3179 __trace_add_new_event(call, tr); 3180 } 3181 3182 extern struct trace_event_call *__start_ftrace_events[]; 3183 extern struct trace_event_call *__stop_ftrace_events[]; 3184 3185 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata; 3186 3187 static __init int setup_trace_event(char *str) 3188 { 3189 strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE); 3190 ring_buffer_expanded = true; 3191 tracing_selftest_disabled = true; 3192 3193 return 1; 3194 } 3195 __setup("trace_event=", setup_trace_event); 3196 3197 /* Expects to have event_mutex held when called */ 3198 static int 3199 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) 3200 { 3201 struct dentry *d_events; 3202 struct dentry *entry; 3203 3204 entry = tracefs_create_file("set_event", 0644, parent, 3205 tr, &ftrace_set_event_fops); 3206 if (!entry) { 3207 pr_warn("Could not create tracefs 'set_event' entry\n"); 3208 return -ENOMEM; 3209 } 3210 3211 d_events = tracefs_create_dir("events", parent); 3212 if (!d_events) { 3213 pr_warn("Could not create tracefs 'events' directory\n"); 3214 return -ENOMEM; 3215 } 3216 3217 entry = trace_create_file("enable", 0644, d_events, 3218 tr, &ftrace_tr_enable_fops); 3219 if (!entry) { 3220 pr_warn("Could not create tracefs 'enable' entry\n"); 3221 return -ENOMEM; 3222 } 3223 3224 /* There are not as crucial, just warn if they are not created */ 3225 3226 entry = tracefs_create_file("set_event_pid", 0644, parent, 3227 tr, &ftrace_set_event_pid_fops); 3228 if (!entry) 3229 pr_warn("Could not create tracefs 'set_event_pid' entry\n"); 3230 3231 entry = tracefs_create_file("set_event_notrace_pid", 0644, parent, 3232 tr, &ftrace_set_event_notrace_pid_fops); 3233 if (!entry) 3234 pr_warn("Could not create tracefs 'set_event_notrace_pid' entry\n"); 3235 3236 /* ring buffer internal formats */ 3237 entry = trace_create_file("header_page", 0444, d_events, 3238 ring_buffer_print_page_header, 3239 &ftrace_show_header_fops); 3240 if (!entry) 3241 pr_warn("Could not create tracefs 'header_page' entry\n"); 3242 3243 entry = trace_create_file("header_event", 0444, d_events, 3244 ring_buffer_print_entry_header, 3245 &ftrace_show_header_fops); 3246 if (!entry) 3247 pr_warn("Could not create tracefs 'header_event' entry\n"); 3248 3249 tr->event_dir = d_events; 3250 3251 return 0; 3252 } 3253 3254 /** 3255 * event_trace_add_tracer - add a instance of a trace_array to events 3256 * @parent: The parent dentry to place the files/directories for events in 3257 * @tr: The trace array associated with these events 3258 * 3259 * When a new instance is created, it needs to set up its events 3260 * directory, as well as other files associated with events. It also 3261 * creates the event hierachry in the @parent/events directory. 3262 * 3263 * Returns 0 on success. 3264 * 3265 * Must be called with event_mutex held. 3266 */ 3267 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr) 3268 { 3269 int ret; 3270 3271 lockdep_assert_held(&event_mutex); 3272 3273 ret = create_event_toplevel_files(parent, tr); 3274 if (ret) 3275 goto out; 3276 3277 down_write(&trace_event_sem); 3278 __trace_add_event_dirs(tr); 3279 up_write(&trace_event_sem); 3280 3281 out: 3282 return ret; 3283 } 3284 3285 /* 3286 * The top trace array already had its file descriptors created. 3287 * Now the files themselves need to be created. 3288 */ 3289 static __init int 3290 early_event_add_tracer(struct dentry *parent, struct trace_array *tr) 3291 { 3292 int ret; 3293 3294 mutex_lock(&event_mutex); 3295 3296 ret = create_event_toplevel_files(parent, tr); 3297 if (ret) 3298 goto out_unlock; 3299 3300 down_write(&trace_event_sem); 3301 __trace_early_add_event_dirs(tr); 3302 up_write(&trace_event_sem); 3303 3304 out_unlock: 3305 mutex_unlock(&event_mutex); 3306 3307 return ret; 3308 } 3309 3310 /* Must be called with event_mutex held */ 3311 int event_trace_del_tracer(struct trace_array *tr) 3312 { 3313 lockdep_assert_held(&event_mutex); 3314 3315 /* Disable any event triggers and associated soft-disabled events */ 3316 clear_event_triggers(tr); 3317 3318 /* Clear the pid list */ 3319 __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS); 3320 3321 /* Disable any running events */ 3322 __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0); 3323 3324 /* Make sure no more events are being executed */ 3325 tracepoint_synchronize_unregister(); 3326 3327 down_write(&trace_event_sem); 3328 __trace_remove_event_dirs(tr); 3329 tracefs_remove(tr->event_dir); 3330 up_write(&trace_event_sem); 3331 3332 tr->event_dir = NULL; 3333 3334 return 0; 3335 } 3336 3337 static __init int event_trace_memsetup(void) 3338 { 3339 field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC); 3340 file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC); 3341 return 0; 3342 } 3343 3344 static __init void 3345 early_enable_events(struct trace_array *tr, bool disable_first) 3346 { 3347 char *buf = bootup_event_buf; 3348 char *token; 3349 int ret; 3350 3351 while (true) { 3352 token = strsep(&buf, ","); 3353 3354 if (!token) 3355 break; 3356 3357 if (*token) { 3358 /* Restarting syscalls requires that we stop them first */ 3359 if (disable_first) 3360 ftrace_set_clr_event(tr, token, 0); 3361 3362 ret = ftrace_set_clr_event(tr, token, 1); 3363 if (ret) 3364 pr_warn("Failed to enable trace event: %s\n", token); 3365 } 3366 3367 /* Put back the comma to allow this to be called again */ 3368 if (buf) 3369 *(buf - 1) = ','; 3370 } 3371 } 3372 3373 static __init int event_trace_enable(void) 3374 { 3375 struct trace_array *tr = top_trace_array(); 3376 struct trace_event_call **iter, *call; 3377 int ret; 3378 3379 if (!tr) 3380 return -ENODEV; 3381 3382 for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) { 3383 3384 call = *iter; 3385 ret = event_init(call); 3386 if (!ret) 3387 list_add(&call->list, &ftrace_events); 3388 } 3389 3390 /* 3391 * We need the top trace array to have a working set of trace 3392 * points at early init, before the debug files and directories 3393 * are created. Create the file entries now, and attach them 3394 * to the actual file dentries later. 3395 */ 3396 __trace_early_add_events(tr); 3397 3398 early_enable_events(tr, false); 3399 3400 trace_printk_start_comm(); 3401 3402 register_event_cmds(); 3403 3404 register_trigger_cmds(); 3405 3406 return 0; 3407 } 3408 3409 /* 3410 * event_trace_enable() is called from trace_event_init() first to 3411 * initialize events and perhaps start any events that are on the 3412 * command line. Unfortunately, there are some events that will not 3413 * start this early, like the system call tracepoints that need 3414 * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable() 3415 * is called before pid 1 starts, and this flag is never set, making 3416 * the syscall tracepoint never get reached, but the event is enabled 3417 * regardless (and not doing anything). 3418 */ 3419 static __init int event_trace_enable_again(void) 3420 { 3421 struct trace_array *tr; 3422 3423 tr = top_trace_array(); 3424 if (!tr) 3425 return -ENODEV; 3426 3427 early_enable_events(tr, true); 3428 3429 return 0; 3430 } 3431 3432 early_initcall(event_trace_enable_again); 3433 3434 __init int event_trace_init(void) 3435 { 3436 struct trace_array *tr; 3437 struct dentry *d_tracer; 3438 struct dentry *entry; 3439 int ret; 3440 3441 tr = top_trace_array(); 3442 if (!tr) 3443 return -ENODEV; 3444 3445 d_tracer = tracing_init_dentry(); 3446 if (IS_ERR(d_tracer)) 3447 return 0; 3448 3449 entry = tracefs_create_file("available_events", 0444, d_tracer, 3450 tr, &ftrace_avail_fops); 3451 if (!entry) 3452 pr_warn("Could not create tracefs 'available_events' entry\n"); 3453 3454 if (trace_define_generic_fields()) 3455 pr_warn("tracing: Failed to allocated generic fields"); 3456 3457 if (trace_define_common_fields()) 3458 pr_warn("tracing: Failed to allocate common fields"); 3459 3460 ret = early_event_add_tracer(d_tracer, tr); 3461 if (ret) 3462 return ret; 3463 3464 #ifdef CONFIG_MODULES 3465 ret = register_module_notifier(&trace_module_nb); 3466 if (ret) 3467 pr_warn("Failed to register trace events module notifier\n"); 3468 #endif 3469 return 0; 3470 } 3471 3472 void __init trace_event_init(void) 3473 { 3474 event_trace_memsetup(); 3475 init_ftrace_syscalls(); 3476 event_trace_enable(); 3477 } 3478 3479 #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST 3480 3481 static DEFINE_SPINLOCK(test_spinlock); 3482 static DEFINE_SPINLOCK(test_spinlock_irq); 3483 static DEFINE_MUTEX(test_mutex); 3484 3485 static __init void test_work(struct work_struct *dummy) 3486 { 3487 spin_lock(&test_spinlock); 3488 spin_lock_irq(&test_spinlock_irq); 3489 udelay(1); 3490 spin_unlock_irq(&test_spinlock_irq); 3491 spin_unlock(&test_spinlock); 3492 3493 mutex_lock(&test_mutex); 3494 msleep(1); 3495 mutex_unlock(&test_mutex); 3496 } 3497 3498 static __init int event_test_thread(void *unused) 3499 { 3500 void *test_malloc; 3501 3502 test_malloc = kmalloc(1234, GFP_KERNEL); 3503 if (!test_malloc) 3504 pr_info("failed to kmalloc\n"); 3505 3506 schedule_on_each_cpu(test_work); 3507 3508 kfree(test_malloc); 3509 3510 set_current_state(TASK_INTERRUPTIBLE); 3511 while (!kthread_should_stop()) { 3512 schedule(); 3513 set_current_state(TASK_INTERRUPTIBLE); 3514 } 3515 __set_current_state(TASK_RUNNING); 3516 3517 return 0; 3518 } 3519 3520 /* 3521 * Do various things that may trigger events. 3522 */ 3523 static __init void event_test_stuff(void) 3524 { 3525 struct task_struct *test_thread; 3526 3527 test_thread = kthread_run(event_test_thread, NULL, "test-events"); 3528 msleep(1); 3529 kthread_stop(test_thread); 3530 } 3531 3532 /* 3533 * For every trace event defined, we will test each trace point separately, 3534 * and then by groups, and finally all trace points. 3535 */ 3536 static __init void event_trace_self_tests(void) 3537 { 3538 struct trace_subsystem_dir *dir; 3539 struct trace_event_file *file; 3540 struct trace_event_call *call; 3541 struct event_subsystem *system; 3542 struct trace_array *tr; 3543 int ret; 3544 3545 tr = top_trace_array(); 3546 if (!tr) 3547 return; 3548 3549 pr_info("Running tests on trace events:\n"); 3550 3551 list_for_each_entry(file, &tr->events, list) { 3552 3553 call = file->event_call; 3554 3555 /* Only test those that have a probe */ 3556 if (!call->class || !call->class->probe) 3557 continue; 3558 3559 /* 3560 * Testing syscall events here is pretty useless, but 3561 * we still do it if configured. But this is time consuming. 3562 * What we really need is a user thread to perform the 3563 * syscalls as we test. 3564 */ 3565 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS 3566 if (call->class->system && 3567 strcmp(call->class->system, "syscalls") == 0) 3568 continue; 3569 #endif 3570 3571 pr_info("Testing event %s: ", trace_event_name(call)); 3572 3573 /* 3574 * If an event is already enabled, someone is using 3575 * it and the self test should not be on. 3576 */ 3577 if (file->flags & EVENT_FILE_FL_ENABLED) { 3578 pr_warn("Enabled event during self test!\n"); 3579 WARN_ON_ONCE(1); 3580 continue; 3581 } 3582 3583 ftrace_event_enable_disable(file, 1); 3584 event_test_stuff(); 3585 ftrace_event_enable_disable(file, 0); 3586 3587 pr_cont("OK\n"); 3588 } 3589 3590 /* Now test at the sub system level */ 3591 3592 pr_info("Running tests on trace event systems:\n"); 3593 3594 list_for_each_entry(dir, &tr->systems, list) { 3595 3596 system = dir->subsystem; 3597 3598 /* the ftrace system is special, skip it */ 3599 if (strcmp(system->name, "ftrace") == 0) 3600 continue; 3601 3602 pr_info("Testing event system %s: ", system->name); 3603 3604 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1); 3605 if (WARN_ON_ONCE(ret)) { 3606 pr_warn("error enabling system %s\n", 3607 system->name); 3608 continue; 3609 } 3610 3611 event_test_stuff(); 3612 3613 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0); 3614 if (WARN_ON_ONCE(ret)) { 3615 pr_warn("error disabling system %s\n", 3616 system->name); 3617 continue; 3618 } 3619 3620 pr_cont("OK\n"); 3621 } 3622 3623 /* Test with all events enabled */ 3624 3625 pr_info("Running tests on all trace events:\n"); 3626 pr_info("Testing all events: "); 3627 3628 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1); 3629 if (WARN_ON_ONCE(ret)) { 3630 pr_warn("error enabling all events\n"); 3631 return; 3632 } 3633 3634 event_test_stuff(); 3635 3636 /* reset sysname */ 3637 ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0); 3638 if (WARN_ON_ONCE(ret)) { 3639 pr_warn("error disabling all events\n"); 3640 return; 3641 } 3642 3643 pr_cont("OK\n"); 3644 } 3645 3646 #ifdef CONFIG_FUNCTION_TRACER 3647 3648 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable); 3649 3650 static struct trace_event_file event_trace_file __initdata; 3651 3652 static void __init 3653 function_test_events_call(unsigned long ip, unsigned long parent_ip, 3654 struct ftrace_ops *op, struct pt_regs *pt_regs) 3655 { 3656 struct trace_buffer *buffer; 3657 struct ring_buffer_event *event; 3658 struct ftrace_entry *entry; 3659 unsigned long flags; 3660 long disabled; 3661 int cpu; 3662 int pc; 3663 3664 pc = preempt_count(); 3665 preempt_disable_notrace(); 3666 cpu = raw_smp_processor_id(); 3667 disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu)); 3668 3669 if (disabled != 1) 3670 goto out; 3671 3672 local_save_flags(flags); 3673 3674 event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file, 3675 TRACE_FN, sizeof(*entry), 3676 flags, pc); 3677 if (!event) 3678 goto out; 3679 entry = ring_buffer_event_data(event); 3680 entry->ip = ip; 3681 entry->parent_ip = parent_ip; 3682 3683 event_trigger_unlock_commit(&event_trace_file, buffer, event, 3684 entry, flags, pc); 3685 out: 3686 atomic_dec(&per_cpu(ftrace_test_event_disable, cpu)); 3687 preempt_enable_notrace(); 3688 } 3689 3690 static struct ftrace_ops trace_ops __initdata = 3691 { 3692 .func = function_test_events_call, 3693 .flags = FTRACE_OPS_FL_RECURSION_SAFE, 3694 }; 3695 3696 static __init void event_trace_self_test_with_function(void) 3697 { 3698 int ret; 3699 3700 event_trace_file.tr = top_trace_array(); 3701 if (WARN_ON(!event_trace_file.tr)) 3702 return; 3703 3704 ret = register_ftrace_function(&trace_ops); 3705 if (WARN_ON(ret < 0)) { 3706 pr_info("Failed to enable function tracer for event tests\n"); 3707 return; 3708 } 3709 pr_info("Running tests again, along with the function tracer\n"); 3710 event_trace_self_tests(); 3711 unregister_ftrace_function(&trace_ops); 3712 } 3713 #else 3714 static __init void event_trace_self_test_with_function(void) 3715 { 3716 } 3717 #endif 3718 3719 static __init int event_trace_self_tests_init(void) 3720 { 3721 if (!tracing_selftest_disabled) { 3722 event_trace_self_tests(); 3723 event_trace_self_test_with_function(); 3724 } 3725 3726 return 0; 3727 } 3728 3729 late_initcall(event_trace_self_tests_init); 3730 3731 #endif 3732